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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 are pneumatics better than hydraulics?
Poster below is correct. Air systems typically have a tank that is the analog of a hydraulic reservoir.[ebolton]
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Actually there is need for air reservoir in industrial pneumatics systems.
Hydraulics can handle more powerful aplications than pneumatics for the same overall dimensions, or can be more compact for the same power.
What was the name of the first rocket built?
The first manmade object known to have been placed in Earth orbit was Sputnik 1 - a Soviet satellite. However, the first manmade objects to enter space sub-orbitally were arguably German A4/V2 ballistic missiles. These were being developed and launched from the Baltic island of Peenemunde from before WW2 and several thousand were fired in action before the close of hostilities. The standard A4 missile reached altitudes in excess of 50 miles, long considered the threshold of "space". After WW2 the United States continued to launch them experimentally from White Sands missile range. They created a two stage version, the "Bumper" which climbed to even greater altitudes and would be the safest contender for this title of first manmade object in space. Prior to 1950. It should be borne in mind that the question is rendered ambiguous by the fact that "space" has no distinct beginning. Whilst the International Space Station ( ISS ) orbits at about 200 miles altitude and most manned flight occurs there or lower, the upper regions of Earths atmosphere extend several thousand miles further! It is for this reason, resulting in subtle aerodynamic drag that such low orbits decay if the vehicle is not periodically boosted, as is the ISS by means of Russian Progress and Soyuz vehicles. It can therefore be argued that the earliest manmade objects in space were actually high altitude balloons. It is argued, moreover, that the first man in space was USAF colonel Joseph H. Kittinger, who made the highest human balloon ascent in history aboard Excelsior 3, from which he returned by parachute, on August 16th 1960. The highest parachute drop ever, wearing a space-suit and descending for several minutes before his chute could be opened.
What was the name of the largest tank battle in history?
The Panzerkampfwagen VIII, codenamed Maus("mouse" ... who says the Nazis didn't have a sense of humor?), was the largest tank ever built (as a prototype ... an additional hull without turret was also completed).
Larger tanks such as the Landkreuzer P-1000 Ratte ("rat"), about five times larger than the Maus, have been designed but never actually built. Even the Maus was really too large and unwieldy to be of any real practical use.
How do bicycle reflectors work?
The lens is made up of many tiny geometric shapes that reflect the light back to source rather than let the light through the lens. There is often a silvered coating on the reflector back to enhance the reflective properties of the lens.
How milling differs from lathe turning?
They both have; spindles, bedways, automatic feeds, work holding equipment, although these vary between machines, both can use digital readout, coolant supply, both have heads - where the gears and spindle are housed. I'm certain I've miss out loads but i would be here forever.
What is yield point phenomenon?
If anyone ever tries digging into this phenomena, I'd like to be a little bit of help. Try reading something about the "Dynamic Strain Aging" and "PLC effect". Still if you are lazy and do not prefer it, well, as an unqualified person I'd say it is "...due to the impurities obstructing the dislocations from occuring. These interstitials and etc. just forms non-permanent molecular bonds and keeps the dislocations from moving. When the stress overcomes an impurity site, then it encounters another and this whole thing keeps going like a cycle; and this is the reason of that fluctuation which goes on like till the stress-strain curve reaches its secondary yield point."
p.s. wiki was quite much the thing that Ive learned it all from...
How do you measure a tenth of an inch?
if the qustion is find the length to the nearest 1/2 inch. and this is between 1 1/2 inches and 2 inches is closer to what ? (2) this is your answer because like my teacher told me 5 or more raise the score 4 or less let it rest so there you go wish yah luck !!>bubblez<
Why the water cooled condensers have to be used in the water steam cycle of power plant?
Some of the heat is used to produce electricity, the rest is waste and put into the environment.
Much of the energy of the heat is lost as the steam passes through the turbines, with the heat being converted to mechanical energy, and then to electrical. This accounts for about 35% to 40% of the energy of the heat, cooling it by the removal of that heat.
It would be possible for residual heat to be tapped for conversion into electricity, also, but this is not done in most nuclear reactors. Converting it to electricity would get another 10% or so of the heat of the remaining steam, cooling the steam further.
The remainder of the heat is waste. It is dumped into the environment, primarily into the air, by using heat exchangers and cooling towers. In this system, the steam is used to heat water, condensing in the process. The water is then used to heat air in the cooling tower.
Another way to get rid of waste heat is to use heat exchangers to heat a nearby body of water, such as a lake, the ocean, or a river. This is usually done only in the summer, when the atmosphere is warm and the cooling towers are not efficient enough to do their work.
Credited with the introduction of the steamboat?
The first successful steamboat was in 1807 by the American inventor Robert Fulton. However, John Fitch made the first successful trial steamboats.
Which country has the world's most powerful tank?
Great Britain with the Challenger 2. It has unrivaled armour, firepower, offroad capability and design.
China also currently has the world's next 2 most powerful tanks, the Type 99KM and the CSU-152. Both tanks are on par with each other but are more powerful than other tanks due to their 2100-hp engine, 155 mm gun (the CSU-152 uses 152 mm electromagnetic rail gun), weight, and advanced armor.
The Type 99A2 comes in after the Type 99KM and CSU-152.
Germany, USA, Russia and France also have powerful tanks, namely the Leopard 2A6 and M1A2SEP.
What are the Advantages and disadvantages of electro-pneumatics?
ADVANTAGES OF PNEUMATICS.
1. Simplicity of Design And Control
The control machines are easy to design. i.e they can be manufactured using standard cylinders & other components. Controlling mechanism simply contains two ON-OFF states, so its easy to implement and understand.
Also these components have versatile usage, they can be used in many situations. Pneumatics are easy to install and have useful mechanical movements. For an instance Straight-line movements can be obtained without further adjustments, such as levers, cams...etc
2.Reliability
pneumatic control mechanism is well known for its long lasting operation life time. In fact they need very little maintenance but operates continuously with high reliability.
Air /gas used as the working fluid is less likely to damage the equipments since gas are good in absorption of shock, and excessive forces, but hydraulics react directly transferring the stress to mechanical parts.
3.Safe to use
Pneumatic controls have high safety profile due to many reasons. Air used in these are fire proof, and less vulnerable to explosions and electric hazards. These are adoptable in extreme weather conditions, and we can rely on their continuous operation. This is because compressed air can stay in good condition in high temperature fluctuations, unlike hydraulic s ystems that tend freeze or boil in these situations.
Even a leak occur there is less chance of getting fire. Also there is no toxicity in air used, so we can expect no harm to living beans. Since pneumatics are sound in safety, very less precautions need to be taken.
4.Storage
Compressed Gas can be stored easily, and once compressed, above a certain threshold level they can be operate with out further need of compressing. This feature allows the use of machines when electrical power is lost.
5. Clean
Since working fluid is purified air, there is no messy waste produce at the end of the day. A little leak will not make the surrounding shady. Also, since ir is used no risk of toxic hazards t o machines or humans. Industries like pharmaceutical, food..etc tend prefer pneumatics for their cleanness.
6. Easily transported
Air is easily obtainable from atmosphere and can be used with little purification. Air can be pumped to long distances in pipelines, so can control pneumatic equipments for long distances. This makes central controlling possible. These also requires no return line, so easy to manage and cost effective.
7. Light in weight
Air is very light compared with other fluids, which are very heavy. They don't need high power to transfer.
8.Cost Effective
This is a very economical controlling mechanism. The Pneumatics require low maintenance cost, since wear of equipments are very less. These operates at low pressure , so equipments can be produced for low cost using cheap materials. In contrast hydraulic controlling systems require high pressure, so need tough materials, which comes in high prices.
9 high speed working medium
Compressed air controllers are able to achieve high work speeds, the flow rate may go up to 20 m/s, while hydraulics is restricted around 5m/s.
10.safe operation in Overloads
The shock absorbent properties of air make overloading safe. Under excessive forces air can compress easily avoiding damage to equipments.
11 Variable pressure
Pneumatic systems can work in various pressures, this also alow the speed control.
DISADVANTAGES OF PNEUMATICS.
1. Air is largely compressible, which may be good for some reasons, but the major draw back is the inefficiency in accurate positioning and speed controlling. These often need to be tuned to work correct and sound. Since Compressible,not possible to achieve uniform and constant piston speeds.
2.Unable to work with heavy loads (commonly used working pressure of 7 bar, the require output force is economical only up to about 20 KN to 30 KN ) Unlike hydraulics or electrical system these cant be used for heavily loaded operation.
3. Air used needs to be purified, air containing moisture may lead to corrosion of the equipments.
Can you use compressor as a pump?
what do you want to pump?
i think if we cannot use pump as a compressor or vica versa though technically there principle is same but the design is totally different and if we use them then efficiency will decrease significantly but they can be used if any want
Explain the difference between compressive stress and tensile stress?
Tensile Force -
The force of pulling something apart. An example would be doing a tensile test on piece of steel to check the tensile strength. They put the piece of steel at a specified size in a machine that uses tensile force and pull apart the test sample. They measure the amount of force necessary to break apart the sample. All steel has a minimum standard of tensile strength required to be called this grade of steel. Compressive Force - The force of compressing an object. A common example is a cement sample compression test. Cements best quality is its compressive strength. This is why it is used as a foundation for buildings. Anyways, the test is placing a cement cylinder at a certain size in a compression machine. It basically squeezes the cement or compresses the cement to the point of rupture. Then they record the amount a compressive force it took to rupture the cement sample. It has to meet a minimum standard to be accepted or they reject the product made from this batch.
What are the main areas of maths used in mechanical engineering?
Everything in engineering requires applications of mathematics.
Is this a joke? Mathematics is the QUEEN of the sciences. she RULES engineering. Without math, you have no engineering, any kind of engineering. Think of Mathematics as the Venus of the sciences.
Why a lathe is called an engine lathe?
Lathe is power driven machine,which is used for many operation such as reduction in length,dia and enables threading,surface finishing operations etc which are the basic operations to be carried out for the component.
The friction that two surfaces excert on each other when they rub against each other is called a friction.
What are 10 examples for levers?
Well, there are three classes of levers. Class one levers are seesaws, where the effort force is on one end, fulcrum in the middle and object on the other end moving the opposite direction of the effort force. Class two levers are wheelbarrows, where the effort force is on one end, the fulcrum on the other and the object in the middle. Class three levers are like baseball bats, the fulcrum is on one end, the effort force in the middle and the object on the end. Other examples include: a golf club, catapult, an arm, a door, a tennis racket, a fly swatter or a stick.
What are the defferences between dessel and petrol engine?
Petrol & Gas engines are spark ignited engines where as diesel engines are compression ignited engines. Petrol engines works with explosion of fuel air mixture due to spark from spark plug inside the cylinder. Diesel engines works with combustion of fuel air mixture due to compression, compressed mixture attains a very high temperature which exceeds the flash point of diesel and starts burning inside the cylinder and the hot gases after burning of fuel misture exerts force on piston which makes the diesel engines work. Diesel engines are highly efficient than petrol engines.
What is the definetion scaler quantities?
Scaler Quantities are those which are completely specified by their magnitude
expressed in suitable units without any mention of direction .
Posted by yousufkhan {yousufkhan_1@yahoo.com}
How does a turbine and generator work?
The turbine converts pressure & heat energy (in steam turbine & gas turbine), velocity energy (in hydro turbine) into mechanical energy which produces rotation of the turbine. This mechanical force is used to rotate the rotor(which is coupled with the same shaft as that of turbine) of the generator which converts this mechanical energy into electrical energy.
What is the thermal conductivity of Cast iron?
Thermal conductivity refers to the measure of the ability of a material to allow the flow of heat from its warmer surface to its colder surface. The thermal conductivity of cast iron is 80 Wm-1K-1.
