Influence of Heat Treatment Parameters on the Functional Behavior and Corrosion Performance of a Shape Memory Wire Actuator

In the present study, the effect of heat treatment parameters on the functional response, corrosion behavior and microstructural evolution of NiTi shape memory alloys were investigated. Various heat treatment regimes were utilized to study the impact of temperature and duration on the actuation behavior of wire samples under bending. Results clarified that austenite transformation temperatures As and Af increased at higher treatment temperatures. Cyclic response in the range of 0 to 15 degrees indicated that the actuation force exhibits an inverse relation with the treatment temperature. Higher treatment durations below 500°C elevated both the hardness and the sustained load. Bending force levels above 1500gf were achieved after a 90 min treatment at 400°C, whereas that over 500°C brought about a noticeable drop in strength. Investigations on the corrosion behavior of NiTi alloy was utilized in the simulated body fluid revealing that the sample heat treated at 400°C for 90 min showed the highest corrosion resistance.

Whole and quality grits yield of emmer wheat grain depending on endosperm consistency and water-heat treatment

The article is devoted to the determining of the effect of water-heat treatment regimes (moistening and softening) and hulling during the production of whole grits of emmer wheat with different vitreous endosperm. A comparative analysis of grits products yield was made, depending on the studied factors, and the optimal regimes are determined taking into account the culinary assessment of the finished product. During the production of whole grits of emmer wheat, the optimal to hull vitreous grain of moisture content 12.0–13.0%. The duration of hulling of such grain should be 40–120 s (grits yield 92–97%) to production high quality cereals and 120–140 s (grits yield 86–90%) – with very high.

An enhanced technology of pear compote production through direct blanching with sugar syrup in glass jars and a device for its implementation

In this article we review and propose new technical solutions to improve the production technology of pear compote with the use of a new method of advanced preparation of fruits through blanching them with sugar syrup in glass jars and accelerated pasteurization modes. The effectiveness of the use of blanching fruits in sugar syrup directly in jars after packing and before filling with syrup, as opposed to blanching them in various technological liquids, is scientifically substantiated. To implement this method, a device for heating fruits in jars in heat transfer fluid has been developed and used. The use of blanching fruit in sugar syrup in jars and accelerated heat treatment regimes intensifies the thermal processing and, as a result, reduces the duration of pasteurization regimes and improves the product quality from the point of view of biologically active components contents. It was revealed that blanching the fruit in jars with 5% sugar syrup at a temperature of 95 °C followed by a syrup with a temperature of 98 °C provides the initial temperature of the product in a jar of 75–76 °C, while according to traditional technology the temperature of the product before sealing is within 45–48 °C. Based on the experimental studies, new modes of pasteurization of pear compote have been developed, taking into account the increased temperature of the product in the jars before sealing. Comprehensive evaluation of the results of the studies allows us to conclude that the implementation of the proposed technical solutions in the production of pear compote, as ensuring the safety of the finished product and improving its quality, is effective.

Comparative evaluation of approaches to modelling kinetics of microbial thermal death as in the case of Alicyclobacillus acidoterrestris

Microbial death kinetics modelling is an integral stage of developing the food thermal sterilisation regimes. At present, a large number of models have been developed. Their properties are usually being accepted as adequate even beyond boundaries of experimental microbiological data zone. The wide range of primary models existence implies the lack of universality of each ones. This paper presents a comparative assessment of linear and nonlinear models of microbial death kinetics during the heat treatment of the Alicyclobacillus acidoterrestris spore form. The research allowed finding that single-phase primary models (as adjustable functions) are statistically acceptable for approximation of the experimental data: linear – the Bigelow’ the Bigelow as modified by Arrhenius and the Whiting-Buchanan models; and nonlinear – the Weibull, the Fermi, the Kamau, the Membre and the Augustin models. The analysis of them established a high degree of variability for extrapolative characteristics and, as a result, a marked empirical character of adjustable functions, i.e. unsatisfactory convergence of results for different models. This is presumably conditioned by the particularity and, in some cases, phenomenology of the functions themselves. Consequently, there is no reason to believe that the heat treatment regimes, developed on the basis of any of these empirical models, are the most effective. This analysis is the first link in arguing the necessity to initiate the research aimed at developing a new methodology for determining the regimes of food thermal sterilisation based on analysis of the fundamental factors such as ones defined spore germination activation and their resistance to external impact.

The Effect of Heat Treatment Regimes of Polyphenylene Sulfides on their Thermal Properties

Thermal and thermo-oxidative degradation, as well as crosslinking and "curing" processes of polyphenylene sulfide, depending on the heat treatment regimes, have been studied using gas chromatography. The effect of sorbed water in the polymer on the processes of thermal and thermo-oxidative decomposition of polyphenylene sulfide is shown and the optimal modes of drying the samples are established.