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  1. 2 points
    1. It's not oil the best name is brake fluid as it consists a lot of material inside such as (silicone, glycol ether/borate ester, mineral oil) 2. One of the main things for BF, it must have a high boiling point to avoid vaporizing in the lines this is why we need to change the brake fluid from time to time as it has tendency to absorb water which will lower its boiling temperature leading to change part of the fluid into moisture and vapour inside the brake circuits and this will create vapour lock leading to being compressible and once it became compressible the brake foot force will not be transferred to the other brake parts (cylinders,brake pistons, ...) We have many types of BF each has its own dry/wet boiling temperature such as:- DOT3 (dry 205C/401F- wet 140C/284F) DOT4 (dry 230C/446F - wet 150C/311F) DOT5 (dry 260C/500F - wet 180C/365F) *Hygroscopic means (water absorbing)
  2. 1 point

    Mechanical Engineering Quiz 1

    How will the balance reading remain same in that "Bucket-Spring balance" question. Reading should increase perhaps.
  3. 1 point
    Why do we need to change brake oil the after a particular interval?
  4. 1 point
    Thanks for writing here,welcome on https://mechanical-engg.com/ look forward for your active participation.
  5. 1 point
    Concept of heating is just simple with respect to welding. Majorly Pre or post heating in welding is to relieve stresses which are used to developed during welding. Pre heating: Power saving - by pre heating, heat gradient can be reduced and so to control heat generation, low heat input can be given and so process characteristics can be reduced accordingly Reduction in internal residual stresses - the stresses will are already inside the material can reduce the strength of the weld, to avoid that, pre treatment can be used Post heating: Post heating or annealing or normalizing is done mainly to reduce the thermal stresses developed during welding To relieve Hydrogen embrittlement in which Hydrogen has entrapped during welding from moisture or the filler material
  6. 1 point
    Eslam Ahmed

    Why pistons are usually dished at top ?

    To provide more turbulence and swirl. Thus, more homogeneous mixture gonna be obtained. This can lead to more heat transfer as well (as the surface area increases).