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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
241

Proposta de um índice de desempenho ambiental para a mineração a céu aberto

Silva, Felipe Vargas e January 2014 (has links)
Esta dissertação tem como objetivo criar uma ferramenta mais abrangente de avaliação do desempenho ambiental da mineração a céu aberto, para posteriormente avaliar o desempenho ambiental desta atividade econômica, uma vez que os critérios de avaliação de impactos na mineração atuais não consideram o impacto ambiental causado por atividades de lavra a céu aberto na paisagem. Para mensurar o impacto na paisagem causado pela mineração foram utilizados dados de sensoriamento remoto do sensor TM do satélite Landsat 5 e técnicas de geoprocessamento. Posteriormente, as cenas foram submetidas ao script de análise de fragmentação da paisagem V-LATE 2.0 beta para o ArcMAP™ 10.1. Após os impactos ambientais terem sido mensurados e agregados em um índice, torna-se possível uma quantificação do desempenho ambiental da atividade de mineração. Como aplicação do novo índice criado, foi feito um estudo comparativo entre a mina N5W e a cultura da soja no município de Sorriso, MT. Tal estudo permitiu concluir que a atividade da mineração a céu aberto, se realizada com as devidas medidas mitigatórias, apresenta desempenho ambiental comparável a outras atividades econômicas de mesmo porte produtivo. / This dissertation aims to create a more comprehensive tool for assessing environmental performance of open pit mines to assess the environmental performance, since the criteria for assessment of impacts on current mining do not consider the environmental impact of open-pit mining activities in the landscape. To measure the impact on the landscape caused by mining techniques were used remote sensing data from Landsat 5 TM sensor and geoprocessing techniques. Then the scenes were analyzed by V-LATE 2.0 beta script for ArcMAP™ 10.1 software. After the environmental impacts have been measured and aggregated into an index, it is possible to quantify the environmental performance of mining activities. As an application of the new index created, a comparative study between N5W mine and soybean in the municipality of Sorriso, MT was done. This study concluded that the open pit mining whether performed with appropriate mitigation measures, has environmental performance similar to other economic activities with the same production scale.
242

Proposta de metodologia para avaliação da qualidade das águas na área de influência de minas a céu aberto : caso da mina N5SUL em Carajás-PA

Costa, Marlene Furtado da January 2014 (has links)
Indicadores de qualidade ambiental tem o objetivo de medir as variações de qualidade atribuídas pelas atividades humanas sobre os ecossistemas ambientais. Muitos desses indicadores resultam da composição de variáveis distintas voltadas para objetivos específicos diversos. Definir quais são as variáveis mais importantes dentro de um processo de avaliação ambiental é, sem dúvida, um dos maiores desafios dos responsáveis por esse tipo de estudo. Dentro do processo produtivo, é muito comum que se construa um banco de dados com informações de monitoramento da qualidade ambiental, composto de informações que não se integram de modo simplificado, indicando ações de ajustes ou mitigação de possíveis impactos sobre a qualidade do compartimento ambiental estudado. Quando se trata da avaliação da qualidade das águas é incomparável o volume de informações que geralmente se processa para viabilizar a medição da qualidade. Comumente se utilizam medições quantitativas e qualitativas de parâmetros físico-químicos, biológicos e hidrobiológicos, associados a efeitos antrópicos, geológicos, geomorfológicos, conectados entre si, ou dispersos em medições individuais. Diante do desafio de definir um modo de avaliação específico para a qualidade das águas na área de influência direta de uma mina a céu aberto, o presente trabalho propõe uma metodologia que possa indicar quais roteiros devem ser seguidos para que uma avaliação ambiental da qualidade das águas garanta que as variáveis escolhidas sejam medidas e classificadas ao longo das diferentes fases operacionais de uma mina céu aberto, iniciando no planejamento, se estendendo durante as fases de implantação, operação e descomissionamento. É essencial que as diretrizes estabelecidas sejam prontamente utilizadas pelos gestores operacionais de modo que mudanças de procedimentos operacionais possam ser realizadas em função do objetivo principal da manutenção da qualidade ambiental. A proposta metodológica foi aplicada em um projeto de mineração a céu aberto, Mina de N5Sul no Complexo Minerador de Carajás, no estado do Pará, Brasil, sendo possível efetuar medições ambientais para uma mesma rede de monitoramento da qualidade das águas em três fases distintas: planejamento, instalação e operação, onde os resultados iniciais demonstraram que mudanças nos procedimentos operacionais foram aplicados com sucesso para a manutenção da qualidade das águas no entorno da mina. Além disso, é de fundamental importância que a rede de medições seja mantida até a fase de descomissionamento, pois com a composição do banco de dados de informações será possível avaliar de forma efetiva os impactos da operação de uma mina sobre a qualidade das águas do entorno ao longo do tempo de sua vida útil. / Environmental quality indicators are intended to measure quality changes attributed by human activities on environmental ecosystems. Many of these indicators results from the composition of different variables have focused on several specific objectives. Defining which are the most important variables within an environmental assessment process is undoubtedly one of the greatest challenges for those responsible for this type of study. Inside of the production process, it is very common to build a database with environmental quality monitoring information consists of information that are not integrated in a simplified manner, indicating needs of adjustments or mitigation of potential impacts on the quality of environmental compartment studied. When it comes to the assessment of water quality, is unparalleled the amount of information that usually is processed to enable the measurement quality. Commonly are used quantitative and qualitative measurements of physical and chemical parameters, biological and hydro-biological associated with anthropogenic effects, geological, geomorphological, connected with each other, or dispersed in individual measurements. Faced to the challenge of defining a specific evaluation mode for the water quality in the area of direct influence of an open pit mine, this paper proposes a methodology that can indicate which routes should be followed for an environmental assessment of water quality to ensure that the chosen variables are measured and classified throughout the different operational phases of an open pit mine, starting in the planning, extending during the deployment phase, operation and decommissioning. It is essential that the guidelines established can be readily used by operational managers, so that changes in operational procedures to occur based on the primary objective of maintaining environmental quality. The methodology was applied in a mining project in the open, N5Sul mine in Complex Miner Carajás, in the state of Pará, Brazil, where it was possible to make environmental measurements for the same quality monitoring network of water in three distinct phases : planning, installation and operation, where initial results showed that changes in operational procedures have been successfully applied to the maintenance of water quality in the vicinity of the mine. Besides, it is very important that the network is maintained until the decommissioning phase, as to the composition of bank information will be possible to assess effectively the impact of a mine operation on the quality of the surrounding water over time of its life.
243

Estimativa de recursos minerais e otimização de cava aplicados a um estudo de caso de uma mina de calcário / Mineral resource estimation and pit optimization applied to a case study of a limestone mine

Pereira, Paulo Elias Carneiro 08 March 2017 (has links)
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No. of bitstreams: 12 Dissertação - Paulo Elias Carneiro Pereira (1).pdf: 17644242 bytes, checksum: ab5fa50d404a6c4a211b84194b2443f2 (MD5) Dissertação - Paulo Elias Carneiro Pereira (2).pdf: 16660004 bytes, checksum: cf5e68fe373f5599a5185def4cd2dbc9 (MD5) Dissertação - Paulo Elias Carneiro Pereira (3).pdf: 16826382 bytes, checksum: d132111aea6718262b141b27469610cf (MD5) Dissertação - Paulo Elias Carneiro Pereira (4).pdf: 18524080 bytes, checksum: f823b94af26d66b0c3372283946a4faf (MD5) Dissertação - Paulo Elias Carneiro Pereira - 2017 (5).pdf: 18542428 bytes, checksum: fcbc6bc33ae4ce8f406d45226db9cec1 (MD5) Dissertação - Paulo Elias Carneiro Pereira - 2017 (6).pdf: 16491972 bytes, checksum: 700456f830447b127f5ebba098ae0777 (MD5) Dissertação - Paulo Elias Carneiro Pereira - 2017 (7).pdf: 17053967 bytes, checksum: 282d9a25fc2337ddbbe0d09a801e9821 (MD5) Dissertação - Paulo Elias Carneiro Pereira - 2017 (8).pdf: 13201210 bytes, checksum: c784be01d079249a502dd2dff455ca27 (MD5) Dissertação - Paulo Elias Carneiro Pereira - 2017 (9).pdf: 16669209 bytes, checksum: caf85a078ee9178fcd2989dca14ad6c6 (MD5) Dissertação - Paulo Elias Carneiro Pereira - 2017 (10).pdf: 16406537 bytes, checksum: 9019ab1ca27b30efd351da8c77f3ac36 (MD5) Dissertação - Paulo Elias Carneiro Pereira - 2017 (11).pdf: 3595306 bytes, checksum: 2cc84e96aca8430238c275c770941926 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-03-08 / A mining enterprise is composed of a set of successive and interdependent phases between them, which may or may not culminate in the exploitation of the mineral assets. The project begins with a Mineral Exploration phase, whose objective is to discover and subsequently evaluate the deposit for the feasibility of its extraction. This process involves setting the shape, dimensions and grades, resulting in a model that will be used to determine the recoverable reserves, that is, the economically usable part of the mineral resource, which will base the decision on the implementation or not of the enterprise, based mainly on technicaleconomic criteria. The elaboration of the physical form of the geological bodies that control the mineralization (geological model) and the estimation of the geological variables that characterize the quality of the different materials can be done by two approaches: by traditional or by geostatistical methods. The latter approach is currently being preferred, as it is a more accurate alternative and therefore, more reliable over traditional methods. The work uses indicator kriging (IK) and ordinary kriging (OK), both geostatistical tools, for the determination of the geological model and estimation of the geological variables (grades), respectively, of a limestone deposit located at Indiara city, Goiás State. Finally, from the obtained model the optimal limits of the extraction were established, based on the algorithm of Lerchs-Grossmann, that maximize the net present value of the enterprise. The results showed a significant deviation between themodel calculated by IK and the reality (samples), which can have as consequence the present spatial configuration of the sample data. The estimated geological variables also showed important deviations (overestimation and/or underestimation), particularly MgO oxide. The areas of occurrence of such deviations were coincident for all variables, which makes evident the existence of problems with the current sampling grid (spacing between samples and presence of very different sample supports), in such a way that it is recommended to collect additional samples, particularly with standardized supports. The optimal pit delimited a total reserve of 109,436,160.43 tons, with a total strip ratio of 0.13, which makes the venture, at first, attractive. This configuration, however, tends to be modified according to the collection of new geological evidence. / Um empreendimento mineiro é composto por um conjunto de fases sucessivas e interdependentes entre si, as quais podem culminar ou não na explotação do bem mineral. O projeto se inicia com uma fase de Exploração Mineral, cujo objetivo é descobrir e subsequentemente avaliar o depósito quanto à viabilidade de sua extração. Tal processo envolve estabelecer a forma, as dimensões e os teores, resultando em um modelo que será utilizado para a determinação das reservas lavráveis, ou seja, a parte economicamente aproveitável do recurso mineral, a qual fundamentará a decisão sobre a implantação ou não do empreendimento a partir de critérios principalmente técnico-econômicos. A elaboração do formato físico dos corpos geológicos que controlam a mineralização (modelo geológico) e a estimativa das variáveis geológicas que caracterizam a qualidade dos diferentes materiais podem ser feitas a partir de duas abordagens: por métodos tradicionais ou por geoestatísticos. Os últimos têm sido utilizados recentemente como uma proposta mais precisa em relação aosmétodos tradicionais. O trabalho utiliza a krigagem indicadora (KI) e a krigagem ordinária (KO), ambas ferramentas geoestatísticas, para a determinação do modelo geológico e estimativa das variáveis geológicas (teores), respectivamente, em um depósito de calcário situado no município de Indiara, estado de Goiás. Por fim, a partir do modelo obtido estabeleceu-se os limites ótimos da extração baseados no algoritmo de Lerchs-Grossmann, que maximizamo valor presente líquido do empreendimento. Os resultados mostraram um desvio significativo entre o modelo calculado pela KI e realidade (amostras), o que pode ter como consequência significativa a atual configuração espacial da amostragem. As variáveis geológicas estimadas também demonstraram desvios (sobrestimativa e subestimativa) importantes, particularmente o óxido MgO. As áreas de ocorrência de tais desvios foram coincidentes para todas as variáveis, o que torna evidente a existência de problemas com a atual malha de amostragem (espaçamento entre amostras e presença suportes amostrais muito diferentes), de tal forma que se recomenda a coleta de amostras adicionais, e de suportes padronizados. A cava ótima delimitou uma reserva total de 109.436.160,43 toneladas, com uma relação estéril-minério (REM) total de 0,13, o que torna o empreendimento, a princípio, atrativo. Tal configuração, entretanto, tende a ser alterada conforme a coleta de novas evidências geológicas.
244

Penetração de materiais resinosos em lesões de erosão, com e sem condicionamento prévio do esmalte: estudo in vitro / Resin based materials penetration in eroded lesions, with and without enamel conditioning: an in vitro study

Franciny Querobim Ionta 09 April 2014 (has links)
Uma alternativa de tratamento para as lesões iniciais de erosão é a aplicação de materiais resinosos. Porém, não há estudos que avaliem a penetração desses materiais no interior da lesão de erosão, o que poderia interferir em sua adesão e efeito. Portanto, o objetivo do presente estudo foi avaliar a penetração do infiltrante, adesivos e selante de fossas e fissuras, sobre lesões iniciais de erosão, com e sem condicionamento da superfície de esmalte. Utilizando um protocolo in vitro, foram estudados os tipos de tratamento em 5 níveis (Adhese®- sistema adesivo autocondicionante de 2 passos, Tetric N-Bond®- sistema adesivo convencional de 2 passos, Single Bond®- sistema adesivo convencional de 2 passos, Helioseal Clear®- selante resinoso e Icon®- infiltrante) e o tipo de condicionamento do esmalte em 2 níveis (com e sem). Os materiais foram corados com 0,02 mg/ml de solução etanólica de isotiocianato de tetrametilrodamina. Para o desenvolvimento da lesão inicial de erosão, 75 blocos de esmalte bovino (4 x 4 mm) foram imersos em HCl 0,01 M, pH 2,3, durante 30 segundos. Posteriormente, em metade da superfície dos blocos foram aplicados os materiais (marcados com rodamina), seguindo as instruções dos fabricantes. Na outra metade, os materiais foram aplicados da mesma forma, mas sem o condicionamento prévio do esmalte. Os blocos foram avaliados por Microscopia Confocal de Varredura a Laser nos modos de reflexão e fluorescência. Nas imagens geradas foram mensuradas a profundidade de desmineralização, a penetração e a espessura dos materiais, por meio do software ImageJ. Os dados foram analisados pelo teste ANOVA a dois critérios e teste de Tukey (p<0,05). Independentemente do material utilizado, o condicionamento do esmalte resultou em maior profundidade de desmineralização, penetração e espessura dos materiais, do que a situação sem condicionamento (p<0,05). A profundidade de desmineralização foi semelhante para os diferentes materiais (p>0,05), com exceção do Icon® (maior desmineralização) em relação ao Adhese® (p<0,05). Para a penetração dos materiais no esmalte, o Icon® seguido do HeliosealClear® apresentou maior profundidade de penetração, com diferença significativa entre eles (p<0,05) e não houve diferença para o Adhese®, Tetric N-Bond® e Single Bond® (p>0,05). A aplicação do HeliosealClear® resultou em maior espessura de material seguido pelo Icon®, com diferença estatística significativa entre eles (p<0,05), sendo que os outros materiais em estudo apresentaram espessura menor, sem diferença significativa entre eles (p>0,05). Concluiu-se que para todos os materiais resinosos estudados, o condicionamento prévio da superfície de esmalte aumentou a penetração do material no interior da lesão, sendo que o material com maior penetração foi o infiltrante (Icon®). / The application of resin based materials is an alternative of treatment for eroded lesions. Nevertheless, there are no studies about the penetration of these materials into eroded lesion, which might affect its adhesion and effect. Therefore, the purpose of this study was to evaluate the penetration of infiltrant, adhesives and pit and fissure sealant on initial eroded lesion, with and without prior enamel surface conditioning. By using an in vitro protocol, types of treatment were studied at 5 levels (AdheSE®- two-steps self-etching adhesive system, Tetric N-Bond®- two-steps conventional adhesive system, Single Bond® - two-steps conventional adhesive system, Helioseal Clear®- resin sealant and Icon®-infiltrant) and type of enamel conditioning in two levels (with and without). The materials were stained with 0.02 mg/ml ethanolic solution of tetramethylrhodamine isothiocyanate. Bovine enamel samples (4 x 4 mm) were immersed in 0.01 M HCl, pH 2.0, for 30 seconds in order to produce initial eroded lesions. Afterwards, the materials (previously marked with rhodamine) were applied on half of sample enamel surface following the manufacturers instructions. On the other half of sample enamel surface, the materials were applied following the same instructions but without prior enamel surface conditioning. The enamel samples were evaluated by Confocal Laser Scanning Microscope using reflection and fluorescence modes. Depth of demineralization, depth of penetration and thickness of the materials were measured using ImageJ software. Data were analyzed by two-way ANOVA and Tukey test (p<0.05). Regardless of the material, enamel conditioning resulted in higher depth of demineralization, depth of penetration and material thickness than without conditioning (p<0.05). Depth of demineralization was similar on the materials (p>0.05), except Icon® (higher demineralization) compared to AdheSE® (p<0.05). Icon® followed by Helioseal Clear® showed higher penetration depth in enamel, with significant difference between them (p<0.05) and no difference was found among AdheSE®, Tetric N-Bond® and Single Bond® (p>0.05). The application of Helioseal Clear® resulted in increased thickness of material followed by Icon®, with statistically significant difference (p<0.05). The other studied materials showed less thickness, without significant difference among them (p>0.05). It was concluded that for the studied resin based materials, the prior enamel surface conditioning increased penetration of the material into the eroded lesion and the infiltrant (Icon®) presented the highest penetration.
245

Eco-innovation : tools to facilitate early-stage workshops

Jones, Elies January 2003 (has links)
This thesis presents research carried out into the use of creative tools at the early stages of eco-innovation. Eco-innovation is a practical approach aiming to develop new products and processes which significantly decrease our impact on the environment. Designers are trained to develop profitable products that increase production and consumption. Eco-innovation is a new discipline in which designers can radically reduce the environmental burdens of production and consumption through the innovation of new types of products and services. The main aim of this research was to develop an approach that would promote significant environmental improvements whilst remaining a practical, design-focused discipline. Problems and under-investigated aspects of eco-innovation were identified: • Creative approaches at early stages of eco-innovation were under-investigated and few tools had been developed for use at the early stages. • Empirical design research techniques had rarely been used to assess new eco-innovation tools or to inform their subsequent development. The focus of the research work was the development and testing of tools to facilitate workshops at the early stages of eco-innovation. Not only was the goal to facilitate the generation of radical ideas but also to ensure that these were developed into appropriate solutions having the potential to be taken up in industry. The development of the tools was based on literature research, worked examples and interviews. The tools were tested in controlled workshop experiments and the results were analysed using various empirical techniques. First, an idea-recording technique to improve the efficiency of generating and harvesting ideas in a team design process was developed. This novel tool was called the Product Ideas Tree (PIT) diagram. The tool was tested for its ability to facilitate design workshops. Secondly, a structured approach to innovation - the theory of inventive problem solving (TRIZ) - was investigated. Worked examples using some of the tools from TRIZ were presented and a limited number of tools were selected and simplified for testing in team design workshops. The PIT diagram and TRIZ tools experiments established which attributes of the tools and approaches were most beneficial. The development and testing of these specific tools provided the following general contributions to eco-innovation: • A model for eco-innovation that describes the factors influencing the discipline and the attributes of good practice. • A recommended process to transform radical ideas into appropriate solutions to improve their potential to be taken up in industry. • General insights into the use of tools in early-stage workshops such as: tool selection, integration into existing processes, system-level problem solving and providing thematic information. • Suggested improvements for testing tools in controlled workshop experiments.
246

Hittite Mortuary Practices

Axelsson, Anton January 2017 (has links)
The Hittite burial material consists of a very heterogeneous material. The material shows some shared aspects between the different cemeteries and their grave types. However, this material lacks previous extensive comparative studies in central Anatolia. This study aims to problematize this funerary material, by re-evaluating the previous interpretation and by creating links between the different types of material and the cemeteries it was found in. This will be achieved by analyzing four different categories of Hittite graves from the three cemeteries: Osmankayasi, Gordion and Ilica. The total material consists of 268 graves: 91 from Osmankayasi, 46 from Gordion and 131 from Ilica. The material was originally excavated and published during the fifties and sixties by the three archaeologists Kurt Bittel, Machteld Mellink and Winfried Orthmann. The burial material will be analyzed to establish parallels and differences between the three sites, their materials and grave categories. Literary sources and empirical data will be used to supplement previous research but also the new interpretations discussed in this thesis. Keywords: Hittite, cemeteries, mortuary practices, Osmankayasi, Gordion, Ilica, cremations, pithos burials, pit graves, cist-graves, ethnicity, status, equids / Det Hettitiska begravnings materialet består av ett väldigt heterogent material. Materialet visar ändå vissa delade aspekter mellan de olika gravfälten och gravtyperna. Dock saknar detta material tidigare omfattande komparativa studier i centrala Anatolien. Denna studie avser att problematisera detta gravmaterial, genom att skapa kopplingar mellan de olika typerna av materialet och mellan de utvalda platserna som det återfanns i. Detta mål avses att uppnås genom att analysera fyra olika typer av Hettitiska gravar från de tre platserna Osmankayasi, Gordion och Ilica. Det totala grav antalet består av 268 gravar: 91 från Osmankayasi, 46 från Gordion och 131 från Ilica. Materialet var ursprungligen utgrävt och publicerat under femtio och sextio-talet av de tre arkeologerna Kurt Bittel, Machteld Mellink och Winfried Orthmann. Gravmaterialet kommer att analyseras för att etablera paralleller mellan de tre platsernas material och dess gravkategorier. Litterära källor och empiriskdata kommer att användas för att komplettera den tidigare forskningen och de nya tolkningarna i denna studie.
247

Avaliação da atividade antifúngica de óleo essencial de orégano (Origanum vulgare) nanoemulsionado e estudo de caso em queijo Minas Padrão / Evaluation of antifungal activity of nanoemulsions encapsulating oregano essential oil and case study in Minas Padrão cheese

Carolina Maria Bedoya Serna 06 May 2015 (has links)
Este trabalho de Mestrado teve por objetivo avaliar a atividade antifúngica in vitro e em queijo Minas Padrão de duas formulações (A e B) de nanoemulsões encapsulando óleo essencial de orégano (Origanum vulgare) produzidas pelo método da temperatura de inversão de fases (método PIT). Cladosporium sp., Fusarium sp. e Penicillium sp. foram os fungos identificados nas amostras de queijo Minas Padrão deteriorados. Tais cepas foram utilizadas na avaliação da atividade antifúngica in vitro e em queijo Minas Padrão do óleo de orégano nanoemulsionado. Nos testes in vitro foram determinadas as concentrações mínimas inibitórias (CMI) do óleo essencial de orégano puro e nanoemulsionado sobre o Cladosporium sp., Fusarium sp. e Penicillium sp. Foram utilizadas fatias de queijo Minas Padrão para avaliar o efeito inibitório das nanoemulsões contendo óleo essencial de orégano. Por último foi avaliado o efeito inibitório das nanoemulsões durante o processo de maturação de queijos Minas Padrão. Determinaram-se valores de CMI para óleo essencial puro de 0,2; 0,3 µg/ml para Fusarium sp. e Penicillium sp., respectivamente. Enquanto para as duas formulações de nanoemulsão; os valores de CMI dependeram da quantidade de óleo essencial de orégano que estava contido nelas, obtendo-se valores de 0,26; 0,11 e 1,62 µg/ml para a formulação A de óleo de orégano nanoemulsionado sobre Cladosporium sp., Fusarium sp. e Penicillium sp., respectivamente, e CMIs de 0,32; 0,1 e 0,8 µg/ml para a formulação B de nanoemulsão sobre os mesmos gêneros de fungos. Os ensaios nas fatias de queijo evidenciaram que o efeito das CMIs, quando aplicadas na matriz alimentícia, foi nulo, permitindo o desenvolvimento normal dos fungos avaliados, da mesma forma se determinou a importância da atividade de água no crescimento fúngico. Já nos queijos em ambiente de maturação o efeito inibitório do óleo de orégano foi pouco satisfatório, o que indicou a importância do controle dos demais parâmetros ambientais no ambiente de maturação. Pode-se concluir que o óleo essencial de orégano nanoemulsionado apresentou efeito inibitório contra os gêneros de fungos avaliados. Quando controlados parâmetros ambientais como temperatura de armazenamento e atividade de água, seu efeito inibitório pode ser amplamente melhorado, apresentando-o como potencial alternativa na conservação dos alimentos. / This Master Thesis aimed to evaluate the in vitro antifungal activity and in Minas Padrão cheese of two formulations (A and B) of nanoemulsions encapsulating essential oil of oregano (Origanum vulgare) produced by the method of phase inversion temperature (PIT method). Cladosporium sp., Fusarium sp. and Penicillium sp. fungi were identified in deteriorated cheese samples. These strains were used in the evaluation of antifungal activity of oregano essential oil nanoemulsions, both in vitro and in cheese. Minimum inhibitory concentrations (MIC) of essential oil of pure oregano oil and nanoemulsions were determined. Cheese slices were used to evaluate the inhibitory effect of nanoemulsions containing essential oil of oregano. Finally the inhibitory effect of encapsulated oregano oil was tested during cheese ripening. MIC values determined for pure essential oil were 0.20 and 0.3 µg/ml for Fusarium sp. and Penicillium sp., respectively. As for the two nanoemulsion formulations, MIC values depended on the amount of essential oil of oregano which was contained therein, and the values for formulation A were 0.26, 0.11 and 1.62 µg/ml for Cladosporium sp., Fusarium sp. and Penicillium sp, respectively. For formulation B, the values of MIC were 0.32, 0.10 and 0.80 µg/ml. The tests on the cheese slices showed that the effect of MIC when applied in the food matrix was null, as the fungi growth was not avoided. As for the tests during cheese ripening, the inhibitory effect of oregano oil in nanoemulsions was unsatisfactory, which indicated the importance of controlling other environmental parameters in the maturation chamber. It can be concluded that the nanoemulsions of essential oil presented inhibitory effect against the genera of fungi evaluated. Controlled environmental parameters such as storage temperature and water activity, its inhibitory effect can be highly improved, and the nanoemulsions of oregano oil can be seen as a potential system for food preservation.
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Studium redoxních a adsorpčních vlastností žlučových kyselin na rtuťové visící kapkové elektrodě / Study of redox and adsorption features of bile acids on hanging mercury drop electrode

Yershova, Polina January 2020 (has links)
Bile acids are the end products of cholesterol metabolism and are important biological surfactants. The curved shape of their chains allows the cyclization of molecules, and the formation of a supramolecular structure. The goal of this thesis was to study the electrochemical and adsorption behavior of selected bile acids: lithocholic, deoxycholic and cholic acids. The measurements were carried out in the medium Brittonův-Robinson buffer:methanol in the ratio 9:1 using cyclic voltammetry and AC voltammetry methods and measuring the dependence of the differential capacitance Cd on the applied potential E. A hanging mercury drop electrode was used as a working electrode. The measurements showed that bile acids are adsorbed on the surface of the electrode and organizing themselves in self assembled monolayers (SAM). In our case we have observed formation of 2D condensed layers as specific form of SAM. Transfer techniques were used to demonstrate bile acid adsorption. A study of the behavior of lithocholic acid as a function of different pH values showed that only at pH 10.0 to 12.0 2D 2D condensation occurs, i. e. that at pH values in the range of 2.0 to 9.0 it is another type of adsorption. On AC voltammograms, there are a maximum of two areas in which peaks occur: the first is around -0.2 V and the...
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Comparing the pitting corrosion behavior of prominent Zr-based bulk metallic glasses

Gostin, Petre Flaviu, Eigel, Dimitri, Grell, Daniel, Eckert, Jürgen, Kerscher, Eberhard, Gebert, Annett, Scudino, S., Yang, C., Eckert, J. 17 April 2020 (has links)
Five well-known Zr-based alloys of the systems Zr–Cu–Al–(Ni–Nb, Ni–Ti, Ag) (Cu 5 15.4–36 at.%) with the highest glass-forming ability were comparatively analyzed regarding their pitting corrosion resistance and repassivation ability in a chloride-containing solution. Potentiodynamic polarization measurements were conducted in the neutral 0.01 M Na₂SO₄ 1 0.1 M NaCl electrolyte and local corrosion damages were subsequently investigated with high resolution scanning electron microscopy (HR-SEM) coupled with energy dispersive x-ray spectroscopy (EDX). Both pitting and repassivation potential correlate with the Cu concentration, i.e., those potentials decrease with increasing Cu content. Pit morphology is not composition dependent: while initially hemispherical pits then develop an irregular shape and a porous rim. Corrosion products are rich in Cu, O, and often Cl species. A combination of low Cu and high Nb or Ti contents is most beneficial for a high pitting resistance of Zr-based bulk metallic glasses. The bulk glassy Zr₅₇Cu₁₅.₄Al₁₀Ni₁₂.₆Nb₅ (Vit 106) and Zr₅₂.₅Cu₁₇.₉Al₁₀Ni₁₄.₆Ti₅ (Vit 105) alloys exhibit the highest pitting resistance.
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Geofyzikální průzkum poddolovaného území v Lukavici u Chrudimi / Geophysical survey of undermined area in Lukavice near Chrudim

Slavíčková, Michaela January 2010 (has links)
Lukavice village is located in Eastern Bohemia and it is known for its historical pyrite mining. The first mention of mining comes from the beginning of 17th century. The mines were abandoned in 1892 due to a significant depletion of the upper parts of the deposit and also because of the competition of cheaper pyrite from abroad. Old mine workings were often backfilled incompletely and their exact location is unknown. The occurrence of empty mine workings under the roads in the village centre could cause a collapse of the ground under the weight of heavy trucks which carry through Lukavice village aggregate from the nearby quarry. The aim of geophysics was to determine the thickness of dump material (seismics), subsidence monitoring in the village centre (repeated levelling) and the principal aim was to locate old mine galleries and shafts (gravity survey). Gravity measurements did not prove the presence of empty mine workings under the main road at the village centre. Most pronounced negative Bouguer anomaly, which occurs in the vicinity of Bartolomějská jáma schaft, may be caused by higher degree of alteration of underlying porphyroids. According to historical maps and photos we determined approximate location of the former water pit Vilemina. For the determination of the exact position of the...

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