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Articles 241 - 270 of 627

Full-Text Articles in Civil and Environmental Engineering

Impact Of Dynamic Message Signs On Driver Behavior Under Reduced Visibility Conditions, Ryan Selby Jan 2016

Impact Of Dynamic Message Signs On Driver Behavior Under Reduced Visibility Conditions, Ryan Selby

Electronic Theses and Dissertations

Fog along roadways is a dangerous hazard that leads to crashes resulting from limited visibility. Low visibility gives drivers less time to react to potential obstacles that can suddenly appear and require immediate action. To solve this issue, early warning systems involving Dynamic Message Signs or other types of devices are used to alert drivers of the impending visibility condition so that they are prepared. This research focuses on testing the effectiveness of one form of warning systems to investigate how it impacts driver behavior in foggy conditions. To accomplish this objective, a simulation study is developed to test variables …

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Using Fluorescence To Characterize Four Day Simulated Distribution System Trihalomethane Content In Florida Groundwaters, Jonathan Ousley Jan 2016

Using Fluorescence To Characterize Four Day Simulated Distribution System Trihalomethane Content In Florida Groundwaters, Jonathan Ousley

Electronic Theses and Dissertations

The United States Environmental Protection Agency (USEPA) regulates public water systems and has established limits for certain disinfection by products (DBPs) that have been linked to health effects, such as bladder cancer. The regulation of DBPs, specifically total trihalomethanes (TTHMs) and haloacetic acids (HAAs), have encouraged water treatment professionals to assess the type and amount of organic precursors in their supplies. Three of the more common water quality parameters that are monitored as DBP surrogates include dissolved organic carbon (DOC), ultraviolet absorbance (UV254), and specific ultraviolet absorbance (SUVA). Although DOC, UV254, and SUVA have been effectively correlated to DBP formation, …

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Experimental Study Of Sinkhole Failure Related To Groundwater Level Drops, Mohamed Alrowaimi Jan 2016

Experimental Study Of Sinkhole Failure Related To Groundwater Level Drops, Mohamed Alrowaimi

Electronic Theses and Dissertations

Sinkholes are natural geohazard phenomena that cause damage to property and may lead to loss of life. They can also cause added pollution to the aquifer by draining unfiltered water from streams, wetland, and lakes into the aquifer. Sinkholes occur in a very distinctive karst geology where carbonate, limestone, dolomite, or gypsum, are encountered as the bedrock that can naturally be dissolved by groundwater circulating through them. Sinkholes can occur gradually or suddenly with catastrophic impact depending on the geology and hydrology of the area. Predicting the formation and the collapse of a sinkhole based on the current ground investigation …

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Dynamic Modeling Approach To Quantify Change Orders Impact On Labor Productivity, Zain Al-Kofahi Jan 2016

Dynamic Modeling Approach To Quantify Change Orders Impact On Labor Productivity, Zain Al-Kofahi

Electronic Theses and Dissertations

In construction projects, change orders are commonly faced. These change orders, which are issued by the owner, may cause interruption to the contractor's work, resulting in damages such as loss of labor productivity, delay damages, and cost overruns which may lead to claims. The relationship between change orders and loss of labor productivity is not well understood because of the difficulty in linking the cause of the productivity loss to the change order. So, to receive compensation, the contractor needs to prove with a credible calculation that the productivity loss was a result of the change order issued by the …

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Control Of Metal-Release And Tuberculation In A Silica-Laden Groundwater Distribution System On The Volcanic Island Of Lana'i, Samantha Myers Jan 2016

Control Of Metal-Release And Tuberculation In A Silica-Laden Groundwater Distribution System On The Volcanic Island Of Lana'i, Samantha Myers

Electronic Theses and Dissertations

A corrosion control study for two distinct water distribution systems (WDS) has been completed for the Pulama Lana'i Water Company (Pulama). This project evaluated the use of chemical inhibitors to control corrosion and tuberculation within the Manele Bay WDS and the Lana'i City WDS. Pulama provides water to a population of 3,100 residents and is considering incorporating alternative water supplies in the future. Hence, knowing baseline corrosion rates within the WDS was desired. Several groundwater wells feed each of the WDS's; however, water quality between wells varies. Well water supplied to the WDS's is generally of high quality, therefore, the …

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Joint Modeling Of Traffic Related Crashes: A Copula Based Approch, Tammam Nashad Jan 2016

Joint Modeling Of Traffic Related Crashes: A Copula Based Approch, Tammam Nashad

Electronic Theses and Dissertations

The study contributes to safety literature on transportation safety by employing copula based models for count frequency analysis at a macro-level. Most studies in the transportation safety area identify a single count variable (such as vehicular, pedestrian or bicycle crash counts) for a spatial unit and study the impact of exogenous variables. While the traditional count models perform adequately in the presence of a single count variable, it is necessary to modify these approaches to examine multiple dependent variables for each study unit. To that extent, the current research effort contributes to literature by developing two multivariate models based on …

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Analysis Of Driving Behavior At Expressway Toll Plazas Using Driving Simulator, Moatz Saad Jan 2016

Analysis Of Driving Behavior At Expressway Toll Plazas Using Driving Simulator, Moatz Saad

Electronic Theses and Dissertations

The objective of this study is to analyze the driving behavior at toll plazas by examining multiple scenarios using a driving simulator to study the effect of different options including different path decisions, various signs, arrow markings, traffic conditions, and extending auxiliary lanes before and after the toll plaza on the driving behavior. Also, this study focuses on investigating the effect of drivers' characteristics on the dangerous driving behavior (e.g. speed variation, sudden lane change, drivers' confusion). Safety and efficiency are the fundamental goals that transportation engineering is always seeking for the design of highways. Transportation agencies have a crucial …

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The Effect Of Glycerol On Readily Biodegradable Chemical Oxygen Demand (Rbcod) In A Wastewater Stream, Rojina Rawut Jan 2016

The Effect Of Glycerol On Readily Biodegradable Chemical Oxygen Demand (Rbcod) In A Wastewater Stream, Rojina Rawut

Electronic Theses and Dissertations

This study evaluated the short-term effects of glycerol addition on readily biodegradable (RB) chemical oxygen demand (COD) in a carbon limited wastewater influent. The presence of an RB fraction provides with a suitable substrate for microorganisms to produce volatile fatty acids (VFA). The oxygen utilization rate (OUR) has been used to evaluate the oxygen consumption for RB substrate in wastewater. Wastewater with low organic content contains limited RB substrate, and thus, additional carbon source is required to improve biological treatment capability. Acetate, propionate, methanol, and glycerol are the commonly available carbon sources for biological treatment process. However, the cost of …

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Integrating Spray Aeration And Granular Activated Carbon For Disinfection By-Product Control In A Potable Water System, Angela Rodriguez Jan 2016

Integrating Spray Aeration And Granular Activated Carbon For Disinfection By-Product Control In A Potable Water System, Angela Rodriguez

Electronic Theses and Dissertations

Public water systems add disinfectants in water treatment to inactivate microbial pathogens. Chlorine, when used as a disinfectant, reacts with natural organic matter in the water to form trihalomethane (THM) and haloacetic acid (HAA5) disinfection by-products (DBPs), which are suspected carcinogens. The Safe Drinking Water Act's Disinfectant and Disinfection By-Product (D/DBP) Rules were promulgated by the U.S. Environmental Protection Agency to regulate the amount of DBPs in water systems. Regulatory compliance is based on maximum contaminant levels (MCL), measured as a locational running annual average (LRAA), for total THM (TTHM) and HAA5 of 80 µg/L and 60 µg/L, respectively. Regulated …

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The Effect Of Recycled Backwash Water Operations On Fouling In A Coagulation-Ultrafiltration Process And Impact Of Preozonation On Membrane Productivity, Paul Biscardi Jan 2016

The Effect Of Recycled Backwash Water Operations On Fouling In A Coagulation-Ultrafiltration Process And Impact Of Preozonation On Membrane Productivity, Paul Biscardi

Electronic Theses and Dissertations

This dissertation consists of research that focused on pretreatment strategies to reduce fouling of ultrafiltration (UF) membranes used for drinking water treatment, and was segmented into four key components. (1) In the first component of the work, the long-term fouling behavior of a polyethersulfone (PES) hollow-fiber UF membrane was studied at the pilot-scale for treatment of surface water over a one-year period. Pilot testing of a coagulation-flocculation-sedimentation (CFS) pretreatment system revealed that chemically irreversible fouling was poorly correlated with turbidity and total organic carbon. It was also shown that recycled backwash water may have impacted membrane process performance, and that …

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Anthropogenic Organic Chemical Removal From A Surficial Groundwater And Mass Transfer Modeling In A Nanofiltration Membrane Process, Samantha Black Jan 2016

Anthropogenic Organic Chemical Removal From A Surficial Groundwater And Mass Transfer Modeling In A Nanofiltration Membrane Process, Samantha Black

Electronic Theses and Dissertations

This dissertation reports on research related to trace organic compounds (TrOCs) in surficial groundwater supplies and their subsequent removal from nanofiltration (NF) membranes. The research was conducted along coastal South Florida in cooperation with the Town of Jupiter Water Utilities, Jupiter, FL (Town). The focus of the research was to determine the extent of reclaimed water impacts on surficial groundwater supplies and subsequent effects on the Town's NF water treatment plant. Routine monitoring of fourteen TrOCs in reclaimed water and at the water treatment facility revealed varying degrees of TrOC detection in the environment. Certain TrOCs, including caffeine and DEET, …

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An Integrated Hydrodynamic-Marsh Model With Applications In Fluvial, Marine, And Mixed Estuarine Systems, Karim Alizad Jan 2016

An Integrated Hydrodynamic-Marsh Model With Applications In Fluvial, Marine, And Mixed Estuarine Systems, Karim Alizad

Electronic Theses and Dissertations

Coastal wetlands experience fluctuating productivity when subjected to various stressors. One of the most impactful stressors is sea level rise (SLR) associated with global warming. Research has shown that under SLR, salt marshes may not have time to establish an equilibrium with sea level and may migrate landward or become open water. Salt marsh systems play an important role in the coastal ecosystem by providing intertidal habitats and food for birds, fish, crabs, mussels, and other animals. They also protect shorelines by dissipating flow and damping wave energy through an increase in drag forces. Due to the serious consequences of …

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Getting To Net Zero Energy Buildings: A Holistic Techno-Ecological Modeling Approach, Mehdi Alirezaei Jan 2016

Getting To Net Zero Energy Buildings: A Holistic Techno-Ecological Modeling Approach, Mehdi Alirezaei

Electronic Theses and Dissertations

Buildings in the United States are responsible for more than 40% of the primary energy and 70% of electricity usage and greatly in CO2 emission by about 39%, more than any other sector including transportation and industry sectors. This energy consumption is expected to grow mainly due to increasing trends in new buildings construction. Rising energy prices alongside with energy independencies, limited resources, and climate change have made the current situation even worse. An Energy Efficient (EE) building is able to reduce the heating and cooling load significantly compared with a code compliant building. Furthermore, integrating renewable energy sources in …

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Estimating A Freight Mode Choice Model: A Case Study Of Commodity Flow Survey 2012, Nowreen Keya Jan 2016

Estimating A Freight Mode Choice Model: A Case Study Of Commodity Flow Survey 2012, Nowreen Keya

Electronic Theses and Dissertations

This research effort develops a national freight mode choice model employing data from the 2012 Commodity Flow Survey (CFS). While several research efforts have developed mode choice model with multiple modes in the passenger travel context, the literature is sparse in the freight context. The primary reasons being unavailability and/or the high cost associated with the acquisition of mode choice and level of service (LOS) measures – such as travel time and travel cost. The first contribution of the research effort is to develop travel time and cost measures for various modes reported in the CFS. The study considers five …

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Application Of Landfill Treatment Approaches For The Stabilization Of Municipal Solid Waste, Stephanie Bolyard Jan 2016

Application Of Landfill Treatment Approaches For The Stabilization Of Municipal Solid Waste, Stephanie Bolyard

Electronic Theses and Dissertations

This research focused on the fundamental requirements of stabilizing a mature landfill using three treatment approaches as well as the implications of discharging leachate organic matter (LOM) to wastewater treatment plants (WWTPs). Three treatment approaches aimed at removing releasable carbon and nitrogen from mature landfills including flushing with clean water, leachate recirculation with ex-situ chemical oxidation, and leachate recirculation with ex-situ chemical oxidation and in-situ aeration were evaluated. After extensive treatment of the waste in the flushing bioreactor (FB) scenarios, the overall biodegradable fraction was reduced relative to mature waste. Leachate quality improved for all FBs but through different mechanisms. …

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Structural Health Monitoring Of Composite Overwrapped Pressure Vessels, Luca Letizia Jan 2016

Structural Health Monitoring Of Composite Overwrapped Pressure Vessels, Luca Letizia

Honors Undergraduate Theses

This work is focusing to study the structural behavior of Composite Overwrapped Pressure Vessels (COPVs). These COPVs are found in many engineering applications. In the aerospace field, they are installed onto spaceships and aid the reorientation of the spacecraft in very far and airless, therefore frictionless, orbits to save energy and fuel. The intent of this research is to analyze the difference in performance of both perfectly intact and purposely damaged tanks. Understanding both the source and location of a structural fault will help NASA engineers predict the performance of COPVs subject to similar conditions, which could prevent failures of …

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Evaluation Of Real World Toll Plazas Using Driving Simulation, Kali Carroll Jan 2016

Evaluation Of Real World Toll Plazas Using Driving Simulation, Kali Carroll

Electronic Theses and Dissertations

Toll plazas are becoming an essential part of the highway system, especially within the state of Florida. Many crashes reported on highways occur at toll plazas. A primary reason for many vehicle collisions happening at these facilities is the fact that each toll plaza agency has different design, signage and marking criteria. This, in turn, causes driver confusion and possible last minute weaving maneuvers. Even though the varying design of toll plazas is a clear highway safety factor, research in the field is very limited but expanding. This study focuses on one toll plaza, in particular the Dean Mainline Toll …

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Impact Of The Longer Change And Clearance Intervals On Signalized Intersections And Corridors, Mohammed Alfawzan Jan 2016

Impact Of The Longer Change And Clearance Intervals On Signalized Intersections And Corridors, Mohammed Alfawzan

Electronic Theses and Dissertations

Evaluating the impact of longer change and clearance intervals on signalized intersections and corridors is the main goal of this study. In fact, the Florida department of Transportation (FDOT) has adopted a new signal retiming effort in a number of signalized intersections along several corridors. The Orange County started implementing the new signal timing from December, 2013 and completed it in June, 2015. The other objective of this new signal timing is to minimize the red light running rate. This study is dedicated to investigate the signal retiming effort adopted by the FDOT and how the new signal timing might …

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Determining The Feasibility Of Using Micro Simulation To Asses Safety Of Pedestrian Crossings, Jenner Darius Jan 2016

Determining The Feasibility Of Using Micro Simulation To Asses Safety Of Pedestrian Crossings, Jenner Darius

Electronic Theses and Dissertations

For the past several decades, pedestrian safety has been an oncoming issue that has thrown the area of transportation engineering into a frenzy. Pedestrian safety has become predominantly one of the leading causes of fatalities in traffic accidents. Florida has been reported as one of the leading states in pedestrian fatalities with 2.56 fatality rate per 100,000 population and about 20 percent of all traffic fatalities in the state of Florida. Nonetheless, as research is being done and hypotheses are being calibrated and produced, there has to be a way of measuring and determining the number of pedestrian-to-vehicle conflicts without …

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The Effect Of Building Information Modeling On Design And Construction Industry, Yahya Alassaf Jan 2016

The Effect Of Building Information Modeling On Design And Construction Industry, Yahya Alassaf

Electronic Theses and Dissertations

Construction industry's evolution is, historically, in the lowest level, if compared to other industries, such as auto manufacturing. Construction is a multidisciplinary industry, considering that designers, contractors, and owners are all involved in the same project, each one seeking their own interests. The complex environment surrounding design and construction makes the decision-makers hesitate about adopting new methodology. Building Information Modeling (BIM) is a new method and technology, which can improve both the design and the construction processes. The adoption of BIM is increasing significantly over the last years, and its effects can be seen on real life projects. In order …

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Remote Sensing Of Coastal Wetlands: Long Term Vegetation Stress Assessment And Data Enhancement Technique, Subrina Tahsin Jan 2016

Remote Sensing Of Coastal Wetlands: Long Term Vegetation Stress Assessment And Data Enhancement Technique, Subrina Tahsin

Electronic Theses and Dissertations

Apalachicola Bay in the Florida panhandle is home to a rich variety of salt water and freshwater wetlands but unfortunately is also subject to a wide range of hydrologic extreme events. Extreme hydrologic events such as hurricanes and droughts continuously threaten the area. The impact of hurricane and drought on both fresh and salt water wetlands was investigated over the time period from 2000 to 2015 in Apalachicola Bay using spatio-temporal changes in the Landsat based NDVI. Results indicate that salt water wetlands were more resilient than fresh water wetlands. Results also suggest that in response to hurricanes, the coastal …

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Effects Of Climate Change And Anthropogenic Activities On The Everglades Landscape., Daljit Sandhu Jan 2016

Effects Of Climate Change And Anthropogenic Activities On The Everglades Landscape., Daljit Sandhu

Electronic Theses and Dissertations

The Everglades has been experiencing major changes, both climatic and anthropogenic, such that the landscape is experiencing additional stresses and forcings leading it away from its natural equilibrium. The land within and surrounding the Everglades has undergone severe modifications that may have detrimental effects on wildlife and natural features, such as rivers and landscape connectivity. Here in this study, the main focus is on understanding and quantifying hydrologic and geomorphic signatures of climatic and anthropogenic changes on the Everglades landscape. For this, in particular, available data on natural hydrological processes was used, such as rainfall, groundwater elevation, streamflow as well …

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Sinkhole Monitoring Using Groundwater Table Data, Ton Tu Jan 2016

Sinkhole Monitoring Using Groundwater Table Data, Ton Tu

Electronic Theses and Dissertations

Florida might be one of the most sinkhole-active areas on the earth. Due to its unpredictability and significance of occurrence, the development of sinkhole monitoring techniques is imperative to minimize sinkhole-induced hazards. Several methods have been used to evaluate sinkhole risks, including destructive methods, such as Standard Penetrating Tests (SPT) and Cone Penetrating Tests (CPT), geophysical method, and sensor-based groundwater monitoring method. However, few studies are available for comprehensive understanding of spatiotemporal sinkhole mechanism by combining different exploration methods under realistic experimental conditions. The objective of this study is to understand spatiotemporal sinkhole mechanism, using SPT, CPT, ground penetrating radar …

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Mechanistic Behavior Of Uhpc And Uhpc Composite Structural Components, Munaf Al-Ramahee Jan 2016

Mechanistic Behavior Of Uhpc And Uhpc Composite Structural Components, Munaf Al-Ramahee

Electronic Theses and Dissertations

The resistance of reinforced concrete is mobilized through the composite action of two materials with different mechanical behaviors and physical features. Enabling the composite action requires a transfer mechanism between the concrete and the reinforcement which is referred to as bond. The bond model can be defined as a traction-slip relation tangent to the interface. The bond strength between different types of concrete, internal reinforcement, and external reinforcement has been of interest to structural engineers for decades. Experimental tests have been carried out to validate the existing bond models and introduce new bond models for special cases of concrete or …

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Modeling Wastewater Indicators And Effects Of Contaminant Removal Strategies On Groundwater And Spring Discharge In A Karst Aquifer, Erin Reed Jan 2016

Modeling Wastewater Indicators And Effects Of Contaminant Removal Strategies On Groundwater And Spring Discharge In A Karst Aquifer, Erin Reed

Electronic Theses and Dissertations

This dissertation reports on research related to groundwater and contaminant transport to the Volusia Blue Spring (VBS), an Outstanding Florida Water Body located in Volusia County (Florida). The integration of springshed water quality and contaminant fate and transport (CFT) modeling played key roles in the evaluation of anthropogenic recharge impacts on VBS. To study anthropogenic recharge into the karst limestone aquifer, wastewater effluent, golf course ponds, septic tanks, groundwater monitoring wells, and VBS discharge were sampled for boron, nitrate-nitrogen, nitrate-oxygen and their isotopes spatially throughout the VBS springshed. Data related to natural water features, rainfall, land use, water use, treated …

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Microscopic Safety Evaluation And Prediction For Special Expressway Facilities, Ling Wang Jan 2016

Microscopic Safety Evaluation And Prediction For Special Expressway Facilities, Ling Wang

Electronic Theses and Dissertations

Expressways are of great importance and serve as the backbone of a roadway system. One of the reasons why expressways increase travel speeds and provide high level of services is that limited access is provided to permit vehicles to enter or exit expressways. Entering and exiting of vehicles are accomplished through interchanges, which consist of several ramps, thus the spacing between ramps is important. A weaving segment might form when an on-ramp is closely followed by an off-ramp. The geometric design of ramps and the traffic behavior of weaving segments are different from other expressway segments. These differences result in …

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Evaluating Wrong-Way Driving For Florida Interstates And Toll Road Facilities: A Risk-Based Investigation, And Countermeasure Development, John Rogers Jan 2016

Evaluating Wrong-Way Driving For Florida Interstates And Toll Road Facilities: A Risk-Based Investigation, And Countermeasure Development, John Rogers

Electronic Theses and Dissertations

The focus of this dissertation was to examine wrong-way driving (WWD) events on Florida toll roads and Interstates. The universe of WWD data contains many sources of WWD events or incidents. Most of the previous research focused only on WWD crashes without considering other data such as WWD citations and 911 calls related to WWD incidents. While WWD citations and 911 calls data is abundant, this data has been largely overlooked in other studies. This dissertation provides a novel and holistic approach for evaluating WWD risk, which considers other risk factors such as WWD citations and 911 calls in addition …

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Evaluation Of Crash Modification Factors And Functions Including Time Trends At Intersections, Jung-Han Wang Jan 2016

Evaluation Of Crash Modification Factors And Functions Including Time Trends At Intersections, Jung-Han Wang

Electronic Theses and Dissertations

Traffic demand has increased as population increased. The US population reached 313,914,040 in 2012 (US Census Bureau, 2015). Increased travel demand may have potential impact on roadway safety and the operational characteristics of roadways. Total crashes and injury crashes at intersections accounted for 40% and 44% of traffic crashes, respectively, on US roadways in 2007 according to the Intersection Safety Issue Brief (FHWA, 2009). Traffic researchers and engineers have developed a quantitative measure of the safety effectiveness of treatments in the form of crash modification factors (CMF). Based on CMFs from multiple studies, the Highway Safety Manual (HSM) Part D …

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Investigation Of Infrared Thermography For Subsurface Damage Detection Of Concrete Structures, Shuhei Hiasa Jan 2016

Investigation Of Infrared Thermography For Subsurface Damage Detection Of Concrete Structures, Shuhei Hiasa

Electronic Theses and Dissertations

Deterioration of road infrastructure arises from aging and various other factors. Consequently, inspection and maintenance have been a serious worldwide problem. In the United States, degradation of concrete bridge decks is a widespread problem among several bridge components. In order to prevent the impending degradation of bridges, periodic inspection and proper maintenance are indispensable. However, the transportation system faces unprecedented challenges because the number of aging bridges is increasing under limited resources, both in terms of budget and personnel. Therefore, innovative technologies and processes that enable bridge owners to inspect and evaluate bridge conditions more effectively and efficiently with less …

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Modeling Mass Transfer And Assessing Cost And Performance Of A Hollow Fiber Nanofiltration Membrane Process, David Yonge Jan 2016

Modeling Mass Transfer And Assessing Cost And Performance Of A Hollow Fiber Nanofiltration Membrane Process, David Yonge

Electronic Theses and Dissertations

Bench-scale water treatment testing of three next generation hollow-fiber (HF) nanofiltration (NF) membranes was conducted to characterize divalent ion rejection capabilities and investigate removal mechanisms. Existing mathematical models were investigated to describe solute transport using synthetic magnesium sulfate solutions including the size exclusion model, homogenous solution diffusion (HSD) model, dimensional analysis, and the HSD model incorporating film theory. Solute transport for two of the membranes were described by HSD theory and were predictive of their 90% divalent ion removal. A third membrane was more accurately modeled using size exclusion and was found to be predictive of its 40% divalent ion …

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