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单选题
A possible cause for an individual piston to knock when at TDC on a slow-speed, two-stroke/cycle main propulsion diesel engine could be due to （）
A
early fuel injection
B
excessive bearing play within the running gear
C
overloading of the cylinder
D
all of the above
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更多 “单选题A possible cause for an individual piston to knock when at TDC on a slow-speed, two-stroke/cycle main propulsion diesel engine could be due to （）A early fuel injectionB excessive bearing play within the running gearC overloading of the cylinderD all of the above” 相关考题
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Scarcely()when a knock at the door awakened her.
A、she fell asleepB、had she fallen asleepC、does she fall asleepD、has she fallen sleep
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When you ______ at the door, I ______ some washing.A、knocked; didB、was knowcking; didC、knocked; was doingD、knock; am doing
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what chemicals did you use to treat the boiler water ?when you test alkalinity and acidity of water in boiler by pH test paper ? the result shows the boiler water is in acidiity . please describe what the possible cause is .
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If a reciprocating air compressor has a knock occurring in frequency with its operating RPM, the cause is probably _____.A.misalignment or worn main bearingsB.insufficient cylinder lubricationC.defective or poorly fitted valvesD.All of the above
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Insurance (保险) may be considered a game of risk in which individuals and businesses protect themselves, their families, and their property from possible losses resulting from unpredictable events such as storms, fires, accidents and illnesses. The first rule of the game, devised centuries age, is "share the risk". To play by this rule, many people take a small loss in place of one person′ s taking a large one.
It is a simple idea: an individual pays a small amount of money called a premium (保险费) to an agent who acts on behalf of an insurance company, or underwriter, which holds the individual′s premium and the premiums paid by thousands of others. The individual receives an insurance policy, a promise that if there is a loss to the individual as defined in the policy the insurance company will pay for it. The funds will come from the individual′s premium, the premium paid by others who did not have losses, and money from the company′ s investment of all the premiums. An individual who does not have a loss loses the premium money but purchases what insurance underwriters call "peace of mind". It is a gamble for the customer and the underwriter, but it is built on the first rule of risk that losses are small when shared by many.
Which of the following statements is true?A.Premium is a small amount of money you pay for your losses.
B.If an individual didn't have a loss, premium was not wasted, because he didn't need to worry about unpredictable events.
C.An insurance agent holds premiums paid by the thousands.
D.The premium will be refund if an individual does not have a lose.
考题
单选题Hardly I had sat down when I heard someone knock at the door.A
I hadB
whenC
heardD
knock at
考题
单选题In a single acting, four-stroke/cycle diesel engine, the power impulse in an individual cylinder occurs （）A
once every crankshaft revolutionB
once every two crankshaft revolutionsC
once every piston strokeD
twice every piston stroke
考题
单选题Cross scavenging requires the fitting of （） to prevent air or exhaust gas escape when the piston is at the top of the stroke.A
a exhaust valveB
a piston skirtC
a piston crownD
an air suction valve
考题
单选题Insufficient end clearance on newly fitted piston rings in a diesel enginewill cause the rings to（）A
jam in the most worn part of the cylinder when the rings expandB
break in the most worn part of the cylinder when the rings expandC
wear eccentrically on the side opposite the end gapD
overheat and jam at the top center on the combustion stroke
考题
单选题In some diesel engine designs,（）the injection of cylinder oil is timed to impinge when the piston and only impinge on（）A
is coming upward；cylinder ring beltB
is going downward；piston ring beltC
is coming upward；piston ring beltD
is going downward；cylinder ring belt
考题
单选题Incomplete combustion in a running diesel engine can cause piston rings to become stuck as a result of （）A
residual carbon depositsB
lube oil viscosity breakdownC
uneven heat expansion of the ringsD
uneven heat expansion of the piston
考题
单选题Which of the listed conditions can cause lacquer to be deposited on a piston skirt?（）A
High sulphur content fuelB
High lube oil temperaturesC
High vanadium content fuelD
Excessive piston slap
考题
单选题When inspecting piston rings through the ports of a two-stroke/cycle diesel engine, black areas on the sealing surfaces are the result of （）A
insufficient lubricationB
improper piston coolingC
blow-byD
overload operation
考题
单选题When starting an engine, the compressed air enters the cylinder when the corresponding piston is in position of its（）A
suction strokeB
compression strokeC
power strokeD
exhaust stroke
考题
单选题（） is sometimes used for piston cooling since leaks into the crankcase would not cause problems.A
Diesel oilB
Hydraulic oilC
Lube oilD
Mineral oil
考题
单选题In a diesel engine, when the fuel is injected into the cylinder,（）A
the piston is just coming upward from the bottom dead centerB
the piston has moved about one-fifth of the way upC
the piston has moved most of the way up and almost reached the TDCD
the piston has just past the TDC
考题
单选题Persistent knocking of one cylinder of a diesel engine ceases when the fuel supply to that cylinder is securedThis problem may be a result of （）A
low loading of that cylinderB
faulty combustion in that cylinderC
sluggish piston ring actionD
excessive piston cooling
考题
单选题The scavenging air ports are located at （） that they are just exposed by the upper edge of the piston when the piston is in the bottom dead center position.A
so a heightB
such a heightC
so highD
such high
考题
单选题If a reciprocating air compressor has a knock occurring in frequency with its operating RPM, the cause is probably （）.A
misalignment or worn main bearingsB
insufficient cylinder lubricationC
defective or poorly fitted valvesD
all of the above
考题
单选题In a single acting, two-stroke/cycle, diesel generator engine, the power impulse in an individual cylinder occurs （）A
once every crankshaft revolutionB
once every two crankshaft revolutionsC
once every piston strokeD
twice every piston stoke
考题
单选题Many cast iron pistons are designed with heat dams, which serve to （）A
keep piston crown temperatures elevated for smoother combustionB
reduce the possibility of overheating the top compression ringC
help retain the heat of compression to prevent ignition delayD
help retain the heat of compression to prevent combustion knock
考题
单选题For a diesel engine, when the piston is at the （）, the clearance volume is the largest.A
TDCB
DTCC
BDCD
DBC
考题
单选题Excessive piston ring wear in a diesel engine will cause（）A
high lube oil viscosityB
increased lube oil consumptionC
low lube oil temperaturesD
high firing pressures
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单选题What is true when designing OSPF import routing policy in JUNOS software?（）A
Import policies are not possible.B
Import policies only match on external routes.C
Import policies only match on internal routes.D
Import policies can cause inconsistent link state databases.
考题
单选题（） may be the first possible cause which makes the engine to lose power or slow down when it is running.A
Hot bearingB
Starting valvesC
Unequal distribution of loadD
Excessive crankshaft clearance
考题
单选题The engine may lose power or slow down during running, when this occurs, the first cause possible may be hot bearings and （） of the pistons in the cylinders.A
crackB
knockingC
leakingD
seizure
考题
单选题The single acting cylinder is the simplest form where pressure is applied to the full area of the piston head to move the load through piston rod extensionThe load causes rod （） when the drive pressure is released.A
contractionB
retractionC
expansionD
shrinkage
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