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If the compensating needle valve of a hydraulic governor is opened more than necessary the governor will ()
A . have a larger than normal dead band
B . produce excessive speed response to a load change
C . respond slowly to any change in engine load
D . stabilize engine speed at the new governor setting
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If the dispersion of a given fiber is 17ps/nm*km at 1550 nm and zero at 1310 nm, then what is the accumulated dispersion of an ITU wavelength after it travels 200 km?()
A . 0 ps/nm
B . 340 ps/nm
C . 200 ps/nm
D . 3400 ps/nm
E . More information is needed.
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One function provided by a hydraulic accumulator is to()
A . provide an area where air can separate from the oil
B . provide an area to separate solid contaminants from the oil
C . act as an oil and water separator
D . absorb shocks occurring in the system
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In a fixed displacement axial piston hydraulic motor, the speed is varied by()
A、regulating the ratio between torque and speed via the torque limiter at the motor
B、directing the motor output flow through a bypass line
C、maintaining a constant flow and pressure input
D、controlling the input flow rate
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An orifice-check valve placed in a hydraulic system is used to()
A . regulate the fluid flow in either direction
B . restrict movement of hydraulic fluid in one direction, but allow free movement in the other direction
C . allow free movement of hydraulic fluid in both directions
D . allow a restricted fluid flow in one direction only
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Water accumulation in the cylinder of a secured engine is an indication that the ()
A . soft water pump was not secured along with the engine
B . jacket water thermostat has failed
C . cylinder liner may be cracked
D . raw water pump is over-speeding just prior to engine shutdow
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The purpose of the compensating adjustment used in a diesel engine hydraulic governor is to ()
A . compensate for low oil level
B . increase governor promptness
C . prevent governor hunting
D . limit engine load
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The major cause of trouble in a mechanical-hydraulic governor is contamination of the hydraulic fluid by ()
A . dirt
B . fuel oil
C . governor cooling water
D . fuel oil tar
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As for a hydraulic single action vane pump, the inner wall of the stator is usually of () shape.
A . circular
B . elliptical
C . rectangular
D . hexago
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Before doing any work on a hydraulic system equipped with accumulators, you should()
A . drain the accumulators and purge with oxygen
B . bleed off all stored energy from the accumulators completely
C . charge the accumulators to prevent system energy loss
D . pump the hydraulic fluid into the accumulators to prevent fluid lo
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Since accumulations of H2S gas on a ship can be dangerous to personnel,it is important to know that H2S gas is().
A . lighter than air
B . heavier than air
C . a yellow gas that is easily recognized
D . mildly toxic
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A hydraulic machine is one that uses () to do work.
A . liquid
B . steam
C . gas
D . electricity
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When normal operating pressure is applied to the hydraulic oil used in a high-pressure system, the oil ().
A . viscosity will decrease
B . volume will increase
C . volume will decrease
D . pour point will be reduced
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For many years marine centrifuges were designed for () operation, that is the machines were run for a period during which solids accumulated in the bowlThe machine was stopped when the accumulated solids began to impair its performance.
A、purifying
B、batch
C、long period
D、temporary
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If a hydraulic pump is overheating, the cause may be ().
A、excessive internal leakage in the pump
B、low discharge pressure and fluid flow
C、excessive fluid level in the hydraulic reservoir
D、operation of the pump at 100% efficiency
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When the desired rudder angle is attained by a typical double mm electro-hydraulic steering gear,the().
A . ram relief valves bypass oil to stop rudder movement
B . six-way valve shifts to the neutral flow position
C . steering pump electric motor is de - energized by the transfer switch
D . follow-up gear takes the hydraulic pump off stroke
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A pumproom is suspected of accumulating gases after a ventilation machinery breakdown. Where should the combustible gas indicator case be placed when testing the pumproom atmosphere for combustible gases? ()
A . In the lower level of the pumproom
B . In the middle level of the pumproom
C . In the upper level of the pumproom
D . On the deck outside the pumproom
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Fuel injection uses the jet pump system and a Woodward type hydraulic () is used to control engine speed.
A . controller
B . governor
C . instrument
D . apparatu
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If the pump for a hydraulic anchor windlass is overheating, the cause may be ().
A . excessive drive motor speed
B . excessive pump discharge pressure
C . too low of a tilting box angle
D . insufficient drive motor speed
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Water allowed to accumulate in the hydraulic system oil will cause an oxidation process producing by- products which are normally ().
A . gums, acids, and varnishes
B . removed by cellulose type filters
C . neutralized by oil additives
D . not removed by absorbent filter
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Obesity is a medical condition in which excess body fat has accumulated to exceed 25% of the standard body weight.
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Obesity is a medical condition in which excess body fat has accumulated to exceed ( ) of the standard body weight.
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A graphical display of accumulated costs and labor hours for both budgeted and actual costs, plotted against time, is called a(n) _____.
A . Trend line.
B . Trend analysis.
C . S curve.
D . Percent completion report.
E . Earned value report.
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When the relief valve is used as a constant pressure valve, it is connected to the outlet of the hydraulic pump to ensure that the outlet pressure of the hydraulic system (pump) is constant.
A:正确;
B:错误