Engineering Commons^™

Photoionization Measurements For The Iron Isonuclear Sequence Fe3+, Fe5+, And Fe7+, M. F. Gharaibeh, A. Aguilar, A. M. Covington, E. D. Emmons, S. W. J. Scully, R. A. Phaneuf, A. Muller, J. D. Bozek, A. L. D. Kilcoyne, A. S. Schlachter, I. Alvarez, C. Cisneros, G. Hinojosa

United States Department of Energy: Publications

Cross sections for single photoionization of Fe³⁺, Fe⁵⁺, and Fe⁷⁺ ions were measured at spectral resolutions of 0.04, 0.15, and 0.13 eV, respectively, by merging mass- and charge-selected ion beams with a beam of monochromatized synchrotron undulator radiation. The measurements span photon energy ranges beginning at the ionization thresholds and extending several tens of electron volts to include the most important resonant contributions due to 3p–nd transitions to autoionizing states. The photoion yield spectra are characterized by narrow resonances and also broad features in Fe³⁺ and Fe⁵⁺ that are believed to result …

An Approach To Crystallizing Proteins By Metal-Mediated Synthetic Symmetrization, Arthur Laganowsky, Minglei Zhao, Angela B. Soriaga, Michael R. Sawaya, Duilio Cascio, Todd O. Yeates

United States Department of Energy: Publications

Combining the concepts of synthetic symmetrization with the approach of engineering metal-binding sites, we have developed a new crystallization methodology termed metal-mediated synthetic symmetrization. In this method, pairs of histidine or cysteine mutations are introduced on the surface of target proteins, generating crystal lattice contacts or oligomeric assemblies upon coordination with metal. Metal-mediated synthetic symmetrization greatly expands the packing and oligomeric assembly possibilities of target proteins, thereby increasing the chances of growing diffraction-quality crystals. To demonstrate this method, we designed various T4 lysozyme (T4L) and maltose-binding protein (MBP) mutants and cocrystallized them with one of three metal ions: copper (Cu …

Modification Of Native Grasses For Biofuel Production May Increase Virus Susceptibility, Abbie C. Schrotenboer, Michael S. Allen, Carolyn M. Malmstrom

United States Department of Energy: Publications

Bioenergy production is driving modifications to native plant species for use as novel biofuel crops. Key aims are to increase crop growth rates and to enhance conversion efficiency by reducing biomass recalcitrance to digestion. However, selection for these biofuel-valuable traits has potential to compromise plant defenses and alter interactions with pests and pathogens. Insect-vectored plant viruses are of particular concern because perennial crops have potential to serve as virus reservoirs that influence regional disease dynamics. In this study, we examined relationships between growth rates and biomass recalcitrance in five switchgrass (Panicum virgatum) populations, ranging from near wild type …

Ecosystem Services Altered By Human Changes In The Nitrogen Cycle: A New Perspective For Us Decision Making, Jana E. Compton, John A. Harrison, Robin L. Dennis, Tara L. Greaver, Brian H. Hill, Stephen J. Jordan, Henry Walker, Holly V. Campbell

United States Environmental Protection Agency: Publications

Human alteration of the nitrogen (N) cycle has produced benefits for health and well-being, but excess N has altered many ecosystems and degraded air and water quality. US regulations mandate protection of the environment in terms that directly connect to ecosystem services. Here, we review the science quantifying effects of N on key ecosystem services, and compare the costs of N-related impacts or mitigation using the metric of cost per unit of N. Damage costs to the provision of clean air, reflected by impaired human respiratory health, are well characterized and fairly high (e.g. costs of ozone and particulate damages …

Toxicity And Recovery In The Pregnant Mouse After Gestational Exposure To The Cyanobacterial Toxin, Cylindrospermopsin, N. Chernoff, E. H. Rogers, R. D. Zehr, M. I. Gage, D. E. Malarkey, C. A. Bradfield, Y. Liu, J. E. Schmid, R. H. Jaskot, J. H. Richards, C. R. Wood, M. B. Rosen

United States Environmental Protection Agency: Publications

Cylindrospermopsin (CYN) is a tricyclic alkaloid toxin produced by fresh water cyanobacterial species worldwide. CYN has been responsible for both livestock and human poisoning after oral exposure. This study investigated the toxicity of CYN to pregnant mice exposed during different segments of gestation. The course of recovery and individual responses to the toxin were evaluated. Adverse effects of CYN were monitored up to 7 weeks post-dosing by clinical examination, histopathology, biochemistry and gene expression. Exposure on gestational days (GD) 8–12 induced significantly more lethality than GD13–17 exposure. Periorbital, gastrointestinal and distal tail hemorrhages were seen in both groups. Serum markers …

Maternal Influences On Epigenetic Programming Of The Developing Hypothalamic-Pituitary-Adrenal Axis, Curtis E. Grace, Sung-Je Kim, John M. Rogers

United States Environmental Protection Agency: Publications

Parental and environmental factors during the prenatal and postnatal periods permanently affect the physiology and metabolism of offspring, potentially increasing disease risk later in life. Underlying mechanisms are being elucidated, and effects on a number of organs and metabolic pathways are likely involved. In this review, we consider effects on the developing hypothalamic-pituitary-adrenal (HPA) axis, which may represent a common pathway for developmental programming. The focus is on prenatal and early postnatal development, during which the HPA axis may be programmed in a manner that affects health for a lifetime. Programming of the HPA axis involves, at least in part, …

Current And Future Needs For Developmental Toxicity Testing, Susan L. Makris, James H. Kim, Amy Ellis, Willem Faber, Wafa Harrouk, Joseph M. Lewis, Merle G. Paule, Jennifer Seed, Melissa Tassinari, Rochelle Tyl

United States Environmental Protection Agency: Publications

A review is presented of the use of developmental toxicity testing in the United States and international regulatory assessment of human health risks associated with exposures to pharmaceuticals (human and veterinary), chemicals (agricultural, industrial, and environmental), food additives, cosmetics, and consumer products. Developmental toxicology data are used for prioritization and screening of pharmaceuticals and chemicals, for evaluating and labeling of pharmaceuticals, and for characterizing hazards and risk of exposures to industrial and environmental chemicals. The in vivo study designs utilized in hazard characterization and dose-response assessment for developmental outcomes have not changed substantially over the past 30 years and have …

Aryl Hydrocarbon Receptor Activation During Pregnancy, And In Adult Nulliparous Mice, Delays The Subsequent Development Of Dmba-Induced Mammary Tumors, Tao Wang, Heather M. Gavin, Volker M. Arlt, B. Paige Lawrence, Suzanne E. Fenton, Daniel Medina, Beth A. Vorderstrasse

United States Environmental Protection Agency: Publications

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), the prototypic ligand for the aryl hydrocarbon receptor (AhR), promotes tumor formation in some model systems. However, with regard to breast cancer, epidemiological and animal studies are inconclusive as to whether exposure increases tumor incidence or may instead be protective. We have previously reported that mice exposed to TCDD during pregnancy have impaired differentiation of mammary tissue, including decreased branching and poor development of lobuloalveolar structures. Because normal pregnancy-induced mammary differentiation may protect against subsequent neoplastic transformation, we hypothesized that TCDD-treated mice would be more susceptible to chemical carcinogenesis after parturition. To test this, mice were …

Emergy As A Life Cycle Impact Assessment Indicator A Gold Mining Case Study, Wesley W. Ingwesen

United States Environmental Protection Agency: Publications

Founded in thermodynamics and systems ecology, emergy evaluation is a method to associate a product with its dependencies on all upstream environmental and resource flows using a common unit of energy. Emergy is thus proposed as an indicator of aggregate resource use for life cycle assessment (LCA). An LCA of gold mining, based on an original life cycle inventory of a large gold mine in Peru, is used to demonstrate how emergy can be incorporated as an impact indicator into a process-based LCA model. The results demonstrate the usefulness of emergy in the LCA context. The adaptation of emergy evaluation, …

Evolution Of Natural History Information In The 21st Century – Developing An Integrated Framework For Biological And Geographical Data, Deborah A. Reusser, Henry Lee Ii

United States Environmental Protection Agency: Publications

Threats to marine and estuarine species operate over many spatial scales, from nutrient enrichment at the watershed/estuarine scale to invasive species and climate change at regional and global scales. To help address research questions across these scales, we provide here a standardized framework for a biogeographical information system containing queriable biological data that allows extraction of information on multiple species, across a variety of spatial scales based on species distributions, natural history attributes and habitat requirements. As scientists shift from research on localized impacts on individual species to regional and global scale threats, macroecological approaches of studying multiple species over …

Effects Of Biologically-Active Chemical Mixtures On Fish In A Wastewater-Impacted Urban Stream, Larry B. Barber, Gregory K. Brown, Todd G. Nettesheim, Elizabeth W. Murphy, Stephen E. Bartell, Heiko L. Schoenfuss

United States Environmental Protection Agency: Publications

Stream flow in urban aquatic ecosystems often is maintained by water-reclamation plant (WRP) effluents that contain mixtures of natural and anthropogenic chemicals that persist through the treatment processes. In effluent-impacted streams, aquatic organisms such as fish are continuously exposed to biologically-active chemicals throughout their life cycles. The North Shore Channel of the Chicago River (Chicago, Illinois) is part of an urban ecosystem in which >80% of the annual flow consists of effluent from the North Side WRP. In this study, multiple samplings of the effluent and stream water were conducted and fish (largemouth bass and carp) were collected on 2 …

Test 1999: John Deere 8335rt, 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 …

Investigating Rfid For Linear Asset Management, Judy A. Perkins Ph.D., P.E., Erick C. Jones Ph.D., P.E., Cssbb, Judith L. Mwakalonge Ph.D., E.I.T

Mid-America Transportation Center: Final Reports and Technical Briefs

A linear asset is defined as an asset whose length plays a critical role in its maintenance. Examples of such assets include roads, pipelines, and railroad tracks. Major features of a roadway asset include traffic lights, number of lanes, speed limits, guardrails, and highway billboards. Linear assets, along with their features, are hard to physically access; therefore, previously captured inventory information files may be inaccurate. To address this problem, some of the transportation agencies are investigating technologies that will assist in solving this asset inventory problem. Radio Frequency Identification (RFID) is a technology that uses communication via radio waves to …

Improving The Freight Transportation Roadway System During Snow Events: A Performance Evaluation Of Deicing Chemicals, Christopher Y. Tuan, Barbara M. Gerbino-Bevins

Mid-America Transportation Center: Final Reports and Technical Briefs

The ability of state DOTs to adequately clear roadways during winter weather conditions is critical for a safe and effective freight transportation system. Variables affecting winter maintenance operations include the type of precipitation, air and pavement temperature, traffic, wind, time of day, day of week, and maintenance equipment. The main objective of this study is to identify the best practices for normal deicing operations, based on the performance rating of deicing chemicals. Optimum deicer/brine ratios and the associated application rates will be determined for various weather conditions. The best practices will ensure effective deicing operation and economical use of deicing …

Impact Of Large 0.7 Inch Strand On Nu-I Girders, Maher K. Tadros Ph.D., P.E., George Morcous Ph.D.

Mid-America Transportation Center: Final Reports and Technical Briefs

The NU I-Girder series uses a unique cross-section and high-strength concrete to achieve longer spans. The objective of this project was to develop the quality control and design criteria required to introduce 0.7 inch strands at 2 in. spacing in NU I-Girders. Compared to 0.5 inch strands, only 1/2 of the total number of strands would be needed. This would result in immediate labor savings in precast concrete product costs. More importantly, having the ability to introduce almost twice the prestressing force, compared to 0.5 inch strands, and 135% of the prestressing force, compared to 0.6 inch strands, could result …

A Framework For The Nationwide Multimode Transportation Demand Analysis, Hojong Baik Ph.D., Yuepeng Cui, Tao Li

Mid-America Transportation Center: Final Reports and Technical Briefs

This study attempts to analyze the impact of traffic on the US highway system considering both passenger vehicles and trucks. For the analysis, a pseudo-dynamic traffic assignment model is proposed to estimate the time-dependent link flow from the intercity travelers on the network covering the continental U.S. A two-stage simulation scheme was designed to separate the intercity and non-intercity travelers involved in the link flow. The fuel consumption and emissions from the intercity travelers are estimated based on data in Mobile, the emission model developed by EPA. The suggested methodology could be adopted in further deployment of a nationwide transportation …

2011 Nebraska Water Monitoring Programs Report, Marty Link

Nebraska Department of Environmental Quality: Reports

The Nebraska Department of Environmental Quality (NDEQ) is charged with monitoring, assessing, and to the extent possible, managing the state’s water resources. The purpose of this work is to protect and maintain good quality water and encourage or execute activities to improve poor water quality. Monitoring is done on the over 18,000 miles of flowing rivers and streams, our greater than 280,000 acres of surface water in lakes and reservoirs, and the vast storage of groundwater in Nebraska’s aquifers.

Structural Capacity Of Steel Tubular Cast-In-Place Piling , Kevin A. Mears

Dissertations, Master's Theses and Master's Reports - Open

Steel tubular cast-in-place pilings are used throughout the country for many different project types. These piles are a closed-end pipe with varying wall thicknesses and outer diameters, that are driven to depth and then the core is filled with concrete. These piles are typically used for smaller bridges, or secondary structures. Mostly the piling is designed based on a resistance based method which is a function of the soil properties of which the pile is driven through, however there is a structural capacity of these members that is considered to be the upper bound on the loading of the member. …

Numerical Study On The Curling And Warping Of Hardened Rigid Pavement Slabs, Qin Yinghong

Dissertations, Master's Theses and Master's Reports - Open

In-service hardened concrete pavement suffers from environmental loadings caused by curling and warping of the slab. Traditionally, these loadings are computed on the basis of treating the slab as an elastic material, and of evaluating separately the curling and warping components. This dissertation simulates temperature distribution and moisture distribution through the slabs by use of a developed numerical model that couples the heat transfer and moisture transport. The computation of environmental loadings treats the slab as an elastic-viscous material, which considers the relaxation behavior and Pickett effect of the concrete.

The heat transfer model considers the impacts of solar radiation, …

Multi-Antenna Non-Line-Of-Sight Identification Techniques For Target Localization In Mobile Ad-Hoc Networks, Wenjie Xu

Dissertations, Master's Theses and Master's Reports - Open

Target localization has a wide range of military and civilian applications in wireless mobile networks. Examples include battle-field surveillance, emergency 911 (E911), traffc alert, habitat monitoring, resource allocation, routing, and disaster mitigation. Basic localization techniques include time-of-arrival (TOA), direction-of-arrival (DOA) and received-signal strength (RSS) estimation. Techniques that are proposed based on TOA and DOA are very sensitive to the availability of Line-of-sight (LOS) which is the direct path between the transmitter and the receiver. If LOS is not available, TOA and DOA estimation errors create a large localization error. In order to reduce NLOS localization error, NLOS identifcation, mitigation, and …

Scanning Capacitance Spectroscopy On N+-P Asymmetrical Junctions In Multicrystalline Si Solar Cells, Chun-Sheng Jiang, Jennifer T. Heath, Helio R. Moutinho, Mowafak M. Al-Jassim

Faculty Publications

We report on a scanning capacitance spectroscopy (SCS) study on the n⁺-p junction of multicrystalline silicon solar cells. We found that the spectra taken at space intervals of ∼10 nm exhibit characteristic features that depend strongly on the location relative to the junction. The capacitance-voltage spectra exhibit a local minimum capacitance value at the electrical junction, which allows the junction to be identified with ∼10-nm resolution. The spectra also show complicated transitions from the junction to the n-region with two local capacitance minima on the capacitance-voltage curves; similar spectra to that have not been previously reported in …

Afit Graduate School Of Engineering And Management Catalog 2011–2012, Graduate School Of Engineering And Management, Air Force Institute Of Technology

AFIT Documents

The Graduate Catalog represents the offerings, programs, and requirements in effect at the time of publication.

A Midsummer Night’S Dream (With Flying Robots), Robin Murphy, Dylan Shell, Amy Guerin, Brittany Duncan, Benjamin Fine, Kevin Pratt, Takis Zourntos

School of Computing: Faculty Publications

Seven flying robot “fairies” joined human actors in the Texas A&M production of William Shakespeare’s A Midsummer Night’s Dream. The production was a collaboration between the departments of Computer Science and Engineering, Electrical and Computer Engineering, and Theater Arts. The collaboration was motivated by two assertions. First, that the performing arts have principles for creating believable agents that will transfer to robots. Second, the theater is a natural testbed for evaluating the response of untrained human groups (both actors and the audience) to robots interacting with humans in shared spaces, i.e., were believable agents created? The production used two types …

Performance Analysis Of Mimo-Sess With Alamouti Scheme Over Rayleigh Fading Channels, Shichuan Ma, Lim Nguyen, Yaoqing Lamar Yang, Won Mee Jang

Department of Electrical and Computer Engineering: Faculty Publications

Self-encoded spread spectrum (SESS) is a novel modulation technique that acquires its spreading sequence from the random input data stream rather than through the use of the traditional pseudo-noise code generator. It has been incorporated with multiple-input multiple-output (MIMO) systems as a means to combat fading in wireless channels. In this paper, we present the analytical study of the bit-error rate (BER) performance of MIMO-SESS systems under Rayleigh fading. The BER expressions are derived in closed form, and the veracity of the analysis is confirmed by numerical calculations that demonstrate excellent agreement with simulation results. The performance analysis shows that …

All-Dielectric Invisibility Cloaks Made Of Batio3-Loaded Polyurethane Foam, Di Bao, Khalid Z. Rajab, Yang Hao, Efthymios Kallos, Wenxuan Tang, Christos Argyropoulos, Yongzhe Piao, Shoufeng Yang

Department of Electrical and Computer Engineering: Faculty Publications

Transformation optics has led the way in the development of electromagnetic invisibility cloaks from science fiction to engineering practice. Invisibility cloaks have been demonstrated over a wide range of the electromagnetic spectrum, and with a variety of different fabrication techniques. However, all previous schemes have relied on the use of metamaterials consisting of arrays of sub-wavelength inclusions. We report on the first cloaking structure made of a high-k dielectric-loaded foam mixture. A polyurethane foam mixed with different ratios of barium titanate is used to produce the required range of permittivities, and the invisibility cloak is demonstrated to work for all …

Energy Efficiency And Goodput Analysis In Two-Way Wireless Relay Networks, Qing Chen, M. Cenk Gursoy

Department of Electrical and Computer Engineering: Faculty Publications

In this paper, we study two-way relay networks (TWRNs) in which two source nodes exchange their information via a relay node indirectly in Rayleigh fading channels. Both Amplify-and-Forward (AF) and Decode-and-Forward (DF) techniques have been analyzed in the TWRN employing a Markov chain model through which the network operation is described and investigated in depth. Automatic Repeat-reQuest (ARQ) retransmission has been applied to guarantee the successful packet delivery. The bit energy consumption and goodput expressions have been derived as functions of transmission rate in a given AF or DF TWRN. Numerical results are used to identify the optimal transmission rates …

Battery Capacity Footprinting And Optimization Analysis For Wireless Multimedia Communication, Jianxin Sun, Dalei Wu, Song Ci

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Micro-electronic industry has been boosting the capability of wireless mobile devices on full-scale. However, battery, as the only power source of most mobile devices, is experiencing a relatively slow development. Therefore, how to optimally utilize the limited battery energy on mobile devices under a predefined performance requirement becomes a critical issue. On the other hand, it is still unclear that how the battery capacity consumption is allocated on different working pattern of a specific video codec under various tempo-spatial scales and parameters, which has posed a design challenge on power management on multimedia communication system. Furthermore, an optimization method is …

Distributed Mimo Technologies In Cooperative Wireless Networks, Shichuan Ma, Yaoqing (Lamar) Yang, Hamid Sharif

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Multiple-input multiple-output techniques enhance wireless communications performance by taking advantage of spatial diversity. However, most traditional MIMO systems hardly achieve large spatial diversity because of limited terminal size. In this article, we present recent advances of the distributed MIMO technologies in cooperative wireless networks. We also compare and discuss various relay protocols and cooperative strategies. Our simulation results indicate that distributed MIMO systems can provide larger spatial diversity, and the data rate in cooperative networks can be significantly increased.

Video Surveillance Over Wireless Sensor And Actuator Networks Using Active Cameras, Dalei Wu, Song Ci, Haiyan Luo, Yun Ye, Haohong Wang

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Although there has been much work focused on the camera control issue on keeping tracking a target of interest, few has been done on jointly considering the video coding, video transmission, and camera control for effective and efficient video surveillance over wireless sensor and actuator networks (WSAN). In this work, we propose a framework for real-time video surveillance with pan-tilt cameras where the video coding and transmission as well as the automated camera control are jointly optimized by taking into account the surveillance video quality requirement and the resource constraint of WSANs. The main contributions of this work are: i) …

Ann-Based Adaptive Pi Control For Wind Turbine With Doubly Fed Induction Generator, Baohua Dong, Sohrab Asgarpoor, Wei Qiao

Department of Electrical and Computer Engineering: Faculty Publications

This paper focuses on developing a novel algorithm which dynamically optimizes the controllers of doubly fed induction generator (DFIG) driven by a wind turbine (WT) to increase DFIG transient performance in all wind speed conditions. Particle swarm optimization (PSO) is proposed to optimize parameters of PI controllers of DFIG’s rotor side/grid side converters (RSC/GSC) at different wind speeds in order to maximize the damping ratios of the system eigenvalues in small signal stability analysis. Based on the optimal values and the wind speed data set, an artificial neural network (ANN) is designed, trained, and it has the ability to quickly …