Engineering Commons^™

Comparing Layer Types For The Use Of Mepdg For Fdr Design, Sadie Smith

Graduate Theses and Dissertations

While Full Depth Reclamation (FDR) has many potential cost and environmental benefits, especially over the lifetime of the pavement, it is necessary to be able to ensure that the recycled pavement will perform adequately. One way in which this can be accomplished is understanding how to best complete the structural design of FDR pavements. Because FDR is a combination of several different layers of material pulverized, mixed, stabilized and re-compacted, it does not fit neatly into any of these predetermined types of materials considered by the Mechanistic Empirical Design Guide (MEPDG). Current practice is to treat FDR as an unbound …

Three Dimensional Simulations Of Tornado Sheltering Effect Of Man-Made Structures, Piotr Gorecki

Graduate Theses and Dissertations

A three dimensional computational fluid dynamics (CFD) model was utilized to investigate tornado-like vortex interactions with wide man-made structures. The tornado-like wind profile was approximated using Rankine vortex model. By utilizing the CFD model, it was explained why tornadoes exhibit less damage on leeward side of large structures. During the preliminary stage of this study, a perpendicular vortex-prism interaction was analyzed. The prism height and the length were equal to the vortex core radius. The prism was also 12 times wider than the vortex core radius. During the vortex-prism interaction, the near-ground portion of the vortex was blocked by the …

Amount Of Uncertainty In The Methods Utilized To Design Drilled Shaft Foundations, Morgan Race

Graduate Theses and Dissertations

In 2001, load and resistance factor design (LRFD) for deep foundations was required by the American Association of State Highway and Transportation Officials (AASHTO). Following implementation of LRFD, localized calibration of resistance factors using data from the states of Colorado, Florida, Kansas, Louisiana/Mississippi, Missouri allowed these states to utilize higher resistance factors during design. However, characterizing the uncertainty in the design of DSF, regarding the geotechnical investigation methods and the utilized software programs, higher values of resistance factors may be calibrated to more efficiently design DSF with the same level of reliability.

Three test sites within the state of Arkansas, …

Characterization Of Nano-Porous Si-Cu Composites To Enhance Lubricant Retention Impacting The Tribological Properties Of Sliding Surfaces, Julius Sheldon Morehead

Graduate Theses and Dissertations

As the expectations for modern machinery's tribological and thermal performances continue to rise, the retention of lubricant on the contact surfaces of their sliding components becomes an increasingly important issue. Friction and wear cause heat-related failures which lead to catastrophic damage to machinery. Evaporation of a lubricant's volatile constituents as well as lubricant migration leads not only to a reduction in lubricant quantity but also in its quality, thus facilitating component failures. In order to enhance component reliability, the surface should incorporate features that actively retain lubricants. The unique properties of nano-porous topographies such as their high surface area-to-volume ratio …

Development Of Best Management Practices For Turbidity Control During Rainfall Events At Highway Construction Sites Using Polyacrylamide, Joanne Johnson

Graduate Theses and Dissertations

In 2009, the United States Environmental Protection Agency (EPA) promulgated a national turbidity standard for runoff water leaving highway construction sites at 280 nephelometric turbidity units (NTU). Meeting this standard can be challenging as turbidities of runoff waters can exceed 15,000 NTU. The objective of this research was to assess polyacrylamide (PAM), a coagulant aid used in water treatment, to help meet the EPA turbidity regulation. Twelve commercially available PAM types were studied, selected on the basis of charge type (cationic, nonionic, anionic), charge density (0-100%), and molecular weight (0.1-28 Mg mol-1). Jar tests were conducted with runoff waters from …

Measurement Of Transfer And Development Lengths Of 0.7 In. Strands On Pretensioned Concrete Elements, Canh Ngoc Dang

Graduate Theses and Dissertations

The implementation of 0.7 in. (17.8 mm), Grade 270 (1860), low-relaxation prestressing strands in construction is slow regardless of its advantages over the use of 0.6 in. (15.2 mm) and 0.5 in. (12.7 mm) strands. The limited research data and unavailable design guidelines partially account for the slow utilization. This study measured transfer and development length, and evaluated applicable strand spacing of 0.7 in. (17.8 mm) prestressing strands for 24 pretensioned concrete beams. Each beam contained one prestressing strand or two prestressing strands placed at spacing of 2.0 in. (51 mm). The beams were fabricated with high strength, conventional concrete …

Achieving Enhanced Treatment Of Produced Fluids Using Ozone, Hydrogen Peroxide And Electrochemical Oxidation: Full Scale Evaluations, Jamar Willis Blackmon

Graduate Theses and Dissertations

The main focus of the present work was to expand the existing knowledge in using an advanced oxidation process for produced water treatment. Produced water is a phrase used in the oil and gas industry to describe water that is produced as a waste byproduct together with oil and gas. Historically produced water was pumped down disposal wells as a waste product. Due to increasing demand, limited supply and stricter regulation on fresh water sources, exploration and production companies have been compelled to recycle produced waters in many parts of their operations around the world.

Produced water quality varies dramatically …

Maritime Transportation Research Bank, Valeria A. Remon Perez

Industrial Engineering Undergraduate Honors Theses

The maritime transportation system is an important component of the United States’ (U.S.) economy, from commerce activities to freight movement to disaster’ relief. The annual impact of the maritime transportation system on the U.S. national economy is reported as approximately $649 billion of the total U.S. gross domestic product (U.S. Department of Transportation Maritime Administration, n.d.). This impact is attributed to activities related to the movement of goods and people. Indeed, the maritime transportation system plays an important role in international trade by transporting goods such as coal and farm products, which are common commodities for foreign and domestic commerce …

Prioritizing Interdictions On A Shortest Path Network, Hayden D. Summerhill

Industrial Engineering Undergraduate Honors Theses

We consider a variant to the shortest path network interdiction problem with symmetric information from Israeli and Wood (Networks 40, 97-111,2002) which arises in the context of nuclear smuggling prevention. In the basic shortest path interdiction problem, an interdictor has a limited number of interdictions with which he can lengthen arcs in a network in order to maximize the length of the network’s shortest path. This thesis considers the case in which the interdictor does not make all of the interdictions at once. Rather, the interdictor must make the interdictions over a set number of periods. Each period has a …

Characterization And Development Of Tsi Three-Dimensional Laser Doppler Velocimetry System, John Andrew Dominick

Chemical Engineering Undergraduate Honors Theses

The study of dense gas dispersion at atmospheric conditions is critical to understand the safety concerns of industrial operations where large amounts of toxic or flammable materials are stored and generated. A large airborne release of these materials into the atmosphere could have catastrophic effects. The Chemical Hazards Research Center (CHRC) at the University of Arkansas performs important research on dense gas dispersion. The CHRC houses the world’s largest ultra-low speed wind tunnel, which is used to simulate dispersion at atmospheric conditions. Substantial amounts of data, including velocities, are recorded for modeling real life gas dispersion events. Before conducting experiments, …

Sensitivity Analysis Of Dredge Fleet Scheduling, Kaitlin Denny

Industrial Engineering Undergraduate Honors Theses

Each year, the U.S. Army Corps of Engineers (USACE) is tasked with conducting maintenance dredging at hundreds of project sites throughout the country. The USACE must take into account factors such as environmental windows, increased transportation distances, increased operational time because of reduced vessel speeds, and personnel availability constraints. Environmental windows are intended to minimize the environmental impact of dredging while protecting biological resources and their habitats from potentially detrimental effects. The objective of this research is to perform sensitivity analysis of the performance of this model (cubic yards dredged) and how it is impacted by individual environmental window elimination …

Evaluating The Viability Of Graphene Oxide For The Removal Of Ni(Ii) Ions From Waste Water, Cale M. White

Biomedical Engineering Undergraduate Honors Theses

When levels of heavy metal ions such as nickel (Ni), copper (Cu), lead (Pb), Zinc (Zn), and Cobalt (Co) exceed the tolerance values for industrial wastewater, it can devastate the environment as well as the health of the individuals consuming the water. Heavy metal ions are not biodegradable and will accumulate in organic matter.(1) This accumulation leads to toxic levels in the blood and hence damage to nerve tissue, kidneys, the liver, and other vital organs. (2) Effective removal processes of these heavy metals from water must be developed. This study explores a method to adsorb nickel from water with …

Effect Of Sodium Acetate On Butanol Production By Clostridium Saccharoperbutylacetonicum Via Abe Fermentation, Brigetta Super

Chemical Engineering Undergraduate Honors Theses

Clostridium saccharoperbutylacetonicum is used in ABE fermentation which historically produces a solvent mixture of 3:6:1 parts acetone, butanol, and ethanol respectively. The fermentation process undergoes two phases, an acidogenesis phase which produces butyric acid, and a solventogenic phase which reutilizes the butyric acid, making butanol. For ABE fermentation to compete economically with butanol production from petroleum, the concentration of butanol in the solvent product must be increased dramatically. Unpublished research by Carver student Kayla Kimbrough in the summer of 2012 showed that the addition of salts (sodium acetate) to PYG fermentation media increased butanol production from Clostridium saccharoperbutylacetonicum significantly. When …

High Temperature Cmos Silicon Carbide Asynchronous Circuit Design, Landon John Caley

Graduate Theses and Dissertations

Designing a digital circuit to operate in an extreme temperature range is a challenge with increasing demand for a solution. Large variations in temperature have a distinct impact on electron mobilities causing substantial changes to the threshold voltage of the devices. These physical changes affect the setup and hold times of clocked components, such as D-Flip Flops, of a traditional synchronous digital circuit. Focusing primarily on high temperature circuit operation, this dissertation presents a digital circuit design methodology pairing an asynchronous circuit design paradigm called NULL Convention Logic (NCL) as well as traditional Boolean circuitry with a wide-bandgap semiconductor material, …

A Pump Monitoring Approach To Irrigation Pumping Plant Performance Testing, William Merritt Mcdougall

Graduate Theses and Dissertations

Traditionally, irrigation pumping plants have been tested using an instantaneous appraoch, which tests performance parameters over a very short time interval. Using this method, the tester measures the necessary work and energy use parameters to calculate the desired pumping plant performance values. The primary limitation of this approach is its inability to determine the season long efficiency of an irrigation pumping plant.

A new approach to evaluating irrigation pumping plant performance is the use of pump monitoring systems which use high frequency, real-time data collection and telemetry to relay information directly from the pump to the user. This method of …

Enabling Runtime Self-Coordination Of Reconfigurable Embedded Smart Cameras In Distributed Networks, Franck Ulrich Yonga Yonga

Graduate Theses and Dissertations

Smart camera networks are real-time distributed embedded systems able to perform computer vision using multiple cameras. This new approach is a confluence of four major disciplines (computer vision, image sensors, embedded computing and sensor networks) and has been subject of intensive work in the past decades. The recent advances in computer vision and network communication, and the rapid growing in the field of high-performance computing, especially using reconfigurable devices, have enabled the design of more robust smart camera systems. Despite these advancements, the effectiveness of current networked vision systems (compared to their operating costs) is still disappointing; the main reason …

Characterization Of Silicon Phosphorus Alloy For Device Applications, Larry C. Cousar

Graduate Theses and Dissertations

A new material of highly-phosphorus doped silicon for device applications was characterized and analyzed for new material properties. Devices such as NMOS transistors and other CMOS compatible devices may benefit from new materials that reduce external resistances and increase drive currents.

Material characterization requires numerous techniques and technologies to determine electrical, optical, and physical characteristics. For this work, Hall measurement, X-ray Diffraction, Raman Spectroscopy, Photoluminescence Characterization, and Spectroscopic Ellipsometry were used to better understand this new material. The results may lead to new models for silicon phosphorus alloys.

Separation Of Emulsified Oil From A Brackish Water Stream Using Ultrafiltration And Coalescence, Casey W. Polk

Chemical Engineering Undergraduate Honors Theses

In the past 40 years, a variety of enhanced oil recovery (EOR) methods have been developed and applied to mature, mostly depleted, and shale formation oil reservoirs. Chemical and sonic stimulation are two enhanced oil recovery methods in which emulsions are created either as a primary or secondary effect. The resulting viscosity of the oil in water emulsion is considerably lower than that of dry crude, thus increasing recovery from pay zones. During chemical enhanced oil recovery, caustic or surfactants are injected into oil reservoirs, which results in the creation of stable oil-water emulsions. The emulsions from chemical enhanced oil …

Electrocoagulation For Sulfate Removal, Michael A. Layton

Chemical Engineering Undergraduate Honors Theses

In the United States, one of the major rising issues is water shortage, especially in Western, inland states with arid climates. Not only do deficiencies exist for potable water, but for irrigation and agricultural purposes as well. Currently, the Brackish Groundwater National Desalination Research Facility in Alamogordo, New Mexico has four separate wells that are being used for experimentation. A major concern is that a considerable amount of this water is currently wasted by being sent to evaporation ponds without any sort of treatment for human consumption. The WERC-A-HOLICS have identified two possible methods to alleviate this problem. Electrocoagulation (EC) …

Inertial Force-Driven Synthesis Of Near-Infrared Plasmonic Nanosphere Composites: Physicochemical Characterizations, Joseph Noel Batta-Mpouma

Graduate Theses and Dissertations

Near-infrared (NIR) responsive nanoparticles (NPs) like gold nanorods (GNRs) are important in biomedical fields because of their transparency for biological tissues. Although GNRs are sought after as contrast agents for theranostics in cancer studies, capping ligands like cetyltrimethylammonium bromide (CTAB) for the GNR synthesis are toxic for biological tissues. The need for an alternative to toxic GNRs is of interest to alleviate the problem.

This work aimed to optimize the synthesis of NIR responsive nanosphere composites (NSCs) by inertial force (g-force) using colloidal gold NPs as model, elucidate the mechanism for the NSC formation, and study their detailed physicochemical characteristics. …

Transformation Of Swine Manure And Algal Consortia To Value-Added Products, Mahmoud A. Sharara

Graduate Theses and Dissertations

The swine production sector is projected to grow globally. In the past, this growth manifested itself in increased herd sizes and geographically concentrated production. Although economically sound, these trends had negative consequences on surrounding ecosystems. Over-application of manure resulted in water quality degradation, while long-term storage of manure slurries was found to promote release of potent GHG emissions. There is a need for innovative approaches for swine manure management that are compatible with current scales of production, and increasingly strict environmental regulations.

This study aims to investigate the potential for incorporating gasification as part of a novel swine manure management …

A Study Of The Influence Of Particle Gradation In Bonded Assemblies, Matthew P. Watters

Civil Engineering Undergraduate Honors Theses

The discrete element method (DEM) has been used extensively to study soil, rock, and masonry behavior because of its ability to model the materials as individual particles or bonded clumps of particles. DEM allows for examination of the macro- and micro-scale response and provides a means to study the fundamental material behavior, but it is still considered computationally expensive in relation to other methods. To lower computational costs, the smallest particle sizes are often considered negligible and are left out of the model. Additionally, rock or intact materials are often modeled as a bonded assembly of uniform spheres. To date, …

Fractionation Of Chitosan Using A Novel Precipitation Method, Davis J. Ward

Biomedical Engineering Undergraduate Honors Theses

Chitosan is a derivative of chitin, a biopolymer found in the exoskeletons of crustaceans. Chitosan is under heavy investigation in the field of drug delivery due to its wide versatility. One such delivery mechanism is the use of hydrogels in cancer immunotherapy delivery. The viscosity of chitosan in its use as a hydrogel depends on the length of chitosan’s N-acetyl D-glucosamine chains, which in turn determines the molecular weight of chitosan. Because there is such a wide range of viscosity in a typical sample of chitosan, there is a need for a simple technique to fractionate the chitosan based on …

A Study On The Be2100 Noninvasive Biomass Sensor As An Instrument For Measuring Optical Density During Fed-Batch Fermentation At Various Stir Rates, Hannah Moreland

Biological and Agricultural Engineering Undergraduate Honors Theses

Fusion proteins, engineered proteins that combine the DNA sequences and therefore properties of two different proteins, can be used in a variety of therapeutic purposes. One example of a therapeutic fusion protein is collagen binding domain-parathyroid hormone glutathione-S-transferase (CBD-PTH-GST), which can combat osteoporosis by binding specifically to collagen in the vertebral column and promoting bone growth through the release of calcium. This fusion protein is being expressed with Escherichia coli at the University of Arkansas through fed-batch fermentation, a method that produces large volume of cells through fermentation in a controlled environment in a bioreactor. It is necessary to track …

The Investigation Of Chitosan-Based Hydrogels For Intratumoral Delivery Of Immunotherapeutic Cytokines, Ethan Drew Lowry

Biomedical Engineering Undergraduate Honors Theses

Controlled and localized delivery of Interleukin 12 (IL-12) is critical to effective and non-toxic cancer immunotherapy. Current delivery protocols for pre-clinical anti-tumor trials utilize solutions of chitosan, a mucoadhesive and bioeliminable biopolymer, to slow the release of IL- 12 into the tumor microenvironment. In order to further increase IL-12 retention, we have developed and characterized two chitosan-based in situ gelling hydrogels for IL-12 immunotherapy. One hydrogel, composed of heparin and chitosan, is herein described from initial conception through multiple stages of characterization including isolation of a range of suitable hydrogel formulations and observational physical and chemical properties. A second hydrogel …

Fluorescent Imaging On A Microfluidics Chip For Quantification Of Leukocyte Count, Aneeka Majid

Biomedical Engineering Undergraduate Honors Theses

We have demonstrated a method for conducting a leukocyte count in whole blood using a microfluidics chip and epi-fluorescence setup. Leukocyte counts provide physicians with a wealth of information about a patient’s medical condition and as such are routinely completed for many hospital visits. Miniaturization of this diagnostic tool may enable physicians to provide healthcare in resource-limited settings, where patients would otherwise not receive this test. The microfluidics chip was fabricated in polydimethylsiloxane (PDMS) using soft-film lithography. Following further processing and cleaning, the PDMS mold is exposed to UV-ozone for surface activation, and then sealed with a glass coverslip to …

Monitoring The Effects Of Mmp Inhibitors On Extracellular Matrix Degradation For Use In Implant Protection, Jake D. Jones

Biomedical Engineering Undergraduate Honors Theses

In order to lengthen the functional time of implantable ECM, the mechanism of degradation must be inhibited. The matrix metalloproteases are the primary method by which ECM is broken down, and the TIMP family of proteins exists as proof that inhibition of these proteases is possible naturally. In particular, the glycoprotein TIMP-1 plays an inhibitory role with most of the MMPs including the collagenases. Furthermore, there exist synthetic or chemical molecules that likewise inhibit the catalytic actions of MMPs. One such molecule is Batimastat (BB-94) which has been proven to be a dose dependent inhibitor of MMPs during the inflammatory …

Development Of An In Vitro Myogenesis Assay, Anna Arnaud

Biomedical Engineering Undergraduate Honors Theses

The objective of this study was to explore the interaction between mouse C2C12 cells and the extracellular matrix, particularly the process of myoblasts converting to myocytes. This study aimed to create a myogenesis assay that presents a process to effectively monitor the development of mouse C2C12 myoblasts into differentiated skeletal myotubes through detection of the protein MyoD. Myogenesis, the development of muscle tissue, occurs when muscle progenitor cells, myoblasts, fuse to form multinucleated myotubes, followed by cell fusion and resulting in a myofiber capable of contraction. An in vitro myogenesis assay would enable further research to efficiently test the effect …

Multiplexed Microfluidic Loop-Mediated Isothermal Amplification Of The 16s Rrna Gene For The Diagnosis Of Neonatal Sepsis In Resource-Limited Environments, Griffin Thomas Sonaty

Biomedical Engineering Undergraduate Honors Theses

Bacterial infection, or sepsis, places a disproportionately high burden on newborns in developing countries. This is due in part to a lack of diagnostic tools suitable for sustainable use in resource-limited nurseries. One potential vehicle for a new diagnostic assay is loop-mediated isothermal amplification (LAMP), a high-yield DNA amplification method. LAMP has been used to detect single genes from bacteria in blood serum samples to aid in sepsis diagnosis. While specific, this approach can only provide detection for one species at a time. LAMP could be adapted to detect a broader set of bacteria, while retaining a degree of specificity …

Intracellular Uptake Of Chitosan Nanoparticle-Based Vaccines, Katherine E. Wilson

Biomedical Engineering Undergraduate Honors Theses

Particle-based delivery systems are a promising approach to enhance antigen-specific immunity for use in vaccines. Chitosan, a natural polysaccharide derived from the exoskeletons of crustaceans, shows great potential as a vaccine carrier due to its favorable properties as a biomaterial, including biocompatibility and biodegradability. In this study, the intracellular uptake of chitosan nanoparticles is explored and compared to that of other commonly used particle-based delivery vehicles, such as poly (lactic-co-glycolic acid) (PLGA). Fluorescein isothiocyanate-labeled bovine serum albumin (FITC-BSA) was used as a model protein antigen and encapsulated in both chitosan particles via precipitation-coacervation and PLGA particles via double emulsion solvent …