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Torrefaction is considered as a method for producing biofuels with improved characteristics compared to those of the “raw” biomass (higher calorific value, moisture resistance, better grindability). The torrefaction process is an endothermic process that is usually carried out in a gaseous atmosphere in the absence of oxygen. To reduce the required heat input, it is proposed to employ the oxidative torrefaction and conduct the process in a fluidized bed agitated with flue gases containing less than 6% oxygen. Preliminary studies of the oxidative torrefaction of sunflower husks, including thermogravimetric analysis of the treated material, have shown that the heat treatment time for the biomass should be at least 5 min. A fluidized bed is a reactor with ideal mixing of the treated material where uniform treatment of raw material particles cannot generally be attained. To overcome this disadvantage of the fluidization technique and achieve the required residence time for biomass in a fluidized bed during a continuous torrefaction process, it was proposed to equip a torrefaction reactor with a series of vertical baffles spaced at 50 mm. These baffles induce a loop-like flow of the processed biomass from the inlet to the outlet of the reactor. To investigate the residence time for husk particles in the reactor, a tracer, which was colored to husk particles' color with a water-soluble dye which did not change the weight and size of the particles, was injected into the bed of uncolored particles. Tracer samples were taken every 30 s at the outlet of the reactor and were analyzed using a special procedure to determine the fraction of colored particles in each sample. This enabled us to gauge the time during which the colored particles injected into the fluidized bed reached the point of their discharge from the bed. Studies performed in a “cold” model of the reactor showed that a series of vertical baffles in the bed can provide the required residence time for biomass in a reactor including commercial reactors. Plates can provide the necessary biomass residence time in the reactor.

Using X-ray diffraction analysis, the effect of Ar+ ions with an energy of 15-20 keV (at ion current densities of 100-300 μA/cm2) on the microstructure, the level of internal microstresses and the texture of cold rolled ribbons of alloy Ni-13.9 wt.% W was studied. It was found that short-term irradiation of 80 μm thick ribbons with a fluence of 3.1·1016 cm-2 (for 50 s) at temperatures T ≤ 370°C and T = 630°C leads to a decrease in microstresses in their entire volume, but at the same time the original texture is retained. With an increase in the fluence to 9.7·1017 cm-2 at T = 630°C, the texture also changes from (220) to (200). Changes in microstresses and texture on the irradiated and unirradiated sides of 80-μm-thick ribbons are comparable to each other, despite the fact that the projective range of Ar+ ions with an energy of 15-20 keV in the alloy is only ~7 nm. It is known that annealing in an oven (700°C, 30 min) of such ribbons does not lead to their recrystallization. At 850°C, microstresses are relieved and the texture drastically changed from (220) to (200) both as a result of annealing in a furnace (15 s) and as a result of irradiation with a fluence of 3.2·1016 cm-2 for 17 s, but the effect removal of stresses in the course of furnace annealing is 3 times lower than in the course of irradiation. Thus, the following facts have been established: 1) the occurrence of recrystallization processes in the alloy under study during irradiation at a temperature lower than the temperature of the onset of thermally activated recrystallization and 2) a higher rate of microstresses drop (and to lower values) in the course of irradiation than during furnace annealing. This indicates a significant role of nanoscale radiation-dynamic effects at the cascade-forming irradiation of metastable media.

DATA AVAILABILITY : Data will be made available on request. ; Please read abstract in the article. ; http://www.elsevier.com/locate/seta ; 2024-09-30 ; hj2023 ; Mechanical and Aeronautical Engineering

The addition of ZnO, depleted in the Zn-64 isotope, to the water of boiling water nuclear reactors lessens the accumulation of Co-60 on the reactor interior surfaces, reduces radioactive wastes and increases the reactor service-life because of the inhibitory action of zinc on inter-granular stress corrosion cracking. To the same effect depleted zinc in the form of acetate dihydrate is used in pressurized water reactors. Gas centrifuge isotope separation method is applied for production of depleted zinc on the industrial scale. More than 20 years of depleted zinc application history demonstrates its benefits for reduction of NPP personnel radiation exposure and combating construction materials corrosion.

The rectification of uranium hexafluoride and its main technological impurities – tungsten and molybdenum hexafluorides – was studied. Irregular, fine, spiral, and spiral-prismatic packings were used as the separating elements. It is shown that the dependence of the working holdup of liquid metal-hexafluorides on the rectification parameters in a packing column with irregular fine packing is identical to the dependences given in the literature but with different coefficients and exponential factors.

The paper is concerned with the functional scheme and the basic equipment of a thermal station. Parameters requiring control in the continuous process of the heat transfer medium production and its delivery to the consumer are listed. The authors show the technological relationship between water heating conditions and the thermal station controlled electric drives providing the predetermined process conditions. Functional relations determining the balance of water flow and water pressure of the thermal station and the consumer as well as the relation of water flow and temperature of the hot water boiler are given. The functional scheme of control system for the thermal station output parameters and the block scheme of the local control systems of the heat and water balance are shown. The principles of process parameters control are justified.

Pyrrolyl and indolyl derivatives of azaaromatics have been prepared by an aerobic photo-induced oxidative C–H/C–H coupling method in the presence of nanosized TiO2.

Results of theoretical investigations into the dynamic drawing of powder materials through a narrowing conical die are presented. Curves are obtained for the change in density, and tangential and average normal stresses in polar-coordinate space. The results obtained are compared analytically with experimental data, and their satisfactory agreement is established.

Abstract The emission results from the diesel engine have a damaging effect on both the environment and people. Therefore, how to reduce and control these harmful exhaust emissions is mandatory requires plenty of experiments that elevate the cost and efforts. This paper depicts an application of an intelligent technique for prognostic the internal combustion of diesel engine performance, emission, and combustion characteristics. Zinc oxide (ZnO), aluminium oxide (Al2O3), and titanium oxide (TiO2) nanoparticles were added to diesel fuel. Experimental investigations were conducted on direct injection, water-cooled four cylinders, in-line, natural aspirated Fiat diesel engine. The engine was run at a firm speed of 1500 rpm with a regular fuel injection pressure at 400 bars but varying operation loads. Thus, the diesel engine emission and combustion characteristics, such as brake specific fuel consumption, thermal efficiency, carbon monoxide, unburned hydrocarbons, nitrogen oxide, and smoke concentrations were considered. The engine performance and exhaust gas analysis were conducted for seven various fuel blends and five load conditions. Therefore, in this current work, optimized ANN is utilised to model the relationship among engine emissions and operating parameters of direct injection diesel engines. The measured data was recorded for each conducted experiment to develop a multi-input multi-output intelligent system. Results obtained from the developed model were found to be suitable for predicting the engine performance and emissions for a limited number of available data and it was found to match well with those from the experiments.