ABSTRACT
A low-dissipation numerical method based on a combination of Godunov’s method and a piecewise parabolic method on a local stencil is presented. The construction of the method is described in ...detail. The method is tested using a one-dimensional problem of breakdown of a discontinuity. The results of a numerical simulation of collision of two relativistic gas spheres are given.
We describe the implementation of a modification of the Rusanov solver for the equations of special relativistic magnetic hydrodynamics. The particularity of the relativistic hydrodynamics equations, ...including a magnetic field, is a natural constraint on the admissible wave propagation velocity, which allows us to construct a fairly simple modification of the Rusanov solver using the maximum wave propagation velocity equal to the speed of light.
Venus' atomic hot oxygen environment Gröller, H.; Shematovich, V. I.; Lichtenegger, H. I. M. ...
Journal of Geophysical Research: Planets,
December 2010, Letnik:
115, Številka:
E12
Journal Article
Recenzirano
Odprti dostop
We present a Monte Carlo study of the atomic hot oxygen corona of Venus. In this model we consider elastic, inelastic, and quenching collisions between the traced hot particle and the ambient neutral ...atmosphere as well as differential cross sections to determine the scattering angle in the collisions. We also include rotational and vibrational excitation energies for the calculation of the initial energy of the produced hot oxygen atoms. Our results indicate that the differential cross sections and the fraction between elastic, inelastic, and quenching collisions are the most sensitive parameters which effect the corona density. We found that the hot O densities inferred from PVO observations can only be reproduced during high solar activity based on a forward scattering model but without inelastic and quenching collisions. The corona densities for low solar activity (VEX solar conditions) are about a factor of 2–3 smaller than for high solar activity.
Abstract
The process of bioconversion of the secondary product of pea flour processing into protein concentrate (serum) into fodder microbial-plant concentrate has been optimized. For this, a ...composition was selected from the culture of the fungus Geotrichium candidum 977 and the yeast Saccharamyces cerevisiae 121, a mathematical model of concentrate synthesis was developed in the form of an equation that adequately describes the dependence of the biomass yield on technological parameters: pH of the medium, temperature and amount of inoculum. The concentrate from the biomass had a protein mass fraction of 61.68 % of DS, from the biomass with the culture liquid - 57.90 %. Concentrates - biologically complete, the rate of essential amino acids was 107-226 %, out of 30 fatty acids, 97 % were acids that are part of animal fats, vegetable oils or marine organisms. The ratio of saturated and unsaturated acids is 1:3, the content of trans isomers is 5.1 %, omega-6 fatty acids (linoleic) is 19.73 %. The ability of symbiosis between the yeast S. cerevisiae 84/5 and the fungus Trich. cutaneum 656 has been proven. transform the components of whey remaining after the extraction of phytin from rice bran into protein biomass. The ratio of monocultures by mass fraction is 1:1, pH - 5.0…6.0, duration of growth - 72 hours, digestibility – 90 %. The protein is enriched with methionine, isoleucine, leucine, lysine. The amount of essential acids is 18-21 % higher than in concentrates obtained from individual monocultures. The use of concentrates is advisable to use in the diet of animals.
Introduction
. The novel coronavirus infection COVID-19 (NCI COVID-19) caused by the COVID-19 virus, which occurs in the most severe forms, is accompanied not only by the development of respiratory ...failure and acute respiratory distress syndrome, but also by other equally dangerous complications such as covid-associated coagulopathy.
The objective
was to study the clinical and laboratory features of the development of endothelial dysfunction as the main component of covid-associated coagulopathy in the context of its most common manifestation – thrombotic events.
Methods and materials.
The medical records of 947 patients with confirmed novel coronavirus infection COVID-19 hospitalized at the Center for the Treatment of Patients with NCI COVID-19 of Pavlov University of the Ministry of Health of the Russian Federation during the so-called «2nd wave» of the pandemic from November 2020 to March 2021.
Results
. All thrombotic complications were detected only in patients with severe coronavirus infection (561 patients). Predisposing factors for the development of thrombosis in our patients were: advanced age, duration of hospitalization for more than 1 week, comorbidity in the form of coronary artery disease. Standard screening tests of the hemostasis system (platelet microscopy, coagulogram screening) do not reveal any significant features in the presence of thrombotic events, which requires the development of new studies to assess prothrombotic potential in patients with severe NCI COVID-19.
Conclusion
. The development of thrombotic events is one of the most formidable complications in the severe course of NCI COVID-19, which in turn leads to an increase in respiratory failure due to increased tissue hypoxia, and subsequently to death. The same patients have an increased risk of hemorrhagic events as a possible side effect of the therapy.
We describe the implementation of a modification of the Rusanov solver for the equations of special relativistic magnetic hydrodynamics. The particularity of the relativistic hydrodynamics equations, ...including a magnetic field, is a natural constraint on the admissible wave propagation velocity, which allows us to construct a fairly simple modification of the Rusanov solver using the maximum wave propagation velocity equal to the speed of light.
In this paper, a new hydrodynamical code for the numerical simulation of the collision of the gas components of galaxies is described. The code is based on the Fluids-in-Cells method with the ...Godunov-type scheme at the Eulerian stage. Also, the velocity correction is employed at the Lagrangian stage and energy imbalance is minimized. The performance of the code is shown by the simulation of the collision of gas components of two similar disk galaxies in the course of the central collision of the galaxies in the polar direction. As a result of the numerical simulations within the model, we succeeded in determining the main scenarios of the collision of galaxies. At low velocities, both galaxies and their gas components coalesce. At high velocities, the massive stellar components of galaxies dissipate almost freely, leaving their gaseous components slowed down and heated by the collision. If the common gas component of the colliding galaxies cools down to the virial temperature, a new galaxy is formed from the two. With the high collision velocity, the gas component has no time to cool and therefore the gas dissipates in the intergalactic medium.
Pyrolysis of Coffee Husks and Parchment Zaichenko, V. M.; Knyazeva, M. I.; Krylova, A. Yu ...
Solid fuel chemistry,
2021/1, Letnik:
55, Številka:
1
Journal Article
Recenzirano
The pyrolysis of coffee husks and coffee parchment at 350 and 500°C was considered as the first stage of gasification by the two-stage thermal conversion of biomass into synthesis gas. The yields and ...compositions of pyrolysis products at the selected temperatures were determined. It was found that a significant amount of acetic acid was formed in the aqueous phase of the pyrogenic liquid to significantly complicate the use of an aqueous layer for the subsequent gasification. The possibility of practical implementation of the pyrolysis of waste coffee products as an independent process or the first stage of conversion into synthesis gas was noted.
A low-dissipation numerical method based on a combination of Godunov’s method and a piecewise parabolic method on a local stencil is presented. The construction of the method is described in detail. ...The method is tested using a one-dimensional problem of breakdown of a discontinuity. The results of a numerical simulation of collision of two relativistic gas spheres are given.
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