The recommended time weighted average air concentration for occupational exposure to water soluble hexavalent chromium (Cr VI) i
s 0.05 mg/m3. This concentration is based on the assumption that the individual is generally healthy and is exposed for 8 hours per day, 5 days per week, 50 weeks per year, over a working lifetime (that is from age 18 to 65 years). Assuming a body weight of 78 kg and inhalation rate of 15.2 m3/d over the working life of the individual, calculate the lifetime (75 years) CDI.
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Complete Question
Air at 40C flows over a 2 m long flat plate with a free stream velocity of 7m/s. Assume the width of the plate (into the paper) is 0.5 m. If the plate is at a co temperature of 100C,find:
The total heat transfer rate from the plate to the air
Answer:
Explanation:
From the question we are told that:
Air Temperature
Length
Velocity
Width
Constant temperature
Generally the equation for Total heat Transfer is mathematically given by
Where
h=Convective heat transfer coefficient
Therefore
Answer:
5.6 mm
Explanation:
Given that:
A cylindrical tank is required to contain a:
Gage Pressure P = 560 kPa
Allowable normal stress = 150 MPa = 150000 Kpa.
The inner diameter of the tank = 3 m
In a closed cylinder there exist both the circumferential stress and the longitudinal stress.
Circumferential stress
Making thickness t the subject; we have
t = 0.0056 m
t = 5.6 mm
For longitudinal stress.
t = 0.0028 mm
t = 2.8 mm
From the above circumferential stress and longitudinal stress; the stress with the higher value will be considered ; which is circumferential stress and it's minimum value with the maximum thickness = 5.6 mm