单选题Since heat will not flow freely from a body at a （） temperature to another at a （） temperature, it is necessary to expend mechanical work, heat, or electrical energy from an external source to achieve refrigeration.Alower；higherBshallower；deeperClarger；smallerDhigher；lower
单选题
Since heat will not flow freely from a body at a （） temperature to another at a （） temperature, it is necessary to expend mechanical work, heat, or electrical energy from an external source to achieve refrigeration.
A
lower；higher
B
shallower；deeper
C
larger；smaller
D
higher；lower
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Which of the following statements about the warm-blooded mammals is true according to the text?A. They can change their environments.B. They can adjust body heat to keep their ideal temperature.C. They can make food from chemicals.D. They get most of their heat from the environment.
第二组The only attention that heat exchanger should require is to ensure that the heat transfer surfaces remain substantially clean and the flow passages generally clear of obstruction. Indication that undue fouling is occurring is given by a progressive increase in the temperature difference between the two fluids, over a period of time, usually accompanied by a noticeable rise in pressure loss at a given flow.Fouling on the sea-water side is the most usual cause of deterioration in performance. The method of cleaning the sea water-side surfaces depends on the type of heat exchanger. With shell-and-tube heat exchangers, the removal of the header covers or, m the case of the smaller heat exchangers, the headers themselves, will provide access to the tubes. Obstructions, dirt, scale etc., can then be removed, using the tools provided by the heat exchanger manufacturer. Flushing through with fresh water is recommended before a heat exchanger is returned to service. In some applications, such as piston oil cooling, progressive fouling may take place on the outside of the tubes. Most manufactures recommend a chemical flushing pr6cess to remove this in situ~ without dismantling the heat exchanger.Plate heat exchangers may be cleaned by unclamping the stack of plates and mechanically cleaning the surface of each plate as recommended by the manufacturers. The plate seals may require replacement from time to time and here the manufacturers instructions should be closely followedBy which of the following indication, can we conclude that the lube oil-sea water heat exchanger is unduly fouled?A.the heat exchanger lube oil inlet temperature loweringB.the heat exchanger sea-water outlet pressure riseC.the heat exchanger temperature difference between lube oil and sea water increasingD.the heat exchanger pressure difference between sea water inlet and outlet decreasing
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Heat exhaustion is caused by excessive ______.A.loss of body temperatureB.loss of water and salt from the bodyC.gain in body temperatureD.intake of water when working or exercising
共用题干第一篇Heat and HealthExtremely hot weather is common in many parts of the world.Although hot weather just makes most people hot,it can cause medical problems and death.Health experts say that since the year 1900,extremely hot weather has killed more people in the United States than any other natural event.One year一the unusually hot summer of 1980一heat caused about 1,700 deaths in the United States.In 1995,more than 600 people died in a similar heat wave in one city一Chicago.To measure extreme heat,government weather experts have developed the Mean Heat Index.It measures the average of how hot it is felt all day on an extremely hot day.Experts say it is the total heat of a hot day or several hot days that can affect health.Several hot days are considered a heat wave.Experts say heat waves often become deadly when the nighttime temperature does not drop much from the highest daytime temperature.The most common medical problem caused by hot weather is heat stress.It is also least severe.For most people,the only result of heat stress is muscle pain.The pain is a warning that the body is becoming too hot. Doctors say drinking water will help the pain disappear after the body again has the right amounts of water and salt.For some people, however,the result is much more serious.For example,doctors say some people face a greatly increased danger from heat stress.These people have a weak or damaged heart,high blood pressure,or other problems of the blood system.Severe heat can help cause a heart attack or stroke.Health experts say this is the most common cause of death linked to hot weather. A heat wave is a period of time during whichA:the weather is much better than usual.B:the nights are much longer than usual.C:the weather is much hotter than usual.D:the days are much longer than usual.
共用题干第一篇Heat and HealthExtremely hot weather is common in many parts of the world.Although hot weather just makes most people hot,it can cause medical problems and death.Health experts say that since the year 1900,extremely hot weather has killed more people in the United States than any other natural event.One year一the unusually hot summer of 1980一heat caused about 1,700 deaths in the United States.In 1995,more than 600 people died in a similar heat wave in one city一Chicago.To measure extreme heat,government weather experts have developed the Mean Heat Index.It measures the average of how hot it is felt all day on an extremely hot day.Experts say it is the total heat of a hot day or several hot days that can affect health.Several hot days are considered a heat wave.Experts say heat waves often become deadly when the nighttime temperature does not drop much from the highest daytime temperature.The most common medical problem caused by hot weather is heat stress.It is also least severe.For most people,the only result of heat stress is muscle pain.The pain is a warning that the body is becoming too hot. Doctors say drinking water will help the pain disappear after the body again has the right amounts of water and salt.For some people, however,the result is much more serious.For example,doctors say some people face a greatly increased danger from heat stress.These people have a weak or damaged heart,high blood pressure,or other problems of the blood system.Severe heat can help cause a heart attack or stroke.Health experts say this is the most common cause of death linked to hot weather. What can people learn from the Mean Heat Index?A:The average temperature of an extremely hot day.B:The highest temperature of an extremely hot day.C:The lowest temperature of an extremely hot day.D:The nighttime temperature of an extremely hot day.
共用题干第一篇Heat and HealthExtremely hot weather is common in many parts of the world.Although hot weather just makes most people hot,it can cause medical problems and death.Health experts say that since the year 1900,extremely hot weather has killed more people in the United States than any other natural event.One year一the unusually hot summer of 1980一heat caused about 1,700 deaths in the United States.In 1995,more than 600 people died in a similar heat wave in one city一Chicago.To measure extreme heat,government weather experts have developed the Mean Heat Index.It measures the average of how hot it is felt all day on an extremely hot day.Experts say it is the total heat of a hot day or several hot days that can affect health.Several hot days are considered a heat wave.Experts say heat waves often become deadly when the nighttime temperature does not drop much from the highest daytime temperature.The most common medical problem caused by hot weather is heat stress.It is also least severe.For most people,the only result of heat stress is muscle pain.The pain is a warning that the body is becoming too hot. Doctors say drinking water will help the pain disappear after the body again has the right amounts of water and salt.For some people, however,the result is much more serious.For example,doctors say some people face a greatly increased danger from heat stress.These people have a weak or damaged heart,high blood pressure,or other problems of the blood system.Severe heat can help cause a heart attack or stroke.Health experts say this is the most common cause of death linked to hot weather. Muscle pain in hot weather means that your body needsA:more exercise. B:more water.C:less oxygen. D:less sugar.
共用题干第一篇Heat and HealthExtremely hot weather is common in many parts of the world.Although hot weather just makes most people hot,it can cause medical problems and death.Health experts say that since the year 1900,extremely hot weather has killed more people in the United States than any other natural event.One year一the unusually hot summer of 1980一heat caused about 1,700 deaths in the United States.In 1995,more than 600 people died in a similar heat wave in one city一Chicago.To measure extreme heat,government weather experts have developed the Mean Heat Index.It measures the average of how hot it is felt all day on an extremely hot day.Experts say it is the total heat of a hot day or several hot days that can affect health.Several hot days are considered a heat wave.Experts say heat waves often become deadly when the nighttime temperature does not drop much from the highest daytime temperature.The most common medical problem caused by hot weather is heat stress.It is also least severe.For most people,the only result of heat stress is muscle pain.The pain is a warning that the body is becoming too hot. Doctors say drinking water will help the pain disappear after the body again has the right amounts of water and salt.For some people, however,the result is much more serious.For example,doctors say some people face a greatly increased danger from heat stress.These people have a weak or damaged heart,high blood pressure,or other problems of the blood system.Severe heat can help cause a heart attack or stroke.Health experts say this is the most common cause of death linked to hot weather. How many people died from heat in Chicago in 1995?A: About 1700. B: Nearly 1900.C: Around 1100. D: Over 600.
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共用题干Heat Is Killer Extremely hot weather is common in many parts of the world.Although hot weather just makes most people feel hot,it can_______(51)serious medical problems-even death.Floods,storms,volcano eruptions and other natural______(52)kill thousands of people every year.So______(53) extreme heat.Experts say heat may be nature's deadliest killer, Recently,extreme heat was blamed ______(54)killing more than one hundred people in India.It is reported that the total heat of a hot day or several days can______(55)health.Several hot days are considered a heat wave.Experts say heat waves often become dangerous when the nighttime temperature does not_______(56)much from the highest daytime temperature.This causes great stress on the human body. Doctors say people can do many things to______(57)themselves from the dangers of extreme heat. Stay out of the sun,if possible.Drink lots of cool water.Wear light colored clothing made______(58) natural materials;avoid wearing synthetic clothing.Make sure the clothing is______(59),permitting freedom of movement.And learn the danger______(60)of the medical problems,such as headache and vomiting,that are linked to heat.Most people suffer only muscle pain as a(n)______(61)of heat stress.The fiain is a______(62)that the body is becoming too hot.Doctors say those suffering headache or muscle pain should stop all activity,rest in a cool place and drink cool liquids.Do not return to physical _______(63)for a few hours because more serious conditions could develop. Doctors say some people face an______(64)danger from heat stress.Such persons have a weak or damaged heart,high blood pressure,or other problems of the blood system. Hot Weather also increases dangers for people who must take______(65)for high blood pressure, poor blood flow,nervousness or depression.58._________A:from B:in C:for D:of
共用题干How the Body Keeps the Same TemperatureThe temperature of your body should always be the same if you are fine,no matter whether the weather is hot or cold.That is why the doctor tests your temperature with a thermometer when you are sick.Normally, your body teniperature is ninety-eight point six degrees Fahrenheit.If it is_______(51)than that,it is a stire sign that something is wrong with your body.Your body keeps the same temperature all the time,because it balances the heat it produces and theheat it_______(52)off. It is always burning up food and producing heat.It can produce heat faster when the body needs or give off heat faster when the body becomes too warm.Let's see_______(53) this works.The heat of your body is given off chiefly through the skin.When you feel_______(54),your skin is tight and shows"goose flesh".When you feel chilly,you must_______(55)around to keep warm._______(56)your muscles begin to work,bum up fuel and produce more heat.It is not_______(57)toshiver,so you usually prefer warming up by taking exercise,or put_______(58)more clothes to keep warm。When you get warm,the skin is loose and soft. It is so supplied_______(59)blood that heat is giv-en off rapidly. If you get too warm,you begin to sweat and_______(60)body heat is used in evaporating the, moisture in your body.In warm_______(61)or warm rooms,you wear less clothing,_______ (62)heat can be given off freely. You prefer less exercise because your body is warm_______(63),and the extra heat produced by taking too much exercise makes you uncomfortable.Now you see why you_______(64)differently in different kinds of weather. In summer,when it is hot,you feel tired and lazy.You do not care to work or play,but enjoy lying down and doing nothing. When you get out of door in winter,the cold air makes you feel_______(65).You want to run and play._________(61)A:weatherB:climateC:circumstanceD:environment
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Which of the following channels air flow through a server chassis？（）A、FansB、DuctsC、Heat sinksD、Condensers
Which of the following components channels air flow through a server chassis？（）A、 FanB、 Heat sinkC、 ShroudD、 Radiator
When comparing capacity-to-capacity， the IBM Rear Door Heat eXchanger helps provide more advantages than other available thermal environment solutions， usually at a fraction of the cost. Which of the following statements is NOT an advantage of the IBM Rear Door Heat eXchanger？ （）A、The IBM Rear Door Heat eXchanger may dramatically unburden existing AC units by cooling the air before it exhausts from the electronics into the hot aisle.B、The IBM Rear Door Heat eXchanger is a "hang， plug， and run" design so the units may be added quickly.C、The IBM Rear Door Heat eXchanger is equipped with two fans to help maintain water temperature at 18C （64.4F） and provide even air flow.D、The IBM Rear Door Heat eXchanger is designed to support a 42U rack.
单选题The heat removed from the refrigerant in the condenser of a refrigeration plant is the （）Alatent heat of expansionBsensible heat of condensationCheat of compressionDall of the above
单选题Since heat will not flow freely from a body at a （） temperature to another at a （） temperature, it is necessary to expend mechanical work, heat, or electrical energy from an external source to achieve refrigeration.Alower；higherBshallower；deeperClarger；smallerDhigher；lower
问答题Practice 1 Extremely hot weather is common in many parts of the world. Although hot weather just makes most people feel hot, it can cause serious medical problems even death. Floods, storms, volcano eruptions and other natural disasters kill thousands of people every year. (1)______ Experts say heat may be nature’s deadliest killer. Recently, extreme heat was Named for killing more than one hundred people in India It is reported that the total heat of a hot day or several days can affect health. (2) ______ Experts say heat waves often become dangerous when the nighttime temperature does not drop much from the highest daytime temperature. This causes great stress on the human body. (3) ______ Stay out of the sun, if possible. Drink lots of cool water: Wear light colored clothing made of natural materials; avoid wearing synthetic clothing. Make sure the clothing is loose, permitting freedom of movement. And learn the danger signs of the medical problems, such as headache and vomiting, that are linked to heat. (4) ______ The pain is a warning that the body is becoming too hot. Doctors say those suffering headache or muscle pain should stop all activity and rest in a cool place and drink cool liquids. Do not return to physical activity for a few hours because more serious conditions could develop. Doctors say some people face an increased danger from heat stress. (5) ______ Hot weather also increases dangers for people who must take medicine for high blood pressure, poor blood flow, nervousness or depression.[A] Such persons have a weak or damaged heart, high blood pressure, or other problems of the blood system.[B] Several of these conditions are present at the same time.[C] Most people suffer only muscle pain as a result of heat stress.[D] Several hot days are considered a heat wave.[E] So does extreme heat.[F] Doctors say people can do many things to protect themselves from the dangers of extreme heat.[G] Heat can be both beneficial and dangerous.
问答题Practice 1 Heat loss by sweating depends on the fact that when a liquid evaporates, it absorbs an enormous quantity of heat from its surroundings. Therefore, when I am of sweat evaporate, a great deal of heat is absorbed from the surface of the body in contact with it. 1______ 2______ The first is the amount of movement of air surrounding the body. The second is the amount of water vapor in the air that surrounds the body. 3______ For this reason, sweat evaporates very rapidly on windy days, and the rate of heat loss by sweating is much more than on a still day. This accounts for the fact that hot still days are much less comfortable than hot windy days. In contrast, the sweat evaporates very rapidly on hot windy days, and cools the body quickly and effectively. 4______ When air is carrying the maximum amount of water vapor that it can hold, it is said to be 100% saturated with water vapor. The relative humidity of the air is said to be 100%. Under these conditions the air cannot carry any water, so no water can evaporate. When the relative humidity is high, therefore, sweat cannot evaporate. Instead, it forms large drops and runs off your skin without cooling you. 5______ It is obvious that under these conditions, evaporation will be much more rapid. Therefore, sweating will be much more effective as a method of losing heat from the body. On a hot dry day, sweat evaporates as soon as it is formed, and you feel reasonably cool even though the temperature of your environment is very high.[A] When the air is very dry and carries no water at all, the relative humidity is said to be 0%.[B] The second factor is the amount of water vapor in the air－the humidity.[C] Hot windy days are much more comfortable than hot still days.[D] This heat transfer occurs even if the environment is hotter than the body.[E] When air moves over the surface of water, the amount of evaporation is greatly increased.[F] You might expect the highest incidence of a heat stroke when the maximum temperature is 100 and humidity is 50%.[G] Two factors affect the rate of evaporation of sweat, and therefore the effectiveness of sweating as a method of cooling the body.
单选题The rate of heat transfer from a hot region to a cold region is affected most by the （）.Asize of the heat sinkBtemperature difference between the regionsCsize of the heat sourceDtotal heat of the system
单选题The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.Aremain constant along the tubes lengthBbe greatest in a single pass counter flow heat exchangerCremain constant throughout the heat exchangerDvary from section to section through out the heat exchanger
单选题The House Speaker and the temporary President of the Senate are usually（）Aelected by the majority partyBchosen from the majority and minority partiesCmembers of the majority partyDchosen freely from the Congressmen and Senators
单选题Symptoms of heat stroke are（）.Acold and moist skin，high body temperatureBcold and dry skin，low body temperatureChot and moist skin，high body temperatureDhot and dry skin，high body temperature
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单选题Physical exertion on the part of a person who has fallen into cold water would（）.Abe the best thing to try if there was no rescue in sightBincrease survival time in the waterCincrease the rate of heat loss from the bodyDnot affect the heat loss from the body
单选题In a shell-and-tube type hydraulic fluid cooler, the amount of heat transferred from the hydraulic fluid to the cooling water depends upon（）Athe temperature of the hydraulic fluidBthe flow rate of the hydraulic fluidCthe temperature of the cooling waterDall of the above