Liquid spreading in trickle-bed reactors: Experiments and numerical simulations using Eulerian--Eulerian two-fluid approach

Liquid spreading in gas-liquid concurrent trickle-bed reactors is simulated using an Eulerian twofluid CFD approach. In order to propose a model that describes exhaustively all interaction forces acting on each fluid phase with an emphasis on dispersion mechanisms, a discussion of closure laws available in the literature is proposed. Liquid dispersion is recognized to result from two main mechanisms: capillary and mechanical (Attou and Ferschneider, 2000; Lappalainen et al., 2009- The proposed model is then implemented in two trickle-bed configurations matching with two experimental set ups: In the first configuration, simulations on a 2D axisymmetric geometry are considered and the model is validated upon a new set of experimental data. Overall pressure drop and liquid distribution obtained from $\gamma$-ray tomography are provided for different geometrical and operating conditions. In the second configuration, a 3D simulation is considered and the model is compared to experimental liquid flux patterns at the bed outlet. A sensitivity analysis of liquid spreading to bed geometrical characteristics (void-fraction and particles diameter) as well as to gas and liquid flow rates is proposed. The model is shown to achieve very good agreement with experimental data and to predict, accurately, tendencies of liquid spreading for various geometrical bed characteristics and/or phases flow-rates

The Rotating Gliding Discharge in Quartz Tube and Open Half-Space at Atmospheric Pressure

Rotating sliding discharge (RGD) was investigated into limited volume and open half-space. The cur-rent-voltage characteristics of the discharge and its specifications are described. The results of optical research: photos and emission spectra of the discharge are presented

Numerical simulations of 3D flows with moving contact lines

Flows with moving contact lines are encountered in many applications involving wetting phenomena such acid gas treatment with contacting devices, film coatings, and microfluidics. Numerically simulating flows with moving contact lines under realistic conditions is a computational challenge, because a large range of length scales is involved, and the fluid/fluid interface is generally strongly curved close to the contact line. This is due to the different physical behavior in the near vicinity of a moving contact line: a conventional no-slip formulation would lead to a singularity in the wall stress at a moving contact line. Several models have been proposed to account for the physical behavior in the near vicinity of contact lines ? herein we adopt a slip formulation, which involves a slip length parameter that is typically estimated to be nanometric, which is much smaller than the dimensions of an entire flow, even for a millimetric droplet. Direct numerical simulations (DNS) of such flows wherein the entire flow is resolved not being feasible, it is proposed here to numerically resolve the large-scale flow and part of the intermediate-scale flow whilst using a subgrid-scale model, which originates from hydrodynamic theories, to represent the unresolved part of the flow. We have developed a methodology for such large-scale simulations in 3D in the context of level-set methods. Results will be presented first for axisymmetric droplet spreading (simulated in 3D) in a regime dominated by viscous and capillary effects, with a comparison against results of DNS available in the literature. This is followed by results for axisymmetric droplet spreading (simulated in 3D) for more rapid flows, wherein inertial effects enter the contact-line region, for which excellent agreement with experimental data was obtained, both qualitatively and quantitatively. A second part of the work investigates whether such a model can be used for more complex evolution of contact lines, including effects of contact-angle hysteresis in 3D, which are also represented by our computational method. For this purpose, we consider next three-dimensional drops sliding down an inclined plane; numerical results will be demonstrated to be in good agreement with experiments. The subgrid-scale model used herein is restricted to flows with moving contact lines on planar substrates with small gravity effects compared to capillary effects. Further complexities may now be considered, involving heterogeneous substrates or higher Bond numbers, which calls for further DNS and theoretical development

Human Health Exposure to Adverse Environmental Impact in the Khabarovsk Kray of Russia

The authors analyze harmful environmental impact of both natural and technical factors on human health. While describing the Khabarovsk Kray geographic, climate, flora and fauna peculiarities they demonstrate that the main ecological factors affecting people's health are general pollution, air pollution and poor quality of drinking water, especially in large populated areas leading to a high morbidity of 137,193.4 cases per 100,000 people. Forest fire rate in the territory of the Kray is Russia's highest. Raising the level of ecological awareness and making the public to partake in solution of environmental problems are among the efforts to be made to improve the situation. Medical nurses of the Khabarovsk Kray have always been contributing to the improvement of the environment through population education in healthy lifestyle and accurate and careful attitude to nature and our habitat

Straintronics in Phosphorene: Tensile vs Shear Strains and Their Combinations for Manipulating the Band Gap

We study the effects of the uniaxial tensile strain and shear deformation as well as their combinations on the electronic properties of single-layer black phosphorene. The evolutions of the strain-dependent band gap are obtained using the numerical calculations within the tight-binding (TB) model as well as the first-principles (DFT) simulations and compared with previous findings. The TB-model-based findings show that the band gap of the strain-free phosphorene agrees with the experimental value and linearly depends on both stretching and shearing: increases (decreases) as the stretching increases (decreases), whereas gradually decreases with increasing the shear. A linear dependence is less or more similar as compared to that obtained from the ab initio simulations for shear strain, however disagrees with a non-monotonic behaviour from the DFT-based calculations for tensile strain. Possible reasons for the discrepancy are discussed. In case of a combined deformation, when both strain types (tensile/compression + shear) are loaded simultaneously, their mutual influence extends the realizable band gap range: from zero up to the values respective to the wide-band-gap semiconductors. At a switched-on combined strain, the semiconductor-semimetal phase transition in the phosphorene is reachable at a weaker (strictly non-destructive) strain, which contributes to progress in fundamental and breakthroughs.Comment: 16 pages,5 figures, 1 tabl

Dynamics of infectious and parasitogenic morbidity at the children population in the rural districts and corelation with water factor

Introduction: Intestinal parasites are important enteric pathogens. Poverty, low quality of food and water supply and poor sanitation systems are the important factors associated with intestinal parasitic infections. These kinds of infections can be a good index for hygienic and sanitation status of the society. The aim: To study dynamics of infectious and parasitic diseases (for 2008-2013 years) among the children population in Dnipro region and to define influence of water factor on the disease and prevalence given class of illnesses. Materials and methods: Retrospective study of infectious and parasitogenic diseases (І class by ICD-10) among children population from rural districts of Dnipropetrovsk region for 2008-2013 years was carried out. Results: It was spent correlation analysis between some indicators of potable water quality of diseases of the given class in all districts. In the majority of rural districts, was shown increasing І class of diseases from (1.4 to 1.63) times in dynamics. In some districts was reveled an average correlation link between content in water of the dry residue, chlorides, sulphates, calcium, magnesium, except rigidity and iron and prevalence І class of diseases (r=0.50, p<0.001). Prevalence of the given class of diseases was correlated with рН, nitrates, oxidability in the three rural districts of Dnipropetrovsk region (r=0.74-0.89, p<0.001). Conclusions: It has been shown that the composition of drinking water consumed by the rural population remains one of the basic factors in the formation of public health in the conditions of small exposure of the influence individual indicators of salt and chemical composition. The children’s cohorts were the most sensitive to these indicators

Plasma-liquid system with rotational gliding discharge with liquid electrode

Plasma-liquid system based on rotational gliding discharge with one liquid electrode was developed. Emission spectra of plasma of rotational gliding discharge with one liquid electrode were investigated. Discovered effective mechanism of controlling non-isothermal level of plasma in dynamic plasma-liquid systems. Major mechanism of expulsion of metal anode material from plasma-liquid systems with rotational discharges was shown.Разработана плазменно-жидкостная система, в основе которой лежит вращательный скользящий разряд с одним жидким электродом. Исследованы спектры излучения плазмы вращательного скользящего разряда с одним жидким электродом. Обнаружен эффективный механизм контроля уровня неизотермичности плазмы в динамических плазменно-жидкостных системах. Показан основной механизм выноса материала металлического анода в плазменно-жидкостной системе с вращательным скользящим разрядом.Розроблено плазмово-рідинну систему, в основі якої лежить обертальний ковзний розряд з одним рідким електродом. Досліджено спектри випромінювання плазми обертального ковзного розряду з одним рідким електродом. Виявлено ефективний механізм контролю рівня неізотермічності плазми в динамічних плазмово-рідинних системах. Показано основний механізм виносу матеріалу металевого аноду в плазмово-рідинній системі з обертальним ковзним розрядом

Plasma system with rotational gliding arc between solid electrodes

Rotational gliding arc with solid electrodes has been studied at different flow of working gas (air). Plasma torch studies by emission spectroscopy method. Measurements have been made at various levels from the electrode surface along the entire flare height. Electronic temperature levels of plasma component population have been determined. Current-voltage characteristics under different operating conditions were investigated.Досліджувалась обертова ковзна дуга з твердими електродами за різних потоків робочого газу (повітря). Проводилися дослідження плазмового факелa методом емісійної спектроскопії. Виміри проводились на різних рівнях від поверхні електроду вздовж усієї висоти факелa. Визначені температури заселення збуджених електронних рівнів компонент плазми. Досліджені вольт-амперні характеристики при різних режимах роботи.Исследовалась вращательная скользящая дуга с твердыми электродами при различных потоках рабочего газа (воздуха). Проводились исследования плазменного факела методом эмиссионной спектроскопии. Измерения проводились на разных уровнях от поверхности электрода вдоль всей высоты факела. Определены температуры заселения возбужденных электронных уровней компонент плазмы. Исследованы вольт- амперные характеристики при различных режимах работы

Effect of metal citrates on indicators of the embryotoxicity of cadmium salts in rats with combined introduction

The aim of the study was to determine the effect of metal citrates (cerium, zinc, iron) when combined with cadmium salts (chloride/citrate) on the embryotoxicity of cadmium in rats. The aim of the study was to determine the effect of metal citrates (cerium, zinc, iron) when combined with cadmium salts (chloride/citrate) on the embryotoxicity of cadmium in rats. Embryotoxic effects of test substances in groups were calculated and compared according to the following indicators: number of embryos, total, preimplantation, postimplantation embryonic mortality. Comparison of the embryotropic properties of cadmium chloride and cadmium citrate in the groups of isolated administration revealed a higher level of embryotoxicity of cadmium chloride. In the groups of combined administration, the greatest reduction in embryotoxicity was determined in the groups of the combination of cadmium with iron citrate for all studied indicators. embryogenesis, cadmium, cerium citrate, iron citrate, zinc citrate, embryonic mortality Метою дослідження було визначення впливу цитратів металів (церію, цинку, заліза) при комбінованому введенні з солями кадмію (хлориду/цитрату) на показники ембріотоксичності кадмію у щурів. Окрім контрольної групи, були 2 групи ізольованого введення кадмію і 6 груп комбінованого введення солей кадмію з цитратами металів (церій, цинк, залізо). Ембріотоксичну дію досліджуваних речовин в групах розраховували і порівнювали за наступними показниками: кількість ембріонів, загальна, доімплантаційна, післяімплантаційна ембріональна смертність. Порівняння ембріотропних властивостей хлориду кадмію та цитрату кадмію в групах ізольованого введення виявило більш високий рівень ембріотоксичності хлориду кадмію. У групах комбінованого введення найбільше зниження показників ембріотоксичності визначалося в групах комбінації кадмію з цитратом заліза по всіх досліджуваних показниках

Numerical method for three-dimensional macroscale simulations of two-phase flows with moving contact lines

Un modèle d'angle de contact dynamique est développé avec une méthode level-set pour simuler des écoulements macroscopiques tridimensionnels avec lignes de contact mobiles. Le code est validé à partir de simulations numériques directes et résultats expérimentaux d'étalement de gouttelette en régimes visqueux et inertiel. Le code permet de simuler des écoulements tridimensionnels avec ligne de contact mobile en tenant compte de l'hystérésis de l'angle de contact