Specific Heat of a Substance Q = m . C . Δt Q = heat transfer in kJ, m = mass in kg C = specific heat Δt = $t_2 – t_1$ = temperature change in Kelvin (final temperature – initial temperature) Unit: kJ/kg K Enthalpy H = U + p . V H = specific enthalpy U = specific internal energy of gas First Law of Thermodynamics (Joule’s Experiment) First law as applied to closed system ∮d’ Q = ∮d’ w First law as applied to closed system processes Q = W + ΔU Coefficient of Performance (C.O.P) $W ...
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Resistance Welding (Electric Resistance Welding) $H = I^2 RT$ Some terms, H = heat generated in joules, I = current in amperes, R = resistance at the contacting area between two metal parts in ohms, t = time of current flow in seconds
Belt Drives Some terms: Consider a belt drive, d = diameter of the driving pulley, mm D = diameter of the driven pulley, mm n = speed of the driving pulley, r.p.m. N = speed of the driven pulley, r.p.m. t = thickness of the belt, mm V = linear speed of the belt, mm/s i = speed ratio or velocity ratio Linear speed of the belt, $V = {πdn}/{60}$ or $V = {πDN}/{60}$ $n/N = D/d$ Speed ratio, or velocity ratio, $i = {\text"Speed of driving pulley"}/{\text"Speed of driven pulley"}$ $i = n/N = D/d$ if thickness of belt ...
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