Engineering Commons^™

Development Of Alternative Wood-Post Mgs Approach Guardrail Transition, Scott K. Rosenbaugh, Kevin D. Schrum, Ronald K. Faller, Karla A. Lechtenberg, Dean L. Sicking, John D. Reid

Nebraska Department of Transportation: Research Reports

No abstract provided.

Thermodynamics Of Magnetic Multilayers, Tathagata Mukherjee

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

Our interest in thermodynamics of magnetic thin film heterostructure began by exploring the possibility to use magnetic nanostructures in the search for optimized magnetocaloric materials for potential room temperature refrigeration. In the present thesis magnetic thin film heterostructures are experimentally realized by Molecular Beam Epitaxy (MBE) and Pulsed Laser Deposition (PLD). Co/Cr and Fe/Cr superlattices were fabricated using mean-field theoretical concepts as guiding principles. The potential of artificial antiferromagnets for near room-temperature refrigeration is explored. Magnetocaloric properties are deduced from measurements of the temperature and field dependence of the magnetization of our samples. The effects of intra-plane and inter-plane exchange …

Simulation And Fabrication Of 3d Spiral Photonic Crystals As Circular Polarizers, Xuejian Li

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

Three-dimensional (3D) spiral photonic crystals (PhCs) have a periodic varied refractive index (RI) with the periodicity comparable to the wavelength of incident light. They can pass circularly polarized (CP) light with handedness opposite to their own structures’ handedness while block the polarization state with the same handedness. Three-dimensional spiral PhCs for use as circular polarizers have two main advantages over conventional circular polarizers. On the one hand, it has wide operation wavelength based on the photonic band gap caused by PhCs and the interaction between CP light and each individual spiral structure. On the other hand, the height of each …

Extending Integral Concepts To Curved Bridge Systems, Saeed Eghtedar Doust

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

The behavior of integral abutment systems and the extension of their application to curved bridges are investigated. First, the stresses in the elements of a typical integral abutment are studied by conducting nonlinear finite element analysis using the software package Abaqus. The results are design recommendations for the details of such abutments. The effect of integral abutments on the responses of bridges is also investigated. Steel and concrete bridge systems are studied separately.

The studied steel bridge systems are composed of composite I-girder superstructures and integral abutments supported on steel H-piles. A series of finite element studies for different bridge …

Seamless Bridge And Roadway System For The U.S. Practice, Nima Ala

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

Expansion joints are one of the main causes for high maintenance costs in bridges. The search for ideal expansion joints has proven fruitless. That is why it has been said that “the best joint is no joint”. A seamless bridge system is envisioned that results in bridges with long service lives by eliminating the joints over the entire length of the bridge, approach slab and a segment of the roadway called transition. All bridge thermal movements are dissipated to zero in the transition. The system is similar to a system developed in Australia but modifications had to be made to …

History Of The Biological Systems Engineering Program In Nebraska, University Of Nebraska-Lincoln, William E. Splinter

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The Farm Machinery/Agricultural Engineering/Biological Systems Engineering program current and former faculty members at the University of Nebraska, as demonstrated here, has made a statewide, national, and worldwide impact on the efficient production of food. The quality of this recognition is evidenced best by peer professionals through recognized ASABE awards received by Nebraska alumni or professors. Since its inception in 1909 and until 2010, there have been 10 national presidents, 19 gold medal recipients and 33 named national award recipients. Currently there are 31 ASABE Fellows and two members of the National Academy of Engineering. This national recognition comes as a …

Acuta Enews October 2011, Vol 40, No. 10

ACUTA Newsletters

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Nominate Now for 2012-2013 Board of Directors

Corinne Hoch Named Executive Director

Define Your Expectations to Vendors ......Ron Walczak, Walczak Technology Consultants

Additional Guidance on Taxation of Employer-Provided Cell Phones.......Michael Hepburn, Dow Lohnes

Institutional Excellence Award 2012

From ACUTA Headquarters: Looking Back to the Future.......... Corinne Hoch, Executive Director

Board Report.......... Riny Ledgerwood, SDSU

lnfo Links .,......... .. Randy Hoyes, Univ. of Northern lowa

Committee Corner

Get Your Logos Here!

Documenting the Worth of an lT Degree

Member Benefit of the Month: ACUTA Community

Welcome New Members

Check lt Out: Press Releases...Job Postings...RFls/RFPs...Special Deals!...Corporate Webinars

Nebraska Blueprint – Fall/Winter 2011

Nebraska Blueprint (Student Publication)

Table of Contents:

From the Editor

Engi-Briefs

Dean Tim Wei and the Future of Nebraska Engineering

Researching Safety on the Highway – "Cody S. Stolle, a graduate research assistant at UNL's Midwest Roadside Safety Facility, recently conducted research on cable median wires to reduce the number of deadly car highway accidents."

Husker Alum Returns – Dr. Kim Blair, Mechanical Engineering alumnus, spoke as part of the Pierson Lecture Series on innovation and technology development.

Engineering Off the Road – UNL's Baja SAE [Society of Automotive Engineers] team placed 3rd in suspension and traction, 7th in tractor pull, 11th in maneuverability, …

Thickness-Shear And Thickness-Twist Vibrations Of An At-Cut Quartz Mesa Resonator, Huijing He, Jinxi Liu, Jiashi Yang

Department of Mechanical and Materials Engineering: Faculty Publications

We study thickness-shear and thickness-twist vibrations of an AT-cut quartz plate mesa resonator with stepped thickness. The equations of anisotropic elasticity are used with the omission of the small elastic constant c56. An analytical solution is obtained using Fourier series from which the resonant frequencies, mode shapes, and energy trapping are calculated and examined. The solution shows that a mesa resonator exhibits strong energy trapping of thickness-shear and thickness-twist modes, and that the trapping is sensitive to some of the structural parameters of the resonator.

Model For Predicting The Impact Upon Economic Development Resulting From Highway Improvement Projects, Eric Thompson, Kanou Comlavi, Mallory Dimmit

Nebraska Department of Transportation: Research Reports

The Nebraska Department of Roads (NDOR) has an interest in integrating state economic development impact as another factor in prioritizing transportation investments. Such efforts require the development of a comprehensive model that can be used to estimate a consistent final measure of economic development impact that can be readily integrated into existing prioritization formulas. This report summarizes the efforts of the University of Nebraska-Lincoln Bureau of Business Research (UNL-BBR) to develop such a model, by measuring the impact of expressway, viaduct, and other major investments projects around the state. Specifically, UNL-BBR developed an economic model to predict the economic impact …

In Vivo Three-Dimensional Blood Velocity Profile Shapes In The Human Common, Internal, And External Carotid Arteries, Alexey Kamenskiy, Yuris A. Dzenis, Jason N. Mactaggart, Anastasia Desyatova, Iraklis I. Pipinos

Department of Mechanical and Materials Engineering: Faculty Publications

Objective: True understanding of carotid bifurcation pathophysiology requires a detailed knowledge of the hemodynamic conditions within the arteries. Data on carotid artery hemodynamics are usually based on simplified, computer-based, or in vitro experimental models, most of which assume that the velocity profiles are axially symmetric away from the carotid bulb. Modeling accuracy and, more importantly, our understanding of the pathophysiology of carotid bifurcation disease could be considerably improved by more precise knowledge of the in vivo flow properties within the human carotid artery. The purpose of this work was to determine the three-dimensional pulsatile velocity profiles of human carotid arteries. …

Climate Change Policy Could Make Keystone Xl Obsolete, Adam Liska

Adam Liska Papers

Clearly the Keystone XL pipeline threatens both surface and ground water that sustains the agricultural economy of Nebraska, but the projected profitability of tar sands oil and the pipeline operation are dependent on the future economics of climate change. Three recent scientific studies estimate the total carbon intensity of tar sands-based gasoline from Alberta (from both production and burning of the fuel) at an average of roughly 22 percent higher than U.S. gasoline in 2005, with the range of average carbon intensities for tar sands-gasoline at 16 to 27 percent higher than most other sources.

Isotope Identification And Source Directional Determination Using Gamma Radiation Profiling, Christopher L. Schrage

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

This thesis presents a method for evaluating gamma radiation profiles using a low power gamma radiation detector system (GRDS). This method enables multiple radioactive gamma isotopes to be identified and determine the respective vector directions of those sources relative to the GRDS location. This detection method must be accurate, implemented as a handheld or fixed solution, and have a suitable battery life for a variety of industrial needs.

This paper will first explain the low power GRDS that was used for developing these detection methods. The target gamma isotopes that are used for validating these methods will be described along …

Stage-Dependent Transient Storage Of Phosphorus In Alluvial Floodplains, Derek M. Heeren, Garey A. Fox, Ronald B. Miller, Daniel E. Storm, Amanda K. Fox, Chad J. Penn, Todd Halihan, Aaron R. Mittelstet

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Models for contaminant transport in streams commonly idealize transient storage as a well-mixed but immobile system. These transient storage models capture rapid (near-stream) hyporheic storage and transport, but do not account for large-scale, stage-dependent interaction with the alluvial aquifer. The objective of this research was to document transient storage of phosphorus (P) in coarse gravel alluvium potentially influenced by large-scale, stage-dependent preferential flow pathways (PFPs). Long-term monitoring was performed at floodplain sites adjacent to the Barren Fork Creek and Honey Creek in northeastern Oklahoma. Based on results from subsurface electrical resistivity mapping which was correlated to hydraulic conductivity data, observation …

Low Complexity Feature Extraction For Classification Of Harmonic Signals, Peter William

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

In this dissertation, feature extraction algorithms have been developed for extraction of characteristic features from harmonic signals. The common theme for all developed algorithms is the simplicity in generating a significant set of features directly from the time domain harmonic signal. The features are a time domain representation of the composite, yet sparse, harmonic signature in the spectral domain.The algorithms are adequate for low-power unattended sensors which perform sensing, feature extraction, and classification in a stand-alone scenario. The first algorithm generates the characteristic features using only the duration between successive zero-crossing intervals. The second algorithm estimates the harmonics’ amplitudes of …

Acuta Enews September 2011, Vol 40, No. 9

ACUTA Newsletters

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Hurricane lrene Takes Top Priority for Some

From the President: ACUTA: A Career Development Program Joe Harrington, Boston College

To Attract Top lT Talent, Understand Graduates' Needs

You Don't Have to Be Young to Be "Young"............. Emily Harris, Vassar College

Add Names from Your Campus to Your ACUTA Roster

Freed-Hardeman Students Develop iPhone App

Announcing member Benefit of the Month

lnfo Links ..........Randy Hayes, Univ. of Northern lowa

Retirement

Committee Corner

ACUTA Fall Seminar in Boston

ACUTA Webinar: Transitioning to lPv6 on Your Campus

Board Report..................Riny Ledgerwood, San Diego state univ

Welcome New Members

Check lt Out: …

Bioenergy Feedstock-Specific Enrichment Of Microbial Populations During High-Solids Thermophilic Deconstruction, Amitha P. Reddy, Martin Allgaier, Steven W. Singer, Terry C. Hazen, Blake A. Simmons, Philip Hugenholtz, Jean S. Vandergheynst

United States Department of Energy: Publications

Thermophilic microbial communities that are active in a high-solids environment offer great potential for the discovery of industrially relevant enzymes that efficiently deconstruct bioenergy feedstocks. In this study, finished green waste compost was used as an inoculum source to enrich microbial communities and associated enzymes that hydrolyze cellulose and hemicellulose during thermophilic high-solids fermentation of the bioenergy feedstocks switchgrass and corn stover. Methods involving the disruption of enzyme and plant cell wall polysaccharide interactions were developed to recover xylanase and endoglucanase activity from deconstructed solids. Xylanase and endoglucanase activity increased by more than a factor of 5, upon four successive …

Performance Analysis Of Cognitive Radio Systems Under Qos Constraints And Channel Uncertainty, Sami Akin, Mustafa Cenk Gursoy

Department of Electrical and Computer Engineering: Faculty Publications

In this paper, performance of cognitive transmission over time-selective flat fading channels is studied under quality of service (QoS) constraints and channel uncertainty. Cognitive secondary users (SUs) are assumed to initially perform channel sensing to detect the activities of the primary users, and then attempt to estimate the channel fading coefficients through training. Energy detection is employed for channel sensing, and different minimum mean-square-error (MMSE) estimation methods are considered for channel estimation. In both channel sensing and estimation, erroneous decisions can be made, and hence, channel uncertainty is not completely eliminated. In this setting, performance is studied and interactions between …

Mimo Wireless Communications Under Statistical Queueing Constraints, M. Cenk Gursoy

Department of Electrical and Computer Engineering: Faculty Publications

The performance of multiple-input multiple-output (MIMO) wireless systems is investigated in the presence of statistical queueing constraints. Queuing constraints are imposed as limitations on buffer violation probabilities. The performance under such constraints is captured through the effective capacity formulation. A detailed analysis of the effective capacity is carried out in the low-power, wideband, and high signal-to-noise ratio (SNR) regimes. In the low-power analysis, expressions for the first and second derivatives of the effective capacity with respect to SNR at SNR = 0 are obtained under various assumptions on the degree of channel state information at the transmitter. Transmission strategies that …

Numerical Modeling Of Steady Burning Characteristics Of Spherical Ethanol Particles In A Spray Environment, Vaibhav Kumar Sahu, Vasudevan Raghavan, Daniel N. Pope, George Gogos

Department of Mechanical and Materials Engineering: Faculty Publications

A numerical study of steady burning of spherical ethanol particles in a spray environment is presented. A spray environment is modeled as a high temperature oxidizer stream where the major products of combustion such as carbon dioxide and water vapor will be present along with reduced amounts of oxygen and nitrogen. The numerical model, which employs variable thermophysical properties, a global single-step reaction mechanism, and an optically thin radiation model, has been first validated against published experimental results for quasi-steady combustion of spherical ethanol particles. The validated model has been employed to predict the burning behavior of the ethanol particle …

Increased Efficiency Of Low Band Gap Polymer Solar Cells At Elevated Temperature And Its Origins, Bin Yang, James Cox, Yongbo Yuan, Fawen Guo, Jinsong Huang

Department of Mechanical and Materials Engineering: Faculty Publications

Photovoltaic characteristics of a low bandgap polymer, poly[(4,4′-bis(2-lethylhexyl)dithieno-[3,2-b:2′,3′-d]silole)-2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl], based bulk hetero-junction organic photovoltaic were investigated from room temperature (RT) to 145 °C to evaluate its applications in harsh environments. The power conversion efficiency was found to increase from 4.1% at RT to 4.5% at 105 °C with increased short circuit current density (J_sc) and fill factor (FF) despite the decreased open circuit voltage (V_oc). Detailed investigation revealed that J_sc and FF improvements were caused by the increased and balanced carrier mobilities at higher temperatures. The V_oc of the low bandgap …

Secure Wireless Communication And Optimal Power Control Under Statistical Queueing Constraints, Deli Qiao, M. Cenk Gursoy, Senem Velipasalar

Department of Electrical and Computer Engineering: Faculty Publications

In this paper, secure transmission of information over fading broadcast channels is studied in the presence of statistical queueing constraints. Effective capacity is employed as a performance metric to identify the secure throughput of the system, i.e., effective secure throughput. It is assumed that perfect channel side information (CSI) is available at both the transmitter and the receivers. Initially, the scenario in which the transmitter sends common messages to two receivers and confidential messages to one receiver is considered. For this case, the effective secure throughput region, which is the region of constant arrival rates of common and …

Synthesis And Characterization Of Highly Textured Pt–Bi Thin Films, Xingzhong Li, Parashu Kharel, Shah R. Valloppilly, David J. Sellmyer

Nebraska Center for Materials and Nanoscience: Faculty Publications

Pt–Bi films were synthesized on glass and thermally oxidized silicon substrates by e-beam evaporation and annealing. The structures were characterized using X-ray diffraction (XRD) and transmission electron microscopy/selected area electron diffraction (TEM/SAED) techniques. Single-phase PtBi was obtained at an annealing temperature of 300°C, whereas a higher annealing temperature of 400°C was required to obtain the highly textured γ-PtBi2 phase. TEM/SAED analysis showed that the films annealed at 400°C contain a dominant γ-PtBi2 phase with a small amount of β-PtBi2 and α-PtBi2 phases. Both the PtBi and γ-PtBi2 phases are highly textured in these two kinds of film: the c-axis of …

Rehabilitation And Exercise Machine, Judith M. Burnfield, Yu Shu, Adam P. Taylor, Thad W. Buster, Carl Nelson

Department of Mechanical and Materials Engineering: Faculty Publications

An improved rehabilitation and exercise machine is provided which allows a person with physical limitations, disabilities or chronic conditions to use the machine in order to rehabilitate their muscles, improve joint flexibility, and enhance cardiovascular fitness.

Acuta Enews August 2011, Vol 40, No. 8

ACUTA Newsletters

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From ACUTA Headquarters.......... Corinne Hoch, lnterim Executive Director

Hosted/Cloud Provider Checklist .Gary Audin, Delphi, lnc.

ACUTA Webinar: Transitioning to lPv6 on Your Campus

Connecting in the Digital Age............. . Buck Bayliff, PCR

Campus Tech a Top Factor in College Selection and Perceived Career Success

lnfo Links ........... .. Randy Hayes, Univ. of Northern lowa

View 8 Sessions from the Summer Seminar at Your Desktop

Come to Boston!

Board Report......... Riny Ledgerwood, SDSU

Welcome New Members

Check lt Out: press Releases...Job Postings.,.RFls/RFPs...Special Deals!...Corporate Webinars

A Cross-Layer Design For The Performance Improvement Of Real-Time Video Transmission Of Secondary Users Over Cognitive Radio Networks, Haiyan Luo, Song Ci, Dalei Wu

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

Cognitive radio (CR) has been proposed as a promising solution to improve connectivity, self-adaptability, and efficiency of spectrum usage. When used in video applications, user-perceived video quality experienced by secondary users is a very important performance metric to evaluate the effectiveness of CR technologies. However, most of the current research only considers spectrum utilization and effectiveness at medium access control (MAC) and physical layers, ignoring the system performance of the upper layers. Therefore, in this paper, we aim to improve the user experience of secondary users for wireless video services over CR networks. We propose a quality-driven cross-layer optimized system …

Articulated Mechanism Design And Kinematics For Natural Orifice Translumenal Endoscopic Surgery Robot, Wei Jian Chin

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

Natural Orifice Translumenal Endoscopic Surgery (NOTES) is a fairly recent surgical approach that eliminates the need for external incisions on the patient. NOTES takes the minimally invasive surgery paradigm a step further by using a natural orifice as the pathway to transport surgical tools to the surgical site and completely eliminating the need for even the smallest incision on the skin. Although the concept of NOTES has been in existence for the past decade, technological deficiencies prevent it from being widely accepted in human surgeries. A novel multifunctional robot for NOTES has been developed to overcome these limitations and make …

Classification For Mass Spectra And Comprehensive Two-Dimensional Chromatograms, Xue Tian

School of Computing: Dissertations, Theses, and Student Research

Mass spectra contain characteristic information regarding the molecular structure and properties of compounds. The mass spectra of compounds from the same chemically related group are similar. Classification is one of the fundamental methodologies for analyzing mass spectral data. The primary goals of classification are to automatically group compounds based on their mass spectra, to find correlation between the properties of compounds and their mass spectra, and to provide a positive identification of unknown compounds.

This dissertation presents a new algorithm for the classification of mass spectra, the most similar neighbor with a probability-based spectrum similarity measure (MSN-PSSM). Experimental results demonstrate …

Effectiveness Study Of Non-Nuclear Gauge For Hot Mix Asphalt (Hma) Pavement Construction, Ziqing Zhuang

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

Density is an important measure for hot-mix asphalt (HMA) pavement quality control. Traditionally, the nuclear gauge method is widely used in pavement density testing. However, some disadvantages of nuclear gauges (such as the handling, storage, and transportation of radioactive materials) have created the need of non-nuclear technology. This thesis evaluated the Pavement Quality Indicator (PQI) model 301, which was promised to be more efficient than the nuclear method. The PQI utilizes many electrical impedance principles by using the current going through the pavement to determine its density and moisture content. Test data were collected in the field during pavements, and …

Effectiveness Study On Temporary Pavement Marking Removals Methods, Koudous Kabassi

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

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 and results-oriented effective compared to other methods, but it was also safe to the environment and road users. Finally, a baseline of measurements was developed for this project, along with the feasibility of …