The aims of the studies underlying this thesis were to assess the exposure to quartz in Swedish iron foundries and to determine the cancer morbidity for Swedish foundry workers. A cohort of 3,045 foundry workers and a final measurement database of 2,333 number of samples was established. The exposure measurements showed high levels of respirable quartz, in particular for fettlers and furnace and ladle repair workers with individual 8 hr TWA (GM=0.041 and 0.052 mg/m3; range 0.004-2.1 and 0.0098-0.83 mg/m3). In our database, the quartz concentrations as 8hr TWAs of current and historical data varied between 0.0018 and 4.9 mg/m3, averaging 0.083 mg/m3, with the highest exposures for fettlers (0.087 mg/m3) and furnace and ladle repair workers (0.42 mg/m3). The exposure for workers using respirators assuming full effect when used were assessed quantitatively, revealing workers with actual exposure exceeding the occupational exposure limits. Overall cancer morbidity was not increased, but the incidence of lung cancer was significantly elevated (SIR 1.61; 95 % CI 1.20-2.12). In the cohort study, significant associations between lung cancer and cumulative quartz exposure were detected for quartz doses of 1-2 mg/m3 * year (SIR 2.88; 95 % CI 1.44-5.16) and >2 mg/m3 * year (SIR 1.68; 95 % CI 1.07- 2.52). These findings were not confirmed in the case-control analysis. The agreement between the estimated exposure in our early historical model and the development model showed a regression coefficient of 2.42, implying an underestimation of the historical exposure when using the development model data. The corresponding comparison between the development and the validation model based on our survey data showed a B of 0.31, implying an overestimation of present exposures when using data from the validation model. The main conclusions of the thesis are that certain foundry workers are still exposed to high levels of quartz, and the overall excess lung cancer could not be confirmed in the exposure-response analysis.

No description available.

No description available.

published_or_final_version / abstract / Chemistry / Doctoral / Doctor of Philosophy

Nanostructured, porous materials offer great promise for application in areas such as energy storage, photovoltaics, and catalysis. These materials are often difficult to characterize because they are structurally and compositionally inhomogeneous, and disordered with features to small to be resolved by scanning probe techniques such as atomic force microscopy (AFM) and scanning electron microscopy (SEM). These shortcomings require that new techniques be developed that can be applied to real world systems to elucidate how the interplay of material composition and structure alters their performance. Towards this end, the development of a hybrid quartz crystal microbalance/ ellipsometric porosimetry (QCM/EP) technique is being pursued to facilitate the determination of a number of material parameters such as porosity, pore size distribution, and surface area. Additionally, the use of adsorbate probe molecules of varying polarity gives further information about adsorbate-surface interactions and surface chemistry characteristics. Simultaneous acquisition of both mass-based and refractive index based adsorption isotherms fosters mechanistic understanding about the behavior of adsorbates confined in mesopores while at the same time reducing the uncertainty in the analysis of the optical parameters acquired via ellipsometry. To highlight the power of this approach, studies of TiO₂ and TiC, electrode materials as model systems will be presented that have helped us validate measurement and modeling protocols for extracting physical properties. / text

No description available.

This research evaluates four options to produce quality axle load data for pavement design: piezoelectric WIM sites (corrected and uncorrected data), static weigh scales, and a piezo-quartz WIM site. The evaluation applies four data quality principles: data validity, spatial coverage, temporal coverage, and data availability. While all principles are considered, the research contributes in the development and application of an integrated and sequential approach to assess data validity of the options by performing analyses to determine the precision and accuracy of axle load measurements. Within the context of Manitoba, the evaluation reveals that data produced by piezo-quartz and static weigh scales have superior validity, with piezo-quartz data offering better temporal coverage, data availability, and future geographic coverage. Ultimately, the selection of the best option for providing quality axle load data depends on the relative importance of data quality principles for producing data supporting sound pavement designs and infrastructure management decisions. / May 2017

Quartzite samples taken in the east part of Krkonoše-Jizera Massif belong to metasedimentary cover of paraautochtonous unit. Rocks underwent a polyphase deformation which established a strong shape preffered orientation (SPO) of quartz grains. In folded quartz veins, deformation overprint mechanisms and microstructure, CPO and SPO relations were studied. For determination of crystal preffered orientations (CPO) the method of computer integrated polarization microscopy (CIP) was used. Microstructural analysis was focused on grain sizes, aspect ratios, long axis orientations and their relation to the deformation overprint grade. Results implies that dominant mechanism of quartz grain recrystallization is grain boundary migration. Folds were created by simple shear in microscale. The deformation overprint grade is strongest in the top of the fold hinge, where grains achieve highest aspect ratios and sizes. In the lower parts of the fold hinge the original CPO is preserved in small grains and SPO has similar orientation to original CPO. During folding CPO and SPO rotated with shear direction in dependance on deformation overprint grade.

Introduction It is well established that gold mine dust is a major cause of pneumoconiosis and other lung diseases. The main sources of dust in gold mines are well documented. Rock drill operators using pneumatic percussion rock drills are at the sharp end of exposure due to the very nature of the drilling process in that rock is pulverized and liberate large amounts of dust even with the addition of copious amounts of water. Historically it has been found that the gold bearing rock formations in South Africa typically contain about 30% quartz. (1) Keeping this in mind, the potential for overexposure is obvious. The actual exposure of rock drill operators to dust and quartz is not well documented and for this reason this research focuses on this particular occupation. Objectives To measure the respirable dust and quartz exposure of Rock Drill Operators in two typical gold mines in the Free State province of South Africa in 2007. Methods This study is a descriptive, cross sectional, rapid assessment based on the findings of gravimetric sampling results taken at Rock Drill Operators working underground on two different gold mines. The actual gravimetric sampling was done in accordance with NIOSH methodology. The study population consisted of 30 Rock Drillers on one mine and another 30 on a second mine. The Rock Drill Operators was randomly selected using their company numbers and selected by the “Excel” program random number selection function. Ordinary gravimetric sampling, using Gillair pumps, was used and weighing done on the mine by a qualified and well experienced Air Quality Analyst using an appropriate methodology compatible with international best practices. Quartz analysis was done at the National Institute for Occupational Health (NIOH) in Johannesburg using a Phillips X-Ray diffraction. (Photo 2). The methodology used by the laboratory technician is conducted strictly according to the manufacturer’s specifications and in line with international best 5 practices. This laboratory participates in quality assurances programmes and is highly regarded internationally. Results The initial hypothesis that exposure underestimation in the past in terms of this particular occupation is confirmed and could be contributable to the difficulties typically experienced when using the traditional gravimetric sampling method. The average quartz percentage was determined to be 25.45% for mine 1 and 38.49% for mine 2 giving an average of 30.67% for both mines. The Total Mass means was 0.73 and 0.23 mg for mine 1 and 2 respectively with an average for the two mines being 0.49 mg. Results for Time Weighted Averages revealed values of 0.69 and 0.22 mg/m3 for mine 1 and 2 respectively with an average of 0.46 mg/m3 for both. In terms of Air Quality Index (AQI) the values were 1.4 and 0.6 for mine 1 and 2 respectively with an average for both mines therefore being 1.1. A comparison with the South African OEL for quartz showed overexposure on 32% of all rock drill operators sampled. When using the NIOSH OEL that figure is even worse at 72%. Based on these results it would thus be fair to conclude that Rock drill operators working without appropriate respiratory equipment will be overexposed and therefore potentially suffer ill health as a result. Discussion and conclusion Rock drill operators are potentially exposed to high levels of harmful dust and quartz in their normal daily work if not adequately protected using good, effective appropriate and comfortable respiratory protective equipment (RPE) and additionally having proper ventilating velocity. At an average Air Quality Index (AQI) of 1.1, it would require the mine Occupational Hygienist to immediately institute remedial action in conjunction with an investigation to determine the reasons for such overexposure. The AQI of 1.46 and 0.6 for Mine 1 and 2 respectively curiously beg the question as to why there is a difference. The answer unfortunately is not clear at first glance as both mines wetted the stope working faces equally well, ventilates the faces with similar velocities which in turn alludes to similar dilution factors but the only reasonable deduction that could be made is that high TWA respirable quartz pollutant concentrations (mg/m3) values in lots of cases corresponded with low actual quartz values. This could be co-incidental but in fact caused the TWA graph to be inversely proportional to the AQI graph. Couple this to the fact that the actual dust burden is lower in Mine 2 compared to Mine 1 as confirmed by the TWA values obtained, then the results becomes easier to interpret. However, the assumption is made that the TWA values should enjoy more preference in the analytical sense as it could be compared directly to OEL’s which serves to highlight the hypothesis very clear in that rock drill operators are over exposed to a high degree of certainty which in turn concurs with other research done in the past. The fact that the methods used to drill holes in order to be charged up with explosives has largely remained unchanged for more decades in the mining industry with no viable alternative on the horizon, emphasizes the fact that focused attention and proper risk assessment is called for to protect rock drill operator from harmful exposure. That said the normal paper dust mask cannot in all good conscience be regarded as appropriate RPE for this occupation. The aforementioned risk assessment must determine and ultimately classify which occupations would benefit from “upgrading” to better quality dust masks. To accept only one type of dust mask on a mine would be considered a travesty and contrary to the application of all good occupational hygiene principles. Failing to expedite the aforementioned risk assessment on RPE per occupation will result in failure to place effective safeguard measures in place to protect rock drill operators from harmful dust and will mean that their health will be compromised in time. The development of air line fed type hard hats incorporating a face shield, harness fitted with moisture trap, filter and a snap fit attachment to a compressed air line is likely to be the ultimate solution provided that it is light, comfortable and the introduction is done in a manner that will ensure the understanding in the benefits to be derived from using such a device in the place of ordinary dust masks by Rock 7 Drill Operators. Ultimately, using the Occupational Hygiene hierarchy of control that dictates the first consideration of such control being elimination, coupled with the horrendous ergonomic problems faced by rock drill operators, the solution seems to point inevitably towards meganisation. Using a person in the same homogeneous exposure group (HEG) as that of the rock drill operator as a forced alternative is not advisable as the exposure of a rock drill operator is very unique and certainly not comparable to that of a winch driver for example. The wet environment certainly warrants the investigation into alternative methods for sampling as normal, traditional methods proved to be inconsistent, unreliable and often unusable.

As ocorrências estudadas da Sequência da Serra da Boa Vista (SSBV) balizam a borda leste do Quadrilátero Ferrífero nos distritos Santa Rita Durão, Bento Rodrigues e Camargos, da cidade de Mariana até a norte de Catas Altas. Sua geologia e as mineralizações de ouro foram enfocados nessa pesquisa baseada em mapeamento 1:25.000, levantamentos estratigráficos detalhados, estudos mineralógico-petrográficos, litogeoquímicos multielementares e das mineralizações auríferas e de morfologia e microgeoquímica de grãos de ouro e minerais associados via MEV-EDS, visando-se a evolução precambriana e a metalogênese do ouro da SSBV, bem como suas relações com as demais rochas da área, principalmente dos supergrupos Minas e Espinhaço. A área compreende um embasamento arqueano granito-gnáissico TTG em contato milonítico com rochas supracrustais do Greenstone Belt Rio das Velhas (Supergrupo Rio das Velhas) e coberturas paleoproterozóicas dos supergrupos Minas e Espinhaço (anteriormente Série Itacolomi) e da SSBV, com coberturas cenozóicas de canga e alúvio-coluvionares. A SSBV é constituída por quartzitos micáceos com estratificações cruzadas acanaladas de pequeno porte a metaconglomerados, caracteristicamente com fuchsita e sulfetos detríticos, com grânulos a calhaus de metachert e, localmente, de itabiritos. Em menor quantidade e mais restritos ocorrem ainda metaconglomerados polimíticos com seixos de quartzitos, metacherts e itabiritos, magnetita-cloritóide quartzitos com estratificações cruzadas acanaladas de pequeno porte com intercalações de grafita e hematita filitos e turmalinitos, assim como metabrechas intraformacionais itabiríticas. Essas rochas apresentam facies xisto verde predominante, a anfibolito, na parte leste da área. A SSBV desenvolveu-se em uma bacia alongada, de direção geral norte-sul, compartimentada, diretamente sobre o embasamento arqueano, com contribuição quartzosa do complexo gnáissico migmatítico TTG e, possivelmente, dos Metagranitóides Borrachudos (arqueanos), e contribuição detrítica do ouro das rochas do Greenstone Belt Rio das Velhas. A compartimentação da bacia levou à sedimentação de facies distintas - ao menos, no início de sua evolução - reforçada por tectônica sinsedimentar ao longo da deposição; nas facies superiores da SSBV predominam amplamente quartzitos micáceos com lentes de metaconglomerados de grânulos de metachert. O ambiente deposicional remete a uma planície de rios entrelaçados, temporariamente alagada e retrabalhada em ambiente intramaré, com inundação marinha final. O estudo das minas Ouro Fino, Cata Preta e Tesoureiro e do garimpo Fazenda Gualaxo mostrou serem as mineralizações de ouro da SSBV singenéticas, de tipo paleoplacer, com remobilização por veios de quartzo internos ao pacote sedimentar (da SSBV), de origens diagenéticas a metamórficas - de tipo paleoplacer modificado. Os grãos de ouro da SSBV apresentam teores de prata variáveis de até 15%, sem paládio, reforçando a proveniência exclusiva do ouro do Greenstone Belt Rio das Velhas. Os resultados obtidos e as observações nas continuações setentrionais da SSBV, incluindo o garimpo do Morro da Água Quente e as minas históricas de Pitanguí, Quebra Osso até Brumado, apontam para um padrão metalogenético único de mineralizações auríferas singenéticas de tipo paleoplaceres e paleoplaceres modificados, descaracterizados em proporções variáveis por retrabalhamentos tectono-metamórficos policíclicos. O potencial aurífero regional da SSBV é confirmado como elevado e para a sua definição são recomendados estudos específicos prospectivos e de viabilidade econômica. / The Sequência da Serra da Boa Vista (SSBV) stratches in a narrow belt of quartzites and metaconglomerates along the eastern border of the Quadrilátero Ferrífero in the districts of Santa Rita Durão, Bento Rodrigues and Camargos from Mariana, Minas Gerais to north of Catas Altas. The geology and gold mineralizations of the SSBV were studied, based on 1:25.000 mapping, detailed stratigraphical cross sections, mineralogical and petrographical studies, lithogeochemistry, geochemistry of the gold mineralizations and morphology and microgeochemistry of gold grains and associated minerals via SEM-EDS in order to understand better the Precambrian evolution and the metallogenesis of the gold of the SSBV as their as its relationships to other rock units of the region, mainly the Minas and Espinhaço supergroups. The study area comprises an Archean basement of TTG granitic gneisses in mylonitic contact with supracrustal rocks of the Rio das Velhas Greenstone Belt (Rio das Velhas Supergroup) and Paleoproterozoic metasedimentary deposits of the Minas and Espinhaço supergroups (formerly, Itacolomi Series) and the SSBV, with Cenozoic canga and alluvial and colluvial covers. Regionally, greenschist facies metamorphism prevails, grading to amphibolite facies in the eastern part of the area. SSBV consists of micaceous quartzites with small-scale cross-bedding and metaconglomerates with granules and pebbles of metachert and, locally, itabirites, characteristically with fuchsite and detritic sulfides. In smaller amounts and more restricted there occur polymictic metaconglomerates (with quartzite, metachert and itabirite pebbles), magnetite-chloritoid quartzites (with small-scale cross-bedding and intercalations of graphite and hematite phyllites and tourmalinite layers), as well as intraformational itabiritic metabrecchias. SSBV deposits developed directly upon the Archean basement in a narrow, elongate basin oriented and subdivided longitudinally in a north-south direction that received quartzose sediments from the gneissic-migmatitic TTG Complex and possibly from the Archean Borrachudos Metagranitoid; detritic gold came from the Rio das Velhas Greenstone Belt. Initial basin subdivision and ensuing synsedimentary tectonics led to sedimentation of different facies. In the upper part of the SSBV micaceous quartzites with lenses of metachert-granule metaconglomerates predominate. The depositional environment in the basin was a coastal braided river plain with periodic marine incursion accompained by intratidal reworkings and, finally, shallow-marine inundation. The study of the Ouro Fino, Cata Preta and Tesoureiro mines and the Garimpo Fazenda Gualaxo showed the gold mineralizations of the SSBV to be syngenetic, of paleoplacer and modified paleoplacer types with diagenetic to metamorphic remobilization (quartz veins) within the sedimentary sequence. Gold grains of the SSBV show variable silver contents up to 15%, without palladium, demonstrating the exclusive provenance of the gold from the Rio das Velhas Greenstone Belt. Results and observations in the northern SSBV, including the Garimpo do Morro da Água Quente and the Pitanguí and Quebra Osso-Brumado historic mines, indicate a homogeneous metallogenetic pattern of syngenetic gold mineralizations of paleoplacer and modified paleoplacer types, obliterated in varying proportions by tectono-metamorphic polyciclic reworkings. This study confirms the high regional gold potential of the SSBV and recommends specific prospective studies and economic viability analyses for its more complete definition.