Engineering Commons^™

Performance Evaluation Of Brass Breakaway Couplings, Joseph G. Putjenter, Scott K. Rosenbaugh, Karla A. Lechtenberg, Ronald K. Faller, Dean L. Sicking, John D. Reid

Nebraska Department of Transportation: Research Reports

No abstract provided.

Layer Moduli Of Nebraska Pavements For The New Mechanistic Empirical Pavement Design Guide, Soohyok Im, Yong-Rak Kim, Hoki Ban

Nebraska Department of Transportation: Research Reports

No abstract provided.

A Methodology For Implementing Rf Bists In Production Testing To Replace Rf Conventional Tests, Deepa Mannath

Graduate Theses and Dissertations

Production testing of Radio Frequency (RF) devices is challenging due to the complex nature of the tests that have to be performed to verify functionality. In this dissertation a methodology to replace the complex and expensive RF functional tests with defect-oriented Built-in Self Tests (BiSTs) is detailed. If a design has sufficient margin to RF specifications then RF tests can be replaced with structural tests using a new data analysis technique called quadrant analysis, which is presented. Data from the analysis of over one million production units of said System on Chip (SoC) is presented along with the results of …

Multi-Threshold Cmos Circuit Design Methodology From 2d To 3d, Ross Josiah Thian

Graduate Theses and Dissertations

A new and exciting approach in digital IC design in order to accommodate the Moore's law is 3D chip stacking. Chip stacking offers more transistors per chip, reduced wire lengths, and increased memory access bandwidths. This thesis demonstrates that traditional 2D design flow can be adapted for 3D chip stacking. 3D chip stacking has a serious drawback: heat generation. Die-on-die architecture reduces exposed surface area for heat dissipation. In order to reduce heat generation, a low power technique named Multi-Threshold CMOS (MTCMOS) was incorporated in this work. MTCMOS required designing a power management unit (to control when and which gates …

Characterization And Evaluation Of A Novel Tissue Engineered Aortic Heart Valve Construct, Mary Tedder

All Dissertations

Tissue engineering holds great promise for treatment of valvular diseases. Scaffolds for engineered heart valves must function immediately after implantation, but must also permit repopulation with autologous host cells and facilitate gradual remodeling.
Native aortic heart valves are composed of three layers, i.e. two strong external fibrous layers (ventricularis and fibrosa) separated by a central, highly hydrated spongiosa. The fibrous layers provide strength and resilience while the spongiosa layer facilitates shearing of the external layers. Our working hypothesis is that partially cross-linked collagen scaffolds that closely mimic the layered histo-architecture of the native valve would fulfill these requirements. To test …

Sensitivity Analysis Of Uranium Speciation Modeling In Groundwater Systems With A Focus On Mobility, Andrew Scott

All Dissertations

Uranium is an important natural resource used in production of nuclear reactor fuel and nuclear weapons. The mining and processing of uranium has left a legacy of environmental contamination that remains to be addressed. There has been considerable interest in manipulating the oxidation state of uranium in order to put it into an environmentally immobile form. Uranium forms two stable oxidation states in nature, uranium (IV) being much less soluble than uranium (VI), and therefore the preferred state with regard to limiting the potential exposure of man. One of the tools used in evaluating potential effects of manipulating the natural …

A Meta-Analysis Of Human Factors Analysis And Classification System Causal Factors: Establishing Benchmarking Standards And Human Error Latent Failure Pathway Associations In Various Domains, Katherine Berry

All Dissertations

Many models of accident investigation have been created and have served as the basis for other tools and techniques. One of the most prominent techniques, Reason's Swiss Cheese Model (1990), is based on the idea of active and latent failures. Expanding on this idea, the Human Factors Analysis and Classification System (HFACS) was created with the idea to associate contributing factors and errors (Wiegmann & Shappell, 2003).
While HFACS has been frequently applied in the field of aviation in literature, other industry types are under-represented. Seventeen data sources encompassing various industry types were collected and included in this dissertation analysis. …

Effect Of Temperature And Pressure On The Densification Of Titanium Silicide Compound, P Thapnuy, S Larpkiattaworn, T Luangvaranunt, J Ikeuchi

Journal of Metals, Materials and Minerals

Titanium silicide compound was synthesized from the mixture of titanium and silicon powder with atomic ratios of 60:40 and 70:30. The powders were mixed by ball milling and pressed by different methods: by using uniaxial pressing at 64 MPa, cold isostatic pressing (CIP) at 200 MPa, hot forging (HF) at 648 MPa, and hot pressing (HP) at 24 MPa. The samples were then sintered at 1300o C or 1600o C for 2 hours soaking time in argon atmosphere. The sintered samples were subsequently characterized for phase constitution using X-ray diffraction (XRD). Ti5Si3 was observed as main compound of mixtures with …

Effects Of Aluminium On Sintered Properties Of Cu-10wt%Sn Bearing, V Chobaomsup, T Luangvaranunt

Journal of Metals, Materials and Minerals

Self-lubricating bearings are one of the oldest industrial applications of porous powder metallurgy parts, dating back to the mid-1920s. They remain the highest part produced by the P/M industry. The objective of this research was to study the effects of sintering time, sintering temperature and ratio of adding aluminium on sintered properties of Cu-10wt%Sn bearing that was produced from powder metallurgy processing. Various physical and mechanical properties such as density, percentage of porosity and hardness were tested to elucidate the effect of processing parameters. Phase identification and microstructure were analyzed by X-Ray Diffractometer and optical microscope, respectively. Sintering times in …

Thermal Models For A 3 Cm Miniature Xenon Ion Thruster, Coleman Thomas Younger

Master's Theses

In order to support UCLA’s development of the 3 cm Miniature Xenon Ion (MiXI) thruster, Cal Poly has a 3 cm thruster under development. This version, called MiXI Cal Poly Version 1 (MiXI-CPv1), is complete and has been utilized in vacuum chamber thermal validation testing. Testing on this version was used to check the validity of heat transfer simulations modeled in SolidWorks. Investigations of the 3 cm ion thruster configuration were intended to discover the driving factors affecting the thermal behavior of the discharge chamber and surrounding design space.

Numerical simulations indicate that the heating of the samarium cobalt permanent …

Cotextual Android Education, James R. Reed

Master's Theses

With advances in mobile phone hardware, the demand for mobile applica- tions has risen drastically. This has resulted in mobile phones becoming a pop- ular new medium for application development. However, the body of knowledge for contextual examples and tutorials leaves much to be desired. As of January 2010, California Polytechnic State University has offered a mobile development class that teaches students how to write applications for phones running Google’s Android platform. This class aims at taking advantage of students’ current in- terest in mobile applications to teach them about difficult computer science topics. As a corollary, the class hopes …

Modeling And Simulation Of Autonomous Thermal Soaring With Horizon Simulation Framework, Zhenhua Li

Master's Theses

A thermal is a column of warm rising air triggered by differential heating on the ground. In recent studies UAVs were programmed to exploit this free atmospheric energy from thermals to improve their range and endurance. Researchers had successfully flown UAVs autonomously with thermal soaring method. Most research involved some form of flight simulation. Improvements to the aircraft and thermal models for simulation purpose would enable researchers to better design their UAVs and explore any potential flaws in their designs. An aircraft simulation with a thermal environment was created in Horizon Simulation Framework, a modeling and verification framework that was …

Bemdec: An Adaptive And Robust Methodology For Digital Image Feature Extraction, Isaac Kueth Gang

Dissertations

The intriguing study of feature extraction, and edge detection in particular, has, as a result of the increased use of imagery, drawn even more attention not just from the field of computer science but also from a variety of scientific fields. However, various challenges surrounding the formulation of feature extraction operator, particularly of edges, which is capable of satisfying the necessary properties of low probability of error (i.e., failure of marking true edges), accuracy, and consistent response to a single edge, continue to persist. Moreover, it should be pointed out that most of the work in the area of feature …

Me-Em Enewsbrief, December 2010, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical and Aerospace Engineering eNewsBrief

No abstract provided.

New To Ols For Monitoring Gamma Camera Uniformity, Brad K. Lofton

Dissertations and Theses (Open Access)

Detector uniformity is a fundamental performance characteristic of all modern gamma camera systems, and ensuring a stable, uniform detector response is critical for maintaining clinical images that are free of artifact. For these reasons, the assessment of detector uniformity is one of the most common activities associated with a successful clinical quality assurance program in gamma camera imaging. The evaluation of this parameter, however, is often unclear because it is highly dependent upon acquisition conditions, reviewer expertise, and the application of somewhat arbitrary limits that do not characterize the spatial location of the non-uniformities. Furthermore, as the goal of any …

Hot Air Balloon Navigation, Dustin Blackwell

Aerospace Engineering

This report describes a program used for navigating a hot air balloon.  The program, Balloon_Trip, was written using MATLAB and gives a flight path to follow from a start position to an end position.  Balloon_Trip calculates the flight path by taking in wind conditions and then flying through these different winds so as to steer the hot air balloon.  The program calculates the flight path by taking into consideration at all times how the wind will propel the balloon while it is rising or falling in elevation.  It then takes the most direct and least complicated, if not fastest, …

Hydraulic Conductivity, Infiltration, And Runoff From No-Till And Tilled Cropland, Jessica H. Deck

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

Infiltration and runoff are important processes that affect the efficiency of center pivot irrigation systems. No-till planting systems potentially influence the hydraulic properties of soils and the soil surface conditions. The result of long-term use of no-till could be higher infiltration and lower runoff from rainfall and irrigation.

This potential was investigated in Nebraska on two center pivot irrigated sites; Fillmore County and Phelps County, one furrow irrigated site; South Central Agriculture Laboratory (SCAL), and one dryland site; Rogers Farm. Paired treatments were used at each location, one that was no-till planted and one that used two to three operations …

Polymer (Su-8) Optofluidic Device With Embedded Hydrogel Oxygen Sensing Elements, Zhan Gao, David B. Henthorn, Chang-Soo Kim

Chemical and Biochemical Engineering Faculty Research & Creative Works

The SU-8 photopolymer is an excellent alternative for traditional materials used in fluidic devices such as glass- or silicon-Based inorganic materials. We describe a new chemically anchored, lithographically patterned hydrogel sensing element embedded in a completed SU-8 fluidic channel structure after the channel bonding process. Polyethylene glycol (PEG) hydrogel films incorporating oxygen-responsive ruthenium-complex fluorophores are grafted and patterned by photopolymerization of solution-phase precursors on the modified SU-8 channel surface. the optofluidic sensing platform with this embedded sensing elements exhibited excellent performance in measuring dissolved oxygen content. a unique advantage of this method is the selective growth of various functional films …

Processing And Composition Effects On The Fracture Behavior Of Spray-Formed 7xxx Series Al Alloys, Mala M. Sharma, Constance W. Ziemian, Timothy J. Eden

Faculty Journal Articles

The fracture properties of high-strength spray-formed Al alloys were investigated, with consideration of the effects of elemental additions such as zinc,manganese, and chromium and the influence of the addition of SiC particulate. Fracture resistance values between 13.6 and 25.6 MPa (m)^1/2 were obtained for the monolithic alloys in the T6 and T7 conditions, respectively. The alloys with SiC particulate compared well and achieved fracture resistance values between 18.7 and 25.6 MPa (m)^1/2. The spray-formed materials exhibited a loss in fracture resistance (KI) compared to ingot metallurgy 7075 alloys but had an improved
performance compared to high-solute powder …

Identification Of Holocarboxylase Synthetase Chromatin Binding Sites In Human Mammary Cell Lines Using The Damid Technology, Dipika Singh

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

Holocarboxylase synthetase (HCS) is a chromatin protein that is essential for mediating the covalent binding of biotin to histones. Biotinylation of histones plays crucial roles in the repression of genes and repeats in the human genome. The objective of this project was to determine genomic binding sites of holocarboxylase synthetase (HCS) in the human chromatin of breast cell lines using an antibody independent technology. We tested the feasibility of DNA adenine methyltransferase identification (DamID) technology to map HCS binding sites in human mammary cell lines. Full-length HCS was fused to Dam for subsequent transfection into breast cancer (MCF-7) and normal …

The Effects Of Roof Solar Absorptance On Building Energy Performance In A Variety Of U.S. Climate Zones, Zachary Eubanks

Mechanical Engineering Undergraduate Honors Theses

The solar absorptance of a roof surface directly affects the solar heat gain through the roof. It has been shown that buildings in hot climates benefit from roofs with low absorptance. Cold and moderate climates have received less attention in previous studies. This paper simulates the effects on annual energy use, carbon dioxide emission, and utility cost of varying the solar absorptance of warehouse and small office building roofs in a wide variety of U.S. climate zones using EnergyPlus software and the DOE Commercial Building Benchmark Models. Results show that the optimum absorptance not only depends on the climate zone, …

Site Verification Of Weigh-In-Motion Traffic And Tirtl Classification Data, Shuo Li, Yingzi (Eliza) Du, Yi Jiang

JTRP Technical Reports

Quality weigh-in-motion (WIM) traffic data is essential not only in general transportation application, but also in pavement design. The new AASHTO Mechanistic-Empirical Pavement Design Guide (MEPDG) for New and Rehabilitated Pavement Structures requires information on the detailed truck traffic, such as truck traffic volume, truck traffic monthly and hourly variations, vehicle class distribution, axle load, and axle load distributions, instead of the traditional ESALs. In addition, the Indiana Department of Transportation (INDOT) needs to collect traffic data frequently so as to timely provide accurate traffic information for planning, program development, operations, and pavement management. Currently, INDOT is using the pneumatic …

Experimental And Computational Analysis Of An Energy Storage Composite Ankle Foot Orthosis, Michelle C. Hawkins

UNLV Theses, Dissertations, Professional Papers, and Capstones

Ankle Foot Orthotics (AFOs) are used by individuals presenting with Charcot-Marie-Tooth (CMT) to assist with improving gait. Mitch Warner, CPO, has developed a composite AFO made from woven carbon-Kevlar and carbon fiber lamina. The overall goals of the research are to characterize the HELIOS brace and to determine its effect on the gait of CMT subjects. Human motion analysis, experimental mechanical testing, and Finite Element Analysis (FEA) are used to gain a better understanding of how the materials and geometric design of the HELIOS AFO contribute to gait.

Human motion experiments are performed to determine the relationship between ground reaction …

Evaluation Of Video Based Pedestrian And Vehicle Detection Algorithms, Varun Bandarupalli

UNLV Theses, Dissertations, Professional Papers, and Capstones

Video based detection systems rely on the ability to detect moving objects in video streams. Video based detection systems have applications in many fields like, intelligent transportation, automated surveillance etc. There are many approaches adopted for video based detection. Evaluation and selecting a suitable approach for pedestrian and vehicle detection is a challenging task. While evaluating the object detection algorithms, many factors should be considered in order to cope with unconstrained environments, non stationary background, different object motion patterns and the variation in types of object being detected.

In this thesis, we implement and evaluate different video based detection algorithms …

Chemical And Electronic Structure Of Surfaces And Interfaces In Compound Semiconductors, Sujitra Pookpanratana

UNLV Theses, Dissertations, Professional Papers, and Capstones

The interface formation between two different materials is important in applications for optoelectronic devices. Often, the success or performance of these devices is dependent on the formation of these heterojunctions. In this work, the surface and interfaces in such materials for optoelectronic devices are investigated by a suite of X-ray analytical techniques including X-ray photoelectron (XPS), X-ray excited Auger electron (XAES), and X-ray emission (XES) spectroscopies to provide novel insight.

For the group III-nitrides (e.g., AlxGa1-xN) used in many light emitting devices, a significant challenge exists to form an Ohmic contact. The electron affinities and band gaps of GaN and …

Prediction Of Copper Grade At Flotation Column Concentrate Using Artificial Neural Network, F. Nakhaei, A. Sam, M. R. Mosavi, S. Zeidabadi

Mining Engineering Faculty Research & Creative Works

The flotation column is a multivariable process whose main control objective is to guarantee the metallurgical yield set for the process operation, expressed by the grade and the recovery of the valuable mineral in the concentrate. The on-line estimation of grade usually requires a significant amount of work in maintenance and calibration of on-stream analyzers, in order to maintain good accuracy and high availability. These difficulties and the high cost of investment and maintenance of these devices have encouraged the approach of prediction of metal grade as an index of control performance. Therefore, advanced new methods such as Artificial Neural …

Enhanced Mimo Lmmse Turbo Equalization, Jun Tao, Jingxian Wu, Yahong Rosa Zheng, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

We propose an enhanced linear minimum mean square error (LMMSE) turbo equalization scheme for multiple-input multiple-output (MIMO) communication systems. the turbo equalizer employs soft interference cancelation (SIC), where tentative soft decisions of the interfering symbols are subtracted from the received samples before the LMMSE filtering. the enhanced LMMSE turbo equalization with SIC introduces two improvements over existing methods. First, unlike existing methods that completely rely on the a priori soft decisions at the equalizer input for SIC, the new scheme performs SIC by continuously updating the soft decisions with the a posteriori information of the symbols that have just been …

Oversampled Ofdm Detector For Mimo Underwater Acoustic Communications, Jun Tao, Jingxian Wu, Yahong Rosa Zheng, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, an oversampled orthogonal frequency division multiplexing (OFDM) detector is proposed for multiple-input multiple-output (MIMO) underwater acoustic (UWA) communications. with simple time-domain oversampling and frequency-domain signal processing, the new oversampled OFDM (OOFDM) detector can achieve multipath diversity that is unavailable in a conventional uncoded OFDM system, while maintaining the similar complexity as the conventional OFDM system. the new OOFDM detector can be directly applied to the received OFDM signals without changing the structure of the OFDM transmitter. the proposed MIMO OOFDM detector has been tested by field trial data collected in the SPACE08 experiment launched near Martha's Vineyard, …

Modeling Connector Contact Condition Using A Contact Failure Model With Equivalent Inductance, Yu Ichi Hayashi, Songping Wu, Jun Fan, Takaaki Mizuki, Hideaki Sone

Electrical and Computer Engineering Faculty Research & Creative Works

It is found from previous studies on the immunity issues of CATV coaxial cables due to contact failure that, when contact resistance is small, the contact distribution and the number of contact points become factors that affect the degradation in immunity of the cables. However, when contact resistance is relatively large, the effects of the contact distribution and the number of contact points are negligible. in this paper, the physics of this phenomenon is further studied. Simulation results, validated by measurement, reveal that the contact distribution and the number of contact points contribute to parasitic inductances that could change the …

An Equivalent Three-Dipole Model For Ic Radiated Emissions Based On Tem Cell Measurements, Siming Pan, Jingook Kim, Sungnam Kim, Jaesu Park, Heoncheol Oh, Jun Fan

Electrical and Computer Engineering Faculty Research & Creative Works

An equivalent dipole model is proposed in this paper to represent the source of radiated electromagnetic emissions from an integrated circuit (IC). the height of an IC is usually much smaller than its length and width, so only three dipole moments are sufficient to characterize an IC in terms of its electromagnetic emissions. the dipole moments can be extracted from three TEM cell measurements. the radiated fields from the IC can then be calculated based on the extracted dipole sources. This IC emission model with three dipole moments is validated using the far-field measurements in a semi anechoic chamber for …