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2009

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Articles 6301 - 6330 of 6353

Full-Text Articles in Physical Sciences and Mathematics

Benefit Cost Scenarios Of Potential Oral Rabies Vaccination For Skunks In California, Stephanie A. Shwiff, Ray T. Sterner, Robert Hale, Michele T. Jay, Ben Sun, Dennis Slate Jan 2009

Benefit Cost Scenarios Of Potential Oral Rabies Vaccination For Skunks In California, Stephanie A. Shwiff, Ray T. Sterner, Robert Hale, Michele T. Jay, Ben Sun, Dennis Slate

United States Department of Agriculture Wildlife Services: Staff Publications

Scenario-based analyses were computed for benefits and costs linked with hypothetical oral rabies vaccination (ORV) campaigns to contain or eliminate skunk-variant rabies in skunks (Mephitis mephitis) in California, USA. Scenario 1 assumed baiting eight zones (43,388 km2 total) that comprised 73% of known skunk rabies locations in the state. Scenario 2 also assumed baiting these eight zones, but further assumed that added benefits would result from preventing the spread of skunk-variant rabies into Los Angeles County, USA. Scenarios assumed a fixed bait cost ($1.24 each) but varied campaigns (one, two and three annual ORV applications), densities of …


Impact Of Age And Sex Of Rocky Mountain Elk (Cervus Elaphus Nelson) On Follicle Counts From Rectal Mucosal Biopsies For Preclinical Detection Of Chronic Wasting Disease, Terry R. Spraker, Kurt C. Vercauteren, Tom L. Gidlewski, Randy D. Munger, W. David Walter, Aru Balachandran Walter Jan 2009

Impact Of Age And Sex Of Rocky Mountain Elk (Cervus Elaphus Nelson) On Follicle Counts From Rectal Mucosal Biopsies For Preclinical Detection Of Chronic Wasting Disease, Terry R. Spraker, Kurt C. Vercauteren, Tom L. Gidlewski, Randy D. Munger, W. David Walter, Aru Balachandran Walter

United States Department of Agriculture Wildlife Services: Staff Publications

To determine if the number of rectal lymphoid follicles decreases with respect to age and sex relative to diagnosis of chronic wasting disease (CWD), rectal biopsies (n = 1,361) were taken from captive Rocky Mountain elk (Cervus elaphus nelsoni) at 4 ranches in the western United States between 2005 and 2008. Rectal tissues were stained with a monoclonal antibody (F99/97.6.1), which selectively stains the abnormal isoform of the prion protein associated with CWD of elk. The number of lymphoid follicles obtained from typical biopsy tissues decreased with the age of the animal. The acceptable number of lymphoid follicles …


Evaluation Of An Epitope-Blocking Enzyme-Linked Immunosorbent Assay For The Detection Of Antibodies To Influenza A Virus In Domestic And Wild Avian And Mammalian Species, Heather J. Sullivan, Bradley J. Blitvich, Kaci K. Vandalen, Kevin T. Bentler, Alan B. Franklin, J. Jeffrey Root Jan 2009

Evaluation Of An Epitope-Blocking Enzyme-Linked Immunosorbent Assay For The Detection Of Antibodies To Influenza A Virus In Domestic And Wild Avian And Mammalian Species, Heather J. Sullivan, Bradley J. Blitvich, Kaci K. Vandalen, Kevin T. Bentler, Alan B. Franklin, J. Jeffrey Root

United States Department of Agriculture Wildlife Services: Staff Publications

An epitope-blocking enzyme-linked immunosorbent assay (bELISA) was developed for the detection of antibodies to influenza A virus in taxonomically diverse domestic and wild vertebrate species. In contrast to the bELISAs published previously that require reagent production, manipulation by the end-user, or have not been evaluated for use with both mammalian and avian species, this assay is performed using commercially available recombinant nucleoprotein antigen and corresponding nucleoprotein-specific monoclonal antibody and has been shown to work with multiple avian and mammalian species. The efficacy of the bELISA as a serum screening assay was compared to the agar gel immunodiffusion (AGID) assay using …


Threshold Concentrations Of An Anthraquinone-Based Repellent For Canada Geese, Red-Winged Blackbirds, And Ring-Necked Pheasants, Scott J. Werner, James C. Carlson, Shelagh K. Tupper, Michele M. Santer, George M. Linz Jan 2009

Threshold Concentrations Of An Anthraquinone-Based Repellent For Canada Geese, Red-Winged Blackbirds, And Ring-Necked Pheasants, Scott J. Werner, James C. Carlson, Shelagh K. Tupper, Michele M. Santer, George M. Linz

United States Department of Agriculture Wildlife Services: Staff Publications

Wildlife repellents provide a non-lethal alternative for managing the monetary impacts of agricultural depredation. For the purpose of developing of an effective avian repellent, we established repellency thresholds of an anthraquinone-based repellent for Canada geese (Branta canadensis), red-winged blackbirds (Agelaius phoeniceus), and ring-necked pheasants (Phasianus colchicus) in captivity. We conducted a concentration–response experiment with Canada geese offered cornseeds treated with six concentrations of Avipel repellent (a.i. 50% 9,10-anthraquinone). Based upon our laboratory efficacy data, we used non-linear regression to predict a threshold concentration of 1450 ppm anthraquinone for geese offered treated corn seeds (i.e., …


Options For The Control Of Disease 3: Targeting The Environment, Alastair Ward, Kurt C. Vercauteren, W. David Walter, Emmanuellle Gilot-Fromont, Sophie Rossi, Gareth Edwards- Jones, Mark S. Lambert, Michael R. Hutchings, Richard J. Delahay Jan 2009

Options For The Control Of Disease 3: Targeting The Environment, Alastair Ward, Kurt C. Vercauteren, W. David Walter, Emmanuellle Gilot-Fromont, Sophie Rossi, Gareth Edwards- Jones, Mark S. Lambert, Michael R. Hutchings, Richard J. Delahay

United States Department of Agriculture Wildlife Services: Staff Publications

Management of wildlife disease can be targeted at pathogens, hosts or vector populations, but may also focus on the environment. As constituent elements of any given environment, resident wildlife populations, and their pathogens, may be profoundly influenced by environmental change, in terms of their abundance, distribution and behavior. Hence, it is reasonable to expect that incorporation of environmental manipulation into a program to control wildlife diseases may potentially result in outcomes as effective as direct intervention aimed at hosts, pathogens and vectors.


Crop, Native Vegetation, And Biofuels: Response Of White- Tailed Deer To Changing Management Priorities, W. David Walter, Kurt C. Vercauteren, Jason Gilsdorf, Scott E. Hygnstrom Jan 2009

Crop, Native Vegetation, And Biofuels: Response Of White- Tailed Deer To Changing Management Priorities, W. David Walter, Kurt C. Vercauteren, Jason Gilsdorf, Scott E. Hygnstrom

United States Department of Agriculture Wildlife Services: Staff Publications

The expansion of the cellulosic biofuels industry throughout the United States has broad-scale implications for wildlife management on public and private lands. Knowledge is limited on the effects of reverting agriculture to native grass, and vice versa, on size of home range and habitat use of white-tailed deer (Odocoileus virginianus). We followed 68 radio-collared female deer from 1991 through 2004 that were residents of DeSoto National Wildlife Refuge (DNWR) in eastern Nebraska, USA. The refuge was undergoing conversion of vegetation out of row-crop agriculture and into native grass, forest, and emergent aquatic vegetation. Habitat in DNWR consisted of …


Improving Follow-Up Of Abnormal Cancer Screens Using Electronic Health Records: Trust But Verify Test Result Communication, Hardeep Singh, Lindsey Wilson, Laura A Petersen, Mona K Sawhney, Brian Reis, Donna Espadas, Dean F Sittig Jan 2009

Improving Follow-Up Of Abnormal Cancer Screens Using Electronic Health Records: Trust But Verify Test Result Communication, Hardeep Singh, Lindsey Wilson, Laura A Petersen, Mona K Sawhney, Brian Reis, Donna Espadas, Dean F Sittig

Faculty, Staff and Student Publications

BACKGROUND: Early detection of colorectal cancer through timely follow-up of positive Fecal Occult Blood Tests (FOBTs) remains a challenge. In our previous work, we found 40% of positive FOBT results eligible for colonoscopy had no documented response by a treating clinician at two weeks despite procedures for electronic result notification. We determined if technical and/or workflow-related aspects of automated communication in the electronic health record could lead to the lack of response.

METHODS: Using both qualitative and quantitative methods, we evaluated positive FOBT communication in the electronic health record of a large, urban facility between May 2008 and March 2009. …


Taxonomy Development And Knowledge Representation Of Nurses' Personal Cognitive Artifacts, Sharon Mclane, James P Turley Jan 2009

Taxonomy Development And Knowledge Representation Of Nurses' Personal Cognitive Artifacts, Sharon Mclane, James P Turley

Faculty, Staff and Student Publications

Nurses prepare knowledge representations, or summaries of patient clinical data, each shift. These knowledge representations serve multiple purposes, including support of working memory, workload organization and prioritization, critical thinking, and reflection. This summary is integral to internal knowledge representations, working memory, and decision-making. Study of this nurse knowledge representation resulted in development of a taxonomy of knowledge representations necessary to nursing practice.This paper describes the methods used to elicit the knowledge representations and structures necessary for the work of clinical nurses, described the development of a taxonomy of this knowledge representation, and discusses translation of this methodology to the cognitive …


Ontology Driven Integration Platform For Clinical And Translational Research, Parsa Mirhaji, Min Zhu, Mattew Vagnoni, Elmer V. Bernstam, Jiajie Zhang, Jack W. Smith Jan 2009

Ontology Driven Integration Platform For Clinical And Translational Research, Parsa Mirhaji, Min Zhu, Mattew Vagnoni, Elmer V. Bernstam, Jiajie Zhang, Jack W. Smith

Faculty, Staff and Student Publications

Semantic Web technologies offer a promising framework for integration of disparate biomedical data. In this paper we present the semantic information integration platform under development at the Center for Clinical and Translational Sciences (CCTS) at the University of Texas Health Science Center at Houston (UTHSC-H) as part of our Clinical and Translational Science Award (CTSA) program. We utilize the Semantic Web technologies not only for integrating, repurposing and classification of multi-source clinical data, but also to construct a distributed environment for information sharing, and collaboration online. Service Oriented Architecture (SOA) is used to modularize and distribute reusable services in a …


The Germination Ecology And Composition Of The Indigenous Seeds Of Cyprus Conglomeratus: A Sand Dune Binder, Sheikha Saeed Amer Al Neyadi Jan 2009

The Germination Ecology And Composition Of The Indigenous Seeds Of Cyprus Conglomeratus: A Sand Dune Binder, Sheikha Saeed Amer Al Neyadi

Theses

Cyperus conglomeratus is among few species that tolerate the instability of sand dunes and its low nutrients. This species tolerates grazing animals and sand burial. It is considered as a good fodder for both domestic and wildlife animals. It has the potential to fix sand dunes. In addition, a preliminary observation indicated the presence of high contents of oil in the seeds. Despite the ecological importance of C. conglomeratus, little information is available about germination behaviour and seed composition. The present study assessed the dormancy, germination requirement, tolerance to salinity and drought during germination stage, the impact of dormancy regulation …


Flocking In The Time-Dissonance Plane, Adam James Wilson Jan 2009

Flocking In The Time-Dissonance Plane, Adam James Wilson

Publications and Research

This paper describes a technique for the sonification of an idealized model of the flocking behavior of birds, fish, and insects. Flocking agents are represented by pitches that move through time to produce chords of variable dissonance. The objective of each agent is to move toward more consonant chord formations with other agents. The output of the sonification is intended to provide material for use in musical composition.


A Symbolic Sonification Of L-Systems, Adam James Wilson Jan 2009

A Symbolic Sonification Of L-Systems, Adam James Wilson

Publications and Research

This paper describes a simple technique for the sonification of branching structures in plants. The example is intended to illustrate a qualitative definition of best practices for sonification aimed at the production of musical material. Visually manifest results of tree growth are modelled and subsequently mapped to pitch, time, and amplitude. Sample results are provided in symbolic music notation.


Two-Dimensional Gravity Modeling Of The Rattlesnake Springs Watershed, Carlsbad Caverns National Park, New Mexico, Nikolay D. Boykov Jan 2009

Two-Dimensional Gravity Modeling Of The Rattlesnake Springs Watershed, Carlsbad Caverns National Park, New Mexico, Nikolay D. Boykov

Open Access Theses & Dissertations

A series of non-invasive geophysical investigations at the Rattlesnake Springs part of Carlsbad Caverns National Park, New Mexico, were performed in an effort to better delineate the watershed of the springs. The goal of this project is to determine possible locations of fractures and faults that may control the distribution of groundwater that feeds Rattlesnake Springs. Once the water flow paths are identified, the park will be able to better protect Rattlesnake Springs from environmental hazards, such as oil and gas drilling, as well as from upstream water development. As part of this effort I conducted a precision gravity survey …


Magnitude Of Right-Lateral Offset On The Southern Death Valley Fault Zone From Miocene Volcanic Assemblages, Sabrina Michelle Canalda Jan 2009

Magnitude Of Right-Lateral Offset On The Southern Death Valley Fault Zone From Miocene Volcanic Assemblages, Sabrina Michelle Canalda

Open Access Theses & Dissertations

In this study correlation of Miocene volcanic and sedimentary rocks in southern Death Valley is used to constrain the total amount of slip on the southern Death Valley fault. The tertiary volcanic section near Ibex Pass is correlated to rocks ~35 km to the northwest, in the Wingate Wash region (Luckow et al., 2005). Geochronology by Luckow et al. (2005) in Wingate Wash and the Owlshead Mountains has the region divided into two basic periods: an early interval (~14-13.4Ma), and a later phase (~13-12.5Ma). One date from the volcanic sequence in Ibex Pass has been reported (Calzia, 2000) suggesting that …


The Pluvial Lake Palomas - Samalayuca Dunes System, Miguel Dominguez Acosta Jan 2009

The Pluvial Lake Palomas - Samalayuca Dunes System, Miguel Dominguez Acosta

Open Access Theses & Dissertations

A lacustro-aeolian system formed by the Pluvial Lake Palomas (PLP), the Samalayuca Dunes (SMD) and a connecting aeolian corridor is found in the central Chihuahuan Desert of North America approximately 50 km upwind (SW) of the binational Paso del Norte metroplex. The system is described by its three individual components. They comprise one of the largest paleo-lacustrine (Pleistocene) environments in the Chihuahuan Desert (PLP), one of the largest and least-studied sand seas of North America (SMD), and a newly described and geomorphically heterogeneous aeolian corridor connecting the two.

The Chihuahuan Desert has been a major and underappreciated dust production region …


Appropriate Prosodic Variation Is Valued By Users, Rafael Escalante-Ruiz Jan 2009

Appropriate Prosodic Variation Is Valued By Users, Rafael Escalante-Ruiz

Open Access Theses & Dissertations

Spoken dialog systems today do not vary the prosody of their utterances, although prosody is known to have many useful expressive functions. In a corpus of memory quizzes, I identified eleven dimensions of prosodic variation, each with its own expressive function. I identified the situations in which each was used, and how to detect these situations from the dialog context and the prosody of the interlocutor's previous utterance. I implemented the resulting response rules and had 21 users interact with two versions of the system. Overall they preferred the version in which the prosodic forms of the acknowledgments were chosen …


Suswa Volcano, Kenya Rift: Evidence Of Magma Mixing, Na-F Complexing And Eruptions Triggered By Recharge, Vanessa Veronica Espejel Garcia Jan 2009

Suswa Volcano, Kenya Rift: Evidence Of Magma Mixing, Na-F Complexing And Eruptions Triggered By Recharge, Vanessa Veronica Espejel Garcia

Open Access Theses & Dissertations

The Cenozoic East African rift system (EARS) is a sequence of grabens, intraplate transforms, accommodation zones, and abundant magmatism. The Central Kenya Peralkaline Province (CKPP) includes a variety of volcanic rocks -trachyte, pantellerite, comendite, phonolite, trachy-basalt, basaltic trachy-andesite, and basalt- which erupted from volcanoes including: Mount Kenya; Eburru and the Greater Olkaria volcanic complexes; Longonot, Menengai, and Suswa volcanoes; and Ndabibi, Elmenteita, and Tandamara mafic volcanic fields. Only two of the volcanoes, Mount Kenya (on the flank of the central graben) and Suswa (the southernmost of the CKPP volcanoes), have phonolites as part of their assemblage.

The evolution of Suswa …


Sustainable Development Extension Plan (Sudex): Community Mobilization Through Proactive Participation And Synergistic Alliance To Alliviate Poverty And Achieve Sustainable Self Sufficiency, Stephen Forbes Jan 2009

Sustainable Development Extension Plan (Sudex): Community Mobilization Through Proactive Participation And Synergistic Alliance To Alliviate Poverty And Achieve Sustainable Self Sufficiency, Stephen Forbes

Open Access Theses & Dissertations

This Dissertation describes a sustainable development extension plan (Sudex Plan) to help communities in developing countries achieve Goal 1 of the United Nation's Millennium Development Goals (MDG). Goal 1 focuses on reducing poverty and hunger by 50% by the year 2015, but all the MDG are interrelated and one can not be achieved without considering the others, and to attain any is an empty accomplishment without ways to ensure that they can be sustained and continuously improved with the means to pass on the information, knowledge and lessons learned from community to community, generation to generation. The Sudex Plan is …


Insight Into The Physics Of Rupture: Dynamic Triggering Seismicity, Hector Gonzalez-Huizar Jan 2009

Insight Into The Physics Of Rupture: Dynamic Triggering Seismicity, Hector Gonzalez-Huizar

Open Access Theses & Dissertations

Seismic waves can trigger earthquakes and tremor at large distances from the causable event. Dynamic triggering occurs when the surface waves from large earthquakes change the stresses conditions on previously overstressed faults, promoting failure. To understand the causative stresses and environments behind dynamic triggering, we model the change in the stress field that the passing of Rayleigh and Love waves cause on a fault plane of arbitrary orientation relative to the direction of propagation of the waves, and apply a Coulomb failure criterion to calculate the potential of these stress changes to trigger seismicity. We apply our model to three …


Identification Of Human Gait Using Genetic Algorithm Tuned Fuzzy Logic, Abdallah Abdel-Rahman Hassan Mahmoud Jan 2009

Identification Of Human Gait Using Genetic Algorithm Tuned Fuzzy Logic, Abdallah Abdel-Rahman Hassan Mahmoud

Open Access Theses & Dissertations

Data mining is concerned with the discovery of useful hidden information in large databases. Classification is a data mining task producing rules in which a set of attributes in data predict the value of a class attribute. Classifiers usually produce a large number of rules, most of which are not interesting to the user. Rule interestingness is a decisive factor. However, evaluating rule interestingness is challenging as it involves both objective (data-driven) and subjective (user-driven) aspects.

In this research, a fuzzy genetic algorithm is proposed to discover classification rules that are both accurate and interesting. Continuous attributes are fuzzified so …


Towards More Reliable Extrapolation Algorithms With Applications To Organic Chemistry, Jaime Nava Jan 2009

Towards More Reliable Extrapolation Algorithms With Applications To Organic Chemistry, Jaime Nava

Open Access Theses & Dissertations

One of the main objectives of science and engineering is to predict the results of different situations. For example, in Newton's mechanics, we want to predict the positions and velocities of different objects (e.g., planets) at future moments of time.

In this Thesis, as a case study, we take the problem of predicting the properties of new chemical substances. One of the main objectives of chemistry is to design new molecules (and, more generally, new chemical compounds) which are useful for various practical tasks. New substances have already resulted in new materials for buildings and for spaceships, new explosives and …


Land Resources Series No 21 - Tambellup-Borden Area Land Resources Survey, Angela Stuart-Street, Rohan Marold Jan 2009

Land Resources Series No 21 - Tambellup-Borden Area Land Resources Survey, Angela Stuart-Street, Rohan Marold

Natural resources published reports

AGDEX 526

Land Resources Series No. 21

This report presents results from soil-landscape mapping at a scale of 1: 100,000 in the Tambellup- Borden area of Western Australia. It is accompanied by a soil-landscape map covering almost 511,000 hectares.

Most of the survey occurs within the upper Frankland-Gordon, Kent, North Stirlings Basin and upper reaches of the Pallinup and Kalgan River catchments. The survey falls within the Katanning and Albany Department of Agriculture and Food advisory districts.

Seventeen soil-landscape systems have been identified and are represented on the map on the accompanying CD-ROM. These systems have been further divided into …


Pdi, Reactive Oxygen Species Stress And Polyphenolic Phytochemicals: Implications For Neurodegenerative Diseases, Rituraj Pal Jan 2009

Pdi, Reactive Oxygen Species Stress And Polyphenolic Phytochemicals: Implications For Neurodegenerative Diseases, Rituraj Pal

Open Access Theses & Dissertations

PDI, protein disulfide isomerase, is one of the most versatile proteins and highly expressed in mammalian cells because there is a vast number of proteins that must undergo processing before secretion to their final destinations. PDI has several functions: oxidation of nascent proteins and isomerization of existing disulfide bonds. It also possesses chaperone activity and participates in protein degradation. Because of its structure, PDI can exist in a reduced or oxidized form. In mammalian cells it is mostly reduced due to the high demand of disulfide bond shuffling of secreted proteins within the ER, PDI a, a', and b' posses …


A Retrospective Study Of Dust Storms And Respiratory Hospitalizations In El Paso, Texas Using A Case-Crossover Study Design, Yanlei Peng Jan 2009

A Retrospective Study Of Dust Storms And Respiratory Hospitalizations In El Paso, Texas Using A Case-Crossover Study Design, Yanlei Peng

Open Access Theses & Dissertations

Dust storms frequently occur in El Paso, Texas, but little is known about their respiratory health effects. The association between dust storm and hospitalization for respiratory illness will be studied through a case-crossover study design. The goal is to ascertain the effect of dust storms, adjusted for weather and other pollutants, and to explore the potential harmfulness for different subgroups of residents. A case-crossover study allows patients to serve as their own controls, in order to reduce confounding. The history, relationship, and application of the case-control and case-crossover study designs are reviewed in this thesis. The estimating equations for conditional …


Computational Modeling Studies Of The Structures And Properties Of Organotin(Iv) And Stannyl-Thioether Systems With Comparisons To X-Ray Crystallography, Michelle R. Stem Joseph Jan 2009

Computational Modeling Studies Of The Structures And Properties Of Organotin(Iv) And Stannyl-Thioether Systems With Comparisons To X-Ray Crystallography, Michelle R. Stem Joseph

Open Access Theses & Dissertations

Controlling the toxic effects of organotin(IV) compounds involves engineering the structure of the molecules to optimize their properties. Molecular engineering, coupled with improved capabilities to generate reliable computational optimization models (COMs), will enable researchers to have greater success at harnessing the highly specific cytotoxicity of organotins. For example, as the thion ligand phenyl groups were replaced with Cl atoms, the S-Sn intramolecularity was strengthened, the bond distance decreased, and the stannyl tetrahedral structure was deformed from its triphenyl conformation. With each substitution, conformation deformations lowered the damaging bioactivity levels of thion. Bonding various ligands to organotin(IV) compounds …


Multiplicative Riesz Decomposition On The Ring Of Matrices Over A Totally Ordered Field, Julio Cesar Urenda Jan 2009

Multiplicative Riesz Decomposition On The Ring Of Matrices Over A Totally Ordered Field, Julio Cesar Urenda

Open Access Theses & Dissertations

The Riesz Decomposition Theorem for lattice ordered groups asserts that when G is an l-group and when a nonnegative element a is bounded by a product of nonnegative elements b1,...,bn, then a can be decomposed into a product of nonnegative elements b'1,...,b'n, i.e., a = b'1·...·b' n, with the property that b'i ≤ bi for any i = 1,...,n. In this work we characterize all nonnegative matrices for which this decomposition is possible with respect to matrix multiplication. In addition, we show that this result can be applied to ordered semigroups.


Experimental Study Of The Response Of Semiconductor Detectors For Edxrf Analysis., Sunil Kumar Valaparla Jan 2009

Experimental Study Of The Response Of Semiconductor Detectors For Edxrf Analysis., Sunil Kumar Valaparla

Open Access Theses & Dissertations

This present work relates to the study and characterization of the response function of an energy-dispersive x-ray spectrometer. The problems of energy, efficiency and resolution calibration of the system operating in the energy (5-60 keV) range are discussed. We present the operation characteristics of the portable pyro-electric x-ray generator (COOL-X) and the application of the calibrated response spectrum in the elemental analysis using X-ray Fluorescence (XRF).

We study the response of the Si(Li)-Pin XR-100CR semiconductor detector to low energy photons. The photopeak efficiency was determined experimentally by using radioisotopes and compared against a theoretical efficiency curve. The efficiency for gamma …


Using Chromium Stable Isotopes To Monitor Chromium Reactive Transport: Oxidation Experiments And Field Studies, Alejandro Villalobos Aragon Jan 2009

Using Chromium Stable Isotopes To Monitor Chromium Reactive Transport: Oxidation Experiments And Field Studies, Alejandro Villalobos Aragon

Open Access Theses & Dissertations

Chromium (Cr) is a common contaminant found at a number of sites globally. Cr sources can be either anthropogenic or natural. Cr occurs in nature in two valences, with Cr(VI) being carcinogenic, more toxic and mobile than Cr(III). Reduction of Cr(VI) to Cr(III) is a common remediation strategy, but monitoring Cr reduction using only concentration and speciation analyses is a difficult endeavor because concentrations can be affected by dilution and advection in addition to reduction. Cr isotopes are fractionated during reduction processes, so monitoring isotopic changes in Cr may be a faster and more effective way to monitor reduction. This …


By-Product Synergy In The Textile Industry: Indigo Waste Recovery In The Denim Finishing Process, Dennis Wambuguh Jan 2009

By-Product Synergy In The Textile Industry: Indigo Waste Recovery In The Denim Finishing Process, Dennis Wambuguh

Open Access Theses & Dissertations

Textile dyeing effluents present a substantial environmental problem, primarily because such effluents contain high concentrations of waste dyes, dye-products, and variable salts. The stonewashing process for the degradation of blue indigo to create a `faded' look in blue denim results in high concentrations of indigo dye waste in the resulting effluent and because indigo is very difficult to decompose biologically, the effluent ends up in the environment, raising aesthetic concerns and damaging the integrity of the rceiving streams. Wastewater containing indigo is characterized by a moderate amount of chemical oxygen demand (COD), pH, suspended solids, dissolved solids and a dark …


Silica Removal From Brine By Using Ion Exchange, Carlos R. Acevedo Jan 2009

Silica Removal From Brine By Using Ion Exchange, Carlos R. Acevedo

Open Access Theses & Dissertations

Local governments have been forced to look for additional water sources to satisfy the ever increasing demand for fresh water. Very often, the new water sources such as the underground water in continental territories have high salt content. Currently, reverse osmosis technology (RO) is one of the most common processes for water desalination. However, this process is limited by high silica and salt concentrations in water. At high concentrations silica clogs the membranes used in the RO process, reducing their life and increasing operational costs. In this study, quaternary ammonium resins and sulfonic acid resins were used to remove silica …