Solute Transport Research Articles

An analytical investigation into solute transport and sorption via intra-particle diffusion in the dual-porosity limit

We develop a mathematical model for adsorption based on averaging the flow around, and diffusion inside, adsorbent particles in a column. The model involves three coupled partial differential equations for the contaminant concentration both in the carrier fluid and within the particle as well as the adsorption rate. The adsorption rate is modelled using the Sips equation, which is suitable for describing both physical and chemical adsorption mechanisms. Non-dimensionalisation is used to determine the controlling parameter groups as well as to determine negligible terms and so reduce the system complexity. The inclusion of intra-particle diffusion introduces new dimensionless parameters to those found in standard works, including a form of internal Damköhler number and a new characteristic time scale. We provide a numerical method for the full model and show how in certain situations a travelling wave approach can be utilized to find analytical solutions. The model is validated against published experimental data for the removal of Mercury(II) and CO2. The results show excellent agreement with measurements of column outlet contaminant concentration and provide insights into the underlying chemical reactions.

Influence of the in-stream structures and parameters variation on transient storage

In-stream structures are designed to mimic natural topographic features in rivers and have emerged as an effective method for ecological restoration in recent years. However, there is a lack of studies exploring the impact of these structural designs on transient storage characteristics. We implemented a series of weirs and groynes in a stream and conducted conservative tracer experiments to quantify the influence of these structures on solute transport within the stream. Additionally, we utilized the one-dimensional transport with inflow and storage (OTIS) solute diffusive transport model to assess variations in solute transport parameters and characterize transient storage. Our analysis of the OTIS parameters and transient storage index revealed that in-stream structures can enhance the interaction between flowing water in the mainstem area and the transient storage area, consequently improve the stream's transient storage capacity. Notably, weirs had a greater effect on the transient storage characteristics of streams parameters than groynes. Furthermore, the effect of this impact intensified with an increase in the number, spacing, and height of the in-stream structures. However, it was observed that the coupling between the structures decreased simultaneously, resulting in a gradual weakening of the enhancement in transient storage capacity. This study deepens our understanding of how the design factors of in-stream structures influence transient storage characteristics, and provides a theoretical basis for optimizing in-stream structures in ecological restoration projects.

Investigating the phase diagram-ionic conductivity isotherm relationship in aqueous solutions of common acids: hydrochloric, nitric, sulfuric and phosphoric acid

The relationship between phase diagram features around the solid–liquid equilibrium region and ionic conductivity in aqueous solutions is not well understood over the whole concentration range as is the case for acidic aqueous solutions. In this work, we have studied the ionic conductivity (κ) as a function of molar fraction (x) and temperature (T) for four acid/water solutions namely, monoprotic hydrochloric acid (HCl) and nitric acid (HNO3), diprotic sulfuric acid (H2SO4) and triprotic phosphoric acid (H3PO4) along with their binary phase diagrams. The connection between the main features of the phase diagrams and the trends in the ionic conductivity isotherms is established with a new insight on the two pertinent dominant conductivity mechanisms (hopping and vehicular). Ionic conductivity at different temperatures were collected from literature and fitted to reported isothermal (κ vs. x) and iso-compositional (κ vs. T) equations along with a novel semi-empirical equation (κ = f (x, T)) for diprotic and triprotic acids. This equation not only has the best fit for acids with different valency; but also contains four parameters, less than any other similar equation in literature. This work is one of few that advances the understanding of the intricate relationship between structure and ionic transport in various acidic aqueous solutions.

Soil structure and solute transport pathways in biogas digestate-amended soils

Here, we investigated the effects of biogas digestate application on flow pathways and soil properties in a sandy soil aiming at unraveling phosphorus accumulation and depletion processes in fertilized soils. Dye tracer experiments were conducted to visualize and distinguish between various flow pathways, while X-ray tomography was utilized to characterize the soil structure. The dye tracer experiments revealed differences between the control and the digestate-treated group of soil profiles in the top-soils although no statistical verification was possible amid a single plot per treatment. The stained soil profiles in both treatments indicate extensive areas of homogeneous and heterogeneous matrix flow. However, the digestate-treated group showed a decrease in homogeneous matrix flow and a notable presence of preferential flow with low interaction. The application of biogas digestate impacted various soil properties, including organic carbon content, water drop penetration time, and pH levels. Accordingly, the topsoil experienced an increase in soil organic carbon, water repellency, and a decrease in pH levels. The fraction of macropores also increased in the topsoil of the digestate-treated group, accompanied by an increase in tortuosity.Double lactate-extractable phosphorus (DL-P) distribution varied across the different flow pathways, with higher concentrations detected in matrix flow and a depletion observed in preferential flow regions in both treatments. These findings confirm the close relationship between the type of flow pathway and phosphorus distribution in soils. Additionally, a significant correlation was observed between pH levels and DL-P in the digestate-treated group, indicating potential implications for phosphorus availability. Overall, the results of this study suggest that the long-term application of biogas digestate is likely to improve soil properties as related to soil organic matter content, particularly in the topsoil of sandy soils. The study highlights the significance of the prevailing flow and transport pattern on nutrient distribution, with potential implications for nutrient management in agricultural systems. While the study design presented prevents the unequivocal assignment of differences to treatment effects, our data likely illustrate the impacts of biogas digestate amendment on the investigated sandy soil.Further research should focus on assessing the long-term effects of digestate application in loamy and clayey soils.

Smart and Sustainable Public Transportation - A Need of Developing Countries

A sustainable transport system is one which offers economical solutions and causes no/little damage to the environment. We usually categorize transport into three sections - roads, airways and water. Such systems need to be set up in order to have a transportation medium or ecosystem with minimum environmental impact. Public buses are an excellent example of sustainable road transportation. They can accommodate a large number of people economically and help ease the financial burden on individuals. Unfortunately, the majority of public buses are powered by non-renewable energy sources such as diesel. This results in the release of hazardous pollutants, leading to a degraded environment. Although the cost of using this form of transportation is relatively affordable, it nonetheless has an adverse effect on the environment. Therefore, it cannot be considered sustainable in that regard. We are constantly pushing the boundaries of innovation by introducing new technologies such as IoT, AI, Blockchain and 5G into our smart and sustainable transportation system. This way we can ensure its sustainability from all angles. The impact of transportation on our society is undeniable- both in terms of economic, social and environmental implications. To ensure a better quality of life for all, we must shift to smart and sustainable transport solutions. This research seeks to present a clever and eco-friendly transport system that brings economic and social advantages for developing countries.

Numerical study on magnetic control of boundary layers in non-Newtonian flows over stretching cylinders using Keller box analysis

This article presents an analysis of the magnetic field’s effects on two-dimensional, two-directional, incompressible, and steady third-grade fluid flow over a stretched circular cylinder. A mathematical model describing the behavior of third-grade fluid in the cylindrical coordinate system is developed, accounting for nonlinear differential conditions. To simplify the analysis, appropriate transformations are applied to convert the fractional differential conditions into ordinary differential conditions. The resulting nonlinear differential framework is solved using the Keller Box method. The influences of several novel parameters on the velocity are depicted and examined. Furthermore, the expression for the skin-friction coefficient is computed and provided. The comparison of the obtained results with existing literature is made and found in good accordance. Through comprehensive numerical simulations and analytical derivations, this study contributes to the understanding of magnetic field control in boundary layers of third-grade fluid over stretching cylinders, with implications for a wide range of practical applications in engineering and fluid dynamics. The stronger influence of the magnetic field, indicating an increase in the Hartmann number, corresponds to suppression of thermal and solutal transport, thereby leading to a decrease in the temperature and concentration gradients. Conversely, the velocity profile exhibits an increase, indicating enhanced fluid motion under the influence of the magnetic field. This behavior is consistent with the magnetohydrodynamic effects, where the Lorentz force induced by the magnetic field alters the fluid flow, resulting in changes in the velocity distribution while impacting temperature and concentration gradients.

Mass transfer of solute in an oscillating flow in a two-dimensional channel

The effective diffusion of a solute in a rectangular two-dimensional channel is experimentally studied. We experimentally examine the effective diffusion of Rhodamine B dissolved in water oscillating in a rectangular Hele–Shaw cell. The concentration of Rhodamine B in water is measured by the intensity of its fluorescence emission. In particular, we consider two problems: (i) effective diffusion of solute in water oscillating in a two-dimensional rectangular channel (Hele–Shaw cell) and (ii) effective diffusion of solute in pores between monosized hard spheres randomly packed in a rectangular Hele–Shaw cell. It is revealed that the rate of solute mass transfer exceeds the molecular diffusion rate in both cases. It has been demonstrated that when water oscillates between parallel walls, diffusion is accelerated by Taylor dispersion with the effective diffusion coefficient Deff exceeding the molecular diffusion coefficient Dm by 1–2 orders of magnitude. The effective diffusion coefficient Deff depends only on the relative amplitude but not on the frequency of the fluid oscillations in the studied range of frequencies and amplitudes. When the fluid oscillates in the pores of the porous medium, solute transport is faster than in the case of Taylor dispersion. Here, the effective diffusion coefficient depends on both the frequency and amplitude of oscillations. The analysis shows that the experimental data obtained at various frequencies and amplitudes of oscillations are consistent with the relation Deff/Dm∼Pe2 (Pe is the Peclet number). We suggest that the enhanced solute mass transfer is associated with the time-averaged fluid flows that arise due to spatial heterogeneity of the amplitude of water oscillations in the pores between randomly packed hard spheres.

Thermal and solutal transport by Cattaneo-Christov model for the magnetohydrodynamic Williamson fluid with joule heating and heat source/sink

This article scrutinizes the 2-dimensional and boundary layer flow of magnetohydrodynamic Williamson fluid flowing on a stretchable surface with variable viscosity. The thermal and solutal rates are examined through the Cattaneo-Christov model with Joule heating, heat source/sink, and chemical reaction. The authors are motivated to conduct this study because of its practical and scientific significance in various processes, including polymer processing, textile industries, food industries, solar energy, biomedical science, wind turbine blades, oil spill clean-up, metal rolling, and forging. With the mentioned assumptions, the partial differential equations are achieved by using the basic governing laws, including momentum law, energy law, and concentration law. This non-linear system of equations is transmuted into ordinary differential equations by taking similarity transformations. The main novelty behind the conduction of this work is the numerical technique, namely the ‘Adams-Milne (Predictor-Corrector)’ method along with the Runge-Kutta technique on Matlab software, which has not previously been studied by any researcher in the literature. The analytical solution of the determined equations is not possible due to their highly non-linear nature; therefore the multistep numerical method namely the ‘Adams-Milne (Predictor-Corrector)’ method, along with the Runge-Kutta technique is used to determine the numerical results. The outcomes are noted due to numerous parameters for velocity, temperature, and concentration profiles. The explanation of graphical and numerical results is discussed here. The graphical impression of the Williamson parameter reveals that the velocity and temperature curves diminish for higher inputs of this parameter. The movement of fluid shows the declining behavior for the Hartmann number and viscosity parameter. The solutal and thermal findings due to Cattaneo-Christov heat and mass relaxation coefficients mark the reducing behaviour in respective field. The rise in reaction coefficient decreases the mass distribution. The analyses of comparison of results are also presented here.

Modeling Solute Transport in Sprinkler Irrigation Laterals

Modeling Solute Transport in Sprinkler Irrigation Laterals

Anomalous Pressure Diffusion and Deformation in Two‐ and Three‐Dimensional Heterogeneous Fractured Media

AbstractIn fractured and stress‐sensitive reservoirs and aquifers, hydromechanical coupling is important, in connection with their heat and solute transport properties, and because the fluid production or extraction leads to land subsidence and potentially to induced seismicity. Classical dual‐porosity poroelasticity (DPP) models cannot upscale pressure diffusion and deformation in fractured porous media, which are characterized by anomalous behaviors that manifest in strong tailing in the temporal evolution of flow rate and subsidence. We study these behaviors using detailed numerical simulations of fluid production in naturally fractured formations characterized by multi‐Gaussian distributions of the matrix permeability. We find that the tailing behaviors depend on the permeability contrast between fracture and matrix, on the permeability distribution in the matrix, and on the correlation length. We use a non–equilibrium, multi‐porosity model to quantify the coupled behaviors of anomalous pressure diffusion, fluid flow and deformation. The model is parameterized by medium and fluid properties, which set the characteristic pressure diffusion time scales. It allows to identify the emerging scaling regimes and scaling behaviors of flow rate and subsidence. We propose a model implementation that captures the full anomalous evolution of flow rates and displacements observed in the detailed numerical simulations in terms of the permeability distribution and matrix length scales. The presented results shed new light on the controls of medium heterogeneity and geometry on pressure diffusion, fluid production and subsidence in highly heterogeneous fractured media.

Hydraulic Conductivity of Soils: A Comprehensive Review of the Impacts of Chemicals, Soil Salinity, Organic Matter, and Land Use

The contamination of groundwater by toxic heavy metals, organic compounds, and microbiological contaminants is a significant issue worldwide. To address this problem, various methods have been employed, including in-situ remediation and transporting polluted soil or groundwater for final treatment. This study aims to review the impact of soil heterogeneity on in-situ remediation, with a particular focus on subsurface preferential flow that accelerates solute transport. The study highlights the importance of soil hydraulic conductivity in soil production, ecological health, and water resource management. Soil hydraulic conductivity is influenced by soil structure, moisture content, and chemical exposure. The findings of this study emphasize that sustainable soil management and environmental restoration require an understanding of hydraulic conductivity parameters and the implementation of appropriate management strategies.

Fat mass and obesity-associated protein (FTO) mediated m6A modification of circFAM192A promoted gastric cancer proliferation by suppressing SLC7A5 decay

Gastric cancer (GC) is a common malignant tumor worldwide, especially in East Asia, with high incidence and mortality rate. Epigenetic modifications have been reported to participate in the progression of gastric cancer, among which m6A is the most abundant and important chemical modification in RNAs. Fat mass and obesity-associated protein (FTO) is the first identified RNA demethylase but little is known about its role in gastric cancer. In our study, data from TCGA and clinical samples showed that FTO was highly expressed in gastric cancer tissues. Kaplan–Meier plotter suggested that patients with the high level of FTO had a poor prognosis. In vitro and in vivo experiments confirmed the role of FTO in promoting gastric cancer cell proliferation. Mechanistically, we found that FTO bound to circFAM192A at the specific site and removed the m6A modification in circFAM192A, protecting it from degradation. CircFAM192A subsequently interacted with the leucine transporter solute carrier family 7 member 5 (SLC7A5) and enhancing its stability. As a result, an increased amount of SLC7A5 was on the membrane, which facilitated leucine uptake and activated the mTOR signaling pathway. Therefore, our study demonstrated that FTO promoted gastric cancer proliferation through the circFAM192A/SLC7A5 axis in the m6A-dependent manner. Our study shed new light on the role of FTO in gastric cancer progression.

Integrated Modular Neural Control for Versatile Locomotion and Object Transportation of a Dung Beetle-Like Robot.

Dung beetles can effectively transport dung pallets of various sizes in any direction across uneven terrain. While this impressive ability can inspire new locomotion and object transportation solutions in multilegged (insect-like) robots, to date, most existing robots use their legs primarily to perform locomotion. Only a few robots can use their legs to achieve both locomotion and object transportation, although they are limited to specific object types/sizes (10%-65% of leg length) on flat terrain. Accordingly, we proposed a novel integrated neural control approach that, like dung beetles, pushes state-of-the-art insect-like robots beyond their current limits toward versatile locomotion and object transportation with different object types/sizes and terrains (flat and uneven). The control method is synthesized based on modular neural mechanisms, integrating central pattern generator (CPG)-based control, adaptive local leg control, descending modulation control, and object manipulation control. We also introduced an object transportation strategy combining walking and periodic hind leg lifting for soft object transportation. We validated our method on a dung beetle-like robot. Our results show that the robot can perform versatile locomotion and use its legs to transport hard and soft objects of various sizes (60%-70% of leg length) and weights (approximately 3%-115% of robot weight) on flat and uneven terrains. The study also suggests possible neural control mechanisms underlying the dung beetle Scarabaeus galenus' versatile locomotion and small dung pallet transportation.

The Willingness to Purchase Electric Vehicles: A Comprehensive Review

This paper aims to comprehensively investigate the multifaceted factors influencing consumers’ willingness to purchase electric vehicles (EVs), providing a deeper understanding of the drivers behind EV adoption. The study draws on various scholarly sources to examine the intricate relationships among multiple determinants, including environmental concern, performance expectations, effort expectancy, charging point networks, charging time, price, operational costs, incentives, and attitude toward EVs. These factors are analyzed within a conceptual framework, highlighting the pivotal role of attitude as a mediating variable. The review reveals that environmental concern, driven by awareness of the ecological impact of conventional vehicles, motivates individuals to opt for EVs as a more sustainable mode of transportation. Performance expectations, such as energy efficiency and emission reduction, significantly influence consumer preferences. Effort expectancy, indicating the ease of using EV technology, plays a critical role in adoption decisions. Charging infrastructure, both availability and accessibility, is a crucial facilitator of EV adoption, emphasizing the importance of robust charging networks. Concerns about charging time underscore the need for faster and more convenient recharging methods. Price remains a barrier, with high initial costs, although operational cost advantages make EVs economically appealing. Depending on the region, government incentives have varying effectiveness in reducing financial barriers to EV adoption. Attitude toward EVs, acting as a mediating variable, highlights the importance of positive perceptions in shaping consumer intentions. This study offers a comprehensive review of the interplay of factors influencing EV adoption, providing a holistic view of consumer decision-making in the EV market. It emphasizes the need for further empirical research to validate and extend the proposed model. It offers valuable insights for policymakers, manufacturers, and researchers in promoting sustainable transportation solutions and accelerating EV adoption in response to environmental concerns.

RIDESHARE: An Innovative Way to Commute

Abstract: In the face of escalating urban congestion, rising transportation costs, and mounting environmental concerns, the innovative concept of Ride Share is revolutionising the way people commute. This community-driven approach leverages technology, primarily through smartphone apps and web platforms, to facilitate the sharing of rides among individuals with similar destinations, effectively reducing the number of vehicles on the road. The key benefits of Ride Share include cost efficiency, as participants can significantly cut down on fuel and maintenance expenses, easing the financial burden of daily commuting. This also extends to reducing the demand for costly parking spaces, making it an economically appealing choice. Moreover, Ride Share's route optimization algorithms ensure efficient travel, further reducing time and costs. Beyond the economic advantages, this concept significantly contributes to environmental sustainability by alleviating traffic congestion and lowering greenhouse gas emissions. It aligns with the global push for greener transportation solutions and the fight against climate change. Ride Share represents a paradigm shift in daily transportation, fostering a sense of community and shared responsibility. As it continues to gain popularity, it promises to play a substantial role in creating a more efficient, cost-effective, and eco-friendly future for commuters worldwide.

Optimization of Hybrid Cooling Systems for Automotive Engines: Integrating Radiator and Air Conditioning Efficiency for Enhanced Performance and Energy Efficiency

Abstract: This research paper introduces a groundbreaking exploration into the optimization of hybrid cooling systems within automotive thermal management. The study focuses on seamlessly integrating radiator and air conditioning components to not only enhance engine performance but also achieve unprecedented levels of energy efficiency. In response to the escalating demand for environmentally conscious and fuel-efficient vehicles, the research delves into advanced engineering solutions and innovative technologies that synergize the functions of traditional radiator and air conditioning systems. The core objective is to harmonize these components, redefining the landscape of automotive thermal management and setting the stage for a sustainable and high-performance future. By scrutinizing advancements, addressing challenges, and proposing potential breakthroughs, the paper contributes to the ongoing discourse on the evolution of engine cooling systems. The findings aim to propel the automotive industry toward a new era where optimal engine performance coexists with energy efficiency and environmental responsibility. This research lays the foundation for future developments that promise to reshape the automotive thermal management landscape, aligning with the global shift towards more sustainable and technologically advanced transportation solutions.

Synergetic Effects of Aloe Vera Extract with Trimethylglycine for Targeted Aquaporin 3 Regulation and Long-Term Skin Hydration.

Aquaporin 3 (AQP3) channels are tetrameric membrane-bound channels that facilitate the transport of water and other small solutes across cell membranes in the skin. Decreased AQP3 expression is associated with skin dryness, skin aging, psoriasis, and delayed wound healing. Thus, our study focused on a novel combination based on Aloe barbadensis leaf extract and trimethylglycine for targeted AQP3 regulation in skin keratinocytes and deep skin moisturization. Firstly, a dose-finding cytotoxicity assay of the selected substances was performed with a 2,5-diphenyl-2H-tetrazolium bromide (MTT) indicator on HaCaT cells. The substances' ability to increase the amount of AQP3 in keratinocytes was evaluated in a keratinocyte cell culture by means of ELISA. Additionally, the deep skin hydration effect was confirmed in clinical research with healthy volunteers. According to the results, the maximum tolerated doses providing viability at 70% (MTDs) values for Aloe barbadensis leaf extract and trimethylglycine were 24.50% and 39.00%, respectively. Following the research and development, a complex based on Aloe barbadensis leaf extract and trimethylglycine in a 1:1 mass ratio exhibited a good cytotoxicity profile, with an MTDs value of 37.90%. Furthermore, it was shown that the combination had a clear synergetic effect and significantly increased AQP3 by up to 380% compared to the negative control and glyceryl glucoside (p < 0.001). It was clinically confirmed that the developed shower gel containing Aloe barbadensis leaf extract and trimethylglycine safely improved skin hydration after one use and over 28 days. Thus, this novel plant-based combination has promising potential for AQP3 regulation in the skin epidermis and a role in the development of dermatological drugs for the treatment of skin xerosis and atopic-related conditions.

Investigating energy management of hybrid vehicle technologies to promote sustainable mobility paradigms

Analysing contemporary passenger cars' energy consumption and environmental impacts is a critical research area. This is particularly relevant in urban transport's dynamic and unpredictable environment, where vehicles' fuel consumption and emissions vary considerably. An in-depth understanding of such fluctuations is essential for innovative, efficient, environmentally friendly vehicle technology. In the present research, I investigated a 1.4-litre petrol hybrid vehicle, focusing on its energy supply chain under real-world urban driving conditions. The study focuses on policies that can promote the development of sustainable mobility, improve energy efficiency and reduce environmental pollution. The results can help to optimise hybrid vehicle technologies in an environmentally conscious way and explore possible new avenues for sustainable transport solutions.

Evaluation of an Impulse-Response Emulator for Groundwater Contaminant Transport Modeling.

There is a significant need to develop decision support tools capable of delivering accurate representations of environmental conditions, such as ground and surface water solute concentrations, in a timely and computationally efficient manner. Such tools can be leveraged to assess a large number of potential management strategies for mitigating non-point source pollutants. Here, we assess the effectiveness of the impulse-response emulation approach to approximate process-based groundwater model estimates of solute transport from MODFLOW and MT3D over a wide range of model inputs and parameters, with the goal of assessing where in parameter space the assumptions underlying this emulation approach are valid. The impulse-response emulator was developed using the sensitivity analysis utilities in the PEST++ software suite and is capable of approximating MODFLOW/MT3D estimates of solute transport over a large portion of the parameter space tested, except in cases where the Courant number is above 0.5. Across all runs tested, the highest percent errors were at the plume fronts. These results suggest that the impulse-response approach may be suitable for emulation of solute transport models for a wide range of cases, except when high-resolution outputs are needed, or when very low concentrations at plume edges are of particular interest.

Accelerating autonomous vehicles: Harnessing FPGA power for deep learning advancements

In the rapidly developing field of autonomous vehicles (AV), the integration of deep learning algorithms has become the cornerstone for improving vehicle perception and decision-making ability. This study investigates the potential of field-programmable gate arrays (FPGAs) as hardware accelerators for deep-learning tasks in self-driving cars. This study used a Zynq UltraScale+ MPSoC FPGA board from Xilinx, known for its performance and adaptability, and combined it with a high-resolution camera to simulate real-world visual data encountered by AVs. The approach involved implementing a convolutional neural network (CNN) to perform tasks such as object detection, lane detection, and traffic sign classification. The model was quantized and converted to VHDL code using Xilinx Vivado HLS to optimize the deep learning algorithm for FPGA.The results show that the FPGA-based model significantly outperforms the traditional CPU-based model in terms of processing speed and energy efficiency without sacrificing accuracy. This study highlights the critical role of FPGAs in supporting deep learning tasks in self-driving cars and paves the way for safer and more efficient transportation solutions in the future.