Engineering Commons^™

Creep In Photovoltaic Modules: Examining The Stability Of Polymeric Materials And Components, David C. Miller, Michael D. Kempe, Stephen H. Glick, Sarah R. Kurtz

Publications (E)

Interest in renewable energy has motivated the implementation of new polymeric materials in photovoltaic modules. Some of these are non-cross-linked thermoplastics, in which there is a potential for new behaviors to occur, including phase transformation and visco-elastic flow. Differential scanning calorimetry and rheometry data were obtained and then combined with existing site-specific time-temperature information in a theoretical analysis to estimate the displacement expected to occur during module service life. The analysis identified that, depending on the installation location, module configuration and/or mounting configuration, some of the thermoplastics are expected to undergo unacceptable physical displacement. While the examples here focus on …

"Buried-Anode" Technology Leads To Advanced Lithium Batteries, National Renewable Energy Laboratory

Publications (E)

A technology developed at the National Renewable Energy Laboratory has sparked a start-up company that has attracted funding from the Advanced Projects Research Agency-Energy (ARPA-E). Planar Energy, Inc. has licensed NREL's "buried-anode" technology and put it to work in solid-state lithium batteries. The company claims its large-format batteries can achieve triple the performance of today's lithium-ion batteries at half the cost, and if so, they could provide a significant boost to the emerging market for electric and plug-in hybrid vehicles.

An Exploratory Model For Predicting Post-Consumer Recycled Pet Content In Pet Sheets, Dong Ho Kang, Rafael Auras, Keith Vorst, Jay Singh

Industrial Technology and Packaging

An exploratory model for determining post-consumer recycled polyethylene terephthalate (PET) content in PET sheets for one specific stream of mechanically recycled PET (RPET) was developed. Six kinds of PET sheets with varying percent of virgin (V) and recycled (R) PET contents (i.e., 100V, 80V20R, 60V40R, 40V60R, 20V80R, and 100R PET) were commercially extruded. The optical, thermal, physicomechanical and barrier properties of the PET sheets were evaluated as function of RPET content. Differences were found between the sheets for UV and visible light absorption in the regions 200–350 nm and 670–700 nm, respectively. Intrinsic viscosities of 100V and 100R PET sheets …

Validation Of Proposed Metrics For Two-Body Abrasion Scratch Test Analysis Standards, Ryan L. Kobrick, David M. Klaus, Kenneth W. Street

Publications

The objective of this work was to evaluate a set of standardized metrics proposed for characterizing a surface that has been scratched from a two-body abrasion test. This is achieved by defining a new abrasion region termed “Zone of Interaction” (ZOI). The ZOI describes the full surface profile of all peaks and valleys, rather than just measuring a scratch width as currently defined by the ASTM G 171 Standard. The ZOI has been found to be at least twice the size of a standard width measurement, in some cases considerably greater, indicating that at least half of the disturbed surface …

Markov Models For Biogeography-Based Optimization, Daniel J. Simon, Mehmet Ergezer, Dawei Du, Rick Rarick

Electrical and Computer Engineering Faculty Publications

Biogeography-based optimization (BBO) is a population-based evolutionary algorithm that is based on the mathematics of biogeography. Biogeography is the science and study of the geographical distribution of biological organisms. In BBO, problem solutions are analogous to islands, and the sharing of features between solutions is analogous to the migration of species. This paper derives Markov models for BBO with selection, migration, and mutation operators. Our models give the theoretically exact limiting probabilities for each possible population distribution for a given problem. We provide simulation results to confirm the Markov models.

Dynamic Companion Harmonic Circuit Models For Analysis Of Power Systems With Embedded Power Electronics Devices, H. Garcia, M. Madrigal, B. Vyakaranam, R. Rarick, F. Eugenio Villaseca

Electrical and Computer Engineering Faculty Publications

In this paper a methodology that extends the dynamic harmonic domain (DHD) analysis of large networks is presented. The method combines DHD analysis and discrete companion circuit modeling resulting in a powerful analytic technique called dynamic companion harmonic circuit modeling. It provides for a complete dynamic harmonic analysis of the system while preserving the advantages of discrete companion circuit models. The methodology is illustrated by its application to a three-node power system, where reactive power compensation is achieved using a fixed-capacitor, thyristor-controlled reactor (FC-TCR) and its control system.

Electroporation-Induced Electrosensitization, Olga N. Pakhomova, Betsy W. Gregory, Vera A. Khorokhorina, Anglela M. Bowman, Shu Xiao, Andrei G. Pakhomov

Bioelectrics Publications

BACKGROUND: Electroporation is a method of disrupting the integrity of cell membrane by electric pulses (EPs). Electrical modeling is widely employed to explain and study electroporation, but even most advanced models show limited predictive power. No studies have accounted for the biological consequences of electroporation as a factor that alters the cell's susceptibility to forthcoming EPs.

METHODOLOGY/PRINCIPAL FINDINGS: We focused first on the role of EP rate for membrane permeabilization and lethal effects in mammalian cells. The rate was varied from 0.001 to 2,000 Hz while keeping other parameters constant (2 to 3,750 pulses of 60-ns to 9-micros duration, 1.8 …

Laser Etched Pmma Microfluidic Chip Design And Manufacture With Applications In Capillary Zone Electrophoresis, Evan Allen Barbre

Master's Theses

This thesis encompasses a feasibility study of using low-cost materials to manufacture microfluidic chips that can perform the same functions as chips manufactured using traditional methods within an acceptable range of efficiency of chips created with more exotic methods and materials. The major parts of the project are the selection and characterization of the fabrication methods for creating the channels for fluid flow, the methods for sealing the channels to create a usable chip and the electrophoretic separations of carboxylated microspheres of different potentials. In this work we seek to answer the question if laser-etched PMMA microfluidic chips are comparable …

A Microsimulation Of Traffic, Parking, And Emissions At California Polytechnic State University – San Luis Obispo, Steven Michael Kilbert

Master's Theses

Traffic and parking congestion are significant issues at many universities nationwide. The delays experienced result in wasted time, money, and fuel for students, faculty and staff, not to mention the negative contributions to the environment. This paper quantifies the amount of vehicle emissions generated during an average morning peak hour in the university environment. Using VISSIM and CMEM microsimulation packages, a model is created for California Polytechnic State University- San Luis Obispo to aggregate the collective transportation behaviors and practices of the campus and recognize the implications these behaviors pose on the transportation network as a whole. Reasonable estimates are …

Sar Map Of Gel Phantom In A 64mhz Mri Birdcage By Fiber-Optic Thermometry And Fdtd Simulation, Chirag Mukesh Patel

Master's Theses

As implantable medical devices are being used more often to treat medical problems for which pharmaceuticals don’t suffice, it is important to understand their interactions with commonly used medical modalities. The interactions between medical implants and Magnetic Resonance Imaging machines have proven to be a risk for patients with implants.

Implanted medical devices with elongated metallic components can create harmful levels of local heating in a Magnetic Resonance Imaging (MRI) environment [1]. The heating of a biological medium under MRI is monitored via the Specific Absorption Rate (SAR). SAR, defined as power absorbed per unit mass (W/kg), can be calculated …

Time–Frequency Cepstral Features And Heteroscedastic Linear Discriminant Analysis For Language Recognition, Wei-Qiang Zhang, Liang He, Yan Deng, Jia Liu, Michael T. Johnson

Electrical and Computer Engineering Faculty Research and Publications

The shifted delta cepstrum (SDC) is a widely used feature extraction for language recognition (LRE). With a high context width due to incorporation of multiple frames, SDC outperforms traditional delta and acceleration feature vectors. However, it also introduces correlation into the concatenated feature vector, which increases redundancy and may degrade the performance of backend classifiers. In this paper, we first propose a time-frequency cepstral (TFC) feature vector, which is obtained by performing a temporal discrete cosine transform (DCT) on the cepstrum matrix and selecting the transformed elements in a zigzag scan order. Beyond this, we increase discriminability through a heteroscedastic …

Versatile Spectral Imaging With An Algorithm-Based Spectrometer Using Highly Tuneable Quantum Dot Infrared Photodetectors, Peter Vines, Chee Hing Tan, John P.R. David, Ram S. Attaluri, Thomas E. Vanderveldt, Sanjay Krishna, Woo-Yong Jang, Majeed M. Hayat

Electrical and Computer Engineering Faculty Research and Publications

We report on the implementation of an algorithm-based spectrometer capable of reconstructing the spectral shape of materials in the mid-wave infrared (MWIR) and long-wave infrared (LWIR) wavelengths using only experimental photocurrent measurements from quantum dot infrared photodetectors (QDIPs). The theory and implementation of the algorithm will be described, followed by an investigation into this algorithmic spectrometer's performance. Compared to the QDIPs utilized in an earlier implementation, the ones used here have highly varying spectral shapes and four spectral peaks across the MWIR and LWIR wavelengths. It has been found that the spectrometer is capable of reconstructing broad spectral features of …

Investigation Of Pmma Cement Penetration In Prepared Femoral Heads With A Longitudinal Slot For Hip Resurfacing Arthroplasty, Scott Snyder

Biomedical Engineering

Hip resurfacing arthroplasty is becoming increasingly popular in younger, active patients due to its preservation of natural biomechanics. Failure of these implants can be very traumatic and potentially life threatening. The role of cement penetration in early implant failure is not yet known, and must be investigated. This study specifically investigates the effects of a 5mm by 5mm longitudinal channel on cement penetration into the femoral head. High-density open-cell reticulated vitreous carbon foam cylinders and Huntsman Pro-cast® 20 implants based on the Birmingham Hip Resurfacing implant were used. It was determined cement penetration was increased in the area immediately surrounding …

Pgtp: Power Aware Game Transport Protocol For Multi-Player Mobile Games, Bhojan Anand, Jeena Sebastian, Soh Yu Ming, Akhihebbal L. Ananda, Mun Choon Chan, Rajesh Krishna Balan

Research Collection School Of Computing and Information Systems

Applications on the smartphones are able to capitalize on the increasingly advanced hardware to provide a user experience reasonably impressive. However, the advancement of these applications are hindered battery lifetime of the smartphones. The battery technologies have a relatively low growth rate. Applications like mobile multiplayer games are especially power hungry as they maximize the use of the network, display and CPU resources. The PGTP, presented in this paper is aware of both the transport requirement of these multiplayer mobile games and the limitation posed by battery resource. PGTP dynamically controls the transport based on the criticality of game state …

Exploratory Methods For Truck Re-Identification In A Statewide Network Based On Axle Weight And Axle Spacing Data To Enhance Freight Metrics, Christopher M. Monsere, Mecit Cetin, Andrew Nichols

TREC Final Reports

The main objective of this project is to evaluate the feasibility of re-identifying commercial trucks based on vehicle-attribute data automatically collected by sensors installed at traffic data collection stations. To support this work, archived data from weigh-in-motion (WIM) stations in Oregon are used for developing, calibrating, and testing vehicle re-identification algorithms. The vehicle re-identification methods developed in this research consist of two main stages. In the first stage, each vehicle from the downstream station is matched to the most “similar” upstream vehicle by using a Bayesian model. In the second stage, several methods are introduced to screen out those vehicles …

Design Of Single-Carrier Frequency Domain Equalization (Sc-Fde) With Transmit Diversity For Wireless And Optical Communications, Kodzovi Acolatse

Dissertations

As the demand of wireless service is rising, there is a need to transmit high-speed packets over the wireless communication channel. Broadband data transmission over wireless channels commonly faces the challenges of multipath fading channels, which are both time and frequency selective. There is then a need to design transmission techniques that can combat the adverse effects of the channel, and enable reliable high data rate wireless services. Orthogonal frequency division multiplexing (OFDM) has become widely accepted primarily because of its robustness against frequency selective fading channels, but it suffers a number of drawbacks such as high peak-to-average power ratio …

Risk Based Models For The Optimization Of Oil And Gas Supply Chain Critical Infrastructure, Kingsley Oseloka Achebe

Dissertations

The oil and gas sector faces a broad array of risks and uncertainties, affecting short- and long-term planning, and causing adverse effects in the energy sector. To predict and minimize them, risk based supply chain models were developed for the oil and gas supply chain critical infrastructure.

First, the events and activities were categorized as short term and long term, and their risk ratings derived, by analyzing data from past events and site visits. The result showed that events like the Israel – Arab war, successful hurricane, and production increase or decrease, had a risk rating of approximately 7.

Second, …

Modeling Of Equilibrium Point Trajectory Control In Human Arm Movements, Kai Chen

Dissertations

The underlying concept of the Equilibrium Point Hypothesis (EPH) is that the CNS provides a virtual trajectory of joint motion, representing spacing and timing, with actual movement dynamics being produced by interactions of limb inertia, muscle viscosity and speed/position feedback from muscle spindles. To counter criticisms of the EPH, investigators have proposed the use of complex virtual trajectories, non-linear damping, stiffness and time varying stiffness to the EPH model. While these features allow the EPH to adequately produce human joint velocities, they conflict with the EPH’s premise of simple pre-planned monotonic control of movement trajectory. As a result, this study …

Factors That Impact Seat Belt Usage And Injury Severity Of Belted Front Seat Occupants, Siri Konje Lawrencia Nukenine

Dissertations

Factors influencing seat belt usage have been extensively researched in the safety analysis literature. Most of this research has focused on factors that influence seat belt usage for a driver and front seat passenger in a vehicle. Few research studies have investigated factors that impact seat belt usage for back seat occupants. This research investigates the factors associated with seat belt usage for front-seat as well as backseat occupants of vehicles in the state of New Jersey. Using logistic regression, seat belt usage models were developed to examine the contribution of several variables on seat belt usage for five vehicle …

Application Of Mass/Stiffness Eccentricity To Control Response Of Structures Subjected To Earthquake Ground Motion, Bakhtiar Feizi

Dissertations

This dissertation is driven by the concept that engaging more modes in the response of structures can be used to mitigate its translational dynamic response. One such an approach is to engage torsional modes through engineered eccentricity (mass/stiffness eccentricity), thus, introducing coupled translation-rotation response. This idea was first introduced in a paper published by MacBain and Spillers in 2004. As a follow up to the same idea this dissertation was an attempt to investigate and develop the theory concerning the application of mass/stiffness eccentricity to control the translational motion of structures subjected to earthquake ground motion.

Different discrete and continuous …

Study Of Mechanisms Of Phytotoxicity Of Alumina Nanoparticles, Anthony Elijius

Dissertations

Plant growth inhibitory effect of alumina nanoparticles has recently been reported (Ling Y, Watts D, 2004) but the mechanisms of such an effect are yet to be established. The phytotoxicity of aluminum and some of its compounds is well known, but the rapid expansion of nanotechnology resulting in the introduction of new sets of materials in the nanometer range has led to the development of new approaches, experimental methods and modes of investigation.

In this study, the observed phytotoxic effects of alumina nanoparticles suspension on five plant species (Zea mays, Cucumis sativus, Daucus carota, Brassica oleracea, Lactuca sativa) …

Mixing Of Nanosize Particles By Magnetically Assisted Impaction Techniques, James V. Scicolone

Dissertations

Nanoparticles and nanocomposites offer unique properties that arise from their small size, large surface area, and the interactions of phases at their interfaces, and are attractive for their potential to improve performance of drugs, biomaterials, catalysts and other highvalue- added materials. However, a major problem in utilizing nanoparticles is that they often lose their high surface area due to grain growth. Creating nanostructured composites where two or more nanosized constituents are intimately mixed can prevent this loss in surface area, but in order to obtain homogeneous mixing, de-agglomeration of the individual nanoparticle constituents is necessary.

Due to high surface area, …

Tin/Hfo2/Sio2/Si Gate Stacks Reliability : Contribution Of Hfo2 And Interfacial Sio2 Layer, Nilufa Rahim

Dissertations

Hafnium Oxide based gate stacks are considered to be the potential candidates to replace SiO₂ in complementary metal-oxide-semiconductor (CMOS), as they reduce the gate leakage by over 100 times while keeping the device performance intact. Even though considerable performance improvement has been achieved, reliability of high-κ devices for the next generation of transistors (45nm and beyond) which has an interfacial layer (IL: typically SiO₂) between high-κ and the substrate, needs to be investigated. To understand the breakdown mechanism of high-κ/SiO₂ gate stack completely, it is important to study this multi-layer structure extensively. For example, (i) the …

Distributed Synchronization Algorithms For Wireless Sensor Networks, Nicola Varanese

Dissertations

The ability to distribute time and frequency among a large population of interacting agents is of interest for diverse disciplines, inasmuch as it enables to carry out complex cooperative tasks. In a wireless sensor network (WSN), time/frequency synchronization allows the implementation of distributed signal processing and coding techniques, and the realization of coordinated access to the shared wireless medium. Large multi-hop WSN's constitute a new regime for network synchronization, as they call for the development of scalable, fully distributed synchronization algorithms. While most of previous research focused on synchronization at the application layer, this thesis considers synchronization at the lowest …

Model Reference Control For Ultra-High Precision Positioning Systems, Lan Yu

Dissertations

Due to the increasing demands of high-density semiconductors, molecular biology, optoelectronics, and MEMS/NEMS in the past decades, control of ultra-high precision positioning using piezoelectricity has become an important area because of its high displacement resolution, wide bandwidth, low power consumption, and potential low cost. However, the relatively small displacement range limits its application. This work proposed a practical ultra-high precision piezoelectric positioning system with a complementary high displacement range actuation technology. Solenoids are low cost, high speed electromagnetic actuators which are commonly used in on-off mode only because of the inherent high nonlinear force-stroke characteristics and unipolar forces (push/pull) generated …

Study Of Controlled Release Of Active Pharmaceutical Ingredients From Functionalized Nanoclays And Polymer Matrices, Jin Uk Ha

Dissertations

This dissertation contains the results of three related novel investigations in the field of structure-property-processing relationships of pharmaceutical polymer-based products. They are: a) modification of a pharmaceutical anionic nanoclay with two different Active Pharmaceutical Ingredients (APIs) to produce nanohybrid API carriers intended to be used alone or in acrylic polymer matrices, b) comparison of binary systems containing the above APIs in the selected acrylic polymers in terms of their miscibilities with the polymer, but in the absence of nanoclay, and c) comparison of the polymer/API binary systems with ternary polymer/API/Clay systems.

For the first study, the calcination method which can …

Underwater Communication Via Particle Velocity Channels : Principles, Channel Models, And System Design, Huaihai Guo

Dissertations

A vector sensor is capable of measuring important non-scalar components of the acoustic field such as the particle velocity, which cannot be obtained by a single scalar pressure sensor. In the past few decades, extensive research has been conducted on the theory and design of vector sensors. On the other hand, underwater acoustic communication systems have been relying on scalar sensors only, which measure the pressure of the acoustic field. By taking advantage of the vector components of the acoustic field, such as the particle velocity, the vector sensor can be used for detecting the transmitted data. In this dissertation, …

Seismic Characterization Of Recycled Aggregate Concrete, Amin Jamali

Dissertations

There are significant environmental benefits of recycling waste concrete and reusing it as aggregate for structural concrete, but the use of Recycled Aggregate Concrete (RAC) is yet limited to non-structural applications such as road sub-base. Widespread application of RAC in areas such as seismic design requires an improved knowledge of RAC behavior under multiaxial state of stresses.

The main objective of this research is the characterization of seismic properties of RAC by developing a stress-strain model which can reasonably describe the behavior under both unconfined and confined conditions. An extensive experimental program, including testing of several plain RAC cylinders as …

Dielectrophoresis Aligned Single-Walled Carbon Nanotubes As Ph Sensors, P. Li, C. M. Martin, K. K. Yeung, Wei Xue

Henry M. Rowan College of Engineering Departmental Research

Here we report the fabrication and characterization of pH sensors using aligned single-walled carbon nanotubes (SWNTs). The SWNTs are dispersed in deionized (DI) water after chemical functionalization and filtration. They are deposited and organized on silicon substrates with the dielectrophoresis process. Electrodes with “teeth”-like patterns—fabricated with photolithography and wet etching—are used to generate concentrated electric fields and strong dielectrophoretic forces for the SWNTs to deposit and align in desired locations. The device fabrication is inexpensive, solution-based, and conducted at room temperature. The devices are used as pH sensors with the electrodes as the testing pads and the dielectrophoretically captured SWNTs …

Molecular Dynamics Characterization Of The Contact Between Clean Metallic Surfaces With Nanoscale Asperities, Hojin Kim, Alejandro Strachan

Birck and NCN Publications

We use molecular dynamics (MD) simulations to characterize the tensile strength of contacts formed between various clean platinum surfaces with nanoscale asperities. Both commensurate contacts between (001) and (111) surfaces and incommensurate (001) ones are considered over a wide range of asperity sizes. In cyclic closing and opening, fresh asperities that form contacts for the first time show significant plastic deformation; this leads to a reduction in the effective contact area during the first few cycles, after which steady state is achieved both in terms of contact size and the pull-out force necessary to open the contacts. As is the …