Engineering Commons^™

Extrusion And Alkali Extrusion Of Corn Stover To Improve Enzyme Saccharification, Shujing Zhang

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

Biomass pretreatment constitutes an important part in the whole process of bioethanol production. The main goals of pretreatment include improving cellulose accessibility to enzyme, enhancing sugar yields from hemicellulose, achieving low capital and energy costs, as well as low sugar degradation and low chemical requirements. Extrusion, as a continuous and high throughput pretreatment method, requires much less chemical compared to traditional alkali pretreatment. In this research, twin-screw extrusion was evaluated for its effect with regard to promoting sugar yields from corn stover. Also, the underlying factors contributing to this improvement were examined. It was found that extrusion with no chemicals …

Effects Of Mass Layer Dimension On A Finite Quartz Crystal Microbalance, Y. P. Kong, Jinxi Liu, Huijing He, Jiashi Yang

Department of Mechanical and Materials Engineering: Faculty Publications

In this paper, we investigate free thickness-shear and thickness-twist vibrations of a finite crystal resonator of AT-cut quartz carrying a thin mass layer at the central portion of its top surface operating as a quartz crystal microbalance. 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 vibration confinement by the mass layer are calculated and examined.

Testing Fuel Efficiency Of Tractors With Both Continuously Variable And Standard Geared Transmissions, Christopher N. Howard, Michael F. Kocher, Roger M. Hoy, Erin E. Blankenship

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

A John Deere 8295R IVT tractor with a continuously variable transmission (CVT) and a John Deere 8295R PowerShift (PST) tractor (Waterloo, Iowa) with a standard geared transmission (GT) were tested for fuel consumption at three different travel speeds with six different load levels applied per speed. The JD 8295R PST tractor was tested both at full throttle (FT) and shifted up two gears and throttled back (SUTB) to achieve the same travel speed as at full throttle conditions. For each travel speed with each transmission mode, fuel consumption was determined to be linearly related to drawbar power. Linear regression results …

Streambank Erosion And Instability Induced By Groundwater Seepage, Taber L. Midgley, Garey A. Fox, Glenn V. Wilson, Derek M. Heeren, Andrew Simon, Eddy J. Langendoen

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Excessive sediment is one of the most common surface water pollutants. It diminishes water quality and destroys aquatic habitat. Streambank erosion is known to be a major source of sediment in streams and rivers, contributing as much as 80% of the total sediment load in some watersheds. Little work has been done to study the effects of seepage on streambank erosion and failure. Prior research, primarily in the laboratory under well-defined and controlled conditions, has examined seepage as a mechanism for bank erosion, but more needs to be done to validate conclusions derived from the laboratory with field data. This …

Domain Size And Structure In Exchange Coupled [Co/Pt]/Nio/[Co/Pt] Multilayers, Andrew G. Baruth, Shireen Adenwalla

Shireen Adenwalla Papers

We investigate the competing effects of interlayer exchange coupling and magnetostatic coupling in the magnetic heterostructure ([Co/Pt]/NiO/[Co/Pt]) with perpendicular magnetic anisotropy (PMA). This particular heterostructure is unique among coupled materials with PMA in directly exhibiting both ferromagnetic and antiferromagnetic coupling, oscillating between the two as a function of spacer layer thickness. By systematically tuning the coupling interactions via a wedge-shaped NiO spacer layer, we explore the energetics that dictate magnetic domain formation using high resolution magnetic force microscopy coupled with the magneto-optical Kerr effect. This technique probes the microscopic and macroscopic magnetic behavior as a continuous function of thickness and …

Cooperative Wireless Communications: The Impact Of Channel Uncertainty And Physical-Layer Security Considerations, Junwei Zhang

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

In this thesis, cooperative wireless communication strategies are studied in the presence of channel uncertainty and physical-layer security considerations. Initially, achievable rates and resource allocation strategies for imperfectly-known fading relay channels are investigated. Amplify-and-forward (AF) and decode-and-forward (DF) relaying schemes with different degrees of cooperation are considered. The corresponding achievable rate expressions are obtained and efficient resource allocation strategies are identified. Then, the analysis is extended to two-way decode-and-forward (DF) fading relay channels. In the second part of the thesis, the concentration is on wireless information-theoretic security. First, collaborative beamforming schemes for both DF and AF relaying are studied under …

Cyclostationary Detection For Ofdm In Cognitive Radio Systems, Marcos E. Castro

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

Research on cognitive radio systems has attracted much interest in the last 10 years. Cognitive radio is born as a paradigm and since then the idea has seen contribution from technical disciplines under different conceptual layers. Since then improvements on processing capabilities have supported the current achievements and even made possible to move some of them from the research arena to markets.

Cognitive radio implies a revolution that is even asking for changes in current business models, changes at the infrastructure levels, changes in legislation and requiring state of the art technology.

Spectrum sensing is maybe the most important part …

Expression And Characterization Of Protein Chimera With Embedded Activated Protein C Generation, Minjeong Schneider

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

Increasing demand of medical implants has lead researchers to develop biomaterial surfaces that offer improved performance and lower thrombogenecity. There have been attempts to model biomaterial surfaces after the native endothelium as it represents an optimal non-thrombotic surface. Typically, when biomaterials are contacted with blood, they often invoke the activation of clotting cascades. Thus, to overcome surface mediated thrombotic events, proteins and molecules with anticoagulant attributes of the endothelium have been immobilized onto biomaterial surfaces. Protein C (PC) plays a main role in blood coagulation and acts as an anticoagulant when it is converted into activated protein C (APC). Activation …

Performance Rating Of De-Icing Chemicals For Winter Operations, Barbara M. Gerbino-Bevins

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

The cost of deicing chemicals is a significant part of the Nebraska Department of Road's winter maintenance budget. Many products are available for use in highway and bridge deicing and new products are introduced each year. The objectives of this research are to develop a laboratory test to evaluate the performance of chemical deicers, to investigate national, state, and local standards, and to develop best maintenance practices to optimize the use of chemical deicers.

This research project consists of two phases:

Phase 1: conduct a literature survey to find data from existing laboratory tests used to evaluate deicer performance.

Phase …

Application Of Shredded-Tire Biofilter And Membrane Bioreactor For Greywater Reclamation, Meng Hu

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

Water scarcity is a pressing global issue. Greywater (GW) reclamation is a viable option to reduce freshwater demand. The objectives of this work were to: a) evaluate the feasibility of the combination of shredded tire biofilter (STB) technology and membrane bioreactor (MBR) technology in GW reclamation; b) study the effects of various parameters on STB performance; and c) understand the fouling mechanisms to lower the energy consumption in MBRs. Bench-scale STBs and MBRs (flat-sheet membranes) were constructed to address the first two objectives, while an independent membrane (hollow-fiber membranes) fouling experiment was designed for the third objective.

It was found …

Six Degree Of Freedom Miniature In Vivo Robot For Laparoendoscopic Single-Site Surgery, Ryan L. Mccormick

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

The shift in surgery from open procedures to minimally invasive surgery (MIS) techniques have provided benefits of decreased recovery time, improved cosmetic results, and reduced costs. As advances in MIS move to minimize the number of external incisions, such as with Laparoendoscopic Single-Site (LESS) surgery, additional complexities are introduced. These complexities, including unintuitive controls, reduced dexterity, and limited workspace, hinder these methods from more widespread implementation in more complicated surgical procedures.

Through the use of a miniature in vivo robotic surgical platform designed for LESS surgery, these complexities can be mitigated, allowing for wider adoption of MIS by placing the …

Influence Of Process Parameters On Health Outcome, Vijaya K. Musunuru

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

In the recent years, healthcare organizations have realized that quality in providing service is critical for their survival in this competitive world. This increased attention to service quality has forced many health care providers to reevaluate their systems to stay in business. The main purpose of this study is to test the hypothesis “Process Quality predicts the Product quality (patient satisfaction) in the healthcare domain”. The objective of this study was three- fold. The first objective is to analyze historical data both on patient satisfaction and on provider attributes to yield process parameters for a particular area in a hospital. …

Simulation And Control System Of A Railroad Track Power Harvesting Device, Kyle J. Phillips

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

With the vastness of existing railroad infrastructure, there exist numerous road crossings which are lacking warning light systems and/or crossing gates due to their remoteness from existing electrical infrastructure. Along with lacking warning light systems, these areas also tend to lack distributed sensor networks used for railroad track health monitoring applications. With the power consumption required by these systems being minimal, extending electrical infrastructure into these areas would not be an economical use of resources. This motivated the development of an energy harvesting solution for remote railroad deployment.

This thesis describes a computer simulation created to validate experimental on-track results …

Energy Harvesting Systems Design For Railroad Safety, Abolfazl Pourghodrat

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

Railroad grade crossings are locations of significant interest for prevention of collisions, injuries and fatalities. Another area of concern is derailments resulting from mechanically deficient track structures. Many of these incidents occur in remote areas due to the lack of electrical infrastructure to power automated warning systems and/or track health monitoring sensor networks.

Providing electrical infrastructure to railroad crossings in remote areas is often not economical, and other alternative sources of electricity such as solar and wind energy are not reliable or robust. This motivated development of devices for in situ energy harvesting.

Initially, an improved mechanical energy harvesting device …

Robotic Manipulator With Multiple Instruments For Natural Orifice Translumenal Endoscopic Surgery, Chi Min Seow

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

This thesis presents a novel robotic manipulator with multiple instruments for use in Natural Orifice Translumenal Endoscopic Surgery (NOTES). NOTES is a newly emerging surgical technique that eliminates external incisions on patients’ skin. As a result, better cosmetics, shorter recovery time, and reduced risk of external infection can be achieved.

Research has been ongoing in academia and industry to make this surgical procedure more feasible in human surgeries. Although several robotic platforms have been developed, none of them has the required capability to provide surgeons with the most appropriate tool in a safe and timely matter during surgery. This robotic …

Investigation Of Rfid Readability For License Plates In Static And Motion Testing, Srinivasan Venkatesan

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

The most important function of RFID in vehicle tracking is to store information concerning tagged elements in order to improve the overall performance of movable asset management. There is a need to discover an RFID system for the tracking of vehicles, as existing vehicle tracking systems are undependable. Experiments were performed with SIRIT, SAVI, and RF code RFID systems under differing conditions, attaching the tag to the license plate instead of the windshield. Different spacers were also tested to reduce the effect of metal surfaces on RFID signals.

Preliminary experiments were performed before stationary and motion testing in order to …

Quantitative Analysis Of The Reaction Between Gliadin And Citric Acid Under Weak Acidic And Weak Alkaline Conditions, Wei Li

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

Gliadin was reacted with citric acid under weak acidic and weak alkaline conditions in both wet and dry states and the reaction mechanism was studied. The low morphological stability in an aqueous environment and inferior mechanical properties have restricted the applications of plant proteins, although these materials possess a unique structure, biocompatibility and biodegradability. Carboxylic acids such as citric acid are inexpensive and nontoxic chemicals and are preferred for crosslinking proteins and cellulose to improve the desired properties of the materials.

In this study, gliadin was chosen as a model of plant proteins to react with citric acid. However, previous …

Wireless Embedded Smart Cameras: Performance Analysis And Their Application To Fall Detection For Eldercare., Alvaro Pinto

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

Wireless Embedded Smart Camera Networks has received a lot of attention from academia and industry because they are small in size and easy to deploy, and they offer a multitude of attractive applications. They can be used for embedded single unit applications, or can be networked for multi-camera applications.

We first analyze three different operation scenarios for a wireless vision sensor network wherein different levels of local processing is performed. A detailed quantitative comparison of three operation scenarios are presented in terms of energy consumption and latency. This quantitative analysis provides the motivation for performing high-level local processing and decision …

Fracture Analyses Of Aging Aircraft Structures And Human Aorta, Ananth Ram Mahanth Kasavajhala

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

Understanding the behavior of fracture due to preliminary flaws in materials is essential to escalate the life and reliability of a structure. The present work is focused on investigating the influence of various structural parameters on the pre-crack growth stress state, initiation and propagation of flaws in two distinct fields of engineering that is, aging aircraft structural repair (aerospace) and the human aortic dissection (life sciences). Three dimensional finite element methodologies, coupled with linear elastic fracture mechanics (LEFM) formulation was utilized in both the cases.

A model of pre-cracked Al 7075 T6 plate was used to analyze pre- and post- …

Applied And Mechanistic Studies Of Microbial 17beta-Estradiol Degradation, Zhongtian Li

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

The presence of natural estrogens, a class of endocrine disrupting compounds, in water has caused increasing concerns over their adverse impacts on the health of aquatic eco-systems and human beings. In this study, adsorption characteristics of two natural estrogens, 17β-estradiol (E2) and estrone (E1), on granular activated carbon (GAC) were investigated in isotherm tests and in a GAC column. The GAC column was then converted to a biologically active carbon (BAC) column and the removal efficiency of E2 and its primary biodegradation intermediate E1 were monitored. During BAC operation, the impacts of various reactor operation parameters, such as the carbon …

Roadside Grading Guidance, Kevin D. Schrum

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

Provisions for the design of roadside foreslopes are not readily available, and as a result, engineering judgment is often employed. Unfortunately, this can lead to inconsistent designs, where, inevitably, some designs will be too costly and other designs will be too dangerous. Therefore, a design guide was created to lend consistency to the design of these foreslopes while maintaining the most economical and safe design.

This design guide was prepared after conducting a benefit-cost analysis using the Roadside Safety Analysis Program (RSAP). A large test matrix was developed in an attempt to simulate the most possible scenarios, leaving interpolation to …

Molecular Dynamics Simulation Based On Hadoop Mapreduce, Chen He

School of Computing: Dissertations, Theses, and Student Research

Molecular Dynamics (MD) simulation is a computationally intensive application used in multiple fields. It can exploit a distributed environment due to inherent computational parallelism. However, most of the existing implementations focus on performance enhancement. They may not provide fault-tolerance for every time-step.

MapReduce is a framework first proposed by Google for processing huge amounts of data in a distributed environment. The simplicity of the programming model and fault- tolerance for node failure during run-time make it very popular not only for commercial applications but also in scientific computing.

In this thesis, we develop a novel communication-free and each time-step fault- …

Real-Time Divisible Load Scheduling For Cluster Computing, Anwar Mamat

School of Computing: Dissertations, Theses, and Student Research

Cluster computing has become an important paradigm for solving large-scale problems. However, as the size of a cluster increases, so does the complexity of resource management and maintenance. Therefore, automated performance control and re- source management are expected to play critical roles in sustaining the evolution of cluster computing. The current cluster scheduling practice is similar in sophistication to early supercomputer batch scheduling algorithms, and no consideration is given to desired quality-of-service (QoS) attributes. To fully avail the power of computational clusters, new scheduling algorithms that provides high performance, QoS assurance, fault-tolerance, energy savings and streamlined management of the cluster …

Integration Of A Real Option Of An Environmental Project, Qi Yang

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

This thesis explores a problem of how to evaluate environmental projects under the Carbon Cap-and-Trade Scheme (CCTS) from the perspective of an individual firm. The focus is the integration of a real option approach for project investment timing and financial carbon option approach for carbon credit management. The real option is for a mid or long term decision on when to invest on the environmental project, and the financial option is for a supplementary decision to hedge short-term residue risks. Two uncertainties (the carbon price and carbon credit demand) are considered, and their changes are represented by a lattice of …

Zein Nanospheres For Gene Delivery, Mary C. Regier

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

Particulates incorporating DNA provide for protection and sustained release of DNA, and thus are promising candidates for DNA delivery systems. Among the routes of administration for gene delivery, the oral route is perhaps the most appealing as it is associated with patient comfort and compliance and allows for targeting to intestinal targets for therapeutic and vaccination applications. With the goal of realizing the potential of an oral DNA delivery system, zein, a hydrophobic protein from corn that is biocompatible and degraded enzymatically, was investigated. This thesis describes the formulation of zein nanospheres encapsulating DNA by a coacervation technique and their …

Theoretical And Numerical Research On Sediment Transport In Pressurized Flow Conditions, Zhaoding Xie

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

Research of river bed erosion is an important part of designing bridges and transportation networks since the stability and hydrodynamic response of bridges critically depends on river bed scour. The engineering designers traditionally focus on the local scour around hydraulic structures, such as piers and abutments, in open channel flow. The pressurized scour under a submerged bridge deck is seldom researched.

In this study, the commercial CFD codes, FLOW3D and STARCCM+, are adopted to simulate pressure scour under a bridge deck with six girders. Several limitations for FLOW3D are found during its application of sediment transport model: a) the scour …

Enhancement Of Optical Emission From Laser-Induced Plasmas By Combined Spatial And Magnetic Confinement, L. B. Guo, W. Hu, B. Y. Zhang, X. N. He, C. M. Li, Y. S. Zhou, Z. X. Cai, X. Y. Zeng, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

Within the past decades, laser-induced breakdown spectroscopy (LIBS) has become a well-established and powerful optical emission spectroscopy (OES) analytical technique [1–5]. As a useful analytical tool, LIBS is used extensively in various areas such as remote detection, hostile environment monitoring, and cultural heritage conservation [6–10]. Researchers are paying more attention to LIBS as a diagnostic method for elemental analysis as it is characterized by fast, real-time, in situ, low invasiveness, and multi-elemental diagnosis, normally without the need for sample preparation [11,12]. However, one of its major drawbacks is its low sensitivity, which seriously hinders further improving the limit of detection …

Vertical Track Modulus Trending, Shane Michael Farritor, Sheng Lu

Department of Mechanical and Materials Engineering: Faculty Publications

Systems and methods for determining a trend in Vertical track modulus are disclosed in accordance with embodiments of the present invention. Vertical deflection data is collected along a particular section of railroad track. A first set of Vertical track modulus is determined, based in part, on the collected vertical deflection data. At a second time, vertical deflection data is again collected along the particular section of railroad track to be used in determining a second set of vertical track modulus. At least the first and second sets of Vertical track modulus are analyzed to determine a math ematical algorithm that …

Apparatus For Dispensing Material, Peter Werner Sutter, Eli Anguelova Sutter

Department of Electrical and Computer Engineering: Faculty Publications

An apparatus capable of dispensing drops of material with volumes on the order of Zeptoliters is described. In some embodiments of the inventive pipette the size of the droplets so dispensed is determined by the size of a hole, or channel, through a carbon shell encapsulating a reservoir that contains material to be dispensed. The channel may be formed by irradiation with an electronbeam or other high-energy beam capable of focusing to a spot size less than about 5 nanom eters. In some embodiments, the dispensed droplet remains attached to the pipette by a small thread of material, an atomic …

Acuta Enews July 2011, Vol 40, No. 7

ACUTA Newsletters

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From the President: The "T" in ACUTA....... Joe Harrington, Boston College

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The Daily Grind: What's on Your Desk Today?.......... Mona Brennan-Cotes, Univ. of Western Ontario

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"The Future of Voice Communications": Winter Journal Looking for Articles

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