Engineering Answers

Consider an ordinary shower where hot water at 60 oC is mixed with cold water at 10 oC. If it is desired that a steady stream of water at 45 oC be supplied, determine the ratio of the mass flow rates of the hot to cold water. Assume the heat losses from the mixing chamber to be negligible and the mixing to take place at a pressure of 150 kPa.

A Certain rocket, initially at rest, is shot straight up with an acceleration of 6t m/s2 during the first seconds after blast-off, after which the engine cuts out and is subject

only to gravitational acceleration. How high will the rocket go? Use g=10 m/s2

A vertical face ogee 1.5m is operating at a design head of 3m. Calculate the depth of flow immediately dowmstream from the weir

A solid cylinder, 0 ≤ r ≤ b, is initially at zero temperature. For times t > 0, the boundary condition at r = b is subjected to a time-dependent prescribed temperature f (t) defined by

First plot (i.e., sketch) the boundary condition f (t). Using Duhamel’s theorem, develop an expression for the temperature distribution T(r,t) in the cylinder for times (i) τ₁ 3.

Steam at 3.5 MPa and with a 75.38C superheat rejects 1973.36 kJ per kg of steam heat at a

constant pressure, determine

a. Properties of steam at state 1

b. Properties of steam at state 2

c. Final Temperature

d. Change in specific entropy

A piston-cylinder device initially contains 10L of liquid water at 25C and at atmospheric

pressure of 101.325 kPa. Heat is added at constant pressure until the entire liquid is

vaporized. (a) what is the mass of water (b) final temperature (c) amount of heat absorbed

by the water.

A refrigerator is maintained at 4˚C by removing heat from it at a rate of 8 kW. If the required power input to the refrigerator is 2.5 KW, determine (a) the COPR and (b) the rate of heat rejection to the room that houses the refrigerator

a) Define Maintainability and availability and compare it with reliability.

b) What is inspection and repair availability model? Explain a case for it.  

Perform a qualitative analysis on the following fault tree by expressing the top event in terms of non-reductant basic events using Boolean algebra. If the probability of each basic event is 0.005 and events are independent, what is the probability of the top event?

Find out the reliability using markov analysis for load sharing units?

(b) A manufacturing company operates two production lines when both lines are operating, the production rate on each line is 500 units per hour. At this production rate the failure rate of line 1 is 3 failures per 8-hr day (CFR) and the failure rate of line 2 is 2 failures per 8-hr day. When one line fails, the production rate of the second line must be increased in order to make production quotas. At the increased rate of 800 units per hour, the failure rate of line 1 is 6 per 8 hr day and the failure rate of line is 3 per 8-hr day. Find the reliability and the MTTF and the reliability of the production system over a 1 hr and over an 8 hr production run.