Physical Sciences and Mathematics Commons^™

Understanding The Promotion Effect: A Density Functional Theory Study Based On High Resolution Transmission Electron Microscopy Images For Mos2-Cobalt Promoted Interfaces, Manuel A. Ramos

Open Access Theses & Dissertations

Many studies had been done in order to understand promotion effect and structure/function in unsupported catalyst. Results indicated that d-electrons play an important role promoting catalytical active sites at the edges of MoS2 catalytically structures. Sulfur removal from crude oil, occurs on the edge of molybdenum di-sulfide (MoS2) nano structures, due to promotion of MoS2 nano structures with nickel or cobalt in sulfur-terminated or molybdenum-terminated edge planes. The promotion leads to formation of so-called CoMoS phase (MoS2/Co9S8) first discovered by meaning of Mössbauer spectroscopy, much more CoMoS phase usually called unsupported catalytical particles, have been topic of great interest in …

Iron And Manganese Based Nanomaterials For The Removal Of Selenite And Selenate From Aqueous Solution, Christina Marie Gonzalez

Open Access Theses & Dissertations

Selenium, a naturally occurring element in the environment, is an essential nutrient for humans and animals. However, there is a narrow range between selenium deficiency and toxicity. Selenium in natural waters generally has a concentration of < 10 ppb (parts per billion); however, in the San Joaquin Valley of California concentrations of selenium ranging from 140 to 1400 ppb have been observed. Anthropogenic practices such as agricultural irrigation drainage, coal burning power plants, combustion of fossil fuels, and mining operations are increasing selenium concentrations in aqueous environments. Once in aqueous environments, selenium exists primarily as the two inorganic oxoanions selenite (SeO32-) and selenate (SeO42-). Both of these selenium oxoanions are known to bioaccumulate and can cause embryotoxic and teratogenic effects to waterfowl. There has been a variety of treatment technologies developed for remediation of both selenium oxoanions in water including bacterial reduction, membrane filtration, chemical reduction, reverse osmosis, and solar ponds. However, these treatment technologies are not cost efficient. In this study an alternative treatment technique known as adsorption was used with three synthetic nanomaterials consisting of an iron oxide, manganese oxide, and an iron/manganese oxide. The pH profiles, time dependencies, competitive anion effects, and adsorption isotherms were performed with each of the nanomaterials for both selenite and selenate. In addition, X-ray absorption spectroscopy (XAS) studies were performed to determine both the oxidation state and binding coordination of the selenium oxoanion binding to the nanomaterials.

The investigation revealed the non microwave-assisted and microwave-assisted synthetic Fe3O4 and Mn3O4 nanomaterials, as well as the non microwave-assisted synthetic MnFe2O4 nanomaterial had the phases of magnetite, hausmannite, and Jacobsite, while the grain sizes were 27, 25, 25, 34, and 27 nm, respectively. The optimal binding of selenium oxoanions for all nanomaterials examined was reached at pH 4. Both non microwave-assisted and microwave-assisted Fe3O4 …

Modeling Geographic Awareness Of Road Networks For Consistency Verification, Ari Kassin

Open Access Theses & Dissertations

Problems related to transportation and inspection of valuable or sensitive assets such as commercial products and materials, cultural items and works of art, and hazardous materials share similarities and can be modeled by a core set of abstract entities including a payload, a vehicle, a driver, and an inspector. To make the load handling capabilities of security monitoring and inspection systems more scalable, security can be increased by reducing the variability of transportation routes to a finite set of authorized routes between trip origin and destination locations. Then trip anomalies, which are unexpected trip variations, can be used in inspection …

Microstructure And Property Evaluation Of Lifepo4 Thin Films For Application In Microbatteries, Jose Marcos Mares

Open Access Theses & Dissertations

The shortage of fossil fuels and the requirements to produce clean, environmental friendly, efficient, and economical energy are the principal problems in the context of energy technology for current and future generations. Therefore, advanced energy storage and conversion capabilities with higher capacity and efficiency are desired. Currently, there is an enormous interest in the development of high energy density rechargeable batteries for use in domestic applications, automotive industries and portable electronic applications. The present research focuses on the development of LiFePO4 thin films for solid-state thin-film microbatteries. The present effort was performed with a specific purpose of understanding the effect …

Test Case Automation For Specification Patterns System And Composite Propositions, Cuauhtemoc Munoz

Open Access Theses & Dissertations

Specifying software properties is a common activity in the software development process. Software properties are often written in a natural language such as English. However, the ambiguity in natural languages makes validation and verification time-consuming and error-prone. Specifying software properties in formal languages such as Linear Temporal Logic (LTL) or Computation Tree Logic (CTL) enables the use of formal verification tools such as model checkers. Nevertheless, formal languages require software developers to have a strong background in mathematics and logic.

The specification Patterns System (SPS) and Composite Propositions (CPs) use a higher-level abstraction to specify software properties formally. The SPS …

The Impact Of Cartel Related Violence On Ongoing Traumatic Stress And Self-Medication In Young Adults Living Along The U.S./México Border, Thom J. Taylor

Open Access Theses & Dissertations

Ongoing Potentially Traumatic Stress (OPTS) as a result of violence and insecurity along the U.S./México border remains understudied. Many residents of the border may be both indirectly and directly exposed to potentially traumatic events on an ongoing basis, particularly in the city of Cd. Juárez, México. The present study examined the impact of the violence and insecurity on daily traumatic stress levels and the potential for self-medication via alcohol, cigarettes, and illicit drugs within Spanish speaking young adult residents and commuters to Cd. Juárez, Chihuahua, México. Participants (N = 121) completed multiple online reports of location in and travel to …

A Comparison Of Computer-Based Training And Traditional Classroom Training For The Sad Corporation Job Placement Team, Janice Brown Adams

Dissertations

Purpose: The purpose of this research study was to compare the effectiveness of computer-based training with traditional classroom training; both instructional delivery methods utilized the traditional classroom curriculum as a means of delivery for an on-the-job company-sponsored program. The JAW-SAD Human Resource Center (HRC) is a training facility for the SAD Corporation, a major international manufacturing company. The HRC is responsible for conducting continuous training and certification of SAD employees. Historically, training has been provided through conference workshops with a traditional classroom training format. The motivation and importance for this study was influenced by an administrative requirement to determine the …

Forest Edge Effects On The Behavioral Ecology Of L'Hoest's Monkey (Cercopithecus Lhoesti) In Bwindi Impenetrable National Park, Uganda, Tharcisse Ukizintambara

Antioch University Dissertations & Theses

Forest edges are associated with forest edge effects that result from changes in physical features of the habitat, predator species and number, and prominence of human activities and other disturbances that can have direct or indirect impact on the distribution, ecology, and fitness of forest plant and animal species. I conducted a literature review on edge effects on primate species and came up with a classification of primate species in three general categories " thriving, sensitive and resilient species to edge effects " based on behavioral and demographic responses.

In Bwindi Impenetrable National Park, edge effects followed non-monotonic patterns (wave-like) …

Rare's Implementation Strategies Of Environmental Conservation In Indonesia, Alvaro Arvizo

Open Access Theses & Dissertations

Like most developing nations, Indonesia is at a crucial stage in its modern political and economic history. Opposing forces are constantly at work, a government struggling to make Indonesia a modern nation and the economic demands of a growing population. This presents the country with a multitude of problems. One of several is that nature's resources are exploited for personal economic gain with no regard for the long-term effects. This is a major concern for environmental conservation and non-profit government organizations (NGOs) worldwide. The American NGO Rare is at the forefront of this issue. Its aim is to meet community …

Bagc.M: Three Dimensional Gravity Modeling Software With An Application In Death Valley, Ca, Brian Eugene Eslick

Open Access Theses & Dissertations

Basin Anomaly Gravity Calculator (BAGC.m) is a 3D interactive gravity modeling package designed to create, edit, and calculate the gravitational attraction of basin models entirely within the MATLABTM environment. Gravity anomalies are calculated using the Rectangular Prism Method (Bott, 1960; Kane, 1962; and Plouff, 1966) which subdivides earth models into regularly spaced rectangular prisms. This approach requires large 3D matrices to store most realistic earth models. The process of model editing is simplified by storing basins as 2D gridded files which define the depth to the boundary between basement rock and sedimentary fill for each model cell. In order to …

Studies Of Earthquakes Stress Drops, Seismic Scattering, And Dynamic Triggering In North America, Christian Rene Escudero Ayala

Open Access Theses & Dissertations

I use the Relative Source Time Function (RSTF) method to determine the source properties of earthquakes within southeastern Alaska-northwestern Canada in a first part of the project, and earthquakes within the Denali fault in a second part. I deconvolve a small event P-arrival signal from a larger event by the following method: select arrivals with a tapered cosine window, fast fourier transform to obtain the spectrum, apply water level deconvolution technique, and bandpass filter before inverse transforming the result to obtain the RSTF. I compare the source processes of earthquakes within the area to determine stress drop differences to determine …

Renewable Energy Integration: An Approach For Micro-Grid Optimization., Nicolas Lopez

Open Access Theses & Dissertations

This thesis explores the Renewable Energy Integration Problem beginning with a literature review on the different sources of electrical energy classified as Non-Renewable and Renewable, stating that the integration of renewable sources within the pre-existing Power-Grids is a current worldwide problem that is being addressed with different approaches.

The impossibility to exactly model the different equations relating the electric output of the renewable energy sources as they relate with meteorological factors, makes the renewable sector a stochastic component of the overall mathematical model, where it can be concluded that most of the problem is in the area of the forecast. …

Investigations Of Grade Control, Macarthur Mine, Yerington, Nevada: An Oxidized Porphyry Copper System, Joseph Daniel Louis Lori

Open Access Theses & Dissertations

Supergene enriched, low-grade oxidized porphyry copper deposits are of great economic value. Oxidized porphyry sections are economic targets because even low-grade prospects have the potential to produce low-cost copper in an environmentally friendly fashion due to easy leachability and high recovery rates of the oxide mineralization. The MacArthur Mine, in the historic Yerington mining district of Nevada, is the focus of this study. The MacArthur is a tilted oxidized porphyry deposit, partially mined by open pit methods, hosted in the Jurassic Bear Quartz Monzonite of the Yerington batholith. The objective of the study is to define controls of copper oxide …

A Gis-Based Emission And Air Quality Impact Assessment For Evaluating Transportation Mitigation Measures, Jose Maria Mares

Open Access Theses & Dissertations

The research presented here develops a framework that assesses a transportation project's air quality impact. The framework not only integrates transportation and emission modeling but also improves the accuracy of the emission estimates. In order to do this, the framework makes use of six modules: environmental conditions data input, GIS database, emission modeling, transportation network, post-processing, and graphical presentation. Each module aims to improve the quality and accuracy of the inputs used by MOBILE6.2. In addition, the framework has the capability, among other features, of presenting the emission estimates in a GIS-based modeling platform that enables the analyst to spatially …

Coordination Directed Self Assembly Of Pt/Pd Mono-And Multinuclear Complexes, Robert Moreno

Open Access Theses & Dissertations

This research focuses on the development of mononuclear platinum complexes; multinuclear platinum complexes, both of which self assemble into micelles in the presence of water. This work also involved the synthesis of a reverse micelle that allows for detection of water nanocrystals within a defined size molecular envelope. The novel synthesis of these compounds allows for ligand substitution and the creation of a library of compounds.

Copper Isotope Fractionation During Surface Adsorption And Intracellular Incorporation By Bacteria, Jesica Urbina Navarrete

Open Access Theses & Dissertations

Copper isotopes may prove to be a useful tool for investigating bacteria-metal interactions recorded in natural waters, soils, and rocks. However, experimental data that constrain Cu isotope fractionation in biologic systems are limited and unclear. In this study we utilized Cu isotopes (65Cu) as a tool to investigate Cu-bacteria interactions, including surface adsorption and intracellular incorporation. Experiments were conducted with individual Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli) bacterial species as well as with bacterial consortia from several natural environments. Adsorption experiments were conducted with live or dead cells over the pH range 2.5 to 6. Surface adsorption of Cu …

Study Of Pbdes In Wastewater, Water And Sludge Of El Paso Del Norte Border Region Using Sbse Td/Gc-Ms, Beatriz Adriana Rocha-Gutierrez

Open Access Theses & Dissertations

Polybrominated diphenyl ethers (PBDEs) are a group of brominated compounds widely used as flame retardants. PBDEs are structurally similar to polychlorinated biphenyls (PCBs), and appear to act similarly in the environment. Due to their persistence and lipophilicity, PBDEs are found to be bioaccumulated and biomagnified in the food chain. Current research in PBDEs is focused on their occurrences, concentration, fate and transport in the environment, and the impact in the ecosystem and human health. Since PBDEs are not regulated in the USA, large amounts of these harmful chemicals are being dumped indiscriminately into the drainage system. As a result, these …

A Deadline-Driven Epidemic Data Collection Protocol Suitable For Tracking Interpersonnel Rendezvous, Avranil Tah

Open Access Theses & Dissertations

This thesis describes a peer-to-peer wireless data collection algorithm that uses epidemic communication to propagate time-sensitive sequentially sampled data records from sensors toward infrastructure connected upload stations via mobile data mules. These records are labeled with sequence numbers and delivery deadlines, and are transmitted in sequential order. Delivery deadlines enable transmission prioritization and trigger alarms warning of violations.

The sequential ordering of records simplifies the protocols transmission-control and garbage collection mechanisms: only two monotonically increasing scalar sequence indices associated with a particular sensor must be exchanged between peers prior to selecting which records need to be communicated. One of these …

Seismic Investigation Of The Southern Rio Grande Rift, Lennox Emmanuel Thompson

Open Access Theses & Dissertations

Competing models exist to explain what caused the Earth's crust to spread apart 29 million years ago to create a region known today as the Rio Grande Rift (RGR). The RGR extends from central Colorado through New Mexico to northern Mexico, near El Paso. The RGR has different geologic features that distinguish it from most other valleys (e.g., the RGR was not cut by a river nor does a river branch upstream). A growing body of evidence shows that geologic activity still occurs in the RGR, with a continuation of faulting, seismicity and widening at a small rate of about …

Preliminary Archaeological Investigations At The Sierra Diablo Cave Site: Paleoindian And Archaic Occupations In Hudspeth County, Texas, Jose Javier Vasquez

Open Access Theses & Dissertations

It is generally rare to find archaeological sites in the Southwest that retain the type of contextual integrity that the Sierra Diablo Cave exhibits. Often times, cave sites such as the one currently studied offer excellent preservation of cultural materials due to the general lack of moisture and isolation from wind and water erosion. The research aimed to determine when the site was occupied as well as the types of activities that were occurring during those occupations. It exhibits an extensive stratigraphic sequence that contains a well pronounced Late Archaic Period assemblage (Strata A and B) and a Late Pleistocene/Early …

Synthesis And Manufacture Of Photocrosslinkable Poly(Caprolactone)-Based 3d Scaffolds For Tissue Engineering Applications, Nathan Jonathan Castro

Open Access Theses & Dissertations

It is known that the body can efficiently repair hard tissue (bone) micro fractures by suturing the defect through the deposition of minerals resulting in an area that is stronger post-injury. Larger defects, however, generally cause more trouble since the body is incapable of repairing them. Bone defects can occur as a result of congenital abnormalities, trauma, or disease. Traditional methods for addressing these defects have involved the use of acellular cadaverous bone or autologous bone. Both contain innate problems associated with them; the former method can result in disease transmission, as well as very low integration with the host …

Pressure Induced Dynamical Instabilities In Body Center Cubic Crystals, Oscar Guerrero

Open Access Theses & Dissertations

Large-scale atomistic simulations of shock-wave propagation in single crystals exhibit large anisotropies in the elastic-plastic and solid-liquid transitions. Characteristic of this type of simulations are the large strains at which the crystal yields plastically, regardless of crystal orientation. At these large strains, uniaxial deformations, such as those produced in planar shock loading generate dynamical instabilities. We have investigated the directional anisotropy of the elastic limit in bcc crystals, in particular Tantalum (Ta), employing molecular dynamics (MD) simulations. We show that the elastic - plastic transition in BCC defect-free crystals is caused by the appearance of soft-phonon modes and not via …

Development Of Wide Band Gap Semiconductor Materials For Renewable Energy, S.M. Sarif Masud

Open Access Theses & Dissertations

Several new wide band gap semiconductor nanocomposite photocatalytic materials have been synthesized from HTiNbO5 and HNb3O8 for solar energy conversion. As a source of renewable energy, the materials are being tested to produce hydrogen fuel from water via photolysis. The materials have high surface areas, are macroporous, and have flatband potentials suitable for reducing water to create hydrogen. Under visible or ultra violet light, the materials were found to be very promising as hydrogen evolving photocatalysts. As part of the synthesis of the composites, the catalysts also exhibited excellent catalytic activity under UV light for reducing ionic platinum and gold …

Structural And Electronic Properties Of Aluminum Nano Clusters By Dft, Mrudula Raparla

Open Access Theses & Dissertations

The electronic properties of Al clusters containing up to 60 atoms are investigated using an all electron density functional theory using large polarized Gaussian basis sets with 39 Gaussians per atom (NRLMOL basis). We have performed an extensive search for the lowest energy isomers for clusters up to Al 21. We build a database of candidate structures for the ground state using different strategies. First, a few structures are randomly generated and fully relaxed using plane wave pseudo potential method. We also performed simulated annealing runs using ab initio molecular dynamics for clusters up to Al20. In three sets of …

Physical And Biochemical Assessment Of Mexican Palo Verde Response To Chromium Toxicity, Yong Zhao

Open Access Theses & Dissertations

In the United States, about 1/3 of the 1400 superfund sites have been reported to be chromium contaminated, making chromium the second most common metal found in superfund chemical contamination sites. Chromium removal from soil has commonly been carried out via chemical, physical, and thermal processes. However, these methods are expensive and/or invasive to local ecosystems. In contrast to these techniques, phytoremediation (the use of plants to remove toxic substances from areas containing contamination at low or medium levels) appears to be a cost-effective and environmentally friendly process for chromium removal. However, most reports on chromium phytoremediation suggest that this …

Database Security: What Students Need To Know, Meg C. Murray

Faculty Articles

Database security is a growing concern evidenced by an increase in the number of reported incidents of loss of or unauthorized exposure to sensitive data. As the amount of data collected, retained and shared electronically expands, so does the need to understand database security. The Defense Information Systems Agency of the US Department of Defense (2004), in its Database Security Technical Implementation Guide, states that database security should provide controlled, protected access to the contents of a database as well as preserve the integrity, consistency, and overall quality of the data. Students in the computing disciplines must develop an …

A Systematic Study Of The Dispersion Of Swnts In Organic Solvents, Qiaohuan Cheng, Sourabhi Debnath, Luke O'Neill, Theresa Hedderman, Elizabeth Gregan

Articles

Dispersions of as-produced HiPco single-walled carbon nanotubes (SWNTs) in a series of organic solvents were prepared by dilution with the aid of tip sonication. Mild centrifugation (945 g) was carried out to remove large bundles. Atomic force microscopy (AFM) studies revealed that the bundle size decreased as the dispersion was diluted. By measuring the UV−vis−NIR absorption before and after centrifugation as a function of the concentration, the dispersion limit of SWNTs in each solvent can be determined. Correlations between the dispersion limit and solvent solubility parameters, including the Hildebrand solubility parameter and three-dimensional Hansen solubility parameters, are explored, demonstrating that …

Sonolytic Degradation Of Parathion And The Formation Of Byproducts, Juan Juan Yao, Nai Yun Gao, Yang Deng, Yan Ma, Hai Jun Li, Bin Xu, Lei Li

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Ultrasonic degradation of parathion has been investigated in this study. At a neutral condition, 99.7% of 2.9 μM parathion could be decomposed within 30 min under 600 kHz ultrasonic irradiation at ultrasonic intensity of 0.69 W/cm2. The degradation rate increased proportionally with the increasing ultrasonic intensity from 0.10 to 0.69 W/cm2. The parathion degradation was enhanced in the presence of dissolved oxygen due to formation of more {radical dot}OH, but was inhibited in the presence of nitrogen gas owning to the free radical scavenging effect in vapor phase within the cavitational bubbles. CO32 -, HCO3-, and Cl- exhibited the inhibiting …

E-Carrel: An Environment For Collaborative Textual Scholarship, George K. Thiruvathukal, Steven E. Jones, Peter Shillingsburg

Computer Science: Faculty Publications and Other Works

The E-Carrel project aims to address the preservation of, access to, and re-uses of humanities electronic text files. It enables dynamic, growing resource projects as repositories for new knowledge. It provides for on-line distributed data and tools that are open to new scholarly enhancement through a user friendly tagging tool, sophisticated use of stand-off markup and annotation (leveraging RDF capabilities), and a browsing system anyone can use. It creates a secure system of text preparation and dissemination that encourages collaboration and participation by anyone interested in the texts. To insure the endurance of authenticated texts, multiple copies are distributed on …

Computer-Guided Solutions To Physics Problems Using Prolog, Thomas J. Bensky, Catherine A. Taff

Physics

By posing a continual stream of pertinent questions, a nonmathematical computer program can prod freshman physics students toward an analytical solution to one-dimensional kinematics problems.