University, Diss., 2000--Freiburg (Breisgau). / Parallelt.: Measurement of single w production and triple gauge boson couplings in e+e- collisions at s=161-189 GeV. Text. engl.

University, Diss., 2000--Freiburg (Breisgau). / Text engl.

Univ, Diss., 2002--Heidelberg.

University, Diss., 2004--Bonn.

In this work, we present a new method for seismic waveform characterization, which is aimed at extracting detailed litho-stratigraphical information from seismic data. We attempt to estimate the lithological attributes from seismic data according to our parametric representation of stratigraphical horizons, where the parameter values provide us with a direct link to nature of lithological transitions. We test our method on a seismic dataset with a strong diagenetic transition (opal-A to opal-CT transition). Given some information from cutting samples of well, we use a percolation-based model to construct the elastic profile of lithological transitions. Our goal is to match parametric representation for the diagenetic transition in both real data and synthetic data given by these elastic profiles. This match may be interpreted as a well-seismic tie, which reveals lithological information about stratigraphical horizons. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

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My diploma thesis designs a suitable alternace of shifting a production for Havlík Opal Ltd. company. This step should fulfil the firms requierements to lower the costs, savings creation, modersination of technology, production atuomation and help to generate higher profit.

15 samples of gem opals were analyzed by laser ablation inductively coupled plasma mass spectrometry (LA ICP-MS) and inductively coupled plasma mass spectrometry (ICP-MS). For this study were selected the most representative samples from Slovakia, Australia, Peru, Ethiopia, Mexico, USA and the Czech Republic. These samples were obtained from private collections. The study focuses on the geochemical relationships between various forms of opal originating from igneous and sedimentary environments based on the results from LA ICP-MS and ICP-MS. The major and trace element compositions are unique for each studied opal locality and important for understanding numerous aspects of opal formation. Major element analysis shows that opals are essentially pure SiO2 (77 - 92 wt. %). Al, Fe, Ca, K, Na and Mg are the main elemental impurities. The concentrations of the trace elements vary strongly depending on the opal locality. Differences were found, e.g., in the concentrations of REE and some refractory elements, which might be indicative for determining the provenance of opals. Many studies have been published explaining the origin of luminescence, microstructures and the thermal properties of opals. However, there are very few comprehensive studies comparing gem opals from the most important historical and...

The void spaces in colloidal crystals (opals, three-dimensional (3D) close-packed arrays of silica nanospheres) and their replicas are used as templates in the fabrication of new nanostructured materials. 3D ordered nanomeshes and nanosphere arrays are readily obtained by chemical and/or electrochemical methods. Using silica opal templates, metals or polymers are infiltrated into the interstices between the silica nanospheres. Subsequent dissolution of the opals with HF solution produces open 3D mesh structures. Metal (such as Ni, Co, Fe, Pd, Au, Ag, and Cu) and conductive polymer (such as polyaniline) meshes are obtained by electrochemical deposition approach, while the nonconductive polymer (such as poly(methyl methacrylate) (PMMA)) meshes are synthesized by chemical polymerization method. Some new types of meshes are fabricated by the conversion of metal meshes and polymer meshes. NiO meshes are formed by oxidizing Ni meshes in the air. The NiO meshes exhibit higher volume occupation fraction than Ni meshes and the nanocrystalline sizes of NiO particles can be adjusted by the oxidation temperature. Due to the mechanical flexibility of polymer meshes, the compression of PMMA meshes produces deformed PMMA meshes which contain oblate pores. These meshes can be again served as templates to prepare new types of colloidal crystals (nanosphere arrays) and specific nanocomposites. By the use of poorly conductive NiO mesh or PMMA mesh arrays as templates, 3D periodic metal nanosphere arrays, such as those of Ni, Co, Au and Pd, are readily fabricated by the electrodeposition method. Metal/NiO or Metal/PMMA composites can also be obtained if the templates are left intact. The magnetic behavior of metal (such as Ni and Co) meshes and sphere arrays has been investigated. These nanoscale arrays show significantly enhanced coercivities compared with bulk metals, due to the size effect of the nanometer dimensions of the components in meshes and sphere arrays. Angle-dependent magnetic properties of Ni and Co sphere array membranes exhibit out-of-plane anisotropy.

No estado do Rio Grande do Sul, os garimpos de pedras preciosas estão distribuídos em duas regiões principais: no Distrito Mineiro de Ametista do Sul (maior produtor de ametista) e no Distrito Mineiro de Salto do Jacuí (maior produtor de ágata). Nestes dois distritos mineiros são explorados geodos, parcial ou totalmente preenchidos por camadas intercaladas de ágata, quartzo incolor, ametista, calcita e opala. O processo de extração desses geodos gera grande quantidade de rejeito, composto tanto pela rocha portadora do minério como também por minério de baixa qualidade. No município de Soledade se concentram as principais empresas de beneficiamento e também o comércio dos materiais gemológicos explorados no Rio Grande do Sul. No entanto, a maioria dos objetos produzidos que visam à exportação se repete nas diversas indústrias beneficiadoras sem diferencial aparente. A opala encontrada nos garimpos de Salto do Jacuí ocorre em muitas cores. A opala branca é a mais comum e não é valorizada, gerando, assim, significativa quantidade de rejeito. Através deste estudo, objetiva-se estabelecer uma metodologia de beneficiamento por usinagem CNC do rejeito de opala branca e ágata oriundo do Distrito Mineiro de Salto do Jacuí, que agregue valor pelo design e tecnologia. Considerando que os processos mais utilizados nas indústrias atualmente para a ágata, o tingimento e o corte em chapas, não se aplicam à opala, pode-se afirmar que a introdução da tecnologia de usinagem CNC neste setor pode auxiliar no aproveitamento desse material, ao modificá-los e valorizá-los como objetos de adorno sob a forma de camafeus. A metodologia empregada para a presente pesquisa consistiu de etapas de identificação dos locais de extração de ágata e de opala branca do Estado; avaliação dos procedimentos mais utilizados para beneficiamento destes materiais; estudo e análise do material por técnicas específicas; ensaios de usinagem CNC, análise das fresas utilizadas e dos materiais envolvidos após os processos de usinagem e desenvolvimento de produto. Foram realizados nove ensaios de usinagem e as análises posteriores, identificando nos resultados obtidos que, com as fresas adequadas destinadas ao desgaste (maior diâmetro) ou acabamento (menor diâmetro de ponta), quando utilizados em conjunto com parâmetros e estratégias de usinagem bem definidos, são suficientes para que se alcance o objetivo definido nesta pesquisa. / In the state of Rio Grande do Sul, the precious stones mines are distributed in two main regions: in the Mining District of South Amethyst (largest producer of amethyst) and the Mining District of the Salto Jacuí (largest producer of agate). In these two districts Geodis miners are exploited, partially or completely filled by intercalated layers of agate, clear quartz, amethyst, opal and calcite. The extraction process of Geodis generates large amounts of waste, comprising both the rock of the ore carrier as well as of low quality ore. In the municipality of Soledade focus the main company to benefit from trade and gemological materials used in Rio Grande do Sul. However, most of the objects produced aimed at the export is repeated in various industries benefit without apparent difference. The opal found in the mines of the Salto Jacuí appears in many colors. The white opal is the most common and is not valued, thus generating significant amount of waste. Through this study, that aims to establish a methodology for processing by the CNC machining waste of opal and white agate from the Mining District of the Salto Jacuí, a great value was added for design and technology. Whereas the most currently used in industries for agate, dyeing and cut into plates, are not applied to the opal, one can say that the introduction of CNC machining in this sector can assist in the exploitation of such material, to modify and value them as objects of adornment in the form of camafeus. The methodology used for this research consisted of steps of identifying locations for extraction of opal and white agate the state, evaluate the procedures used for further processing of these materials, study and analysis of the material by specific techniques, testing of CNC machining, analysis of cutters and materials used after the processes involved in machining and product development. Were conducted nine tests of machining and the subsequent analysis, identifying the results that, with the cutters suitable for the wear (larger diameter) or finishing (minor diameter of tip), when used together with parameters and machining strategies for well-defined, are sufficient to achieve the goal defined in this study.