Digital Commons Network^™

A Spreadsheet Algorithm For Determining The Economic Feasibility Of Micro-Chp Systems In The Arkansas Manufacturing Sector, Ford R. Lewallen

Graduate Theses and Dissertations

Combined heat and power (CHP) systems are not new to the market. However, advances in technology, specifically MicroTurbines, have presented new opportunities for installations of micro-CHP units - defined as 50 kWe to 300 kWe, specifically at small- to medium-sized industrial facilities. One pressing concern is whether or not an industrial plant has a high enough process thermal load requirement to fully utilize the energy output.

This thesis will discuss simulations that were run on several actual electric and thermal load combinations, which correspond to types of manufacturing facilities commonly found in Arkansas. Analysis of the plant usage profiles will …

Laboratory Resistivity Measurements For Soil Characterization, Behdad Mofarraj Kouchaki

Graduate Theses and Dissertations

Field based electrical resistivity measurements, such as electrical resistivity tomography (ERT) and capacitively coupled resistivity (CCR), are geophysical methods that offer a non-destructive and rapid means to collect continuous data. As such, ERT and CCR are becoming increasingly popular tools for geotechnical engineers; however, it is challenging to derive geotechnical information such as soil type, density, and water content from the data. A laboratory geophysical investigation was carried out to gain a better understanding of the parameters that affect the electrical resistivity of soils and devise a relationship between resistivity and soil type or classification. In this study, a soil …

Development Of Deep Site Specific And Reference Shear Wave Velocity Profiles In The Canterbury Plains, New Zealand, Michael Ryan Deschenes

Graduate Theses and Dissertations

Deep (typically >1000 m) shear wave velocity profiles were developed across the Canterbury basin at nine strong motion stations using a combination of active and passive surface wave methods and horizontal to vertical spectral ratio measurements. A multi-mode, multi-method joint inversion process, which included Rayleigh and Love wave dispersion and horizontal to vertical spectral ratio data, was used to estimate the shear wave velocity profiles at each site. A-priori geologic information was utilized in defining preliminary constraints on the complex geologic layering of the Canterbury basin. At sites where interbedded layers were present, velocity reversals were considered in the inversion. …

Geophysical Assessment Of Kinion Lake Dam, Tim Allen Moody

Graduate Theses and Dissertations

Geophysical methods including Capacitively-Coupled Resistivity (CCR), Electrical Resistivity Tomography/Imaging (ERT/ERI), Multichannel Analysis of Surface Waves (MASW) with Love and Rayleigh waves and a Full-Waveform Inversion (FWI) were performed on Kinion Lake Dam, an earth-filled embankment dam that has historically experienced significant seepage and internal erosion issues. Surveys were completed along the crest and downstream toe of the dam. Results from the surveys indicate that each method is capable of resolving the bedrock depth within 1-2 m of locations shown on previous drilling logs, though some discrepancies between the methods exist. A weathered bedrock layer is believed to have led to …

Mitigation And Evaluation Of Alkali-Silica Reaction (Asr) And Freezing And Thawing In Concrete Transportation Structures, Richard Albert Deschenes Jr.

Graduate Theses and Dissertations

An evaluation of alkali-silica reaction (ASR) and freezing and thawing (F/T) in concrete transportation structures is presented along with mitigation methods for slowing the rate of deterioration in concrete. A combination of field and laboratory testing confirms ASR deterioration is exacerbated by exposure to F/T. Laboratory testing indicates an aggregate previously deemed inert to ASR, caused ASR deterioration in several concrete pavement and transportation structures. Existing standard test methods deem this aggregate safe for use in concrete. A modified test method shows the concrete can deteriorate rapidly when subjected to cycles of conditions promoting ASR and F/T. Several structures containing …

Optimization Of Concrete Mixtures For Use In Structural Elements, Waleed Almutairi

Graduate Theses and Dissertations

Portland cement is an essential ingredient in concrete. The use of cement is to enhance the strength as well as other hardened properties of concrete mixtures. Determining the accurate amount of cement is important because the required strength may not be achieved if not enough cement is used. By contrast, when using too much cement, concrete cracking may occur that leads to reducing durability. Researchers at the University of Arkansas (UA) have shown that many bridge decks achieve their 28 day design strength of 4000 psi by 7 days of age. Bridge decks having high strength may experience cracking, which …

The Effects Of Sprayer Speed And Droplet Size On Herbicide Burndown Efficacy, Justin Carroll

Graduate Theses and Dissertations

An Apache AS1220 self-propelled boom sprayer with a 27.4 m (90 ft) boom was equipped with different sizes (02, 04 and 06) and types (TeeJet AI, XR, AIXR and TTI) of nozzles to achieve medium, very coarse and ultra coarse droplet sizes traveling 11 km/h (7 mph), 19 km/h (12 mph), and 29 km/h (18 mph). These combinations of speed and droplet size were evaluated for percent coverage of the spray and percent control of targeted weeds 3, 7, and 15 days after treatment (DAT). Four replications were conducted for each speed and droplet size combination except for at 19 …

Evaluating The Policies That Lead To Stem Educational Attainment At The University Of Arkansas For Transfer Students, Bryan Hill

Graduate Theses and Dissertations

The US has a critical need to produce more STEM graduates and that need is exponentially more critical in Arkansas. Arkansas currently ranks last in the percent of STEM degrees conferred compared to overall degrees awarded. Students intending to pursue a STEM four-year college degree who start at a two-year college are significantly less likely to succeed in earning that degree. Arkansas passed Acts 672 and 182 aimed at strengthening the success of students who transfer from two-year colleges into four-year institutions. This study sought to evaluate the effectiveness of the Acts by determining if the University of Arkansas (UA) …

Evaluating One-Step Catalytic Free Method Including Hydrolysis, Esterification, Transesterification, And Degradation Reactions To Produce Biodiesel From Soybean Oil, Mahmood Gheni Jebur

Graduate Theses and Dissertations

Due to the environmental and economic impacts of diesel fuel based on petroleum, several studies have been done to find an alternative source of energy. Biodiesel is considered one of these alternative sources. It is a renewable source of energy produced from vegetable oils and animal fats. There are two main reaction routes used to produce biodiesel (fatty acid methyl esters). Transesterification reaction is the first route used to convert triglycerides to fatty acid methyl esters (FAMEs), while hydrolysis followed by esterification reactions are the second route employed to convert triglycerides to free fatty acids (FFA) and then further converted …

Energy And Performance Balancing Architecture For Asynchronous Data Processing Platforms, Chien-Wei Lo

Graduate Theses and Dissertations

The semiconductor industry has been increasingly focused on the energy consumption and heat generation in CMOS-based integrated circuits (ICs) for its dominating impact on the system performance and reliability. Without clock-related timing constraints, asynchronous circuits have demonstrated unique flexibility in performance-energy tradeoffs compared to synchronous designs. This dissertation work presents the architecture capable of balancing energy and performance for asynchronous digital signal processing circuits using the Multi-Threshold NULL Convention Logic (MTNCL). Architecture implementing user-configurable adaptive dynamic voltage scaling (DVS) and data processing core disabling based on the detection and parameterization of system throughput are developed for MTNCL parallel homogeneous and …

A Laboratory-Scale Study On The Production Of High-Value Products From Broiler Litter Involving Solid-State Anaerobic Digestion And Mushroom Cultivation, Joe Barrett Carter Iii

Graduate Theses and Dissertations

There is a need to investigate alternate uses and treatments of broiler litter that lessen environmental impacts and decrease costs associated with its disposal. Anaerobic digestion is a biological process in which organic material is converted to a renewable fuel source. However, the substrate for anaerobic digestion often requires some form or pretreatment. Certain types of fungus have been investigated as a pretreatment for anaerobic digestion, one of which is Pleurotis ostreatus or the oyster mushroom, which also produces an edible fruiting body. Thus, this study was performed to investigate the use of broiler litter for oyster mushroom cultivation and …

Membranes For Food And Bioproduct Processing, Alexandru Marius Avram

Graduate Theses and Dissertations

Modified membranes for process intensification in biomass hydrolysis

Production of biofuels and chemicals from lignocellulosic biomass is one of the leading candidates for replacement of petroleum based fuels and chemicals. However, conversion of lignocellulosic biomass into fuels and chemicals is not cost effective compared to the production of fuels and chemicals from crude oil reserves. Some novel and economically feasible approaches involve the use of ionic liquids as solvents or co-solvents, since these show improved solvation capability of cellulose over simple aqueous systems. Membranes offer unique opportunities for process intensification which involves fractionation of the resulting biomass hydrolysate leading to …

Designing Secure Access Control Model In Cyber Social Networks, Katanosh Morovat

Graduate Theses and Dissertations

Nowadays, information security in online communication has become an indisputable topic. People prefer pursuing their connection and public relations due to the greater flexibility and affordability of online communication. Recently, organizations have established online networking sites concerned with sharing assets among their employees. As more people engage in social network, requirements for protecting information and resources becomes vital. Over the years, many access control methods have been proposed. Although these methods cover various information security aspects, they have not provided an appropriate approach for securing information within distributed online networking sites. Moreover, none of the previous research provides an access …

Peptide-Directed Nanoparticle Synthesis With A Denovo Pd-Binding Sequence Fused To A Reporter Protein, Rita Eloisa Tejada Vaprio

Graduate Theses and Dissertations

There is a need for low-cost nanoparticle materials in the context of new technologies for catalyst development. The purpose of this work was to recombinantly produce a 45- amino acid long metal binding peptide that is useful for nanoparticle synthesis. Using splicing by overlap extension PCR, a synthetic gene containing the fusion of the metal binding peptide with Green Fluorescent Protein (GFPUV) was constructed. The metal binding peptide, fused to reporter protein GFPUV, was expressed using high cell density fermentation. Palladium nanoparticles of an average diameter of 1.18 0.45 nm were synthesized by using the crude cell extract containing the …

Civic Tenderness: Love's Role In Achieving Justice, Justin Leonard Clardy

Graduate Theses and Dissertations

Martha Nussbaum’s work Political Emotions: Why Love Matters for Justice identifies the role that compassion plays in motivating citizens in a just society. I expand on this discussion by considering how attitudes of indifference pose a challenge to the extension of compassion in our society. If we are indifferent to others who are in situations of need, we are not equipped to experience compassion for them. Building on Nussbaum’s account, I develop an analytic framework for the public emotion of Civic Tenderness to combat indifference.

Civic tenderness is an orientation of concern that is generated for people and groups that …

Decision Support System For Container Port Selection Using Multiple-Objective Decision Analysis, Rivelino De Icaza

Graduate Theses and Dissertations

Ports are essential for maritime transportation and global supply chains since they are nodes that connect the sea- and land-based modes of transportation. With containerization and supply chains stimulating global trade, ports are challenged to adjust to changes in the market to create value to their customers. Therefore, this dissertation research focuses on the container port selection decision analysis to provide information to help shipping lines select the best port for their shipping networks. Since the problem is complex, dynamic, and involves multiple and conflicting criteria, the research proposes to use the multi-objective decision analysis with Value-Focused Thinking approach. The …

Operating System Identification By Ipv6 Communication Using Machine Learning Ensembles, Adrian Ordorica

Graduate Theses and Dissertations

Operating system (OS) identification tools, sometimes called fingerprinting tools, are essential for the reconnaissance phase of penetration testing. While OS identification is traditionally performed by passive or active tools that use fingerprint databases, very little work has focused on using machine learning techniques. Moreover, significantly more work has focused on IPv4 than IPv6. We introduce a collaborative neural network ensemble that uses a unique voting system and a random forest ensemble to deliver accurate predictions. This approach uses IPv6 features as well as packet metadata features for OS identification. Our experiment shows that our approach is valid and we achieve …

Intravenous Administration Of Iron Oxide Nanoparticles In The Chicken Model, Huong Thi Ngoc Le

Graduate Theses and Dissertations

To be used in health care, the safety and effectiveness of nanoparticles needs to be tested in a living organism. The objective of this project was to develop the chicken as a convenient animal model to examine tissue targeting of intravenously (i.v.)-injected iron oxide (IO) nanoparticles. In Experiment 1, different doses of IO-COOH were i.v. injected into chickens; blood was collected at 0, 5, 15, 30, and 60 minutes post-injection; liver, spleen, lung, and kidney were collected after the last blood collection. For Experiment 2, IO-COOH and IO-PEG were i.v. injected into chickens; blood and the organs were collected at …

Is It We Or They? The Effect Of Identity On Collaboration And Performance In Buyer-Supplier Relationships, Siqi Ma

Graduate Theses and Dissertations

In today’s scale-driven and technology-intensive global economy, collaboration becomes the supply chain’s core capability (Liker and Choi, 2004). A well-developed ability to create and sustain fruitful collaborations gives companies a significant competitive advantage (Kanter, 1994). Retailers are increasingly relying on their suppliers to reduce costs, improve quality, and develop new processes and products faster than their rivals’ vendors can. On the other hand, suppliers benefit from retailers that they are able to monitor store-level demand in real time in order to ensure the top-selling items are in-stock or the accuracy and timeliness of retailer’s demand forecast. Previous literature has shown …

The Bicycle, The Unsuitable Substitute:A Feasibility Study Based In Fayetteville, Ar Using A Bicycle As A Year-Round Replacement For An Automobile, Jamey Voorhees

Graduate Theses and Dissertations

Can a bicycle can be used in place of an automobile for everyday transportation and commuting needs? Fayetteville, Arkansas is a bicycle friendly and they plan continue to expand the current trail system improve other components in the future. Alternative transportation forms like the bicycle are important but only if bikes are integrated into traffic which needs to be done in some way that all involved understand their place in the system. By actively participating in this system I have attempted to show that a bicycle is just not feasible as a form of daily transportation in a city like …

Mushroom Inoculation On Switchgrass Feedstock During Storage: Effects Of Subsequent Pre-Processing For Intended Biofuels Production, Amandeep Singh Turay

Graduate Theses and Dissertations

The objective of this project was to examine the effect of fungal treatment and liquid hot water pretreatment of switchgrass combine in view of increasing glucose release. The fungal treatment consisted of incubating Pleurotus ostreatus in square switchgrass bales, at 50% moisture content for 25 days, 54 days, and 82 days. The digestibility of the switchgrass biomass was subsequently evaluated using Accelerase 1500 enzyme. Lignin is an important barrier to enzymatic hydrolysis, and it was stipulated that incubation with P. ostreatus would disrupt plant cell walls, resulting in enhanced saccharification. Three different concentrations of P. ostreatus were evaluated: 0%, 2%, …

Statistical Movement Classification Based On Hilbert-Huang Transform, Shanqi Sun

Graduate Theses and Dissertations

The goal of this project is to introduce an automatic movement classification technique of

finger movement signals using Hilbert-Huang Transform (HHT). Due to the nonlinear and

nonstationary processing behavior, movement signals are analyzed with the Hilbert-Huang

Transform (HHT). The slope of auto-correlation function and mean of frequency from first

three Intrinsic Mode Functions (IMFs) was used as feature parameters for each category.

Finally, performing support vector machine (SVM) for pattern classification completes clas-

sifying types of finger movement. According to the records of 669 trial samples of two types

of finger movement signals (thumb and pinky), average accuracy is 93.28%. …

Effects Of Filtration Conditions On Clearance Of Bacteriophage, Rigen Te

Graduate Theses and Dissertations

Virus Clearance is one of the major challenges in biopharmaceutical industry, especially in the manufacturing of drugs. U.S. Food and Drug Administration (FDA) recommends using several model bacteriophages as surrogates of pathogenic mammalian virus for process validation. In this work, two bacteriophages were tested against 30 kDa, 100 kDa, 300 kDa polyethersulfone (PES) membranes to investigate the effects of pore size on virus clearance. Virus particles were spiked into the protein feed solutions containing bovine serum albumin (BSA) or lysozyme at different concentrations. Besides protein concentration, the effects of feed pH on the filtration performance and virus rejection were also …

Optimization Of Miniaturized Resonant Microwave Cavities For Use In Q-Thrusters, Joshua Steven Pennington

Graduate Theses and Dissertations

A gedankenexperiment was considered to compare a hypothetical thruster that used no reaction mass to propulsion methods currently in use. A brief discussion of previous research work done on closed resonant cavity thrust devices was conducted. Using the previous work as a template, a simulation plan was devised. Computational models of resonant microwave cavities were constructed and investigated using COMSOL software. These COMSOL simulations were verified against known analytical solutions using Matlab software as a computational tool. Multiphysics simulations were created to study the microwave heating environment of the resonant cavities. From the COMSOL study outputs, the electromagnetic field magnitude, …

The Bracero Program In The Arkansas Delta: The Power Held By Planter Elite, William Chase Whittington

Graduate Theses and Dissertations

This paper examines the Bracero Program and its implementation from the start of World War II to the end of the program in 1964. Farmers and planters in America needed a sufficient labor supply once the war started, and Mexico became the main supplier. The Bracero Program was initiated as a war effort and meant to only last until the end of the war, but the planter elite had far different intentions once they realized how productive and inexpensive the program could be. This paper identifies the leading causes for how the Bracero Program was able to last over twenty …

Peptoid-Based Microsphere Coatings For Use As Tunable Biocompatible Interfaces, German Raul Perez Bakovic

Graduate Theses and Dissertations

The pursuit of sensitive, non-invasive, and cost efficient diagnostic tools for early stage disease detection have led to the development of sophisticated biosensor technologies for proteomic studies. As these markers increase in complexity, the role of support substrates grows increasingly important. Limitations in existing support substrates include the potential for increased sensitivity, binding specificity, and bio-stability. Ideal support substrates need to provide biocompatible and bioresistant surfaces, that offer high surface areas for binding, and enables the incorporation of diverse chemistries. The use of peptoids as the basis for the deposition of uniform microsphere coatings offers a mean to the attainment …

A Comparative Analysis Of Feed And Environmental Factors On Broiler Growth In The United States, Alexandra Gulli

Graduate Theses and Dissertations

Broiler production in the United States has become an important industry within the last half century. As the demand for poultry continues to increase and the concern of climate change also increases, it will become an important part of the industry to become more sustainable. This study uses a feed optimization model, a broiler growth model, and a life cycle assessment (LCA) to determine how feed ingredients and the barn environment can affect the broiler’s growth and production emissions. A multi-criteria ration optimization model is used to produce feeds based on carbon footprint and cost. A growth model is used …

Improvement In Simple Artificial Insemination In Sheep Using Chilled Extended Semen And Consideration Of Fertility In Ewes, Mohan Acharya

Graduate Theses and Dissertations

Three studies were conducted to improve simple artificial insemination in sheep using chilled extended semen and evaluate methods to predict fertility in ewes. The first study evaluated the effect of semen extenders and storage temperature on motility parameters of ram semen stored for up to 72 h. Single semen collected from each ram was divided into four parts and extended using four extenders: milk, TRIS, TEST, and CJ-2, diluted to 600 million sperm/ml and loaded into 0.25 ml straws for storage at 4 and 15° C. Most of the CASA motility parameters were higher after extension and storage at 4 …

Evaluation Of Screening Methods To Detect Heat Stress In Diverse Cotton Genotypes, Mathilda M. Van Der Westhuizen

Graduate Theses and Dissertations

Cotton (Gossypium hirsutum L.) is sensitive to heat stress (HS) during reproductive development. The objective of this study was to evaluate different screening methods for identification of heat tolerance in cotton genotypes. Three growth chamber studies and four field trials were conducted from 2014 to 2017 using genotypes Arkot 9704, VH260, DP 210 B2RF and DP393. Measurements were made of membrane leakage (ML), chlorophyll fluorescence (ChlF), glutathione reductase (GR), and sucrose concentration. In the growth chambers, measurements were made at 30 and 40°C and at 2, 4 and 6 hours of HS, as well as 3 and 7 days after …

Realization Of A High Power Microgrid Based On Voltage Source Converters, Yusi Liu

Graduate Theses and Dissertations

Microgrid concepts are gradually becoming more popular because they are expected to interface with renewable energies, increase end users’ reliability and resiliency, and promote seamless integration of distributed generators (DG) and energy storage units [1]. Most units are connected through power electronics interfaces, such as ac-dc, dc-dc, and dc-ac converters. The converter design and control are critical to the stability and efficiency of a microgrid.

A microgrid may operate in either gird connected mode or islanded mode [1]. In terms of stability, the grid connected mode is less challenging compared to the islanded mode of operation due to the nearly …