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  1. 2 points
    It could be that I'm going blind but I didn't see the word 'better' in any part of the question!
  2. 2 points
    I was drawing the diagram of the cycle and I could notice that the flash chamber creates a decreasing both the Entropy and Temperature to send the leaving one-stage vapour, to the high-pressure compressor. With the purpose of increase the COP and decrease the compressor power input.
  3. 2 points
    Lisho Thomas

    Why tyres are made black in color?

    Tyres are mixture of various rubbers with carbon black added. Carbon black improves traction and wear resistance of pure rubber. Another reason is that black color has higher absorption capability by which the tyre of any vehicle becomes adhesive to road
  4. 2 points
    Mechanical Engineering is passion or liking..... I really don't know how to explane ..... this is like some one is poet or writer .... very interesting field and never ending ... keeps you fit in this world
  5. 1 point
    Even if I agree with your points, I don't think that they are decisively. I don't have an example either can't prove it, but I guess it's possible to achieve the same properties with changing the color. Maybe a simple answer is better to answer why this variable is always chosen: roads are dirty and the tire surface is submit to high attrition that makes easier to dirty. Black is the best color to not contrast the usual particles and try to make it appears that, even with some particles covering the surface, it is the same color when totally clean (but colors are not good to avoid this particles to reduce the brightness of the tire). Sure it is very convenient that black rubber has the better properties for this application.
  6. 1 point
    1. Moment is a general definition - Moment wikipedia 2. Torque - is related to the move 3. Bending moment - related to construction in mechanic 4. Torsional moment - also is related to constructions, but in another plane
  7. 1 point
    Hello! Today i share some document for Engineering. Visit at: https://dochelp.net/category/engineering/1.html
  8. 1 point
    (lapping ) It is a controlled mechanical sanding or polishing process that involves an abrasive between two surfaces that are rubbed together to create an accurate finish on a part. Depending on the material and application for the part, lapping can be one sided or two sided. It can be used to create a specific surface roughness. For Metal Cutting and our customers, the primary goal of lapping is to achieve a very accurate flat surface; however, lapping can also be used to obtain a domed surface, such as a convex lens or mirror. The process of lapping can be applied to a wide range of materials, including metal, glass, ceramic, plastic, or silicon substrate. Thanks to the precision with which material can be removed, lapping can produce surface finishes in the nanometer (or 0.001 μm) range. ( Honing ) machines are metal abrading tools and process utilizing hard tooling and perishable abrasives stones for the correction of Diameter Shape Surface finish Positional tolerances of bores The hone process was developed to allow for perfection of bore geometry, size control, final surface finish and surface structuring. The honing process provides the final sizing and creates the desired finish pattern on the interior of tubing or cylinder bores. Finishing is accomplished by expanding abrasive stones of suitable grit and grade against the work surface. The stones are rotated and reciprocated in the part with hone abrasive under controlled pressure. Combining rotation and reciprocation produces a cross-hatch pattern in the surface of the part being honed.
  9. 1 point

    What is meant by quality of steam?

    Steam quality is the proportion of saturated steam (vapor) in a saturated condensate (liquid)/ steam (vapor) mixture. A steam quality of 0 indicates 100 % liquid, (condensate) while a steam quality of 100 indicates 100 % steam.
  10. 1 point

    Jigs and fixtures

    From the album Engineering images 10

    What are Jigs? Jigs are the work holding device which holds, supports and locate the workpiece and guides tools to perform a specific operation. In other words we can say that, jigs are the device which is used for both purposes of holding the workpiece and guiding the tool. It is a tool which is used to control the location and motion of the tool during the operations. Jigs main purpose is to provide repeatability, accuracy and interchangeability in the manufacturing of products. It is used in the unidimensional machining i.e drilling, taping, reaming etc. Jigs are found to be light in weight and have complex designing. In jigs, gauge blocks are not necessary and the cost of jigs is higher. They are the special tools particularly used in drilling, reaming, tapping and boring Operations. Jigs are not fixed to the machine table until a big operation is not required to perform. What are Fixtures? Fixtures are the work holding device which holds, supports and locate the workpiece but not guides the cutting tool to perform a specific operation. In other words the fixtures are only the work holding device that holds, supports and locate the workpiece in desried position to perform any operation. The main purpose of the fixtures is to hold and locate the workpiece during any machining operation in the industries. And to provide repeatability, accuracy and interchangeability in the manufacturing of products. It is used in multidimensional machining i.e. milling, grinding, turning etc. Fixtures are found to be heavy in weight and have less complex designing. In fixtures, gauge blocks may be provided for effective handling and the cost of fixtures is not so high. Fixtures are specific tools used particularly in milling machine, shapers and slotting machine. Fixtures are fixed to the machine table. Difference Between Jigs and Fixtures in Tabular Form: The various difference between jigs and fixtures in the tabular form are given below: S.no Jigs Fixtures 1. It is a work holding device that holds, supports and locates the workpiece and guides the cutting tool for a specific operation. It is a work holding device that holds, supports and locates the workpiece for a specific operation but does not guide the cutting tool 2. jigs are used in unidimensional machining i.e. drilling,reaming, tapping, etc fixtures are used in multidimensional machining i.e. milling,turning,grinding,etc . 3. Jigs are light in weight. Fixtures are rigid and bulky. 4. Gauge blocks are not necessary. Gauge blocks may be provided for effective handling. 5. The jigs are special tools particularly used in drilling, reaming, tapping and boring operation. Fixtures are specific tools used particularly in milling machine, shapers and slotting machine 6. Usually it is not fixed to the machine table. It is fixed to the machine table. 7. Its cost is more. Its cost is less as compared with the jig. 8. Their designing is complex. Their designing is less complex. Summary of Difference Between Jigs and Fixtures Jigs are the device which is used to holds, supports and locate the workpiece and it guides the cutting tool for a specific operation. Fixtures are the device which is used to hold, support and locate the workpiece and they don’t guide the cutting tool. Jigs are used in unidimensional machining whereas fixtures are used in multidimensional machining. In jigs, gauge blocks is not necessary. In fixtures gauge blocks may provided for effective handling. Jigs are light in weight as compared with the fixtures. The cost of jigs is higher when it is compared with the fixtures. The jigs designing is complex where as fixtures designing is less complex. Jigs are not fitted to the machine table but fixtures are fitted.
  11. 1 point
    I think it's about their main geometry, Shivank. I mean lapping is plane, honing is cylindrical. But these are old memories (about 1997-98).
  12. 1 point
    The purpose for a governor on at CI engine is the same as the purpose for a governor on any machine: to maintain constant speed under varying load conditions. DrD
  13. 1 point
    The fundamental law of gearing states that for a constant velocity ratio, the pitch point must be stationary. DrD
  14. 1 point
    Tolerances are allowed so it aid in interchangeability of the product during use, assembly and when subjected to different conditions. It is most derived from the purpose of which the product is to be used for. Environment i.e temperature , application depending on speeds, assembly so it can suit global use.
  15. 1 point

    Version 1.0.0


    It will give you a brief idea about the cylinder arrangements in an engine
  16. 1 point
    What is mohr's circle used for ? Explain its application. 1. You can answer this question 2. You can like the best answer 3. You can share the question...
  17. 1 point

    What is 'CC' of a bike? How does it matter?

    This is one important point missing in the two previous answers. The "cc rating" of an engine is a volume measure, as previously stated, but it is not the actual cylinder volume. Rather, it is the swept volume of the cylinder, also called the "displacement" of the cylinder. The actual cylinder volume is always somewhat greater than this value because the piston at TDC does not leave zero cylinder volume. The small volume remaining at TDC is called the "clearance volume," the volume available for the early stage of combustion. DrD
  18. 1 point
    With "Gear Hobbing", both Cutter and Gear are in action or rotation, With "Gear Shaping" only the Cutter is in action or rotation ,, tool feed remains the same for both !!
  19. 1 point
    Though your question's somewhat vague, intentionally increasing clearance (boring) the cylinders is to increase cylindrical volume, to increase compression ratio and improve power. Unintentionally increased clearance (from wear) will decrease compression ratio due to creating a larger volumetric area which decreases amount of compression per amount of gas allowed in to the cylinder. Also allows for leakage.
  20. 1 point
    Ghajini Mohamad explained well. Torsional rigidity is the force limit before a solid deforms or fatigues. In other words, a solid's resistance (elasticity) to radial twisting (torquing). Lateral rigidity is the force limit forces generated along its axis(es). With a rectangular solid, it can bend (curve) or deform the solid until its sides which are affected by the opposing forces becomes non parallel.
  21. 1 point
    Hobbing is the process of roughly, quickly cutting teeth in a gear. A hob is a rotary device which, used for worm, spur or helical gears. Is often used for a known gear type or mass production where cost efficiency is paramount. Shaping is when a power tool (such as a bridge port or boring mill) cuts individual teeth. For an unusual type of gear.
  22. 1 point
    Drill sleeves are often used with drill bits which have tapered shanks. The tapered shank inserts into a sleeve of matching taper in the drill chuck.
  23. 1 point
    Well, to answer this in simple terms.. Rigidity is the maximum resistance an object can offer before it deforms, in other words, it is the minimum force required to deform an object. Torsional Rigidity : The minimum force required to deform an object by twisting through a unit dimension..(in this case, for twisting the dimension is in angle of twist) Lateral Rigidity : Again, the same logic.. The minimum force required to deform an object by bending along the lateral axis through a unit dimension..in this case, the dimension of bending is normally in mm or other length measure scale.. (if the bending load is applied on the longitudinal axis, then the object will not bend, instead the load will act like a compression load), Both Torsional and Lateral Rigidity are considered for the design of shafts with rotating components like gears/pulleys, etc.
  24. 1 point
    There is no single answer that applies in all situations. At one point in my career, I was involved in pipeline vibrations work for natural gas transmission pipelines. These pipelines use very large reciprocating compressors to move the natural gas several thousand miles. The discharge from a reciprocating compressor has highly variable pressure as the valves open, the flow moves through the valve, and then the valve closes for the next stroke. These pressure variations, referred to as "pipeline acoustics," cause the entire assembly to shake and can do much fatigue damage to the piping. Fatigue in turn leads to cracks and cracks allow leaks. This is one strong reason for pipeline leaks. DrD
  25. 1 point
    A good question. However, to start off the photo is of a centre lathe and not a Capstan lathe. However, back to the difference... a Capstan lathe has the base of the turret mainly permanently fastened to the bed of the machine and the turret has an independent slide. On a turret lathe Both the turret and the turret base move along the bed of the machine. Turret lathes are generally used for larger work whereas capstans are mainly used for bar work.
  26. 1 point
    CFD is a computer based flow simulations, where the aim is to solve the Navier-Stokes equations. The equations to be studied are a consequence of the laws of conservation of mass, momentum and energy. FEM is a computer based solid, heat and flow simulations, where the aim is to integrate equations. The equations to be studied are mechanical partial differential equations which are approximated by a set of algebraic equations or a set of ordinary differential equations.
  27. 1 point
    Kesava Moorthi

    Explain why washers are used?

    To protect the bolt hole, spread the load & forces evenly, as a spacer, protect the nut from crevice & galvanic corrosion.
  28. 1 point
    in heat transfer, we study about process of transferring heat from one body to an other body like conduction ,convection & radiation but in thermodynamics we study about the effects of transferring heat on body like internal energy , entropy, enthalpy
  29. 1 point
    thermodynamics is defines the relation between heat and temperature with energy and work in a system. its also a large scale analysis. also its is not counting the heat transfer rate heat transfer determines the heat transfer from a system to the surroundings though the conduction, convection and radiation modes of heat transfer. this is also helps to identify and reduce energy lose through heat energy
  30. 1 point
    damper used to control vibration with the help of resistance and this vibration energy release in the form of heat energy isolator used to support damping and control wave vibration due to shock loads by absorbing the vibration energy.
  31. 1 point

    What is EDM & When do you need it.

    What is EDM? A Brief History The acronym EDM is derived from Electrical Discharge Machining. The EDM process we know today started with the observations of Joseph Preistly in 1770. He noticed that electrical discharges had removed material from the electrodes in his experiments. This is also known as electro-discharge erosion. In the 1940's two Soviet researchers, the Lazarenkos', developed a machining process that formed the foundation for modern EDM. Electric Discharge MachiningThe basic EDM process is really quite simple. An electrical spark is created between an electrode and a workpiece. The spark is visible evidence of the flow of electricity. This electric spark produces intense heat with temperatures reaching 8000 to 12000 degrees Celsius, melting almost anything. The spark is very carefully controlled and localized so that it only affects the surface of the material. The EDM process usually does not affect the heat treat below the surface. With wire EDM the spark always takes place in the dielectric of deionized water. The conductivity of the water is carefully controlled making an excellent environment for the EDM process. The water acts as a coolant and flushes away the eroded metal particles. Wire Cutting EDM wire cutting uses a metallic wire to cut a programmed contour in a workpiece. Extrusion dies and blanking punches are very often machined by wire cutting. Cutting is always through the entire workpiece. To start machining it is first necessary to drill a hole in the workpiece or start from the edge. On the machining area, each discharge creates a crater in the workpiece and an impact on the tool. The wire can be inclined, thus making it possible to make parts with taper or with different profiles at the top and bottom. There is never any mechanical contact between the electrode and workpiece (see above). The wire is usually made of brass or stratified copper, and is between 0.1 and 0.3 mm diameter. Depending on the accuracy and surface finish needed, a part will either be one cut or it will be roughed and skimmed. On a one cut the wire ideally passes through a solid part and drops a slug or scrap piece when it is done. This will give adequate accuracy for some jobs, but most of the time, skimming is necessary. A skim cut is where the wire is passed back over the roughed surface again with a lower power setting and low pressure flush. There can be from one to nine skim passes depending on the accuracy and surface finish required. Usually there are just two skim passes. A skim pass can remove as much as 0.002" of material or a as little as 0.0001". During roughing ( i.e. the first cut) the water is forced into the cut at high pressure in order to provide plenty of cooling and eliminate eroded particles as fast as possible. During skimming (accuracy / finish cuts) the water is gently flowed over the burn so as not to deflect the wire.
  32. 1 point
    Good comment, Arvind. In the USA, reciprocating compressors are used in a vast network of pipelines to transport natural gas from the sources in the southwest to the more heavily populated northeast. It is not possible to simply raise the gas to high pressure at the source and expect it to travel several thousand miles through the pipe without further pumping. Consequently, natural gas pipe lines have compressor stations every 10 to 15 miles, and the entire volume of gas comes out of the ground and passes through a recip compressor at each compressor station. Usually the compressors are powered by natural gas, taken from the pipeline flow, and burned in a diesel engine converted for spark ignition. You are certainly correct about the need for surge chambers and proper consideration of the pulsations. The pulsation damping chambers must be properly designed -- not just any old tank -- so that pulsating pressure does not shake the piping and cause fatigue failures. To the best of my knowledge, I don't think centrifugal machines are ever used in this service.
  33. 1 point
    Both hydraulic and pneumatic systems leak, but the consequences of the leak is almost always worse with hydraulics. This is a major factor in favor of pneumatics in places such as crew spaces on shipboard. On the other side of the coin, a major pneumatic leak makes a worse noise than a substantial hydraulic leak, so that is also a consideration.
  34. 1 point
    ABS- it allows the brakes to be applied while maintaining a tractive contact with the road. it does not allow the wheels to be stopped a once. if it was stopped at once due to inertia(because of the speed with which it comes), the vehicles skids. it is more prominent in low friction surfaces like on ice, wet road etc. In ABS the wheels are not stopped at once. It grips the disc mounted on the wheel. the disc is pressed and released with a gap of nanoseconds. thus the driver do not actually feel it. It increases the braking distance. EBD- It is an electronic device that is mounted on the vehicle, that actually varies the amount of braking force on each wheel depending upon the road conditions. if one wheel is on a high friction surface less braking force is required on that wheel. thus by sensing the road conditions the amount of brake force is varied.
  35. 1 point
    Its a valve. It is located in the cooling circuit, between the engine and the radiator. If it opens it allows flow of water, assisted by a water pump, to take place from the block to the radiator in order to allow the block to "give up" excessive heat. It is a self regulating device and it is calibrated to open at a particular temperature - usually about 95 degrees C. It has a hysteresis also, that is a gap between the open and close temperature due to mechanical friction within the device itself and therefore after cooling has taken place it may not close again until the temperature drops to 90 degrees C - a hysteresis of 5 degrees C. So in this example, when the engine gets to temperature, it should maintain an operating temperature of between 90-95 degrees C. Why is this important? It is critical for a couple of reasons, firstly the many machined limits and fits of critical moving parts are designed with the prescribed operating temperature in mind. Secondly, and maybe more critically, the lubricating oil viscosity is too thick at low temps and too thin at higher temps. Oil breaks down rapidly when subject to too high a temp and closely machined mechanical parts experience boundary lubrication - that is metal to metal contact. Probably the best way to screw up your engine is to allow it to overheat! Irlanski
  36. 1 point
    When you say "nomenclature," I presume you are speaking of the specifictions (dimensions, materials). Based on that understanding, I think the answer is, with only that, you cannot evaluate the torque. You need to know a good bit about the combustion process that takes place, and that requires a knowledge of the fuels, the temperatures, and a lot of thermodynamics. If you have a credible P-V diagram for the engine at the operating point of interest, then a dynamic analysis of the engine can provide the output torque, based on that P-V diagram. It is not simple, and it requires quite a lot of calculation, but it can be done with some accuracy. But, and this is a big but, it will only be as good as the P-V data you start with.
  37. 1 point
    Drafting is essentially drawing a picture, whether in 2D or 3D, and providing dimensions and notes. A drafter may do some "catalog engineering," (selecting parts such as bearings, seals, etc. from a catalog), but drafters do not use any truly advanced mathematics (as a rule). Design, on the other hand, may be making a sketch, but it is also providing the analysis to justify the selection of component sizes (based on stress, deflection, fatigue, etc.), determination of system dynamic response and assuring that criteria are met, etc. Design goes much, much further than drafting.
  38. 1 point
    primary objective of inter-cooling is to obtain higher pressure at lower temperature......eventually it reduced amount of work to be done on gases.....which results in higher efficiency
  39. 1 point
    Clutch can be engaged or disengaged at the will of operator but coupling is fixed type in this regard.
  40. 1 point
    A foot valve is a check valve.It is installed at suction line's bottom in a centrifugal pump.
  41. 1 point
    Akanksha Mahra The jack can be raised and lowered with a metal bar that is inserted into the jack. The operator turns the bar with his hands in a clockwise direction. This turns the screw inside the jack and makes it go up. The screw lifts the small metal cylinder that are above it. As the jack goes up, whatever is placed above it will raise as well. To lower the jack the bar is turned in the opposite direction. https://www.facebook.com/photo.php?fbid=1015237968575 3183&set=a.389510768182.168169.260450433182&type=1
  42. 1 point
    Think of Design for Assembly as prototyping. You make a design that works, that can be built in a shop. Design for manufacturing involves shifting part placements, part types, etc. so as to make sure it can be easily manufactured, repeatably and cheaply, with many part placements done in a simple manufacturing style. Take an engine for example. A prototype (design for assembly) may require machining by machinists, and assembly by the engineers/machinists. Fasteners, connectors, etc wherever it makes sense in the design. But for design for manufacturing, you'd design it such that as many fasteners as possible are on the same side at the same angle, so they can be easily placed all at once by a machine. Something that can't happen if they are all over the place. So you are taking into consideration how the piece will be manufactured on a large scale instead of just how to make the design work.
  43. 1 point
    clutch is a device use to engage or disengage the shaft of the gearbox to the shaft of wheel, while coupling is used to joint two shaft permanantely or temporary,...
  44. 1 point



    Shear force and Bending moment diagrams 2 Presentations Strength of materials / Mechanics of solid
  45. 1 point
    Dial Gauge is a measuring instrument used to measure small distances Slip Gauge is a piece of hardened steel which is machined in a standard size.This is used to accurately make gaps
  46. 1 point
    When we manufacture any product, usually we manufacture it by casting or forging process. To get a proper surface finish of that product we need a proper machining. At the time of maching a certain amount of material usually removed from the surface of the core product. For this reason a tolerance is needed over the designed dimension to maintain the actual dimension. Beside this reason, tolerances also kept to maintain the needed dimension after thermal expansion or contraction at the time of solidification during casting process.
  47. 1 point
    Type Of Ignition: SI CI Cycle Of Operation Diesel Otto Dual Fuel Used Petrol Diesel Gas Electric Cooling method Air Water Oil Stokes 2 stoke 4 stroke No.Of Cylinders 1 2 3 4 6 8 12 16 Valve location L-head I-head F-Head T-head (Usually said as LIFT heads) Cylinder Nature V-type vertical opposed Radial Speed Low Medium High Lubrication method Wet sump Dry sump That's all folks, if found other than this, please leave a comment. I remember a type based on application, but it is not technical. So i left that type.
  48. 1 point

    For what Fanning diagram is used for?

    Arvind Laad Head Engineering at Creative Ashtech Power Projects Private Limited This diagram is used to find the nature of flow of viscous slurry- whether it is laminar or turbulent. It is also used to derive the coefficient of friction in such cases in order to work out the pressure drop in these pipelines & thus fix the slurry pump parameters.
  49. 1 point
    Screw Jack :- Is a mechanical device used in applications where linear motion is required. Lifting of any load, pushing or pulling of mechanical equipment, adjusting of tight clearances of mechanical parts can be done by screw jacks. Mechanical capacity of screw jacks is between 5kN and 2000kN. Jack screws can be used as linear motors, linear actuators, or mechanical lifts depending on type of motio
  50. 1 point
    major differences are PELTON WHEEL- high working head, tangential water flow, low specific speed, low discharge and impulse type of turbine KAPLAN TURBINE- low working head, axial water flow, high specific speed, very high discharge and reaction type of turbine