Subject thermal processing

The obtained graph is the basis for evaluating the stress while applying the probe to controlled elements made of the same material and subjected to identical thermal processing as the reference sample... 

Control of sonochemical reactions is subject to the same limitation that any thermal process has the Boltzmann energy distribution means that the energy per individual molecule wiU vary widely. One does have easy control, however, over the energetics of cavitation through the parameters of acoustic intensity, temperature, ambient gas, and solvent choice. The thermal conductivity of the ambient gas (eg, a variable He/Ar atmosphere) and the overaU solvent vapor pressure provide easy methods for the experimental control of the peak temperatures generated during the cavitational coUapse. 

The process by which porous sintered plaques are filled with active material is called impregnation. The plaques are submerged in an aqueous solution, which is sometimes a hot melt in a compound s own water of hydration, consisting of a suitable nickel or cadmium salt and subjected to a chemical, electrochemical, or thermal process to precipitate nickel hydroxide or cadmium hydroxide. The electrochemical (46) and general (47) methods of impregnating nickel plaques have been reviewed. 

Several allotropic forms of phosphorus are known, the most common of which are the white, red, and black forms. Heating the white form at 400 °C for several hours produces red phosphorus, which is known to include several forms. A red form that is amorphous can be prepared by subjecting white phosphorus to ultraviolet radiation. In the thermal process, several substances (I2, S8, and Na) are known to catalyze the conversion of phosphorus to other forms. Black phosphorus consists of four identifiable forms that result when white phosphorus is subjected to heat and pressure. Phosphorus is used in large quantities in the production of phosphoric acid and other chemicals. White phosphorus has been used extensively in making incendiary devices, and red phosphorus is used in making matches. 

The formation of BA is a highly complex thermal process. Varying input materials are subject to high temperature for a short time only, whereby equilibrium conditions may occur only locally in the BA. Chemical and mineralogical analyses of BA coming from 28 MSWI plants in Switzerland with comparable technology show... 

The transformation shown in equation (54) retains many of the features of ordinary photochemical and transition-metal-catalyzed thermal reactions of organic compounds, but displays some unique characteristics as well. In cases where irradiation serves only to accelerate the rate of the expected thermal process, higher chemical yields of product can result, reaction rates are subject to greater control through regulation of light intensity, and thermally sensitive products are isolated more readily since elevated reaction temperatures can be avoided. Alternatively, the function of M may be to facilitate known photochemical reactions of O or perhaps introduce new reaction channels not observed upon irradiation of O alone. A detailed discussion of the mechanisms and synthetic applications of these processes has been presented.177... 

The accurate measurement of chlorophylls has importance for numerous reasons ranging from simple color considerations to medical research. The most practical of these is the assessment of fruit and vegetable color quality, as chlorophylls are known to degrade rapidly when subjected to thermal processing (Schwartz et al., 1981). However, interest has also been sparked by recent literature reports that point to the possible health benefits associated with chlorophyll consumption (Hartig and Bailey, 1998). 

From an analytical perspective, the single most important physicochemical characteristic of riboflavin is its photosensitivity (80-82). Exposure of this vitamin to ultraviolet and visible light results in irreversible photoreduction to lumiflavin and lumichrome and loss of vitamin activity. In addition, the coenzymes are subject to hydrolysis by endogenous phosphatases that are present in a number of foods. Since these enzymes are generally inactivated by thermal processing, they are a concern only in the analysis of fresh products. 

Until recently, the mechanism of the inhibition of light-induced yellowing was subject to speculation. However, solid state ESR and CIDEP have provided insight into the mode of inhibition by thiols (Wan, J.K.S., et al, J. Wood Chem. Technol., in press). Near-uv irradiation of unbleached and peroxide bleached thermomechanical pulp impregnated with thiols caused a rapid increase of the thiol radicals. The time resolved CIDEP spectrum, however, shows a symmetric broad band characteristic of the polarized phenoxy radical. This result suggests that thiols quench triplet generated phenoxy radicals in a secondary thermal process. 

Oxidation modifications such as carbonylation, thiol oxidation, and aromatic hydroxylation, and Maillard glycation (the reaction of sugars with amino acid side chains) are the protein modifications most frequently reported in foodstuffs that have been subjected to thermal processing. However, condensations and eliminations of side chains or peptide backbone breakdown have also been described (95). 

Aromas generated by thermal processes are the subject of this book. 

Subject to satisfactory solution to the questions of engineering and related economies, the manufacturing operations in general today (not only thermal processing) may be controlled by means such as ... 

Besides fluid mechanics, thermal processes also include mass transfer processes (e.g. absorption or desorption of a gas in a liquid, extraction between two liquid phases, dissolution of solids in liquids) and/or heat transfer processes (energy uptake, cooling, heating, drying). In the case of thermal separation processes, such as distillation, rectification, extraction, and so on, mass transfer between the respective phases is subject to thermodynamic laws (phase equilibria) which are obviously not scale dependent. Therefore, one should not be surprised if there are no scale-up rules for the pure rectification process, unless the hydrodynamics of the mass transfer in plate and packed columns are under consideration. If a separation operation (e.g. drying of hygroscopic materials, electrophoresis, etc.) involves simultaneous mass and heat transfer, both of which are scale-dependent, the scale-up is particularly difficult because these two processes obey different laws. 

Thermal Stability. The ABS-type polymers containing sufficient DBPF to pass the Underwriter s test were notably less prone to discoloration during processing than unstabilized PVC. On the other hand, they discolored when subjected to processing conditions normally used for conventional ABS polymers. Tribasic lead silicate was as effective as any of the common PVC stabilizers in preventing this discoloration during milling. 

We fractionated CCB by a high vacuum distillation into several distillate fractions and undistlllable residue. The distillate fractions were subjected to a two-stage high temperature thermal process to convert them to aromatic pitches. The composition of the pitches produced was determined by a solvent analysis to define their suitability for synthetic carbon production. 

If an X-wind is responsible for driving bipolar outflows, then there are possibly important implications for the thermal processing of solids and the production of short-lived radioisotopes (Shu et al., 1996, 2001). The basic idea is that some of the solids that spiral inward and approach the boundary layer between the solar nebula and the protosun will be lifted upward by the same magnetically driven wind that powers bipolar outflows. While close to the protosun, these solids will be subject to heating by the solar radiation... 

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