Engineering Commons^™

Arrow-Based On-Chip Alkali Vapor-Cell Development, John Frederick Hulbert

Theses and Dissertations

The author presents the successful development of an on-chip, monolithic, integrated rubidium vapor-cell. These vapor-cells integrate ridge waveguide techniques with hollow-core waveguiding technology known as Anti-Resonant Reflecting Optical Waveguides (ARROWs). These devices are manufactured on-site in BYU's Integrated Microelectronic Laboratory (IML) using common silicon wafer microfabrication techniques. The ARROW platform fabrication is outlined, but the bulk of the dissertation focuses on novel packaging techniques that allow for the successful introduction and sealing of rubidium vapor into these micro-sized vapor-cells. The unique geometries and materials utilized in the ARROW platform render common vapor-cell sealing techniques unusable. The development of three generations …

Cross-Plane Thermoelectric Transport In P-Type La0.67sr0.33mno3/Lamno3 Oxide Metal/Semiconductor Superlattices, Pankaj Jha, Timothy D. Sands, Philip Jackson, Cory Bomberger, Tela Favaloro, Stephen Hodson, Joshua Zide, Xianfan Xu, Ali Shakouri

Birck and NCN Publications

The cross-plane thermoelectric transport properties of La0.67Sr0.33MnO3 (LSMO)/LaMnO3 (LMO) oxide metal/semiconductor superlattices were investigated. The LSMO and LMO thin-film depositions were performed using pulsed laser deposition to achieve low resistivity constituent materials for LSMO/LMO superlattice heterostructures on (100)-strontium titanate substrates. X-ray diffraction and high-resolution reciprocal space mapping indicate that the superlattices are epitaxial and pseudomorphic. Cross-plane devices were fabricated by etching cylindrical pillar structures in superlattices using inductively, this coupled-plasma reactive-ion etching. The crossplane electrical conductivity data for LSMO/LMO superlattices reveal a lowering of the effective barrier height to 223 meV as well as an increase in cross-plane conductivity by …

Direct Pulsed Laser Crystallization Of Nanocrystals For Absorbent Layers In Photovoltaics: Multiphysics Simulation And Experiment, Martin Y. Zhang, Qiong Nian, Yung Shin, Gary J. Cheng

Birck and NCN Publications

Direct pulsed laser crystallization (DPLC) of nanoparticles of photoactive material-Copper Indium Selenide (nanoCIS) is investigated by multiphysics simulation and experiments. Laser interaction with nanoparticles is fundamentally different from their bulk counterparts. A multiphysics electromagnetic-heat transfer model is built to simulate DPLC of nanoparticles. It is found smaller photoactive nanomaterials (e.g., nanoCIS) require less laser fluence to accomplish the DPLC due to their stronger interactions with incident laser and lower melting point. The simulated optimal laser fluence is validated by experiments observation of ideal microstructure. Selectivity of DPLC process is also confirmed by multiphysics simulation and experiments. The combination effects of …

Photonically Excited Electron Emission From Modified Graphitic Nanopetal Arrays, Patrick T. Mccarthy, Scott J. Vander Laan, David B. Janes, Timothy S. Fisher

Birck and NCN Publications

Efficient electron emission for energy conversion requires a low work function and a stable emitter material. The work function of graphene-based carbon materials can decrease significantly by intercalation with alkali metals, thus increasing their emission current. In this work, electron emission from potassium-intercalated carbon nanosheet extensions grown on electrode graphite is investigated. These petal-like structures, composed of 5-25 layers of graphene, are synthesized using microwave plasma chemical vapor deposition. Samples are intercalated with potassium, and a hemispherical energy analyzer is used to measure the emission intensity caused by both thermal and photonic excitation. The emission from the potassium-intercalated structures is …

Micro Modeling Study Of Cathode/Electrolyte Interfacial Stresses For Solid Oxide Fuel Cells, Xinfang Jin, Xingjian Xue

Faculty Publications

Delamination of the cathode/electrolyte interface is an important degradation phenomenon in solid oxide fuel cells (SOFCs). While the thermal stress has been widely recognized as one of the major reasons for such delamination failures, the role of chemical stress does not receive too much attention. In this paper, a micro-model is developed to study the cathode/electrolyte interfacial stresses, coupling oxygen ion transport process with structural mechanics. Results indicate that the distributions of chemical stress are very complicated at the cathode/electrolyte interface and show different patterns from those of thermal stress. The maximum principal stresses take place at the cathode/electrolyte interface …

Long-Term Low Do Enriches And Shifts Nitrifier Community In Activated Sludge, Guoqiang Liu, Jianmin Wang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In the activated sludge process, reducing the operational dissolved oxygen (DO) concentration can improve oxygen transfer efficiency, thereby reducing energy use. The low DO, however, may result in incomplete nitrification. This research investigated the long-term effect of low DO on the nitrification performance of activated sludge. Results indicated that, for reactors with 10- and 40-day solids retention times (SRTs), complete nitrification was accomplished after a long-term operation with a DO of 0.37 and 0.16 mg/L, respectively. Under long-term low DO conditions, nitrite oxidizing bacteria (NOB) became a better oxygen competitor than ammonia oxidizing bacteria (AOB) and, as a result, no …

Modeling A Sensor To Improve Its Efficacy, Nabin K. Malakar, Daniil Gladkov, Kevin H. Knuth

Physics Faculty Scholarship

Robots rely on sensors to provide them with information about their surroundings. However, high-quality sensors can be extremely expensive and cost-prohibitive. Thus many robotic systems must make due with lower-quality sensors. Here we demonstrate via a case study how modeling a sensor can improve its efficacy when employed within a Bayesian inferential framework. As a test bed we employ a robotic arm that is designed to autonomously take its own measurements using an inexpensive LEGO light sensor to estimate the position and radius of a white circle on a black field. The light sensor integrates the light arriving from a …

Hs3dpg: Hierarchical Simulation For 3d P/G Network, Shuai Tao, Xiaoming Chen, Yu Wang, Yuchun Ma, Yiyu Shi

Electrical and Computer Engineering Faculty Research & Creative Works

As different chips are stacked together in 3D ICs, the power/ground (P/G) network simulation becomes more challenging than that of 2D cases. In this paper, we propose a hierarchical simulation method suitable for 3D P/G network (HS3DPG), which can ensure full parallelism and good scalability with the number of tiers. In the IR drop analysis, when there are 9 tiers, the hierarchical method can be 6.5 times faster than the direct full network simulation. The accuracy of HS3DPG has been verified by a 3D P/G network from the industrial design. Besides, we introduce the 'locality' property into HS3DPG to further …

Community Approaches To Hydrologic Data And Model Sharing Using Cloud Resources, David G. Tarboton, R. Idaszak, Jeffery S. Horsburgh, Daniel Ames, J. Goodall, L. Band, V. Merwade, A. Couch, J. Arrigo, R. P. Hooper, D. W. Valentine

Civil and Environmental Engineering Faculty Publications

Cloud Computing

The CUAHSI HIS

• A Services-Oriented Architecture Based System for Sharing Hydrologic Data

HydroShare

• A Web-Based Collaborative Environment for the Sharing of Hydrologic Data and Models

Device Engineering For Infectious Disease Diagnosis Using Isothermal Dna Amplification And Lateral Flow Detection, Kristina Roskos

KGI Theses and Dissertations

Technologies that enable infectious diseases diagnosis in low-resource settings could greatly facilitate effective treatment and containment of such diseases. Nucleic acid amplification testing can be used to identify pathogens, but typically requires highly-trained personnel and large, expensive lab equipment, neither of which is available in low-resource settings. Our overall goal is to develop a portable diagnostic system that utilizes a low-cost, disposable, mesofluidic cartridge and a handheld electronics unit to perform fully-integrated nucleic acid testing at the point of care in low-resource settings. As a first step toward this goal, we developed a subunit to execute isothermal nucleic acid amplification …

Visible-Light Photoresponse Of Aln-Based Film Bulk Acoustic Wave Resonator, Changjian Zhou, Yi Yang, Y. Shu, Hualin Cai, Tian-Ling Ren, Mansun Chan, J. Zhou, Hao Jin, Shurong Dong, Cary Y. Yang

Electrical and Computer Engineering

Visible-light photoresponse of an AlN-based film bulk acoustic wave resonator (FBAR) is demonstrated. It is found that the FBAR exhibits a resonant frequency downshift under purple light illumination and the magnitude of the frequency downshift increases as the power density increases within the range of 5–40 mW/cm². A resonant frequency downshift of 1313 KHz is observed under 40 mW/cm² illumination, corresponding to a minimum detection power of 6.09 nW. A sub-bandgap photoresponse of the AlN thin film is proposed to explain this phenomenon.

Increasing Round Trip Efficiency Of Hybrid Li-Air Battery With Bifunctional Catalysts, Kan Huang, Yunfeng Li, Yangchuan Xing

Chemical and Biochemical Engineering Faculty Research & Creative Works

Previously it was shown that Pt as cathode catalyst has a large overpotential during charge in rechargeable hybrid Li-air battery with sulfuric acid catholyte. This article demonstrates that a bifunctional catalyst composed of Pt and IrO2 supported on carbon nanotubes can address this problem. The specially designed and synthesized bifunctional catalyst showed significant overpotential reduction and achieved a round-trip energy efficiency of 81% after 10 cycles, higher than many achieved in aprotic Li-O2 batteries. The hybrid Li-air battery was discharged and recharged for 20 cycles at 0.2 mA/cm2, showing a fairly stable cell performance. A specific capacity of 306 mAh/g …

The Fundamentals Of A Course On The Environmental Impacts Of Ships, Patricia A. Coker

LSU New Orleans Theses and Dissertations

No abstract provided.

Stress Analysis Of Ramberg-Osgood And Hollomon 1-D Axial Rods, Ronald J. Giardina Jr

LSU New Orleans Theses and Dissertations

In this paper we present novel analytic and finite element solutions to 1-D straight rods made of Ramberg-Osgood and Hollomon type materials. These material models are studied because they are a more accurate representation of the material properties of certain metals used often in manufacturing than the simpler composite linear types of stress/strain models. Here, various types of loads are considered and solutions are compared against some linear models. It is shown that the nonlinear models do have manageable solutions, which produce important differences in the results - attributes which suggest that these models should take a more prominent place …

Nanomaterials For Biological Applications: Drug Delivery And Bio-Sensing, Hui Ma

LSU New Orleans Theses and Dissertations

The idea of utilizing nanomaterials in bio-related applications has been extensively practiced during the recent decades. Magnetic nanoparticles (MPs), especially superparamagnetic iron oxide nanoparticles have been demonstrated as promising candidates for biomedicine. A protective coating process with biocompatible materials is commonly performed on MPs to further enhance their colloidal and chemical stability in the physiological environment. Mesoporous hollow silica is another class of important nanomaterials that are extensively studied in drug delivery area for their ability to carry significant amount of guest molecules and release in a controlled manner.

In this study, different synthetic approaches that are able to produce …

Innovation In Ship Design, Christopher B. Mckesson

LSU New Orleans Theses and Dissertations

What is innovation in ship design? Is it a capability that is inherent in all naval architects? Is it the result of the application of a certain set of tools, or of operation within a certain organizational structure? Can innovation be taught?

Innovation is a creative act that results in a new and game-changing product. The emergence of an innovative product creates an asymmetric market. The emergence of an innovative weapon creates an asymmetric battlefield. It is clearly in the economic and military interest of the United States to be able to develop and deploy innovative products, including innovative ships. …

Fatigue Testing And Data Analysis Of Welded Steel Cruciform Joints, Alina Shrestha

LSU New Orleans Theses and Dissertations

In this study, ABS Publication 115, “Guidance on Fatigue Assessment of Offshore Structures” is briefly reviewed. Emphasis is on the S-N curves based fatigue assessment approach of non-tubular joints, and both size and environment effects are also considered. Further, fatigue tests are performed to study the fatigue strength of load-carrying and non-load-carrying steel cruciform joints that represent typical joint types in marine structures. The experimental results are then compared against ABS fatigue assessment methods, based on nominal stress approach, which demonstrates a need for better fatigue evaluation parameter. A good fatigue parameter by definition should be consistent and should correlate …

Studies On Structure And Property Of Polymer-Based Nano-Composite Materials, Yun Zhai

LSU New Orleans Theses and Dissertations

The mixing of polymers and nanoparticles makes it possible to give advantageous macroscopic material performance by tailoring the microstructure of composites. In this thesis, five combinations of nano inclusion and polymer matrix have been investigated.

The first type of composites is titanium dioxide/ polyaniline combination. The effects of 4 different doping-acids on the microstructure, morphology, thermal stability and thermoelectric properties were discussed, showing that the sample with HCl and sulfosalicylic dual acids gave a better thermoelectric property. The second combination is titanium dioxide/polystyrene composite. Avrami equation was used to investigate the crystallization process. The best fit of the mass derivative …

Developing A Strategic Policy Choice Framework For Technological Innovation: Case Of Chinese Pharmaceuticals, Leong Chan

Dissertations and Theses

With the growing trend of globalization and rapid development of high technologies, emerging economies face more challenges in technology development because they are chasing a fast-moving frontier. They need to identify global technology trends and adapt to local needs and capabilities. Strategies for technology development differ among countries at different developmental stages.

In this research, a technology policy choice framework is developed to link prospective high-tech areas, technology development strategies, and various innovative resources. The research approach is to develop a hierarchical decision model (HDM) and apply the analytic hierarchical process (AHP). Experts are invited from diverse sources to provide …

A Mathematical Model For Quantifying System Evolvability Using Excess And Modularity, Morgan Wesley Parry Tackett

Theses and Dissertations

An important factor in system longevity is service-phase evolvability, which is defined as the ability of a system to physically transform from one configuration to a more desirable configuration while in service. These transformations may or may not be known during the design process, and may or may not be reversible. A study of 210 engineered systems was performed and found that system excess and modularity allow a system to evolve while in service. Building on these observations, this thesis introduces mathematical relationships that map a system's excess and modularity to that system's ability to evolve. These relationships are derived …

The Effects Of A Collaborative Problem-Based Learning Experience On Students’ Motivation In Engineering Capstone Courses, Brett D. Jones, Cory M. Epler, Parastou Mokri, Lauren H. Bryant, Marie C. Paretti

Interdisciplinary Journal of Problem-Based Learning

We identified and examined how the instructional elements of problem-based learning capstone engineering courses affected students’ motivation to engage in the courses. We employed a two-phase, sequential, explanatory, mixed methods research design. For the quantitative phase, 47 undergraduate students at a large public university completed a questionnaire that measured the components of the MUSIC Model of Academic Motivation (Jones, 2009): empowerment, usefulness, success, situational interest, individual interest, academic caring, and personal caring. For the qualitative phase that followed, 10 students answered questions related to the MUSIC components. We identified several instructional elements that led to motivating opportunities that affected students’ …

The Santa Clara, 2013-05-16, Santa Clara University

The Santa Clara

No abstract provided.

Innovation Measurement: A Decision Framework To Determine Innovativeness Of A Company, Kenny Phan

Dissertations and Theses

Innovation is one of the most important sources of competitive advantage. It helps a company to fuel the growth of new products and services, sustain incumbents, create new markets, transform industries, and promote the global competitiveness of nations. Because of its importance, companies need to manage innovation. It is very important for a company to be able to measure its innovativeness because one cannot effectively manage without measurement. A good measurement model will help a company to understand its current capability and identify areas that need improvement.

In this research a systematic approach was developed for a company to measure …

Dynamic Poverty Heat Map, Jonathan Ahumada, Kurt Jurgens, Jasmine Farias

Computer Science and Engineering Senior Theses

Data management and analysis can become an overwhelming task when having to deal with large amounts of data. Fundación Paraguaya (FP), an organization that aims at reducing poverty in Paraguay, currently has been facing this data readability issue. The data from electronic surveys conducted by FP to measure poverty levels in different areas of Paraguay are currently presented in a complex and overwhelming manner via Excel spreadsheet. This method of data representation increases the risk of committing errors, as well as slows down the process of efficiently locating the areas of greatest needs and allocating the resources to these areas. …

Kevin Kennedy Recognized As Ece Department Outstanding Pre-Professional Student | Utah State University Power Electronics Lab, Usu College Of Engineering

College of Engineering News

Kevin was recognized by the Electrical and Computer Engineering department as this year's Outstanding Pre-Professional Student. This award is given each year at the Pre-Professional, Junior and Senior level by a comittee which selects each student from among their top peers. Kevin is an undergraduate research student at UPEL, where he is assisting development and hardware evaluation of high performance bidirectional DC-DC power converters as part of a contract with Raytheon and the Office of Naval Research.

Using Topology Optimization To Numerically Improve Barriers To Reverse Engineering, Devin Donald Lebaron

Theses and Dissertations

Here explored is a method by which designers can use the tool of topology optimization to numerically improve barriers to reverse engineering. Recently developed metrics, which characterize the time (T) to reverse engineer a product, enable this optimization. A key parameter use din the calculation of T is information content (K). The method presented in this thesis pursues traditional topology optimization objectives while simultaneously maximizing K, and thus T, in the resulting topology. This thesis presents new algorithms to 1) evaluate K for any topology, 2)increase K for a topology by manipulating macro-scale geometry and micro-scale crystallographic information for each …

Nonlinearity Analysis And Predistortion Of 4g Wireless Communication Systems, Xiao Li

Dissertations and Theses

The nonlinearity of RF power amplifiers (PA) is one of critical concerns for RF designers because it causes spectral regrowth related to in-band and out-of-band spurious emissions control in communication standards. Traditionally, RF power amplifiers must be backed off considerably from the peak of their power level in order to prevent spectral regrowth. The digital predistortion (DPD) technique is being widely used for compensation of the nonlinearity of RF power amplifiers, as the high power efficiency becomes increasely important in wireless communication systems.

However, the latest generations of communication systems, such as Wi-Fi, WiMAX, and LTE, using wider bandwidth have …

Stormwater Harvesting Using Retention And In-Line Pipes For Treatment Consistent With The New Statewide Stormwater Rule, Martin Wanielista, Mike Hardin, Ikiensinma Gogo-Abite, Manoj Chopra

BMP Trains Research and Publications

Stormwater rules and regulations are evolving. Thus, there is a need for research that supports alternative methods for water quality treatment of runoff water. The information in this report supports the use of filtration media called Biosorption Activated Media (BAM) that improves runoff water quality. Runoff to impaired waters may need additional treatment or reduced volume of discharge to meet a mass discharge limitation. In addition, some nutrients in runoff waters may need to be removed before they percolate to nutrient sensitive areas such as aquifers with discharge to springs or estuaries. Thus, stormwater harvesting or reuse is another best …

Smaller Spacecraft For Education And Space Research, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Professor Bob Twiggs titled "Smaller spacecraft for education and space research" from May 14, 2013.

Micro-Jet Cooling Of Cutting Tools, Douglas J. Woodruff, Gary W. Pannala, William J. Endres, Nicole Barna, Quincy Schultz, David Thomasini, Matthew Zblewski

Michigan Tech Patents

A cutting tool includes an insert defining a flank face, a rake face, and a cutting edge between the flank face and rake face. The cutting tool includes micro-nozzles formed in at least one of the tool body and the insert, and aimed at the cutting edge. Each micro-nozzle generates a micro jet of cutting fluid in close proximity to the cutting edge and adjacent to at least one of the flank face and the rake face.