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Tài liệu Tiếng Anh Chuyên ngành Cơ điện được biên soạn theo chương trình đào tạo nghề môn tiếng Anh chuyên ngành Công nghệ thông tin của Trường cao đẳng công nghệ thành phố Hồ Chí Minh. Tài liệu được viết theo các chủ đề liên quan đến ngành công nghệ thông tin. Cấu trúc tài liệu gồm 6 bài. Mỗi bài có 3 phần: Tasks, language work, reading comprehension. Mời các bạn cùng tham khảo.
TẬP ĐỒN DỆT MAY VIỆT NAM TRƯỜNG CAO ĐẲNG CƠNG NGHỆ TP HCM TÀI LIỆU GIẢNG DẠY MÔN HỌC/MÔ ĐUN: TACN CƠ ĐIỆN NGÀNH/NGHỀ: CNKT CƠ KHÍ, ĐIỆN TỬ TRÌNH ĐỘ: CAO ĐẲNG/ TRUNG CẤP …………, năm 2019 TUYÊN BỐ BẢN QUYỀN Tài liệu thuộc loại tài liệu giảng dạy nội sử dụng nhà trường với mục đích làm tài liệu giảng dạy cho giảng viên sinh viên nên nguồn thơng tin tham khảo Mọi mục đích khác mang tính lệch lạc sử dụng với mục đích kinh doanh thiếu lành mạnh bị nghiêm cấm LỜI GIỚI THIỆU Tài liệu biên soạn theo chương trình đào tạo nghề môn tiếng Anh chuyên ngành Công nghệ thông tin Trường cao đẳng cơng nghệ thành phố Hồ Chí Minh Tài liệu viết theo chủ đề liên quan đến ngành công nghệ thông tin Cấu trúc tài liệu gồm Mỗi có phần: Tasks, language work, reading comprehension Trong trình biên soạn, có nhiều cố gắng khơng tránh khỏi hạn chế thiếu sót định, Tổ môn Ngoại ngữ mong nhận ý kiến đóng góp q đọc giả để giáo trình ngày hoàn thiện Xin chân thành cảm ơn! TP HCM, ngày……tháng năm 2019 Tham gia biên soạn Hồng Thị Minh Nhựt CHƯƠNG TRÌNH MƠN HỌC Tên mơn học: TIẾNG ANH CHUN NGÀNH Mã mơn học: Thịi gian thực môn học: 45 giờ; (Lý thuyết: 42 giờ; Thực hành, thí nghiệm, thảo luận, tập: giờ; Kiểm tra: giờ) I Vị trí, tính chất mơn học: - Vị trí: Mơn học phân bố vào học kỳ 4, sau môn học Tiếng Anh Tiếng Anh - Tính chất: Là môn học chuyên môn ngành, nghề II Mục tiêu môn học: Sau học xong môn học này, sinh viên đạt được: Về kiến thức: - Hiểu sử dụng từ vựng chuyên ngành điện: khái niệm ngành kỹ thuật, định nghĩa dòng điện, thiết bị điện bản; - Trình bày động từ đơn, tiếp diễn, hoàn thành, khứ đơn, khứ tiếp diễn, tương lai gần, tương lai đơn, tính từ so sánh, mệnh đề liên hệ, dạng câu điều kiện, câu bị động, cấu trúc đặc biệt thường sử dụng kỹ thuật Về kỹ năng: - Hình thành phát triển khả giao tiếp, đọc hiểu dịch thuật tài liệu chuyên ngành điện với việc sử dụng từ điển; - Tự tìm kiếm, tự học nghiên cứu tài liệu Về lực tự chủ trách nhiệm: - Nhận thức ý nghĩa tầm quan trọng môn học; - Rèn luyện kĩ nghe, nói, đọc, viết làm việc nhóm; - Rèn tính tự tin, phương pháp học tư duy, phát huy tính tích cực, chủ động sáng tạo học tập III Nội dung môn học: Nội dung tổng quát phân bổ thời gian: Thời gian (giờ) Số Thực hành, thí Tên chương, mục Tổng Lý Kiểm TT nghiệm, thảo số thuyết tra luận, tập Unit 1: Engineering – What 7 is it about? Unit 2: Using electricity – 7 Electrical engineering 5 Achievement test Unit 3: Charges in motion Unit 4: Electrical motors Achievement test Unit 5: Circuit breakers Unit 6: Refrigerators Achievement test Cộng 7 7 45 7 7 42 Nội dung chi tiết: Unit 1: Engineering – What is it about? Thời gian: Mục tiêu: Sau học xong này, sinh viên đạt được: - Hiểu sử dụng từ vựng ngành kỹ thuật; trình bày thành thạo cách sử dụng thể bị động tại, giới từ câu điều kiện loại một; - Đọc, dịch giao tiếp cách ngành kỹ thuật; - Phát huy ý thức tham gia hoạt động nhóm, thảo luận trao đổi kinh nghiệm tìm phương pháp học tập tích cực chủ động Nội dung bài: 2.1 Vocabulary Thời gian: 2.1.1 Some definitions and conceptions of engineering 2.1.2 Practice the conversation 2.2 Grammar Thời gian: 2.2.1 The simple present passive 2.2.2 Prepositions: with, of, about, for 2.2.3 The first conditional sentence 2.3 Practice doing exercises Thời gian: 2.3.1 Practice reading the text about some concepts of engineering 2.3.2 Practice translating the text about some concepts of engineering 2.3.3 Doing the exercises Unit 2: Using electricity – Electrical engineering Thời gian: Mục tiêu: Sau học xong này, sinh viên đạt được: - Hiểu sử dụng từ vựng kỹ thuật điện, công dụng điện đời sống hàng ngày; trình bày thành thạo cách sử dụng thể bị động động từ khiếm khuyết, q khứ hồng thành; sử dụng Will để diễn tả kế hoạch tương lai, lời đề nghị lời hứa; - Đọc, dịch giao tiếp cách ngành kỹ thuật, lượng điện sử dụng đời sống; - Phát huy ý thức tham gia hoạt động nhóm, thảo luận trao đổi kinh nghiệm tìm phương pháp học tập tích cực chủ động Nội dung bài: 2.1 Vocabulary Thời gian: 2.1.1 Usefulness of electricity; electrical engineering 2.1.2 Practice the conversation 2.2 Grammar Thời gian: 2.2.1 The passive voice of modal verbs 2.2.2 The simple past passive and present perfect passive 2.2.3 Using will to express future plan, intention; an offer or a promise 2.3 Practice Thời gian: 2.3.1 Practice reading the text about using electricity in everyday life 2.3.2 Practice translating the text about using electricity in every life 2.3.3 Doing the exercises Achievement test Thời gian: Unit 3: Charges in motion Thời gian: Mục tiêu: Sau học xong này, sinh viên đạt được: - Hiểu sử dụng từ vựng khái niệm điện tích, dịng diện, chất dẫn điện, điện trở; trình bày khác biệt mệnh đề liên hệ xác định không xác định - Đọc, dịch giao tiếp cách ý nghĩa dòng điện, chất dẫn điện trở - Phát huy ý thức tham gia hoạt động nhóm, thảo luận trao đổi kinh nghiệm tìm phương pháp học tập tích cực chủ động Nội dung bài: 2.1 Vocabulary Thời gian: 2.1.1 Some definitions and conceptions of electrical currency; charges in motion 2.1.2 Practice the conversation 2.2 Grammar Thời gian: 2.2.1 Present participle phrases 2.2.2 Past participle phrases 2.3 Practice Thời gian: 2.3.1 Practice reading the text about meaning of electric current; conductivity and resistance 2.3.2 Practice translating the text about meaning of electric current; conductivity and resistance 2.3.3 Doing the exercises Unit 4: Electrical motors Thời gian: Mục tiêu: Sau học xong này, sinh viên đạt được: - Hiểu sử dụng từ vựng số khái niệm công dụng động điện, nguyên tắc vận hành động điện, trình bày khác biệt mệnh đề liên hệ xác định không xác định; - Đọc, dịch giao tiếp cách công dụng động điện, nguyên tắc vận hành; - Phát huy ý thức tham gia hoạt động nhóm, thảo luận trao đổi kinh nghiệm tìm phương pháp học tập tích cực chủ động Nội dung bài: 2.1 Vocabulary Thời gian: 2.1.1 Subjects for the engineering studies; usefulness of electric motors; principle of operating electric motors 2.1.2 Practice the conversation 2.2 Grammar Thời gian: 2.2.1 Non - defining relative clauses 2.2.2 Differences between defining relative clause and non - defining relative clause 2.3 Practice doing exercises Thời gian: 2.3.1 Practice reading the text about principle of operating electric motors 2.3.2 Practice translating the text about principle of operating electric motors 2.3.3 Doing the exercises Achievement test Thời gian: Unit 5: Circuit breakers Thời gian: Mục tiêu: Sau học xong này, sinh viên đạt được: - Hiểu sử dụng từ vựng số khái niệm công dụng ngắt điện, loại ngắt điện phổ biến, trình bày thành thạo dạng so sánh với tính từ, danh từ; - Đọc, dịch giao tiếp cách công dụng ngặt điện loại ngắt điện thông dụng; - Phát huy ý thức tham gia hoạt động nhóm, thảo luận trao đổi kinh nghiệm tìm phương pháp học tập tích cực chủ động Nội dung bài: 2.1 Vocabulary Thời gian: 2.1.1 Some popular circuit breakers and their construction 2.1.2 Practice the conversation 2.2 Grammar Thời gian: 2.2.1 The comparative degree with the comparative of adjective… than 2.2.2 The comparative degree with the comparative of noun …than 2.3 Practice Thời gian: 2.3.1 Practice reading the text about some concepts of engineering 2.3.2 Practice translating the text about some concepts of engineering 2.3.3 Doing the exercises Unit 6: Refrigerators Thời gian: Mục tiêu: Sau học xong này, sinh viên đạt được: - Hiểu sử dụng từ vựng số khái niệm cơng dụng tủ lạnh; - Tóm tắt có hệ thống kiến thức học từ đến 6; - Đọc, dịch giao tiếp cách công dụng tủ lạnh, cách bảo quản thực phẩm tủ lạnh; - Phát huy ý thức tham gia hoạt động nhóm, thảo luận trao đổi kinh nghiệm tìm phương pháp học tập tích cực chủ động Nội dung bài: 2.1 Vocabulary Thời gian: 2.1.1 Usefulness of refrigerators; how to preserve refrigerators 2.1.2 Practice the conversation 2.2 Grammar Thời gian: 2.2.1 The first conditional used to describe things in science and engineering 2.2.2 Using a preposition and noun phrase 2.2.3 Using a relative clause with where 2.3 Practice Thời gian: 2.3.1 Practice reading about two different types of air conditioners; usefulness of refrigerators and how to preserve food 2.3.2 Practice translating the text about two different types of air conditioners; usefulness of refrigerators and how to preserve food 2.3.3 Doing the exercises Achievement test Thời gian: IV Điều kiện thực môn học: Phịng học chun mơn hóa/nhà xưởng: phịng học lý thuyết Trang thiết bị máy móc: máy tính, máy chiếu Projector Học liệu, dụng cụ, nguyên vật liệu: phim, tranh ảnh minh họa tình huống, tài liệu phát tay cho người học, tài liệu tham khảo Các điều kiện khác: không V Nội dung phương pháp, đánh giá: Nội dung: - Kiến thức: Đánh giá thông qua kiểm tra thường xuyên; định kỳ; thi kết thúc môn học, sinh viên cần đạt yêu cầu sau: + Vốn từ vựng kỹ thuật điện khái niệm ngành kỹ thuật, dòng điện, thiết bị điện; + Các điểm văn phạm: Dạng câu bị động, mệnh đề liên hệ, cụm phân từ, câu điều kiện loại một, cách sử dụng giới từ - Kỹ năng: + Dịch thuật tài liệu chuyên ngành thể qua đọc hiểu; + Khả tự học nghiên cứu tài liệu - Năng lực tự chủ trách nhiệm: Đánh giá trình học tập cần đạt yêu cầu sau: + Chấp hành nội qui, qui chế nhà trường; + Chuẩn bị đầy đủ tài liệu hoc tập; + Chuẩn bị đầy đủ nội dung tự học, tự nghiên cứu; + Tham gia đầy đủ thời lượng mơn học, tích cực học Phương pháp: 10 If you put two magnets close together, like poles- for example, two north polesrepel each other, and unlike poles attract each other In a simple electric motor, like the one shown in Fig.2, a piece of iron with loops of wire round it, called an armature, is placed between the north and south poles of a stationary magnet, known as the field magnet When electricity flows around the armature wire, the iron becomes an electromagnet The attraction and repulsion between the poles of this armature magnet and the poles of the field magnet make the armature turn As a result, its north pole is close to the south pole of the field magnet Then the current is reversed so the north pole of the armature magnet becomes the south pole Once again, the attraction and repulsion turning as long as the direction of the current, and therefore its magnetic poles, keeps being reversed Two reverse the direction of the current, the ends of the armature wire are connected to different halves of a split ring called a commutator Current flows to and from the commutator through small carbon blocks called brushes As the armature turns, first one delivering the current, and then the other, so the direction of the current keeps being reversed Match each of these diagram with the correct description, A, 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 direct current (figure 1) 27 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 Describing function 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: The function of an electric motor is to convert electrical energy to mechanical energy Match each of these motor components to its function, and then describe its function in a sentence Component Armature Bearings Brushes Commutator Drive shaft 28 Field windings Function a Transfer rotation from the motor b Create an electromagnetic field c Converts electromagnetic energy to rotations d Reverses the current to the armature e Support the drive shaft f Supply current to the armature D PRACTICE I Now study this description of the motor A simple de motor consist of a 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: Dismantle a piece of equipment into its main parts These expressions will help: Consists of X A A is made up of X and Y is composed of Y Name components: known as Carbon blocks brushes called Locate components: The armature is placed between the poles Connect components: II Complete the text with the help of the diagram on the next page Use the following words: Are make up (cấu thành) 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 29 Word study Study these expressions for describing how components are connected to each other A is bolted to B = A is connected to B with bolts A is welded to B = A is connected to B by welding A is fixed to B = no specific method given III Explain each of these methods of connection Screwed Soldered Attached Wired Bonded Glued Riveted Welded Brazed 10 Nailed 30 Unit 5: Circuit Breakers A DIALOGUE Professor: Have a seat What can I for you? Student: I’m going to be an engineer, but I’m having a little trouble deciding which field to go into The Dean suggested that I have a talk with you about the work of a civil engineer Professor: Well, I don’t know how helpful I can be, but I’ll be glad to give you some general idea of the field Student: Great! That’s just what I want Professor: One of the better known areas is construction engineering It deals with the construction of all kinds of structures, like bridges, factories, dams, and so on Student: Does it include the design? Professor: Not necessarily The structural engineer will usually this His job, of course, is to follow the general design and make sure that the structures are sound He will have to figure stresses and strains, size of beams, etc…It is a very demanding field, because it usually involves a great deal of mathematics Student: I see What about water control, in general? Professor: Oh, yes This is an important field It includes problems in irrigation, flood control, and water supply Another area, not so well known, is sanitary engineering, which deals with sewage and industrial waste Student: Road building must also be an important field Professor: And a very complex one Transportation engineering doesn’t involve only roads, by the way For instance, airport design and construction is a major concern Student: Do civil engineers usually work with a company? Professor: Usually, yes There are large as well as small civil engineering firms Their size depends on the scale of the project they undertake A smaller number of civil engineers become what are known as consultant engineers They are experts in particular fields, and they are consulted by larger firms on specific projects Student: Well, thank you very much Professor: O.K Lots of luck in your career B GRAMMAR The comparative degree: * Form: Verb + comparative adj + than Verb + comparative adj + noun + than 31 Ex: The type of circuit breaker is safer than that one This is a better heat strip than the previous one Since the lower metal strip expands more than the upper piece, the heat strip curves upward C READING 32 (1) The type of circuit protection that is commonly used in homes and in industry is called a circuit breaker (2) It automatically turns off the current when too many amperes flow in the circuit (3) The circuit breaker is a combination of both switch and safety device (4) When the switch is turned to the on position the circuit breaker contacts are closed (5) If a short or overload occurs the breaker open the circuit (6) After the short has been repaired on the load cut down the breaker can be reset by turning the switch to the off position and then back the one position (7) The use of circuit breakers eliminates hunting for a fuse and also prevents a careless person from installing a large fuse that could overload the circuit (8) 33 Circuit breakers are labeled, the same as fuses, with their current carrying capacity (9) There are two types of circuit breaker- the heat strip breaker uses a strip made of two different kinds of metal either welded or riveted together (11) When too much current flows through the strip the metals get hot (12) The heat makes the metals expand but, since they are two different kinds of metals, one expands more than the other (13) Since the lower metal strip expands more than the upper piece, the heat strip curves upward (14) This bending of the heat strip allows a spring in the switch to open the contact points (15) The amount of current necessary to open the contact depends upon the design of the heat strip (16) The magnetic circuit breaker uses an electromagnetic coil to open the circuit (17) A coil is connected in series with the circuit so that all of the current becomes too great the magnetic pull of the coil moves the metal bar called the armature toward the coil (19) As the armature moves toward the coil it breaks the contact points and open the circuit (20) Both the heat strip breaker and the magnetic breaker must be reset by hand before the circuit is closed again I Comprehension check In sentence 2, it means a circuit breaker b type In sentence 7, that means a careless person b large fuse In sentence 12, they means a heat b strip In sentence 17, it means a coil b strip In sentence 19, it means a coil b armature c protection c fuse c metals c current c contact paints II Write the correct statements in your notebook Leave out the incorrect statements The circuit breaker automatically shuts the circuit after a short or overload happens Fuses and circuit breakers are protective devices frequently encountered in power system Circuit breakers are special normally- closed switches which are automatically opened as a result of electrical overload and can be manually reset The circuit breaker has the best combination of switch and safety device 34 When the circuit breaker is being used it should be connected so that it will be in shunt with the device it is to control The magnetic breaker may be adjusted to operate on currents from to amperes or more and it is adjusted by moving the coil toward or away from the contact arm As the coil of breaker is moved away from the contact arm, less current will be needed to operate the breaker The current flow through the heat strip breaker will produce heat which makes the metals melt at low temperature The heat strip will curve upward as long as the lower metal strip expands less than the upper one 10 Each breaker is marked to indicate the amount of current it will handle before it “blows.” 11 Most branch circuits in the home use a 15 ampere breaker type If larger breakers are installed the wire of the circuit can be overloaded and a fire could result from the heat developed in the wire 12 The rating of the breaker is selected according to the number of amperes of current which the wire will carry without melting 13 The main reason why the breaker is manufactured is to move completely placing a large fuse causing the overload found in most homes by careless people 14 The circuit breaker is used where heavy current is needed and on circuits using 220 volts or more 15 The switching operation for the power network is a main function of breaker IV Choose the best answer In sentence 1, commonly means a usually b everywhere c frequently In sentence 2, automatically means a by itself b independently c precisely In sentence 3, combination means a connection b collection c unit In sentence 6, repaired means a overcame b put back in good condition c looked for 5.In sentence 7, eliminates means a reduces b simplifies c removes In sentence 8, labeled means a sealed b printed c marked In sentence 10, strip means a direct contact pattern b join piece c linking couple In sentence 11, get means a become b appear c turn position 35 In sentence 12, expand means a increase in size b enlarge 10 In sentence 14, bending means a changing the size b curving 11 In sentence 19, breaks means a separates by force b interrupts 12 In sentence 20, by hand means a without machinery b manually c develop c moving from customary c cuts off c in skillful manner V Answer the following questions in your own words Name two types of circuit breakers How is a circuit breaker reset after it has opened the circuit? Why is it important to locate the trouble in electrical circuit before replacing a fuse or resetting a circuit breaker? How is a heat strip constructed? Explain how a magnetic circuit breaker operates What is the moving part of a magnetic circuit breaker called? D PRACTICE Translate into Vietnamese A contractor is switch capable of closing and opening the associated circuits up to 1500 times an hour They are used in D.C and A.C circuits operating at up to 1000V They give no short- circuit or overload protection, so they must be used in conjunction with protective devices Contactors are set to operate at 0.85 to 1.03 the rated voltage and will automatically de-energize the associated electric installation if the voltage drops to 0.5 or 0.6 of its rated value An A.C three-pole contactor is designed for currents from 20 to 600 A Its operant time ranges from 0.05 to 0.1s When the “start” button in the control circuit is pressed, the coil of a solenoid, 8, is energized, the core, 7, attracts the armature, 3, and an insulated shaft, 1, rotates in bearings This causes the movable and stationary contacts (2 and 6, respectively) in the power circuit to close, and the motor, 9, is set in motion At the same time, a bridge, 4, rotates to separate the lower interlock contacts, 5, and to close the upper interlock contacts- these interlock contacts lock the contractor in the energized position, and now the “start” button may be released According to the action, the upper interlock contacts are called make (or normally- open, N.O.) contacts, and the lower interlock contacts are called break (or normally-closed, N.C.) contacts When the “stop” button is pressed, the solenoid, 8, is de-energized, and the main contacts are enclosed in arc-chutes In A.C contactors, the magnetic flux in the solenoid, 8, periodically passes through zero value, and this might cause chatter and hum To avoid this, a shading ring (which is a shorted turn) is placed around a portion of the coil core, in which a current is induced as in the secondary winding 36 of a transformer, this current being shifted in phase relative to the current in the solenoid, At the instants when the main flux passes through zero, the flux due to the shading ring prevents the armature to drop out 37 UNIT 6: REFRIGERATORS A DIALOGUE Work in pair Mr.Green: While you’re here, I wish you’d have a look around the house I had a terrible fuel bill last winter My mother-in- law was staying with us and she wanted the temperature around 80 o all the time Engineer: Yes, lots of people overheat their houses Actually 70 o is comfortable, if you let yourself get used to it Mr Green: What’s the most popular heating system used nowadays? Engineer: The warm air system, the kind you have, has become more common because of economy and convenience A heat chamber heats air, which passes through ducts and opening into the rooms by blowers or by convection These openings are called outlets Filters are installed in the ducts to collect dust They can also control humidity to some extent The fuel is usually coal, oil, or gas Mr Green: Are radiators being installed in new house? Engineer: This was the older method, but it’s still in use today It often provides a more even heat, since here the heating is done primarily by radiation However, it does not provide a means of controlling humidity Mr Green: Radiators usually take steam, don’t they? Engineer: Steam or water In the steam system, steam enters the radiator, where it cools off and returns as water to the furnace With the hot water system, the temperature is lower, and hot water is circulated through the radiators and pipes either by gravity or pumps Mr Green: what kind of cooling systems are used in homes? Engineer: Either central or localized air conditioning is used With the central system, air ducts bring cool air into the rooms Sometimes, if the house has warm air heating, the same ducts may be used for air conditioning This system provides an even homes which are not constructed for the central system, small individual air conditioners are installed at several windows This is probably the easiest way, but the temperature of the rooms is quite uneven Mr Green: How important is the insulation of the house? Engineer: Very important, and sometimes this is not appreciated The roof, for example, should have adequate insulation with glass fiber, aluminum foil, or something similar It is important to have vapor seals on the warm side, to avoid moisture when the air cools Double glazing of windows is also very important B GRAMMAR I The first conditional sentence (cont) Action Result If/ when + present tense Present tense Use: They describe things in science and engineering which are always true This action is always followed by the same result Examples: If a liquid is heated, it changes to a gas or vapour If a gas is allowed to expand, it cools down If a gas is compressed, it heats up II Locating a stage in a process Using a preposition + Noun phrase Ex: The liquid turns to vapour in the evaporator The gas cools down in the condenser Using WHERE – Clause, a relative clause with WHERE rather than WHICH or WHO to link a stage, its location, and what happens there Ex: The warm gas passes through the condenser, where it heats the surroundings and cools down The refrigerant circulates around the fridge, where it undergoes changes in pressure and temperature C READING Refrigeration preserves food by lowering its temperature It slows down the growth and reproduction of micro- organisms such as bacteria and the action of enzymes which cause food to rot 39 Refrigeration is based on three principles Firstly, if a liquid is heated, it changes to a gas or vapour When this gas is cooled, it changes back into a liquid Secondly, if a gas is allowed to expand, it cools down If a gas is compressed, it heats up Thirdly, lowing the pressure around a liquid helps it to boil To keep the refrigerator at a constant low temperature, heat must be transferred from the inside of the cabinet to the outside A refrigerant is used to this It is circulated around the fridge, where it undergoes changes in pressure and temperature and changes from a liquid to a gas and back again One common refrigerant is as compound of carbon, chlorine, and fluorine known as R12 This has a very low boiling point: -29 oC At normal room temperature (about 20 oC) the liquid quickly turns into gas However, newer refrigerants which are less harmful to the environment, such as KLEA , are gradually replacing R12 The refrigeration process begins in the compressor This compresses the gas so that it heats up It then pumps the gas into a condenser, a long tube in the shape of a zigzag As the warm gas passes through the condenser, it heats the surroundings and cools down By the time it leaves the condenser, it has condensed back into a liquid Liquid leaving the condenser has to flow down a very narrow tube (a capillary tube) This prevents liquid from leaving the condenser too quickly, and keeps it at a high pressure As the liquid passes from the narrow capillary tube to the larger tubes of the evaporator, the pressure quickly drops The liquid turns to vapour, which expands and cools The cold vapour absorbs heat from the fridge It is then sucked back into the compressor and the process begins again The compressor is switched on and off by the thermostat, a device that regulates temperature, so that the food is not over- frozen I Answer the following questions How does refrigeration preserve food? How many principles is refrigeration based on? What are they? How you think to keep the refrigerator at a constant low temperature? How is the compressor switched not to over - freeze food? II Word forms Each of the verbs in column A has a related noun ending in –er or –or in column B Complete the blanks Verbs Nouns Refrigerate _ Condense _ _ evaporator Compress _ Resist _ _ charger generate _ Conduct _ _ exchanger Radiate _ 40 Control _ III Put these stages in the refrigeration process in the correct sequence a The liquid enters the evaporator b The gas condenses back into a liquid c The vapour is sucked back into the compressor d The gas is compressed e The liquid turns into a vapour f The gas passes through the condenser g The liquid passes through a capillary tube h The high pressure is maintained D PRACTICE I Link each action in column A with a result from column B to describe an important engineering principle Action Result 1.a liquid is heated a.it heats up 2.a gas is cooled b.there is an equal and opposite reaction 3.a gas expands c.It changes to a gas 4.a gas is compressed d.it extends in proportion to the force 5.a force is applied to a body e it is transmitted equally throughout 6.a current passes through a wire the fluid a wire cuts a magnetic field f a current is induced in the wire pressure is applied to the surface of g.it cools down an enclosed fluid h.it sets up a magnetic field around the 9.a force is applied to a spring fixed at wire one end i it changes to a liquid II Complete each of these sentences The gas passes through the compressor, where _ It passes through the condenser, where _ The liquid passes through a capillary tube, where _ The liquid enters the evaporator, where _ The cold vapour is sucked back into the compressor, where Tài liệu tham khảo: [1] Oxford English for Electrical and Mechanical Engineering, Eric H Glendinning & Norman Glendinning, C.Eng, MIMech E, Oxford University Press [2] English Grammar in use, Oxford University Press, second Edition [3] Từ điển Anh - Việt, Việt - Anh, Bamboo Dictionary 41 ... thường sử dụng kỹ thuật Về kỹ năng: - Hình thành phát triển khả giao tiếp, đọc hiểu dịch thuật tài liệu chuyên ngành điện với việc sử dụng từ điển; - Tự tìm kiếm, tự học nghiên cứu tài liệu Về lực...2 TUYÊN BỐ BẢN QUYỀN Tài liệu thuộc loại tài liệu giảng dạy nội sử dụng nhà trường với mục đích làm tài liệu giảng dạy cho giảng viên sinh viên nên nguồn thông tin tham... học này, sinh viên đạt được: Về kiến thức: - Hiểu sử dụng từ vựng chuyên ngành điện: khái niệm ngành kỹ thuật, định nghĩa dòng điện, thiết bị điện bản; - Trình bày động từ đơn, tiếp diễn, hoàn thành,