Engineering Commons^™

Propane Dehydrogenation On Single Site Gallium On Silica Catalyst, Shankali U. Pradhan

Open Access Theses

Light alkane dehydrogenation is gaining increasing importance due to the discovery of shale gas. Gallium based catalysts such as Ga/HZSM-3 and Ga₂O₃ have been used to dehydrogenate propane to propylene. However, the exact nature of the active site for propane dehydrogenation on Gallium based catalysts is still debated in literature. This work is aimed at understanding the nature of active site in Ga/SiO₂ catalyst for propane dehydrogenation. The Ga/SiO₂ catalyst is active and selective for propane dehydrogenation reaction. It is shown that Ga ⁺³ site co-ordinated with four O atoms is the most active form …

Calculus For Decision Systems, Jorge Antonio Samayoa Ranero

Open Access Dissertations

The conceptualization of the term "system" has become highly dependent on the application domain. What a physicist means by the term system might be different than what a sociologist means by the same term. In 1956, Bertalanffy [1] defined a system as " a set of units with relationships among them". This and many other definitions of system share the idea of a system as a black box that has parts or elements interacting between each other. This means that at some level of abstraction all systems are similar, what eventually differentiates one system from another is the set of …

Genome-Wide Profiling Of Histone Modifications (H3k9me2 And H4k12ac) And Gene Expression In Rust (Uromyces Appendiculatus) Inoculated Common Bean (Phaseolus Vulgaris L), Vasudevan Ayyappan, Venu Kalavacharla, Jyothi Thimmapuram, Ketaki P. Bhide, Venkateswara R. Sripathi

Cyber Center Publications

Histone modifications such as methylation and acetylation play a significant role in controlling gene expression in unstressed and stressed plants. Genome-wide analysis of such stress-responsive modifications and genes in non-model crops is limited. We report the genome-wide profiling of histone methylation (H3K9me2) and acetylation (H4K12ac) in common bean (Phaseolus vulgaris L.) under rust (Uromyces appendiculatus) stress using two high-throughput approaches, chromatin immunoprecipitation sequencing (ChIP-Seq) and RNA sequencing (RNA-Seq). ChIP-Seq analysis revealed 1,235 and 556 histone methylation and acetylation responsive genes from common bean leaves treated with the rust pathogen at 0, 12 and 84 hour-after-inoculation (hai), while …

Nanohub.Org: A Gateway To Undergraduate Simulation-Based Research In Materials Science And Related Fields, Tanya A. Faltens, Peter A. Bermel, Amanda Buckles, K Anna Douglas, Alejandro H. Strachan, Lynn K. Zentner, Gerhard Klimeck

Birck and NCN Publications

Our future engineers and scientists will likely be required to use advanced simulations to solve many of tomorrow's challenges in nanotechnology. To prepare students to meet this need, the Network for Computational Nanotechnology (NCN) provides simulation-focused research experiences for undergraduates at an early point in their educational path, to increase the likelihood that they will ultimately complete a doctoral program. The NCN summer research program currently serves over 20 undergraduate students per year who are recruited nationwide, and selected by NCN and the faculty for aptitude in their chosen field within STEM, as well as complementary skills such as coding …

A Physics-Based Compact Model For Thermoelectric Devices, Kyle Jeffrey Conrad

Open Access Theses

Thermoelectric devices have a wide variety of potential applications including as coolers, temperature regulators, power generators, and energy harvesters. During the past decade or so, new thermoelectric materials have been an active area of research. As a result, several new high figure of merit (zT) materials have been identified, but practical devices using these new materials have not yet been reported. A physics-based compact model could be used to simulate a thermoelectric devices within a full system using SPICE-compatible circuit simulators. If such a model accepts measured or simulated material parameters, it would be useful in exploring the …

Assessing Coupled Mechanical Behavior And Environmental Degradation At Submicron Scales, Samantha K Lawrence

Open Access Dissertations

Mechanical and electromechanical properties, deformation and fracture mechanisms, and environmental resistance of materials at submicron scales have been investigated through the combination of nanomechanical testing, high resolution microscopy, diffraction, and electrochemical testing. Nanomechanical techniques were used to isolate environmental, orientation, and size effects. Material evaluation focuses on metals, both model and engineering alloys, in bulk and thin-film form as well as oxide-substrate systems. Yield behavior of Ni 200, a model material, depends on sampled volume size, orientation, and surface preparation. Exposure to high-pressure hydrogen gas is also found to impact incipient plasticity and mechanical properties of commercially pure Ni 201. …

Instrumentation And Development Of A Mass Spectrometry System For The Study Of Gas-Phase Biomolecular Ion Reactions, Ziqing Lin

Open Access Dissertations

Gas-phase reactions of biomolecular ions are highly relevant to the understanding of structures and functions of the biomolecules. Mass spectrometry is a powerful tool in investigating gas-phase ion chemistry. Various mass spectrometers have been developed to explore ion/molecule reactions, ion/ion reactions, ion/photon reactions, ion/radical reactions etc., both at atmospheric pressure and in vacuum. In-vacuum reactions have an advantage of involving pre-selecting the ions for the reactions using a mass analyzer. Over the decades, a variety of mass analyzers have been employed in the research of ion chemistry. Hybrid configurations, such as quadrupole ion trap with a time-of-flight and or a …

Modeling, Optimization, And Sensitivity Analysis Of A Continuous Multi-Segment Crystallizer For Production Of Active Pharmaceutical Ingredients, Bradley James Ridder

Open Access Dissertations

We have investigated the simulation-based, steady-state optimization of a new type of crystallizer for the production of pharmaceuticals. The multi-segment, multi-addition plug-flow crystallizer (MSMA-PFC) offers better control over supersaturation in one dimension compared to a batch or stirred-tank crystallizer. Through use of a population balance framework, we have written the governing model equations of population balance and mass balance on the crystallizer segments. The solution of these equations was accomplished through either the method of moments or the finite volume method. The goal was to optimize the performance of the crystallizer with respect to certain quantities, such as maximizing the …

Structure-Activity Relationships For The Water-Gas Shift Reaction Over Supported Metal Catalysts, Kaiwalya D. Sabnis

Open Access Dissertations

The Water-Gas Shift (WGS) reaction (CO + H₂O → CO₂ + H₂) is an important chemical process for industrial hydrogen production. The overall goal of this project is to use kinetic experiments and in situ characterization techniques in tandem, in order to derive structure-activity relationships for various catalytic systems. These relationships facilitate the rational catalyst design by identification of catalyst descriptors. In order to establish such relationships, various studies were undertaken, such as (i) effect of transition admetals on the WGS catalysis by molybdenum carbide (ii) effect of residual oxygen content on the performance of …

Novel Techniques For Quasi Three-Dimensional Nanofabrication Of Transformation Optics Devices, Paul R. West

Open Access Dissertations

Current nanofabrication is almost exclusively limited to top-down, two-dimensional techniques. As technology moves more deeply into the nano-scale regime, fabrication of new devices with quasi three-dimensional geometries shows great potential. One excellent example of an emerging field that requires this type of non-conformal 3D fabrication technique is the field of Transformation Optics. This field involves transforming and manipulating the optical space through which light propagates. Arbitrarily manipulating the optical space requires advanced fabrication techniques, which are not possible with current two-dimensional fabrication technologies. One step toward quasi three-dimensional nanofabrication involves employing angled deposition allowing new growth mechanisms, and enabling a …

Kesterite Thin-Film Solar Cell Absorbers Derived Using Inhomogeneous Czts Nanoparticles, Wei-Chang D. Yang

Open Access Dissertations

My doctoral research focuses on understanding the structure-property-processing relationship of the kesterite materials to improve their device performance. It is recognized in both my own work and the recent literature that the structural and compositional integrities of CZTSSe are crucial to derive the solar cell grade kesterite thin-films. Analytical electron microscopy (AEM) allows me to demonstrate the structural and compositional inhomogeneity of the CZTS nanoparticles and CZTSSe thin-films at the nanoscale. For example, the observed forbidden reflections in TED patterns and FFT diffractograms corresponding to HRTEM images indicate that cation disorder leads to stacking faults in CZTS nanoparticles. Probe-corrected STEM …

Characterization And Mechanical Properties Of Solar Grade Silicon In Granular And Nanopowder Form, Mohamad Bilal Zbib

Open Access Dissertations

Polycrystalline silicon is mainly used for solar cell applications, structures in micro-electromechanical systems, and production of single crystal Si. One of the relatively new methods for producing large quantities of polysilicon is fluidized bed reactor (FBR), where two main morphologies are produced, granular solid (1-3 mm) and nanopowders (30-300 nm). Grinding and fracture occurs in the granular solid during shipping and handling which can affect the final product properties and create safety issues. The microstructure and the morphology of both the granular and the nanopowder forms of Si were examined using scanning and transmission electron microscopes (SEM and TEM). The …

Structure-Thermal Coupling In Viscoelastic Material In Rubber Bushing Of Vehicle System, Zhengui Zhang

Open Access Dissertations

The objective of this research is to utilize the frequency-dependent viscoelastic material model and characterize the dynamic response of rubber bushing under external excitation. Furthermore, with appropriate modeling, two heat generation mechanisms of rubber bushing are explored and their thermal fields are investigated. Due to the nonlinear force-deflection relationship of the viscoelastic material, finding satisfactory mechanical properties of rubber components still poses a great challenge. However, industry nowadays is in urgent demand for precise finite element analysis (FEA) modeling of rubber components. For example, a proper constitutive relationship of rubber components is critical to providing a reliable and trustable simulation …

Behavior Of Reinforced Concrete Panels Subject To Impact By Non-Deformable Projectiles, Amer Abdel Karim Alkloub

Open Access Dissertations

In impact resistance of reinforced concrete (RC) panels against projectiles the contribution of the orthogonal mesh reinforcement has been ignored. In this study the contribution of mesh reinforcement to impact resistance and itseffect on the nature of local damage caused by impact of non-deformable projectiles are investigated. The investigation included a combination of 53 experiments and series of finite-element based numerical simulations. Three levels of local damage modes were investegated based on the severity of the degree of damage in the impacted panels. Mesh reinforcement ratio within the range of reinforcement ratio considered, namely 0.19% to 0.48%, was irrelevant to …

Laser Scanner Jitter Characterization, Page Content Analysis For Optimal Rendering, And Understanding Image Graininess, Yi-Ting Chen

Open Access Dissertations

In Chapter 1, the electrophotographic (EP) process is widely used in imaging systems such as laser printers and office copiers. In the EP process, laser scanner jitter is a common artifact that mainly appears along the scan direction due to the condition of polygon facets. Prior studies have not focused on the periodic characteristic of laser scanner jitter in terms of the modeling and analysis. This chapter addresses the periodic characteristic of laser scanner jitter in the mathematical model. In the Fourier domain, we derive an analytic expression for laser scanner jitter in general, and extend the expression assuming a …

Advanced Wireless Communications Using Large Numbers Of Transmit Antennas And Receive Nodes, Junil Choi

Open Access Dissertations

The concept of deploying a large number of antennas at the base station, often called massive multiple-input multiple-output (MIMO), has drawn considerable interest because of its potential ability to revolutionize current wireless communication systems. Most literature on massive MIMO systems assumes time division duplexing (TDD), although frequency division duplexing (FDD) dominates current cellular systems. Due to the large number of transmit antennas at the base station, currently standardized approaches would require a large percentage of the precious downlink and uplink resources in FDD massive MIMO be used for training signal transmissions and channel state information (CSI) feedback. First, we propose …

Overweight Vehicle Permitting Alternatives, Stephanie R Everett

Open Access Dissertations

Overweight vehicles exceed the federal and/or state statutory limits for either the gross vehicle weight (GVW) or the weight of individual axles or axle groups. National and state limits on vehicle weights were established to preserve the highway infrastructure. Past research has shown that overweight operations, while causing significant damage to roads and bridges, can enhance the trucking industry productivity, and thus yield economic benefits both regionally and nationally. In the United States, individual states administer oversize and overweight vehicle permit programs to regulate and collect revenues from overweight operations. Differences in the truck size and weight limits and overweight …

First In The Family: A Comparison Of First-Generation And Non-First-Generation Engineering College Students, Dina Verdin, Allison F. Godwin

School of Engineering Education Graduate Student Series

This study investigates first-generation and non-first-generation engineering undergraduates’ math/science identities, subject-related interests, and career plans. First-generation students are an understudied, but growing population. Understanding how these self-beliefs and background factors affect students’ engineering choice can help widen pathways into engineering which continues to be defined as “pale and male.” Additionally, identity has predictive value for practical outcomes like engineering choice in college. The data for this study comes from the nationally representative Sustainability and Gender in Engineering (SaGE) survey completed by 6,772 college students who enrolled in first-year English courses at 2- and 4-year colleges across the U.S. …

An Engineering Tale: Using Storybooks To Analyze Parent–Child Conversations About Engineering (Fundamental), Brianna L. Dorie, Monica Cardella

School of Engineering Education Graduate Student Series

Envisioning a larger workforce of engineers, with broad participation from a diverse set of workers, is one of the central concerns of engineering education research. While many current K-12 programs focus on engineering thinking and design, there is still a need to promote aspiration and understanding of engineering as an occupation, especially in out-of-school environments where children spend a majority of their time. Career aspirations and expectations of children have already started to develop prior to entering formal schooling. Several studies has shown that parents play a significant role in the development of occupational awareness in their children, but the …

Qualitative Study Of First-Generation Latinas: Understanding Motivation For Choosing And Persisting In Engineering, Dina Verdin, Allison F. Godwin, Jennifer Morazes

School of Engineering Education Graduate Student Series

Latina undergraduates pursuing an engineering degree continue to be an underrepresented group at four-year universities. Compared to their male counterparts, fewer women enter the field of engineering; however, of those Latino/as who do matriculate, they have the same likelihood of persisting as their White counterparts. Furthermore, a dearth of underrepresented students such as Latino/as and first-generation college students enter or remain in the field of engineering. The need for increased gender and racial/ethnic representation in engineering is a documented need allowing for the production of a wider range of innovative products that take into consideration different perspectives that represent the …

Roundabout Maintenance Flipbook, Indiana Ltap

Indiana Local Technical Assistance Program (LTAP) Publications

This flipbook is a summary of the work pub­lished in the Roundabout Maintenance Manual by Indiana LTAP. This information was collected through a series of interviews with city engi­neers, public works directors, and street commis­sioners experienced in roundabout maintenance. It serves as a model to guide work crews in correct maintenance procedures.

Roundabout Maintenance Manual, Indiana Ltap

Indiana Local Technical Assistance Program (LTAP) Publications

This maintenance manual serves as an additional resource for communities who have imple­mented roundabouts or are considering them. There are a few other published guides, such as the NCHRP Report 672, Roundabouts: An Informational Guide, and the Wisconsin DOT Facilities Develop­ment Manual. However, the information covered in these guides is very broad. This manual provides specific information regarding roundabout maintenance.

Engineering Together: Context In Dyadic Talk During An Engineering Task (K-12 Fundamental), Brianna L. Dorie, Monica Cardella, Gina Navoa Svarovsky

School of Engineering Education Graduate Student Series

Exploring how children develop early interest and understanding in engineering canprovide useful information for the ongoing efforts to increase the access of women inengineering careers. Drawing on occupational choice theories, girls and women havetended to place a high value on helping others in their work, but do not often realize thatcareers in engineering can lead to these types of endeavors. Adding layers of socialcontext that highlight the connections between engineering endeavors and improving thelives of others may create a more engaging experience for girls and women, andpotentially lead to increased development of girls’ engineering interest and understanding.Additionally, informal learning environments …

Special Session: Building Intentional Community Partnerships, Julia D. Thompson, Juan C. Lucena, Marybeth Lima, Brent Jesiek

School of Engineering Education Graduate Student Series

Recent growth in community engagement programs in engineering education clearly reveals the importance of understanding partnerships between the engagement programs and the community they work with. However, there has been minimal research and reflection on engineering education partnerships. In this special session, the participants will learn about theoretical frameworks that categorize different types of interactions within partnerships and practical implications on how to structure programs that make the community an integral part of the community engagement experience. The special session will be highly interactive, and will be grounded in the Transactional, Cooperative, and Communal (TCC) Framework that categorizes interactions within …

Development Of Entrepreneurial Attitudes Assessment Instrument For Freshman Students, Todd M. Fernandez, Genisson Sliva Coutinho, Michael D. Wilson, Stephen R. Hoffmann

School of Engineering Education Graduate Student Series

An increasing population of university programs and quantity of curricular content focused on entrepreneurship poses both enormous opportunities for student growth, and numerous practical challenges. Prior work has largely focused on pre-post assessment of student learning, shifts in‘mindset’, activity effectiveness, mapping of student outcomes, and implications of student learning on career success. A baseline of freshman student attitudes towards entrepreneurship,outside of specifically focused entrepreneurial leaning, has significant potential to identify and inform programming in entrepreneurship, as well as general curriculums and pedagogy. An improved understanding of student’s constructive and cognitive influences in entrepreneurial education will serve to better inform the …

Optimizing Strategies For Population-Based Chlamydia Infection Screening Among Young Women: An Age-Structured System Dynamics Approach Infectious Disease Epidemiology, Yu Teng, Nan Kong, Wanzhu Tu

Weldon School of Biomedical Engineering Faculty Publications

Background

Chlamydia infection (CT) is one of the most commonly reported sexually transmitted diseases. It is often referred to as a “silent” disease with the majority of infected people having no symptoms. Without early detection, it can progress to serious reproductive and other health problems. Economical identification of asymptomatically infected is a key public health challenge. Increasing evidence suggests that CT infection risk varies over the range of adolescence. Hence, age-dependent screening strategies with more frequent testing for certain age groups of higher risk may be cost-saving in controlling the disease.

Methods

We study the optimization of age-dependent screening strategies …

Bifacial Si Heterojunction-Perovskite Organic-Inorganic Tandem To Produce Highly Efficient (Η T * ~ 33%) Solar Cell, Reza Asadpour, Raghu Vamsi Krishna Chavali, Mohammad Ryyan Khan, Muhammad Ashraful Alam

Department of Electrical and Computer Engineering Faculty Publications

As single junction photovoltaic (PV) technologies both Si heterojunction (HIT) and perovskite based solar cells promise high efficiencies at low cost. Intuitively a traditional tandem cell design with these cells connected in series is expected to improve the efficiency further. Using a self-consistent numerical modeling of optical and transport characteristics however we find that a traditional series connected tandem design suffers from low JSC due to band-gap mismatch and current matching constraints. Specifically a traditional tandem cell with state-of-the-art HIT ( η=24% ) and perovskite ( η=20% ) sub-cells provides only a modest tandem efficiency of η_T~ 25%. …

A Simple Boltzmann Transport Equation For Ballistic To Diffusive Transient Heat Transport, Mark S. Lundstrom, Jesse Maassen

Department of Electrical and Computer Engineering Faculty Publications

Developing simplified, but accurate, theoretical approaches to treat heat transport on all length and time scales is needed to further enable scientific insight and technology innovation. Using a simplified form of the Boltzmann transport equation (BTE), originally developed for electron transport, we demonstrate how ballistic phonon effects and finite-velocity propagation are easily and naturally captured. We show how this approach compares well to the phonon BTE, and readily handles a full phonon dispersion and energy-dependent mean-free-path. This study of transient heat transport shows (i) how fundamental temperature jumps at the contacts depend simply on the ballistic thermal resistance, (ii) that …

Steady-State Heat Transport: Ballistic-To-Diffusive With Fourier's Law, Jesse Maassen, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

It is generally understood that Fourier's law does not describe ballistic phonon transport, which is important when the length of a material is similar to the phonon mean-free-path. Using an approach adapted from electron transport, we demonstrate that Fourier's law and the heat equation do capture ballistic effects, including temperature jumps at ideal contacts, and are thus applicable on all length scales. Local thermal equilibrium is not assumed, because allowing the phonon distribution to be out-of-equilibrium is important for ballistic and quasi-ballistic transport. The key to including the non-equilibrium nature of the phonon population is to apply the proper boundary …

Computational Electronics For The 21st Century: Reflections On The Past, Present, And Future, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

The author’s career has coincided with the development of numerical simulation into an essential component of semiconductor device technology research and development. We now have a sophisticated suite of simulation capabilities along with new challenges for 21st Century electronics. This talk presents a short history of the field and a description of the current state of the art, but it concentrates on lessons learned and thoughts about how computational electronics can continue to contribute effectively to the development of new electronic device technologies. The author will argue that electronics is changing, and that computational electronics can play a key role …