The Use of Contact Heat Generators of the New Generation for Heat Production

We substantiated the need for searching for, and realization of, fundamentally new approaches, using more efficient physical, heat-mass-exchanging and aerodynamic processes, which will make it possible to improve energy effectiveness and ecological cleanliness of heat generation in the systems for individual and decentralized heat supply.For the heat supply to large cities and industrial regions, we examined the advantages of using highly efficient contact heat-generators of different types, which include compactness due to low metal consumption and, as a result, attractive price.It is proposed to use a heat-generator of contact type of the new generation, with the aid of which it was possible to solve a set of problems on the qualitative combustion of fuel and effective heat exchange of gases with the heated water. The use of tubular technology for the combustion of gas is its special feature. Due to it, quality heat exchanging characteristics are provided.In view of further studies, we presented the relevance of creating heat-generators with the use of highly effective hydrogen technologies, which will make it possible to devise the new energy paradigm of heat supply for residential areas and industrial zones through the possibility of accumulation of electrical energy and accumulation of hydrogen

Assessment of Efficiency of Drying Grain Materials Using Microwave Heating

We present results of experimental work on studying the drying of a dense layer of grain using microwave heating. We investigated a series of techniques to supply heat to grain to assess energy efficiency of a microwave field. We studied the following ways of drying: a microwave method, a pulsating microwave method, a microwave-convective cyclic method with blow of a layer with heated air flow and air without preheating, simultaneous microwave-convective drying method.Studying the kinetics of drying in a microwave field showed that we can divide the process into heating periods (zero drying rate), constant (first drying rate) and falling (second drying rate). These periods are characteristic for drying of colloidal capillary-porous bodies at other methods of heat supply. We obtained empirical relationships for the drying rate and the average temperature of grain in the first period based on the generalization of experimental data on the study on drying of grain of buckwheat, barley, oats, and wheat. We presented kinetic dependences in a dimensionless form. They summarize data on the studied grains. The aim of comprehensive studies of various methods of heat supply during drying was determination of the optimal method and rational operational parameters, which ensure high intensity of the process and the required quality of the finished product with minimal energy consumption.All studies took place under identical conditions and for the same grain (oats) to ensure the accuracy of the comparison. We determined that the most preferable method is a simultaneous microwave-convective energy supply without air preheating, which minimizes specific energy consumption. Experimental studies on drying using a microwave field made possible to select the required process parameters: power, heating rate, mass, and form of loading. We plan to develop a technology for drying of grain using microwave energy based on the study dat

Research of Wheat Drying in a Microwave and Combined Filter-microwave Dryer

The aim of the conducted study is to determine kinetics of the complex effect of microwave energy supply and filter drying of the process of water release from the wheat layer. There is offered a combination of MW and filter drying. A special feature of this combination must be its more effectiveness and high speed of water elimination from surface layers of wet seeds and, as a result, the productivity increase of the drying way, decrease of specific energy consumption.There was determined the influence of the specific load of the material, radiator power on processes of microwave and filter-microwave drying of wheat seeds. There were compared microwave, filter-microwave and convective drying of seeds by parameters of specific energy consumption, drying speed.The specific energy consumption at microwave drying of seeds was 4 MJ/kg, at filter-microwave drying 3.8 MJ/kg that is lower than existent convective dryers. The speed of microwave drying changes from 0,5 to 3 %/min, filter-microwave – from 0.3 to 0.7 %/min. The speed is at the level of standard convective dryers.The conducted studies allow to recommend a new combined way of FMW drying of seeds with low energy consumption.Revealed features of heating and drying are possible to be used at developing industrial dryers.The base of experimental data is possible to be used for optimizing and determining effective conditions of MW and FMW drying

Assessment of Efficiency of Drying Grain Materials Using Microwave Heating

We present results of experimental work on studying the drying of a dense layer of grain using microwave heating. We investigated a series of techniques to supply heat to grain to assess energy efficiency of a microwave field. We studied the following ways of drying: a microwave method, a pulsating microwave method, a microwave-convective cyclic method with blow of a layer with heated air flow and air without preheating, simultaneous microwave-convective drying method.Studying the kinetics of drying in a microwave field showed that we can divide the process into heating periods (zero drying rate), constant (first drying rate) and falling (second drying rate). These periods are characteristic for drying of colloidal capillary-porous bodies at other methods of heat supply. We obtained empirical relationships for the drying rate and the average temperature of grain in the first period based on the generalization of experimental data on the study on drying of grain of buckwheat, barley, oats, and wheat. We presented kinetic dependences in a dimensionless form. They summarize data on the studied grains. The aim of comprehensive studies of various methods of heat supply during drying was determination of the optimal method and rational operational parameters, which ensure high intensity of the process and the required quality of the finished product with minimal energy consumption.All studies took place under identical conditions and for the same grain (oats) to ensure the accuracy of the comparison. We determined that the most preferable method is a simultaneous microwave-convective energy supply without air preheating, which minimizes specific energy consumption. Experimental studies on drying using a microwave field made possible to select the required process parameters: power, heating rate, mass, and form of loading. We plan to develop a technology for drying of grain using microwave energy based on the study dat

Influence of the thermal factor on the composition of electron-beam high-entropy ALTiVCrNbMo coatings

This paper reports results of studying the element and phase compositions of electron-beam coatings based on the high-entropy alloy AlTiVCrNbMo, depending on the deposition temperature (in the range of 300...700 °С). The high-entropy alloys were melted in an arc furnace in an atmosphere of high-purity argon. Vacuum condensates of the high-entropy alloy (AlTiVCrNbMo) with a thickness of 3–5 µm were obtained in the vacuum setup UVN-2M-1 at a working vacuum of 5·10-5 mТоrr. The alloy evaporation was performed from the water-cooled ingot mold using an electron-beam gun with a power of 5 kW. Condensation of vapors of all the elements of the alloy was performed onto copper substrates at temperatures of 300, 500, 700 °C. Based on analysis of the element composition of materials of the target made of the high-entropy six-element alloy AlTiVCrNbMo and electron-beam coatings, based on it, we established the critical parameter (specific heat of vaporization of an element) that defined a selective change in the element composition. In accordance with a characteristic change in the composition of coatings of the multi-element high-entropy alloy, 3 groups of elements were distinguished: with a specific heat of evaporation of 280...350 kJ/mol (group 1), 420…460 kJ/mol (group 2), and 590…680 kJ/mol (group 3). It was shown that the formation of a single-phase coating of the high-entropy alloy (based on BCC of the crystalline lattice) occurs at the higher deposition temperature of 500...700 °C when the coating consists of not less than 5 elements. It was established that based on the conditions for an electron-beam process of materials formation, the results obtained can be divided into two types: those determined by the condition of evaporation of the target and those determined by the conditions of coating deposition. The density of flows of elements, evaporated from the target, is determined by their specific heat of evaporation. However, the ratio of atoms in the flow, derived in this way, may not be retained in the formed coating due to the secondary evaporation of elements from the growth surface. The obtained results allow us to substantiate principles for the selection of components for achieving the optimal element and phase compositions of high-entropy alloys.На основі аналізу елементного складу матеріалів мішені з високоентропійного шестиелементного сплаву AlTiVCrNbMo і електронно-променевих покриттів на його основі встановлено критичний параметр (питома теплота випаровування елемента), який визначає селективну зміну елементного складу. Показано, що формування однофазного покриття високоентропійного сплаву відбувається, коли до складу покриття входить не менше 5 елементів. Отримані результати дозволяють обґрунтувати принципи підбору компонент для досягнення оптимальних елементного та фазового складу високоентропійних сплавів

Investigation of Photoelectric Converters with a Base Cadmium Telluride Layer with a Decrease in Its Thickness for Tandem and Two-sided Sensitive Instrument Structures

Photovoltaic cells with a base layer of cadmium telluride with a decrease in its thickness are studied. It is known that the widespread use of photovoltaic converters is constrained by their high price in the case of highly efficient instrument structures, or low efficiency. The creation of tandem and two-sided sensitive photoelectric converters will reduce their cost while increasing their efficiency. However, to create tandem and two-sided sensitive photoelectric converters, the necessary conditions are the use of transparent contacts and a decrease in the thickness of the base layer for efficient absorption of incident radiation by the converter, which is lower. In the research process, it was found that reducing the thickness of the base layer to 1 μm allows to increase the efficiency of the photoelectric transducer during irradiation from the back. An increase in the efficiency of the photoelectric converter occurs due to a decrease in the distance from the generation region of nonequilibrium charge carriers in the region of separation. If the thickness of the base layer is less than 1 μm, then regardless of which side of the irradiation is carried out, a decrease in the efficiency of the instrument structure is observed. Increase in the efficiency of photoconverters is associated with an increase in the negative influence of recombination processes on the back contact, a decrease in the number of charge carriers generated due to incomplete absorption of incident radiation, and a decrease in the volume of the built-in field of the separating barrier when it overlaps with the depletion region of the back contact. ITO/CdS/CdTe/Cu/ITO SCs with a base layer thickness of 1 μm demonstrates degradation stability. The highest value of efficiency in the case of illumination from the front side 8.1 % and with illumination from the back side 3.8 % received after a year of operation of the photovoltaic converter

Improving the Technique of Scrambled Desserts Using the Food Supplement “Magnetofood”

For improving the technology of scrambled dessert products, a food supplement, based on the nanopowder of oxides of two- and trivalent iron “Magnetofood” was introduced in the recipe composition. The object of the studies is base recipes: one of mousse “Cranberry” and sambuk “Apple”. For determining technological characteristics and quality parameters, conventional standard methods were used.It has been established, that introduction of the food supplement “Magnetofood” in amount 0,1 %, 0,15 %, 0,2 % of the recipe mixture mass improves consumption properties of scrambled desserts. The mean value of the organoleptic analysis increases by (1,25±0,1) points. The density also decreases by (29±1) kg/m3 for mousses, by (26±1) kg/m3 for sambuks, and scrambling duration – by ~ 3 minutes. At storing during 24 hours at h=(90±2) %, the microbial contamination of the surface of samples decreases – QMAFAnM in 10 times, yeasts – in 2 times, molds – in 2 times.It has been established, that introduction of the supplement “Magnetofood” favors the growth of the foam-creating ability in average: by (40±2) % for mousses, by (55±3) % for sambuks. The porosity increases by (14,3±0,7) % for mousses, by (12,7±0, 6) % for sambuks. The foam structure stability of scrambled desserts improves by (14±1,1) %. The food supplement “Magnetofood” also raises the effective viscosity by (32 ±1) Pa·s for mousses and by (41±2) Pa·s for sambuks and the mechanical strength of scrambled desserts in 1,23 times.The highest parameters were inherited to mousses and sambuks with supplement “Magnetofood” mass share 0,15 %.There have been experimentally substantiated scrambling technological parameters and regimes of recipe mixtures of berry-fruit mousses and sambuks, modified by the food supplement “Magnetofood”. The total scrambling duration is (14–16) minutes. The initial scrambling speed of the berry-fruit base is (2,0–2,2) s-1, at that the scrambling time is (5–6)·60s. Then the recipe mixture is scrambled at speed (3,3–3,5) s-1 during (3–4)·60s. Scrambling is finished at speed (2,0–2,2) s-1. The distinctive feature of the improved technology is premixing of the food supplement “Magnetofood” with gelatin, realized before the technological operation of soaking gelatin in cold water.The obtained experimental data may be used at developing innovative technologies of scrambled dessert products with the food supplement “Magnetofood”

Development of Innovative Method of Steel Surface Hardening by a Combined Chemical-thermal Treatment

The aim of the article is a hardening of the surface steel layers due to the combination treatment. Samples of steel 38Cr2MoAl were hardened by complex chemical and thermal treatment such as carburizing and subsequent boriding. It was established that surface double-layer hardening for steel 38Cr2MoAl with sequential saturation with atomic carbon (during carburizing) and atomic boron (during furnace boriding) at different temperatures allowed to form a boride layer with transition zone.The obtaining transition zone can improve operational properties of machine parts and tools by micro-friability reduction of diffusion layer. An optimal mode of complex chemical-thermal treatment (CTT) was obtained for the regime, which includes carburizing at 950 °C for 2 hours, boriding at 950 °C for 2 hours, which allows to get the best value for the surface hardness of 22 GPa with a maximum overall diffusion layer 1.4 mm. Due to the technology of combined treatment we can significantly reduce treatment time compared to traditional hardening means and significantly improve product performance properties due to the transition zone between the borides and the matrix of machine elements. The technology can be used in enterprises where there is any hardening furnace without additional installation or conversion of equipment

Study of the Influence of Meals of Wheat and Oat Germs and Wild Rose Fruits on the Fermenting Microflora Activity of Rye-wheat Dough

The aim of the research was to study an influence of meals of wheat germs (WGM) and oat germs (OGM) in amount 10…20 %, and also ones of wild rose fruits (WRFM) in amount 2…6 % of the total mass of flour on the fermenting microflora of rye-wheat dough; and also to establish an influence of the experimental supplements on main microbiological processes in it.It has been established, that adding experimental meals favors the activation of bakery yeast. At introducing WGM, OGM and WRFM, its lifting force grows by 16.0–54.0, 6.0–18.0, 10.0–44.0 % respectively, and zymase and Maltase activity – by 16.0–53.3, 6.0–17.7 and 11.1–44.0 % and 18.8–55.0, 6.3 31.3 and 7.5–25.0 % respectively. It has been established, that there also takes place the activity increase of lactate bacteria in rye-wheat dough with adding meals of wheat, oat germs and wild rose fruits. It is possible at the expanse of adding an additional nutritive medium with the supplements.Such action of enriching raw materials on the microflora favors intensification of alcoholic and lactate fermentation that is established by data of acid accumulation and gas formation in rye-wheat dough. The counted indices at introducing WGM, OGM, WRFM increase by 39.0, 27.8, 33.9 % and 18.2, 13.6, 16.7 % respectively

The study of melting process of the new plugging material at thermomechanical isolation technology of permeable horizons of mine opening

The article presents the results of experimental and theoretical studies, the purpose of which was to substantiate the technology of drilling wells isolation using new thermoplastic composite material. The basis of the proposed material is gravel, and secondary polyethylene terephthalate acts as a binding material. The use of the proposed insulation material avoids a number of disadvantages specific for traditional grouting mortars. The technology of material application provides its melting in a well by thermomechanical drilling. The article deals with the issues, related to the substantiation of the optimal formulation of a thermoplastic composite material based on secondary polyethylene terephthalate, and the determination of rational operating parameters of thermomechanical drilling, which allow to melt effectively the material at the bottom of a well. The possibility of material application for the insulation of absorbing horizons in borehole conditions has been proved. Based on the analysis of the heat balance at the bottom of a well, the calculation procedure has been proposed and the dependences of the velocity and time of thermomechanical melting of the grouting thermoplastic composite material on the operating parameters of drilling, thermal properties and geometric characteristics of the drill bit, have been determined