Thermodynamic Characterization and Equation of State for Solid and Liquid Lead

A high-temperature equation of state (EoS) for the fcc phase of solid lead and liquid lead was developed herein using experimental data on thermodynamic properties, volumetric thermal expansion, compressibility, temperature-dependent bulk modulus, and sound velocity from ultrasonic measurements and melting curve. The whole totality of experimental data was optimized using the temperature-dependent Murnaghan EoS over a pressure range of 0–130 kbar. The temperature dependences of thermodynamic and thermophysical parameters were described herein using an expanded Einstein model. The resultant EoS describes well the whole set of available experimental data within measurement uncertainties of individual parameters.

THERMODYNAMIC PROPERTIES AND THE EQUATION OF STATE OF COPPER

Высокотемпературное уравнение состояния меди получено с использованием экспериментальных данных по термодинамическим свойствам, объемному термическому расширению, сжимаемости, температурной зависимости модуля объемного сжатия. Весь объем экспериментальных данных оптимизирован с использованием температурно-зависящего уравнения Тайта в диапазоне давлений до 2000 кбар и температур от 20-50 K до температуры плавления. Температурная зависимость термодинамических и термофизических параметров описана с использованием расширенной модели Эйнштейна. Полученное уравнение состояния хорошо описывает весь объем экспериментальных данных в пределах погрешности измерений отдельных величин. The high-temperature equation of state of copper is obtained using experimental data on thermodynamic properties, volumetric thermal expansion, compressibility, temperature dependence of the volumetric compression modulus. The entire volume of experimental data is optimized using the temperature-dependent Tate equation in the pressure range up to 2000 kbar and temperatures from 20-50 K to the melting point. The temperature dependence of thermodynamic and thermophysical parameters is described using the extended Einstein model. The resulting equation of state describes well the entire volume of experimental data within the measurement error of individual quantities.

Thermophysical parameters of the Kežmarok sandstone

Thermophysical parameters of building materials are required for calculating the complex heat and water transfer in building structures. It can be performed by modern simulation software such as Wufi, Delphin, Math, Comsol Multiphysics and other. This software is suitable for evaluation of water and heat transport in construction of historical buildings, because it can include the impact of water on material properties, driven rain, ground water, heat and water accumulation and other. The material properties of historical building materials are required for the use of this software. In Slovakia, the most used building material was sandstone. Sandstone from Kežmarok was chosen for this paper, which was used in the construction of historic buildings such as churches and town houses. The method of dynamic impulse transition by thermophysical tester RTB was used to determine the thermal properties of sandstone.

Learning Thermographic Models for Optimal Image Processing of Decorated Surfaces

The use of infrared thermography presents unique perspectives in imaging of artifacts to help interrogate their surface and subsurface characteristics, highlight deviations and detect contrast. This research capitalizes on active and passive thermal imagery along with advanced machine learning-based algorithms for pre- and post-processing of acquired scans. Such codes operate efficiently (compress data) to help link the observed temperature variations and the thermophysical parameters of targeted samples. One such processing modality is dictionary learning, which infers a “frame dictionary” to help represent the scans as linear combinations of a small set of features, thus training data to show a sparse representation. This technique (along factorization and component analysis-based methods) was used in current research on ancient polychrome marquetries aimed at detecting aging anomalies. The presented research is unique in terms of the targeted samples and the applied approaches and should provide specific guidance to similar domains.

Experimental determination of physico-chemical and disperse characteristics and thermal parameters of sheep tail fat

The article discusses the experimental determination of the level of salinity, melting temperature, dispersed composition of crushed sheep tail fat, its moisture content and analysis of the state of moisture in it, and presents the results of these studies. The information obtained is necessary because the approach recommended by the authors contributes to a longer storage of the final product. Systematization of the advantages and disadvantages of the known technologies of smoked sheep tail fat, will allow to compose a rational technological flow of the production of this product and also to determine the rational operating parameters of the implementation of its stages. The information presented in the article on the physicochemical and dispersed characteristics, as well as the thermophysical parameters of sheep tail fat is relevant. At present, researchers have increased their interest in extruded products with a developed structure, obtained on the basis of raw materials of animal origin, as a source of high-quality fats, as well as a basis for therapeutic and prophylactic nutrition products of various technological forms.

RESEARCH INTO THE THERMOPHYSICAL CHARACTERISTICS OF MUSCLE AND ADIPOSE TISSUES IN THE FREEZING–THAWING PROCESS

The paper presents a study of the thermophysical characteristics of meat systems based on minced beef and pork with different morphological composition in the freezing–thawing process, and those of model systems based on minced beef with addition of adipose tissue (raw fat). The method used to detect and compare the thermodynamic changes consisted in determining the effective specific heat capacity by freeze-thaw thermograms and was based on a set of informational parameters related to it (cryoscopic temperature, cryoscopic interval of temperatures, specific heat of phase transition in the cryoscopic temperature interval, change of enthalpy in the interval of temperatures of the sample tested, proportion of moisture that changes its physical state in the cryoscopic temperature interval). It has been shown that the morphological structure of meat (the ratio of muscle, connective, and adipose tissues) significantly affects the thermophysical parameters of meat systems during freezing and defrosting. It has been found that under the conditions of a freeze–thaw cycle, an increase in the content of connective tissue leads to a higher proportion of moisture that changes its physical state in the cryoscopic temperature interval, while an increase in the adipose tissue content in a meat system reduces the moisture that changes its physical state in the cryoscopic temperature interval. When adipose tissue was introduced into meat systems, the freezing process resulted in a higher rate of formation of ice crystals and a lower rate of moisture migration from cells to the intercellular space, and crystal formation became a controlled process. When manufacturing semi-finished frozen meat products, regulating the ratio of muscle and adipose tissues makes it possible to influence the stability of the properties of meat systems in the technological cycle “freezing – storage – thawing” and to create products with the required functional, technological, and thermophysical parameters. This research can be a basis for developing the recipe compositions and technological parameters of manufacturing semi-finished frozen meat products and finished products based on them

Physico-chemical properties and structural transformations in the synthesis of boroalumosilicate glass-crystal materials

The aim of this work is to study the areas of glass formation and metastable liquation of the pseudo-ternary system (MgO·Al2O3)-B2O3-SiO2, and study of the crystallization process of glasses of cordierite composition. The crystallization process of glasses of cordierite composition containing B2O3 by a single-stage heat treatment at 1000 oC and 1200 oC, the nature of crystallization, the thermal properties of glasses and glass crystalline materials of the system (MgO·Al2O3)-B2O3-SiO2 were studied. It revealed that during the isolation of a boron-containing solid solution, the residual glassy phase enriched with oxides of MgO and Al2O3, which lead to an increase in the thermal expansion coefficient of the glass phase. The research results provide possibility to synthesize glass-ceramics with certain thermophysical parameters by stopping further glass crystallization at the stage of formation of a certain amount and ratio of the required crystalline and glassy phases.

Various Thermal Coefficients İnvestigation of 3C-Sic Nanoparticles at the Different Heating Rates

Several thermal parameters were analyzed for nanocrystalline silicon carbide (3C-SiC) particles at the performed depending on the thermal processing rate. The hydroxyl groups on the surface of nanocrystalline 3C-SiC particles have been investigated as a function of temperature and heating rate. Specific heat capacity and Gibbs energy of silicon carbide nanoparticles have been determined in the temperature range of 300 ÷ 1270K at the various heating rates. The enthalpy and the entropy were calculated at different thermal processing rates (theoretical calculations are confirmed based on experimental results). Experminetal results obtained for all thermophysical parameters were comparatively studied at different thermal processing rates.PACS: 61.46.+w, 65.80.+n, 67.80.Gb