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Articles 4621 - 4650 of 11222

Full-Text Articles in Engineering

Water Quality Models For Stormwater Runoff In Two Lincoln, Nebraska Urban Watersheds, Jake Fisher Dec 2011

Water Quality Models For Stormwater Runoff In Two Lincoln, Nebraska Urban Watersheds, Jake Fisher

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Water quality monitoring was conducted in two urban watersheds (Colonial Hills and Taylor Park) located in southeast Lincoln, NE over a three year period spanning from October 2008 through September 2011. In-line probes continuously measured for turbidity, conductivity, dissolved oxygen, and water temperature while other water quality constituents were analyzed for discrete water samples collected using grab and automatic sampling techniques. The water quality data was used to calculate event mean concentrations (EMCs) for sixteen storm events sampled over the duration of the project period. Three types of stormwater quality multiple linear regression models were developed for the estimation of …


Optical And Magnetic Properties Of Feni Slanted Columnar Thin Films Infiltrated With Pmma And Fe3O4 Nanoparticles, Dan Liang Dec 2011

Optical And Magnetic Properties Of Feni Slanted Columnar Thin Films Infiltrated With Pmma And Fe3O4 Nanoparticles, Dan Liang

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

In this thesis, dielectric polymer and magnetic nanoparticles were utilized to hybridize FeNi Slanted columnar thin films (SCTFs). Firstly Fe3O4 in PMMA matrix was prepared by physical blending process. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to investigate the dispersion of the nanoparticles in PMMA matrix and the preparation conditions were varied to optimize the dispersion. The hybridized materials were prepared by the infiltration of PMMA and 5 wt% Fe3O4 nanoparticles/PMMA to the voids of FeNi SCTFs. Spin-coating and annealing process were employed to reach an excellent infiltration.

The structural …


Relational Neighborhood Inverse Consistency For Constraint Satisfaction: A Structure-Based Approach For Adjusting Consistency And Managing Propagation, Robert J. Woodward Dec 2011

Relational Neighborhood Inverse Consistency For Constraint Satisfaction: A Structure-Based Approach For Adjusting Consistency And Managing Propagation, Robert J. Woodward

School of Computing: Dissertations, Theses, and Student Research

Freuder and Elfe [1996] introduced Neighborhood Inverse Consistency (NIC) as a local consistency property defined on the values in the variables' domains of a Constraint Satisfaction Problem (CSP). Debruyne and Bessiere [2011] showed that enforcing NIC on binary CSPs is ineffective on sparse graph and too costly on dense graphs. In this thesis, we propose Relational Neighborhood Inverse Consistency (RNIC), an extension of NIC defined as a local consistency property on the tuples of the relations of a CSP. We characterize RNIC for both binary and non-binary CSPs, and propose an algorithm for enforcing it whose complexity is bounded by …


Water Quality Monitoring Of An Urban Stream For Total Maximum Daily Load Assessment, Jeffrey K. Mihulka Dec 2011

Water Quality Monitoring Of An Urban Stream For Total Maximum Daily Load Assessment, Jeffrey K. Mihulka

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The purpose of this research project was to assess the water quality of an urban stream for total maximum daily load assessment in Omaha, Nebraska. This was accomplished by sampling the water quality at four different sites. These sites included sampling upstream, within, and downstream of the city. These samples were conducted throughout 2010 and 2011.

The results showed that concentrations of Escherichia coli (E. coli) are routinely above established criteria for the state of Nebraska. Concentrations of E. coli that exist in the Papillion Creek Watershed upstream of the City of Omaha have also been shown to be above …


Design, Analysis, And Testing Of In Vivo Surgical Robots, Tyler David Wortman Dec 2011

Design, Analysis, And Testing Of In Vivo Surgical Robots, Tyler David Wortman

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Advances in technology have shaped the history of surgical procedures. Recent developments have allowed surgical procedures to become less invasive than traditional open procedures. The transition to Minimally Invasive Surgery (MIS) has resulted in decreased recovery times, improved cosmetic results, and reduced costs. For these reasons, there is interest in further reducing the invasiveness of surgical procedures by accessing the abdominal cavity through a single incision, such as with Laparoendoscopic Single-Site (LESS) surgery. Added complexities, such as unintuitive controls and limited dexterity, prevent the widespread adoption of LESS for complex surgical procedures. Multi-functional in vivo surgical robots have been designed …


Nanoparticle Necklace Network Arrays Exhibiting Room Temperature Single-Electron Switching, Jennifer L. Kane Dec 2011

Nanoparticle Necklace Network Arrays Exhibiting Room Temperature Single-Electron Switching, Jennifer L. Kane

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

A single nanoparticle is one of the most sensitive electronic devices for sensing chemicals in a gas or liquid. The conductivity of a single Au nanoparticle is significantly modulated by the binding of a molecule that alters charge by just one electron. However, the single-electron sensitivity requires cryogenic temperatures and interconnection is not easy. A patterned two-dimensional network of one-dimensional nanoparticle necklaces made up of 10 nm Au particles are fabricated and shown to exhibit similar single-electron effect at room temperature. Furthermore, the long range conductivity of over 10’s of microns makes the structure easy to self-assemble onto conventional microelectronics …


Strength Of Polycrystalline Ceramics Under Shock Compression, Jianbin Zhu Dec 2011

Strength Of Polycrystalline Ceramics Under Shock Compression, Jianbin Zhu

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

Determinations of Some polycrystalline ceramics’ strength properties and inelastic deformation mechanisms in the shocked state are critically important to the design and optimization of armor structures involving these materials. In this work, multiscale modeling and simulations have been carried out to study strength of the effects of polycrystalline microstructure, crystal anisotropy, porosity, and their interactions with microscopic deformation/damage mechanisms on the responses of several polycrystalline ceramics under shock compression and to extract their shock strengths from the wave profiles measured in the related plate impact shock wave experiments.

With a mesoscopic computational model, the roles of intragranular microplasticity and deformation …


Development Of A State Of The Art Traffic Microsimulation Model For Nebraska, Justice Appiah, Bhaven Naik, Laurence Rilett, Yifeng Chen, Seung-Jun Kim Dec 2011

Development Of A State Of The Art Traffic Microsimulation Model For Nebraska, Justice Appiah, Bhaven Naik, Laurence Rilett, Yifeng Chen, Seung-Jun Kim

Nebraska Department of Transportation: Research Reports

No abstract provided.


Evaluation Of Ndor's Actuated Advance Warning Systems, Justice Appiah, Laurence Rilett, Zifeng Wu Dec 2011

Evaluation Of Ndor's Actuated Advance Warning Systems, Justice Appiah, Laurence Rilett, Zifeng Wu

Nebraska Department of Transportation: Research Reports

No abstract provided.


The Effects Of Pedestrian Countdown Timers On Safety And Efficiency Of Operations At Signalized Inersections, Anuj Sharma, Jacob Schmitz Dec 2011

The Effects Of Pedestrian Countdown Timers On Safety And Efficiency Of Operations At Signalized Inersections, Anuj Sharma, Jacob Schmitz

Nebraska Department of Transportation: Research Reports

No abstract provided.


Studies On Power Hop Using A Nonlinear Model Of An Agricultural Tractor, Adam B. Flaugh Dec 2011

Studies On Power Hop Using A Nonlinear Model Of An Agricultural Tractor, Adam B. Flaugh

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Power hop is an unstable dynamic phenomenon that is observed on agricultural tractors operating at field working speeds under typical draft loads. This dynamic instability can be identified as a bounce motion preceded by an increasing oscillation in either the pitch or bounce modes. A definite and comprehensive correction or prevention strategy for the control of power hop does not exist. In this work a linear and a nonlinear model of an agricultural tractor were developed. The method of multiple time scales has been employed in the analysis of the nonlinear model. Numerical results have been obtained using Mathematica to …


The Economics And Logistics Of The Dual Harvest Of Grain And Biomass In A Single-Pass, Matthew T. Wold Dec 2011

The Economics And Logistics Of The Dual Harvest Of Grain And Biomass In A Single-Pass, Matthew T. Wold

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Significant interest has developed in using cellulosic resources, especially crop residues, to create biofuels. Collecting these residues in a single-pass of the harvester across the field has the potential to be a low cost option. Two models have been developed; the first characterizes the in-field logistics of single-pass crop residue collection, the second the economics. These models allow the user to easily examine a wide variety of both grain-only and single-pass residue collection harvest cases. A variety of possible residue collection cases have been examined, and their effects both on harvester field capacity and harvest cost compared to grain-only harvest …


Evaluating The Cost-Effectiveness Of Roadside Culvert Treatments, Francisco Daniel B. De Albuquerque, Dean L. Sicking, Ronald K. Faller, Karla A. Lechtenberg Dec 2011

Evaluating The Cost-Effectiveness Of Roadside Culvert Treatments, Francisco Daniel B. De Albuquerque, Dean L. Sicking, Ronald K. Faller, Karla A. Lechtenberg

Department of Civil and Environmental Engineering: Faculty Publications

Roadside cross-drainage culverts have been found to affect vehicle accident injury levels. As a result, highway designers have commonly used three safety treatments to protect errant motorists from striking culvert openings. These safety treatments have included: culvert extension, guardrail installation, and the application of safety grating. However, the identification of the most appropriate safety treatment for roadside culverts may be challenging; accident costs may dramatically change under different road and traffic characteristics. The purpose of this study was to estimate accident costs for a wide range of road and traffic scenarios and then define the safest treatment (i.e., treatment with …


Detection-Assisted Object Tracking By Mobile Cameras, Li He Dec 2011

Detection-Assisted Object Tracking By Mobile Cameras, Li He

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Tracking-by-detection is a class of new tracking approaches that utilizes recent development of object detection algorithms. This type of approach performs object detection for each frame and uses data association algorithms to associate new observations to existing targets. Inspired by the core idea of the tracking-by-detection framework, we propose a new framework called detection-assisted tracking where object detection algorithm provides help to the tracking algorithm when such help is necessary; thus object detection, a very time consuming task, is performed only when needed. The proposed framework is also able to handle complicated scenarios where cameras are allowed to move, and …


A 2-D Processor Array For Massively Parallel Image Processing, Anantha Krishna Nelliparthi Dec 2011

A 2-D Processor Array For Massively Parallel Image Processing, Anantha Krishna Nelliparthi

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

The concept of introducing image processing logic within the spatial gaps of an array of photodiodes is the key factor behind the presented work. A two-dimensional massively parallel image processing paradigm based on 8X8 pixel neighborhood digital processors has been designed. A low complexity processor array architecture along with its instruction set has been designed and fully verified on a FPGA platform. Various image processing tests have been run on the FPGA platform to demonstrate the functionality of a design that uses 12 parallel processors. The test results indicate that the architecture is scalable to support high frame rates while …


Location Cheating: A Security Challenge To Location-Based Social Network Services, Mai Ren Dec 2011

Location Cheating: A Security Challenge To Location-Based Social Network Services, Mai Ren

School of Computing: Dissertations, Theses, and Student Research

Location-based mobile social network services such as Foursquare and Gowalla have grown exponentially over the past several years. These location-based services utilize the geographical position to enrich user experiences in a variety of contexts, including location-based searching and location-based mobile advertising. To attract more users, the location-based mobile social network services provide real-world rewards to the user, when a user checks in at a certain venue or location. This gives incentives for users to cheat on their locations.

In this thesis, we investigate the threat of location cheating attacks, find the root cause of the vulnerability, and outline the possible …


Sensitivity Analysis On Mapping Evapotranspiration At High Resolution Using Internal Calibration (Metric), Venkata Naga Ravi Kumar Choragudi Dec 2011

Sensitivity Analysis On Mapping Evapotranspiration At High Resolution Using Internal Calibration (Metric), Venkata Naga Ravi Kumar Choragudi

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Mapping EvapoTranspiration at high Resolution using Internal Calibration (METRIC) is most widely used to quantify evapotranspiration (ET) spatially and temporally. It is essential to inspect the model’s response to errors in various parameters used in the model. Landsat 5 images from May 30 2009, July 1 2009 and a Landsat 7 image from September 27 2009 are used in this study. Fourteen different fields composed of Corn, Soybeans, Alfalfa are randomly chosen for each crop type.

Two kinds of errors are addressed in this study. One, with the errors that are transferred and potentially compensated by calibration (Global error) and …


Development Of A Design Procedure For Concrete Traffic Barrier Attachments To Bridge Decks Utilizing Epoxy Concrete Anchors, Benjamin J. Dickey Dec 2011

Development Of A Design Procedure For Concrete Traffic Barrier Attachments To Bridge Decks Utilizing Epoxy Concrete Anchors, Benjamin J. Dickey

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

A guide for the design of epoxy anchors for the use in concrete traffic barriers was developed in this study. A series of dynamic bogie tests and static tests was conducted on single and double anchors. The dynamic increase factor for the noted anchors was determined to be 1.06. Protective epoxy coatings for the anchors was observed to contribute to a 9 percent decrease in anchorage strength. The effects of anchors located in close proximity to each other was also investigated. Calibration factors were developed to apply recommended changes to the ACI code for use in bridge rail anchorages.

A …


Expanding The Length Of Jointless Bridges By Providing Rotational Capacity Over The Pile Head, Ardalan Sherafati Dec 2011

Expanding The Length Of Jointless Bridges By Providing Rotational Capacity Over The Pile Head, Ardalan Sherafati

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Jointless bridges have been in service for more than 50 years. Since no expansion joint is utilized in these structures, they have longer service life, reduced maintenance and construction costs, improved riding quality, and added redundancy. Because of integrity of the superstructure with the substructure, the thermal movements as well as other longitudinal movements are transferred to substructure. These lateral movements can induce relatively large forces and moments in the substructure elements including the abutment and the piles. Typically, flexible foundations which include single row of piles are preferred in jointless bridges to reduce the stiffness of the system against …


A Novel Telecommunications-Based Approach To Mathematical Modeling Of Hiv Infection, Aaron T. Sharp Dec 2011

A Novel Telecommunications-Based Approach To Mathematical Modeling Of Hiv Infection, Aaron T. Sharp

Department of Computer Electronics and Engineering: Dissertations, Theses, and Student Research

It is well known that biological systems utilize communication in some form, one prolific example of this is the propagation of HIV (Human Immunodeficiency Virus) in the human body. By modeling HIV infection as a communication system, we hope to gain a unique insight into HIV and biological communication systems in general. Such a model would provide researchers a platform for experimenting and simulating various biological communication systems. We have previously developed a layered communication protocol for interpreting biological communication systems using telecommunications paradigms and will apply said model to HIV proliferation. We will also demonstrate the effectiveness of the …


Hydrologic Evaluation Of Established Rain Gardens In Lincoln, Nebraska Using A Storm Runoff Simulator, Andrew R. Anderson Dec 2011

Hydrologic Evaluation Of Established Rain Gardens In Lincoln, Nebraska Using A Storm Runoff Simulator, Andrew R. Anderson

Department of Environmental Engineering: Theses and Other Student Research

Increased urbanization has resulted in water quality and flooding problems for many receiving waters in the United States. Bioretention, or rain gardens, is one of the most widely popular and effective best management practices in low impact development (LID), which strives to return a watershed to a predevelopment hydrologic regime. Many studies have evaluated large bioretention cells in research settings. There is little information on the effectiveness of homeowner-maintained rain gardens that rely on deep percolation as the method for water exfiltration. Additionally, few studies address rain garden performance in cold, arid, or semi-arid climates found in the Midwest U.S. …


Economic Analysis Of Continuous Monitoring Of Commercial Truck Tire Pressure Using Tire Pressure Monitoring Systems (Tpms) And Rfid Technologies, Afolabi A. Ogunwemimo Dec 2011

Economic Analysis Of Continuous Monitoring Of Commercial Truck Tire Pressure Using Tire Pressure Monitoring Systems (Tpms) And Rfid Technologies, Afolabi A. Ogunwemimo

Department of Industrial and Management Systems Engineering: Dissertations, Theses, and Student Research

The trucking industry is a major contributor to the US economy. By providing the essential services of transportation and distribution needed in today’s dynamic industry, the transportation industry has evolved into an integral player in various supply chains. The trucking industry is the largest transportation provider for other industries and employs 10.1 million workers in the United States (ATA, 2003).

This research is an analysis of the economic impact of maintaining proper air pressure in the tires of commercial trucks. Various studies have been carried out on understanding the relationship between tire pressure and fuel consumption (National Research Council, 2006). …


Feasibility Analysis And Concept Development Of A Crash Cushion Diaphragm Structure For High-Speed Race Tracks, Curt Lee Meyer Dec 2011

Feasibility Analysis And Concept Development Of A Crash Cushion Diaphragm Structure For High-Speed Race Tracks, Curt Lee Meyer

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

A new diaphragm and dual guide rail system was designed for use in a crash cushion for high-speed race tracks. These structural components were designed to provide sufficient lateral support to redirect impacting vehicles and compress the energy-absorbing elements of the crash cushion. The primary design criteria stated that the diaphragm/guide rail system should be capable of withstanding a 100-kip lateral impact load. The guide rail was to be configured in order to not require replacement after a design impact event. Initial design and modeling resulted in two candidates for guide rail sections which were evaluated during physical testing. The …


In-Situ Ellipsometry Characterization Of Anodically Grown Silicon Dioxide And Lithium Intercalation Into Silicon, Eric A. Montgomery Nov 2011

In-Situ Ellipsometry Characterization Of Anodically Grown Silicon Dioxide And Lithium Intercalation Into Silicon, Eric A. Montgomery

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

In this thesis, in-situ ellipsometry and electroanalytical investigations of two electrochemical processes are reported: including the formation of anodically grown silicon dioxide and the intercalation of lithium into silicon. Analysis of the ellipsometry data shows that the anodically grown silicon dioxide layer is uniform and has similar properties as thermally grown silicon dioxide. The lithium-ion intercalation data reveals non-uniform thin film formation, which requires further studies and development of appropriate ellipsometric optical models.

Advisers: Eva Schubert and Mathias Schubert


Wim Based Load Models For Bridge Serviceability Limit States, Przemyslaw Rakoczy Nov 2011

Wim Based Load Models For Bridge Serviceability Limit States, Przemyslaw Rakoczy

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The safety of aging bridge inventory is one of the main concerns of the state and federal agencies. Therefore, there is a need to quantify the safety margin of existing infrastructure and new design bridges. The Serviceability Limit States, i.e. fatigue, requires additional statistical parameters and not only the maximum values but also load spectra, i.e. frequency of occurrence of loads. The maximum values are needed for shorter time periods, such as day, week, month or year. Load spectra as well as material resistance are random variables. To quantify the safety margin of existing and future bridges load and resistance …


Efficient Traffic Crash And Snow Complaint Gis System, Anthony B. Ngo Nov 2011

Efficient Traffic Crash And Snow Complaint Gis System, Anthony B. Ngo

School of Computing: Dissertations, Theses, and Student Research

We describe the design and implementation of a traffic crash and snow complaint GIS system developed for the Lincoln Public Works department. We also describe a novel geocoding algorithm that was used to move data from the older Criminal Justice Information System, which is a relational database, to the new GIS system. In addition, we describe the implementation of several indexing algorithms that enable the system to efficiently answer rectangular range queries and queries about the relative locations of moving objects. Finally, in many applications (on-line analysis or mobile GIS), we need to execute spatial query efficiently (fast and small), …


Electronic Monitoring Of Hand Hygiene Compliance In An Inpatient Hospital Setting, Christopher M. Masek Nov 2011

Electronic Monitoring Of Hand Hygiene Compliance In An Inpatient Hospital Setting, Christopher M. Masek

Department of Industrial and Management Systems Engineering: Dissertations, Theses, and Student Research

Proper hand hygiene is known to reduce hospital acquired infections. Currently the most widely accepted method used to measure hand hygiene compliance is through direct observation. This method often provides data that may not accurately represent true hand hygiene compliance due to such factors such as the Hawthorne Effect. Perhaps a better approach is to use counting devices to capture hand hygiene opportunities and activities. This thesis focuses on the measurement of hand hygiene activities of all individuals that either work or visit an inpatient medical ward including healthcare workers, patients and visitors at the patient’s bedside for non-isolation patients. …


Power Control And Security Games For Wireless Communication Networks, Bo Liang Nov 2011

Power Control And Security Games For Wireless Communication Networks, Bo Liang

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

In this thesis, game theoretic analysis of wireless communication networks has been performed. Game theory provides valuable tools can be used to solve problem of conflict and cooperation in wireless communication networks. Game theoretic tools can be applied to multiple layers of wireless networks. First, we consider power control issues at the physical layer of wireless networks. A game theoretic analysis for resource allocation policies in fading interference channels in the presence of quality of service (QoS) constraints is performed. We model a two player non-cooperative power control game and assume that both transmitters and receivers know the channel side …


Acuta Enews November 2011, Vol 40, No. 11 Nov 2011

Acuta Enews November 2011, Vol 40, No. 11

ACUTA Newsletters

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Committee Corner

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Member Benefit of the Month: Member Logos

Thanks to Exhibitors and Sponsors at Fall Seminar

A University in your pocket: Education and Mobile Devices …


The Genome Portal Of The Department Of Energy Joint Genome Institute, Igor V. Grigoriev, Henrik Nordberg, Igor Shabalov, Andrea Aerts, Mike Cantor, David Goodstein, Alan Kuo, Simon Minovitsky, Roman Nikitin, Robin A. Ohm, Robert Otillar, Alex Poliakov, Igor Ratnere, Robert Riley, Tatyana Smirnova, Daniel Rokhsar, Inna Dubchak Nov 2011

The Genome Portal Of The Department Of Energy Joint Genome Institute, Igor V. Grigoriev, Henrik Nordberg, Igor Shabalov, Andrea Aerts, Mike Cantor, David Goodstein, Alan Kuo, Simon Minovitsky, Roman Nikitin, Robin A. Ohm, Robert Otillar, Alex Poliakov, Igor Ratnere, Robert Riley, Tatyana Smirnova, Daniel Rokhsar, Inna Dubchak

United States Department of Energy: Publications

The Department of Energy (DOE) Joint Genome Institute (JGI) is a national user facility with massive-scale DNA sequencing and analysis capabilities dedicated to advancing genomics for bioenergy and environmental applications. Beyond generating tens of trillions of DNA bases annually, the Institute develops and maintains data management systems and specialized analytical capabilities to manage and interpret complex genomic data sets, and to enable an expanding community of users around the world to analyze these data in different contexts over the web. The JGI Genome Portal (http://genome.jgi.doe.gov) provides a unified access point to all JGI genomic databases and analytical tools. A user …