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Articles 931 - 960 of 4617

Full-Text Articles in Civil and Environmental Engineering

Study On Long-Lasting Anticorrosive Primer For Steel Deck Paveme Nt In Marin E Environment, Yan Dongbo, Zhuang Yongyi, Liu Yan, Chen Zhenfu, Ceng Deliang Sep 2023

Study On Long-Lasting Anticorrosive Primer For Steel Deck Paveme Nt In Marin E Environment, Yan Dongbo, Zhuang Yongyi, Liu Yan, Chen Zhenfu, Ceng Deliang

Journal of China & Foreign Highway

In steel deck pavement, after the occurrence of local diseases, steel plates are prone to rapid rust to exacerbate the disease development. To this end, based on the waterproof adhesive system of polymethyl methacrylate resin for steel deck pavement under the marine environment, this paper adopted the organosilicone-modified epoxy resin as the main raw material, which was combined with the cashew phenol-modified phenolic amine and polyamide mixed curing agent. Meanwhile, this paper added a new type of environmentally friendly rust prevention pigment to produce the long-lasting anticorrosive primer for steel deck pavement. The technical requirements of the long-lasting anticorrosive primer …

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Research On Structural Design Of Steel-Uhpc Light Composite Beam Of Large-Span Self-Anchored Suspension Bridge, Zhang Xin, Li Yu, Liu Yong Sep 2023

Research On Structural Design Of Steel-Uhpc Light Composite Beam Of Large-Span Self-Anchored Suspension Bridge, Zhang Xin, Li Yu, Liu Yong

Journal of China & Foreign Highway

To optimize the structural scheme of steel-ultra-high performance concrete (steel-UHPC) light composite stiffening beams for large-span self-anchored suspension bridges, by taking the Qinglongzhou Bridge in Yiyang as the research object, this paper employed finite element simulation and full-scale tests to compare and verify three steel-UHPC composite stiffening beam schemes, and compare the indicators such as static behavior and economic properties. The results show that the UHPC stiffened girder is the best choice for the structural performance and economic characteristics. The results show that the UHPC waferboard, UHPC longitudinal rib plate without web reinforcement, UHPC longitudinal rib plate with long bolts …

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Key Technology Of Demolition And Reconstruction Design Of Wudou Bridge, Li Huaqiang Sep 2023

Key Technology Of Demolition And Reconstruction Design Of Wudou Bridge, Li Huaqiang

Journal of China & Foreign Highway

Bridges constructed between the 1960s and 1970s have been damaged to different degrees during operation due to excessive traffic flow and severe overloading of vehicles, and thus cannot meet the requirements for safe passage of vehicles and navigation. Therefore, they need to be demolished and rebuilt. To safely, economically and efficiently demolish the old bridges and rebuild them in-situ, this paper studied a design concept of integrated construction and demolition. Based on the Wudou Bridge demolition and reconstruction project in Foshan, the combination of theoretical analysis and computational simulation was utilized to conduct a multi-scheme study from the perspectives of …

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Analysis Of Internal Force And Deformation Of Double-Row Steel Sheet Pile Cofferdam In Different Working Conditions, Yang Qin, Fang Zhongqiang, Liu Yi, Tu Qiliang Sep 2023

Analysis Of Internal Force And Deformation Of Double-Row Steel Sheet Pile Cofferdam In Different Working Conditions, Yang Qin, Fang Zhongqiang, Liu Yi, Tu Qiliang

Journal of China & Foreign Highway

To understand the internal force and deformation generation mechanism of the double-row steel sheet pile cofferdam in complex stress conditions and determine the most unfavorable working condition, this paper adopted the finite element method to analyze the displacement, axial force of steel tie bars and bending moments of steel sheet piles in various construction stages at different water levels and under different load types. The study shows that the deformation and internal force of the cofferdam are affected by the water level, fill light weight, vertical construction load, horizontal wave load, and wind load. The most unfavorable conditions for displacement …

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Design Of Prefabricated Deep-Water Combined Steel Sheet Pile Cofferdam, Fu Su, Ceng Jian, Yang Suhai, Wang Chao, Deng Songtao Sep 2023

Design Of Prefabricated Deep-Water Combined Steel Sheet Pile Cofferdam, Fu Su, Ceng Jian, Yang Suhai, Wang Chao, Deng Songtao

Journal of China & Foreign Highway

By taking the pier bearing platform 9# of the non-navigable bridge in the eastern flood-relief area of Shenzhen-Zhongshan Link as the research project, this paper introduced the cofferdam structure of prefabricated combined steel sheet piles using the support-first construction process from the aspects of the cofferdam structural form, cross-section type of steel sheet piles, construction process, and support system, and adopted the finite element method to numerically analyze the whole cofferdam construction process. The combined cross-section of cap-shaped steel sheet piles and H-shaped steel greatly improves the rigidity of steel sheet piles. Additionally, the construction process of the support-first method …

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Performance Analysis Of Steel Bridge Deck Reinforced By Uhpc Based On Fracture Mechanics, Long Yiyu, Chen Shuangqing, Tang Chunyan, Peng Yajun, Zhou Zejian Sep 2023

Performance Analysis Of Steel Bridge Deck Reinforced By Uhpc Based On Fracture Mechanics, Long Yiyu, Chen Shuangqing, Tang Chunyan, Peng Yajun, Zhou Zejian

Journal of China & Foreign Highway

At the deck-rib welding joints of orthotropic steel bridge decks, cracking can easily occur under the vehicle load, and the fatigue risk of steel bridge decks can be effectively reduced by UHPC reinforcement. To investigate the effect of UHPC-reinforced steel bridge decks, this paper carried out finite element analysis based on linear-elastic fracture mechanics. By taking the orthotropic steel bridge deck test as the reference, the fatigue performance at the weld toe was calculated, and the reliability of the finite element model was verified. Stress intensity factor calculation analysis was performed by inserting an initial crack at the weld detail, …

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Stress Analysis And Monitoring Of Composite Cable Hanging Basket During Construction, Zhou Su, Li Xinsheng, Liu Chentao, Shao Mingjie Sep 2023

Stress Analysis And Monitoring Of Composite Cable Hanging Basket During Construction, Zhou Su, Li Xinsheng, Liu Chentao, Shao Mingjie

Journal of China & Foreign Highway

Composite cable hanging baskets are also known as front and rear pivot combined hanging baskets. By taking the construction monitoring of a single-tower and double plane cable-stayed bridge as the research project, this paper demonstrated the rationality, practicability and advancement of the composite cable hanging baskets during construction, and carried out modeling analysis of the whole construction stage. Meanwhile, the batch tension values of the construction sections were determined according to the deformation of the hanging basket during the construction stage, and then the theoretical and measured values of the basket’s deformation and stress during the construction stage were analyzed …

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Study On Influence Of Overcrossing Construction Of Xingquan Railway Lyugu No .2 Tunnel To Existing Chenba Tunnel Of Fuxia Railway, Fan Dequan Sep 2023

Study On Influence Of Overcrossing Construction Of Xingquan Railway Lyugu No .2 Tunnel To Existing Chenba Tunnel Of Fuxia Railway, Fan Dequan

Journal of China & Foreign Highway

To study the influence of tunnel crossing construction on the existing tunnel structures, this paper took the overcrossing construction of the existing Chenba tunnel of Fuxia railway of Xingquan railway Lyugu No. 2 tunnel as the research project. By adopting the numerical simulation method of finite element, it studied the change rules of the displacement field and stress field of the existing tunnels affected by the overcrossing construction of the new tunnels. The results show that the influencing range subject to the effect of Lyugu No. 2 tunnel’s excavation on the existing Chenba tunnel is roughly within the range of …

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Research On Performance Simulation Of Previous Concrete Considering Characteristics Of Void Structures, Zheng Shuai, Dan Jingsong, Han Weiwei, Lv Yigang, He Jie, Pei Fucai Sep 2023

Research On Performance Simulation Of Previous Concrete Considering Characteristics Of Void Structures, Zheng Shuai, Dan Jingsong, Han Weiwei, Lv Yigang, He Jie, Pei Fucai

Journal of China & Foreign Highway

Pervious concrete contains a large number of macroscopic voids. To analyze the influence of the void structures on the mechanical properties of pervious concrete, this paper adopted the random void method to build a simulation model of pervious concrete, and study the effect of the characteristics of the void structures on the force properties. Firstly, two kinds of pervious concrete specimens with two void content levels were made indoor, and then the specimens were cut after curing and molding. Next, image enhancement and threshold segmentation were conducted on the section images of the cut surfaces, and two-dimensional digital images of …

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Study On Frost Resistance And Pore Structure Of Nano-Sio 2 Modified Pavement Concrete Under Fatigue Load, Zhou Xuexiang, Zheng Wenshi, Wu Cong Sep 2023

Study On Frost Resistance And Pore Structure Of Nano-Sio 2 Modified Pavement Concrete Under Fatigue Load, Zhou Xuexiang, Zheng Wenshi, Wu Cong

Journal of China & Foreign Highway

To improve the frost resistance of concrete pavement under fatigue load, this paper simulated the freeze-thaw damage of concrete pavement under vehicle load by indoor fatigue loading and alternating freeze-thaw cycling test. Meanwhile, it designed the bending tensile test to test the residual bending tensile strength of nano SiO2-modified pavement concrete after freezing and thawing, and adopted the mercury injection method to test the microscopic pore structures of concrete. Additionally, by employing the electron microscope, the change rules of pores in the concrete under the action of fatigue load were observed, and the effect of nano SiO2 dosage, the number …

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Influence Of Natural Environment On The Serviceability Of Emulsified Asphalt Cold Recycled Mixture, Yang Puxin Sep 2023

Influence Of Natural Environment On The Serviceability Of Emulsified Asphalt Cold Recycled Mixture, Yang Puxin

Journal of China & Foreign Highway

To improve the early serviceability of emulsified asphalt cold recycled mixtures, this paper studied the effect of curing conditions on the mechanical strength and stability of emulsified asphalt cold recycled mixtures by conducting indoor tests. The results show that in the same test conditions, the indoor emulsified asphalt cold recycled mixture can better characterize the serviceability of practical projects. Compared to the indoor specimen mixture, the stability and cleavage strength of field mixture core samples are increased by an average of 5.5% and 10.7% respectively. Under the curing time of no less than 7 d, the stability, cleavage strength and …

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Experimental Study On Recycled Brick Powder Foam Concrete Based On Slurry Substitution Method, Liao Shixian, Huang Lei Sep 2023

Experimental Study On Recycled Brick Powder Foam Concrete Based On Slurry Substitution Method, Liao Shixian, Huang Lei

Journal of China & Foreign Highway

Foam concrete is a kind of porous lightweight building material characterized by sound insulation and noise reduction, heat insulation and fire resistance, heat preservation and frost resistance. However, it has defects such as low strength, high porosity and poor integrity, thus limiting its wide application in the field of building materials. Recycled brick powder can be prepared from construction waste of clay bricks and has certain volcanic ash activity. Meanwhile, the mechanical properties of foam concrete can be improved by employing waste bricks as an admixture in cement-based composite materials. In view of the problems of the cement substitution method, …

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Study On Mix Design And Performance Of Permeable Concrete Considering Sand Ratio And Aggregate To Binder Ratio, Wei Yazhou, Ji Rongqing Sep 2023

Study On Mix Design And Performance Of Permeable Concrete Considering Sand Ratio And Aggregate To Binder Ratio, Wei Yazhou, Ji Rongqing

Journal of China & Foreign Highway

Considering the effect of the sand ratio and aggregate to binder ratio, this paper improved the traditional mix ratio design method-volumetric method, and investigated the influence of the sand ratio, aggregate to binder ratio, and maintenance method on the mechanical properties and permeability coefficient of pervious concrete based on the improved method. The results show that under the sand ratio of 15%, the compressive strength of concrete is significantly increased and the permeability is not affected. When the aggregate to binder ratio is 3.0‒3.1, the compressive strength and permeability coefficient of the concrete can be both considered. Additionally, compared to …

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Experimental Study On Mechanical Properties Of Steel-Polypropylene Mixed Fiber Rubber Concrete, Qiu Jiandong Sep 2023

Experimental Study On Mechanical Properties Of Steel-Polypropylene Mixed Fiber Rubber Concrete, Qiu Jiandong

Journal of China & Foreign Highway

Waste rubber materials can be recycled to obtain rubber aggregates, which can be employed in cement concrete products. This paper carried out mechanical performance tests on ordinary concrete and rubber concrete (rubber substitution rate of 20%) with different fiber combinations (doped MS, co-doped PP, and mixed MS-PP), and mainly examined the slump, density, compressive strength, modulus of elasticity, split tensile strength, and rupture strength of the concrete. The results show that the relevant performance indexes decrease significantly after 20% of rubber aggregate is added to the concrete. However, the mechanical performance of ordinary concrete and rubber concrete with the combination …

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Application Of Bim Forward Design In Complex Three-Dimensional Traffic Design Stage, Wang Bo, Zhu Xinghu, Pei Wangjian, Ge Puta Sep 2023

Application Of Bim Forward Design In Complex Three-Dimensional Traffic Design Stage, Wang Bo, Zhu Xinghu, Pei Wangjian, Ge Puta

Journal of China & Foreign Highway

To improve the accuracy and efficiency of complex three-dimensional traffic design, and provide basic digital data for the whole life cycle, this paper researched and investigated the application of BIM technology in the complex three-dimensional traffic design stage by taking the convergence project of the Qianhai section of Shenzhen Coastal Expressway and Nanping Expressway in Guangdong as a case study. Meanwhile, it put forward the BIM forward design schemes for the fields of roads, bridges, and tunnels, carried out secondary development, and built the three-dimensional parametric model, with the design results optimized. Additionally, design analysis and application were conducted to …

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Research On Interchange Reconstruction Design Of Minxiao Hub, Hu Tian, Tan Ximing, Yi Xuebin, Wei Hui Sep 2023

Research On Interchange Reconstruction Design Of Minxiao Hub, Hu Tian, Tan Ximing, Yi Xuebin, Wei Hui

Journal of China & Foreign Highway

Based on the design of the Minxiao hub interchange, this paper analyzed the technical problems of frequent traffic accidents after the initial reconstruction of Minxiao hub interchange, and put forward corresponding reconstruction suggestions. In the interchange design details, the design points about the dual lanes adopting single lanes and speed change lanes only put forward the distance requirement of 60 m for the transition sections, but whether the gradual changes of the travel lanes and hard shoulders are completed in the same road section or not is not clarified. The initial reconstruction of Minxiao hub interchange is designed to complete …

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Exploring Long-Term Protective Effect Of High Vertical Sand Barrier On Top Of Complex Longitudinal Sand Ridge In Taklamakan Desert, Jin Changning Sep 2023

Exploring Long-Term Protective Effect Of High Vertical Sand Barrier On Top Of Complex Longitudinal Sand Ridge In Taklamakan Desert, Jin Changning

Journal of China & Foreign Highway

By taking the high vertical sand barriers deployed on the top of the complex longitudinal sand ridges in the hinterland of Taklamakan Desert as the object, this paper investigated the sand protection effect from the long-term perspective on the basis of several years’ comparative observation. The result analysis shows that in addition to the recognized sand blocking effect, high vertical sand barriers also have a more important role of sand fixation, which means that the barriers can change the original overall movement of sand dunes into only the falling sand slope forward, with the windward slopes basically fixed. Even if …

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Study And Implementation Of Jacking Scheme Of Vertical Curve Beam With Two -Way Longitudinal Slope Without Adjusting Temporary Pier Top Elevation, Zhang Hongwu, Ke Hongjun, Chen Zhuoyi, Yang Wu Sep 2023

Study And Implementation Of Jacking Scheme Of Vertical Curve Beam With Two -Way Longitudinal Slope Without Adjusting Temporary Pier Top Elevation, Zhang Hongwu, Ke Hongjun, Chen Zhuoyi, Yang Wu

Journal of China & Foreign Highway

The bridge alignment design is the straight line+circular curve+straight two-way longitudinal slope vertical curve variable curvature steel bridge jacking. To deal with this problem, this paper analyzed the shortcomings of existing schemes such as real-time or multiple adjustments to the temporary pier top elevation, and proposed a jacking scheme of taking full advantage of the steel bridge’s characteristics including small flexural rigidity, strong adaptive deformation ability and high material strength, without adjusting the temporary pier top elevation. Additionally, the whole-process finite element simulation analysis was conducted on this scheme via a background project, with the calculation results revealing safety and …

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Data Analysis And Early Warning Platform For Bridge Health Monitoring Based On Matlab-Java Fusion, Wang Zhiwen, Mao Yongjia, Ding Youliang Sep 2023

Data Analysis And Early Warning Platform For Bridge Health Monitoring Based On Matlab-Java Fusion, Wang Zhiwen, Mao Yongjia, Ding Youliang

Journal of China & Foreign Highway

Bridge health monitoring provides important support for daily operation and maintenance management of bridges. Meanwhile, real-time analysis, evaluation and early warning of bridge health monitoring data are the core requirements for enhancing bridge monitoring and safety protection, which can help grasp the operation status of bridge structures in real time and guard against major safety risks of bridge operation. This paper combined traditional signal processing and statistical analysis with modern machine learning and deep learning, and developed a platform for real-time analysis and warning of bridge health monitoring data based on Matlab-JAVA integration. Online cleaning, feature extraction, performance evaluation and …

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Application Of Dry Sbs Modification Technology In Yanhai Highway, Zhang Han, Meng Chunlin, Zhao Mingfang, Lu Chuanzhong, Ji Guoqi Sep 2023

Application Of Dry Sbs Modification Technology In Yanhai Highway, Zhang Han, Meng Chunlin, Zhao Mingfang, Lu Chuanzhong, Ji Guoqi

Journal of China & Foreign Highway

Dry SBS-modified asphalt pavement technology is to produce SBS-modified asphalt mixtures by adding specific SBS modifiers, which aims to solve the performance degradation of SBS-modified asphalt in transportation and storage. By relying on the coastal highway repair projects, this paper compared the effects of different dry SBS mixing contents on the test results by the indoor dry SBS and matrix asphalt compatibility test and asphalt mixture performance evaluation test. Meanwhile, based on the test results, the recommended dry SBS mixing content for the coastal highway upper layer milling and resurfacing maintenance project was proposed and applied on a large scale …

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Hydrothermal Carbonization Of Biomass Wastes: Sustainability And Geochemistry, Michael A. Kruge, Teresa A. Centeno, Alvaro Amado-Fierro, José Manuel González-Lafuente, Ruben Forjan-Castro, José Luis Gallego Sep 2023

Hydrothermal Carbonization Of Biomass Wastes: Sustainability And Geochemistry, Michael A. Kruge, Teresa A. Centeno, Alvaro Amado-Fierro, José Manuel González-Lafuente, Ruben Forjan-Castro, José Luis Gallego

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Introduction. To reduce the stream of solid waste going to landfills, innovative means for beneficial use are essential. The diversity and volume of organic wastes pose singular problems and opportunities for recovery and circularity. Common processes for organics include conversion to biofuels and carbonization to biochar, typically done by torrefaction (dry pyrolysis). Research on biochar explores its potential as pollutant adsorbent, agricultural or polluted soil amendment, biofuel (directly or as feedstock), and for carbon sequestration (Ighalo et al., 2022; Cavali et al., 2023). Recently, other processes at lower temperatures such as hydrothermal carbonization (HTC) offer new possibilities (Seshadri et al., …

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Water-Energy-Food Linkages In Community Smallholder Irrigation Schemes: Center Pivot Irrigation In Rwanda, Ankit Chandra, Derek M. Heeren, Lameck O. Odhiambo, N. Brozovic Sep 2023

Water-Energy-Food Linkages In Community Smallholder Irrigation Schemes: Center Pivot Irrigation In Rwanda, Ankit Chandra, Derek M. Heeren, Lameck O. Odhiambo, N. Brozovic

Daugherty Water for Food Global Institute: Faculty Publications

Water, energy, and food are linked in intricate ways in irrigated agriculture and understanding the interplay of these components is crucial for sustainable and profitable crop production, particularly in smallholder setting such as in sub-Saharan Africa. This study evaluates water-energy-food linkages, engineering and economic performance, irrigation decision making, and challenges faced around water management in a community-based mechanized irrigation scheme in Rwanda. The research is the first to analyze such as scheme, which uses technology typically used by large farmers in a smallholder setting. The study investigates the variation in water requirements and the relationship and impacts of this variability …

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Reaction Steps In Heterogeneous Photocatalytic Oxidation Of Toluene In Gas Phase—A Review, Yerzhigit Tulebekov, Zhandos Orazov, Bagdat Satybaldiyev, Daniel D. Snow, Raphaël Schneider, Bolat Uralbekov Sep 2023

Reaction Steps In Heterogeneous Photocatalytic Oxidation Of Toluene In Gas Phase—A Review, Yerzhigit Tulebekov, Zhandos Orazov, Bagdat Satybaldiyev, Daniel D. Snow, Raphaël Schneider, Bolat Uralbekov

Nebraska Water Center: Faculty Publications

A review of the current literature shows there is no clear consensus regarding the reaction mechanisms of air-borne aromatic compounds such as toluene by photocatalytic oxidation. Potential oxidation reactions over TiO2 or TiO2-based catalysts under ultraviolet and visible (UV/VIS) illumination are most commonly considered for removal of these pollutants. Along the pathways from a model pollutant, toluene, to final mineralization products (CO2 and H2O), the formation of several intermediates via specific reactions include parallel oxidation reactions and formation of less-reactive intermediates on the TiO2 surface. The latter may occupy active adsorption sites and …

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Reconstructing 42 Years (1979–2020) Of Great Lakes Surface Temperature Through A Deep Learning Approach, Miraj Kayastha, Tao Liu, Daniel Titze, Timothy C. Havens, Chenfu Huang, Pengfei Xue Aug 2023

Reconstructing 42 Years (1979–2020) Of Great Lakes Surface Temperature Through A Deep Learning Approach, Miraj Kayastha, Tao Liu, Daniel Titze, Timothy C. Havens, Chenfu Huang, Pengfei Xue

Michigan Tech Publications

Accurate estimates for the lake surface temperature (LST) of the Great Lakes are critical to understanding the regional climate. Dedicated lake models of various complexity have been used to simulate LST but they suffer from noticeable biases and can be computationally expensive. Additionally, the available historical LST datasets are limited by either short temporal coverage (<30 >years) or lower spatial resolution (0.25° × 0.25°). Therefore, in this study, we employed a deep learning model based on Long Short-Term Memory (LSTM) neural networks to produce a daily LST dataset for the Great Lakes that spans an unparalleled 42 years (1979–2020) at …

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Design Of Stormwater Bmps For Surface And Groundwater Protection Based On Site-Scale Soil Properties: Phase I, Kelly Kibler, Lisa Chambers, Melanie Beazley Aug 2023

Design Of Stormwater Bmps For Surface And Groundwater Protection Based On Site-Scale Soil Properties: Phase I, Kelly Kibler, Lisa Chambers, Melanie Beazley

Florida DOT

Much of Earth’s nutrient cycling takes place in soils. Characteristics of soils control physical, chemical, and biological processes that determine rates of nutrient fluxes, storage, or transformation. As remediation of excess nutrients in stormwater runoff is one function of stormwater Best Management Practices (BMPs), the soil profile constitutes one of the most important factors of BMP design. Variation observed in BMP effectiveness (e.g., why one BMP design works effectively in one place and not another) can often be explained by variations in the soil profile, either through direct means or by a soil’s influence on hydraulics of stormwater flow through …

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Verification Of Astm Centrifugation Equations For Soil Suction Determination, Esteban Maclein Miranda Pinzon Aug 2023

Verification Of Astm Centrifugation Equations For Soil Suction Determination, Esteban Maclein Miranda Pinzon

Graduate Theses and Dissertations

The unit correction constant (B) in the ASTM D6836 standard needs to be evaluated. The B-value was proposed to be 0.00548 instead of 0.00553. This apparent discrepancy led to an investigation comparing the predicted and measured suction values for high air entry (HAE) ceramic disks. A Beckman-Coulter Model J6-MI six-bay centrifuge and a WP4C Dewpoint Potentiameter were used in the testing program. HAE ceramic disks rated with bubbling pressures of 3-bar and 5-bar were used as analogue soil specimens. The HAE ceramic disks were spun in the small-scale centrifuge to apply prescribed suction amounts and then placed in the WP4C …

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Healthcare Built Environment And The Covid-19 Pandemic, A Mixed-Method Study, Mohammad Saleh Nikooopayan Tak Aug 2023

Healthcare Built Environment And The Covid-19 Pandemic, A Mixed-Method Study, Mohammad Saleh Nikooopayan Tak

All Theses

The outbreak of COVID-19 presented an unparalleled risk to public health, leading to urgent scientific efforts in understanding transmission mechanisms and mitigating risks, especially in healthcare settings. This mixed-methods study examines knowledge advancement regarding indoor air quality in healthcare facilities during the pandemic. A systematic literature review of 163 post-COVID studies identifies key research thrusts and 31 recommendations related to building ventilation, air filtration, surface disinfection, and monitoring. Comparison with over 200 pre-pandemic publications reveals both reliance on established infection control principles and unique contributions, such as detecting viral RNA in air and surface samples indicating potential airborne and fomite …

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Combining Semi-Continuous And Discrete Water Quality Data To Characterize Solute Transport, Biogeochemical Processes, And Wildfire Disturbances In Fluvial Systems, Justin Rae Nichols Aug 2023

Combining Semi-Continuous And Discrete Water Quality Data To Characterize Solute Transport, Biogeochemical Processes, And Wildfire Disturbances In Fluvial Systems, Justin Rae Nichols

Civil Engineering ETDs

In the past decade, high-frequency water quality sondes have become more abundant in watersheds across North America and Europe and are gaining a foothold in Asia and South America. In this dissertation, three relevant topics associated with high-frequency data are investigated, i.e., the impact of winter’s precipitation on surface water quality and stream metabolism, the longitudinal propagation of wildfire disturbances through a fluvial network, and the use of machine learning with high-frequency data to estimate fluvial nutrient processing. First, we found that significant snow precipitation can cause surface water anoxia and declines in stream metabolism. Second, our data illustrate that …

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Evaluating The Feasibility Of Using Strain Measured During Sinusoidal Rate Pumping Tests To Characterize An Aquifer, Riley Blais Aug 2023

Evaluating The Feasibility Of Using Strain Measured During Sinusoidal Rate Pumping Tests To Characterize An Aquifer, Riley Blais

All Theses

Pumping tests with sinusoidal variation in pumping rate have been proposed as a method for improving aquifer characterization. These tests can interrogate a larger aquifer volume than slug tests and they can be more sensitive to small variations in drawdown. Current methods of using sinusoidal variations of rate are based on measuring pressure signals from the reservoir or aquifer, which requires access to monitoring wells. An alternative approach has been developed that measures the strain in the vadose zone instead of pressure in the reservoir. An instrument has been developed at Clemson University that can measure small strains using optical …

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Phase Distribution Of Nickel, Chromium, And Cobalt In Seawater At Olivine-Enriched Beaches: Implications For Carbon Capture By Enhanced Silicate Weathering, Nathaniel J. Padrnos Aug 2023

Phase Distribution Of Nickel, Chromium, And Cobalt In Seawater At Olivine-Enriched Beaches: Implications For Carbon Capture By Enhanced Silicate Weathering, Nathaniel J. Padrnos

Master's Theses

The application of olivine to coastal areas is a proposed method of removing carbon dioxide from the atmosphere for climate change mitigation. Olivine is abundant and dissolves relatively fast, but it contains trace amounts of nickel (Ni), chromium (Cr), and cobalt (Co) which may be toxic to marine biota in cases of widespread coastal olivine spreading. Prior studies have suggested that Ni concentrations in marine sediments and/or the overlying water column due to olivine dissolution could be a limiting factor for its carbon capture potential. Therefore, it is critical to understand and model the processes affecting trace metal bioavailability after …

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