Article
Engineering, Electrical & Electronic
Napoleon Costilla-Enriquez, Yang Weng, Baosen Zhang
Summary: The paper introduces a hybrid first-order and second-order method that effectively avoids being trapped in local minima and demonstrates good performance on standard IEEE benchmarks.
IEEE TRANSACTIONS ON POWER SYSTEMS
(2021)
Article
Engineering, Petroleum
Lishan Yuan, Fujian Zhou, Minghui Li, Xuda Yang, Jiaqi Cheng, Bo Wang
Summary: This paper investigates the transport behavior of diverters during multicluster fracturing and establishes a large-scale experimental system to study diverter transport. The results show that the transport effect of diverters is significantly influenced by different flow distribution among perforations, and the entry of the diverter is only possible when the flow rate of the perforation reaches a certain value. Additionally, the difficulty of the diverter entering the high side of the horizontal wellbore can be overcome by increasing the viscosity of the carrying fluid or using a multidensity mixed diverter. Field case confirmation demonstrates the applicability of the experimentally obtained diverter transport pattern in predicting the location of the diverter and improving temporary plugging.
Article
Thermodynamics
Shayan Davani, Farnaz Rezaei, Arden L. Moore, Niel D. Crews
Summary: The study introduces a novel counter-flow design for stabilizing microfluidic thermal reactors, allowing for precise control of liquid temperature over time. The counter-flow design significantly reduces distortions caused by convection/advection, achieving stable performance under various flow conditions.
APPLIED THERMAL ENGINEERING
(2021)
Article
Geosciences, Multidisciplinary
L. De Oliveira Junior, E. Garel, P. Relvas
Summary: The study examines the characteristics and drivers of Coastal Counter Currents (CCCs) along the South Portugal inner shelf, finding that these currents are primarily influenced by coastal upwelling processes and alongshore pressure gradients, rather than wind conditions. The results suggest a strong correlation between the equatorward flow magnitude before CCCs setup and the subsequent acceleration of CCCs near the bed, indicating the importance of an unbalance in the alongshore pressure gradient for the development of CCCs. Analysis of the depth-averaged momentum equation supports the conclusion that coastal circulation in the region is mainly driven by linear dynamics.
JOURNAL OF MARINE SYSTEMS
(2021)
Article
Chemistry, Multidisciplinary
Sayeed Rushd, Uneb Gazder, Hisham Jahangir Qureshi, Md Arifuzzaman
Summary: The importance of heavy oil in the world oil market has increased due to the decline of light oil reserves. Water-lubricated flow technology may offer a cost-effective solution for the long-distance transport of viscous crudes. The artificial neural network model has shown reliability in predicting friction losses.
APPLIED SCIENCES-BASEL
(2022)
Article
Chemistry, Physical
Xiongsheng Wang, Cuicui Yin, Juan Wang, Kaihong Zheng, Zhengrong Zhang, Zhuo Tian, Yongnan Xiong
Summary: The influence of wetting gradient on the viscous fingering phenomenon was studied using the lattice Boltzmann method. It was found that the gradual increase in wettability of the porous media improves the flow front stability and can suppress viscous fingering. The wetting gradient has a more significant effect on flow front stability under conditions of high viscosity ratio and large porosity.
Article
Mathematics, Applied
Rizwan Ali, Muhammad Imran Asjad, Ali Akgul
Summary: This study investigates the modeling of heat and mass transfer flow of hybrid nanofluid in water and engine oil, utilizing Caputo fractional power law derivative and Laplace transform technique. The results show that variations in fractional parameters alpha, beta, and gamma can control the behavior of the fluid, with water-based hybrid nanofluids having higher temperature and velocity compared to engine oil-based ones. Comparisons with previous results indicate good agreement in limiting cases.
JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS
(2021)
Article
Energy & Fuels
Matheus C. Ribeiro, Jefferson G. Filgueiras, Andre Souza, Pedro M. Vianna, Rodrigo B. V. de Azeredo, Ricardo Leiderman
Summary: This study presents an efficient computational implementation for image-based simulations of NMR diffusion experiment in porous media using random walks. The results indicate that the diffusion experiment has the potential for permeability prediction, with tortuosity and surface-to-volume ratio correlating better with permeability than porosity.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Mechanics
Jie Sun, Liejin Guo, Jiqiang Fu, Jiaqiang Jing, Xiaoyun Yin, Yingda Lu, Amos Ullmann, Neima Brauner
Summary: This paper proposes a new three-zone model for modeling eccentric core-annular flow and demonstrates its accuracy by comparing its predictions with experimental data. The model shows great potential for simulating viscous oil-water eccentric core-annular flows and has broad applicability in industrial settings.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2022)
Article
Mathematics, Applied
Yuli D. Chashechkin, Artem A. Ochirov
Summary: For the first time, the theory of singular perturbations in a unified formulation is used to study the propagation of two-dimensional periodic perturbations, including different types of surface waves and accompanying ligaments, in a viscous continuously stratified fluid. The research findings show that when the wavelength reaches the stratification scale, the liquid behaves homogeneously. As the wave frequency approaches the buoyancy frequency, the energy transfer rate decreases.
Article
Mathematics, Interdisciplinary Applications
Tao Jiang, Yue Li, Peng-Nan Sun, Jin-Lian Ren, Qiang Li, Jin-Yun Yuan
Summary: This work proposes a new viscoelastic two-phase CWCSPH-IT model combined with improved interface treatments for investigating high density ratio two-phase flows. Through simulations of benchmark problems, the model's validity and reliability in handling complex viscous or viscoelastic multi-phase problems have been demonstrated.
COMPUTATIONAL PARTICLE MECHANICS
(2022)
Article
Thermodynamics
Y. Gong, W. P. Jones, A. J. Marquis
Summary: This study numerically investigates premixed turbulent counter-flow flames using Large Eddy Simulation, adopting a transported probability density function approach for sub-grid scale turbulence-chemistry interactions. The results successfully reproduce the velocity field and local extinction processes in the flame region, showing good agreement with measurements. The study highlights the capability of the LES-pdf method in analyzing premixed opposed jet turbulent flames.
FLOW TURBULENCE AND COMBUSTION
(2021)
Article
Optics
Fan Zou, Jing Zuo, Chao Geng, Feng Li, Jiali Jiang, Jiaying Liu, Xin Zhou, Zhihua Fan, Xiaoyu Ma, Xinyang Li
Summary: A new method based on continuous carrier was proposed for beam combining of pulsed fiber lasers with low repetition frequency, which significantly improved the combining efficiency. This research has the potential to be further applied to combine pulsed lasers with lower repetition frequency, paving the way for large-scale coherent beam combining of high-power and high-quality pulsed fiber lasers.
OPTICAL ENGINEERING
(2021)
Article
Thermodynamics
Poorigaly Nanjundaswami Vinaykumar, Thipeswamy Anusha, Ulavathi Shetter Mahabaleshwar, Basma Souayeh
Summary: The effect of mass transpiration parameter on the flow of viscous gas past a porous stretching/shrinking sheet with Navier's slip is explored. The mass transfer characteristics are also examined. The physical flow problem is described using the Navier-Stokes and mass equations, which are transformed into a system of ordinary differential equations via similarity variables. The slip flow model is used to analyze the total mass transfer on the moving sheet.
Article
Automation & Control Systems
Wojciech Gorny, Jose M. Mazon
Summary: This paper investigates least gradient functions in metric random walk spaces, including those on locally finite weighted connected graphs and nonlocal least gradient functions on (N) as special cases. Assuming the satisfaction of a Poincare inequality, the Euler-Lagrange equation associated with the least gradient problem is studied. Additionally, the Poincare inequality is proven in various settings.
ESAIM-CONTROL OPTIMISATION AND CALCULUS OF VARIATIONS
(2021)
Article
Water Resources
Nickolay M. Evstigneev, Oleg I. Ryabkov, Kirill M. Gerke
Summary: This paper presents a high efficiency Stokes solver for incompressible flow in porous media. The solver utilizes a fast algebraic multigrid method on graphics processing units (GPUs) to reduce memory usage and accelerate computation. A simple MAC-type staggered finite difference discretization is used, and a coupled Stokes saddle-point type system is directly solved on a GPU. The method includes topological domain analysis on a GPU to remove isolated volumes with no flow. Various types of boundary conditions and efficient parallel strategies for GPUs are considered. The method is extensively benchmarked against analytical solutions and applied problems from digital rock physics. The results demonstrate the effectiveness and efficiency of the proposed method.
ADVANCES IN WATER RESOURCES
(2023)
Article
Energy & Fuels
Kamila Vavrova, Tomas Kralik, Lukas Janota, Olga Solcova, Milan Carsky, Karel Soukup, Miroslav Vitek
Summary: The treatment and disposal of sewage sludge is a critical problem in wastewater treatment plants, and the European Union produces a significant amount of dry matter of sewage sludge annually. Due to the harmful substances in sewage sludge, regulations on sludge management in EU countries will be tightened. One possible solution is the production of biofuel from sewage sludge enriched with waste celluloses, which has been proven to have comparable quality to conventional fossil fuels. Economic analysis shows that solar dryer technology provides the lowest levelised cost of energy, making the alternative biofuel competitive with lignite.
Article
Polymer Science
Katerina Setnickova, Karel Jerabek, Tomas Strasak, Monika Mullerova, Vera Jandova, Karel Soukup, Roman Petrickovic, Hui-Hsin Tseng, Petr Uchytil
Summary: In recent years, there has been extensive research on porous materials due to their excellent properties and potential use in various areas. Hyper-crosslinked porous polymers (HCLPs) have attracted attention because of their high surface area, porosity, low density, stability, and superior adsorption capabilities. This study focuses on the synthesis, characterization, and gas adsorption performance of a series of novel styrene-based HCLPs, which were prepared through a two-step process involving radical copolymerization and impregnation with polyamines. The impregnation significantly improved the selectivity of CO2/N-2 and CO2/CH4 adsorption.
Article
Chemistry, Physical
Kveta Jiratova, Martin Cada, Iryna Naiko, Alina Ostapenko, Jana Balabanova, Martin Kostejn, Jaroslav Maixner, Timur Babii, Pavel Topka, Karel Soukup, Zdenek Hubicka, Frantisek Kovanda
Summary: Hollow cathode plasma sputtering is a beneficial method for preparing catalysts in the form of thin oxide films on supports, which is especially suitable for catalytic total oxidation of volatile organic compounds (VOCs), offering an economically feasible and environmentally friendly approach to VOC abatement.
Article
Biochemistry & Molecular Biology
Karel Soukup, Pavel Topka, Jaroslav Kupcik, Olga Solcova
Summary: This paper reports the preparation of a thermally stable polybenzimidazole electrospun membrane as a support for a platinum catalyst used in the total oxidation of volatile organic compounds. Compared with commercial pelletized catalysts, the membrane with high porosity provides easy accessibility to the platinum active sites and exhibits a low pressure drop. Catalysts with desired platinum particle sizes were obtained by tuning the preparation conditions. The catalyst containing only 0.08 wt.% of platinum achieved high conversion of all model volatile organic compounds at moderate temperatures, which is important for cost reduction of emission abatement technology.
Article
Soil Science
Dmitriy S. Fomin, Anna Yudina, Konstantin A. Romanenko, Konstantin N. Abrosimov, Marina Karsanina, Kirill M. Gerke
Summary: Through detailed X-ray microtomography imaging study, we revealed the dynamics of soil pore structure under slow water changes for Albic Retisols. By using binary pore-solid segmentations, we were able to visualize structural dynamics and compute major morphological metrics. Contrary to previous findings for compacted soils, our analysis showed that the studied soil degraded after the wetting-drying cycle.
Article
Environmental Sciences
Shan Wang, Catherine Spurin, Tom Bultreys
Summary: Representative elementary volumes (REVs) are important for studying subsurface multiphase flow at the continuum scale. Previous research on fluctuations in multiphase flow was limited to small samples. In this study, we used high-resolution imaging to observe steady-state co-injection experiments on a larger scale, revealing different behaviors at the cm-scale compared to mm-scale samples. Our findings suggest the importance of considering viscous forces and the potential for non-Darcy like upscaled behavior.
WATER RESOURCES RESEARCH
(2023)
Article
Environmental Sciences
Marketa Spacilova, Pavel Dytrych, Martin Lexa, Lenka Wimmerova, Pavel Masin, Robert Kvacek, Olga Solcova
Summary: This study focuses on developing a technology for removing microplastics from wastewater using a sorption process. It can be used in wastewater treatment plants as well as other water sources. Cheap natural materials like zeolites and bentonites were tested as potential sorbents. The study also explores modifying the sorbents to improve efficiency and lifespan. Microplastic removal was successful in both lab-scale and semi-operational sorption units, with an efficiency of over 90%.
Review
Chemistry, Medicinal
Jaianth Vijayakumar, Niloofar Moazami Goudarzi, Guy Eeckhaut, Koen Schrijnemakers, Veerle Cnudde, Matthieu N. Boone
Summary: This article reviews the recent developments in high-resolution X-ray microtomography and its application towards different tablet characterizations, highlighting its indispensability in the pharmaceutical industry.
Article
Chemistry, Analytical
Jose Roberto Tenorio Filho, Jasper Goethals, Reza Aminzadeh, Yawar Abbas, Dulce Elizabeth Valdez Madrid, Veerle Cnudde, Gunter Vermeeren, David Plets, Stijn Matthys
Summary: This paper introduces an innovative automated and wireless system for continuous monitoring of concrete structures. By using embedded electrical resistivity sensors and wireless data transmission, real-time data collection becomes possible. The dielectric properties of concrete and the effects of hardware devices on concrete properties and data transmission were investigated through experiments.
Article
Environmental Sciences
Shan Wang, Arjen Mascini, Leonardo C. Ruspini, Pal-Eric oren, Tom Bultreys
Summary: The wetting properties of pore walls have a strong effect on multiphase flow through porous media. This study investigates the fluid behavior in sandstones with complex pore structures and non-uniform wettability. The experiments reveal slow filling events in mixed-wet samples, which can be attributed to the presence of microporosity and wetting heterogeneity. These events contribute to a significant portion of the sample's total absolute permeability.
WATER RESOURCES RESEARCH
(2023)
Article
Multidisciplinary Sciences
Sebastiaan Godts, Scott Allan Orr, Michael Steiger, Amelie Stahlbuhk, Tim De Kock, Julie Desarnaud, Hilde De Clercq, Veerle Cnudde
Summary: This study analyzed several thousand realistic salt mixtures found in weathered stone using thermodynamic calculations and identified two common mixture types and their behavior. The critical relative humidity points of the most frequently occurring 14 salts were discussed. These findings have implications for understanding salt weathering processes and designing experimental stone weathering research.
SCIENTIFIC REPORTS
(2023)
Article
Geochemistry & Geophysics
Marta Valaskova, Veronika Blahuskova, Miroslava Filip Edelmannova, Lenka Matejova, Karel Soukup, Eva Plevova
Summary: This study focuses on the development of ceramic bricks using fly ash and kaolins or vermiculites as raw materials. The addition of potassium in the mixtures positively affects the firing temperature, porosity, and compressive strength of the bricks. The crystallization of mullite and forsterite in the bricks is influenced by the presence of certain minerals. The ceramic bricks also show potential for photocatalytic hydrogen production.
Article
Physics, Fluids & Plasmas
Aleksei Samarin, Vasily Postnicov, Marina V. Karsanina, Efim V. Lavrukhin, Dina Gafurova, Nikolay M. Evstigneev, Aleksey Khlyupin, Kirill M. Gerke
Summary: Correlation functions (CFs) are structural descriptors and surface-surface (Fss) CFs and surface-void (Fsv) CFs provide additional information about the interface between phases. A method to compute these functions using edge-detecting filters in digital images is proposed. The developed digital approach allows for the analysis and enhancement of porous materials based on experimental images.