Engineering Commons^™

Propagation Of Ultrasound Through Freshly Excised Human Calvarium, Armando Garcia Noguera

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

The propagation of ultrasound through complex biological media, such as the human calvarium, poses a great challenge for modern medicine. Several ultrasonic techniques commonly used for treatment and diagnosis in most of the human body are still difficult to apply to the human brain, in part, because of the properties of the skull. Moreover, an understanding of the biomechanics of transcranial ultrasound may provide needed insight into the problem of blast wave induced traumatic brain injury (TBI). In the present study, the spatial variability of ultrasonic properties was evaluated for relevant frequencies of 0.5, 1, and 2.25 MHz. A total …

Acuta Enews July 2012 Vol. 41, No. 7

ACUTA Newsletters

In this issue....

1 What Matters to You

2 Overheard via eMail: Legacy Systems

3 UC Cloud Security: Avoiding an Identity Crisis

4 Board Report

4 Annual Dues Reminders Mailed July 3

5 Sense- Making: Why People Won't Be Replaced by Computers Anytime Soon

6 Young Professionals-- What's in It for You?

6 Webinar FREE to members

7 Info Links

8 PCI Compliance of Increasing Importance to Higher Ed

8 ACUTA Member Benefit: Post and Access RFPs

9 Welcome New Members

9 Check It Out

Development Of System Reliability Models For Railway Bridges, Anna Maria Rakoczy

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

Performance of the railway transportation network depends on the reliability of railway bridges, which can be affected by various forms of deterioration and extreme environmental conditions. More than half of the railway bridges in US were built before 1950 and many show signs of distress. There is a need for efficient methods to evaluate the safety reserve in the railway bridges by identification of the most sensitive parts of the bridge.

An accurate estimation of remaining fatigue life of a structural component is very important in prioritizing bridge rehabilitation and replacement. However, existing procedures to evaluate the fatigue behavior of …

The Role Of Rare Earth Dopants In Semiconducting Host System For Spin Electronic Devices, Juan A. Colon Santana

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

The doping of a wide band gap insulator offers an opportunity to increase the coupling between free carriers and magnetic impurities under the magnetic polaron model, leading to an enhanced in the Curie temperature of the host compound, critical for the fabrication of devices with magnetic properties. Some rare earth elements have large intrinsic magnetic moments due to unfilled 4d orbitals, and have been readily incorporated in materials for optical applications. Here the rare earths gadolinium and cerium were explored either as dopants or as part of the high-K semiconducting compound for the fabrication of magnetic heterojunction devices with magnetic …

Development And Recommendation For A Non-Proprietary, High-Tension, Cable End Terminal System, Ryan J. Terpsma, Ronald K. Faller, Dean L. Sicking, John D. Reid

Nebraska Department of Transportation: Research Reports

No abstract provided.

Test Matrices For Evaluating Cable Median Barriers Placed In V-Ditches, Ronald K. Faller, Scott K. Rosenbaugh, Mario Mongiardini, John D. Reid

Nebraska Department of Transportation: Research Reports

No abstract provided.

Life Cycle Boundaries And Greenhouse Gas Emissions From Beef Cattle, Quentin M. Dudley

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

Beef cattle are estimated to directly contribute 26% of U.S. agricultural greenhouse gas (GHG) emissions, and future climate change policy may target reducing these emissions. Life cycle assessment (LCA) of GHG emissions from U.S. feedlot beef cattle was conducted to compare methods of the U.S. Environmental Protection Agency (EPA) with a more complete evaluation of emissions. The inclusion of emissions from crop production for feed, associated land use change, and other minor factors nearly doubled GHG emissions associated with beef feedlots from the EPA Annual Inventory estimate of 1611 kgCO₂e hd^-1 yr^-1 to 3182 ± 167 …

Nonlinear Mechanical Behavior Of The Human Common, External And Internal Carotid Arteries In Vivo, Alexey Kamenskiy, Yuris A. Dzenis, Jason N. Mactaggart, Thomas G. Lynch, Syed A. Jaffar Kazmi, Iraklis I. Pipinos

Department of Mechanical and Materials Engineering: Faculty Publications

Introduction—The mechanical environment and properties of the carotid artery play an important role in the formation and progression of atherosclerosis in the carotid bifurcation. The purpose of this work was to measure and compare the range and variation of circumferential stress and tangent elastic moduli in the human common (CCA), external (ECA) and internal (ICA) carotid arteries over the cardiac cycle in vivo.

Methods—Measurements were performed in the surgically exposed proximal cervical CCA, distal ECA and distal ICA of normotensive patients (n = 16) undergoing carotid endarterectomy. All measurements were completed in vivo over the cardiac cycle …

Analysis Of Mechanically Milled Exchange Coupled Nanocomposite Permanent Magnets, Santanu Mukherjee

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

Nanocomposite permanent magnets have recently evoked wide interest because of their interesting properties. They usually consist of a hard magnetic phase having superior coercivities and a soft magnetic phase having improved values of magnetization and when they are coupled together, we get a permanent magnet with enhanced values of both the parameters and thus can be put to a lot of applications. Also to make this possible we can take advantage of the principle of exchange interaction which has been discussed subsequently in detail.

Also the microstructure plays a major role in obtaining good magnetic properties and the microstructure is …

Laser-Based Spectroscopy And Spectrometry, Xiangnan He

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

Laser-based spectroscopy and spectrometry were extensively investigated in nanoscience, materials science, biomedical science, and etc. Different lasers with wavelengths from ultraviolet to infrared, and with duration from continuous-wave (CW) to femtoseconds have been employed in various spectroscopic techniques to investigate the properties of materials and nanostructures. However, the sensitivity, spectral resolution, and spatial resolution of these techniques still need to be improved to better serve the purposes of detecting and analyzing various materials. The objective of the research in this dissertation is to improve the sensitivity, spectral resolution, and spatial resolution of different laser-based spectroscopy and spectrometry techniques, such as …

Distributed And Centralized Iterative Detection Of Self-Encoded Spread Spectrum In Multi-Channel Communication, Liang Chi, Won Mee Jang, Lim Nguyen

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

We propose self-encoded spread spectrum with two different iterative detection methods in multi-channel communication. The centralized iterative detection outperforms the iterative detection distributed over multiple channels. The results show that self-encoded spread spectrum with the centralized iterative detection is an excellent candidate for cognitive radio network.

Finite Element Analysis Of The Implantation Of A Self-Expanding Stent: Impact Of Lesion Calcification, Shijia Zhao, Linxia Gu, Stacey R. Froemming

Department of Mechanical and Materials Engineering: Faculty Publications

In this work, the deployment of a self-expanding stent in a stenosed artery was evaluated through finite element analysis. The three-layered structure of the artery and their material properties were measured and implemented in our computational models. The instant outcomes, including lumen gain, tissue prolapse, and stress distribution, were quantified, and the effect of plaque calcification was evaluated. Results showed that the peak wall stress occurred on the media layer regardless of plaque calcification. The calcified plaque mitigated the tissue prolapse and arterial wall stresses in general, compared with the soft plaque. However, the lesion calcification led to a more …

Acuta Enews June 2012 Vol. 41, No. 6

ACUTA Newsletters

In this issue...

1 Meeting Member Needs with Excellence

2 What's on Your Desk?

3 IPv6 Transition: The Time ls (Finally) Here

4 Board Report

5 Social Intelligence: Bringing the Human Touch to the Online Work place

5 Annual Dues Reminders Mail July 2

6 lnfo Links

7 Welcome New Members

7 Check lt Out

8-12 Annual Conference Photo Gallery

Research On Roadway Performance And Distress At Low Temperature, Yong-Rak Kim, Soohyok Im, Hoki Ban

Nebraska Department of Transportation: Research Reports

This research project investigated the performance and damage characteristics of Nebraska roadways at low-temperature conditions. To meet the research objective, laboratory tests were incorporated with mechanistic numerical modeling. The three most common pavement structures in Nebraska were selected and modeled considering local environmental conditions and pavement materials with and without truck loading. Cracking of asphalt overlay was predicted and analyzed by conducting finite element simulations incorporated with cohesive zone fracture. Parametric analyses were also conducted by varying pavement geometries and material properties, which could lead to helping pavement designers understand the mechanical sensitivity of design variables on the overall responses …

Safety Improvements At Highway-Railroad Crossing For Pedestrians And Bicyclists And The Assessment Of Long-Term Effects Of Centerline Curbing, Aemal Khattak, Zheng Luo

Nebraska Department of Transportation: Research Reports

No abstract provided.

Three-Dimensional Geometry Of The Human Carotid Artery, Alexey Kamenskiy, Jason N. Mactaggart, Iraklis I. Pipinos, Jai Bikhchandani, Yuris A. Dzenis

Department of Mechanical and Materials Engineering: Faculty Publications

Accurate characterization of carotid artery geometry is vital to our understanding of the pathogenesis of atherosclerosis. Three-dimensional computer reconstructions based on medical imaging are now ubiquitous; however, mean carotid artery geometry has not yet been comprehensively characterized. The goal of this work was to build and study such geometry based on data from 16 male patients with severe carotid artery disease. Results of computerized tomography angiography were used to analyze the cross-sectional images implementing a semiautomated segmentation algorithm. Extracted data were used to reconstruct the mean three-dimensional geometry and to determine average values and variability of bifurcation and planarity angles, …

Three-Dimensional Modeling Of Carbon/Epoxy To Titanium Single-Lap Joints With Variable Adhesive Recess Length, Yi Hua, Linxia Gu, Michael Trogdon

Department of Mechanical and Materials Engineering: Faculty Publications

The objective of this paper was to investigate the performance of recessed single-lap joints with dissimilar adherends through the finite element method. The influence of material and geometric nonlinearity of the adhesive as well as the impact of the recess length was examined in terms of maximum principal stresses. The strength of the joint was obtained as the load to initiate the crack propagation. Results suggested that either adding a spew fillet or considering the adhesive plasticity led to reduced peak stresses at the edge of the adhesive layer. The presence of a spew fillet in the single-lap joint with …

Co-Removal Of Atrazine And Nitrate From Groundwater Using A Mulch Biofilm, Allison L. Cole

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

The popular broadleaf herbicide atrazine is often found in contaminated groundwater along with other agricultural chemicals, such as nitrate. Mulch biowalls, a passive treatment placed in situ, can inexpensively remediate groundwater by intercepting and treating a contaminant plume. Three types of organic mulch: cedar, cypress, and hardwood were evaluated for their ability to act as supporting materials for a biowall to simultaneously remove atrazine and nitrate from groundwater. Physical and chemical properties of the mulch were characterized. Cedar mulch had the highest organic carbon content, 996 mg/g. The adsorptive capacity of the mulch for atrazine and nitrate, in mono …

Development And Validation Of A Model For Granular Material Volume Measurements, Pourya Fasounaki

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

Keeping inventory record of packed grains in silos poses challenges since the bulk material’s different segments do not discharge uniformly, leading to formation of random peaks and valleys on the surface. To facilitate obtaining accurate volume measurement of the grains by taking into account this non-linear behavior on the surface, laser or plumb-bob level-sensing devices are employed at different part of the surface to probe the level of material under those regions.

The main goals of this research is to study the behavior of granular material in silo while discharging downward and by doing so, differentiate certain flow patterns formed …

Identification Of A Maximum Guardrail Height For The Midwest Guardrail System Using Computer Simulation, Ramen D. Julin

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

W-beam guardrails are by far the most common restraint system used along both local and major roadways. Traditionally, these restraint systems have been full-scale crash tested with a rail height ranging between 27 in. and 32 in. However, the maximum rail height which allows for safe performance of guardrails, especially in impacts involving small vehicles, has never been identified.

The main concern associated with an increase of the rail height is that small vehicles, because of their low profile, may have a tendency to lift the rail and penetrate the barrier. The objective of this project was to determine the …

A Scalable Inline Cluster Deduplication Framework For Big Data Protection, Yinjin Fu, Hong Jiang, Nong Xiao

School of Computing: Technical Reports

Cluster deduplication has become a widely deployed technology in data protection services for Big Data to satisfy the requirements of service level agreement (SLA). However, it remains a great challenge for cluster deduplica- tion to strike a sensible tradeoff between the conflicting goals of scalable dedu- plication throughput and high duplicate elimination ratio in cluster systems with low-end individual secondary storage nodes. We propose Σ-Dedupe, a scalable inline cluster deduplication framework, as a middleware deployable in cloud da- ta centers, to meet this challenge by exploiting data similarity and locality to op- timize cluster deduplication in inter-node and intra-node scenarios, …

Remote Chemical And Elemental Analyss By Ultra Fast Spectroscopy, Dennis R. Alexander

Department of Electrical and Computer Engineering: Faculty Publications

Systems and methods are provided for monitoring materials using ultra fast laser pulses. Ultra fast laser pulses, such as femtosecond or attosecond laser pulses, are applied to the materials and laser pulses that result from interactions between the ultra fast laser pulses and the materials are collected. Spectral content of the resulting pulses is generated and presented. The elemental composition of the materials is determined using the spectral content.

Rehabilitation And Exercise Machine, Judith M. Burnfield, Yu Shu, 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.

An Energy Cost Optimization Method For A Large-Scale Hybrid Central Cooling Plant With Multiple Energy Sources Under A Complex Electricity Cost Structure, Yin Guo

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

The cooling energy cost could be a significant portion of the total energy cost for a large organization or building complex during summer. A hybrid system or thermal energy storage system is usually applied to reduce the energy cost. However, without proper integration and operation, the advantage of using such systems could be limited.

This study presents a general energy cost optimization methodology and mathematical model for a hybrid cooling system under a complex electricity cost structure. The model considers the efficiency of the hybrid cooling system and multiple energy sources. The energy cost evaluation reflects a complex cost structure …

An Enhanced Self-Adaptive Mapreduce Scheduling Algorithm, Xiaoyu Sun

School of Computing: Dissertations, Theses, and Student Research

MapReduce is a framework for processing huge amounts of data in a distributed environment and Hadoop is Apache’s open source implementation of MapReduce, which is widely used. However, Hadoop’s performance is currently limited by its default task scheduler, which assumes that cluster nodes are homogeneous when estimating the task progress and choosing slow tasks for re-execution. In practice, the homogeneity assumption does not always hold. Longest Approximate Time to End (LATE) is a scheduling algorithm that takes heterogeneity into account. It, however, still depends on a static method to estimate the task execution time. As a result, neither Hadoop default …

Prestressed Concrete Wind Turbine Supporting System, Ibrahim Lotfy

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

Wind energy is one of the most commercially developed and quickly evolving renewable energy technologies worldwide. Wind turbines are commonly supported on tubular steel towers. As the turbines are growing and the towers are elevating, an increase in structural strength and stiffness is required to withstand the applied forces. Recent studies established concrete as a more economic and durable alternative to steel especially when the tower height exceed 240ft. Presently, concrete towers are not common due to their perceived heavy weight and assembly complexity. One of the systems that have been mentioned in the literature consists of precast rings that …

Study Of Grinding Burn Using Design Of Experiments Approach And Advanced Kaizen Methodology, Kiruthika Devi Sundarrajan

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

Grinding burn has been one of the re-occurring issues at a leading automotive manufacturer. Historically when grinding burn occurred, trial and error was used to delicately find a set up process settings that provided good-enough-to-get-by results, but not optimal. Some changes include changing the coolant manifold to improve the coolant flow and rate, changing the grinding wheel, changing the type of coolant. The experiments have proved to introduce some improvements, however the occurrence of grinding burns have not been reduced or quantified and the cause of the grinding burn has not been identified or quantified. Grinding is a complex phenomenon …

A Multi-Modal Sensing And Communication Platform For Continental-Scale Migratory Bird Tracking, David J. Anthony

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

This thesis presents a novel platform for tracking migratory birds on a continental scale. Cellular technology is used to augment the short-range radios that have traditionally been used in wireless sensor networks. The platform utilizes multiple sensors, including a GPS and solid state compass. By using these sensors, the platform is capable of not only tracking a bird’s migration path, but also provides information on a bird’s behavior during its life-cycle. Testing methodology utilizing simulations and aspect-oriented programming is used to reveal faults in the platform prior to deployment on wild animals. In collaboration with the International Crane Foundation, and …

Technological Aspects Of Molecular Diagnosis Of Bacterial Infectious Diseases, Christine S. Booth

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

The polymerase chain reaction (PCR) is continually growing in its application, particularly in the field of molecular diagnosis of disease from clinical specimens. The main focus has been in the detection and identification of pathogens. However, quantitative PCR is increasingly utilized to determine initial pathogen load. A well-designed PCR protocol is required in all of these instances. Just as importantly, in the context of disease diagnosis; is the design of the sample processing methodology. The ideal method should concentrate the DNA and effectively isolate a high-quality DNA product, free of PCR inhibitors, while also being simple, reproducible and safe.

The …

Acuta Enews May 2012 Vol. 41, No. 5

ACUTA Newsletters

In this issue...

1 Looking Back at 2011'2012

2 NSF Funding for Cyber-learning: Transforming Education

3 Choose Your VoIP Host Carefully

3 ACUTA Webinar: Creating a Project Management Office

4 7 Must-Haves in a UC Cloud Contract

5 Board Report

6 How Cross-Cultural Competency Will Build Workers' Global Agility

6 Annual Dues Invoices Mail May 1

7 Info Links

8 Welcome New Members

8 Check It Out