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Sinks numbers needed

Sindlady, heating surface area needs are not direcdy proportional to the number of effects used. For some types of evaporator, heat-transfer coefficients decline with temperature difference as effects are added the surface needed in each effect increases. On the other hand, heat-transfer coefficients increase with temperature level. In a single effect, all evaporation takes place at a temperature near that of the heat sink, whereas in a double effect half the evaporation takes place at this temperature and the other half at a higher temperature, thereby improving the mean evaporating temperature. Other factors to be considered are the BPR, which is additive in a multiple-effect evaporator and therefore reduces the net AT available for heat transfer as the number of effects is increased, and the reduced demand for steam and cooling water and hence the capital costs of these auxiUaries as the number of effects is increased. [Pg.476]

Since icosahedral carboranes are generally viewed as 3D energy sinks as well as polymer building blocks, the thermal and radiation stability that these units impart on the base rubbery material needs to be explored. While the thermal stability of these materials has been studied and reported by a number of workers, there is little reported work on the stability of these materials to ionizing radiation. A brief account of our work within this area is detailed below. [Pg.110]

The second item that needs to be fixed is the number of species and the reactions, including the stoichiometric coefficients and also the kinetics of the processes. In this context, in electrochemical oxidation processes it is important to discern between two types of anodes those that behaves only as electrons sinks (named nonactive) and those that suffer changes during the electrochemical oxidation which influence on the treatment (named active electrodes). In both cases, the main processes related to removal of the pollutant that involves irreversible oxidative routes. Consequently, the reductive processes are less important and it can be presumed that in the cathodic zone only hydrogen evolution occurs. Nevertheless, if some organic compound can be reduced at the cathode, the mass-transfer and the reduction processes must be included in the model scheme. [Pg.115]

Pinch analysis is a thermodynamically based method for the design of heat and power systems. The method of pinch analysis groups the heat sources and sinks of the process streams into temperature intervals, where it is possible to transfer heat in each interval from heat sources to heat sinks [3], The grand composite curve can be used to provide an interface between the distillation column and the utility system. If a number of different utilities are available, the grand composite curve can be used to determine the relative amount of each utility needed. [Pg.170]

SFB 624 in Bonn proposed a definition for template-assisted reactions [265] which states that a template steers a reaction through spatial pre-organization of the reactants via a suitably defined pattern of non-covalent, covalent, or coordinative-reversible bonds. It acts as an entropic sink such that thermochemical criteria can be used to characterize the template-mediated process. Template-mediated reactions may revolve several times but high turn over numbers are not necessarily required. Also, the template does not necessarily need to be recovered once the reaction took place. In this work, we elaborate on this non-formal description, which aims to embrace as many chemical processes involving templates and host-guest interactions as possible. Our aim is to arrive at a more formal basis utilizing well-established thermochemical concepts. The classical thermochemical approach of physical chemistry to chemical reactions may provide an option to define transferable concepts for the plethora of template-assisted processes. [Pg.457]

The theories describing adsorption and desorption phenomena are well established. Unfortunately, only limited studies have been performed to develop parameters applicable to indoor environments. Small chamber data are usually insufficient to describe the sink behavior (especially desorption rates) in full-scale situations, and only a very small number of test house studies have been conducted to develop sink parameters. Sink effects can have a major impact on the long-term concentrations of pollutants in indoor environments and on the exposure of human occupants to indoor air pollutants. While lAQ models can be used to estimate the effect of sinks on exposures, such estimates can be improved when better data are available on sinks. Additional research is needed to fully understand and describe the behavior of sinks in indoor environments. [Pg.85]


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