The vapor pressure of a gas is the pressure necessary to keep it in a(n)______.A.Soluble stateB.Solid stateC.Liquefied stateD.Inert state
The vapor pressure of a gas is the pressure necessary to keep it in a(n)______.
A.Soluble state
B.Solid state
C.Liquefied state
D.Inert state
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The maximum pressure developed by a waste heat boiler is determined by the main engine exhaust ______.A.gas compositionB.gas temperatureC.pressureD.timing
How does an inert gas system on a tanker function to prevent explosions in cargo tanks?A.De-energizes the "charged mist" effectB.Maintains a positive pressure on the vent header to cool the flammable vaporsC.Inert gas filters out the flammable vapors from the cargo tank spacesD.Inert gas dilutes the flammable vapor and air concentrations to keep them below the lower explosive limit
Which method is used to supply inert gas from a flue gas system to the cargo tanks?A.Exhaust gas pressure from the stackB.High capacity fanC.Inert gas compressorD.Natural aspiration
You are discharging cargo and the inert gas system is in operation to inert the tanks. The pressure in a tank being discharged starts to drop below the allowable limit. What action should you take?A.Cut in another IG fan to increase gas flowB.Open the pressure control valve until the pressure increasesC.Open the tank isolation valve to the fully open positionD.Reduce the pumping rate
Reid vapor pressure is ______.A.exerted by liquid cargo on the sides of a tankB.exerted by liquid cargo on a cargo hose bodyC.the lowest temperature and pressure that will cause a flammable liquid to give off vaporsD.a measurement of the amount of flammable vapors given off by a liquid at a certain temperature
What best describes for how long a gas-free test is good ________.A.For as long as is indicated on the gas-free certificateB.For the instant that it is madeC.Until valves in line with the tank or compartment are reopenedD.Until changes in temperature or pressure affect the vapor content in the space
A microbarograph is a precision instrument that provides a ______.A.charted record of atmospheric temperature over timeB.charted record of atmospheric pressure over timeC.graphic record of combustible gases measured in an atmosphereD.graphic record of vapor pressure from a flammable/combustible liquid
A heated bulkhead has the effect on a hygroscopic commodity of ______.A.causing moisture to accumulate against the bulkheadB.lowering the vapor pressure of the commodityC.lowering the dew point of the airD.raising the vapor pressure of the commodity
单选题How does an inert gas system on a tanker function to prevent explosions in cargo tanks? ()ADe-energizes the charged mist effectBMaintains a positive pressure on the vent header to cool the flammable vaporsCInert gas filters out the flammable vapors from the cargo tank spacesDInert gas dilutes the flammable vapor and air concentrations to keep them below the lower explosive limit
单选题During loading and discharging operations,in addition to when the cargo tanks have been properly filled,each inert gas system must be capable of maintaining a minimum gas pressure of().A150 millimeters of water pressureB125 millimeters of water pressureC100 millimeters of water pressureD75 millimeters of water pressure
单选题The vapor pressure of a substance().Adecreases as temperature increasesBincreases with the temperatureCis not affected by temperatureDmay increase or decrease as the temperature rises
单选题The vapor pressure of a gas is the pressure necessary to keep it in a(n)().Asoluble stateBsolid stateCliquefied stateDinert state
单选题If a large difference exists between the compressor discharge pressure and the pressure corresponding to the existing condensing temperature in a refrigeration system, you should().Aincrease the flow of the cooling water through the condenserBadjust the high pressure cutout to maintain the desired pressureCopen the hot gas bypass temporarily to reduce capacityDpurge non-condensable gases to reduce the excess pressure
单选题A flash-type evaporator discharges heated seawater into a chamber that is maintained at a pressure than the vapor pressure of the entering heated seawater, and subsequently the flashed water vapor thereby produced()Alower condensingBhigher coolingClower coolingDhigher condensing
单选题A heated bulkhead has the effect on a hygroscopic commodity of().Acausing moisture to accumulate against the bulkheadBlowering the vapor pressure of the commodityClowering the dew point of the airDraising the vapor pressure of the commodity
单选题Diesel engine exhaust noise can be reduced in an exhaust muffler by ()Achanging the direction of exhaust gas flowBincreasing the exhaust gas velocityCchanging the exhaust gas weightDincreasing the exhaust gas static pressure
问答题The difference between a liquid and a gas is obvious (1)____ the conditions of temperature and pressure commonly found at the surface of the Earth. A liquid can be kept in an open container and fills it to the level of a free surface. A gas forms no free surface but tends to diffuse throughout the space available; it must (2)____ be kept in a closed container, as in the (3)____ of a planet’s atmosphere. The distinction was a prominent feature of early theories (4)____(describe) the phases of matter. In the nineteenth century, for example, one theory maintained that a liquid could be “dissolved” in a vapor without losing its identity, and another theory held that the two phases are made up of different kinds of molecules (分子). The theories now prevailing (5) t____ a quite different approach by emphasizing what liquids and gases have in common. They are both forms of matter (6)____ have no permanent structure, and they both flow easily. They are fluids.The (7)____(fundament) similarity of liquids and gases becomes clearly apparent when the temperature and pressure are raised somewhat. Suppose a closed container partially filled with a liquid is heated. The liquid expands, or in other (8)____, becomes less dense; some of it evaporates. In contrast, the vapor above the liquid surface becomes dense as the evaporated molecules are added to it. The combination of temperature and pressure (9)____ which the densities become equal is called the critical point. Above the critical point the liquid and the gas can no longer be (10)____(distinguish); there is a single, undifferentiated fluid phase of uniform density.
单选题A microbarograph is a precision instrument that provides a().Acharted record of atmospheric temperature over timeBcharted record of atmospheric pressure over timeCgraphic record of combustible gases measured in an atmosphereDgraphic record of vapor pressure from a flammable/combustible liquid
单选题During the fuel injection period, fuel pressure must exceed cylinder gas pressure to ().Aensure penetration and distribution of the fuel in the combustion chamberBensure the needle valve is flushed clean during each injectionCprevent combustion gas blowback into the open needle valveDprevent reflected pressure waves when the needle valve closes
单选题A liquid indicator sight glass is useful in determining whether or not a refrigeration system is sufficiently chargedIt is generally located in the().Ahigh pressure liquid lineBlow pressure liquid lineChigh pressure vapor lineDlow pressure vapor line
单选题A(n) () is a device which adds to the energy of a liquid or gas causing an increase in its pressure and a movement of the fluid.ApumpBengineCturbineDboiler
单选题The direction of the surface wind is().Adirectly from high pressure toward low pressureBdirectly from low pressure toward high pressureCfrom high pressure toward low pressure deflected by the earth's rotationDfrom low pressure toward high pressure deflected by the earth's rotation
单选题The expansion valve on a Freon system controls the ().Asuperheat of the gas leaving the compressorBback pressure in the evaporatorCtemperature of the iceboxDsuperheat of the gas leaving the evaporator
单选题You are discharging cargo and the inert gas system is in operation to inert the tanks. The pressure in a tank being discharged starts to drop below the allowable limit. What action should you take? ()ACut in another IG fan to increase gas flowBOpen the pressure control valve until the pressure increasesCOpen the tank isolation valve to the fully open positionDReduce the pumping rate
单选题The refrigerant leaves the evaporator of a refrigeration system as a low pressure ().Asub-cooled liquidBhigh temperature liquidCoil saturated liquidDsuperheated vapor
单选题What is the substance called which can readily be converted from a liquid into a vapor, and also from a vapor into liquid with a reasonably narrow range of pressure?()ARefrigeratorBRefrigerantCCooling mediumDBrine
单选题Which method is used to supply inert gas from a flue gas system to the cargo tanks?()AExhaust gas pressure from the stackBHigh capacity fanCInert gas compressorDNatural aspiration