An approach to creating application software for modeling of the deep heat processes (on the example of modeling non-stationary thermal conductivity above a mantle plume in the VLADI GEAD 4.0 MODULE)

The work substantiates the necessity and considers the methodology of own (by the researcher-modeler’s own effort) development of special applied software as a tool for modeling geological processes. The concept of a mantle plume as a system of mantle-crustal migrants, sequentially rising from the core to the fragile earth’s crust through a solid plastic mantle medium by the magma- and/or fluid fracture, is presented. A tool for computer modeling of thermal disturbance above a mantle plume in the process of its vertical development with the ability to save, process and interpret the obtained numerical and graphic information is proposed. Dependences are obtained between the depths of vertical propagation of the plume, geometric and temperature intervals of relaxation of thermal disturbance in the host medium, and geodynamic parameters. A method for assessing the thermal expansion of a medium based on the values of internal iterative variables during program execution is proposed.

Cell model of transient heat processes in underground electric cable and surrounding ground

One of the most essential consequences of short circuits in underground cable networks of 6–10 kV is heating up the insulation with its possible inflammation and damage of adjacent objects of an electrical supply system that enlarge the concomitant damage many times as much. Various methods (including the methods, which are based on reference documents) to calculate the thermal state of underground cables are known. Despite the part of them are of extra complexity and require a lot of poorly identified parameters, the issue of the accuracy of forecasting calculations remains open. Hence, the issue of development of new approaches to model transient thermal processes in a cable, combining the simplicity, small computational time, and the reasonable accuracy of forecasting the process thermal parameters is an important one. The method of mathematical modeling is used to solve the problem. The model uses the mathematical tools of the Markov chains theory. It is adapted to the representation of ground as multilayer medium, and the non-stationary heat source may be placed in one of the layers. The heat transfer deep down into the ground is described by heat conduction, and the heat exchange with neighboring ground and environment is described by heat emission. The study of influence of the process parameters on the heat process behavior is carried out by numerical methods. The experimental validation of the model is not planned at the current stage of this investigation. The developed mathematical model allows predicting temperature in a cable and in surrounding ground depending on the heat capacity and depth of layout of the heat source, determined by the value of current in the cable. The results of numerical experiments come to agreement with the physical essence of the process. The obtained results have the scientific novelty as they are based on the universal algorithm of modeling and allow describing the transient processes in the object under consideration. The authors have proposed a mathematical tool to estimate the heat state of an underground electric cable depending on the heat capacity of the current, its depth of location in the ground and the thermo-physical properties of the ground. The model is simple to operate and takes exceedingly small computational time. It can be easily used in engineering practice.

Forming Comfortable Microclimate in the Bus Compartment via Determining the Heat Loss

Methodology of the heat outcome from the bus compartment in terms of duration factor of cooling and heating capacity is introduced. Value of the air temperature change in the compartment was calculated. The balance method of the spent heat is used to assess the level of keeping a proper temperature environment in the bus saloon when a comfortable microclimate is created for passengers via the proper conditioning system functioning. Models of the heat transmission notions were used for calculation regarding different categories of the heat load creation. A developed numeric algorithm was introduced in the article as well as a program for modelling the transitory heat processes in the compartment of the city bus equipped with an air-conditioner enabling to take into account various constructive decisions in the system of comfortable provision of city buses and model unstable heat processes.

A New Shielding Efficiency of Stator Core End Packets of a Powerful Turbogenerator

On the basis of complex research the electromagnetic and heat processes by means of mathematical and physical simulation, the efficiency for a new constructive solution of stator core end zone of powerful turbogenerator is proved. A design that allows maximum reducing temperature of the stator end packet is proposed. In order to increase reliability of experimental data obtained with the help of scale physical model, as well as testing of constructed mathematical model, using the latest one “adjusted” to physical model, the numerous experiments for studying effectiveness of a tooth-slot configuration shields were carried out. The small difference of magnetic flux density values obtained by means of mathematical simulation from the experimental ones allows drawing a conclusion about the reliability of result. It is shown that use of physical simulation permits investigate the appropriateness of electromagnetic field distribution without exact quantitative indices of parameters and can be applied to research the quality comparison under certain changes of model. When constructing a mathematical model, an approach was used with the help of a consecutive logic transition from a simple model of machine central part to more difficult one of end zone, using the previous results in next allows obtaining the temperature distribution in difficult areas. The heat calculation for rated load condition of turbogenerator type TGV-500 with the help of mathematical model as well as comparison of these results with experimental data for a real generator analogous type and power are made. The differences of calculated and experimental values not exceed 7%. All data obtained by means of both simulation and natural experiment are corresponded to the same turbogenerator that in total makes reliability results of mathematical simulation not obtained in a real object by various reasons of objective and subjective nature.

An approach to creating application software for modeling of the deep heat processes (on the example of modeling non-stationary thermal conductivity above a mantle plume in the VLADI GEAD 4.0 MODULE)

The work substantiates the necessity and considers the methodology of own (by the researcher-modeler’s own effort) development of special applied software as a tool for modeling geological processes. The concept of a mantle plume as a system of mantle-crustal migrants, sequentially rising from the core to the fragile earth’s crust through a solid plastic mantle medium by the magma- and/or fluid fracture, is presented. A tool for computer modeling of thermal disturbance above a mantle plume in the process of its vertical development with the ability to save, process and interpret the obtained numerical and graphic information is proposed. Dependences are obtained between the depths of vertical propagation of the plume, geometric and temperature intervals of relaxation of thermal disturbance in the host medium, and geodynamic parameters. A method for assessing the thermal expansion of a medium based on the values of internal iterative variables during program execution is proposed. Keywords: applied programming, computer modeling, non-stationary thermal conductivity, mantle-crust migrant, adiabatic-geothermal interval, Vladi Gead 4.0.

A cell model of heat conduction in multi-layer medium with variable number of the layers

The heat conduction is an important part of heat transfer processes in power engineering, civil engineering, chemical technologies, etc. Variety of researches is devoted to theoretical and experimental study of the heat transfer by the heat conduction. At present, the considerable attention is concentrated on the heat conduction in media with variable boundaries (the so-called Stephan’s problem). A reason of a boundary motion can be burning-out of material, its wear, its melting with carry-over of a melt, other physic-chemical processes. Analytical solutions to the Stephan’s problem exist only after far-going assumptions, which lead to the loss of their practical value. The development of effective numerical methods of its solution becomes an actual scientific and practical problem. Such methods are to combine universality and physical clearness and convenience for engineering practice. In order to solve the problem, the method of mathematical modeling is used. The model uses the mathematical tools of the theory of Markov chains. It is adapted to the cell model of a medium, in which the number of cells can vary due to this or that mechanism of the edge cells interaction with outside medium. The heat transfer by the heat conduction and the heat interaction with the heat sources are described by the classical heat balance equations. The study of the influence of parameters on the process is performed by numerical methods. A mathematical model that allows describing transient heat processes in a multi-layer medium with variable number of layers is developed. The results of heat process calculation inside a plane wall with the moving boundary form the heat source side due to the boundary thermal distruction at a certain critical temperature are presented. The obtained results are physically consistent and approve the model workability. The principle differences between the heat processes in the walls with immovable and movable boundaries are found. It is shown that the temperature in a wall with moving boundary does not overbalance the critical temperature of the thermal distraction when the wall still exists, and the rate of the wall dimension decrease is growing with its dimension decrease.

Спектральный анализ тепловых флуктуаций в переходных областях предплавления KI

В различных системах вблизи точек фазовых переходов наблюдаются неравновесные флуктуации по типу нелинейного броуновскго шума. Такие неравновесные процессы, как правило, являются предвестниками разрушения и деградации материалов. Наблюдение вблизи точки плавления Tm переходных явлений предплавления, аномальное поведение с температурой некоторых физических параметров, указывают на то, что по мере приближения к точке плавления структура и свойства твердого тела претерпевают изменения, как правило, нелинейно зависящие от скорости нагревания. Для характеристики состояния сложных динамических систем необходимо рассчитать показатель формы флуктуационного спектра, который несет информацию о происходящих в системе процессах ивзаимосвязях различных подсистем. По изменению спектральных характеристик флуктуационных процессов можно судить не только о состоянии системы, но и разрабатывать методики прогноза ее эволюции. Цель настоящей работы – параметризация тепловых флуктуаций в области предплавления ионных кристаллов KI и изучение зависимости спектральных параметров от кинетических режимов нагревания.Для определения спектральных характеристик тепловых флуктуаций в области предплавления KI в различных кинетических режимах использовался вейвлет-анализ. Вейвлетный анализ соединяет возможности, присущие классическому спектральному Фурье-анализу, с возможностями локального исследования различных флуктуационных и колебательных процессов в частотном и временном пространстве. Это позволяет выявлять особенности процессов на различных временах и масштабах эволюции системы. Вейвлет-преобразование колебательных процессов позволило получить информацию о динамике развития сложных систем в различных неравновесных условиях. Показано, что тепловые флуктуации в области предплавления KI представляют собой нелинейный броуновский шум с показателем самоподобия b ~ 2. С помощью показателя Херста определен тип флуктуационного процесса. Показано, что в динамических режимах нагревания (v = 5, 10 К/мин)флуктуационный процесс характеризуется колебательным характером эволюции по типу «устойчивое-неустойчивое» (свойство антиперсистентности), а квазистатических режимах (v = 1 К/мин) – поддерживается первоначальная тенденция эволюции системы (свойство персистентности). ЛИТЕРАТУРА 1. Битюцкая Л. А., Селезнев Г. Д. Тепловой фликкер-шум в диссипативных процессах предплавления. ФТТ. 1999;41(9): 1679–1682. Режим доступа: https://journals.ioffe.ru/articles/viewPDF/355462. Геращенко О. В., Матвеев В. А., Плешанов Н. К., Байрамуков В. Ю. Электрическое сопротивление и 1/f-флуктуации в тонких пленках титана. ФТТ. 2014; 56(7): 1386–1390. Режим доступа:https://journals.ioffe.ru/articles/viewPDF/269403. Клочихин В. Л., Лакеев С. Г., Тимашев. С. Ф. Фликкер-шум в химической кинетике (микроско-пическая кинетика и флуктуации в стационарных химических процессах). 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Changes of Ginsenoside Composition in the Creation of Black Ginseng Leaf

Ginseng is an increasingly popular ingredient in supplements for healthcare products and traditional medicine. Heat-processed ginsengs, such as red ginseng or black ginseng, are regarded as more valuable for medicinal use when compared to white ginseng due to some unique less polar ginsenosides that are produced during heat-treatment. Although ginseng leaf contains abundant ginsenosides, attention has mostly focused on ginseng root; relatively few publications have focused on ginseng leaf. Raw ginseng leaf was steamed nine times to make black ginseng leaf using a process that is similar to that used to produce black ginseng root. Sixteen ginsenosides were analyzed during each steaming while using high-performance liquid chromatography (HPLC). The contents of ginsenosides Rd and Re decreased and the less polar ginsenosides (F2, Rg3, Rk2, Rk3, Rh3, Rh4, and protopanaxatriol) enriched during steam treatment. After nine cycles of steaming, the contents of the less polar ginsenosides F2, Rg3, and Rk2 increased by 12.9-fold, 8.6-fold, and 2.6-fold, respectively. Further, we found that the polar protopanaxadiol (PPD) -type ginsenosides are more likely to be converted from ginsenoside Rg3 to ginsenosides Rk1 and Rg5 via dehydration from Rg3, and from ginsenoside Rh2 to ginsenosides Rk2 and Rh3 through losing an H2O molecule than to be completely degraded to the aglycones PPD during the heat process. This study suggests that ginseng leaves can be used to produce less polar ginsenosides through heat processes, such as steaming.