Structure thermal characteristics

The flow and heat transfer in heated micro-channels are accompanied by a number of thermohydrodynamic processes, such as liquid heating and vaporization, boiling, formation of two-phase mixtures with a very complicated inner structure, etc., which affect significantly the hydrodynamic and thermal characteristics of the cooling systems. 

Metal monoliths show good thermal characteristics. A typical support with herringbone channels made from Fecralloy performed satisfactory in automotive applications [27]. Modeling showed that overall heat transfer was about 2 times higher than for conventional pellets [28,29]. Hence, there is potential for structured catalysts for gas-phase catalytic processes in multitubular reactors. 

Polymer refers to a generic name which is assigned to a vast number of materials of high Molecular weight. These materials are known to exist in numerous forms and numbers because of a very large number and types of atoms present in their molecules. Polymers can be having different chemical structures, physical properties, mechanical behaviour, thermal characteristics, etc., and would be classified on different ways. 

In Fig. 5.5, the flow configuration and velocity and temperature distributions at the time instant of 12.5 s are depicted. Even though the flow is subsonic, due to the high Reynolds number, the flow structure in the region upstream of the solid propellant is minimally affected by the time-dependent boundary shape due to phase change. However, the thermal characteristics near the propellant interface show clear signs of time dependency, indicating that the mass flux of... 

The simplest recording medium is a bilayer structure. It is constructed by first evaporating a highly reflective aluminum layer onto a suitable disk substrate. Next, a thin film (15-50 nm thick) of a metal, such as tellurium, is vacuum deposited on top of the aluminum layer. The laser power required to form the mark is dependent on the thermal characteristics of the metal film. Tellurium, for example, has a low thermal diffusivity and a melting point of 452 °C which make it an attractive recording material. The thermal diffusivity of the substrate material should also be as low as possible, since a significant fraction of the heat generated in the metal layer can be conducted to the substrate. For this reason, low cost polymer substrates such as poly (methylmethacrylate) or poly (vinyl chloride) are ideal. 

V.V. Korshak, Khimicheskoe Stroenie i Temperaturnye Kharakteristiki Polymerov [Chemical Structure and Thermal Characteristics of Polymers], Nauka, Moscow, Russia, 1970. [in Russian]... 

The crystalline structure of modified zeolites determine a number of properties which are specific and favorable for catalytic reactions. The complete or partial loss of crystalline structure during catalytic reactions or regeneration is in most cases accompanied by decreased catalytic activity. Thermal stability or structural stability characteristics are therefore suitable for evaluating such catalysts or supported catalysts. 

Korshak W, "The Chemical Structure and Thermal Characteristics of Polymers", (Translation), Israel Program for Scientific Translations, Jerusalem, 1971. 

The thermal characteristics exhibited by the series 11 [18] and 14 [20] proved that interesting liquid crystal properties can be obtained with symmetrically 1,T-disubstituted ferrocene derivatives. The structure of the organic unit, which is combined with the ferrocenyl moiety, must be carefully chosen. 

Analytical pyrolysis has a number of characteristics that can make it a very powerful tool in the study of polymers and composite materials. The technique usually requires little sample and can be set with very low limits of detection for a number of analytes. For Py-GC/MS the identification capability of volatile pyrolysate components is exceptionally good. A range of information can be obtained using this technique, including results for polymer identification, polymer structure, thermal properties of polymers, identification of polymer additives, and for the generation of potentially harmful small molecules from polymer decomposition. In most cases of analysis of a polymer or composite material, the technique does not require any sample preparation, not even solubilization of the sample, which may be a difficult task for the type of materials analyzed. The analysis can be easily automated and does not require expensive instrumentation (beyond the cost of the instrument used for pyrolysate analysis). 

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