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It is shown that black holes in a quark gluon plasma (QGP) obeying minimum viscosity bounds exhibit a Schwarzschild radius in close match with the range of interaction of the strong force. For such black holes, an evaporation time of about 1016 s is estimated, indicating that they would survive by far the quark-gluon plasma era, namely between 10−10 and 10−6 s after the big bang. On the assumption that the big-bang generated unequal amounts of quark and antiquarks, this suggests that such unbalance might have survived to this day in the form of excess antiquark nuggets hidden to all but gravitational interactions. A connection with the saturon picture, whereby minimum viscosity regimes would associate with the onset coherent quantum field structures with maximum storage properties, is also established. [ABSTRACT FROM AUTHOR]

Public transport focuses on meeting the transport needs of people both within the city and in the suburban area. Passenger transport is a key element of sustainable development and improving the quality of life in agglomerations because it provides mobility for residents and tourists. In recent years, residents have become increasingly willing to use public transport. However, this trend was disrupted as a result of global changes taking place in the years 2019 - 2022. The aim of this publication was to analyse and assess the impact of crisis situations on the implementation of transport processes using the example of public transport in Warsaw. It has been shown that events such as the COVID-19 pandemic or the war in Ukraine also had a significant impact on the functioning of transport processes in Warsaw public transport. The study made it possible to identify recommendations aimed at securing the operation of public transport in the event of similar threats in the future.

Public transport focuses on meeting the transport needs of people both within the city and in the suburban area. Passenger transport is a key element of sustainable development and improving the quality of life in agglomerations because it provides mobility for residents and tourists. In recent years, residents have become increasingly willing to use public transport. However, this trend was disrupted as a result of global changes taking place in the years 2019 - 2022. The aim of this publication was to analyse and assess the impact of crisis situations on the implementation of transport processes using the example of public transport in Warsaw. It has been shown that events such as the COVID-19 pandemic or the war in Ukraine also had a significant impact on the functioning of transport processes in Warsaw public transport. The study made it possible to identify recommendations aimed at securing the operation of public transport in the event of similar threats in the future. [ABSTRACT FROM AUTHOR]

A novel averaging of the conservation equations for axial flow in packed beds is presented to express the momentum, continuity, and energy equations in terms of the cross‐sectional averages of concentration, temperature, and superficial velocity. The model integrates the radial fluctuations of the intrinsic variables into the partial differential equations of the model and presents a method for the design and analysis of catalytic reactors at a broad range of Reynolds numbers without the necessity of adjusting the operating conditions to minimize the impact of the radial profiles of velocity, concentration, and temperature. Since the control of the industrial reactors is dependent on the average values of the concentration and temperature, the model can be directly employed for design, optimization, and control processes with the added advantage of time and cost savings for both the numerical resolution and laboratory testing expenses. The model is limited to reaction systems with Péclet numbers of less than 700 with an average void fraction of εb for which the ratio of the bed length‐to‐particle diameter to particle Péclet number exceeds 0.3εb1−εb. The model was applied to the simulation of steam methane reforming (SMR). The results indicate that the average equations predict the responses of the SMR properly and thus the model could be reliably utilized for process design, operation, and control. [ABSTRACT FROM AUTHOR]

We consider the macroscopic limit for the space-time density fluctuations in the open symmetric simple exclusion in the quasi-static scaling limit. We prove that the distribution of these fluctuations converge to a gaussian space-time field that is delta correlated in time but with long-range correlations in space. [ABSTRACT FROM AUTHOR]

Copyright of Polish Journal of Management Studies is the property of Czestochowa University of Technology, Faculty of Management and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Mismanaged plastic waste threatens the sustainable development goals of the United Nations in social, economic, and ecological dimensions. In the pollution process, fluvial systems are critical transport paths for mismanaged plastic waste, connecting land areas with oceans and acting as plastic reservoirs and accumulation zones. The complex fluid–plastic particle interaction leads to a strong distribution of transported particles over the entire river width and flow depth. Therefore, a holistic plastic removal approach must consider lateral and vertical river dimensions. This study investigates the conceptual design of a comprehensive river-cleaning system that enables the removal of both floating and suspended litter particles from watercourses withstanding flow variations. The innovative technical cleaning infrastructure is based on a self-cleaning system using rotating screen drum units. In 42 prototype-scale experiments using ten representative plastic particle types (both 3D items and fragments) of five different polymer types, we prove the self-cleaning concept of the infrastructure and define its parameters for the best cleaning performance. Its cleaning efficiency is strongly dependent on the polymer type and shape. The overall cleaning efficiency for 3D items amounts to 82%, whereas plastic fragments are removed less efficiently depending on hydraulic conditions. Adaptions to the prototype can enhance its efficiency. [ABSTRACT FROM AUTHOR]

Sulfate is a potential pollutant and important nutrient linked with the nitrogen, carbon, and phosphorus cycles. The importance of different anthropogenic sulfate sources in suburban streams (septic systems, fertilizer, road salt, and infrastructure) is uncertain, and the temporal dynamics of stream export sparsely documented. We study sources and export dynamics of sulfate in suburban and forested headwater catchments. Stream baseflow discharge and sulfate concentrations were strongly positively correlated in both watersheds with the highest values in spring. Suburban concentrations and fluxes (2.48–7.5 mg/L or 25.8–78.1 μM, 16.6 kg/ha/yr) were consistently higher than forested (0.56–2.78 mg/L or 5.8–28.9 μM, 5 kg/ha/yr). Following precipitation, sulfate concentrations in both forested and suburban streams increased to concentrations above pre‐storm values and remained high after peak discharge. These dynamics suggest that both catchments have a large pool of sulfate that can be mobilized under wet conditions. Ridge‐top forest soil samples contained 210 kg/ha stored, extractable sulfate. Current atmospheric sulfate deposition rates (5–7 kg/ha/yr) are approximately in balance with sulfate export in the forested stream. In the suburban watershed, we estimated septic fields contribute up to 11 kg/ha/yr (about half from surfactants) and lawn care up to 4.3 kg/ha/yr and are the most likely sources of elevated stream sulfate. Sulfate sulfur (4.9–5.8‰ forested; 6.1–7.0‰ suburban) and oxygen isotope values (0.7–2.0‰ forested; −0.1–4.1‰ suburban) are consistent with this interpretation, but do not provide strong corroboration due to large variation and overlap in estimated source values. Plain Language Summary: Sulfate can be a nutrient or pollutant that alters stream biogeochemistry depending on dissolved concentrations. For decades, atmospheric sulfur deposition was elevated due to regional anthropogenic emissions. Regulation in the 1990s resulted in decreasing deposition and increasing importance of other sulfur sources, for example, associated with land use. We studied suburban sulfate sources, including infrastructure and activities not widely recognized as sources of stream sulfate. We measured dissolved sulfate concentrations and sulfate tracer isotopes in neighboring forested and suburban watersheds. Sulfate inputs and exports are compared with budgets of possible sulfate contributions to the stream from septic systems, lawn care, road salt, building materials, and historic agriculture. The suburban stream exports about 3x more sulfate a year from the watershed than the forested stream. Extra suburban stream sulfate appears to be largely caused by human waste and cleaning products flowing to septic fields and lawn care. More sulfate is transported to the stream during the wetter spring and after rain. This elevated transport may be because the groundwater table moves upwards during wetter times and transports sulfate that was stored in soil to the stream. Identifying suburban sources of sulfate pollution is important to protecting stream health. Key Points: The suburban stream has elevated sulfate concentrations and fluxes, likely due to contributions from septic systems and lawn careSulfate mobilized in seasonal‐ and event‐scale wet conditions in both forested and suburban streamsSulfate in the suburban stream is associated with soil storage mobilized in wet conditions, not runoff from impervious surfaces [ABSTRACT FROM AUTHOR]

Various examples show that stratified columns can improve the transport performance of particle packings. However, to date, there is no universal strategy to design these packings to yield optimal performance. This study proposes a model‐based approach for designing particle packings in which mass transfer occurs between a liquid phase and a stationary phase using optimal control theory. The primary objective is to provide a general design strategy that is applicable across different unit operations in chemical, pharmaceutical, and food applications. Optimal control is utilized to determine the optimal particle diameter as a function of the axial position within the column. We demonstrate the approach using two case studies and three different optimization criteria. Numerical results indicate that the proposed method is highly effective, for example, the solvent demand is reduced by up to 32.47%. Moreover, the optimally graded packing yields a significantly sharper breakthrough curve of an adsorption column. [ABSTRACT FROM AUTHOR]

According to intermediate band (IB) theory, it is possible to increase the efficiency of a solar cell by boosting its ability to absorb low-energy photons. In this study, we used a hyperdoped semiconductor approach for this theory to create a proof of concept of different silicon-based IB solar cells. Preliminary results show an increase in the external quantum efficiency (EQE) in the silicon sub-bandgap region. This result points to sub-bandgap absorption in silicon having not only a direct application in solar cells but also in other areas such as infrared photodetectors. To establish the transport mechanisms in the hyperdoped semiconductors within a solar cell, we measured the J â€" V characteristic at different temperatures. We carried out the measurements in both dark and illuminated conditions. To explain the behavior of the measurements, we proposed a new model with three elements for the IB solar cell. This model is similar to the classic two-diodes solar cell model but it is necessary to include a new limiting current element in series with one of the diodes. The proposed model is also compatible with an impurity band formation within silicon bandgap. At high temperatures, the distance between the IB and the n-type amorphous silicon conduction band is close enough and both bands are contacted. As the temperature decreases, the distance between the bands increases and therefore this process becomes more limiting. [ABSTRACT FROM AUTHOR]

Due to scale effects, directly enlarging the size of the micromixer is an easy way to reduce the efficiency of mass and heat transfer in the continuous flow chemical process. It is urgently needed to solve the problem of mass and heat transfer efficiency of the scale‐up mixer. A scale‐up microfluidic mixer with a porous structure was designed to improve the mass and heat transfer efficiency using computational fluid dynamics (CFD) simulations. The effects of rotation angle, porosity, and baffle spacing were studied to optimize the mixer structure. Compared with the 1 mm mixer without structure, the scale‐up mixer has a higher mixing efficiency and an 80% reduction in energy consumption at Re ≥ 700. A Nusselt number was used to evaluate the heat transfer efficiency of the mixer during fluid heating. The results show that the porous baffle promotes the generation of secondary flow and enhances the heat transfer effect, making its Nu increase by three times compared with the unstructured mixer. The scale‐up microfluidic mixer with a porous structure can effectively improve the mass and heat transfer performance. This study can provide a reference for the design or development of a novel scale‐up mixer. [ABSTRACT FROM AUTHOR]

Equilibrium thermodynamics answers the question, "by how much?" Nonequilibrium thermodynamics answers the question "how fast?" The physicochemical mechanics approach presented in this article answers both of these questions. It also gives equilibrium laws and expressions for all major transport coefficients and their relations, which was previously impossible. For example, Onsager's reciprocal relations only tell us that symmetric transport coefficients are equal, and even for these, the value is often not known. Our new approach, applicable to non-isolated systems, leads to a new formulation of the second law of thermodynamics and agrees with entropy increase in spontaneous processes for isolated systems. Instead of entropy, it is based on a modified Lagrangian formulation which always increases during system evolution, even in the presence of external fields. This article will present numerous examples of physicochemical mechanics can be applied to various transport processes and their equilibriums, including thermodiffusion and different surface processes. It has been proven that the efficiency of a transport process with an actual steady-state flux (as opposed to a reversible process near equilibrium) is 50%. Finally, an analogy between physicochemical mechanics and some social processes is mentioned. [ABSTRACT FROM AUTHOR]

Abstract Techniques for tissue culture have seen significant advances during the last decades and novel 3D cell culture systems have become available. To control their high complexity, experimental techniques and their Digital Twins (modelling and computational tools) are combined to link different variables to process conditions and critical process parameters. This allows a rapid evaluation of the expected product quality. However, the use of mathematical simulation and Digital Twins is critically dependent on the precise description of the problem and correct input parameters. Errors here can lead to dramatically wrong conclusions. The intention of this review is to provide an overview of the state‐of‐the‐art and remaining challenges with respect to generating input values for computational analysis of mass and momentum transport processes within tissue cultures. It gives an overview on relevant aspects of transport processes in tissue cultures as well as modelling and computational tools to tackle these problems. Further focus is on techniques used for the determination of cell‐specific parameters and characterization of culture systems, including sensors for on‐line determination of relevant parameters. In conclusion, tissue culture techniques are well‐established, and modelling tools are technically mature. New sensor technologies are on the way, especially for organ chips. The greatest remaining challenge seems to be the proper addressing and handling of input parameters required for mathematical models. Following Good Modelling Practice approaches when setting up and validating computational models is, therefore, essential to get to better estimations of the interesting complex processes inside organotypic tissue cultures in the future.

Copyright of Polish Journal of Management Studies is the property of Czestochowa University of Technology, Faculty of Management and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The flow of the gravity current plays an important role in the transportation and mixing of dissolved or suspended nutrients and chemical substances. In this study, from the experiments and numerical simulations of locked-exchange flow, the flow structure at the head of the gravity current was investigated. In a rectangular channel, a finite volume of fluid was instantaneously released into another fluid of slightly different density. A comparison of theoretical methods, experiments and numerical simulations showed that the water depth and volume of the released fluid affected the velocity of the gravity current. In the initial stage, the head moved forward at a constant velocity and then decelerated. In the final stage, which was governed by viscosity, the front velocity decreased proportionally to the time to the power of 1/2 when the head was not disturbed from behind. Gravity current created a mass concentration at the head in the initial stage. As the mass concentration at the head decreased, the gravity current was slowed down by the viscous stage due to the effect of the bottom friction according to the theoretical analysis. In the viscous stage, the mass concentration at the head no longer existed. The transition stage from the initial stage to the viscous stage was shown to vary with the Reynolds number by the numerical simulation. Clarification of the behavior of the leading edge of gravity flow will help predict the formation of mass transport in oceans and lakes, contributing to the conservation of the aquatic environment. [ABSTRACT FROM AUTHOR]

Techniques for tissue culture have seen significant advances during the last decades and novel 3D cell culture systems have become available. To control their high complexity, experimental techniques and their Digital Twins (modelling and computational tools) are combined to link different variables to process conditions and critical process parameters. This allows a rapid evaluation of the expected product quality. However, the use of mathematical simulation and Digital Twins is critically dependent on the precise description of the problem and correct input parameters. Errors here can lead to dramatically wrong conclusions. The intention of this review is to provide an overview of the state‐of‐the‐art and remaining challenges with respect to generating input values for computational analysis of mass and momentum transport processes within tissue cultures. It gives an overview on relevant aspects of transport processes in tissue cultures as well as modelling and computational tools to tackle these problems. Further focus is on techniques used for the determination of cell‐specific parameters and characterization of culture systems, including sensors for on‐line determination of relevant parameters. In conclusion, tissue culture techniques are well‐established, and modelling tools are technically mature. New sensor technologies are on the way, especially for organ chips. The greatest remaining challenge seems to be the proper addressing and handling of input parameters required for mathematical models. Following Good Modelling Practice approaches when setting up and validating computational models is, therefore, essential to get to better estimations of the interesting complex processes inside organotypic tissue cultures in the future. [ABSTRACT FROM AUTHOR]

Equilibrium thermodynamics answers the question, “by how much?” Nonequilibrium thermodynamics answers the question “how fast?” The physicochemical mechanics approach presented in this article answers both of these questions. It also gives equilibrium laws and expressions for all major transport coefficients and their relations, which was previously impossible. For example, Onsager’s reciprocal relations only tell us that symmetric transport coefficients are equal, and even for these, the value is often not known. Our new approach, applicable to non-isolated systems, leads to a new formulation of the second law of thermodynamics and agrees with entropy increase in spontaneous processes for isolated systems. Instead of entropy, it is based on a modified Lagrangian formulation which always increases during system evolution, even in the presence of external fields. This article will present numerous examples of physicochemical mechanics can be applied to various transport processes and their equilibriums, including thermodiffusion and different surface processes. It has been proven that the efficiency of a transport process with an actual steady-state flux (as opposed to a reversible process near equilibrium) is 50%. Finally, an analogy between physicochemical mechanics and some social processes is mentioned.

The design of a gas diffusion layer (GDL) is an effective way to manage water transport, thus improving the performance of air-cooled fuel cells. In the present study, three group designs of GDL with polytetrafluoroethylene (PTFE)—uniformly doped, in-planed sandwich doped and through-plane gradient doped—are proposed, and their effects on the performance of air-cooled fuel cells are explored by numerical simulation. The distribution of key physical quantities in the cathode catalyst layer (CCL), current density and the uniformity of current density distribution in the CCL were analyzed in detail. The results show that properly reducing the amount of PTFE in GDL is beneficial to promoting the water retaining capacity of air-cooled fuel cells, and then improving the performance of fuel cells. The performance of the in-plane sandwich GDL design cannot exceed the design with 10% PTFE uniformly doped, and this design will aggravate the uneven distribution of current density in CCL. Compared with the design of GDL with 40% PTFE uniformly doped, the current density can be improved by 22% when operating at 0.6 V by gradient increasing the PTFE content in GDL from the GDL/MPL interface to the gas channel. Furthermore, this design can maintain as good a current density uniformity as uniformly doping schemes. [ABSTRACT FROM AUTHOR]

The aim of the work is to analyze the existing and used methods of direct molecular modeling of physical processes and phenomena. In particular, methods of molecular dynamics, Brownian dynamics, direct statistical Monte Carlo modeling, and stochastic molecular modeling are discussed. In all cases, the main features of these methods, the accuracy of modeling and development perspectives are analyzed. Examples of solving original problems, in particular, modeling of gas transport coefficients in the bulk and nanochannels are considered. [ABSTRACT FROM AUTHOR]

In this work, we present mixed dimensional models for simulating blood flow and transport processes in breast tissue and the vascular tree supplying it. These processes are considered, to start from the aortic inlet to the capillaries and tissue of the breast. Large variations in biophysical properties and flow conditions exist in this system necessitating the use of different flow models for different geometries and flow regimes. In total, we consider four different model types. First, a system of 1D nonlinear hyperbolic partial differential equations (PDEs) is considered to simulate blood flow in larger arteries with highly elastic vessel walls. Second, we assign 1D linearized hyperbolic PDEs to model the smaller arteries with stiffer vessel walls. The third model type consists of ODE systems (0D models). It is used to model the arterioles and peripheral circulation. Finally, homogenized 3D porous media models are considered to simulate flow and transport in capillaries and tissue within the breast volume. Sink terms are used to account for the influence of the venous and lymphatic systems. Combining the four model types, we obtain two different 1D–0D–3D coupled models for simulating blood flow and transport processes: The first model results in a fully coupled 1D–0D–3D model covering the complete path from the aorta to the breast combining a generic arterial network with a patient specific breast network and geometry. The second model is a reduced one based on the separation of the generic and patient specific parts. The information from a calibrated fully coupled model is used as inflow condition for the patient specific sub‐model allowing a significant computational cost reduction. Several numerical experiments are conducted to calibrate the generic model parameters and to demonstrate realistic flow simulations compared to existing data on blood flow in the human breast and vascular system. Moreover, we use two different breast vasculature and tissue data sets to illustrate the robustness of our reduced sub‐model approach. [ABSTRACT FROM AUTHOR]

A novel method based on cup‐mixing concentration and superficial velocity is presented for the analysis of reactions in isothermal fixed‐bed reactors. It is founded on experimentally observed profiles of concentration and velocity so as to preserve the heterogeneity of a reaction system. The domain of application of the model includes reaction systems at lower Reynolds numbers and Péclet numbers of less than 700 with a void fraction of ϕ for which the ratio of the bed‐length‐to‐particle diameter to particle Péclet number exceeds 0.3ϕ1−ϕ. [ABSTRACT FROM AUTHOR]

In the present work, we study heat transport through a one dimensional time-dependent nanomechanical system. The microscopic model consists of coupled chains of atoms, considering local and non-local interactions between particles. We show that the system presents different stationary transport regimes depending on the driving frequency, temperature gradients and the degree of locality of the interactions. In one of these regimes, the system operates as a phonon refrigerator, and its cooling performance is analyzed. Based on a low frequency approach, we show that non-locality and its interplay with dissipation cause a decrease in cooling capacity. The results are obtained numerically by means of the Keldysh non-equilibrium Green’s function formalism. [ABSTRACT FROM AUTHOR]

The existence of various native or nonnative species/fluids, along with having more than one phase in the subsurface and within the integrated production and injection systems, generates unique challenges as the pressure, temperature, composition and time (P-T-z and t) domains exhibit multi-scale characteristics. In such systems, fluid/component mixing, whether for natural reasons or man-made reasons, is one of the most complex aspects of the behavior of the system, as inherent compositions are partially or all due to these phenomena. Any time a gradient is introduced, these systems try to converge thermodynamically to an equilibrium state while being in the disequilibrium state at scale during the transitional process. These disequilibrium states create diffusive gradients, which, in the absence of flow, control the mixing processes leading to equilibrium at a certain time scale, which could also be a function of various time and length scales associated with the system. Therefore, it is crucial to understand these aspects, especially when technologies that need or utilize these concepts are under development. For example, as the technology of gas-injection-based enhanced oil recovery, CO2 sequestration and flooding have been developed, deployed and applied to several reservoirs/aquifers worldwide, performing research on mass-transfer mechanisms between gas, oil and aqueous phases became more important, especially in terms of optimal design considerations. It is well-known that in absence of direct frontal contact and convective mixing, diffusive mixing is one of most dominant mass-transfer mechanisms, which has an impact on the effectiveness of the oil recovery and gas injection processes. Therefore, in this work, we review the fundamentals of diffusive mixing processes in general terms and summarize the theoretical, experimental and empirical studies to estimate the diffusion coefficients at high pressure—temperature conditions at various time and length scales relevant to reservoir-fluid systems. [ABSTRACT FROM AUTHOR]

Processes of intracellular and extracellular transport play one of the most important roles in the functioning of cells. Changes to transport mechanisms in a neuron can lead to the disruption of many cellular processes and even to cell death. It was shown that disruption of the processes of vesicular, axonal, and synaptic transport can lead to a number of diseases of the central nervous system, including Parkinson's disease (PD). Here, we studied changes in the expression of genes whose protein products are involved in the transport processes (Snca, Drd2, Rab5a, Anxa2, and Nsf) in the brain tissues and peripheral blood of mice with MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)-induced models of PD. We detected changes in the expressions of Drd2, Anxa2, and Nsf at the earliest modeling stages. Additionally, we have identified conspicuous changes in the expression level of Anxa2 in the striatum and substantia nigra of mice with MPTP-induced models of PD in its early stages. These data clearly suggest the involvement of protein products in these genes in the earliest stages of the pathogenesis of PD. [ABSTRACT FROM AUTHOR]

Oxygen (O2) is the ultimate oxidant on Earth and its respiration confers such an energetic advantage that microorganisms have evolved the capacity to scavenge O2 down to nanomolar concentrations. The respiration of O2 at extremely low levels is proving to be common to diverse microbial taxa, including organisms formerly considered strict anaerobes. Motivated by recent advances in O2 sensing and DNA/RNA sequencing technologies, we performed a systematic review of environmental metatranscriptomes revealing that microbial respiration of O2 at nanomolar concentrations is ubiquitous and drives microbial activity in seemingly anoxic aquatic habitats. These habitats were key to the early evolution of life and are projected to become more prevalent in the near future due to anthropogenic-driven environmental change. Here, we summarize our current understanding of aerobic microbial respiration under apparent anoxia, including novel processes, their underlying biochemical pathways, the involved microorganisms, and their environmental importance and evolutionary origin. [ABSTRACT FROM AUTHOR]

We reassess the ‘dispersionless transport regime’ of Brownian particles in tilted periodic potentials. We show that the particles exhibit normal diffusive motion right after transitioning into the running state dragged by the constant bias force. No special transient dynamics appears, contrary to conjectures in the previous studies. The observed flat segment in the dispersion evolution curve is solely due to the broad spatial distribution of particles formed in the early superdiffusion stage. We quantitatively describe the whole evolution of the distribution function during superdiffusion and the transition to the normal diffusion that follows, in the framework of the two-well potential in the velocity space model. We show that the superdiffusion exponent is α = 3. The duration of the ostensible ‘dispersionless regime’ is derived analytically. It is shown to diverge exponentially as the temperature decreases to zero. [ABSTRACT FROM AUTHOR]

Edit Objectives The use of Unmanned Vehicles in air, land and water transport is constantly increasing due to their technical and operational capabilities, along with economic advantages. They are used for recreational and commercial purposes by individuals, companies, organisations and state institutions. Particular types of vehicles are at different stages of technical, legislative and implementation advancement. Unmanned vehicles are at different phases of the process of the launch on the market for common use by the public. Railway transport will be the first to undergo widespread and, consequently, full automation, due to the fact that it is already in use and there is a possibility of its safe implementation, which must progress along with the development of technology, science and experience of producers and users. Methods Scientific methods used in the paper are: analysis and criticism of written sources, analysis and logical construction. Results The article presents issues concerning the possibility of implementing the use of unmanned vehicles in the air, land and water transport system. The state of advancement of the legislative and technical work has been described, along with the difficulties that can be encountered before the complete implementation of unmanned vehicles into operation Conclusions The process of implementing unmanned vehicles into the transport system has begun and it is irreversible. It is a matter of time before unmanned systems are used to transport people and goods. Their use is safer, more economically beneficial and brings benefits to society.

We develop an effective numerical scheme to capture hydrodynamic (HD) modes in general classical anharmonic chains. This scheme is based on the HD theory suggested by Ernstâ€"Haugeâ€"van Leeuwen, which takes full role of pressure fluctuations into account. With this scheme we show that the traditional pictures given by the current nonlinear fluctuating HD theory are valid only when the system’s pressure is zero and the pressure fluctuations are weak. For nonvanishing pressure, the HD modes can, however, respond to small and large pressure fluctuations and relax in some distinct manners. Our results shed new light on understanding thermal transport from the perspective of HD theory. [ABSTRACT FROM AUTHOR]

The Nyexon Rock Avalanches in the southern Qinghai-Tibet Plateau is a huge scale earthquake-induced slope disaster in the Holocene, the accumulation area has distinct sedimentological characteristics, which is of great significance for studying the intrusion and restraint mechanism during long-distance transportation of large rock avalanches or debris avalanche. This long-distance transportation induced a series of landform types, such as ridges, hills, and ravines; they are widely distributed in all areas and extensively developed shear zones, jigsaw cracks, and other structures within the sedimentary structure. With the analysis of DEM data and geological survey, two main types of basement structures and their transition relationships are distinguished; they play an essential role in the restraining bottom during rock avalanches. In the sedimentary structure, the block facies and mixing facies occupy the main body of the deposition from the center to the distal area. Under the basement restriction, mixing facies are formed between the bottom of the sedimentary layer and the basement sedimentary structure; the shear band is mainly developed along with the mixing facies and basement facies, which is accompanied by basement liquefaction and rheology. A sedimentary facies model is established based on the sedimentary structure sequence of the Nyexon Rock Avalanches transportation. After analyzing the failure mechanism of the rock avalanches, it is believed that in the initial stage of failure, the rock avalanches is transformed into a particle flow that is similar to the debris avalanche, which is restrained by the basement structure and lateral bound; then, an accumulated obstacle highland is formed in the central area after deceleration, making the transportation of the main fluid to deflect quickly.

This article is aimed at introducing the issue of simulating traffic processes and the possibility of creating traffic models using software solutions. The introduction describes the basic problems that are present for the responsible authority in the decision-making process on the implementation of transport infrastructure projects and the verification of the validity of their implementation. The importance of computer technology in the process of evaluating projects and the socioeconomic effects they bring is also mentioned. The benefits of retrospective evaluation of already implemented projects and comparison with predictions made in the preparation process in relation to the verification of forecasts and the structure and scope of input data are also indicated. In the next part, the starting points for the creation of traffic models, input data and expected outputs are summarized due to the nature of the performed simulation. The final part provides an overview of the possibilities of using software solutions for the creation of traffic models and the suitability of their application according to the specifics of the simulation and output requirements. [ABSTRACT FROM AUTHOR]

Organic semiconductors are intrinsic randomly inhomogeneous materials where charge transport occurs by hopping of the carriers between localized sites having a distribution of energy levels. However, the average carrier density seems to be accurately described by a simple drift-diffusion equation. We investigate the reasons for the effectiveness of the drift-diffusion model in a random material and show that the key assumption for its validity is that the correlation lengths of the randomly perturbed coefficients are much smaller than any other characteristic length of the problem. As a byproduct, we find how the effective drift and diffusion coefficients depend on the randomness. [ABSTRACT FROM AUTHOR]

Today, one of the main important tasks is to analyze the states of achievement related to the required levels for marine passenger terminals and their route networks, depending on the influence of the external environment (based on the discretization of processes). This proposal is relevant both to increase the passenger traffic and to change the route network of ferry lines. There is an uneven congestion of individual directions of ferry lines and passenger terminals, which determines the need to select a finite number of states for the efficient operation of the «passenger terminalferry line» system. For the research of changes and assessments, it is proposed to use the process discretization methodology and the formation of a new circos plot intensity diagram. This study focuses on the passenger terminals in the Adriatic Sea and the existing route network in this region. As a result of the analysis, a set of points in time are selected that are characterized by various intensities and passenger traffic. For the selected set of values, a set of new intensity circos plot diagrams are constructed. On their basis, it is possible to analyze the mutual influence of the passenger terminals on each other to analyze the ferry transportation market and the number of shipping companies on it. New scientific approach can improve the quality of research and decision-making process for research of the «passenger terminal-ferry line» system. The practical results we can see in the form of circos plot diagrams for sea passenger transportation in the Adriatic Sea region and the proposed research methodology for research and operation analysis of the «ferry line - marine passenger terminal» system based on process discretization.

According to statistics, the marine passenger transportation sectors (both cruise lines and ferry lines) show a significant increase of passenger traffic and the intensity of ship routes. But new features of the conditions for passenger traffic growth require the development of new methodological transport models for cruise and ferry networks and new practical forecasting methods. Changes are observed in the fleet composition, mostly in the direction of increased. New approach for forecasting has to be based on the interaction of such systems as «city‒sea passenger port‒cruise and ferry lines». This condition now determines new need to describe the principles and forms of organization of maritime ferry networks and changes under the influence of the external environment. The object of the research is the Baltic Sea region and the existing route networks of cruise and ferry lines. Exploring this system, the usage of new mathematical apparatus based on correspondence matrices and agent-based simulation was justified for estimating the workload on transport infrastructure around the passenger port and for the existing ferry or cruise route network. The practical results of new simulation model, on the one hand, justify the need for a comprehensive study of the conditions for the formation of ferry and cruise route networks in changing conditions. On the other hand, these new results could improve the quality of decision-making process in forecasting the route network on the basis of the research of passenger traffic between systems «city‒sea terminal‒cruise line or ferry line».

The design of a gas diffusion layer (GDL) is an effective way to manage water transport, thus improving the performance of air-cooled fuel cells. In the present study, three group designs of GDL with polytetrafluoroethylene (PTFE)—uniformly doped, in-planed sandwich doped and through-plane gradient doped—are proposed, and their effects on the performance of air-cooled fuel cells are explored by numerical simulation. The distribution of key physical quantities in the cathode catalyst layer (CCL), current density and the uniformity of current density distribution in the CCL were analyzed in detail. The results show that properly reducing the amount of PTFE in GDL is beneficial to promoting the water retaining capacity of air-cooled fuel cells, and then improving the performance of fuel cells. The performance of the in-plane sandwich GDL design cannot exceed the design with 10% PTFE uniformly doped, and this design will aggravate the uneven distribution of current density in CCL. Compared with the design of GDL with 40% PTFE uniformly doped, the current density can be improved by 22% when operating at 0.6 V by gradient increasing the PTFE content in GDL from the GDL/MPL interface to the gas channel. Furthermore, this design can maintain as good a current density uniformity as uniformly doping schemes.

A pathologically formed blood clot or thrombus is central to major cardiovascular diseases like heart attack and stroke. Detailed quantitative evaluation of flow and flow-mediated transport processes in the thrombus neighborhood within large artery hemodynamics is crucial for understanding disease progression and assessing treatment efficacy. This, however, remains a challenging task owing to the complexity of pulsatile viscous flow interactions with arbitrary shape and heterogeneous microstructure of realistic thrombi. Here, we address this challenge by conducting a systematic parametric simulation-based study on characterizing unsteady hemodynamics and flow-mediated transport in the neighborhood of an arterial thrombus. We use a hybrid particle—continuum-based finite element approach to handle arbitrary thrombus shape and microstructural variations. Results from a cohort of 50 different unsteady flow scenarios are presented, including unsteady vortical structures, pressure gradient across the thrombus boundary, finite time Lyapunov exponents, and dynamic coherent structures that organize advective transport. We clearly illustrate the combined influence of three key parameters—thrombus shape, microstructure, and extent of wall disease—in terms of: (a) determining hemodynamic features in the thrombus neighborhood and (b) governing the balance between advection, permeation, and diffusion to regulate transport processes in the thrombus neighborhood. [ABSTRACT FROM AUTHOR]

This paper offers a novel application of our model worked out in Maple environment to help understand the very complex transport processes in horizontal subsurface flow constructed wetland with coarse gravel (HSFCW-C). We made tracer measurements: Inside a constructed wetland, we had 9 sample points, and samples were taken from each point at two depths. Our model is a divided convective-dispersive transport (D-CDT) model which makes a fitted response curve from the sum of two separate CDT curves showing the contributions of the main and side streams. Analytical solutions of CDT curves are inverse Gaussian distribution functions. This model was fitted onto inner points of the measurements to demonstrate that the model gives better fitting to the inner points than the commonly used convective-dispersive transport model. The importance of this new application of the model is that it can resemble transport processes in these constructed wetlands more precisely than the regularly used convective-dispersive transport (CDT) model. The model allows for calculations of velocity and dispersion coefficients. The results showed that this model gave differences of 4–99% (of velocity) and 2–474% (of dispersion coefficient) compared with the CDT model and values were closer to actual hydraulic behavior. The results also demonstrated the main flow path in the system. [ABSTRACT FROM AUTHOR]

Processes of intracellular and extracellular transport play one of the most important roles in the functioning of cells. Changes to transport mechanisms in a neuron can lead to the disruption of many cellular processes and even to cell death. It was shown that disruption of the processes of vesicular, axonal, and synaptic transport can lead to a number of diseases of the central nervous system, including Parkinson’s disease (PD). Here, we studied changes in the expression of genes whose protein products are involved in the transport processes (Snca, Drd2, Rab5a, Anxa2, and Nsf) in the brain tissues and peripheral blood of mice with MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)-induced models of PD. We detected changes in the expressions of Drd2, Anxa2, and Nsf at the earliest modeling stages. Additionally, we have identified conspicuous changes in the expression level of Anxa2 in the striatum and substantia nigra of mice with MPTP-induced models of PD in its early stages. These data clearly suggest the involvement of protein products in these genes in the earliest stages of the pathogenesis of PD.

This study has been performed for a 2-D fluid model of sodium photoplasma with noble gas mixtures in two-chamber cells. A source of photoexcitation of sodium resonance levels is located in the first (source) chamber. In contrast, plasma in the second (diffusion) chamber is formed due to the transport of charges from the first chamber. The created photoplasma at different excitation rate, gas type, and pressure have been studied. Unlike previous investigations of photoplasma based on the study of the temporal and spatial distributions of plasma parameters, in this research, the transport processes also have been investigated explicitly. The different flux components throughout the cell and the corresponding variations of electron temperature gradient affect the fluxes magnitude and, consequently, the electromotive force (EMF). Generally speaking, the findings from the model contribute to that, for the optimization of photoplasma cells, the study of transport processes must be focused. [ABSTRACT FROM AUTHOR]

We worked out a method in Maple environment to help understand the difficult transport processes in horizontal subsurface flow constructed wetlands filled with coarse gravel (HSFCW-C). With this process, the measured tracer results of the inner points of a HSFCW-C can be fitted more accurately than with the conventionally used distribution functions (Gaussian, Lognormal, Fick (Inverse Gaussian) and Gamma). This research outcome only applies for planted HSFCW-Cs. The outcome of the analysis shows that conventional solutions completely stirred series tank reactor (CSTR) model and convection-dispersion transport (CDT) model do not describe the internal transport processes with sufficient accuracy. This study may help us develop better process descriptions of very complex transport processes in HSFCW-Cs. Our results also revealed that the tracer response curves of planted HSFCW-C conservative inner points can be fitted well with Frechet distribution only if the response curve has one peak. [ABSTRACT FROM AUTHOR]

. Modern transport systems are characterized by the development and implementation of intelligent transport technologies. Today, dynamic forecast models are not used in practice in the operation of a passenger terminal. Decision making is based on some regulatory values for passenger traffic, but this is not sufficient for efficient terminal management. Modern passenger terminals are characterized by dynamic process variability and consideration of diverse options, taking into account the criteria of safety, reliability analysis, and the continuous research of passenger processing. For any modern marine passenger terminal, it is necessary to use the tool to simulate passenger flows in dynamics. Only in this way it is possible to obtain the analytical information and use it for decision making when solving the problem of the amount of personnel required for passenger service, transport safety, some forecasting tasks and so on. Of particular relevance is the choice of the mathematical transport model and the practical conditions for the implementation of the model in the real terminal operation. In this article, the analysis technique of intelligent simulation-based terminal services provides a new mathematical model of passenger movement inside the terminal and presents a new software instrument. Moreover, the conditions of implementation of some transportation models during the operation of marine passenger terminal are examined. The study represents an example of analytical information used for the forecast of the terminal operations, the analysis of the workload and the efficiency of the organization of the marine terminal.

Alzheimer's disease is investigated using a thermodynamic approach based on ion fluxes across the neuronal membrane. Our study indicates that the onset of Alzheimer's may be aided by a hyperpolarization of this membrane, because hyperpolarization-activated cyclic nucleotide gated HCN channels 1–4 conduct inward, with the consequence of depolarising Na + /K + currents which in turn impacts synaptic transmission and reduces plasticity. [ABSTRACT FROM AUTHOR]

Foam formation in porous media is a topic of growing scientific and industrial interest due to its range of applications, from daily life consumer products to oil recovery. Despite the work done so far on foams flowing through complex structures, such as rigid porous media, this subject still needs to be fully elucidated. An additional complexity to the problem arises when the porous medium is deformable, a situation which has only been faced, to our knowledge, from a modelling point of view. In this work, the investigation of foam formation in deformable porous media is carried out by using commercial sponges as a deformable porous media system, with special emphasis on the effect of confinement on foam bubble size distribution. Foam is formed by wetting the sponge with an aqueous surfactant solution and then squeezing the sponge either between two glass cover slides or between a plastic net and a cover slide. Our experimental data reveal that the latter system allows the formation of drier foams (ie, with lower liquid fraction, fL < 0.3), more similar to the ones obtained in dish‐washing applications. Moreover, the effect of sponge type, in terms of material and microstructure, on final foam is presented. Our results are of potential interest for the optimization of foams in complex structures, such as in deformable porous media. [ABSTRACT FROM AUTHOR]

In this paper we present a numerical solution of a one-dimensional anomalous subdiffusion equation with a variable diffusion coefficient. The proposed method is an extension of the fractional Crank-Nicolson method for a subdiffusion equation with constant diffusion coefficient. The work of the proposed algorithm is illustrated by the results of numerical simulations. [ABSTRACT FROM AUTHOR]

The polarization processes in thin layers of amorphous molybdenum disulfide MoS2 are studied by dielectric spectroscopy techniques. The process of dipole-relaxation polarization is observed. The microscopic parameters of the system are calculated, and the relaxation time of the dipole-polarization process, as well as the activation energies Ea and Eσ of the relaxation process and conductivity, respectively, are determined. The fact that the two activation energies are close to each other suggests that the processes of relaxation and charge transport are driven by the same mechanism. [ABSTRACT FROM AUTHOR]

This review contains the most important results obtained by Russian scientists in studying atmospheric ozone in 2015–2018 and is a part of the Russian National Report on Meteorology and Atmospheric Sciences that was prepared for the International Association of Meteorology and Atmospheric Sciences (IAMAS). This report was considered and approved at the 27th General Assembly of the International Union of Geodesy and Geophysics (IUGG). A list of main Russian publications on atmospheric ozone and its precursors is appended to it. [ABSTRACT FROM AUTHOR]