Specific Energy Consumption Values Research Articles

Effluents from the copper electrorefining as a secondary source of antimony: Role of mass transfer on the recovery by electrodeposition

The limited availability of antimony has increased the need for exploiting alternative sources to its direct extraction from stibnite deposits. Furthermore, introducing recovery techniques in industries where antimony is released in wastewaters leads to more responsible production routes. In this work, electrodeposition is employed to recover the antimony present in a secondary waste effluent of the copper electrorefining that is highly concentrated in hydrochloric acid. The electrochemical characterization of the system was conducted by voltammetry to identify a range of suitable operating conditions for the potentiostatic and galvanostatic electro-recovery of antimony. In potentiostatic mode, the progress of the secondary electrode reactions of hydrogen and chlorine evolution at potentials more cathodic than −0.38 V vs. Ag/AgCl causes the detachment and redissolution of the deposited antimony. Operating under galvanostatic control, similar effects were observed when the limiting current density is exceeded. Current efficiency and specific energy consumption values above 50 % and below 65 kW·h·kg−1, were achieved below the limiting current density (1.265 mA·cm−2). The operational range where electrodeposition of antimony is accelerated at increasing current densities can be broadened at intensified hydrodynamic conditions and higher concentrations of antimony. The detrimental effect of the hydrogen evolution reaction on the recovery of antimony decreases at high HCl concentrations.

A methodological framework to benchmark and monitor energy performance in textile wet processing small and medium enterprises: Proposal and evaluation

The customers of textile wet processing plants have committed to reduce their greenhouse gas emissions from outsourced manufacturing activities. The textile brands directly use specific energy consumption values to analyze and set steep, time-bound emission intensity reduction targets for the energy intensive textile wet processing plants. However, the direct use of specific energy consumption values to evaluate energy savings can be misleading. In this paper, the authors propose a methodological framework to systematically evaluate energy performance and monitor energy savings in the textile wet processing plants. Further, the approach was extended to analyze the energy performance monitoring practices and identify energy conservation measures. The proposed framework was developed based on thorough analysis of the manufacturing process of textile wet processing plants and the principles of ISO 50001. A textile wet processing plant was chosen as a case study for illustrating the effectiveness of the framework using multiple regression method. Bottom up approach for benchmarking was used and yet significantly simplified by the introduction of an innovative parameter “program mix factor” and thereby evaluate “equivalent specific energy consumption”. The predicted values for specific energy consumption were found to be within a close error range of ±10 % of the actual data. The proposed methodological framework is therefore innovative, simple and yet comprehensive to conduct internal benchmarking in textile wet processing plants. The textile brands are suggested to use equivalent specific energy consumption instead of specific energy consumption for energy performance monitoring of their textile wet processing plant suppliers. The authors also conducted a survey in fifteen textile wet processing plants to assess the prevailing energy monitoring practices. The results of the survey suggests that only 20 % of the plants are practicing basic level energy performance monitoring, while the remaining 80 % are at minimal level.

Recovery of Methanol during Natural Gas Dehydration Using Polymeric Membranes: Modeling of the Process.

A significant proportion of natural gas (NG) is produced in cold climates, where conditions are relevant to the formation of gas hydrates in raw gas stream. Methanol is often used as an effective inhibitor of hydrate formation. Further conditioning of NG includes dehydration, and the most common process of water vapor removal from NG is absorption. Absorption also provides removal of methanol vapors, which allows it reuse. The membrane method of natural gas dehydration is considered as a promising alternative; however, the study of methanol recovery by the membrane method, simultaneously to the dehydration of NG, has not been carried out previously. In addition, data on methanol vapor transfer in gas separation polymer membranes are almost absent in the literature. This paper evaluates the permeability coefficients of methanol vapors for several polymer materials, which are applied to the production of industrial membranes (PPO, PSf, CA). Mathematical modeling of the membrane process of NG dehydration with simultaneous recovery of methanol was performed. The dependencies of membrane area, methanol recovery and energy consumption for methane recycling and recompression on the process parameters are calculated. Obtained data show that the recovery of methanol during membrane dehydration of NG varies in the range 57-95%. The lowest values of membrane area and specific energy consumption were found for PPO based membrane.

Treatment of wastewater from the washing process of a municipal solid waste collection container by electrochemical treatment using different anode materials: a statistical optimization.

An underground municipal solid waste (MSW) container should be washed periodically to prevent/reduce odor and leachate production. In this study, the treatment process of wastewater derived from the washing process of an MSW container was investigated using the electrochemical (EC) treatment process with different anode materials (Fe, TiO2, and graphite). Response surface methodology (RSM) was used to evaluate the effect of process parameters such as initial pH, applied current, and reaction time on chemical oxygen demand (COD), Tannin/Lignin, and color removals. According to the results obtained from the RSM models, all process parameters were significant. The optimum process parameters in terms of COD removal were derived from the models for each anode material. Under the optimized conditions, the COD removals were determined to be 93.25%, 75.95%, and 98.46% for Fe-Fe, TiO2-Fe, and graphite-Fe electrode pairs, respectively. The color and Tannin/Lignin removals were determined as 98.12% and 77.78% for the Fe-Fe, 92.76% and 98.45% for the TiO2-Fe and 94.50% and 79.56% for the graphite-Fe electrode pair, respectively. The specific energy consumption (SEC) values were found as 46.95, 300.02, and 32.95 kWh/m3 for each electrode combination given above, respectively. In terms of both removal efficiencies and SEC, the most effective anode material was determined as graphite, followed by iron.

Structural performance of alkali/acid‐ultrasound modified Agave fibers during the melt mixing process with polyvinyl alcohol

AbstractThis study aims to investigate changes in the structural properties of alkali/acid‐ultrasound modified Agave fibers and their performance immersed on a polyvinyl alcohol (PVA) matrix with plasticizer during melt mixing processing. Structural analysis revealed that ultrasound enhances the effectiveness of the conventional alkaline/acid treatments to modify fibers since the simultaneous treatment increased the partial removal of lignocellulosic components, water molecules, and amorphous regions which improved their processability on a PVA matrix. Specific energy consumption values indicated that during melt mixing the modified fibers required more energy to expose the chains of cellulose fraction to function as an interaction site for PVA chains. Once the mixture was homogenized, the fiber‐matrix interactions promoted high viscosity, friction, and mechanical stress in the chamber. Therefore, the modified fibers restricted the interaction between plasticizer and PVA in the obtained films, resulting in a highly structured, and reinforced network, increasing the storage modulus as dynamic mechanical analysis indicated. These findings highlight a feasible way to valorize Agave fibers and allow the understanding of the matrix‐fiber interactions during melt mixing processing, useful to predict the structural and mechanical properties of the films.

Interaction of Different Drying Methods and Storage on Appearance, Surface Structure, Energy, and Quality of Berberis vulgaris var. asperma.

Seedless barberry fruit is native small fruit in Iran. To examine the impact of various drying methods and storage on the biochemical attributes (Vitamin C, Anthocyanin, Phenol, pH, TA), color index (a*, b*, L*, ab, and Chroma), drying time, and fruit microstructure (by SEM) of seedless barberry (Berberis vulgaris var. asperma), and effective moisture diffusivity coefficient (Deff), specific energy consumption (SEC), energy efficiency (EE) of the dryers, this experiment was performed. Drying treatments include microwave (100, 170, and 270 W), oven (60 and 70 °C), cabinet (50 and 70 °C), shade, sun, and fresh samples (control) and storage 6 months after drying (in polyethylene packaging and at a temperature of 5–10 °C). Results showed minimum and maximum drying times (50 min and 696 h), were related to microwave (270 W) and shade methods, respectively. The highest color values were observed in fruits treated with control, shade and sun treatments and the lowest values were observed in cabinet (70 °C) methods. According to the SEM results, microwave significantly affected surface structure of the dried sample compared to others. The findings indicated that the use of artificial drying methods than natural methods (sun and shade) cause a more significant reduction in color indexes, while vitamin C, soluble solids, and anthocyanin were significantly maintained at a high level. Storage reduced anthocyanin content of fruits almost 12%. Moreover, it was discovered EE and SEC values varied in the range of 1.16–25.26% and 12.20–1182 MJ/kg, respectively. Deff values were higher in microwave 270 W.

Evaluation of low energy consumption control for seawater desalination on Penghu Island

In fact, current water supplies due to natural constraints or lack of infrastructure (or both) cannot be provided in a sustainable manner for all increasing and competing uses (e.g. residential, industrial, agricultural). While promoting Penghu's low-carbon islands, in a water-scarce environment, it is the motivation of this research to take into account the development of water resources and lower energy consumption costs. The seawater desalination plant water production technology is improved, the cost of water production is reduced. This research uses a genetic algorithm (GA) to optimize the recovery rate to solve the minimum Specific energy consumption (SEC) value, and then, according to the required water production, the optimal flow rate of raw seawater of the high-pressure pump is obtained, so as to minimize the energy consumption of the reverse osmosis (RO) system. The energy recovery device has a great effect on reducing the energy consumption of the RO system, and it can be seen from the results that the higher efficiency does greatly reduce the energy consumption of the SEC and water production under the different energy recovery device efficiency. Calculated using genetic algorithms, and the SEC is 3.275 and the recovery rate is 45.1%, and the water production energy consumption is 2.35 kWh/m3. Scheme B changed the efficiency of the energy recovery unit to 97.22%, resulting in a SEC of 1.819 and a recovery rate of 25.3%, and a water production energy consumption of 1.31 kWh/m3. Finally, challenges and research gaps are also proposed.

The concept of quasi-brittle rock fracture as applied to extraction and processing operations

Research objective is to substantiate the method for calculating the value of specific surface energy as the work irreversibly expended on fracture surfaces formation in the course of rock fracture in mining flow processes. Methods of research. The scheme of a uniformly expanded thin brittle plate with an embedded crack perpendicular to the load (Griffith plate) was taken as the basis for analytical calculations. The statement of the problem was based on building the energy balance of the work irreversibly expended on fracture surfaces formation through crack creation and propagation. The general solution analysis revealed that the well-known Griffith formula refers to a particular case of a perfectly brittle material fracture, when a sample in the form of a plate has specific dimensions with respect to the length of the embedded crack. Griffith theory postulates the presence of embedded structural cracks in a fractured body and does not explain the mechanism of crack creation and propagation up to the critical value. Therefore, it has not yet found practical application in analytical calculations of mining operations. Results. To extend application of the obtained design dependence of the specific surface energy for the tough fracture of rocks as well, a modified Irwin criterion has been proposed that determines the condition for the local fracture of crack-like flaws in the material’s structure. Therefore, by introducing a new constant in the form of an integrated structural-textural constant of the rock material, it has become possible to obtain the final answer to the question of what the value of specific energy consumption is in the flow processes of rock fracture by tensile cracks propagation. The theoretical novelty of the obtained regularity, along with its clear, understandable physical sense, is represented in the specific energy irreversibly spent for through tensile cracks creation by substantiated introduction of energy efficiency in the course of fracture, which substantially increases the value of the design energy consumption.

SURFACE TEMPERATURE PROFILE, ENERGY-EXERGY ANALYSES AND THERMO-PHYSICAL PROPERTIES OF POTATO CHIPS DRIED IN MICROWAVE AND HYBRID (MICROWAVE + CONVECTIVE) OVENS

The present study potato slices were dried at a microwave oven and hybrid (microwave + convective) oven at PR 3 power rate. Effects of drying methods and conditions on surface temperature profile, drying characteristics, effective diffusion, activation energy, thin-layer drying model, specific moisture extraction rate (SMER), specific energy consumption (SEC), energy efficiency (EE), specific exergy loss (SEL), exergy efficiency (EXE), specific heat, thermal diffusivity, thermal conductivity and density were investigated. The lowest surface temperature (39.00 ºC) was observed in 160 W+55 ºC drying treatment and the greatest (128.30 ºC) in 160 W+75 ºC drying treatment. Among the thin-layer drying models, Wang-Sing model was identified as the best model. Effective diffusion values of drying treatments varied between 1.14x10-7- 3.18x10-10, activation energy values between 79.12 kJ/mol (Microwave) and 126.96 kJ/mol (microwave + convective), SMER values between 1006.57 - 1950.14 kg water/kWh, SEC values between 8.86 - 14.31 MJ/kg water, EE values between 2.55 - 19.39%, SEL values between 0.42 - 12.68 kJ/kg. Of thermophysical properties of potato slices, specific heat values varied between 837.69 - 848.13 J/kgºK, thermal conductivity values between 0.07 - 0.27 W/mºK, thermal diffusivity values between 1.163 - 3.774x10-6 m2/s and density values between 700.60 - 839.41 kg/m3.

Enhancing the performance of a greenhouse drying system by using triple-flow solar air collector with nano-enhanced absorber coating

In this research, the impacts of utilizing nano-embedded absorber coating in an auxiliary heater of a greenhouse drying system on the thermal and drying performances have been surveyed empirically. In this context, triple-flow solar air collectors with and without CuO nano-enhanced absorber coating have been designed and manufactured. Designed collectors then integrated to even-span greenhouse dryers to be used as an auxiliary heating device. In the experiments, greenhouse dryers have been tested with and without auxiliary heaters at constant flow rate which is 0.014 kg s−1. According to the experimental findings, utilizing triple-flow solar air heating device with and without nano-embedded paint decreased the drying time as 35.71% and 26.66%, respectively. Thermal and exergetic efficiencies for newly developed collectors were found between the range of 70.39–75.11% and 9.05–10.18%, respectively. In addition, specific energy consumption values were decreased by using collectors with and without nano-enhanced modification from 2.51 to 2.11 and from 2.61 to 2.18 kWh/kg, respectively. Attained outcomes of this study showed the successful utilization of nano-enhanced absorber coating in the auxiliary heating system of the greenhouse dryer.

Water vapor desorption from silica gel in a combined drying and double-condenser compression refrigeration system

The drying method requires an effort to store food for a longer time. Some drying processes experience technical and economic weaknesses, mainly related to low efficiency, high energy costs, and decreased product quality. Various drying models have been studied to determine the suitability of heat and mass transfer analysis at drying rates in an air dehumidification scheme using different materials, one of which is silica gel. In this case, the researchers examined the effects of humidity, temperature, and airflow rate on the constant drying rate and activation energy of water desorption in silica gel using a packed bed dryer that was modified with a refrigeration system. This modified system aims to reduce specific energy consumption (SEC). The results demonstrate that the constant rate of water desorption in silica gel and the increase in air humidity cause a decrease in the constant value of the water desorption rate in silica gel. However, increases in the temperature and airflow cause an increase in the value of the constant drying rate for water desorption in silica gel, as they cause capillary evaporation. Meanwhile, the activation energy of water desorption in silica gel increases with decreasing air flow rate and increasing inlet air humidity. The attractive force acting on the water molecules from the surface force field on the surrounding walls becomes stronger if the air flow rate decreases or the air humidity increases. From the results and analysis, it is shown that the activation energy of water desorption in silica gel with significant air humidity and low flow rate, of 0.013 kg/kg d.a. (450 lpm), is the highest at 35.16 kJ/mol, whereas in silica gel with air humidity of 0.007 kg/kg d.a. (750 lpm), it is the lowest at 22.92 kJ/mol. Meanwhile, the dryer air flow rate, higher heater temperature, and lower air humidity improve the performance of the bed dryer against its evaporation rate and decrease the Specific Energy Consumption (SEC) value. SEC is also greatly influenced by the use condenser 1, which provides heater power savings of up to 79.1%. Thus, the system is expected to be applied to commercial drying systems that can work at low drying temperatures to maintain drying products and obtain low energy consumption.

Boron removal by using vacuum assisted air gap membrane distillation (VAGMD)

Vacuum-assisted air gap membrane distillation was used to remove boron from different waters in this study. Four different vacuum pressures (0.02 bar, 0.04 bar, 0.06 bar, and 0.08 bar) were applied and air gap membrane distillation (AGMD) configuration was also used to compare the effect of vacuum pressures on the process. Six commercial hydrophobic membranes which have the 110° contact angle value at least were used. Membranes with a 44.18 cm 2 effective area were tested with saline water, synthetic boron solution, and real geothermal water as the feed solutions which is the only study with VAGMD in the literature. Salt removal efficiencies of all experiments were higher than 98.2%. Permeate boron concentrations of synthetic boron solution and real geothermal water were lower than the 0.5 mg/L limit value for drinking water set by WHO and in terms of removal efficiency it means higher than 99% removal efficiency. Vacuum pressures enhanced the water fluxes as expected and also decreased the specific energy consumption. • The use of a supplementary vacuum pump on the AGMD system improved the flux. • Increasing pressures increase flux and GOR without any considerable rejection loss. • Higher than 99% boron removal efficiencies were achieved. • All permeate boron concentrations were obtained below 0.5 mg/L. • Specific energy consumption values did not increase although using a vacuum pump.

Experimental study on design and operational performance of solar-powered venturi aeration system developed for aquaculture – A semi-floating prototype

Venturi-type injectors have been used usually due to the practical use and modular design that allows for quick configuration, ready-to-use, and low-cost solutions in the last years. This study aims to design a solar-powered venturi aeration system (SVAS) and determine its flow characteristics, standard, and real-time operational performance parameters. SVAS has a design providing the maximum vacuum and air velocity at air inlets and allowing for all technical measurements. Moreover, a solar-powered experimental apparatus having a weather station, a pool station, and a data logger station was constructed. Experiments were carried out using a plastic pool with a capacity of 4000 L, a diameter of 3 m and a depth of 0.75 m, four venturi injectors, and a submersible pump of 0.3 kW operated at the constant water flow regime of 4.1 m3 h-1. According to flow tests, the oxygen mass flow rates ranged from 2.77 to 2.84 kg h−1. The specific energy consumption values are 263.2 kJ per cubic meter for water flow and 380 kJ per kg for oxygen transfer.Standard performance experiments were repeated four times. The maximum overall oxygen mass transfer coefficient obtained during the experiments was 5.58 h−1. The maximum values of standard oxygen transfer rate (SOTR), standard aeration efficiency (SAE), and standard oxygen transfer efficiency (SOTE) were 0.206 kgO2 h−1, 0.681 kgO2 kWh−1, and 7.32%, respectively. The pool conditions were simulated using de-oxygenation and mixing systems to determine the operational performance. For simulation experiments, six procedures and two processes were applied. Throughout operational experiments of four days, real-time dissolved oxygen levels fluctuated between 1.05 mg L−1 and 6.65 mg L−1. The maximum performance values were 0.143 kgO2 h−1 for the actual oxygen-transfer rate, 0.474 kgO2 kWh−1 for aeration efficiency, and 5.1% for oxygen transfer efficiency.

Evaluation of the Specific Energy Consumption of Sea Water Reverse Osmosis Integrated with Membrane Distillation and Pressure-Retarded Osmosis Processes with Theoretical Models.

In this study, theoretical models for specific energy consumption (SEC) were established for water recovery in different integrated processes, such as RO-PRO, RO-MD and RO-MD-PRO. Our models can evaluate SEC under different water recovery conditions and for various proportions of supplied waste heat. Simulation results showed that SEC in RO increases with the water recovery rate when the rate is greater than 30%. For the RO-PRO process, the SEC also increases with the water recovery rate when the rate is higher than 38%, but an opposite trend can be observed at lower water recovery rates. If sufficient waste heat is available as the heat source for MD, the integration of MD with the RO or RO-PRO process can significantly reduce SEC. If the total water recovery rate is 50% and MD accounts for 10% of the recovery when sufficient waste heat is available, the SEC values of RO, RO-PRO, RO-MD and RO-MD-PRO are found to be 2.28, 1.47, 1.75 and 0.67 kWh/m3, respectively. These critical analyses provide a road map for the future development of process integration for desalination.

Degradation of carbendazim in aqueous solution by different settings of photochemical and electrochemical oxidation processes

The present study analyzed the performance of photochemical and electrochemical techniques in the degradation and mineralization of the pesticide carbendazim (CBZ). Direct photolysis (DP), heterogeneous photocatalysis (HP), photoelectrocatalysis (PEC), and electrochemical oxidation (EO) were tested, and the influence of UV radiation, current density (j), and supporting electrolyte concentration were evaluated. The results suggest that CBZ is only degraded by DP when UV-C254nm is used. For HP, the CBZ degradation was observed both when UV-A365nm or UV-C254nm were used, which is related to the reactive oxygen species (ROS) formed by the photocatalytic activity (photon-ROS). Neither DP nor HP were able to mineralize CBZ, demonstrating its resistance to photomediated processes. For EO, regardless of the j, there were higher CBZ degradation and mineralization than those observed when using DP and HP. The increase in the supporting electrolyte concentration (Na2SO4) did not affect the levels of degradation and mineralization of CBZ. Concerning the PEC, a CBZ mineralization of 52.2% was accomplished. These findings demonstrate that the EO is the main pathway for CBZ mineralization, suggesting an additional effect of the electro-ROS on the photon-ROS and UV-C254nm. The values of mineralization, kinetics, and half-life show that PEC UV-C254nm with a j of 15 mA cm−2 was the best setting for the degradation and mineralization of CBZ. However, when the values of specific energy consumption were considered for industrial applications, the use of EO with a j of 3 mA cm−2 and 4 g L−1 of Na2SO2 becomes more attractive. The assessment of by-products formed after this best cost-efficient treatment setting revealed the presence of aromatic and aliphatic compounds from CBZ degradation. Acute phytotoxicity results showed that the presence of sodium sulfate can be a representative factor regarding the toxicity of samples treated in electrochemical systems.

Combination of germination and innovative microwave-assisted infrared drying of lentils: effect of physicochemical properties of different varieties on water uptake, germination, and drying kinetics

Soaking, germination, and thermal processing of lentils are common treatments to improve the functional and nutritional properties and expand its usage as an affordable plant-based protein in other food applications. In this work, combinations of these procedures have been studied by investigating the hydration, germination, and dehydration behavior of three commercial varieties of lentils; Maxim, Imvincible, and Greenland, with respect to the effect of their physicochemical and mechanical properties on these behaviors. The novel and efficient microwave-assisted infrared heating has been employed for dehydration, and drying kinetics were evaluated by fitting various thin-layer models. For this reason, lentil seeds were soaked for 16 hours, germinated for the duration of 1, 2, and 3 days, and thermally processed at 0.14, 0.42, and 0.7 kW microwave power, and 0, 0.375, and 0.75 kW infrared power. The results revealed that Greenland had the highest water uptake (110.89 g of water/100 g of seeds) due to its larger size, higher bulk porosity, and less fat content. This higher water uptake by Greenland leads to a more significant drop in its bio yield force after soaking. Furthermore, the diffusion approach model was the best equation to describe the microwave-infrared drying process of all the varieties. Microwave power had the most impact on drying rate, followed by infrared power, while the effect of germination time was not significant. The value of specific energy consumption varies by microwave and infrared powers and has the least amount for microwave power of 0.42 kW and infrared power of 0.375 kW.

Формування оптимальних енергетичних та теплотехнічних характеристик огороджувальних конструкцій будівель

The purpose of the work is to study of options for thermal modernization of enclosing structures with a justification of the optimal composition of energy-saving measures to achieve maximum energy efficiency of buildings. Ukraine's energy balance shows that more than 30% of the total energy is consumed by the residential sector, of which up to 80% goes to heating. This is due to the low level of energy efficiency of the enclosing structures of residential buildings, as well as the unsatisfactory technical condition of utilities, due to physical wear and tear and obsolescence. The peculiarities of the influence of the type of thermal insulation materials and their characteristics on the thermal and energy performance of the building are investigated. It was found that the increase in the density of insulation affects the thermal resistance of walls in different ways - the density of mineral wool and extruded polystyrene have the opposite effect of foamed polystyrene, ie insulation of mineral wool or extruded polystyrene should be chosen with the lowest density Element-by-element analysis of the components of enclosing structures proved that their impact differs significantly, in the case of separate implementation of measures can reduce heat consumption by 0.07… 23%, and the priority is to modernize the walls of building facades (provided that the glazing ratio K ≤ 0 , 25). Measures of complex thermal modernization of enclosing structures are substantiated by the method of expert assessments according to technical-energy, financial and ecological criteria. Calculations confirm that the complex thermal modernization will reduce the value of specific energy consumption and specific greenhouse gas emissions by 1.5 times, specific heat consumption - by 1.9 times, increase the energy efficiency class of the building from G to D. It is shown that the normative values of heat transfer resistances of external enclosing structures will provide only the class D energy efficiency of the building. It is not possible to achieve the recommended class "C" and higher by further increasing the thermal resistance of the enclosing structures - it is necessary to modernize the engineering systems of the building.

ВЛИЯНИЕ КРУПНОГО ЗАПОЛНИТЕЛЯ НА ЭНЕРГЕТИЧЕСКИЕ И СИЛОВЫЕ ХАРАКТЕРИСТИКИ СТАЛЕФИБРОБЕТОНА

At present, composite materials are gaining more and more development in construction, including the use of dispersed reinforced concrete, which is due to its significantly improved physical, mechanical and operational characteristics compared to traditional concrete and reinforced concrete. The article presents the results of the influence of coarse filler in the composition of the composite on the energy and power characteristics of the crack resistance of fiber-reinforced concrete reinforced with steel anchor fibers. The process of deformation and the mechanism of destruction of steel fiber reinforced concrete have been studied. To do this, in accordance with the provisions of GOST 29167 "Methods for determining the characteristics of crack resistance (fracture toughness) under static loading", steel-fiber-reinforced concrete sample beams were tested with control of the applied load and the deflection caused by it. Based on the data obtained, diagrams of the dependence of the load on the deflection were constructed, after their processing and additional constructions, the energy costs for static destruction, tensile strength in bending, and the stress intensity factor were determined. It has been established that the value of the conditional specific effective energy consumption for static failure and tensile strength in bending of fiber-reinforced concrete samples with a matrix of heavy concrete with coarse aggregate turned out to be lower than that of fiber-reinforced concrete samples with a matrix of fine-grained concrete, which is explained by the lower adhesion of the steel anchor fiber to the matrix, and a corresponding decrease in their efficiency.

Effect of Drying Temperature on Drying Characteristics, Total Phenolic Content and Antioxidant Activity of Slightly Sticky Mango (Mangifera Indica L.) Sheet

Dried slightly sticky mango sheets is healthy sweet snack, having slightly chewy texture. The objective of this work was to study the effect of drying temperatures (60, 70 and 80 °C) on the drying characteristics, total phenolic content (TPC), antioxidant activity (assessed by DPPH and ABTS scavenging activity assays) and specific energy consumption of the dried slightly sticky mango sheets. The experimental results showed that the times required to reach the desired final moisture content were 230, 150 and 120 min when drying was performed at the temperatures of 60, 70 and 80 °C, respectively. The total specific energy consumption (SECtotal) values of the drying at 70 and 80 °C were lower than that at 60 °C. However, the TPC and the antioxidant activities assessed by DPPH and ABTS scavenging activity assays were not significantly different amongst the samples dried at different temperatures.

Study of steam methane reforming in plasma generated by nanosecond surface gas discharge

The paper represents the results of the experimental study of steam methane reforming under the action of spark discharge on water surface. Values of conversion rate and output of reaction products at methane pressures of 1 to 5 atm were obtained, and specific energy consumption of reforming process was determined. Pulse generator with a voltage amplitude up to 200 kV and a pulse duration of 15 ns was used to power the discharge. Although an increase in pressure decreases both the methane conversion rate and the energy deposition into the gas mixture, the conversion efficiency and specific energy consumption remain the same. The obtained minimum value of specific energy consumption for steam methane reforming amounted to 10 eV/molecule.