Hydrodynamic Factors Research Articles

Interactions, Diffusion, and Membrane Fluctuations in Concentrated Unilamellar Lipid Vesicle Solutions

Lipid vesicles are widely used as models for cell membranes, hosts for membrane protein studies, and containers for hydrophilic molecules. The vesicle solutions in these applications are usually prepared at a specific lipid concentration; however, because vesicles are solvent-filled structures, the corresponding volume fraction of vesicles is at least a factor of three times higher than the corresponding lipid volume fraction and critically depends on the vesicle radii. Here we show that these higher than may be expected vesicle volume fractions result in measurable interactions between the vesicles as well as affect the vesicle diffusion. We show that vesicle solutions prepared with lipid mass fractions, mL, as low as ≈ 0.004, which correspond to a lipid concentration of ≈ 4 mg/mL or 5 mmol/L (mM), not only have a measurable apparent structure factor (S′(q)) in small angle neutron scattering (SANS) experiments, but that this repulsive structure factor also affects the measured diffusion coefficient at small scattering vectors (q) such as those probed with dynamic light scattering (DLS). The measured diffusion coefficients are further affected by indirect solvent mediated interactions described by a hydrodynamic factor (H(q)). Accounting for the concentration-dependence of the vesicle diffusion shows that the lipid concentration dependence measured in neutron spin echo (NSE) spectroscopy is due to differences in the effective vesicle diffusion coefficients and not the membrane fluctuation dynamics. The results have practical implications for static and dynamic scattering experiments as well as provide interesting insights into the interactions between soft lipid vesicles.

Hydrogeological, hydrodynamic and anthropogenic factors affecting the spread of pharmaceuticals and pesticides in water resources of the Granada plain (Spain)

The anthropogenic organic contaminants contemplated in the environmental legislation, as well as those of emerging concern, threaten the quality of water resources to a degree that remains largely unknown. Contaminant exposure in the aquatic environment is a crucial element if a full understanding of the risk is pursued. There are still many uncertainties about the occurrence of organic pollutants and behavior in the hydro(geo)logical media in large scale areas. The case study of the unconfined aquifer of the Granada Plain (approximately 200 km2) is presented here. Two surface and groundwater monitoring campaigns were conducted (March 2017 and June 2018). In total, 41 out of 171 target organic pollutants were detected, at least once: 17 pharmaceuticals or drugs of abuse, 21 pesticides or their metabolites and three polyaromatic hydrocarbons. In addition, physico-chemical parameters were measured during the monitoring campaigns and hydrochemical parameters and stable isotopes (δ2H, δ18O, δ13C) were analyzed. Statistical tests confirmed the significance of seasonal changes for some of these parameters (e.g., EC, Cl-, F-, δ18O, δ13C), revealing the influence from snowmelt water input on streams and the intensification of irrigation. In March 2017, the group of pesticides (largely represented by triazines) predominated, whereas the frequency of detection of pharmaceuticals increased substantially in June 2018. Results suggest four main factors affecting the spatial and seasonal variation of organic pollutants in the aquifer: the anthropogenic factor determining the period of contaminant release throughout the year (pesticide application period and growth of tourism) along with irrigation practices that include reclaimed wastewater; unsaturated zone thickness; hydraulic gradient and river-groundwater hydraulic connection. The latter can be especially important in the case of those contaminants whose main path of entry into the aquatic environment occurs through wastewater discharge into streams (i.e., pharmaceuticals).

Paleo-sea levels, Late-Holocene evolution, and a new interpretation of the boulders at the Rocas Atoll, southwestern Equatorial Atlantic

Rocas Atoll is a remote place and the only atoll in the southwestern Atlantic Ocean. This study presents new paleo-sea level reconstructions and a new interpretation on former ones. The new data indicate that sea level was higher at the Late-Holocene than it is at present and that the hydrodynamic factors overlap with sea-level changes, precluding more precise paleo-sea level reconstructions. According to previous works, the Rocas Atoll presents one of the most conspicuous paleo-sea level indicators, represented by reef remains. But, in this paper, these supposedly reef remains are reinterpreted as algal-reef boulders detached from the atoll reef-front by high-wave energy events and deposited over the reef rim, where they remain detached or are cemented and, sometimes, mushroom shaped. It is considered that the bigger boulders may have been deposited in their current position by the cumulative effects of past energetic wave events. Furthermore, the use of beachrocks as paleo-sea level indicators in former studies is discussed, leading to the conclusion that they actually indicate beach progradation and lateral accretion resulting from a positive sand budget. Finally, a schematic morphological evolution of the atoll during the Late-Holocene is proposed. At the atoll, leveling with RTK and imagery with laser scanner were collected, and eleven radiocarbon ages were measured by accelerator mass spectrometry (AMS).

FRACTAL-BASED MODEL FOR EVALUATING THE FILTRATION EFFICIENCY OF THE NON-WOVEN FIBROUS COMPOSITES

The classic single-fiber efficiency model based on ordered packing of fiber composites has been widely used to predict filtration efficiency of fibrous filters for 40 years. However, the simplified single-fiber model often overestimates the filtration efficiency as most fibrous composite filters are composed of randomly distributed fibers. The numerical methods have been successfully employed to re-construct the realistic fiber composites, but simulation of the multi-mechanism filtration process in the complex fibrous architecture is computationally expensive and case-based and derivation of a compact versatile model for broad applications remain challenging. In this work, a fractal-based homogenization model is developed to predict the filtration efficiency of the fibrous composites, by considering the spatially randomly distributed fibers and the quasi-random distribution of pore size. A comparison with available experimental results collected from references shows that the proposed model is of high accuracy in predicting the filtration of submicron aerosol particles. The calculated results show that the Kuwabara hydrodynamic factor is sensitive to the pore fractal dimension. The filtration efficiency for different particle diameters can be divided into three stages, which increase as the proportion of fibers warped by the fluid decreases. In addition, the total efficiency decreases with the increasing pore fractal dimension in a nonlinear trend. For the given fractal dimension, the filtration efficiency increases with the increase of pore size ratio, indicating that the more uniform the pore size distribution, the higher the efficiency.

Coastal erosion trend analysis using a combination of remote sensing and hydrodynamic models: Case study of Ca Mau Cape, Mekong Delta

BackgroundCoastal erosion and the loss of protective forest areas have recently become serious problems in the Ca Mau Cape (CMC) area of the Mekong Delta. Specifically, in 2016–2020, the rate of erosion in some subsections of the east coast reached 25–37 m/year and the forest area decreased significantly. ObjectivesTo analyse erosion and accretion trends in the period 2016–2020 and to determine the mechanism underlying erosion in the CMC using a hydrodynamic model focused on tides, currents, waves, and sediment transport. MethodsSatellite images (Google Earth), remote sensing images (Landsat 8 OLI/TIRS C1 Level-1), and a combination of hydrodynamic modules were used to evaluate the combined effects of tides, currents, waves, and sediment transport on erosion. ResultsRemote sensing image analyses revealed that the east coast has a very high rate of erosion, with the highest erosion rates of 35 m/year in both 2016–2018 and 2019–2020, while the west coast showed an accretion trend in 2016–2018, followed by strong erosion in 2019–2020, with a rate of 10 m/year. Hydrodynamic models showed that hydrodynamic factors, such as tides, currents, waves, and a low suspended sediment concentration (SSC), directly contribute to the erosion trend in the area. The differences in water level between the high tide and low tide on the east coast, reaching 2 m (dry season) and 0.8 m (wet season), were consistently two times higher than those on the west coast, i.e. 0.9 m (dry season) and 0.4 m (wet season). The flow rates on the east coast (i.e. 0.4–0.6 m/s, on average) were significantly higher those on the west coast (0.2 m/s, on average). Wave heights on the east coast, reaching 1.5–2 m in the dry season and 0.6–1 m in the wet season, were consistently higher than those on the west coast, reaching 1–1.2 m (dry season) and 0.4–0.6 m (wet season). In addition, the SSC was lowest under strong erosion, with average concentrations of 0.04–0.06 kg/m3 in the wet season and 0.02–0.04 kg/m3 in the dry season. The SSC was highest in the sections showing accretion trends, with concentrations of >0.3 kg/m3 in the wet season and 0.08–0.1 kg/m3 in the dry season. ConclusionEvaluating shoreline changes using remote sensing technology and validating these results using hydrodynamic models provides a better understanding of the mechanism underlying coastal erosion and its development and provides a basis for the development of a coastal protection strategy.

The Effect of Blood Pressure Variability on Coronary Atherosclerosis Plaques.

Hypertension is one of the most important risk factors for coronary heart disease (CHD). The regulation of blood pressure plays a significant role in the development and prognosis of CHD. Blood pressure variability (BPV) refers to the degree of fluctuation of blood pressure over a period of time and is an important indicator of blood pressure stability. Blood pressure fluctuations are complex physiological phenomena, being affected by physiological and pharmacological effects and regulated by behavioral, environmental, hydrodynamic, and neural factors. According to the different time periods for measuring BPV, it can be divided into very short-term, short-term, mid-term, and long-term. Multiple cardiovascular disease animal models and clinical experiments have consistently indicated that abnormal BPV is closely related to coronary events and is a risk factor for CHD independently of average blood pressure. Thrombosis secondary to plaque rupture (PR) or plaque erosion can cause varying blood flow impairment, which is the main pathological basis of CHD. Plaque morphology and composition can influence the clinical outcome, treatment, and prognosis of patients with CHD. Research has shown that PR is more easily induced by hypertension. After adjusting for the traditional factors associated with plaque development, in recent years, some new discoveries have been made on the influence of abnormal BPV on the morphology and composition of coronary plaques and related mechanisms, including inflammation and hemodynamics. This article reviews the impact of BPV on coronary plaques and their related mechanisms, with a view to prevent the occurrence and development of CHD by controlling BPV and to provide new prevention and treatment strategies for the clinical treatment of abnormal blood pressure.

Influence of network defects on the conformational structure of nanogel particles: From "closed compact" to "open fractal" nanogel particles.

We propose an approach to generate a wide range of randomly branched polymeric structures to gain general insights into how polymer topology encodes a configurational structure in solution. Nanogel particles can take forms ranging from relatively symmetric sponge-like compact structures to relatively anisotropic open fractal structures observed in some nanogel clusters and in some self-associating polymers in solutions, such as aggrecan solutions under physiologically relevant conditions. We hypothesize that this broad "spectrum" of branched polymer structures derives from the degree of regularity of bonding in the network defining these structures. Accordingly, we systematically introduce bonding defects in an initially perfect network having a lattice structure in three and two topological dimensions corresponding to "sponge" and "sheet" structures, respectively. The introduction of bonding defects causes these "closed" and relatively compact nanogel particles to transform near a well-defined bond percolation threshold into "open" fractal objects with the inherent anisotropy of randomly branched polymers. Moreover, with increasing network decimation, the network structure of these polymers acquires other configurational properties similar to those of randomly branched polymers. In particular, the mass scaling of the radius of gyration and its eigenvalues, as well as hydrodynamic radius, intrinsic viscosity, and form factor for scattering, all undergo abrupt changes that accompany these topological transitions. Our findings support the idea that randomly branched polymers can be considered to be equivalent to perforated sheets from a "universality class" standpoint. We utilize our model to gain insight into scattering measurements made on aggrecan solutions.

Mangrove forest: An important coastal ecosystem to intercept river microplastics

The research on transportation of river microplastics (MPs) mainly focuses on the estimations of the total contents of river MPs entering the ocean, while the related transportation processes and influence factors were still largely unknown. In our study, the role of mangrove forest, a special tropical ecosystem in the estuary, on the transportations of MPs from rivers to ocean was explored. Except for the ND river with the absence of mangrove forest, the MPs collected from the water sample of the river upstream were much higher than their corresponding downstream (p < 0.05), with the interception rate of riverine MPs by mangrove forests ranging from 12.86% to 56% in dry season and 10.57%–42% in rainy season. The MPs with the characteristics of high density, larger size and regular shape were more easily intercepted. Furthermore, the combined effects of ecological indicators, the properties of mangrove and the hydrodynamic factors jointly determined the interception rates of MPs. This study provides a new perspective and data support for quantifying mangrove forests intercepting MPs in rivers as a factor of MPs retention in global rivers.

Structure and hydrodynamic factors in lipid vesicle solutions

Lipid vesicles are widely used as models for cell membranes and extracellular vesicles, hosts for membrane protein studies, and containers for hydrophilic biotherapeutic molecules. Vesicle solutions are usually prepared at a specific lipid concentration; however, because vesicles are solvent-filled structures, the corresponding volume fraction of vesicles is at least a factor or 3 times higher than the corresponding lipid volume fraction and critically depends on the vesicle radii. Seemingly low lipid concentrations correspond to significantly higher vesicle volume fractions and closer face-to-face distances between their surfaces than may be expected.

Assessment of the Coastal Vulnerability Index (CVI) for disaster mitigation strategies in some coastal tourism areas in Gunungkidul, Yogyakarta-Indonesia

South coastal area of Gunungkidul, Yogyakarta-Indonesia has a high tourism development due to the unique physical conditions of coastal typology. However, during the last few years, extreme wave height associated with cyclones damaged many tourist facilities there. Coastal management for ecosystem sustainability requires disaster mitigation, which one considering the aspect of vulnerability. This study aims to assess the level of coastal vulnerability according to coastal typology of Baron-Pok Tunggal section and to determine the coastal management model based on the level of vulnerability. The Coastal Vulnerability Index (CVI) is used in vulnerability assessment. The variable formulation of CVI is divided into hydrodynamic factors (mean significant wave heights, mean tide range, and mean sea level rise) and morphodynamics factors, i.e. geomorphology, coastal slope, and average width of emerged beach. The morphodynamics data were obtained through observation, direct measurements in the field by systematic sampling, extraction from aerial photographs and digital surface model (DSM). The results of modeling and predictions by several agencies are derived to obtain the hydrodynamics data. The result of this study revealed that marine deposition coast typology have a high and moderate vulnerability (twelve and eleven coastal units, respectively). Meanwhile, a low vulnerability can be found in the cliff coast or wave erosion coast typology (24 units). The convex or concave beaches tend to be more vulnerable than beaches with the straight form. The beaches of Buluk, Drini, Kosakora, Sarangan and all beaches from Krakal to Indrayanti have a high vulnerability. Geomorphological variables, significant wave height, and sea level rise have the strongest influence on vulnerability. Coastal management in the marine deposition coast typology can be carried out either in a protective manner or by accommodative approach, such as by observing changes in natural conditions due to sea level rise.

Effects of multiple flexible vortex generators on the hydrothermal characteristics of a rectangular channel

Plenty of numerical or experimental studies have been devoted to the hydrothermal characteristics of heat sinks with multiple vortex generators (VGs). In this study, in order to boost the heat transfer rate and reduce the hydrodynamic dissipations, VGs are chosen to have flexible splitter on their lee sides. Also, VGs are selected at different axial and transverse inter-distances. The Reynolds number, based on the channel's hydraulic diameter, is set to 1000 to ensure laminar flow. The heat transfer performance, the hydrodynamic friction factor and the overall hydrothermal efficiency for different number of VGs and splitter's flexural rigidity are investigated. The results showed that flexible splitters provide better heat transfer capability and the higher hydrothermal performance compared to rigid ones. The results also indicated that, by selecting proper configuration, in the expense of 10% decrease in total hydrothermal efficiency with respect to clean channel, 190% increase in the rejected heat can be achieved.

Friction model of elastic-plastic line contact in mixed lubrication regime with non-Newtonian lubricant

The friction characteristics of the lubricated rough surfaces are of great significance for the lubrication design of mechanical structures. To study the behaviour of friction coefficient in the rolling-sliding coexisting line contact rough surfaces under mixed lubrication regime, the Kogut-Etsion elastic-plastic model and the Carreau rheological model are utilized to describe the dry rough contact and the non-Newtonian characteristics of the lubricant film, respectively. A mixed lubrication model for predicting friction coefficient is proposed based on the load-sharing concept at which the normal load is shared by the lubricant film and the asperity component. The effects of normal load, surface roughness and lubricant inlet viscosity on hydrodynamic scaling factor, film thickness parameter and the coefficient of friction were analyzed. The dimensionless predictive expression for the critical sliding velocity is derived by nonlinear regression. The research results provide theoretical guidance for the lubrication design and optimization of mechanical structures.

Sedimentary and reservoir characteristics of an Oligocene-Miocene mixed siliciclastic-carbonate succession in southeast Iraq

The Cenozoic mixed siliciclastic-carbonate succession in southeastern Iraq is an essential and unique reservoir in the region. However, the current understanding of its sedimentology and reservoir characteristics is insufficient. In this study, its sequence stratigraphy, depositional history, and reservoir characteristics are investigated by combining seismic and well log data, core observations, and porosity and permeability measurements from several oilfields in southeastern Iraq. Two types of shallow marine deposits in two third-order sequences are established. Ten facies associations are identified in the mixed siliciclastic-carbonate deposit: the carbonate-dominated type, including sabkha, lagoon, intertidal-subtidal mudflat sandflat, and shoal; the mixed type, including foreshore and shoreface, and; the siliciclastics-dominated type, including distributary channel, interdistributary bay, and crevasse. The lower third-order sequence formed in a siliciclastic delta-dominated shallow marine system, resulting in two patterns of reciprocal mixed deposition, one forming between different system tracts and the other forming between thin carbonate and sandstone layers in the highstand system tract; the factors controlling the deposition of this reciprocal mixed system include allocyclic processes such as sediment supply, sea-level change, and tectonic activities. In contrast, the upper third-order sequence was deposited in a carbonate tidal-dominated shallow marine system, mainly forming a coeval mixed deposition controlled by various hydrodynamic factors. The reservoir quality of the coeval mixed reservoir is facies dependent and diagenesis influenced. The shoreface and parts of the tidal mudflat and lagoon are the favorable reservoir facies; in this reservoir, the strong hydrodynamic depositional environment and the syn-depositional selective dissolution are the advantageous controlling factors. In the reciprocal mixed reservoir, the petrophysical properties of the sandstone layers are better than that of the carbonate layers, causing the carbonate layers to act as interlayers or baffles to some extent. Thus, horizontal well fracturing and vertical wells are recommended for exploiting the coeval and reciprocal mixed reservoirs, respectively. This study helps to better understand mixed siliciclastic-carbonate reservoirs and provides support for oil development in the Middle East region.

Modeling of the influence of the bath blowing mode on mass exchange processes and slag formation in the oxygen converter

Рurpose. Establish rational modes of bath blowing and slag formation when using traditional and experimental materials that ensure effective refining of steel from harmful impurities. To investigate the influence of the change in the hydrodynamic state of the converter bath on the stability of the lining of problem areas of the converter and the loss of metal with removal, emissions, with metal balls merging with the slag. Method. The work uses methods of cold and high-temperature modeling of the steel smelting process. When conducting experiments on cold modeling, the mode of penetration of gas jets into the liquid on the sample and the model was observed with the provision of Lrz/Nv (model) = Lrz/Nv (converter). Nv is the depth of the bath on the model and the wor king converter. Lrz - the length of the reaction zone in high-temperature simulations was determined as the length of the primary reaction zone, and in the cold one - as the length of the jet section formed when the gas jet penetrates the liquid. These conditions, together with ensuring the similarity of the geometry of the model and the sample, were consi dered necessary and sufficient for obtaining data for qualitative and quantitative assessment of both the hydrodynamic state of the converter bath and the effect of changing the method and parameters of blowing the bath on the physicochemical features of steel refining according to the time of the process. An additional condition is compliance with the condition of equality of the ratio of the plane of the bath to the plane of the internal section of the nozzle of the blowing nozzle: (Sbaths/Snozzles) model=(Sbaths/Snozzles) sample on the model and sample. Scientific novelty. Theoretically substantiated and experimentally confirmed the expediency of using to determine the effect on physico-chemical processes and conversion in the converter bath of the blowing mode, for the characteristic of which the parameter - hydrodynamic factor equal to the ratio LrzI/Nv was chosen. In turn, the length of the reaction zone that remains when the gas jet enters the bath depends on the intensity of blowing: Lrz ~ K q0.4. For the first time, the parameter that determines the state of mixing of the bath during its oxygen blowing - LrzI/Nv - was used to determine the intensity of sulfur conversion into slag during the oxygen blowing of the iron-carbon melt of the converter bath for the range of changes in the carbon content in it 3.0...0.25. where LrzI is the length of the primary reaction zone, which is formed when the oxygen jet penetrates the metal melt. The primary reaction zone is the source of the formation of CO bubbles according to the reaction FeO + C = Fe + CO, which are responsible for the intensity of mixing of the bath through the formation of circulating flows of metal in the bath, which in turn are responsible for the transport of impurity elements to the metal-slag boundary. It is shown that in the given range of changes in the content of carbon in the metal melt, the dependence of the removal rate of sulfur from the metal into the slag on the hydrodynamic parameter LrzI/Nv is extreme. At this time, when the maximum mixing effect of the bath is achieved, in the presence of the necessary basicity of the slag phase, the speed of the desulfurization reaction for these conditions is maximum. In the future, in the case of the implementation of the traditional conversion scheme, which is characterized by a sharp increase in the content of iron oxides in the slag (15...17%), the speed of the desulfurization reaction decreased even with a sufficient speed of metal flows. Practical significance. Reducing the intensity of metal bath blowing in the conditions of steel smelting in a laboratory oxygen converter with upper oxygen blowing from 4.0 m3/t•min to 3.2 m3/t•min, while increasing the blowing time by 17.8%, increased the desulphurization rate . Bringing the desulfurization reaction to its fuller completion was achieved due to the rational organization of mixing the melt in the converter bath: the appropriate and effective rate of metal delivery to the reaction surface from the point of view of the completion of steel desulfurization ensured a higher speed of the desulfurization reaction at the border compared to more intensive blowing of the bath with oxygen metal-slag distribution. At the same time, the value of the indicator Ls =(S)/[S] increased from 6.4 to 10.5.

Effectiveness of hazard control through HACCP critical control points in the wet noodle production process on product quality

The cavitation phenomena should be considered during the design of hydrokinetic turbines due to cavitation could cause surface erosion, mechanical vibrations, undesirable noise and efficiency reduction in the energy transformation. Therefore, the aim of this work is to conduct a numerical comparison of the cavitation resistance of 3 hydrofoils (NACA0015, Eppler420 and S822) with the purpose of selecting the best foil for the blade cross-section design. For each hydrofoil, the traditional and the high-lift configurations were evaluated. The hydrodynamic factors, including the lift and the drag (CL and CD, respectively) coefficients were determined by using JavaFoil software for several angles of attack (α). Additionally, for the computational fluid dynamics (CFD) study in ANSYs Fluent software, the SST k-ω and the Schnerr and Sauer turbulence and cavitation models were respectively utilized to validate the values of CL and CD, and to calculate the pressure coefficient (CP). The values of CP were compared with the cavitation number (σ) for identifying cavitation on the blade and comparing the cavitation resistance of the hydrofoils studied. The methods used and the numerical results obtained were subsequently analyzed and validated using relevant experimental values available in the literature for the NACA0015 hydrofoil. CFD simulations revealed that the NACA0015 traditional hydrofoil and the high-lift configuration of the Eppler420 hydrofoil have the best resistance to cavitation inception in comparison with the traditional hydrofoils and the high-lift configurations studied, respectively.

Comparative study of the cavitation resistance of the traditional and high-lift hydrofoils for hydrokinetic application

The cavitation phenomena should be considered during the design of hydrokinetic turbines due to cavitation could cause surface erosion, mechanical vibrations, undesirable noise and efficiency reduction in the energy transformation. Therefore, the aim of this work is to conduct a numerical comparison of the cavitation resistance of 3 hydrofoils (NACA0015, Eppler420 and S822) with the purpose of selecting the best foil for the blade cross-section design. For each hydrofoil, the traditional and the high-lift configurations were evaluated. The hydrodynamic factors, including the lift and the drag (CL and CD, respectively) coefficients were determined by using JavaFoil software for several angles of attack (α). Additionally, for the computational fluid dynamics (CFD) study in ANSYs Fluent software, the SST and the Schnerr and Sauer turbulence and cavitation models were respectively utilized to validate the values of CL and CD, and to calculate the pressure coefficient (CP). The values of CP were compared with the cavitation number (σ) for identifying cavitation on the blade and comparing the cavitation resistance of the hydrofoils studied. The methods used and the numerical results obtained were subsequently analyzed and validated using relevant experimental values available in the literature for the NACA0015 hydrofoil. CFD simulations revealed that the NACA0015 traditional hydrofoil and the high-lift configuration of the Eppler420 hydrofoil have the best resistance to cavitation inception in comparison with the traditional hydrofoils and the high-lift configurations studied, respectively.

Development and numerical implementation of an algorithm for simulation the pollutant transport in water environment taking into account their destruction and deposition

The paper covers the development of an algorithm for modeling the pollutant distribution dynamics in shallow water and its implementation on a high-performance computer system in a limited time. A mathematical model of the pollutant transport, including oil and petroleum products, in the water environment has been developed taking into account a number of determining hydrodynamic and hydrophysical factors, including destruction and deposition, affecting the nature of their flow. Methods of its numerical implementation have been developed for prediction the pollution spread in shallow waters in limited time on a high-performance computer system. The main advantage of it in predictive modeling of environment processes and phenomena is taking into account the multidisciplinary nature of real processes, the complex geometry of simulated domain, ensuring high accuracy of calculations, performing a large number of calculations in a short time. Simulation of the pollutant transport of various etiologies was performed taking into account a number of determining factors, including their structure and deposition on the bottom surface, on the basis of the developed software and algorithmic tools. It used a scenario approach that meets the basic principles of effective predictive modeling in water systems. The simulation results are the foundation for planning and conducting measures to prevent and eliminate the consequences of technogenic hazards.

Alternative Method for Stability Assessment of Indonesian Traditional Wooden Boats

Due to the small down-flooding angle, the available intact stability criteria were difficult to apply to an Indonesian traditional wooden. This paper discusses the application of the dead ship criteria of Second Generation Intact Stability Criteria as an alternative method to assess the stability of the Indonesian traditional wooden boats. The hydrodynamics factors correspond to the formula to calculate the heel angle due to wave were determined by model experiments. The calculations were conducted for four different down-flooding angles consisting of 20 degrees, 25 degrees, 30 degrees and 35 degrees with scattered wave data of Lombok Strait. The results showed that the critical metacentric height decreases if the down-flooding angle increases. The minimum area under the righting arm curve up to the down-flooding angle tends to be independent of the down-flooding angle. The capsizing index corresponds to the critical metacentric height decreased when the down-flooding angle increased. These results showed that the method to assess ship stability in the Second Generation Intact Stability Criteria could be used to evaluate the stability of the Indonesian traditional wooden boats.

On formation of padder syndrome

Edematous syndrome is most common among patients of older age groups and indicates pathology on the part of such organ systems as cardiovascular, genitourinary, musculoskeletal, lymphatic, endocrine. The causes of edema are diverse, and the tactics of further management due to incorrect justification can lead to serious consequences.The purpose of this study. To study the prevalence and differential diagnostic features of edematous syndrome based on the analysis of current scientific publications containing information on this topic.Results. The development of edematous syndrome is caused by a number of factors, the main of which are: hydrodynamic factor, osmotic factor, oncotic pressure, membranogenic factor. Despite the fact that edematous syndrome is associated with many diseases, it has specific differential diagnostic signs for each pathology.Conclusions. Edema is a visible objective symptom and is a root cause factor of various diseases, such as glomerulonephritis, thrombophlebitis, filariasis, cirrhosis, chronic heart failure, shock, allergic, inflammatory conditions and many others. However, with the help of specific clinical features of the symptoms of this syndrome, it is possible to make a differential diagnosis and determine the underlying disease that led to the formation of edematous syndrome.

Identification and research of factors affecting the optimal distribution of well flow rates in space

The paper discusses and research the factors affecting the filtration rate to reduce stagnant zones in the domain and spreading outside the block under consideration. The main hydrodynamic factors in production by In-Situ Leaching are the distribution of permeability in the reservoir and well flow rates. The study of the factors was carried out on the basis of mathematical models using Darcy Law and Law of Conservation of Mass. Calculation was accomplished on a two-dimensional area with an isotropic and non-uniform permeability distribution to determine the effect of permeability on the leached area. The permeability coefficient was distributed respectively over three zones, in the southern part the permeability was low, in the central transition from low to high, respectively, in the northern part there was a highly permeable zone. Three wells were located in the domain, with the production well in the center of the domain. Injection wells are located symmetrically with respect to a horizontal line passing through the center of the area under consideration. The calculation was carried out for three modes of well flow rates with the ratio of the flow rates of the injection wells 0.5 / 0.5, 0.2 / 0.8, 0.8 / 0.2 relative to the flow rate of the production well. On the basis of comparative analyzes of the obtained results, it is concluded that: at the same flow rates, regardless of the permeability of the zones, the results obtained show that the leaching area in the low-permeability zone is larger in comparison with the high-permeability zone; with an increase in permeability, the shape of the leaching zone tends from round to drop-shaped; with an increase in the flow rate of wells in the radius of the leaching zone, it increases if the flow rate of solutions is much higher than the filtration rate.