The roof of a house consists of a 0.70-ft-thick concrete slab (k = 3 W/m · °C) that is 18 m wide and 23 m long. The emissivity of the outer surface of the roof is 0.92, and the convection heat transfer coefficient on that surface is estimated to be 18 W/m² · °C. The inner surface of the roof is maintained at 295 K. On a clear winter night, the ambient air is reported to be at 282.15 K while the night sky temperature for radiation heat transfer is 260 K. Considering both radiation and convection heat transfer, determine the outer surface temperature and the rate of heat transfer through the roof.
Theory and Design for Mechanical Measurements
Measurement is a term that refers to analyzing a manufactured component regarding the degree of accuracy for dimensions, tolerances, geometric profile, roundness, flatness, smoothness, etc. Measurement always involves comparing the manufactured component or the prototype with a standard specimen whose dimensions and other parameters are assumed to be perfect and do not undergo changes with respect to time.Precisely in mechanical engineering the branch that deals with the application of scientific principles for measurements is known as metrology. The domain of metrology in general deals with various measurements like mechanical, chemical, thermodynamic, physical, and biological measurements. In mechanical engineering, the measurements are limited to mechanical specific such as length, mass, surface profile, flatness, roundness, viscosity, heat transfer, etc.
Basic principles of engineering metrology
Metrology is described as the science of measurement, precision, and accuracy. In other words, it is a method of measurement based on units and predefined standards.
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