Physical Sciences and Mathematics Commons^™

Uv-Light-Tunable P-/N-Type Chemiresistive Gas Sensors Based On Quasi-1d Tis3 Nanoribbons: Detection Of Isopropanol At Ppm Concentrations, Victor V. Sysoev, Andrey V. Lashkov, Alexey Lipatov, Ilya A. Plugin, Michael Bruns, Dirk Fuchs, Alexey S. Varezhnikov, Mustahsin Adib, Martin Sommer, Alexander Sinitskii

Chemistry Department: Faculty Publications

The growing demand of society for gas sensors for energy-efficient environmental sensing stimulates studies of new electronic materials. Here, we investigated quasi-one-dimensional titanium trisulfide (TiS₃) crystals for possible applications in chemiresistors and on-chip multisensor arrays. TiS₃ nanoribbons were placed as a mat over a multielectrode chip to form an array of chemiresistive gas sensors. These sensors were exposed to isopropanol as a model analyte, which was mixed with air at low concentrations of 1–100 ppm that are below the Occupational Safety and Health Administration (OSHA) permissible exposure limit. The tests were performed at room temperature (RT), as …

Formation And Tectonic Evolution Of Structural Slices In Eastern Kargı Massif (Çorum, Türkiye), Cihan Yalçin, Nurullah Hani̇lçi̇, Mustafa Kumral, Mustafa Kaya

Bulletin of the Mineral Research and Exploration

The closure of Tethys Ocean has led to shaping the Central Pontides together with different types of rocks. In the east of Kargı (Gökçedoğan), which is located in the Central Pontides, allochthonous rocks of Late Palaeozoic-Early Cenozoic age and autochthonous units exist together, and allochthonous rocks present various tectono-stratigraphical sequences. Distinctive tectonic slices developed in the area as a consequence of the thrusting of the Permian carbonates from the north towards the south over the Middle Jurassic accretionary Complex (Kunduz Metamorphites) that form the basement of the area, and also because of the thrusting of the units of the Kirazbaşı …

Wildfire Modeling With Data Assimilation, Andrew Johnston

Theses and Dissertations

Wildfire modeling is a complex, computationally costly endeavor, but with droughts worsening and fires burning across the western United States, obtaining accurate wildfire predictions is more important than ever. In this paper, we present a novel approach to wildfire modeling using data assimiliation. We model wildfire spread with a modification of the partial differential equation model described by Mandel et al. in their 2008 paper. Specifically, we replace some constant parameter values with geospatial functions of fuel type. We combine deep learning and remote sensing to obtain real-time data for the model and employ the Nelder-Mead method to recover optimal …

Determining Figure Skating Jump Under-Rotation In Real-Time Using Imu Sensors During Practice, Duncan O. Furgeson

Theses and Dissertations

We explore the use of machine learning to detect under-rotation in figure skating jumps. Under- rotation in jumps is difficult for the skater to sense but learning to recognize under-rotation is an impor- tant part of learning proper jump technique. To address this difficulty, we present the Under-rotation Monitor, or UR Monitor, a system for detecting under-rotated figure skating jumps in real-time. UR Monitor uses a single inertial measurement unit (IMU) attached to the skater's waist that sends a stream of accelerometer and gyroscope data to a mobile phone via Bluetooth. The mobile phone creates and sends an input vector …

Cloud Container Security’ Next Move, Vishakha Sadhwani

Dissertations and Theses

In the last few years, it is apparent to cybersecurity experts everywhere that the proverbial container tech genie is out of the bottle, and has been widely embraced across multiple organizations. To achieve the flexibility of building and deploying applications anywhere and everywhere, cloud native environments have gained great momentum and made the development lifecycle simpler than ever. However, container environments brings with them a range of cybersecurity issues that includes images, containers, hosts, runtimes, registries, and orchestration platforms, which needs the necessity to focus on investing in securing your container stack.

According to this report[1], released by cloud-native …

Uniqueness Of Steady State Positive Solutions To A General Elliptic System With Dirichlet Boundary Conditions, Joon Hyuk Kang

Faculty Publications

The purpose of this paper is to give conditions for the uniqueness of positive solution to a rather general type of elliptic system of the Dirichlet problem on a bounded domain Ω in Rⁿ. Also considered are the effects of perturbations on the coexistence state and uniqueness.

Future Colorado River Basin Drought And Surplus, Rama Bedri, Thomas Piechota

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Historical and future drought and surplus periods in the Colorado River basin are evaluated based on eight climate scenarios. Unimpaired streamflow from 17 stations in the Colorado River are evaluated based on U.S. Geological Survey, Bureau of Reclamation, and Coupled Modeled Intercomparison Projection 5 downscaled data from 1950–2099. Representative Concentration Pathway (RCP) 4.5 and 8.5 emission scenarios are considered for four climate models (HadGEM2-ES, CNRM-CM5, CanESM2, MI-ROC5). Drought (surplus) quantities, magnitudes, severities, and water year flows are compared for the historical and future periods. Results indicate that there is a significant difference between the historical record and future projections. The …

Observation Of The Ξ_B^-→Λ_B^0 Π^- Decay And Measurement Of B(Ξ_B^-→Λ_B^0 Π^-), Zhuoming Li

Dissertations - ALL

We present the first observation of the weak decay Ξ−b → Λ0b π−, which is mediated by an s → u ̄ud transitionwithin the Ξ_b^- baryon. The analysis uses a pp collision data sample at a center-of-mass energy of 13 TeV corresponding to 5.5 fb^(−1) of integrated luminosity. The sample of Λb0 baryons used in this analysis are reconstructed through their decays to Λ+c π− and Λ+c π−π+π−. From a fit to the Ξ−b → Λ0b π− mass spectrum, the Ξ−b → Λ0b π− decay is observed with a significance of 11.3 standard deviations, thus establishing observation of this decay. …

Does Science Need Intersubjectivity? The Problem Of Confirmation In Orthodox Interpretations Of Quantum Mechanics, Emily Adlam

Mathematics, Physics, and Computer Science Faculty Articles and Research

Any successful interpretation of quantum mechanics must explain how our empirical evidence allows us to come to know about quantum mechanics. In this article, we argue that this vital criterion is not met by the class of ‘orthodox interpretations,’ which includes QBism, neo-Copenhagen interpretations, and some versions of relational quantum mechanics. We demonstrate that intersubjectivity fails in radical ways in these approaches, and we explain why intersubjectivity matters for empirical confirmation. We take a detailed look at the way in which belief-updating might work in the kind of universe postulated by an orthodox interpretation, and argue that observers in such …

A Usability Study Of Fido2 Hardware Tokens On Mobile Devices, Stephen Lambert

Theses and Dissertations

Passwords as the primary form of authentication on the web have many issues, such as password re-use across sites and difficulty in remembering secure passwords. The FIDO Alliance has created a passwordless system that has with support from companies like Google, Apple, and Microsoft: FIDO2. Studies have shown so far that users find FIDO2 usable on personal computers, but no work has been published on its usability on mobile devices. I conducted a lab study in which participants used FIDO2 passwordless authentication with hardware tokens on a mobile phone. Participants found FIDO2 usable on mobile devices, but had similar fears …

Computational Studies Of Dinuclear Catalytic Reaction Mechanisms, James Curtis Coombs Iii

Theses and Dissertations

Heterodinuclear and homodinuclear metal complexes with a direct metal-metal interaction offer the potential for unique catalysis due to cooperativity effects that impact reaction mechanisms, reactivity, and selectivity. Quantum-chemical density functional theory (DFT) calculations can directly examine the origin of dinuclear reactivity and selectivity effects. Chapter 1 provides a short overview of heterodinuclear and homodinuclear catalysts that have been experimentally and computationally examined. Chapter 2 reports our study using DFT methods to understand the mechanism and reactivity of a heterodinuclear Co-Zr catalyst with phosphinoamide ligands that catalyzes a Kumada coupling between alkyl halides and alkyl Grignards. Chapter 3 reports DFT calculations …

Algorithmic Improvements In Deep Reinforcement Learning, Norman L. Tasfi

Electronic Thesis and Dissertation Repository

Reinforcement Learning (RL) has seen exponential performance improvements over the past decade, achieving super-human performance across many domains. Deep Reinforcement Learning (DRL), the combination of RL methods with deep neural networks (DNN) as function approximators, has unlocked much of this progress. The path to generalized artificial intelligence (GAI) will depend on deep learning (DL) and RL. However, much work is required before the technology reaches anything resembling GAI. Therefore, this thesis focuses on a subset of areas within RL that require additional research to advance the field, specifically: sample efficiency, planning, and task transfer. The first area, sample efficiency, refers …

An Intercomparison Of Large-Eddy Simulations Of A Convection Cloud Chamber Using Haze-Capable Bin And Lagrangian Cloud Microphysics Schemes, Fan Yang, Fabian Hoffmann, Raymond Shaw, Mikhail Ovchinnikov, Andrew Vogelmann

Michigan Tech Research Data

Recent in-situ observations show that haze particles exist in a convection cloud chamber. The microphysics schemes previously used for large-eddy simulations of the cloud chamber could not fully resolve haze particles and the associated processes, including their activation and deactivation. Specifically, cloud droplet activation is modeled based on Twomey-type parameterizations, wherein cloud droplets are formed when a critical supersaturation for the available cloud condensation nuclei (CCN) is exceeded and haze particles are not explicitly resolved. Here, we develop and adapt haze-capable bin and Lagrangian microphysics schemes to properly resolve the activation and deactivation processes. Results are compared with the Twomey-type …

Scientists And Activists Work To Save The Planet, Myriam G. Vidal Valero

Capstones

Climate change and human intervention in nature are affecting people, ecosystems and ways of living all over the world. This portfolio of environmental pieces showcases the dire consequences of not addressing these issues, how solutions can be reached and the challenges facing those who try to change things.

Analysis Of The Stress Distribution Of North Anatolian Fault Zone For The Part Between Amasya-Tokat Cities, Ayça Çirmik, Ufuk Aydin, Oya Ankaya Pamukçu, Fikret Doğru

Bulletin of the Mineral Research and Exploration

Tectonic forces formed in the continental crust, cause permanent changes in stress, compression and deformation. The amplitudes of earthquake waves vary with the stress/strain distribution in the crust. In this study, the change of stress / strain and regional absorption coefficient, which is effective in tectonic forces caused by elastic deformation energy accumulating in the brittle crust over time, was investigated. The study area is the middle part of the North Anatolian Fault Zone and the area formed by Ezinepazarı fault zone and Merzifon fault zone. In this area, Coulomb stress analysis was carried out by using the focal mechanism …

Two Substellar Survivor Candidates; One Found And One Missing, T. Von Hippel, N. Walters, J. Farihi, T.R. Marsh, E. Breedt, P.W. Cauley, J.J. Hermes

Publications

This study presents observations of two possible substellar survivors of post-main sequence engulfment, currently orbiting white dwarf stars. Infrared and optical spectroscopy of GD 1400 reveal a 9.98 h orbital period, where the benchmark brown dwarf has ��2 = 68 ± 8 MJup, ��eff ≈ 2100 K, and a cooling age under 1 Gyr. A substellar mass in the lower range of allowed values is favoured by the gravitational redshift of the primary. Synthetic brown dwarf spectra are able to reproduce the observed CO bands, but lines below the bandhead are notably overpredicted. The known infrared excess towards PG 0010+281 …

Fairness And Privacy In Machine Learning Algorithms, Neha Bhargava

Master of Science in Computer Science Theses

Roughly 2.5 quintillion bytes of data is generated daily in this digital era. Manual processing of such huge amounts of data to extract useful information is nearly impossible but with the widespread use of machine learning algorithms and their ability to process enormous data in a fast, cost-effective, and scalable way has proven to be a preferred choice to glean useful insights and solve business problems in many domains. With this widespread use of machine learning algorithms there has always been concerns about the ethical issues that may arise from the use of this modern technology. While achieving high accuracies, …

Decreasing Trash In Local Creeks: A Program Evaluation Of The City Of San Jose’S Direct Discharge Trash Control Program, Lakeisha Bryant

Master's Projects

The entire San Francisco Bay was once a navigable waterway in the 1850s during the Gold Rush era. Large amounts of sediment from upstream erosion and mining flowed to the bay resulting in the downsizing of the bay’s square miles (Environmental Protection Agency, 2022). As a result of intense development on the bay shores and adjacent lands, the bay faces several challenges that affect its water quality and threatens aquatic ecosystems. Pesticides, mercury, metals, and pathogens are just a few substances in the bay that cause unhealthy conditions for aquatic life and threaten human health. California’s Water Resources Control Board …

Discourse, Power Dynamics, And Risk Amplification In Disaster Risk Management In Canada, Martins Oluwole Olu-Omotayo

Electronic Thesis and Dissertation Repository

The domain of disaster risk management is rife with discursive contentions, whereby dominant discourses amplify the powers of risk actors to precipitate and reinforce political, economic, and environmental inequalities that predispose different sections of the population to unequal disaster risk vulnerabilities. This thesis identified important actors (government, risk experts, media, and NGOs) that shape the power dynamics in disaster risk management in Canada and explained their roles, influences, and the dimensions in which their powers negotiate each other through risk discourses. The patterns of these power dynamics in the three aspects of power –communication, assessment, and social trust –were also …

Towards A Machine Learning-Based Digital Twin For Non-Invasive Human Bio-Signal Fusion, Izaldein Al-Zyoud, Fedwa Laamarti, Xiaocong Ma, Diana Tobón, Abdulmotaleb Elsaddik

Computer Vision Faculty Publications

Human bio-signal fusion is considered a critical technological solution that needs to be advanced to enable modern and secure digital health and well-being applications in the metaverse. To support such efforts, we propose a new data-driven digital twin (DT) system to fuse three human physiological bio-signals: heart rate (HR), breathing rate (BR), and blood oxygen saturation level (SpO2). To accomplish this goal, we design a computer vision technology based on the non-invasive photoplethysmography (PPG) technique to extract raw time-series bio-signal data from facial video frames. Then, we implement machine learning (ML) technology to model and measure the bio-signals. We accurately …

Transposición Didáctica Para La Enseñanza De La Matemática Avanzada Por Medio De Gamificación, Juan David Firigua Bejarano, Karen Giset Duarte Moyano, Jesús Antonio Villarraga Palomino

Educación

El presente proyecto de investigación, tuvo como propósito diseñar escenarios gamificados acordes a la Transposición Didáctica en la enseñanza y aprendizaje de conceptos de matemática avanzada; Teselados, Fractales, Geometría Esférica, Teoría de Grafos y Topología. Esta investigación se fundamentó en la teoría de la Transposición Didáctica propuesta por Chevallard (1997) y las dinámicas de los entornos Gamificados por Werbach y Hunter (2015). Se desarrolló una metodología de enfoque cualitativo, dirigido a estudiantes del grado décimo del Colegio Fundación Manuel Aya, Fusagasugá, la muestra la conformo sesenta y siete (67) estudiantes. Para esto, se caracterizó la población por medio de diversas …

Examining The Impact Of Covid-19 On The Education And Development Of American Students, Riley Fortin '25

Student Research

After the COVID-19 pandemic, the vast majority of American children have fallen behind on core subjects due to the ultimate ineffectiveness of remote learning. This study attempts to discover the degree to which children have fallen behind through the trends in the National Association of Educational Procurement’s two most recent testing years. A database accessed from Google has been analyzed, filtered by state and visualized in tables in order to indicate any possible trends as a result of remote learning brought on by the pandemic. By looking at data in seven different states across the country, there is a notable …

Sexual And Reproductive Health Disparities For Lgbtq+ Patients, Lauren Del Rosario

Student Research

As of 2022, 7.1% of Americans identify as LGBTQ. Members of the LGBTQ+ community in the United States experience greater health disparities than their heterosexual counterparts due to structural inequity: in addition to having minority status within the United States, there is a lack of education and research about LGBTQ+ health-related issues as well as restrictive policies that limit access to health care and other health benefits. As a result, the LGBTQ+ community is more prone to developing certain conditions, have less access to health care, and have worse health outcomes. However, LGBTQ+ visibility has increased dramatically within the last …

Outdoor Recreation And Its Effect On Our Relationship With The Environment, Martin Brannaman

Department of Environmental Studies: Undergraduate Student Theses

This study was conducted at the University of Nebraska Outdoor Adventure Center. This study employed a pre-post retrospective assessment looking at individuals' connection with nature after embarking on a direct outdoor experience. A direct outdoor experience is when an individual is outside and not surrounded by manmade structures (Kil, 2016). I believe that after a direct outdoor experience the sample group will have a significant change in their connection to nature. The objective is to measure change in a group's connection to nature, through the Connectedness to Nature Scale (CNS, Mayer & Frantz, 2004). The population was a group of …

Eastern Redcedar Reduces Regeneration And Diversity In The Forests Of The Niobrara River Valley, Abigail Ridder

Department of Environmental Studies: Undergraduate Student Theses

Boundary forests are found growing interdigitated with grasslands across the Great Plains. The Niobrara River valley boundary forest has a unique composition of species not seen anywhere else in North America. Encroachment of eastern redcedar (Juniperus virginiana L.) into grasslands and forests is significantly increasing eastern redcedar’s presence in the Niobrara River Valley as well as in the rest of the Great Plains region. This tree species is capable of significantly decreasing recruitment and diversity in grasslands, which can change the composition of the entire ecosystem. However, the effect of eastern redcedar on recruitment and diversity of naturally forested ecosystems …

Literature Review On Water Desalination Plant Production And Brine Disposal Methods, Grace Kollars

Department of Environmental Studies: Undergraduate Student Theses

Water scarcity is an issue all around the world because people have a lack of clean and available drinking water. One way this issue can be eased and people can have more access to water is implementing water desalination plants around the world. Since most of the water on earth cannot be drunk, there are ways to turn the over abundance of salty waters we have on this planet into fresh, drinkable water to ease the water insecurity. There are many methods out there that can be used for water desalination, most of them involving membrane technologies. The most efficient …

On The Relative Importance Of Offshelf/Onshelf Drivers Of Variability In Mcdw Inventory On The Amundsen Shelf, Antarctica, Pierre St-Laurent, S. E. Stammerjohn, T. Maksym, R. M. Sherrell

Presentations

Ice shelves in the Amundsen Sea (west Antarctica) are melting rapidly and may raise global sea levels substantially over the coming century through reduced buttressing. The high basal melt rates are associated with the presence of warm modified Circumpolar Deep Water (mCDW) that intrudes across the continental shelf and melts the floating portion of the ice sheet from its base near the grounding zone. How much mCDW is present on the continental shelf (its volume inventory) is thus thought to be a key proxy for the year-to-year variability in ice shelf melt rates. Over the past decade, the literature has …

Spatial Validation Of Agent-Based Models, Kristoffer Wikstrom, Hal T. Nelson

Public Administration Faculty Publications and Presentations

This paper adapts an existing techno–social agent-based model (ABM) in order to develop a new framework for spatially validating ABMs. The ABM simulates citizen opposition to locally unwanted land uses, using historical data from an energy infrastructure siting process in Southern California. Spatial theory, as well as the model’s design, suggest that adequate validation requires multiple tests rather than relying solely on a single test-statistic. A pattern-oriented modeling approach was employed that first mapped real and simulated citizen comments across the US Census tract. The suite of spatial tests included Global Moran’s I, complemented with bivariate correlations, as well as …

Analyzing Recycling Options For Wind Turbine Blade Waste, Awinita Bunner

Department of Environmental Studies: Undergraduate Student Theses

The purpose of this study was to conduct a systematic literature review to identify recycling options for wind turbine blade waste. Wind energy is a rapidly growing energy source due to its renewability and accessibility. However, the turbines that produce this energy have blades that must be replaced throughout the turbine’s lifetime. The standard disposal method of decommissioned blades is the landfill. However, problems are arising within states as landfills are being overrun by the wind turbine blades once they reach their end-of-life. Conducting this study aims to provide a list of recycling options and provide an evaluation of each …

An Imaging Mass Spectrometry Investigation Into The N-Linked Glycosylation Landscape Of Pancreatic Ductal Adenocarcinoma And The Development Of Associated Tools For Enhanced Glycan Separation And Characterization, Colin Mcdowell

MUSC Theses and Dissertations

The severity of pancreatic ductal adenocarcinoma (PDAC) is largely attributed to a failure to detect the disease before metastatic spread has occurred. CA19-9, a carbohydrate biomarker, is used clinically to surveille disease progression, but due to specificity challenges is not suitable for early discovery. As CA19-9 and other prospective markers are glycan epitopes, there is great clinical interest in understanding the glycobiology of pancreatic cancer. Unfortunately, few studies have been able to link glycosylation changes directly to pancreatic tumors and instead have focused on peripheral glycan alterations in the serum of PDAC patients. To address this gap in our understanding, …