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Articles 1 - 25 of 25
Full-Text Articles in Engineering
Solid-State Transformers For Interfacing Solar Panels To The Power Grid: An Optimum Design Methodology Of A High Frequency Transformer For Dc-Dc Converter Applications, Kenny George
Inquiry: The University of Arkansas Undergraduate Research Journal
Nowadays the use of power electronic interfaces to integrate distributed generation with the power grid is becoming relevant due to the increased penetration of renewable energy sources like solar, and the continued interest to move to a smarter and more robust electric grid. Those interfaces, which also provide a voltage step-up or step-down function, are of particular interest because renewable energy sources do not always have voltages compatible with the connecting grid. Among them, the so-called “power electronic transformer” or “solid-state transformer” (SST) is the focus of significant research. Advantages such as bidirectional power flow, improved system control, reduced size, …
Multiplexed Loop-Mediated Isothermal Amplification Of The 16s Rrna Gene For The Diagnosis Of Neonatal Sepsis In Resource-Limited Environments, Griffin T. Sonaty
Multiplexed Loop-Mediated Isothermal Amplification Of The 16s Rrna Gene For The Diagnosis Of Neonatal Sepsis In Resource-Limited Environments, Griffin T. Sonaty
Inquiry: The University of Arkansas Undergraduate Research Journal
Sepsis, or dysregulated inflammation caused by bacterial infection, 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 previously been used to detect genes from single species of bacteria in blood serum samples to aid in sepsis diagnosis. LAMP could be adapted to detect a broad set of bacteria, while retaining a degree of specificity that allows clinicians to begin directed antimicrobial …
Terahertz Imaging Platform To Characterize The Growth Of In-Vitro Breast Tumors, Scarlett-Marie Acklin
Terahertz Imaging Platform To Characterize The Growth Of In-Vitro Breast Tumors, Scarlett-Marie Acklin
Inquiry: The University of Arkansas Undergraduate Research Journal
This study aimed at evaluating the ideal plating method and density for imaging with the terahertz (THz) spectrometer. In this study, different methods were used to grow in-vitro tumors using the 4T1 cell line. Here, attempts to grow breast tumors in-vitro were conducted. Results were produced in two environments, flat-bottomed plates and round-bottomed multiwell plates. The second method allowed for faster clumping and increased cell aggregation, producing tumors up to 7mm. Terahertz spectroscopy produced images that correlated well to photomicrographs taken of the in-vitro tumors. This methodology shows great promise for providing a reliable, parameter-controlled source of in-vitro breast tumors …
Interface Property Of Collagen And Hydroxyapatite In Bone And Developing Bioinspired Materials, Clint Paul
Interface Property Of Collagen And Hydroxyapatite In Bone And Developing Bioinspired Materials, Clint Paul
Inquiry: The University of Arkansas Undergraduate Research Journal
Bone at the nanoscale consists of type I collagen and hydroxyapatite (HAP). Type I collagen and HAP [Ca10(PO4)6(OH)2] are responsible for most of the structural integrity of bone. Collagen fibrils contain HAP platelets of varying size dispersed between the collagen. We investigate heterotrimeric collagen interaction with HAP using Steering Molecular Dynamics to obtain the force-displacement relation as the collagen is undergoing shearing and peeling on the surface of HAP. Results indicate that the collagen requires 40% less force to separate form the HAP surface under peeling, when compared to shear loading conditions. In both shearing and peeling, the number of …
A New Design Method For Vanadium Redox Batteries In Renewable Energy Systems, Casey Gibson, Karla G. Morrissey Unversity Of Arkansas, Fayetteville
A New Design Method For Vanadium Redox Batteries In Renewable Energy Systems, Casey Gibson, Karla G. Morrissey Unversity Of Arkansas, Fayetteville
Inquiry: The University of Arkansas Undergraduate Research Journal
This study investigated the behavior of vanadium redox flow batteries (VRFBs), which are batteries capable of easily switching between charging and discharging modes, making them a suitable option for storing intermittent sources of alternative energies (solar, wind, etc). Since different sizes of the battery provide varying voltages, optimal parameters for a particular home are key for implementation. These parameters, specifically the cell and tank volumes of the battery that are capable of providing consistent on-load voltage, were determined using data from a 13 kW solar array and a medium-sized house. Charge/discharge current values were used to run a mathematical model …
Preparation Of New Versatile And Implantable Titanate Nanofiber-Bioscaffolds Via Efficient Cation Exchanges, Keaton Piper
Preparation Of New Versatile And Implantable Titanate Nanofiber-Bioscaffolds Via Efficient Cation Exchanges, Keaton Piper
Inquiry: The University of Arkansas Undergraduate Research Journal
For the first time in the implantable biomaterials field, efficient hydrothermal cation exchange methods were developed suitable for mass-production of implantable material. The cation exchange conditions were performed by various methods of temperature, pressure, and time exposure. To confirm both chemical and physical alteration of the scaffold, XRD shift analysis, EDX atomic composition, and SEM imaging were conducted. The optimal results are to use aqueous solutions of 0.5 M chloride salts in sealed heated containers at 180 ̊C for eight hours. Cation exchange capacities are determined for K+, Na+, Li+, Ca2+, and Sr2+; future studies demanding durable, highly specific composition …
Enhanced Tribological Properties Of Surfaces Patterned With Su8/Dlc Microstructures, Luke Osborn
Enhanced Tribological Properties Of Surfaces Patterned With Su8/Dlc Microstructures, Luke Osborn
Inquiry: The University of Arkansas Undergraduate Research Journal
In tribology (the study of friction, wear, and lubrication), it is known that micro-textured surfaces can reduce friction due to decreased contact area between two surfaces. The problem with many micro-textures, however, is their inability to withstand significant amounts of wear, thus limiting their potential uses and overall effectiveness. In this study, connected and isolated microstructures of SU8, a negative tone photoresist, coated with and without diamond-like carbon (DLC), were designed to investigate the effects of these microstructures and DLC coating on the tribological performance of a surface. Friction and wear studies were conducted using a tribometer; surface topography and …
Parallelizing Scale Invariant Feature Transform On A Distributed Memory Cluster, Stanislav Bobovych
Parallelizing Scale Invariant Feature Transform On A Distributed Memory Cluster, Stanislav Bobovych
Inquiry: The University of Arkansas Undergraduate Research Journal
Scale Invariant Feature Transform (SIFT) is a computer vision algorithm that is widely-used to extract features from images. We explored accelerating an existing implementation of this algorithm with message passing in order to analyze large data sets. We successfully tested two approaches to data decomposition in order to parallelize SIFT on a distributed memory cluster.
Design, Fabrication, And Testing Of An Electrospinning Apparatus For The Deposition Of Pmma Polymer For Biomedical Applications, Harsha Malshe
Design, Fabrication, And Testing Of An Electrospinning Apparatus For The Deposition Of Pmma Polymer For Biomedical Applications, Harsha Malshe
Inquiry: The University of Arkansas Undergraduate Research Journal
This paper describes the successful design and fabrication of a deposition system for synthesis and assembly of nanoscale and submicron sized fibers of poly(methylmethacrylate)(PMMA) polymer. To optimize the electrospinning deposition process, the distance between the needle and the electrically grounded substrate, the applied voltage, and the concentration of PMMA polymer in the solution were varied. PMMA fibers as small as 500 nanometers were observed using scanning electron microscopy (SEM). The chemical signature of PMMA was confirmed for best quality and retention of chemistry using Fourier Transformed Infrared spectroscopy (FT-IR). PMMA is a biocompatible polymer, and nanofibers of PMMA are key …
In-Vivo Testing Of Vertically Aligned Nanowire Implantable Titanium Electrodes In The Rattus Norvegicus Hippocampus, Lauren Kegley
In-Vivo Testing Of Vertically Aligned Nanowire Implantable Titanium Electrodes In The Rattus Norvegicus Hippocampus, Lauren Kegley
Inquiry: The University of Arkansas Undergraduate Research Journal
Miniaturized multielectrode arrays are MEMS devices that have found use as neural prosthetics (Neuro-MEMS). As implants, they can interface with neurons as sensors or actuators and help compensate for loss of sensory input, motor control, or cognitive functions. The microelectrodes studied here were developed in-house. They have a vertically aligned gold nanowire array and are mounted on a sturdy titanium needle with a fine gauge. Hence, the bill of materials and design characteristics encourage their use as a neural probe. For this study, a probe was tested in vivo for signal acquisition in the hippocampus of a Rattus Norvegicus (Sprague …
A Computational Model Of Breast Ducts, Jordan Greenlee
A Computational Model Of Breast Ducts, Jordan Greenlee
Inquiry: The University of Arkansas Undergraduate Research Journal
Ductal Carcinoma represents almost 75% of breast cancer. In this specific type of cancer. malignant cells in the breast ducts invade the surrounding healthy tissue. Almost all researchers who are investigating microwave modality in the area of breast cancer detection employ oversimplified models of the internal structure of the breast. Use of engineered or biologically inaccurate models can render inaccurate results. Therefore. a mathematical biological model was implemented in this work aiming to bridge the gap between physiologists and engineers. The result show that the proposed breast duct model has the capability of modeling the breast ducts of different kinds …
Factors Affecting The Spread Of A Bioterrorist Agent Throughout A Building, William A. Cantrell
Factors Affecting The Spread Of A Bioterrorist Agent Throughout A Building, William A. Cantrell
Inquiry: The University of Arkansas Undergraduate Research Journal
Bioterrorism has become a greater concern for Americans since the 2001 anthrax letters. Recent studies have explored the possibilities of biological attacks, and most deal with possible large-scale attacks. However, there is reason to believe that small-scale attacks are more likely. Even though there have been investigations of the postal delivery system and the spread of bioagents through mail, few if any studies have looked at attack on a single building and the resultant spread form room to room. One particular method of attacking a building would be a single-even release of an aerosol bioagent in the building. This paper …
Computational Modeling Of Oxidative Stress: An Analysis Of Nad(P)H Effects On Nitric Oxide And Superoxide During Hypertension, Aaron Strobel
Computational Modeling Of Oxidative Stress: An Analysis Of Nad(P)H Effects On Nitric Oxide And Superoxide During Hypertension, Aaron Strobel
Inquiry: The University of Arkansas Undergraduate Research Journal
Nitric oxide (NO) is inactivated in the human body when exposed to superoxide (02-). This reaction forms peroxynitrite (ONOO). Superoxide is produced in the cardiac system by several mechanisms, including NAD(P)H oxidase. Superoxide dismutase (SOD) breaks down superoxide into oxygen and hydrogen peroxide. This prevents superoxide from reacting with nitric oxide and allows normal function to take place. Superoxide and peroxynitrite are main contributors to vascular disease in the human body, in particular hypertension.
Improvement To The Data Logging Capability Of A Cough Monitoring System, Matthew Barlow
Improvement To The Data Logging Capability Of A Cough Monitoring System, Matthew Barlow
Inquiry: The University of Arkansas Undergraduate Research Journal
Data logging capability of a previously developed self contained cough recorder using an accelerometer as the sensing element is improved by using a secure digital memory card for later retrieval on a computer. Firmware is developed to enhance the functionality of the cough recorder. Existing libraries are modified for increased write rates. Increased writing speed allows 8-bit sampling at rates exceeding 8kHz, allowing for detailed time and frequency domain analysis. Additional features have also been developed to enable easy management of recordings, such as a file system compatibility with Microsoft Windows., and unique file names for each recording.
A Study Of The Impact Of Prognostic Errors On System Performance, Mauricio Carrasco
A Study Of The Impact Of Prognostic Errors On System Performance, Mauricio Carrasco
Inquiry: The University of Arkansas Undergraduate Research Journal
Condition-based maintenance is growing in popularity as a means of improving equipment maintenance efficiency. Whether it be the maintenance of an airplane, a computer system, or any type of physical system, the prognostic tools associated with condition-based maintenance are subject to statistical error. These errors can lead to unnecessary preventive maintenance due to underestimation of system remaining life and unnecessary system failures due to overestimation of system remaining life. What is not clear is if these statistical errors outweigh the benefits of a condition-based maintenance policy. This study attempts to address this concern through the evaluation and comparison of three …
Evaluation Of Rice Hulls As A Lignocellulosic Substitute In Wood Plastic Composites, P. Jack Bourne
Evaluation Of Rice Hulls As A Lignocellulosic Substitute In Wood Plastic Composites, P. Jack Bourne
Inquiry: The University of Arkansas Undergraduate Research Journal
Rising raw material costs and shortage of woody materials necessitate alternative sources for lignocellulosic material in wood plastic composites (WPC). This study was conducted to evaluate rice hull (RH), an agricultural residue, as a cellulosic substitute in WPC. Samples were fabricated with approximately 4% zinc stearate, 48% high-density polyethylene obtained from recycled plastics and 48% lignocellulosic material by mass. The composition of the lignocellulosic material was changed from 0 to 100% RH at 20% increments while the remainder was wood flour. The extruded sampled were tested for mechanical properties such as specific gravity, water absorption, linear coefficients of thermal expansion, …
Ultrafiltration Membrane Process For Pyrogen Removal In The Preparation Of Water For Injection (Wfi), Thet N. Soe
Ultrafiltration Membrane Process For Pyrogen Removal In The Preparation Of Water For Injection (Wfi), Thet N. Soe
Inquiry: The University of Arkansas Undergraduate Research Journal
An artificial kidney process based on ultrafiltration (called hemodiafiltration) more effectively removes blood toxins, particularly those of higher molecular weight, than conventional dialysis. In hemodiafiltration, replacement liquid must be added directly to the patient's blood to replace liquid filtered out of the blood in the ultrafiltration cartridge. This replacement liquid is made up of' "water for injection" (WFI) and other components such as salts and glucose. WFI is produced either by distillation or reverse osmosis and has a cost of $1.00 per liter. A patient with kidney problems would require three hemodiafiltration treatments per week, each requiring 70-80 liters of …
Use Of Calcium Hypochlorite As A Sanitizer For Seeds Used For Sprouting: Task #2; Impact: Improved Alfalfa Decontamination Technologies, Emily Damron, Carrie Klein, Melissa Leach, Jordan Mourot, Tom Murphy, Amy Seamans, Ryan Wilson
Use Of Calcium Hypochlorite As A Sanitizer For Seeds Used For Sprouting: Task #2; Impact: Improved Alfalfa Decontamination Technologies, Emily Damron, Carrie Klein, Melissa Leach, Jordan Mourot, Tom Murphy, Amy Seamans, Ryan Wilson
Inquiry: The University of Arkansas Undergraduate Research Journal
Consumption of raw or lightly cooked alfalfa sprouts has been a concern of the U.S. Food and Drug Administration (FDA) in recent years due to connections between sprouts and foodborne illnesses. Researchers have identified, contaminated seeds as the primary source of alfalfa sprouts contamination. Contamination of alfalfa seeds can originate in the field, harvesting, storing, or sprouting. Two pathogens of particular concern on alfalfa seeds are Escherichia coli 0157:H7 (E. coli) and Salmonella. These pathogens are capable of producing biofilms that provide protection for individual cells and allow for survival in otherwise hostile environments, including some disinfectant washes. Other factors …
A Comparative Evaluation Of .Net Remoting And Java Rmi, Taneem Ibrahim
A Comparative Evaluation Of .Net Remoting And Java Rmi, Taneem Ibrahim
Inquiry: The University of Arkansas Undergraduate Research Journal
Distributed application technologies such as Micrososoft.NET Remoting, and Java Remote Method Invocation (RMI) have evolved over many years to keep up with the constantly increasing requirements of the enterprise. In the broadest sense, a distributed application is one in which the application processing is divided among two or more machines. Distributed middleware technologies have made significant progress over the last decade. Although Remoting and RMI are the two of most popular contemporary middleware technologies, little literature exists that compares them. In this paper, we study the issues involved in designing a distributed system using Java RMI and Microsoft.NET Remoting. In …
Parameter Extraction Software For Silicon Carbide Schottky, Merged Pin Schottky And Pin Power Diode Models, Edgar Cilio
Parameter Extraction Software For Silicon Carbide Schottky, Merged Pin Schottky And Pin Power Diode Models, Edgar Cilio
Inquiry: The University of Arkansas Undergraduate Research Journal
A software program for on-state parameter extraction is presented for the realization of a high quality model for SiC Schottky, Merged PiN Schottky, and PiN Power diodes based on McNutt and Mantooth's Comprehensive SiC Diode model [ 1 ].
Investigation On How To Improve Latent Semantic Analysis Performance, Thao Doan
Investigation On How To Improve Latent Semantic Analysis Performance, Thao Doan
Inquiry: The University of Arkansas Undergraduate Research Journal
Latent Semantic Analysis (LSA) is a matching technique capable of recognizing the semantic relationships of data that ordinary techniques such as string matching cannot. This is especially valuable for data integration applications, like those of Acxiom, where data items are usually related by context, rather than in a literal match. Even though it has been shown that LSA is 30% more effective in finding and ranking relevant pieces of information than existing string-by-string matching techniques (Deerwester et al., 1990; Dumais, 1995), the performance of the LSA seems to be affected by the presence of shared words, or “noise”, in data. …
Extraction Of Silymarin Compounds From Milk Thistle (Silybum Marianum) Seed Using Hot, Liquid Water As The Solvent, J.F. Alvarez Barreto
Extraction Of Silymarin Compounds From Milk Thistle (Silybum Marianum) Seed Using Hot, Liquid Water As The Solvent, J.F. Alvarez Barreto
Inquiry: The University of Arkansas Undergraduate Research Journal
High value specialty chemicals are usually obtained from natural products by extracting with generally regarded as safe (GRAS) solvents. Because organic solvents are quite often used, high operating and disposal costs often occur. When compared to traditional solvents, water can be viewed as an interesting alternative because of its low operating and disposal costs. Milk thistle contains compounds (taxifolin, silychristin, silydianin, silybinin A and silybinin B) that display hepatoxic protection properties. This paper examines the batch extraction of silymarin compounds from milk thistle seed meal in 50'C, 70'C, 85'C and 100'C water as a function of time. For taxifolin, silychristin, …
The Need For Pfc Abatement In Semiconductor Manufacturing, Mohsen Manesh, Brian Kendrick
The Need For Pfc Abatement In Semiconductor Manufacturing, Mohsen Manesh, Brian Kendrick
Inquiry: The University of Arkansas Undergraduate Research Journal
Perfluorocompounds (PFCs) are highly stable chemical compounds used in two integral steps of semiconductor manufacturing: chemical vapor deposition (CVD) chambers and etch chambers. Unfortunately, PFCs are also greenhouse gases linked to global warming. This, combined with their long atmospheric lifetimes gives them global warming potentials much higher than C02 the principal greenhouse gas. In a series of voluntary agreements with the United States and other national governments, the worldwide semiconductor industry has set a goal of reducing PFC emissions to 90% of their 1995 levels. To reach this goal, researchers have explored four main methods of reduction: substitution of PFCs, …
A Method Of Implementing The Interleaver In 3g Wireless Communication Systems For Randomization Of Burst Errors, Eric Duquette
A Method Of Implementing The Interleaver In 3g Wireless Communication Systems For Randomization Of Burst Errors, Eric Duquette
Inquiry: The University of Arkansas Undergraduate Research Journal
In less than a year or two, third generation ( 3G) wireless communication systems will be replacing the currently existing second generation (2G) wireless systems and be used worldwide. The 3G systems will have a higher data transfer capacity, which allows for simultaneous data, voice, and video transfer (e.g., multimedia applications) while most of 2G systems only allow for low-rate data and voice transfer. The wireless communications industry has set standards for 3G, which detail various operations of the technology. It should be noted that the 3G standards outline only the different operations and not the processes for the production …
Analysis Of Wireless Networking On The University Of Arkansas Campus, Julia Lincoln
Analysis Of Wireless Networking On The University Of Arkansas Campus, Julia Lincoln
Inquiry: The University of Arkansas Undergraduate Research Journal
Wireless communication has already begun to change the way business and research is done today. Development of the wireless network for digital cellular phone has already improved the area of voice communications. The area of portable and mobile connectivity for computers and other devices is beginning to emerge. The research analyzes and compares a few of these wireless networks. Physical aspects such as range, interference factors, and frequency capabilities and restrictions are assessed. Capacity analysis including round trip times, latency, and throughput are done as well. Issues of authentication and addressing protocols are researched to determine optimal performance and convenience …