Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (p. 127-137).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1984. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 211-215).

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains xv, 99 p.; also includes graphics (some col.). Includes bibliographical references (p. 95-99). Available online via OhioLINK's ETD Center

Thesis (Ph. D.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains v, 218 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references.

Dentre as diversas aplicações dos radioisótopos, a utilização dos radiotraçadores é considerada uma das mais importantes, no diagnóstico de funcionamento dos equipamentos de processos, em plantas de indústrias químicas e petroquímicas. Os radiotraçadores são utilizados em procedimentos analíticos para obtenção de dados qualitativos e quantitativos de sistemas, em estudos de transferências físicas e físico-químicas. Na produção de radioisótopos gasosos utilizados como traçadores em processos industriais, destacam-se o 41Ar e 79Kr, gases nobres (inertes) que possuem baixa reatividade com os demais elementos químicos. O 41Ar é um emissor gama de alta energia (1,29 MeV) e apresenta elevada porcentagem de transformações com essa energia, o que resulta em quantidades relativamente pequenas necessárias em relação a outras para uma detecção eficaz, mesmo em componentes com grandes espessuras. Atualmente, a produção de radioisótopos gasosos em reatores nucleares de pesquisa é realizada em pequenas quantidades (bateladas), por meio de ampolas de quartzo contendo o gás natural 40Ar ou 78Kr. Nesse sentido, o objetivo desse estudo é desenvolver um sistema de irradiação capaz de produzir em escala contínua, o radioisótopo gasoso 41Ar, dentre outros, com atividade de 7,4x1011 Bq (20 Ci) por ciclo de irradiação, por meio do Reator IEA-R1 de 4,5 MW, fluxo de nêutrons térmicos médio de 4,71 x 1013 ncm-2s-1, para suprir uma demanda existente em empresas de END e inspeções, e pelo próprio Centro de Tecnologia das Radiações, no IPEN/CNEN-SP. O sistema de irradiação (SI) é constituído por uma cápsula de irradiação em alumínio, linhas de transferência, válvulas agulhas, conexões anilhadas, conectores rápidos, manovacuômetro, sistema de vácuo, dewar de liquefação, blindagem em chumbo, cilindros de armazenamento e transporte (CAT), dentre outros. O SI foi aprovado nos testes de estanqueidade e estabilidade (testes de formação de bolhas, pressurização, evacuação e com equipamento leak detector SPECTRON 600 T). Na produção experimental para obtenção de 1,07x1011 Bq (2,9 Ci) de 41Ar, distribuíram-se dosímetros de alanina em diversos componentes e dispositivos do SI. Além disso, determinaram-se as taxas de exposição na parede da blindagem em chumbo, ao concentrar o gás radioativo liquefeito e no CAT, após a transferência do 41Ar, pelo medidor de radiação portátil Teletector ® Probe 6150 AD-t/H. / Among the various applications of radioisotopes, the use of radiotracers is considered the most important in diagnosing operation and troubleshooting of industrial process plants in chemical and petrochemical companies. The radiotracers are used in analytical procedures to obtain qualitative and quantitative data systems, in physical and physicochemical studies transfers. In the production of gaseous radioisotopes used as tracers in industrial process measurements, argon-41 (41Ar) and krypton-79 (79Kr) have low reactivity with other chemical elements. 41Ar is a transmitter range with high-energy (1.29MeV) and a high percentage of this energy transformation (99.1%), resulting in relatively small quantities required in relation to the other, for an efficient detection, even in large thicknesses components. Nowadays, the production of gaseous radioisotopes in nuclear research reactors is performed in small quantities (batches), through quartz ampoules containing natural gas 40Ar or 78Kr. In this sense, the aim of this study is to develop an irradiation system for gaseous radioisotope production in continuous scale, applied in industrial applications of emission tomography and flow measurement. The irradiation system may produce 41Ar with activity of 7.4x1011Bq (20Ci) per irradiation cycle, through the Reactor IEA-R1 with 4.5MW and average thermal neutron flux of 4.71x1013 ncm-2s-1 to meet an existing demand in NDT and inspections companies, and even needed by the Radiation Technology Centre, at IPEN/CNEN-SP. The irradiation system consists of an aluminium irradiation capsule, transfer lines, needle valves, stripy connections, quick connectors, manometer, vacuum system, dewar, lead shielding, storage and transport cylinders, among other components. The irradiation system was approved in the leakage and stability tests (bubble test, pressurization, evacuation and with leak detector equipment SPECTRON 600 T). In the experimental production, alanine dosimeters were distributed into various components of the irradiation system, obtaining 1.07x1011Bq (2.9Ci) of 41Ar. In addition, exposure rates were determined in the lead shielding wall, in which the liquefied radioactive gas was concentrated, and in the storage and transport cylinders after 41Ar was transferred, by the portable radiation meter Teletector ® Probe 6150 AD-t/H.

Memoria para optar al Título Profesional de: Ingeniera Agrónoma / Investigaciones recientes han evaluado el uso de gases no convencionales con propiedades únicas que podrían ayudar a disminuir la perecibilidad de los alimentos. El objetivo de esta investigación fue evaluar el efecto de atmósferas enriquecidas con argón (90% Ar + 10% O2), helio (90% He + 10% O2), óxido nitroso (90% N2O + 10% O2) y oxígeno (100% O2) sobre la calidad de germinados de soya conservadas durante 12 días a 5 °C, bajo atmósfera modificada activa en envases plásticos con una permeabilidad de 9000 mL CO2 m-2 d-1 y de 3000 mL O2 m-2 d-1 (San Jorge Packaging, Chile). Los parámetros evaluados fueron tasa respiratoria, producción de etileno, concentración de gases al interior del envase, color, evaluación sensorial, concentración de compuestos fenólicos, capacidad antioxidante, concentración de azúcares y vitamina C. La tasa respiratoria de los germinados de soya presentó valores en un rango de 42,1 a 78,1 mg CO2 kg-1 h-1 el día del procedimiento que luego se redujo por efecto de los gases no convencionales, oscilando en un rango de 20,1 a 27,7 mg CO2 kg-1 h-1 tras 12 días de almacenamiento. En cuanto a la composición gaseosa de los tratamientos con gases no convencionales, hubo un aumento en la concentración de CO2, tras el primer día de almacenamiento presentó valores de 0,4 a 0,6% de CO2 que luego de 12 días de almacenamiento presentó de 1,9 a 4,2% de CO2. Referente a las características sensoriales, las atmósferas lograron mantener los germinados de soya en un nivel aceptable durante toda la conservación, con valores significativamente más altos que el tratamiento aire al día 12. El color no fue afectado por los tratamientos a lo largo de la conservación. Con los resultados obtenidos en este experimento se recomiendan por igual los gases Ar, He, N2O. Ninguno de los gases en evaluación generó sabores extraños. Además, todos los tratamientos mantuvieron la calidad funcional, en tanto a los compuestos fenólicos totales presentaron valores de 1,7 a 3,1 mg EAG g-1 pf, respecto a la capacidad antioxidante tuvo valores de 50,4 a 76,1 mg Trolox g-1 pf. / Recent research has evaluated the use of unconventional gases with unique properties that may help reduce the perishability of food. The objective of this research was to evaluate the effect of argon-enriched atmospheres (90% Ar + 10% O2), helium (90% He + 10% O2), nitrous oxide (90% N2O + 10% O2) and oxygen (100 % O2) on the quality of soybean sprouts stored 12 days at 5 ° C active modified atmosphere in plastic containers with a permeability of 9000 mL CO2 m-2 d-1 and 3000 mL O2 m-2 d-1 (San Jorge Packaging, Chile). The parameters evaluated were respiration rate, ethylene production, concentration of gases into the packages, color, sensory quality, total phenolic compounds, antioxidant capacity, sugars and vitamin C contents. Respiration rate of the bean sprouts have values in a range of 42,1 to 78,1 mg CO2 kg -1 h -1 on the process which is then reduced by the effect of non-conventional gases , oscillating in a range of 20,1 to 27,7 mg CO2 kg -1 h -1 after 12 days of storage. Regarding the gas composition of gases conventional treatments, there was an increased CO2 concentration, after the first day of storage showed levels of 0,4 to 0,6 % CO2 after 12 days of storage showed from 1,9 to 4,2% CO2. Regarding sensory characteristics, atmospheres managed to maintain soybean sprouts at an acceptable level for all conservation, with values significantly higher than air treatment at day 12. The color was not affected by the treatments over conservation. With the results obtained in this experiment are recommended equally gases Ar, He, N2O. None of the gases generated in evaluating flavors. Furthermore, all treatments remained functional quality, while a total phenolic compounds had values of 1,7 to 3,1 mg EAG g- 1 pf, regarding the antioxidant had values from 50,4 to 76,1 mg Trolox g- 1 pf .

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Made available in DSpace on 2014-10-09T12:49:37Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:17Z (GMT). No. of bitstreams: 1 10001.pdf: 4508519 bytes, checksum: 65261fff2e8d34992f8d1c3a0d09b0d3 (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo