网友您好， 请在下方输入框内输入要搜索的题目：
题目内容
（请给出正确答案）
单选题
One of the main purposes of refractories in a boiler furnace is to（）
A
help preheat the air for the furnaces
B
help preheat the feedwater
C
protect economizer from excessive heat
D
prevent excessive furnace heat losses
参考答案
参考解析
解析：
暂无解析
更多 “单选题One of the main purposes of refractories in a boiler furnace is to（）A help preheat the air for the furnacesB help preheat the feedwaterC protect economizer from excessive heatD prevent excessive furnace heat losses” 相关考题
考题
6 Communication is important for all organisations and requires an understanding of communication flows and channels.Required:(a) Briefly explain the main purposes of the three main formal communication channels in an organisation:(i) Downwards; (3 marks)
考题
According to the passage, the main purposes of futures contracts are ______.A．to hedgeB．to speculateC．to arbitrageD．all of the above
考题
In a()boiler the hot gases from the furnace pass gases from the furnace pass water is on the outside.
A.water-tubeB.fire-tubeC.exhaust gasD.composite
考题
The maximum pressure developed by a waste heat boiler is determined by the main engine exhaust ______.A.gas compositionB.gas temperatureC.pressureD.timing
考题
A fire pump may be used for other purposes if ______.A.the other services are run off a reducing station with a pressure gageB.one of the required pumps is kept available for use on the fire main system at all timesC.no relief valves are installedD.all of the above conditions are met
考题
Texts are usually used in English classes for two main purposes: as a way of developing reading comprehension and as a way of learning new language.（）A对B错
考题
One of the main advantages of a graphite-furnace atomizer is that（）A、It requires only very small quantities of a sampleB、It requires metal.ions in aqueous solutionC、It does not produce background emission like a flameD、It does not get hot like a flame
考题
Texts are usually used in English classes for two main purposes: as a way of developing reading comprehension and as a way of learning new language.（）
考题
The air waybill number is the identification of each consignment and comprises three parts（）.A、the main portion identifying the consignmentB、a three-digit prefix identifying the carrierC、the main portion identifying the carrierD、the last check digit for accounting and security purposes
考题
Which three statements about subqueries are true? （）A、A main query can have more than one subquery.B、A subquery can have more than one main query.C、The subquery and main query must retrieve data from the same table.D、The subquery and main query can retrieve data from different tables.E、Only one column or expression can be compared between the subquery and main query.F、Multiple columns or expression can be compared between the subquery and main query.
考题
You are designing a site topology for the new Active Directory environment. What should you do?（）A、Create one site for all offices. Place the subnets for the four branch offices and the Sydney main office in this site. B、Create two sites: one site for the four branch offices and one site for the Sydney main office. Place the subnets for the branch offices in one site. Place the subnet for the Sydney main office in the other site. C、Create three sites: one site for the four branch offices, one site for the Sydney main office, and one site for the Sydney satellite offices. D、Create four sites: one for the Melbourne and Perth branch offices, one site for the Berlin and Paris branch offices, one site for the Sydney main office, and one site for the Sydney satellite offices. E、Create five sites; one site for the Melbourne branch office, one site for the Perth branch office, one site for the Berlin branch office, one site for the Paris branch office, and one site for the Sydney main office. Place the subnets for each branch office and the Sydney main office in their respective sites.
考题
单选题One of the main advantages of a graphite-furnace atomizer is that（）A
It requires only very small quantities of a sampleB
It requires metal.ions in aqueous solutionC
It does not produce background emission like a flameD
It does not get hot like a flame
考题
单选题Too much air in the furnace of an oil-fired boiler would be indicated by （）.A
yellowish flameB
golden yellow flameC
white flameD
brilliant white flame
考题
单选题In the event of a flame failure in an auxiliary water-tube boiler, you must（）A
relight the boiler immediately to prevent loss of steam pressureB
relight the fire off the brickwork as the bricks are cherry redC
purge the furnace of any combustible gases before attempting to relight the fireD
speed up the feed pump to prevent dry firing when the burner flame is reestablished
考题
单选题A distorted furnace in a fire-tube auxiliary boiler may be the result of （）A
firing for extended periods in the low fire modeB
overheating, due to waterside depositsC
varying the water level above the crown sheetD
carrying excessive alkalinity in the boiler water
考题
单选题（）are supplied by main switchboard directly.A
Suez Canal searchlight, air compressor and air conditioning compressorB
Air compressor, boiler blower and refrigeration plantC
Boiler blower, Suez Canal searchlight and refrigeration plantD
Suez canal searchlight, air compressor and boiler blower
考题
单选题Diesel engine waste heat boiler construction is usually of the fire-tube or（）A
cyclone furnace boiler typeB
dry back boiler typeC
water-tube typeD
critical circulation boiler type
考题
单选题A dazzling white burner flame in the boiler furnace indicates （）.A
proper combustionB
water in the fuelC
excess airD
cold fuel oil
考题
单选题In a （） boiler the hot gases from the furnace pass through the tubes while the water is on the outside.A
water-tubeB
fire-tubeC
exhaust gasD
None of the above is true
考题
单选题The purpose of the programmed purge cycle on an automatically fired auxiliary boiler is to（）A
cool the furnace to prevent pre-ignitionB
remove explosive vapors from the furnaceC
evaporate accumulated unburned fuel oilD
provide sufficient air in the furnace to allow ignition of the fuel
考题
单选题The maximum pressure developed by a waste heat boiler is determined by the main engine exhaust （）.A
gas compositionB
gas temperatureC
pressureD
timing
考题
单选题Multiple fire pumps may be used for other purposes provided that one pump is（）.A
on line to the fire mainB
kept available for use on the fire main at all timesC
capable of being connected to the fire mainD
rated at or above 125 psi
考题
单选题Which one is not the normal operation for boiler shutdown?（）A
Carry out soot blowing if permissibleB
Change fuel supply to diesel oilC
Close steam stop valves on boiler when pressure is reducedD
Drain boiler empty when it has cooled down
考题
多选题The air waybill number is the identification of each consignment and comprises three parts（）.Athe main portion identifying the consignmentBa three-digit prefix identifying the carrierCthe main portion identifying the carrierDthe last check digit for accounting and security purposes
考题
填空题One of the purposes of reforestation projects is to protect the habitat and prevent species loss.____
考题
单选题The furnace of an oil fired boiler should be （） before the operating burner is lit.A
filled with waterB
purgedC
cleared of airD
None of the above is true
考题
单选题A dazzling white burner flame in the boiler furnace indicates （）.A
no combustionB
deposits in the fuelC
excessive air in the fuelD
cold fuel oil
热门标签
最新试卷
