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The embrittlement of reactor pressure vessel (RPV) steels due to neutron irradiation restricts the operating lifetime of nuclear reactors. The reference temperature 𝑇0, obtained from fracture mechanics testing using the Master Curve concept, is a good indicator of the irradiation resistance of a material. The measurement of the shift in 𝑇0 after neutron irradiation, which accompanies the embrittlement of the material, using the Master Curve concept, enables the assessment of the reactor materials. In the context of worldwide life time extensions of nuclear power plants, the limited availability of neutron irradiated materials (surveillance materials) is a challenge. Testing of miniaturized 0.16T C(T) specimens manufactured from already tested standard Charpy-sized specimens helps to solve the material shortage problem. In this work, four different reactor pressure vessel steels with different compositions were investigated in the unirradiated and in the neutron-irradiated condition. A total number of 189 mini-C(T) samples were fabricated and tested. An important component of this study is the transferability of fracture mechanics data from mini-C(T) to standard Charpy-sized specimen. Our results demonstrate good agreement of the reference temperatures from the mini-C(T) specimens with those from standard Charpy-sized specimens. RPV steels containing higher Cu and P contents exhibit a higher increase in 𝑇0 after irradiation. The fracture surfaces were investigated using SEM in order to record the location of the fracture initiators. The fracture modes were also determined. A large number of test results formed the basis for a censoring probability function, which was used to optimally select the testing temperature in Master Curve testing. The effect of the slow stable crack growth censoring criteria from ASTM E1921 on the determination of 𝑇0 was analysed and found to have a minor effect. Our results demonstrate the validity of mini-C(T) specimen testing and confirm the role of the impurity elements Cu and P in neutron embrittlement. We anticipate further research linking microstructure to the fracture properties of materials before and after neutron irradiation and the optimization of Master Curve testing using the results from our statistical analysis.

Plants and wildlife are being affected by climate change and human activities. We need to understand the patterns in these impacts to develop management strategies and policy solutions that will help us conserve ecosystems. Climate change is shifting the timing of key life stages in plants, but we do not fully understand the extent and implications of phenological shifts – or changes in the timing of seasonal events – for understudied stages like fruiting or for potential mismatches between plants in different canopy levels. Human activities and climate change impact and harm wildlife in many ways, from wildlife-vehicle collisions and lead poisoning to hurricanes and infectious diseases, but it has been difficult to form a comprehensive picture of these threats across many species and regions, and to discern which factors pose the greatest threat to at-risk species. Here, I collected and curated data from herbarium specimens and wildlife rehabilitation records to advance our understanding of the effects of climate change and human activities on plants and wildlife in North America. First, I found that metrics of first, peak, and last fruiting dates were strongly correlated between two historical datasets, suggesting that field observations and herbarium collections capture similar orders of fruiting times among plant species in New England. However, I found differences in the exact timing of first and last fruiting dates, indicating that researchers should match methodology when selecting historical records of phenology for present-day comparisons, especially when the exact timing is important. Next, I found that native trees, native shrubs, and non-native shrubs advanced their leaf-out or flowering times faster than native wildflowers advanced their flowering times with warming temperatures. As climate warming progresses, some native wildflower species, especially in warmer regions, are likely to be affected by phenological mismatch and lose access to early-season sunlight. Last, I found that human disturbances accounted for the largest proportion of wildlife injury and sickness in animals admitted to wildlife rehabilitation centers, and I identified the predominant reason for admittance for many species; these reasons included vehicle collisions, fishing incidents, and window or building collisions. I recommended possible interventions to help conserve wildlife, including using or changing wildlife road crossings, fishing and hunting regulations, lead and pesticide regulations, and disaster management plans. In this research, I compiled and analyzed innovative, newly-digitized data sources to provide new insights into the effects of climate change and human activities on plants and wildlife in North America. / 2024-09-18T00:00:00Z

Thesis (M. Tech.) - Central University of Technology, Free State, 2006 / Electron microscopy plays an important role in diagnostic histopathology. When this investigation is anticipated, extra tissue is submitted directly for electron microscopy. However, often it is decided only later in a problematic case to perform this investigation and then the only tissue available is embedded in the routine laboratory’s paraffin block. This tissue has to be retrieved from the wax and this entails using a clearing agent before the rest of the electron microscopy method can be implemented. Traditionally xylene is the agent that is used but has the disadvantage of being extremely toxic. This study compared the morphological effects of a relatively new and non toxic clearing agent, Tissueclear®, with that of xylene. Exposure of tissue to clearing agents for 30 minutes and overnight was performed to assess whether Tissueclear® gave better results in the long term than xylene, in the hope that the laboratory turn around time could be improved and the amount of toxic reagents used in the EM laboratory will be reduced. A second part of the study involved a questionnaire submitted to laboratory staff to assess their knowledge of xylene toxicity. Of the 325 cases submitted for electron microscopy at Universitas Hospital between January 2004 and July 2005, 140 of these had to be retrieved from paraffin wax. Four specimens were prepared from each case. Two were processed in xylene for 30 minutes and overnight and two in Tissueclear® for 30 minutes and overnight. The specimens were evaluated for consistency and resin compaction as well as ultrastructural preservation of the cell membrane, cytoplasmic content and extracellular material. The results showed that Tissueclear® and xylene gave comparable results after 30 minutes and that Tissueclear® was superior after overnight processing. This meant that a specimen submitted for electron microscopy would be processed immediately without waiting for the following morning as was the case with xylene and that the processing time for such a specimen had been shortened from 3 to 2 days. It also meant that the laboratory staff was exposed to one less toxic reagent. The results on the questionnaire showed that there were large areas of ignorance regarding toxicity as well as appropriate safety procedures that need to be followed in the laboratory. It is hoped that this study will improve awareness in this regard and encourage the use of other newer less toxic reagents.

Este trabalho apresenta o desenvolvimento de procedimentos para a medição de curvas de resistência J-R em espécimes SE(T) usando os métodos de flexibilidade elástica e método n. Uma descrição da metodologia sobre a qual J e o crescimento de trinca são medidos estabelece o contexto para determinar dados de resistência ao rasgamento dúctil com o emprego de curvas carga vs. deslocamento obtidas experimentalmente. A extensiva matriz de análises em estado plano de deformações de espécimes SE(T) complementada, em algumas geometrias selecionadas, com análises 3D permite a determinação numérica da flexibilidade adimensional, u, e fatores nJ e Y para uma grande faixa de proporções geométricas e propriedades de material características de aços estruturais e para dutos. Ensaios laboratoriais de um aço API 5L X60 à temperatura ambiente usando espécimes SE(T) carregados por pinos com entalhes laterais (side-grooves) fornecem os dados de carga e deslocamento necessários para validar o procedimento para determinar curvas de resistência do material. Os resultados apresentados nesta tese fornecem uma base de soluções para o futuro estabelecimento de norma padronizada para a medição experimental de curvas J-R em corpos de prova SE(T) mecanicamente similares a dutos com defeitos bidimensionais. / This work provides an estimation procedure to determine J-resistance curves for pinloaded and clamped SE(T) fracture specimens using the unloading compliance technique and the n-method. A summary of the methodology upon which J and crack extension are derived sets the necessary framework to determine crack resistance data from the measured load vs. displacement curves. The extensive plane-strain analyses and key 3D results enable numerical estimates of the nondimensional compliance, u , and parameters n and Y for a wide range of specimen geometries and material properties characteristic of structural and pipeline steels. Laboratory testings of an API 5L X60 steel at room temperature using pin-loaded SE(T) specimens with side-grooves provide the load-displacement data needed to validate the estimation procedure for measuring the crack growth resistance curve for the material. The results presented in the this thesis produce a representative set of solutions which lend further support to develop standard test procedures for constraint-designed SE(T) specimens applicable in measurements of crack growth resistance for pipelines.

Entre 1894 e 1916, período em que esteve sob a gestão do zoólogo Hermann von Ihering, o Museu Paulista conseguiu reunir coleções de dimensão considerável, que englobavam objetos pertinentes às diferentes disciplinas às quais a instituição se dedicava. Por meio dessas coleções, o Museu pôde produzir e veicular conhecimentos sobre a natureza e o homem sul-americano. Embora intrínsecos à prática da História Natural, a reunião e uso de coleções podem ser problematizados e investigados com algum grau de profundidade, trazendo à tona dimensões insuspeitas da história dos museus e das ciências naturais. Sendo assim, objetiva-se, nesta dissertação, investigar aspectos de processos de aquisição e uso de coleções de História Natural praticados no Museu Paulista de Ihering. Pretende-se, dessa forma, contribuir para a compreensão do que foram a implantação e o desenvolvimento do primeiro museu público do estado de São Paulo. Mais do que isso, almeja-se entender o papel central reservado aos espécimes científicos na produção e veiculação de conhecimentos sobre a natureza sul-americana. Para tanto, examinaremos as principais etapas envolvidas na curadoria das coleções: a aquisição de objetos, sua mobilização para produção de conhecimento e sua exibição no âmbito das exposições públicas / Between 1894 and 1916, the Museu Paulista was under the management of the zoologist Hermann von Ihering. During this period, the museum gathered collections of considerable size, which encompassed objects concerning to different disciplines. Through these collections, the Museum was able to produce and communicate knowledge about the nature and the man of South America. Gather and use collections are procedures intrinsic to the practice of Natural History. However, they may be deeply investigated, bringing out unsuspected dimensions of the history of museums and natural sciences. This dissertation aims to investigate the acquisition and use of collections of Natural History in the Museu Paulista of Ihering. We intend, therefore, to contribute to the understanding of the development of the first public museum in the state of São Paulo. More than that, we aim to understand the central role of scientific specimens in the production and communication of knowledge about the South American nature. To do so, we will examine the major steps involved in curating the collections: the acquisition of objects, its mobilization for the production of knowledge and its display in the public exhibitions. Keywords: material culture; collections; scientific specimens; Museu Paulista; Hermann von Ihering

<p>Everyday thousands of nurses are rendering bedside nursing care in health care settings as a result they are exposed to blood, body fluids and sharp objects that are contaminated with Hepatitis B, Hepatitis C and HIV. Therefore they are at risk of getting infected. In 1996, standard precautions were implemented by the Centre of Disease Control to reduce the risk of transmission of micro-organisms from any source of infection in the hospital. In the year 2008, the three tertiary hospitals together in the Western Cape reported that they had 733 needle prick injuries. Therefore the aim of the study was to determine if nurses comply with and have adequate knowledge of standard precautions. A non-experimental design and a self administered questionnaire were used to collect the data for the study. The study was done at Tygerberg Hospital and the participants (n=143) that were involved in the study were all nursing categories (professional, enrolled nurse and auxiliary nurse). Stratified random sampling was used to ensure that there was a representation of all the nurses working in the different modules at Tygerberg Hospital. Therefore three wards were randomly selected from each module and all the nurses on duty working in the three selected wards were given a questionnaire by the Assistant Director of the specific module. After the data was collected it was analysed through the statistical package for social sciences. The findings of the study showed that nurses have inadequate knowledge regarding standard precautions and the mean score of the nurses overall self reported compliance of standard precautions was 87.5%. The results also showed that when patients are HIV positive nurses intend to over comply the use of personal protective equipment. No association was found between the nurses&rsquo / knowledge and compliance regarding standard precautions. It is therefore important that every nurse should be educated about the basic principles of standard precautions and also the policies and protocols of infection control in order to prevent each nurse from getting infected. Training needs to be implemented starting in the wards through the unit manager to improve all the nurses&rsquo / knowledge and practice.</p>

Semi-circular specimens (SCB) under three point-bending which are commonly used for fracture testing of rocks were used here for fracture mechanics tests. A total of 65 specimens were tested by using Ankara andesite rock. Investigations including the effects of initial notch thickness, different loading span ratios (S/R), flattened loading end, and little dimensional variations when preparing the specimens were carried out. Stress intensity factors for specimens with different geometries were computed individually by using a 3D finite element program ABAQUS. Specimens with a preliminary notch thickness varying from 0.84 to 3.66 mm were tested under three point bending. For a second group of specimens loading span was changed and fracture toughness variation was studied. Another change in the specimen geometry was made by machining a flat loading end at the upper load application point. Fracture toughness values were computed using the stress intensity values computed from numerical modeling and failure loads from the experiments. It was found that up to 2 mm fracture toughness was not affected by variations in the thickness of preliminary notches. Fracture toughness was not affected by changing the loading span. For specimens with flat loading ends, fracture toughness was about 16% lower than the value found from regular SCB type specimens loaded at a point at the top by a steel roller. As a result of about 46 experiments average fracture toughness of Ankara G&ouml / lbasi andesite was found as 1.36 MPa .

The key character separating the dendrochirotid families Sclerodactylidae (sensu Pawson & Fell, 1965) and the Phyllophoridae (sensu Pawson & Fell, 1965), i.e. entire or undivided radial processes to the calcareous ring in the former and sub-divided processes in the latter, is unjustified since most sclerodactylid species also have subdivided processes. It is here assumed that the basis of elevating the subfamily Sclerodactylinae Panning to family level was established on a misinterpretation or mistranslation of the original diagnosis of this subfamily or a lapsus calumni meaning “plates” instead of “processes”. Panning (1949) categorically states that the processes in the Sclerodactylinae are composed of 3–4 large pieces of calcite and only as an exception they are unbroken. Since Pawson & Fell gave no other distinction between the Sclerodactylidae and the Phyllophoridae, the former is here considered an invalid taxon and its three current subfamilies (Sclerodactylinae, Sclerothyoninae Thandar and Cladolabinae Heding & Panning) are re-assigned to the Phyllophoridae. This family now includes six subfamilies: Cladolabinae, Phyllophorinae Östergren, Sclerodactylinae, Sclerothyoninae, Semperiellinae Heding & Panning and Thyoninae Panning. The diagnosis of the Sclerodactylinae, restricted by Thandar (1989), is now modified to include also those forms whose radial and interradial plates may be slightly sub-divided but still form a short tube. Of the eleven genera placed within this subfamily subsequent to its erection, only ten of these remain. Neothyone Deichmann is a preoccupied name for which Lisacucumis is here proposed as a replacement. Thandar’s (1989) diagnosis of the Thyoninae is here accepted, however, the genus Thorsonia Heding is transferred to the Sclerodactylinae. Of the 66 nominal species which currently stand in the “supergenus” Thyone Jaeger, 10 are transferred to Havelockia Pearson within the Sclerodactylinae, while one species is regarded as a synonym of H. herdmani Pearson. In addition, six species are transferred to Stolus Selenka within the Thyoninae. Finally, three species are transferred to Sclerothyoninae, two within Sclerothyone Thandar and one within Temparena Thandar. Two species show an uncertain affinity to Thyone and are temporally removed from the genus. Furthermore, two species currently classified within Havelockia are transferred to Thyone. The now remaining 46 species are separated into seven groups based on the composition of their introvert deposits: tables only (8 spp.), rosettes only (5 spp.), tables and rosettes (21 spp.), tables and plates/?reduced tables (2 spp.), rosettes and plates/?reduced tables (3 spp.), plates only (2 spp.), or introvert deposits absent or unknown (5 spp.). Regrettably, no other character could be used in conjunction with the above to suggest at least sub-generic levels. Within the genus Havelockia, Cucumaria redimita Sluiter indicates an affinity with Pentamera Ayres. It is here transferred to this genus within the Thyoninae. Havelockia, now containing 17 species, is also revised. Keys, diagnoses and figures are provided for all nominal species now included in Thyone and Havelockia. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2011.

<p>Everyday thousands of nurses are rendering bedside nursing care in health care settings as a result they are exposed to blood, body fluids and sharp objects that are contaminated with Hepatitis B, Hepatitis C and HIV. Therefore they are at risk of getting infected. In 1996, standard precautions were implemented by the Centre of Disease Control to reduce the risk of transmission of micro-organisms from any source of infection in the hospital. In the year 2008, the three tertiary hospitals together in the Western Cape reported that they had 733 needle prick injuries. Therefore the aim of the study was to determine if nurses comply with and have adequate knowledge of standard precautions. A non-experimental design and a self administered questionnaire were used to collect the data for the study. The study was done at Tygerberg Hospital and the participants (n=143) that were involved in the study were all nursing categories (professional, enrolled nurse and auxiliary nurse). Stratified random sampling was used to ensure that there was a representation of all the nurses working in the different modules at Tygerberg Hospital. Therefore three wards were randomly selected from each module and all the nurses on duty working in the three selected wards were given a questionnaire by the Assistant Director of the specific module. After the data was collected it was analysed through the statistical package for social sciences. The findings of the study showed that nurses have inadequate knowledge regarding standard precautions and the mean score of the nurses overall self reported compliance of standard precautions was 87.5%. The results also showed that when patients are HIV positive nurses intend to over comply the use of personal protective equipment. No association was found between the nurses&rsquo / knowledge and compliance regarding standard precautions. It is therefore important that every nurse should be educated about the basic principles of standard precautions and also the policies and protocols of infection control in order to prevent each nurse from getting infected. Training needs to be implemented starting in the wards through the unit manager to improve all the nurses&rsquo / knowledge and practice.</p>