Table of Contents
Passage
A Refrigerators are the epitome of clunky technology: solid, reliable and just a little bit dull. They have riot changed much over the past century, but then they have not needed to. They are based on a robust and effective idea— draw heat from the thing you want to cool by evaporating a liquid next to it, and then dump that heat by pumping the vapour elsewhere and condensing it. This method of pumping heat from one place to another served mankind well when refrigerators’ main jobs were preserving food and, as air conditioners, cooling buildings. Today’s high-tech world, however, demands high-tech refrigeration. Heat pumps are no longer up to the job. The search is on for something to replace them.
B One set of candidates are known as paraelectric materials. These act like batteries when they undergo a temperature change: attach electrodes to them and they generate a current. This effect is used in infra-red cameras. An array of tiny pieces of paraelectric material can sense the heat radiated by, for example, a person, and the pattern of the array’s electrical outputs can then be used to construct an image. But until recently no one had bothered much with the inverse of this process. That inverse exists, however. Apply an appropriate current to a paraelectric material and it will cool down.
C Someone who is looking at this inverse effect is Alex Mischenko, of Cambridge University. Using commercially available paraelectric film, he and his colleagues have generated temperature drops five times bigger than any previously recorded. That may be enough to change the phenomenon from a laboratory curiosity to something with commercial applications.
D As to what those applications might be, Dr Mischenko is still a little hazy. He has, nevertheless, set up a company to pursue them. He foresees putting his discovery to use in more efficient domestic fridges and air conditioners. The real money, though, may be in cooling computers.
E Gadgets containing microprocessors have been getting hotter for a long time. One consequence of Moore’s Law, which describes the doubling of the number of transistors on a chip every 18 months, is that the amount of heat produced doubles as well. In fact, it more than doubles, because besides increasing in number, the components are getting faster. Heat is released every time a logical operation is performed inside a microprocessor, so the faster the processor is, the more heat it generates. Doubling the frequency quadruples the heat output. And the frequency has doubled a lot. The first Pentium chips sold by Dr Moore’s company, Intel, in 1993, ran at 60m cycles a second. The Pentium 4—the last “single-core” desktop processor—clocked up 3.2 billion cycles a second.
F Disposing of this heat is a big obstruction to further miniaturisation and higher speeds. The innards of a desktop computer commonly hit 80 ℃ . At 85℃, they stop working. Tweaking the processor’s heat sinks (copper or aluminium boxes designed to radiate heat away) has reached its limit. So has tweaking the fans that circulate air over those heat sinks. And the idea of shifting from single-core processors to systems that divided processing power between first two, and then four, subunits, in order to spread the thermal load, also seems to have the end of the road in sight.
G One way out of this may be a second curious physical phenomenon, the thermoelectric effect. Like paraelectric materials, this generates electricity from a heat source and produces cooling from an electrical source. Unlike paraelectrics, a significant body of researchers is already working on it.
H The trick to a good thermoelectric material is a crystal structure in which electrons can flow freely, but the path of phonons—heat-carrying vibrations that are larger than electrons—is constantly interrupted. In practice, this trick is hard to pull off, and thermoelectric materials are thus less efficient than paraelectric ones (or, at least, than those examined by Dr Mischenko). Nevertheless, Rama Venkatasubramanian, of Nextreme Thermal Solutions in North Carolina, claims to have made thermoelectric refrigerators that can sit on the back of computer chips and cool hotspots by 10℃ . Ali Shakouri, of the University of California, Santa Cruz, says his are even smaller—so small that they can go inside the chip.
I The last word in computer cooling, though, may go to a system even less techy than a heat pump—a miniature version of a car radiator. Last year Apple launched a personal computer that is cooled by liquid that is pumped through little channels in the processor, and thence to a radiator, where it gives up its heat to the atmosphere. To improve on this, IBM’s research laboratory in Zurich is experimenting with tiny jets that stir the liquid up and thus make sure all of it eventually touches the outside of the channel—the part where the heat exchange takes place. In the future, therefore, a combination of microchannels and either thermoelectrics or paraelectrics might cool computers. The old, as it were, hand in hand with the new.
Questions
Questions 1-5 Complete each of the following statements with company or the scientist name from the box below. Write the appropriate letters A-F in boxes 1-5 on your answer sheet.
A Apple
B IBM
C Intel
D Alex Mischenko
E Ali Shakouri
F Rama Venkatasubramanian
1 and his research group use paraelectric film available from the market to produce cooling.
2 sold microprocessors running at 60m cycles a second in 1993.
3 says that he has made refrigerators which can cool the hotspots of computer chips by 10℃ .
4 claims to have made a refrigerator small enough to be built into a computer chip.
5 attempts to produce better cooling in personal computers by stirring up liquid with tiny jets to make sure maximum heat exchange.
Questions 6-9 Do the following statements agree with the information given in the reading passage? In boxes 6-9 on your answer sheet write
TRUE if the sataement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if there is no information on this
6 Paraelectric materials can generate a current when electrodes are attached to them.
7 Dr. Mischenko has successfully applied his laboratory discovery to manufacturing more efficient refrigerators.
8 Doubling the frequency of logical operations inside a microprocessor doubles the heat output.
9 IBM will achieve better computer cooling by combining microchannels with paraelectrics.
Question 10 Choose an appropriate letter A-D and write it in box 10 on your answer sheet.
Which method of disposing heat in computers may have a bright prospect?
A Tweaking the processor’s Heat sinks.
B Tweaking the fans that circulate air over the processor heat sinks.
C Shifting from single-core processors to systems of subunits.
D None of the above.
Questions 11-14 Complete the notes. Choose one suitable word from the Reading Passage above for each answer. Write your answers in boxes 11-14 on your answer sheet.
Summary
Traditional refrigerators use 11 ………………pumps to drop temperature. At present, scientists are searching for other methods to produce refrigeration, especially in computer microprocessors 12 ……………… materials have been tried to generate temperature drops five times bigger than any previously recorded. 13 ……………… effect has also been adopted by many researchers to cool hotspots in computers. A miniature version of a car 14 ……………… may also be a system to realize ideal computer cooling in the future.
Answers
Below are the answers, key words, synonyms and full explanations for the IELTS Reading passage Refrigerator (Passage 1, Questions 1–14).
Questions 1–5: Matching People/Companies (A–F)
A Apple · B IBM · C Intel · D Alex Mischenko · E Ali Shakouri · F Rama Venkatasubramanian
1. … and his research group use paraelectric film available from the market to produce cooling.
Answer: D (Alex Mischenko)
Key words: commercially available paraelectric film; temperature drops five times bigger
Synonyms: available from the market = “Using commercially available paraelectric film, he and his colleagues have generated temperature drops five times bigger”
Explanation: Paragraph C: Mischenko uses off-the-shelf paraelectric film to cool.
2. … sold microprocessors running at 60m cycles a second in 1993.
Answer: C (Intel)
Key words: The first Pentium chips sold by … Intel, in 1993, ran at 60m cycles a second
Synonyms: = “The first Pentium chips sold by Dr Moore’s company, Intel, in 1993, ran at 60m cycles a second”
Explanation: Paragraph E: Intel sold the 60 MHz Pentium in 1993.
3. … says he has made refrigerators which can cool the hotspots of computer chips by 10 ℃.
Answer: F (Rama Venkatasubramanian)
Key words: thermoelectric refrigerators that can sit on the back of computer chips and cool hotspots by 10 ℃
Synonyms: = “Rama Venkatasubramanian … claims to have made thermoelectric refrigerators that can … cool hotspots by 10 ℃”
Explanation: Paragraph H: Venkatasubramanian’s device cools chip hotspots by 10 ℃.
4. … claims to have made a refrigerator small enough to be built into a computer chip.
Answer: E (Ali Shakouri)
Key words: his are even smaller—so small that they can go inside the chip
Synonyms: built into a chip = “Ali Shakouri … says his are even smaller—so small that they can go inside the chip”
Explanation: Paragraph H: Shakouri’s coolers fit inside the chip.
5. … tries to produce better cooling in PCs by stirring up liquid with tiny jets for maximum heat exchange.
Answer: B (IBM)
Key words: tiny jets that stir the liquid up … the part where the heat exchange takes place
Synonyms: = “IBM’s research laboratory in Zurich is experimenting with tiny jets that stir the liquid up and thus make sure all of it … touches the outside of the channel”
Explanation: Paragraph I: IBM uses tiny jets to stir the cooling liquid.
Questions 6–9: True / False / Not Given
6. Paraelectric materials can generate a current when electrodes are attached to them.
Answer: TRUE
Key words: attach electrodes to them and they generate a current
Synonyms: = “These act like batteries when they undergo a temperature change: attach electrodes to them and they generate a current”
Explanation: Paragraph B confirms this directly → TRUE.
7. Dr Mischenko has successfully applied his laboratory discovery to manufacturing more efficient refrigerators.
Answer: FALSE
Key words: still a little hazy; He foresees putting his discovery to use
Synonyms: only foresees, not yet done = “Dr Mischenko is still a little hazy … He foresees putting his discovery to use in more efficient domestic fridges”
Explanation: Paragraph D: he only foresees/plans applications and has set up a company — he has not yet manufactured anything → FALSE.
8. Doubling the frequency of logical operations inside a microprocessor doubles the heat output.
Answer: FALSE
Key words: Doubling the frequency quadruples the heat output
Synonyms: quadruples, not doubles = “Doubling the frequency quadruples the heat output”
Explanation: Paragraph E says the heat quadruples, so the statement is false.
9. IBM will achieve better computer cooling by combining microchannels with paraelectrics.
Answer: NOT GIVEN
Key words: a combination of microchannels and either thermoelectrics or paraelectrics might cool computers
Synonyms: The passage only makes a general prediction — “a combination of microchannels and either thermoelectrics or paraelectrics might cool computers” — it does not say IBM specifically will use paraelectrics.
Explanation: Paragraph I: IBM’s own work is on microchannels/jets; pairing IBM with paraelectrics is not stated → NOT GIVEN.
Question 10: Multiple Choice
10. Which method of disposing of heat in computers may have a bright prospect?
Answer: D (None of the above)
Key words: tweaking … heat sinks … has reached its limit; so has tweaking the fans; the end of the road in sight
Synonyms: all exhausted = “Tweaking the processor’s heat sinks … has reached its limit. So has tweaking the fans … the idea of shifting … also seems to have the end of the road in sight”
Explanation: Paragraph F says heat sinks (A), fans (B) and multi-core (C) are all exhausted, so the promising method is none of these → D.
Questions 11–14: Notes Completion (ONE WORD ONLY)
11. Traditional refrigerators use ……… pumps to drop temperature.
Answer: heat
Key words: pumping heat from one place to another; Heat pumps
Synonyms: = “This method of pumping heat from one place to another … Heat pumps are no longer up to the job”
Explanation: Paragraphs A: traditional fridges are heat pumps.
12. ……… materials generate temperature drops five times bigger than any previously recorded.
Answer: paraelectric
Key words: paraelectric film … temperature drops five times bigger
Synonyms: = “Using commercially available paraelectric film … temperature drops five times bigger than any previously recorded”
Explanation: Paragraph C: paraelectric materials give the five-times-bigger drop.
13. The ……… effect has also been adopted by many researchers to cool hotspots in computers.
Answer: thermoelectric
Key words: the thermoelectric effect; a significant body of researchers is already working on it
Synonyms: = “a second curious physical phenomenon, the thermoelectric effect … a significant body of researchers is already working on it”
Explanation: Paragraphs G–H: the thermoelectric effect is widely researched for chip cooling.
14. A miniature version of a car ……… may also be a future computer-cooling system.
Answer: radiator
Key words: a miniature version of a car radiator
Synonyms: = “a system even less techy than a heat pump—a miniature version of a car radiator”
Explanation: Paragraph I: the idea is a tiny car radiator.
Answer Key (Quick Reference)
| Q | Answer | Q | Answer |
|---|---|---|---|
| 1 | D (Mischenko) | 8 | FALSE |
| 2 | C (Intel) | 9 | NOT GIVEN |
| 3 | F (Venkatasubramanian) | 10 | D |
| 4 | E (Shakouri) | 11 | heat |
| 5 | B (IBM) | 12 | paraelectric |
| 6 | TRUE | 13 | thermoelectric |
| 7 | FALSE | 14 | radiator |
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