Engineering, 16.11.2020 18:10 lee9724
Consider electron-hole recombination under conditions of strong carrier-pair injection such that the recombination lifetime can be approximated by tau=1/(zeta delta n), delta n is the injection-generated excess carrier concentration and zeta is the recombination parameter of the material. Assume that the source of injection R is set to zero at t = t_0, find an analytic expression for delta n(t), demonstrating that it exhibits power-law rather than exponential behavior.
Answers: 2
Engineering, 04.07.2019 18:10
Afour cylinder four-stroke in-line engine has a stroke of 160mm, connecting rod length of 150mm, a reciprocating mass of 3kg and its firing order is 1-3-4-2. the spacing between cylinders is 100mm. i. show that the engine is in balance with regard to the primary inertia forces and primary 3. a and secondary inertia couples. li determine the out of balance secondary inertia force ii. propose ways of balancing this out of balance force and discuss the challenges that will arise
Answers: 3
Engineering, 04.07.2019 18:20
Derive the correction factor formula for conical nozzle i=-(1+ cosa) and calculate the nozzle angle correction factor for a nozzle whose divergence hal-fangle is 13 (hint: assume that all the mass flow originates at the apex of the cone.
Answers: 3
Engineering, 04.07.2019 19:10
A)-in the process of engineering design, explain the contribution of material selection. b)- explain the procedure of synthesis as is employed in engineering design. c)- is there any relationship between ergonomics and engineering design? explain. d)- safety consideration in engineering design includes human, product and the enviroment . explain how safety will be incorporated into the design?
Answers: 3
Engineering, 04.07.2019 19:20
Acommercial grade cubical freezer, 4 m on a side, has a composite wall consisting of an exterior sheet of 5.0-mm thick plain carbon steel (kst= 60.5 w/m k), an intermediate layer of 100-mm thick polyurethane insulation (kins 0.02 w/m k), and an inner sheet of 5.0- mm thick aluminium alloy (kal polyurethane insulation and both metallic sheets are each characterized by a thermal contact resistance of r 2.5 x 104 m2 k/w. (a) what is the steady-state cooling load that must be maintained by the refrigerator under conditions for which the outer and inner surface temperatures are 25°c and -5°c, respectively? (b) for power saving purpose, which wall material should be increased/reduced in. thickness in order to reduce 50% of the cooling load found in part (a)? redesign the thickness of the proposed material. 177 w/m-k). adhesive interfaces between the q=575.93 w
Answers: 2
Consider electron-hole recombination under conditions of strong carrier-pair injection such that the...
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