Engineering Commons^™

Study Of Modified Deposition Process For Cu(In,Ga)Se2 Solar Cell Back Contact, Tasnuva Ashrafee

Electrical & Computer Engineering Theses & Dissertations

As the worldwide demand for renewable energy is increasing, growth of the global share of alternative energy sources would improve overall energy security as well as bring environmental benefits. So far, solar cells - the devices that convert direct sunlight into electricity - are dominated by silicon devices. Another alternative is thin film solar cell, whose main inspiration is to reduce the electricity production cost. Cu(In, Ga)Se₂ (CIGS) solar cells are considered to have a great prospective because of reduced material and energy consumption during manufacturing. Many CIGS solar cell manufacturers are already exhibiting GW-scale production capacity. With the …

Diffusion Modeling Of Impurities Through The Molybdenum Back Contact Of Cigs Solar Cells, Chinedum John Akwari

Electrical & Computer Engineering Theses & Dissertations

CIGS is a major technology in photovoltaics and depends heavily, as any other PV technology, on the capacity to achieve the highest efficiency possible to compete on the market. Alkaline elements, notably sodium and potassium, play a key role in this matter as they enhance the open circuit voltage and the fill factor of the CIGS solar cells. However, this effect exists only for very specific concentration of sodium and potassium. These impurities typically diffuse through the soda-lime glass substrate.

Via modeling of the SIMS data, we try to understand and predict the diffusion mechanisms of these impurities from the …

Enhancement Of Thermoelectric Properties Of Ald Synthesized Pbte And Pbse By Phonon Engineering, Xin Chen

Electrical & Computer Engineering Theses & Dissertations

Thermoelectrics is a green renewable energy technology that plays an important role in power generation due to its potential in generating electricity out of waste heat. The main challenge for the development of thermoelectrics is its low conversion efficiency. One key strategy to improve conversion efficiency is focused on reducing the thermal conductivity of thermoelectric materials. In this thesis, the novel phononic engineering concept was implemented by conformal ALD deposition of PbTe, PbSe thermoelectric films, and PbTe/PbSe nanolaminates on patterned silicon substrates in order to improve the thermoelectric performance of the thermoelectric films. The silicon substrates were lithographically patterned with …

A Correlational Study Of Sansec Sensors’ Electric Field Distribution On Lightning Attachment, Kayla M. Farrow

Electrical & Computer Engineering Theses & Dissertations

Old Dominion University and the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) Aviation Safety Program Atmospheric Environmental Safety Technologies Project team conducted research in using SansEC (Sans Electric Connection) sensors to provide lightning strike protection (LSP) and damage mitigation for composite aircraft. SansEC sensors are simplistic devices consisting of an open circuit conductive trace, shaped in a planar geometric spiral [1], [2], [3]. SansEC sensors can be designed in various shapes and sizes depending on the application. For applications on exterior aircraft surfaces, the sensor must be designed to perform the required lightning strike protection [1], [3]. …

Methodology To Perform Cyber Lethality Assessment, Matthew W. Zurasky

Engineering Management & Systems Engineering Theses & Dissertations

The Naval Surface Warfare Center, Dahlgren Division (NSWCDD) Lethality and Effectiveness Branch is the Navy’s subject matter experts (SME) on target vulnerability, weapon lethality, and weapon effectiveness. Branch personnel currently exercise expertise in the kinetic and directed energy weapon domains. When the Navy develops weapons in the kinetic and directed energy domains, there are clear and well established procedures and methodologies for performing target characterization that support weapon-target pairing. Algorithms exist to describe the likelihood of damage effects. It is natural that in the paradigm shift to cyberspace warfare that the Branch provide these same services to the warfighter in …

Modeling Dormant Fruit Trees For Agricultural Automation, Henry Medeiros, Donghun Kim, Jianxin Sun, Hariharan Seshadri, Shayan A. Akbar, Noha M. Elfiky, Johnny Park

Electrical and Computer Engineering Faculty Research and Publications

Dormant pruning of fruit trees is one of the most costly and labor‐intensive activities in specialty crop production. We present a system that solves the first step in the process of automated pruning: accurately measuring and modeling the fruit trees. Our system employs a laser sensor to collect observations of fruit trees from multiple perspectives, and it uses these observations to measure parameters needed for pruning. A split‐and‐merge clustering algorithm divides the collected data into three sets of points: trunk candidates, junction point candidates, and branches. The trunk candidates and junction point candidates are then further refined by a robust …

Optimization Of Patch Antennas Via Multithreaded Simulated Annealing Based Design Exploration, James Richie, Cristinel Ababei

Electrical and Computer Engineering Faculty Research and Publications

In this paper, we present a new software framework for the optimization of the design of microstrip patch antennas. The proposed simulation and optimization framework implements a simulated annealing algorithm to perform design space exploration in order to identify the optimal patch antenna design. During each iteration of the optimization loop, we employ the popular MEEP simulation tool to evaluate explored design solutions. To speed up the design space exploration, the software framework is developed to run multiple MEEP simulations concurrently. This is achieved using multithreading to implement a manager-workers execution strategy. The number of worker threads is the same …

Effect Of Bioglass Incorporation Into Electrochemically Aligned Collagen Threads On Mechanical Properties And Cell-Mediated Mineralization, Madhura Nijsure

Theses and Dissertations

Bone related diseases and disorders are a significant socioeconomic burden in the United States. Autografts and allografts are most commonly used for the treatment of bone defects and non-unions; however, they are associated with limitations such as donor site morbidity and immune rejection, respectively. Over the past few decades, bone tissue engineering (BTE) using scaffold and cells has garnered significant interest as an alternative method for the repair and regeneration of bone defects. Recreation of the tissue microenvironment via the development of biomimetic scaffolds that resemble the physicochemical aspects (i.e., composition, topography, stiffness) of native bone is a promising approach …

K-Bit-Swap: A New Operator For Real-Coded Evolutionary Algorithms, Aram Ter-Sarkisov, Stephen Marsland

Articles

There has been a variety of crossover operators proposed for Real-Coded Genetic Algorithms (RCGAs), which recombine values from the same location in pairs of strings. In this article we present a recombination operator for RC- GAs that selects the locations randomly in both parents, and compare it to mainstream crossover operators in a set of experiments on a range of standard multidimensional optimization problems and a clustering problem. We present two variants of the operator, either selecting both bits uniformly at random in the strings, or sampling the second bit from a normal distribution centered at the selected location in …

Use Of A Novel Infrared Wavelength-Tunable Laser Mueller-Matrix Polarimetric Scatterometer To Measure Nanostructured Optical Materials, Jason C. Vap, Stephen E. Nauyoks, Michael R. Benson, Michael A. Marciniak

Faculty Publications

Nanostructured optical materials, for example, metamaterials, have unique spectral, directional, and polarimetric properties. Samples designed and fabricated for infrared (IR) wavelengths have been characterized using broadband instruments to measure specular polarimetric transmittance or reflectance as in ellipsometry or integrated hemisphere transmittance or reflectance. We have developed a wavelength-tunable IR Mueller-matrix (Mm) polarimetric scatterometer which uses tunable external-cavity quantum-cascade lasers (EC-QCLs) to tune onto and off of the narrowband spectral resonances of nanostructured optical materials and performed full polarimeteric and directional evaluation to more fully characterize their behavior. Using a series of EC-QCLs, the instrument is tunable over 4.37-6.54 μm wavelengths …

Nanowire-Based Light-Emitting Diodes: A New Path Towards High-Speed Visible Light Communication, Mohsen Nami

Physics & Astronomy ETDs

Nano-scale optoelectronic devices have gained significant attention in recent years. Among these devices are semiconductor nanowires, whose dimeters range from 100 to 200 nm. Semiconductor nanowires can be utilized in many different applications including light-emitting diodes and laser diodes. Higher surface to volume ratio makes nanowire-based structures potential candidates for the next generation of photodetectors, sensors, and solar cells. Core-shell light-emitting diodes based on selective-area growth of gallium nitride (GaN) nanowires provide a wide range of advantages. Among these advantages are access to non-polar m-plane sidewalls, higher active region area compared to conventional planar structures, and reduction of threading …

Design Of Dc-Link Vscf Ac Electrical Power System For The Embraer 190/195 Aircraft, Eduardo Francis Carvalho Freitas, Nihad E. Daidzic

Journal of Aviation Technology and Engineering

A proposed novel DC-Link VSCF AC-DC-AC electrical power system converter for Embraer 190/195 transport category airplane is presented. The proposed converter could replace the existing conventional system based on the CSCF IDGs. Several contemporary production airplanes already have VSCF as a major or backup source of electrical power. Problems existed with the older VSCF systems in the past; however, the switched power electronics and digital controllers have matured and can be now, in our opinion, safely integrated and replace existing constant-speed hydraulic transmissions powering CSCF AC generators. IGBT power transistors for medium-level power conversion and relatively fast efficient switching are …

Vfr-Into-Imc: An Analysis Of Two Training Protocols On Weather-Related Posttest Scores, Julius C. Keller, Thomas Carney, Allen Xie, Wesley Major, Matt Price

Journal of Aviation Technology and Engineering

According to the Aircraft Owners and Pilots Association Air Safety Institute, 264 accidents were identified as continued visual flight rules (VFR) into instrument meteorological conditions (IMC), during the past ten years. Approximately 89% of those VFR-into-IMC accidents were fatal, causing hundreds of deaths. VFR-into-IMC has been a major concern for the general aviation community, prompting focused efforts. Research, data analyses, outreach, training, and education are recommended practices to address risks associated with VFR-into-IMC. Researchers of the current study sought to evaluate the cause and effect relationship between two training protocols and weather-related posttest scores. A pretest–posttest experimental design was utilized …

Torrefaction Kinetics Of Hemp Hurds, An Emerging Agricultural Byproduct, In A Small Retort, Tel Jensen

Civil and Environmental Engineering Undergraduate Honors Theses

As knowledge concerning the consequences of unsustainable energy sources and agricultural practices grows, development of low-impact alternatives to both becomes more important. Sustainable sources of biomass offer solutions to both problems. This study characterized the reaction kinetics of torrefying an agricultural byproduct, the woody interior of hemp stems, or hurds. Torrefaction was carried out at 250 °C in small and simple retorts made of galvanized steel pipe. A first-order model most closely approximated the reaction. A sensitivity analysis was performed and the data was adjusted to correct for three potential sources of error, and regressed to find the best fit …

The Beauty Of Fluid Dynamics | College Of Engineering, Usu College Of Engineering

College of Engineering News

Tadd Truscott is an MIT-trained engineer of fluid dynamics – a profession steeped in dizzying mathematics and complex physics.

Star Light, Star Blight | College Of Engineering, Usu College Of Engineering

College of Engineering News

Humans have been rocketing themselves and their stuff into space for more than half a century.

Increased Span Length For The Mgs Long-Span Guardrail System Part Iii: Failure Analysis, Sagheer A. Ranjha, Robert W. Bielenberg, John D. Reid, Ronald K. Faller

Nebraska Department of Transportation: Research Reports

The objective of this research study was to review and analyze the system failure observed during crash testing of an increased span length for the MGS long-span guardrail system in test no. MGSLS-2. Test no. MGSLS-2 was a full-scale crash test conducted on the MGS long-span guardrail with a span length of 311⁄4 ft (9.5 m). This test utilized universal breakaway steel posts (UBSPs) adjacent to the long span in lieu of the controlled release terminal (CRT) wood posts used in previous long span systems.

An engineering analysis was undertaken to review the downstream end anchorage failure observed in test …

The Shifting Discourse On Third Places: Ideological Implications, Mark N. Wexler, Judy Oberlander

Journal of Ideology

Within the social sciences, literature on third places attempts to assist in the construction of a social concept of “place”. This notion of a place is an idealization of the bridging space with home and family on one side, and work with the rule-based impersonality of life in mass society, on the other. Like the idea of work-life balance—as seen through the vocabulary of placemaking—third places provide people with a place in which there is a balance between the emotive attachments of home and family and the challenge striving for merit and reward in the marketplace. To date, third places …

Two Dimensional Grating Magneto-Optical Trap, Eric A. Imhof, Benjamin K. Stuhl, Brian Kasch, Bethany Kroese, Spencer E. Olson, Matthew B. Squires

Space Dynamics Laboratory Publications

We demonstrate a two-dimensional grating magneto optical trap (2D GMOT) with a single input beam and a planar diffraction grating in ⁸⁷Rb. This configuration allows for an increase in experimental access when compared with a traditional 2D MOT. As configured in the paper, the output flux is > 4 × 10⁸ rubidium atoms/s at a mean velocity of 18 m/s. The velocity distribution has a 3 m/s standard deviation. We use the atomic beam from the 2D GMOT to demonstrate loading of a three dimensional grating MOT (3D GMOT) with 2 × 10⁸ atoms. Methods to improve flux …

Shear Joy Of Watching Paint Dry, Randy Craig Hurd, Nathan B. Spiers, J. Belden, Zhao Pan, B. Lovett, W. G. Robinson, M. A. Zamora, Saberul I. Sharker, Mohammad M. Mansoor, A. Merritt, Tadd T. Truscott

Mechanical and Aerospace Engineering Faculty Publications

This paper is associated with a video winner of a 2016 APS/DFD Milton van Dyke Award for work presented at the DFD Gallery of Fluid Motion.

Spin-Imbalance In A 2d Fermi-Hubbard System, Peter Brown, Debayan Mitra, Elmer Guardado-Sanchez, Peter Schauß, Stanimir Kondov, Ehsan Khatami, Thereza Paiva, Nandini Trivedi, David Huse, Waseem Bakr

Faculty Publications

The interplay of strong interactions and magnetic fields gives rise to unusual forms of superconductivity and magnetism in quantum many-body systems. Here, we present an experimental study of the two-dimensional Fermi-Hubbard model—a paradigm for strongly correlated fermions on a lattice—in the presence of a Zeeman field and varying doping. Using site-resolved measurements, we revealed anisotropic antiferromagnetic correlations, a precursor to long-range canted order. We observed nonmonotonic behavior of the local polarization with doping for strong interactions, which we attribute to the evolution from an antiferromagnetic insulator to a metallic phase. Our results pave the way to experimentally mapping the low-temperature …

Lab-On-Sensor For Structural Behavior Monitoring: Theory And Applications, Genda Chen

INSPIRE Archived Webinars

There are over 600,000 bridges in the U.S. National Bridge Inventory (NBI). Nearly 50% of them rapidly approach their design life and deteriorate at an alarming rate, particularly under an increasing volume of overweight trucks. Visual inspection as the current practice in bridge management is labor intensive and subjective, resulting in inconsistent and less reliable element ratings. Lab-on-sensor technologies can provide supplemental mission-critical data to the visual inspection for both qualitative and quantitative evaluations of structural conditions, and thus critical decision-making of cost-effective strategies in bridge preservation.

In this presentation, the design and operation characteristics of highway bridges are first …

The Study Of Superheavy Elements At The Intensity Frontier: Reactions And New Methods Of Synthesis, Devaraja H. M

University Departments

No abstract provided.

The Santa Clara, 2017-09-28, Santa Clara University

The Santa Clara

No abstract provided.

Enzyme Shielding In A Soft Organo-Silica Layer – Pharma/Biopharma Applications, Yves Dudal, Federica Richina, Lucas Durandi, Rita Correro, Patrick Shahgaldian

Enzyme Engineering XXIV

Enzymes, or biocatalysts, are specialty proteins. Like antibodies to antigens, enzymes exhibit remarkable specificity for their substrate and naturally facilitate many chemical conversions. However, the use of enzymes in the biotech industry ($2.3bn) is strongly limited by the fact that enzymes are highly sensitive like most proteins and usually not fitted to in vivo and process conditions. Many expensive genetically engineered or biosourced enzymes show remarkable properties but need to be made more robust for deployment in the health industry.

We have developed a unique procedure to fit enzymes to in vivo and process conditions. The process is initiated by …

Increased Trans-Glycosylation Activity Of Hexosaminidases For Synthesis Of Human Milk Oligosaccharides, Jan Muschiol, Jesper Holck, Peter K. Busk, Lene Lange, Jørn D. Mikkelsen, Anne S. Meyer, Shariza B. Jamek,

Enzyme Engineering XXIV

It is well known that the composition of human breast milk differs significantly from the one of ordinary bovine milk. Especially the presence of sialylated and fucosylated oligosaccharides contributes to its health and development promoting features for newborn infants. [1] Nevertheless, not all newborns and especially premature infants sometimes cannot be breast fed for different reasons. For those children it is important that they receive a proper balanced formula product containing the above mentioned human milk oligosaccharides (HMOs). With respect to this we are developing new enzymatic routes for synthesis of sialylated and fucosylated oligosaccharides, which can be used as …

Information Technology News, Georgia Southern University

Information Technology: News & Publications (2012-2023)

• Georgia Southern Ranks 5th in the 2018 Top Online IT Degrees

Approaches To Integrating Engineering In Stem Units And Student Achievement Gains, Elizabeth A. Crotty, Selcen S. Guzey, Gillian H. Roehrig, Aran W. Glancy, Elizabeth A. Ring-Whalen, Tamara J. Moore

Journal of Pre-College Engineering Education Research (J-PEER)

This study examined different approaches to integrating engineering practices in science, technology, engineering, and mathematics (STEM) curriculum units. These various approaches were correlated with student outcomes on engineering assessment items. There are numerous reform documents in the USA and around the world that emphasize the need to incorporate engineering into science education. The authors of this study contend that different approaches to integrating engineering in STEM units correlate to larger student achievement gains in engineering, based on assessment items developed from the Framework for Quality K–12 Engineering Education (Moore, Glancy, Tank, Kersten, & Smith, 2014). The goal of this work …

Usu To Lead $4m Collaborative Water Research Initiative | College Of Engineering, Usu College Of Engineering

College of Engineering News

Utah State University hydrologists are revolutionizing the way scientific data is stored and shared among scientists around the globe.

The Comprehensive Handling Of Safety In An Autonomous Robot Capstone Project, John G. Ciezki, Steve Eugene Watkins

Electrical and Computer Engineering Faculty Research & Creative Works

A systematic approach to safety issues is described in the context of an autonomous robot capstone project. The treatment of safety should not be an ad hoc or an after-thought aspect of design projects. Engineering students need to consider safety as an integral component of the design process and to identify and address hazards systematically in each stage of project work. Appropriate actions include researching professional standards and regulations, incorporating safety best practices, developing safety checklists and operating protocols, and providing significant safety documentation. Formal safety components were added to a capstone design project for electrical and computer engineering undergraduates …