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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.
1

Surface mine power system design, with special reference to harmonic pollution

Benatmane, M. January 1985 (has links)
No description available.
2

Technologické ověření rýpadel v oblasti zemních prací. / Technology verification excavators in earthworks

FIKOTOVÁ, Petra January 2013 (has links)
This thesis on the topic of Technology verification in the field of wheel excavators and its excavations in the first general part deals with the analysis of the work carried out on the construction site. Wheel excavator analysis tools have been developed and used. The study included ?wheel excavators and the technical parameters and analysis with the binding on the size category of wheel excavators?. The second part of the work deals with the evaluation of the results of the data collection for the determination of the actual times of working wheel excavators; and resultant cycles, depending on the work carried out. In addition, there are factors that affect the intended performance wheel excavators and how it works in the implementation of specific operations. Part of the work is the determination of the values of the correction coefficients for the calculation of the actual performance and the determination of the actual wheel excavators, and subsequent analysis of the excavators? performance dependent upon carried out working operations. In conclusion, on the results gained from the analytical process, proposals and guidelines for the optimal use of wheel excavators within the construction industry have been attained.
3

Desenvolvimento de um modelo de dimensionamento de equipamento de escavacao e de transporte em mineração

Racia, Ismael Momade January 2016 (has links)
O motivo da dissertação “Desenvolvimento de um Modelo de Dimensionamento de Equipamentos de Escavação e de Transporte” surgiu da necessidade de apoiar no processo de decisão de dimensionamento dos principais equipamentos de mineração. Este trabalho apresenta um modelo simples e direto para dimensionar os equipamentos principais de mineração (escavadeiras e caminhões) através de uma rotina criada denominada EXCEsimulator, concebido para o cálculo da capacidade das caçambas das escavadeiras, do número dos equipamentos de escavação e de transporte, bem como os tempos de espera das unidades de transporte em carregar. Para tal, definem-se os parâmetros de produtividade e caraterísticas dos equipamentos; calcula-se aplicando um modelo determinístico de produção; e faz-se o levantamento de equipamentos existentes no mercado, reunindo as suas características e serviços prestados pelos representantes ou fabricantes das marcas. Para demostrar a funcionalidade do modelo desenvolvido, o presente trabalho demonstrou, através de um estudo de caso, o dimensionamento de uma frota de carregamento e transporte para uma mineração a céu aberto utilizando indicadores de produção, e uma comparação entre o uso de equipamentos de pequeno e grande porte no aspeto da demanda de equipamento. O estudo foi desenvolvido a partir de uma empresa de mineração hipotética baseada em dados realista. O modelo desenvolvido é aplicável a qualquer tipo de equipamento de escavação e de transporte, independente do seu porte e capacidade de produção. Como conclusão, pretende-se com esta dissertação fornecer uma ferramenta útil para o apoio à decisão de dimensionamento de equipamentos e frotas de escavação e de transporte capaz de suprir a necessidade de uma consulta de mercado. / The reason for the dissertation "Development of an Estimating Model for Excavation and Transport Equipment" arose from the need to support the decision-making process for the size of the main mining equipment. This work presents a simple and direct model for sizing the main mining equipment (excavators and trucks) through a routine created called EXCEsimulator, designed to calculate the capacity of excavator buckets, number of excavation and transport equipment, and As the waiting times of the transport units on loading. For this, the parameters of productivity and characteristics of the equipment are defined; Is calculated by applying a deterministic model of production; And it is made the survey of existing equipment in the market, gathering its characteristics and services provided by the representatives or manufacturers of the brands. To demonstrate the functionality of the developed model, the present study demonstrated, through a case study, the design of a loading and transport fleet for open pit mining using production indicators, and a comparison between the use of small equipment And large in the aspect of equipment demand. The study was developed from a hypothetical mining company based on realistic data. The developed model is applicable to any type of excavation and transportation equipment, regardless of its size and production capacity. In conclusion, it is intended with this dissertation to provide a useful tool to support the decision on sizing equipment and excavation and transport fleets capable of supplying the need for a market consultation.
4

Desenvolvimento de um modelo de dimensionamento de equipamento de escavacao e de transporte em mineração

Racia, Ismael Momade January 2016 (has links)
O motivo da dissertação “Desenvolvimento de um Modelo de Dimensionamento de Equipamentos de Escavação e de Transporte” surgiu da necessidade de apoiar no processo de decisão de dimensionamento dos principais equipamentos de mineração. Este trabalho apresenta um modelo simples e direto para dimensionar os equipamentos principais de mineração (escavadeiras e caminhões) através de uma rotina criada denominada EXCEsimulator, concebido para o cálculo da capacidade das caçambas das escavadeiras, do número dos equipamentos de escavação e de transporte, bem como os tempos de espera das unidades de transporte em carregar. Para tal, definem-se os parâmetros de produtividade e caraterísticas dos equipamentos; calcula-se aplicando um modelo determinístico de produção; e faz-se o levantamento de equipamentos existentes no mercado, reunindo as suas características e serviços prestados pelos representantes ou fabricantes das marcas. Para demostrar a funcionalidade do modelo desenvolvido, o presente trabalho demonstrou, através de um estudo de caso, o dimensionamento de uma frota de carregamento e transporte para uma mineração a céu aberto utilizando indicadores de produção, e uma comparação entre o uso de equipamentos de pequeno e grande porte no aspeto da demanda de equipamento. O estudo foi desenvolvido a partir de uma empresa de mineração hipotética baseada em dados realista. O modelo desenvolvido é aplicável a qualquer tipo de equipamento de escavação e de transporte, independente do seu porte e capacidade de produção. Como conclusão, pretende-se com esta dissertação fornecer uma ferramenta útil para o apoio à decisão de dimensionamento de equipamentos e frotas de escavação e de transporte capaz de suprir a necessidade de uma consulta de mercado. / The reason for the dissertation "Development of an Estimating Model for Excavation and Transport Equipment" arose from the need to support the decision-making process for the size of the main mining equipment. This work presents a simple and direct model for sizing the main mining equipment (excavators and trucks) through a routine created called EXCEsimulator, designed to calculate the capacity of excavator buckets, number of excavation and transport equipment, and As the waiting times of the transport units on loading. For this, the parameters of productivity and characteristics of the equipment are defined; Is calculated by applying a deterministic model of production; And it is made the survey of existing equipment in the market, gathering its characteristics and services provided by the representatives or manufacturers of the brands. To demonstrate the functionality of the developed model, the present study demonstrated, through a case study, the design of a loading and transport fleet for open pit mining using production indicators, and a comparison between the use of small equipment And large in the aspect of equipment demand. The study was developed from a hypothetical mining company based on realistic data. The developed model is applicable to any type of excavation and transportation equipment, regardless of its size and production capacity. In conclusion, it is intended with this dissertation to provide a useful tool to support the decision on sizing equipment and excavation and transport fleets capable of supplying the need for a market consultation.
5

Desenvolvimento de um modelo de dimensionamento de equipamento de escavacao e de transporte em mineração

Racia, Ismael Momade January 2016 (has links)
O motivo da dissertação “Desenvolvimento de um Modelo de Dimensionamento de Equipamentos de Escavação e de Transporte” surgiu da necessidade de apoiar no processo de decisão de dimensionamento dos principais equipamentos de mineração. Este trabalho apresenta um modelo simples e direto para dimensionar os equipamentos principais de mineração (escavadeiras e caminhões) através de uma rotina criada denominada EXCEsimulator, concebido para o cálculo da capacidade das caçambas das escavadeiras, do número dos equipamentos de escavação e de transporte, bem como os tempos de espera das unidades de transporte em carregar. Para tal, definem-se os parâmetros de produtividade e caraterísticas dos equipamentos; calcula-se aplicando um modelo determinístico de produção; e faz-se o levantamento de equipamentos existentes no mercado, reunindo as suas características e serviços prestados pelos representantes ou fabricantes das marcas. Para demostrar a funcionalidade do modelo desenvolvido, o presente trabalho demonstrou, através de um estudo de caso, o dimensionamento de uma frota de carregamento e transporte para uma mineração a céu aberto utilizando indicadores de produção, e uma comparação entre o uso de equipamentos de pequeno e grande porte no aspeto da demanda de equipamento. O estudo foi desenvolvido a partir de uma empresa de mineração hipotética baseada em dados realista. O modelo desenvolvido é aplicável a qualquer tipo de equipamento de escavação e de transporte, independente do seu porte e capacidade de produção. Como conclusão, pretende-se com esta dissertação fornecer uma ferramenta útil para o apoio à decisão de dimensionamento de equipamentos e frotas de escavação e de transporte capaz de suprir a necessidade de uma consulta de mercado. / The reason for the dissertation "Development of an Estimating Model for Excavation and Transport Equipment" arose from the need to support the decision-making process for the size of the main mining equipment. This work presents a simple and direct model for sizing the main mining equipment (excavators and trucks) through a routine created called EXCEsimulator, designed to calculate the capacity of excavator buckets, number of excavation and transport equipment, and As the waiting times of the transport units on loading. For this, the parameters of productivity and characteristics of the equipment are defined; Is calculated by applying a deterministic model of production; And it is made the survey of existing equipment in the market, gathering its characteristics and services provided by the representatives or manufacturers of the brands. To demonstrate the functionality of the developed model, the present study demonstrated, through a case study, the design of a loading and transport fleet for open pit mining using production indicators, and a comparison between the use of small equipment And large in the aspect of equipment demand. The study was developed from a hypothetical mining company based on realistic data. The developed model is applicable to any type of excavation and transportation equipment, regardless of its size and production capacity. In conclusion, it is intended with this dissertation to provide a useful tool to support the decision on sizing equipment and excavation and transport fleets capable of supplying the need for a market consultation.
6

The fungal communities associated with Red-cockaded Woodpeckers and their excavations: descriptive and experimental evidence of symbiosis

Jusino, Michelle Alice 29 July 2014 (has links)
Cavity-excavating birds, such as woodpeckers, are ecosystem engineers and are often assumed to rely upon wood decay fungi to assist in softening the wood of potential excavation sites. Endangered red-cockaded woodpeckers (Picoides borealis; RCWs) are the only birds known to solely excavate through the sapwood and into the heartwood of living pine trees and generally take many years to complete their excavations. These birds may have developed a partnership with wood-inhabiting fungi to facilitate the excavation process. Past attempts to understand the complex relationships between cavity excavators and fungi relied on visual surveys of fruiting bodies, or evidence of decay, resulting in a one bird, one fungus paradigm. Using molecular methods, I investigated the relationships between RCWs and fungi, and found that the relationships between cavity-excavators and fungi involve multiple fungal species and are far more complex than previously imagined. Through a field survey, I showed that RCW excavations contain distinct communities of fungi, and propose two hypotheses to explain this result, (1) RCWs select trees with distinct fungal communities (tree selection hypothesis), or (2) RCWs promote distinct fungal communities via their excavations (bird facilitation hypothesis). By swabbing the birds, I found that RCWs carry fungal communities similar to those found in their completed excavations, demonstrating that RCWs may directly facilitate fungal dispersal during the excavation process. Through a test of the bird introduction hypothesis which implemented human-made experimental drilled cavity starts (incomplete excavations), half of which were inaccessible to the birds, I showed that RCW accessibility influences fungal community development in excavations. This experimental evidence demonstrates that the relationship between RCWs and fungal communities is a multipartite symbiosis may be mutualistic. Finally, by tracking fungal community development in experimental cavity starts through time, I also demonstrated that the fungal communities found in RCW excavations undergo succession, and that this process is influenced by the birds. The relationships described in this body of work provide the basis for future studies on cavity excavators and fungi, and also have implications for a diverse community of secondary cavity nesters, wood-inhabiting fungi, forest ecology, and the conservation of biodiversity. / Ph. D.

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