Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

2012

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 1051 - 1080 of 12196

Full-Text Articles in Physical Sciences and Mathematics

Nabla Fractional Calculus And Its Application In Analyzing Tumor Growth Of Cancer, Fang Wu Dec 2012

Nabla Fractional Calculus And Its Application In Analyzing Tumor Growth Of Cancer, Fang Wu

Masters Theses & Specialist Projects

This thesis consists of six chapters. In the first chapter, we review some basic definitions and concepts of fractional calculus. Then we introduce fractional difference equations involving the Riemann-Liouville operator of real number order between zero and one. In the second chapter, we apply the Brouwer fixed point and Contraction Mapping Theorems to prove that there exists a solution for up to the first order nabla fractional difference equation with an initial condition. In chapter three, we define a lower and an upper solution for up to the first order nabla fractional difference equation with an initial condition. Under certain …


Estimating Software Effort Using An Ann Model Based On Use Case Points, Ali Bou Nassif, Luiz Fernando Capretz, Danny Ho Dec 2012

Estimating Software Effort Using An Ann Model Based On Use Case Points, Ali Bou Nassif, Luiz Fernando Capretz, Danny Ho

Electrical and Computer Engineering Publications

In this paper, we propose a novel Artificial Neural Network (ANN) to predict software effort from use case diagrams based on the Use Case Point (UCP) model. The inputs of this model are software size, productivity and complexity, while the output is the predicted software effort. A multiple linear regression model with three independent variables (same inputs of the ANN) and one dependent variable (effort) is also introduced. Our data repository contains 240 data points in which, 214 are industrial and 26 are educational projects. Both the regression and ANN models were trained using 168 data points and tested using …


An Affordance-Based Framework For Human Computation And Human-Computer Collaboration, R. Jordan Crouser, Remco Chang Dec 2012

An Affordance-Based Framework For Human Computation And Human-Computer Collaboration, R. Jordan Crouser, Remco Chang

Computer Science: Faculty Publications

Visual Analytics is “the science of analytical reasoning facilitated by visual interactive interfaces” [70]. The goal of this field is to develop tools and methodologies for approaching problems whose size and complexity render them intractable without the close coupling of both human and machine analysis. Researchers have explored this coupling in many venues: VAST, Vis, InfoVis, CHI, KDD, IUI, and more. While there have been myriad promising examples of human-computer collaboration, there exists no common language for comparing systems or describing the benefits afforded by designing for such collaboration. We argue that this area would benefit significantly from consensus about …


Using Variable-Rate Alerting To Counter Boredom In Human Supervisory Control, Armen A. Mkrtchyan, Jamie C. Macbeth, Erin T. Solovey, Jason C. Ryan, M. L. Cummings Dec 2012

Using Variable-Rate Alerting To Counter Boredom In Human Supervisory Control, Armen A. Mkrtchyan, Jamie C. Macbeth, Erin T. Solovey, Jason C. Ryan, M. L. Cummings

Computer Science: Faculty Publications

A low task load, long duration experiment was conducted to evaluate the impact of cyclical attention switching strategies on operator performance in supervisory domains. The impetus for such a study stems from the lack of prior work to improve human-system performance in low task load supervisory domains through the use of design interventions. In this study, a design intervention in the form of auditory alerts is introduced and the effects of the alerts are examined. The test bed consists of a video game-like simulation environment, which allows a single opera-tor the ability to supervise multiple unmanned vehicles. Each participant in …


Interface Design For Unmanned Vehicle Supervision Through Hybrid Cognitive Task Analysis, Jamie C. Macbeth, M. L. Cummings, Luca F. Bertuccelli, Amit Surana Dec 2012

Interface Design For Unmanned Vehicle Supervision Through Hybrid Cognitive Task Analysis, Jamie C. Macbeth, M. L. Cummings, Luca F. Bertuccelli, Amit Surana

Computer Science: Faculty Publications

While there is currently significant interest in developing Unmanned Aerial Systems (UASs) that can be supervised by a single operator, the majority of these systems focus on Intelligence, Surveillance, and Reconnaissance (ISR) domains. One domain that has received significantly less attention is the use of multiple UASs to insert or extract supplies or people. To this end, MAVIES (Multi-Autonomous Vehicle Insertion-Extraction System) was developed to allow a single operator the ability to supervise a primary cargo Unmanned Aerial Vehicle (UAV) along with multiple scouting UAVs. This paper will detail the development of the design requirements generated through a Hybrid Cognitive …


Query Plan Execution In A Heterogeneous Stream Management System For Situational Awareness, Indrakshi Ray, Sanjay K. Madria, Mark Linderman Dec 2012

Query Plan Execution In A Heterogeneous Stream Management System For Situational Awareness, Indrakshi Ray, Sanjay K. Madria, Mark Linderman

Computer Science Faculty Research & Creative Works

Battlefield monitoring involves collecting streaming data from different sources, transmitting the data over a heterogeneous network, and processing queries in real-time in order to respond to events in a timely manner. Nodes in these networks differ with respect to their processing, storage and communication capabilities. Links in the network differ with respect to their communication bandwidth. the topology of the network itself is subject to change, as the nodes and links may become unavailable. Continuous queries executed in such environments must also meet some quality of service (QoS) requirements, such as, response time, throughput, and memory usage. We propose that …


Securing A Wireless Networked Control System Using Information Fusion, Brijesh Kashyap Chejerla, Sanjay Madria Dec 2012

Securing A Wireless Networked Control System Using Information Fusion, Brijesh Kashyap Chejerla, Sanjay Madria

Computer Science Faculty Research & Creative Works

Security of a wireless sensor network practically governs its usability in several applications. Especially, in applications like Industrial control systems which use NCS and SCADA systems, the security affects the stability of the system. We propose to use an information fusion scheme which allows us to profile the different attacks in wireless sensor networks and study their effects on the control systems stability and feedback. We make use of the Bayesian Networks to obtain hypotheses as outputs which form the decisions. These decisions are made based on the feature extraction and estimation process of the entire information fusion scheme. This …


Incentive Based Approach To Find Selfish Nodes In Mobile P2p Networks, Hemanth Meka, Sanjay K. Madria, Mark Linderman Dec 2012

Incentive Based Approach To Find Selfish Nodes In Mobile P2p Networks, Hemanth Meka, Sanjay K. Madria, Mark Linderman

Computer Science Faculty Research & Creative Works

In a Mobile P2P (M-P2P) network, selfish nodes can drop packets to affect the efficiency of the whole network. Therefore, we propose a simple and efficient mechanism using virtual currency to identify selfish nodes in the network. Each node issues a receipt to its broker to prove that it has provided a forwarding service. based on receipts received each broker provides well-behaved nodes some virtual currency whereas selfish nodes are punished on dropping packets to make the network more efficient. When compared to other known approaches, our scheme provides real-time detection of selfish nodes and does not require/assume the presence …


Search-Based Detection Of High-Level Model Changes, Ameni Ben Fadhel, Marouane Kessentini, Philip Langer, Manuel Wimmer Dec 2012

Search-Based Detection Of High-Level Model Changes, Ameni Ben Fadhel, Marouane Kessentini, Philip Langer, Manuel Wimmer

Computer Science Faculty Research & Creative Works

Software models are iteratively refined, restructured and evolved. the detection and analysis of changes applied between two versions of a model are one of the most important tasks during evolution and maintenance activities. in this paper, we propose an approach to detect high-level model changes in terms of refactoring. Our approach takes as input an exhaustive list of possible refactoring, the initial model and revised model, and generates as output a list of detected changes representing a sequence of refactoring. a solution is defined as a combination of refactoring that should maximize as much as possible the similarity between the …


Structural And Message Based Private Friend Recommendation, Bharath K. Samanthula, Wei Jiang Dec 2012

Structural And Message Based Private Friend Recommendation, Bharath K. Samanthula, Wei Jiang

Computer Science Faculty Research & Creative Works

The emerging growth of online social networks have opened new doors for various business applications such as promoting a new product across its customers. Besides this, friend recommendation is an important tool for recommending potential candidates as friends to users in order to enhance the development of the entire network structure. Existing friend recommendation methods utilize social network structure and/or user profile information. However, these techniques can no longer be applicable if the privacy of users is taken into consideration. in this paper, we propose a two-phase private friend recommendation protocol for recommending friends to a given target user based …


Lagrangian Relaxation For Large-Scale Multi-Agent Planning, Geoffrey J. Gordon, Pradeep Varakantham, William Yeoh, Hoong Chuin Lau, Ajay S. Aravamudhan, Shih-Fen Cheng Dec 2012

Lagrangian Relaxation For Large-Scale Multi-Agent Planning, Geoffrey J. Gordon, Pradeep Varakantham, William Yeoh, Hoong Chuin Lau, Ajay S. Aravamudhan, Shih-Fen Cheng

Research Collection School Of Computing and Information Systems

Multi-agent planning is a well-studied problem with various applications including disaster rescue, urban transportation and logistics, both for autonomous agents and for decision support to humans. Due to computational constraints, existing research typically focuses on one of two scenarios: unstructured domains with many agents where we are content with heuristic solutions, or domains with small numbers of agents or special structure where we can provide provably near-optimal solutions. By contrast, in this paper, we focus on providing provably near-optimal solutions for domains with large numbers of agents, by exploiting a common domain-general property: if individual agents each have limited influence …


Protein Nano-Object Integrator (Pronoi) For Generating Atomic Style Objects For Molecular Modeling, Nicholas Smith, Brandon Campbell, Lin Li, Chuan Li, Emil Alexov Dec 2012

Protein Nano-Object Integrator (Pronoi) For Generating Atomic Style Objects For Molecular Modeling, Nicholas Smith, Brandon Campbell, Lin Li, Chuan Li, Emil Alexov

Publications

Background

With the progress of nanotechnology, one frequently has to model biological macromolecules simultaneously with nano-objects. However, the atomic structures of the nano objects are typically not available or they are solid state entities. Because of that, the researchers have to investigate such nano systems by generating models of the nano objects in a manner that the existing software be able to carry the simulations. In addition, it should allow generating composite objects with complex shape by combining basic geometrical figures and embedding biological macromolecules within the system.

Results

Here we report the Protein Nano-Object Integrator (ProNOI) which allows for …


Multi-Color Observations Of Short Grb Afterglows: 20 Events Observed Between 2007 And 2010, A. Nicuesa Guelbenzu, S. Klose, J. Greiner, D. A. Kann, T. Krühler, A. Rossi, S. Schulze, P. M. J. Afonso, J. Elliott, R Filgas, Dieter H. Hartmann, A Kupcu Yoldas, S Mcbreen, M Nardini, F Olivares E., A Rau, S Schmidl, P Schady, V Sudilovsky, A C. Updike, A Yoldas Dec 2012

Multi-Color Observations Of Short Grb Afterglows: 20 Events Observed Between 2007 And 2010, A. Nicuesa Guelbenzu, S. Klose, J. Greiner, D. A. Kann, T. Krühler, A. Rossi, S. Schulze, P. M. J. Afonso, J. Elliott, R Filgas, Dieter H. Hartmann, A Kupcu Yoldas, S Mcbreen, M Nardini, F Olivares E., A Rau, S Schmidl, P Schady, V Sudilovsky, A C. Updike, A Yoldas

Publications

We report on follow-up observations of 20 short-duration gamma-ray bursts (GRBs; T90 <2 >s) performed in g'r'i'z' JHKs with the Gamma-Ray Burst Optical Near-Infrared Detector (GROND) between mid-2007 and the end of 2010. This is one of the most compre-hensive data sets on GRB afterglow observations of short bursts published so far. In three cases, GROND was on target within less than 10 min after the trigger, leading to the discovery of the afterglow of GRB 081226A and its faint underlying host galaxy. In addition, GROND was able to image the optical afterglow and follow the light curve evolution in five …


Objective Bayesian Inference On The Common Mean Of Normal Distributions, Shiyi Tu Dec 2012

Objective Bayesian Inference On The Common Mean Of Normal Distributions, Shiyi Tu

All Theses

One of the oldest problems in statistical area is to make inference on a common mean of several different normal populations with unknown and probably unequal variances. There are several different ways to make inference on the common mean. The most common methods are point estimation, hypothesis testing, and interval estimation. Point estimation uses sample data to calculate a single value serving as a best guess for the unknown population mean. Hypothesis testing assumes all populations have the same mean as the null hypothesis. Interval estimation is an interval of possible values of the unknown mean.
In this paper, we …


Assessing Allelopathic Effects Of Alexandrium Fundyense On Thalassiosira Sp., Emily R. Lyczkowski Dec 2012

Assessing Allelopathic Effects Of Alexandrium Fundyense On Thalassiosira Sp., Emily R. Lyczkowski

Electronic Theses and Dissertations

Production of allelopathic chemicals by the toxic dinoflagellate Alexandrium fundyense is one suggested mechanism by which this relatively slow grower outcompetes other phytoplankton, particularly diatoms. Despite well documented allelopathic potential of Alexandrium spp., the potency is variable. To further characterize allelopathic effects of A. fundyense on diatoms in the Gulf of Maine, I studied growth and nutrient acquisition by the chain-forming diatom Thalassiosira sp. in the presence and absence of allelochemicals. Thalassiosira cells, upon exposure to filtrate of A. fundyense cultures exhibited “bleaching” and both growth and nutrient utilization ceased for up to 4 days compared to controls. Results from …


Synthesis And Characterizations Of Pyridinium Salts Including Poly(Pyridinium Salt)S And Their Applications, Tae Soo Jo Dec 2012

Synthesis And Characterizations Of Pyridinium Salts Including Poly(Pyridinium Salt)S And Their Applications, Tae Soo Jo

UNLV Theses, Dissertations, Professional Papers, and Capstones

Pyridinium salts, both molecular and polymeric, are an interesting class of multifunctional materials that exhibit liquid-crystalline and light-emitting properties. Moreover, their properties can be easily tuned by introducing new types of anions or by modifying their chemical structures. This dissertation describes synthesis and characterization of poly(pyridinium salt)s containing macrocounterions and fluorene moieties in their backbones, synthesis and characterization of nanocomposites of poly(pyridinium salt)s with single-walled carbon nanotubes via non-covalent interactions, and synthesis and characterizations of pyridinium salts having different aliphatic linkages and their application in organic acid sensing.

First, all of these ionic polymers were prepared by either ring-transmutation or …


Safe: Simulation Automation Framework For Experiments, Luiz Felipe Perrone, Bryan C. Ward, Christopher S. Main Dec 2012

Safe: Simulation Automation Framework For Experiments, Luiz Felipe Perrone, Bryan C. Ward, Christopher S. Main

Faculty Journal Articles

The workflow of a network simulation study requires adherence to best practices in methodology so that results are credible and reproducible by third parties. The opportunities for one to introduce errors start at model description and permeate the process through to the reporting of results. The literature indicates that even publications in respected venues include inadvertent mistakes and poor application of methodology. When experts are liable to fail, it is unreasonable to expect that students would fare any better. This paper presents a system designed to provide guidance for inexperienced users of the popular ns-3 network simulator. SAFE automates the …


Rickettsia Felis In Cat Fleas, Ctenocephalides Felis Parasitizing Opossums, San Bernardino County, California, Kyle F. Abramowicz, J. W. Wekesa, C. N. Nwadike, Maria L. Zambrano, Sandor E. Karpathy, D. Cecil, J. Burns, R. Hu, Marina E. Eremeeva Dec 2012

Rickettsia Felis In Cat Fleas, Ctenocephalides Felis Parasitizing Opossums, San Bernardino County, California, Kyle F. Abramowicz, J. W. Wekesa, C. N. Nwadike, Maria L. Zambrano, Sandor E. Karpathy, D. Cecil, J. Burns, R. Hu, Marina E. Eremeeva

Environmental Health Sciences Faculty Publications

Los Angeles and Orange Counties are known endemic areas for murine typhus in California; however, no recent reports of flea-borne rickettsioses are known from adjacent San Bernardino County. Sixty-five opossums (Didelphis virginiana) were trapped in the suburban residential and industrial zones of the southwestern part of San Bernardino County in 2007. Sixty out of 65 opossums were infested with fleas, primarily cat fleas, Ctenocephalides felis (Bouché, 1835). The flea minimum infection rate with Rickettsia felis was 13.3% in pooled samples and the prevalence was 23.7% in single fleas, with two gltA genotypes detected. In spite of historic records of murine …


Economic Impacts Of The Kentucky Green Industry, Dewayne L. Ingram, Alan Hodges Dec 2012

Economic Impacts Of The Kentucky Green Industry, Dewayne L. Ingram, Alan Hodges

Agriculture and Natural Resources Publications

The Green Industry has a significant impact on Kentucky’s economy. Green Industry enterprise owners, managers and employees should be aware of their economic impacts, and policy makers and other state leaders need to know the importance of this industry as potential laws, regulations and resource allocations are considered. This publication is intended to provide a brief summary of the 2007 economic impacts of the Green Industry in Kentucky.


Limited Sampling Estimates Of Epigallocatechin Gallate Exposures In Cirrhotic And Noncirrhotic Patients With Hepatitis C After Single Oral Doses Of Green Tea Extract., Dina Halegoua-De Marzio, Walter K. Kraft, Constantine Daskalakis, Xie Ying, Roy L Hawke, Victor J. Navarro Dec 2012

Limited Sampling Estimates Of Epigallocatechin Gallate Exposures In Cirrhotic And Noncirrhotic Patients With Hepatitis C After Single Oral Doses Of Green Tea Extract., Dina Halegoua-De Marzio, Walter K. Kraft, Constantine Daskalakis, Xie Ying, Roy L Hawke, Victor J. Navarro

Division of Gastroenterology and Hepatology Faculty Papers

BACKGROUND: Epigallocatechin-3-gallate (EGCG) has antiangiogenic, antioxidant, and antifibrotic properties that may have therapeutic potential for the treatment of cirrhosis induced by hepatitis C virus (HCV). However, cirrhosis might affect EGCG disposition and augment its reported dose-dependent hepatotoxic potential.

OBJECTIVE: The safety, tolerability, and disposition of a single oral dose of EGCG in cirrhotic patients with HCV were examined in an exploratory fashion.

METHODS: Eleven patients with hepatitis C and detectable viremia were enrolled. Four had Child-Pugh (CP) class A cirrhosis, 4 had Child-Pugh class B cirrhosis, and 3 were noncirrhotic. After a single oral dose of green tea extract 400 …


Dynamic Data Race Detection And Healing, Du Li Dec 2012

Dynamic Data Race Detection And Healing, Du Li

Department of Computer Science and Engineering: Dissertations, Theses, and Student Research

Perpetual availability is an important operational goal in today's computer systems. However, achieving this goal is challenging because modern software systems contain faults that can cause them to fail. For example, multi-threading is widely used in modern software to fully utilize the computing capability of multicore processors. However, employing multi-threading can lead to concurrency faults such as deadlock and data race that are notoriously difficult to to isolate, detect, and repair.Data races, which involves two concurrent accesses to the same data where at least one is a write, are the most common concurrency faults.

As our first step, we investigate …


Communication Of Recycling Through Labeling And Packaging, Serena Mistry Dec 2012

Communication Of Recycling Through Labeling And Packaging, Serena Mistry

Graphic Communication

Recycling has become a more prevalent practice in the last few decades. However, the labeling system on today’s packaging is not always clear in indicating whether something is recyclable. Recently, there has been a great deal of attention directed at a new system, known as the How2Recycle label, an innovative labeling system expected to launch in the next few years. As the population continues to grow at unprecedented levels and more strain is placed on the global environment, recycling becomes more crucial. In the United States, the lack of a standard system for recycling on labeling and packaging deters people …


The Harmonica As A Blues Instrument, Gordon Ramsey, Christopher Banaszak, Joseph Wiseman Dec 2012

The Harmonica As A Blues Instrument, Gordon Ramsey, Christopher Banaszak, Joseph Wiseman

Physics: Faculty Publications and Other Works

The modern harmonica,or harp, has been around since the early 19th century. It is typically used in blues, country, rock and roll and folk music. These musical genres are somewhat similar in structure and form, and often borrow ideas from each other. The harmonica is appropriate as a back up to the main vocal melody and instruments due to its rich harmonic structure and subdued intensity. The ability to apply vibrato and gradual slurs make it a perfect instrument to achieve a ``bluesy" sound. Our harp research group has investigated the physical properties of harmonica structure to illustrate how different …


Synthesis And Biological Activity Of Aminoglycosides And 1,4-Naphthoquinone Derivatives, Marina Fosso Yatchang Dec 2012

Synthesis And Biological Activity Of Aminoglycosides And 1,4-Naphthoquinone Derivatives, Marina Fosso Yatchang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The research described in this dissertation is at the interface of organic chemistry and biology, and it aimed at designing and synthesizing biologically active molecules for the possible development of therapeutic agents.

Spinal muscular atrophy is an incurable disease that affects 1 in every 6000 babies, making it the leading genetic cause of infant mortality. While no treatment is available, efforts are being taken to solve this issue. Part of the work outlined in this dissertation was carried out in collaboration with researchers from the University of Missouri to investigate a potential therapeutic for this disease.

In addition, the continuous …


Modeling Lithospheric Rheology From Modern Measurements Of Bonneville Shoreline Deformation, Eric P. Beard Dec 2012

Modeling Lithospheric Rheology From Modern Measurements Of Bonneville Shoreline Deformation, Eric P. Beard

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Here I develop a new method for estimating differences in elevation between pairs of paleo-lake shoreline features. This method is applied to Lake Bonneville, a large lake that inundated nearly 1/3 of the state of Utah as well as parts of Nevada and Idaho from 34 to 11.5 thousand years ago. Under the weight of the lake water load, the surface of the Earth was depressed by up to 75 m. This occurred as Earth mantle rock at depth flowed outward in response to the weight of the lake. I use this new methodology to compile here a denser sample …


Stress-Lifetime Joint Distribution Model For Performance Degradation Failure, Quan Sun, Yanzhen Tang, Jing Feng, Paul Kvam Dec 2012

Stress-Lifetime Joint Distribution Model For Performance Degradation Failure, Quan Sun, Yanzhen Tang, Jing Feng, Paul Kvam

Department of Math & Statistics Faculty Publications

The high energy density self-healing metallized film pulse capacitor has been applied to all kinds of laser facilities for their power conditioning systems under several stress levels, such as 23kV, 30kV and 35kV, whose reliability performance and maintenance costs are affected by the reliability of capacitors. Due to the costs and time restriction, how to assess the reliability of highly reliable capacitors under a certain stress level as soon as possible becomes a challenge. Accelerated degradation test provides a way to predict its lifetime and reliability effectively. A model called stress-lifetime joint distribution model and an analysis method based on …


Scientific Basis For Safely Shutting In The Macondo Well After The April 20, 2010 Deepwater Horizon Blowout, Stephen H. Hickman, Paul A. Hsieh, Walter D. Mooney, Catherine B. Enomoto, Philip H. Nelson, Larry A. Mayer, Thomas C. Weber, Kathryn Moran, P. B. Flemings, Marcia Mcnutt Dec 2012

Scientific Basis For Safely Shutting In The Macondo Well After The April 20, 2010 Deepwater Horizon Blowout, Stephen H. Hickman, Paul A. Hsieh, Walter D. Mooney, Catherine B. Enomoto, Philip H. Nelson, Larry A. Mayer, Thomas C. Weber, Kathryn Moran, P. B. Flemings, Marcia Mcnutt

Center for Coastal and Ocean Mapping

As part of the government response to the Deepwater Horizon blowout, a Well Integrity Team evaluated the geologic hazards of shutting in the Macondo Well at the seafloor and determined the conditions under which it could safely be undertaken. Of particular concern was the possibility that, under the anticipated high shut-in pressures, oil could leak out of the well casing below the seafloor. Such a leak could lead to new geologic pathways for hydrocarbon release to the Gulf of Mexico. Evaluating this hazard required analyses of 2D and 3D seismic surveys, seafloor bathymetry, sediment properties, geophysical well logs, and drilling …


Fate And Reactivity Of Natural And Manufactured Nanoparticles In Soil/Water Environments, Allison Vandevoort Dec 2012

Fate And Reactivity Of Natural And Manufactured Nanoparticles In Soil/Water Environments, Allison Vandevoort

All Dissertations

Nanoparticles (NPs), < 100 nm in diameter, make up the smallest component of solid material. This small size often causes increased reactivity in soil/water environments, which is true for both natural NPs, such as very fine clay particles, and for manufactured nanoparticles, such as silver nanoparticles (AgNPs). As the importance of these particles is more widely recognized, and as manufactured nanoparticles, especially AgNPs, are increasing in production, it is essential to consider their effect on terrestrial and aquatic environments. The studies presented in this dissertation show that both the physicochemical characteristics of the NPs (e.g., particle size, surface coating, elemental composition), as well as soil-water interfacial chemistry (e.g., ionic strength, ligand concentration, pH), are instrumental in predicting environmental fate and reactivity.
Ligand type and concentration were especially important in NP reactivity and bioavailability. Using the hard/soft acid/base concept, the effect of phosphate ligand (hard base) on Fe/Al (hard acid) oxyhydroxide natural NPs was investigated in Chapters 2 and 3. Adding phosphate to soil NPs and reference nano-minerals (Fe-(oxyhydr)oxides and kaolinite) caused coagulation or dispersion, changing the particle size of the NPs, as well as affecting the amount of phosphate in its bioavailable (i.e., dissolved) form. A review of the literature in Chapters 1 and 3 revealed that changes in the soil conditions, and therefore, soil colloids/NPs (e.g., increasing organic …


Spectroscopic Signature For Bundling, Edge States And Impurities In 1d And 0d Materials, Kiran Kumar Lingam Dec 2012

Spectroscopic Signature For Bundling, Edge States And Impurities In 1d And 0d Materials, Kiran Kumar Lingam

All Dissertations

Study of nanomaterials has gained interest of researchers from various fields of science and technology due to their unique electronic and vibrational properties as compared to their bulk counterparts. In particular, carbon nanotechnology has evolved rapidly over the past few decades and nowadays, carbon nanotubes are used in various fields such as energy storage, electronics etc. However, the quest for new properties of this material is never ending and the invention of graphene generated enormous interest in the scientific community due to its excellent properties such as strength, high electron mobility, thermal conductivity etc. In this thesis, I aim at …


Asymptotics For The Arc Length Of A Multivariate Time Series And Its Applications As A Measure Of Risk, Tharanga Wickramarachchi Dec 2012

Asymptotics For The Arc Length Of A Multivariate Time Series And Its Applications As A Measure Of Risk, Tharanga Wickramarachchi

All Dissertations

The necessity of more trustworthy methods for measuring the risk (volatility) of financial assets has come to the surface with the global market downturn This dissertation aims to propose sample arc length of a time series, which provides a measure of the overall magnitude of the one-step-ahead changes over the observation time period, as a new approach for quantifying the risk. The Gaussian functional central limit theorem is proven under finite second moment conditions. Without loss of generality we consider equally spaced time series when first differences of the series follow a variety of popular stationary models including autoregressive moving …