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  3. Refrigeration is a part of Air Conditioning. Air Conditioning can be divided into Refrigeration, Heating, Addition/Removal of Moisture, Air Purity Control and Air Distribution Control.The basic difference is that the Air Conditioner controls the humidity along with temperature while a Refrigerator controls the temperature.
  4. diesel engine uses fuel injector rather than spark plug.the fuel is burn automatically itself due to high temparature of air and compression of require low ignition temparature to burn yhe fuel.
  5. There's no need of spark plug in diesel engine it cmpress intake air to high degree temperature in the combustion during compression stroke whereas diesel fuel is spray by injector nozzle during the power stroke in to compressed air and ignited whereby pushing the engine downward, that's why we called diesel engines as self ignition engine.
  6. I can't make a CAD model for you but can help you in any particular problem. So please update your problem with more information. I will surely help you.
  7. "I think the human race made a big mistake at the beginning of the industrial revolution, we leaped for the mechanical things, people need the use of their hands to feel creative." - Andre Norton

  8. There are so many differences in a refrigerator and an air conditioner. Broadly speaking, the major is in there operation a refrigerator only make things cooler while an air conditioner makes air good for us that includes controlling humidity removing dust and also controlling temperature. For more info you can go through this page
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  10. The fact that it offers a high gear ratio is certainly an advantage, but that can also be achieved by other mechanisms. The major reason is that, under most circumstances, the worm drive can not be back driven. This is a major safety consideration for a hoist. DrD
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  12. please my group and I are working on a project that involves a foldable tent this is no ordinary tent but its kind of used frequently here in Ghana for funerals and our task is to make a foldable and portable tent that can resist all kinds of weather conditions image of the tent is attached for clarification
  13. Basic Dynamic Load Rating. The basic dynamic load rating (Cr) of a bearing with rotating inner ring and stationary outer ring is that load of constant direction and magnitude which a sufficiently large sample group of apparently identical bearings can endure for a basic rating life of one million revolutions.
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  16. Darcy–Weisbach equation gives the value of head difference or in case of flow, loss of head in the turbulent flow through pipes due to frictional factors, this equation gives this in terms of all the measurable quantities and is derived from the equation of velocity profile. Head loss hf = ((P1 - P2)/(density x g)). Hence is of much importance in experimental works, dimensional analysis and model analysis of flows.
  17. Quality control refers to maintain quality during production on plant, such as if during production part does not meet the quality standards it will be rejected and further no production will be produced against rejected part but during Quality Assurance we check/inspect the quality requirements of old parts, plants and make sure that it is acceptable or not. For example, 2 or 3 years used part , after 3 years we assure its quality that its still fulfill the quality standard requirements.
  18. difference between square thread and v-thread in terms of strength


  19. hello guys.. I need your help about lathe cutting tools(tool-bit).how do we shape cutting tools? is there a specific degrees to use? to measure? I really need your help guys .

    cutting tools to make:

    -Right cut corner

    -Left cut side

    -square nose

    -right cut side

    -brass cutting

    -left cut

    -Round nose

    -right cut

    -left cut corner

    -thread cutting

  20. The rotation will be in a horizontal plane, and the axis is vertical. Am I right if I say that we want drag force instead of lift force? We want most dragforce in the 1. and 4. quadrant (as shown in the picture), seeing that the turbine rotates counter clockwise. The blades will be connected with bearings to ensure rotation for the blades are possible, so that in 1. and 4. quadrant the blades will be standing vertical to ensure a big surface area, and rotate in the 2. and 3. quadrant so that the dragforces are as small as possible in those quadrants. The power will be generated from a generator above water.
  21. Quality assurance means costumer will get quality products, and quality control means to produce quality product in factory. Quality control leads quality assurance.
  22. Diesel engine is compression ignition engine also fuel is less volatile and ignited by compression no throttle valve rpm range of 4500 rev than petrol of 8500 rpm friction will be less ; heavier crankshaft
  23. spark ignition engines due to exhaust system idle rpm exhaust pipe diameter crank weight turbocharger strokes piston length and diameter of piston aging firing order nature of engine sporty or crusie compression ratio muffler method of injection direct or carburator
  24. Air cooled, liquid cooled, carburated or fuel injected, Direct injection, Air filter design, inlet roar, ohv or ohc, hydraulic valve adjustment, shimmed tapets manual tappet asjustment. How many more reasons for different engine sounds do you want
  25. With regard to materials, you must stay away from most metals, and especially aluminium. They will corrode rapidly in a salt water environment and lose strength accordingly. Think more of polyesters and epoxy materials. Are we to understand that rotation is in a horizontal or vertical plane? Assuming a horizontal plane for the rotation, you will need an airfoil shape, as the turning force is developed by hydrodynamic forces. Where will you generate power, below the water or above? This is a difficult problem, one that I worked on for the US Navy some years ago. You have a lot of hurdles to face to get this to work. DrD
  26. Hi! I am writing a bachelor thesis in mechanical engineering about a prototype of a tidal turbine, the one shown in the pictures.This is just a cheap prototype, and I will come up with a better design (especially for the blades) and materials. It is supposed to be attached on a floating device, so it will be positioned just under the sea surface. I was wondering if anyone had any tips or ideas for the blade design? It is necessary that it rotates either way the tidal current is coming from. Should the blades be curved like a wind turbine blade, or more squared like in wells turbines? And what materials would you suggest to use for the blades, as well as rest of the body? I'm thinking maybe some composite materials for the blade and aluminum for the body? Would be great to get some input, thanks. PS. the wheel is just there so it can rotate now, and the diameter of the whole turbine is about 80 cm.
  27. Can anyone help me with this? I am supposed to find Young's modulus and the tensile strength of this copper sample (the blue figure at the top). I have found the values on other websites, books etc, but I cannot seem to get the calculations right. E = 117 GPa and S_u = 220 MPa. If anyone could guide me through this that'd be greatly appreciated!

    Diagram oblig 3.PNG

  28. What is the Length of the crankshaft????
  29. The flywheel does not store force; it stores kinetic energy. This is the source of energy to keep the crank turning during the compression strokes when the cylinder pressure is retarding crank rotation. Imagine that you start a small, single cylinder engine, such as a lawnmower engine, With the lawnmower blade in place, the engine runs just fine, but in many cases if you remove the blade, the engine will not run at idle speed. Why? Because the blade acts as a part of the flywheel, storing energy for the compression stroke. If you remove the blade, there may not be enough energy stored to complete the compression stroke. DrD
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