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The Architecture Concept Book: An inspirational guide to creative ideas, strategies and practices. The Art of Electronics - third Edition. The Badges of Kitchener's Army. The Country House Library. The Lean Product Lifecycle: A playbook for making products people want. The Nazi Hunters. The Six Sigma Handbook, 5E. It is the friction force, F, acting up the slope, that stops itslidingdown. Reading 2 Grammar links in texts One of the ways in which sentencesin a text are held together is by grammar links.
In this extract, note how each expression in italics l i d s with an earlier expression. Another very important force in engineering is theonecaused by elasticity. Agood example of this is a spring. Springs exert more force the more theyare stretched.
This property provides a way of measuringforce. Sometimes these links cause problems for readers because they cannot make the right connection between words in different parts of a text.
Study these common grammar links: 1 A repeated noun becomes a pronoun. Springs becomes they. Force in engineering becomes one. Springs exert moreforce the more they are stretched becomes This property.
Join them as in the example above. Friction in machines is destructive and wasteful. Itcauses the moving parts to wear and it produces heat where it is not wanted.
They also use ball 5 bearings and roller bearings because rolling objects cause less friction than sliding ones. Source: S. Larkin and L. Bernbaum eds. The Penauin Bookof the Physical World. I Horizontallv calibrated Fig.
When we describe this experiment, we write: A block of wood is placed on a flat surface. A spring balance is attached to one end of the block. This description uses the present passive. Task 5 Complete this description of the experiment using the present passive. A block of wood ' on a flat surface. A spring balance " to one end of the block. A gradually increasing force to the balance.
The force at which the block just begins to move- 4 The block along at a steady speed. The force required to maintain movement. It is found that the first force is greater than the second. What does this experiment show? Listening Listening to lectures The listening passage you are going to hear is an extract from a typical engineering lecture. Here are some of the features of lectures. For example: Now what I thought Imight do today What wearegoing to talkof For example: It will turn, revolve.
For example: What we are going to talk ojis the extension ofajorce. Task 6 In the same way as when reading, it is helpful to think about the topic of a lecture before you listen. The topii here is The Moment of a Force. Can you explain the links between these words from the lecture and the topic? Use a dictionary to help you if necessary.
Which of the words in Task 6 can be used to talk about the diagram? What do you think the lecturer is indicating each time? Select from the labels below, a to e. All right? The electric motor Task 1 Working in your group, list as many items as you can in the home which use electric motors. Which room has the most items? Reading Skimming In Unit 3 you studied scanning - locating specfic information quickly.
Another useful strategy is reading a text quickly to get a general idea of the kind of information it contains. You can then decide which parts of the text are worth reading in more detail later, depending on your reading purpose. This strategy is called skimming. Task 2 Skim this text and identify the paragraphs which contain information on each of these topics. The 6rst one has been done for you.
This can drive all sorts of machines, from wrist-watches to trains. The motor shown in Fig. It is a universal motor, which can run on direct current or 5 alternating current. An electric current running through a wire produces a magnetic field around the wire.
If an electric current flows around a loop of wire with a bar of iron through it, the iron becomes magnetized. It is! If you put two magnets close together, like poles-for example, 3 - two north poles repel each other, and unlike poles attract each other. When electricity flows around the armature wire, the iron becomes an electromagnet. I The attraction and repulsion between the poles of this armature magnet and the poles of the field magnet makethe armature turn.
As a result, its north pole is close to the south pole of the field maunet. Then the current is reversed so the north w l e of the armature magnet becomes the south pole. Once again, the attraction and repulsion between it and the field magnet make it turn. The armature continues turning as long as the direction of the current, and therefore its magnetic poles, keeps being reversed. To reversethe direction of the current, the ends of the armature t wire are connected to different halves of a solit rino called a I commutator.
Current flows to and from the kmm;tatorthrough small carbon blocks called brushes. As the armature turns, first one half of the commutator comes into contact with the brush delivering the current, and thenthe other, so the direction of the current keeps being reversed. B, C, or D. One of the descriptions does not match any of the diagrams. The diagrams are in the correct sequence, but the descriptions are not. Motor run on direcl current A The armature turns a quarter of a turn.
Then electric contact is broken because of the gap in the commutator, but the armature keeps turning because there is nothing to stop it. B When current flows, the armature becomes an electromagnet. Its north pole is attracted by the south pole and repelled by the north pole of the field magnet. C When a universal motor is run on direct current, the magnetic poles in the armature change while those of the field magnet remain constant.
D When the commutator comes back into contact with the brushes, current flows through the armature in the opposite direction. Its poles are reversed and the turn continues. Language study Describingfunction Try to answer this question: What does an electric motor do? When we answer a question like this, we describe the function of something. We can describe the function of an electric motor in this way: An electric motor converts electrical energy to mechanical energy.
We can emphasize the function like this: Thejunction ofan electric motor is to convert electrical energy to mechanical energy. Task 4 Match each of these motor components to its function, and then describe its function in a sentence. Component Function 1 armature a transfers rotation from the motor 2 bearings b create an electromagnetic field 3 brushes c converts electromagnetic energy to rotation 4 commutator d reverses the current to the armature 5 drive shaft e support the drive shaft 6 field windings f supply current to the armature Writing Describing components Task 5 Dismantle this simple dc motor into its components by completing the labelling of the chart below.
A simple dc motor consists ofa field magnet and an armature. The armature is placed between the poles of the magnet. The armature is made up of a loop of wire and a split ring known as a commutator. The loop is connected to the commutator. Current is supplied to the motor through carbon blocks called brushes.
To write a description, you need to use language to: 1 dismantle a piece of equipment into its main parts. These expressions will help: consists of X A A ismadeupof XandY is composed of Y 2 name components: Carbon blocks known as called brushes. Task 6 Complete the text with the help of the diagram on the next page. Use the following words: are made up is placed is composed consists A transformer of two coils, a primary and a secondary.
The coils are wound on a former which is mounted on a core. The coils of a number of loops of wire. The core of thin pieces of soft iron. U- and T-shaped pieces are used. The former on the leg of the T. Now label the diagram opposite using the completed text. Word study Study these expressions for describing how componentsare connected to each other.
A is bolted to B. A is welded to B. A is tixed to B. Task 2 Find out what these terms mean in education. Use a dictiooary if necessary. It also helps to think about what you will hear before you listen. Tbt nut two tasks will help you to prepare for listening and to have a dearpurpose. Task 3 You are going to hear an interview with David, a student of electrical engineering at a Scottish college of further education.
He is a mature student with previous service in the Navy. Here is David's weekly timetable. Some of the information is missing. Before you listen, try to answer these questions about the timetable. Answer these questions. Compare your answers with a partner. Part 1 What is the name of David's course? How long is the course? How old is David? How long was he in the Navy? How many types of submarines are there? Part 2 How many weeks of teaching does he have left? How is the course assessed?
What happens if you fail the tests once? How many are in his class? What kind of problems has he had? Task 6 D Listen to Part 3 of the interview. Try to complete the information missing from the timetable. Task 8 Liiten to the last part of the interview. Part 4 11 When does he practise sport? Task 7 D Now listen to the whole tape. Answer these more difficult questions.
Writing Comparing and contrasting Task 8 Write your own timetable in English. Note any similarities and differences between David's week and your own. Central heating Task 1 How can you heat a house in cold weather? List the possible ways Reading Predicting In Unit 5 we learnt how using the title can help us to predict the contents of a text.
Diagrams are also very useful in helping the reader to make the right guesses about what a text will contain. Before you read a text. You mav not find all the information vou want. Gas central heating 5 Most gas central heating works on the 'wet' system of heat transfer between water flowing through pipes. Atypical system includes a boiler, a network of pipes, a feed, and expansion tank, radiators, and a hot water storage system.
In conventional boilers, water is heated by gas burners. It is then I pumped around the central heating system and the hot water storage cylinder. The flow of gas to the burner is controlled by a valve or valves which can be operated by a time switch or by a boiler thermostat, hot water cylinder thermostat, or by a ro thermostat located in one of the rooms.
Air is necessary for complete combustion and is supplied to the burners either from inside the house, when adequate ventilation must beensured, or directly from outsidethrough a balancedflue.
Water is circulated through a heat exchanger above the burner. The i s heat exchanger is made of tubes of cast iron or copper, which resist corrosion. Both types use fins to increasethe surface area in contact with water, which improves the transfer of heat. A thermostat located in the boiler causes the gas control valve to shut off when the watertemperature reaches the pre-set level. One loop passesthrough the inside of the hot water storage cylinder in a coil arrangement.
Heat is transferred to the surrounding water, which can then be drawn off from this 25 cylinder from various hot taps in the house when required. The loopthen returnsto the boiler for re-heating. The other loop of the circuit passesto the radiators, which provide room heating. Several radiators are generally connected, where one pipe provides the hot water input and the other carries the cold 30 water back to the boiler. In this wav, all radiators receive hot water directly from the boiler.
The first and last have been done for you. Water is circulated through a heat exchanger. I The loop returns to the boiler for re-heating. One loop passes through the inside of the hot water storage cylinder in a coil of pipes. The hot water is pumped through a diverter valve. The other loop of the circuit passes to the radiators. Cold water from the radiators returns to the boiler. Use the statements in Task 4 to label the stages shown in this diagram of a heating system.
Fira flwr Ground floor t 1 Language study Time clauses What is the relationship between these pairs of actions? How can we link each pair to show this relationship? The water is heated.
It reaches a pre-set temperature. It is pumped to a diverter valve. The gas control valve shuts off. We can show how actions are linked in time by using time clauses. We can use as to link two connected actions happening at the same time. For example: 1 As cold waterpasses through a heat exchanger, the water is heated. We can use until to link an action and the limit of that action. For example: 2 The water is heateduntil it reaches apre-set temperature. Note that until normally comes between the stages.
We can use after to show that one action is followed by another action. For example: 3 qftcr the water is heated, it is pumped to a diverter valve. We can use when to show that one action happens immediately after another.
For example: 4 When the water temperature reaches the right level, thegas control valve shuts off. Note that when the time word comes h t in the sentence. Task 6 Link these sets of actions with appropriate time words. Cold water passes through a heat exchanger in the boiler. The water becomes hotter and hotter.
The water reaches a pre-set level. The water temperature reaches the pre-set level. A thermostat causes the gas control valve to shut off. The water is pumped to a diverter valve. The water goes to the hot water cylinder or the radiators. Hot water passes through the inside of the hot water storage cylinder in a coil arrangement.
Heat is transferred to the surrounding water. The hot water flows through the radiators. The hot water loses heat. The water passes through the radiators. The water returns to the boiler. Word study Task 7 The words listed in the fust column of this table are common in descriptions of technical plant.
They describe how substances are moved from one stage of the process to the next. Some of these words can be used for any substance: others are more specsc. Write an X under Solids, Liquids, or Gases if the word on the left can be used to talk about them.
The k s t example has been done for you. Match each label to the correct warning. Task 2 List some of the potential dangers in your laboratory, workshop, or place of work. How is the risk of these hazards reduced? Task 3 Study the safety instructions from a workshop below, and then answer these questions. I 1 2 Wear protective clothing at all times. Always wear eye protection whenoperating I lathes, cutters, and grinders and ensure the guard is in place.
Tools should be put away when not in use and I I any breakages and losses reported 1 6 Machines should be cleaned after use, Reading Understanding the writer'spurpose Knowing what the writer's purpose is, who the writer is, and who the intended readers are can help us to understand a text. The safety instructions in Task 3 are clearly intended to encourage employees to be safety conscious and reduce the risk of accidents.
The writer is perhaps a supervisor or the company safety officer, and the intended readers are machine operatives. Knowing these things can help us to work out the meaning of any part of the text we may not understand. Task 4 Study the company document on safety on the next page, and then answer these questions.
A written preliminary investigation will be completed by the end of the particular shift or business day on which the accident occurred. In no event should there be a delay of more than 24 hours. Failure to comply with this requirement may subject the immediate manager to disciplinary action up to and including discharge.
Without adequate accident investigation data the Company may be subjected to costs, claims, and legal action for which it has no defence. As a minimum, the preliminary accident investigation report will include the following: 1 Name, occupation, and sex of injured worker. The employee who was injured and any employee s who witnessed the incident should be separately interviewed as soon as possible.
A copy of the report must be submitted to the Manager - Human Resources for review. Another copy of the report is to be retained for a period of not less than the injured employee's length of employment plus five 5 years.
Task 5 Study this brief report of an accident. In which points does it not meet company policy on reporting accidents?
Language study Making safety rules What are the differences in meaning, if any, between these statements? We can make safety rules in these ways: 1 Using an imperative. Wear protective clothing. Do not wear loose-fitting clothing.
Never wear loose-fitting clothing. Protective clothing should be worn. Task 6 Study this list of unsafe environmental conditions hazards. Write safety rules to limit these hazards using the methods given above. For example: inadequate lighting Lighting must be adequate. We learnt how to mark reasons, results, and contrasts in our writing. What are the links between these ideas? Sentence 3 is an additional reason.
We can mark the links between them like this: The accident happened because of the operator's carelessness. We use because of to introduce a reason which is a noun or noun phrase. We use in addition and moreover to introduce an additional reason. Sentence 5 is an example to illustrate sentence 4. We can mark this in this way: Suitableprotection should be worn. Task 7 Show the links between these sets of ideas using appropriate linking woru.
Workers' carelessness. It is important that all workers receive training in basic safety. Goggles must be worn for grinding and cutting. They prevent burns. They reduce the danger of cuts. They prevent the feet getting caught in machinery. Dust can damage the lungs. Each year people are injured. They refuse or forget to wear the right gear. Study this diagram of her invention. Discuss these questions in your group: 1 What is it? Listening Task 2 m Now Listen to Lucy talking about her invention and career plans.
As you listen, check your answers to Task 1. Task 3 rn Now listen again. Here are some of the things Lucy talks about. Put them in the correct sequence. The first one has been done for you. Task 4 Now make notes on what Lucy says about the above topics. Task 5 Label the diagram in Task 1with these terms: 1 rope 2 handle 3 pulley 4 A-frames 5 cross-piece 6 seat Task 6 Put these steps in the creation and development of the swing in the correct sequence. Writing Describing and explaining Task 8 You are going to write a brief description and explanation of Lucy's invention.
It will consist of two paragraphs. Paragraph I Use the labelled diagram in Task 1and the information from the tape to write a brief description of Lucy's invention. Your description should answer these questions: 1 What is it called? Paragraph 2 The following steps explain how the swing works. Then use so and when to link them into a paragraph. The rope pulls the seat forwards. Repetition of these actions causes a swinging motion.
The child puUs down on the handle. The seat swings back under the weight of the child. The child releases the handle. Speaking practice Task 9 Work in pairs. A and B. Student A: Play the part of the interviewer. Base your questions on the topics in Task 3, and any other questions you may wish to add.
For example: a Her career plans. Student B: Play the part of the swing inventor. Conduct the interview. Washing machine Task 1 Many items found in the home contain control systems. The washing machine is one of the most complex. List some of the factors the control system of a washing machine must handle. This diagram may help you. They can also help you to understand the accompanying text. For this reason, it is helpful to try to understand any diagram before reading the text.
Task 2 Study the diagram again. Try to explain the function of each of these items. For example, you can control the volume of a TV by using a remote control. The building blocks of a control system are: Input -t Press bumn Signal is Volume on remote wntrol sent to TV is adjusted Theinput can be any movement or any change in the environment.
The control may change the size of the output for example, adjustingthe sound of a N. Often this involves changing one kind of input into a different kind of output. For example, opening a l o window may set off a burglar alarm.
Outputscan be of many kinds. An alarm system may ring a bell, flash lights, and send a telephone messageto the police. Most control systems are closed loops. That means they incorporate a way of checking that the output is correct.
In other 15 words, they have feedback. The thermostat in a central heating system Fig. These are door position, water level, water temperature, wash and spin times, and drum speeds. YOU can see that this is quite a complex closed loop system using feedbackto keep a check on water level, water temperature, and 25 drum speeds.
It receives and sends signals which control all the activities of the machine. It is alsc capable of diagnosing faults which may occur, stopping the program, and informing the service engineer what is wrong. It i 30 small, dedicated computer which, like other computers, uses th language of logic. Source: P.
Fowler and M. When the door is closed, it completes an electrical circuit which heats up a heat-sensitive pellet. This expands as it gets hot, pushing a mechanical lock into place and closing a switch. The switch signals the control unit that the door is closed and locked. StudentA: Read Texts 2 and 3. Student B: Read Texts 4 and 5. Complete your section of the table opposite.
Then exchange information with your partner to complete the whole table. Control factor Operating device Feedbackby 1 Door position heat-sensitive pellet switch 2 Water level 3 Water temperature 4 Wash and spin times - 5 Drumspeeds Text 2 Water Ieval When a wash program first starts it has to open the valves which allow the water in.
There are usually two of these valves, one for hot water and one for cold. Each must be controlled separately depending on the water temperature needed forthat program. The 5 valves are solenoid operated, i. The rising water level is checked by the water level sensor. This is a pressure sensor. The pressure of the air in the plastic tube rises as it is compressed by the rising water. The pressure sensor keeps the 10 control unit informed as to the Dressure reached and the control unit uses the information to decide when to close the water inlet valves.
Water temperature The temperature sensor, a type of thermometer which fits inside the washer drum, measuresthe water temperature and signals it to the control unit. The control unit compares it with the temperature nwded forthe program being used. If the water temperature is too 5 low, the control unit will switch on the heater.
The temperature sensor continues to check the temperature and keep the control unit informed. Once the correct temperature is reached, the control unit switches off the heater and moves on to the next stage of the program. Text 4 Clock The control unit includes a memorywhich tells it how long staae of a Droaram should last. The times mav be different he electronic clock built into the control unit keeps th memory of the control unit informed so that each stage of each 6 program is timed correctly.
The motor starts up slowly, then gradually increasesspeed. The spee sensor, a tachogenerator, keeps the control unit informed as to speed that has been reached. The control unit uses the informat to control the power to the motor and so controls the speed of the l o drum at all times. Sensor Condition Control unit action Water level low open inlet valves level high enough Water temperature switch on heater high enough Drum speed decrease motor speed The conditions which the sensors report determine the action of the control unit.
We can link each condition and action like this: If the water level is low, the inlet valves are opened. Task 6 Write similar sentences for the other five conditions given. Now study this example: Sensor Condition Control unit action Door Door open Machine cannot start Door closed Machine can start We can link these conditions and actions as follows: 1 u t h e door is open, the machine cannot start.
We use unless when an action cannot or will not happen if a prior condition is not true. In example 3. Unless means If A Dictionary of Mechanical Engineering 1 ed. Over 7, entries This new Dictionary provides definitions and explanations for mechanical engineering terms in the core areas of design, stress analysis, dynamics and vibrations, thermodynamics, and fluid mechanics, in over 7, clear and concise A to Z entries, many illustrated.
Read More. Your current browser may not support copying via this button. All Contents Entries. Items per page: 10 Front Matter Publishing Information Preface. A-Z to view, select the "Entries" tab. All rights reserved.
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