Engineering Commons^™

Fracture Analysis Of Kevlar-49/Epoxy And E-Glass/Epoxy Doublers For Reinforcement Of Cracked Aluminum Plates, Ananth Ram Mahanth Kasavajhala, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

Adhesively bonded composite patch repair is an efficient means to regain load carrying capacity, alleviate the crack growth, and improve the service life of the damaged structure. In this paper, three dimensional finite element models are developed to ex­amine the fracture behavior of a single edge V-notched Aluminum plate repaired with Kevlar-49/epoxy or e-glass/epoxy pre-preg patches on both sides. Contour integral method was used for evaluating the stress intensity factor (SIF), an indicator of the crack stability. The load transfer mechanisms, stress distribution, damage variable (D), and crack mouth opening displacement (CMOD), were also presented to estimate the …

Bacterial Killing By Dry Metallic Copper Surfaces, Christophe Espírito Santo, Ee Wen Lam, Christian Elowsky, Davide Quaranta, Dylan W. Domaille, Christopher J. Chang, Gregor Grass

Nebraska Center for Biotechnology: Faculty and Staff Publications

Metallic copper surfaces rapidly and efficiently kill bacteria. Cells exposed to copper surfaces accumulated large amounts of copper ions, and this copper uptake was faster from dry copper than from moist copper. Cells suffered extensive membrane damage within minutes of exposure to dry copper. Further, cells removed from copper showed loss of cell integrity. Acute contact with metallic copper surfaces did not result in increased mutation rates or DNA lesions. These findings are important first steps for revealing the molecular sensitive targets in cells lethally challenged by exposure to copper surfaces and provide a scientific explanation for the use of …

Nano-Particle/Quantum Dot Based Optical Dode, Dennis R. Alexander, John C. Bruce, Craig A. Zuhlke, Brandon E. Koch, Jitender S. Deogun, Haitham S. Hamza

Department of Electrical and Computer Engineering: Faculty Publications

A particle based optical diode having at least two cavities or at least two regions of a single cavity, wherein the regions contain different types of particles.

Developing Deterioration Models For Nebraska Bridges, George Morcous Ph.D., Afshin Hatami Ph.D.

Mid-America Transportation Center: Final Reports and Technical Briefs

Nebraska Bridge Management System (NBMS) was developed in 1999 to assist in optimizing budget allocation for the maintenance, rehabilitation and replacement needs of highway bridges. This requires the prediction of bridge deterioration to calculate life-cycle costs. At the meantime, the approach adopted to predict the deterioration of bridge components is based on national average deterioration rates, which are one drop in the deck condition rating every eight years and one drop in the superstructure and substructure condition rating every ten years. This approach does not account for the impact of traffic volume, structure and material type, and environment impacts, in …

Crash Analysis Of I-64 Closure In St. Louis County, Ghulam H. Bham Ph.D., Uday R.R Manepalli

Mid-America Transportation Center: Final Reports and Technical Briefs

On January 2, 2008, the Missouri Department of Transportation (MoDOT) closed significant portions of Missouri Interstate 64 (I-64) in St. Louis County for reconstruction. During the planning stages of this project, the proposal to close all lanes of I-64 was met with public concern regarding the possible safety risks associated with diverting I-64 traffic to adjacent roadways. A specific concern was the possibility of increased crash rates on roads designated to receive I-64 traffic flow. The following research was conducted to assess the actual outcomes related to these concerns. Crash analyses and crash rate analysis of 2008 and 2009 crash …

Performance Measures Of Warm Asphalt Mixtures For Safe And Reliable Freight Transportation Phase Ii: Evaluation Of Friction And Raveling Characteristics Of Warm Mix Asphalt Mixtures With Anti-Stripping Agents, Hosin David Lee Ph.D., P.E., Yongjoo Thomas Kim Ph.D.

Mid-America Transportation Center: Final Reports and Technical Briefs

The viscosity of asphalt decreased significantly when 0.5% of WMA additive was added,but it remained relatively steady as the dosage rate increased up to 3.0%. The reduction pattern in viscosity as the dosage rate increases was similar for both CECABASE RT® and LEADCAP at all test temperatures of 120°C,125°C, 130°C and 135 °C and a similar pattern was observed for both Sasobit® and Rediset. Based on the ABCD test device, the virgin asphalt binder PG 64-34 cracked at -51.0°C and the PG 64-28 cracked at -41.3°C. As the WMA additives were increased from 0.5%to 3.0%, the cracking temperatures increased slightly,but …

Assessing The Damage Potential In Pretensioned Bridges Caused By Increased Truck Loads Due To Freight Moments (Phase Ii), Robert J. Peterman Ph.D., P.E., Steven F. Hammerschmidt M.S.C.E.

Mid-America Transportation Center: Final Reports and Technical Briefs

With aging and deterioration of bridges, evaluation of existing conditions of their structural elements becomes vital to engineers and public officials when deciding how to repair or replace the structures. The ability to obtain necessary information on these conditions is often expensive and time consuming, especially for concrete bridges where the reinforcement is not available for inspection. Employing the surface-strain relief method could allow for accurate evaluation of aged or damaged prestressed members. The surface-strain relief method was developed to measure initial or pre-existing strains in a concrete member. It involves relieving the strain in the member and measuring the …

Effectiveness Study On Temporary Pavement Marking Removals Methods, Dr. Yong Cho, Dr. Jae-Ho Pyeon, Koudous Kabassi

Mid-America Transportation Center: Final Reports and Technical Briefs

This study was conducted to identify effective temporary marking removal methods and procedures on concrete and asphalt pavements. Pavement markings provide guidance to road travelers and can lead to accidents when not properly removed. Current state guidelines on removal do not provide clear and objective methods of measurement. After testing the most common removal methods, this research concluded that removing markings by chemical was not only cost efficient, result-oriented, and effective compared to other methods, but it was also safe to the environment and road users. Finally, a baseline of measurements was developed by the research team for this project, …

Meeting Reports: Research On Coupled Human And Natural Systems (Chans): Approach, Challenges, And Strategies, Marina Alberti, Heidi Asbjornsen, Lawrence A. Baker, Nicholas Brozovic, Laurie E. Drinkwater, Scott A. Drzyzga, Claire A. Jantz, José Fragoso, Daniel S. Holland, Timothy A. Kohler, Jianguo Liu, William J. Mcconnell, Herbert D.G. Maschner, James D.A. Millington, Michael Monticino, Guillermo Podestá, Robert Gilmore Pontius, Charles L. Redman, Nicholas J. Reo, David Sailor, Gerald Urquhart

Daugherty Water for Food Global Institute: Faculty Publications

Understanding the complexity of human–nature interactions is central to the quest for both human well-being and global sustainability. To build an understanding of these interactions, scientists, planners, resource managers, policymakers, and communities increasingly are collaborating across wide-ranging disciplines and knowledge domains. Scientists and others are generating new integrated knowledge on top of their requisite specialized knowledge to understand complex systems in order to solve pressing environmental and social problems (e.g., Carpenter et al. 2009). One approach to this sort of integration, bringing together detailed knowledge of various disciplines (e.g., social, economic, biological, and geophysical), has become known as the study …

The Water Footprint Assessment Manual: Setting The Global Standard, Arjen Y. Hoekstra, Ashok K. Chapagain, Maite M. Aldaya, Mesfin Mekonnen

Daugherty Water for Food Global Institute: Faculty Publications

This book contains the global standard for 'water footprint assessment' as developed and maintained by the Water Footprint Network (WFN). It covers a comprehensive set of definitions and methods for water footprint accounting. It shows how water footprints are calculated for individual processes and products, as well as for consumers, nations and businesses. It also includes methods for water footprint sustainability assessment and a library of water footprint response options. A shared standard on definitions and calculation methods is crucial given the rapidly growing interest in companies and governments to use water footprint accounts as a basis for formulating sustainable …

Eating Rate During A Fixed-Portion Meal Does Not Affect Postprandial Appetite And Gut Peptides Or Energy Intake During A Subsequent Meal, J. Phillip Karl, Andrew J. Young, Scott J. Montain

United States Army: Publications

Eating rate has recently been shown to influence energy intake and appetite during an ad libitummeal, and alter postprandial secretion of glucagon-like peptide-1 (GLP-1) and peptide-YY (PYY) following a fixed-portionmeal. Whether these effects influence satiety, as measured by energy intake at the subsequent meal, is unclear. We manipulated eating rate during a fixed-portion meal in order to examine how eating behavior and associated periprandial and postprandial responses of putative endocrine mediators of appetite would affect energy intake at the following meal in fifteen non-obese (BMI ≥ 25 kg/m²) and ten obese (BMI ≥ 30 kg/m²) healthy adult men and …

Effects Of Gage Length, Loading Rates, And Damage On The Strength Of Ppta Fibers, Jaeyoung Lim, James Q. Zheng, Karl Masters, Weinong W. Chen

United States Army: Publications

Axial tension and transverse compression experiments on single fibers were performed to investigate the mechanical behavior of three high-performance fibers (Kevlar ®, Kevlar ® 129, and Twaron ®) with diameters in the order of 9-12 μm. The single fibers were manufactured from 1998 through 2008. A miniaturized tensile Kolsky bar was used to determine the tensile response of PPTA single fibers at a high strain rate. Gage length and strain rate were found to have minimum effects on the tensile strength of PPTA single fibers. Manufacturing time over a decade was found to have negligible effects on the tensile strength …

Recombinant Paraoxonase 1 Protects Against Sarin And Soman Toxicity Following Microinstillation Inhalation Exposure In Guinea Pigs, Manojkumar Valiyaveettil, Yonas Alamneh, Peter Rezk, Michael W. Perkins, Alfred M. Sciuto, Bhupendra P. Doctor, Madhusoodana P. Nambiar

United States Army: Publications

To explore the efficacy of paraoxonase 1 (PON1) as a catalytic bioscavenger, we evaluated human recombinant PON1 (rePON1) expressed in Trichoplusia ni larvae against sarin and soman toxicity using microinstillation inhalation exposure in guinea pigs. Animals were pretreated intravenously with catalytically active rePON1, followed by exposure to 1.2 X LCt₅₀ sarin or soman. Administration of 5 units of rePON1 showed mild increase in the blood activity of the enzyme after 30 min, but protected the animals with a significant increase in survival rate along with minimal signs of nerve agent toxicity. Recombinant PON1 pretreated animals exposed to sarin or …

Comparison Of Dynamic Compression Behavior Of Single Crystal Sapphire To Polycrystalline Alumina, G. J. Kleiser, L.C. Chhabildas, W.D. Reinhart

United States Department of Energy: Publications

Due to the considerable interest in the shock loading behavior of aluminum oxide whether it is in the polycrystalline phase or in the single crystal phase well-controlled experiments were conducted to probe differences in shock loading behavior between these two materials. Previous studies concluded that the behavior was similar but careful examination of well-controlled experiments has revealed the two materials are different.Although the experimental results appear to have the same behavior in the shock velocity vs. particle velocity plane, they are considerably different in the stressevolume compression plane and evidence is provided that indicates the single crystal remains crystalline up …

Persistence Of Uranium Groundwater Plumes: Contrasting Mechanisms At Two Contaminated Doe Sites, John M. Zachara, James A. Davis, Philip E. Long, Kenneth H. Williams, Mark Freshley, James P. Mckinley

United States Department of Energy: Publications

We examine subsurface uranium (U) plumes at two U.S. Department of Energy sites located near large river systems. Following excavation of contaminated materials, both sites were projected to naturally flush remnant uranium contamination to levels below regulatory limits (e.g., 30 μg/L), within 10 years at the Hanford 300 Area (Columbia River) and 12 years at the Rifle site (Colorado River). The observed rate of attenuation was much lower than expected at both sites. Current understanding suggests that the two sites have common, but also differing mechanisms controlling plume persistence. At Hanford, the persistent source is adsorbed U(VI) in the deep …

Monarch: A High-Assurance Java-To-Java (J2j) Source-Code Migrator, Victor L. Winter, Jonathan Guerrero, Carl Reinke, James T. Perry

United States Department of Energy: Publications

JVM-based processors used in embedded systems are often scaled back versions of the standard JVM which do not support the full set of Java byte codes and native methods assumed by a JVM. As a result, code bases such as Java libraries must be migrated in order make them suitable for execution on the embedded JVM-based processor. This paper describes Monarch, a high-assurance Java-to-java (J2j) source code migrator that we are developing to assist such code migrations.

The Utility Of Shewanella Japonica For Microbial Fuel Cells, Justin C. Biffinger, Lisa A. Fitzgerald, Ricky Ray, Brenda J. Little, Stephen E. Lizewski, Emily R. Petersen, Bradley R. Ringeisen, Wesley C. Sanders, Paul E. Sheehan, Jeremy J. Pietron, Jeffrey W. Baldwin, Lloyd J. Nadeau, Glenn R. Johnson, Meghann Ribbens, Steven E. Finkel, Kenneth H. Nealson

United States Navy: Publications

Shewanella-containing microbial fuel cells (MFCs) typically use the fresh water wild-type strain Shewanella oneidensis MR-1 due to its metabolic diversity and facultative oxidant tolerance. However, S. oneidensis MR-1 is not capable of metabolizing polysaccharides for extracellular electron transfer. The applicability of Shewanella japonica (an agar-lytic Shewanella strain) for power applications was analyzed using a diverse array of carbon sources for current generation from MFCs, cellular physiological responses at an electrode surface, biofilm formation, and the presence of soluble extracellular mediators for electron transfer to carbon electrodes. Critically, air-exposed S. japonica utilizes biosynthesized extracellular mediators for electron transfer to carbon …

Investigation Of Electrical Transport In Hydrogenated Multiwalled Carbon Nanotubes, Adam L. Friedman, Hyunkyung Chun, Don Heiman, Yung Joon Jung, Latika Menon

United States Navy: Publications

Highly disordered multiwalled carbon nanotubes of large outer diameter (~60 nm) fabricated by means of chemical vapor deposition process inside porous alumina templates exhibit ferromagnetism when annealed in a H₂/Ar atmosphere. In the presence of an applied magnetic field, there is a transition from positive to negative magnetoresistance. The transition may be explained in terms of the Bright model for ordered and disordered carbon structures. Additionally, temperature dependent electrical transport experiments exhibit a zero-bias anomaly at low temperature.

Derivation Radical Subspace Arrangements, Will Taves, Max Wakefield

United States Navy: Publications

In this note we study modules of derivations on collections of linear subspaces in a finite dimensional vector space. The central aim is to generalize the notion of freeness from hyperplane arrangements to subspace arrangements. We call this generalization ‘derivation radical’. We classify all coordinate subspace arrangements that are derivation radical and show that certain subspace arrangements of the Braid arrangement are derivation radical. We conclude by proving that under an algebraic condition the subspace arrangement consisting of all codimension c intersections, where c is fixed, of a free hyperplane arrangement are derivation radical.

Sex Steroid And Thyroid Hormone Receptor Expressions In The Thyroid Of The American Alligator (Alligator Mississippiensis) During Different Life Stages, Dieldrich S. Bermudez, Jeremy P. Skotko, Yasuhiko Ohta, Ashley S.P. Boggs, Taisen Iguchi, Louis J. Guillette Jr.

United States Environmental Protection Agency: Publications

The expression of estrogen receptors, ESR1 (ERα) and ESR2 (ERβ), and androgen receptors (AR) in the thyroid gland has been reported in few vertebrate species other than a few mammals. This study reports the presence of sex steroid hormone receptors and thyroid receptors (ERα, ERβ, AR, TRα, and TRβ) in the thyroid gland of the American alligator at several life stages. It provides a semiquantification and distribution of ERα in the thyroid follicle cells using an immunohistochemical approach as well as reports quantitative differences in mRNA expression of ERα, ERβ, TRα, TRβ, and AR in the same tissue using quantitative …

Time-Lapse Three-Dimensional Inversion Of Complex Conductivity Data Using An Active Time Constrained (Atc) Approach, M. Karaoulis, A. Revil, D. D. Werkema, B. J. Minsley, W. F. Woodruff, A. Kemna

United States Environmental Protection Agency: Publications

Induced polarization (more precisely the magnitude and phase of impedance of the subsurface) is measured using a network of electrodes located at the ground surface or in boreholes. This method yields important information related to the distribution of permeability and contaminants in the shallow subsurface. We propose a new time-lapse 3-D modelling and inversion algorithm to image the evolution of complex conductivity over time.We discretize the subsurface using hexahedron cells. Each cell is assigned a complex resistivity or conductivity value. Using the finite-element approach, we model the in-phase and out-of-phase (quadrature) electrical potentials on the 3-D grid, which are then …

Bedside Method To Estimate Actual Body Weight In The Emergency Department, Robert G. Buckley, Christine R. Stehman, Frank L. Dos Santos, Robert H. Riggenburgh, Aaron Swenson, Nathan Mjos, Matt Brewer, Sheila Mulligan

United States Navy: Publications

Background:

Actual body weight (ABW) is important for accurate drug dosing in emergency settings. Oftentimes, patients are unable to stand to be weighed accurately or clearly state their most recent weight.

Objective:

Develop a bedside method to estimate ABW using simple anthropometric measurements.

Methods:

Prospective, blinded, cross-sectional convenience sampling of adult Emergency Department (ED) patients. A multiple linear regression equation from Derivation Phase (n = 208: 121 males, 87 females) found abdominal and thigh circumferences (AC and TC) had the best fit and an inter-rater correlation of 0.99 and 0.96, respectively: Male ABW (kg) = -47.8 + 0.78 * (AC) …

Relationship Of Surface Changes To Metal Leaching From Tungsten Composite Shot Exposed To Three Different Soil Types, Deborah Felt, Steven Larson, Chris Griggs, Catherine Nestler, Michelle Wynter

United States Army: Publications

Physical changes that occur on the surface of fired shots due to firing and impact with soil may increase the dissolution of muniton metals. Increased metal dissolution could potentially increase metal transport and leaching, affecting metal concentrations in surface and groundwater. This research describes the relationship between the surface changes on fired tungsten–nickel–iron (94% W:2% Ni:4% Fe) composite shots and metals leaching from those shots. Tungsten composite shot was fired into, and aged in, three soil types (Silty Sand, Sandy Clay, and Silt) in mesoscale rainfall lysimeters to simulate live-fire conditions and subsequent interactions between the metals of the composite …

Safety And Protective Efficacy Of Ina-Inactivated Venezuelan Equine Encephalitis Virus: Implication In Vaccine Development, Anuj Sharma, Paridhi Gupta, Pamela J. Glass, Michael D. Parker, Radha K. Maheshwari

United States Army: Publications

We have previously shown that a hydrophobic alkylating compound, 1,5-iodonaphthyl-azide (INA) can efficiently inactivate the virulent strain of Venezuelan equine encephalitis virus (VEEV), V3000 in vitro. In this study, we have evaluated the safety of INA-inactivated V3000 and V3526 and the protective efficacy of INA-inactivated V3000. INA-inactivated V3000 and V3526 did not cause disease in suckling mice. RNA isolated from the INA-inactivated V3000 and V3526 was also not infectious. Immunization of adult mice with INA-inactivated V3000 induced an anti-VEEV antibody response and protected mice from virulent VEEV challenge. The protective efficacy of INA-inactivated V3000 increased with the use of adjuvants. …

Dislocation–Twin Interactions In Nanocrystalline Fcc Metals, Y. T. Zhu, X. L. Wu, X. Z. Liao, J. Narayan, L. J. Keckés, S. N. Mathaudhu

United States Army: Publications

Dislocation interaction with and accumulation at twin boundaries have been reported to significantly improve the strength and ductility of nanostructured face-centered cubic (fcc) metals and alloys. Here we systematically describe plausible dislocation interactions at twin boundaries. Depending on the characteristics of the dislocations and the driving stress, possible dislocation reactions at twin boundaries include cross-slip into the twinning plane to cause twin growth or de-twinning, formation of a sessile stair-rod dislocation at the twin boundary, and transmission across the twin boundary. The energy barriers for these dislocation reactions are described and compared.

Test 2012a: New Holland Workmaster 55, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

An Alternative Approach To Integrating Plasticity Relations, Richard Becker

United States Army: Publications

A new plasticity integration algorithm is proposed based upon observations from the closed form integration of a generalized quadratic yield function over a single time step. The key to the approach is specification of the normal to the plastic flow potential as a function of the current state and strain increment. This uniquely defines the direction of the stress tensor for a convex, non-faceted flow potential. The stress magnitude and plastic strain increment are computed to satisfy the yield function. A non-quadratic, isotropic, associative flow model is coded to demonstrate accuracy and time step convergence following a step change in …

Nanoindentation Characterization Of Deformation And Failure Of Aluminum Oxynitride, J. J. Guo, K. Wang, T. Fujita, J. W. Mccauley, J. P. Singh, M. W. Chen

United States Army: Publications

A systematic study of the mechanical deformation and failure of transparent ceramic aluminum oxynitride (AlON) has been conducted using a depth-sensitive nanoindentation technique combined with transmission electron microscopy (TEM) and Raman spectroscopy. Although discrete displacement bursts appear in the load–depth profiles at high applied forces, a detectable high-pressure phase transition has not been found by means of micro-Raman spectroscopy and TEM. Instead, a high density of dissociated (1 1 0) dislocations can be observed underneath the nanoindenters, suggesting that extensive plastic deformation takes place in the brittle ceramic at high contact pressures. Moreover, nanoindentation-induced micro-cracks oriented along well-defined crystallographic planes …

Cottonwood Management Plan/Programmatic Environmental Assessment Proposed Implementation Of A Cottonwood Management Plan Along Six Priority Segments Of The Missouri River

United States Army Corps of Engineers, Omaha District

The U.S. Army Corps of Engineers (Corps) proposes to preserve existing stands and reestablish new stands of plains cottonwood (Populus deltoides) at selected public/government lands along the Missouri River in accordance with the Cottonwood Management Plan (CMP). The Proposed Action is the implementation of the CMP. The goal of the plan is to be a living document that preserves, creates, or restores cottonwood habitats along the Missouri River and meets the requirements of the USFWS 2003 Amended Biological Opinion (BiOp) concerning the bald eagle (Haliaeetus leucocephalus). The principal immediate focus of the CMP includes measures in …

Missouri River Recovery Program: 2009 Spring Pulse And Rises Drainage Monitoring And Evaluation

United States Army Corps of Engineers, Omaha District

Spring pulse releases for the benefit of the endangered pallid sturgeon were planned for March and May 2009 to mimic historic natural spring rises that occurred on the Missouri River before the closure of the main stem dams. The March spring pulse from Gavins Point Dam was not released in 2009 due to high downstream flows and the possibility of flow-limit violations. A 6.1 -kcfs May spring pulse was released in 2009.

The May spring pulse was monitored at 44 sites along the Missouri River. Nineteen of these were interior-drainage sites that were monitored for possible socioeconomic impacts to landowners. …