Digital Commons Network^™

Multi-Objective Optimization Of A Ridesharing System Performance, Mohammad Nasr Azadani

Graduate Theses, Dissertations, and Problem Reports

Ridesharing is a shared vehicle service with the potential to meet the growing travel demand due to population increase, economic growth, and shortage in transportation infrastructure capacity. Compared to the current system of predominantly using personal vehicles, ridesharing services reduce the number of vehicles while providing mobility services to the same number of people with no additional investment in the transportation infrastructure. One of the big challenges in implementing ridesharing services is matching drivers and riders. Conflicts between matching-objectives to comply with the interests of diverse stakeholders influence the efficiency of ridesharing in a transportation system. This study investigates the …

Effect Of Binder Modification And Aggregate Size On Modulus And Fatigue Of Asphalt Concrete, Elizabeth Bashiti

Graduate Theses, Dissertations, and Problem Reports

Asphalt concrete is one of the main ingredients used in the paving of roadways across the globe. These roadways have been deteriorating from overuse, under design, and a lack of understanding of the engineering properties. In the asphalt community, it is agreed upon that polymer modifiers and aggregate size have comparable impacts on the performance of a pavement, such as, low creep at high temperatures, high ductility at low temperatures, high toughness, resistance to moisture and temperature, high cohesive and adhesive strength. With all of these advantages, it has been often assumed that polymer modifiers extend/improve the expected life of …

Doping With Rare Earth Elements And Resultant Nano-Inclusions On The Electrical And Thermal Properties Of The Mis-Fit Layered Thermoelectric Oxide, Geoffroy Gauneau

Graduate Theses, Dissertations, and Problem Reports

Thermoelectric generators produce electricity by directly converting temperature differences into electrical energy through Seebeck effect. Thermoelectric generators possess many unique features, such as having no moving part and being very reliable with a relatively long lifespan once built. They are solid-state waste heat harvesters. With various waste heat available throughout many industries, thermoelectric generators could offer economically competitive renewable energy. The current state of the art thermoelectric materials includes materials with relatively toxic elements and must work under vacuum, making them quite expensive to produce. Among the various thermoelectric materials, ceramic oxides have been proved to be more chemically stable …

Dynamic Study Of Mo/Zsm-5 Catalyst For Ch4 Dehydroadomation, Hadi Yahya Almusawa

Graduate Theses, Dissertations, and Problem Reports

Methane dehydroaromatization (CH₄-MDA) is a highly promising venture for natural gas utilization/exploitation, i.e., direct conversion of methane (CH₄) to liquid aromatics (benzene) and hydrogen. This process is a catalytic reaction and therefore, is subject to all the advantages and constraints of catalysis. This study discussed the structure and reactivity of Mo/ZSM-5 zeolite catalysts and their effect on the active conversion of methane to valuable aromatic products such as benzene: 1) The preparation and characterization of Mo/ZSM-5, which are crucial steps in any catalytic reaction process since a better performing catalyst consequently leads to better outcomes; 2) …

Development Of An Activity-Based Windowing Approach To Evaluate Real-World Nox Emissions From Modern Medium And Heavy-Duty Diesel Trucks, Rasik Pondicherry

Graduate Theses, Dissertations, and Problem Reports

The introduction of in-use emissions regulations by the United States Environmental Protection Agency (U.S.EPA) requires medium-duty (MD) and heavy-duty (HD) engine manufacturers to demonstrate emissions compliance during in-fleet operation. In the United States (U.S.), the Not-to-Exceed (NTE) method is used to evaluate real-world emissions compliance from on-highway MD and HD trucks. Regulatory agencies, engine manufacturers and research entities have identified that the NTE method incorporates numerous exclusions and evaluates emissions compliance only under selective operating conditions that are favorable for the selective catalytic reduction (SCR) system to reduce oxides of nitrogen (NOx) emissions efficiently. Such operation is typically encountered only …

Scaling-Based Robust Predictions Of Periodic Stream Water Quality Variables Across The Contiguous U.S., Mohammad Abu Zafer Siddik

Graduate Theses, Dissertations, and Problem Reports

Stream water quality is at the core of the biological and ecological health of streams and rivers. Subject to the environmental variation and in-stream metabolic activities, key water quality indicators such as dissolved oxygen (DO), water temperature (Tw), and chlorophyll a (Chl a, an indicator of primary productivity) typically follow a concave-shaped diurnal cycle. Variation and changes in climatic drivers (e.g., solar radiation, air temperature, and pressure), land uses, and hydrologic variables lead to a high spatiotemporal variability in stream water quality. The spatiotemporal variation challenges the development of robust models for predictions across large scales (e.g., county, state, country), …

Review Of Modern Nondestructive Testing Techniques For Civil Infrastructure, Shabnam Khanal

Graduate Theses, Dissertations, and Problem Reports

The repair and maintenance of aging infrastructures, in the United States alone, are estimated to have backlogs of trillions of dollars. This has posed widespread concerns about the existing and proposed infrastructures to adequately sustain the quality of life in the near future. Efficient and cost-effective approaches, such as nondestructive testing (NDT), are therefore required to better shape our future. Various NDT techniques have been developed over the past two decades with cutting-edge advances towards investigation and condition assessment of civil infrastructures. While the performance of NDT techniques has reached unparalleled heights, limitations remain. On one side, are the instrument …

Integrated Techno-Economic And Life Cycle Analyses Of Biomass Utilization For Value-Added Bioproducts In The Northeastern United States, Yuxi Wang

Graduate Theses, Dissertations, and Problem Reports

A multi-stage spatial analysis was first conducted to select locations for lignocellulosic biomass-based bioproduct facility, using Geographical Information System (GIS) spatial analysis, multi-criteria analysis ranking algorithm, and social-economic assessment. A case study was developed to determine locations for lignocellulosic biorefineries using feedstocks including forest residue biomass and three energy crops for 13 states in the northeastern United States. In the entire study area, 11.1% of the counties are high-suitable, 48.8% are medium-suitable for biorefinery siting locations. A non-parametric analysis of cross-group surveys showed that preferences on biorefinery siting are homogeneous for experts in academia and industry groups, but people in …

Monotonic Response Of Rc Exterior Beam-Column Joints Reinforced With Filler-Modules And Frp Composite Wraps/Gussets, Praveen Kumar Reddy Majjigapu

Graduate Theses, Dissertations, and Problem Reports

A review of post-earthquake reconnaissance studies revealed that reinforced concrete (RC) structures, designed and built before the development of Uniform Building Code (UBC) seismic design guidelines in 1976, have suffered complete collapse or severe damages due to the brittle failure of exterior beam-column joints. Over the past 50 years, several studies were conducted to strengthen exterior joints of in-service structures, with limited emphasis on developing simple, economic and durable repair strategies to improve energy absorption through large inelastic joint deformations. Even less emphasis was devoted to developing repair procedures that minimize stress-concentrations at joint corners and enhancing the strength, ductility, …

Fully Compressible Hydrodynamic Simulation Of Non-Equidiffusive Premixed Flames Propagation In Channels, Olatunde A. Abidakun

Graduate Theses, Dissertations, and Problem Reports

Premixed combustion remains of fundamental interest in energy generation and propulsion systems as well as in implementation of safety measures for residential and industrial accidental fire explosions. While the fast pace and complex nature of the combustion process has previously necessitated the analytical and computational studies to employ the simplifying assumption of equidiffusivity, when the Lewis number defined as the thermal-to-mass diffusivities ratio is unity , the ongoing advancements in technology and the requirements for efficiently operating combustors over a wide range of conditions make the combustion process more non-equdiffusive ( ) than ever. The impact of non-equidiffusivity on the …

Comparative Study Of Model-Based And Learning-Based Disparity Map Fusion Methods, Douglas E. Kerr Jr.

Graduate Theses, Dissertations, and Problem Reports

Creating an accurate depth map has several, valuable applications including augmented/virtual reality, autonomous navigation, indoor/outdoor mapping, object segmentation, and aerial topography. Current hardware solutions for precise 3D scanning are relatively expensive. To combat hardware costs, software alternatives based on stereoscopic images have previously been proposed. However, software solutions are less accurate than hardware solutions, such as laser scanning, and are subject to a variety of irregularities. Notably, disparity maps generated from stereo images typically fall short in cases of occlusion, near object boundaries, and on repetitive texture regions or texture-less regions. Several post-processing methods are examined in an effort to …

Assessment Of Heat Stress For Outdoor Work Conditions In Saudi Arabia, Jamal Alanazi

Graduate Theses, Dissertations, and Problem Reports

Outdoor workers have an increased risk of heat stress in Saudi Arabia since it is one of the hottest places in the Middle East. Recently, the government decided to limit outdoor work hours during the months of June, July, and August every year, and banned working under the direct sunlight from 12:00 to 03:00 p.m., although outdoor workers in the petroleum, natural gas, or emergency maintenance work industries are exempt from this prohibition. Traditionally, the efforts by safety and health professionals to mitigate work-related heat injury has been directed toward the assessment of environmental heat stress (e.g., wet-bulb globe temperature), …

Assess The Performance Against Ets And Pm1 And Evaluate The Users’ Experiences Of Comfort Of Nasal Filters, Ibrahim Almuhaidib

Graduate Theses, Dissertations, and Problem Reports

Many cities around the world experience severe air pollution. According to the World Health Organization (WHO), 7 million people die annually from exposure to small airborne Particulate Matter (PM) that is found in atmospheric pollution. Particulate matter in atmospheric pollution is one of six classifications of common air pollutants and is typically referred to as PM₁ and PM_2.5. Particulates designated as PM₁ and PM_2.5 refer to particles having aerodynamic diameters of 1 or 2.5 micrometer (µm), respectively. These size ranges of particles are the most commonly found in air pollution. It is hard to differentiate …

Transit Agencies Performance Assessment And Implications, Parisa Hajibabaee

Graduate Theses, Dissertations, and Problem Reports

Although most transit systems operate in small urban and rural areas in the United States, these systems have rarely received the same attention as their urban counterparts, both in terms of ensuring the efficiency and effectiveness of their operations and understanding the factors that affect their performance. This thesis's main goals are to assess the performance of rural and small urban public transit agencies and help them evaluate adopting a ridehailing program, thereby improving their performance. We applied operations research and decision-making tools to two public transit projects in small urban and rural areas. The first project focuses on three …

Interoperability Of Ip-Based Cameras, Faythe C. Maston

Graduate Theses, Dissertations, and Problem Reports

In this day and age of advancing technology and increasing crime, more and more citizens are investing in technology to increase their personal security. One such technology is the use of home-based IP security systems. These systems are comprised of one or more IP-based security cameras with owners preferring to have a way to view all camera feeds at once. Since not all security cameras are made to interact with each other, it is necessary to find a program that allows a user to view all security cameras at once, regardless of what brand of cameras they use. After researching, …

The Influence Of Spatial Variance On Rock Strength And Mechanism Of Failure, Danqing Gao

Graduate Theses, Dissertations, and Problem Reports

The heterogeneity in the rock formation affects both rock behavior and the strength. The effect of heterogeneity is observed both at the laboratory scale and at the rockmass level. The mechanical properties of intact rock vary considerably at laboratory scale and often an average value is used for design purposes. Similarly, the values are arbitrarily scaled when used at rockmass level. In underground coal mines, the effect of variability of properties is often observed with the erratic roof failure events that occur throughout the mine. The approach often was to use the deterministic values from limited site data to estimate …

Capital Equipment Upgrade Strategy In The Context Of Servitization, Muztoba Ahmad Khan

Graduate Theses, Dissertations, and Problem Reports

Building on manufacturing servitization and Product-Service Systems (PSS) business models, the midlife equipment upgrade services introduce promising alternative to traditional equipment replacement, which is often capital intensive and time consuming. Midlife upgrade describes the process of improving the performance of and adding new functional capabilities into equipment during their active usage period by embedding technological innovation while satisfying evolving customers’ preferences over time. This strategy, however, has thus far been discussed primarily from a conceptual perspective in literature, and the state of the art lacks empirical evidence regarding the potential and outcome of successful midlife upgrades. Additionally, explorative studies report …

An Examination To Pathways Powering Car Using Clean Energy, Marina Miranda

Graduate Theses, Dissertations, and Problem Reports

Traditional vehicles powered by internal combustion engines contribute significantly to increasing emissions of greenhouses gasses (GHG). There has been increasing interest in powering vehicles using green energy include using electricity produced by wind turbine and solar panel. The green electricity can be used to directly charge the Battery Electric Vehicles (BEV), or producing hydrogen as fuel for Fuel Cell Electric Vehicles (FCEV) by converting electrical energy to hydrogen (H₂) through water electrolysis. The low energy density H₂ produced can be stored on board as either compressed H₂ or liquefied H₂.

This research examines the …

Metaheuristics For The Generalized Quadratic Assignment Problem, Roseline Mostafa

Graduate Theses, Dissertations, and Problem Reports

The generalized quadratic assignment problem (GQAP) is the task of assigning a set of facilities to a set of locations such that the sum of the assignment and transportation costs is minimized. The facilities may have different space requirements, and the locations may have varying space capacities. Also, multiple facilities may be assigned to each location such that space capacity is not exceeded. In this research, an application of the GQAP is presented for assigning a set of machines to a set of locations on the plant floor. Two meta-heuristics are proposed for solving the GQAP: tabu search (TS) and …

Evaluation Of Process And Economic Feasibility Of Implementing A Topping Cycle Cogeneration System, Unique Karki

Graduate Theses, Dissertations, and Problem Reports

Industrial applications that require steam for their end-uses generally utilize steam boilers that are at higher size than what is typically required. Similarly, gas turbine-based power plants corroborate the gas turbine system and eventually relieve the exhaust into the atmosphere. These facilities include food, paper, chemicals, refining, and primary metal manufacturing industries. This research focuses on the scope of a topping cycle combined heat and power (CHP) system by pushing the load on the boiler to a higher limit, or a gas turbine operation in place of a boiler system for a topping cycle CHP and its economic feasibility by …

Review Of Established And Emergent Methods For The Production Of C4 Olefins, James Matthew Koval

Graduate Theses, Dissertations, and Problem Reports

Current production of C₄ olefins is dominated by naphtha cracking and butane dehydrogenation, but significant research interest is developing in alternate feedstocks due to an abundance of inexpensive natural gas and bioethanol. The current C₄ olefin production methods are costly, make use of already-depleted petroleum resources, and are often hazardous to workers, which forms the impetus for investigation into alternative methods and assessment of their viability as a future means of olefin production. Methods of natural gas conversion to higher order hydrocarbons are discussed, including Fischer-Tropsch synthesis and oxidative methane coupling, each of which could form the first …

Parametric Optimization Of Visible Wavelength Gold Lattice Geometries For Improved Plasmon-Enhanced Fluorescence Spectroscopy, Casey A. Norville

Graduate Theses, Dissertations, and Problem Reports

The exploitation of spectro-plasmonics will allow for innovations in optical instrumentation development and the realization of more efficient optical biodetection components. Biosensors have been shown to improve the overall quality of life through real-time detection of various antibody-antigen reactions, biomarkers, infectious diseases, pathogens, toxins, viruses, etc. has led to increased interest in the research and development of these devices. Further advancements in modern biosensor development will be realized through novel electrochemical, electromechanical, bioelectrical, and/or optical transduction methods aimed at reducing the size, cost, and limit of detection (LOD) of these sensor systems. One such method of optical transduction involves the …

Modulation Of Semiconductor Photoconversion With Surface Modification And Plasmon, Joeseph Martin Bright

Graduate Theses, Dissertations, and Problem Reports

Semiconductor devices are the basis of modern technology. Semiconductor-based photoconversion devices that convert light into electrical signals have shown potential for light energy harvesting and conversion, environmental remediation, and sensors for detection of light, chemicals, and biological substances. Despite this potential for use in many applications, semiconductor photoconversion devices need further improvement in the photoconversion performance. This photoconversion improvement may be manifested as increased photoconversion efficiencies for light harvesting devices for power generation such as photovoltaics and photoelectrochemical (PEC) cells or improved photoconversion modulation to increase the sensitivity of semiconductor photoconversion-based sensors. In addition, alternative semiconductor materials to semiconductors that …

Investigation Of Particle Measurement In Different Dilution Ratios With Gasoline Direct Injection And Port Fuel Injection, John Adam Phillips

Graduate Theses, Dissertations, and Problem Reports

Ambient air quality has been a concern in the United States since the mid-1900’s, forcing legislations like the Air Pollution Control Act and Clean Air Act necessary to bring focus on air pollution and quality. The Environmental Protection Agency (EPA) continues to update the requirements for more efficient vehicles and emissions sampling methods. Today the EPA has implemented regulations on modern spark ignited engines without any major focus on the type of injection technologies being used. While particle matter (PM) is a requirement to measure for a vehicle certification, more research should focus on the particle number (PN) measurements that …

Programming Of Floating-Gate Transistors For Nonvolatile Analog Memory Array, Haifa Abulaiha

Graduate Theses, Dissertations, and Problem Reports

Since they were introduced, floating-gate (FG) transistors have been used as non-volatile digital memory. Recent research has shown that floating-gate transistors can be successfully used as analog memory, specifically as programmable voltage and current sources. However, their proliferation has been limited due to the complex programming procedure and the complex testing equipment. Analog applications such as field-programmable analog arrays (FPAAs) require hundreds to thousands of floating-gate transistors on a single chip which makes the programming process even more complicated and very challenging. Therefore, a simplified, compact, and low-power scheme to program FGs are necessary. This work presents an improved version …

Process Development Of Shale Gas Assisted Lignin And Biomass Reforming Through Novel Reaction Pathway And Catalyst Design To Produce Hydrogen Rich Syngas For Fuels And Value Added Chemicals, Amoolya D. Lalsare

Graduate Theses, Dissertations, and Problem Reports

Novel biomass reforming strategy through synergistic co-processing with flare gas (methane and carbon dioxide) was developed at West Virginia University. Hardwood biomass comprised of lignin, hemicellulose, and cellulose is abundant in the US and potentially a sustainable source of hydrogen through extensive reforming and gasification. Ever-increasing shale gas production in the US occasionally leads to flaring owing to stranded production across the US. Achieving biomass co-processing with natural gas about to be flared in such stranded shale plays is the underlying motivation here. A novel reaction pathway was discovered wherein methane and carbon dioxide assisted reforming of biomass could be …

Assessment Of Unmanned Aerial Systems And Lidar For The Utility Vegetation Management Of Electrical Distribution Rights-Of-Ways, Matthew R. Walker

Graduate Theses, Dissertations, and Problem Reports

Utility Vegetation Management (UVM) is often the largest maintenance expense for many utilities. However, with advances in Unmanned Aerial Systems (UAS; or more commonly, “drones”) and lidar technologies, vegetation managers may be able to more rapidly and accurately identify vegetation threats to critical infrastructures. The goal of this study was to assess the utility of Geodetics’ UAS-lidar system for vegetation threat assessment for 1.6 km of a distribution electric circuit. We investigated factors which contribute to accurate tree crown detection and segmentation of trees from within an UAS-lidar derived point cloud, and the factors which contribute to accurate tree risk …

Investigation Of Phonon Polaritons In An Hbn Gan Heterostructure, Catherine G. O'Hearn

Graduate Theses, Dissertations, and Problem Reports

There have been many great advances in the generation and manipulation of optics in the visible and near infrared (IR) range over the past decade. This is largely due to plasmonic enhancement, which has led to new technology in biosensing and molecule detection, solid-state lighting, and solar energy harvesting. The field of plasmonics uses quanta of plasma oscillations, plasmons, formed from the interaction between electromagnetic radiation and free electrons to enhance optical near field magnitudes. However, there is still a large region of the electromagnetic spectrum, covering the mid-infrared (MIR) and terahertz (THz) regions, ranging from 3 μm to 1 …

Evaluation Of Fitts’ Throughput As A Possible Performance Measure For Manual Assembly Tasks, Pradyumna Bettagere Jagadish

Graduate Theses, Dissertations, and Problem Reports

Assembly lines are the backbone of the manufacturing sector. Workers at the assembly lines are expected to perform fast pace hand-arm exertions with precision and accuracy. To protect the workers from injuries, OSHA mandates the use of personal protective equipment (PPE) including gloves. Certain assembly operations require the use of special gloves. Some of these gloves can inhibit hand performance, further increasing the task difficulty. The Index of Difficulty (ID) is a metric measured in ‘bits’ quantifies task difficulty through the quotient of target width and target motion, i.e., distance travelled. The time required to complete the target motion is …

Design And Optimization Of Dynamic System For A One-Kw Free Piston Linear Engine Alternator-Gensets Program, Nima Zamani Meymian

Graduate Theses, Dissertations, and Problem Reports

In power/energy systems, free-piston linear machines are referred to as a mechanism where the constrained crank motion is eliminated and replaced with free reciprocating piston motion. Depending on the application, the piston motion can be converted into other types of energy and includes compressed air/fluid, electricity, and high temperature/pressure gas. A research group at West Virginia University developed a free-piston linear engine alternator (LEA) in 1998 and have achieved significant accomplishment in the performance enhancement of the LEAs to date. The present LEA design incorporates flexure springs as energy restoration components and as bearing supports. The advantages of using flexure …