Heat Treatment Of Mixture Research Articles

Substantiating technological factors for preparing fermented milk-containing products with a combined composition of raw materials with a long storage period

This paper substantiates and defines the technological parameters for obtaining stable emulsions when making fermented milk-containing products. The object of research was the modes of mechanical and heat treatment of mixtures with a combined composition of raw materials based on dairy and vegetable fats. The task to be solved was to obtain stable emulsions by two-stage homogenization of the cream-vegetable mixture and the heat treatment temperature of the fermented cream-vegetable mixture with a combined composition of raw materials with a fat content of 10 % and 15 %. It is shown that during the homogenization of a cream-vegetable mixture with a mass fraction of fat of 10 %, the pressure in the first stage should be 10.0–12.0 MPa, in the second – 2.5–3.0 MPa; for a cream-vegetable mixture with a mass fraction of fat of 15 %, the pressure in the first stage is 8.0–10.0 MPa, in the second – 2.5–3.0 MPa. Modes of thermomechanical processing of the fermented cream-vegetable mixture at temperatures of 65±2 and 70±2 °C to ensure the microbiological stability of the milk-containing product during storage have been substantiated. A stabilizing system based on milk proteins has been selected. It was established that in order to improve the consistency, increase heat resistance, and avoid foaming of the finished product, it is necessary to perform thermomechanical processing of the fermented cream-vegetable mixture with a fat content of 10 % and 15 % at temperatures of 70±2 °С and 65±2 °С, respectively, and mass fraction stabilizer – 0.5 % and 0.15 %, respectively. The research data do not always coincide with previously established patterns, which is due to the difference in the chemical composition of the studied food systems, as well as the methods of their preparation and use. The results of the work could be used in the technology of milk-containing products with a combined fat composition

Obtaining Electroheating Elements Based on Products of Carbothermal Reduction of Fe2O3 by Waste Activated Sludge (WAS)

In this work, the prospects of fabrication of heating elements from heat-treated (sintered) mixtures of waste-activated sludge (WAS) and Fe2O3 under oxygen deficiency conditions are considered. During heat treatment of mixtures in the 800–900 °C temperature interval, Fe2O3 reduces to Fe3O4, Fe0.94O, and Fe. A heat treatment at 1000 °C leads mainly to the formation of amorphous iron doped with carbon, silicon, and aluminum. Based on these compacted mixtures, having different electrical resistivity (from ~ 10–4 up to 10–1 Ω·m), it is possible to fabricate heating elements, whose working temperature ranges from ~ 100 °C up to 600 °C.Graphical

Oxidation of the zirconium boride-silicon nitride composite in the temperature range 1100–1300°C in air

Composite materials and coatings based on zirconium boride and silicon nitride have been prepared by heat treatment of mixtures of the initial components in air. The chemical reactions result in the formation of the glass melt encapsulating initial particles, which provides an increased heat resistance of the material. The kinetics of high-temperature oxidation of the composite based on the ZrB2-Si3N4 system has been studied. The interaction between solid components of the ZrB2-Si3N4 system, atmospheric oxygen, and the glass melt has been described in terms of the formal kinetic equations for heterogeneous processes. Thermogravimetric, thermal, and X-ray powder diffraction analyses have been carried out, and the electrical resistivity of the compact samples has been determined.

Influence of silicon-containing compounds on the heat resistance of composites based on titanium boride

The reaction formation of composite materials and coatings based on titanium boride, silicon dioxide, and silicon carbide upon heat treatment of mixtures composed of initial components in air has been investigated. It is shown that the glass melt formed in the course of the chemical reaction encapsulates titanium boride and silicon carbide particles, thus imparting the high-temperature strength to the composite material. The influence of the composition, temperature, and heating conditions on the kinetics of oxidation of samples in the form of cast pieces and graphite with coatings during their heat treatment at temperatures of 1000–1300°C is studied using thermogravimetric, differential thermal, and X-ray powder diffraction analyses. The electrical resistivity of the synthesized samples is determined and its dependence on temperature is established. The compositions of coatings that ensure the effective protection of graphite from oxidation in air at high temperatures are proposed from analyzing the results of the performed investigation.

Fluorescence‐based soft‐sensor for monitoring β‐lactoglobulin and α‐lactalbumin solubility during thermal aggregation

A soft-sensor for monitoring solubility of native-like alpha-lactalbumin (alpha-LA) and beta-lactoglobulin (beta-LG) and their aggregation behavior following heat treatment of mixtures under different treatment conditions was developed using fluorescence spectroscopy data regressed with a multivariate Partial Least Squares (PLS) regression algorithm. PLS regression was used to correlate the concentrations of alpha-LA and beta-LG to the fluorescence spectra obtained for their mixtures. Data for the calibration and validation of the soft sensor was derived from fluorescence spectra. The process of thermal induced aggregation of beta-LG and alpha-LA protein in mixtures, which involves the disappearance of native-like proteins, was studied under various treatment conditions including different temperatures, pH, total initial protein concentration and proportions of alpha-LA and beta-LG. It was demonstrated that the multivariate regression models used could effectively deconvolute multi-wavelength fluorescence spectra collected under a variety of process conditions and provide a fairly accurate quantification of respective native-like proteins despite the significant overlapping between their emission profiles. It was also demonstrated that a PLS model can be used as a black-box prediction tool for estimating protein aggregation when combined with simple mass balances.

Physicochemical aspects of graphite protection from oxidation in heat treatment of mixtures on ethyl silicate binder

Results of a study of the physicochemical processes that occur in heat treatment of graphite — ethyl silicate binder mixtures are presented. Diffusion “bridges” in plane 0001 of graphite between the latter and SiO2 gel confirm diffusion matching of the ≡ Si — O — Si ≡ and ≡ C — C ≡ bonds in heat treatment of the mixtures at 1223 K with the formation of β-SiC, which diminishes the oxidation of graphite.

Structure and Properties of Loaded Rubber Mixtures. X. Alteration of Carbon Black Structures by Heat Treatment

Abstract 1. Raising the temperature of vulcanizates containing carbon black causes changes in the carbon structures, which can be estimated by the value of specific electric resistivity ρ and the index n in the equation: I=cVn, relating the strength of the current I with the voltage V. 2. These changes are nearly independent of the type of rubber and are governed chiefly by the type of carbon black. 3. The change of electric resistivity of vulcanizates with temperature follows an exponential law, and can be expressed by the equation : ρt=ρ0 eαt. 4. The sign of the coefficient α is negative for vulcanizates containing channel carbon black, and positive for those containing nozzle black or lamp black. 5. Heating of vulcanizates (up to 100°) for 30 minutes causes destruction of the nozzle black and lamp black particles, but causes little apparent destruction of channel black structures. 6. Prolonged heating (10 hours or more) at temperatures above 60° C causes destruction of the particles of all the carbon blacks studied. This detruction is more extensive in the case of nozzle and lamp blacks than in the case of channel black. 7. During heat treatment of mixtures containing channel black, it is chiefly the carbon-rubber bonds that are destroyed (the index n decreases); whereas in mixtures containing nozzle, furnace and lamp blacks, it is chiefly the carbon-carbon bonds that are destroyed (the index n increases). 8. The higher the temperature during deformation and relaxation, the greater is the degree of restoration of the carbon structures which are destroyed during deformation. 9. The degree of restoration of the carbon structures under identical conditions of deformation and relaxation of vulcanizates containing nozzle black is greater than that of corresponding vulcanizates containing channel black.