Article
Construction & Building Technology
G. Duan, K. Nakamae, T. Takemi
Summary: Using large-eddy simulation, the dispersion of a pollutant scalar is investigated for turbulent boundary-layer flows developed over real urban regions. The study reveals a quantitative connection between ventilation and urban morphometric indices, such as packing densities and building-height variability. However, the relationship between ventilation and other morphometric indices remains unclear.
BUILDING AND ENVIRONMENT
(2023)
Article
Thermodynamics
Naiping Gao, Ruge Wang, Yan Wu, Zhu Wu
Summary: This study used computational fluid dynamics simulations to analyze different tracer gas methods in building ventilation. The results showed that there is deviation in evaluating ventilation effectiveness with different tracer gases, and the error is introduced by non-passive dispersion. The behavior of tracer gas dispersion depends on the release rate and density difference, with smaller release rate and density difference resulting in more passive dispersion. Heavier tracer gas tends to overestimate the performance of upper supply and lower exhaust ventilation, while lighter tracer gas aggravates the overestimation for lower supply and upper exhaust ventilation.
BUILDING SIMULATION
(2023)
Article
Environmental Sciences
Shushuai Mao, Jianlei Lang, Tian Chen, Shuiyuan Cheng
Summary: A novel approach combining parameter sensitivity analysis and optimization methods was proposed to optimize source inversion performance by improving empirical schemes. Results showed significant improvements in predicting air pollutant concentrations and accuracy in source parameters through optimization of dispersion coefficients under different atmospheric conditions. The study provides valuable insights for obtaining accurate source information and enhancing air pollution management and emergency response.
ENVIRONMENTAL POLLUTION
(2021)
Article
Construction & Building Technology
Steven Hanna
Summary: This paper focuses on estimating the risk of a person indoors becoming infected with COVID-19, specifically looking at the near-field transport and dispersion of the virus particles. The study suggests that the transport and dispersion process can be modeled using commonly used analytical formulations such as a slab model, a Gaussian plume model, or a diffusivity model. The proposed slab model is validated using observations from a tracer experiment in airplanes, showing agreement with actual concentration and dose measurements within a factor of two or three.
Article
Environmental Sciences
L. E. Palman, A. E. Trento, A. M. Alvarez
Summary: This study employed field tracer tests and numerical modeling to analyze scalar transport in a section of the Salado River, showing the impact of complex flow patterns and bathymetric irregularities on concentration curves. Both lateral and longitudinal dispersion coefficients played significant roles in particle transport in the river.
WATER AIR AND SOIL POLLUTION
(2021)
Article
Environmental Sciences
Kyong Oh Baek, Dong Yeol Lee
Summary: This study develops a simple and practical formula for estimating transverse dispersion coefficients in meandering natural rivers, which are crucial for predicting solute transport. The formula relies on one dimensionless hydraulic parameter and is validated by comparing it with previously established equations. It is applied to natural river bends in the Nakdong River of Korea, showing promising accuracy. This formula offers a simplified approach to estimating transverse dispersion in meandering rivers when tracer and secondary flow data are unavailable, and can be further refined to capture the complex interplay between topography and transverse dispersion.
Rating: 8/1
Article
Engineering, Civil
Patrick O. West, Stephen G. Wallis, Frederick C. Sonnenwald, James R. Hart, Virginia R. Stovin, Ian Guymer
Summary: This study quantified transverse solute mixing across a vegetation-generated horizontal shear layer using laser-induced fluorometry techniques, and developed a two-dimensional finite difference model to describe transverse concentration profiles in flows with transverse velocity and dispersion variations. Continuous function descriptions produced slightly better modeled solute concentration profiles compared to simplified step inputs when laboratory data were available.
JOURNAL OF HYDRAULIC RESEARCH
(2021)
Article
Environmental Sciences
Erich T. Hester, Katherine Y. Santizo, Abenezer A. Nida, Mark A. Widdowson
Summary: The mixing of surface water and groundwater in shallow sediments is crucial for biogeochemical cycling and contaminant migration. However, understanding of mixing processes in hyporheic zones is limited, with thin transverse mixing zones observed in experiments, influenced by surface water head drop. Transient experiments also showed increased mixing zones, possibly due to temporary addition of dispersion.
JOURNAL OF CONTAMINANT HYDROLOGY
(2021)
Article
Engineering, Civil
Lauren E. E. Schwab, Chris R. R. Rehmann
Summary: An expression for the transverse mixing coefficient in a rectangular channel is derived to evaluate the importance of transverse turbulent diffusion. Both vertical and transverse turbulent diffusion contribute appreciably to transverse shear dispersion, and the direct contribution of transverse turbulent diffusion to transverse mixing is important for a range of conditions commonly observed in natural channels. A comparison of predicted and measured transverse mixing coefficients supports including turbulent diffusion in analyses of transverse mixing - both in its effect on shear dispersion and as a direct mechanism of transport.
JOURNAL OF HYDRAULIC RESEARCH
(2023)
Article
Environmental Sciences
Shang Gao, Mona Kurppa, Chak K. Chan, Keith Ngan
Summary: This study examines the dispersion of cooking-generated aerosols from an urban street canyon using building-resolving computational fluid dynamics. The results show that the inclusion of aerosol dynamic processes decreases the mean canyon-averaged number concentration by 15%-40% for cooking emissions, while the effect is weaker for traffic-generated aerosols. Deposition and coagulation have comparable effects on boiling, but coagulation dominates for deep-frying. Deposition is maximised inside the leeward corner vortices, while coagulation increases away from the source. The qualitative nature of aerosol dynamics within urban canopies is determined by the ratio of the aerosol timescales to the relevant dynamical timescale.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2022)
Article
Engineering, Chemical
M. Echarri-Giacchi, J. M. Martin-Martinez
Summary: Nanosilica dispersion was added to waterborne polyurethane dispersion using different physical mixing procedures, affecting the properties of the resulting polyurethanes. The dispersion of nanosilica particles led to higher thermal stability of the polyurethanes, but decreased the wettability and T-peel strength due to the migration of acrylic moieties. The mechanical properties, specifically the single lap-shear strength, did not significantly change with the addition of nanosilica.
INTERNATIONAL JOURNAL OF ADHESION AND ADHESIVES
(2023)
Article
Geosciences, Multidisciplinary
Wenguang Shi, Quanrong Wang, Hongbin Zhan, Renjie Zhou, Haitao Yan
Summary: In this study, a physically based new model and its associated analytical solutions in the Laplace domain were developed to interpret reactive transport in subsurface systems. The model performed better than previous models in interpreting experimental data. Sensitivity analysis demonstrated that the model is sensitive to mobile porosity and wellbore volume.
HYDROLOGY AND EARTH SYSTEM SCIENCES
(2023)
Article
Multidisciplinary Sciences
Mehdi Asadollahzadeh, Rezvan Torkaman, Meisam Torab-Mostaedi, Mojtaba Saremi
Summary: This study focuses on the recovery of zinc ions through solvent extraction in a pulsed contactor. Numerical computations were conducted to validate the experimental data, and the results showed that the intensification of the process with the pulsed condition achieved higher mass transfer rates. The increase in pulsation intensity and phase flow rates had a positive impact on the performance of the extractor.
SCIENTIFIC REPORTS
(2022)
Article
Water Resources
Chen Wang, Ching-Sheng Huang, Chenchen Tong, Cheng-Haw Lee
Summary: This study develops two new analytical models for radially divergent tracer tests. One model considers skins as an adsorptive Robin boundary condition, while the other model applies skin's governing equation. The analytical solutions of the models are derived, and the deep neural network is utilized for obtaining the solution of the second model. The results suggest the applicability of the boundary condition and provide reliable predictions of parameters by considering the absorbed and non-absorbed tracers.
ADVANCES IN WATER RESOURCES
(2023)
Article
Geosciences, Multidisciplinary
Angelo Aloisio, Ferdinando Totani, Rocco Alaggio, Gianfranco Totani
Summary: The estimation of shear wave velocity (Vs) is essential in seismic engineering, and various methods exist for estimating Vs. The study in Macerata, Italy, shows that Lamb waves may have a significant impact on Vs up to a depth of 100 meters. Surface waves rapidly decrease in amplitude with depth, but their influence may still be crucial at depths often overlooked in standard geotechnical investigations.
Article
Environmental Sciences
Eun Jin Han, Inhwan Park, Young Do Kim, Il Won Seo
ENVIRONMENTAL EARTH SCIENCES
(2016)
Article
Engineering, Civil
Il Won Seo, Hwang Jeong Choi, Young Do Kim, Eun Jin Han
JOURNAL OF HYDRAULIC ENGINEERING
(2016)
Article
Engineering, Civil
Eun Jin Han, Yong Sung Park, Young Do Kim, Jae Hyeon Park
JOURNAL OF HYDRO-ENVIRONMENT RESEARCH
(2016)
Article
Engineering, Civil
Inhwan Park, Il Won Seo, Young Do Kim, Eun Jin Han
JOURNAL OF HYDRAULIC ENGINEERING
(2017)
Article
Engineering, Civil
Inhwan Park, Il Won Seo, Young Do Kim, Eun Jin Han
JOURNAL OF HYDRAULIC ENGINEERING
(2017)
Article
Environmental Sciences
Eun Jin Han, Young Do Kim, Kyong Oh Baek, Il Won Seo
ENVIRONMENTAL EARTH SCIENCES
(2019)
Article
Chemistry, Multidisciplinary
Kyong-Oh Baek, Jeong-Min Lee, Eun-Jin Han, Young-Do Kim
Summary: In this study, a hydraulic analysis technique was used to evaluate the efficiency of a pool-weir type fishway. The analysis results showed that the current location of the fishway was not suitable for attracting target fish, and various flow patterns were observed inside the fishway.
APPLIED SCIENCES-BASEL
(2022)
Article
Green & Sustainable Science & Technology
Heelak Choi, Sang-Ik Suh, Su-Hee Kim, Eun Jin Han, Seo Jin Ki
Summary: This study found that deep learning models outperformed the ARIMA model in univariate surface water quality forecasting, but the presence of other related factors in multivariate datasets impacted prediction accuracy, requiring a refined search for optimal values to achieve the best performance.
