Digital Commons Network^™

Diffusion Of Fission Products In Nuclear Graphite, Kevin Graydon

Electronic Theses and Dissertations, 2020-2023

The next generation of nuclear reactors (Generation IV) are specified to use graphite as the choice material for neutron moderation and structural components. For this reason, study of diffusion behavior of the fission product, ruthenium (Ru), in the candidate graphite grades, POCO AXF-5Q & ZXF-5Q, IG-110, NBG-18 and PCEA, is necessary. Diffusion data for Ru in these grades is absent due to the lack of prior studies and this work aims to fill this void and begin the study of this metallic fission product's diffusion behavior. By utilizing physical vapor deposition (PVD), dynamic secondary ion mass spectroscopy (SIMS), and the …

Total Synthesis Of Natural Products From Oxidative Dearomatization, Nameer Ezzat

Electronic Theses and Dissertations, 2020-2023

The goal of our research is to prepare natural products and related core structures through oxidative dearomatization. The development of a stereoselective iron (III)-mediated intramolecular cascade dearomatization of phenol allowed access to various spirocyclohexadienones and tropons in one step using potassium ferricyanide via single electron transfer (SET). Using this oxidative dearomatization reaction, the thesis focuses on three main parts. The first part is the synthetic efforts toward total synthesis of Harringtonolide. The second part focused on the synthesis of spiro[4.5]decane, a core structure in multiple natural products. The spiro compounds were prepared from ortho hydroxyphenyl nitroalkanes using SET reaction with …

Reconstruction Of Bacterial Strain Genomes From Shotgun Metagenomic Reads, Xin Li

Electronic Theses and Dissertations, 2020-2023

It is necessary to study bacterial strains in environmental samples. The environmental samples are mixed DNA samples collected from the ocean, soil, lake, human body sites, etc. In a natural environment, they provide us new insights into the diversity of our earth. As for bacterial strains on or inside human bodies, to select the proper treatment for diseases caused by bacterial strains, it is critical to identify the corresponding strains and reconstruct their genomes. However, it is a challenge to do so with the DNA from a large number of unknown microbial species mixed together in an environmental sample. The …

Deep Recurrent Networks For Gesture Recognition And Synthesis, Mehran Maghoumi

Electronic Theses and Dissertations, 2020-2023

It is hard to overstate the importance of gesture-based interfaces in many applications nowadays. The adoption of such interfaces stems from the opportunities they create for incorporating natural and fluid user interactions. This highlights the importance of having gesture recognizers that are not only accurate but also easy to adopt. The ever-growing popularity of machine learning has prompted many application developers to integrate automatic methods of recognition into their products. On the one hand, deep learning often tops the list of the most powerful and robust recognizers. These methods have been consistently shown to outperform all other machine learning methods …

Theoretical Analysis Of The Conduction Properties Of Self Assembled Molecular Tunnel Junctions, Cameron Nickle

Electronic Theses and Dissertations, 2020-2023

As the size scale of electrical devices approach the atomic scale. Moore's law is predicted to be over for semiconductor devices. Studies into the replacement of semiconductor technology with organic devices was first predicted by Avriam and Ratner[1] in 1974. Since then significant research into molecular based organic devices has been conducted. The work presented in this dissertation explores the theoretical frameworks used to model transport through molecular junctions. We present studies which seek to garner a better understanding of the charge transport through molecular junctions and how the conduction properties can be optimized. We show that a single atom …

Cell Encapsulation In Microfluidic Channels, Mohammad Nooranidoost

Electronic Theses and Dissertations, 2020-2023

Droplet Microfluidics can be utilized to control the production of single droplets and double emulsions in biomedical application. This dissertation analyzes the droplet formation in hydrophobic and hydrophilic microchannels, encapsulation of cells in flow-focusing channels, and deformation of cell-laden droplets in constricted microcapillaries. The formation of droplets is studied in hydrophobic and hydrophilic channels in order to investigate the role of contact angle on flow structures and droplet generation patterns. In the hydrophobic case, stable and well-structured droplet and slug generation is achieved. However, the flow structure in the hydrophilic case significantly depends on contact angles of the walls. A …

Bias And Sensitivity Of Nonlinear Models For Seismic Response Of Ordinary Standard Bridges, Andres Rodriguez Caballero

Electronic Theses and Dissertations, 2020-2023

The implementation of nonlinear structural analysis under large deformation demands has enabled more realistic response prediction in comparison with the classical linear approaches. However, the sensitivity to modeling assumptions, element and material formulations, implementations, and parameter selection may lead to unreliable results. While previous works have led to a better understanding of how to best model nonlinear static responses of bridge components and systems, the introduction of dynamic loads and the corresponding material hysteresis presents an additional source of variability in the nonlinear responses. The current research involves the analysis of two ordinary standard bridges in California under seismic load …

Analyzing User Behavior In Collaborative Environments, Samaneh Saadat

Electronic Theses and Dissertations, 2020-2023

Discrete sequences are the building blocks for many real-world problems in domains including genomics, e-commerce, and social sciences. While there are machine learning methods to classify and cluster sequences, they fail to explain what makes groups of sequences distinguishable. Although in some cases having a black box model is sufficient, there is a need for increased explainability in research areas focused on human behaviors. For example, psychologists are less interested in having a model that predicts human behavior with high accuracy and more concerned with identifying differences between actions that lead to divergent human behavior. This dissertation presents techniques for …

3d Printing Technology On Spare Parts Business Supply Chain Management: A Case Study In Appliance Industry, Salih Boysan

Dissertations and Theses @ UNI

This study investigates the effects of using Additive Manufacturing (AM), also known as 3D printing, to produce spare parts within the supply chain of an appliance manufacturing company.

This research is based on an analysis of the operation of a spare parts business of an appliance manufacturing company. This research study used real data to investigate the feasibility of using 3D printing to reduce complexity in the spare parts division in terms of supplier rationalization, inventory reduction, and total cost of ownership. The research method used two scenarios: one where manufacturing spare parts traditionally was the baseline model and the …

Audre Lorde & The Ontology Of Desire, Lauren Koenig

Scripps Senior Theses

This thesis advances an understanding of the ontological impact of Western conceptions of sexuality guided by a model of reparative reading as outlined by Eve Kosofosky Sedgwick. Rather than multiply and magnify anti-patriarchal invective, I use deconstructive techniques as a means of analyzing selections from the poetry of Audre Lorde (including “Bloodbirth,” “Making it,” “Pirouette,” and “Therapy”) in order to explore how a consideration of lesbian sexuality can inform an understanding of the more widespread conflation between writing, creation, and birth of the self.

The investigation centers on a variety of paradoxes encountered in the felt sense-oriented language of desire …

Childhood Obesity In California: The Impact Of School Lunch Options And Physical Education Standards In Public Elementary Schools, Audrey Connell

Scripps Senior Theses

Obesity is a biosocial phenomenon in that it is shaped by both biological and social processes. On the biological level, excess body fat increases one’s risk of placing the body in a non-homeostatic state that can weaken the immune response. On the social level, social inequalities are linked to obesity in the United States where racial and ethnic minority communities with low education and high poverty rates bear the largest burden of obesity. In various institutions, multiple actors such as food marketers, public health officials, policy makers, and school administrators dictate the opportunities available to children for them to reach …

Csm 3770, Clas

Executive Actions

No abstract provided.

Mat 3400, Clas

Executive Actions

No abstract provided.

Mat Prereqs, Clas

Executive Actions

No abstract provided.

Nur 2613, Chhs

Executive Actions

No abstract provided.

Distance Oracles For Interval Graphs Via Breadth-First Rank/Select In Succinct Trees, Meng He, J. Ian Munro, Yakov Nekrich, Sebastian Wild, Kaiyu Wu

Michigan Tech Publications, Part 1

We present the first succinct distance oracles for (unweighted) interval graphs and related classes of graphs, using a novel succinct data structure for ordinal trees that supports the mapping between preorder (i.e., depth-first) ranks and level-order (breadth-first) ranks of nodes in constant time. Our distance oracles for interval graphs also support navigation queries – testing adjacency, computing node degrees, neighborhoods, and shortest paths – all in optimal time. Our technique also yields optimal distance oracles for proper interval graphs (unit-interval graphs) and circular-arc graphs. Our tree data structure supports all operations provided by different approaches in previous work, as well …

Digital Storytelling As An Astronomy Disciplinary Literacy Enhancement Approach For Adolescent Kyrgyzstani Efl Students, Nadezhda Chubko

Theses: Doctorates and Masters

This research explored the impact of a digital storytelling (DST) video-making intervention in an astronomy course (STEM-A) on EFL students’ STEM-A disciplinary literacy acquisition in English. The research was motivated by the increased significance of English as an international language of STEM instruction and addressed the transition between discourses encountered by students learning STEM in a foreign language.

The study was designed and implemented as a mixed methods four-cycle action research with multiple Case Study, multiple-probe quasi-experimental design. In the first cycle, the researcher transitioned from a teacher of English to speakers of other languages (TESOL) to a teacher of …

Effect Of O2 Concentration In Ambient Mixture And Multiphase Radiation On Pollutant Formation In Ecn Spray-A, Khaled Mosharraf Mosharraf Mukut, Somesh Roy

Mechanical Engineering Faculty Research and Publications

The present study investigates the formation and evolution of soot and NO_X in a high-pressure constant-volume combustion chamber. This work focuses on the effect of multiphase thermal radiation and O₂ dilution in ambient/exhaust gases, some- times also referred to as exhaust gas recirculation(EGR), qualitatively and quantitatively. The spray-A case (n-dodecane as fuel) from Engine Combustion Network (ECN) is used as the target condition. Two different soot modeling approaches have been considered: a semi-empirical two-equation model and a detailed method of moments with interpolative closure (MOMIC) model. A multiphase photon Monte Carlo (PMC) solver with line-by-line (LBL) spectral data …

A Novel Data-Driven Scheme For The Ship Wake Identification On The 2-D Dynamic Sea Surface, Yanming Zhang, Lijun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

Because the ship wake spreads into an area much larger than that of the ship hull in the sea surface, it has been widely used in the ship detection. However, due to the complex sea wave motion and the high sea state, the ship wake detection is still a challenging task. In this paper, we propose a novel data-driven method based on dynamic mode decomposition (DMD) to detect, reconstruct, and locate the Kelvin wake on the two-dimensional dynamic sea surface. Through the proposed method, the sea's dynamic characteristics including the oscillation frequency and decay/growth rate of ship wakes and the …

Impartial Sensor Tasking Via Forecasted Information Content Quantification, Matthew J. Gualdoni, Kyle J. Demars

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The consistently increasing population of space debris in orbit about the Earth is becoming an increasingly unavoidable problem, necessitating a proper handling of the problem of sensor tasking to effectively and efficiently obtain observations of space objects to maintain catalogs of their positions and velocities. A variety of approaches have been explored to achieve this in an autonomous fashion, assisting with space traffic management. This work presents new statistical analysis of the Kullback–Leibler divergence justifying the use of its expected value in generating sensor schedules. This divergence's use as an objective measure is extended to simultaneously consider, in an impartial …

Optimization Strategies For Myopic And Forecasted Divergence-Based Sensor Tasking Objectives, Matthew J. Gualdoni, Kyle J. Demars

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In light of the ever-increasing value of space assets operating in the presence of a continuously growing population of space objects in orbit about Earth, space situational awareness is becoming more crucial than ever. The process of tracking and maintaining estimates for the numerous assets and space objects is a complex and highly demanding problem, as it requires robust state estimates in the presence of sparse data. As the number of space objects greatly outweighs the number of available sensors, a sensor tasking policy is necessary to properly utilize the available sensor resources in a way that ensures targets are …

Robustness Metric For Robust Design Optimization Under Time-And Space-Dependent Uncertainty Through Metamodeling, Xinpeng Wei, Xiaoping Du

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Product performance varies with respect to time and space in many engineering applications. This paper discusses how to measure and evaluate the robustness of a product or component when its quality characteristics (QCs) are functions of random variables, random fields, temporal variables, and spatial variables. At first, the existing time-dependent robustness metric is extended to the present time-and space-dependent problem. The robustness metric is derived using the extreme value of the quality characteristics with respect to temporal and spatial variables for the nominal-the-better type quality characteristics. Then, a metamodel-based numerical procedure is developed to evaluate the new robustness metric. The …

Thermodynamic Properties Of Hydroxylammonium Nitrate-Based Electric Solid Propellant Plasma, Matthew S. Glascock, Patrick D. Drew, Joshua L. Rovey, Kurt A. Polzin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Electric solid propellants are advanced solid chemical rocket propellants controlled by electric current. An electric solid propellant may also be used in an electric propulsion system: specifically, an ablative pulsed plasma thruster. Previous experiments with the electric solid propellant known as high-performance electric propellant, or HIPEP, suggest its ablation processes are similar to the traditional propellant polytetrafluoroethylene (C2 F4). Better understanding of the ablation and the resulting propulsion performance of HIPEP requires a model of its vapor composition, bulk plasma quantities, and thermodynamic properties. Such a model was developed and favorably compared with previous analogous model predictions found in the …

Applications Of Polynomial Chaos-Based Cokriging To Aerodynamic Design Optimization Benchmark Problems, Jethro Nagawkar, Leifur Leifsson, Xiaosong Du

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this work, the polynomial chaos-based Cokriging (PC-Cokriging) is applied to a benchmark aerodynamic design optimization problem. The aim is to perform fast design optimization using this multifidelity metamodel. Multifidelity metamodels use information at multiple levels of fidelity to make accurate and fast predictions. Higher amount of lower fidelity data can provide important information on the trends to a limited amount of high-fidelity (HF) data. The PC-Cokriging metamodel is a multivariate version of the polynomial chaos-based Kriging (PC-Kriging) metamodel and its construction is similar to Cokriging. It combines the advantages of the interpolation-based Kriging metamodel and the regression-based polynomial chaos …

Numerical Study Of Paramagnetic Elliptical Microparticles In Curved Channels And Uniform Magnetic Fields, Christopher Sobecki, Jie Zhang, Cheng Wang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We numerically investigated the dynamics of a paramagnetic elliptical particle immersed in a low Reynolds number Poiseuille flow in a curved channel and under a uniform magnetic field by direct numerical simulation. A finite element method, based on an arbitrary Lagrangian-Eulerian approach, analyzed how the channel geometry, the strength and direction of the magnetic field, and the particle shape affected the rotation and radial migration of the particle. The net radial migration of the particle was analyzed after executing a π rotation and at the exit of the curved channel with and without a magnetic field. In the absence of …

Off-Policy Q-Learning For Anti-Interference Control Of Multi-Player Systems, Jinna Li, Zhenfei Xiao, Tianyou Chai, Frank L. Lewis, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

This paper develops a novel off-policy game Q-learning algorithm to solve the anti-interference control problem for discrete-time linear multi-player systems using only data without requiring system matrices to be known. The primary contribution of this paper lies in that the Q-learning strategy employed in the proposed algorithm is implemented in an off-policy policy iteration approach other than on-policy learning due to the well-known advantages of off-policy Q-learning over on-policy Q-learning. All of the players work hard together for the goal of minimizing their common performance index meanwhile defeating the disturbance that tries to maximize the specific performance index, and finally …

The Distributional Short-Term Impact Of The Covid-19 Crisis On Wages In The United States, Yonatan Berman

Publications and Research

This paper uses Bureau of Labor Statistics employment and wage data to study the distributional impact of the COVID-19 crisis on wages in the United States by mid-April. It answers whether wages of lower-wage workers decreased more than others', and to what extent. We find that the COVID-19 outbreak exacerbates existing inequalities. Workers at the bottom quintile in mid-March were three times more likely to be laid off by mid-April compared to higher-wage workers. Weekly wages of workers at the bottom quintile decreased by 6% on average between mid-February and mid-March and by 26% between mid-March and mid-April. The average …

Singlet Fission In A Hexacene Dimer: Energetics Dictate Dynamics, Samuel N. Sanders, Elango Kumarasamy, Kealan J. Fallon, Matthew Y. Sfeir, Luis M. Campos

Publications and Research

Singlet fission (SF) is an exciton multiplication process with the potential to raise the efficiency limit of single junction solar cells from 33% to up to 45%. Most chromophores generally undergo SF as solid-state crystals. However, when such molecules are covalently coupled, the dimers can be used as model systems to study fundamental photophysical dynamics where a singlet exciton splits into two triplet excitons within individual molecules. Here we report the synthesis and photophysical characterization of singlet fission of a hexacene dimer. Comparing the hexacene dimer to analogous tetracene and pentacene dimers reveals that excess exoergicity slows down singlet fission, …

Double Inclusive Small-X Gluon Production And Their Azimuthal Correlations In A Biased Ensemble, Gary Kapilevich

Publications and Research

We consider double gg → g production in the presence of a bias on the unintegrated gluon distribution of the colliding hadrons or nuclei. Such bias could be due to the selection of configurations with a greater number of gluons or higher mean transverse momentum squared or, more generally, due to a modified spectral shape of the gluon distribution in the hadrons. Hence, we consider reweighted functional averages over the stochastic ensemble of small-x gluons. We evaluate explicitly the double inclusive gluon transverse momentum spectrum in high-energy collisions, and their azimuthal correlations, for a few simple examples of biases.

On The Classification Of Duality Webs For Graded Quivers, Sebastían Franco, Azeem Hasan, Xingyang Yu

Publications and Research

We study the m-graded quiver theories associated to CY (m+2)-folds and their order (m + 1) dualities. We investigate how monodromies give rise to mutation invariants, which in turn can be formulated as Diophantine equations characterizing the space of dual theories associated to a given geometry. We discuss these ideas in general and illustrate them in the case of orbifold theories. Interestingly, we observe that even in this simple context the corresponding Diophantine equations may admit an infinite number of seeds for m ≥ 2, which translates into an infinite number of disconnected duality webs. Finally, …