Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

2011

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 4351 - 4380 of 5801

Full-Text Articles in Engineering

Missouri Work Zone Capacity: Results Of Field Data Analysis, Ghulam Bham Ph.D., S. Hadi Khazraee Jan 2011

Missouri Work Zone Capacity: Results Of Field Data Analysis, Ghulam Bham Ph.D., S. Hadi Khazraee

Mid-America Transportation Center: Final Reports and Technical Briefs

This report presents the results of work zone field data analyzed on interstate highways in Missouri to determine the mean breakdown and queue-discharge flow rates as measures of capacity. Several days of traffic data collected at a work zone near Pacific, Missouri with a speed limit of 50 mph were analyzed in both the eastbound and westbound directions. As a result, a total of eleven breakdown events were identified using average speed profiles. The traffic flows prior to and after the onset of congestion were studied. Breakdown flow rates ranged between 1194 to 1404 vphpl, with an average of 1295 …


Roadside Grading Guidance - Phase I, Kevin D. Schrum, Francisco D. B. Albuquerque, Dean L. Sicking, Ronald K. Faller, John D. Reid Jan 2011

Roadside Grading Guidance - Phase I, Kevin D. Schrum, Francisco D. B. Albuquerque, Dean L. Sicking, Ronald K. Faller, John D. Reid

Mid-America Transportation Center: Final Reports and Technical Briefs

Provisions for the design of roadside foreslopes are not readily available. As a result, engineering judgment is often employed. Unfortunately, this can lead to inconsistent designs, where, inevitably, some designs will be too costly and other designs will be too dangerous. Therefore guidance has been compiled to lend consistency to the design of these foreslopes while maintaining the most economical and safe design.

This guidance was prepared after conducting a benefit-cost analysis using the Roadside Safety Analysis Program (RSAP). A large test matrix was developed in an attempt to simulate the most possible scenarios, leaving interpolation to a minimum. However, …


Retrieval Of Canopy Height Using Moderate-Resolution Imaging Spectroradiometer (Modis) Data, Zhuosen Wang, Crystal B. Schaaf, Philip Lewis, Yuri Knyazikhin, Mitchell A. Schull, Alan H. Strahler, Tian Yao, Ranga B. Myneni, Mark J. Chopping, Bryan J. Blair Jan 2011

Retrieval Of Canopy Height Using Moderate-Resolution Imaging Spectroradiometer (Modis) Data, Zhuosen Wang, Crystal B. Schaaf, Philip Lewis, Yuri Knyazikhin, Mitchell A. Schull, Alan H. Strahler, Tian Yao, Ranga B. Myneni, Mark J. Chopping, Bryan J. Blair

United States National Aeronautics and Space Administration: Publications

In this study we use the 500 m Moderate Resolution Imaging Spectroradiometer (MODIS) Bidirectional Reflectance Distribution Function (BRDF) product to develop multivariate linear regression models that estimate canopy heights over study sites at Howland Forest, Maine, Harvard Forest, Massachusetts and La Selva Forest, Costa Rica using (1) directional escape probabilities that are spectrally independent and (2) the directional spectral reflectances used to derive the directional escape probabilities. These measures of canopy architecture are compared with canopy height information retrieved from the airborne Laser Vegetation Imaging Sensor (LVIS). Both the escape probability and the directional reflectance approaches achieve good results, with …


Focused Ion Beam Patterned Fe Thin Films: A Study By Selective Area Stokes Polarimetry And Soft X-Ray Microscopy, P. J. Cook, T. H. Shen, P. J. Grundy, M.-Y. Im, P. Fischer, S. A. Morton, A. L. D. Kilcoyne Jan 2011

Focused Ion Beam Patterned Fe Thin Films: A Study By Selective Area Stokes Polarimetry And Soft X-Ray Microscopy, P. J. Cook, T. H. Shen, P. J. Grundy, M.-Y. Im, P. Fischer, S. A. Morton, A. L. D. Kilcoyne

United States Department of Energy: Publications

A combination of analytical techniques, with special emphasis on selective area Stokes polarimetry, has been used to explore the structural properties and magnetic behavior of focused ion beam patterned Fe thin films under controlled Ga+ ion irradiation. Ion irradiation at doses ranging from 7.7×1015 to 5.2×1016 Ga ions cm-2 did not noticeably alter the chemical properties of the Fe, but changes to the film structure and increased coercivity were observed even after the lowest doses. Magnetic transmission x-ray microscopy provided detailed information about the magnetization reversal process occurring within a patterned area of film comprising both …


Proceedings From The National Pipeline Safety Forum Jan 2011

Proceedings From The National Pipeline Safety Forum

United States Department of Transportation: Publications

The Forum was organized around three panel discussions intended to prompt discussion related to and culminating in the actions that PHMSA, states, and industry can take to increase pipeline safety. First, discussions were focused on both the known and perceived risks posed by pipelines, including the means by which these risks and threats are identified, measured, and evaluated. The second objective was to discuss the nature, scope, and extent of the challenges facing the industry and regulators as they decide how best to address and eliminate or mitigate these risks, and prevent future incidents. Financially-driven challenges were addressed along with …


Peer Review Report 2011 Jan 2011

Peer Review Report 2011

United States Department of Transportation: Publications

The purpose of this document is to report findings from the research peer reviews held April 14, April 20, April 26 & April 27, 2011 for PHMSA’s Pipeline Safety Research and Development Program. The findings and recommendations in this report are derived from the scoring and comments collected from the peer review panelists.

Department of Transportation (DOT) Operating Agencies (OA) are required to develop and execute a systematic process for peer reviews and for all influential and highly influential information that the OA plans to disseminate in the foreseeable future.

Through the Information Quality Act, Congress directed the Office of …


Error Analysis Of Large-Eddy Simulation Of The Turbulent Non-Premixed Sydney Bluff-Body Flame, A. M. Kempf, B. J. Geurts, J. C, Oefelein Jan 2011

Error Analysis Of Large-Eddy Simulation Of The Turbulent Non-Premixed Sydney Bluff-Body Flame, A. M. Kempf, B. J. Geurts, J. C, Oefelein

United States Department of Energy: Publications

A computational error analysis is applied to the large-eddy simulation of the turbulent non-premixed Sydney bluff-body flame, where the error is defined with respect to experimental data. The errorlandscape approach is extended to heterogeneous compressible turbulence, which is coupled to combustion as described by a flamelet model. The Smagorinsky model formulation is used to model the unknown turbulent stresses. We introduce several measures to quantify the total simulation error and observe a striking ‘valley-structure’ in the error that arises as function of the spatial resolution and the Smagorinsky length parameter. The optimal refinement strategy that can be extracted from this …


Combining Power Plant Water Needs And Carbon Dioxide Storage Using Saline Formations: Implications For Carbon Dioxide And Water Management Policies, Peter Kobos, Malynda Cappelle, Jim Krumhansl, Thomas Dewers, Andrea Mcnemar, David Borns Jan 2011

Combining Power Plant Water Needs And Carbon Dioxide Storage Using Saline Formations: Implications For Carbon Dioxide And Water Management Policies, Peter Kobos, Malynda Cappelle, Jim Krumhansl, Thomas Dewers, Andrea Mcnemar, David Borns

United States Department of Energy: Publications

Research involving management of carbon dioxide has increased markedly over the last decade as it relates to concerns over climate change. Capturing and storing carbon dioxide (CO2) in geological formations is one of many proposed methods to manage, and likely reduce, CO2 emissions from burning fossil fuels in the electricity sector. Saline formations represent a vast storage resource, and the waters they contain could be managed for beneficial use. To address this issue, a methodology was developed to test the feasibility of linking coal-fired power plants, deep saline formations for CO2 storage, and extracting and treating …


Solubility Of Fe2(Oh)3cl (Pure-Iron End-Member Of Hibbingite) In Nacl And Na2so4 Brines, Martin Nemer, Yongliang Xiong, Ahmed Ismail, Je-Hun Jang Jan 2011

Solubility Of Fe2(Oh)3cl (Pure-Iron End-Member Of Hibbingite) In Nacl And Na2so4 Brines, Martin Nemer, Yongliang Xiong, Ahmed Ismail, Je-Hun Jang

United States Department of Energy: Publications

Pure-iron end-member hibbingite, Fe2(OH)3Cl(s), may be important to geological repositories in salt formations, as it may be a dominant corrosion product of steel waste canisters in an anoxic environment in Na–Cl- and Na–Mg–Cl-dominated brines. In this study, the solubility of Fe2(OH)3Cl(s), the pure-iron endmember of hibbingite (FeII, Mg)2(OH)3Cl(s), and Fe(OH)2(s) in 0.04 m to 6 m NaCl brines has been determined. For the reaction

Fe2 (OH)3Cl(s) + 3H+↔ 3H2O + 2Fe2+ + Cl−,

the …


Nonlocal Instability Analysis Of Fcc Bulk And (100) Surfaces Under Uniaxial Stretching, Geng Yun, Penghui Cao, Jonathan Zimmerman, Terry Delph, Harold Park Jan 2011

Nonlocal Instability Analysis Of Fcc Bulk And (100) Surfaces Under Uniaxial Stretching, Geng Yun, Penghui Cao, Jonathan Zimmerman, Terry Delph, Harold Park

United States Department of Energy: Publications

The objective of this paper is to examine the instability characteristics of both a bulk FCC crystal and a (100) surface of an FCC crystal under uniaxial stretching along a h100i direction using an atomisticbased nonlocal instability criterion. By comparison to benchmark atomistic simulations, we demonstrate that for both the FCC bulk and (100) surface, about 5000–10,000 atoms are required in order to obtain an accurate converged value for the instability strain and a converged instability mode. The instability modes are fundamentally different at the surface as compared to the bulk, but in both cases a strong dependence of the …


Evidence For Multiple Modes Of Uranium Immobilization By An Anaerobic Bacterium, Allison E. Ray, John R. Bargar, Vaideeswaran Sivaswamy, Alice C. Dohnalkova, Yoshiko Fujita, Brent M. Peyton, Timothy S. Magnuson Jan 2011

Evidence For Multiple Modes Of Uranium Immobilization By An Anaerobic Bacterium, Allison E. Ray, John R. Bargar, Vaideeswaran Sivaswamy, Alice C. Dohnalkova, Yoshiko Fujita, Brent M. Peyton, Timothy S. Magnuson

United States Department of Energy: Publications

Microbial reduction of hexavalent uranium has been studied widely for its potential role in bioremediation and immobilization of soluble U(VI) in contaminated groundwater. More recently, some microorganisms have been examined for their role in immobilization of U(VI) via precipitation of uranyl phosphate minerals mediated by microbial phosphate release, alleviating the requirement for long-term redox control. Here, we investigated the mechanism of U(VI) removal mediated by an environmental isolate, strain UFO1, that is indigenous to the Field Research Center (FRC) in Oak Ridge, TN and has been detected in U(VI)- contaminated sediments. Changes in U(VI) speciation were examined in the presence …


Quantifying Differences In The Impact Of Variable Chemistry On Equilibrium Uranium(Vi) Adsorption Properties Of Aquifer Sediments, Deborah Stoliker, Douglas Kent, John M. Zachara Jan 2011

Quantifying Differences In The Impact Of Variable Chemistry On Equilibrium Uranium(Vi) Adsorption Properties Of Aquifer Sediments, Deborah Stoliker, Douglas Kent, John M. Zachara

United States Department of Energy: Publications

Uranium adsorption − desorption on sediment samples collected from the Hanford 300-Area, Richland, WA varied extensively over a range of field-relevant chemical conditions, complicating assessment of possible differences in equilibrium adsorption properties. Adsorption equilibrium was achieved in 500−1000 h although dissolved uranium concentrations increased over thousands of hours owing to changes in aqueous chemical composition driven by sediment-water reactions. A nonelectrostatic surface complexation reaction, >SOH + UO22+ + 2CO32- = >SOUO2(CO3HCO3)2- , provided the best fit to experimental data for each sediment sample resulting in a range of conditional …


River-Induced Flow Dynamics In Long-Screen Wells And Impact On Aqueous Samples, Vince R. Vermeul, James Mckinley, Darrell R. Newcomer, Robert D. Mackley, John M. Zachara Jan 2011

River-Induced Flow Dynamics In Long-Screen Wells And Impact On Aqueous Samples, Vince R. Vermeul, James Mckinley, Darrell R. Newcomer, Robert D. Mackley, John M. Zachara

United States Department of Energy: Publications

Previously published field investigations and modeling studies have demonstrated the potential for sample bias associated with vertical wellbore flow in conventional monitoring wells constructed with long-screened intervals. This article builds on the existing body of literature by (1) demonstrating the utility of continuous (i.e., hourly measurements for ∼1 month) ambient wellbore flow monitoring and (2) presenting results from a field experiment where relatively large wellbore flows (up to 4 L/min) were induced by aquifer hydrodynamics associated with a fluctuating river boundary located approximately 250 m from the test well. The observed vertical wellbore flows were strongly correlated with fluctuations in …


Genome Sequence Of Victivallis Vadensis Atcc Baa-548, An Anaerobic Bacterium From The Phylum Lentisphaerae, Isolated From The Human Gastrointestinal Tract, Mark W. J. Van Passel, Ravi Kant, Airi Palva, Susan Lucas, Alex Copeland, Alla Lapidus, Tijana Glavina Del Rio, Eileen Dalin, Hope Tice, David Bruce, Lynne Goodwin, Sam Pitluck, Karen Walston Davenport, David Sims, Thomas Brettin, John Detter, Shunsheng Han, Frank Larimer, Miriam Land, Loren Hauser, Nikos C. Kyrpides, Galina Ovchinnikova, P. Paul Richardson, Willem M. De Vos, Hauke Smidt, Erwin G. Zoetendal Jan 2011

Genome Sequence Of Victivallis Vadensis Atcc Baa-548, An Anaerobic Bacterium From The Phylum Lentisphaerae, Isolated From The Human Gastrointestinal Tract, Mark W. J. Van Passel, Ravi Kant, Airi Palva, Susan Lucas, Alex Copeland, Alla Lapidus, Tijana Glavina Del Rio, Eileen Dalin, Hope Tice, David Bruce, Lynne Goodwin, Sam Pitluck, Karen Walston Davenport, David Sims, Thomas Brettin, John Detter, Shunsheng Han, Frank Larimer, Miriam Land, Loren Hauser, Nikos C. Kyrpides, Galina Ovchinnikova, P. Paul Richardson, Willem M. De Vos, Hauke Smidt, Erwin G. Zoetendal

United States Department of Energy: Publications

Victivallis vadensis ATCC BAA-548 represents the first cultured representative from the novel phylum Lentisphaerae, a deep-branching bacterial lineage. Few cultured bacteria from this phylum are known, and V. vadensis therefore represents an important organism for evolutionary studies. V. vadensis is a strictly anaerobic sugar-fermenting isolate from the human gastrointestinal tract.


Ambient- And High-Temperature Mechanical Properties Of Isochronally Aged Al–0.06sc, Al–0.06zr And Al–0.06sc–0.06zr (At.%) Alloys, Keith E. Knipling, David N. Seidman, David C. Dunand Jan 2011

Ambient- And High-Temperature Mechanical Properties Of Isochronally Aged Al–0.06sc, Al–0.06zr And Al–0.06sc–0.06zr (At.%) Alloys, Keith E. Knipling, David N. Seidman, David C. Dunand

United States Navy: Publications

Ambient- and high-temperature precipitation strengthening are investigated in Al–0.06Sc, Al–0.06Zr and Al–0.06Sc–0.06Zr (at.%) alloys. Following solidification, Sc is concentrated at the dendrite peripheries while Zr is segregated at the dendrite cores. During isochronal aging, precipitation of Al3Sc (L12) commences between 250 and 300 °C for Al–0.06Sc, and reaches a 429 MPa peak microhardness at 325 °C. For Al–0.06Zr, precipitation of Al3Zr (L12) first occurs between 400 and 425 °C and reaches a 295 MPa peak microhardness at 475 °C. A pronounced synergistic effect is observed when both Sc and Zr are present. Above 325 °C, Zr …


A Phase Field Model Of Deformation Twinning: Nonlinear Theory And Numerical Simulations, J. D. Clayton, J. Knap Jan 2011

A Phase Field Model Of Deformation Twinning: Nonlinear Theory And Numerical Simulations, J. D. Clayton, J. Knap

United States Army: Publications

A continuum phase field theory and corresponding numerical solution methods are developed to describe deformation twinning in crystalline solids. An order parameter is associated with the magnitude of twinning shear, i.e., the lattice transformation associated with twinning. The general theory addresses the following physics: large deformations, nonlinear anisotropic elastic behavior, and anisotropic phase boundary energy. The theory is applied towards prediction of equilibrium phenomena in the athermal and non-dissipative limit, whereby equilibrium configurations of an externally stressed crystal are obtained via incremental minimization of a free energy functional. Outcomes of such calculations are elastic fields (e.g., displacement, strain, stress, and …


Investigations Of Transcript Expression In Fathead Minnow (Pimephales Promelas) Brain Tissue Reveal Toxicological Impacts Of Rdx Exposure, Kurt A. Gust, Mitchell S. Wilbanks, Xin Guan, Mehdi Pirooznia, Tanwir Habib, Leslie Yoo, Henri Wintz, Chris D. Vulpe, Edward J. Perkins Jan 2011

Investigations Of Transcript Expression In Fathead Minnow (Pimephales Promelas) Brain Tissue Reveal Toxicological Impacts Of Rdx Exposure, Kurt A. Gust, Mitchell S. Wilbanks, Xin Guan, Mehdi Pirooznia, Tanwir Habib, Leslie Yoo, Henri Wintz, Chris D. Vulpe, Edward J. Perkins

United States Army: Publications

Production, usage and disposal of the munitions constituent (MC) cyclotrimethylenetrinitramine (RDX) has led to environmental releases on  military facilities. The chemical attributes of RDX are conducive for leaching to surface water which may put aquatic organisms at risk of exposure. Because RDX has been observed to cause aberrant neuromuscular effects across a wide range of animal phyla, we assessed the effects of RDX on central nervous system (CNS) functions in the representative aquatic ecotoxicological model species, fathead minnow (Pimephales promelas). We developed a fathead minnow brain-tissue cDNA library enriched for transcripts differentially expressed in response to RDX and …


Fatigue-Induced Grain Coarsening In Nanocrystalline Platinum Films, Roi A. Meirom, Daan Hein Alsem, Amber L. Romasco, Trevor Clark, Ronald G. Polcawich, Jeffrey S. Pulskamp, Madan Dubey, Robert O. Ritchie, Christopher L. Muhlstein Jan 2011

Fatigue-Induced Grain Coarsening In Nanocrystalline Platinum Films, Roi A. Meirom, Daan Hein Alsem, Amber L. Romasco, Trevor Clark, Ronald G. Polcawich, Jeffrey S. Pulskamp, Madan Dubey, Robert O. Ritchie, Christopher L. Muhlstein

United States Army: Publications

Mechanisms to explain the unique mechanical behavior of nanograined metals focus primarily on grain and grain boundary mobility. In most nanograined metal materials systems (both pure and alloyed) it has not been possible to decouple these time- and cycle-dependent contributions. In contrast, the 460 nm thick, (1 1 1) textured, nanograined platinum thin films evaluated in this work have robust grain morphologies that allow us to uniquely identify the fatigue damage accumulation processes. Unlike other reports of face-centered cubic metal behavior, the platinum films exhibited a particularly limited range of fatigue crack growth (<3 MPa √m) with extremely large (~10.5) power law exponents typically associated with fatigue of structural ceramics and ordered intermetallics. Transmission electron microscopy and fatigue crack growth data suggest that the crack growth mechanism appears to be intrinsic in origin and dislocation mediated.


Thermoreversible And Remendable Glass–Polymer Interface For Fiber-Reinforced Composites, Amy M. Peterson, Robert E. Jensen, Giuseppe R. Palmese Jan 2011

Thermoreversible And Remendable Glass–Polymer Interface For Fiber-Reinforced Composites, Amy M. Peterson, Robert E. Jensen, Giuseppe R. Palmese

United States Army: Publications

Adhesion of the reinforcement to the polymer matrix is essential for load transfer from the polymer matrix to the reinforcement material in fiber-reinforced composites. The reversible Diels–Alder reaction between a furan-functionalized epoxy-amine thermosetting matrix with a maleimide-functionalized glass fiber was used to impart remendability at the polymer–glass interface for potential application in glass fiber-reinforced composites. At room temperature the Diels–Alder adduct is formed spontaneously and above 90 °C the adduct breaks apart to reform the original furan and maleimide moieties. Healing of the interface was investigated with single fiber microdroplet pull-out testing. Following complete failure of this interface, significant healing …


Micro-Cracks Informed Damage Models For Brittle Solids, Xiaodan Ren, Jiun-Shyan Chen, Jie Li, T. R. Slawson, M. J. Roth Jan 2011

Micro-Cracks Informed Damage Models For Brittle Solids, Xiaodan Ren, Jiun-Shyan Chen, Jie Li, T. R. Slawson, M. J. Roth

United States Army: Publications

A class of micro-cracks informed damage models for describing the softening behavior of brittle solids is proposed, in which damage evolution is treated as a consequence of micro-crack propagation. The homogenized stress–strain relation in the cracked microscopic cell defines the degradation tensor, which can be obtained by the equivalence between the averaged strain energy of the microscopic cell and the strain energy density of the homogenized material. This energy equivalence relationship serves as an energy bridging vehicle between the damaged continuum and the cracked microstructure. Several damage evolution equations are obtained by this energy bridging method. The size effect of …


Antimicrobial Decapeptide Ksl-W Attenuates Candida Albicans Virulence By Modulating Its Effects On Toll-Like Receptor, Human Β-Defensin, And Cytokine Expression By Engineered Human Oral Mucosa, A. Semlali, K. P. Leung, S. Curt, M. Rouabhia Jan 2011

Antimicrobial Decapeptide Ksl-W Attenuates Candida Albicans Virulence By Modulating Its Effects On Toll-Like Receptor, Human Β-Defensin, And Cytokine Expression By Engineered Human Oral Mucosa, A. Semlali, K. P. Leung, S. Curt, M. Rouabhia

United States Army: Publications

We investigated the toxicity of synthetic antimicrobial decapeptide KSL-W on normal human gingival epithelial cell cultures, its effect on Candida albicans adhesion and growth, and the activation of epithelial cell innate immunity. Our results indicate that KSL-W had no toxic effect on cell adhesion or growth, suggesting its safe use with human cells. Pre-treating C. albicans with KSL-W attenuated the yeast’s virulence as demonstrated by its reduced adhesion and growth on engineered human oral mucosa epithelium and the subsequent decreased expression of some innate defense molecules by targeted epithelial cells. Indeed, the expression of Toll-like receptors and human β-defensins was …


Protective Efficacy Of Catalytic Bioscavenger, Paraoxonase 1 Against Sarin And Soman Exposure In Guinea Pigs, Manojkumar Valiyaveettil, Yonas Alamneh, Peter Rezk, Lionel Biggemann, Michael W. Perkins, Alfred M. Sciuto, Bhupendra P. Doctor, Madhusoodana P. Nambiar Jan 2011

Protective Efficacy Of Catalytic Bioscavenger, Paraoxonase 1 Against Sarin And Soman Exposure In Guinea Pigs, Manojkumar Valiyaveettil, Yonas Alamneh, Peter Rezk, Lionel Biggemann, Michael W. Perkins, Alfred M. Sciuto, Bhupendra P. Doctor, Madhusoodana P. Nambiar

United States Army: Publications

Human paraoxonase 1 (PON1) has been portrayed as a catalytic bioscavenger which can hydrolyze large amounts of chemical warfare nerve agents (CWNAs) and organophosphate (OP) pesticides compared to the stoichiometric bioscavengers such as butyrylcholinesterase. We evaluated the protective efficacy of purified human and rabbit serum PON1 against nerve agents sarin and soman in guinea pigs. Catalytically active PON1 purified from human and rabbit serum was intravenously injected to guinea pigs, which were 30 min later exposed to 1.2 × LCt50 sarin or soman using a microinstillation inhalation exposure technology. Pre-treatment with 5 units of purified human and rabbit serum …


The Aerodynamic Behaviour Of Respiratory Aerosols, Kristin K. Grosskopf Jan 2011

The Aerodynamic Behaviour Of Respiratory Aerosols, Kristin K. Grosskopf

Department of Construction Engineering and Management: Faculty Publications

Hospital acquired infections (HAIs) claim on average 90,000 lives each year in the U.S., nearly three times the number of annual highway deaths. Although fewer than 15% of HAIs are directly attributable to airborne transmission, more than a third may be caused by surface microbes aerosolized by the movement of air from building systems, people and equipment. As a result, a study was devised to use a synthetic respiratory aerosol to track the movement airborne contagion with respect to various environmental conditions in a healthcare environment.


Complex Engineering System Learning Through Study Of Engineering Failure Cases Using 3d Animations, Zhigang Shen, Yimin Zhu Jan 2011

Complex Engineering System Learning Through Study Of Engineering Failure Cases Using 3d Animations, Zhigang Shen, Yimin Zhu

Department of Construction Engineering and Management: Faculty Publications

Complex engineering systems often require dynamic coordination of multidisciplinary teams with conflicting objectives. Failing to understand the complex relationships among the conflicting objectives may result in serious engineering failures. In engineering education, one of the challenges in teaching complex systems is the lack of effective tools to demonstrate system dynamics, especially spatial-temporal relationships in the system. The described project in this paper is supported by grants from Engineering Education program of the National Science Foundation. In the project civil/construction engineering cases are used as the context to test the proposed new teaching/learning tool on the subject and to demonstrate the …


Interpreting Tree Responses To Thinning And Fertilization Using Tree-Ring Stable Isotopes, J. Renée Brooks, Alan K. Mitchell Jan 2011

Interpreting Tree Responses To Thinning And Fertilization Using Tree-Ring Stable Isotopes, J. Renée Brooks, Alan K. Mitchell

United States Environmental Protection Agency: Publications

Carbon sequestration has focused renewed interest in understanding how forest management affects forest carbon gain over timescales of decades, and yet details of the physiological mechanisms over decades are often lacking for understanding long-term growth responses to management.

Here, we examined tree-ring growth patterns and stable isotopes of cellulose (δ13Ccell and δ18Ocell) in a thinning and fertilization controlled experiment where growth increased substantially in response to treatments to elucidate physiological data and to test the dual isotope approach for uses in other locations.

δ13Ccell and δ18Ocell results …


Detection Of Illicit Drugs On Surfaces Using Direct Analysis In Real Time (Dart) Time‐Of‐Flight Mass Spectrometry, Andrew H. Grange, G. Wayne Sovocool Jan 2011

Detection Of Illicit Drugs On Surfaces Using Direct Analysis In Real Time (Dart) Time‐Of‐Flight Mass Spectrometry, Andrew H. Grange, G. Wayne Sovocool

United States Environmental Protection Agency: Publications

Methamphetamine (meth) from meth syntheses or habitual meth smoking deposited on household surfaces poses human health hazards. The U.S. State Departments of Health require decontamination of sites where meth was synthesized (meth labs) before they are sold. National Institute for Occupational Safety and Health (NIOSH) methods for meth analysis require wipe sampling, extraction, clean‐up, solvent exchange, derivatization, and/or mass spectral analysis using selected ion monitoring. Rapid and inexpensive analyses could screen for drug‐contamination within structures with greater spatial resolution, provide real‐time analyses during decontamination, and provide thorough documentation of successful clean ups. Herein an autosampler/open‐air ion source time‐of‐flight mass spectrometric …


Remediation Of Napl Source Zones: Lessons Learned From Field Studies At Hill And Dover Afb, John E. Mccray, Geoffrey R. Tick, James W. Jawitz, John S. Gierke, Mark L. Brusseau, Ronald W. Falta, Robert C. Knox, David A. Sabatini, Michael D. Annable, Jeffrey H. Harwell, A. Lynn Wood Jan 2011

Remediation Of Napl Source Zones: Lessons Learned From Field Studies At Hill And Dover Afb, John E. Mccray, Geoffrey R. Tick, James W. Jawitz, John S. Gierke, Mark L. Brusseau, Ronald W. Falta, Robert C. Knox, David A. Sabatini, Michael D. Annable, Jeffrey H. Harwell, A. Lynn Wood

United States Environmental Protection Agency: Publications

Innovative remediation studies were conducted between 1994 and 2004 at sites contaminated by nonaqueous phase liquids (NAPLs) at Hill and Dover AFB, and included technologies that mobilize, solubilize, and volatilize NAPL: air sparging (AS), surfactant flushing, cosolvent flooding, and flushing with a complexingsugar solution. The experiments proved that aggressive remedial efforts tailored to the contaminant can remove more than 90% of the NAPL-phase contaminant mass. Site-characterization methods were tested as part of these field efforts, including partitioning tracer tests, biotracer tests, and mass-flux measurements. A significant reduction in the groundwater contaminant mass flux was achieved despite incomplete removal of the …


Diagnosis Of Multiple Scan-Chain Faults In The Presence Of System Logic Defects, Zhen Chen, Sharad C. Seth, Dong Xiang, Bhargab B. Bhattacharya Jan 2011

Diagnosis Of Multiple Scan-Chain Faults In The Presence Of System Logic Defects, Zhen Chen, Sharad C. Seth, Dong Xiang, Bhargab B. Bhattacharya

School of Computing: Conference and Workshop Papers

We present a combined hardware-software based approach to scan-chain diagnosis, when the outcome of a test may be affected by system faults occurring in the logic outside of the scan chain. For the hardware component we adopt the double-tree scan (DTS) chain architecture, which has previously been shown to be effective in reducing power, volume, and application time of tests for stuck-at and delay faults. We develop a version of flush test which can resolve a multiple fault in a DTS chain to a small number of suspect candidates. Further resolution to a unique multiple fault is enabled by the …


2-Edge-Connectivity And 2-Vertex-Connectivity With Fault Containment, Abusayeed Saifullah Jan 2011

2-Edge-Connectivity And 2-Vertex-Connectivity With Fault Containment, Abusayeed Saifullah

All Computer Science and Engineering Research

Self-stabilization for non-masking fault-tolerant distributed system has received considerable research interest over the last decade. In this paper, we propose a self-stabilizing algorithm for 2-edge-connectivity and 2-vertex-connectivity of an asynchronous distributed computer network. It is based on a self-stabilizing depth-first search, and is not a composite algorithm in the sense that it is not composed of a number of self-stabilizing algorithms that run concurrently. The time and space complexities of the algorithm are the same as those of the underlying self-stabilizing depth-first search algorithm.


Implementation And Evaluation Of Mixed-Criticality Scheduling Approaches For Periodic Tasks, Huang-Ming Huang, Christopher Gill, Chenyang Lu Jan 2011

Implementation And Evaluation Of Mixed-Criticality Scheduling Approaches For Periodic Tasks, Huang-Ming Huang, Christopher Gill, Chenyang Lu

All Computer Science and Engineering Research

Traditional fixed-priority scheduling analysis for periodic task sets is based on the assumption that all tasks are equally critical to the correct operation of the system. Therefore, every task has to be schedulable under the scheduling policy, and estimates of tasks’ worst case execution times must be conservative in case a task runs longer than is usual. To address the significant under-utilization of a system’s resources under normal operating conditions that can arise from these assumptions, three main approaches have been proposed: priority assignment, period transformation, and zero-slack scheduling. However, to date there has been no quantitative comparison of system …