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G B Reid MIMechE, SIMarEST

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G B Reid MIMechE, SIMarEST last won the day on September 28 2017

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About G B Reid MIMechE, SIMarEST

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    Benfleet, England
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    Mechanical engineering "generalist", experience in Design (industrial, mechanical, aerospace grade components), Rail, Underground, defence, process flow optimisation, Project Engineering and Mechanical Systems 3D CAD user (various) since 1992. Electrical design installation and verification.

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  1. NAFEMS tends to be the authority on modelling, best practice etc. https://www.nafems.org/
  2. Use the forums to build reputation...network at every opportunity and most importantly - Stay Positive no matter what!
  3. Failing that, it is the area integral over the direction applied squared...ie if x direction its the area integral of the y^2 area and if the y direction its the area integral of the x^2 area...
  4. You already know the power...its 15 Watts...one Watt is one Joule per second....just calculate the time element and "Bob's your uncle"!
  5. experiment, experiment, experiment. The strap wrench is a good first step and would most likely be successful. Alternatives can be thought of if the strap wrench doens't work...a combination of rubber-lined v-blocks in a vice for example...?...but the cost increases dramatically.
  6. Your first step here would not be calculation, but geometry! The geometry (as if designing a cam - huge levels of crossover) would give you the critical detail you need for your calculations. The risk of dead spots is purely on being piston driven, but physically impossible in the same due to the conditions...ie can't reach TDC due to pressures and will not stop at BDC due to lowest resistance at this point. On old vintage cars, they would often backfire when stopped as the pressure at TDC would cause the engine to counter rotate slightly as it stopped due to the residual piston pressure.
  7. Doh! Basic error...I didn't read the question properly... ...The room of course! The room cools quickest as that is the only way to break the equilibrium of the temperatures (Room/plates which are both "heated to the same temperature" allowing a differential on the plates forcing them to cool. This may be a semantic answer, but a relevant one.
  8. Assuming both plates are suspended in free air, the vertical unit will cool significantly faster. The convection of the air as a result of heat emanating from the plate will be significantly greater than the horizontal. Effectively, the convection will increase as the warming air travels up the plate faster as it warms more due to the proximity of the sink allowing cold air to replace from the bottom. On the horizontal plate, the air mass above gets 'in the way' of the convective effects due to the effective horizontal area involved...basically, it has to be pushed out of the way by the less dense, warmer air. On the vertically suspended plate, the horizontal equivalent area involved in the convection is significantly lower resulting in significantly reduced air mass effects to slow the convection..this is further aided by the convected air being continually heated as it rises up the plate drawing more energy from the plate.
  9. Hard Water is water with a large amount of calcium carbonate disolved within. When boiled, htis precipitates out to make an unpleasant - but tasteless - grit...it can flake off in large chunks. Soft water is where there is no limescale disolved...although oither salts may be present. Hard water can be converted to soft water for processing by the addition of sodium chloride (common table/rock salt) ot by distillation (or filterring too for that matter). It can also be easily idetified by its loss of surface tension when soap is added (ie it bubbles if its soft!)
  10. Its a simple moment equation to find the CoG/M (depending on preference)...then just ensure the Cog is within the footprint of the...well...foot. If you carry out the calcs for each extreme and then a couple between these extremes, you will get a footprint of utilisation, which is the area within which the foot must always fall. You need a lot more detail, materials for framework, mass, profile etc. I understand why you may want to provide this additional data, but assistance is somewhat restricted without. Good luck!
  11. Any high torque axial step-down that requires minimal vibration.
  12. I am somewhat tempted to answer by stating "lines on a piece of paper"....but somehow I do not think that is the answer you would be hoping for. Please consider the question that you are actually seeking answer for and I shall try and assist.
  13. I agree with Dr D....but that said, I seem to recall something (in the dim an distant past) about placing the highest Bernouli lift to the front of the wing in order to make the wing more stable by use of a tailplane stabilisor... In typing this I am having some memories return....there is also a MUCH LOWER stall speed (ie the airraft has to go much faster to prevent stall) due to the lack of laminar flow across the top surface and very low angles of attack....basically the bullnose at the front encourages laminar flow as the angle of attack rises, whereas the complete opposite is true of the sharper leading edge...ie turbulent flow is encouraged, resulting in reduced pressure drop (Bernoulli effect) and loss of stability and lift. Theoretically, this could be countered by a greater reliance on Newtonian (Reactive) lift, but that is inherently unstable (Turbulent) and difficult to control anyway, so not an ideal situation!
  14. Your best bet is to start reading up on the "ideal Gas Law" and then on the enthalpy of vapourisation. A combination of the two should then give you a good understanding. To answer your specific question though, yes....there is normally a "pinched pipe" that restricts the flow (yes, normally it is that simple)...on some of the "better engineered" versions it is a (very) small bore pipe.
  15. We know F = ma and the mass of the vehicle, from this we can calculate the force from each set of wheels. from the speed of the vehicle, we can calculate the length of time the force is applied. (ie m/s and then width of hump) From the mass of the road hump and spring force keeping it in place, we can can calculate the acceleration of the hump and the time which it is accelerating and the rate, which can be back calculated to give the required figures. The velocity itself will be dependant on the time the vehicle is in contact (F=ma), the overall mass of the hump/spring effects and the amount of energy harvested (ie the retardation effect of the "generator"). The velocity of the vehicle will reduce the amount of time the Force is applied, so the aceleration would not be as high, but this would be balanced by a significantly greater (square law) newtonian effect pushing the hump downward at the point of wheel impact. I would suggest experimental determination rather than calculation as the suspension effect of the tyre and the suspension itself will skew any calculated results. Sounds very interesting - good luck! Your english in the question is excellent!
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