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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
Why are properties of materials important to engineers?
It's very simple: If you use a material with lower strength or hardness, your entire project could collapse on itself. I'm reminded of a US bridge in which a contractor used the wrong metal for metal struts connecting the cement beams. The bridge collapsed, throwing dozens of vehicles into an icy river; many people died. The bridge tore itself apart under tons of weight, simply because the wrong strength of metal was used.
Roughly 15.6 mils or 15.6 thousandths of an inch. Roughly, 1 gauge = .86 mils.
What is the difference between switch and limit switch?
rectifier diodes handle larger amounts of power. A switching diode handles much less amperage but at a quicker rate. There are switching diodes that can switch power on and off in several nano-seconds.
What are the causes of gas turbine failure?
due insufficient jock oil pressure or differential temperature in between top and bottom of casing is not within limits or due sudden drop in gland steam temperature drop due to water injection in LT header of PRDS
there are two types of pneumatic comparators. 1 is a back pressure type and the other is the flow velocity type. in back pressure type- comparators use air pressure to sense changes in dimension.
A pleathorea of sounds, just go trackside and listen, from the piercing note of a horn, to the roar of the diesel engine to the click-clack of the wheels on the joints in the rail to the squeal of steel wheel on steel rail, there are hundreds of sounds to enjoy. "Choo Choo" doesn't cut it, sorry. Only the ignorant can agree that any train ever made this sound.
How does a pulley system on a crane work?
A crane is a lifting machine, generally equipped with a Winder(also called a wire rope drum), Wire_ropeor Chainand Sheave_(mechanical), that can be used both to lift and lower materials and to move them horizontally.
Is R404 freon compatible with R22?
No! Answer No, it will run at a much higher pressure and will probably blow your safety valve. Of course, the answer to your question regarding compatibility could be taken another way. There are mixtures on the market for automobiles with r-22 in them. Chemically it's not a problem, but the pressures are so much higher that to REPLACE r-12 with r-22 would be guaranteeing a system failure. Mixtures for cars with r-22 in them also have other (much lower pressure) components to help control the high pressure of the r-22. In fact, despite the inherent problems with MVAC (leaks and fractionization), mixtures of refrigerants offer more efficient utilization of the condenser and evaporator surface area. Each refrigerant has it's own 'sweet spot' pressure / temperature for condensation and vaporization If you are running a mixture of refrigerants, each will find it's own sweet spot in the condenser and evaporator, allowing for a number of sweet spots for each refrigerant. When you run one refrigerant, you will get basically one sweet spot per heat exchanger.
What is the difference between an automobile and a locomotive?
Automotive = Automobile + Auto Components
Automobile - all types of commercial/passenger vehicles including 2/3/4 wheelers
Auto components are the parts used to manufacture the an automobile
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Does mild steel resist corrosion?
The corrosion rate of a metal is a function of many factors like:
-fluid to which the metal is exposed (chemical composition, concentration..)
-temperature
-flow velocity
-time of exposure
so it's not possibile to give a simple answer
there are three basic means of power transmission
mechanical
electrical and
fluid power
All these three are power transmission mediums
mechanical - short distance very advantageous.
electrical - long distance eg: hundreds of kilometres of electric grids.
hydraulics - greater distance than the mechanical and shorter than the electrical
They mostly substitute the mechanical power transmitters.
Here there are no moving links as in mechanical medium only moving medium that is fluid.
very high force multiplication possible.
only fluid power capable of giving constant force or torque output at various speeds.
they have very high power to weight ratio than there mechanical counterparts.
a simple, compact, reliable, safe system possible only with fluid power.
their control is very simple.
What is the equivalent standard for EN 10060?
What is the euivalent grade of steel for EN 10060:2003, R190J
How is the electricity generated in a coal-fired power plant?
Coal is made from dead plants.
In the United States a little about 50%. See http://www.eia.doe.gov for more details.
Simplest version:
Burn the coal, which generates heat. Use the heat to boil water. The steam from the boiling water forces blades on a generator fan to turn, which turns the generator. Electrical current is then produced. This is a gross oversimplification, but you get the point.
More detailed version:
- A machine called a pulverizer grinds the coal into a fine powder.
- The coal powder mixes with hot air, which helps the coal burn more efficiently, and the mixture moves to the furnace.
- The burning coal heats water in a boiler, creating steam.
- Steam released from the boiler powers an engine called a turbine, transforming heat energy from burning coal into mechanical energy that spins the turbine engine.
- The spinning turbine is used to power a generator, a machine that turns mechanical energy into electric energy. This happens when magnets inside a copper coil in the generator spin.
- A condenser cools the steam moving through the turbine. As the steam is condensed, it turns back into water.
- The water returns to the boiler, and the cycle begins again
Coal is burnt and heats water. Water vapor makes a turbine move and generates electricity. When the coal is burnt, poisonous gases are diffused but has no entry in making electricity and pollutes the air.
A coal-fired power station, burns coal to heat water so that it turns into steam. The steam is used to turn turbines. The turbines spin generators which generates electricity. A generator operates by moving coils of wire in a magnetic field, as the wires move, electricity is generated within the wires.
Traditionally, coal is burned to produced heat, gasses, and solid waste. The heat is used to boil water. The steam produced turns a turbine which turns a generator. The generator produces electricity. That technique has an efficiency of 40%. China claims it has developed a technique with 60% efficiency. It will be interesting to find out what it is. China has also claimed that it has discovered an inexpensive way to remove Carbon Dioxide from coal fired electric plants. If so, that is a fantastic break through.
burning coal is used to boil water. The steam the pushes turbine blades, turning the turbine. The turbine is connected to a generator which produces electricity.
-- Coal is burned in air, releasing heat.
-- The heat is used to boil water.
-- The steam is directed through turbine vanes.
-- The turbine spins an electrical generator.
Why are airplanes made of aluminum?
Aluminum is very lightweight for its strength. This makes it an ideal material for airplanes where every extra pound of weight means one less pound of payload.
Many modern aircraft are now being made of composite materials which are even lighter (and stronger) than aluminum.
What is ASTM equivalent of Q235-A?
Please we need to know the equivalent material ASTM Steel for Q235B.
Mechanical properties of grey cast iron?
if the cast iron consists of carbon in its free state then it is called a grey cast iron mechanical properties of grey cast iron
tensile strength - 270 - 400 N/mm2
Brinell hardness number - 207 - 320
Modulus of elasticity - 1*105 N/mm2
poisson's ratio - 0.23
modulus of rigidity - 0.350 * 105
Oil is used in industrial hydraulic system because?
oil is used in industrial hydraulic system because
Single Pulley
How did the internal combustion engine change America?
With the use of steam power, factories could be built near natural resources and where the work force was. Factories started to grow all over England and then spread to the rest of the world. Cities became more populated because the factories offered a lot of jobs. Work in the factory was more reliable than work in the fields due to the fact that farming was dependent on the weather and crops often failed. The steam engine could now make machines in the factories produce materials much faster. By the early 1800's there were hundreds of steampowered machines in the factories. Steam ran the machines in textile mills and other types offactories. In the 1820's lighter and simpler steam engines were made that could be used in small mills and stores and not just large factories.
The alloy used for welding should be similar in strength to the bulk material being welded. Otherwise there will be stress concentration at the junction between the two alloys. This problem is somewhat reduced when the metals mix during welding, if the weld point moves slowly enough.
How is tensile strength of a metric bolt identified?
Many High Tensile bolts will have a number of raised strokes formed in the head of the bolt. Three or five are common and usually form a reverse triangle or reverse heptagon
What math used in Mechanical Engineering?
First off, the question should be either "What math is used in Mechanical Engineering? or What is the highest level of math someone needs to take in order to become a Mechanical Engineer?"
Most college programs require through Differential Equations to earn a BS degree in ME. This means you would need to take Calculus 1, 2, and 3, Linear Algebra, and Differential Equations once you get to college. It is assumed that most students going into engineering will have no less than Pre-Calculus before entering college while most will have taken Calculus. Now each college has different requirements for fulfilling the math requirements for an engineering program. I know from my experience, Georgia Tech teaches math differently than most colleges because they combine Calc 1-3 and Linear Algebra into just 3 courses instead of 4.
My suggestion is look at the program requirements at the school you are interested in first. Second, evaluate whether you feel that you can learn the math. For those who struggle with math, if you really want to be an engineer, I suggest going to a smaller school where the class size will be smaller. This will have better student/teacher interaction so you can get more help.
Why is the internal resistance of a cell not constant?
The internal resistance of a cell is not constant because a cell needs to move and be flexible in order to undergo various osmosis or diffusion processes.
What is pump head calculation in HVAC?
This is the calculation for how much static pressure shall be created by the pump to flow the water in chiller loop or for the pump to flow the water for cooling tower cycle.
How do you calculate coefficient of linear expansion of copper?
dL/dT = αL*L, where L is the length of the steel, T is temperature, and αL is the linear thermal expansion coefficient which for steel is about 11.0 to 13.0.
That is possibly the easiest differential equation in history:
(1/L)dL = (αL)dT
ln(L) = αLT
L = eαLT
