Civil and Environmental Engineering Commons^™

Factors Influencing Demand For Buses Powered By Alternative Energy Sources, Janer Galván, Victor Cantillo, Julian Arellana

Journal of Public Transportation

Transit buses consume high amounts of fossil fuels, with the consequent release of greenhouse gases into the atmosphere. In recent decades, much effort has been concentrated on the development of cleaner fuels to mitigate this externality. However, market shares for cleaner-fueled buses are still modest, which is why it is relevant to evaluate the aspects influencing their acceptance. This article presents an econometric model to evaluate factors influencing demand for transit buses in Colombia powered by cleaner fuels. For this purpose, a stated preference survey was applied to public transportation entrepreneurs. Results suggest that the target population considers acquisition cost …

A Composite Index For Evaluating Transit Service Quality Across Different User Profiles, Juan De Oña, Rocio De Oña, Francisco Diez-Mesa, Laura Eboli, Gabriella Mazzulla

Journal of Public Transportation

This paper evaluates the quality of service of the metropolitan Metro of Seville (Spain) across different user profiles, as determined through cluster analysis. Service quality evaluation is performed using a composite index that combines the user point of view with the service operator point of view. The combination of these two types of service quality measurement fulfils the need to provide a reliable measurement tool for transit performance. Six user profiles were identified, and it was ascertained that they have different opinions about the service, with heterogeneous gaps between the points of view among the six user profiles.

Examining Bus Lost Time Dynamics For A Bus Rapid Transit Station, Ankit Kathuria, M. Parida, Ch. Ravi Sekhar, Manu Pathak

Journal of Public Transportation

Bus Rapid Transit (BRT) systems are considered to be the most effective alternative for solving urban transportation problems for both developed and developing countries. The conventional approach to estimate dwell time (DT) is based on traditional DT models derived for normal bus stops, but not for modern BRT stations. BRT stations are different from bus stops in terms of length of platform, multiple loading areas, and number of passengers handled. Therefore, understanding dwell time dynamics, including the recently-introduced component of Bus Lost Time (BLT), is important to improve the operations of BRT systems. This research introduces various possible scenarios of …

Planning For Climate Change: The Need For Mechanistic Systems-Based Approaches To Study Climate Change Impacts On Diarrheal Diseases, Jonathan E. Mellor, Karen Levy, Julie Zimmerman, Mark Elliott, Jamie Bartram, Elizabeth Carlton, Thomas Clasen, Rebecca Dilingham, Joseph Eisenberg, Richard Guerrant, Daniele Lantagne, James Mihelcic, Kara Nelson

Civil and Environmental Engineering Faculty Publications

Increased precipitation and temperature variability as well as extreme events related to climate change are predicted to affect the availability and quality of water globally. Already heavily burdened with diarrheal diseases due to poor access to water, sanitation and hygiene facilities, communities throughout the developing world lack the adaptive capacity to sufficiently respond to the additional adversity caused by climate change. Studies suggest that diarrhea rates are positively correlated with increased temperature, and show a complex relationship with precipitation. Although climate change will likely increase rates of diarrheal diseases on average, there is a poor mechanistic understanding of the underlying …

In-Situ Testing Of Uretek's Injectable BarrierSm As A Mechanism For Groundwater Control, Jeremy Hess

USF Tampa Graduate Theses and Dissertations

Construction projects involving the installation or repair of subsurface structures or utilities often require dewatering to induce a temporary lowering of the local groundwater elevation to facilitate construction. In the event that a known contaminant plume is present in an adjacent area, this dewatering may inadvertently draw the contaminant into the previously uncontaminated work area. Uretek Holdings, Inc. has developed its Injectable Barrier^SM to be installed prior to dewatering exercises to provide a groundwater cut-off by reducing the potential movement of groundwater due to the hydraulic gradient induced by dewatering. A benefit of Injectable Barrier^SM as compared to …

Sizing An Anaerobic Digester In A Rural Developing World Community: Does Household Fuel Demand Match Greenhouse Gas Production?, Ronald Keelan Greenwade

USF Tampa Graduate Theses and Dissertations

Anaerobic digestion is the process by which organic carbon is converted into biogas in the form of carbon dioxide (CO₂) and methane (CH₄). Both of these products are greenhouse gases that contribute to global warming. Therefore if anaerobic reactors are improperly maintained and biogas is leaked or intentionally released into the atmosphere because biogas production exceeds household demand, these reactors may become generators of greenhouse gas emissions instead of sustainable energy producers. The objective of this research was to develop a framework to assess if the demand for biogas by a rural adopter of an anaerobic …

Application Of Spatial And Descriptive Analysis Methods To Determine Relationship Between Hardware Subsidies And The Sanitation Marketplace, Danielle Devuyst

USF Tampa Graduate Theses and Dissertations

Sanitation marketing is an emerging approach of strengthening the local private sector to implement scalable and sustainable improved sanitation coverage in developing countries, specifically among the poor. It encourages the enhancement of sanitation market supply and demand by developing distribution infrastructure and stimulating consumer interest. Unlike interventions that provide hardware subsidies to initiate sanitation demand, financial support for sanitation marketing is used exclusively for the research and development of the market; this encourages the private sector to become independent and self-sufficient. Qualitative data suggests that while sanitation marketing projects have been successful at implementing replicable and sustainable sanitation coverage, they …

Adoption Of The Sawyer Water Filter In Peru, Stephanie D. Paredes

USF Tampa Graduate Theses and Dissertations

In Peru, lack of water, sanitation, and hygiene (WASH) results in 6,600 deaths per year that represents approximately 3.9% of total deaths. Three thousand and nine hundred of these deaths were due to diarrheal diseases (Prüss-Üstün et al., 2008). Systematic reviews suggest that interventions to improve microbial quality of drinking water are successful in reducing diarrheal diseases (Fewtrell et al., 2005; Clasen et al., 2007; Fry et al., 2013). Interventions for household water treatment and safe storage to ensure safe drinking water reduce diarrhea by 31-52% (WHO/UNICEF, 2013).

The SAWYER PointONE filter, a portable and adaptable membrane filtration device as …

Water Metering In Rural, Piped, Community-Managed Water Systems In The Developing World, Simona Platukyte

USF Tampa Graduate Theses and Dissertations

In the early 1990s, the United Nations (UN) recognized water as a finite resource to the entire ecosystem with an economic value that should be developed and managed based on the participatory approach using the Integrated Water Resource Management (IWRM) strategy. Many studies on water management practices have thus emerged in the developing world. Of particular interest to this work is the management of water through metering, price-setting, and rule enforcement in the rural setting in piped, community-owned water systems. There is very little published information regarding metering, enforcement experiments, and experiences in these systems. This is because metering and …

Experimental Studies Of Simultaneous Nitrification Denitrification And Phosphorus Removal At Falkenburg Advanced Wastewater Treatment Plant, Ann Elizabeth Sager

USF Tampa Graduate Theses and Dissertations

The discharge of point- and non-point source pollutants into surface waters resulting from industrial and/or municipal activities is a major focus of environmental regulation in the United States. As a result, the National Pollutant Discharge Elimination System (NPDES) permit program was established in 1972 in an effort to regulate discharges from industrial or municipal sources, including wastewater treatment plants (WWTP). To further protect Florida water quality, in 1978, State legislation enacted the Grizzle-Figg Act for Tampa Bay, which requires advanced wastewater treatment for any discharge into sensitive water bodies. A common use of wastewater effluent in the Tampa Bay area …

Cement Heat Of Hydration And Thermal Control, Ahmadreza Sedaghat

USF Tampa Graduate Theses and Dissertations

Heat of hydration is a property of Portland cement and a direct result of the chemical reaction between cement and water. The amount of heat released is dependent upon the cement mineralogical composition, curing temperature, water to cement ratio, and cement fineness. High temperature resulting from heat of hydration (thereon referred to as HOH) of cement can affect the hydration process, and consequently the kinetics of development of the mechanical properties of concrete. One of the main reasons triggering the interest in HOH of cement is its implication in thermal cracking of concrete. The high temperature gradient between the inner …

Modeling The Extent Of Virus Removal In Waste Stabilization Ponds To Support Reuse Of Wastewater, Kelly James Vannoy

USF Tampa Graduate Theses and Dissertations

Waste stabilization ponds (WSPs) are one of the most prevalent types of domestic wastewater treatment technologies employed worldwide, and global stressors such as urbanization, population growth, climate change, and water scarcity have increased the demand for reusing treated wastewater. The safe reuse of treated wastewater in agriculture can ease water scarcity, aid in food production, and reduce environmental degradation from the discharge of wastewater effluent to surface waters. The ability to predict virus concentrations in wastewater effluent is an important criterion for determining whether wastewater is suitable for discharge to the environment or for reuse in agriculture. However, many uncertainties …

Full Scale Evaluation Of Organic Soil Mixing, Kelly Costello

USF Tampa Graduate Theses and Dissertations

Soil mixing is a procedure that has proven to be effective for loose or soft compressible soils. The method stabilizes the soil in-place using specialized augers, tillers, or paddles that inject grout or dry cementitious powders as part of the mixing process. The Federal Highway Administration design manual for soil mixing helps to estimate the required amount of cementitious binder to produce a target design strength. However, it is biased towards inorganic soils and only mentions caution when confronting organic soils which usually come with a high water table, moisture content and void volume.

The Swedish Deep Stabilization Research Centre …

Increasing The Capacities Of Cable Cars For Use In Public Transport, Sergej Težak, Drago Sever, Marjan Lep

Journal of Public Transportation

This paper examines the advantages and disadvantages of cable cars in public transport within urban areas. The advantages of cable car transport compared to other modes of transport are its quiet operation with an environmentally-acceptable electric drive and the possibility of transporting passengers above the ground, which can provide additional transport dimensions within urban centers. However, cable cars have some disadvantages, especially their smaller capacities in relation to other modes of transport within the urban environment. Today's built cable cars have capacities up to 2,000 persons/h for aerial tramways (or jig-back ropeways) and up to 4,000 persons/h for gondolas.

Solutions …

Willingness To Use A Public Bicycle System: An Example In Nanjing City, Peiyu Feng, Wenquan Li

Journal of Public Transportation

The purpose of this paper is to examine the influence factors on willingness to use a public bicycle system and to analyze the impact of each. Ordered Logit and Probit models were used to analyze the change in user willingness after improvements were made. Data were collected from a random survey conducted in September and October 2014 in Nanjing, China. The findings of this research indicate seven factors that most influence willingness to use a public bicycle system, including socioeconomic factors and journey restrictions. Socioeconomic factors (gender, employment, and car ownership) have more impact on user willingness than journey restrictions. …

The Effects Of Access And Accessibility On Public Transport Users’ Attitudes, Subeh Chowdhury, Kasey Zhai, Asif Khan

Journal of Public Transportation

This study investigates existing users’ attitudes towards public transport from two perspectives. First, the effects of accessibility to various destinations and ease of access to terminals on public transport users’ attitudes are determined. Second, the contribution of social norm, as an information source, in the formation of users’ attitudes is assessed. A user-preference survey was undertaken in Auckland, New Zealand, at two terminals. Data were analyzed using ordinal and logistic regression models. Findings showed that residential density and quality of the built environment, particularly safety, have an effect on the number of pedestrians who access a terminal. Accessibility to various …

Coupling Community Preferences With Hydrologic Evaluation Of Low Impact Development Implementation In An Urban Watershed, Corinna M. Fleischmann, Carol Atkinson-Palombo, Joseph T. Bushey, Eric D. Jackson, David W. Payne

Suburban Sustainability

Stormwater runoff, and its associated pollutants, is a major problem in urban watersheds where the runoff is either channeled into surface water bodies or wastewater treatment plants. One emerging Best Management Practice (BMP) to control stormwater runoff is low impact development (LID). The EPA Stormwater Management Model (SWMM) was used to evaluate the hydrologic effectiveness at a watershed scale of five LID technologies (vegetated swales, bioretention cells, porous pavement, rain barrels and tree boxes) in an existing, typical urban watershed. As implementation focused on public transportation areas, hydrologic effectiveness of runoff reduction was assessed as a function of roadway length: …

Modeling Food Security, Energy, And Climate And Cultural Impacts Of A Process: The Case Study Of Shea Butter In Sub-Saharan Africa, Colleen Claire Naughton

USF Tampa Graduate Theses and Dissertations

Millions of people in the world, particularly women and people in sub-Saharan Africa, suffer from hunger and poverty. Three of the major 2015-2030 United Nation’s Sustainable Development Goals (SDGs) aim to eliminate hunger through food security and sustainable agriculture, eradicate poverty, and achieve gender equality through women’s empowerment. Shea trees and their associated fruit and butter can play a major role in each of these three SDGs for women and their families throughout sub-Saharan Africa. Shea trees are located over a wide expanse stretching more than 5,000 kilometers across over eighteen countries in sub-Saharan Africa. These trees produce fruit that …

Resource Recovery Through Halophyte Production In Marine Aquaponics: An Evaluation Of The Nutrient Cycling And The Environmental Sustainability Of Aquaponics, Suzanne Boxman

USF Tampa Graduate Theses and Dissertations

Aquaculture, the farming of aquatic animals and plants, is an important component of global food production, which supplies a nutritious protein source for millions of people. Interest in improving the sustainability of aquaculture has led to the development of aquaponics in which fish production is combined with plant production to create zero-discharge systems. A need for more fundamental science and engineering research on marine aquaculture and growing interest in production of halophytes motivated this novel research on marine aquaponics. One objective was to evaluate the growth and nutrient removal capacity of halophytes in marine aquaponics. Bench-scale studies were conducted to …

Ammonium Removal From High Strength Wastewater Using A Hybrid Ion Exchange Biological Process, Veronica Ester Aponte-Morales

USF Tampa Graduate Theses and Dissertations

Anaerobic digestion (AD) has been shown to be an effective technique for energy recovery and stabilization of livestock wastes, municipal sludges and industrial wastewaters. However, further treatment is required to remove nitrogen from AD effluents to avoid detriments to surface and ground waters. The high free ammonia (FA) concentrations present in AD effluents can inhibit nitrification processes in conventional biological nitrogen removal (BNR) systems. The overall goal of this research was to develop a process for removal of nitrogen from AD swine waste (ADSW) effluent. The proposed solution was to incorporate particulate chabazite, which has a high cation exchange capacity, …

Pathogen Removal In Natural Wastewater Treatment And Resource Recovery Systems: Solutions For Small Cities In An Urbanizing World, Matthew Eric Verbyla

USF Tampa Graduate Theses and Dissertations

Sanitation, renewable energy, and food security are among the most pressing global development needs of the century, especially for small cities with rapid population growth. Currently, 53% of the world’s population either lacks access to improved sanitation or discharges fecal waste to the environment without treatment. Furthermore, 80% of food consumed in developing regions is produced by 500 million small farms, and while many of them are still rain-fed, irrigated agriculture is increasing. The post-2015 Sustainable Development Goals, recently adopted by the United Nations, include targets to address the water-energy-food nexus. Wastewater reuse in agriculture can be an important solution …

Corrosion Of Steel In Submerged Concrete Structures, Michael Thomas Walsh

USF Tampa Graduate Theses and Dissertations

This investigation determined that severe corrosion of steel can occur in the submerged portions of reinforced concrete structures in marine environments. Field studies of decommissioned pilings from actual bridges revealed multiple instances of strong corrosion localization, showing appreciable local loss of steel cross-section. Quantitative understanding of the phenomenon and its causes was developed and articulated in the form of a predictive model. The predictive model output was consistent with both the corrosion rate estimates and the extent of corrosion localization observed in the field observations. The most likely explanation for the observed phenomena that emerged from the understanding and modeling …

Effect Of Mineral And Chemical Admixtures On Durability Of Cementitious Systems, Victor Tran

USF Tampa Graduate Theses and Dissertations

Mineral and chemical admixtures are used today in almost all concrete mixtures to improve concrete fresh and hardened properties, and to enhance concrete durability. In this study, four mineral and four chemical admixtures were investigated: namely, metakaolin (MK), silica fume (SF), Class F fly ash (FA), blast-furnace slag (BFS), two high-range water reducers (SP), water reducer/retarder (WRD), and air-entrainer (AEA). The objective of this study is to assess the effects of commonly used mineral and chemical admixtures on the durability of the cementitious system. Two durability issues were addressed in this study: the potential of the cementitious system to generate …

Evaluating Corrosion Resistance Of Reinforcing Steel In A Novel Green Concrete, Andrea Carolina Ramirez

USF Tampa Graduate Theses and Dissertations

Reinforced concrete structures are expected to have a long service life with minimal maintenance. Corrosion of reinforcing steel is a major factor in reducing concrete structure lifespan, as corrosion products occupy a larger volume than that of the consumed steel and generate tensile stresses that crack the concrete cover. Procedures to control corrosion in traditional concrete, which is made with Portland-cement (PC), have been well established. However, in recent years novel concrete materials based on alternatives to normally cured PC have been developed in response to global needs to reduce greenhouse gases emissions. In particular, a promising new cement has …

Evaluation Of Low-Cost Low Impact Development Practices In Southwest Florida For The Control Of Urban Runoff, Laura Kathren Rankin

USF Tampa Graduate Theses and Dissertations

Stormwater management is required due to development and alteration of the natural environment. It is heavily regulated in Florida and at the national level. Over the last two decades, Low Impact Development (LID) has been promoted as a sustainable and environmentally friendly method of controlling urban runoff. Case studies, provided in Chapter 2, show that LIDs can restore watershed hydrology by balancing the water budget. The difference in runoff between pre-development and post-development appears to increase with soil perviousness. However, the potential for mitigating the impacts of urbanization through runoff reduction is also greater for pervious, sandy soils that dominate …

Binding Of Nitrite In Concrete, Cement Mortar And Paste, Saad Alshehri

USF Tampa Graduate Theses and Dissertations

Calcium nitrite as a corrosion inhibitor is mainly used to protect steel reinforcement in concrete by reducing its corrosion rate. Hence the effectiveness of calcium nitrite depends on its availability as a free nitrite in the pore solution. The present research work aims to determine the concrete mixture component mostly responsible for nitrite binding in concrete. Firstly, the experimental program included testing of nitrite binding in cement paste. Secondly, the effect of adding the fine aggregate (mortar mix) on nitrite binding was assessed. Finally, the mix with coarse aggregate (concrete mix) was evaluated. In-situ leaching method was used to obtain …

Feasibility Of Cathodic Protection In Grouted Post Tensioned Tendons - Exploratory Model Calculations, Jacob Dharma Bumgardner

USF Tampa Graduate Theses and Dissertations

Recent corrosion related failures of grouted post tensioned tendons, even after the introduction of improved grouts, have led to renewed interest in supplemental or backup means of corrosion control for these systems. A finite element model is presented to explore feasibility of impressed current cathodic protection of strand in grouted tendons. The model examines polarization evolution as function of service time and includes consideration of anode placement and size, grout porosity, pore water alkalinity, electrochemical species diffusivity and applied voltage on the polarization efficacy and durability of such a system. The exploratory model projections suggested that, within the context of …

Consumer Perception And Anticipated Adoption Of Autonomous Vehicle Technology: Results From Multi-Population Surveys, Nikhil Menon

USF Tampa Graduate Theses and Dissertations

Emerging automotive and transportation technologies, such as autonomous vehicles (AVs) have created revolutionary possibilities in the way we might travel in the future. Major car manufacturers and technology giants have demonstrated significant progress in advancing and testing AV technologies in real-life traffic conditions.

Results from multi-population surveys indicate that despite enjoying moderate familiarity with AVs, more than 40% of the respondents were likely to use them when they become available. Simply looking at the demographic differences without paying any regard to the perceptions might suggest that the demographic differences are the primary causal factors behind the differences observed in the …

Kelvin Probe Electrode For Field Detection Of Corrosion Of Steel In Concrete, Leonidas Philip Emmenegger

USF Tampa Graduate Theses and Dissertations

While the Kelvin Probe (KP) has been used in a variety of surface scanning applications, the use of the KP in reinforced concrete structures to detect corrosion has been pioneered by previous work performed at the University of South Florida. However, in that work, the scale and construction of the probes was not suited to use in the field. This is primarily attributable to the small operating disk-to-concrete gap which would make the probe unable to accommodate road conditions, such as irregularities in the grading of the road, and local pitting of the surface. Therefore, it was important to investigate …

Prediction Of The Optimum Binder Content Of Open-Graded Friction Course Mixtures Using Digital Image Processing, Yolibeth Mejias De Pernia

USF Tampa Graduate Theses and Dissertations

Florida Department of Transportation (FDOT) has been using Open Graded Friction Course (OGFC) mixture to improve skid resistance of asphalt pavements under wet weather. The OGFC mixture design strongly depends on the Optimum Binder Content (OBC) which represents if the mixture has sufficient bonding between the aggregate and asphalt binder. At present, the FDOT designs OGFC mixtures using a pie plate visual draindown method (FM 5-588). In this method, the OBC is determined based on visual inspection of the asphalt binder draindown (ABD) configuration of three OGFC samples placed on pie plates with pre-determined trial asphalt binder contents (AC). The …