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This paper reviews the different types of merit functions that have been used in the past in optical thin film calculations. Attention is drawn to the power of merit functions which operate on complicated quantities that require one or more integral expressions for their definition. To prove this point, several thin film problems are solved in which the CIE coordinates, luminous transmittances or reflectances, solar absorptance, and blackbody emittances of a multilayer are specified.

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At the start of the feed step, thermal swing adsorption (TSA) processes generate a thermal pulse. This thermal pulse is generated by insufficient cooling of the bed during the regeneration step and bed repressurization following the cooling step. For some integrated processes, such as cryogenic air separation units (ASU), the thermal pulse generated by the TSA PPU (pre-purification unit) may not be acceptable. Three options are outlined to minimize the magnitude of the thermal pulse generated by the adsorbent bed during the feed step before the feed enters the equipment downstream of the adsorption process. A mathematical model to simulate this process and results from computer simulations are presented. Various process options are compared. Experimental data is compared against the model predictions.

Pumping performance investigation of a turbobooster vacuum pump equipped with spiral-grooved rotor and inner housing by the computational fluids dynamics method High throughput pumping of dangerous gases with a multistage roots vacuum pump Claw rotor compressors are used in a wide variety of vacuum pumping applications. However, the published literature on these machines offers little guidance on the physical processes which occur during pump operation, their effect on pump performance, or the influence of design and operating parameters. In the present work, a model based on algebraic and differential equations describing pressure and temperature time dependence for a multistage pump is developed. The equations are based on the laws of conservation of mass and energy and use a lumped-parameter approximation. The model includes volume variation, gas flow between stages, leakage within and between stages, gas mixing, and heat exchange. Expressions for the pumping speed and power consumption are also presented. Predictions based on the model are compared with experimental data.