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  1. 1 point


    " A single valve actuates all the valves." This is a nonsense statement. "Qualitatively governed engine" but you say nothing about what this means. I have never heard of such. Also, I see no mention of overhead valve engines, a very important design type today. DrD
  2. 1 point
    mitesh bairwa

    Types of Hydraulic Turbines

    nice images
  3. 1 point
    The mechanical properties of a material are those properties that involve a reaction to an applied load. The mechanical properties of metals determine the range of usefulness of a material and establish the service life that can be expected. Mechanical properties are also used to help classify and identify material. STRENGTH: The strength of a material is its ability to withstand an applied load without failure or plastic deformation.In machine design yield point or ultimate tensile / shear / compressive strength is used while designing. Stiffness: Stiffness is the rigidity of an object — the extent to which it resists deformation in response to an applied force. The complementary concept is flexibility or pliability: the more flexible an object is, the less stiff it is. Hardness: Hardness is a measure of how resistant solid matter is to various kinds of permanent shape change when a compressive force is applied. Some materials (e.g. metals) are harder than others (e.g. plastics). Elasticity: the ability of an object or material to resume its normal shape after being stretched or compressed. On a stress-strain diagram it is considered to be below proportional limit.But widely this point is taken as the yield point by drawing a line offset by 0.2% parallel to the straight line until it intersects the curve. Plasticity: It describes the deformation of a (solid) material undergoing non-reversible changes of shape in response to applied forces. Brittleness: A material is brittle if, when subjected to stress, it breaks without significant plastic deformation. Brittle materials absorb relatively little energy prior to fracture, even those of high strength.
  4. 1 point
    'less Maintenance' you are wrong dude... Diesel engine have more part than petrol engine....Diesel engine have high pressure fuel line, high pressure fuel pump, fuel filter.
  5. 1 point
    Jayesh Sharma95

    Types of Hydraulic Turbines

    What a nice explanation! Really very nice sir. Thanks a lot.
  6. 1 point
    Akhil Yathirajula

    Types of Hydraulic Turbines

    Supperb its helps 2 understand very easily
  7. 1 point
  8. 1 point
    I messed up diesel kerosene gasoline. In the forming process
  9. 1 point
    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
  10. 1 point
    Jeff Macaskill

    Why parabolic fins are preferred ?

    I believe it is because of the way the heat is dicipated. The center copper core is going to be the hottest. A passive heat exchanger that allows for the coldest air away from the heat source to be drawn in at the outside exchanging heat at the tips of the fins while warming up towards the center of the fins where the core is hottest. The parallel heat transfer works its way down to the center core and then out by the fan. Effective heat transfer because the exchange happens across the entire fin in the process...Also slight s shape creates slight disturbance to work on both sides of fin instead of favoring one side in the process.
  11. 1 point
    Om Prakash

    Difference between pump and compressor

    Pumps can handle both liquids and gases. But Compressor can handle only the gases due the incompressible nature of liquids.................
  12. 1 point

    Difference between pump and compressor

    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
  13. 1 point
    hardness is a mechanical property by virtue of which a material resist scratches or indentation on its surface. toughness is also a mechanical property of a material by virtue of which it absorbs shock loading.