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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
What metal alloy is gun barrels made of?
most often a firearm's barrel will be made with high quality steel. In some special cases the barrel will be chrome lined or will be made with stainless steel. both of which are used to prevent corrosion, expand the life of the firearm's barrel and to make cleaning easier.
The compound drawing for CO₂ (carbon dioxide) consists of a carbon atom in the center with two oxygen atoms attached via double bonds. The carbon atom is at the center with two oxygen atoms on either side, each connected by two lines (a double bond). This structural arrangement gives CO₂ its linear shape.
Annual salary of a mechanical engineer?
I'm and mechanical engineering STUDENT so i dont have any actual personal basis for this. (P.S. if you guys know of any schools that pay you to go, reply) But I have done a little bit of research and it seems like it depends on market and location and firm size. In Charlotte Nc for example and average engineer level I can expect between 45 and 55k a year depending on firm size, larger firms being able to offer more money and benefits. Of course experience increases salary. An engineer with 20 years experience can expect to see salaries of around 100k again depending on market and firm size. hope this helps.
What is the density of stainless steel?
The density of austenitic steel varies according to the type or grade. For one of the commonly used austenitic steel like Type 304, the density is 8.0g/cm3.
The compression of air in a jet turbine is often approximated as an adiabatic process.
The governing equation is pv^(gamma) is constant in an adiabatic process. Gamma is the ratio Cp/Cv, where Cp is the specific heat for a constant pressure process and Cv is the specific heat for a constant volume process. Combining this with the ideal gas law you can derive the temperature-pressure relationship
T2/T1 = (p2/p1)^(kappa)
where kappa = (gamma-1)/gamma.
Keep in mind that everything has to be in absolute units (e.g. temperature in kelvins and pressure in Pa,absolute.)
For a diatomic gas, gamma=1.4, so kappa=0.286.
Therefore, the final temperature is
T2=T1*(p2/p1)^(kappa)
=213 K * (1000/250)^0.286
= 213 * 1.48658
= 316.6 K.
This is the ideal case. For engineering calculations a lower value of gamma is sometimes used (say 1.3).
What does thermosetting plastic mean?
the structure of thermosetting plastics are
Ø Thermoplastics have long chains which are tangled together in no formal pattern
Ø They have very few cross links which means that when heated they become soft allowing them to bent, pressed and formed into different shapes. Ø They become stiff as they cool
Under the ASTM Method D 323 (Reid vapour pressure), it is the absolute vapour pressure exerted by a liquid at 100°F. The higher this value, the more volatile the sample and the more readily it will evaporate. Unlike distillation data, vapour pressure provides a single value that reflects the combined effect of the individual vapour pressure of the different petroleum fractions in accordance with their mole ratios. It is thus possible for two wholly different products to exhibit the same vapour pressure at the same temperature - provided the cumulative pressures exerted by the fractions are the same. A narrow-cut distillate, for example, may exhibit the same vapour pressure as that of a dumbbell blend, where the effect of heavy fractions is counterbalanced by that of the lighter ones. In conjunction with other volatility data. Reid vapour pressure plays a role in the prediction of gasoline performance.
At what temperature saturated steam turns into superheated steam?
all temperatures above saturated steam is super heated steam.
"Superheated" steam isn't so much a scientific term as a technical term. Steam is more efficient the more energy it has (the molecules have more kenetic energy/are hotter).
During the height of steam locomotive development, the most fuel efficient way to accomplish this was to collect the steam, and then run it through a series of loops that are exposed to the exhaust gases of the original combustion, there-by further heating the steam.
Because the steam receives no further moisture, but received further heat energy, it is considered 'dry' steam. Superheat was a term coined by the engine builders as a way to promote the design as a way to sell their engines.
Because the superheater pipes carried steam pressure, they added additional equipment that had to be inspected as per ICC regulations. Because they also were exposed to the exhaust gas stream, they had a likelyhood of being erroded by the waste fuel being exhausted as well as the 1300+ degree combustion exhsut gasses.
Why the phase space fluid is incompressible?
let \rho is density of phase fluid and v is velocity of phase fluid (velocity in a phase space!!)
we take the equation of continuity (we suppose "mass" of phase fluid is conserved) and using Hamilton equations (we suppose classical mechanical system)
[ dot{p_i} = -frac{partial H}{q_i} ]
[ dot{q_i} = +frac{partial H}{p_i} ]
we obtain the result
[ frac{mathrm{d}rho}{mathrm{d}t} = - rho,mathrm{div},v = -rho sum_i left( frac{partialdot{q_i}}{q_i} + frac{partialdot{p_i}}{p_i} right) = 0 ] let \rho is density of phase fluid and v is velocity of phase fluid (velocity in a phase space!!)
we take the equation of continuity (we suppose "mass" of phase fluid is conserved) and using Hamilton equations (we suppose classical mechanical system)
\[ \dot{p_i} = -\frac{\partial H}{q_i} \]
\[ \dot{q_i} = +\frac{\partial H}{p_i} \] we obtain the result
\[ \frac{\mathrm{d}\rho}{\mathrm{d}t} = - \rho\,\mathrm{div}\,v = -\rho \sum_i \left( \frac{\partial\dot{q_i}}{q_i} + \frac{\partial\dot{p_i}}{p_i} \right) = 0 \]
How do you change a boiler from low pressure to high pressure?
YOU DON'T the ASME /NBBI codes have certain requirements regarding boiler manufacturing and a high pressure boiler can cause severe damage if it is not properly designed and routine maintenance performed ....
What metals aren't suitable to be used as pipes?
Metals such as lead, mercury, and cadmium are not suitable to be used as pipes due to health risks associated with leaching into the water supply. Additionally, metals that easily corrode, like aluminum and magnesium, may not be ideal for long-term pipe use.
To find the final temperature, we can use the ideal gas law. First, calculate the initial specific volume of the mixture using the quality of the saturated steam. Then, use the equation of state to find the final specific volume at the new pressure. Finally, determine the final temperature using the final specific volume and the new pressure.
Why are aluminum can recycled more often than steel cans?
Aluminum is easier and cheaper to mass produce than is steel. If you recycle aluminum, you get more money for aluminum than for steel only because manufacturers have for decades focused on aluminum as the cheaper way to manufacture so many things. Aluminum is lighter in weight; is more easily bent into desired shapes; can be easily separated from other metals (chemical process); and is easily shipped to manufacturing plants. As one example, in the earlier days, airplanes contained steel and were heavier, cost more in fuel, etc. Now, all airplanes are made of aluminum shells, are lighter in weight, use less fuel because it is lighter in weight, and all of the aluminum can be recycled. Same with automobiles.
What is sound velocity in grey cast iron?
The sound velocity in grey cast iron typically ranges from 2400 to 3100 m/s, depending on factors such as microstructure, composition, and temperature. It can be affected by the presence of graphite, as well as the amount and distribution of other constituents in the material.
Why the gas turbine needs 3 bucket stages only in 110MW TURBINE?
The 3 bucket stages in a 110MW gas turbine are designed to efficiently extract energy from the high-pressure hot gas produced by combustion. By using 3 stages, the turbine can effectively expand the gas across multiple stages, thereby maximizing energy extraction and overall efficiency within the power plant. Additionally, the design may also optimize the velocity and pressure of the gas flow to ensure proper turbine performance at the specified power output level.
Thread size refers to the diameter of a threaded rod or pipe. In the case of 0.125 Inch NPT thread, the 0.125 Inch refers to the nominal inside diameter of the pipe that the thread will fit into. This means that the thread is designed to fit a pipe with a 0.125 inch inside diameter.
What are the consequences of low alkalinity in boiler water?
Low alkalinity in boiler water can lead to increased corrosion of metal surfaces, as alkalinity helps to maintain a stable pH level. This can result in damage to the boiler components and decreased efficiency of the system. Additionally, low alkalinity can also lead to foaming and carryover in the boiler, which can cause operational issues and reduce the overall effectiveness of the boiler.
What is the value of a 38 caliber chief stainless steel snub nose revolver?
Open the cylinder and look at the yoke for a model number. S&W has made many 38 Special revolvers (which designates the cartridge, not the model). For a value, you will need model, serial number (for age), and NRA condition.
What are the types of high temperature degradation of materials?
The types of high temperature degradation of materials include oxidation (reaction with oxygen), thermal decomposition (breakdown due to high temperatures), and creep (time-dependent deformation under constant load at high temperatures). These processes can lead to changes in material properties and ultimately failure.
What are the advantages of casting over other metal working methods?
A casting may be defined as a " metal object obtained by allowing molten metal to solidify in a mold ", the shape of the object being determined by the shape of the mold cavity. Certain advantages are inherent in the metal casting process. These often form the basis for choosing casting over other shaping processes such as machining, forging, welding, stamping, rolling, extruding, etc. Some of the reasons for the success of the casting process are: ; The most intricate of shapes, both external and internal, may be cast. As a result, many other operations, such as machining, forging, and welding, can be minimized or eliminated. ; Because of their physical properties, some metals can only be cast to shape since they cannot be hot-worked into bars, rods, plates, or other shapes from ingot form as a preliminary to other processing. ; Construction may be simplified. Objects may be cast in a single piece which would otherwise require assembly of several pieces if made by other methods. ; Metal casting is a process highly adaptable to the requirements of mass production. Large numbers of a given casting may be produced very rapidly. For example, in the automotive industry hundreds of thousands of cast engine blocks and transmission cases are produced each year. ; Extremely large, heavy metal objects may be cast when they would be difficult or economically impossible to produce otherwise. Large pump housing, valves, and hydroelectric plant parts weighing up to 200 tons illustrate this advantage of the casting process. ; Some engineering properties are obtained more favorably in cast metals. Examples are: : :: More uniform properties from a directional standpoint; i.e., cast metals exhibit the same properties regardless of which direction is selected for the test piece relative to the original casting. This is not generally true for wrought metals. :: Strength and lightness in certain light metal alloys, which can be produced only as castings. :: Good bearing qualities are obtained in casting metals. ; A decided economic advantage may exist as a result of any one or a combination of points mentioned above. The price and sale factor is a dominant one which continually weighs the advantages and limitations of process used in a competitive of enterprise. There are many more advantages to the metal-casting process; of course it is also true that conditions may exist where the casting process must give way to other methods of manufacture, when other processes may be more efficient. For example, machining procedures smooth surfaces and dimensional accuracy not obtainable in any other way; forging aids in developing the ultimate of fiber strength and toughness in steel; welding provides a convenient method of joining or fabricating wrought or cast products into more complex structures; and stamping produces lightweight sheet metal parts. Thus the engineer may select from a number of metal processing methods that one or combination, which is most suited to the needs of his work.
Why are most gas containers cylindrical in shape?
In brief The most efficient shape for withstanding high pressure is a sphere but that would be costly to manufacture. A cylinder with a domed top and a domed bottom (look underneath, the flat base is actually welded around the outside, the bottom of the gas container is actually domed) is a much cheaper shape to manufacture whilst still having good stength to resist the internal gas pressure.
Some other ideas
The idea that "cylindrical vessels have minimum surface area to volume ratio and thus reduces heat transfer" is incorrect. The surface area to volume ratio for a cylinder depends on the ratio of its length to its diameter and most cycinders are manufactured with a much greater length than is ideal for minimising surface area. In fact a cube would be a better shape than most gas cylinders if this was the primary design consideration. Also heat transfer is actually often a good thing for gas containers, liquids require heat to convert to gases. Try using a butane cylinder on a near freezing day......
The idea that "they are cylindrical because there are no weak points such as joins and corners that the gas molecules could force apart" is partially correct, a cylinder with hemisperical ends has no corners which would certainly act as stress concentrators and therefore be much weaker for the same material thickness but many low to mid pressure gas containers are welded from sheet material so there are joins.
What are round bottom flasks used for?
Round bottom flasks are commonly used in chemistry laboratories for heating liquids evenly during distillation, refluxing, and chemical reactions. The round bottom design allows for efficient mixing and evaporation, making them ideal for applications where a uniform heat distribution is essential.
Are there any types of metal alloys?
Several. Ferritic, Austenite and Martensitic which can be further broken down into different types.
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Austenite has the highest degree of corrosion resistance, ferritic has the best machinability while martensite is the most suitable for objects that need to be hardened.
Some examples of martensitic stainless steels are 440c, Ats 34, Cpm s30v.
What is FCC FCC means Face Centered Cubic Ductility is the mechanical property of a material.It is the material's ability to deform under the tensile stress without fracture.So it is depends on the atoms how they arranged in a lattice and its grain size. The ability to absorb the energy of the impact and fracture resistance depends on the arrangement of the atoms in a lattice and features of grain structure.
