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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.
101

Contribuição ao estudo da aplicação de materiais alternativos nos compositos a base de cimento Portland : uso de grãos de polipropileno reciclado em substituição aos agregados do concreto / Contribution to the study of the application of alternative materials in the composites based on Portland cement : use of polypropylene grains recycled in substitution to the aggregates of the concrete

Coelho, Rivaldo Teodoro 25 February 2005 (has links)
Orientador: Vitor Antonio Ducatti / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-04T21:28:54Z (GMT). No. of bitstreams: 1 Coelho_RivaldoTeodoro_M.pdf: 3250291 bytes, checksum: b2bb15d8a20d152e3701aa42810cff85 (MD5) Previous issue date: 2005 / Resumo: O principal objetivo desta dissertação foi a determinação das principais propriedades mecânicas de um compósito à base de cimento Portland CP-V-ARI (alta resistência inicial) tendo como agregado os grãos reciclados aglutinados de polipropileno (GRAP). A escolha do plástico se deve ao fato de que é um dos principais materiais utilizados pela indústria em geral sendo descartado em média na proporção de 7% do peso e 25% do volume do lixo urbano metropolitano e índice de reciclagem de 17,5%. No caso específico do polipropileno a proposta de seu uso deveu-se ao fato dele ser um dos três plásticos mais consumidos e descartados no Brasil, tornando-se oportuno o desenvolvimento de alternativas para a reciclagem deste material como material para a construção civil como agregado para o concreto. Neste estudo, foram realizados ensaios com base nas normas da ABNT ¿ Associação Brasileira de Normas Técnicas, para a caracterização do concreto no estado endurecido, principalmente para a determinação das resistências à compressão axial e diametral, resistência à tração na flexão e módulo de elasticidade secante. Os resultados obtidos em ensaios com misturas com e sem agregados minerais (substituição) foram satisfatórios permitindo o desenvolvimento de vários concretos com resistência à compressão axial (fcj) adequado para a produção de elementos pré-fabricados, concretos porosos adequados para drenagens e enchimento de lajes, painéis, blocos de concreto e grãos de polipropileno mineralizados com a pasta de cimento, dentre outras aplicações. Houve uma redução superior a 30% do peso final do concreto por meio da redução da massa específica. O novo concreto também se mostrou extremamente dúctil, adequado para especificações de absorção de impactos. Através dos resultados desta pesquisa pôde-se concluir que é perfeitamente viável o uso do concreto com grãos de polipropileno em substituição aos agregados minerais na construção civil / Abstract: The main objective of this dissertation was the determination of the main mechanical properties of a composite based on Portland cement CP-V-ARI (high initial resistance) tends as aggregate the grains recycled agglutinated of polypropylene (GRAP). The choice of the plastic is due to the fact that it is one of the main materials used by the industry in general being discarded on average in the proportion of 7% of the weight and 25% of the volume of the metropolitan urban garbage and index of recycling of 17,5%. In the specific case of the polypropylene the proposal of his use was due to his fact to be one of the three plastics more consumed and discarded in Brazil and that indicators reveal the need to develop alternatives for the recycling of this material in the engineering and in the building site as an aggregate for the concrete seeking the partial or total substitution of minerals aggregates. In this study, rehearsals were accomplished with base in the norms of ABNT - Brazilian Association of Technical Norms, for the characterization of the concrete in the hardened state, mainly for the determination of the resistances to the axial and diametrical compression, resistance to the traction in the flexing and module of drying elasticity. The results obtained in rehearsals with mixtures with and without aggregates minerals (substitution) they were satisfactory allowing the development of several concretes with resistance to the axial compression (fcj), through appropriate mixtures to the production of prefabricated elements, an appropriate porous concrete for drainages and stuffing of flagstones and polypropylene grains mineralized with the cement paste, among other applications. There was a superior reduction to 30% of the final weight of the concrete through the reduction of the specific mass. The new concrete was also shown extremely ductile, appropriate for specifications of absorption of impacts. Through the results of this research it could be concluded that it is perfectly viable the use of the concrete with polypropylene grains in substitution to the mineral aggregates in the building site / Mestrado / Edificações / Mestre em Engenharia Civil
102

Utilização da radiação ionizante na reciclagem de pneus inservíveis de automóvel e sua destinação ambiental adequada / Use of ionizing radiation in the recycling of unserviceable tires of automotive and its adequate environmental disposal

SOUZA, CLECIA de M. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:42:28Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:02:09Z (GMT). No. of bitstreams: 0 / O objetivo deste trabalho foi utilizar a radiação ionizante na reciclagem de pneus inservíveis de automóvel. As amostras de borracha de pneus inservíveis foram irradiadas com doses de radiação de 200, 400 e 600kGy, em um acelerador de elétrons. Posteriormente, elas foram caracterizadas por termogravimetria (TG), calorimetria exploratória diferencial (DSC), ensaios mecânicos de tração, espectrofotometria de infravermelho por transformada de Fourier (FTIR) e microscopia eletrônica de varredura (MEV). Por TG foi possível observar os efeitos da radiação na perda de massa do material. Por DSC observou-se as curvas exotérmicas associadas à decomposição e valores de variação de entalpia (ΔH). Foram estudadas as propriedades mecânicas das amostras da matriz elastomérica com o pó de pneu inservível e verificado o seu comportamento frente à radiação ionizante. Os espectros FTIR foram obtidos na região de 4000 650cm-1. Observou-se que não foi possível observar alteração nos picos devido à irradiação. Nos ensaios por MEV as micrografias foram ampliadas de 32 vezes até 1000 vezes e observadas nos tamanhos de 1mm até 20μm. Observou-se nas doses de 200 e 400kGy, rugosidades correspondentes a quebras ou rupturas, possivelmente causadas pela radiação. Na dose de 600kGy, foi possível observar cavidades causadas pela radiação. Observou-se que para todas as doses houve degradação. Para as amostras dos corpos de prova sem pó e com pó de pneus inservíveis com 10%, 30% e 50% de pó as micrografias foram observadas nas ampliações de 100μm e 200μm. Também foi possível observar a incorporação do pó de pneus inservíveis de automóvel na matriz elastomérica das amostras não irradiadas e irradiadas. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
103

Modelagem e simulação de sistema de embalagem e pesagem de material particulado em pó. / Modeling and simulation of a packaging and weighing system of granulated powders.

Rafael Couto Rodrigues de Oliveira 08 August 2014 (has links)
Esse trabalho é dedicado ao desenvolvimento de um simulador para sistema de pesagem e embalagem de produto em pó granulado. Tal simulador reproduz a variabilidade de peso dos cartuchos observados em um sistema de embalagem real. Para esse desenvolvimento foram aplicadas técnicas de Identificação de Sistemas para obter o modelo determinístico do processo e conceitos de Processos Estocásticos para reproduzir as perturbações. O simulador tem como objetivo a avaliação de propostas de melhorias nesse sistema de pesagem, visando reduzir o sobrepeso médio e a quantidade de cartuchos rejeitados por subpeso, denominados de scraps, diminuindo consequentemente as perdas monetárias do processo industrial de embalagem de produtos granulados, com grande potencial de reaplicação para outros tipos de produtos industrializados e sistemas de pesagem. O desempenho do simulador é muito bom, uma vez que as oscilações observadas nos pesos dos cartuchos, devido à variação de densidade, são bem reproduzidas. Portanto as principais contribuições desse trabalho são: 1) o uso de uma abordagem estatística e inovadora para modelar as perturbações, evitando o estudo profundo de suas causas, alcançando um modelo preciso, que simula resultados de sobrepeso e número de cartuchos rejeitados bem próximo da realidade; 2) identificação e quantificação de melhorias no sistema de pesagem e embalagem, sem a necessidade de altos investimentos, dando a opção de decisão de quais melhorias realmente serão implementadas; 3) sobrepeso e scrap normalmente estão entre as três principais perdas monetárias das indústrias que produzem produtos embalados por peso e esse simulador representa uma forma de redução significativa dessas perdas, trazendo uma grande vantagem competitiva em um mercado cada vez mais acirrado. / This work describes the development of a simulator for a packing and weighing system of granulated powder. This simulator reproduces the weight variability of observed cartons in a real packing system. In this development, System Identification techniques were used to obtain the deterministic part of the model and Stochastic Processes to reproduce disturbances. Its objective is to evaluate proposed improvements in the packing and weighing system, aiming at reducing the overweight average and the quantity of rejected cartons by underweight, denominated scraps, cutting down consequently the monetary losses of the granulated product packing process in the industry, with great reapplication potential to other kind of industry products and weighing systems. The simulator performance is very satisfactory, once the oscillations observed in the carton weights, due to powder density variability, are well reproduced. Hence, the main contributions of this work are: 1) use of a statistical and innovative approach to model the disturbances, avoiding a deep study of their causes, achieving a model that provided precise simulated overpacking and scrap results when compared to reality; 2) identification and quantification improvements of the weighing and packing system, with no large investment, giving the option of decision of which improvement will be actually implemented; 3) overweight and scrap are among the three main monetary losses in the industries that make products packed in weight and so this simulator of a packing and weighing system of granulated powder represents a way of reducing significantly these losses, bringing a big competitive advantage in a demanding market.
104

Ocenění podniku v oboru zpracování druhotných surovin / Valuation of a company operating in secondary sources processing

Nistorenco, Taisia January 2017 (has links)
This diploma thesis deals with valuation of a Czech company operating in the field of metal scrap recycling. The goal of the thesis is to find market value of the company with a purpose of sale to an identified rational investor. The thesis opens with a presentation of company s main business activities. It is followed by the strategic analysis of its external and internal potential, which covers the development of metal scrap market and the company s competitive position on it. Financial analysis investigates financial health of the company and compares its financial performance with that of company s competitors. In the fourth chapter I forecast the development of the main value generators: sales, profit margin, working capital and long-term assets. This forecast is later incorporated into the financial plan of the company. Last chapter is dedicated to company s valuation according to DCF method and market comparison method. As a conclusion to the work I analyze the results of the valuation and income generation capacity of the company.
105

Lean Manufacturing Model Adapted for Waste Reduction in Peruvian Condiment Production Agri-Businesses

Mesones-Guillén, Axel, Palacios-Jesús, Lizeth, Carvallo-Munar, Edgardo, Salas-Castro, Rosa, Cardenas-Rengifo, Luis 01 January 2021 (has links)
El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / The Peruvian export supply is primarily based on the segment of dressings and condiments. This paper seeks to adapt lean manufacturing tools using Poka-Yoke techniques and process standardization, which may align with existing processes to prevent production errors. This combination of tools is expected to reduce the percentage of waste generated throughout the condiment production process. Subsequent to an initial evaluation of the current method combined with the application of both the tools, 11.4% waste reduction was ultimately reported. / Revisión por pares
106

Finanční řízení stavební zakázky z pohledu dodavatele / Financial Managment of a Construction Contract from the Perspetive of A Contractor

Rusnok, Jakub January 2018 (has links)
The aim of this thesis is to introduce the topic „Financial management of a construction contract from the perspective of a contractor“ and to point at possibilities and process of contract funding. This thesis also deals with risks which can affect funding of contract and based on this analysis recommends possible arrangements.
107

Návrh automatického lisu / Design of automatic press

Ujčík, Miroslav January 2021 (has links)
The master's thesis deals with the design of a press, which will be part of a robotic workplace. This workplace is designed for a company operating as a subcontractor for the automotive industry, for which automation is one of the most important processes of development and increasing labor productivity. The robotized cell is part of a line for heat treatment of plastic tube semi-finished products. The cell itself is used to press the conical extension of the pipe ends using a steel mandrel. In order to manipulate the parts, the corresponding end effectors of robots are designed in the work, which safely load and remove parts from the automated press. Design and control calculations are supplemented by finite element strength analysis in Solidworks. A drawing documentation is also made in this program. The work is performed with regard to the requirements of technologists and the quality department.
108

Návrhy na zlepšení řízení jakosti ve firmě / Quality management proposals in the company

Malá, Alena January 2008 (has links)
The thesis analyses a quality management process in a manufacturing company and offers suggestions and recommendations for improvement. This thesis should assist in more effective quality management process and help company to get a competitive advantage with using TQM method.
109

Studium vlivu požárů skládek komunálních a průmyslových odpadů na kontaminaci životního prostředí, produkty hoření pryže a halogenovaných polymerů / Study of the influence of fires of municipal and industrial waste landfills on the enviromental contamination, the combustion products of rubber and halogenated polymers

Sikora, Henryk January 2014 (has links)
This thesis deals with the issue of fires of municipal and industrial wastes, particularly of rubber and halogenated polymers. When these materials burn, significant amount of harmful substances liberate into environmental compartments. Analysis of samples subjected to thermal decomposition in laboratory conditions explored formation of characteristic compounds in dependence on conditions of combustion. Samples of air, water and soil taken from real fires that occurred between the years 2007 – 2011 in the region of Western Bohemia monitored spreading of these substances into the environment. Majority of these samples were analysed by the means of gas chromatography with mass spectrometric detection. Additionally the effect of extinguishing methods and use of fire extinguishers on formation and spreading of combustion products was studied, especially in soil and in water sources.
110

Ökonomische Analyse der Rückgewinnung von hochwertigen Metallen aus elektrischen und elektronischen Altgeräten in Deutschland

Greif, Steffi 03 December 2009 (has links)
Die vorliegende Ausgabe beschäftigt sich mit dem Thema „Ökonomische Analyse der Rückgewinnung von hochwertigen Metallen aus elektrischen und elektronischen Altgeräten in Deutschland“. Elektro- und Elektronikgeräte sind aus dem täglichen Leben nicht mehr wegzudenken; die Unternehmen entwickeln und produzieren immer leistungsfähigere Produkte, wobei durch die immer schnelleren und kurzlebigeren Innovationszyklen die Abfallberge ausgedienter Elektro(nik)geräte beständig wachsen. Mit Inkrafttreten des Elektro- und Elektronikgerätegesetz am 24. März 2005 werden alte Elektro(nik)geräte zukünftig getrennt gesammelt und weitgehend verwertet. Neu ist, dass die Hersteller mehr Verantwortung für ihre Produkte übernehmen und zur Verwertung der getrennt gesammelten Elektro- und Elektronik-Altgeräten verpflichtet sind. Das Elektro- und Elektronikgerätegesetz geht zum einen aus der europäischen Richtlinie über die Entsorgung von Elektro- und Elektronik-Altgeräten (WEEE) und zum anderen aus der europäischen Richtlinie über die Verwendung bestimmter gefährlicher Stoffe in Elektro- und Elektronikgeräten (RoHS) hervor und gilt als Reaktion auf die wachsenden Elektro(nik)schrott-Berge. Für die Unternehmen der Entsorgungs- und Recyclingbranche ergeben sich mit diesen gesetzlichen Neuerungen neue Chancen auf Weiterentwicklung ihres Geschäftsfeldes. Besonderes Augenmerk gilt den Demontageunternehmen, mit deren Hilfe erst die gesetzlichen Forderungen, hinsichtlich der zu erzielenden Rückgewinnungsquoten und der notwendigen selektiven Behandlung einiger Baugruppen, erfüllt werden können. Die Rückgewinnung hochwertiger Metalle aus Elektro(nik)schrott bedarf im Hinblick der Preissteigerungen auf den Rohstoffmärkten höchster Priorität. Mit Etablierung eines Sekundärrohstoffmarktes kann ein rohstoffarmes Land wie Deutschland der Abhängigkeit des Importes von Primärrohstoffen signifikant entgegenwirken.

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