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Thesis. (M. Tech (Biotechnology, Faculty of Applied and Computer Science))--Vaal University of Technology, 2011. / Bottled water like any drinking water used for human consumption should be safe and wholesome to ensure adequate public health protection. This is due to potential health effects of concern such as endocrine disruption, toxicity teratogenicity, mutagenicity and carcinogenicity. Despite the number of regulatory bodies, publications on bottled water and speculations on its public health significance, many questions remain to be answered. One of the questions is whether the shelf life of bottled water is a cause for concern. The aim of the study was to determine the shelf-life of various commercial bottled waters by monitoring the variation in microbiological, chemical and aesthetic qualities of bottled water. A total of five commercial bottled water brands (A, B, C, D, E) each containing bottles from the same batch consisting of spring water, mineral water and bottled tap water were purchased directly after being bottled from different distributors around Gauteng in South Africa. All samples were stored at room temperature with artificial lighting and controlled temperature for a year thus mimicking typical conditions in retail outlets, supermarkets and in homes. Analyses were conducted over a period of 12 months, at monthly intervals. Within days of being purchased, high Heterotrophic plate counts (HPC) bacteria exceeding drinking water alert level >5 000 cfu/ml was common in four bottled water brands. Growth succession occurred during the period of study as various algal species were growing and accumulating on all bottled water tested. Total coliforms (TC), faecal coliforms (FC) and E.coli were not detected in all the bottled water tested. Yeasts and moulds were also not detected in all the bottled water. There were insignificant variations during the period of study for turbidity, pH, TDS, conductivity, and colour. These did not indicate any potential impact on aesthetic quality of bottled water. Two bottled water brands had hardness measures as low as 11mg/ℓ as CaCO3 making the water too soft which has an effect on taste. Radioactive substances, trihalomethanes, heavy metals, pesticides and other chemical contaminants were not found at levels that can be detrimental to human health.

Made available in DSpace on 2016-04-28T14:16:39Z (GMT). No. of bitstreams: 1 Sonia Regina Tonetto.pdf: 626804 bytes, checksum: c63e9e43e4f66f52141b6a21a0d3e6ce (MD5) Previous issue date: 2009-05-13 / Secretaria da Educação do Estado de São Paulo / The object of analysis of this study is the first biography of Madame Curie, written by her daughter Eve Curie. This book portrays the historical period, family life and the rise of the professional scientist. The first chapter reviews the author's intent in building the image of the biographied. The expressions used, the chosen facts to be portrayed. The selected correspondence is also analyzed as part of building of this image. In the second chapter, the works of Eulália Sedeño Peres and Margaret W. Rossiter are used as reference to analyze both, the path followed by the scientist and her strategies. The attitudes and reactions of Mme. Curie, facing different situations and in different periods are analyzed in the scientist's correspondence with family and friends and other events in the life of the scientist that don t appear in the biography written by her daughter. The third chapter discusses the work of the scientist in the laboratory. The working conditions, the equipment developed by Pierre Curie, some factors that led the scientist to focus her studies on radioactive materials and the consequences of that choice. Moreover, facts reported are discussed in biography written by Eve Curie and others that were missing and could blacken her image. Thus, the analysis of the biography written by Eve Curie, other biographies and subsequent studies carried on the work of Mme Curie, show the importance of the biography for the History of the Science and the intent of the biographer to write about the history of a scientist / O objeto de análise deste estudo é a primeira biografia sobre Mme Curie, escrita por sua filha Eve Curie. Esta obra retrata o período histórico, a vida familiar e a ascensão profissional da cientista. No primeiro capítulo é analisada a intencionalidade da autora na construção da imagem da biografada. As expressões utilizadas, os fatos escolhidos para serem retratados. A correspondência selecionada também é analisada como parte da construção dessa imagem. No segundo capítulo as obras de Eulália Peres Sedeño e Margaret W. Rossiter são utilizadas como referência para analisar tanto o caminho seguido pela cientista quanto suas estratégias. As atitudes e reações de Mme. Curie, diante de diferentes situações e em diversos períodos, são analisados nas correspondências da cientista com familiares e amigos, além de outros fatos ocorridos na vida da cientista e que não aparecem na biografia escrita por sua filha. O terceiro capítulo aborda o trabalho da cientista no laboratório. As condições de trabalho, os equipamentos desenvolvidos por Pierre Curie. Alguns fatores que levaram a cientista a focalizar seus estudos nos materiais radioativos e as conseqüências dessa escolha. Além disso, são discutidos fatos relatados na biografia escrita por Eve Curie e outros que foram omitidos e poderiam denegrir sua imagem. Dessa forma, a análise da biografia escrita por Eve Curie, de outras biografias posteriores e dos estudos desenvolvidos sobre o trabalho de Mme Curie, mostrará a importância da biografia para a História da Ciência, além de pontuar a intencionalidade do biógrafo ao escrever sobre a história de um cientista

In the following work, the MAVRIC sequence of the Scale6.1 code package was tested for its efficacy in calculating a wide range of shielding parameters with respect to HTGRs. One of the NGNP designs that has gained large support internationally is the VHTR. The development of the Scale6.1 code package at ORNL has been primarily directed towards supporting the current United States' reactor fleet of LWR technology. Since plans have been made to build a prototype VHTR, it is important to verify that the MAVRIC sequence can adequately meet the simulation needs of a different reactor technology. This was accomplished by creating a detailed model of the VHTR power plant; identifying important, relevant radiation indicators; and implementing methods using MAVRIC to simulate those indicators in the VHTR model. The graphite moderator used in the design shapes a different flux spectrum than water-moderated reactors. The different flux spectrum could lead to new considerations when quantifying shielding characteristics and possibly a different gamma-ray spectrum escaping the core and surrounding components. One key portion of this study was obtaining personnel dose rates in accessible areas within the power plant from both neutron and gamma sources. Additionally, building from professional and regulatory standards a surveillance capsule monitoring program was designed to mimic those used in the nuclear industry. The high temperatures were designed to supply heat for industrial purposes and not just for power production. Since tritium, a heavier radioactive isotope of hydrogen, is produced in the reactor it is important to know the distribution of tritium production and the subsequent diffusion from the core to secondary systems to prevent contamination outside of the nuclear island. Accurately modeling indicators using MAVRIC is the main goal. However, it is almost equally as important for simulations to be carried out in a timely manner. MAVRIC uses the discrete ordinates method to solve the fixed-source transport equation for both neutron and gamma rays on a crude geometric representation of the detailed model. This deterministic forward solution is used to solve an adjoint equation with the adjoint source specified by the user. The adjoint solution is then used to create an importance map that can weight particles in a stochastic Monte Carlo simulation. The goal of using this hybrid methodology is to provide complete accuracy with high precision while decreasing overall simulation times by orders of magnitude. The MAVRIC sequence provides a platform to quickly alter inputs so that vastly different shielding studies can be simulated using one model with minimal effort by the user. Each separate shielding study required unique strategies while looking at different regions in the VHTR plant. MAVRIC proved to be effective for each case.

This doctoral study consists of two parts. In the first part, the quantum statistical effects on the formation process of the heavy ion fusion reactions have been investigated by using the c-number quantum Langevin equation approach. It has been shown that the quantum effects enhance the over-passing probability at low temperatures. In the second part, we have developed a simulation technique for the quantum noises which can be approximated by two-term exponential colored noise.

The pseudospin symmetry concept is investigated by solving the Dirac equation for the exactly solvable potentials such as pseudoharmonic potential, Mie-type potential, Woods-Saxon potential and Hulth&eacute / n plus ring-shaped potential with any spin-orbit coupling term $kappa$. Nikiforov-Uvarov Method, Asymptotic Iteration Method and functional analysis method are used in the calculations. The energy eigenvalue equations of the Dirac particles are found and the corresponding radial wave functions are presented in terms of special functions. We look for the contribution of the ring-shaped potential to the energy spectra of the Dirac particles. Particular cases of the potentials are also discussed. By considering some particular cases, our results are reduced to the well-known ones presented in the literature. In addition, by taking equal mixture of scalar and vector potentials together with tensor potential, solutions of the Dirac equation are found and then the energy splitting between the two states in the pseudospin doublets is investigated. We indicate that degeneracy between members of pseudospin doublet is removed by tensor interactions. Effects of the potential parameters on the pseudospin doublet splitting are also studied. Radial nodes structure of the Dirac spinor are presented.

Der Bericht informiert über die Ergebnisse der Auswertung von aerogammaspektrometrischen Befliegungen der Gebiete des ehemaligen Uranerzbergbaus im Freistaat Sachsen in den Jahren 1982 bis 2010. Die Ergebnisse der Datenauswertung zeigen eine übersichtsmäßige Darstellung des Sanierungsfortschrittes an den ehemaligen Uranbergbaustandorten Aue, Johanngeorgenstadt und Zwickau bis zum Jahr 2010 anhand von interpolierten Kartendarstellungen für die Parameter Uran, Thorium und Gamma-Ortsdosisleistung (ODL). Die Veröffentlichung richtet sich sowohl an das Fachpublikum als auch an naturwissenschaftlich interessierte Laien.

Nowadays we are all witnesses of a competition of facilities at different countries to study unknown regions of neutron rich nuclei. Much efforts are devoted to understand the role of neutron excess and its influence on nuclei in vicinity of closed neutron shells. One of the means to investigate nuclear structure is in beta-decay. Once a nucleus is proven to exist, its beta-decay properties, such as T1/2 and Pn (probability of beta-delayed neutron emission), which are relatively easy to measure, can provide the first hints on the nuclear structure. On the r-process site, "waiting points"(nuclei on closed neutron shells) has significant effects on the r-process dynamics and the abundance distribution. The actual side and the astrophysical conditions under which the nuclear synthesis takes place are still not certainly known - since r-process nuclei are difficult to produce and to study experimentally, input parameters for r-process calculations are mostly derived from theoretical models. As it has been seen lately, most of the theories have failed to reproduce newly measured data sets near shell closures. With new experimental data already (or shortly) available theoretical approaches can be adjusted. Since a beta-delayed neutron emission becomes strong if not dominating decaying channel for nuclei far stability, a proper neutron detector to study their properties is indispensable. To conduct the appropriate investigations, in the frame of the present thesis, in close collaboration with JINR (Dubna) a new detection system was constructed. It consists of 80 ³He-filled counters, 4π beta detector and a HPGe in order to measure simultaneously beta, gamma, neutron activity. The development of such a detection system system, currently installed at ALTO ISOL facility, was the first objective of the thesis. Then, during two experimental campaigns conducted to investigate beta decay properties of neutron rich nuclei in the neighborhood of N=50, N=82 the workability of the newly produced detection system was proven. In the vicinity of ⁷⁸Ni: half- lives and probability of beta-delayed neutron emission for ⁸º,⁸²,⁸³,⁸⁴Ga were measured. We were the first to observe the structure of ⁸¹,⁸² Ge via beta neutron gated gamma spectra. Thanks to the neutron detection channel the absolute intensities of beta decay were proposed for the first time. In the vicinity of ¹³²Sn the half lives of ¹²³Ag, ¹²⁴Ag, ¹²⁵Ag and ¹²⁷In, ¹²⁸In was measured. For the first time the beta delayed neutron emission was observed for ¹²⁶Cd, its Pn value also measured. Based on the data obtained we come to the conclusion that to figure out the relative contribution of allowed and forbidden decays more theoretical efforts should be done crossing the N=50 shell. Whereas in the vicinity of N=82 shell more experimental challenge are required.

L'étude des noyaux exotiques est un outil important pour sonder la structure nucléaire des noyaux éloignés de la stabilité. Pour des noyaux situés à la drip-line proton, l'émission directe de protons a été prédite depuis le début des années 1960. Ce travail de thèse est focalisé sur l'étude de la radioactivité 2-protons du noyau 45Fe. Un modèle théorique récent, dit modèle à trois corps, prévoit les corrélations énergétiques et angulaires qui doivent exister entre les protons émis. Afin d'étudier le processus d'émission, une Chambre à Projection Temporelle a spécialement été conçue pour reconstruire en trois dimensions la trajectoire des protons. Elle a été utilisée pendant une expérience sur le séparateur LISE3 du GANIL pour l'étude de 45Fe. Pour la première fois, les deux protons émis ont pu être détectés individuellement. Des outils d'analyse spécifiques ont permis de calculer les corrélations énergétiques entre les protons, montrant qu'ils partagent équitablement l'énergie disponible, tel que le prévoient les différents modèles théoriques. Les corrélations angulaires ont été étudiées, mais le manque de statistique ne permet pas de trancher définitivement sur le processus d'émission mis en jeu même si les données sont en accord avec les prévisions du modèle à trois corps. L'expérience a également permis d'étudier l'émission retardée de protons de 43Cr. L'émission beta-2p a été identifiée ; les corrélations énergétiques et angulaires sont en faveur d'une émission séquentielle des deux protons. Enfin, et pour la première fois, l'émission retardée de trois protons a été observée pour ce noyau.

This master's thesis is an investigation and evaluation of MELCOR (a software tool for severe accident analyses regarding nuclear power plants), or more correctly of the (ASEA-Atom BWR 75) reactor model developed for version 1.8.6 of MELCOR. The main objective was to determine if MELCOR, with the reactor model in question, is able to produce satisfactory results in severe accident analyses compared to results made by MAAP, which is currently the only official software tool for this application in Sweden. The thesis work is related to the RASTEP project. This project has been carried out in several stages on behalf of SSM since 2009, with a number of specific issues explored within an NKS funded R&D project carried out 2011-2013. This investigation is related to the NKS part of the project. The purpose with the RASTEP project is to develop a method for rapid source term prediction that could aid the authorities in decision making during a severe accident in a nuclear power plant. A software tool, which also gave the project its name, i.e. RASTEP (RApid Source TErm Prediction), is therefore currently under development at Lloyd's Register Consulting. A software tool for severe accident analyses is needed to calculate the source terms which are the end result from the predictions made by RASTEP. A set of issues have been outlined in an earlier comparison between MAAP and MELCOR. The first objective was therefore to resolve these pre-discovered issues, but also to address new issues, should they occur. The existing MELCOR reactor model also had to be further developed through the inclusion of various safety systems, since these systems are required for certain types of scenarios. Subsequently, a set of scenarios was simulated to draw conclusions from the additions made to the reactor model. Most of the issues (pre-discovered as well as new ones) could be resolved. However the work also rendered a set of issues which are in need of further attention and investigation. The overall conclusion is that MELCOR is indeed a promising alternative for severe accident analyses in the Swedish work with nuclear safety. Several potential benefits from making use of MELCOR besides MAAP have been identified. In conclusion, they would be valuable assets to each other, e.g. since deviations in the results (between the two codes) would highlight possible weaknesses of the simulations. Finally it is recommended that the work on improving the MELCOR reactor model should continue. / RASTEP