Intensification of Polysaccharides Extraction from Plant Raw Materials under the Influence of Electric Current

The article presents the results of the studies of the intensification of the processes of extraction of water-soluble polysaccharides from plant raw materials – medicinal hyssop (Hyssopus officialis L.) under the action of an electric current. The effect of direct, alternating, and pulsed electric currents on the degree of polysaccharides extraction was studied in comparison with the traditional pharmacopoeiсal method. It is shown that the energy consumption for the extraction process, intensified by a pulsed electric current, is significantly lower compared to extraction by convection heating. At the same time, the use of electric current makes it possible to reduce the limiting processing temperature from 70 °С to 40 °C, this will allow in the future to obtain not only aqueous, but also aqueous-alcoholic and alcoholic extracts, and, consequently, to extract biologically active non-soluble in water substances.

Study of properties of acrylic, epoxy and epoxy acrylic compositions structured by the methods of convection heating and heating in the field of high-frequency current

This work is devoted to the development and study of the processes of accelerated structuring of polymer composite materials in the field of high-frequency current (microwave field) which are used in the electronic and instrument-making industries, etc. The complex of properties and the features of structuring of epoxy, acrylic and epoxy acrylic polymer composite materials in the microwave field are investigated. In comparison with the traditional method of structuring and polymerization (convection heating), the structuring in the microwave field equally affects the properties of the studied polymer composite materials, regardless of the chemical nature of the oligomer. The action of the microwave field for all studied polymer composite materials causes an increase in the degree of conversion of binders and a decrease in the content of residual monomer (methyl methacrylate) in thermoplastic acrylic polymer composite materials. In addition, the microwave treatment provides the completeness of chemical and physicochemical processes of the formation of rational structure of polymer composite materials with stable properties. The conducted research allows recommending various regimes of the structuring of the studied polymer composite materials taking into account operating conditions. These regimes ensure the reduction of structuring duration and provide a high level of mechanical and operational properties.

Influence of the Heating Method on the Efficiency of Biomethane Production from Expired Food Products

The aim of the study was to determine the effect of heating with microwave electromagnetic radiation (EMR) on the efficiency of the methane fermentation (MF) of expired food products (EFP). The research was inspired by the positive effect of EMR on the production of biogas and methane from different organic substrates. The experiment was carried out on a laboratory scale in fully mixed, semi-continuous anaerobic reactors. The technological conditions were as follows: temperature, 35 ± 1 °C; organic load rate (OLR), 2.0 kgVS·m−3∙d−1; and hydraulic retention time (HRT), 40 days. The source of the EMR was a magnetron (electric power, 300 W). There was no statistically significant influence of the use of EMR on the achieved technological effects of MF. The efficiency of biogas production was 710 ± 35 dm3·kgVS−1 in the variant with EMR and 679 ± 26 dm3·kgVS−1 in the variant with convection heating (CH). The methane contents were 63.5 ± 2.4% (EMR) and 62.4 ± 4.0% (CH), and the cumulative methane production after 40 days was 271.2 and 288.6 dm3CH4, respectively.

The potential use of new impulse fire-fighting machinery for qualitatively new large-scale disinfection

Introduction. This paper is an overview of the use of standard equipment capable of spraying disinfectants and powders and fi ghting viral infections during a pandemic.Aims and objectives. The objective of the paper is to substantiate the need to develop a new method of combined disinfection. The following problems are to be tackled to meet this challenge: 1) the study of shock waves and their effi ciency if applied to microorganisms; 2) the substantiation of the effi cient use of the available fi re-fi ghting machinery, standard charges and sample equipment for shock-wave disinfection; 3) the search for the optimal and effective cycle of large-scale disinfection; 4) the compatibility substantiation of the shock-wave mode of large-scale spraying of chemical disinfectants; 5) the development and adjustment of impulse fi re-fi ghting equipment to ensure fl exible disinfection control in a wide range of areas.Materials and methods. The weaknesses of disinfection by spraying disinfectants and the impossibility of their elimination by upgrading traditional hydraulic and pneumatic equipment, without changing their operating principles, have been demonstrated.Results and discussion. A new disinfection method, based on the accumulated experience of operation of impulse fi re equipment, is proposed. A disinfection methodology that contemplates the shock-wave destruction of microorganisms has a strong potential. The optimal cycle of spraying disinfectant chemical solutions (DCS) and powders has been substantiated; it assures comprehensive disinfection based on various mechanisms of action: 1) impact compression and prompt heating; 2) pressure relief that destroys microorganisms; 3) convection heating using a squall front that has high-temperature steam whirls; 4) chemical disinfection using micro-drops and DCS vapors sprayed on various surfaces that have irregularities, slots, cracks, irregular shape items.Conclusions. The proposed advanced equipment has no close substitutes in the world. It is protected by the Russian, Ukrainian and Chinese patents. Its production is expedient if launched at defense plants in operation if suffi cient funding is available.

Thermal Comfort Analysis of Combined Radiation-Convection Floor Heating System

In this paper, a novel combined radiation-convection floor heating system is shown. This study uses practice-based learning and investigated the thermal performance of a combined radiation-convection floor heating system with a water heat pump system by evaluating the thermal environment and energy consumption in an experimental test. A new method that analyzed the thermal performance of four different controls was developed and applied. The results of the surface temperature distributions demonstrated that Mode 1, which uses only convection, had the lowest floor temperature and was thus considered inappropriate for occupants who sleep on the floor. By contrast, Modes 2, 3, and 4 showed high floor surface temperatures as hot water was supplied to the radiant heating panel. The predicted mean vote (PMV) results suggest that radiant floor heating is not appropriate for intermittent heating. In other words, occupants of single residences who return home at night will experience a long period of discomfort if they heat their room using floor heating. In this case, Mode 1, which is convection heating, and Modes 3 and 4, which represent mixed modes provide a more comfortable environment. The difference between this experimental study and previous research is that four different control modes for a combined radiation-convection system were evaluated based on the same location of the equipment in a laboratory. Furthermore, we studied the long-term real-scale thermal performance using panel and energy consumption.

INFLUENCE OF VARIOUS FACTORS ON RADIANT AND CONVECTION HEATING OF GREENHOUSE

The traditional heating of greenhouses (based on liquid or air) lacks efficiency, when it concerns energy-saving or economic expenditures. The agricultural industry is therefore inter-ested in the innovative approach to the power supply of greenhouses. The use of geothermal sources, biofuel, heating pumps and other conventional greenhouse heating methods is not al-ways reasonable, as their application depends on location of an object, ecological factors and others. This research investigates a complex heating, when convection heating of the green-house territory is maintained by temperature using ceiling infrared radiators. The aim of the paper is to study the influence of the outdoor air temperature, thermal prop-erties of the perimeter walls and soil surface absorbing capacity on the heating power of a greenhouse within the proposed method of radiant and convection heating. A system of complex heatand material-balance equations is used to calculate the greenhouse perimeter walls and the soil surface. The research results show the dependency of the total heating power when calculated with regard to the outdoor temperature, heat resistance properties of the perimeter walls and the soil surface absorbing capacity. The results obtained can be used to justify the efficiency of the radiant and convection heat-ing of the greenhouse in specific climatic conditions. The scientific novelty of the paper is the proposed method of calculating which accounts of multiple heater reflection, the influence of the mass-exchange process inside the greenhouse as well as the absorbing soil properties.