Current Issue : October-December Volume : 2021 Issue Number : 4 Articles : 5 Articles
The purpose of this work was to develop a Screened Hydrogenic Model (SHM) to accurately calculate the electron energies for light atoms and ions with up to ten electrons for atomic numbers up to 18. The total energy of an atom or ion was calculated with effective nuclear charges and screening parameters for each electron type (1s, 2s and 2p) within a specific electron configuration. Multiple energy states, centered at the total energy, were calculated for electron configurations that have Russell-Saunders coupling. The energy of each electron included its relativistic energy, EREL, but close overall agreement between the calculated and experimental energies of multi-electron configurations required that the one-electron expression for EREL be modified in a simple manner. In the present work, 98% of the 587 calculated energies for light atoms/ions have a relative error within ±0.1% of the corresponding experimental energies. The effective nuclear charges described in this work allow hydrogen-like wave functions to be defined for the electrons within a multi- electron configuration. The SHM, described in this work, is available for future calculations involving light atoms and ions....
Mixing of carbon dioxide dissolved in a multicomponent gas mixture at different pressures was researched. It was found that the mechanical equilibrium of the ternary gas mixture 0.4163H2 (1) + 0.5837CO2 (2) N2 (3) is violated at a pressure of p = 0.7 MPa and structured flows appear in the system. The pressure area (from 0.7 to 1.5 MPa) at which the conditions of priority transfer of components with the highest molecular weight in the mixture are realised in the system is fixed. To analyse the effect of pressure on the process of changing “diffusion–convection” modes, a mathematical model, which takes into account the kinetic features of multicomponent mixing, was applied. It was shown that the change in the modes of mass transfer is associated with a significant difference in the diffusion ability of the components. It is noted that the difference in the diffusion coefficients of components results in the nonlinearity of the concentration distribution, which leads to the inversion of the density gradient of the gas mixture, which is the cause of convective flows....
In order to study the separation characteristics of the aeroengine dynamic pressure oil-air separator, this paper uses the coupling method of PBM and CFD two-fluid model to study the influencing factors such as cylinder diameter, cylinder length, and other factors on the separator performance. *e flow field structure, velocity, gas volume distribution, separation efficiency, and gas and liquid holdup rate in the separator under different operating conditions are analyzed. Combined with the analysis results of the cylinder diameter and the cylinder length, the influence law of length-diameter ratio on separation efficiency is summarized. *e optimum length-to-diameter ratio that maximizes the separation performance of the separator is obtained in this research, which provides a reference for the design and improvement of the separator. *e results show that, as the diameter of the cylinder increases, the separation efficiency increases first and then decreases. When dsep � 16mm and dsep � 18 mm, the separator reaches its maximum efficiency, which is about 93%. With the increase of the cylinder length, the separation efficiency first increases and reaches the maximum when l2 � 90mm and then decreases slowly........
Long pulse-repetition intervals of 100 to 500 ms of a 193 nm ArF excimer laser successfully increased the height of the photochemical micro-/nano-swelling of silicone rubber, observed with a scanning electron microscope. The effect of the interval was seen despite the heating of the silicone rubber to 80 C during laser irradiation. The height of the micro-/nano-swelling was saturated when the laser pulse number was 300 or greater, although each of the saturated heights of the micro-/nano-swelling formed by several pulse-repetition intervals was different. Thus, a second ArF excimer laser irradiated the growing micro-/nano-swelling before the saturation; the saturated height of the growing micro-/nano-swelling could be controlled by the pulse-repetition interval of the second ArF excimer laser. To examine the process of micro-/nano-swelling, an early stage of the growth was observed using an atomic force microscope; a dent structure of the micro-/nano-swelling was clearly recognized. In addition, a needle-like structure of the micro-/nano-swelling could be formed when silica glass microspheres were sparsely aligned....
Biomass has the potential and benefits of being an alternative energy source to replace fossil fuels that exist today in Indonesia and other tropical countries. In addition, biomass has an abundant stock or supply. By assessing the feasibility of recovering potassium, it is hoped that more potassium resources and in future Indonesia will be dependent on imported fertilizers and increase the agricultural industry, which is the aims of this study. The best extraction result is using CH3COOH. Treatment of 1:10 solid-liquid ratio with the help of 1 mol/l CH3COOH was chosen as the best treatment because it is more economically efficient. Recovery of K with the help of tartaric acid and acetic acid resulted in a K recovery efficiency of around 94%. The optimal condition for the syngenite method is the addition of a magnesium dose of 5 mmol/l and at pH 11, the Ca: K ratio is 1:2.1 with 42% K. This can be a suggestion which method is more effective and efficient in recovery K....
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