Engineering Commons^™

Si Implant-Assisted Ohmic Contacts To Gan, Cuong Nguyen, Pankaj Shah, Edward Leong, Michael Derenge, Kenneth Jones

United States Army: Publications

The contact resistance, ρ_C, was measured for the traditional Ti/Al/Ni/Au Ohmic contact for samples implanted with Si to >10²⁰ cm^-3 and annealed at 1100, 1150, 1200, or 1250°C for 2, 5 or 10 min using an AlN annealing cap. These results are compared with those for samples annealed in the same way, but were not implanted. The as-grown samples were doped to 3.56 × 10¹⁷ or 6.67 × 10¹⁶ cm^-3 or were unintentionally (UI) doped. In almost all cases, ρ_C for the implanted sample was lower, and a record low ρ_{C …}

Characterization Of Nanometer Scale Compositionally Inhomogeneous Algan Active Regions On Bulk Aln Substrates, A. V. Sampath, G. A. Garrett, E. D. Readinger, R. W. Enck, H. Shen, M. Wraback, J. R. Grandusky, L. J. Schowalter

United States Army: Publications

The optical and structural properties of AlGaN active regions containing nanoscale compositional inhomogeneities (NCI) grown on low dislocation density bulk AlN substrates are reported. These substrates are found to improve the internal quantum efficiency and structural quality of NCI-AlGaN active regions for high Al content alloys, as well as the interfaces of the NCI with the surrounding wider bandgap matrix, as manifested in the absence of any significant long decay component of the low temperature radiative lifetime, which is well characterized by a single exponential photoluminescence decay with a 330 ps time constant. However, room temperature results indicate that non-radiative …

Impact Of Woven Fabric: Experiments And Mesostructure-Based Continuum-Level Simulations, Ethan M. Parsons, Tusit Weerasooriya, Sai Sarva, Simona Socrate

United States Army: Publications

Woven fabric is an increasingly important component of many defense and commercial systems, including deployable structures, restraint systems, numerous forms of protective armor, and a variety of structural applications where it serves as the reinforcement phase of composite materials. With the prevalence of these systems and the desire to explore new applications, acomprehensive, computationally efficient model for the deformation of woven fabrics is needed. However, modeling woven fabrics is difficult due, inparticular, to the need to simulate the response both at the scale of the entire fabric and at the meso-level, the scale of the yarns that compose the weave. …

Chemisorption Of A Thiol-Functionalized Ruthenium Dye On Zinc Oxide Nanoparticles: Implications For Dye-Sensitized Solar Cells, Jagdeep Singh, Jisun Im, James E. Whitten, Jason W. Soares, Diane M. Steeves

United States Army: Publications

ZnO is an alternative to TiO₂-based dye-sensitized solar cells (DSSCs). Adsorption of cis-rutheniumbis [2,2'-bipyridine]-bis[4-thiopyridine] onto ZnO nanorods has been studied using X-ray and ultraviolet photoelectron spectroscopies (XPS and UPS). XPS indicates chemisorption with a surface density of ca. 1 × 10¹⁵ molecules/cm², confirming the possibility of using thiol-terminated dyes for ZnO-based DSSC devices. The energy level diagram, based on UPS and absorbance spectroscopy, indicates that the LUMO of this dye is lower in energy than the ZnO conduction band edge, providing minimal enthalpic driving force for photovoltaic electron injection. However, optimization of thiol-functionalized Ru …

Dual-Stage Sugar Substitution In Strawberries With A Stevia-Based Sweetener, Juan Garcia-Noguera, Curtis L. Weller, Francisca I. P. Oliveira, Sueli Rodrigues, Fabiano A. N. Fernandes

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The present study introduces and analyzes a new process denominated dual-stage sugar substitution (D3S). This process aims to induce sugar substitution in strawberries. In a first stage, high-calorie sugars (sucrose, fructose and glucose) are partially removed from the fruit samples and in a second stage, low-calorie sugar (stevioside and rebaudioside) is incorporated to the fruit to maintain its sweetness. The process was evaluated by studying the use of ultrasound application in one or both stages of the D3S process. Best performance of the process was obtained by subjecting the fruit samples to ultrasound in the sugar removal stage followed by …

Status And Trend Of Cottonwood Forests Along The Missouri River, Mark D. Dixon, W. Carter Johnson, Michael L. Scott, Daniel Bowen

United States Army Corps of Engineers, Omaha District

From 2007-2009, we studied the current (2006) and historic (1892, mid-1950s) extent, current age distribution, and plant species composition of plains cottonwood (Populus deltoides) and non-cottonwood riparian stands along eight study segments of the Missouri River between Fort Benton, Montana and Kansas City Missouri, covering 930 river miles (1500 km) or over 1/3 of the river's length. These segments included all of the unchannelized and unimpounded segments below Fort Benton, as well as portions of two impounded and one channelized segment. Based on GIS analyses of historic maps and aerial photography, the combined area of forests, woodlands, and …

Geochemical Investigations Of Metals Release From Submerged Coal Fly Ash Using Extended Elutriate Tests, A. J. Bednar, M. A. Chappell, J. M. Seiter, J. K. Stanley, D. E. Averett, W. T. Jones, B. A. Pettway, A. J. Kennedy, S. H. Hendrix, J. A. Steevens

United States Army: Publications

A storage pond dike failure occurred at the Tennessee Valley Authority Kingston Fossil Plant that resulted in the release of over 3.8 million cubic meters (5 million cubic yards) of fly ash. Approximately half of this material deposited in the main channel of the Emory River, 3.5 km upstream of the confluence of the Emory and Clinch Rivers, Tennessee, USA. Remediation efforts to date have focused on targeted removal of material from the channel through hydraulic dredging, as well as mechanical excavation in some areas. The agitation of the submerged fly ash during hydraulic dredging introduces river water into the …

Study Of Strawberry Flavored Milk Under Pulsed Electric Field Processing, Daniela Bermúdez-Aguirre, Jaime A. Yáñez, C. Patrick Dunne, Neal M. Davies, Gustavo V. Barbosa-Cánovas

United States Army: Publications

Few studies exist on flavored milk processed by pulsed electric fields (PEF). The main concern is product stability. This study aimed to analyze the degradation of coloring agent Allura Red in strawberry milk under PEF. Four systems were tested containing Allura Red: two commercial milks and two model systems. PEF conditions were 40 kV/cm, 48 pulses (2.5 μs), and 55 °C; coloring agent was quantified via RP-HPLC. After processing, only minor changes were observed in color, Allura Red concentration, and pH. During storage (32 d) at refrigerated conditions (4 °C) commercial samples maintained pH above 6. Model systems dropped below …

Nontuberculous Mycobacterium Infection In A Burn Icu Patient, Joseph M. Boyer, Peter J. Blatz, Kevin S. Akers, Jason F. Okulicz, Kevin K. Chung, Evan M. Rentz, Duane R. Hospenthal, Clinton K. Murray

United States Army: Publications

Infection is a leading cause of mortality in burn patients, typically due to bacterial pathogens such as Staphylococcus aureus and Pseudomonas aeruginosa, less commonly fungi, and possibly viruses. In non-burn patients with underlying pulmonary or cutaneous disease, nontuberculous mycobacteria (NTM) have become an increasingly recognized cause of infection, especially in patients who are immunocompromised. Patients with severe burns might have higher rates of NTM infections due to inherent risks associated with the burn injury: compromised skin integrity, immunocompromised state, inhalation injury, and frequent use of indwelling vascular catheters. To date there have been no reports describing the incidence of …

Acute Caffeine Consumption Enhances The Executive Control Of Visual Attention In Habitual Consumers, Tad T. Brunyé, Caroline R. Mahoney, Harris R. Lieberman, Grace E. Giles, Holly A. Taylor

United States Army: Publications

Recent work suggests that a dose of 200–400 mg caffeine can enhance both vigilance and the executive control of visual attention in individuals with low caffeine consumption profiles. The present study seeks to determine whether individuals with relatively high caffeine consumption profiles would show similar advantages. To this end, we examined the effects of four caffeine doses (0 mg, 100 mg, 200 mg, 400 mg) on low- and high-level visual attention in individuals with high consumption profiles (n = 36), in a double-blind study using a repeated measures design. Results from the Attention Network Test indicated that caffeine enhanced both …

Genomics And Proteomics In Chemical Warfare Agent Research: Recent Studies And Future Applications, Patrick A. Everly, James F. Dillman

United States Army: Publications

Medical research on the effects of chemical warfare agents (CWAs) has been ongoing for nearly 100 years, yet these agents continue to pose a serious threat to deployed military forces and civilian populations. CWAs are extremely toxic, relatively inexpensive, and easy to produce, making them a legitimate weapon of choice for terrorist organizations. While the mechanisms of action for manyCWAshave been known for years, questions about their molecular effects following acute and chronic exposure remain largely unanswered. Global approaches that can pinpoint which cellular pathways are altered in response to CWAs and characterize long-term toxicity have not been widely used. …

The Effects Of Bleedarrest, Celox, And Traumadex On Hemorrhage Control In A Porcine Model, Brian Gegel, James Burgert, Brian Cooley, Jacob Macgregor, Jules Myers, Sean Calder, Ralph Luellen, Michael Loughren, Don Johnson

United States Army: Publications

Background

Hemorrhage is the second leading cause of death in civilian trauma and the leading cause of preventable death in military trauma. The purpose
of this study was to examine the effectiveness of three hemostatic agents: BleedArrest, TraumaDex, and Celox.

Materials and Methods

This was a prospective, experimental study using male Yorkshire swine. The pigs (n = 5 per group) were randomly assigned to one of the following: BleedArrest, TraumaDex, Celox, or control. To simulate a trauma injury, the investigators generated a complex groin injury with transection of the femoral artery and vein in all pigs. After 1 min of …

Effects Of The Heet Garment In The Prevention Of Hypothermia In A Porcine Model, Don Johnson, Brian Gegel, James Burgert, Geoffrey W, Duncklee, Ricci R. Robinson, Eric J. Lewis, Paul M. Crum, William Kuhns, Daniel Moore, Scott O'Brien, Joel Elliott, Jason Washington, John Boyle, Dale Seigler

United States Army: Publications

Background

Hypothermia is a common battlefield trauma occurrence. This study compared the effectiveness of the hypothermia, environmental, exposure, and trauma (HEET) garment (Trident Industries, Beaufort, SC) with and without thermal inserts with a control group of two wool blankets in the prevention of hypothermia in a treated hypovolemic porcine model.

Materials and methods

Five female swine (Sus scrofa-Yorkshire cross) were assigned to each of three
groups: HEET with thermal inserts (n=5); HEET without thermal inserts (n=5); or control (n=5). After the animals were anesthetized and stabilized for 30min, the swine were hemorrhaged to a mean arterial pressure (MAP) of 30mm …

Morphology Control Of Tungsten Nanorods Grown By Glancing Angle Rf Magnetron Sputtering Under Variable Argon Pressure And Flow Rate, Khedir R. Khedir, Ganesh K. Kannarpady, Hidetaka Ishihara, Justin Woo, Charles Ryerson, Alexandru S. Biris

United States Army: Publications

Morphologically novel tungsten nanorods (WNRs) with the co-existence of two crystalline phases, α-W (thermodynamically stable) and β-W, were fabricated by glancing angle RF magnetron sputtering technique under various Ar pressures and flow rates. For these nanorods, a significant variation in their morphology and surface roughness was observed. These structures could be useful in a wide range of applications such as field emission, robust superhydrophobic coatings, energy, and medicine.

Inflammatory Effects Of Inhaled Sulfur Mustard In Rat Lung, Rama Malaviya, Vasanthi R. Sunil, Jessica Cervelli, Dana R. Anderson, Wesley W. Holmes, Michele L. Conti, Ronald E. Gordon, Jeffrey D. Laskin, Debra L. Laskin

United States Army: Publications

Inhalation of sulfur mustard (SM), a bifunctional alkylating agent that causes severe lung damage, is a significant threat to both military and civilian populations. The mechanisms mediating its cytotoxic effects are unknown and were investigated in the present studies. Male rats Crl:CD(SD) were anesthetized, and then intratracheally intubated and exposed to 0.7–1.4 mg/kg SM by vapor inhalation. Animals were euthanized 6, 24, 48 h or 7 days post-exposure and bronchoalveolar lavage fluid (BAL) and lung tissue collected. Exposure of rats to SM resulted in rapid pulmonary toxicity, including focal ulceration and detachment of the trachea and bronchial epithelia from underlying …

Inhibition Of Hiv-1 Infection Of Peripheral Blood Mononuclear Cells By A Monoclonal Antibody That Binds To Phosphoinositides And Induces Secretion Of Β-Chemokines, Gary R. Matyas, Lindsay Wieczorek, Divya Bensal, Agnes-Laurence Chenine, Eric Saunders-Buell, Sodsai Tovanabutra, Jerome H. Kim, Victoria Polonis, Carl R. Alving

United States Army: Publications

A murine IgG mAb, WR321, selected for the ability to bind to phosphatidylinositol-4-phosphate and phosphatidylinositol-4, 5-bisphosphate, but an inability to bind to any of 17 other lipids, including phosphatidylinositol, was examined as a probe for studying interactions of HIV-1 with primary human peripheral blood mononuclear cells. The WR321 mAb broadly neutralized CCR5-tropic strains of HIV-1 to prevent infection of the cells. The mAb also exhibited direct interaction with cells in the culture, resulting in secretion of chemokines that interfered with the interaction of HIV-1 virions with CCR5, the coreceptor for HIV-1 on the susceptible cells, leading to inhibition of infection …

Multiscale Modeling Of The Impact Of Textile Fabrics Based On Hybrid Element Analysis, Gaurav Nilakantan, Michael Keefe, Travis A. Bogetti, John W. Gillespie Jr.

United States Army: Publications

In this work, a multi scale modeling approach has been developed to simulate the impact of woven fabrics using a finite element (FE) analysis. A yarn level of resolution is used in the model. This approach, referred to as the hybrid element analysis (HEA) is based on decreasing the complexity of the finite element model with distance away from the impact zone based on the multiscale nature of the fabric architecture and the physics of the impact event. Solid elements are used to discretize the yarns around the impact region, which transition to shell elements in the surrounding region. A …

Shrapnel-Induced Mandibular Hypomobility, David E. Palo, Paul J. Warden

United States Army: Publications

Mandibular hypomobility can develop from direct injury to, or as a result of disorders affecting, the supporting structures of the temporomandibular joint. This can be subdivided into intra-articular and extraarticular processes. Ankylosis is commonly associated with trauma (31% to 98%), followed by infections (10% to 49%) and systemic disease (10%). Temporomandibular joint ankylosis is an intra-articular process characterized by fibrous, fibro-osseous, or osseous obliteration of the joint space. Pseudoankylosis involves extracapsular causes of restricted jaw motion that include, but are not limited to, coronoid-zygomatic fusion, coronoid hypertrophy, and muscular fibrosis. Shrapnel injuries can be as devastating as high-velocity gunshot wounds, …

Biological Transformation Pathways Of 2,4-Dinitro Anisole And N-Methyl Paranitro Aniline In Anaerobic Fluidized-Bed Bioreactors, William E. Platten Iii, David Bailey, Makram T. Suidan, Stephen W. Maloney

United States Army: Publications

The US Army is evaluating new, insensitive explosives to produce safer munitions. Two potential new components are 2,4-dinitro anisole (DNAN) and N-methyl paranitro aniline (MNA), which would eventually make their way to waste streams generated in the production and handling of new munitions. The effectiveness of anaerobic fluidized-bed bioreactors (AFBB) was studied for treatment and transformation of these two new chemical components in munitions. Each compound was fed into a separate reactor and monitored for removal and transformation, using ethanol as the electron donor. The results show that both were degradable using the AFBB system. DNAN was found to transform …

Characterization Of Silver Nanoparticles Using Flow-Field Flow Fractionation Interfaced To Inductively Coupled Plasma Mass Spectrometry, A. R. Poda, A. J. Bednar, A. Harmon, M. Hull, D. M. Mitrano, J. F. Ranville, J. Steevens

United States Army: Publications

The ability to detect and identify the physiochemical form of contaminants in the environment is important for degradation, fate and transport, and toxicity studies. This is particularly true of nanomaterials that exist as discrete particles rather than dissolved or sorbed contaminant molecules in the environment. Nanoparticles will tend to agglomerate or dissolve, based on solution chemistry, which will drastically affect their environmental properties. The current study investigates the use of field flow fractionation (FFF) interfaced to inductively coupled plasma-mass spectrometry(ICPMS) as a sensitive and selective method for detection and characterization of silver nanoparticles. Transmission electron microscopy (TEM) is used to …

Current Us Military Operations And Implications For Military Surgical Training, Joshua A. Tyler, Kevin S. Clive, Christopher E. White, Alec C. Beekley, Lorne H. Blackbourne

United States Army: Publications

BACKGROUND:

Since 2001, US military surgeons have deployed frequently, with many surgeons deploying within 1 year of graduating residency. The purpose of this study was to evaluate readiness of recent graduates to manage combat-related injuries and to make recommendations for improvements in training military surgeons.

STUDY DESIGN:

We reviewed casualties treated at the 31^st Combat Support Hospital in Baghdad from December 2003 to November 2004.We identified 3,426 wounded patients; of these, 2,648 (77.3%) required an operative procedure. There were 2,788 patients (81.4%) who sustained penetrating injuries. The most common procedures performed were debridement of wounds (39%), skeletal fixation (14.7%), …

Monotonic And Cyclic Short Beam Shear Response Of 3d Woven Composites, T. R. Walter, G. Subhash, University Of Florida, C. F. Yen

United States Army: Publications

Monotonic, multi-step and cyclic short beam shear tests were conducted on 2D and 3D woven composites. The test results were used to determine the effect of z-yarns on the inter-laminar shear strength as well as the multi-loading behavior. The presence of z-yarns was found to affect not only the inter-laminar shear strength of the composite but also the behavior of the composite beyond the elastic limit. Microscopic examination of the damaged specimens revealed large delamination cracks in 2D woven composites while delamination cracks were hindered by z-yarns in 3D composites. This crack arrest phenomena resulted in a reduction in inter-laminar …

Evaluation Of Biological Cell Properties Using Dynamic Indentation Measurement, Guoxin Cao, Namas Chandra

Department of Engineering Mechanics: Faculty Publications

Viscoelastic mechanical properties of biological cells are commonly measured using atomic force microscope (AFM) dynamic indentation with spherical tips. A semiempirical analysis based on numerical simulation is built to determine the cell mechanical properties. It is shown that the existing analysis cannot reflect the accurate values of cell elastic/dynamic modulus due to the effects of substrate, indenter tip size, and cell size. Among these factors, substrate not only increases the true contact radius but also interferes the indentation stress field, which can cause the overestimation of cell moduli. Typically, the substrate effect is much stronger than the other two influences …

Luminescence Enhancement Of Cdte Nanostructures In Laf3:Ce/Cdte Nanocomposites, Mingzhen Yao, Xing Zhang, Lun Ma, Wei Chen, Alan G. Joly, Jinsong Huang, Qingwu Wang

Department of Mechanical and Materials Engineering: Faculty Publications

Radiation detection demands new scintillators with high quantum efficiency, high energy resolution, and short luminescence lifetimes. Nanocomposites consisting of quantum dots and Ce³⁺ doped nanophosphors may be able to meet these requirements. Here, we report the luminescence enhancement of LaF₃:Ce/CdTe nanocomposites which were synthesized by a wet chemistry method. CdTe quantum dots in LaF₃:Ce/CdTe nanocomposites are converted into nanowires, while in LaF₃ /CdTe nanocomposites no such conversion is observed. As a result, the CdTe luminescence in LaF₃:Ce/CdTe nanocomposites is enhanced about five times, while in LaF₃ /CdTe nanocomposites no enhancement was …

Directional Annealing-Induced Texture In Melt-Spun (Sm12Co88)99Nb1 Alloy, Tanjore V. Jayaraman, P. Rogge, Jeffrey E. Shield

Department of Mechanical and Materials Engineering: Faculty Publications

Developing texture in nanocrystalline permanent magnet alloys is of significant importance. Directional annealing is shown to produce texture in the permanent magnet alloy (Sm₁₂Co₈₈)₉₉Nb₁. Melt spinning produced isotropic grain structures of the hard magnetic metastable SmCo₇ phase, with grain sizes of ∼300 nm. Conventional annealing of melt-spun (Sm₁₂Co₈₈)₉₉Nb₁ alloy produced Sm₂Co₁₇ phase with random crystallographic orientation. Directional annealing of melt-spun (Sm₁₂Co₈₈)₉₉Nb₁ alloy, with appropriate combinations of annealing temperature and translational velocity, produced Sm_{2 …}

Linearized Theory Of Peridynamic States, S. A. Silling

United States Department of Energy: Publications

A state-based peridynamic material model describes internal forces acting on a point in terms of the collective deformation of all the material within a neighborhood of the point. In this paper, the response of a state-based peridynamic material is investigated for a small deformation superposed on a large deformation. The appropriate notion of a small deformation restricts the relative displacement between points, but it does not involve the deformation gradient (which would be undefined on a crack). The material properties that govern the linearized material response are expressed in terms of a new quantity called the modulus state. This determines …

Nebraska Statewide Wind Integration Study: Executive Summary April 2008 – January 2010, Enernex Corporation Knoxville, Tennessee, Ventyx Atlanta, Georgia, Nebraska Power Association Lincoln, Nebraska

United States Department of Energy: Publications

Wind generation is a source of electric energy that, in sufficient quantity, can cause concern for the operation of the bulk power system because of the variability and uncertainty of the wind. Most short-term planning and operational functions supporting the electric power grid are centered on supply resources that have capacity attributes – i.e. they can be dispatched (controlled up and down) to a specified power level for a specified period of time. The need to maintain very high levels of system reliability reinforces the preference in operations toward resources having capacity attributes. Wind generation usually has relatively low capacity …

Microbial And Mineralogical Characterizations Of Soils Collected From The Deep Biosphere Of The Former Homestake Gold Mine, South Dakota, Gurdeep Rastogi, Shariff Osman, Ravi K. Kukkadapu, Mark Engelhard, Parag A. Vaishampayan, Gary L. Andersen, Rajesh K. Sani

United States Department of Energy: Publications

A microbial census on deep biosphere (1.34 km depth) microbial communities was performed in two soil samples collected from the Ross and number 6Winze sites of the former Homestake gold mine, Lead, South Dakota using high-density 16S microarrays (PhyloChip). Soil mineralogical characterization was carried out using X-ray diffraction, X-ray photoelectron, and Mössbauer spectroscopic techniques which demonstrated silicates and iron minerals (phyllosilicates and clays) in both samples. Microarray data revealed extensive bacterial diversity in soils and detected the largest number of taxa in Proteobacteria phylum followed by Firmicutes and Actinobacteria. The archael communities in the deep gold mine environments were …

Microbial Reduction Of Uranium Under Iron- And Sulfate-Reducing Conditions: Effect Of Amended Goethite On Microbial Community Composition And Dynamics, H.S. Moon, L. Mcguinness, Ravi K. Kukkadapu, A.D. Peacock, John Komlos, L.J. Kerkhof, P.E. Long, Peter R. Jaffe

United States Department of Energy: Publications

There is a growing need for a better understanding of the biogeochemical dynamics involved in microbial U(VI) reduction due to an increasing interest in using biostimulation via electron donor addition as a means to remediate uranium contaminated sites. U (VI) reduction has been observed to be maximized during iron-reducing conditions and to decrease upon commencement of sulfate-reducing conditions. There are many unknowns regarding the impact of iron/sulfate biogeochemistry on U(VI) reduction. This includes Fe(III) availability as well as the microbial community changes, including the activity of iron-reducers during the uranium biostimulation period even after sulfate reduction becomes dominant. Column experiments …

Confinement Resonances In Photoionization Of Xe@C+60, A. L. D. Kilcoyne, A. Aguilar, A. Muller, S. Schippers, C. Cisneros, G. Alna’Washi, N. B. Aryal, K. K. Baral, D. A. Esteves, C. M. Thomas, R. A. Phaneuf

United States Department of Energy: Publications

Experimental evidence is presented for confinement resonances associated with photoabsorption by a Xe atom in a C₆₀ cage. The giant 4d resonance in photoionization of Xe is predicted to be redistributed into four components due to multipath interference of photoelectron waves reflected by the cage. The measurements were made in the photon energy range 60–150 eV by merging a beam of synchrotron radiation with a mass/charge selected Xe@C⁺₆₀ ion beam. The phenomenon was observed in the Xe@C³⁺₅₈ product ion channel.