Work has been carried out to investigate the applicability of Neutron Induced Emission Tomography (NIET) to areas of non-destructive testing within the nuclear industry. The principal application was the scanning of irradiated nuclear fuel rods. In addition to its medical uses, tomography has been employed in many areas of non-destructive testing. However, the applications have generally used transmission tomography to examine structure. NIET provides a method of determining the spatial distribution of radionuclides produced by the action of neutrons by activation or fission processes. This has applications as an extension of neutron activation analysis and as a method of non-destructive testing for use in the nuclear industry. The work has involved the use of a number of experimental tomography scanners. Various test objects have been scanned using both emission and transmission tomography and computer programs were developed to collect, process and reconstruct the data. High resolution detectors were used to scan single and multi-energetic radionuclides in test objects designed to model various characteristics of nuclear fuel rods. The effects of scattering on image quality were examined and a method of scattering correction based upon the use of an additional energy window was applied. The work showed the viability of using NIET to study the distribution of radionuclides within objects such as irradiated fuel pellets. It also demonstrated the need for reducing the scattering component within images. The use of narrow energy windows and a high resolution detector were shown to be succesful in reducing the effects of scattering. The employment of scattering correction using additional energy windows was shown to be necessary when scanning multi-energetic radionuclides.

Over the past few decades, visualization and application researchers have been investigating vortices and have developed several algorithms for detecting vortex-like structures in the flow. These techniques can adequately identify vortices in most computational datasets, each with its own degree of accuracy. However, despite these efforts, there still does not exist an entirely reliable vortex detection method that does not require significant user intervention. The objective of this research is to solve this problem by introducing a novel vortex analysis technique that provides more accurate results by optimizing the threshold for several computationally-efficient, local vortex detectors, before merging them using the Bayesian method into a more robust detector that assimilates global domain knowledge based on labeling performed by an expert. Results show that when choosing the threshold well, combining the methods does not improve accuracy; whereas, if the threshold is chosen poorly, combining the methods produces significant improvement.

<p>   The need for RF spectrum for the rapidly growing broadband access services is evident. Cognitive radio is an emerging technology that aims to introduce secondary usage of the spectrum resources without interfering with the primary usage of the licensed users but with a lower priority.</p><p>   Signal detection for cognitive radios has drawn a lot of interest in the research community, where different algorithms are suggested. The most commonly used algorithms are energy detection, feature detection, eigenvalue based detection. Energy detection is the simplest and most common way to detect signals. It has fast sensing time but poor performance. The feature detection and eigenvalue based detection methods are more sophisticated and offer better performance but they are more complex and expensive. This thesis will present the pros and cons of each method and offer comparisons between them.</p><p>   To evaluate the performance of different algorithms used in cognitive radio, different research testbeds have been suggested in the literature. Some of the most frequently used testbeds are based on GNU-radio, WARP, or BEE2. GNU-radio is the simplest testbed and is free, but it has low bandwidth and poor performance. WARP and BEE2 are more advanced testbeds. They offer good performance and are easy to update, but they are more complex and expensive. These three testbeds will be described, compared, and their advantages and disadvantages will be observed in this thesis.</p>

The need for RF spectrum for the rapidly growing broadband access services is evident. Cognitive radio is an emerging technology that aims to introduce secondary usage of the spectrum resources without interfering with the primary usage of the licensed users but with a lower priority.    Signal detection for cognitive radios has drawn a lot of interest in the research community, where different algorithms are suggested. The most commonly used algorithms are energy detection, feature detection, eigenvalue based detection. Energy detection is the simplest and most common way to detect signals. It has fast sensing time but poor performance. The feature detection and eigenvalue based detection methods are more sophisticated and offer better performance but they are more complex and expensive. This thesis will present the pros and cons of each method and offer comparisons between them.    To evaluate the performance of different algorithms used in cognitive radio, different research testbeds have been suggested in the literature. Some of the most frequently used testbeds are based on GNU-radio, WARP, or BEE2. GNU-radio is the simplest testbed and is free, but it has low bandwidth and poor performance. WARP and BEE2 are more advanced testbeds. They offer good performance and are easy to update, but they are more complex and expensive. These three testbeds will be described, compared, and their advantages and disadvantages will be observed in this thesis.

<p dir="ltr">Efficiently identifying commercial and improvised explosives is a crucial prerequisite for disarming and disposing of these dangerous materials. In conjunction with traditional techniques (e.g., ion mobility spectrometry and mass spectrometry), electrochemical sensors can function as low-form factor and inexpensive options to quickly identify chemical threats. In particular, organic electrochemical transistors (OECTs) have many attractive properties, and they have become viable options for biosensing. OECTs employ a simple geometry consisting of a conducting polymer active layer and an electrolyte controlled by a gate electrode. In turn, this provides a means for the solution-phase detection in short times. Here, the OECT architecture was extended to the challenge of explosive trace detection. These sensors were adapted to detect several families of explosives (i.e., acid-salts, nitroaromatics, nitroamines, nitrate-esters, and peroxides). Many of these sensors incorporated molecularly imprinted polymers (MIPs) to improve chemical selectivity. These MIPs were shown to introduce size exclusive properties to the OECTs, which can be leveraged to detect acid salts explosives. MIPs that were complementary to nitrated explosives (nitroaromatics, nitroamines, and nitrate-esters) also were prepared. These MIPs can adsorb their respective explosive decreasing their polymer porosity and ion-transport. Finally, a stand-alone OECT design was applied to detect peroxide-based explosives. These explosives were decomposed to hydrogen peroxide intermediates. The evolved hydrogen peroxide was then identified as it was electro-oxidized at the gate electrode. After establishing the viability of the discussed techniques, two new directions for designing OECT sensors were proposed. Finally, these two outlooks were combined as a potential strategy for directly detecting peroxide-based explosives. While only a small subset of explosives was considered, the strategies applied were not unique to these specific targets. Indeed, these OECTs detecting principles could be applied to a broader scope of explosives detection as well as novel chemical sensing horizons.</p>

A irradiação de alimentos é um meio de preservação de alimentos onde se utiliza uma técnica de processamento que expõe os alimentos a uma radiação ionizante controlada de alta energia. O tratamento realizado com o uso das radiações ionizantes em alimentos tem muitas aplicações tecnologicamente e tecnicamente viáveis incluindo a capacidade de melhorar a segurança microbiológica, reduzir os níveis de bactérias patogénicas, inibir a germinação de tubérculos, aplicação fitossanitária, conservar alimentos armazenados ou a estabilidade de armazenamento e também é utilizada para aumentar a vida de prateleira de determinados produtos devido à redução da contaminação por microrganismos. Em função do aumento do comércio internacional de alimentos e das crescentes exigências regulatórias dos mercados consumidores, cada vez mais países importadores e exportadores têm demonstrando interesse na irradiação de alimentos e desenvolvido pesquisas na aplicação prática desta tecnologia e de métodos de detecção do tratamento. Inúmeras pesquisas foram realizadas mundialmente, resultando em eficientes protocolos para identificar quais alimentos foram ou não irradiados. Até então, o \"mito\" que alimentos irradiados não poderiam ser detectados e que não eram formados quaisquer produtos únicos da radiação foi substituído pelo conhecimento que muitas mudanças podem ocorrer nos alimentos irradiados e essas mudanças poderiam ser utilizadas como ferramentas para identificar essa tecnologia. O processamento por radiação resulta em formações de padrões característicos de hidrocarbonetos saturados, aldeídos, metil e etil ésteres e 2-alcilciclobutanonas, dependendo da composição do ácido graxo do lipídio que compõe o alimento. Com isso a proposta do trabalho foi levantar dados para comparar os efeitos das diferentes doses de radiação gama e de elétrons em alimentos que possuem gordura para verificar as possíveis alterações decorrentes do uso da irradiação, como a presença de 2-Alcilciclobutanonas e também, mostrar os principais equipamentos utilizados para a irradiação de alimentos e suas categorias, com o objetivo de informar o publico em geral. / Food irradiation is a means of preserving food which uses a processing technique that exposes the foods at a controlled high energy ionizing radiation. The treatment with the use of ionizing radiation in foods has many applications technologically and technically feasible, including the ability to improve the microbiological safety and reducing levels of pathogenic bacteria, inhibiting the germination of tubers plant application, preserving stored foods or the stability of storage and is also used to increase the shelf life of certain products due to the reduction of contamination by microorganisms. Due to the increase of international trade in food and the growing regulatory requirements of consumer markets increasingly importing and exporting countries have shown interest in food irradiation and conducted research in the practical application of this technology and detection methods of treatment. Numerous surveys were conducted worldwide, resulting in efficient protocols to identify which foods were irradiated or not. Until then, the \"myth\" that irradiated food could not be detected and they were not formed any single radiation products has been replaced by the knowledge that many changes can occur in irradiated foods and these changes could be used as tools to identify this technology. The radiation processing resulting in characteristic patterns formations of saturated hydrocarbons, aldehydes, methyl and ethyl esters and 2-alcilciclobutanonas, depending on the fatty acid composition of the lipid that composes the food. Thus the purpose of this study was to collect data to compare the effects of different doses of gamma radiation and electron in foods that have fat to determine possible changes resulting from the use of irradiation, as the presence of 2-Alcilciclobutanonas and also show main equipment used for food irradiation and its categories, with the aim of informing the general public.

A irradiação de alimentos é um meio de preservação de alimentos onde se utiliza uma técnica de processamento que expõe os alimentos a uma radiação ionizante controlada de alta energia. O tratamento realizado com o uso das radiações ionizantes em alimentos tem muitas aplicações tecnologicamente e tecnicamente viáveis incluindo a capacidade de melhorar a segurança microbiológica, reduzir os níveis de bactérias patogénicas, inibir a germinação de tubérculos, aplicação fitossanitária, conservar alimentos armazenados ou a estabilidade de armazenamento e também é utilizada para aumentar a vida de prateleira de determinados produtos devido à redução da contaminação por microrganismos. Em função do aumento do comércio internacional de alimentos e das crescentes exigências regulatórias dos mercados consumidores, cada vez mais países importadores e exportadores têm demonstrando interesse na irradiação de alimentos e desenvolvido pesquisas na aplicação prática desta tecnologia e de métodos de detecção do tratamento. Inúmeras pesquisas foram realizadas mundialmente, resultando em eficientes protocolos para identificar quais alimentos foram ou não irradiados. Até então, o \"mito\" que alimentos irradiados não poderiam ser detectados e que não eram formados quaisquer produtos únicos da radiação foi substituído pelo conhecimento que muitas mudanças podem ocorrer nos alimentos irradiados e essas mudanças poderiam ser utilizadas como ferramentas para identificar essa tecnologia. O processamento por radiação resulta em formações de padrões característicos de hidrocarbonetos saturados, aldeídos, metil e etil ésteres e 2-alcilciclobutanonas, dependendo da composição do ácido graxo do lipídio que compõe o alimento. Com isso a proposta do trabalho foi levantar dados para comparar os efeitos das diferentes doses de radiação gama e de elétrons em alimentos que possuem gordura para verificar as possíveis alterações decorrentes do uso da irradiação, como a presença de 2-Alcilciclobutanonas e também, mostrar os principais equipamentos utilizados para a irradiação de alimentos e suas categorias, com o objetivo de informar o publico em geral. / Food irradiation is a means of preserving food which uses a processing technique that exposes the foods at a controlled high energy ionizing radiation. The treatment with the use of ionizing radiation in foods has many applications technologically and technically feasible, including the ability to improve the microbiological safety and reducing levels of pathogenic bacteria, inhibiting the germination of tubers plant application, preserving stored foods or the stability of storage and is also used to increase the shelf life of certain products due to the reduction of contamination by microorganisms. Due to the increase of international trade in food and the growing regulatory requirements of consumer markets increasingly importing and exporting countries have shown interest in food irradiation and conducted research in the practical application of this technology and detection methods of treatment. Numerous surveys were conducted worldwide, resulting in efficient protocols to identify which foods were irradiated or not. Until then, the \"myth\" that irradiated food could not be detected and they were not formed any single radiation products has been replaced by the knowledge that many changes can occur in irradiated foods and these changes could be used as tools to identify this technology. The radiation processing resulting in characteristic patterns formations of saturated hydrocarbons, aldehydes, methyl and ethyl esters and 2-alcilciclobutanonas, depending on the fatty acid composition of the lipid that composes the food. Thus the purpose of this study was to collect data to compare the effects of different doses of gamma radiation and electron in foods that have fat to determine possible changes resulting from the use of irradiation, as the presence of 2-Alcilciclobutanonas and also show main equipment used for food irradiation and its categories, with the aim of informing the general public.

As cianobactérias pertencem a um grupo de organismos que surgiram no planeta há cerca de 3,5 bilhões de anos. Durante 270 milhões de anos elas dominaram, em um período que ficou conhecido como o Período das Cyanophyceae (Pré-Cambriano). Águas eutrofizadas oferecem os requisitos para haver floração aumentando as chances estatísticas de aparecimento de cianobactérias, inclusive as tóxicas. Há alteração substancial das características das comunidades e do ecossistema e, por seu potencial tóxico, esses organismos causam conseqüências danosas à integridade ambiental e à saúde pública. Essas florações são resultado da interação de fatores físicos, químicos e bióticos, evidenciados por crescimento explosivo - florações - de poucas espécies, freqüentemente as menos exigentes a gás carbônico. Entre as cianobactérias formadoras de florações destacam-se os gêneros: Aphanizomenon sp., Oscillatoria sp., Anabaena sp., Microcystis sp., Gloeotrichia sp., Cylindrospermospsis sp. e Nodularia sp. Entre as cianobactérias produtoras de toxinas destacam-se as espécies: Anabaena flos-aquae, Microcysits aeruginosa, Aphanizomenon flos-aquae, Oscillatoria agardhii, Cylindrospermopsis raciborskii e Nodularia spumigena. O problema para a saúde pública e ambiental relaciona-se à liberação das toxinas que sempre ocorre após a lise celular, devido ao uso de algicidas, ao estresse celular ou à senescência. As cianotoxinas - neurotoxinas, hepatotoxinas, endotoxinas (lipopolissacarídeos) - não causam os mesmos efeitos nos diferentes organismos que as ingerem. Para análises quantitativas e qualitativas das amostras fitoplanctônicas são necessárias rotinas laboratoriais, que têm início desde a coleta, estocagem, sedimentação e identificação das espécies ao microscópio. Em câmaras de sedimentação apropriadas é possível contar e identificar os organismos em questão. O volume celular é estimado por meio de formas geométricas, correspondentes às dimensões celulares dos organismos. O carbono orgânico e os pigmentos fotossintetizantes, principalmente a clorofila a, fornecem indicação da biomassa fitoplanctônica. A extração desta pode ser feita utilizando-se acetona, etanol ou metanol. Os métodos mais usados para determinação da concentração de clorofila a são: fluorimetria, espectrofotômetria e HPLC, este último o método mais preciso. No Brasil têm sido registradas ocorrências de florações de cianobactérias e a preocupação tem aumentado significamente após o caso de Caruaru (PE). Como é difícil prever as florações de cianobactérias potencialmente tóxicas, alguns métodos laboratoriais, como bioensaios, HPLC, CG, ELISA, Inibição de Fosfatase e Inibição de Acetilcolinesterase têm sido de grande ajuda na determinação das cianotoxinas, o que possibilita que as empresas abastecedoras de água tomem as providências cabíveis, quanto ao abastecimento da população e cumprimento da Portaria 518, de 24 de março de 2004. No entanto a Portaria nº 518 do Ministério da Saúde mostra-se ineficaz pela falta de artigos sobre o gerenciamento dos corpos hídricos eutrofizados, que mostram alterações em suas características e que podem ser associados a problemas de saúde pública, e também pela falta de penalidades e outras sanções (exemplo: fiscalização) que auxiliem no cumprimento da legislação. Devido a isso, procedimentos e profissionais devem ser encontrados e treinados para o entendimento de como, onde e por que, as florações acontecem. / Cyanobacteria are part of a group of organisms that have had a long evolutionary history extending to at least 3,5 billion years ago. During 270 million years they had been dominant, in a period that was known as the \"Age of Cyanophyceae\" (Early Cambrian Period or Proterozoic Era). Eutrophic waters offer the requirements for the blooms increasing statistically the chances of cyanobacteria emergence, including the toxic ones. There is substantial disturbance of characteristics of the communities and ecosystem and, because of their toxic potential, those organisms cause harmful consequences to the environmental integrity and public health. Those blooms are a result of an interaction of physical, chemical and biotic factors, evidenced by the proliferation of few species, frequently the least demanding ones to carbonic gas. Globally among the most frequently found freshwater cyanobacteria forming water-blooms it must be emphasized the following strains: Aphanizomenon sp., Oscillatoria sp., Anabaena sp., Microcystis sp., Gloeotrichia sp., Cylindrospermospsis sp. and Nodularia sp. Among the cyanobacteria producing toxins it must be emphasized the following species: Anabaena flos-aquae, Microcysits aeruginosa, Aphanizomenon flos-aquae, Oscillatoria agardhii, Cylindrospermopsis raciborskii and Nodularia spumigena. Environmental and public health problems are largely associated with the release of toxins occurring after cellular lisys, caused by the use of algicides, cell stress or senescence. Cyanotoxins - neurotoxins, hepatotoxins, endotoxins (lipopolysaccharides) - cause distinct effects in the different organisms ingesting them. For quantitative and qualitative analyses of phytoplanktonic samples they are necessary laboratory routines as collection, stocking, sedimentation and identification of the species performed by microscopic examination. It is possible to count and identify such organisms in appropriate sedimentation chambers. Cell volumes are calculated for each species from formulae for solid geometric shapes that most closely match the cell shape based on cell dimensions. Organic carbon and photosynthetic pigments primarily chlorophyll-a are used to estimate the biomass of the phytoplankton. Chlorophyll-a extraction can be made by using acetone, ethanol or methanol. The major methods used for determination of chlorophyll-a concentrations are fluorometry, spectrophotometry and HPLC. In particular, HPLC has been considered the most accurate analytical method. Occurrences of cyanobacteria blooms in Brazil have been recorded, and a concern has becoming increasingly significant after the Caruaru (PE) episode. It is difficult to foresee the potentially toxic cyanobacteria blooms, so some laboratory methods as Bioassays, HPLC, CG, ELISA, Inhibition of Phosphatase and Inhibition of Acetylcholinesterase have been of great help in the determination of the cyanotoxins, what permits that the health authorities take reasonable providences related to drinking water supplies and fulfill the Guideline 518, of March 24, 2004. Nevertheless, national legislation becomes inefficient by the lack of ordinances about the management of eutrophic water bodies, which may notably alter the characteristics of aquatic ecosystems and cause public health problems. Penalties and other sanctions to assist in enforcement of the legislation are also needed. Procedures must be taken and operators must be trained in order to clarify how, where and why blooms happen.

The cost of adverse drug reactions to society in the form of deaths, chronic illness, foetal malformation, and many other effects is quite significant. For example, in the United States of America, adverse reactions to prescribed drugs is around the fourth leading cause of death. The reporting of adverse drug reactions is spontaneous and voluntary in Australia. Many methods that have been used for the analysis of adverse drug reaction data, mostly using a statistical approach as a basis for clinical analysis in drug safety surveillance decision support. This thesis examines new approaches that may be used in the analysis of drug safety data. These methods differ significantly from the statistical methods in that they utilize co variability methods of association to define drug-reaction relationships. Co variability algorithms were developed in collaboration with Musa Mammadov to discover drugs associated with adverse reactions and possible drug-drug interactions. This method uses the system organ class (SOC) classification in the Australian Adverse Drug Reaction Advisory Committee (ADRAC) data to stratify reactions. The text categorization algorithm BoosTexter was found to work with the same drug safety data and its performance and modus operandi was compared to our algorithms. These alternative methods were compared to a standard disproportionality analysis methods for signal detection in drug safety data including the Bayesean mulit-item gamma Poisson shrinker (MGPS), which was found to have a problem with similar reaction terms in a report and innocent by-stander drugs. A classification of drug terms was made using the anatomical-therapeutic-chemical classification (ATC) codes. This reduced the number of drug variables from 5081 drug terms to 14 main drug classes. The ATC classification is structured into a hierarchy of five levels. Exploitation of the ATC hierarchy allows the drug safety data to be stratified in such a way as to make them accessible to powerful existing tools. A data mining method that uses association rules, which groups them on the basis of content, was used as a basis for applying the ATC and SOC ontologies to ADRAC data. This allows different views of these associations (even very rare ones). A signal detection method was developed using these association rules, which also incorporates critical reaction terms. / Doctor of Philosophy

The cost of adverse drug reactions to society in the form of deaths, chronic illness, foetal malformation, and many other effects is quite significant. For example, in the United States of America, adverse reactions to prescribed drugs is around the fourth leading cause of death. The reporting of adverse drug reactions is spontaneous and voluntary in Australia. Many methods that have been used for the analysis of adverse drug reaction data, mostly using a statistical approach as a basis for clinical analysis in drug safety surveillance decision support. This thesis examines new approaches that may be used in the analysis of drug safety data. These methods differ significantly from the statistical methods in that they utilize co variability methods of association to define drug-reaction relationships. Co variability algorithms were developed in collaboration with Musa Mammadov to discover drugs associated with adverse reactions and possible drug-drug interactions. This method uses the system organ class (SOC) classification in the Australian Adverse Drug Reaction Advisory Committee (ADRAC) data to stratify reactions. The text categorization algorithm BoosTexter was found to work with the same drug safety data and its performance and modus operandi was compared to our algorithms. These alternative methods were compared to a standard disproportionality analysis methods for signal detection in drug safety data including the Bayesean mulit-item gamma Poisson shrinker (MGPS), which was found to have a problem with similar reaction terms in a report and innocent by-stander drugs. A classification of drug terms was made using the anatomical-therapeutic-chemical classification (ATC) codes. This reduced the number of drug variables from 5081 drug terms to 14 main drug classes. The ATC classification is structured into a hierarchy of five levels. Exploitation of the ATC hierarchy allows the drug safety data to be stratified in such a way as to make them accessible to powerful existing tools. A data mining method that uses association rules, which groups them on the basis of content, was used as a basis for applying the ATC and SOC ontologies to ADRAC data. This allows different views of these associations (even very rare ones). A signal detection method was developed using these association rules, which also incorporates critical reaction terms. / Doctor of Philosophy