Indiana University School of Dentistry located on the campus of Indiana University-Purdue University Indianapolis (IUPUI) / This in-vitro, prospective, randomized study microscopically compared the debridement efficacy of negative pressure irrigation with the EndoVac (Discus Dental, Culver City, CA) versus the Canal CleanMax (Maximum Dental, Inc., Secaucus, NJ). Sixty extracted human canines were instrumented using a combination of hand-instrumentation with Lexicon K-type files and rotary instrumentation with ProTaper files. All canals were irrigated with 6.0-percent sodium hypochlorite and 17- percent ethylenediaminetetraacetic acid (EDTA). However, the irrigation/aspiration techniques differed among three groups of 20 randomly selected teeth. Group one (control) was irrigated with only a 12-ml Monoject syringe via 30-gauge side-vented, closed-end needle. Group two was irrigated with the EndoVac system. Group three was irrigated similar to group one, but with the adjunct of the Canal CleanMax system. All teeth were sectioned longitudinally, and the more intact sections were divided into coronal, middle, and apical thirds. Each portion of the canal was photographed with a scanning electron microscope (SEM). The photographs were scored by two independent examiners according to relative amount of debris and/or smear layer present, as well as relative number of patent dentinal tubules. These scores were statistically analyzed using a Krustal-Wallis test and Wilcoxon Rank Sum tests to determine differences between groups. The coronal aspect of root canal walls irrigated with the EndoVac system exhibited significantly less debris and/or smear layer present when compared to the coronal aspect of root canals irrigated with only a standard 12-ml Monoject syringe equipped with 30-gauge ProRinse side-vented, closed-end needle (control). There were no other significant differences in scores between any groups at any location. For all locations combined, the EndoVac system produced significantly cleaner root canal walls as compared to the control. No significant differences were seen between the Canal CleanMax and Control or Canal CleanMax and EndoVac. This study suggested negative pressure irrigation delivery with the EndoVac system during and after hand-rotary instrumentation is more effective in removal of debris and smear layer from the coronal third and combined thirds of root canal walls compared to irrigation with a standard 12-ml Monoject syringe equipped with 30-gauge ProRinse side-vented, closed-end needle.

No description available.

O chumbo é um metal muito tóxico e que tem ampla distribuição pela sua grande utilidade. Mesmo a exposição a baixos níveis (que não causam sintomas de intoxicação aguda) de chumbo é associada a desordens cognitivas e neurológicas. O osso é considerado o melhor marcador de exposição a chumbo. No tecido ósseo, vários elementos estão presentes, e alguns deles poderiam ter sua concentração modificada pela exposição a chumbo. Testou-se a hipótese de que haja variações nos elementos Zn e Mg nas tíbias de animais expostos a chumbo (por técnica de química analítica convencional). Testou-se também se variações em microelementos poderiam ser detectadas por técnicas semiquantitativas nas tíbias de controles e animais expostos a chumbo. O objetivo deste projeto foi caracterizar em animais expostos ao chumbo desde a gestação e controles as concentrações deste elemento no osso (tíbia) de animais de 28 e 60 dias. Além do chumbo, investigamos também a concentração de 2 outros microelementos no osso: zinco e magnésio. As medidas quantitativas de chumbo foram feitas no sangue total coletado ao final dos períodos. As medidas quantitativas de chumbo, cálcio, zinco e magnésio foram realizadas a partir de soluções ácidas obtidas pela dissolução total do osso, sendo estas utilizadas para quantificar por Espectrometria de Absorção Atômica no modo chama ou com Forno e Grafite. Mandíbulas foram análisadas em Microscopia Eletrônica de Varredura e utilizando os acessórios Eletron Dispersive Spectroscopy para os elementos mais abundantes e Wavelenght dispersive Spectroscopy para investigar por análise semiquantitativa os mais abundantes elementos inorgânicos no osso destes animais, como forma de verificar se há variações nestes microelementos nos animais expostos a chumbo em comparação com controles. Como o chumbo se concentra na superfície do esmalte, também analisou-se o esmalte de primeiros molares inferiores, a fim de verificar se era visto o sinal do elemento chumbo nestes dentes. Foram usados ratos Wistar machos de 28 e 60 dias divididos em 2 grupos: C 28D (n=5) e Pb 28D (n=5) e, C 60D (n=12) e Pb 60D (n=17). Em todas as medidas de chumbo dos grupos controle as concentrações obtidas foram próximas ao limite de detecção, e houve sempre diferença estatisticamente significante (P<0.0001) quando os controles foram comparados aos grupos expostos a chumbo. As concentrações de chumbo obtidas no sangue de animais do grupo Pb 28D foi de 8,0 ug/dl (± 1.1) e no grupo Pb 60D foi de 7,2 ug/dl (± 0.89). Houve diferença estatisticamente significante entre as massas das tíbias (aferidas em balança e também a partir da quantidade de cálcio dissolvida em solução) do grupo C 60D (0,86 g ± 0,13) e Pb 60D (0,61 g ±0,11)(p=0.0004). As concentrações de chumbo detectadas nos ossos do grupo Pb 28D foi 8,02 (± 1,12) e no grupo Pb 60D foi de 43,3ug/g (± 13,26). Concentração de zinco no osso do grupo C 60D foi 0,22 mg/g e no grupo Pb 60D foi 0,22 mg/g (p>0.05). A concentração de magnésio no osso do grupo C 60D foi de 4,89 mg/g ± 0,74 e no grupo Pb 60D foi de 4,98mg/g ±0,79 (p>0.05). Os microelementos mais abundantes detectados nas tíbias contralaterais por Microscopia Eletrônica de varredura por EDS/WDS foram cálcio, fósforo, carbono, oxigênio, magnésio, sódio e potássio, não tendo sido detectadas variações nestes elementos entre os grupos controle e expostos a chumbo de 60 dias. O chumbo foi detectado apenas na região cervical dos dentes molares por MEV-EDS, e, nesta posição, apenas na forma de óxido de chumbo (deposição extrínseca) que pode ser útil para fins forenses ou de determinação de contaminação desconhecida. As conclusões deste estudo são: Houve diferença estatisticamente significante entre as massas de osso do grupo Pb 60D e C 60D. Mesmo não havendo diferença entre as concentrações de chumbo no sangue total de animais de 28 e 60 dias, houve quantidade de chumbo 5 vezes maior nos animais Pb 60D. Não houve diferenças nas concentrações de zinco e magnésio entre controles e animais expostos a chumbo. Os microelementos mais abundantes detectados nas tibias contralaterais por Microscopia Eletrônica de varredura por EDS/WDS foram cálcio, fósforo, carbono, oxigênio, magnésio, sódio e potássio, não tendo sido detectadas variações semi-quantitativas nestes elementos. O chumbo não foi detectado nem nos grupos controle ou expostos por MEV, e nos molares só foi detectada no grupo exposto como uma deposição extrínseca. / Lead is a highly toxic metal that is ubiquitous do to its great usefulness. Exposure to even low levels of lead (which do not cause symptoms of acute poisoning) is associated with cognitive and neurological disorders. Bone is considered the best marker of exposure to lead. Several chemical elements are found in bone, and some of them may have a different concentration or distribution due to exposure to lead. We tested the hypothesis that there are variations in the elements zinc and magnesium in the tibia of animals exposed to lead (being those elements determined by a conventional analytic chemistry technique). It was also tested whether variations in microelements could be detected by semiquantitative microanalysis in tibias of controls and animals exposed to lead. The objective of this project was to determine the concentration of lead in bone (tibia) of animals exposed to lead from pregnancy to day 28 and day 60. Besides lead, zinc and magnesium were also determined. Lead was also determined in whole blood collected at the end of the 2 time points. Quantitative measurements of lead, calcium, zinc and magnesium have been made in solutions obtained by dissolution of the bone by Atomic Absorption Spectrometry using flame or Graphite Furnace. Tibias were analyzed by scanning electron microscopy using the accessories Electron Dispersive Spectroscopy and Wavelength dispersive Spectroscopy for semiquantitative analysis of inorganic elements in the bone and molars of these animals. Lower molars were also analyzed by these means. Male Wistar rats aged 28 and 60 days were used in these study. In both these ages there were animals in the control (C 28D, n = 5 and C 60D, n=12) and lead exposed group (Pb 28D, n = 5 and Pb 60D, n = 17). Lead concentrations found in control groups were close to the detection limit, and there was always statistically significant differences (P <0.0001) when control groups were compared with those exposed to lead. Blood lead of groups Pb 28D and Pb 60D was 8.0 ug/dl (± 1.1) and 7.2 ug/dl (± 0.89), respectively. There was a statistically significant difference between the masses of the tibia (measured in balance and also from the amount of calcium dissolved in solution): C 60D showing 0.86 g (± 0.13 g) and 0.61 g (± 0, 11) of the Pb 60D group (p = 0.0004). Lead concentrations increased five times when the Pb 28D group was compared with the Pb 60D (8.02 and 43.3 ug/g)(p<0.0001). Zinc concentrations were not different in the C 60D (0.22 mg/g) and in the Pb 60D group (0.22 mg/g)(p>0.05). Magnesium concentrations were 4.89 mg/g in the C 60D and 4.98 mg/g in the Pb 60D (p>0.05). The most abundant trace elements detected in the contralateral tibiae by SEM-EDS/WDS were calcium, phosphorus, carbon, oxygen, magnesium, sodium and potassium and no variations in these elements were detected between the control and lead exposed groups. Lead was detected only in the cervical region of molar teeth of the lead exposed groups by SEM-EDS. This finding revealed lead in the lead oxide (extrinsic deposition) which may be useful for forensic purposes or for determining unknown contaminations. Conclusions: There was a statistically significant difference between the bone masses of the Pb 60D and C 60D groups. While there is no difference between lead concentrations in whole blood of animals 28 and 60 days, the amount of lead was 5 times higher in animals Pb 60D. There were no differences in the concentrations of zinc and magnesium between controls and lead exposed animals. The most abundant trace elements detected in the contralateral tibiae by SEM-EDS/WDS were calcium, phosphorus, carbon, oxygen, magnesium, sodium and potassium, and no semi-quantitative variations in these elements were detected in relation to exposure to lead. Lead was not detected either in control or exposed groups by SEM, and in molars it was only detected in the exposed group as an extrinsic deposition.

OBJETIVO: Evaluar el efecto de Coca-Cola® y Schweppes® Limón en la fuerza adhesiva, el adhesivo remanente y la microfiltración debajo de los brackets. Examinar mediante microscopio electrónico de barrido (MEB) el efecto de estas bebidas en el esmalte intacto y esmalte sellado. MÉTODO: Se cementaron 120 brackets en incisivos bovinos y se dividieron 1) grupo control, 2) Coca-Cola®, 3) Schweppes® Limón. Los dientes fueron sumergidos en las bebidas tres veces al día (15 minutos) durante 15 días. La fuerza de adhesión fue medida con una máquina universal de ensayos y el adhesivo remanente, utilizando un equipo de análisis de imagen. La microfiltración en la interfase esmalte-adhesivo y adhesivo-bracket se determinó utilizando azul de metileno. Para las observaciones al MEB se utilizaron 108 dientes. RESULTADOS: No se encontraron diferencias significativas en la fuerza adhesiva y el adhesivo remanente entre grupos. La microfiltración en la interfase esmalte-adhesivo para Coca-Cola® y Schweppes® Limón fue significativamente mayor que para el grupo control. En la interfase adhesivo-bracket la microfiltración de Coca-Cola® fue mayor que el grupo control, mientras que la microfiltración de Schweppes® Limón no difirió significativamente ni de Coca-Cola® ni del grupo control. Las bebidas produjeron erosión del esmalte y pérdida del material adhesivo. / Objective: To evaluate the effect of Coca-Cola® and Schweppes®-Limón on bond strength, adhesive remnant and microleakage beneath brackets. To examine by Scanning Electron Microscope (SEM) the effect of these drinks on intact and sealed enamel. Methods: 120 brackets were bonded to bovine incisors and divided into: 1)Control-group; 2)Coca-Cola®; 3)Schweppes®-Limón. The teeth were submerged in the drinks 3 times/day (15 minutes) during fifteen days. Shear bond strength was measured with a universal test machine, and adhesive remnant using image analysis equipment. Microleakage at the enamel-adhesive and adhesive-bracket interfaces was detected using methylene blue. 108 teeth were used to examine by SEM the effect of the drinks on intact and sealed enamel. Results: No significant differences were found in bond strength and adhesive remnant between groups. Microleakage at the enamel-adhesive interface for Coca-Cola® and Schweppes®-Limón was significantly greater than for the control. At the adhesive-bracket interface microleakage was significantly greater with Coca-Cola® than with the control whilst microleakage with Schweppes®-Limón did not differ significantly from either Coca-Cola® or the control. The drinks produced enamel erosion and loss of adhesive.

Heavy oil production depends on the understanding of mechanical and flow properties of unconsolidated or weakly consolidated sands under different loading paths and boundary conditions. Reconstituted bitumen-free Athabasca oil-sands samples were used to investigate the geomechanics of a steam injection process such as the Steam Assisted Gravity Drainage (SAGD). Four stress paths have been studied in this work: triaxial compression, radial extension, pore pressure increase and isotropic compression. Absolute permeability, end-point relative permeability to oil & water (kro and krw), initial water saturation and residual oil saturation were measured while the samples deformed. Triaxial compression is a stress path of increasing mean stress while radial extension and pore pressure increase lead to decreasing mean stress. Pore pressure increase experiments were carried out for three initial states: equal axial and confining stresses, axial stress greater than confining stress and confining stress greater than axial stress. Pore pressure was increased under four boundary conditions: 1) constant axial and confining stress; 2) constant axial stress and zero radial strain; 3) zero axial strain and constant confining stress; and 4) zero axial and radial strain. These experiments were designed to mimic geologic conditions where vertical stress was either S1 or S3, the lateral boundary conditions were either zero strain or constant stress, and the vertical boundary conditions were either zero strain or constant stress. Triaxial compression caused a decrease in permeability as the sample compacted, followed by appreciable permeability enhancement during sample dilation. Radial extension led to sample dilation, shear failure and permeability increase from the beginning. The krw and kro increased by 40% and 15% post-compaction respectively for the samples corresponding to lower depths during triaxial compression. For these samples, residual oil saturation decreased by as much as 40%. For radial extension, the permeability enhancement decreased with depth and ranged from 20% to 50% while the residual oil saturation decreased by up to 55%. For both stress paths, more shear-enhanced permeability was observed for samples tested at lower pressures, implying that permeability enhancement is higher for shallower sands. The pore pressure increase experiments showed an increase of only 0-10% in absolute permeability except when the effective stress became close to zero. This could possibly have occurred due to steady state flow not being reached during absolute permeability measurement. The krw curves generally increased as the pore pressure was increased from 0 psi. The increase ranged from 5% to 44% for the different boundary conditions and differential stresses. The kro curves also showed an increasing trend for most of the cases. The residual oil saturation decreased by 40-60% for samples corresponding to shallow depths while it increased by 0-10% for samples corresponding to greater depths. The reservoirs with high differential stress are more conducive to favorable changes in permeability and residual oil saturation. These results suggested that a decreasing mean stress path is more beneficial for production increase than an increasing mean stress path. The unconsolidated sands are over-consolidated because of previous ice loading which makes the sand matrix stiffer. In this work, it was found that over-consolidation, as expected, decreased the porosity and permeability (40-50%) and increased the Young’s and bulk moduli of the sand. The result is sand which failed at higher than expected stress during triaxial compression. Overall, results show that lab experiments support increased permeability due to steam injection operations in heavy oil, and more importantly, the observed reduction in residual oil saturation implies SAGD induced deformation should improve recovery factors. / text

The Sámi’s past activities have been documented historically from a European perspective, and more recently from an anthropological viewpoint, giving a generalised observation of the Sámi, during the study period of AD200-AD1800, as semi-nomadic hunter gatherers, with several theories suggesting that interaction with Europeans, through trade, led to the adoption of European activities by certain groups of the Sámi (Eiermann, 1923; Paine, 1957; Manker and Vorren, 1962; Bratrein, 1981; Mathiesen et al, 1981; Meriot, 1984). However, there is almost no information on the impact the Sámi had on the landscape, either before or after any adoption of European activities, and none investigating what cultural footprint or indicators would remain from Sámi or European occupation and/or activity within the typically podzolic soils of Northern Sweden. Consequently the thesis aims to contribute to the gap in knowledge through the formation of a podzol model identifying the links between anthropogenic activity and the alteration of podzol soils, and through the creation of soils based models which identify the cultural indicators associated with both Sámi and European activity; formed from the identification of cultural indicators retained within known Sámi and European sites. The methods used to obtain the information needed to achieve this were the pH and magnetic susceptibility from bulk soil samples and micromorphological and chemical analysis of thin section slides through the use of standard microscopy and X-ray fluorescence from a scanning electron microscope. The analysis revealed that the Sámi had an extremely low impact on the landscape, leaving hard to detect cultural indicators related to reindeer herding in the form of reindeer faecal material with corresponding phosphorous peaks in the thin section slides. The European footprint however, was markedly different and very visible even within the acidic soil environment. The European indicators were cultivation based and included phosphorous and aluminium peaks as well as a deepened, highly homogenised plaggen style anthropogenic topsoil rich in ‘added’ materials. An abandoned European site which visibly and chemically shows the formation of a secondary albic horizon within the anthropogenic topsoil also provides an insight into the delicate balance of cultivated soil in northern Sweden, whilst reinforcing the outputs identified in the podzol model. Due to the almost invisible Sámi footprint on the landscape, areas of overlap were impossible to identify however, there was no evidence of the adoption of European cultivation activities at any of the Sámi sites investigated. The only known area of interaction between the two cultures was an official market place which had been a Sámi winter settlement prior to its use as a market site. This site showed none of the reindeer based Sámi indicators or the cultivation based European indicators, but did contain pottery fragments which could be linked to trade or occupation. Overall, the thesis reinforces the low impact expected of the semi-nomadic Sámi and sheds light on the underlying podzolic processes influencing the anthropogenically modified soils of Northern Sweden. The podzol model is reinforced by several findings throughout the thesis and the soils based cultural indicator models for both Sámi and European activity have been successfully tested against independent entomological and palynological data and therefore provide reliable reference material for future studies.

The objective of my work was to develop HDPE clay nanocomposites for packaging with superior barrier (gas and water) properties by economical processing technique. This work also represents a comparative study of thermoplastic nanocomposites for packaging based on linear low density polyethylene (LLDPE), high density polyethylene (HDPE) and Nylon12. In this study properties and processing of a series of linear low density polyethylene (LLDPE), high density polyethylene (HDPE) and Nylon 12 nanocomposites based on Na-MMT clay and two different aspect ratio grades of kaolinite clay are discussed.

O chumbo é um metal muito tóxico e que tem ampla distribuição pela sua grande utilidade. Mesmo a exposição a baixos níveis (que não causam sintomas de intoxicação aguda) de chumbo é associada a desordens cognitivas e neurológicas. O osso é considerado o melhor marcador de exposição a chumbo. No tecido ósseo, vários elementos estão presentes, e alguns deles poderiam ter sua concentração modificada pela exposição a chumbo. Testou-se a hipótese de que haja variações nos elementos Zn e Mg nas tíbias de animais expostos a chumbo (por técnica de química analítica convencional). Testou-se também se variações em microelementos poderiam ser detectadas por técnicas semiquantitativas nas tíbias de controles e animais expostos a chumbo. O objetivo deste projeto foi caracterizar em animais expostos ao chumbo desde a gestação e controles as concentrações deste elemento no osso (tíbia) de animais de 28 e 60 dias. Além do chumbo, investigamos também a concentração de 2 outros microelementos no osso: zinco e magnésio. As medidas quantitativas de chumbo foram feitas no sangue total coletado ao final dos períodos. As medidas quantitativas de chumbo, cálcio, zinco e magnésio foram realizadas a partir de soluções ácidas obtidas pela dissolução total do osso, sendo estas utilizadas para quantificar por Espectrometria de Absorção Atômica no modo chama ou com Forno e Grafite. Mandíbulas foram análisadas em Microscopia Eletrônica de Varredura e utilizando os acessórios Eletron Dispersive Spectroscopy para os elementos mais abundantes e Wavelenght dispersive Spectroscopy para investigar por análise semiquantitativa os mais abundantes elementos inorgânicos no osso destes animais, como forma de verificar se há variações nestes microelementos nos animais expostos a chumbo em comparação com controles. Como o chumbo se concentra na superfície do esmalte, também analisou-se o esmalte de primeiros molares inferiores, a fim de verificar se era visto o sinal do elemento chumbo nestes dentes. Foram usados ratos Wistar machos de 28 e 60 dias divididos em 2 grupos: C 28D (n=5) e Pb 28D (n=5) e, C 60D (n=12) e Pb 60D (n=17). Em todas as medidas de chumbo dos grupos controle as concentrações obtidas foram próximas ao limite de detecção, e houve sempre diferença estatisticamente significante (P<0.0001) quando os controles foram comparados aos grupos expostos a chumbo. As concentrações de chumbo obtidas no sangue de animais do grupo Pb 28D foi de 8,0 ug/dl (± 1.1) e no grupo Pb 60D foi de 7,2 ug/dl (± 0.89). Houve diferença estatisticamente significante entre as massas das tíbias (aferidas em balança e também a partir da quantidade de cálcio dissolvida em solução) do grupo C 60D (0,86 g ± 0,13) e Pb 60D (0,61 g ±0,11)(p=0.0004). As concentrações de chumbo detectadas nos ossos do grupo Pb 28D foi 8,02 (± 1,12) e no grupo Pb 60D foi de 43,3ug/g (± 13,26). Concentração de zinco no osso do grupo C 60D foi 0,22 mg/g e no grupo Pb 60D foi 0,22 mg/g (p>0.05). A concentração de magnésio no osso do grupo C 60D foi de 4,89 mg/g ± 0,74 e no grupo Pb 60D foi de 4,98mg/g ±0,79 (p>0.05). Os microelementos mais abundantes detectados nas tíbias contralaterais por Microscopia Eletrônica de varredura por EDS/WDS foram cálcio, fósforo, carbono, oxigênio, magnésio, sódio e potássio, não tendo sido detectadas variações nestes elementos entre os grupos controle e expostos a chumbo de 60 dias. O chumbo foi detectado apenas na região cervical dos dentes molares por MEV-EDS, e, nesta posição, apenas na forma de óxido de chumbo (deposição extrínseca) que pode ser útil para fins forenses ou de determinação de contaminação desconhecida. As conclusões deste estudo são: Houve diferença estatisticamente significante entre as massas de osso do grupo Pb 60D e C 60D. Mesmo não havendo diferença entre as concentrações de chumbo no sangue total de animais de 28 e 60 dias, houve quantidade de chumbo 5 vezes maior nos animais Pb 60D. Não houve diferenças nas concentrações de zinco e magnésio entre controles e animais expostos a chumbo. Os microelementos mais abundantes detectados nas tibias contralaterais por Microscopia Eletrônica de varredura por EDS/WDS foram cálcio, fósforo, carbono, oxigênio, magnésio, sódio e potássio, não tendo sido detectadas variações semi-quantitativas nestes elementos. O chumbo não foi detectado nem nos grupos controle ou expostos por MEV, e nos molares só foi detectada no grupo exposto como uma deposição extrínseca. / Lead is a highly toxic metal that is ubiquitous do to its great usefulness. Exposure to even low levels of lead (which do not cause symptoms of acute poisoning) is associated with cognitive and neurological disorders. Bone is considered the best marker of exposure to lead. Several chemical elements are found in bone, and some of them may have a different concentration or distribution due to exposure to lead. We tested the hypothesis that there are variations in the elements zinc and magnesium in the tibia of animals exposed to lead (being those elements determined by a conventional analytic chemistry technique). It was also tested whether variations in microelements could be detected by semiquantitative microanalysis in tibias of controls and animals exposed to lead. The objective of this project was to determine the concentration of lead in bone (tibia) of animals exposed to lead from pregnancy to day 28 and day 60. Besides lead, zinc and magnesium were also determined. Lead was also determined in whole blood collected at the end of the 2 time points. Quantitative measurements of lead, calcium, zinc and magnesium have been made in solutions obtained by dissolution of the bone by Atomic Absorption Spectrometry using flame or Graphite Furnace. Tibias were analyzed by scanning electron microscopy using the accessories Electron Dispersive Spectroscopy and Wavelength dispersive Spectroscopy for semiquantitative analysis of inorganic elements in the bone and molars of these animals. Lower molars were also analyzed by these means. Male Wistar rats aged 28 and 60 days were used in these study. In both these ages there were animals in the control (C 28D, n = 5 and C 60D, n=12) and lead exposed group (Pb 28D, n = 5 and Pb 60D, n = 17). Lead concentrations found in control groups were close to the detection limit, and there was always statistically significant differences (P <0.0001) when control groups were compared with those exposed to lead. Blood lead of groups Pb 28D and Pb 60D was 8.0 ug/dl (± 1.1) and 7.2 ug/dl (± 0.89), respectively. There was a statistically significant difference between the masses of the tibia (measured in balance and also from the amount of calcium dissolved in solution): C 60D showing 0.86 g (± 0.13 g) and 0.61 g (± 0, 11) of the Pb 60D group (p = 0.0004). Lead concentrations increased five times when the Pb 28D group was compared with the Pb 60D (8.02 and 43.3 ug/g)(p<0.0001). Zinc concentrations were not different in the C 60D (0.22 mg/g) and in the Pb 60D group (0.22 mg/g)(p>0.05). Magnesium concentrations were 4.89 mg/g in the C 60D and 4.98 mg/g in the Pb 60D (p>0.05). The most abundant trace elements detected in the contralateral tibiae by SEM-EDS/WDS were calcium, phosphorus, carbon, oxygen, magnesium, sodium and potassium and no variations in these elements were detected between the control and lead exposed groups. Lead was detected only in the cervical region of molar teeth of the lead exposed groups by SEM-EDS. This finding revealed lead in the lead oxide (extrinsic deposition) which may be useful for forensic purposes or for determining unknown contaminations. Conclusions: There was a statistically significant difference between the bone masses of the Pb 60D and C 60D groups. While there is no difference between lead concentrations in whole blood of animals 28 and 60 days, the amount of lead was 5 times higher in animals Pb 60D. There were no differences in the concentrations of zinc and magnesium between controls and lead exposed animals. The most abundant trace elements detected in the contralateral tibiae by SEM-EDS/WDS were calcium, phosphorus, carbon, oxygen, magnesium, sodium and potassium, and no semi-quantitative variations in these elements were detected in relation to exposure to lead. Lead was not detected either in control or exposed groups by SEM, and in molars it was only detected in the exposed group as an extrinsic deposition.

This work were requested by Uddeholms AB. Uddeholm is the worldś leading manufacturer of high performance tool steel for industrial tools. The company exists worldwide and is present in over 100 countries. One of the company’s main production processes is manufacturing powder steels with extremely high quality. In this work, one of these steels has been analyzed to evaluate the presence and distribution of non-metallic inclusions. Higher demands on quality and more global competition worldwide means that you always have to strive towards perfection in the manufacturing processes. Non-metallic inclusions have severe effects on the mechanical properties of steels. That's why it's of utmost importance to investigate their presence in the tool steel and especially their size. The reason for this is because it's the largest inclusions that's the most dangerous for the material. To obtain a statistically number of certainty of the largest of inclusions, very vast areas of steel have to be examined. Therefore a theoretical method of extrapolation is often used instead to approximate the distribution of the largest inclusions. The precision of this method is still very uncertain. Different methods of this kind of analysis do exist. The method applied in this work of degree is extreme values analysis by statistics of extreme values (SEV). To ensure the pre-conditions of the extreme values analysis, a large quantity of powder steel was analyzed. This was done by light-optic microscopy (LOM) and exclusively performed by Uddeholms AB at their R&amp;D-facility (Research and development-facility) in Hagfors. At Karlstad Universityś test-facility specimens were subjected to ultrasonic fatigue testing at 20 kHz. The specimens derived from the same material as the ones examined in LOM. The result from the ultrasonic fatigue testing were that the largest inclusions in the material were found. This was done by applying very high cycle fatigue (VHCF). To calculate the maximum theoretical inclusion size, SEV was used. The extreme values analysis was performed on gathered data from both LOM and VHCF. All fracture surfaces from the ultrasonic fatigue testing were then examined in scanning electron microscope (SEM) at Karlstad University. In SEM, the largest inclusion in every fractured surface was identified and measured. The maximum real inclusion size from the fractured surfaces was then compared to the maximum theoretically calculated inclusion size from the extreme values analysis. As it turned out the real inclusion size proved to be slightly larger than the theoretical. The difference between them was found to be 3,25 µm. Conclusions drawn were that Uddeholms powder steel exhibits very high purity and that extreme values analysis as an analytical method is recommended. However, the analysis should be repeated to underline the chosen solution methodology.

This thesis is focused on electron microscopy which issue is discussed at the beginning of work. The main attention is dedicated to the Environmental electron microscope, especially the differentially pumped chamber, which the thesis deals with. There is a production of an experimental chamber for analysis of shock waves on going therefore main goal of this thesis was to analyze the flow pattern in this chamber. Using the Ansys Fluent program, simulations of the characteristic flow that arises from the pumping of the vacuum chambers namely the ultrasonic flow at low pressures on which the most suitable turbulent module was applied as well as the degree of discretization was performed. The final analysis of this flow pattern is primarily focused on the localization of the shock wave which experimental evidence is to be lodged by shadow optical method as a part of the new concept of the chamber. The basis for the simulation of the chamber was taken over by Dr. Danilatos, with which the results were compared.