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    Basically a Pump is used for liquid or fluid to transform it to a much high pressure head while a Compressor is used for gases to transform from low to a much high pressure. From Mechanical Engineering point of view liquid is incompressible so Compressor cannot be used for liquid substances. Posted by AbdulQadir Abba Sheriff on linkedin
  2. 34 likes
    1. What is the difference between scavenging and supercharging ? Ans: Scavenging is process of flushing out burnt gases from engine cylinder by introducing fresh air in the cylinder before exhaust stroke ends. Supercharging is the process of supplying higher mass of air by compressing the atmospheric air. 2. What are the names given to constant temperature, constant pressure, constant volume, constant internal energy, constant enthalpy, and constant entropy processes.Ans: Isothermal, isochroic, isobaric, free expression, throttling and adiabatic processes respectively. 3. In a Rankine cycle if maximum steam pressure is increased keeping steam temperature and condenser pressure same, what will happen to dryness fraction of steam after expansion ?Ans: It will decrease. 4. Why entropy change for a reversible adiabatic process is zero ? Ans: Because there is no heat transfer in this process. 5. What are two essential conditions of perfect gas ? Ans: It satisfies equation of state and its specific heats are constant. 6. Enthalpy and entropy are functions of one single parameter. Which is that ? Ans: Temperature. 7. Why rate of condensation is higher on a polished surface compared to rusty surface ? Ans: Polished surface promotes drop wise condensation and does not wet the surface. 8. How much resistance is offered to heat flow by drop wise condensation ? Ans: Nil How are these questions - please do add comments and if you like them please do share this post on facebook, linkedin, twitter and google plus. 9. What is the relationship between COP of heating and cooling ? Ans: COP of heating is one(unity) more than COP of cooling. 10. How much is the work done in isochoric process ? Ans: Zero. 11. When maximum discharge is obtained in nozzle ? Ans: At the critical pressure ratio. 1. Under what condition the work done in reciprocating compressor will be least ? Ans: It is least when compression process approaches isothermal. For this purpose, attempts are made to cool the air during compression. 13. What is the difference between stalling and surging in rotary compressions ? Ans: Stalling is a local phenomenon and it occurs when How breaks away from the blades. Surging causes complete breakdown of flow and as such it affects the whole machine. 14. Why the electric motor of a fan with backward curved blades is never got overloaded under any condition ? Ans: The maximum power is consumed at about 70% of maximum flow in case'of fan with backward blades. For higher flow, power consumption gets lower. 15. Why the work per kg of air flow in axial flow compressor is less compared to centrifugal compressor for same pressure ratio ? Ans: Isentropic efficiency of axial flow compressor is higher. 16. What is the name given to portion of thermal energy to be necessarily rejected to environment ? Ans: Anergy. 17. What is pitting ? How it is caused ? Ans: Non uniform corrosion over the entire metal surface, but occuring only in small pits is called pitting. It is caused by lack of uniformity in metal. 18. What is caustic embrittlement ? Ans: It is the actual physical change in metal that makes it extremely brittle and filled with minute cracks. It occurs particularly in the seams of rivetted joints and around the rivet holes. 19. Which impurities form hard scale and which impurities soft scale ? Ans: Sulphates and chlorides of lime and magnesium form hard scale, and carbonates of lime and magnesium form soft scale. 20. What is the difference between hard water and soft water ? Ans: Hard water contains excess of scale forming impurities and soft water contains very little or no scale forming substances. 21. Which two elements in feed water can cause corrosion of tubes and plates in boiler ? ' Ans: Acid and oxygen in feed water lead to corrosion. 22. What should be done to prevent a safety valve to stick to its seat ? Ans: Safety valve should be blown off periodically so that no corrosion can take place on valve and valve seat. 23. Why large boilers are water tube type ? Ans: Water tube boilers raise steam fast because of large heat transfer area and positive water circulation. Thus they respond faster to fluctuations in demand. Further single tube failure does not lead to catastrophy. 24. What type of boiler does not need a steam drum ? Ans: Super-critical pressure boiler. 25. Why manholes in vessels are usually elliptical in shape ? Ans: Elliptical shape has minimum area of opening and thus plate is weakened the least. Further it is very convenient to insert and take out the cover plate from elliptical opening. 26. Low water in boiler drum is unsafe because it may result in overheating of water tubes in furnace. Why it is unsafe to have high water condition in boiler drum ? Ans: High drum level does not allow steam separation to be effective and some water can be carried over with steam which is not desirable for steam turbine. 27. Why boiler is purged everytime before starting firing of fuel ? Ans: Purging ensures that any unburnt fuel in furnace is removed, otherwise it may lead to explosion. 28. What is the principle of mechanical refrigeration ? Axis. A volatile liquid will boil under the proper conditions and in so doing will absorb heat from surrounding objects. 29. Why high latent heat of vaporisation is desirable in a refrigerant ? Ans: A high latent heat of vaporisation of refrigerant results in small amount of refrigerant and thus lesser circulation system of refrigerant for same tonnage. 30. What is the critical temperature of a refrigerant ? Ans: Critical temperature is the maximum temperature of a refrigerantrat which it can be condensed into liquid and beyond this it remains gas irrespective of pressure applied. 31. Maximum combustion temperature in gas turbines is of the order of 1100 to 10°C whereas same is around 00°C in I.C. engine ? Why ? Ans: High temperature in I.C. engine can be tolerated because it lasts for a fraction of second but gas turbines have to face it continuously which metals can't withstand. 32. Why efficiency of gas turbines is lower compared to I.C. engines ? Ans: In gas turbines, 70% of the output of gas turbine is consumed by compressor. I.C. engines have much lower auxiliary consumption. Further combustion temperature of I.C. engines is much higher compared to gas turbine. 33. What do you understand by timed cylinder lubrication ? Ans: For effective lubrication, lub oil needs to be injected between two piston rings when piston is at bottom of stroke so that piston rides in oi during upward movement. This way lot of lub oil can be saved and used properly. 34. What is IIUCR in relation to petrol engine ? Ans: HUCR is highest useful compression ratio at which the fuel can be used in a specific test engine, under specified operating conditions, without knocking. 35. In some engines glycerine is used in place of water for cooling of engine. Why ? Ans: Glycerine has boiling point of 90°C which increases its heat carrying capacity. Thus weight of coolant gets reduced and smaller riadiator can be used. 36. Why consumption of lubricating oil is more in two-stroke cycle petrol engine than four-stroke cycle petrol engine ? Ans: In two-stroke engine lub oil is mixed with petrol and thus some lub oil is blown out through the exhaust valves by scavenging and charging air. There is no such wastage in four stroke petrol engine. 37. As compression ratio increases, thermal n increases. How is thermal n affected by weak and rich mixture strength ? Ans: Thermal n is high for weak mixture and it decreases as mixture strength becomes rich. 38. How engine design needs to be changed to burn lean mixture ? Ans: Engine to burn lean mixture uses high compression ratio and the highly turbulent move¬ment of the charge is produced by the geometry of the combustion chamber. 39. Horse power of I.C. engines can be expressed as RAC rating, SAE rating, or DIN rating. To which countries these standards belong ? Ans: U.K., USA and Germany respectively. 40. What is the use of flash chamber in a vapour compression refrigeration cycle to improve the COP of refrigeration cycle ? Ans: When liquid refrigerant as obtained from condenser is throttled, there are some vapours. These vapours if carried through the evaporator will not contribute to refrigerating effect. Using a flash chamber at some intermediate pressure, the flash vapour at this pressure can be bled off and fed back to the compression process. The throttling process is then carried out in stages. Similarly compression process is also done in two separate compressor stages. 41. Why pistons are usually dished at top ? Ans: Pistons are usually hollowed at top to (i) provide greater spa'e for combustion, (ii) increase surface for flue gases to act upon, and (iii) better distribution of stresses. 42. What is the function of thermostat in cooling system of an engine ? Ans: Thermostat ensures optimum cooling because excessive cooling decreases the overall efficiency. It allows cooling water to go to radiator beyond a predetermined temperature. 43. What are the causes of failure of boiler tubes ? Ans: Boiler tubes, usually are made from carbon steel and are subject to (a) high rates of heat transfer,( b ). bending stresses due to uneven heating, especially at expanded or welded joints into headers or drums, © external erosion from burners and flue gas, (d) possible corrosion on the boiler side, and (e) occasional manufacturing defects. Failure may occur due to following reasons : (a) High thermal ratings may lead to rapid failure if the internal fluid flow is reduced for any reason. The resultant overheating leads to a failure by creep, characterised by the bulging of the tube with the eventual development of a longitudinal split. (b ) Fatigue cracking due to bending stresses occur. These are associated with change of section and/or weld undercut, where tubes are expanded or welded into headers. © Failure may arise due to overstressing of a reduced section of metal. (d) Sudden failure of the boiler tube due to corrosion arises from embrittlement of the carbon steel due to interaction between atomic hydrogen from the corrosion process and the iron carbide present in the steel. (e) Defects in tube manufacture, although far from being a regular occurrence, can be a cause of serious trouble. Lamination in boiler tubes or score marks arising from the cold drawing of tubes, give rise to premature failure and may promote corrosion at these regions. 44. What are the causes of failure of superheater tubes ? Ans: Superheater tubes are subjected to the most severe combination of stress, temperature and corrosive environment. In addition to high-temperature strength, resistance to corrosion is also important. For example, low-alloy ferritic steel such as -1/% Cr, 1% Mo would not be used at metal temperatures above 580°C because of inadequate resistance to corrosion and oxidation over a full service life of 100,000/150,000 hr. Failures in superheater tubes may arise from : (a) Prior fabrication history (b ) Faulty heat treatment © Consequences of welding (d) Overheating of the tube metal (e) Gas-side corrosion (f) Stress corrosion (austenitic steels). 45. Why supercritical boilers use less amount of steel compared to non-supercritical boilers ? Ans: Supercritical boilers do not head heavy drum for separation of steam from mixture of water and steam. 46. Out of electric heater and heat pump, which is economical in operation ? Ans: Heat pump. 47. Which furnace burns low-ash fusion coal and retains most of the coal ash in the slag? Ans: Cyclone furnace. 48. How the thickness of thermal boundary layer and thickness of hydrodynamic boundary layer related ? Ans: Ratio of their thickness = (Prandtl number)-1/3. 49. What is the effect of friction on flow of steam through a nozzle ? Ans: To decrease both mass flow rate and wetness of steam. 50. Why gas turbine power plant needs efficient compressor ? Ans: Because a large portion of turbine work is eaten away by compressor and its inefficiency will affect net power output and cost of generation. 51. Why rockets using liquid hydrogen have higher specific impulse compared to liquid hydrocarbon ? Ans: Liquid hydrogen has higher burning velocity. 52. Why axial flow compressor is preferred for gas turbines for aeroplanes ? Ans: Because it has low frontal area. 53. What is the effect of inter cooling in gas turbines ? Ans: It decreases thermal efficiency but increases net output. 54. Why iso-octane is chosen as reference fuel for S.I. engines and allotted 100 value for its octane number ? Ans: Iso-octane permits highest compression without causing knocking. 55. Why thermal efficiency of I.C. engines is more than that of gas turbine plant ? Ans: In I.C. engine maximum temperature attained is higher than in gas turbine. 56. Which are the reference fuels for knock rating of S.I. engines ? Ans: n-heptane and ISO-octane. 57. When effect of variations in specific heats is considered then how do maximum temperature and pressure vary compared to air standard cycle ? Ans: Temperature increases and pressure decreases. 58. Quantities like pressure, temperature, density, viscosity, etc. are independent of mass. What are these called ? Ans: Intensive properties. 59. The amount of radiation emitted per scm per sec is called .... ? Ans: Emissive power. 60. In convection heat transfer, if heat flux intensity is doubled then temperature difference between solid surface and fluid will ? Ans: Get doubled. 61. How you can define coal ? Ans: Coal is a naturally occurring hydrocarbon that consists of the fossilised remains of buried plant debris that have undergone progressive physical and chemical alteration, called coalification, in the course of geologic time. 62. Which pollutant is major greenhouse gas and what is its effect ? Ans: CO is major greenhouse gas and it traps the radiation of heat from the sun within earth's atmosphere. 63. In order to increase efficiency and reduce CO emissions and other emissions, clear coal technologies are receiving major attention. What are these ? Ans: (i) Advanced pulverised and pressurised pulverised fuel combustion. (ii) Atmospheric fluidised bed combustion and pressurised fluidised bed combustion. (iii) Supercritical boilers. (iv) Integrated gasification combined cycle systems. (v) Advanced integrated gasification, including fuel cell systems. (vi) Magneto hydrodynamic electricity generation. 64. What are the important operational performance parameters in design of fuel firing equipment ? Ans: Fuel flexibility, electrical load following capability, reliability, availability, and maintenance ease. 65. What is the differenc between total moisture and inherent moisture in coal ? Ans: The moisture content of the bulk as sampled is referred to as total moisture, and that of the air dried sample is called inherent moisture. 66. Proximity analysis of coal provides data for a first, general assessment of a coal's quality and type. What elements it reports ? Ans: Moisture, volatile matter, ash and fixed carbon. 67. Ultimate analysis of coal is elementary analysis. What it is concerned with ? Ans: Carbon, hydrogen, nitrogen, and sulphur in coal on a weight percentage basis. 68. Explain the difference between AFBC, BFBC, PFBC and PCFB in regard to fluidised bed technologies. Ans: AFBC (Atmospheric fluidised bed combustion) process consists of forming a bed of inert materials like finely sized ash or ash mixed with sand, limestone (for sulphur removal), and solid fuel particles in a combustor and fluidising it by forcing combustion air up through the bed mixture. The gas flows thorugh bed without disturbing particles significantly but gas velocity is high enough to support the total weight of bed (fluidisation). At slightly higher velocity excess gas passes through the bed as bubbles (fluidised bed) and gives the bed the appearance of a boiling liquid. Bubbling fluidised bed combustion (BFBC) has a defined height of bed material and operates at or near atmospheric pressure in the furnace. Pressurised fluidised bed combustion (PFBC) system operates the bed at elevated pressure. Exhaust gases have sufficient energy to power a gas turbine, of course, gases need to be cleaned. In fluidised combustion, as ash is removed some unburned carbon is also removed resulting in lower efficiency. In circulating fluidised bed combustion (CFBC) system, bed is operated at higher pressure leading to high heat transfer, higher combustion efficiency, and better fuel feed. Circulating fluidised beds operate with relatively high gas velocities and fine particle sizes. The maintenance of steady state conditions in a fast fluidised bed requires the continuous recycle of particles removed by the gas stream (circulating bed). The term circulating bed is often used to include fluidised bed sys¬tems containing multiple conventional bubbling beds between which bed material is exchanged. 69. What for Schmidt plot for is used in heat transfer problems ? Ans: Schmidt plot is a graphical method for determining the temperature at any point in a body at a specified time during the transient heating or cooling period. 70. In which reactor the coolant and moderator are the same ? Ans: Pressurised water reactor. 71. Which reactor has no moderator ? Ans: Fast breeder reactor. 72. What are thermal neutrons ? Ans: Thermal neutrons are slow neutrons (having energy below 1 eV) which are in thermal equilibrium with their surroundings. 73. What is big advantage of fast breeder reactor ? Ans: It has rapid self breeding of fissile fuel during the operation of the reactor, and thus, it offers about sixty times the output with same natural uranium resources through ordinary non-breeder nuclear reactor. 74. What is the purpose of biological shield in nuclear plants ? Ans: Biological shield of heavy concrete prevents exposure to neutrons, beta rays and gamma rays which kill living things. 75. Which two elements have same percentage in proximate and ultimate analysis of coal? Ans: Moisture and ash. 76. On which analysis is based the Dulong's formula for the heating value of fuel ? Ans: On ultimate analysis. 77. Which element causes difference in higher and lower heating values of fuel ? Ans: Hydrogen. 78. Which heating value is indicated by a calorimeter and why ? Ans: Gross heating value because steam is condensed and heat of vapour formed is recovered. 79. State the difference between ultimate and proximate analysis of coal ? Ans: In ultimate analysis, chemical determination of following elements is made by weight: Fixed and combined carbon, H, O, N, S, water and ash. Heating value is due to C, H and S. In proximate analysis following constituents are mechanically determined by weight. Moisture, volatile matter, fixed carbon and ash. Heating value is due to fixed carbon and volatile matter. 80. What is fuel ratio ? Ans: Fuel ratio is the ratio of its % age of fixed carbon to volatile matter. 81. How the analyses and calorific values of fuels can be reported ? Ans: It may be reported as (a) as received or fired (wet) basis (b ) dry or moisture free basis © combustible or ash and moisture free basis 82. What is the difference between nuclear fission and fission chain reaction. Ans: The process of splitting of nucleus into two almost equal fragments accompanied by re¬lease of heat is nuclear fission. Self sustained, continuing, sequence of fission reactions in a con¬trolled manner is fission chain reaction. 83. Explain difference between fissile and fertile materials. Ans: The materials which can give nuclear fission e.g. U 35, Pu 39, U 33 are fissile materi¬als. Fertile material itself is not fissionable, but it can be converted to a fissionable material by irradiation of neutrons in a nuclear reactor. 84. What do you understand by fuel cycle in nuclear plants ? Ans: Fuel cycle a series of sequential steps involved in supplying fuel to a nuclear power reactor. The steps include : Mining, refining uranium, fabrication of fuel elements, their use in nuclear reactor, chemical processing to recover remaining fissionable material, re-enrichment of fuel from recovered material, refabrication of new fuel elements, waste storage etc. 85. What is heavy water and what is its use in nuclear plants ? Ans: Water containing heavy isotopes of hydrogen (Deuterium) is known as heavy water. Heavy water is used as a moderator. Heavy water has low cross section for absorption of neutrons than ordinary water. Heavy water slows down the fast neutrons and thus moderates the chain reaction. 86. What is a converter reactor ? Ans: A reactor plant which is designed to produce more fuel than it consumes. The breeding is obtained by converting fertile material to fissile material. 87. Explain nuclear reactor in brief. Ans: A plant which initiates, sustains, controls and maintains nuclear fission chain reaction and provides shielding against radioactive radiation is nuclear reactor. 88. What is the difference between conversion and enrichment ? Ans: The process of converting the non fissile U 38 to fissile U-35 is also called "Conversion". The material like U 38 which can be converted to a fissile material by the neutron flux is called "fertile material". The conversion is obtained within the nuclear reactor during the chain reaction. Enrichment is the process by which the proportion of fissile uranium isotope (U-35) is increased above 0.7% (original % in natural uranium). The concentration of U-35 in the uranium hexafluoride is increased from the 0.7% in natural uranium to to 4%. This is called enrichment and is accomplished in an enrichment plant. 89. Disposal of radioactive waste materials and spent fuel is a major and important technology. How the waste radioactive material is disposed off ? Ans: Nonusable fission products are radioactive and take short/medium/long time for radioactive decay to reach safe level of radioactivity. Accordingly three methods of disposal are : (a) Zero or low radioactivity material is dispersed or stored without elaborate shielding. (b ) Medium radioactivity material is stored for short duration of about 5 years to allow decay of radioactivity. © High radioactive material. They are stored in water for several months to permit radioactive decay to an accepetable low level. 90. Which nuclear reactor uses water as a coolant, moderator and reflector ? Ans: Pressurised water reactor. 91. Which reactor produces more fissionable material than it consumes ? Ans: Breeder reactor. 92. Which reactor uses natural uranium as fuel ? Ans: Gas cooled reacator. 93. Which reactor uses heavy water as moderator ? Ans: CANDU. 94. Which reactor requires no moderator ? Ans: Breeder reactor. 95. Which reactor uses primary coolant as fluoride salts of lithium, beryllium, thorium and uranium ? Ans: Molten salt breeder reactor. 96. Why an increase in area is required to produce an increase of velocity in case of supersonic flow ? Ans: Increase in area for increase in velocity for supersonic flow is required because the density decreases faster than velocity increases at supersonic speeds and to maintain continuity of mass, area must increase. 97. Under what circumstances would there be an increase in pressure in a diver¬gent nozzle ? Ans: For subsonic flow at inlet section of a diffuser a lower velocity and higher pressure will exist at the exit section. For supersonic isentropic flow at the inlet section a higher velocity and lower pressure will exist at the exit but if a shock wave occurs in the diffuser then a higher pressure will exist at the exit. 98. Why water can't be used as refrigerant for small refrigerating equipment ? Ans: The refrigerant should be such that vapour volume is low so that pumping work will be low. Water vapour volume is around 4000 times compared to R- for a given mass. 99. Which parameter remains constant in a throttling process ? Ans: Enthalpy. 100. What is the difference between isentropic process and throttlinglprocess ? Ans: In isentropic process, heat transfer takes place and in throttling process, enthalpy before and after the process is same.
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    ANSYS offers engineering simulation solution sets in engineering simulation that a design process requires. Companies in a wide variety of industries use ANSYS software. The tools put a virtual product through a rigorous testing procedure (such as crashing a car into a brick wall, or running for several years on a tarmac road) before it becomes a physical object. This pdf gives good start to understand and learn ANSYS
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    In second angle, both top and front view are drawn above the x-line whereas in fourth angle its vice versa. In second and fourth angle method, top view and front view overlaps. hence we never use those methods. In first angle method, front view lies above the x-line and top view lies below. vice versa for third angle. As both the views lies on either side of x-line in first & third angle, we make use of these methods.
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    To draw a projection of any object first we need to place this object in any quardrant then fit a source of light in front, above or any angle you want. A shadow will occur in the opposite side of the light source which will represent the projection of that object. Now after drawing this projection, the horizontal plane is to be rotated 90 degree clockwise. in second and fourth angle projection due to this process horizontal and vertical plane will overlap with each other. That's why we can't draw second and fourth angle projection.
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    Dear Sourabh, very good question. Just because of the norms we do this. We consider that horizontal plane rotates in clockwise direction after having projection on it. that's why we use 1st angle and 3rd angle projection. because only in this two quadrants we will get the both views after clockwise rotation of horizontal plane. Yes we can use second angle and fourth angle projection but in that case we need to rotate horizontal plane of projection in counterclockwise direction. Thus both 1st angle and 3rd angle projection will be replaced by 2nd angle and 4th angle projection.
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    The performance test of an IC engine is done to find out the power of the engine at various loading conditions and the fuel consumptions at various loads. The main parameters which are tested are 1.Indicated power 2.Brake power 3.frictional power 4.specific fuel consumption(sfc) when subjected to different loads. Further,tests can also be conducted to compute the surface temperature of the engine,oil/water needed to cool the engine.
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    Well, a compressor compresses a gas and a pump moves a liquid. Compressors are often used in refrigeration applications where gas is transformed into a liquid, so the main task for the compressor is not to move the gas but to compress it to increase its pressure. But role of pump is for displacement of fluid (mainly liquid) by applying pressure.
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    whel! I have Instalation files and user manual! If its intresting for you tell me to send 4 u!
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    Hardness: Hardness is the resistance of a material to localized deformation. The term can apply to deformation from indentation, scratching, cutting or bending. hardness commonly refers to a material's ability to penetrate softer materials. An object made of a hard material will scratch an object made of a softer material.In metals, ceramics and most polymers, the deformation considered is plastic deformation of the surface. For elastomers and some polymers, hardness is defined at the resistance to elastic deformation of the surface. The lack of a fundamental definition indicates that hardness is not be a basic property of a material, but rather a composite one with contributions from the yield strength, work hardening, true tensile strength, modulus, and others factors. Hardness measurements are widely used for the quality control of materials because they are quick and considered to be nondestructive tests when the marks or indentations produced by the test are in low stress areas. Toughness: The quality known as toughness describes the way a material reacts under sudden impacts. toughness is the resistance to fracture of a material when stressed. It is defined as the amount of energy that a material can absorb before rupturing, and can be found by finding the area (i.e., by taking the integral) underneath the stress-strain curve. It can be defined as the work required to deform one cubic inch of metal until it fractures. Toughness, often expressed as the Modulus of Toughness, is measured in units of joules per cubic meter (J/m3) in the SI system and pound-force per square inch (sometimes expressed as in-lb/in3) in US customary units. Toughness is measured by the Charpy test or the Izod test. Both of these tests use a notched sample. The location and shape of the notch are standard. The points of support of the sample, as well as the impact of the hammer, must bear a constant relationship to the location of the notch. Difference: The hardness of a metal limits the ease with which it can be machined, since toughness decreases as hardness increases Toughness is a combination of high strength and medium ductility. It is the ability of a material or metal to resist fracture, plus the ability to resist failure after the damage has begun. A tough metal, such as cold chisel, is one that can withstand considerable stress, slowly or suddenly applied, and which will deform before failure. Toughness is the ability of a material to resist the start of permanent distortion plus the ability to resist shock or absorb energy
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    Casting is a process in which the metal is melted at high temperatures and then poured into a mould to give it the desired shape. There are many casting methods: Sand Casting, DIe Casting, Lost Wax casting. In casting process the newly formed shape sometimes needs extra machining to get the desired surface finish. The cast parts can also incorporate defects because of air bubbles and internal stresses. Casting have some issues with metal selection. All the metals are not suitable for casting. It is sometimes associated with blow, scar, scab etc. errors. Forging is also very old method. Blacksmiths used to do forging with the hammer and anvil from an ancient time. It is the process where metal is heated in different temperature ranges and then hammered to get the desired shape. Depending on the temperature forging can hot, cold or warm. While forging there is a change in the grain structure of the metal which consequently makes it more tough and wear resistant. There are very less porosity and shrinkage defects.
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    This is CVT ppt which is used in Scootie and all terrain vehicle car.
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    The bush material would be of a softer material than the shaft/spindle that runs inside it, often bronze, even oil impregnated bronze. The reasons for using the bush are that the bush will wear out before the bearing or the shaft/spindle, therefore reducing the time and costs of replacing the bearing or shaft. It would usually be sensible to carry spare bronze bearings already made to size to allow for a fast replacement. Usually these bronze bearings would be turned up from a length of bronze bearing material, ask your bearing supplies company for it, and make a few up in one go on the lathe, then label them and put them somewhere you will find them again!
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    The Difference Between Casting & Forging Casting is the process where metal is heated until molten. While in the molten or liquid state it is poured into a mold or vessel to create a desired shape. Forging is the application of thermal and mechanical energy to steel billets or ingots to cause the material to change shape while in a solid state.
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    State difference between AnitiFriction Bearing and Journal Bearing? 1. You can answer this question 2. You can like the best answer 3. You can share the question...
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    CC means Cubic Centimeter, It basically denotes the Volume of Cylinder, whether it may be a car or Bike.Technically it's the Bore Diameter and the stroke length of the cylinder.If a car as 1.8L Engine it's nothing but 1800 cc..Hence More the cc, more the power nd torque.
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    An introduction of mechanisms and machines
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    My understanding is that an anti friction bearing is a roller bearing, it has a point or line contact and a journal bearing supports supports a shaft and has surface contact. I also think speed has something to do with it, roller bearings are lower speed while journal bearing are high speed
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    Washer can increase shear area where the bolt holds, and it eliminate friction and scrathing of both contacting surfaces of bolt head/nut and the surface being bolted
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    Bumo

    pump cfd.jpg

    CFD analysis on centrifugal pump
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    S.K.Das Gupta-I think the question itself needs to be modified as "What is the advantage of providing a bush in a bearing housing in place of bush in a bearing. In fact ,the selection of bush bearing or anti friction bearing in a machine depends on the requirement.For example.in a crank shaft of an engine,the big end bearing can be fitted in two halves only.Hence a bush bearing in two halves is used.There is also a space consideration for the machine as anti friction bearing normally needs more space.Also,for very high speed machines,foil bearings are being used as these are very efficient and having a very long life.These days many bush bearings are being replaced with anti friction bearings to get better life and ease of maintenance.So in a nut cell,using a bush bearing/anti friction bearing depends on the function of the machines,it's operating condition,lubricant requirement,space for bearing mounting and many other factors. Material of bush may be phosphor bronze,gunmetal,cast iron,thermit or white metal,teflon etc.
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    To reduce the stress concentration at the sharp edges of the others shape like rec. sqr. trin. or any other shape. the Best shape is to use spherical shape but it seems not possible . In refineries the big spherical containers are used for storage , but for distribution purpose the cylindrical shape is the most suitable shape. Regards, Aftab
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    http://autocadtutorialsbd.com/ArcAn arc is really nothing more than a portion of a circle, so drafting one is very similar to drawing circles. The biggest difference is that instead of just defining the radial size of an arc, you also need to define where the arc starts and ends. You can execute the Arc command from a toolbar or by typing “arc” at the command line. Auto CAD provides many different options for defining your arc, which you can examine in detail through their help utility. Below, I’ve listed the four most commonly used methods of arc creation, and given a graphic example of each in the example above. The various options can be accessed through the pull down menus or by selecting the appropriate options from the command line as shown above. Three Point Arc (3P):This is the simplest way to draw an arc but it’s also the least exact from a drafting standpoint. You simply select the start, midpoint and endpoint of the arc on screen. Start-Center-End:This works similarly to the Start-End-Radius command above, but you select the center point of the arc on screen instead of typing a radius. Start-End-Angle:This method is the one of most commonly used. You select the start and End of the arc on screen, and then you can give angle of arc to complete the arc. Start-Center-Length:Allows you to pick the start and the center point of your arc, and then complete it by entering the linear distance between the start and end points. Start-End-Radius: This method is the one most commonly used. You select the Start and End of the arc on screen, and then you can either drag the cross hairs or type an exact radius to complete the arc. Start-End-Direction:This method is the one of most commonly used. You select the start and End of the arc on screen, and then you can give direction left, right or top, bottom to complete the arc. EllipseTwo axis values are required for an ellipse. Ellipses can be regarded as what is seen when a circle is viewed form directly in front of the circle. Ellipse is measured in terms of two axes there are major axis and minor axis. You can draw ellipse in various way such as using axis, end option or center option. Draw procedure of ellipse: Command: Ellipse8 Specify axis end point of ellipse Specify other end point of axis (Say essential dimension) 8 Specify distance to other axis (Say essential dimension) 8 Hatch Boundary Hatch by typing H <ENTER> . When you start the command, you will see this dialog box appear: Now you want to pick the area to be hatched swatch box. Pick somewhere when hatch pattern plate say (ANSI, Other Predefined, ISO)Select Hatch then OKAdd pick pointPick Internal point then<ENTER>.Select preview for the hatch are ok but when we do not see hatch so set the scale of the hatch and then finally, see the Preview button to see if this is what you are after, it should match your desire work. Note: When hatch pattern does not match your work what can do you? Hatch Edit Select hatch which you drawRight clickHatch EditChange scalePreview button to see if this is what you are after, it should match your desire work. see more details
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    A jig's primary purpose is to provide repeatability,accuracy and interchangeability in the manufacturing of products. A device that does both functions (holding the work and guiding a tool) is called a jig. An example of a jig is when a key is duplicated, the original is used as a jig so the new key can have the same path as the old one. Fixture is a work holding device that holds, supports and locates the workpiece for a specific operation but does not guide the cutting tool. It provides only a reference surface or a device
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    Depending on the apparatus Torque & RPM may be the measured items and used to determine power. Horsepower vs Torque 850 HP vs 18HP w/ maximum tork @ 0RPM
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    abdalla_19876

    spark-plug.jpg

    From the album Spark Plug

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    Explain why washers are used? You can answer this question. You can like the best answer. You can share the question You can get updates of new questions on Facebook linkedin twitter & google plus
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    We use flat washer to reduce stress exerted by the nut, why we use spring washer where there is vibration to avoid work loose of the nut during operation
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    Recently I was looking at the well known textbook, Mechanical Vibrations by S.S. Rao. I found an interesting problem there that seemed to be worth investigating further. The attached note is the result of that investigation. I challenge all of you to work through the details! DrD TwoSprings.pdf
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    in order to perform VBscripting how much should a person be aware of the knowledgeware work benches. should he know the general functions of knowledgeware or should he be well versed in it?
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    I recall in my early years wondering about 1st and third angle projection. What happen to number two? To practice 3D CAD programs I use a 1947 drafting text book, first published in 1911. I found the best explanation of angle projections I have even come across. "First angle was the norm until 60 years ago. Now 3rd angle is the norm in the US and Canada." I am not sure if the 60 refers to the original 1911 printing or the 7th Ed (1947) that I have. Either way it was been around before all of us even the good DrD. I took a photo of the page. The section continues onto the next page but only adds that expensive mistakes have been made confusing the two systems. Now we make those expensive mistake confusing metric and imperial units.
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    The video of the walking machine is very cool. Great job!
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    I regret to point out that ianbates1 has led us on a wild goose chase with his mathematical presentation. 1. The universal gravitational law, describing the force of attraction between two masses, is not relevant to a discussion of the bending of an I-section. 2. The resulting expression for a, the acceleration, is irrelevant as the beam bending problem is usually applied to static structures. 3. The bending deflection expression, FL^3/(3EI) is relevant for a uniform cantilever tip deflection only, but has no general applicability. 4. The expression for the area MOI, bh^3/12, is for a rectangular section as shown, which has no significance for the I-sect ion. 5. The stress-strain relation through Young's modulus explains nothing about the I-section. Other than that, yeah, sure .... why not? DrD
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    there are a few types of washer but standard washers are generally used to distribute force and to help stop the fasteners working loose. Having said that if your fasteners are too long washers make ideal spacers. Washers also make fastened items look more appealing.
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    blower is a type of fan and blower working like a centrifugal pump. blower have 1.1 to 1.2 pressure ratio on other hand fan have below to 1.1 pressure ratio blower used for high pressure air like in furnaces Fan Blower Definition A fan circulates air around an entire room, or space. A blower circulates the air only on the specific or pointed area. Pressure It is uses less pressure to produce large amounts of gas. It is uses high pressure to produce large amounts of gas. Pressure ratio The ratio of pressure is below 1.1. The ratio of pressure is from 1.1 to 1.2. Air area It provides air in the complete area. It provides air in a specific location or point. Types Axial flow fans. Centrifugal fans. Cross- flow fans. Centrifugal blowers. Positive-displacement blowers. Consists of It consists of a motor and blades, which run of electricity. It consists of a fan, outer cover, inlet, out-let.
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    Bolt vs Screw - Open end discussion The difference in design , forces , uses , material - which to use when and more..... You can answer this question. You can like the best answer. You can share the question You can get updates of new questions on Facebook linkedin twitter & google plus
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    Been designing piping systems since 1962, been involved in the valve industry since 1972 and this is the first time I encountered "FOF"