Civil and Environmental Engineering Commons^™

Safety Assessment And Risk Estimation For Unmanned Aerial Vehicles Operating In National Airspace System, Xuejun Zhang, Yang Liu, Yu Zhang, Xiangmin Guan, Daniel Delahaye, Li Tang

Civil and Environmental Engineering Faculty Publications

This paper proposes an effective approach for modelling and assessing the risks associated with unmanned aerial vehicles (UAVs) integrated into national airspace system (NAS). Two critical hazards with UAV operations are considered and analyzed, which are ground impacts and midair collisions. Threats to fatalities that result from the two hazards are the focus in the proposed method. In order to realize ground impact assessment, a multifactor risk model is designed by calculating system reliability required to meet a target level of safety for different UAV categories. Both fixed-wing and rotary-wing UAVs are taken into account under a real scenario that …

Oil Droplet Transport Under Non-Breaking Waves: An Eulerian Rans Approach Combined With A Lagrangian Particle Dispersion Model, Roozbeh Golshan, Michel C. Boufadel, Victor A. Rodriguez, Xiaolong Geng, Feng Gao, Thomas King, Brian Robinson, Andres E. Tejada-Martinez

Civil and Environmental Engineering Faculty Publications

Oil droplet transport under a non-breaking deep water wave field is investigated herein using Computational Fluid dynamics (CFD). The Reynolds-averaged Navier–Stokes (RANS) equations were solved to simulate regular waves in the absence of wind stress, and the resulting water velocities agreed with Stokes theory for waves. The RANS velocity field was then used to predict the transport of buoyant particles representing oil droplets under the effect of non-locally generated turbulence. The RANS eddy viscosity exhibited an increase with depth until reaching a maximum at approximately a wave height below the mean water level. This was followed by a gradual decrease …

A Systems Analysis Of Factors Influencing Household Solar Pv Adoption In Santiago, Chile, Jeffrey Walters, Jessica Kaminsky, Lawrence Gottschamer

Civil and Environmental Engineering Faculty Publications

Societal uptake of household solar photovoltaic (PV) technology is the result of a complex and interdependent array of technical, social, political and economic factors. This novel study employs a systems lens to examine both technical and non-technical barriers to renewables, with a focus on interactions that are empirically influential on PV uptake. Using local solar expert stakeholder input into a participatory systems approach, this study provides a structural analysis of factors influencing household solar adoption. The approach is applied and assessed for household solar PV systems in Santiago, Chile, to gain insight into the interconnected factors driving technology adoption. Barriers …

Lies, Damned Lies, Avs, Shared Mobility, And Urban Transit Futures, Graham Currie

Journal of Public Transportation

It seems to me there is a gigantic lot of nonsense discussed about the future of transport and the future of public transport in particular. As a researcher in the field, I find my emotions boiling over. I get angry at blanket statements telling us public transport has no future and it seems to me much of what is talked about regarding transport futures flies in the face of facts and a long history of what knowledge has gleaned about the human condition, economics, cities, and travel. My hope is that readers will see prevailing discourse differently as a result …

Does The Future Of Mobility Depend On Public Transportation?, Kari Watkins

Journal of Public Transportation

We’ve all seen the headlines. “Will self-driving cars, taxis make mass transit obsolete?” (Davidson 2017) and “What happens if Uber or Lyft outcompetes public transit?” (Sen 2017) or even “Department Of Transportation Says The Future Of Transit Looks Pretty Bleak” (Griggs 2015). We are entering the next great revolution in how people move about in cities. But does the future of transportation mean the end of transit?

Improved Mobility Through Blurred Lines, Carol Schweiger

Journal of Public Transportation

No abstract provided.

Better Integrating Travel Choices Into Future Urban Mobility Systems: The Day The Highways Stood Still, Eric Schreffler

Journal of Public Transportation

No abstract provided.

Not If, But When: Autonomous Driving And The Future Of Transit, Jerome M. Lutin

Journal of Public Transportation

This paper discusses the implications of autonomous vehicle technology on auto use and travel behavior, and the resulting impacts on public transportation. The paper goes on to explore how autonomous driving technology can make more efficient use of bus transportation and improve service to disabled individuals. The paper concludes with recommendations for transit agencies to engage with government and suppliers of autonomous vehicles to promote research, development, and policies that will allow the industry to reap the benefits of this revolutionary and disruptive technology.

Reflections On The Future Of Public Transportation, Joel Volinski

Journal of Public Transportation

No abstract provided.

A Synthesis Of Mobile Ticketing Applications Used By Commuter Railroads In The United States, Jonathan Mesoraca, Candace Brakewood

Journal of Public Transportation

Since 2012, many major commuter railroads have deployed mobile ticketing applications (or “apps”) that allow passengers to pay fares directly using their smartphones. In light of this rapid technological change, this research aims to provide a synthesis of the current state of mobile ticketing in the United States. The 14 largest commuter railroads that have launched mobile ticketing apps are compared in four different areas: (1) the ticket validation process; (2) ticket types offered in the mobile app; (3) additional features in the app; and (4) the process for transferring to other modes using the app. The results reveal that …

Ex-Regular Users Of Public Transport: Their Reasons For Leaving And Returning, Paula Vicente, Elizabeth Reis

Journal of Public Transportation

This paper describes the characteristics of former regular users of public transport in the metropolitan area of Lisbon. It also examines why these people stopped using public transport and explores what would make them become regular users again. The empirical results revealed significant socio-demographic differences between current and ex-regular users, namely in relation to gender and social level. Differences were also found in travel characteristics, car ownership, and satisfaction with the transit service. The main reasons given by ex-regular users for no longer using public transport included changes in their lives (e.g., change in workplace/residence/ school or becoming unemployed) and …

Can Public Transportation Compete With Automated And Connected Cars?, Ralph Buehler

Journal of Public Transportation

Over the next 30 years, technological innovation will make automobile travel more convenient. Automated and connected vehicles will perform an increasing number of driving tasks without human input and will lure customers away from traditional public transportation. This paper first explores key characteristics of public transportation demand in the United States today--based on an international comparison with other Western countries. Next, the paper provides potential pathways on how public transportation agencies and local governments in the United States could respond to the emergence of automated and connected vehicles. The paper argues that space efficiency in urbanized areas and the rush …

Future Of Rural Transit, Jill Hough, Ali Rahim Taleqani

Journal of Public Transportation

This paper provides a contemplative description of the future of rural public transportation. It considers emerging technologies along with their long-term implications and corresponding impacts on rural communities. The authors used their collective knowledge to identify key drivers of change in rural areas. As a result, the authors expect the future definition of rural areas to change and a new geographical classification to emerge. This classification is a continuum of population density gradient from highly populated urban areas to sparsely populated areas. The paper also suggests that automated vehicles and hologram telecommuting could dominate the U.S. transportation industry, even in …

Just Around The Corner: The Future Of U.S. Public Transportation, Steven E. Polzin

Journal of Public Transportation

No abstract provided.

Is It Time For A Public Transit Renaissance?: Navigating Travel Behavior, Technology, And Business Model Shifts In A Brave New World, Susan Shaheen, Adam Cohen

Journal of Public Transportation

Travel behavior is undergoing a period of significant change in the United States. In 2016, public transit ridership fell in almost all major U.S. metropolitan regions. While Americans are still heavily dependent on the personal automobile for mobility, technological and societal changes are transforming how mobility is accomplished. This paper reviews the convergence of five trends leading to fundamental changes in public transportation: (1) changing generational behavior toward suburbanization and automobility; (2) new attitudes toward information communications technology; (3) shifting attitudes toward sharing and mobility on demand; (4) innovative alternatives to work and non-work travel; and (5) an increasing number …

Transit In The 2000s: Where Does It Stand And Where Is It Headed?, Michael Manville, Brian D. Taylor, Evelyn Blumenberg

Journal of Public Transportation

U.S. public transit has experienced something of a renaissance in the 2000s, with per capita service levels increasing nationwide and public investment growing even faster—particularly expenditures on rail transit. Despite this expansion, overall transit patronage has been relatively flat, and has declined significantly since 2014. What is behind these trends, and what do they portend for the future of transit? In this paper we consider three challenges shaping transit today and in the years ahead: (1) the asymmetry of transit supply and use make it especially vulnerable to changes and disruptions; (2) many of the factors that determine transit ridership, …

To Predict With Confidence, Plan For Freedom, Jarrett Walker

Journal of Public Transportation

No abstract provided.

Analysis On The Influence Factors Of Accident Severity: Evidence From Urban River-Crossing Tunnels In Shanghai Of China, Wan He, Zhuoye Zhang, Linjun Lu, Zhenyu Wang

CUTR Faculty Journal Publications

To analyze various factors influencing the accident severity of urban river-crossing tunnels, 12 influence factors were selected according to the three traffic elements of vehicle, road, and environment, including accident-involved vehicle type, tunnel length, tunnel speed limit, accident occurrence time, and weather. These factors were based on the historical data of 14 urban river-crossing tunnels in Shanghai. A binary logistic regression model was also utilized to identify significant influence factors and analyze the influence degrees of their accident severity. Significance analysis reveals that accident occurrence place, accident-involved vehicle type, tunnel speed limit, number of vehicles involved, and accident type are …

Construction Effects On The Side Shear Of Drilled Shafts, Lucas Caliari De Lima

USF Tampa Graduate Theses and Dissertations

Design methods for side shear of drilled shafts, including the resistance factors that should be applied, do not account for any specific construction procedure. Instead, design often relies on analysis of case studies which include all construction methods used in each geomaterial type (e.g. clays, sands and rocks), or on parametric analysis. Nonetheless, literature suggests that different construction procedures result in varying side shear.

This research investigated 2 types of construction: (1) slurry stabilization in sandy soils using bentonite and polymer products that are commonly used on the field, with exposure times from near 0h to 96h, and (2) temporary …

Understanding The Linkages Between Urban Transportation Design And Population Exposure To Traffic-Related Air Pollution: Application Of An Integrated Transportation And Air Pollution Modeling Framework To Tampa, Fl, Sashikanth Gurram

USF Tampa Graduate Theses and Dissertations

Rapid and unplanned urbanization has ushered in a variety of public health challenges, including exposure to traffic pollution and greater dependence on automobiles. Moreover, vulnerable population groups often bear the brunt of negative outcomes and are subject to disproportionate exposure and health effects. This makes it imperative for urban transportation engineers, land use planners, and public health professionals to work synergistically to understand both the relationship between urban design and population exposure to traffic pollution, and its social distribution. Researchers have started to pay close attention to this connection, mainly by conducting observational studies on the relationship between transportation, urban …

Dns And Les Of Scalar Transfer Across An Air-Water Interface During Inception And Growth Of Langmuir Circulation, Amine Hafsi

USF Tampa Graduate Theses and Dissertations

Direct numerical simulations (DNS) of an initially quiescent coupled air-water interface driven by an air flow with free stream speed of 5 m/s have been conducted. The DNS solves a scalar advection-diffusion equation for dissolved gas (or scalar) concentration in order to determine the impact of the water-side turbulence on scalar (mass) transfer from the air side to the water side and subsequent vertical transport in the water column. Two simulations are compared: one with a freely deforming interface and a second one with a flat interface. In the first simulation, the deforming interface evolves in the form of gravity-capillary …

The Control Of Water Contaminants Assisted By Natural Materials, Wen Zhao

USF Tampa Graduate Theses and Dissertations

Natural materials can be used to remove water contaminants by applying proper physical, chemical, and biological water treatment processes. This study involves using natural materials, as they are considered to be more environmentally benign and cost-effective than synthetic materials. This dissertation concentrates on monitoring five major water quality parameters—ammonia, fluoride, turbidity, pH, and fecal indicator bacteria (FIB) —in two major applications where clean water is needed. The focus is on meeting the water quality requirements for each contaminant. The overall objective of this study is to control the levels of ammonia in aquaculture wastewater, and adjust fluoride, turbidity, pH, and …

Water, Sanitation, And Citizenship: Perceptions Of Water Scarcity, Reuse, And Sustainability In Valparaiso De Goias, Brazil, Paola Andrea Gonzalez

USF Tampa Graduate Theses and Dissertations

Access to reliable water and sanitation are two important goals to improve livelihoods around the world. Providing access to improved and safe water resources that are equitable and appropriate to local needs is important to improve sustainability long-term. In addition, framing access to water and sanitation as basic human rights is often used as a rationale in developing new water, sanitation, and hygiene interventions in developing countries around the world. But not all countries consider access to safe water and sanitation as a human right. In the thesis, the politics of improving and investment in water access and sanitation provision …

Analysis Of Distresses In Asphalt Pavement Transitions On Bridge Approaches And Departures, Manvitha Rajalingola

USF Tampa Graduate Theses and Dissertations

Some highway agencies in the United States are experiencing frequent distresses in asphalt pavements on bridge approaches/departures. Commonly observed distresses include alligator cracking and rutting, which reduce roadway smoothness and safety. To lessen the distresses in pavements it is needed to investigate the extent and root causes of the problem. Based on Florida highway conditions, this research study mainly focused on1. Literature review and identification of the extent of the problem; 2. Collection of relevant pavement condition data and descriptive analysis; 3. Development of statistical models to determine factors influencing the distresses in asphalt pavements on bridge approaches/departures. To the …

Enhancement Of Two Passive Decentralized Biological Nitrogen Removal Systems, Justine L. Stocks

USF Tampa Graduate Theses and Dissertations

This research evaluates two different Biological Nitrogen Removal (BNR) systems for enhanced nitrogen removal in decentralized wastewater treatment. The first study evaluated the performance of Hybrid Adsorption and Biological Treatment Systems (HABiTS) at the pilot scale with and without stage 1 effluent recirculation. HABiTS is a system developed at the bench scale in our laboratory and was designed for enhanced BNR under transient loading conditions. It consists of two stages; an ion exchange (IX) onto clinoptilolite media coupled with biological nitrification in the aerobic nitrification stage 1 and a Tire-Sulfur Adsorption Denitrification (T-SHAD) system in the anoxic denitrification stage 2. …

How Transportation Network Companies Could Replace Public Transportation In The United States, Matthew L. Kessler

USF Tampa Graduate Theses and Dissertations

The quantity of cell phone applications or mobile apps have seen an upsurge at an exponential rate in under a decade. Many have been created for a variety of industries, including transportation. The advent and subsequent commercialized implementation of near-instant transport by a middleman-type of app is now known as a Transportation Network Company or TNC. Examples of the more renowned TNCs are Uber, Lyft and Sidecar.

In recent years, TNCs have cultivated a tremendous following, to the degree of taxicab desertion. Moreover, the massive success of TNCs led to expansion of its capacities into public transportation.

The TNC’s expeditious …

The Effect Of Chemical Composition Of Blast-Furnace Slag On Compressive Strength And Durability Properties Of Mortar Specimens, William J. Johnson

USF Tampa Graduate Theses and Dissertations

In an effort to make structures more sustainable and durable, supplementary cementitious materials are often used to replace cement. Ground granulated blast furnace slag, for instance, is an industrial by-product of iron refinement and is frequently used in concrete mixture design to not only reduce cost, but also increase later-age strength as well as durability. However, published literature indicates that slags with a high alumina content may have a detrimental effect when concrete is exposed to a sulfate environment. ASTM standard C989 does not suggest any information or guidelines regarding using slags with an alumina content between 11-18%. Therefore, the …

Sustainability Of Community-Managed Rural Water Supply Systems In Amazonas, Peru: Assessing Monitoring Tools And External Support Provision, Jacob E. Mangum

USF Tampa Graduate Theses and Dissertations

Globally, there is still a large number of people without access to safe drinking water; a known health risk. In rural areas of countries like Peru, when potable water systems are built the responsibility for maintaining these systems is given to volunteer water committees. Despite its prevalence as a management model, there is a consensus that community management alone cannot ensure sustainable water service. Therefore, the overall goal of this research is to assess the sustainability of community-managed water systems in rural areas of the department of Amazonas, Peru. Specifically, this research examines two mechanisms that have been shown to …

Towards Food Service Sustainability In Suburban Environments By Optimally Locating Shared Anaerobic Digester Units, Rebecca Loraamm, Joni Downs, Robert Alonso Bair, Daniel Yeh

Suburban Sustainability

Anaerobic digestion is an effective method for reducing food waste at the consumer level. Drawbacks associated with this strategy include high construction costs for multiple digester units and limited public awareness of the method’s commercial potential. Given the large scale problem of food waste, an approach establishing community partnerships between local businesses and primary schools is offered to combat the problem of food waste. Optimizing the placement of shared digester units enabling utilization by multiple stakeholders is the suggested mitigation method. This research explores application of the p-median problem to determine the set of optimal sites for shared anaerobic digester …

The Fate Of Fecal Indicator Bacteria In Passive Nitrogen Reduction Systems, Michelle B. Henderson

USF Tampa Graduate Theses and Dissertations

The sustainability of water resources is an international and national concern. With increased human activity, water distribution on a global, regional, and local scale has been negatively impacted. Managing water resources also includes managing wastewater. A promising solution to the issues of water scarcity and distribution in the environment is the reuse of wastewater. Wastewater is produced from various sources (domestic, industrial, and commercial); however, if this water is able to be reused closer to the source of generation it could positively impact water distribution. In the United States, approximately 25% of domestic wastewater is treated in onsite wastewater treatment …