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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
161

A Study of Freemont Snake Valley Black-on-gray Ceramics from Sites in Northern Utah and the Parowan Valley

Abo, Stephanie K.Y. 14 December 2020 (has links)
Archaeologists widely argue that Fremont potters from the Parowan Valley, in southwestern Utah, manufactured Snake Valley pottery. For my thesis, I examined Snake Valley Black-on-gray rim sherds using neutron activation analysis, oxidation analysis, metric data, and statistical methods. I compared my results on Snake Valley Black-on-gray sherds from three archaeological sites within the Parowan Valley (Paragonah, Parowan, and Evans Mound) to my results on Snake Valley Black-on-gray sherds recovered from three archaeological sites over 250 kilometers to the north (South Temple, Block 49, and Wolf Village). I argue that the Snake Valley Black-on-gray ceramics from the northern sites are tradewares selected from the Parowan Valley sites. My research expands on the limited knowledge of the painted variety of Snake Valley pottery; as well as provides insight into the overall understanding of Snake Valley Black-on-gray distribution among different geographical regions within the Fremont culture.
162

Characterization of a New D-D Neutron Generator System for Neutron Activation of Manganese in Bone In-Vivo

Elizabeth Helen Jaye (12463536) 27 April 2022 (has links)
<p>Neutron Activation Analysis (NAA) is a non-invasive method for assessing the qualitative and quantitative elemental composition of a sample. One application of this technique is in-vivo quantification of specific elements in the human body. An important element in terms of human exposure assessment is Manganese (Mn). Mn is the fourth most usedindustrial metal and can be an  inhalation  exposure  hazard  specifically  for  welders.  Over  exposure  to  Mn  can  lead  to neurological degeneration issues similar to Parkinson’s disease. It has been found that bone is a good  biomarker  for  Mnas  Mn  is  deposited  in  the  bone  and  remains  for  long  periods  of  time,allowing  for  an  assay  to  reveal  long  term  exposure  information.  The  method  of  using  NAA  to quantify levels of Mn in-vivo using the bones in the human hand is being explored in this work.The  NAA  system  used,  involves  a  deuterium-deuterium  neutron  generator  and  an  N-type  High Purity Germanium Detector. It is critical to have the performance of the entire system characterized using phantoms and cadaver bones before the system can be used for in-vivo measurements. The goal of this work is to determine the neutron yield of the generator system, the neutron and photon dose  received  by  a  sample,  the  detection  limit  of  Mn  with  this  system,  and  to  evaluate  the  Mn detection capability of the systemusing cadaver bones from occupationally exposed Mn miners. The parameters were determined through a combination of simulation with Monte Carlo N-Particle Code  (MCNP),  experiments  using  Mn  doped  bone  phantoms  and  cadaver  bones,  and  various dosimetry  tools such  as  TLDs  and  EPDs.  The  neutron  yieldfor the  D-D  109M  generator  wasestimated to be2.24E+09+/-2.15E+07neutrons per secondfor this work. The Mn detection limit for the system was estimatedto be 0.442 ppm. The equivalent dose received by the sampleduring the standard 10-minute irradiation was estimated to be 8.45 +/-2.05rem. The results found for the human cadaver bones weremixed. It was found that the system was able to successfully detect Mn incadaver bones. Unexpectedly, however, three of the samples showed little to no Ca signal.In addition, significant amounts of soft tissue and bone marrow exist in the samples.Thereforethe Mn concentration in the bones was not able to be accurately estimated. A relative metric of Mn concentration  was  used  instead  and  showed  a  slight  positive  increase  from  the  unexposed  to exposed samples but was not statistically significant.</p>
163

A Study of Fremont Snake Valley Black-on-gray Ceramics from Sites in Northern Utah and the Parowan Valley

Abo, Stephanie K.Y. 14 December 2020 (has links)
Archaeologists widely argue that Fremont potters from the Parowan Valley, in southwestern Utah, manufactured Snake Valley pottery. For my thesis, I examined Snake Valley Black-on-gray rim sherds using neutron activation analysis, oxidation analysis, metric data, and statistical methods. I compared my results on Snake Valley Black-on-gray sherds from three archaeological sites within the Parowan Valley (Paragonah, Parowan, and Evans Mound) to my results on Snake Valley Black-on-gray sherds recovered from three archaeological sites over 250 kilometers to the north (South Temple, Block 49, and Wolf Village). I argue that the Snake Valley Black-on-gray ceramics from the northern sites are tradewares selected from the Parowan Valley sites. My research expands on the limited knowledge of the painted variety of Snake Valley pottery; as well as provides insight into the overall understanding of Snake Valley Black-on-gray distribution among different geographical regions within the Fremont culture.
164

Aspects of later Roman pottery assemblages in Northern England. Investigation of Roman pottery assemblages and supply with emphasis on East Yorkshire industries, and of the potential of neutron activation analysis for fabric characterisation.

Evans, Jeremy January 1985 (has links)
This study has attempted to examine third and fourth century pottery supply in northern England together with other aspects of pottery assemblages in the region. The pottery kilns of the East Yorkshire industries have been characterised by neutron activation analysis which has proved reasonably successful in discriminating between them. Neutron activation analysis has also been utilised to attempt to check visually identified fabric groups and to help isolate other fabrics. This has been of varying success. Quantified data has been collected from 15 sites across the north and the limited published quantitative data have been utilised to examine the distribution, marketing and competition between fabric types in the region. Examination of functional variations through time between different types of site has also been undertaken as has that of variations in the quantity of finewares through time and between different types of site together with an attempt at quantifying decoration and examining trends in this. Pottery supply to the northern frontier area would seem to have been organised by different mechanisms in different periods. In the second century much of the pottery used on the frontier would appear to have been produced by the military themselves whilst in the third century and earlier fourth century free market mechanisms would seem to have operated, but in the late fourth-early fifth centuries some form of 'military contract' would appear to have taken over supply. Functional variations between different types of site have been identified with rural sites, turrets and Signal Stations sharing a major emphasis on the jar as the basic ceramic form and more complex settlement types having more diversified functional groups. The distribution of finewares also seems to be concentrated on more complex settlement types. It is apparent that there are consistent differences between the East Yorkshire region and the rest of the study area which may well reflect differences extending back into the Iron Age. Similarly there seem to be indications of some 'de-Romanisation' in late Roman assemblages but this does not develop in the fifth century, when nearly all the strands of evidence of Romano-British material culture disappear very rapidly. / Science and Engineering Research Council
165

Palladium, Iridium and Gold in Deep-Sea Cores

Kuo, Hsiao-Yu 05 1900 (has links)
<p> Wet chemical neutron activation analysis procedures for Au., Pd and Ir together with a non-destructive gamma-counting procedure for Mn are described and applied to the determination of these metals in three Antarctic (E21 -17, E13-3 and E 17-10) and one Caribbean (P63 04-9) deep-sea cores. A total of 49 samples were analyzed. The average values of Au, Pd, Ir in ppb and Mn in Wt.% (together with standard deviations of the mean are: (see table in theses) No large differences exist between Au, Pd and Ir concentrations in different types of deep-sea sediments nor in cores from different areas and their values are within the general concentration range found in most crustal rocks. A general discussion of the sources of precious metals in deep-sea sediments is given. The most important precious metal source in the cores studied in this work is detrital material from land. The contribution of extraterrestrial material to the Au and Pd content of deep-sea sediments is not important but in cores with depositional rates as low as a few tenths of a mm per thousand years, extraterrestrial material may account for more than half of the total Ir content. From the non-detrital Ir content of deep-sea manganese nodules the accretion rate of extraterrestrial material over the. entire surface of the earth is calculated to be about 200 tons per day with an upper limit of 310 tons per day. The constancy of Ir content in deep-sea cores as a function of depth suggests that the influx of extraterrestrial material during the past 3 to 4 million years was probably fairly constant. </p> / Thesis / Master of Science (MSc)
166

In Vivo Measurement of Aluminum in Alzheimer's Disease and Related Studies

K. Mohseni, Hedi January 2016 (has links)
Alzheimer’s disease accounts for up to 80% of the cases of dementia making it the most common type of dementia. As of 2015, 46.8 million people are suffering from Alzheimer’s disease worldwide with an alarming rate of increase in the onset of the disease. Despite the ongoing research, the true cause of Alzheimer’s disease remains unknown. Aluminum is one of the major environmental toxins linked to the etiology of Alzheimer’s disease. A pilot clinical study for non-invasive measurement of bone aluminum was performed at the in vivo neutron activation analysis facility at McMaster University including 15 Alzheimer’s and 15 control subjects. A significant difference in bone aluminum, relative to calcium, was found between the two groups. Multiple methods of analysis were investigated to determine the method with the lowest minimum detection limit. The method of in vivo neutron activation analysis allows for the simultaneous activation of multiple elements. As such, it was possible to measure the magnesium levels, which has been shown to be involved in Alzheimer’s disease, in the study subjects. The results of bone measurements did not show a significant association between bone magnesium levels and Alzheimer’s disease. Moreover, the short-term kinetic behaviours of sodium and chlorine, both essential for the human body, were studied. The outcome of this study revealed an increase in the biological half-lives of sodium and chlorine with age and a higher variability in Alzheimer’s patients compared to control subjects. Finally, bone samples from parenteral nutrition patients were analyzed to determine their aluminum content for comparison and benchmarking purposes. The present results suggest a possible association between bone aluminum and the presence of Alzheimer’s disease. No such association was found for magnesium or the biological half-lives of sodium and chlorine. The technique of in vivo neutron activation analysis was shown to be a promising tool for measuring bone aluminum and magnesium; however, a better detection limit is required to strengthen the current results. / Dissertation / Doctor of Philosophy (PhD) / Alzheimer’s disease is the most common form of dementia. The cause of Alzheimer’s disease is unknown, but both genetic and environmental factors are known to be involved. Different elements have been studied for their possible role in this disease. Aluminum and to a lesser extent magnesium have been linked to the etiology of Alzheimer’s disease. The current thesis presents the results of a clinical study that utilizes the method of in vivo neutron activation analysis to measure aluminum and magnesium in the hand bone of Alzheimer’s disease and control subjects. In vivo neutron activation analysis is a non-invasive method that uses neutrons to activate elements in the human body and measures the radiation emitted. Different methods of analyzing the resulting data were investigated to find the most suitable analysis approach. The biological half-lives of sodium and chlorine were also measured to investigate their short-term kinetic behaviour and pattern with age.
167

Evaluation of Short Term versus Long Term Air Quality Sampling Methods Using X-ray Fluorescence and Neutron Activation Analysis

Stratton, Charles D. 20 April 2011 (has links)
No description available.
168

Analytical Methods for Toxic Metals and Proteins and Synthesis of Perovskites

Smith, Debbie A. 16 November 2010 (has links)
No description available.
169

NEUTRON ACTIVATION ANALYSIS OF MANGANESE, IRON AND ZINC IN A RODENT MODEL OF DYSMYELINATION

Lobo, Lianne R. 10 1900 (has links)
<p>Transition metals such as manganese (Mn), iron (Fe) and zinc (Zn) are some of the essential metals for normal CNS development and function. Each must be present at specific levels to avoid deficiencies or toxic excess. The research in this thesis investigates the role of transition metals in diseases in which myelin is lost in the central nervous system (CNS). A loss of myelin is termed demyelination, and an example of a disease with prominent demyelination is multiple sclerosis. An incomplete formation of myelin sheaths is termed dysmyelination. This thesis focused on the measurements of manganese, iron and zinc concentrations in a rodent model of dysmyelination; the Long Evans Shaker (<em>les</em>) rat.<strong></strong></p> <p>The Long Evans Shaker (<em>les</em>) rat is a fragile, severely dysmyelinated rodent model with body tremors at a young age and severe ataxia in older rats. The mutation causing the severe dysmyelination in these rats is transmitted as an autosomal recessive trait. With a lifespan of 4 to 5 months, the <em>les</em> rat is markedly deficient in myelin in the CNS, where most axons are entirely naked and the remaining ones are surrounded by a loosely woven, thin myelin sheath.</p> <p>In this thesis we studied alterations in manganese, iron and zinc transition metal levels in 3 and 16-week-old <em>les</em> rats and their age-matched control counterparts. Using neutron activation analysis (NAA), manganese measurements were made in the brain, spinal cord and visceral organs using an existing protocol, while a new assay was developed for iron and zinc measurements that were made in the spinal cord tissues. The higher trend in manganese concentration observed within the 3 and 16 week old <em>les</em> rats in comparison to the controls, where there was a significant increase (ples cerebellum, supports evidence suggesting that manganese levels are associated with astrogliosis. Whereas for iron and zinc, which were measured in the spinal cord tissues, there was also an overall increase in the levels of these metals in the <em>les</em> mutant strain when compared to the controls; however, only significant increases in zinc concentration within the 16 week old <em>les </em>spinal cords were observed.</p> <p>The characterization of the <em>les</em> rodent model mutation and its biochemical abnormality will advance our understanding of not only the process of myelination, but also diseases related to aberrant myelination or the maintenance of myelin sheaths.</p> / Master of Science (MSc)
170

Participação de complexos de lantanídeos entre as fases de reservatório de petróleo

Cíntia Helena de Freitas 15 March 2007 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Traçadores são utilizados na explotação de reservatórios de petróleo para fornecer informações que auxiliam na otimização das operações envolvidas. Esta utilização já é comumente praticada fora do Brasil, sendo os mais empregados os radioativos, que apresentam sobre os compostos químicos as vantagens da simplicidade e sensibilidade de detecção e do custo. Uma possibilidade interessante é representada pelos traçadores ativáveis, que podem ser introduzidos no sistema a estudar no estado inativo e serem posteriormente amostrados e dosados por Ativação Neutrônica. Para esta aplicação os elementos da série dos lantanídeos foram testados, visto que estes oferecem características nucleares adequadas para análise. Os traçadores eficientes serão aqueles que não se atrasem ou se percam por interação com as rochas e/ou fluidos não aquosos presentes no reservatório, ou seja, que possuam elevada solubilidade em fase aquosa, coeficientes de partição nulos com a fase orgânica e que não sejam adsorvidos nas elevadas superfícies específicas disponíveis nas formações microporosas das quais desalojam as gotículas de petróleo. Deste modo foi necessário a complexação e quantificação do rendimento através da técnica de Cromatografia Líquida de Alta Eficiência (CLAE). As técnicas espectrométricas de Ressonância Magnética Nuclear (1H e 13C) e Infravermelho (IV) também foram empregadas para caracterização das espécies formadas. Foram realizados testes com o lantânio (La), o európio (Eu) e o disprósio (Dy) com os ligantes ácidos aminopolicarboxílicos (EDTA-2, DTPA) e tia-dicarboxílicos (C4H6SO4 , C7H12S2O4). Após a quantificação do rendimento e caracterização dos complexos de lantanídeos, concluiu-se que há complexação das espécies ligantes com os lantanídeos estudados. Os complexos obtidos em maior rendimento foram então submetidos a testes que simulam uma possível partição destes com a fase orgânica (Kp) e/ou sólida (Kd) do aqüífero, pela metodologia da Análise por Injeção em Fluxo (Flow Injection Analysis FIA) e por testes em um corpo de prova que simula as condições de fluxo em um reservatório de petróleo. O cálculo da partição determinada por Ativação Neutrônica e Espectrometria de Emissão Atômica com Plasma Indutivamente Acoplado (ICP/AES) apresentou um resultado nulo, o que torna possível a utilização dos respectivos complexos como traçadores ambientais em campo de petróleo. Os testes em corpo de prova evidenciaram uma excelente concordância entre o comportamento dos lantanídeos complexados e do traçador de referência (água tritiada). Um outro teste com a metaloporfirina (MnP) foi realizado como estágio prévio para o desenvolvimento de um novo traçador e os resultados positivos indicaram a viabilidade de sua futura utilização. Foram realizados os mesmos testes que para os complexos de lantanídeos, sendo que as determinações dos coeficientes de partição tanto com a fase orgânica (Kp) como com a fase sólida (Kd) foram efetuadas através da Espectrometria UV-Vis. / Tracers are used in the explotation of petroleum reservoirs in order to obtain information that help to optimize its operations. They are presently used on a routine basis in many countries, and the more often applied are the radiotracers, due to some advantages they have over the chemical tracers, such as the simplicity and the sensitivity of their detection besides the cost factor. One of the most conspicuous applications of tracers to reservoirs production activities refers to the evaluation of the secondary recovery techniques, due to their capability to inform about what happens in between the injection and production wells, differently from the other techniques that provide information only at discrete points. An option of interest for the normally required multiple tracer tests is afforded by activable tracers that can be fed to the system under study in the inactive state and have their samples collected at the exit irradiated and measured by Neutron Activation Analysis. Some of the elements of the lanthanide series that exhibit very high thermal neutron cross sections have been tested for this purpose. A properly performing tracer should not lag behind the liquid flow nor be lost through interactions with the rocks and non aqueous fluids inside the reservoir. This means that they must be quite hydrophilic, and have nearly null partition coefficients so that they are neither adsorbed on the internal surfaces of the rock pores nor migrate to the oil phase. Hence it has been necessary to form complexes of the lanthanide metals with appropriate ligands. Besides, to certify the product and to measure the achieved yield, these complexes had to be analyzed by High Performance Liquid Chromatography (HPLC), by 1H and 13C Nuclear Magnetic Resonance (NMR), and by Infrared Spectrometry (IR). The analyses have confirmed the complexation of the lanthanides processed by a previously selected methodology. Following that the performance of these lanthanide complexes as tracers have been tested in essays that simulate the possibility their partition in the oil phase (Kp) as well as their adsorption (Kd) in the solids inside the reservoir, by means of the Flow Injection Analysis (FIA) technique and of core tests, respectively. Tests have carried with lanthanum, europium and dysprosium, that have been complexed with aminopolicarboxylic acids (EDTA2-, DTPA), and with tiacarboxylic acids (C4H6SO4, C7H12S2O4). The measurement of partition, that has been carried by both Instrumental Neutron Activation Analysis (INAA) and Internal Couple Plasma/Atomic Emission Spectrometry (ICP/AES), evidenced null partition and this qualifies these complexes as oil field tracers. The core tests also displayed an excellent match between the lanthanide complexeds and the reference tracer used (tritiated water). On e other test using metal-porphyrin (MnP) has been performed as a previous stage for the development of a novel tracer and the positive results obtained have shown its feasibility for future applications. This complex has been submitted to the same tests performed with the lanthanides and the measurement of both the water phase and the oil, phase partition coefficients (Kp and Kd, respectively) has been carried using UV-Vis spectrometry.

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