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2018

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Articles 271 - 300 of 13643

Full-Text Articles in Physical Sciences and Mathematics

Syntheses Of A Tin (Iv) Meso-Tetra(4-Pyridyl) Porphyrin Dichloride-Tetrachlorobis (Bipy)2 Ruthenium (Ii) Complex And Studies Of Photophysical Properties Of 1-Nitropyrene, Phillip Sharp Dec 2018

Syntheses Of A Tin (Iv) Meso-Tetra(4-Pyridyl) Porphyrin Dichloride-Tetrachlorobis (Bipy)2 Ruthenium (Ii) Complex And Studies Of Photophysical Properties Of 1-Nitropyrene, Phillip Sharp

Electronic Theses and Dissertations

Development of a photosensitizer that can work in both aerobic and anaerobic environments would increase the robustness of the cancer treatment known as photodynamic therapy. The development of a photosensitizer was first attempted by synthesizing a tin (IV) meso-tetra (4-pyridyl) porphyrin dichloride-tetrachlorobis (Bipy)2 ruthenium (II) complex. The synthesize of the tin porphyrin was done by a method from literature and had a percent error of 31.58 and 37.31 when comparing the theoretical percentages of carbon (55.39) and nitrogen (12.92) meaning that photosensitizer was not synthesized.

The second type of chromophore that was studied was 1-nitropyrene do determine if it …


Delineation Of Karst Potential Using Lidar And Gis Analyses, Fort Hood Military Installation, Texas, Colby Reece Dec 2018

Delineation Of Karst Potential Using Lidar And Gis Analyses, Fort Hood Military Installation, Texas, Colby Reece

Electronic Theses and Dissertations

ABSTRACT

Traditional karst surveys require extensive field investigations to completely characterize large areas. They are often time-consuming, requiring up to several years to collect and categorize data. Bias is given to areas that are most easily accessible and false negatives are common. The implementation of geographic information systems (GIS) has aided in the aggregation and standardization of karst data; however, these systems have also been used to develop terrain models that allow the user to remotely delineate sinkholes and other surficial features. The Fort Hood Military Installation is a karst landscape that has been altered significantly for use in military …


Mechanisms For The Incorporation And Distribution Of Radionuclides In Near-Surface Fallout, Marc Alan Fitzgerald Dec 2018

Mechanisms For The Incorporation And Distribution Of Radionuclides In Near-Surface Fallout, Marc Alan Fitzgerald

UNLV Theses, Dissertations, Professional Papers, and Capstones

Fallout is the radioactive glass formed from a mixture of vaporized anthropogenic materials with proximate environmental material. These glassy byproducts constitute a compositional record of environmental materials such as soil and vapor precursors that are responsible for chemical heterogeneity in the glasses. The work of this dissertation is to untangle these different sources of compositional heterogeneity, distinguishing low-abundance vaporized anthropogenic-rich material from natural compositions, in order examine soil behavior and chemical evolution during fallout formation. Unfortunately, mixing convolutes the multivariate elemental relationships in these melts due to overlapping element abundances that might distinguish different source materials and chemical behaviors, making …


Uas-Based Object Tracking Via Deep Learning, Marc Dinh Dec 2018

Uas-Based Object Tracking Via Deep Learning, Marc Dinh

UNLV Theses, Dissertations, Professional Papers, and Capstones

Tracking is the task of identifying an object of interest and detect its position over time, and has numerous applications like surveillance, security and traffic control. In present times, unmanned aerial vehicles (UAV) have been more and more common which provides us with a new and less explored domain, with an ideal vantage point for surveillance and monitoring applications.. Aerial tracking is a particularly challenging task as it introduces new environmental variables such as rapid motion in 3D space. We propose a new deep learned tracker architecture catered to aerial tracking.

First, a study of six state-of-the-art deep learned trackers …


Application Of Machine Learning Techniques In Credit Card Fraud Detection, Ronish Shakya Dec 2018

Application Of Machine Learning Techniques In Credit Card Fraud Detection, Ronish Shakya

UNLV Theses, Dissertations, Professional Papers, and Capstones

Credit card fraud is an ever-growing problem in today’s financial market. There has been a rapid increase in the rate of fraudulent activities in recent years causing a substantial financial loss to many organizations, companies, and government agencies. The numbers are expected to increase in the future, because of which, many researchers in this field have focused on detecting fraudulent behaviors early using advanced machine learning techniques. However, the credit card fraud detection is not a straightforward task mainly because of two reasons: (i) the fraudulent behaviors usually differ for each attempt and (ii) the dataset is highly imbalanced, i.e., …


Estimation Of The Parameters In A Spatial Regressive-Autoregressive Model Using Ord's Eigenvalue Method, Sajib Mahmud Mahmud Tonmoy Dec 2018

Estimation Of The Parameters In A Spatial Regressive-Autoregressive Model Using Ord's Eigenvalue Method, Sajib Mahmud Mahmud Tonmoy

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this thesis, we study one of Ord's (1975) global spatial regression models.

Ord considered spatial regressive-autoregressive models to describe the interaction

between location and a response variable in the presence of several covariates. He also

developed a practical estimation method for the parameters of this regression model

using the eigenvalues of a weight matrix that captures the contiguity of locations.

We review the theoretical aspects of his estimation method and implement it in the

statistical package R.

We also implement Ord's methods on the Columbus, Ohio, crime data set from the

year 1980, which involves the crime rate of …


Design And Preliminary Evaluation Of A Supercritical Carbon Dioxide Brayton Cycle For Solar Dish Concentrator Clean Energy Production, Danielle Nobles-Lookingbill Dec 2018

Design And Preliminary Evaluation Of A Supercritical Carbon Dioxide Brayton Cycle For Solar Dish Concentrator Clean Energy Production, Danielle Nobles-Lookingbill

UNLV Theses, Dissertations, Professional Papers, and Capstones

As we move toward energy independence and more ambitious clean energy goals, solar energy research must push the efficiency limits of traditional energy generation systems. Increases in efficiency can be achieved by increasing the hot temperature of the power cycle. Recent research demonstrates the potential for increased efficiency and a vastly smaller component size when supercritical carbon dioxide Brayton power cycles are used. Concentrated solar and nuclear heat sources are capable of achieving the high working fluid temperatures needed for significant efficiency gains. This NSF EPSCoR funded, experimental research system is designed to exploit the uniquely immense solar irradiance of …


Scheduling Two Machines With Dissimilar Costs, Madhurupa Moitra Dec 2018

Scheduling Two Machines With Dissimilar Costs, Madhurupa Moitra

UNLV Theses, Dissertations, Professional Papers, and Capstones

We consider two devices, which has states ON and OFF. In the ON state, the devices use their full power whereas in the OFF state the devices consume no energy but a constant cost is associated with switching back to ON. Such two devices are configured with different run and power-up costs on which a sequence of jobs must be processed. The object is to minimize the cost. Such systems are widely used to conserve energy, for example, to speed scale CPUs, to control data centers, or to manage renewable energy.

The problems are studied in the framework of online …


Effects Of Ambient Air Pollution On Asthma-Related Emergency Department Visits Within The Las Vegas Metropolitan Area, Loiren E. Monardes Dec 2018

Effects Of Ambient Air Pollution On Asthma-Related Emergency Department Visits Within The Las Vegas Metropolitan Area, Loiren E. Monardes

UNLV Theses, Dissertations, Professional Papers, and Capstones

The objective of this research was to evaluate the risk for asthma-related Emergency Department visits and their association with ambient air pollution within the Las Vegas metropolitan area. All data were aggregated by date and ZIP Code. The association was analyzed by applying the distributed lag non-linear model in an attempt to identify elevated concentrations of specific air pollutants

as triggers and their delayed effects (lag days). Relative Risk (RR) and 95% confidence intervals were produced, while adjusting for socioeconomic status. This ecological population-based study analyzed daily asthma counts of Emergency Department visits from January 1st, 2009 to December 31st, …


Examining Environmental Hazards In Rental Homes And Habitability Laws In Clark County, Nevada, Jorge Luis Bertran Dec 2018

Examining Environmental Hazards In Rental Homes And Habitability Laws In Clark County, Nevada, Jorge Luis Bertran

UNLV Theses, Dissertations, Professional Papers, and Capstones

It is well established that home conditions are linked to the health outcomes of occupants. There are over 880,000 housing units in Clark County, Nevada; nearly half of those are renter-occupied units (ROUs). Currently, there is limited research on the characteristics of environmental hazards found in Clark County ROUs and the strength of habitability statutes created to protect tenants from substandard housing. Understanding how renters in Clark County are affected by environmental hazards in ROUs and the processes by which landlords and tenants resolve grievances related to those hazards would benefit public health. It would enhance the ability to quickly …


Modeling The Bioactivation And Subsequent Reactivity Of Drugs, Tyler Brian Hughes Dec 2018

Modeling The Bioactivation And Subsequent Reactivity Of Drugs, Tyler Brian Hughes

Arts & Sciences Electronic Theses and Dissertations

Metabolism can convert drugs to harmful reactive metabolites that conjugate to DNA and off-target proteins. Reactive metabolites are a significant driver of both drug candidate attrition and withdrawal from the market of already approved drugs. Unfortunately, reactive metabolites are difficult to study in vivo, because they are transitory and generally do not circulate. Instead, this work computationally models both metabolism and reactivity. Using deep learning, predictive models were developed for the metabolic formation of quinones and epoxides, which together account for about half of known reactive metabolites. Additionally, an accurate model of DNA and protein reactivity was constructed, which predicts …


Grammar And Variation: Understanding How Cis-Regulatory Information Is Encoded In Mammalian Genomes, Dana Michele King Dec 2018

Grammar And Variation: Understanding How Cis-Regulatory Information Is Encoded In Mammalian Genomes, Dana Michele King

Arts & Sciences Electronic Theses and Dissertations

Understanding how genotype leads to phenotype is key to understand both the development and dysfunction of complex organisms. In the context of regulating the gene expression patterns that contribute to cell identity and function, the goal of my thesis research is to how changes in genome sequence may impact impact gene expression by determining how sequence features contribute to regulatory potential. To accomplish this goal, I first leveraged the key regulatory role of pluripotency transcription factors (TFs) in mouse embryonic stem cells (mESCs) and tested synthetically generated and genomic identified combinations of binding site for four TFs, OCT4, SOX2, KLF4, …


Anodic Cyclization Reaction: Manipulation Of Reaction Pathway And Efforts To Radical Cation And Radical Intermediate, Ruozhu Feng Dec 2018

Anodic Cyclization Reaction: Manipulation Of Reaction Pathway And Efforts To Radical Cation And Radical Intermediate, Ruozhu Feng

Arts & Sciences Electronic Theses and Dissertations

In recent years, synthetic chemists have been expressing significant interest in electro-organic synthetic methods. This interest is being fueled by the existence of an increasing number of successful methods in the literature and the availability of new electrochemical equipment that removes the barrier to attempting an electrolysis reaction for the first time. Yet while these developments have fueled growth in some areas of electro-organic synthesis (the recycling of chemical catalysts for example), other areas remain underdeveloped. One such area is the exploration of reactions that can be triggered directly as an electrode surface without the use of any chemical reagent. …


Tunable Electronic And Optical Properties Of Low-Dimensional Materials, Shiyuan Gao Dec 2018

Tunable Electronic And Optical Properties Of Low-Dimensional Materials, Shiyuan Gao

Arts & Sciences Electronic Theses and Dissertations

Two-dimensional (2D) materials with single or a few atomic layers, such as graphene, hexagonal boron nitride (h-BN) and transition metal dichalcogenides (TMDCs), and the heterostructures or one-dimensional (1D) nanostructures they form, have attracted much attention recently as unique platforms for studying many condensed-matter phenomena and holds great potentials for nanoelectronics and optoelectronic applications. Apart from their unique intrinsic properties which has been intensively studied for over a decade by now, they also allow external control of many degrees of freedom, such as electrical gating, doping and layer stacking. In this thesis, I present a theoretical study of the electronic and …


Efficient And Practical Composition Of Lock-Free Data Structures, Neha Bajracharya Dec 2018

Efficient And Practical Composition Of Lock-Free Data Structures, Neha Bajracharya

UNLV Theses, Dissertations, Professional Papers, and Capstones

A concurrent data object is lock-free if it guarantees that at least one, among all concurrent operations, finishes after a finite number of steps. In other words, a lock free technique guarantees that some thread always makes progress. Lock-free data objects offer several advantages over their blocking counterparts, such as being immune to deadlocks and priority inversion, and typically provide high scalability and performance, especially in shared memory multiprocessor architectures.

Composition of data structures is a powerful approach to combine simple data structures to create more complex ones. It works as a building block for many advanced useful data structures. …


Combinatorial Ant Optimization And The Flowshop Problem, Tasmin Chowdhury Dec 2018

Combinatorial Ant Optimization And The Flowshop Problem, Tasmin Chowdhury

UNLV Theses, Dissertations, Professional Papers, and Capstones

Researchers have developed efficient techniques, meta-heuristics to solve many Combinatorial Optimization (CO) problems, e.g., Flow shop Scheduling Problem, Travelling Salesman Problem (TSP) since the early 60s of the last century. Ant Colony Optimization (ACO) and its variants were introduced by Dorigo et al. [DBS06] in the early 1990s which is a technique to solve CO problems. In this thesis, we used the ACO technique to find solutions to the classic Flow shop Scheduling Problem and proposed a novel method for solution improvement. Our solution is composed of two phases; in the first phase, we solved TSP using ACO technique which …


Design, Layout, And Testing Of Sige Apds Fabricated In A Bicmos Process, Dane Laurence Gentry Dec 2018

Design, Layout, And Testing Of Sige Apds Fabricated In A Bicmos Process, Dane Laurence Gentry

UNLV Theses, Dissertations, Professional Papers, and Capstones

This Thesis is concerned with the design, layout, and testing of avalanche photodiodes (APDs). APDs are a type of photodetector and, thus, convert light signals into electrical signals (current or voltage). APDs can be fabricated using silicon (Si). In this Thesis, however, three integrated circuit (IC) chips containing various silicon-germanium (SiGe) APDs with different sizes, structures, and geometries were designed, laid out, and fabricated using the Austriamicrosystems (AMS) 0.35μm SiGe BiCMOS (S35) process. This was done in order to compare SiGe APDs to Si only APDs and investigate the hypothesis that SiGe APDs are capable of detecting longer wavelengths than …


Prokaryotic Diversity And Aqueous Geochemistry Of Subsurface Environments Of The Death Valley Regional Flow System, Joshua David Sackett Dec 2018

Prokaryotic Diversity And Aqueous Geochemistry Of Subsurface Environments Of The Death Valley Regional Flow System, Joshua David Sackett

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation summarizes over four years of effort towards the completion of a Ph.D. in Biological Sciences. The work presented in this document covers a broad range of topics, but a central unifying theme is prokaryotic life in the continental subsurface. The work presented in each chapter relied heavily on cultivation-independent methods for assessing prokaryotic communities, including prokaryotic community structure reconstruction from high-throughput sequencing of 16S rRNA gene libraries and single-cell genome analysis of novel uncultivated bacteria.

Chapter 2 examines the aqueous geochemistry and prokaryotic diversity of Devils Hole, a cavernous limnocrene and sole natural habitat for the critically endangered …


Optical Micro-Seismometer Based On Evanescent Field Perturbation Of Whispering Gallery Modes, Jaime Da Silva Dec 2018

Optical Micro-Seismometer Based On Evanescent Field Perturbation Of Whispering Gallery Modes, Jaime Da Silva

Mechanical Engineering Research Theses and Dissertations

This thesis proposes a light-weight, compact, and accurate optical micro-seismometer that could be used in many applications, such as planetary exploration. The sensor proposed here is based on the principle of whispering gallery optical mode (WGM) resonance shifts of a dielectric micro-resonator due to disturbances of its evanescent field. The micro-seismometer could be used in place of the traditional bulky seismometers. The design of a waveguide-resonator and mechanical structure to disturb the evanescent field are presented. A proof-of-concept a seismometer model that uses a 5µm ring resonator is numerically tested with actual seismic data. The results show that a WGM-based …


An Analysis Of Mixed-Layer Clay Minerals And Major Element Geochemical Trends In Middle-Upper Pennsylvanian-Aged Paleosols As A Proxy For Characterizing Basin-Wide Diagenetic Patterns And The Paleoenvironment Of The Illinois Basin, U.S.A., Julia A. Mcintosh Dec 2018

An Analysis Of Mixed-Layer Clay Minerals And Major Element Geochemical Trends In Middle-Upper Pennsylvanian-Aged Paleosols As A Proxy For Characterizing Basin-Wide Diagenetic Patterns And The Paleoenvironment Of The Illinois Basin, U.S.A., Julia A. Mcintosh

Earth Sciences Theses and Dissertations

Pennsylvanian-aged paleosols from four Illinois Basin (IB) cores were sampled to characterize clay mineralogy, paleosol morphology, and major element geochemistry. This data combined with X-ray diffraction (XRD) and X-ray fluorescence (XRF) data from two other stratigraphically equivalent cores were used to better understand basin-wide diagenetic patterns. Paleosols unimpacted by diagenesis are considered reliable proxies for continued geochemical analyses and paleoclimate interpretations of middle to late Pennsylvanian (Desmoinesian-Missourian) low-latitude environments.

Reichweite Ordering, as determined from XRD analysis ofprofiles, indicates that diagenesis impacted the deep interior of the basin and the southern portion of the basin. Further investigation of illitization mechanisms derived …


Photo-Isomerizable Complementary Hydrogen Bond Arrays, Jeffrey S. Pleizier Dec 2018

Photo-Isomerizable Complementary Hydrogen Bond Arrays, Jeffrey S. Pleizier

Electronic Thesis and Dissertation Repository

The use of light as an external stimulus provides a non-invasive technique to induce large changes in physical and chemical properties of a substrate. The incorporation of a photochromic subunit into supramolecular polymeric systems therefore adds a potential "smart" quality for polymer manipulation. The azo moiety (-N=N-) is one of the most popular photochromic units as the trans to cis isomerization results in a large degree of spatial rearrangement. This present thesis exploits the azo group by its incorporation into complementary hydrogen bonded complexes. Hydrogen bonding acceptor groups attached to the periphery of the central azo photoswitch provided strong complexation …


Validating And Highlighting The Advantages Of The Optimal Estimation Method For Rayleigh Lidar Middle Atmospheric Temperature Retrievals, Ali Jalali Dec 2018

Validating And Highlighting The Advantages Of The Optimal Estimation Method For Rayleigh Lidar Middle Atmospheric Temperature Retrievals, Ali Jalali

Electronic Thesis and Dissertation Repository

An improved understanding of temperature variations in Earth’s middle atmosphere is important for the improvement of our understanding of climate and weather on the surface. The optimal estimation method (OEM) is an inversion modeling approach, which uses regularized nonlinear regression to retrieve, in this case, the temperature of Earth’s middle atmosphere using Rayleigh-scatter lidar measurements. The OEM regularization term is the a priori knowledge of the atmospheric temperature profile. In this thesis I use lidar temperatures in the altitude range 30–110km to construct a temperature climatology using over 500 nights of measurements obtained by the Purple Crow Lidar in London, …


Inequality, Rubber, And Thermodynamics In Indonesia, Ernest M. Oleksy Dec 2018

Inequality, Rubber, And Thermodynamics In Indonesia, Ernest M. Oleksy

The Downtown Review

Intersectionality has led the charge in ensuring that workplace justice is assured to all people, irrespective of their identities. While intersectionality is a useful theory for explaining inequality, what must not be understated is the contributions that postcolonialism and the blue-collar working identity can have on harsh working conditions. Particularly, miners in Indonesia have had to work in very hostile environments where they are at-risk for sulfur poisoning as they mine for materials to vulcanize rubber. This article serves two purposes. The first is to call attention to how place can help explain the differential experiences of miners in the …


The Chemical Causes And Social Effects Of Acid Rain, Ernest M. Oleksy Dec 2018

The Chemical Causes And Social Effects Of Acid Rain, Ernest M. Oleksy

The Downtown Review

While global warming tends to dominate the collective conscious for environmentalism of academics and the public alike, many other physical phenomena bear serious implications for humanity's future. One such phenomenon, acid rain, has been under-reported considering how damaging it is to the ecosystem and how much politicking is involved when determining how to address it. This article serves two purposes. The first is to inform readers of the basic chemical processes underlying acid rain and why it is damaging to organisms. The second is to inform readers of how acid rain has been portrayed by other publications, like the National …


The Theory Of Relativity And Applications: A Simple Introduction, Ellen Rea Dec 2018

The Theory Of Relativity And Applications: A Simple Introduction, Ellen Rea

The Downtown Review

This paper will provide a brief overview of the theory of relativity by looking at its two parts: special relativity and general relativity. It will omit most of the complex mathematics involved in order to focus on providing a more conceptual understanding. However, some simplified equations will be introduced to illustrate various aspects of the theory. Some of the experiments and scientific observations that support the theory as well as some of the scientific advances that emerged from the theory will also be discussed. Following the overview of the theory of relativity will be some of its applications in past …


An Examination Of The Death Penalty, Alexandra N. Kremer Dec 2018

An Examination Of The Death Penalty, Alexandra N. Kremer

The Downtown Review

The death penalty, or capital punishment, is the use of execution through hanging, beheading, drowning, gas chambers, lethal injection, and electrocution among others in response to a crime. This has spurred much debate on whether it should be used for reasons such as ethics, revenge, economics, effectiveness as a deterrent, and constitutionality. Capital punishment has roots that date back to the 18th century B.C., but, as of 2016, has been abolished in law or practice by more than two thirds of the world’s countries and several states within the United States. Here, the arguments for and against the death …


Secured Data Masking Framework And Technique For Preserving Privacy In A Business Intelligence Analytics Platform, Osama Ali Dec 2018

Secured Data Masking Framework And Technique For Preserving Privacy In A Business Intelligence Analytics Platform, Osama Ali

Electronic Thesis and Dissertation Repository

The main concept behind business intelligence (BI) is how to use integrated data across different business systems within an enterprise to make strategic decisions. It is difficult to map internal and external BI’s users to subsets of the enterprise’s data warehouse (DW), resulting that protecting the privacy of this data while maintaining its utility is a challenging task. Today, such DW systems constitute one of the most serious privacy breach threats that an enterprise might face when many internal users of different security levels have access to BI components. This thesis proposes a data masking framework (iMaskU: Identify, Map, Apply, …


The Investigation Of The Chlorine Initiated Oxidation Of 2-Phenylethanol And Stability Of Superalkali Lithium Substituted Silyls., Adam Otten Dec 2018

The Investigation Of The Chlorine Initiated Oxidation Of 2-Phenylethanol And Stability Of Superalkali Lithium Substituted Silyls., Adam Otten

Master's Theses

This thesis investigates the combustion potential of 2-phenylethanol and the superalkali properties of small lithium substituted silicon compounds. All combustion experiments were performed at the Advanced Light Source of Lawrence Berkeley National Laboratory at the Chemical Dynamics Beamline 9.0.2. The chlorine initiated oxidation of 2PE was investigated at 298 and 550 K using a multiplex photoionization mass spectrometer, coupled with the tunable vacuum ultraviolet radiation. Reaction products were identified using kinetic time traces and photoionization spectra.

Additionally, the stability of small superalkali silicon-lithium compounds has also been investigated. All structures and energetics were calculated using the CBS-QB3 composite method.

The …


Limit Properties Of Order Statistics, А. Madraximov, S. Kukieva Dec 2018

Limit Properties Of Order Statistics, А. Madraximov, S. Kukieva

Scientific journal of the Fergana State University

The paper studies the question of estimating the concentration function for the sums of minima of positive random variables.


Substantiation The Parameters Of The Cotton Cleaners’ Polyhedral Vibrating Fire-Bars, A. Djuraev, R.Kh. Maksudov, Sh. Shukhratov Dec 2018

Substantiation The Parameters Of The Cotton Cleaners’ Polyhedral Vibrating Fire-Bars, A. Djuraev, R.Kh. Maksudov, Sh. Shukhratov

Scientific journal of the Fergana State University

The article describes the principle of operation of the recommended multifaceted grate on elastic supports, as well as the results of the analysis of the grate oscillations, and the parameters are justified. The results of comparative production tests.