Article
Nuclear Science & Technology
M. Lahdour, T. El Bardouni, O. El Hajjaji, E. Chakir, M. Mohammed, Jamal Al Zain, H. Ziani
Summary: NTP-ERSN is a package developed for solving the multigroup form of the Boltzmann transport equation in one-dimensional cartesian geometry by combining pin cells. The accuracy and efficiency of the package are verified using the C5G7 MOX benchmark, showing good agreement with OpenMC calculation code.
NUCLEAR ENGINEERING AND TECHNOLOGY
(2021)
Article
Environmental Sciences
Massimo Rolle, Marina Albrecht, Riccardo Sprocati
Summary: The study focuses on electromigration and provides experimental evidence on the impact of compound-specific properties on macroscopic electrokinetic transport. The experimental outcomes demonstrate that both compound-specific diffusivity and ion charge affect the transport of selected color tracer plumes.
JOURNAL OF CONTAMINANT HYDROLOGY
(2022)
Article
Chemistry, Physical
Frederik H. van Veen, Luca Ornago, Herre S. J. van der Zant, Maria El Abbassi
Summary: This study investigates the variation in conductance values of alkanes using the mechanically controlled break junction technique. By analyzing the time evolution and distance dependence of the measured traces, the single-molecule conductance values for fully stretched molecular configurations are determined. The results provide crucial information for determining the molecular junction configuration.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Energy & Fuels
Kaitlyn Elizabeth Barr, Sooyoung Choi, Junsu Kang, Brendan Kochunas
Summary: This study conducted benchmark calculations for the APR1400 nuclear reactor using the deterministic whole-core simulator MPACT and compared the results with the reference solutions from the Monte Carlo code McCARD. The findings show that MPACT effectively predicts reactivity and power distributions with good agreement to McCARD, despite minor deviations under specific conditions. This research provides insights for improving the accuracy of whole-core transport code libraries.
Article
Engineering, Aerospace
Mohagna J. Pandya, Dennis C. Jespersen, Boris Diskin, James L. Thomas, Neal T. Frink
Summary: The paper describes enhancements made to the unstructured-grid mixed-element cell-centered finite-volume flow solver USM3D for massively parallel computations. The new parallel implementation is verified through comparisons on a given grid, and the accuracy is validated through grid convergence studies and comparison with reference solutions for two benchmark turbulent flows. Scalability assessments are conducted using two different nonlinear iteration methods.
Article
Materials Science, Multidisciplinary
Adrien Socie, Nicolas Seigneur, Benoit Bary, Stephane Poyet, Gaetan Touze
Summary: Coupled Thermal-Hydraulic-Mechanical-Chemical (THMC) approaches are important for assessing the long-term durability of cementitious materials. The authors present a multiphysics approach that overcomes past limitations of THMC modelling and validate it based on accelerated carbonation tests. The approach successfully represents crack patterns and non-uniform degradation depths observed on microtomographic images of carbonated cement samples.
NPJ MATERIALS DEGRADATION
(2023)
Article
Geosciences, Multidisciplinary
Lucas Schauer, Michael J. Schmidt, Nicholas B. Engdahl, Stephen D. Pankavich, David A. Benson, Diogo Bolster
Summary: This article presents a parallelized domain decomposition strategy for mass-transfer particle tracking methods. Different tiling techniques for two and three dimensions are investigated and an optimal tiling is determined based on problem parameters and the number of CPU cores. The efficiency of the parallelized algorithms is demonstrated with simulations of a pure diffusion problem.
GEOSCIENTIFIC MODEL DEVELOPMENT
(2023)
Article
Engineering, Environmental
Julian Sorwat, Adrian Mellage, Markus Maisch, Andreas Kappler, Olaf A. Cirpka, James M. Byrne
Summary: Magnetite nanoparticles are effective in removing and irreversibly sequestering Cr(VI). Experimental and modeling analyses showed that magnetite-coated sand is a promising medium for treating Cr(VI)-contaminated water.
JOURNAL OF HAZARDOUS MATERIALS
(2021)
Article
Environmental Sciences
Bum-Jun Kim, Myoung-Soo Ko
Summary: This study used 2D RTMs and MODFLOW-2005 to identify the origins and pathways of arsenic in soil and water systems and evaluate their contributions. The results showed that mine Y was the primary origin of arsenic, which entered the reservoir through groundwater.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Environmental Sciences
Heng Dai, Fangqiang Zhang, Ming Ye, Alberto Guadagnini, Qi Liu, Bill Hu, Songhu Yuan
Summary: This article introduces a new quasi-Monte Carlo method that can consider both parameter and model uncertainty in handling multi-model process sensitivity indices. Compared to brute force Monte Carlo method and binning method, the quasi-Monte Carlo method performs better in terms of computational cost and theoretical aspects, and has a rigorous theoretical foundation.
WATER RESOURCES RESEARCH
(2022)
Article
Physics, Fluids & Plasmas
G. M. Staebler, E. A. Belli, J. Candy, J. E. Kinsey, H. Dudding, B. Patel
Summary: This paper verifies and calibrates a new quasi-linear transport model based on a large database of gyrokinetic turbulence simulations. The modification of a key parameter in the model is found to be necessary for better fitting temperature and density gradients. The new model shows significantly improved fit in electron and ion energy fluxes compared to previous saturation models, leading to revisions in related models.
Article
Astronomy & Astrophysics
Jin Hu, Shuzhe Shi
Summary: In this study, the multicomponent second-order dissipative relativistic hydrodynamic equations are derived using the moment-expansion method. By computing the transport coefficients using hard-sphere interactions, the role of multiple components and reactive collisions is investigated. It is found that both factors increase the effective cross section, leading to a decrease in transport coefficients and relaxation times. Furthermore, the transport properties are computed using leading-order perturbative QCD cross sections. For both types of cross sections, it is observed that the ratio between the vector current relaxation time and conductivity for a multicomponent fluid is notably different from that for a single-component fluid. Therefore, this study provides a more applicable guideline for such a ratio in phenomenological hydrodynamics simulations.
Article
Computer Science, Interdisciplinary Applications
Yiwei Cheng, Bhavna Arora, S. Sevinc Sengor, Jennifer L. Druhan, Christoph Wanner, Boris M. van Breukelen, Carl Steefel
Summary: Microbially mediated sulfate reduction involves isotopic fractionation, with lighter sulfate isotopologues favored by sulfate-reducing bacteria. Isotopic shifts are used as a proxy for sulfate reduction onset in subsurface systems. A benchmark problem set has been developed for simulating kinetic sulfur isotope fractionation, exploring different mathematical formulations in RTMs. The simulation results from participating RTMs show reasonable agreement across all problem levels.
COMPUTATIONAL GEOSCIENCES
(2021)
Article
Ecology
Swamini Khurana, Falk Hesse, Anke Hildebrandt, Martin Thullner
Summary: The subsurface is a vital component of the Earth's critical zone, where biogeochemical transformations are crucial for nutrient cycling. Spatial heterogeneity influences groundwater microbial biomass distribution and nutrient cycling, neglecting its effects can lead to overestimation of nutrient removal.
Article
Water Resources
Aaron Peche, Thomas Graf
Summary: The study focused on the pipe leakage problem, establishing a numerical benchmark model to accurately calculate the distribution of water levels in the soil affected by leaky pipes. By comparing analytical solutions with numerical models, the accuracy of the models was demonstrated.
URBAN WATER JOURNAL
(2021)
Article
Environmental Sciences
N. A. Fleming, T. A. Morais, K. U. Mayer, M. C. Ryan
Summary: The failure of well integrity can lead to the migration of natural gas, resulting in atmospheric greenhouse gas emissions and impacts on groundwater quality. This study found that gas emissions were mainly concentrated around the wellhead, influenced by various meteorological factors, while gas migration near the wellhead was primarily advective displacement.
ATMOSPHERIC POLLUTION RESEARCH
(2021)
Article
Geochemistry & Geophysics
Xueying Yi, Danyang Su, Bruno Bussiere, K. Mayer
Summary: Thermal cover systems can be used to reduce contaminant mass loadings in waste rock piles located in continuous permafrost regions. A reactive transport modeling study in Northern Canada showed that an appropriate cover design can effectively minimize mass loadings in drainage.
Article
Environmental Sciences
D. Pedretti, B. Vriens, E. K. Skierszkan, P. Bajak, K. U. Mayer, R. D. Beckie
Summary: This study evaluated the ability of dual-domain multicomponent reactive transport models to reproduce breakthrough curves of conservative and reactive solutes observed at an experimental waste-rock pile, leading to the conclusion that the model matches field observations well.
JOURNAL OF CONTAMINANT HYDROLOGY
(2022)
Article
Soil Science
Hannah S. S. Gatz-Miller, Frederic Gerard, Eric P. P. Verrecchia, Danyang Su, K. Ulrich Mayer
Summary: The study investigates the geochemical pathway and carbon sequestration capacity of the Iroko tree's oxalate carbonate pathway (OCP) using a 1D reactive transport model and sensitivity analysis. The results indicate that the precipitation of calcite is limited by the availability of Ca sources and the tree's rate of water and solute uptake.
Article
Environmental Sciences
Cole J. C. Van de Ven, Laura Laurenzi, Ashley C. Arnold, Steven J. Hallam, K. Ulrich Mayer
Summary: With the increasing global use of methanol, the unintentional release and spills of methanol into soils and aquifers pose potential hazards. This study investigates the formation of harmful by-products during methanol biodegradation in natural sand and silt sediments using microcosms.
JOURNAL OF CONTAMINANT HYDROLOGY
(2022)
Article
Environmental Sciences
Elena Petrova, Evgenii Kortunov, K. Ulrich Mayer, Peter Grathwohl, Michael Finkel
Summary: This study investigates denitrification in a ferric iron-containing fractured micritic limestone aquifer in south-west Germany through numerical simulations. The simulations confirm that denitrification primarily occurs in the fractures, with pyrite and siderite providing enough reduction potential to decrease nitrate concentrations. The study also highlights the influence of aquifer properties and the shape of travel time distributions on the uncertainty of modeled concentrations.
JOURNAL OF CONTAMINANT HYDROLOGY
(2022)
Article
Geochemistry & Geophysics
Mingliang Xie, Danyang Su, K. Ulrich Mayer, Kerry T. B. MacQuarrie
Summary: The Canadian concept for a deep geological repository for used nuclear fuel uses compacted bentonite and low-alkali concrete as engineered barrier materials. Chemical alterations are expected at the interfaces between these materials due to their different initial mineralogy and pore water compositions. Simulations show that mineral dissolution and precipitation can occur at the material interfaces, leading to porosity reduction or pore clogging.
APPLIED GEOCHEMISTRY
(2022)
Article
Geosciences, Multidisciplinary
Olenka N. Forde, Aaron G. Cahill, Bernhard Mayer, Roger D. Beckie, K. Ulrich Mayer
Summary: Fugitive gas migration (GM) from compromised oil and gas wells is a global concern. This study investigated the transport and fate of fugitive gas in the vadose zone through simulations and monitoring. The results showed that methane oxidation partially attenuated the natural gas, but variations in grain-size distribution and barometric pressure strongly influenced gas transport and fate, leading to episodic effluxes and lateral gas transport.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Soil Science
Mengqi Jia, Oliver Blume, Richard T. Amos, Danyang Su, David R. Lapen, K. Ulrich Mayer
Summary: Agricultural drainage ditches play a crucial role in regulating moisture levels in fields for crop production and also provide important ecosystem services. This study used a uniform reactive transport model to examine the dynamics of greenhouse gas cycling and biogeochemical processes in crop fields and riparian soils adjacent to a drainage ditch. The simulation results revealed the significant impact of environmental factors, such as soil moisture content, temperature, and nutrient supply, on greenhouse gas emissions. Additionally, the study found no significant difference in greenhouse gas emissions between monitoring locations on the ditch slopes.
Article
Environmental Sciences
Danyang Su, Mingliang Xie, K. Ulrich Mayer, Kerry T. B. MacQuarrie
Summary: The effect of ice sheet geometry on groundwater flow patterns and meltwater ingress was investigated. The results showed that meltwater ingress is much greater in 3D domains with a relatively narrow ice sheet. The penetration depth of meltwater was found to be deeper in high permeability units compared to low permeability units. Additionally, the ingress of dissolved oxygen was most substantial below a narrow ice lobe.
WATER RESOURCES RESEARCH
(2022)
Article
Water Resources
Kartik Jain, Cole J. C. Van De Ven, Kevin G. Mumford, K. Ulrich Mayer
Summary: Gas migration (GM) during energy development and geological carbon storage can lead to emissions, safety concerns, and groundwater quality reduction. Modeling gas release and transport processes is crucial for detecting and monitoring GM and evaluating its environmental impacts.
ADVANCES IN WATER RESOURCES
(2023)
Article
Environmental Sciences
Nicolas Seigneur, Adrien Socie, K. Ulrich Mayer
Summary: Reactive transport modeling is widely used to understand hydrogeochemical processes. The scope of applications has increased towards higher complexity and process coupling. Traditional methods have limitations in decoupling groundwater flow and reactive transport processes. A global implicit compositional approach is presented to integrate flow processes into the reactive transport framework, solving the limitations of traditional methods. The model allows tackling complex problems while accounting for various reactions involving water, gases, and solids.
WATER RESOURCES RESEARCH
(2023)
Article
Environmental Sciences
Sarah Bereswill, Hannah Gatz-Miller, Danyang Su, Christian Toetzke, Nikolay Kardjilov, Sascha E. Oswald, Klaus Ulrich Mayer
Summary: Oxygen availability in soils plays a crucial role in plant growth and productivity. This study used non-invasive imaging techniques to measure the root system architecture, soil moisture, and oxygen concentrations in the root zone of maize. A reactive transport model was constructed based on the experimental data, and different modeling scenarios were compared to match the observed patterns. The results showed that considering the heterogeneity of soil structure and hydraulic parameters improved the accuracy of the model in reproducing soil moisture and oxygen patterns.
VADOSE ZONE JOURNAL
(2023)
Article
Water Resources
Xueying Yi, Danyang Su, Nicolas Seigneur, Klaus Ulrich Mayer
Summary: The oxidation of sulfide minerals in waste rock can lead to elevated sulfate levels, enhanced metal loadings, and low pH conditions. The research indicates that warming climate conditions can affect sulfide mineral weathering rates, impacting the development of permafrost and release of acidic drainage in waste rock piles. Evaluation of thermal covers suggests significant reductions in mass loadings for piles with low and reference reactivity.
FRONTIERS IN WATER
(2021)
Article
Water Resources
Katherine E. Raymond, Nicolas Seigneur, Danyang Su, K. Ulrich Mayer
Summary: Placement methods and material availability during waste rock pile construction can create significant heterogeneities in physical and geochemical parameters, influencing internal pile structure. Numerical modeling shows that the implications of heterogeneity and construction method on acid rock drainage release are scale-dependent, decreasing peak mass loading rates but prolonging ARD release.
FRONTIERS IN WATER
(2021)
