序 在经济全球化和国际交往日益频繁的今天，无论是作为个人还是组织的一员，参与国际交流 与合作都需要具备良好的外语沟通能力和扎实的专业技术能力。高职院校承担着培养具有全球竞争 力的高端技术人才的使命，需要探索如何有效地培养学生的行业外语能力。行业外语教学一直是职 业院校的短板，缺少合适的教材是其中一个主要原因。目前，国内大多数高职院校在第一学年开设 公共英语课程，所用教材多为通用英语教材，其主题与学生所学专业的关联度总体较低；部分院校 自主开发的行业英语教材，在专业内容的系统性、语言表达的准确性等方面存在诸多不足；还有部 分院校直接采用国外原版的大学本科或研究生教材，但这些教材学术性和专业性太强，对以就业为 导向的高职院校学生来说，十分晦涩难懂。 清华大学出版社从欧洲引进原版素材并组织国内一线行业英语教师改编的这套“新时代行业 英语系列教材”，以提升学生职业英语能力为目标，服务师生教与学。本套教材具有如下特点： 一、编写理念突出全球化和国际化 本套教材在欧洲原版引进优质资源的基础上改编而成，全球化视角选材，结合行业领域和单 元主题，关注环境保护、人口老龄化、贫困等时代难题，培养学生的国际视野和世界公民素养。单 元主题、板块编排和练习设计与国际接轨，体现国际规范和国际标准，且反映全球行业发展动态和 前景，帮助学生全面了解全球行业现状和掌握国际操作流程，夯实行业知识体系。 二、编写目标注重培养学生使用英语完成工作任务的实际应用能力 为响应高职院校外语教学改革号召，培养具有国际竞争力的高端技术人才，将外语教学目标 由原来的语言能力导向转变为职业能力导向，本套教材通过听、说、读、写、译等基本语言技能 训练，让学生完成不同行业领域的工作任务，将英语放到职场的背景中来学，放到员工的岗位职 责、工作流程中来学。 三、结构与内容紧扣行业领域的职场情境和核心业务 本套教材围绕行业核心概念和业务组织教学单元，不同单元相互关联，内容由浅入深、由易 到难，循序渐进；教材各单元主题契合行业典型工作场景，内容反映职业岗位核心业务知识与流 程。每本教材根据内容设置 8 至 10 个单元，用多种形式的语言训练任务提升学生对行业知识的理 解与应用。 序 i 四、资源立体多样，方便师生教与学 本套教材图文并茂。通过改编，在原版教材基础上每个单元增加了学习目标，明确了学生在完 成各单元学习后应该达到的知识和能力水平；增加了重点词汇中文注释和专业术语表，便于学生准 确理解行业核心概念；听力练习和阅读篇章均配有音频，并借助二维码扫码听音的形式呈现，实现 教材的立体化，方便学生学习；习题安排契合单元的主题内容，便于检测单元学习目标的实现 程度。教材另配有电子课件和习题答案，方便教师备课与授课。教师可以征订教材后联系出版社 索取。 本套教材共 10 本，包括《护理英语》《机电英语》《建筑工程英语》《运输与物流英语》 《烹饪、餐饮与接待英语》《旅游英语》《银行与金融英语》《市场营销与广告英语》《商务英语》 《商务会谈英语》，涵盖医药卫生、机电设备、土木建筑、交通运输、旅游、财经商贸等六大类专 业。建议高职院校结合本校人才培养目标，开设相应课程。 本套教材适合作为高职院校学生的行业英语教材，也适合相关行业从业人员作为培训或自学 教材。 姜宏 2021年3月31日 ii 机电英语 前言 本教材基于Sabrina Richards Sopranzi编写的Flash on English for Mechanics & Electronics（第二 版）主体内容，按照由简入繁、由易到难的原则，每个单元设计了导入、读、说、听、写、译六个 部分。此外，为了方便学生学习，每个单元配备了生词表和专业词汇表。 本教材主要内容包括机械学和电子学的基本知识和原理，以听、说、读、写、译等模块来训 练学生的英语技能，共10个单元。第1单元和第2单元主要介绍了材料、机械工程设计及机械工艺。 第3单元和第4单元主要介绍了电的基本概念、电能的产生、基本电工电路结构及其元件。第5单元 介绍了电子学基本概念和相关电子器件。第6单元介绍了电子学在电信和网络领域的重要应用。第7 单元介绍了计算机的发展历史和相关技术。第8单元主要涉及现代工业生产中非常重要的自动化技 术和机器人技术。第9单元主要描述了现代汽车的核心——发动机，及其基本结构和功能。第10单 元主要论述了机电设备维护的工艺规程和安全保护事项。 本教材适合高等职业院校机电一体化或相关专业的学生使用，也适合机电一体化专业领域的 工程技术人员使用。建议课时为32学时。 本教材由北京劳动保障职业学院王长全教授改编而成。在编写过程中得到了北京财贸职业学 院国际教育学院、清华大学出版社的大力支持和帮助，在此表示感谢。由于编者水平有限，书中难 免存在一定的疏漏和不足之处，欢迎广大读者批评指正！ 编者 2021年3月1日 前言 iii Contents Unit Topic Vocabulary Skills 1 Reading: properties of materials; basic metal processes; insulators and conductors Listening: descriptions of materials and metal processes Speaking: asking and answering questions about metal processes Writing: a summary of the main types of materials Materials and Properties . Types of materials: qualities, costs and properties . Metal processes . Mechanical, thermal, electrical-magnetic and chemical properties p. 2 2 . Technical drawing tools . Computer aided design system (CAD) . Computer aided manufacturing program (CAM); Machine tools: features and applications . Computer numerical control (CNC) machines Reading: the basic tools of the drafter; from manual drawing to computerised drawing; main features of machine tools; application of CNC machines to manufacturing processes Listening: description of CAD/CAM systems; automation of machine tools in manufacturing processes Speaking: discussion on CAD Writing: a summary of technical drawing and machine tools Technical Drawing and Machine Tools p. 18 . Basic atomic structure . Electricity and units of measurement . Conductivity of materials . Conventional power plants . Alternative power sources . Electrical distribution system Reading: the atomic structure; types of current; units of measurement of electric current; types of power plants; alternative power sources Listening: properties of conductors, semiconductors and insulators; different steps in the electrical distribution system Speaking: discussing the results of a quiz on energy saving Writing: the different stages in the distribution system; a summary of power sources and energy saving Electricity and Power 3 p. 34 . Circuit components . Types of electric circuits . Fuses and protective devices 4 Reading: description of the main circuit components; safety devices Listening: types of circuits Speaking: asking and answering questions about circuits Writing: describing the basic circuit components; explaining how to build a simple electric circuit Electric Circuits p. 48 5 Reading: short history of the main inventions in electronics; types of electronic circuits Listening: mobile phones and radio signals Speaking: discussing the difference between conventional eclectric circuit and integrated circuit Writing: describing the main advantages and disadvantages of an electronic device used every day . Main electronic inventions . Electronic circuits . Mobile phones and radio signals Electronics p. 56 机电英语 iv Vocabulary Skills Unit Topic 6 . Means of transmission . Ground and air transmission . Main network components . Network topologies Reading: ground and air transmission; network components Listening: network topologies Speaking: exchanging opinions on the use of everyday means of communication Writing: an article about the uses of computer networks Telecommunications and Networks p. 66 7 . Terms related to the history of computer . Computer components: hardware and software . USB flash drives . Types of computers . Internet connections Reading: a text about the computer evolution; about Steve Jobs; computer components; types of computers; different types of Internet connections Listening: USB flash drives Speaking: asking and answering questions about computer; talking about your own computer Writing: a summary of the Internet; a flow chart to introduce the computer development Computer: History and Technology p. 78 8 . Automation technologies . Robot applications . Sensors and transducers Reading: advantages and disadvantages of automation; applications of automation technologies; types of sensors Listening: robot applications; the optical mouse Speaking: discussing the impact of automation on your life Writing: describing automation technologies Automation and Robotics p. 92 9 . Types of engines . Types of fuel Reading: a text about the drive train; the four- stroke and the two-stroke engines; the diesel engine Listening: a mechanic talking about the differential; the ignition process Speaking: a short presentation about the engine Writing: a short paragraph about the four-stroke and the two-stroke engines Engines p. 102 10 . Preventive and corrective maintenance . Car components . Auto maintenance . Health and safety regulations and objectives . Safety signs and colours . Safety equipment . Fire safety plan Reading: types of maintenance; car maintenance tasks; safety and welfare in the UK; safety sign categories and meanings; safety equipment Listening: a dialogue between a mechanic and his customer; safety rules and accident procedures Speaking: a discussion about auto maintenance and safety measures Writing: a summary about safety rules when working Maintenance and Safety p. 116 Contents v Materials and Properties UNIT 1 Learning Objectives Upon completion of the unit, students will be able to: . identify the difference among various kinds of materials; . describe properties of different materials; . choose suitable materials for specific engineering applications. Starting Off What tools do you use in your life? Which materials are they made of? Please present some examples in your class. Reading 1 When a machine or a tool is made, the most suitable material must be chosen by considering its properties, which can be classified as mechanical, thermal, electrical and chemical. The main types of materials used in mechanical engineering are metals, polymer materials, ceramics and composite materials. The most commonly used materials are metals, which can be divided into ferrous and non- ferrous. They can be used in their pure form or mixed with other elements. In this second case we have an alloy and it is used to improve some properties of the metals. The most commonly used ferrous metals are iron and alloys which use iron. Because iron is soft and pasty, it is not suitable to be used as a structural material. Therefore, a small amount of carbon is added to it to make steel alloy. Non-ferrous metals contain little or no iron. The most common non-ferrous metals used in mechanics are copper, zinc, tin and aluminium. Some common non-ferrous alloys are brass (formed by mixing copper and zinc), bronze (formed by mixing copper and tin) and other aluminium alloys which are used in the aircraft industry. Other examples of materials used in mechanical engineering are plastic and rubber. PVC or polyvinyl chloride is a type of plastic and is used to insulate wires and cables. Rubber is a polymer and its best property is elasticity, as it returns to its original size and shape after deformation. Ceramic materials are good insulators: hard, resistant and strong, but brittle. Composite materials are made up of two or more materials combined to improve their mechanical properties. Concrete is reinforced with steel and is used in building engineering. 1 What are these objects made of? Match the words in the box with the pictures. steel gold wood plastic glass ceramic 1) 2) 3) 5) 6) 4) 2 Read the text again and match the words and phrases with their definitions. 1) alloy a a type of plastic used for insulation 2) steel b a combination of different metals 3) PVC c an alloy formed by mixing iron and carbon 4) concrete d an alloy formed by mixing copper and zinc 5) brass e metals containing iron 6) ferrous materials f a composite material used to build houses 7) ceramic g a metal not suitable as structural material 8) iron h a good insulator but brittle 3 Read the text again and answer the questions. 1) What is the basic classification of metals? 2) What are the characteristics of iron? 3) Why are alloys created? 4) Which materials are good insulators? 5) Is steel an alloy? Which metal does it contain? 4 Complete the following diagram. MATERIALS polymer materials plastic concrete ferrous non-ferrous alloy Reading 2 Mechanical properties Strength The most common mechanical property is strength, or the ability of a material to resist forces without breaking, bending, shattering or changing in any permanent way. For example: if elastic material is stretched, the change will be temporary; but it will be permanent with plastic or metal materials. When a force is applied to a material, as when a weight is put on the end of a rope, certain forces inside the rope cause it to stretch. In mechanics, the weight that is applied is called the load. The force within the rope that causes it to stretch is called the stress. The actual change, in this case the stretching, is called the strain. A material can undergo three changes due to stress. It can stretch, it can get shorter, or it may divide into layers. The stress that causes a material to stretch is called tensile stress. The stress that causes a material to get shorter is called compressive stress, while the stress that causes a material to divide into layers is called shearing stress. STRENGTH OF MATERIALS (in pounds per square inch) Material Tensile Compressive Shearing Aluminium 58,000 35,000 35,000 Brick 1,500 – 3,000 Bronze 85,000 Cast iron 60,000 145,000 70,000 Concrete 2,000 Copper 50,000 – 70,000 Stone 8,000 Wrought iron 48,000 25,000 38,000 Plasticity This is the ability of a material to be permanently changed in shape. For example, the plasticity of molten aluminium can be demonstrated by pouring it into a mould. Once the aluminium has cooled down, it can be removed from the mould and has a new shape. Malleability, which occurs when metals are hammered or rolled into thin sheets, is also a property associated with plasticity. Gold, for example, is one of the most malleable metals. Other common metals in order of malleability are silver, copper, aluminium, tin, zinc, and lead. Ductility This is the ability of certain solid substances to undergo permanent changes in shape without breaking usually by stretching the length. For example, a piece of copper can be stretched to make a thin wire, but the shape of a brick cannot be permanently changed except by breaking it. Ductility is a valuable property of many metals including aluminium, gold, iron, nickel, and silver. The term malleability is often used in place of ductility when describing the property of metals that allows them to be hammered into thin sheets. Elasticity This is the ability of a substance to return to its original shape or volume after it has been changed by a force. All substances have some elasticity. Some familiar uses of elasticity are the springs in vehicles and the rubber and air in balls. Hardness This is the resistance of a material to surface abrasion, scratching and indentation. The standard scale of hardness is as follows: soapstone, gypsum, chalk, fluorite, apatite, porcelain, quartz, topaz, corundum, diamond. Brittleness This is the property of a material that is hard but easily broken. Fatigue This is the ability to resist repeated stress cycles and tension. 5 Read the text and decide if the statements are true (T) or false (F). T F　　　　 1) The ability of a material to resist forces is the most common mechanical property. 　　　　 2) Strain means the weight applied to a material. 　　　　 3) A material doesn’t undergo any changes when under stress. 　　　　 4) Shearing is the stress that divides materials into layers. 　　　　 5) Aluminium is less tensile than bronze, but more than brick. 　　　　 6) Cast iron is as compressive as concrete. 　　　　 7) The ability of metals to be hammered or rolled into thin sheets is called plasticity. 　　　　 8) Diamond is the hardest and chalk is the softest. 　　　　 6 Match the words with their definitions. 1) brittleness a the state of a material which is distorted by forces acting on it 2) strain b resistance to cutting, indentation, abrasion 3) plasticity c the tendency to fracture without appreciable deformation and under low stress 4) hardness d a property of certain materials by which deformation due to a stress is largely retained after removal of the stress Reading 3 Thermal properties Thermal properties describe how a material behaves when its temperature changes. Thermal conductivity, thermal expansion and melting point are among the main thermal properties. Thermal conductivity In physics, thermal conductivity is the ability of a material to conduct heat. Metals in general have high thermal conductivity, as they are able to transmit heat energy. Thermal conductivity is important in materials science, research, electronics, building insulation and related fields, especially when high operating temperatures are achieved. Cooling solutions for electronics or turbines usually use high-thermal conductivity materials such as copper, aluminium, and silver to cool down specific elements. However, applications in buildings or furnaces use low thermal conductive materials such as polystyrene and alumina for insulation purposes. Thermal expansion This is the change in dimensions that occurs with most materials as the temperature is increased or decreased. Heat causes expansion because it increases the vibrations of atoms or molecules in a material. Different materials expand by different amounts when the temperature is raised by one degree. For example: aluminium expands twice as much as iron under the same temperature increase. Melting point The temperature at which a material turns suddenly from solid to liquid. For metals the maximum operating temperature is usually around two thirds of the melting temperature. 7 Read the text and answer the questions about thermal properties. 1) What is heat energy? 2) Which are main conductors of energy? 3) How is energy transferred? Unit 1 Materials and Properties 9 Reading 4 Electrical-magnetic and chemical properties Electrical conductivity This is the ability of a material to conduct electrical charge. All materials conduct electricity, but some materials such as rubber and glass allow so few electrons to get through that the current is hardly noticeable. These materials are called insulators. Other materials, such as metals, conduct current readily. These materials are called conductors. Metal, in general, is the best conductor, and silver, copper, gold, and aluminium are among the best metallic conductors. Electrical resistivity This is the ability of a material to resist, or oppose, the transport of electrical charge in response to an external electrical field. A chemical property is any of the properties of a material that become evident during a chemical reaction. Chemical properties can be useful to identify an unknown substance or to purify it or separate it from other substances. Resistance to chemicals This is the ability of a material to resist chemical attack and to withstand corrosion processes such as oxidation. Atomic volume This is the volume occupied by a gram-atom of an element in the solid state. Density This is the mass of material per unit volume (kg/m3). 8 Read the text and find the following information. . difference between insulators and conductors; . best electrical conductors; . properties useful to identify unknown substances; . one of the chemical properties. MY GLOSSARY thermal adj. 热的，热量的 composite adj. 复合的，合成的 ferrous adj. 亚铁的，含铁的 alloy n. 合金 carbon n. 碳；复写本 steel n. 钢 copper n. 铜；红棕色，紫铜色 zinc n. 锌 tin n. 锡 aluminium n. 铝 brass n. 黄铜 bronze n. 青铜；古铜色 plastic n. 塑料；塑料制造（业） rubber n. 橡胶；合成橡胶 insulate v. 使隔热；使隔音；使绝缘 wire n. 金属丝，金属线 cable n. （传输电、电话信号等 的）电缆；（电视节目或电 话信号的）有线传输系统 elasticity n. 弹性；弹力 deformation n. 形变，变形 brittle adj. 易碎的，脆的；不友好的 concrete n. 混凝土 shatter v. 粉碎，破坏 stretch v. 伸出；伸长；拉伸 strain n. 张力；拉紧 layer n. 层；涂层 tensile adj. 可拉长的，有伸展性的 shear v. （尤指金属部件因剪切 力）折断，断裂 brick n. 砖 cast iron 生铁 wrought iron 熟铁 plasticity n. 可塑性 mould n. 模子，模具；铸模 malleability n. 延展性 hammer v. 捶击，反复敲打 sheet n. （尤指长方形的）大薄 片；床单 ductility n. 延展性；可塑性；黏性 abrasion n. 磨损；擦伤 indentation n. 压痕，凹陷 hardness n. 硬度；困难；严厉 fatigue n. 疲劳，疲惫，劳累 conductivity n. 传导性；电导率 expansion n. 扩大，增加，扩展 melting point 熔点 turbine n. 涡轮机，汽轮机 furnace n. 熔炉，火炉 atom n. 原子 molecule n. 分子 noticeable adj. 显著的，显而易见的 resistivity n. 电阻率 withstand v. 经受，抵挡 corrosion n. 腐蚀，侵蚀 oxidation n. 氧化 density n. 密度 Listening 9 Listen and complete the definitions with the words in box. cooking coins alloy air copper wires steel carbon gold ferrum expensive ductile Iron: Its Latin name is (1) ferrum . It is magnetic and has a silvery colour. In prehistoric times it was used to make ornaments and weapons. If exposed to the (2) , it oxidises. (3) : It is one of the most widely used metals by humans. In prehistoric times it was used to make cooking utensils, (4) and ornamental objects. It is used in (5) and cables. (6) : It is the most (7) metal and is used to create precious jewellery. It is the most (8) metal. (9) : It is an (10) formed from iron and (11) . It can contain between 2.1% and 4% carbon. It is also used for (12) utensils and pans. 10 Listen and complete the texts about the different processes metals can go through. Casting is a 6,000 year old process. It is the oldest and most well-known technique based on three fundamental steps: moulding, melting and (1) . First the pattern is made to form the mould. Then an empty mould is created, and finally the empty cavity is filled with molten metal which is then left to solidify into the shape. Casting materials are usually (2) but can also be plastic, resin or various cold materials for example (3) . Casting is usually used for making complex shapes. Drawing is a manufacturing process for producing wires, bars and (4) by pulling on material through a series of dies until it increases in length. It is divided into two types: sheet metal drawing, and wire, (5) , and tube drawing. Drawing is usually done at room temperature, but it can be performed at elevated temperatures to hot work large wires, rods or hollow sections in order to reduce forces. Forging is the process by which metal is heated and shaped by a compressive force using a hammer or a press. It is used to produce large quantities of identical parts, such as (6) parts in the automobile industry. Cold forging is done at a low temperature using (7) metals and plastic. Hot forging is done at a high temperature and makes metal easier to shape without breaking. In the past, forging was done by a blacksmith using a hammer. Nowadays industrial forging is done with (8) powered by a machine. Rolling is a metal forming (9) in which a material (metal, plastic, paper or glass) is passed through a pair of rollers. According to the (10) of material rolled, there is hot rolling or cold rolling. Extrusion is a process used to produce objects with a fixed cross- sectional profile. A material is pushed or drawn through a die of the desired cross-section. The two main (11) of this process are its ability to create very complex cross-sections and work materials that are brittle. The extrusion process can be done with hot or cold materials. Commonly extruded materials include metals, polymers, (12) , concrete and foodstuffs. Ceramic can also be formed into shapes via extrusion. Terracotta extrusion is used to produce pipes. Many modern bricks are also manufactured using a brick extrusion process. Extrusion is also used in (13) processing. Products such as certain pastas, many breakfast cereals, French fries, dry pet food and ready-to-eat snacks are mostly manufactured by extrusion. Sheet metal forming is simply metal formed into thin and flat pieces. The basic forms can be cut and bent into a variety of different shapes. Everyday objects are constructed with this process. There are many different metals that can be made into sheet metal, such as aluminium, (14) , copper, steel, tin, nickel and titanium. For decorative uses, important sheet metals include silver, gold, and platinum. Sheet metal forming is used in car bodies, airplane wings and roofs for (15) . Speaking 11 Take turns with your partner asking and answering the following questions. 1) Which steps are included in casting? 2) What is the mould used for? 3) What does drawing use in order to process metals? 4) What types of drawing are there? 5) What kind of process is forging? 6) How was forging done in the past? 7) What does rolling consist of? 8) What materials can be used in rolling? 9) What are the advantages of extrusion? 10) What materials can be used in extrusion? 11) What kind of process is sheet metal forming? 12) What can vary in sheet metal forming? Writing 12 Write a summary of the texts in Reading 1 and Exercise 9 following the flow chart. Write about the importance in engineering of having a specific knowledge of materials. List the materials and the main groups used in mechanics. Tell the difference between ferrous and non-ferrous metals. Say what an alloy is and why it is used. Write a list of non-ferrous metals and alloys. 13 Complete the text about insulators and conductors with the words from the box. heat wire conductors insulators thermal material hot dangerous electricity copper Some materials let heat pass or flow through easily and these are called (1) _________________ conductors. Other materials don’t let (2) _________________ pass or flow through them and these are called thermal insulators. Among the best (3) _________________ are carbon and most metals (especially silver and copper). Think about metal saucepans; they allow the heat from the cooker to pass through easily to heat up the water and food inside them. The best (4) _________________ include wood, cork, concrete, plastic and fabrics such as thermal vests and oven gloves. If a(n) (5) _________________ is a good insulator then it’s a poor conductor. Heat only moves from (6) _________________ things to colder things. As well as conducting or insulating against heat, materials can also conduct or insulate against (7) _________________. As a general rule, materials that conduct heat well are also good conductors of electricity (e.g. metals such as copper, iron, steel and aluminium). Wood, plastic, glass and rubber are both thermal and electrical insulators. These are very important and have really essential uses. For example, (8) _________________ wires allow electricity to flow through them, but each (9) _________________ is covered in plastic and all are encased in plastic tubing so electricity won’t flow out and give you a shock; it’s insulated. Remember, electricity can be (10) _________________ . It can even be conducted through the sweat on your body! Translating 14 Translate the following sentences into Chinese. 1) The most commonly used materials are metals, which can be divided into ferrous and non- ferrous. ___________________________________________________________________________________________________ 2) Rubber is a polymer and its best property is elasticity, as it returns to its original size and shape after deformation. ___________________________________________________________________________________________________ 3) The most common mechanical property is strength, or the ability of a material to resist forces without breaking, bending, shattering or changing in any permanent way. ___________________________________________________________________________________________________ 4) This is the ability of a substance to return to its original shape or volume after it has been changed by a force. ___________________________________________________________________________________________________ 5) Melting point is the temperature at which a material turns suddenly from solid to liquid. ___________________________________________________________________________________________________ Technical Terms polymer n. a naturally occurring or synthetic compound consisting of large molecules made up of a linked series of repeated simple monomers 聚合物，聚合体 ceramic n. an artifact made of hard brittle material produced from nonmetallic minerals by firing at high temperatures 陶瓷制品；制陶艺术 polyvinyl chloride (abbreviation PVC) a type of plastic that is used especially for making clothes, floor coverings, and bags 聚氯乙烯 nickel n. (symbol Ni) a chemical element that is a silver-white metal used in making some types of steel and other alloys 镍 soapstone n. a soft stone having a soapy feel and composed essentially of talc, chlorite and often some magnetite 皂石 gypsum n. a common white or colourless mineral used to make cements and plasters (especially plaster of Paris) 石膏 fluorite n. a soft mineral (calcium fluoride) that is fluorescent in ultraviolet light 氟石 apatite n. a common complex mineral consisting of calcium fluoride phosphate or calcium chloride phosphate 磷灰石 porcelain n. a hard but delicate, shiny, white substance made by heating a special type of clay to a high temperature, used to make cups, plates, decorations, etc. 瓷 quartz n. a hard, transparent mineral substance, used in making electronic equipment and accurate watches and clocks 石英 topaz n. a transparent, yellow stone used in jewellery 黄玉，黄宝石 corundum n. a compound of silicon and carbon that is used as an abrasive (= a substance for rubbing away surfaces) 金刚砂，碳化硅 diamond n. a transparent, extremely hard precious stone that is used in jewellery, and in industry for cutting hard things 钻石，金刚石 polystyrene n. a very light soft plastic that is usually white, used especially for making containers that prevent heat loss 聚苯乙烯 alumina n. a white substance found in many types of rock, especially clay 矾土 gram-atom n. the quantity of an element whose weight in grams is numerically equal to the atomic weight of the element 克原子 Technical Drawing and Machine Tools UNIT 2 Learning Objectives Upon completion of the unit, students will be able to: . have basic knowledge of technical drawing; . understand the process from technical drawing to product; . take creative methods into consideration when producing drawn parts. Starting Off Technical drawing is important for engineers. Its purpose is to describe or explain all the characteristics of a product, giving all the necessary information that will help a manufacturer to produce that component. Let’s learn the text to understand technical drawing and have a good grasp of the methods to produce drawn parts. Reading 1 Technical drawing, also known as drafting, is the act and discipline of composing plans. The main purpose of technical drawing is to describe or explain all the characteristics of a product, giving all the necessary information that will help a manufacturer to produce that component. The visual image should be accurate in terms of dimensions and proportions, and should provide an overall impression of what an object is or does. It is a precise task requiring a high level of skill and suitable engineering tools. A drafter is the person who makes a drawing and who requires a wide knowledge of geometry, trigonometry and spatial comprehension, and in all cases must be precise and accurate and give great attention to detail. People who communicate with technical drawings use a visual language and technical standards that define practical symbols, perspectives and units of measurement. What are the tools and instruments used by a drafter in manual drafting? A T-square, a protractor, a compass, rulers, and triangles. Paper is also important and can be divided into layout paper, which is thin and fragile, and cartridge paper, which is heavier and more suitable for final drawings. Pencils used in drawing are graded from H to F depending on the hardness. The final drawing is made using a technical pen, graded according to the point, which must maintain the same line width. They are used with a range of stencils to add symbols, letters and patterns to the drawing. Rubbers remove pencils or pen writing when mistakes are found. Correction fluid is used to mask text errors. 1 Read the text about technical drawing and label the pictures. 4) 5) 1) 2) 6) 3) 2 Read the text again and choose the correct answer. 1) Technical drawing is needed to _______________. A make a scale of the product B practise pens, rulers and stencils C let the manufacturer understand the requirements 2) The drafter needs _______________. A some paper and a pencil B a wide range of technical instruments C the final product 3) Paper is chosen considering _______________. A what sort of drawing the drafter is going to make B the pencils the drafter is going to use C the drafter’s preference 4) Pencils are graded according to _______________. A　hardness B hardness and colour C hardness and point 5) A technical pen _______________. A makes regular lines B maintains the same line width C draws lines of the same length 6) When mistakes are found _______________. A we can’t correct them B they’re removed with correction fluid C stencils can cover them Reading 2 A machine tool uses a power source to modify the shape of metal components of machines. It is a sort of machine used as a tool in the making of other machines. Machine tools were powered in the Middle Ages by humans and animals, and later by the energy captured by waterwheels. After the Industrial Revolution, most machine tools were powered by steam engine and nowadays by electricity. Machine tools can be operated manually, or under automatic control. In the 1960s, computers gave more flexibility to the process. Such machines became known as computer numerical control (CNC) machines. They could precisely repeat sequences, and could produce much more complex pieces than even the most skilled tool operators. Let’s examine the main features of some of the most commonly used machine tools. Turning machine The engine lathe is the most important of all the machine tools. It is used to produce external or internal cylindrical surfaces. The piece is held by the machine and is rotated while a cutting tool removes excess metal from the external diameter. Internal turning consists of enlarging and finishing a hole. Shaper This is a metal-cutting machine used to produce or modify flat surfaces. The cutting tool moves cutting on the forward stroke, with the piece feeding automatically towards the tool during each return stroke. Shapers can be horizontal or vertical. Drilling machine It is used to produce circular holes in metal with a twist drill. It also uses a variety of other cutting tools to perform the basic hole-machining operations. Milling machine This cuts flat metal surfaces. The piece is fed against a rotating cutting tool. Cutters of many shapes and sizes are available for a wide variety of milling operations. Milling machines may be manually operated, mechanically automated, or digitally automated via computer numerical control (CNC). Grinding machine This removes excessive material from parts that are brought into contact with a rotating abrasive wheel. Grinding is the most accurate of all the basic machining processes, but also the most time consuming. Band saw It is a power tool which uses a blade consisting of a continuous band of metal with teeth along one edge. The band usually rides on two wheels rotating in the same plane. Band saws are used for woodworking, metalworking, or for cutting a variety of other materials, and are particularly useful for cutting irregular or curved shapes. A constant flow of liquid is poured over the blade to keep it cool and preventing it from overheating. Press This is a machine tool that changes the shape of a workpiece. Historically, metal was shaped by hand using a hammer. Machine presses can be dangerous. Bi-manual controls (controls which require both hands to be on the buttons to operate) are a very good way to prevent accidents. 3 Read the texts in Reading 2 about machine tools and complete the table. Machine tool Final result Description turning machine external and internal flat surface It removes excess metal from the external diameter. It enlarges and finishes a hole. specific shape It cuts flat metal surfaces. holes It uses a twist drill to make holes. flat surface It cuts the piece. specific shape It changes the shape of a workpiece. cut pieces It cuts various parts using a continuous band of metal with teeth. finishing It removes excessive material from parts. 4 Read the texts again and decide if the following sentences are true (T) or false (F). T F　　　　 1) Turning machines remove excess metal from the external diameter and enlarge and finish a hole. 　　　　 2) Shapers can only be vertical. 　　　　 3) Drilling machines use a twist drill to make circular holes. 　　　　 4) Milling machines can only be manually operated. 　　　　 5) Grinding machines remove excessive material from parts. 　　　　 6) Band saws use a band of metal with teeth to cut various parts. 　　　　 7) Presses are not dangerous if operated by both hands. 　　　　 Unit 2 Technical Drawing and Machine Tools 25 Reading 3 The lathe An example of a machine tool is the lathe, which is a turning machine. Turning, one of the most important operations in a machine shop, is a form of material removal process, which is used to create rotational parts by cutting away unwanted material. Usually, the term turning is reserved for the generation of external surfaces by this cutting action, whereas when this same essential cutting action is applied to internal surfaces (that is, holes of one kind or another) it is called boring. The starting material is generally a workpiece generated by other processes such as casting, forging and extrusion. Turning can be done manually, in a traditional form of lathe, which frequently requires continuous supervision by the operator, or by using an automated lathe which does not. Today, the most common type of such automation is computer numerical control, better known as CNC, which is also commonly used with many other types of machining besides turning. A lathe rotates the workpiece on its axis to perform various operations. It generally has a stand which sits on the floor and elevates the lathe bed to a working height. Small lathes sit on a workbench, and do not have a stand. Almost every lathe has a bed, which is a horizontal beam. At one end of the bed there is a headstock which contains high-precision spinning bearings. Within the bearings there is a rotating horizontal axle, with an axis parallel to the bed, called the spindle. Spindles are powered, and impart motion to the workpiece. The spindle is driven, either by foot power or by a belt and gear drive, to a power source. In most modern lathes this power source is an integral electric motor. The counterpoint to the headstock is the tailstock, also referred to as the loose head because it can be positioned at any convenient point on the bed by undoing a locking nut, sliding it along the required area and then locking it again. 5 Read the text and look at the picture of the lathe. Then complete the text with missing words. Spindle Tool rest Tailstock Headstock Lock knob Bed The horizontal beam is called (1) __________. At one end of the bed is the (2) __________ which contains high-precision spinning bearings. Rotating within the bearings there is the (3) __________. The counterpoint to the (4) __________ is the (5) __________ which contains a barrel which does not rotate, but can slide in and out. Between the (6) __________ and the (7) __________ there is a toolpost, at the top of which there is a horizontal (8) __________. 6 Read the text again and match the two parts of the sentences. 1) The turning process is mainly used a a form of material removal process. 2) A headstock is placed b the counterpoint to the headstock. 3) The tailstock, or loose head, is c at one end of the bed. 4) The spindle rotates within d the bearings with a horizontal axe. 5) Turning is e to shape round pieces of metal. MY GLOSSARY technical drawing 技术制图 drafting n. 起草；制图 T-square n. （画图用的）丁字尺，曲 尺 protractor n. 量角器，分 度规 ruler n. 直尺 triangle n. 三角形 fragile adj. 脆的，易碎的 cartridge paper 画图纸 width n. 宽度，广度 stencil n. （印文字或图案用的） 模板；（用模板印的）文 字或图案 fluid n. 液体，流体 machine tool （用于生产或维修的） 工具，器具 waterwheel n. （为机械提供动力的） 水轮，水车 steam engine 蒸汽机 skilled adj. 有技能的；熟练的，有 经验的；巧妙的 feature n. 特色，特征，特点 turning machine 车床 lathe n. 车床，旋床 cylindrical adj. 圆柱形的 diameter n. 直径 shaper n. 牛头刨床 stroke n. 打击；（时钟等）鸣， 敲；笔画；手段；成就； 抚摩 drilling machine 钻床 milling machine 铣床 grinding machine 磨床 excessive adj. 过度的；过分的 abrasive adj. 有研磨作用的；粗糙的 band saw 带锯 blade n. 刀片；刀刃 curved adj. 呈弯曲状的，弧形的 overheat v. （使）过热，（使）变得 过热 press n. 压力机，挤压机；印刷 机 boring n. 钻孔 forge v. 锻造 extrusion n. 挤压 supervision n. 监视，监督 axis n. 轴 stand n. 支架，座 workbench n. 工作台 axle n. 车轴，轮轴 impart v. 赋予，给予 motor n. 发动机，马达 counterpoint n. 对应物 undo v. 解开，打开 Listening 7 Listen and complete the text with the words in the box. creation advantages boards drawings software defects faster instructions traditional reduce modification electronically CAD/CAM systems Drawing (1) and manual drawing are not always precise and rapid: (2) design is usually slow, especially in its revision and (3) . For this reason manufacturing firms have replaced manual drawing with computer-aided design (CAD) to carry out functions related to design and production. This computer technology assists the designer in the (4) , modification and analysis of a physical object. Nowadays computer (5) can easily provide a three-dimensional drawing, which allows engineering designers to see how mechanical components may fit together without making models thus saving a lot of time. CAD is much (6) and more accurate than manual drawing; designs can be quickly modified, reproduced and transmitted (7) . Computer simulated analysis of the model helps experts find problems and (8) without building prototypes, in this way saving a lot of money and time. When the design is ready, the CAD system can generate the detailed (9) needed to start product manufacturing. When CAD systems are linked to manufacturing equipment controlled by computers, they form an integrated CAD/CAM system. Computer-aided manufacturing (CAM) offers significant (10) over traditional approaches by controlling manufacturing equipment with computers instead of human labour. CAM converts the design of a component into computer language and it gives (11) to the computer regarding machine operations. Thanks to CAD/CAM systems it is possible to eliminate operator errors and (12) manufacturing costs. 8 Read the text about CNC. Then Listen to the sentences and put them in the correct order. Computer numerical control (CNC) refers to the automation of machine tools in manufacturing processes. The machines are controlled by computer software which carries out a series of operations automatically. The first NC machines were built in the 1940s and 1950s. They are used to cut and shape products, such as automobile parts that need precise specifications. Parts must be carefully planned and prepared by CNC programmers. First they view the three-dimensional computer aided designed part. Then they calculate where to cut, the speed and shape and select the tools and materials. The CNC programmers translate the planned machine operations into a set of instructions. These instructions are translated into a computer aided manufacturing (CAM) program containing a set of commands for the machine. The commands are a series of numbers which explains where to cut and the position of material. The computer checks all the operations made by the machine tools. a The planned machine operations are translated into a set of instructions. b These instructions are translated into a CAM program. c The program contains a set of commands for the machine. d It is calculated where to cut and tools and materials are selected. e The computer checks all the operations made by the machine tools. f Programmers view the part in its three-dimensional computer aided design. Speaking 9 Discuss the following questions and practice them with each other. 1) What is required for a precise technical drawing? 2) Manufacturing firms have replaced manual drawing with computer-aided design (CAD) to carry out functions related to designing and production. Why does this happen? Writing 10 Write down the Chinese definitions of the following words and phrases. 1) surface ______________________________________ 2) hole _________________________________________ 3) spindle ______________________________________ 4) lathe bed ____________________________________ 5) headstock ____________________________________ 6) tailstock _____________________________________ 7) saddle _______________________________________ 8) boring _______________________________________ 9) casting ______________________________________ 10) forging _______________________________________ 11 Write a summary of the texts about technical drawing and machine tools in the Reading part, and then draw a flow chart between technical drawing and machining processes. Unit 2 Technical Drawing and Machine Tools 31 Translating 12 Translate the following sentences into Chinese. 1) The visual image should be accurate in terms of dimensions and proportions, and should provide an overall impression of what an object is or does. ___________________________________________________________________________________________________ 2) Milling machines may be manually operated, mechanically automated, or digitally automated via computer numerical control (CNC). ___________________________________________________________________________________________________ 3) Computer numerical control (CNC) refers to the automation of machine tools in manufacturing processes. The machines are controlled by computer software which carries out a series of operations automatically. ___________________________________________________________________________________________________ 4) Today, the most common type of such automation is computer numerical control, better known as CNC, which is also commonly used with many other types of machining besides turning. ___________________________________________________________________________________________________ 5) The counterpoint to the headstock is the tailstock, also referred to as the loose head because it can be positioned at any convenient point on the bed by undoing a locking nut, sliding it along the required area and then locking it again. ___________________________________________________________________________________________________ Technical Terms geometry n. the area of mathematics relating to the study of space and the relationships between points, lines, curves, and surfaces 几何学 trigonometry n. a type of mathematics that deals with the relationship between the angles and sides of triangles, used in measuring the height of buildings, mountains, etc. （数学中的）三角学 beam n. a long piece of wood, metal, etc. used to support weight, especially as part of the roof in a building 梁 headstock n. the stationary support in a machine or power tool that supports and drives a revolving part 头座；主轴箱 bearing n. a part of a machine that supports a moving part, especially one that is turning 轴承 gear n. a device, often consisting of connecting sets of wheels with teeth (= points) around the edge, that controls how much power from an engine goes to the moving parts of a machine 排挡；传动装置 tailstock n. support consisting of the movable part of a lathe that slides along the bed in alignment with the headstock and is locked into position to support the free end of the workpiece （车床的可调整或可滑动的）尾座 spindle n. a part of a machine around which something turns, or a rod onto which thread is twisted when it is spun (= made by twisting) （机器的）轴；纺锤，绕线杆 Unit 2 Technical Drawing and Machine Tools 33 Electricity and Power UNIT 3 Learning Objectives Upon completion of the unit, students will be able to: . understand the electricity and current; . have knowledge of electric circuits and electric energy generation; . take energy saving into consideration when using electricity. Starting Off Electricity is used in many places. Can you give some circumstances in which electricity is used? Do you know what electricity is and where electricity comes from? How energy is generated? Reading 1 All substances, solids, liquids or gases, are composed of one or more of the chemical elements. Each element is composed of identical atoms. Each atom is composed of a small central nucleus consisting of protons and neutrons around which orbit shells of electrons. These electrons are very much smaller than protons and neutrons. The electrons in the outermost shell are called valence electrons and the electrical properties of the substance depend on the number of these electrons. Neutrons have no electric charge, but protons have a positive charge while electrons have a negative charge. In some substances, usually metals, the valence electrons are free to move from one atom to another and this is what constitutes an electric current. 1 Label the picture with the name of each part. 1) 2) 3) 2 Read the text again and complete the sentences with the missing information. 1) Elements make up ___________________________________________________________________________. 2) Identical atoms ______________________________________________________________________________. 3) Atoms consist of _____________, _____________and _____________________________________________. 4) Inside there are __________ and __________, while outside _____________________________________. 5) Shells_________________________________________________________________________________________. 6) Valence electrons ____________________________________________________________________________. 7) Neutrons do not have ________________________________________________________________________. 8) Electricity is generated when _________________________________________________________________. Reading 2 There are two types of current: direct current (DC) and alternating current (AC). Direct current is a continuous flow of electrons in one direction and it never changes its direction until the power is stopped or switched off. Alternating current constantly changes its direction because of the way it is generated. The term “frequency” is used to indicate how many times the current changes its direction in one second. Alternating current has a great advantage over direct current because it can be transmitted over very long distances through small wires, by making energy high voltage and low current. There are several quantities that are important when we are talking about electric current. Volts (V)—so named after the Italian physicist Alessandro Volta—measure the difference of electric potential between two points on a conducting wire. Amperes (A) measure the amount of current flowing through a conductor, that is to say the number of electrons passing a point in a conductor in one second. Coulomb (C) measure the quantity of charge transferred in one second by a steady current of one ampere. Power is the rate at which work is performed and it is measured in watts (W). A Kilowatt (kW), which is equal to one thousand watts, is used to measure the amount of used or available energy. The amount of electrical energy consumed in one hour at the constant rate of one kilowatt is called kilowatt- hour. 3 Read the text and complete the table with the missing information. Unit of measurement What does it measure? (1) ____________________ the number of electrons passing a given point in a conductor in one second (2) ____________________ the quantity of electricity transferred by a steady current of one ampere (3) ____________________ the amount of electric energy used (4) ____________________ the difference of potential between two points on a conductor (5) ____________________ rate at which work is done Reading 3 Conventional power plants 1 Nuclear power plants About 10% of the world’s electric power is produced by nuclear power plants. Nuclear power requires little fuel and causes much less air pollution than other power plants, but it can cause severe health and environmental problems when accidents occur, with a consequent release of radioactive material. This type of energy is produced by the splitting of atoms of uranium, which releases heat. This process—called fission—produces large amounts of steam, which is used to turn the blades of turbines thus creating energy. The main problems with nuclear power are linked to the location of the power plants, as people are not willing to have these plants near their homes, and the disposal of waste material, which stays radioactive for centuries. 2 Thermoelectric power plants They provide about 2/3 of the world’s electricity. These plants burn fossil fuels, such as coal, oil or natural gas, which are all non-renewable resources. This means that in the future there will be a limited supply of these resources. The main advantage of thermoelectric power plants is that they are reliable and can meet the demand in peak periods. Electricity is generated by heating water in a C A B boiler to create steam, which is then pressurised and used to turn the blades of giant turbines that produce electricity. These power plants cause environmental pollution because of the combustion of fossil fuels which release carbon dioxide. 3 Hydroelectric power plants The energy produced by water can be captured and turned into electricity. The use of a dam on a river allows hydroelectric power plants to store water in an artificial lake, or reservoir. When released, the force of the water spins the blades of giant turbines, which are connected to a generator producing energy. Hydropower is one of the most important renewable energy resources, because it is reliable, efficient and does not pollute the air. Although it has high initial costs, it is cheap to operate. Unfortunately, it has a great impact on the environment, as humans, animals and plants may lose their natural habitats. 4 Have you ever wondered where the electricity in your house comes from? Read the texts about the different types of power plants and match them with the pictures. 5 Read the texts again and decide if the following sentences are true (T) or false (F), and then correct the false ones. T F　　　　 1) Nuclear power plants do not produce air pollution at all. 　　　　 2) Accidents in nuclear power plants can have terrible consequences for the environment. 　　　　 3) Nuclear power plants produce biodegradable waste material. 　　　　 4) Thermoelectric power is generated by the combustion of renewable resources. 　　　　 5) Thermoelectric power plants are environmentally friendly. 　　　　 6) Dams are built on rivers to store water. 　　　　 7) The water released from the reservoir flows through the generator. 　　　　 8) The only disadvantage of hydropower is its high initial cost. 　　　　 Unit 3 Electricity and Power 39 Reading 4 Alternative power sources Environmental problems such as the greenhouse effect and air pollution have led scientists to find alternative power sources which are renewable and less polluting. Solar energy Sunlight can be directly converted into electricity by solar cells made of silicon. When light strikes the cells, a part of it is absorbed by the semiconductor material. The energy of the absorbed light knocks electrons loose, allowing them to flow freely and produce electricity. The process of converting light (photons) into electricity (voltage) is known as the photo-voltaic process (PV). Solar cells are usually combined into panels and grouped into arrays. Even if the initial costs can be high, the PV system provides an independent, reliable electrical power source. It can produce energy for more than 15 years and its routine maintenance is simple and cheap. Wind energy Wind energy is one of the cheapest renewable technologies available today. The wind turns the blades of giant turbines, producing in this way kinetic energy which is then converted into mechanical power and electricity by a generator. The main disadvantage of wind energy is that there are few suitable wind sites where it is possible to have a constant production of electricity. Tidal energy This alternative power source, which is typically used in coastal areas, turns the potential energy of tides into electricity. Tidal power generators use rising and falling tides in much the same manner as hydroelectric power plants. Large underwater turbines are placed in areas with high tidal movements and are designed to capture the kinetic energy of rising and falling tides. The turbines are driven by the power of the sea both when the tide comes in and when it goes out. The problem with tidal power is that only massive increases in tides can produce energy and there are very few places where this occurs. Moreover, the aquatic ecosystem and the shoreline can be damaged by the changes in the tidal flow. Geothermal energy In the past, people used hot springs for bathing, cooking and heating. Geothermal energy is based on the fact that the Earth is hotter below the surface. The hot water which is stored in the Earth can be brought to the surface and used to drive turbines to produce electricity or it can be piped through houses as heat. This energy is cheap and has a low impact on the environment, but there are few sites where it can be extracted at low cost. Biomass energy Biomass is a renewable energy source deriving from plant material and animal waste. When it is burnt, it releases its chemical energy as heat. Biomass fuels include forest residues (such as dead trees, branches and tree stumps), straw, manure and even municipal solid waste. Biomass energy is a natural process. It is carbon neutral and has low initial costs. It used to be the main source of heating at home in the past and it continues to be highly exploited in the developing world. The main disadvantage of biomass is that it has a smaller potential than other energy sources and requires excellent maintenance skills. 6 Complete the table with the missing information. 7 Match the words and phrases with their definitions. 1) array a a spot where hot water comes up naturally from the ground 2) kinetic b unwanted material left after using 3) tide c a group of things arranged in a particular way 4) hot spring d waste material from animals used as fertiliser 5) pipe e the process of keeping something in good condition by regularly checking it 6) manure f produced by motion 7) waste g to send a liquid or a gas through a tube 8) maintenance h the regular change in the level of the sea caused by gravitational attraction of the moon and the sun Type of energy How it works Advantages Disadvantages high initial costs Wind energy It is a natural process because it exploits the potential energy of tides. MY GLOSSARY identical adj. 完全相同的 orbit v. 进入轨道 shell n. 壳；框架，骨架 valence n. 价，原子价，化合价 charge n. 电荷 current n. （水、气、电）流 switch off 关掉；不再关注，不再 理睬 name after 以……命名 steady adj. 稳步的；持续的；有规 律的 power plants 发电站 fuel n. 燃料；燃烧剂 pollution n. 污染 release n. & v. 释放，放走；放开，松开 radioactive adj. 放射性的，有辐射的 split v. 分裂，裂开 waste v. 浪费，滥用 renewable adj. （能源）可再生的 reliable adj. 可信赖的，可靠的；真 实可信的 boiler n. （尤指房子内供暖和 供应热水的）锅炉 combustion n. 燃烧，氧化 dam n. （尤指旨在蓄 水的）堤坝，水坝 reservoir n. 水库，蓄水池 greenhouse n. 温室，暖房 semiconductor n. 半导体 knock v. 碰，撞；敲门 array n. 一系列，一批，大量，大 群 maintenance n. 养护（保持道路、建筑、 机器设备等良好的工作 状态） kinetic energy 动能 tide n. 潮汐，潮水 aquatic adj. 水的；水生的 shoreline n. 海岸线，湖滨线，河岸线 hot spring 温泉 biomass n. 生物物质 straw n. 禾秆，麦秆，稻草 manure n. 粪肥（尤指马粪） municipal adj. 市政的，地方政府的 exploit v. 利用；开发，开采 Listening 8 Listen and complete the text with the missing information. Electricity consists of a (1) of free electrons along a conductor. To produce this current flow, a generator is placed at the end of the conductor in order to move the (2) . Conductors Electricity needs a material which allows a current to pass through easily, which offers little (3) to the flow and is full of free electrons. This material is called a conductor and can be in the form of a bar, tube or sheet. The most commonly used (4) are wires, available in many sizes and thicknesses. They are coated with insulating materials such as plastic. Semiconductors Semiconductors such as silicon and germanium are used in transistors and their conductivity is halfway in between a conductor and an (5) . Small quantities of other substances, called impurities, are introduced in the material to (6) the conductivity. Insulators A material which contains very (7) electrons is called an insulator. Glass, rubber, dry wood and (8) resist the flow of electric charge, and as such they are good insulating materials. 9 Listen to the text about the electrical distribution system and complete it with the words and phrases in the box. pole demand lower voltages consumers high-voltage power plants delivery appliances network transformer Electricity distribution is the final stage in the (1) of electricity to end users. In order to be able to use electric power for our daily activities, electricity must be transmitted from the (2) to other areas where it can be distributed to different (3) . The electricity generated by power plants is increased or stepped up at substations and distributed through (4) transmission lines, in order to minimize energy losses and to economise on the material needed for conductors. Transmission lines use voltages as high as 765,000 volts and they are usually connected in a (5) . This means that if a station receives an unexpected (6) for electric power, it can call on the other stations to help to meet the demand. Silver Copper Aluminium Iron Mercury Carbon Water Germanium Silicon Dry air Wood Glass Rubber Conductors Increasing Conducting Ability Semiconductors Insulators Then electrical power is converted from high voltage to (7) thanks to step-down transformers which turn electricity into different power levels. Once it is sent to your neighbourhood, another small (8) mounted on a (9) converts the power to even lower levels to be used at home. The final voltage is between 240 volts—for lights, TVs, and other smaller appliances—and 380 volts for larger (10) . Speaking 10 What is your opinion on energy saving? What do you and your family usually do to save energy? Take this test and discuss your answers in pairs. 1) I turn my desk lamp on only when it’s dark. Yes No 　　　　　　　 2) I try to open the fridge as little as possible. Yes No 　　　　　　　 3) I don’t use the lift to go down the stairs. Yes No 　　　　　　　 4) My parents take the bus to work instead of driving. Yes No 　　　　　　　 5) Our house temperature is below 20°C. Yes No 　　　　　　　 6) I always turn the light off when I leave a room. Yes No 　　　　　　　 7) I turn the TV off if I am not watching it. Yes No 　　　　　　　 8) We try not to use air conditioning unless it’s very hot. Yes No 　　　　　　　 9) We use rechargeable batteries. Yes No 　　　　　　　 10) We use energy-saving light bulbs. Yes No 　　　　　　　 Writing 11 Match the different stages in the distribution system to the numbers in the picture. a Transmission lines carry high-voltage electricity to different substations. b Electricity leaves the power plant. c Electricity is stepped down by transformers. d Current at lower voltages is transmitted to homes and offices. e The voltage is increased at a step-up station. f Power levels are lowered by small transformers mounted on poles. 12 Match the two parts of each sentence. 1) Power plants generate a convert electricity from high voltage levels to lower levels. 2) Transmission lines are used b in case of an expected demand for electric power. 3) High voltages mean c a reduction in energy losses during transmission. 4) Step-down transformers d power and distribute it to substations. 5) Substations can help each other e can be safely used in businesses and homes. 6) The current transmitted by poles f to distribute high-voltage electricity to a network of substations. 2 3 4 1 5 6 13 Write a summary about power sources and energy saving in our life. Translating 14 Translate the following sentences into Chinese. 1) Each atom is composed of a small central nucleus consisting of protons and neutrons around which orbit shells of electrons. ___________________________________________________________________________________________________ 2) The electrons in the outermost shell are called valence electrons and the electrical properties of the substance depend on the number of these electrons. ___________________________________________________________________________________________________ 3) Neutrons have no electric charge, but protons have a positive charge while electrons have a negative charge. ___________________________________________________________________________________________________ 4) Direct current is a continuous flow of electrons in one direction and it never changes its direction until the power is stopped or switched off. ___________________________________________________________________________________________________ 5) Alternating current has a great advantage over direct current because it can be transmitted over very long distances through small wires, by making energy high voltage and low current. ___________________________________________________________________________________________________ 6) Nuclear power requires little fuel and causes much less air pollution than other power plants, but it can cause severe health and environmental problems when accidents occur, with a consequent release of radioactive material. ___________________________________________________________________________________________________ 7) Sunlight can be directly converted into electricity by solar cells made of silicon. ___________________________________________________________________________________________________ 8) The wind turns the blades of giant turbines, producing in this way kinetic energy which is then converted into mechanical power and electricity by a generator. ___________________________________________________________________________________________________ Technical Terms nucleus n. the part of an atom that contains most of its mass and that carries a positive electric charge 原子核；核 proton n. a type of elementary particle (= a very small piece of matter) with a positive electrical charge that is found in the nucleus of all atoms 质子 neutron n. a part of an atom that has no electrical charge 中子 electron n. an extremely small piece of matter with a negative electrical charge 电子 uranium n. a chemical element that is a heavy, silver-white, radioactive metal used mainly in producing nuclear energy 铀（放射性化学元素） fission n. the act or process of splitting the nucleus (= central part) of an atom, when a large amount of energy is released（核）裂变，分裂 ampere (A) n. the standard unit of measurement for the strength of an electrical current 安 培（电流单位） coulomb (C) n. a unit for measuring electric charge 库仑（电量单位） watt (W) n. a unit for measuring electrical power 瓦，瓦特（电功率单位） kilowatt (kW) n. a unit for measuring electrical power 千瓦（电的功率计量单位，等于1 000瓦 特） Unit 3 Electricity and Power 47 UNIT Electric Circuits 4 Learning Objectives Upon completion of the unit, students will be able to: . describe what a simple circuit consists of; . name examples of loads; . build a simple electric circuit with several loads. Starting Off When you turn on a light in your house, do you know how electricity is transmitted? Please build a simple electric circuit and see what happens. Reading 1 An electric circuit or network is a pathway through which the electric current can flow. A simple circuit consists of a power source, two conducting wires, each one attached to a terminal of the source and a device through which electricity can flow. This device is called a load and it’s attached to the wires. If all the parts are properly connected, the current flows and the lamp lights up. This kind of circuit is called “closed”. On the contrary, if the wires are disconnected the circuit is called “open” or “broken”. The circuit can be opened and closed by a device called a switch. Loads can turn electrical energy into a more useful form. Some examples are: light bulbs, which change electrical energy into light energy; electric motors, which change electrical energy into mechanical energy; speakers, which change energy into sound. The source provides the electrical energy used by the load. It can be a storage battery or a generator. The switch interrupts the current delivered to the load by the source and allows us to control the flow. When an abnormally high amount of current passes through a network, you get a short circuit. This may occur when there is a drop in the resistance or a broken insulation. In order to prevent short circuits, it is best to use fuses, which melt when too much current flows through them, interrupting in this way the circuit. 50 机电英语 1 Read the text and label the picture with the name of each part. 1) 3) 2) 4) 5) 2 Match the words and phrases with their definitions. 1) load a a device which interrupts the circuit 2) switch b a circuit in which wires are disconnected 3) source c a device which provides power 4) fuse d a complete circuit with no breaks at all 5) closed circuit e a device which consumes electric power 6) broken circuit f a protective device Reading 2 A fuse can be added to an electric circuit to protect it from the effects of undue power. This safety device, which is made of a heat-sensitive alloy, is connected in series with the circuit it has to protect. If an excessive amount of current flows through the circuit, the alloy will liquefy and open the circuit. A circuit breaker is fundamental in a house to protect circuits against overloading, overheating and short circuits. The advantage of a circuit breaker is that it can be reset after the overloading by replacing the fuse. A professional electrician should always provide his customers with a map of the electric circuit in the house so that it will be easier to work on it in case of faults. 3 Read the text and find synonyms for the words and phrases below. 1) excessive: ________________ 2) reacting to high temperatures: ________________ 3) melt: ________________ 4) loading up: ________________ 5) adjusted: ________________ 6) clients: ________________ 4 Read the text about conventional circuit elements and complete the missing information. An electric circuit may include some various conventional circuit elements. The available circuit elements fall broadly into the classes of ____________________ elements, ____________________ elements, ____________________ devices including inductors and ____________________, semiconductor devices operated in the ____________________ mode, and semiconductor devices operated in the ____________________ mode. MY GLOSSARY circuit n. 电路 device n. 装置，器械 load n. 电负荷，电负载 light bulb 电灯泡 speaker n. 扬声器，喇叭； 发言者，演讲者 undue adj. 过分的，过度的 liquefy v. （使）成为液 体，使液化 overload v. 使超载，使负荷过重 fault n. （机器或系统的）毛病，故 障，缺陷；过错，过失；责任 Listening 5 Complete the text about series circuit and parallel circuit with the words and phrases in the box according to what you hear. components current turn on branch amount positive appliances continue burns out path The (1) components of a circuit can be wired in two different ways: series or parallel. If components are arranged one after another to form a single (2) between the terminals and the components, the circuit is known as a series circuit. In this type of circuit, the (3) flows from the negative terminal to the (4) terminal, passing through all the other components of the circuit. This means that the (5) of energy passing through all the components in the series is the same. The main disadvantage of a series circuit is that when a single component in the path (6) , the entire circuit stops operating (e.g. Christmas tree lights). A parallel circuit consists of several paths connecting the different components. Each separate path is called a (7) of the circuit. Current from the source divides and flows through the different branches. Unlike series circuits, if one of the components in the parallel circuit burns out, the other paths (8) to operate. Parallel circuits are commonly used to connect (9) at home, so that each socket can function independently. For example, you don’t have to (10) the light in your room for the TV socket to work. R1 + R2 - R3 + R1 R3 R2 - Speaking 6 Discuss the following questions and practice them with each other. 1) What does a simple circuit consist of? 2) What happens to the lamp in a closed circuit? 3) Can you name some examples of loads? 4) What is a generator? 5) What is the function of a switch? 6) When does a short circuit occur? 7) What can we use to prevent short circuits? 8) How does a fuse work? Writing 7 Write a summary of compositions of electric circuits. 8 Write a short passage to explain how to build a simple electric circuit. Translating 9 Translate the following sentences into Chinese. 1) A simple circuit consists of a power source, two conducting wires, each one attached to a terminal of the source and a device through which electricity can flow. ___________________________________________________________________________________________________ 2) When an abnormally high amount of current passes through a network, you get a short circuit. ___________________________________________________________________________________________________ 3) In order to prevent short circuits, it is best to use fuses, which melt when too much current flows through them, interrupting in this way the circuit. ___________________________________________________________________________________________________ 4) A parallel circuit consists of several paths connecting the different components. ___________________________________________________________________________________________________ 5) A fuse can be added to an electric circuit to protect it from the effects of undue power. ___________________________________________________________________________________________________ 6) A circuit breaker is fundamental in a house to protect circuits against overloading, overheating and short circuits. ___________________________________________________________________________________________________ 7) A professional electrician should always provide his customers with a map of the electric circuit in the house so that it will be easier to work on it in case of faults. ___________________________________________________________________________________________________ Technical Terms short circuit a failure in an electrical circuit , when electricity travels along the wrong route because of damaged wires or a fault in the connections between the wires 短路 fuse n. a small wire or device inside a piece of electrical equipment that breaks and stops the current if the flow of electricity is too strong 保险丝，熔断器 circuit breaker a device that trips like a switch and opens the circuit when overloaded 断路器 Unit 4 Electric Circuits 55 UNIT Electronics 5 56 机电英语 Learning Objectives Upon completion of the unit, students will be able to: . have a basic knowledge about electronic development; . fully understand the electronic circuits; . explain the function of some electronic devices in mobile phones. Starting Off What is electronics? How can we use electronic device to convey a signal? In this unit, we can learn about these. Reading 1 Electronics is the branch of science which controls electricity in order to convey a signal using semiconductor materials. These signals represent numbers, letters, sounds, pictures, computer instructions or other information. Radio systems were developed to read and understand these signals and in 1920 radio broadcasting started, making it possible for electromagnetic waves to travel long distances. More sophisticated devices were needed during the Second World War and the invention of radar (Radio Detection and Ranging) represented a further step in electronics, making it possible to determine the altitude, direction and speed of moving and fixed objects. The invention of television in the 1920s was one of the most revolutionary and popular inventions in history and it showed the importance of electronics in certain branches of industry. For the first time in history it became possible to transmit images and sound over wire circuits. The first computer appeared in 1946. This machine, which could solve a wide range of computing problems, was built over a period of three years by a team of American scientists working at the University of Pennsylvania. It was a huge machine weighing almost 50 tons. The first transistor was assembled in 1957 by a team of scientists working at the Bell Laboratories in the U.S.A., and it was a real coming of age in the science of electronics because it replaced the use of valves. Transistors are very small, easy to handle, cheap, and they use little power. The silicon chip—which followed the transistor in the 1960s— can contain up to several thousand transistors packed and interconnected in layers beneath the surface. It is really tiny (usually less than one centimetre square and about half a millimetre thick) and it has paved the way to microelectronics. Electronics has influenced and improved the way information is stored, processed and distributed. Social and personal life has been deeply affected by these inventions and many financial, business, medical, education and political routines have been speeded up. 1 Read the text about the main inventions in electronics and complete the table with the missing information. Invention Year Function read and understand electronic signals Radar 1920s Unit 5 Electronics 59 Reading 2 Electronic circuits A conventional electronic circuit is made of separate components attached to a base called a printed circuit board (PCB). Before being finalised and manufactured, the electronic circuit must be tested many times on an experimentation board called a breadboard. It consists of a perforated block of plastic with several spring clips connected by copper wires. It doesn’t require soldering as its components can be pushed straight into the holes, so it is easy to change connections and replace pieces. It is generally used to create temporary prototypes and experiment with circuit design. The integrated circuit, also known as a chip, is one of the most important inventions of the 20th century. Integrated circuits are used in almost all electronic equipment today, for example watches, calculators and microprocessors. It consists of millions of transistors and other electronic components combined to form a complex set on a thin slice of silicon or other semiconductor material. Chips are becoming tinier and tinier and they are produced in large quantities so that costs are reduced. Since signals have to travel a short distance, they work faster, consume less power and generate less heat. They are also more reliable given the limited amount of connections which could fail. The microprocessor is the heart of any normal computer: it is a logic integrated circuit chip which can carry out a sequence of operations when it receives instructions from different input devices. As it doesn’t contain a large memory, it can’t work alone but needs to be supported by other integrated circuits to be connected with peripherals. Most microprocessors are found inside computers and are called the CPU (Central Processing Unit). In order to work properly, the microprocessor needs to receive instructions from a memory chip. These instructions are then decoded, executed and elaborated so as to get the results available. The most sophisticated microprocessors can contain up to 10 million transistors and run 300 million cycles per second. It means that the computer can perform about a billion instructions every second. As technology continues to evolve, microprocessors are becoming tinier and tinier. 2 Read the text about the different kinds of electronic circuits and match the words with their definitions. 1) prototype a to convert an electrical signal into another code 2) perforated b the act of joining metallic parts 3) soldering c an original model used to test a circuit or a product 4) fail d to perform ineffectively 5) peripheral e having a series of holes 6) decode f an auxiliary device that works with a computer 3 Read the text again and answer the questions. 1) What is a conventional circuit made of? 2) What does PCB stand for? 3) What is a breadboard? 4) What does a chip consist of? 5) What is a chip made out of? 6) What are the advantages of chips compared to conventional electronic circuits? 7) What is a microprocessor? 8) How many instructions can computers perform every second? MY GLOSSARY convey v. 传达，表达；运送 signal n. 信号 broadcasting n. 广播，播音；播送 wave n. & v. 波，周波；振动；挥 舞，挥动；摆动，摇 晃 sophisticated adj. 精密的，复杂巧妙的 further adj. & adv. （far 的比较级）更 远的（地），在更大 程度上；进一步的 （地） altitude n. 海拔，高度；高地 tiny adj. 微小的，极小的 pave the way 为某事铺平道路 speed up 加速 breadboard n. 试验电路 板 perforate v. 打孔，穿孔 spring clip 弹簧夹 soldering n. 焊锡，焊料 slice n. 薄片 peripheral n. & adj. 外围设备，周边设 备；次要的，附带的； 外围的，周边的 decode v. 解码，译解 execute v. 执行，实行 elaborate v. & adj. 精心制作；精心制作 的，复杂的 evolve v. 发展，进化 Listening 4 Listen to the text about mobile phones and complete the missing information with the words in the box. cell lines microprocessor photos radio signals flash emails antenna movement A cellular phone (or mobile phone) is designed to give the user freedom of (1) while using a telephone. It uses (2) signals to communicate between the phone and the (3) . The server area is divided into smaller areas called cells and an antenna is placed within each cell and connected by telephone (4) . These lines connect cellular phones to one another: a computer selects the antenna closest to the telephone when a call is made. If the phone moves to one serving (5) to another, the radio signal is transferred to the actual cell without interrupting the conversation. The circuit board is the heart of the system. A chip translates the outgoing and incoming (6) from analogue to digital and back from digital to analogue. The (7) handles all the functions for the keyboard, the display and the loudspeakers, and it controls the signal to the base station. Other (8) memory chips provide storage for the operating system. A cellular phone is not only a phone but it provides an incredible amount of functions: store information; use a calculator; send and receive (9) ; surf the Internet; play simple games; play music, take (10) and videos. Can you imagine your life without your mobile phone? 5 Listen to the text again and decide if the following statements are true (T) or false (F). T F　　　　 1) Mobile phones use radio signals to communicate. 　　　　 2) The server area is divided into smaller areas called stations. 　　　　 3) An antenna is placed every two or three cells. 　　　　 4) Communication with a mobile within a cell is independent from the base station. 　　　　 5) There are interruptions when you move to one cell to another. 　　　　 6) The antenna is the heart of the system. 　　　　 7) The signal must be translated. 　　　　 8) The flash memory handles all the functions. 　　　　 9) Loudspeakers are controlled by the microprocessor. 　　　　 10) You can text and send emails with your mobile phone. 　　　　 Speaking 6 Discuss with your partner about the difference between conventional electric circuit and integrated circuit, as well as microprocessors of each other. Writing 7 Write a summary about electronic circuits including PCB, the integrated circuit and the microprocessor. 8 Think of an electronic device (TV, radio, mobile phone, computer, etc.) you use every day. Write down its function, advantages, disadvantages and your opinion on them. Translating 9 Translate the following sentences into Chinese. 1) Electronics is the branch of science which controls electricity in order to convey a signal using semiconductor materials. ___________________________________________________________________________________________________ ___________________________________________________________________________________________________ 2) The first transistor was assembled in 1957 by a team of scientists working at the Bell Laboratories in the U.S.A., and it was a real coming of age in the science of electronics because it replaced the use of valves. ___________________________________________________________________________________________________ ___________________________________________________________________________________________________ 3) The silicon chip—which followed the transistor in the 1960s—can contain up to several thousand transistors packed and interconnected in layers beneath the surface. ___________________________________________________________________________________________________ ___________________________________________________________________________________________________ 4) Social and personal life has been deeply affected by these inventions and many financial, business, medical, education and political routines have been speeded up. ___________________________________________________________________________________________________ ___________________________________________________________________________________________________ 5) A conventional electronic circuit is made of separate components attached to a base called a printed circuit board (PCB). ___________________________________________________________________________________________________ ___________________________________________________________________________________________________ 6) The integrated circuit, also known as a chip, is one of the most important inventions of the 20th century. ___________________________________________________________________________________________________ ___________________________________________________________________________________________________ 7) The most sophisticated microprocessors can contain up to 10 million transistors and run 300 million cycles per second. ___________________________________________________________________________________________________ ___________________________________________________________________________________________________ Technical Terms electromagnetic adj. having magnetic and electrical parts 电磁的 transistor n. a small electrical device containing a semiconductor, used in televisions, radios, etc. to control or increase an electric current 晶体管 valve n. a device that opens and closes to control the flow of liquids or gases, or a similar structure in the heart and the veins that controls the flow of blood 阀；活门；瓣膜 chip n. (also microchip) a very small piece of semiconductor, especially in a computer, that contains extremely small electronic circuits and devices, and can perform particular operations （尤指计算机的）集成电路片， 芯片 microelectronics n. the science and technology involved in the making and using of very small electronic parts 微电子学 microprocessor n. a part of a computer that controls its main operations 微处理器 Unit 5 Electronics 65 Telecommunications and Networks UNIT 6 Learning Objectives Upon completion of the unit, students will be able to: . understand the telecommunication systems and network topologies; . draw a simple diagram about network; . compare advantages and disadvantages of using a network. Starting Off We are used to making phone calls, watching TV, chatting online and emailing. Do you know which belong to means of communication and which use network? Reading 1 Communication has always played a crucial role in human societies and over time its forms have evolved through the progression of technology, transforming itself into telecommunication. The telegraph, the telephone, the radio, the television, the radar, the fax and, more recently, the computer are all devices which were invented to communicate using electromagnetic waves. Thanks to them, we can transmit texts, pictures, sounds and images and reach everyone in any part of the world. Ground transmission Wires provide a cheap and effective means of communication that was predominant in the past. Wires, which are made out of copper and insulated with plastic, can be single or twisted, and they are used mainly in telephone and computer networks. Coaxial cables consist of an inner conductor insulated with plastic and surrounded by a woven copper shield. They are used in television and radio as these cables can support about 60 channels. The inner copper cable is insulated to protect the wires from bending and crushing and to reduce the noises. Optical fibres are used in place of simple copper wires to carry larger amounts of information. They consist of strands of pure glass as thin as a human hair. Signals travel along fibres with less loss and without any electromagnetic interference. As they permit transmission over longer distances and at a higher speed, they are used in communication systems, in some medical instruments and in a wide variety of sensing devices. Air transmission Antennas were invented to capture radio signals and convert them into electrical signals through the receiver. They can also receive electrical signals from the transmitter and convert them into radio signals. These electric devices, which provide information at a cheap rate, are essential to all equipment that uses radio. They are used in systems such as radio and television broadcasting, radar, mobile phones, and satellite communications, for which they are in form of dishes. Satellites are machines launched into space to move around Earth or another celestial body. A communications satellite is basically a station which receives signals in a given frequency and then retransmits them at a different frequency to avoid interference problems. The first satellite was launched by the Soviet Union in 1957. There are different types of satellites: low-orbit satellites, which travel at about 300 km from the Earth and observe the planet, providing accurate information about agriculture, pollution and weather forecasting; medium-altitude satellites, which travel at about 9,000–18,000 km from the Earth and are used in telecommunications. 1 Read the text about the different kinds of transmission media and complete the table. Means of transmission Material Function Type of signal (ground or air) Advantages wires coaxial cables optical fibres antennas satellites Unit 6 Telecommunications and Networks 69 Reading 2 A network is a group of computers linked together. It consists of at least two computers joined by cables on the same desk or same office, but it can also mean thousands of computers across the world. The users of a network can share hardware (scanner, printer, fax machine, etc.), access data in other people’s computers and run other programs stored in the network although not installed on their own computer. A network consists of: nodes, that is to say different computers and devices; a connecting medium, such as cables or a wireless connection; routers, which are special computers enabled to send messages; switches, that is to say devices which help to select a specific path to follow. Networks can be connected in different ways according to the area they cover. A LAN (Local Area Network) is generally located in a limited space, such as a building or a campus. On the contrary, a WAN (Wide Area Network) operates in a larger area and it can reach most of the world, so it could be described as a collection of LANs all over the world. The exchange of information in a network is controlled by communications protocols, which define the formats and rules that computers must follow when talking to one another. Well-known communications protocols are Ethernet, which is a family of protocols used in LANs, and the Internet Protocol Suite, which is used in any computer network. Computer networks offer many advantages. For example, they facilitate communication, allowing people to send emails and texts, make phone/video calls and videoconference. Furthermore, networks allow people to share files, data, and other types of information as users may access data and information stored on other computers in the network. On the other hand, networks may be difficult to set up and may be insecure as computer hackers can send viruses or computer worms to the net computer. They may also interfere with other technologies, as power line communication strongly disturbs certain forms of radio communication and access technology such as ADSL. 2 Read the text about networks and answer the questions. 1) What does a network consist of? 2) What is a router? 3) What is a LAN? 4) What is a WAN? 5) What is the function of communications protocols? 6) What is Ethernet used for? 7) What are the advantages of using a network? 8) What are the disadvantages of using a network? 3 Read the texts about the different network topologies and fill in the gaps with the words in the box. nodes circle network pathway affect configure small destination star failure exchanging backbone A network topology is the layout of the interconnections of the nodes of a computer network. It depends on the distance involved, the type of hardware used and the stability needed. Bus network In a bus network all (1) nodes are connected to a common medium, called backbone, as it happens with Christmas lights. Information sent along the (2) travels until the destination is reached. This kind of topology is generally used only for (3) networks, as it isn’t able to connect a large number of computers. The main advantage offered by this topology is that if a computer or device doesn’t work, it doesn’t (4) the others. Star network In a star network all nodes are connected to a special central node called the hub. Once it has received a signal, the hub passes it to all the other nodes until it reaches the (5) computer. This means that all the computers and devices are joined together. This topology is commonly used in businesses because it can grant rapidity and safety in (6) data. Thanks to this topology, data is always up-to-date and if a computer doesn’t work, it doesn’t affect the others. The only disadvantage to it is that if the hub goes down, the whole (7) doesn’t work. Ring network In a ring network each node is connected to its left in a(n) (8) . There is no central hub that holds all the data, and communication is sent in one direction around the ring through the use of a token. As it requires fewer cables, this topology is less expensive. Nonetheless, because it provides only one (9) among the nodes, a single node (10) may isolate all the devices attached to the ring. Star bus topology Star bus topology is the most common network topology used today. It combines elements of star and bus topologies to create a more effective network. Computers in a specific area are connected to hubs creating a(n) (11) , and then each hub is connected together along the network backbone. The main advantage of this type of topology is that it can be more easily expanded over time than a bus or a star. On the other hand, this topology is more difficult to (12) than the others and if the backbone line breaks, the whole network goes down. 4 Read the above text again and complete the table with the missing information. Topology Connection Use Advantages Disadvantages small networks Each node is connected to the central hub. ring MY GLOSSARY predominant adj. 主导的，盛行的；显著的 twisted adj. 扭曲的，变形的 coaxial adj. 同轴的，共轴的 inner adj. 里面的 surround v. 环绕，围绕，包围 woven v. （weave 的过去分词） 编织 shield n. 保护物，屏障；盾（牌）； 保护者 strand n. （线、绳等 的）缕，股； 部分，方面 sensing device 读出装置；传感器，灵敏 元件 receiver n. 接收者，接收方 dish n. 盘子，碟子 celestial adj. 天空的，天上的 forecasting n. 预测，预报 node n. 节点 Listening 5 Listen to the text about different networks and match the networks with their diagrams. 1) bus network 2) ring network 3) star bus topology 4) star network 6 Listen to the text again and decide if the following statements are true (T) or false (F). T F　　　　 1) The topology chosen depends only on the location of computers. 　　　　 2) All topologies use many cables and are very expensive. 　　　　 3) In a bus topology all the buses are connected one after the other. 　　　　 4) In a bus topology a server controls the flow of data. 　　　　 5) In a star network data is always updated. 　　　　 6) The hub doesn’t connect printers and other devices in a star topology. 　　　　 7) In the ring topology each node is connected to the hub. 　　　　 8) In the ring topology if the hub doesn’t work, the network goes down. 　　　　 9) Star bus topology combines elements of bus and ring topologies. 　　　　 10) In a star bus topology a backbone line failure affects the whole network. 　　　　 Speaking 7 Look at the following means of communication and take turns asking and answering the following questions. How often do you use them? What do you use them for? Who do you use them with? What are their advantages? Can you think of any risks connected with their use? Writing 8 Look at the diagram and complete the text about telecommunication systems. 9 Refer back to the text and write a summary of the components, pros and cons of networks and describe a situation in which a network can be very useful. MEANS OF TRANSMISSION radio waves cables wires antennas coaxial cables satellites optical fibres Telecommunication systems need means for the (1) of any information, which is translated into electromagnetic waves that connect the transmitter to the receiver. These means can be physical media, such as (2) , or radio (3) , which are transmitted by air. Different kind of cables can be used. The simplest communication cables consist of a single pair of (4) twisted together. Other types are (5) cables and optical (6) . Radio waves need (7) to be transmitted and sometimes (8) are necessary for long-distance transmission. Unit 6 Telecommunications and Networks 75 Translating 10 Translate the following sentences into Chinese. 1) Coaxial cables consist of an inner conductor insulated with plastic and surrounded by a woven copper shield. ___________________________________________________________________________________________________ ___________________________________________________________________________________________________ 2) Optical fibres are used in place of simple copper wires to carry larger amounts of information. ___________________________________________________________________________________________________ ___________________________________________________________________________________________________ 3) Antennas were invented to capture radio signals and convert them into electrical signals through the receiver. ___________________________________________________________________________________________________ ___________________________________________________________________________________________________ 4) A network is a group of computers linked together. ___________________________________________________________________________________________________ ___________________________________________________________________________________________________ 5) Networks can be connected in different ways according to the area they cover. ___________________________________________________________________________________________________ ___________________________________________________________________________________________________ 6) Well-known communications protocols are Ethernet, which is a family of protocols used in LANs, and the Internet Protocol Suite, which is used in any computer network. ___________________________________________________________________________________________________ ___________________________________________________________________________________________________ 7) On the other hand, networks may be difficult to set up and may be insecure as computer hackers can send viruses or computer worms to the net computer. ___________________________________________________________________________________________________ ___________________________________________________________________________________________________ Technical Terms antenna n. an electrical device that sends or receives radio or television signals 天线 transmitter n. a piece of equipment for broadcasting radio or television signals（广播、电视信 号的）发射台，发射机 LAN n. abbreviation for “local area network”: a system for connecting the computers of people who work in the same building 局部区域网，局域网（local area network 的缩写） protocol n. a computer language allowing computers that are connected to each other to communicate 规程，协议（计算机之间交换信息的计算机语言） Ethernet n. a system for connecting computers into networks (=groups of computers that are used together) 以太网 ADSL n. abbreviation for “asymmetric digital subscriber line”: a system for providing a very fast internet connection that allows you to use a phone at the same time 非对称数字用户线路 topology n. the branch of mathematics concerned with generalisation of the concepts of continuity, limit, etc 拓扑学；拓扑结构 Unit 6 Telecommunications and Networks 77 Computer: History and Technology UNIT 7 Learning Objectives Upon completion of the unit, students will be able to: . describe the history of computer; . analyse the structure of computer; . compare the difference among different computers. Starting Off Look at the title of the unit, what do you think the topic is about? Reading 1 The computer evolution The word “computer” was first used in 1613 to describe a person who performed calculations, but now the term almost universally refers to automated electronic machinery. Its history started more than 2,000 years ago in Babylonia (Mesopotamia), when the abacus, a wooden rack holding two horizontal wires with beads strung on them, came into use. First computers were used primarily for numerical calculations. In the 16th century Leonardo da Vinci drew sketches for a machine that were sufficiently complete and correct for modern engineers to build a calculator on their basis. A century later, in 1623, the first calculator was built by German astronomer and mathematician Wilhelm Schickard, but we have to wait for French mathematician-philosopher Blaise Pascal to see the production of a machine in 1644. It was called Pascaline, or Arithmetic Machine, and it was invented for Pascal’s father to help him with his tax collection job. It could only perform additions and subtractions. In 1822, Charles Babbage began developing the Difference Engine, considered the first mechanical computer or automatic computing engine. Later, in 1837, he proposed the first general mechanical computer, the Analytical Engine. The machine was designed to consist of four components: the engine, the store, the reader, and the printer. These elements are the essential components of every computer today. In 1946, nearly a century later, the ENIAC (Electronic Numerical Integrator Analyzer and Computer) was built by the United States. It was the first electronic digital computer which was fully functional. It occupied about 1,800 square feet, the size of a large room, and weighed almost 50 tons. This first generation of computers used vacuum tubes, about 18,000 were used for the ENIAC. They could only perform single tasks, and they had no operating system. The second generation of machines started in the 1950s. They used transistors which were more reliable than vacuum tubes. In 1950, the UNIVAC 1101 was the first computer capable of storing and running a program from memory. During this generation of computers over 100 computer programming languages were developed. In 1953 IBM publicly introduced the 701, its first electric and mass-produced computer. The invention of the integrated circuit brought us the third generation of computers. Computers became smaller, more powerful and more reliable, able to run many different programs at the same time. In1980 Microsoft Disk Operating System (MS-Dos) was launched and in 1981 IBM introduced the personal computer (PC) for home and office use. Three years later Apple created the Macintosh computer with its icon driven interface and the 90s gave us Windows operating system. In 2010 the first iPad, a tablet computer, was unveiled. As a result of the various improvements to the development of the computer we have seen the computer being used in all areas of life. It is a very useful tool that will continue to experience new development as time passes. 1 Read the text and complete the table with the missing information. When What Who 400 BC 16th Century 1613 1623 1644 1837 1946 1953 1981 2010 ________________________________________ ________________________________________ ________________________________________ ________________________________________ ________________________________________ ________________________________________ ________________________________________ ________________________________________ ________________________________________ ________________________________________ ________________________________________ ________________________________________ ________________________________________ ________________________________________ ________________________________________ ________________________________________ ________________________________________ ________________________________________ ________________________________________ ________________________________________ 2 Read the text about Steve Jobs and complete it with the words from the box. Apple iPad technological battle evolution products Macintosh computers Steve Jobs was born in 1955 in San Francisco, California. At school he showed great (1) _________________ interests. Jobs experimented with different scientific attempts before starting Apple (2)_________________ with Steve Wozniak in 1976. Together they created the (3)_________________ I and Apple II computers. In 1984, the (4)_________________ computer was launched. Apple’s revolutionary (5)_________________, which include the iPod, iPhone and (6)_________________, are now seen as dictating the (7)_________________of modern technology. He died in 2011, after a long (8) _________________ with cancer. 3 Read the text about computer components and complete the table. A computer is an electronic device that performs high-speed mathematical or logical operations and executes instructions in a program. Its main functions are to accept and process data to produce results, store information and programs and show results. The main characteristics of these powerful machines are: speed, as they can execute billions of operations per second; high reliability in the elaboration and delivery of data; storage of huge amounts of information. A computer consists of hardware and software. The word “hardware” refers to all the components you can physically see such as the CPU (Central Processing Unit), the internal memory system, the mass storage system, the peripherals (input and output devices) and the connecting system. Software, instead, comprises all the computer programs and related data that provide the instructions for a computer to work properly. The CPU is the brains of your computer and consists of ALU (Arithmetic Logic Unit), which carries out the instructions of a program to perform arithmetical and logical operations, and CU (Control Unit), which controls the system and coordinates all the operations. In order to memorise input and output data, there is an internal memory that can be distinguished into volatile and non- volatile. Volatile memory is memory that loses its contents when the computer or hardware device is off. Computer RAM (Random Access Memory) is a good example of volatile memory. It is the main memory of the computer where all data can be stored as long as the machine is on. On the contrary, a non-volatile memory contains information, data and programs that cannot be modified, or can be modified only very slowly and with difficulty. Computer ROM (Read Only Memory), for example, contains essential and permanent information and software which allow the computer to work properly. Memory storage devices are available in different options, sizes and capacities. These devices are extremely useful; they can be rewritten and offer incredible storage capacity, up to 8 TB. They can be magnetic (hard disks), optical (CDs and DVDs) or solid (flash memory cards). Mass storage devices are available in an incredible number of options with different storage capacity up to 8 TB for some portable drives. A very popular type of removable device is represented by USB flash drives, which are much smaller and lighter than other portable drives, but which can still provide a huge storage capacity. Component (acronym) Full name / Description Functions and properties hardware software CPU ALU CU RAM ROM 4 Read the text and complete the definitions with the words and phrases in the box. mouse speaker modem keyboard printer disk drives monitor scanner We call hardware the equipment involved in the functioning of a computer. It consists of several components that can either send data to the computer (input devices) or convert and transfer data out of the computer in the form of text, sound, image, or other media (output devices). The main input and output devices are: 1) : this is the display, which helps you control computer operations. It accepts video signals from a computer and shows information on a screen. The first models used cathode ray tubes (CRTs), which was the dominant technology until they were replaced by liquid crystal displays (LCDs) in the 21st Century. 2) : this is like a typewriter with an arrangement of keys corresponding to written symbols. It is generally used to type text and numbers in a word processor. However there are some special keys or combination of keys which, pressed simultaneously, can produce actions or computer commands. 3) : this is a dynamic pointing device used to move the cursor on the screen. It consists of a plastic case, a little ball that sends impulses to the computer when rolled on a flat surface, one or more buttons, and a cable that connects the device to the computer. Modern computers are provided with built-in pointing devices that let you control the cursor by simply moving your finger over a pad. 4) : this captures images from printed pages or photos and converts them into digital data. They usually come with software that lets you resize or modify a captured image. 5) : this receives text and graphics from a computer and transfers the information to paper. It may vary in size, speed, sophistication, and cost. In general, more expensive models are used for higher-resolution colour printing. 6) : this converts electrical signals into sounds and allows you to listen to music, multimedia web sites and conversations with other people. 7) : this is a device or program that enables a computer to transmit data over telephone lines, by converting digital signals into analog waves. It can be either internal or external to your computer. 8) : these are devices that allow you to read and write data on disks. They can be either mounted inside the computer and store the computer operating system and all the documents and programs, or come in the form of removable devices. 5 Read the descriptions of the different types of computers and match them with the correct picture. When you go to a computer shop, you can find computers for any use, size or capability. 1) Desktop: this is a personal computer intended for regular use at a single location. It’s designed to sit on your desk, and as such it consists of a monitor and a tower with extra drives inside. 2) Laptop: this is a portable computer, which integrates all the usual components of a desktop computer into a single unit. Smaller versions of laptops are known as notebooks. It is useful for people who do not have a fixed place to work at. They are lighter and handier than desktop computers, but they also tend to be more expensive. They require an expensive battery that needs to be recharged quite often. 3) Netbook: this is a portable computer, with limited capabilities as compared to standard laptops. It is smaller and lighter, but it also has less processing power than a full- sized laptop. It is useful for people who don’t have a fixed place to work at or for those who travel, but still need to surf the Net. They use a battery which needs to be recharged often. 4) Tablet: this is a small portable computer designed to have large amounts of information close to hand. They are provided with light long-lasting batteries and special operating systems. They don’t require any keyboard but use touch screens to enter data and access information. 5) Mainframe: this is a very large and expensive computer capable of supporting thousands of users at the same time. For this reason, it is used in businesses and it’s the centre of computer networks. These super computers, which are usually as big as a large refrigerator, are the most powerful and expensive ones and they’re used for jobs which require enormous amounts of calculations, such as weather forecasting, engineering design and economic data processing. A B C D E Reading 2 The Internet The Internet is a worldwide information system consisting of countless networks and computers, which allow millions of people to share information and data. Thanks to the Internet it is now possible for people all over the world to communicate with one another in a fast and cheap way. The Internet was first invented in the 1960s in the USA by the Department of Defence as an internal project to link computers. The Department wanted an extremely safe way of sending messages in case of nuclear attack. It was a British physicist, Sir Timothy Berners-Lee, who used it to make information available to everyone and created the most important media of the 21st century. In 1980 while working at CERN in Geneva— the largest particle physics laboratory in the world—he first thought of using hypertext to share and update information among researchers. Then from 1989 to 1990 he produced a plan to link hypertext to the Internet to create the World Wide Web. He designed and built the first site browser and editor, as well as the first web server called httpd (Hypertext Trasfer Protocol Deamon). Hypertext are the words or chains of words in a text we can click on to be linked to new sites whose content is related to the words. But how does this global system work? It is a network of people and information linked together by telephone lines which are connected to computers. The applications are based on a client/server relationship, in which your computer is the client and a remote computer is the server. All you need to join this system is a computer, a normal telephone line, a modem and an account with an Internet Service Provider (ISP), a company that provides access to the Internet. A user buys a subscription to a service provider, which gives him/her an identifying username, a password and an email address. With a computer and a modem, the user can connect to the service provider’s computer which gives access to many services, such as WWW (world wide web), emails and FTP (file transfer protocol). 6 Read the text and complete the sentences with the missing information. 1) The Internet allows people to __________________________________________________________________ 2) In the 1960s, the Internet was used __________________________________________________________ 3) Thanks to Sir Timothy Berners-Lee, ___________________________________________________________ 4) Timothy created the World Wide Web by linking _______________________________________________ 5) All you need to access the Internet is __________________________________________________________ 6) The ISP is _____________________________________________________________________________________ 7 Read the text about the different types of Internet connections and match the words in the box with the correct definition. DSL wireless satellite cable dial-up 1) ________________________________ It used to be the most common way to access the Internet. This type of connection requires you to use a landline telephone connection and a modem connected to your computer. In order to establish the connection, you must dial a telephone number provided by the ISP. Nowadays it represents the cheapest but slowest way to connect to the Internet. Another disadvantage of this type of connection is that you cannot make or receive phone calls while connected to the Internet. 2) ________________________________ A digital subscriber line is another way to connect to the Internet through a telephone connection, but the quality and speed of the connection is significantly greater than a dial-up connection. Moreover, unlike a dial-up connection, this connection is always on, which means you can still make and receive telephone calls with your landline telephone. 3) ________________________________ In order to have this type of connection you must subscribe to an account with a local cable television provider and connect a cable modem to your computer. This connection is very fast and doesn’t interfere with your telephone line. 4) ________________________________ This is one of the newest Internet connection types. This connection does not require your computer to be connected to telephone or cable wires, as it uses radio frequency bands. You simply need a modem and an account with an Internet provider. Nowadays, many coffee shops, restaurants, public libraries and schools offer this type of connection for free. However, it is typically more expensive and mainly available in metropolitan areas. 5) ________________________________ This type of connection allows a user to access the Internet via a satellite that orbits the earth. Because of the enormous distances signals must travel, this connection is slightly slower than terrestrial connections through cables. It represents an excellent option for people living in rural areas where other types of connections are not available. MY GLOSSARY evolution n. 进化，演变 calculation n. 计算；估计 machinery n. 机械装置，机器 abacus n. 算盘 astronomer n. 天文学家 addition n. 加法 subtraction n. 减法 vacuum tube 电子管，真空管 unveil v. 揭开，揭幕 countless adj. 无数的，数不清的 laboratory n. 实验室，研究室 browser n. 浏览器 subscription n. 订阅，订购 Listening 8 Listen to the text about USB flash drives and fill in the gaps with the words and phrases in the box. Then listen and check. plugged backup board moving disadvantage operating system case off-site water pocket A USB flash drive is a flash memory data storage device integrated with a USB (Universal Serial Bus) interface. USB flash drives are removable and rewritable, and they’re small enough to be carried in a (1) . These portable drives are faster, have thousands of times more capacity, and are more durable and reliable than CD-ROMs because of their lack of (2) parts. Unlike most removable drives, USB drives do not require rebooting after it’s attached. They are very robust and use very little power. They just need to be (3) into a USB port to work and they’re compatible with any modern (4) , such as Linux, Mac OS X and Windows. A flash drive consists of a small printed circuit (5) carrying the circuit elements and a USB connector, insulated electrically and protected inside a plastic (6) . The drive is often used as a (7) medium to save data, because it is very user-friendly and it can be carried (8) for safety despite being large enough for several backups. Moreover, flash drives are cheaper and less fragile than many other backup systems. Its only (9) is that it can be easily lost because of its size and it’s easy for people without a right to data to take illicit backups. Some specially manufactured flash drives are provided with a metal or rubber case designed to be waterproof and almost unbreakable. It’s been tested that these flash drives can retain their memory even after being submerged in (10) , put in a washing machine and run over with a car. 9 Listen to the text above again and decide if the following statements are true (T) or false (F), and then correct the false ones. T F　　　　 1) Flash drives are provided with a very limited storage capacity. 　　　　 2) They are lighter that other removable drives. 　　　　 3) They need an external power supply to work. 　　　　 4) USB flash drives are compatible with few operating systems. 　　　　 5) A plastic case prevents the printed circuit board from being damaged. 　　　　 6) USB drives are convenient for transferring data between computers or for personal backups. 　　　　 7) They are more expensive than other backup systems. 　　　　 8) Some models continue to work even after being accidentally dropped into water. 　　　　 Speaking 10 How much do you know about computers? Work in pairs and answer the questions. 1) What is a computer? 2) What does a computer do? 3) What are the main components of a computer? 4) Have you got a computer at home? What type is it? 5) What do you generally use your computer for? Writing 11 Write a summary of the text about the Internet in Reading 2 following the flow chart. 12 Draw a flow chart to introduce the computer development (including computer history and different technologies). Write about the importance of the Internet in your own life and describe how you use it. Write about the role of the Internet in the modern world. Explain the revolution that occurred in the 1990s. Describe the origins of the Internet and its first uses. Say how the Internet system works. Translating 13 Translate the following sentences into Chinese. 1) The word “computer” was first used in 1613 to describe a person who performed calculations, but now the term almost universally refers to automated electronic machinery. ___________________________________________________________________________________________________ 2) The ENIAC (Electronic Numerical Integrator Analyzer and Computer) occupied about 1,800 square feet, the size of a large room, and weighed almost 50 tons. ___________________________________________________________________________________________________ 3) A computer is an electronic device that performs high-speed mathematical or logical operations and executes instructions in a program. ___________________________________________________________________________________________________ 4) The word “hardware” refers to all the components you can physically see such as the CPU (Central Processing Unit), the internal memory system, the mass storage system, the peripherals (input and output devices) and the connecting system. ___________________________________________________________________________________________________ 5) Software, instead, comprises all the computer programs and related data that provide the instructions for a computer to work properly. ___________________________________________________________________________________________________ 6) On the contrary, a non-volatile memory contains information, data and programs that cannot be modified, or can be modified only very slowly and with difficulty. ___________________________________________________________________________________________________ 7) The Internet is a worldwide information system consisting of countless networks and computers, which allow millions of people to share information and data. ___________________________________________________________________________________________________ Technical Terms tablet n. a small, flat computer that is controlled by touching the screen or by using a special pen 平板电脑 volatile memory (volatile storage) a computer memory that requires power to maintain the stored information 易失存储器；非永久性存储器 laptop n. a computer that is small enough to be carried around easily and is flat when closed 手提电脑，便携式电脑，笔记本电脑 netbook n. a small laptop computer designed mainly for using the Internet 上网用小型 笔记本电脑 mainframe n. a very large, powerful computer with a lot of memory that many people can use at the same time （大型计算机的）主机，大型机 hypertext n. a way of joining a word or image to another page, document, etc. on the Internet or in another computer program so that you can move from one to the other easily 超文本 FTP (File Transfer Protocol) protocol that allows users to copy files between their local system and any system they can reach on the network 文件传输 协议（计算机通过互联网传输文件的一系列规则） Unit 7 Computer: History and Technology 91 Automation and Robotics UNIT 8 Learning Objectives Upon completion of the unit, students will be able to: . describe automation process and robotics; . compare different automation technologies; . analyse the action of sensors in industrial automated process. Starting Off Do you know new energy vehicle? How long do you think it takes to make a new energy car? Please search for some information and check it. You will find it is made so fast because of automation and robotics. Reading 1 Mechanisation refers to the process of providing human beings with machinery capable of assisting them with the muscular requirements of work. A further development of mechanisation is represented by automation, which implies the use of control systems and information technologies to reduce the need for both physical and mental work to produce goods. Automation has had a great impact on industries over the last century, changing the world economy from industrial jobs to service jobs. In manufacturing, where the process began, automation has meant that the desired results can be obtained through a series of instructions made automatically by the system, which define the actions to be done. Automated manufacturing grants higher consistency and quality, while reducing lead times and handling. It also improves work flow and increases the morale of workers when a good implementation of the automation is made. However, the purpose of automation cannot be seen only in terms of a reduction of cost and time; there are several more aspects to be taken into consideration. For example, while it is true that automation offers a higher precision in the manufacturing process, it is also true that it requires skilled workers who can make repairs and manage the machinery. The following table sums up the main advantages and disadvantages of automation: Advantages Disadvantages Speeding up the developmental process of society Disastrous effects on the environment (pollution, traffic, energy consumption) Replacing human operators in tasks that involve hard physical or monotonous work Sharp increase in unemployment rate due to machines replacing human beings Saving time and money as human operators can be employed in higher-level work Technical limitations as current technology is unable to automate all the desired tasks Replacing human operators in tasks done in dangerous environments (fire, space, volcanoes, nuclear facilities, underwater) Security threats as an automated system may have a limited level of intelligence and can make errors Higher reliability and precision in performing tasks Unpredictable costs due to research and development, which may exceed the cost saved by the automation itself Economy improvement and higher productivity High initial costs as the automation of a new product requires a large initial investment 1 Read the text about automation and match the words and phrases with their definitions. 1) manufacturing a the time between the design of a product and its production 2) information technology b the amount of confidence that a group of people have 3) goods c a set of tasks performed to complete a procedure 4) service jobs d the process of packing and distributing goods 5) skilled e the industry in which machinery is used to produce goods 6) morale f the development and application of computer systems 7) unemployment g having the knowledge and the ability to do something well 8) lead time h things that are made to be sold 9) handling i jobs in transports, communications, hospitals, energy industry, etc. 10) work flow j the state of not having a job Reading 2 Numerical control over automated devices has resulted in a rapidly expanding range of applications and human activities. Computer-aided technologies (CAx) is a broad term that means the use of computer systems to aid in the design, analysis, and manufacture of products, by serving the basis for mathematical and organisational tools used to create complex systems. It includes computer-aided design (CAD software) and computer-aided manufacturing (CAM software). The current limit of computer-aided technologies is that some abilities are well beyond the capabilities of modern mechanical and computer systems. Moreover, these technologies require high-skilled engineers and the synthesis of complex sensory data to work properly. As for costs involved, in some cases, automation is more expensive than mechanical approach. Thanks to the incredible improvements in automation technology, a number of other technologies have developed from it, such as domotics and robotics. Domotics is a field in building automation aimed at the application of automation technologies in households for the comfort and security of its residents. This means that lights, heating and conditioning systems, windows shutters, kitchen equipment and surveillance systems can be controlled by a remote control or even by a cell phone at a distance. Robotics is a special branch of automation in which the automated machines have certain human features and are used to replace human workers in factory operations. Robots are computer-controlled mechanical devices that are programmed to move, manipulate objects and interact with the environment. Nowadays more and more sophisticated robots are being built to serve various practical purposes, for example in houses, businesses, in the army and for medical appliances for disabled people. 2 Read the text about automation technologies and answer the questions. 1) What does “computer-aided technologies” mean? 2) Which software does CAx include? 3) What are the current limits of CAx? 4) Can you name two applications of automation technologies? 5) How does a domotic house differ from a traditional house? 6) What are robots used for? Reading 3 Sensors 1) ______________________________________________ Almost every industrial automated process requires the use of sensors and transducers, which are very advanced devices capable of measuring and sensing the environment and translating physical information (e.g. variations of light, pressure, temperature and position) into electrical signals. The sensor picks up the information to be measured and the transducer converts it into electrical signals that can be directly processed by the control unit of a system. 2) ______________________________________________ Because of the industrial and scientific importance of measuring, sensors are widely used in a variety of fields, such as medicine, engineering, robotics, biology and manufacturing. Traditional machines have difficulty measuring small differences in product size, so sensors can be particularly useful as they can discriminate down to 0.00013 millimetres. They can also detect temperature, humidity and pressure, acquire data and alter the manufacturing process. Sensors are also vital components of advanced machines, such as robots. 3) ______________________________________________ There are two types of sensors: analogue and digital. Analogue sensors operate with data represented by measured voltages or quantities, while digital ones have numeric or digital outputs which can be directly transmitted to computers. The sensors usually employed in manufacturing are classified as mechanical, electrical, magnetic and thermal, but they can also be acoustic, chemical, optical and radiation sensors. Moreover, according to their method of sensing, they can be tactile or visual. Tactile sensors are sensitive to touch, force or pressure and they are used to measure and register the interaction between a contact surface and the environment. These sensors are used in innumerable everyday objects, such as lift buttons and lamps which turn on and off by touching the base. Visual sensors, instead, sense the presence, shape and movement of an object optically. They are becoming more and more important in surveillance systems, environment and disaster monitoring and military applications. 3 Read the text about sensors and match each paragraph with a heading. A Sensor applications B Types of sensors C What is a sensor? 4 Read the text again and choose the correct answer. 1) Sensors pick up to be measured. A electrical signals B physical information C the control unit 2) Physical data is translated into electrical signals by . A the transducer B the sensor C a computer 3) Sensors used to alter the manufacturing process. A can’t be B are never C can be 4 sensors can transmit data directly to computers. A Chemical B Digital C Analogue 5) Tactile sensors are commonly used in . A everyday objects B military applications C sophisticated machinery 6) sensors are used to localise objects in space. A Analogue B Visual C Tactile MY GLOSSARY muscular adj. 肌肉的 goods n. 商品，货物 lead time 提前期（从最初设计到 投产的时间）；交付周 期 handling n. 处理（方式），应对（方 式）; 操作，操纵 work flow 工作流；作业流程 morale n. 士气，斗志 implementation n. 实现，履行 monotonous adj. 单调的，无变化的 disastrous adj. 极糟糕的，灾难性的 unemployment rate 失业率 broad adj. 宽广的 beyond prep. 远于，超出 synthesis n. 综合；合成 surveillance n. 监视，盯梢 army n. 军队；团体，队伍 disabled adj. 残疾的，丧失能力 discriminate v. 辨别；区别；歧视 humidity n. 湿度 analogue adj. 模拟的 acoustic adj. 声学的，听觉的 tactile adj. 触觉的 lift n. & v. 电梯；举起，提起，抬 起，吊起 Listening 5 Think of what robots can do nowadays and tick (√) the boxes below. Then listen and check your answers. Nowadays robots can... get sick see obstacles go underwater speak fluently handle dangerous material smell things clean nuclear waste taste food explore volcanoes move objects go to space have feelings easily walk on two legs 6 Read the text about the computer mouse and underline the correct option. Then listen and check. The mechanical mouse has a ball which rotates and translates the (1) motion/temperature of our hand into signals that the computer can use. Developed in late 1999, the optical mouse is an advanced computer pointing device that uses a light-emitting diode (LED), an (2) acoustic/optical sensor and a digital signal processor (DSP) in place of the traditional mouse ball and electromechanical transducer. The optical mouse actually uses a tiny (3) camera/recorder to take thousands of pictures at a rate of more than 1,000 images per (4) minute/second. Optical mice can work on many surfaces without a mouse pad, thanks to an LED that bounces light off the surface it is on onto an optical sensor. The sensor sends each image to a digital signal (5) processor/transistor which examines how the patterns have moved since the previous image, determining how far the mouse has moved. The computer then moves the cursor on the screen based on the coordinates received from the mouse. This happens hundreds of times each second, making the cursor appear to move very (6) slowly/smoothly. The best surfaces reflect but some others, for example a blank sheet of white (7) plastic/paper, do not allow the sensor and DSP to work properly because the details are too small to be detected. In addition to LEDs, a recent innovation are laser-based optical mice that detect more surface details compared to LED technology. This results in the ability to use a mouse on almost any surface and to (8) reduce/increase the resolution of the image. Speaking 7 What would you like to automate in your life? In pairs, discuss the impact of automation on your own life and list its main advantages and disadvantages. Writing 8 Please write a summary about automation and robotics according to the texts. 9 What do you think about the future of robotics? Please write a short passage to describe it. Translating 10 Translate the following sentences into Chinese. 1) Mechanisation refers to the process of providing human beings with machinery capable of assisting them with the muscular requirements of work. ___________________________________________________________________________________________________ 2) A further development of mechanisation is represented by automation, which implies the use of control systems and information technologies to reduce the need for both physical and mental work to produce goods. ___________________________________________________________________________________________________ 3) In manufacturing, where the process began, automation has meant that the desired results can be obtained through a series of instructions made automatically by the system, which define the actions to be done. ___________________________________________________________________________________________________ 4) Numerical control over automated devices has resulted in a rapidly expanding range of applications and human activities. ___________________________________________________________________________________________________ 5) Computer-aided technologies (CAx) is a broad term that means the use of computer systems to aid in the design, analysis, and manufacture of products, by serving the basis for mathematical and organisational tools used to create complex systems. ___________________________________________________________________________________________________ 6) Thanks to the incredible improvements in automation technology, a number of other technologies have developed from it, such as domotics and robotics. ___________________________________________________________________________________________________ 7) Domotics is a field in building automation aimed at the application of automation technologies in households for the comfort and security of its residents. ___________________________________________________________________________________________________ Technical Terms domotics n. home robotics 家庭自动化，家庭智能系统 sensor n. a device that is used to record that something is present or that there are changes in something 传感器 transducer n. an electrical device that converts one form of energy into another 传感器，换 能器 Unit 8 Automation and Robotics 101 UNIT Engines 9 Learning Objectives Upon completion of the unit, students will be able to: . describe the function of the engine in the drive train system; . understand the working mechanism of the four-stroke engine; . compare different types of engine. Starting Off Why do you think a car or a train can run? In this unit, we will learn about this. Reading 1 Drive train The drive train is the system that makes a car move. It includes the engine, which burns fuel to produce the mechanical energy that moves the car, as well as the transmission, which changes the gear differential to use the power produced by the engine efficiently. It can also include the fuel system, which consists of the tank, various filters, fuel injectors or carburettors, the exhaust system which removes the engine’s waste products, the coolant system which prevents the engine from overheating, and the braking system which stops the car. Transmissions are either automatic or manual. Manual transmission involves a device, controlled by the driver, that transmits power to the wheels and it features mechanical gear sets that are engaged by the gear lever operated by the driver. Automatic transmission, on the other hand, requires no direct driver input once put into drive and leaves the operator free to focus on driving. Automatic transmission is now electronically controlled and integrated into the vehicle’s powertrain control system, which means the computer in the car decides when and what gear to shift into. The primary job of any transmission is to match engine speed to vehicle speed. Internal combustion engines produce useable power over a specific range of engine speed or rpm (revolutions per minute). The transmission is utilised to keep the engine in that sweet spot or rpm through the vehicle’s range of speeds. 1 Read the texts and complete the questions. 1) What is the main function of the drive train system? 2) What does a drive train system include? 3) What is the function of the engine? 4) What is the main function of the transmission once power is transmitted from the engine to the axle? 5) What are the main differences between manual and automatic transmissions? 6) What are the most important components of the chassis? Reading 2 The four-stroke engine Almost all cars currently use what is called a four-stroke combustion cycle (also known as the Otto cycle, from the name of its inventor Nikolaus Otto in 1876) to convert petrol into motion. The driving force behind the movement of a car is a device called an internal combustion engine. Within this engine, there is a constant cycle of ignition and combustion. Fuel is ignited by spark plugs, and it burns the air available to create an explosion. This cycle provides mechanical energy, which provides the power for the car. The main parts of the engine all work together to facilitate this process. The four strokes are: Engine Rear driveshaft Transfer case Prop shaft Front differential Front driveshaft Rear differential Transmission Fuel/air intake As the piston makes its way towards the high point of its motion, a mixture of fuel and air is injected into the cylinder through a carburettor or a fuel injection system. A proper mix of fuel with air enables the piston to function optimally. Compression As the piston nears the top of its up-and-down motion, it compresses the fuel and air that has been injected into the cylinder. Compression increases the explosiveness of a combustible material. Combustion/power At the moment that the piston hits the top of the cylinder, the fuel is ignited by a spark from a spark plug. The resulting combustion pushes the piston back down to the bottom of the cylinder. Exhaust Just as the heat and smoke from a fireplace fire has to be expelled through a chimney, the same is true of the combustion in an engine cylinder. When a car’s piston is propelled downward, the residue of the combustion is expelled through an exhaust valve in the cylinder wall and goes out through the exhaust pipe. Now the engine is ready for the next cycle, so it intakes another charge of air and gas. In an engine the linear movement of the pistons is converted into rotational motion by the crankshaft. The rotational motion makes the car’s wheels move. The area where compression and combustion take place is called the combustion chamber. The difference between the maximum and minimum volume of the combustion chamber is called displacement. 2 Read the text and rearrange the following sentences in the correct order 1–4. a As the piston returns to the top of its stroke, the intake valve closes and the mixture of air and fuel is compressed. b When a car piston is propelled downward, the residue of the combustion is expelled through an exhaust valve in the cylinder wall and goes out through the exhaust pipe. c A spark from a spark plug ignites the compressed gas. The resulting combustion pushes the piston back down to the bottom of the cylinder. d The piston starts at the top, the intake valve opens, and the piston moves down to let the engine take in air and fuel. 3 Look at the picture and translate the terms into Chinese. 1) intake valve ______________________ 2) connecting rod ______________________ 3) clutch ______________________ 4) flywheel ______________________ 5) piston ______________________ 6) exhaust cam ______________________ 7) gearbox ______________________ 8) exhaust valve ______________________ 9) intake cam ______________________ 10) crank(shaft) ______________________ 11) spark plug ______________________ Spark plug Exhaust cam Intake cam Exhaust valve Intake valve Clutch Piston Gearbox Connecting rod Flywheel Crank Reading 3 The two-stroke engine A two-stroke engine uses a mixture of fuel and oil as fuel. On the upstroke, the piston compresses the air/fuel mix in the combustion chamber. At the same time it pulls a fresh air/fuel mix into the crankcase for the next cycle. When the ignition sparks, it burns the mix forcing the piston downwards, opening the exhaust port while simultaneously forcing the air/fuel mix that was in the crankcase into the combustion chamber, as well as the spent exhaust out through the exhaust port. At this point it repeats the process. That is why fuel and oil are mixed together. The oil in the mix lubricates the motor. One of the main parts of a two-stroke engine is a crankcase that surrounds and protects all other parts of the engine. Inside, it has a crankshaft, connecting rod and single piston. It has also got an intake port, a reed valve, an exhaust port, and a cylinder—all in addition to the combustion chamber where the power is produced that moves whatever the engine is powering. The crankshaft in a two-stroke engine rotates, moving the piston by means of the connecting rod. These three parts are the only moving parts in a two-stroke engine. All power produced is a direct result of the action of these three moving parts. The connecting rod is connected to the crankshaft at one end, and to the piston at the other. It translates the movement of the crankshaft so that the piston is moved up and down. A two-stroke engine is commonly found in lower-power applications. Some of the devices that might have a two-stroke engine include garden equipment (lawnmowers, chainsaws, trimmers), dirt bikes, mopeds, jet skis, small outboard motors. The lower cost to rebuild and maintain made the two-stroke engine incredibly popular. Most small designs use petrol lubrication, with the oil being burned in the combustion chamber, causing “blue smoke” and other types of exhaust pollution. This is a major reason why two-stroke engines were replaced by four-stroke engines in many applications. 4 Read the text and decide if the statements below are true (T) or false (F). T F　　　　 1) A two-stroke engine is commonly found in higher power applications. 　　　　 2) One of the main reasons for the two-stroke engines loss of popularity was the fact that it caused blue smoke and other kinds of pollution. 　　　　 3) On the upstroke, the piston compresses the air/fuel mix in the combustion chamber. 　　　　 4) When the ignition sparks, it burns the mix forcing the piston up. 　　　　 5) Inside the crankcase there is a crankshaft, connecting rod and single piston and other components. 　　　 5 Read the text and rearrange the following sentences in the correct order 1–9. a When the piston reaches the top, b New fuel and air travel via the intake port into the cylinder, ready to be burnt. c the spark plug then lights the air/fuel mixture, burning it and sending the piston back down. d The piston is moved up and down inside the cylinder by the crankshaft, which is connected to it via the connecting rod. e The exhaust is expelled through the exhaust port, f A vacuum is formed as it takes its upward stroke, drawing air and fuel down through the reed valve. g and an unpleasant side effect is that it usually takes some of the unburned fuel mixture with it. h On the downward stroke, i the reed valve gets closed because of the increased pressure of the fuel and air mixture within, which is being compressed. 6 Match the words with their definitions. 1) fuel a the process of maintaining a fluid film between solid parts 2) pump b a machine or tool that does a special job 3) device c a substance such as oil or gas that can be burned to produce heat or energy 4) lubrication d a long piece of metal in a vehicle that is connected to the engine and helps to run the wheels 5) rod e a machine for forcing liquid or gas into or out of something 6) crankshaft f a long thin pole or stick 7) pollution g the process of making water, air, or land dangerous especially with poisonous chemicals Reading 4 The diesel engine In 1893 German inventor and mechanical engineer Rudolf Diesel invented the engine which still carries his name. The basic difference between a diesel engine or compression- ignition engine and a petrol engine is that a petrol engine needs an ignition system that uses an electric spark to be started. Diesel engines do not. In a diesel engine, the fuel is sprayed into the combustion chambers through fuel injector nozzles just when the air in each chamber has been placed under such great pressure that it is hot enough to ignite the fuel spontaneously. This is what happens when a diesel-powered vehicle is started. When the key in the ignition is turned a process begins in which fuel is injected into the cylinders under such high pressure that it heats the air in the cylinders all by itself. The time it takes to warm things up has been dramatically reduced—probably no more than 1.5 seconds in moderate weather. Diesel fuel is less volatile than petrol and it is easier to start if the combustion chamber is preheated, so manufacturers originally installed little glow plugs that worked off the battery to pre-warm the air in the cylinders when the engine was started. Better fuel management techniques and higher injection pressures now create enough heat to touch off the fuel without glow plugs, but the plugs are still in there for emissions control as the extra heat they provide helps burn the fuel more efficiently. Some vehicles still have these chambers whereas others do not, but the results are still the same. When there is pressure on the accelerator and the ignition key is turned to Start the fuel passes through a couple of fuel filters that clean it before it can get to the fuel injector nozzles. Proper filter maintenance is especially important in diesels because fuel contamination can clog up the tiny holes in the injector nozzles. A delivery tube keeps it under constant high pressure while it delivers the fuel to each cylinder at the proper time. Diesel engines are used in heavy equipment, locomotives, ships and vehicles. Gas engine Diesel engine 7 Read the texts about the diesel engine and choose the correct option. 1) A diesel engine A is very similar in build to a petrol engine. B is completely different in build to a petrol engine. C has more differences than similarities to a petrol engine. 2) The main difference between a diesel and a petrol engine is that A the diesel engine has spark plugs to ignite the fuel. B the diesel engine has no spark plugs to ignite the fuel. C the diesel engine has a mixed system to ignite the fuel. 3) In a diesel engine fuel is sprayed into the combustion chamber A at the end of the compression stroke. B before the compression stroke. C during the compression stroke. 4) Diesel fuel is A less volatile than petrol. B as volatile as petrol. C more volatile than petrol. 5) Filter maintenance in diesels is A as important as in petrol. B irrelevant. C more important than in petrol. 8 Read the text again and match the two parts of each sentence. 1) Turning the key begins a process a filters that clean it before it can get to the fuel injector nozzle. 2) The pressure of the fuel injection b can clog up the holes in the injector nozzles. 3) The fuel passes through a couple of c in which fuel is injected into the filters cylinders. 4) Fuel contamination d is so high that it heats the air in the cylinders all by itself. MY GLOSSARY differential n. 差速器；差额；差距 fuel injector 喷油嘴，燃料注入器 carburettor n. 汽化器，化油器（汽车发 动机部件） gear lever （车辆的）换挡杆，变速杆 powertrain 动力传动系统 utilize v. 利用，使用 sweet spot 最佳有效点；（球拍、球 棒等上的）最有效击打点 four-stroke adj. 四冲程的（内燃机） ignition n. 点火装置，点火器 spark n. 火花，火星；电火花 intake n. 吸入；（尤指）吸气 cylinder n. 圆柱体，圆柱状物；（发动 机的）汽缸 combustible adj. 易燃的，可燃的 expel v. 排出；驱逐 chimney n. 烟囱，烟道 linear adj. 线性的，线状的 displacement n. 排水量 crankcase n. 曲轴箱 lubricate v. 润滑 lawnmower n. 割草机 chainsaw n. 电锯 trimmer n. 修剪机 dirt bike 越野摩托车 moped n. 机动自行车 jet ski 摩托艇，水上摩托 outboard adj. 船外的；船侧的 diesel engine 柴油机，柴油引擎 nozzle n. 管嘴，喷嘴 moderate adj. 温和的，适度的 contamination n. 污染 clog up 堵塞 locomotive n. 火车头，机车 Unit 9 Engines 111 Listening 9 Listen to a mechanic talking about the differential and fill in the gaps to complete the passage. A differential is installed to allow a (1) _____________________ difference between the inboard and the outboard drive (2) _____________________. The components of a differential are a pinion (3) _____________________ driven by the transmission and the (4) _____________________, a ring gear driven by the pinion gear, and a set of spider gear driven by the ring gear. The action of the (5) _____________________ gears allows one wheel to spin faster or slower than the other as long as the average of the two speeds is the same as the speed of the (6) _____________________ gear. The differential has three tasks: . to aim the engine (7) _____________________ at the wheels; . to act as the final gear reduction in the vehicle, slowing the rotational speed of the (8) _____________________ final time before it hits the wheels; . to transmit the power to the wheels while allowing them to (9) _____________________ at different speeds. This is the one that earned the (10) _____________________ its name. 10 Listen to a description of the ignition process and then fill in the gaps with the missing words. When the car key turns the engine on, the (1) ____________________ from the battery travels to the starter and distributor. The (2) ______________ in the engine uses electric battery (3) ______________ to begin rotating the engine’s (4) _____________________. The electric battery power traveling to the distributor is distributed to all the spark (5) ______________ in the engine block. Once the starter begins to rotate the crankshaft, the (6) ______________ in the engine block begin to stroke up and down. When the piston goes down, a (7) ______________ injector mists a gas-and-oxygen mixture into the piston chamber. As the piston begins to travel back up, it compresses the gas and oxygen mix. At the top of the (8) ______________, the spark plug fires, and the small (9) _____________________ fires the piston back down and starts the crankshafts (10) _____________________ in a rotating motion. Speaking 11 Prepare a short presentation (2–5 minutes) of the following topics and then report to your classmates. . the combustion cycle . the four strokes . the ignition . the main difference between a petrol and a diesel engine Writing 12 Look at the picture of a two-stroke engine. What are the main differences in terms of components from the four-stroke one? Write a short paragraph. Combustion chamber Spark plug Piston Reed valve Exhaust outlet Crank case Fuel intake Fuel 13 Complete the text about biodiesel with the words from the box. engine exhaust fuel run oil peanut A diesel (1) _________________ can also run on vegetable (2) _________________ made from old cooking oil. This type of (3) _________________ is called biodiesel. Running a diesel engine on biodiesel fuel makes the (4) _________________ fumes smell like food. Using vegetable oil to (5) _________________ an engine is not a new idea. Incredible enough, the engine that Rudolf Diesel used to demonstrate his new idea ran on (6) _________________ oil. Translating 14 Translate the following sentences into Chinese. 1) The drive train is the system that makes a car move. It includes the engine, which burns fuel to produce the mechanical energy that moves the car, as well as the transmission, which changes the gear differential to use the power produced by the engine efficiently. ___________________________________________________________________________________________________ 2) Manual transmission involves a device, controlled by the driver, that transmits power to the wheels and it features mechanical gear sets that are engaged by the gear lever operated by the driver. ___________________________________________________________________________________________________ 3) Automatic transmission is now electronically controlled and integrated into the vehicle’s powertrain control system, which means the computer in the car decides when and what gear to shift into. ___________________________________________________________________________________________________ 4) Almost all cars currently use what is called a four-stroke combustion cycle (also known as the Otto cycle, from the name of its inventor Nikolaus Otto in 1876) to convert petrol into motion. ___________________________________________________________________________________________________ 5) The area where compression and combustion take place is called the combustion chamber. ___________________________________________________________________________________________________ 6) The connecting rod is connected to the crankshaft at one end, and to the piston at the other. It translates the movement of the crankshaft so that the piston is moved up and down. ___________________________________________________________________________________________________ 7) The basic difference between a diesel engine or compression-ignition engine and a petrol engine is that a petrol engine needs an ignition system that uses an electric spark to be started. Diesel engines do not. ___________________________________________________________________________________________________ 8) Diesel fuel is less volatile than petrol and it is easier to start if the combustion chamber is preheated, so manufacturers originally installed little glow plugs that worked off the battery to pre-warm the air in the cylinders when the engine was started. ___________________________________________________________________________________________________ Technical Terms exhaust system a system consisting of the parts of an engine through which burned gases or steam are discharged 排气系统 coolant system a cooling system that uses a fluid to transfer heat from one place to another 冷却系统 rpm n. rate of revolution of a motor 每分钟转数 piston n. a short, solid piece of metal that moves up and down inside a cylinder in an engine to press the fuel into a small space and to send the power produced by it to the wheels （发动机）活塞 upstroke n. a stroke normally made in an upward direction 上冲程 crankshaft n. a rotating shaft driven by (or driving) a crank 曲柄轴 clutch n. a pedal or lever that engages or disengages a rotating shaft and a driving mechanism 离合器 flywheel n. a heavy wheel in a machine that helps the machine to work at a regular speed 飞轮；惯性轮 gearbox n. a metal box containing the gears in a vehicle 变速箱，齿轮箱 accelerator n. the pedal in a car or other vehicle that you press with your foot to control the speed of the engine 油门，加速装置 Maintenance and Safety UNIT 10 Learning Objectives Upon completion of the unit, students will be able to: . know how to realise a proper maintenance; . understand the protective and precautionary measures for safety at work; . follow safety procedures at work. Starting Off When you fix something, what do you have to do to keep yourself safe? Please look it up and present it in class. Reading 1 Any machine and device must be controlled regularly in order to avoid the risk of damage or breakdown of single parts due to long usage. Sometimes, if a proper maintenance is not done, a fault could occur, with negative consequences on the production process and on the workers’ safety. The primary goal of maintenance is to avoid or mitigate the consequences of failure of equipment. This includes performing routine actions to keep the device in working order and prevent the failure before it actually occurs (preventive maintenance), or fixing equipment after breakdown (corrective maintenance). Preventive maintenance is designed to preserve and restore equipment reliability by replacing worn components before they actually fail. It includes maintenance activities such as partial or complete overhauls at specified periods, oil changes and lubrication. The ideal preventive maintenance is a combination of technical, administrative and managerial actions to prevent all equipment failure. If carried out properly, preventive maintenance can extend the life of the equipment. Corrective maintenance, sometimes simply called “repair”, is carried out to get equipment working again. It aims at restoring the functionality of a machine so that it can continue to perform its work. This type of maintenance can be very expensive because sometimes equipment needs to be replaced, with substantial costs for the company. Generally, maintenance is scheduled according to: the original equipment manufacturer’s recommendations; codes and legislation within a country; consultancy advice; previous maintenance; most important measured values and performance indications. 1 Answer the following questions according to the text. 1) Why is maintenance important? 2) What are the main types of maintenance? 3) What is the function of preventive maintenance? 4) Which activities does preventive maintenance include? 5) What is maintenance called if it occurs after a failure? 6) Why can corrective maintenance be expensive? 2 Read the text again and match the words with their definitions. 1) fault a damaged and in poor condition as a result of much use 2) mitigate b a set of rules about how something must be done 3) fix c expert advice within a particular field 4) overhaul d applying a greasy substance to reduce friction 5) worn e a break or other defect in a piece of machinery 6) lubrication f to do the necessary work to repair something that doesn’t work properly 7) code g to make something less severe or unpleasant 8) consultancy h a careful examination of a machinery or system that must be repaired 3 Look at the picture about the components of a car and label each part with a word or phrase in the box. seat battery radiator tyre spare wheel steering wheel disk brake oil filter trunk windshield wiper 1) 5) 3) 2) 4) 6) 7) 9) 8) 10) 4 In pairs, take this quiz about car maintenance, and then read the text in Exercise 5 to check your answers. Cars are not just a luxury item to purchase one day and forget about until something happens. A properly maintained car not only lasts longer, but it is also less likely to break down unexpectedly. Take this quiz and test your knowledge of car maintenance! 1) Auto maintenance doesn’t entail replacing fluids. True False 2) It is not possible to do preventive maintenance to cars. True False 3) Car maintenance must be scheduled keeping in mind different factors. True False 4) The distance travelled every day doesn’t affect the functionality of a car. True False 5) If a car is exposed to extreme weather conditions it must be checked more often. True False 6) It is not possible to replace windshield wipers. True False 7) Brake fluid lasts forever. True False 8) Car maintenance tasks should never be combined in one single service. True False 5 Read the text and match the correct maintenance task with each picture. Auto maintenance describes the act of inspecting or testing the condition of car subsystems (e.g.: engine, brakes, radiator, etc.) and replacing parts and fluids. Thanks to regular maintenance it is possible to ensure the safety, reliability and comfort of a car, while during preventive maintenance, a number of parts are replaced to avoid major damage or for safety reasons. Car maintenance is usually scheduled according to different factors, such as the year or model of the car, its driving condition and driver behaviour. When scheduling auto maintenance, car manufacturers recommend keeping in mind some factors that may affect the functionality of car subsystems. Some of these factors are: the number of trips and the distance travelled every day; the exposure to particular climate conditions (extreme hot or cold); long-distance cruising and whether the car has to tow a trailer or other heavy loads. Common car maintenance tasks include: car wash; check or replace the engine oil and oil filters; inspect or replace windshield wipers; inspect tyre pressure and wear; check wheel alignment; check, clean or replace battery terminals; inspect or replace brake pads and fluids; inspect or replace air filter; lubricate locks and hinges; check all lights; inspect or replace spark plugs; tighten chassis bolts. Some tasks that have equivalent service intervals can be combined into one single service known as a tune-up. In modern cars, where electronics control most of the car’s functions, the traditional tune-up has been replaced by incorporated software that takes care of the engine by constantly checking thousands of sensor signals. Completed maintenance services are then recorded in a service book which is very useful for keeping track of the car service history. 1) 2) 3) 4) 5) 6) 7) 8) Reading 2 Attention must be paid to safety in order to ensure a safe working practice in factories. Workers must be aware of the dangers and risks that exist all around them: two out of every three industrial accidents are caused by individual carelessness. In order to avoid or reduce accidents, both protective and precautionary measures must be followed while working. Each country has specific regulations concerning health and safety at work. For example, The Health and Safety at Work Act 1974 is a UK Act of Parliament that establishes the fundamental rules to enforce workplace health, safety and welfare within the United Kingdom. The objectives of the Act are: to secure the health, safety and welfare of people at work; to protect people in the work place against risks to health or safety in connection to their work activities; to control the keeping and use of dangerous substances; to control the emission of dangerous gases into the atmosphere. The Act defines general duties of employers, employees, suppliers of goods and substances for use at work, and people who manage and maintain work premises. In particular, every employer has to ensure the health, safety and welfare at work of all the employees, visitors, the general public and clients. Employers have to ensure the absence of risk to health in connection with the use, handling or storage of items and substances, as well as provide adequate facilities for a safe working environment. It is also very important to provide employees with proper instructions and training so that they will be able to cope with any problem that may occur at work. Employees, on their part, should always behave responsibly at work and take care of themselves and other people who may be affected by their actions. Moreover, they should cooperate with employers to enable them to perform their duties or requirements under the Act. 6 Answer the following questions according to the text. 1) Why is it important to ensure a safe working environment? 2) Which law regulates workers’ welfare in the United Kingdom? 3) What does the Act define? 4) What are the duties of employers? 5) Why is it important to provide employees with adequate training? 6) How can employees contribute to a safe working environment? 7 Read the text again and match the words and phrases with their definitions. 1) precautionary measure a a responsibility or task that you have to do as part of your job 2) carelessness b to deal effectively with a difficult situation 3) welfare c the buildings and land occupied by a business 4) duty d poor attention to an activity, which results in harm or errors 5) premises e action taken in order to prevent something dangerous from happening 6) cope with f the health, comfort and well-being of a person or group Unit 10 Maintenance and Safety 123 Reading 3 Safety signs and colours are useful tools to help protect the health and safety of employees and workplace visitors. Safety signs are used to draw attention to health and safety hazards, to point out hazards which may not be obvious and to remind employees where personal protective equipment must be worn. Colour attracts attention and can be used extensively for safety purposes. For example, colour can be used as an additional safety measure to identify the contents of pipes and the nature of the hazard. Different combinations of colours are used to indicate the various types of hazards. For example, the colour red is used to indicate a definite hazard, while a potential hazard is communicated by the colour yellow. When employees are aware of the hazards around them and take the necessary precautions, the possibility of an injury, illness or other loss is minimised. As shown in the table below, there are three basic sign categories used in the workplace: warning, to indicate definite or potential hazards; regulatory, to indicate which actions are prohibited or mandatory; information, to provide general information and directions. Each category is distinguished by its shape and can be divided into subcategories having different colours. 8 Read the text about safety signs and colours and complete the table with the correct sign category. Category Subcategory Colour 1) ________________________ A circle indicates that an order is in force. — Prohibition: it forbids an action. — Mandatory: it requires an action. Red and black on white White on black 2) ________________________ A triangle indicates caution or danger. — Caution: it indicates a potential hazard. — Danger: it indicates a definite hazard. Black on yellow White on red 3) ________________________ A square indicates information. — Emergency: it indicates first aid, health, fire protection and emergency equipment. — General information: it indicates permission or public information. White on green White on blue 9 Read the texts about safety equipment and match eath of the words and phrases in the box with the correct description. hearing protection hard hats respirator safety glasses face shield overall 10 Read the text about fire safety procedures and put the actions in the correct order. A fire safety plan is required in all public buildings, from schools, hospitals, supermarkets to workplaces. Generally, the owner of the building is responsible for the preparation of a fire safety plan. Once the plan has been approved by the Chief Fire Official, the owner is responsible for training all staff in their duties. Evacuation drills are a very important part of the staff training associated with emergency evacuation procedures. Drills should be carried out in all buildings at least once a year. The drill should be checked, recording the time required to complete the evacuation, and noting any problems and deficiencies. After each drill a meeting should be held to evaluate the success of the drill and to solve any problems that may have arisen. What to do in case of fire… If you see fire or smoke, do not panic. Remain calm and move quickly, but do not run. Alert the responsible staff and telephone the correct national emergency number. Have someone meet the firefighters to tell them where the fire is. They can lose valuable minutes if they have to find it themselves. Rescue any people in immediate danger only if it is safe to do so. If practicable, close all doors and windows to contain the fire. Try to extinguish the fire using appropriate firefighting equipment only if you are trained and it is safe to do so. Follow the instructions of your supervisor and prepare to evacuate if necessary. Save records if possible. Evacuate your area and check all rooms, especially changing rooms, toilets, storage areas, etc. Do a head count of all staff and report any people unaccounted for to the supervisor. a Close all doors and windows. b Do a head count of all staff and visitors. c Evacuate your area and check all rooms. d Meet the firefighters and give them details about the fire. e Save records. f Prepare to evacuate. g 1 Remain calm and move quickly. h Report any people unaccounted for to the supervisor. i Rescue any people in immediate danger. j Telephone the correct national emergency number. k Try to extinguish the fire using appropriate firefighting equipment. MY GLOSSARY mitigate v. 减轻，缓和 failure n. 故障；失败 worn adj. （因为长期使用）磨损 的，用坏的 overhaul n. & v. 彻底检修，大修；改造； 改进 lubrication n. 润滑；注油 aim at 旨在；瞄准 schedule v. & n. 安排 consultancy n. 咨询公司；顾问服务 behaviour n. 行为，举止 exposure n. 曝光；暴露 tow v. 拖，拉，牵引（车、船等） trailer n. 拖车，挂车 windshield n. （汽车等的）挡风玻璃 tyre n. 轮胎 wear n. 磨损，耗损，用旧 alignment n. 列队，排整齐 brake pad 刹车闸皮 hinge n. 合页，铰链 tighten v. （使）变紧，（使）紧固 chassis n. （车辆的）底盘 bolt n. （门窗上的）插销，闩 service book 服务手册 carelessness n. 粗心，疏忽，轻率 precautionary adj. 预防的；防备的，警惕的 employer n. 雇用者，雇主 employee n. 受雇者，雇员，员工 supplier n. （尤指长期的）供应商，提 供者，供应者 cope with （成功地）对付，应付，处 理 hazard n. 危险物，危害物 definite adj. 确定的；明显的 injury n. 伤害，损伤 mandatory adj. 强制的，义务的 Listening 11 Listen to the dialogue between Mrs Farrell and her mechanic and complete it with the missing words. Mechanic Good afternoon, Mrs Farrell. Mrs Farrell Good afternoon, John. How are you? Mechanic I’m fine, thank you. How can I (1) help you? Mrs Farrell Well, I need a complete (2) for my car. Next week my husband and I are going on holiday by car. It’s going to be a long journey all the way to Spain and I want my car to be in (3) . Machanic Sure. No problem. Have you checked your car recently? Mrs Farrell Let me think... It must have been last year, in June, when the car wouldn’t (4) . Anyway, it should all be written in the (5) . It’s in the glove compartment. Mechanic OK, I’ll take it. Let’s see... Oh, yes, it was the battery and I changed it. Are there any problems at the moment? Mrs Farrell Not really, but I think the (6) needs to be replaced. Mechanic Sure. I’ll check the filters too. Mrs Farrell Yes, I think it’s a good idea. Could you (7) the tyres as well? And maybe wash it; it’s so dirty. Well, John, when do you think the car will be ready? Mechanic Actually, I’m quite busy at the moment, Mrs Farrell, so I could give it back to you next Friday. Would that be convenient for you? Mrs Farrell Yes, it’d be perfect, because we’re leaving on Sunday. I’ll call you on Tuesday for a confirmation then. Mechanic All right. Goodbye, Mrs Farrell. on Friday... Mechanic Good morning, Mrs Farrell. Here are your keys. I replaced the engine oil and the (8) . Then I checked the tyres and the brakes too. I had to (9) the spark plugs because they were fouled. I also (10) the electronics and then I washed the car. Now everything is OK, you can set off with no worries. Mrs Farrell That’s great! Thank you very much, John. 12 This is an example of safety rules established by the workers’ safety committee in a factory in Adelaide, Australia. Read the text and complete it with the words and phrases in the box. Then listen and check. operate tidy fire gloves concentration first aid protection brush SAFETY RULES MACHINERY Be sure to understand how to (1) operate every machine you are going to use. Never use machinery when you are in a room alone. Use all the (2) required in the place of work. Check that the safety devices are working. If they are not working, ask for them to be repaired immediately. Do not talk to anybody who is operating a machine. (3) is important at all times. Turn off the electricity before cleaning a machine. TOOLS Report any damage to the tools used at work. See that tools are correctly set. DRESS Before starting work, wear protective clothing. Always wear safety glasses, (4) and boots when using a machine. WORKSHOP Keep the workshop (5) , do not leave rubbish around and do not throw cigarette ends or ashes into the rubbish bin. The area around machines must be kept clear to avoid falling. Tools and protective clothing should be put away when not in use. Clean machines after use with a (6) not with your hands. ACCIDENT PROCEDURES Make sure you know where to assemble in the event of (7) and where the emergency stop buttons are located. Check where the fire extinguishers are in your workplace and how they work, in order to be able to use them in case of fire. Do not shout or run as this can lead to panic, and inform the supervisor immediately if any accident occurs. Never administer (8) unless you have been trained to do so. 13 Read the text in Exercise 12 again and decide if the following rules are true (T) or false (F). Then correct the false ones. T F　　　　 1) Use machinery only when other people are in the workplace. 　　　　 2) People mustn’t talk in the workplace. 　　　　 3) Turn off electricity after a machine has been cleaned. 　　　　 4) Wear safety boots before arriving in a workplace. 　　　　 5) Always wear sunglasses when using a machine. 　　　　 6) Damaged tools can be dangerous. 　　　　 7) Report to the supervisor about damaged equipment. 　　　　 8) In case of fire ask the supervisor where the emergency stop buttons are located. 　　　　 9) In case of fire shout to catch other people’s attention. 　　　　 10) Anyone can give first aid in case of an accident. 　　　　 Speaking 14 Discuss the auto maintenance and tell your partner how to take safety measures. Writing 15 Write a summary about safety rules when working. Some signs are listed as follows (you may match them with their meanings). Use them for your help. a slippery when wet b high voltage c first aid station d head protection must be worn e ionising radiation f no smoking area 1 3 2 4 5 6 Translating 16 Translate the following sentences into Chinese. 1) Any machine and device must be controlled regularly in order to avoid the risk of damage or breakdown of single parts due to long usage. ___________________________________________________________________________________________________ 2) The primary goal of maintenance is to avoid or mitigate the consequences of failure of equipment. ___________________________________________________________________________________________________ 3) Preventive maintenance is designed to preserve and restore equipment reliability by replacing worn components before they actually fail. ___________________________________________________________________________________________________ 4) Corrective maintenance, sometimes simply called “repair”, is carried out to get equipment working again. ___________________________________________________________________________________________________ 5) Thanks to regular maintenance it is possible to ensure the safety, reliability and comfort of a car, while during preventive maintenance, a number of parts are replaced to avoid major damage or for safety reasons. ___________________________________________________________________________________________________ 6) Completed maintenance services are then recorded in a service book which is very useful for keeping track of the car service history. ___________________________________________________________________________________________________ 7) Attention must be paid to safety in order to ensure a safe working practice in factories. ___________________________________________________________________________________________________ Technical Terms radiator n. a device for cooling the engine of a vehicle or an aircraft （车辆或飞机发动 机的）冷却器，水箱 steering wheel the wheel that the driver turns to control the direction that a vehicle goes in 方向盘；舵轮 oil filter a filter that removes impurities from the oil used to lubricate an internal- combustion engine 滤油器，机油滤清器 windshield wiper a mechanical device that cleans the windshield 雨刷