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Mechanical Engineering
Mechanical Engineering is a branch of engineering that encompasses the generation and application of heat and mechanical power and the design, production, and use of machines and tools. Mechanical engineering involves application of the principles of dynamics, control, thermodynamics and heat transfer, fluid mechanics, strength of materials, materials science, electronics, and mathematics.
10,989 Questions
How does rolling ring drive works?
The inner race of a "rolling ring" bearing is specially contoured to form a central "ridge" which runs around the entire inner race surface of the bearing.
When mounted on a shaft of rolling ring drive, a rolling ring bearing contacts the shaft only on the apex of this central ridge. The bearing may be "pivoted" left or right on the shaft, and still maintain point contact with the shaft.
In a rolling ring linear drive, an assembly of three or four rolling ring bearings is fixed and compressed within a housing. A smooth, threadless shaft is inserted through the housing, and through the rolling ring bearing assembly.
When the rolling ring bearing assembly is angled on the smooth shaft, and the shaft is rotated, compression against the central ridge surface is generated causing the bearings to "roll" along the length of the shaft. The rotary motion input provided by the motor-driven shaft is thereby converted to linear motion output. The housing, which bears the payload, moves along with the rolling ring bearing assembly. The angle of the rolling ring bearing assembly, relative to the shaft, determines travel direction and pitch (distance traveled per shaft revolution).
No backlash -- Advantage over precision ball screws
Backlash is inherent to ball screw design. It results from the amount of clearance between the ball bearing and the threads. Backlash is caused by clearance or "play" between contacting surfaces in ball screws, gears, belt drives and other linear motion devices. To overcome backlash, ball screw users typically preload the nut to keep the balls under steady pressure. Other methods for fighting backlash include active cam mechanisms, shims and other devices which load the geartrain. These methods can be expensive. And their performance level deteriorates over time due to wear and tear. Okcoil rolling ring drives require no preload to eliminate backlash. Rolling ring engineering assures continuous point-contact between the rolling ring bearing surface and the shaft. There is no "play" and virtually zero backlash - even during reversal. Additionally, rolling ring drives ( trvaverse units) have built-in overload protection. If the system is overloaded, the nut will slip, not jam. Ball screws can't match these features. And ball screws require a significant, up front investment to reduce of backlash before the system can be used for precision linear motion control work.
The low pressure steam from the last stage of the steam turbine is condensed so that it can be pumped back to the steam raising units at high pressure, as water. You can't compress steam as it would condense in the compressor. The only way to use steam as a gas in a gas turbine would be if it was supercritical, but this would mean operating at temperatures well above the limits for most engineering materials, and steam at these conditions would be very corrosive. This type of reactor cycle using a gas turbine has been considered using helium as the working fluid, and it may be built as the "pebble bed" reactor, or it may not.
I think you need to understand more of thermodynamics. Read the Wikipedia entry for the "Rankine Cycle", see link below
What type of a simple machine is a screwdriver?
Most say it is a lever, but i know for fact that it is actually considered a wheel and axle.
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I'm in proving this and actually it is a lever because i was just taking a test that asked this question and it did not give me the option of a wheel and axle but it did give me lever.
Edit~
The first person to answer was, in fact, correct. To the person who last improved the answer: Some people consider it a lever; it is actually a wheel and axle.
A lever is a rigid object that rotates around a fixed point, like a seesaw, while a wheel and axle is two circular or cylindrical objects that are fastened together (The handle and the metal rod) and they rotate around a common axis (the screw)!
:)
No single calculator does it all. Since you haven't been through either of the classes yet,
you're not in any position to judge which one can do the job for both classes. And since
you're not made of money, it's unreasonable to expect you to buy both of them.
Here's my opinion. I could be wrong:
I think it's a completely fair, reasonable, and appropriate question to take to the chairmen
of both departments, and say "Look, sir. I have a class in this department and a class in
that department, and they've recommended calculators that are similar but not identical.
I haven't been through either class yet, so I can't judge which one will come closer to
serving my needs for both classes, and I can't afford to buy both of them. May I ask
please that you have these two instructors ... the one from your department and the
one from the other department ... consult with each other, as soon as possible, and agree
on a single calculator that I can use effectively for both of their classes ?"
What is the principle of car jack?
There are at least three kinds:
- hydraulic jack: A pump with a small-diameter piston and cylinder is operated to produce hydraulically pressurised liquid. This liquid is directed again a large piston. Since this piston is larger that the one in the pump, although the force acting on, say, a square centimetre is the same the overall force is much larger and great enough to lift a car.
- scissor jack: The jack is in the form of a four-sided figure with hinges at the corners. A screw is mounted horizontally so that it can rotate at one corner of the square and turn inside a thread at the opposite corner. As the screw tightens it pulls the opposite sides of the four-sided figure together forcing the top of the figure up.
- rack-and-pinion jack: The jack consists of a long, large diameter screw with a threaded hook on it. As the screw is turned the hook is pulled up.
How many watts can be expected form a windshield wiper motor?
It should give you that information on the side of the motor
The first equipment used that actually allowed breathing underwater was invented in 1620 by Englishman Cornelius Drebbel. Designed for use in an oar-powered submarine, it used heated saltpeter to emit oxygen. The resulting potassium hydroxide absorbed the carbon dioxide produced during respiration. This first crude "rebreather" went generally undeveloped for two centuries.
Inventions in 1853 by Belgian T. Schwann, in 1878 by Englishman Henry Fleuss and in 1900 by Englishman Sir Robert Davis, were some of the earliest working self contained breathing gear. These systems were "closed-circuit" designs, meaning that the exhaled gas is retained in the system and made breathable again. These rebreaters all shared the common trait of using pure oxygen as the breathing gas. This limited their use to very shallow water (<30 feet [10M]) due to the toxic effects of oxygen at the increased partial pressures of greater depths. These designs were primarily used, in fact, in rescue and mine safety applications until the 1930s when Italian sport spearfirshermen began to use them for spearfishing.
World War II saw the first military application of oxygen-based rebreather-type SCUBA equipment, first by the Italians using modified spearfishing units and then by the English using designs based on captured Italian units. The German firm Draeger, which had developed a rebreather for mine rescue in 1907, supplied oxygen rebreathers to the German military. All of these oxygen-based systems were limited to shallow water demolition and combat swimmer delivery. American Christian Lambertson developed this concept into the first truly modern military rebreathers beginning in 1939. Lambert's devices were the first to actually be called SCUBA, the wartime code name for self-contained underwater breathing apparatus.
As far as most divers are concerned, however, the real breakthrough in SCUBA came in 1943 by Frenchmen Emile Gagnan and Jacques Yves Cousteau. Modifying a welding regulator into a pressure-sensitive demand regulator and coupling it with three air-filled welding gas cylinders, they invented the first open-circuit SCUBA gear. Open-circuit SCUBA allows the exhaled gas to escape into the water as waste gas. The two Frenchmen eventually sold this equpment under the name "Aqua-Lung" and started a company which became U.S. Divers and is now known as Aqualung International.
The Gagnan/Costeau invention of open-circuit (non-rebreathing) SCUBA using air as the breathing gas allowed the first widespread diving by civilians. The use of air allowed diving to depths far in excess of those allowed by pure oxygen and the open circuit design could be used safely with relatively little training. The Aqua-Lung was the key invention that opened up the oceans to generations of recreational divers.
The first Aqua-Lung designs used a single regulator mounted at the tank valve which delivered air and exhaust gases via two large-diameter corrugated over-the-shoulder breathing hoses very similar to those used by rebreathers. A generation of early SCUBA divers grew up watching actor Lloyd Bridges as Mike Nelson using double hose Aqua-Lung regulators on television's Sea Hunt program.
The first modern two stage, single hose regulator was manufactured and distributed by Divers Supply in Wilmington California in the early 1950s. This design, an offshoot of surface supplied commercial gear, uses a first stage regulator mounted at the tank valve delivering air to mouthpiece-mounted second stage via a small-diameter intermediate-pressure (140 psi [9.6 BAR]) hose. Today, virtually all modern open-circuit SCUBA gear uses this design, though Aqualung did market a "modern" double hose Mistral model in 2005 and 2006.
What is the principle of clamping in jigs and fixtures?
clamp is a holding device. The principle of clamping is " the clamping forceshouldbe strong enough to withstand forces that are caused during machining and clamping force should not be such high that it will damage the work piece".
What is the cost for a Cold Steel Kukri?
If one visit Cold Steel webpage one can find a number of Kukri knives. Their prices go from $29.99 up to $699.99. One can find them too in specialized stores like Turner's Outdoorman.
What is a spectacle blind flange?
"A spectacle blind - also known as a figure-8 blind - is generally a piece of metal that is cut to fit between two pipe flanges and usually sandwiched between two gaskets. A spectacle blind is often made from two metal discs that are attached to each other by a small section of steel. The shape is similar to a pair of glasses or "spectacles" - hence the name spectacle blind. One end of the blind will have an opening to allow flow through the pipe during operation and the other end is solid to block flow during maintenance. They are generally installed as a permanent device to separate process piping systems."[1]
The whole idea of a spectacle blind is so that one can be absolutely sure that an item of equipment is properly and securely blanked off with no possibility of any flow or leakage through a valve during maintenance. The flow can be diverted to other items of equipment but not just bypassed around the blank as this would compromise the safety function of the spectacle blind. The flow has to valved off and pressure relieved prior to loosening flange bolts and swinging the blind.
References
1. Steinmans, LLC, "What is the difference between a spectacle blind and a paddle blind or spade blind?", Online News Article, Web Link: http://spadeblinds.com/ournews/entry?id=6
Are metric and sae wrenches are interchangeable?
NO. -Some of them are interchangeable by total co-incidence, but that's not intentional. These are two completely different size systems.
Where do you check engine compression on a diesel engine?
Depends cummins powerstroke or duramax or even a little TDI Jetta are all different
Is a ohmmeter a pressure gauge?
No. An Ohmmeter measures electrical resistance to the flow of current.
Can tig welders be used without gas?
Yes you will not get a "good" weld and it will not be strong The filler electrode used by TIG welder is usually bare and need a shield gas to shield off the atmosphere. Without shield gas, air gets into the molten weld usually produce defects called porosity (air pocket). Your finished weld is defective may not meet the strength. Without a shielding gas you will need more power to establish an arc and the weld puddle will be extremely contaminated (oxidized). The electrode (tungsten) will also be contaminated. You will find the arc wandering all over the place. Use a stick welder instead!
Tail Shaft is the section after the propeller shaft of a shift. Any shaft is always placed farthest from the head, where the power is applied.
Difference between stainless steel and duplex stainless steel?
dublex ss has 22% or more but ss has 18%cr or less
the main difference is that duplex is a mix of a ferrite / austenite structure approx 50%/50%, and so the name "duplex" while stainless steel has just one structure, for example the 18/10 is an austenitic.
A lapping plate shaped to match the valve seat is used with lapping film or compound. On a large valve, it would be turned with a drill. On a small valve, by hand.
How do you align clutch and input shaft?
Usually there is a tool available for this purpose. If not, it should be made. It is a quick lathe job on a piece of plastic or aluminum.
What is a traversing mechanism?
The act of establishing traverse stations and making the nessary measurements.
How does the hydraulic breaking systems functions?
Thehydraulic breaking system working in the pressure difference system... If the pressure is applied in one end of the small diameter pipe... The opposite side of big diameter pipe the same fluid is pressurised in a higher amount and the force is very high .. So only the small pressure fore given by the leg is applied to the breaking end very higher amount and the breaking is done....
