Type of PCM

The three types of PCM are organic, inorganic, and eutectic PCM, as is described in Table 62.1. 

This type of PCM is divided in paraffin compounds and nonparaffin compounds (fatty acids mostly). Principal advantages of organic PCM are the chemical and thermal stability, they are noncorrosive, they are recyclable, and they have no subcooling. On the other hand, the disadvantages are their flammability, low thermal conductivity (k), and low phase change enthalpy. 

The thermal capadty (latent heat) is, of course, a function of the type of PCM (see Table 7.4) for some medium chain-length alkanes (see also Table 7.2). The total thermal capadty of the PCM in certain products depends on the spedfic thermal capadty and the quantity used. 

In summary, the thermal properties of the electrospun form-stable PCM/polymer composite fibers can be affected dramatically according to different types of PCMs [14, 31, 38, 43, 48] and various PCM/polymer mass ratios or PCM contents [14, 33, 37-39, 41, 43, 48, 49]. The former factor is in charge of the intrinsic thermal properties of the novel thermal-storage materials, because it fixes the phase transition temperatures and limits the maximum value of the latent heats of the composite fibers. The latter one plays a key role in the latent heats of the form-stable PCM/polymer composite fibers but has less effect on their phase transition temperatures. All those novel composite fibers showed good thermal stability and reliability no matter what electrospinning methods were applied. 

However, the chief purpose of introduction of fillers into PCM is to make possible the modification of polymers and thereby create materials with a prescribed set of physico-mechanical properties, and, obviously, the properties of filled materials may be controlled by, for example, varying the type of the base polymer (the matrix ) and filler, its particle size distribution and shape. It may not require a large quantity of filler [7]. Thanks to considerable advances in PCM research, their use in a broad range of industries — machine building, construction, aerospace technology, etc. — has become extensive [8 — 11]. 

Table 7 compares free energies of hydration125 produced by the two types of solvent models that have been presented discrete molecular and continuum. The discrete molecular involved classical force field molecular dynamics (MD) and a free energy perturbation (FEP) technique whereby the solute molecule is annihilated to dummy atoms, so that absolute AGhydration are obtained the continuum were SCRF/PCM calculations, with Claverie-Pierotti Gcavilatlon and Floris-Tomasi Gvdw. The... 

The second chapter presents extensions and generalizations of continuum solvation models (mostly of PCM type but not exclusively) to the calculation of molecular properties (both dynamic and static) and spectroscopic features of molecular solutes in different environments of increasing complexity. 

Above, we have rapidly presented a few types of applications of continuum solvent models to the study of phenomena involving molecular excited states. Others could be mentioned as the case of chromophore inserted into a polymeric matrix or in organic crystals and the case of liquid systems experiencing a large external pressure. These are cases for which the computational version of PCM has been elaborated and tested [1,11,12], but many other phenomena have not been considered yet. There are big expectations for the future, and we are confident that within few years, the collective efforts of the laboratories working on these... 

When data on airborne levels are available only in terms of mass/volume (e.g., mg/m ), it is not possible to accurately convert these to units of PCM fibers/mL, because the ratio between mass and fiber number depends on fiber type and size distribution and because of the measuring technique employed. For the purposes of making rough calculations when a more accurate conversion factor is not available, it has been assumed that a concentration of 1 mg/m in air is equal to 33 PCM fimL (EPA 1986a). 

Type of catalyst Operating condition PCM emission Rrference... 

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