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Articles 3511 - 3540 of 6127

Full-Text Articles in Civil and Environmental Engineering

Towards Effective Design Treatment For Right Turns At Intersections With Bicycle Traffic, David Hurwitz, Mafruhatul Jannat, Jennifer Warner, Christopher M. Monsere, Ali Razmpa Nov 2015

Towards Effective Design Treatment For Right Turns At Intersections With Bicycle Traffic, David Hurwitz, Mafruhatul Jannat, Jennifer Warner, Christopher M. Monsere, Ali Razmpa

Civil and Environmental Engineering Faculty Publications and Presentations

The overall goal of this research was to quantify the safety performance of alternative traffic control strategies to mitigate right-turning vehicle-bicycle crashes at signalized intersections in Oregon. The ultimate aim was to provide useful design guidance to potentially mitigate these collision types at the critical intersection configurations. This report includes a comprehensive review of more than 150 scientific and technical articles that relate to bicycle-motor vehicle crashes. A total of 504 right-hook crashes were identified from vehicle path information in the Oregon crash data from 2007-2011, mapped and reviewed in detail to identify the frequency and severity of crashes by …


How To Estimate Pedestrian Demand, Kelly Clifton, Patrick Allen Singleton, Christopher D. Muhs, Robert J. Schneider Nov 2015

How To Estimate Pedestrian Demand, Kelly Clifton, Patrick Allen Singleton, Christopher D. Muhs, Robert J. Schneider

TREC Project Briefs

There is growing support to improve the quality of the walking environment and make investments to promote pedestrian travel. Such efforts often require analytical non-motorized planning tools to estimate levels of pedestrian demand that are sensitive to environmental and demographic factors at an appropriate scale. Despite this interest and need, current forecasting tools, particularly regional travel demand models, often fall short.

To address this gap, Oregon Metro and NITC researcher Kelly Clifton worked together to develop a pedestrian demand estimation tool. For generations, planners have been using statistical models to forecast travel demand, but these models have traditionally been auto-centered. …


High-Solids Anaerobic Digestion Of The Organic Fraction Of Municipal Solid Waste State Of The Art, Outlook In Florida, And Enhancing Methane Yields From Lignocellulosic Wastes, Gregory Richard Hinds Oct 2015

High-Solids Anaerobic Digestion Of The Organic Fraction Of Municipal Solid Waste State Of The Art, Outlook In Florida, And Enhancing Methane Yields From Lignocellulosic Wastes, Gregory Richard Hinds

USF Tampa Graduate Theses and Dissertations

Anaerobic digestion (AD) is a biotechnology that employs natural microbial metabolism under oxygen-free conditions to stabilize organic waste. AD has been shown to be the most environmentally sustainable technology for treating the organic fraction of municipal solid waste (OFMSW), as it allows for the recovery of energy and nutrients from the waste. AD of OFMSW also saves landfill space and reduces leachate generation and fugitive methane emissions from landfills. High-solids AD (HS-AD) technologies (those designed to process feedstocks with >15% total solids content) have been shown to yield additional benefits when compared with liquid AD (L-AD) for treating OFMSW, including …


Evaluation Of First Order Error Induced By Conservative-Tracer Temperature Approximation For Mixing In Karstic Flow, Philippe Machetel, David A. Yuen Oct 2015

Evaluation Of First Order Error Induced By Conservative-Tracer Temperature Approximation For Mixing In Karstic Flow, Philippe Machetel, David A. Yuen

Sinkhole Conference 2015

Fluid dynamics in karst systems is complex due to the heterogeneity of hydraulic networks that combine the Porous Fractured Matrix (PFM) and the interconnected drains (CS). These complex dynamic systems often need to be treated as “black boxes” in which only input and output properties are known. In this work, we propose to assess the first-order error induced by considering the temperature as a conservative tracer for flows mixing in karst (fluvio-karst). The fluvio-karstic system is treated as an open thermodynamic system (OTS), which exchanges water and heat with its surrounding. We propose to use a cylindrical PFM drained by …


Numerical Simulation Of Karst Soil Cave Evolution, Long Jia, Yan Meng, Zhende Guan, Lipeng Liu Oct 2015

Numerical Simulation Of Karst Soil Cave Evolution, Long Jia, Yan Meng, Zhende Guan, Lipeng Liu

Sinkhole Conference 2015

This study is focused on numerical simulation of the formation and development of karst soil caves related to cover-collapse sinkholes. The so-called ‘karst soil cave’ refers to the caves formed in the soil layers above bedrock of sinkhole regions. Because the soil caves are formed and developed under groundwater seepage, studying groundwater level changes can help understand soil cave development and collapse. Based on the improved Terzaghi loosening pressure theory and using excess pore water pressure, two kinds of critical groundwater level decline are discussed. The first, denoted as ∆H0, is the critical groundwater level decline related to soil cave …


Building Codes To Minimize Cover Collapses In Sinkhole-Prone Areas, George Veni, Connie Campbell Brashear, Andrew Glasbrenner Oct 2015

Building Codes To Minimize Cover Collapses In Sinkhole-Prone Areas, George Veni, Connie Campbell Brashear, Andrew Glasbrenner

Sinkhole Conference 2015

Cover- collapse sinkholes are forming with increasing frequency under buildings. Analyses of sinkhole distribution in Beacon Woods, Florida, preliminarily indicate their occurrence is an order of magnitude greater in urban versus undeveloped areas, suggesting the structures themselves are enhancing the collapse process. The most likely causes are induced recharge via at least one of two sources. First, runoff and drainage from roads, structures, and impoundments that is not adequately dispersed will promote sinkhole development. Second, leaking water, sewer, and septic systems beneath or adjacent to a structure will also promote collapse. The process of cover-collapse from induced recharge is well …


Hazard Of Sinkhole Flooding To A Cave Hominin Site And Its Control Countermeasures In A Tower Karst Area, South China, Fang Guo, Guanghui Jiang, Kwong Fai Andrew Lo, Qingjia Tang, Yongli Guo, Shaohua Liu Oct 2015

Hazard Of Sinkhole Flooding To A Cave Hominin Site And Its Control Countermeasures In A Tower Karst Area, South China, Fang Guo, Guanghui Jiang, Kwong Fai Andrew Lo, Qingjia Tang, Yongli Guo, Shaohua Liu

Sinkhole Conference 2015

Zengpiyan Cave, one of the most important cave hominin sites of the Neolithic in the South of China, was listed on the national register of cultural preservation sites in 2001. Large quantities of precious material in the Zengpiyan site were unearthed since the beginning of the trial excavation in 1973. These materials include hominin skeletal remains, fire pits, human burials, stone implements, tools fashioned from mollusk shells and animal or plant fossils. According to the historical record, ancient people lived in caves in the karst plain of Guilin. They moved out of the caves approximately 7000 years ago. These cave …


Study On Monitoring And Early Warning Of Karst Collapse Based On Botdr Technique, Zhende Guan Oct 2015

Study On Monitoring And Early Warning Of Karst Collapse Based On Botdr Technique, Zhende Guan

Sinkhole Conference 2015

Brilliouin Optical Time Domain Reflectometer (BOTDR) is a newly developed measurement and monitoring technique, which utilizes Brilliouin spectroscopy and Optical Time Domain Reflectometer (Jiang et al., 2006; Zhang et al., 2009; Xu et al.,2011) to measure strain generated in optical fibers as distributed in the longitudinal direction. This paper introduces the principle and characters of BOTDR technique firstly, and makes an example of karst collapse monitoring at section K14 of highway from Guilin to Yangshuo. And we talk about how to use this technique in underlying karst collapse monitoring in karst highway, discuss environmental factors, like temperature and vehicle dynamic …


Karst Spring Cutoffs, Cave Tiers, And Sinking Stream Basins Correlated To Fluvial Base Level Decline In South-Central Indiana, Garre A. Conner Oct 2015

Karst Spring Cutoffs, Cave Tiers, And Sinking Stream Basins Correlated To Fluvial Base Level Decline In South-Central Indiana, Garre A. Conner

Sinkhole Conference 2015

The Mitchell Aquifer averages 80m in thickness and underdrains a karst region in the Crawford Upland and Mitchell Plateau region in south-central Indiana (110,000 km2). The Springville Escarpment is a transitional boundary between the upland and plateau. Cave stream linking between cave tiers in the aquifer and correlation of cave tier inception horizons to a base level decline surface is interpreted for the Kirby Watershed, encompassing the prekarst headland of Indian Creek (42km2). The watershed was severed from lower Indian Creek at Eller Col by limestone cavern drainage on the ridge between White River and East Fork. Correlation of recharge …


Tracer Studies Conducted Nearly Two Decades Apart Elucidate Groundwater Movement Through A Karst Aquifer In The Frederick Valley Of Maryland, Keith A. White, Michael K. Cobb, Thomas Aley, Ethan Weikel Oct 2015

Tracer Studies Conducted Nearly Two Decades Apart Elucidate Groundwater Movement Through A Karst Aquifer In The Frederick Valley Of Maryland, Keith A. White, Michael K. Cobb, Thomas Aley, Ethan Weikel

Sinkhole Conference 2015

A pair of groundwater tracer studies at a single karst test site were completed 18 years apart. The results of these studies have provided evidence of both relatively rapid advective transport via conduits and an extreme capacity for dye storage and retardation. The tracer results, coupled with other subsurface investigation data, are used to develop a conceptual model for groundwater movement through this karst aquifer in the Frederick Valley of Maryland, as well as identify implications for remediation. Three fluorescent tracer dyes used in the initial study were detected in several background monitoring locations established for the second study conducted …


Integration And Delivery Of Interferometric Synthetic Aperture Radar [Insar] Data Into Stormwater Planning Within Karst Terranes, Brian Bruckno, Andrea Vaccari, Edward Hoppe, Scott Acton, Elizabeth Campbell Oct 2015

Integration And Delivery Of Interferometric Synthetic Aperture Radar [Insar] Data Into Stormwater Planning Within Karst Terranes, Brian Bruckno, Andrea Vaccari, Edward Hoppe, Scott Acton, Elizabeth Campbell

Department of Earth and Atmospheric Sciences: Faculty Publications

As part of two USDOT-funded studies focused on the development of satellite-based Interferometric Synthetic Aperture Radar (InSAR) technology, the researchers integrated InSAR-derived point cloud data into the transportation design process to optimize the location of a stormwater management system in a karst terrane. After initial validation, the InSAR data (over 1.67 million data points comprising various “scatterers”) were brought into a GIS dataframe and georeferenced to locations of known sinkholes. This dataset was then used to evaluate karst hazard within a 40x40km data frame located in the Valley and Ridge Province of Virginia. The group identified systematic kinematic differences in …


Techno-Economic Analysis Of Protein Concentrate Produced By Flash Hydrolysis Of Microalgae, Alexander Nana Yaw Asiedu Oct 2015

Techno-Economic Analysis Of Protein Concentrate Produced By Flash Hydrolysis Of Microalgae, Alexander Nana Yaw Asiedu

Civil & Environmental Engineering Theses & Dissertations

Process simulation and techno-economic analysis of 95wt.% protein concentrate from microalgae has been performed using SuperPro Designer v. 9.0. This work, first of its kind, is focused on the economic analysis of protein concentrate that includes processes such as microalgae cultivation, harvesting, protein extraction and drying steps. A baseline capacity of 160 MT/day protein concentrate production on commercial basis has been analyzed. This throughput requires 336 MT/day dry algae (54 wt.% protein). The amount of carbon dioxide required to grow this quantum of algae is estimated to be 648 MT/day, which is produced from an in situ 21 MW power …


Spatial Variability Of Subsurface Soil Conditions Causing Roadway Settlements, Ömer Bilgin, Kevin Arens, Mark Salveter, Alexander Dettloff Oct 2015

Spatial Variability Of Subsurface Soil Conditions Causing Roadway Settlements, Ömer Bilgin, Kevin Arens, Mark Salveter, Alexander Dettloff

Civil and Environmental Engineering and Engineering Mechanics Faculty Publications

Settlement of problematic soils constituting the roadway subgrade may result in pavement distress and structural failure, requiring periodic pavement patching and resurfacing. Many of these problems occur as a result of the settlement of soft cohesive and organic soils. Due to the extent of roadway projects and the limited frequency of boring locations, spatial variability of subsurface soil conditions, and sometimes due to an inadequate extent of exploration, these problematic soils may not be identified suitably during subsurface explorations. An extensive subsurface exploration program was implemented for detailed characterization of subsurface conditions for a relatively short section of an existing …


Comparing Nutrient Recovery Via Rapid (Flash Hydrolysis) And Conventional Hydrothermal Liquefaction Processes For Microalgae Cultivation, Caleb Richard Talbot Oct 2015

Comparing Nutrient Recovery Via Rapid (Flash Hydrolysis) And Conventional Hydrothermal Liquefaction Processes For Microalgae Cultivation, Caleb Richard Talbot

Civil & Environmental Engineering Theses & Dissertations

Algal biofuels have the potential to provide a scalable source of renewable fuels in the near future. The high nutrient use in algae cultivation and its recovery and recycling is one of the challenges that may limit the scalability and sustainability of algal biofuels. The present study evaluates the use of Hydrolysate obtained after Flash Hydrolysis (FH) of Scenedesmus at 280 C as a nutrient source for microalgae cultivation. FH Hydrolysate nutrient recycling was compared with low temperature batch Hydrothermal Liquefaction (HTL) nutrient recycling. Oocystis and Scenedesmus were cultivated using Hydrolysate as a partial phosphorous (P) and nitrogen (N) source. …


A Risk Assessment Of The Impacts Of Coastal Flooding And Sea Level Rise On The Existing And New Pump Stations 113, Norfolk, Va, David A. Pezza Oct 2015

A Risk Assessment Of The Impacts Of Coastal Flooding And Sea Level Rise On The Existing And New Pump Stations 113, Norfolk, Va, David A. Pezza

Civil & Environmental Engineering Theses & Dissertations

The author assessed the risk to a wastewater pump station and a planned replacement located nearby due to coastal flooding and rising sea levels. The locations for the pump stations are in the Larchmont neighborhood by the Lafayette River tidal estuaries in Norfolk, Virginia. The Lafayette River is a tributary to the Elizabeth River, which flows to the Chesapeake Bay. The low-lying areas along the river are subject to coastal surges caused by tropical and extra-tropical storms that flood the bay.

The region is considered one of the urban areas most exposed to the accelerating rate of rising sea levels. …


Recent Progress In Performance Evaluations And Near Real-Time Assessment Of Operational Ocean Products, Fabrice Hernandez, Edward Blockley, Gary B. Brassington, Fraser Davidson, Prasanth Divakaran, Marie Drévillon, Shiro Ishizaki, Marcos Garcia-Sotillo, Patrick J. Hogan, Priidik Lagemaa, Bruno Levier, Matthew Martin, Avichal Mehra, Christopher Mooers, Nicolas Ferry, Andrew Ryan, Charly Regnier, Alistair Sellar, Gregory C. Smith, Sarantis Sofianos, Todd Spindler, Gianluca Volpe, John Wilkin, Edward Zaron, Aijun Zhang Oct 2015

Recent Progress In Performance Evaluations And Near Real-Time Assessment Of Operational Ocean Products, Fabrice Hernandez, Edward Blockley, Gary B. Brassington, Fraser Davidson, Prasanth Divakaran, Marie Drévillon, Shiro Ishizaki, Marcos Garcia-Sotillo, Patrick J. Hogan, Priidik Lagemaa, Bruno Levier, Matthew Martin, Avichal Mehra, Christopher Mooers, Nicolas Ferry, Andrew Ryan, Charly Regnier, Alistair Sellar, Gregory C. Smith, Sarantis Sofianos, Todd Spindler, Gianluca Volpe, John Wilkin, Edward Zaron, Aijun Zhang

Civil and Environmental Engineering Faculty Publications and Presentations

Operational ocean forecast systems provide routine marine products to an ever-widening community of users and stakeholders. The majority of users need information about the quality and reliability of the products to exploit them fully. Hence, forecast centres have been developing improved methods for evaluating and communicating the quality of their products. Global Ocean Data Assimilation Experiment (GODAE) OceanView, along with the Copernicus European Marine Core Service and other national and international programmes, has facilitated the development of coordinated validation activities among these centres. New metrics, assessing a wider range of ocean parameters, have been defined and implemented in real-time. An …


The Contribution Of Syntrophic Fatty-Acid Degrading Microbial Communities To Anaerobic Digester Function And Stability, Prince Peter Mathai Oct 2015

The Contribution Of Syntrophic Fatty-Acid Degrading Microbial Communities To Anaerobic Digester Function And Stability, Prince Peter Mathai

Dissertations (1934 -)

Anaerobic digestion (AD), the conversion of complex organic matter to methane, occurs through a series of reactions mediated by different guilds of microorganisms. AD process imbalances, such as organic overload or high organic loading rates (OLR), can result in the accumulation of volatile fatty acids (VFA) e.g., propionate, which must be degraded to maintain stable reactor function. VFAs are metabolized by syntrophic fatty-acid degrading bacteria (SFAB) in association with methanogenic archaea (collectively, syntrophic microbial communities, SMC). Despite their indispensable role in AD, little is known about the ecology of SFAB, especially under stressed conditions. To facilitate ecological studies, four quantitative …


Heterogeneous Oxidation Of Catechol, Elizabeth A. Pillar, Ruixin Zhou, Marcelo I. Guzman Sep 2015

Heterogeneous Oxidation Of Catechol, Elizabeth A. Pillar, Ruixin Zhou, Marcelo I. Guzman

Chemistry Faculty Publications

Natural and anthropogenic emissions of aromatic hydrocarbons from biomass burning, agro-industrial settings, and fossil fuel combustion contribute precursors to secondary aerosol formation (SOA). How these compounds are processed under humid tropospheric conditions is the focus of current attention to understand their environmental fate. This work shows how catechol thin films, a model for oxygenated aromatic hydrocarbons present in biomass burning and combustion aerosols, undergo heterogeneous oxidation at the air–solid interface under variable relative humidity (RH = 0–90%). The maximum reactive uptake coefficient of O3(g) by catechol γO3 = (7.49 ± 0.35) × 10–6 occurs for …


The Effect Of Urbanization On The Embodied Energy Of Drinking Water In Tampa, Florida, Mark Vincent Eli Santana Sep 2015

The Effect Of Urbanization On The Embodied Energy Of Drinking Water In Tampa, Florida, Mark Vincent Eli Santana

USF Tampa Graduate Theses and Dissertations

Increasing urbanization has serious implications for resource and energy use. One of these resources is drinking water. The increased amount of impervious surfaces associated with urban development is responsible for increased runoff during rain events, which may have a negative impact on the quality of nearby bodies of water, including drinking water sources. The growing populations associated with urbanization require a higher water demand. In addition, urban drinking water systems use energy to collect, treat, and distribute a safe reliable effluent to users. Therefore, this study focuses on the degree to which urbanization influences the embodied energy of drinking water …


Energy Production And Effluent Quality In Tubular Digesters Treating Livestock Waste In Rural Costa Rica, Maureen Njoki Kinyua Sep 2015

Energy Production And Effluent Quality In Tubular Digesters Treating Livestock Waste In Rural Costa Rica, Maureen Njoki Kinyua

USF Tampa Graduate Theses and Dissertations

Use of tubular anaerobic digesters to treat livestock waste in developing countries has energy, agricultural, health, social and environmental benefits. However, careful use of digester effluent as a soil amendment is required due to the potential presence of protozoan parasites Cryptosporidium parvum and Giardia lamblia. This research investigated the performance of four tubular digesters in the Monteverde region of Costa Rica. High (>75%) volatile solids and BOD5 removal efficiencies were observed, which was attributed to the formation of a biologically active floccular sludge layer. Computational fluid dynamics (CFD) and bioprocess models were developed to evaluate the transport and transformation …


Environmental Sustainability Of Wastewater Treatment Plants Integrated With Resource Recovery: The Impact Of Context And Scale, Pablo K. Cornejo Sep 2015

Environmental Sustainability Of Wastewater Treatment Plants Integrated With Resource Recovery: The Impact Of Context And Scale, Pablo K. Cornejo

USF Tampa Graduate Theses and Dissertations

There is an urgent need for wastewater treatment plants (WWTPs) to adapt to a rise in water and energy demands, prolonged periods of drought, climate variability, and resource scarcity. As population increases, minimizing the carbon and energy footprints of wastewater treatment, while properly managing nutrients is crucial to improving the sustainability WWTPs. Integrated resource recovery can mitigate the environmental impact of wastewater treatment systems; however, the mitigation potential depends on various factors such as treatment technology, resource recovery strategy, and system size.

Amidst these challenges, this research seeks to investigate the environmental sustainability of wastewater treatment plants (WWTPs) integrating resource …


Sediment Loss And Its Cause In Puerto Rico Watersheds, Y. Yuan, Y. Jiang, E. V. Taugas, Eric G. Mbonimpa Sep 2015

Sediment Loss And Its Cause In Puerto Rico Watersheds, Y. Yuan, Y. Jiang, E. V. Taugas, Eric G. Mbonimpa

Faculty Publications

A major environmental concern in the Commonwealth of Puerto Rico is increased sediment load to water reservoirs, to estuaries, and finally to coral reef areas outside the estuaries. Sediment deposition has significantly reduced the storage capacity of reservoirs, and sediments, with their associated contaminants and nutrients that are adsorbed, can stress corals and negatively impact reef health. To prevent and manage sediment loss it is therefore important to understand local soil erosion and sediment transport processes. The main objective of this study was to determine the influence of landscape characteristics on sediment loss. We analyzed available precipitation and sediment data …


Ecoscience + Art Initiative: Designing A New Paradigm For College Education, Scholarship, And Service, Changwoo Ahn Sep 2015

Ecoscience + Art Initiative: Designing A New Paradigm For College Education, Scholarship, And Service, Changwoo Ahn

The Transdisciplinary STEAM+ Journal

The paper presents a new initiative, EcoScience + Art, which blooms at George Mason University. The creator explains the background, history, and recent activities of the initiative, and also introduces an on-going special project called “The Rain Project”, a student participatory project to design, construct, and monitor a green infrastructure (i.e., floating wetland) for sustainable stormwater management on campus. The special project is geared to design and present a new paradigm to integrate college education, scholarship, and service. The relevance of the initiative and the special project to STEAM education is discussed.


Household Bush Burning Practice And Related Respiratory Symptoms In Grenada, The Caribbean, Muge Akpinar-Elci, Kareem Coomansingh, James Blando, Larissa Mark Sep 2015

Household Bush Burning Practice And Related Respiratory Symptoms In Grenada, The Caribbean, Muge Akpinar-Elci, Kareem Coomansingh, James Blando, Larissa Mark

Center for Global Health Publications

The practice of household bush burning in Grenada occurs frequently, though it is not well documented. The effects of the emissions from bush burning on respiratory health of the population have never been researched in Grenada. The goal of the study was to measure the frequency of bush burning and to investigate the relationship between bush burning practice and respiratory health in Grenada. In this cross-sectional study, a questionnaire was used to gather information from households in the parishes of St. George and St. Andrew, Grenada. In total, 225 participants were recruited and their responses on household bush burning and …


Development Of A Pedestrian Demand Estimation Tool, Kelly Clifton, Patrick Allen Singleton, Christopher D. Muhs, Robert J. Schneider Sep 2015

Development Of A Pedestrian Demand Estimation Tool, Kelly Clifton, Patrick Allen Singleton, Christopher D. Muhs, Robert J. Schneider

Civil and Environmental Engineering Faculty Publications and Presentations

Most research on walking behavior has focused on mode choice or walk-trip frequency. In contrast, this study is one of the first to analyze the destination choice behaviors of pedestrians. Using about 4,500 walk trips from a 2011 household travel survey in the Portland, OR, region, we estimated multinomial logit pedestrian destination choice models for six trip purposes. Independent variables included terms for impedance (walk-trip distance); size (employment by type, households); supportive pedestrian environments (parks, a pedestrian index of the environment variable called PIE); barriers to walking (terrain, industrial-type employment); and traveler characteristics. Unique to this study was the use …


Comparisons Of Linear Regression Models For Properties Of Alkaliactivated Binder Concrete, Arkamitra Kar, Udaya B. Halabe, Indrajit Ray, Avinash Unnikrishnan Sep 2015

Comparisons Of Linear Regression Models For Properties Of Alkaliactivated Binder Concrete, Arkamitra Kar, Udaya B. Halabe, Indrajit Ray, Avinash Unnikrishnan

Civil and Environmental Engineering Faculty Publications and Presentations

Concrete with alkali-activated binder (AAB) is increasingly considered as a better alternative to conventional portland cement (PC) concrete due to its superior sustainable and green properties. In order to promote the practical usage of AAB concrete, a previous study by the present authors proposed models on correlations among their mechanical and nondestructive properties. The present study extends the previous knowledge by proposing new improved models using linear regressions to predict compressive strengths and modulus of elasticity from ultrasonic pulse velocities. The models are developed for both unstressed and stressed AAB concrete with different curing temperatures. The accuracies of the models …


A Study On Navigation Safety On Putou Branch Channel Extension Project For Meizhou Bay, Kui Zhao Aug 2015

A Study On Navigation Safety On Putou Branch Channel Extension Project For Meizhou Bay, Kui Zhao

Maritime Safety & Environment Management Dissertations (Dalian)

No abstract provided.


Recovery Of Nutrients From Animal And Human Wastes, Nathaniel E. Kallmyer, Zhe Sun, Kaitlin Harris, Zhi Zhou, Ernest R. Blatchley Iii Aug 2015

Recovery Of Nutrients From Animal And Human Wastes, Nathaniel E. Kallmyer, Zhe Sun, Kaitlin Harris, Zhi Zhou, Ernest R. Blatchley Iii

The Summer Undergraduate Research Fellowship (SURF) Symposium

Removal of nitrogen- and phosphorus-containing molecules from wastewater is necessary to prevent excessive growth of algae and resulting chemical changes to bodies of water. Of wastewater components, urine contains relatively high concentrations of nitrogen and phosphorus, the majority of which is ultimately present as ammonia and phosphate. Separation and stabilization of these nutrients may also allow for their reuse as fertilizer. Before the nutrients may be stored, they must be stabilized. At least a portion of ammonia-N must be converted to nonvolatile nitrogen. This may be achieved by using ammonia- and nitrite-oxidizing bacteria (AOB and NOB, respectively) to convert ammonia …


Membrane Pre-Treatment Using Chemical Disinfectants In Halide Impaired Waters, Holly M. Haflich, Kun Huang, Amisha D. Shah, John Howarter, Logan Kearney Aug 2015

Membrane Pre-Treatment Using Chemical Disinfectants In Halide Impaired Waters, Holly M. Haflich, Kun Huang, Amisha D. Shah, John Howarter, Logan Kearney

The Summer Undergraduate Research Fellowship (SURF) Symposium

The use of membrane filtration processes for desalination, water reuse, and water reclamation techniques are becoming more prevalent given freshwater shortages. However, the treatment of these waters is challenging because of the membranes used in these processes. During nanofiltration and reverse osmosis the membranes undergo biofouling. Reverse osmosis and nanofiltration are high-pressure membrane filtration techniques that treat seawater, brackish waters, and industrial wastewaters. Because of the biofouling, the polyamide thin film needs to be pretreated with chlorine (HOCl/ OCl-) as a disinfectant, but this damages the polyamide membrane. When the free chlorine is in the presence of halide-impaired waters, it …


Fluoride And Phosphate Removal From Industrial And Domestic Wastewaters Using Cerium Chloride, John Michael Gonzales Aug 2015

Fluoride And Phosphate Removal From Industrial And Domestic Wastewaters Using Cerium Chloride, John Michael Gonzales

UNLV Theses, Dissertations, Professional Papers, and Capstones

The use of cerium chloride (CeCl3) to remove fluoride and phosphate from waters is addressed in this study. High concentrations of fluoride exist in groundwater especially in developing countries. Consumption drinking water containing high levels of fluoride can lead to serious cases of dental and skeletal fluorosis. Current defluoridation technologies are limited, especially for high levels of fluoride, and are expensive. Industrial wastewaters contribute to the highest fluoride contamination in the world. With the increasing production of electronic materials, the global fluoride concentration and fluoride-contaminated waters have grown tremendously. Excessive discharge of phosphate into the environment promotes eutrophication of lakes …