Physical Sciences and Mathematics Commons^™

Topology Identification In Distribution System Via Machine Learning Algorithms, Peyman Razmi, Mahdi Ghaemi Asl, Giorgio Canarella, Afsaneh Sadat Emami

Economics Faculty Publications

This paper contributes to the literature on topology identification (TI) in distribution networks and, in particular, on change detection in switching devices' status. The lack of measurements in distribution networks compared to transmission networks is a notable challenge. In this paper, we propose an approach to topology identification (TI) of distribution systems based on supervised machine learning (SML) algorithms. This methodology is capable of analyzing the feeder's voltage profile without requiring the utilization of sensors or any other extraneous measurement device. We show that machine learning algorithms can track the voltage profile's behavior in each feeder, detect the status of …

Coupled Deep-Mantle Carbon-Water Cycle: Evidence From Lower-Mantle Diamonds, Wenzhong Wang, Oliver Tschauner, Shichun Huang, Zhongqing Wu, Yufei Meng, Hans Bechtel, Ho Kwang Mao

Geoscience Faculty Research

Diamonds form in a variety of environments between subducted crust, lithospheric and deep mantle. Recently, deep source diamonds with inclusions of the high-pressure H O-phase ice-VII were discovered. By correlating the pressures of ice-VII inclusions with those of other high-pressure inclusions, we assess quantitatively the pressures and temperatures of their entrapment. We show that the ice-VII-bearing diamonds formed at depths down to 800 ± 60 km but at temperatures 200–500 K below average mantle temperature that match the pressure-temperature conditions of decomposing dense hydrous mantle silicates. Our work presents strong evidence for coupled recycling of water and carbon in the …

Control-Oriented Nonlinear Modeling Of Polyvinyl Chloride (Pvc) Gel Actuators, Mohammed Al-Rubaiai, Xinda Qi, Zachary Frank, Ryohei Tsuruta, Umesh Gandhi, Kwang J. Kim, Xiaobo Tan

Mechanical Engineering Faculty Research

Polyvinyl chloride (PVC) gel-based actuators are a new class of soft, electroactive polymer actuators with several attractive properties, including low cost, large compliance, large strain output, high-stress output, fast response, and stability against thermal influence. While PVC gel actuators are quickly gaining attention, they remain largely unexplored despite their great potential in a long list of applications compared with many other smart material actuators. In particular, little work has been reported on modeling nonlinear dynamics of PVC actuators. In this work a nonlinear, control-oriented Hammerstein model, with a polynomial nonlinearity preceding a transfer function, is proposed to capture the amplitude-dependent …

Cumulative Infiltration And Infiltration Rate Prediction Using Optimized Deep Learning Algorithms: A Study In Western Iran, Mahdi Panahi, Khabat Khosravi, Sajjad Ahmad, Somayeh Panahi, Salim Heddam, Assefa M. Melesse, Ebrahim Omidvar, Chang Wook Lee

Civil and Environmental Engineering and Construction Faculty Research

Study region: Sixteen different sites from two provinces (Lorestan and Illam) in the western part of Iran were considered for the field data measurement of cumulative infiltration, infiltration rate, and other effective variables that affect infiltration process. Study focus: Soil infiltration is recognized as a fundamental process of the hydrologic cycle affecting surface runoff, soil erosion, and groundwater recharge. Hence, accurate prediction of the infiltration process is one of the most important tasks in hydrological science. As direct measurement is difficult and costly, and empirical models are inaccurate, the current study proposed a standalone, and optimized deep learning algorithm of …

Real-Time Pm10 Emission Rates From Paved Roads By Measurement Of Concentrations In The Vehicle's Wake Using On-Board Sensors Part 2. Comparison Of Scamper, Traker™, Flux Measurements, And Ap-42 Silt Sampling Under Controlled Conditions, Dennis R. Fitz, Kurt Bullimer, Vic Etyemezian, Hampden D. Kuhns, John A. Gillies, George Nikolich, David E. James, Rodney Langston, Russell S. Merle Jr.

Civil and Environmental Engineering and Construction Faculty Research

Representative soil was evenly applied to an 800-m section of road surface. The test area was of sufficient length to allow for measurement at constant speeds of up to 72 km hr−1. SCAMPER and TRAKER™ mobile measurement vehicles made repeated test runs while an instrumented tower measured upwind-downwind horizontal PM10 flux. AP-42 methods were used to collect silt samples and calculate PM10 emission factors. Both silt loadings and vehicle speeds were varied during the experiment. Street sweeping the as-found roadway showed an initial rise in PM10 emission rates. Both TRAKER and SCAMPER measured rapid decay of PM10 emission rates after …

Climatic And Topographic Control Of The Stable Isotope Values Of Rivers On The South Island Of New Zealand, Matthew S. Lachniet, Christopher M. Moy, Christina Riesselman, Haroon Stephen, Andrew M. Lorrey

Geoscience Faculty Research

We show that climate and topography control the spatial distribution of stable isotope values on the South Island of New Zealand, based on a spatially dense (n = 193) river isotopic survey. Our data show a δ O minimum in isotope values east of the Southern Alps that demonstrates topographically driven continentality associated with the Southern Alps, which intersect the prevailing, moisture-laden westerlies. Our data define a South Island surface water line of δ H = 8.17 (±0.26) × δ O + 10.57 (±2.04), which is identical within 95% confidence intervals to the global and New Zealand meteoric water lines …

Plasma Aerodynamics: Experimental Quantification Of The Lift Force Generated On An Airfoil Using Plasma Actuation To Estimate Power Requirements In Small Uav Applications, Getachew Ashenafi

UNLV Theses, Dissertations, Professional Papers, and Capstones

This research addressed the amount of electric power required to induce specific changes in lift force using a NACA 2127 airfoil with a chord length of ~28 mm, connected to a micro load cell, in a wind tunnel of 103 square centimeter cross-section. A DBD plasma actuator supplied by a ZVS driven high voltage pulsed DC circuit, operating at a frequency of 17.4 kHz, was utilized for voltages of up to 5000 V. Two configurations of electrode gapping were compared to determine the efficient use of power. The configuration with a gap of ~1 mm between the upstream and downstream …

Do You Need A Break From Environmental Duties? Apply The Norm Activation Theory To Examine Pro Environmental Behaviors, Yanjia Yang

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study aimed at examining how social environmental norms affect tourists’ pro-environmental behaviors (PEBs) in the destination and home contexts by employing the focus theory of normative conduct and norm activation theory. It also tested the moderating effects of the belief of a vacation break from environmental duties and the mediating effect of personal norms in the relationships between social-environmental norms and PEBs. A total of 400 usable surveys was collected through an online survey. Both t-test and regression analysis techniques were employed to analyze the data. There were two major findings from this study. First, PEBs became weaker when …

Food Insecurity And Risky Sexual Behaviors Among College Students, Bertille Octavie Mavegam Tango Assoumou M

UNLV Theses, Dissertations, Professional Papers, and Capstones

Food insecurity and sexually transmitted infections (STIs) are growing public health problems in the United States. Young people in general, and particularly college students, exhibit high prevalence of food insecurity, STIs, and risky sexual behaviors (RSB). Food insecurity and STIs among college students can have short- and long-term impacts on their academic success and their lives. Several studies have reported an association between food insecurity and some risky sexual behaviors among specific populations including HIV-infected people and homeless people. However, little is known about the relationship between food insecurity and RSB among college students. Given the high prevalence of food …

Estimation Of Spatial Change In Cropland Area And Evaluation Of Irrigation Performance In Imperial Valley Using Remotely Sensed Data, Usha Poudel

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Imperial Valley (IV) in the US is an extensively irrigated agricultural region, which includes multiple crops changing on an annual and semiannual basis. The valley is facing grave concerns about water management due to its semi-arid environment, water intensive crops, and limited water supply. A simple, inexpensive, and repeatable method to detect changes in cropping patterns may assist irrigation managers to understand crop diversification and associated consumptive use. In addition, a spatial assessment of existing water irrigation system performance and productivity is crucial to benchmark and improve current water management strategies. This thesis estimates the spatial pattern of change …

Kaleidoscope Of Urban Evapotranspiration: Exploring The Science And Modeling Approaches, Rubab Saher

UNLV Theses, Dissertations, Professional Papers, and Capstones

Urban evapotranspiration is a complex physical process. It depends on various critical drivers, including the land surface temperature (LST), surface albedo, landscape types, and building orientations. All of these factors create difficulties in the estimation of evapotranspiration (ET) by changing the microclimate conditions. The literature has oversimplified microclimate conditions by considering temperature difference as the only variable defining climate. The physical process depends on land-use changes, building proximities, and landscape types. This study devised three objectives to understand the microclimate effects on ET.

In the first objective, land-use change effects on LST, surface albedo, and ET were analyzed over a …

Orbital Dynamics And Stability Of Circumbinary Planetary Systems And Small Bodies In The Solar System, Cheng Chen

UNLV Theses, Dissertations, Professional Papers, and Capstones

My main research focuses on the dynamics and stability of circumbinary planetary systems and of small bodies in the solar system. Unlike the two-body problem, the three-body problem is more complex as there are stronger interactions with two massive bodies in the system. In the outer solar system, the apsidal precession secular resonance with Neptune makes comets in the Kuiper belt unstable in the early stages of the solar system. This resonance a likely origin for the nitrogen-delivering comets that impacted the Earth bringing some of the nitrogen in the Earth’s atmosphere today. Beyond the solar system, we have observed …

Petrogenesis Of Hawaiian Lavas: Investigations Using Radiogenic And Non-Traditional Stable Isotopes, Christopher Defelice

UNLV Theses, Dissertations, Professional Papers, and Capstones

Earth’s mantle is the most voluminous part of the planet and is inaccessible to direct investigations. It is only possible to study it through indirect methods, such as the chemical makeup of erupted lavas. The Hawaiian Islands are thought to be the product of the mantle plume hypothesis, sometimes called a hot spot. Material from the Earth’s mantle is brought to the surface and erupted as magnesium rich lavas and form basalts. Hawaii is the longest lived active hot spot on Earth and makes it an ideal candidate for understanding the evolution of the Earth’s mantle and how lavas cool …

A Process For Adm-300 Radiation Detector Modernization For Military Applications, Caesar R. Pereira

UNLV Theses, Dissertations, Professional Papers, and Capstones

An investigation to re-evaluate the current use in military applications of the ADM-300 Multi-Functional Survey Instrument and its requirements are provided. This paper outlines a method to upgrade the ADM-300 due to its eventual obsolescence using newly developed requirements that meet the original justification for use in the USAF in 1992. The capabilities and features of various detectors are analyzed and compared to the ADM-300. Response curves are generated using Monte Carlo simulations. The detectors are prioritized based on their performance to create metrics. A metanalysis of the metrics is conducted to limit bias within the process and justify their …

Molybdenite Re–Os, Titanite And Garnet U–Pb Dating Of The Magushan Skarn Cu–Mo Deposit, Xuancheng District, Middle–Lower Yangtze River Metallogenic Belt, Yue Li, Feng Yuan, Simon M. Jowitt, Fangyue Wang, Xiangling Li, Yufeng Deng, Yunyue Wang, Taofa Zhou

Geoscience Faculty Research

© 2020 Elsevier B.V. The Magushan skarn Cu–Mo deposit is a representative example of the skarn mineralization occurring within the Xuancheng ore district of the Middle–Lower Yangtze River Metallogenic Belt of eastern China. The precise age of an ore deposit is important for understanding the timing of mineralization relative to other geological events in a region and to fully place the formation of a mineral deposit within the geological context of other processes that occur within the study area. Here, we present new molybdenite Re–Os and titanite and andradite garnet U–Pb ages for the Magushan deposit and use these data …

Distributions And Habitat Associations Of Blue Point Pyrgulopsis And Blue Point Tryonia, Chenoa Janine Wilcox

UNLV Theses, Dissertations, Professional Papers, and Capstones

Springsnails and other crenophilic species are often of conservation concern due to endemism, narrow habitat requirements, and susceptibility to habitat degradation. Because there is a distinct lack of natural history information for many of these organisms, management of species that are of concern is often based on data from non-target species related to the species of interest. In this thesis, I provide background information regarding springsnails in western North America (Chapter 1), describe a study investigating the distribution and habitat associations of two springsnails endemic to a single spring (Chapter 2), and provide supplemental information on habitat characteristics associated with …

Juvenile Conifer Growth And Regeneration Across Diverse Climatic And Environmental Conditions In The Southwestern United States, Nikki L. Pirtel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Juvenile conifer germination, growth, and survival will play important roles in the persistence of coniferous forests and woodlands in the southwestern United States (SWUS), yet it is unclear how juvenile conifers allocate aboveground and belowground early growth and if growth differs between conifer and ecosystem types. Descriptions of growth characteristics may allude to the types of stress juveniles experience in their environments, how they morphologically respond to stress, and how they may be able to survive stress to persist in their current locations or expand into new areas. In Chapter 1, I described the growth characteristics of 4 juvenile conifer …

Degradation Of Antibiotics In Aqueous Phase Using Pms Catalytic Decomposition With Zero-Valent Iron Nanoparticles Immobilized In Sba-15, Ahdee Bluma Zeidman

UNLV Theses, Dissertations, Professional Papers, and Capstones

Zero-valent iron nanoparticles (nZVI) have been studied as an option for soil remediation and water treatment for many years. The capability of nZVI to produce oxidation/reduction processes, depending on the reaction conditions, has attracted great interest with their major drawback being reactivity loss through agglomeration. The loss in nZVI surface area has been reported to be prevented through immobilization onto a porous media (e.g., SBA-15, MCM-41, or zeolites). In this work, a mesoporous silica structure (SBA-15) is used as an nZVI supporting material to enhance its reactivity and promote peroxymonosulfate (PMS) catalytic decomposition for the degradation of antibiotics in aqueous …

Dynamic Analysis Of A Microgrid Powered With An Inverter And Machine-Based Distributed Resources, Brandon William Blackstone

UNLV Theses, Dissertations, Professional Papers, and Capstones

The proliferation of renewable distributed energy resources, particularly photovoltaic (PV) power systems, and the increasing need for a reliable power supply has led to the concept of microgrids, a mini-grid that consists of locally connected power generation units and needs, able to operate connected or disconnected from the utility grid, using controlled and coordinated methods to provide for the users of the microgrid the best possible conditions for their needs. The main technical issues facing microgrids include some of the following, seamless transition from stand-alone to utility grid connected operation, how to preserve frequency and voltage stability, and provide the …

An Introduction To Federated Learning And Its Analysis, Manjari Ganapathy

UNLV Theses, Dissertations, Professional Papers, and Capstones

With the onset of the digital era, data privacy is one of the most predominant issues. Decentralized learning is becoming popular as the data can remain within local entities by maintaining privacy. Federated Learning is a decentralized machine learning approach, where multiple clients collaboratively learn a model, without sharing raw data. There are many practical challenges in solving Federated Learning, which include communication set up, data heterogeneity and computational capacity of clients. In this thesis, I explore recent methods of Federated Learning with various settings, such as data distributions and data variability, used in several applications. In addition, I, specifically, …

Extreme Event Reconstructions For The Upper Fraser River Basin, British Columbia, Canada, Inga K. Homfeld

UNLV Theses, Dissertations, Professional Papers, and Capstones

Spring freshets and summer droughts have recently worsened in the Fraser River Basin, British Columbia, Canada, with significant impacts to the keystone Pacific salmon populations, the food and economic sovereignty of over eighty First Nations, and the western Canadian economy. These extreme events present a potential risk since, unlike many large and less hydroclimatically-complex and/or empounded watersheds, the Fraser River Basin is susceptible to a combination of unregulated spring freshet and summer drought events even within the same year. A major limitation for understanding past and future extreme event risk in the Fraser River Basin is that observational streamflow datasets …

Climate And Soil Moisture Dynamics Inform Potential Climate Change Impacts On Available Moisture And Juvenile Tree Survival In Semiarid Forests, Carolyn R. Koehn

UNLV Theses, Dissertations, Professional Papers, and Capstones

Trees in semiarid forests and woodlands of the western United States need soil moisture to transpire and function. Juvenile trees are especially vulnerable during periods of low soil moisture as their rooting zones are smaller and shallower than those of adult trees. This thesis focuses on two soil moisture-driven aspects of semiarid forests that may be modified by climate change: seasonal soil moisture patterns and juvenile tree survival.

In chapter 1, I investigated the influence of precipitation on soil moisture across seasons, elevations, soil layers, and periods of low and high precipitation. I developed time-varying definitions of winter (snow accumulation), …

Exploring The Choiceless Cardinal Hierarchy, David Linkletter

UNLV Theses, Dissertations, Professional Papers, and Capstones

In 1971, Kunen proved that the Axiom of Choice imposes a ceiling on the large cardinal hierarchy [7]. Much like the assumption V ≠ L unlocks measurable cardinals and beyond, dropping the Axiom of Choice enables Reinhardt cardinals and stronger cardinals to be explored. Some major notions of large cardinals beyond choice have recently been standardized by Woodin et. al. [2], with questions raised regarding their interconnectedness. Part 1 of this dissertation partially answers two of those questions, while conjecturing, with a partial solution, a much stronger answer which would simplify the existing cardinal charts - that Regular Berkeley Cardinals …

A Fusion Of Remotely Sensed Data To Map The Impervious Surfaces Of Growing Cities Of Punjab, Pakistan, Binita Shrestha

UNLV Theses, Dissertations, Professional Papers, and Capstones

Urban population is expected to exceed 70% of the world’s total by the middle of the 21st century. Thus, growth in number as well as the sizes of the cities are certain in the near future. The urbanization rates will be much higher in the developing countries than the developed. Such phenomena are accompanied by conversion of land cover from its natural use to built up environment to accommodation growing population. Built up surfaces include road networks, buildings, parking lots and pathways. They are permanently impervious and hydrologically active surfaces. Large volume and discharges of runoff characterize impervious surfaces with …

Accretion And Debris Disc Dynamics Around Single And Higher-Order Star Systems, Jeremy L. Smallwood

UNLV Theses, Dissertations, Professional Papers, and Capstones

My research deals with highly topical areas of astrophysics, such as planet habitability, stellar evolution, the origin of fast radio bursts, the evolution of debris discs, and the dynamics of accretion discs in binary and higher-order star systems. Accretion discs around binary star systems are ubiquitous in the galaxy and planet formation is thought to occur within these discs. Circumbinary discs are commonly observed to be misaligned with respect to the binary orbital plane. A misaligned circumbinary disc eventually evolve to a stable orientation, either coplanar or polar with the binary orbital plane. The process of disc alignment has important …

Does Social Support Moderate The Association Between Income And Food Security Status Among Seniors Living In Southern Nevada?, Adugna Teka Siweya

UNLV Theses, Dissertations, Professional Papers, and Capstones

Background: Income is the strongest predictor of food insecurity among seniors, and social support also an essential factor to help mitigate the effects of food insecurity. However, little is known about the potential role that social support may play as a moderator of the association between income and food insecurity. Thus, we aim to examine social support as a moderator for the relationship between income and food insecurity among seniors. Methods: Logistic regression models were used to analyze data collected in 2019 from seniors residing in Southern Nevada. Predictors of food insecurity, sociodemographic factors, social support variables, and income and …

A Hyperelastic Porous Media Framework For Ionic Polymer-Metal Composites And Characterization Of Transduction Phenomena Via Dimensional Analysis And Nonlinear Regression, Zakai J. Olsen

UNLV Theses, Dissertations, Professional Papers, and Capstones

Ionic polymer-metal composites (IPMC) are smart materials that exhibit large deformation in response to small applied voltages, and conversely generate detectable electrical signals in response to mechanical deformations. The study of IPMC materials is a rich field of research, and an interesting intersection of material science, electrochemistry, continuum mechanics, and thermodynamics. Due to their electromechanical and mechanoelectrical transduction capabilities, IPMCs find many applications in robotics, soft robotics, artificial muscles, and biomimetics. This study aims to investigate the dominating physical phenomena that underly the actuation and sensing behavior of IPMC materials. This analysis is made possible by developing a new, hyperelastic …

Linking Extreme High Air Temperature Events To Wildfire And Environmental Variation To Water Balance Partitioning In The Western Us, Neil Savage

UNLV Theses, Dissertations, Professional Papers, and Capstones

Chapter 1

Wildfire activity has increased across the western United States in recent decades, causing significant damage to ecosystem services and human communities. The Sierra Nevada region, in particular, has experienced substantial increases in the ignition frequency, severity, and extent of large wildfires. To partly disentangle the complex processes underlying wildfire risk, I developed a simple approach to link natural wildfire ignition patterns to changing seasonal temperatures and extreme high and low air temperature events across the Sierra Nevada region from 1992—2015. Extreme event analyses focused on the association between the magnitude and frequency of occurrence of extreme temperature events …

Food Insecurity And Adiposity Among Children And Adults Nhanes 2015-2016, Denise Vidal

UNLV Theses, Dissertations, Professional Papers, and Capstones

Background: Obesity is a preventable disease that has been associated with many adverse health outcomes. A possible factor that may influence adiposity development is food insecurity. Although several epidemiological studies have been conducted examining the association between food insecurity and adiposity among children and adults, results have been inconsistent. Objective: This cross-sectional study investigates the relationship between food insecurity and adiposity among children and adults using recent data from a representative sample of the US population. Methods: We examined 3,391 adults and 2,837 children from the National Health and Nutrition Examination Survey (NHANES) 2015-2016. Household food insecurity was assessed using …

Comparing A New Algorithm For The Traveling Salesman Problem To Previous Deterministic And Stochastic Algorithms, Edward Friesema

UNLV Theses, Dissertations, Professional Papers, and Capstones

The challenges of drone navigation have driven many advances in the development of autonomous systems. Unmanned Autonomous Vehicles(UAVs) operate in a rapidly changing flight space and have to balance a complex set of constraints and objectives. Many of these objectives can be represented in variations of the classic Traveling Salesman Problem. Numerous approximate solutions to TSP have been proposed over the years, but these approaches have difficulty when adding new constraints that require rapid recalculation of the solution. Either they are fast but do not provide solutions that are close to the optimum, or they provide excellent solutions but they …