Digital Commons Network^™

Multistage Stochastic Programming: Algorithms, Modelling And Applications, Murwan Siddig

All Dissertations

This dissertation comprises four different topics related to multistage stochastic programming (MSP) algorithms, modeling, and applications.

First, we extend the adaptive partition-based approach for solving two-stage stochastic programs with a fixed recourse matrix and a fixed cost vector to the MSP setting, where the stochastic process is assumed to be stage-wise independent. The proposed algorithms integrate the adaptive partition-based strategy with a popular approach for solving multistage stochastic programs, the stochastic dual dynamic programming (SDDP) algorithm, according to two main strategies. These two strategies are distinct from each other in the manner by which they refine the partitions during the …

Heavily Obscured Active Galactic Nuclei In The Nustar Era, Xiurui Zhao

All Dissertations

Active galactic nuclei (AGN) are among the brightest objects in the sky. The enormous intrinsic emission of the AGN is produced by the gas accreted onto the central supermassive black hole (SMBH). Most of the AGN intrinsic emission are obscured by the material in a toroidal structure (or the torus) in AGN. This obscuring torus has been resolved in recent observations. However, many of its properties are still unknown, e.g., the torus covering factor and the torus density. My dissertation is focused on studying the AGN torus properties in X-rays. Heavily obscured AGN (NH ≥10^{23} cm^{−2}) are the best sample …

Determinants Of Consumer Decisions In An Online Marketplace: The Decision-Making Process In The Home Improvement Service Domain, Amal Pradeep Ponathil

All Dissertations

Home improvement services industry are a multi-billion dollar industry with an ever increasing online presence as a result of advancements in technology. Such websites as Angie’s List, Thumbtack, and Home Advisor allow for information exchange between online consumers. Also known as Electronic Word of Mouth (eWOM), this information offers several advantages, for example quick dissemination and convenience; however, trust in such information is a key factor in consumer’s decision-making. With the increased use of eWOM in making decisions, it is important to investigate how consumers use the cues found on these websites, the research gap this dissertation addresses.Given the lack …

Plasmon Enhanced Gan Mems Photoacoustic Sensors, Digangana Khan

All Dissertations

This dissertation aims to repot the demonstration of strong enhancement in photoacoustic signal due to plasmonic absorption and highly sensitive detection of trace level analytes utilizing the plasmonic enhancement of photoacoustic signal using piezotransistive GaN microcantilevers. A pulsed 790 nm laser focused on the Au metallization of the piezotransistor resulted in a high amplification of photoacoustic signal compared to the non-metallized areas. Upon deposition of 5 nm Au layer, the photoacoustic signal increased significantly for both previously metallized and non-metallized areas, while 2 nm Ni deposition decreased the photoacoustic signal, confirming the role of Au nanostructures in facilitating plasmonic absorption. …

Biofilm Deterrence On Surfaces Exposed To Continuous Ultraviolet-C Radiation As A Tool For Mitigating Bacterial Pathogens: Developing A Biofilm-Uvc Intensity Response Model, Hamed Torkzadeh

All Dissertations

Biofilm growth on engineered surfaces poses a risk to public health and presents a challenge in several industries, such as the food industry, as biofilms harbor a wide range of microorganisms, including opportunistic respiratory pathogens. In the context of drinking water, conventional secondary disinfectants such as free chlorine and chloramines are not known to fully prevent biofilm formation at relevant concentrations necessitating the development of scalable, effective interventions. The issue of biofilms and their role as a host to a wide range of pathogenic microorganisms can be more effectively addressed at the point-of-dispensing. Unlike building-point-of-entry or point-of-use devices interventions, there …

New Strategies To Combat Fouling In Membrane-Based Water Treatment Applications, Anna Malakian

All Dissertations

The main challenge of pressure-driven membrane operations is fouling, which refers to materials build-up on a membrane surface that increases the mass-transfer resistance of the membrane and, ultimately, the operating cost associated with higher-pressure operation and chemical cleaning. One way to combat fouling is the physical modification of a membrane surface by adding patterns of structural features that disrupt foulant deposition. My dissertation research goal was to develop the basic science needed to design new fouling-resistant membranes by understanding what factors most influence how foulants interact with patterned membrane surfaces.After introducing the basic methods used for membrane modification, Chapter 1 …

Evaluating Pea (Pisum Sativum L.) For Nutritional Traits And Implications For Organic Agriculture And Biofortification, Sarah Powers

All Dissertations

Pea (Pisum sativum L.) is an important cool season food legume for sustainable food production and human nutrition due to its nitrogen fixation capabilities and nutrient-dense seed. However, phosphorus (P) can be a major limiting nutrient for pea production, as their nodules require additional amounts of P to perform and maintain nitrogen fixation activity, and for adequate biomass and yield. To determine if genetic variation exists in pea’s ability to take up and remobilize P from the soil, we conducted a greenhouse experiment to collect tissues at two developmental stages from plants grown under a normal and reduce P …

Gemcitabine-Loaded Microbubble System For Ultrasound Imaging And Therapy., Lauren J. Delaney, John R. Eisenbrey, David Brown, Jonathan R Brody, Masaya Jimbo, Brian E Oeffinger, Maria Stanczak, Flemming Forsberg, Ji-Bin Liu, Margaret A Wheatley

Department of Radiology Faculty Papers

Ultrasound imaging presents many positive attributes, including safety, real-time imaging, universal accessibility, and cost. However, inherent difficulties in discrimination between soft tissues and tumors prompted development of stabilized microbubble contrast agents. This presents the opportunity to develop agents in which drug is entrapped in the microbubble shell. We describe preparation and characterization of theranostic poly(lactide) (PLA) and pegylated PLA (PEG-PLA) shelled microbubbles that entrap gemcitabine, a commonly used drug for pancreatic cancer (PDAC). Entrapping 6 wt% gemcitabine did not significantly affect drug activity, microbubble morphology, or ultrasound contrast activity compared with unmodified microbubbles. In vitro microbubble concentrations yielding ≥ 500nM …

Aug2021, Robert Kelly

Robert Kelly Manuscripts

No abstract provided.

Effect Of Obesity On Walking To Running And Running To Walking Transitions, Salvador Baruch Alcorta Bautista

Theses and Dissertations

This work investigates human Walking to Running transition (WRT) and Running to Walking transition (RWT). The focus is to be able to identify the correct WRT and RWT phase jumps. This investigation uses experimental data from the VICON Motion Analysis System (MAS) and of the treadmill WRT and RWT trials. The musculoskeletal model consists of pelvis, femur, tibia, and foot. This investigation uses as reference the work reported in the literature by Diedricj and Warren.. For the calculations in this investigation Excel and Matlab are used to filter the data and calculate the relative phase jumps. This work reports the …

Biochar Applications To The Remediation Of Lead And Polychlorinated Biphenyl Contaminated Water, Victory Itua Igberase

Theses and Dissertations

This study investigated the performance of biochar materials as adsorbents to remove Pb and polychlorinated biphenyl (PCB) in aqueous solutions. Batch adsorption and column experiment packed with biochar and geomaterials (pumice) in 1:1 volume ratio was evaluated to address the efficacy of biochar in removing Pb while only batch adsorption was employed for PCB removal with biochar materials. Overall, PT biochars performed the best (42–53 mg g−1) followed by BE biochars (10–32 mg g−1) and AB biochars (17–27 mg g−1) while high temperature biochars were favored in terms of maximum Pb adsorption capacity. Column Pb breakthrough showed similar results, with …

Soil Chemistry Modification By Guinea Grass In Semi-Arid Soils: A Litter Mediated Positive Feedback, Vanessa Elizabeth Thomas

Theses and Dissertations

Nutrients are a key component of healthy soils. Their composition plays an important role in plant growth through nutrient cycling and directly influences the functioning of plant communities in both agricultural and natural ecosystems. Shifts in macronutrients such as phosphorus and nitrogen may be initiated by invasive growth as a driver for competition with native plants. The goal of this study is to explore the plant soil feedback in an exotic invasive plant, Guinea grass (Pancium maximum), an invasive bunch grass originally from Africa, across different habitat types in the Lower Rio Grande Valley (LRGV). To determine a positive plant …

Below-Deck: The Specialist Sailor In World War Ii, Gregory Falcon

War, Diplomacy, and Society (MA) Theses

U.S. Navy ships were made up of many unexpected jobs during World War II. Traditional war histories say little about sailors who rarely saw direct combat below active war decks but instead worked skilled jobs. Specialized sailors were often unseen as they worked below the waterline as, for example, electrician’s mates and boiler room firemen. These jobs were pivotal to keeping the ship running and allowed men to make use of their valuable time in the navy. This thesis argues that, although evolving naval culture led men to enter for various reasons, many entered to enhance their future career during …

Machinability Of Carbon Fiber Reinforced Polymer (Cfrp) Composites: Modeling And Optimization Using Taguchi Analysis And Multi-Objective Genetic Algorithm, S M Abdur Rob

Theses and Dissertations

Carbon Fiber Reinforced Polymer (CFRP) composites have been widely used in aerospace, automotive, nuclear, and biomedical industries due to their high strength to weight ratio, corrosion resistant durability and excellent thermo-mechanical properties in non-oxidative atmospheres. Machining of CFRP composites has always been a challenge for the manufacturers. In this study, turning operation has been performed on CFRP composites to investigate the effects of cutting parameters namely cutting speed, feed rate and depth of cut on the output characteristics including cutting force, surface roughness and tool wear using Taguchi Analysis. Regression Analysis has been used to develop mathematical model for cutting …

North Korean Cyber Attacks And Policy Responses: An Interdisciplinary Theoretical Framework, Jeeseon Hwang, Kyung-Shick Choi

International Journal of Cybersecurity Intelligence & Cybercrime

No abstract provided.

Effectiveness Of Softening Agents For Enhancing Properties Of Asphalt Mixes With High Rap Contents, Zahid Hossain, Ashraf Elsayed, Sumon Roy

Publications

A high percentage of reclaimed asphalt pavement (RAP) in new asphalt concrete can lead to developing premature failure of asphalt pavements due to fatigue or low-temperature cracking. The use of softening agents in asphalt binders can resolve these problems. The aim of this study is to evaluate the effectiveness of softening agents for enhancing the properties of asphalt mixes with high RAP contents. Two waste products, namely, waste cooking oil (WCO), and engine bottom oil (EBO) along with a commercially produced rejuvenator were investigated in this study. The following three types of Performance Grade (PG) binders, each collected from two …

Feasibility Assessment Of Warm Mix Asphalt In Arkansas, Zahid Hossain, Ashraf Elsayed, Mohammad Najmush Sakib Oyan

Publications

The future of Warm Mix Asphalt (WMA) technologies is promising in the U.S. However, the Arkansas Department of Transportation (ARDOT) does not have any specific guidelines to implement them in the field. This research aims to provide necessary baseline data for WMA as a proof of concept. In this study, three ARDOT approved Performance Grade (PG) binders namely PG 64-22, PG 70-22, and PG 76-22 were investigated. Each of these binders was obtained from two different sources. They were modified by varying doses of four selected additives: Sasobit®, Advera®, Evotherm®, and Rediset®. Additionally, four different types of aggregates (sandstone, limestone, …

Development Of Cost-Effective High-Modulus Asphalt Concrete (Hmac) Mixtures Using Crumb Rubber And Local Construction Materials In Louisiana, Momen R. Mousa, Marwa Hassan, Ibrahim A.I.E Elnaml

Publications

One of the emerging solutions to enhance the durability of asphalt pavements is the use of a French asphalt mix known as “High-Modulus Asphalt Concrete (HMAC).” This mix uses a hard asphalt binder, high binder content (about 6%), and low air voids content as compared to Superpave mixtures. The key objective of this study was to develop a cost-effective HMAC mixture using crumb rubber and local materials in Louisiana. To achieve this objective, four HMAC mixtures were prepared using two asphalt binders (PG 82-22 and PG 76-22 plus 10% crumb rubber) and two Reclaimed Asphalt Pavement (RAP) contents (20% and …

Evaluation Of Alternative Sources Of Supplementary Cementitious Materials (Scms) For Concrete Materials In Transportation Infrastructure, Gabriel A. Arce, Miladin Radovic, Zahid Hossain, Marwa Hassan, Sujata Subedi

Publications

Fly ash is the most utilized supplementary cementitious material (SCM) in the US. Nonetheless, rapid decline in coal-fired power generation threatens its supply. The objective of this study was to evaluate alternative SCMs for concrete transportation infrastructure in Region 6. SCMs investigated included reclaimed fly ash (RFA), reclaimed ground bottom ash (GBA), metakaolin (MK), and conventional Class F fly ash (FA) as a reference. SCMs were characterized and the fresh and hardened properties of concrete incorporating different dosages (i.e., 10, 20, and 30% cement replacement by mass) of the individual SCMs (i.e., binary systems) and blended SCM systems of RFA-MK …

Resilient 3d-Printed Infrastructure With Engineered Cementitious Composites (Ecc), Maryam Hojati

Publications

Conventional construction of reinforced concrete structures is slow, labor-intensive, and expensive. 3D printing holds great potential to assist engineers and architects in constructing fast and economical yet complex representational infrastructures. One of the most significant barriers to the broader adoption of concrete 3D printing in civil infrastructure is the difficulty of providing printed structural components with reinforcement to achieve sound structural performance under different loading conditions. Hence, it is essential to design concrete that can be utilized as a rebar-free material by considering strength and ductility. Recently, the development of Engineered Cementitious Composites (ECC) has neared the possibility to achieve …

Evaluation Of Sustainable And Environmentally Friendly Stabilization Of Cohesionless Sandy Soil For Transportation Infrastructure, Miladin Radovic, Anand Puppala, Surya Sarat Chandra Congress, Jungyeon Jang, Oscar Huang

Publications

Ordinary Portland cement (OPC) is generally used to stabilize cohesionless sandy soils that are often found in coastal areas. Due to its high carbon footprint, many studies are being conducted to identify a suitable green alternative for stabilizing cohesionless soils. Previous studies have shown that partially replacing OPC with waste materials such as nano-silica and coal waste reduces the overall carbon footprint without significantly impacting the performance. Geopolymer (GP) received a lot of attention in the past few decades owing to its similar properties to that of OPC yet with a lower carbon footprint. This study investigated the feasibility of …

An Automated System For Inspecting Rock Faces And Detecting Potential Rock Falls Using Machine Learning, John Stormont, Fernando Moreu, Amir Bagherieh, Roya Nasimi, Solomon Atcitty

Publications

Rockfall is a hazard in mountainous areas threatening infrastructure and human lives. Rockfall hazards are often mitigated by manual inspections using pry bars. The inspector must access the rock face, hit the rock surface, detect, and remove the loose rocks. This method is very labor demanding, unsafe, and challenging. This research presents a method that automatize the inspection of rock blocks that are prone to rockfall events. A robot is developed to replace the manual hammer tap process and collect the sound data remotely; subsequently, the sound signal is used to identify different types of the discontinuity in rocks in …

Resource Guide For State Dot’S Maintenance Equipment Fleet Management Decisions, Yongwei Shan, Samir Ahmed, Lei Qiao

Publications

This research created a guide for state Departments of Transportation fleet management on utilizing equipment fleet management system data to make informed fleet management decisions. The research team took the historical equipment fleet data from the Oklahoma Department of Transportation and developed workflows, algorithms, and examples to demonstrate the use of historical equipment data for equipment decisions. Specifically, the research team demonstrated 1) the use of life cycle analysis and dynamic programming models for equipment replacement decisions; 2) developed algorithms to calculate equipment rental rates that can be used by the Department to forecast and allocate equipment operational budget among …

Preventing Struck-By Hazards: Defying Risk-Habituation Via Virtual Accident Simulation, Changbum Ahn

Publications

Repeated exposure to struck-by hazards in road work zones generates workers’ habituation to risks related to those hazards, a key contributor to accidents in road work zones. Thus, analyzing the development of risk habituation and providing proper intervention are crucial to preventing accidents in road work zones. In this context, this study employs a virtual reality (VR) environment as a behavioral intervention tool to investigate its effect on mitigating a decline in workers’ vigilance with habituation to hazards in workplaces. A virtual environment that simulates a road maintenance task was developed and used to repeatedly expose subjects to struck-by hazards …

Bridge Cracks Monitoring: Detection, Measurement, And Comparison Using Augmented Reality, Fernando Moreu, Kaveh Malek

Publications

Crack occurrence and propagation are among critical factors that affect the performance and lifespan of civil infrastructures such as bridges. Consequently, numerous crack detection and measurement methods have been proposed and developed in the recent decades in the areas of Structural Health Monitoring and non-destructive testing. Many novel technologies have emerged with the potential to overcome the limitations of the presented techniques of crack detection and characterization. Crack detection and characterization method used in this research lies in supplementing human visual inspection capabilities in a systematic manner through an appropriate level of automation. The Augmented Reality (AR) tool developed in …

Maintenance And Restriping Strategies For Pavement Markings On Asphalt Pavements In Louisiana, Momen R. Mousa, Marwa Hassan

Publications

In Louisiana, most districts restripe their roadways using waterborne paints every other year; this strategy is questionable in terms of efficiency and economy. Meanwhile, previous studies showed substantial variability in the paint service life throughout the United States ranging between 0.25 and 6.2 years. Shortcomings in modeling the retroreflectivity of waterborne paints appear to significantly contribute to these variations as several studies predicted these values using degradation curves with a coefficient of determination (R2) as low as 0.1. Therefore, the objective of this study was to (i) develop new cost-effective restriping strategies using 4-inch (15-mil thickness) and 6-inch (25-mil thickness) …

Determination Of The Optimal Parameters For Self-Healing Efficiency Of Encapsulated Bacteria In Concrete Simulated Subtropical Climate, Momen R. Mousa, Marwa Hassan, Gabriel Andres Arce Amador, Ricardo Hungria, Andrea Gavilanes, Omar Kamal

Publications

Concrete is a remarkable construction material. However, its low tensile strength makes it prone to cracking, which negatively affects its durability. To address this issue, bacterial concrete has been implemented as a self-healing alternative due to its capability to seal microcracks through microbial-induced calcium carbonate precipitation (MICCP). In this study, a bacterial strain (i.e, Bacillus Pseudiformus) was encapsulated through three different methods: encapsulation through hydrogel beads, vacuum impregnation on lightweight aggregates, and attachment to cellulose nanocrystals. Furthermore, three precursor types were used, magnesium acetate, calcium lactate, and sodium lactate were implemented. Compressive strength tests and flexural strength tests were performed …

Development Of A Multi-Level Dynamic Model To Measure The Resilience Level Of Transportation Infrastructure Networks, Sharareh Kermanshachi, Jianling Li, Thahomina Jahan Nipa

Publications

The recent increase in disasters is making the largest critical infrastructure system namely the transportation infrastructure system susceptible to unexpected damage. Discontinuation of services provided by transportation infrastructures will create significant societal, economic, and collateral damages. Therefore, this study aims to identify dimensions to measure the resilience of the transportation infrastructures. This study also aims to develop a model to measure the resilience of the transportation infrastructures resilience. To fulfill the aims of this study, a questionnaire was developed which was supported by a comprehensive literature review. 92 valid responses were received and analyzed qualitatively and quantitatively. Statistically significant variables …

Alfred Russel Wallace Notes 18: Wallace On The Balance Of Nature, Charles H. Smith

Faculty/Staff Personal Papers

Alfred Russel Wallace (1823−1913) had a unique perspective on the ‘balance of nature’: he avoided classical thoughts on the subject, but nevertheless seems to have adopted elements of the ‘balance’ concept while acknowledging that irreversible change occurs at both the biological and environmental levels. Wallace’s position can be understood from his grounding in Humboldtian ‘equilibrium of forces’ thinking, and his turn toward ‘final causes’-based interpretations.

Incorporating Machine Learning Algorithm In Modified Quality By Design Approach On Simulated Penicillin Fermentation Dataset, Shengting Xu

Dissertations and Theses (Open Access)

For this thesis, we utilized random forest (RF) algorithm in combination with Quality by Design (QbD) in simulated commercial-scale penicillin production dataset. The RF algorithm was primarily used in the selection of critical process parameters (CPPs). In this analysis, the primary critical quality attributes (CQA) was set to be the final penicillin yield. After the CPPs were selected by the RF algorithm, we would propose design of experiment (DoE) by using fractional factorial design to establish mathematical relationships between CPPs and CQAs. Among the five RF models, we chose two models before proceeding to the DoE step. One using the …