The initial ultimate bod after mixing of the bergelmir river is 12.0 mg · l−1. the do in the bergelmir river after the wastewater and river have mixed is at saturation. the river temperature is 10◦ c. at 10◦ c, the deoxygenation rate constant (kd) is 0.30 day−1 , and the reaeration rate constant (kr) is 0.40 day−1 . determine the critical point (tc) and the critical do. tc = 2.88 days. critical do = 7.53 mg · l−1

If the thermal strain developed in polyimide film during deposition is given as 0.0044. assume room temperature is kept at 17.3 c, and thermal coefficient of expansion for the film and the substrate are 54 x 10^-6c^-1 and 3.3 x 10^-6c^-1respectively. calculate the deposition temperature.

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

Thermal stresses are developed in a metal when its a) initial temperature is changed b) final temperature is changed c) density is changed d) thermal deformation is prevented e) expansion is prevented f) contraction is prevented