702,090 research outputs found

    A development of an electrical analogue for thermal processing : a thesis presented in partial fulfillment of the requirements for the degree Master of Technology in Biochemistry at Massey University

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    A. THERMAL PROCESSING IN GENERAL Thermal processing implies application of thermal energy at suitable thermal potential, namely temperature to a reacting system. Thermal effects on chemicals, biochemicals and biological materials have long been recognised. Existence of these effects has been used to the advantages of many industries. Thermal activation of chemical reactions and biochemical reaction constitutes a very fundamental process in chemical and biochemical technology. Polymerisation reactions, hydrolysing reactions, oxidation and reduction reactions are few examples of many important processing reactions which may involve thermal processing. In active living tissue, many metabolic reactions can proceed appreciably at room temperature, causing undesirable alteration in the tissue. Low temperature storage has the basic objective of arresting the various reactions which may cause spoilage and which proceed at higher temperatures. With active proteins like enzymes and living tissue, denaturation and functional inactivation can occur rapidly at processing temperatures. Sterilization of microorganisms, pasteurisation of milk are specific examples of this type of thermal processing

    Thermal food processing computation software

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    The objective of this research consisted of developing the two following thermal food processing software: “F-CALC” is software developed to carry out thermal process calculations based on the well-known Ball's formula method, and “OPT-PROx” is software for thermal food processing optimization based on variable retort temperature processing and global optimization technique. Time-temperature data loaded from Excel-file is used by “F-CALC” software to evaluate the heat penetration parameters jh and fh, as well as to compute process lethality for given process time or vice versa. The possibility of computing the process time and lethality for broken heating curves is included. The diversity of thermal food processing optimization problems with different objectives and required constraints are solvable by “OPT-PROx” software. The adaptive random search algorithm coupled with penalty functions approach, and the finite difference method with cubic spline approximation are utilized by “OPT-PROx” for simulation and optimization thermal food processes. The possibility of estimating the thermal diffusivity coefficient based on the mean squared error function minimization is included. The “OPT-PROx” software was successfully tested on the real thermal food processing problems, namely in the case of total process time minimization with a constraint for average and surface retentions the “OPT-PROx” demonstrates significant advantage over the traditional constant temperature processes in terms of process time and final product quality. The developed user friendly dialogue and used numerical procedures make the “F-CALC” and “OPT-PROx” software extremely useful for food scientists (research and education) and engineers (real thermal food process evaluation and optimization)

    Rapid thermal processing of CuAISe2

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    CuAl thin film metallic precursors were selenised using a tube furnace or a rapid thermal processor (RTP). A comparison is made between the two processes for slightly Cu rich films and best crystallographic and elemental properties are obtained for films selenised by RTP: it was found that ternary compound could only be formed using the RTP. In both cases a large amount of CuxSey grains are found to develop at the surface of the films. Only samples processed in the RTP showed cathodoluminscence excitation at 2.68 eV characteristics of the electronic bandgap. Al rich samples were used to study the effect of etching the CuxSey phases from the surface in order to reveal the underlying CuAlSe2 material

    Effect of thermal and non-thermal treatment on the quality of honey: a review

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    In recent year, there has been an increasing amount of studies on the quality of honey particularly physicochemical properties and its nutritional value. Unfortunately, these properties will be affected when it is exposed to a temperature higher than 60°C during the conventional thermal processing and also altered its nutritional properties such as antioxidant activity and brown pigment formation. Hence, non-thermal processing that might be proven to be significant benefit, applied without causing significant heating that can damage taste, texture and nutritional value of honey. Although there are many research has been done on non-thermal processing on the bio-compounds in various foods in various foods, the application of non-thermal processing for the enhancement of the quality of honey is underexplored. By studying the effects of non-thermal processing on the quality of honey, it will help to improve the use of honey and also a diversification in food products containing it

    Rapid Thermal Processing (RTP) of semiconductors in space

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    The progress achieved on the project entitled 'Rapid Thermal Processing of Semiconductors in Space' for a 12 month period of activity ending March 31, 1993 is summarized. The activity of this group is being performed under the direct auspices of the ROMPS program. The main objective of this program is to develop and demonstrate the use of advanced robotics in space with rapid thermal process (RTP) of semiconductors providing the test technology. Rapid thermal processing is an ideal processing step for demonstration purposes since it encompasses many of the characteristics of other processes used in solid state device manufacturing. Furthermore, a low thermal budget is becoming more important in existing manufacturing practice, while a low thermal budget is critical to successful processing in space. A secondary objective of this project is to determine the influence of microgravity on the rapid thermal process for a variety of operating modes. In many instances, this involves one or more fluid phases. The advancement of microgravity processing science is an important ancillary objective

    Microstructural evolution in materials during thermal processing

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    Copyright © 2012 Joseph K. L. Lai et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.This article has been made available through the Brunel Open Access Publishing Fund.This article is made available through the Brunel Open Access Publishing Fund

    Study of Combined Cleaning Process of Sunroot Tubers

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    Elaboration and improvement of the process of raw material cleaning is an urgent scientifically technical process. The one of most prospective directions of vegetables cleaning process intensification is the elaboration of combined methods of their cleaning. The improvement of tubers cleaning process is based on the combination of thermal processing of sunroot tubers by steam and the process of further mechanical additional cleaning.The experimental studies of the influence of parameters of the process of sunroot thermal processing by steam on a tuber surface layer transformation were carried out. The influence of the steam pressure and the duration of the process of tubers thermal processing on the depth of the thermal processing of tuber surface layer and also on the effectiveness of the peel separation were studied. At the same time there were realized the studies as to the influence of the duration of tubers mechanical additional cleaning process on cleaning quality parameters. The experimental apparatus and correspondent method that allow to carry out investigations of the combined process of sunroot tubers cleaning with a possibility to determine the influence of all its parameters on the percent of raw material losses and cleaning quality were elaborated. Rational regimes of the combined process of sunroot tubers cleaning were established