• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2
  • 1
  • 1
  • Tagged with
  • 4
  • 4
  • 4
  • 4
  • 4
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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

Economic model of mine closure and its potential for economic transformation

Toni, 07 April 2015 (has links) (PDF)
In Indonesia, the various mining commodities and the amount of resources and reserves are promising, as evidence there are numerous large-scale mining companies and small-scale mines in operation. In 2014 there were 41 companies that held the CoW (mineral contract of work) and 13 companies active in production; and 76 CCoW (coal contract of work) holders, and 57 companies active in production. As well as this, there are more than a thousand small-scale mining companies active for mining commodities. However, mining commodities provide a resource that is not renewable. This will potentially lead to prolonged problems when mining companies do not adhere to good mining practices, particularly in the closing stages of the mine. Mine closure is the final stage in the process of mining activity. In certain circumstances, closure activities can take a long time and of course can have huge costs. In fact, at this stage, the company is no longer making profit, only incurring costs for the project closure. To prevent problems that may arise after the mine is closed, such as abandoned post-mining land, and the bankruptcy of the company at the end of mining operations, etc., then through specific rules, ie rules of the Minister of Energy and Mineral Resources No. 18 of 2008, the mining company in Indonesia must provide a certain amount of money as a financial guarantee to finance the planned closure project; it must be approved by the government before entering this phase. However, problems are encountered in practice. The government may become overloaded because they have to quickly make a decision on the closure plan submitted by the company. So a tool is needed that can be used to assess the feasibility as soon as the mine closure plan is proposed by a company, these tools can provide an overview and a variety of options for decision making. In this dissertation methodology was developed to create a systems dynamic model of mine closure. The model developed can be applied to a variety of mining methods and for various mining commodities. The model can be used to determine the closure costs, to choose the closure project-financing scenario, and up to micro and macro economic analysis of mining activities in the region. In the case studies conducted in this dissertation, the best scenario of the mine closure planning is to include the everlasting fund in the form of time deposits, and convert the post-mining land for agriculture. The amount of deposit money is about USD 358,986,500 should be spare at the end of mine production, and the total of mine closure cost to be approximately USD 440,757,384. Agriculture, the economic sector as a substitute for the mining sector, the added value to the GRDP (Gross Regional Domestic Product) is about 0.25 % / a for the province, and 1.68 % for the regency, but the contribution of the mining sector to GRDP was 30% / a at province scale, and 90% / a at regency scale. So that the substitution value is less significant to GRDP growth. However, this scenario is the best scenario among others, due to consideration is the certainty of ecological and economic sustainability. it is the best goal of corporate social responsibility to the environment in the post- mining land.
2

Modellbasierte Entwicklung von Energiemanagement-Methoden für Flugzeug-Energiesysteme

Schlabe, Daniel 26 January 2017 (has links) (PDF)
Ein geringer Treibstoffverbrauch ist aufgrund von ökologischen und ökonomischen Zielen für die zivile Luftfahrt von großer Bedeutung. Daher werden seit Jahrzehnten konventionell hydraulisch oder pneumatisch betriebene Flugzeugsysteme durch elektrisch betriebene Systeme ersetzt. Dieser Trend wird auch als „More Electric Aircraft (MEA)“ bezeichnet. In bisherigen Studien waren MEA-Architekturen zwar effizienter, jedoch deutlich schwerer als die konventionellen Architekturen. Basierend auf ökonomischen Modellen wird in der vorliegenden Arbeit die modellbasierte Entwicklung eines intelligenten Energiemanagements für Flugzeug-Energiesysteme demonstriert. Das Energiemanagement ermöglicht eine deutliche Reduktion der Systemmasse, verbessert die Energieeffizienz und kann damit den Treibstoffverbrauch eines MEA beträchtlich reduzieren. Insbesondere durch die integrierte und frühzeitige Entwicklung des Energiemanagements mit dem elektrischen System in der Modellbeschreibungssprache Modelica lassen sich die Systemkomponenten mit realistischen Lastprofilen dimensionieren und dadurch die Systemmasse reduzieren. Anhand eines elektrischen Referenzsystems wird das Optimierungspotenzial des Energiemanagements bezüglich Massenreduktion und Energieeffizienzsteigerung quantifiziert und am Systemmodell validiert. Es ergibt sich für das Systemmodell eine Reduktion der Systemmasse um 32 % sowie eine leichte Verbesserung der Energieeffizienz. Durch die multiphysikalische Implementierung des Energiemanagements lässt sich dieses auch für das thermische Management im Flugzeug verwenden. Hierbei kann eine deutliche Verbesserung der Energieeffizienz für die Bereitstellung von Kühlleistung erzielt werden. Aufgrund der erreichten Vorteile sollte ein Energiemanagement bei der Entwicklung zukünftiger Flugzeugenergiesysteme in Betracht gezogen werden. Insbesondere beim MEA existiert ein großes Optimierungspotenzial durch das Energiemanagement. Die Ausführungen in der vorliegenden Arbeit sollen als Motivation für die Flugzeugindustrie dienen, mit realistischen Lastprofilen zu dimensionieren und die modellbasierte und integrierte Entwicklung eines Energiemanagements mit den Energiesystemen bereits in frühen Entwicklungsphasen durchzuführen. / Low fuel consumption is a major concern in civil aerospace due to environmental and economic objectives. Hence, conventional hydraulically or pneumatically driven aircraft systems have been replaced by electrically driven systems for decades. This trend is also known as More Electric Aircraft (MEA). In former studies, MEA architectures were more efficient, but much heavier than their conventional counterparts. The present work demonstrates the model-based development of intelligent energy management algorithms for aircraft energy systems based on economic models. This energy management facilitates a significant reduction of system mass, improves energy efficiency and can hence reduce fuel consumption of MEA considerably. In particular, the integrated development of an energy management along with the electrical system in the Modelica modelling language enables sizing of system components with realistic load profiles. Hence, this reduces the system mass. The optimization potential of the energy management is quantified and validated by means of an electrical reference system model. Applying the energy management, the mass of this system model can be reduced by 32 % and the energy efficiency can be improved slightly. Due to the multi-physical modelling of the energy management, it can also be applied to thermal management of aircraft systems. Thus, the energy efficiency of the cooling system can be improved significantly. As a result of the demonstrated benefits, an energy management should be considered for future development of aircraft energy systems. Especially for MEA, there is tremendous optimization potential for the energy management. Hence, the present work shall motivate aircraft industry to size aircraft systems with realistic load profiles and perform a model-based and integrated development of the energy management along with the electrical system in early phases of the system design process.
3

Modellbasierte Entwicklung von Energiemanagement-Methoden für Flugzeug-Energiesysteme

Schlabe, Daniel 01 October 2015 (has links)
Ein geringer Treibstoffverbrauch ist aufgrund von ökologischen und ökonomischen Zielen für die zivile Luftfahrt von großer Bedeutung. Daher werden seit Jahrzehnten konventionell hydraulisch oder pneumatisch betriebene Flugzeugsysteme durch elektrisch betriebene Systeme ersetzt. Dieser Trend wird auch als „More Electric Aircraft (MEA)“ bezeichnet. In bisherigen Studien waren MEA-Architekturen zwar effizienter, jedoch deutlich schwerer als die konventionellen Architekturen. Basierend auf ökonomischen Modellen wird in der vorliegenden Arbeit die modellbasierte Entwicklung eines intelligenten Energiemanagements für Flugzeug-Energiesysteme demonstriert. Das Energiemanagement ermöglicht eine deutliche Reduktion der Systemmasse, verbessert die Energieeffizienz und kann damit den Treibstoffverbrauch eines MEA beträchtlich reduzieren. Insbesondere durch die integrierte und frühzeitige Entwicklung des Energiemanagements mit dem elektrischen System in der Modellbeschreibungssprache Modelica lassen sich die Systemkomponenten mit realistischen Lastprofilen dimensionieren und dadurch die Systemmasse reduzieren. Anhand eines elektrischen Referenzsystems wird das Optimierungspotenzial des Energiemanagements bezüglich Massenreduktion und Energieeffizienzsteigerung quantifiziert und am Systemmodell validiert. Es ergibt sich für das Systemmodell eine Reduktion der Systemmasse um 32 % sowie eine leichte Verbesserung der Energieeffizienz. Durch die multiphysikalische Implementierung des Energiemanagements lässt sich dieses auch für das thermische Management im Flugzeug verwenden. Hierbei kann eine deutliche Verbesserung der Energieeffizienz für die Bereitstellung von Kühlleistung erzielt werden. Aufgrund der erreichten Vorteile sollte ein Energiemanagement bei der Entwicklung zukünftiger Flugzeugenergiesysteme in Betracht gezogen werden. Insbesondere beim MEA existiert ein großes Optimierungspotenzial durch das Energiemanagement. Die Ausführungen in der vorliegenden Arbeit sollen als Motivation für die Flugzeugindustrie dienen, mit realistischen Lastprofilen zu dimensionieren und die modellbasierte und integrierte Entwicklung eines Energiemanagements mit den Energiesystemen bereits in frühen Entwicklungsphasen durchzuführen. / Low fuel consumption is a major concern in civil aerospace due to environmental and economic objectives. Hence, conventional hydraulically or pneumatically driven aircraft systems have been replaced by electrically driven systems for decades. This trend is also known as More Electric Aircraft (MEA). In former studies, MEA architectures were more efficient, but much heavier than their conventional counterparts. The present work demonstrates the model-based development of intelligent energy management algorithms for aircraft energy systems based on economic models. This energy management facilitates a significant reduction of system mass, improves energy efficiency and can hence reduce fuel consumption of MEA considerably. In particular, the integrated development of an energy management along with the electrical system in the Modelica modelling language enables sizing of system components with realistic load profiles. Hence, this reduces the system mass. The optimization potential of the energy management is quantified and validated by means of an electrical reference system model. Applying the energy management, the mass of this system model can be reduced by 32 % and the energy efficiency can be improved slightly. Due to the multi-physical modelling of the energy management, it can also be applied to thermal management of aircraft systems. Thus, the energy efficiency of the cooling system can be improved significantly. As a result of the demonstrated benefits, an energy management should be considered for future development of aircraft energy systems. Especially for MEA, there is tremendous optimization potential for the energy management. Hence, the present work shall motivate aircraft industry to size aircraft systems with realistic load profiles and perform a model-based and integrated development of the energy management along with the electrical system in early phases of the system design process.
4

Economic model of mine closure and its potential for economic transformation

Toni 07 April 2015 (has links)
In Indonesia, the various mining commodities and the amount of resources and reserves are promising, as evidence there are numerous large-scale mining companies and small-scale mines in operation. In 2014 there were 41 companies that held the CoW (mineral contract of work) and 13 companies active in production; and 76 CCoW (coal contract of work) holders, and 57 companies active in production. As well as this, there are more than a thousand small-scale mining companies active for mining commodities. However, mining commodities provide a resource that is not renewable. This will potentially lead to prolonged problems when mining companies do not adhere to good mining practices, particularly in the closing stages of the mine. Mine closure is the final stage in the process of mining activity. In certain circumstances, closure activities can take a long time and of course can have huge costs. In fact, at this stage, the company is no longer making profit, only incurring costs for the project closure. To prevent problems that may arise after the mine is closed, such as abandoned post-mining land, and the bankruptcy of the company at the end of mining operations, etc., then through specific rules, ie rules of the Minister of Energy and Mineral Resources No. 18 of 2008, the mining company in Indonesia must provide a certain amount of money as a financial guarantee to finance the planned closure project; it must be approved by the government before entering this phase. However, problems are encountered in practice. The government may become overloaded because they have to quickly make a decision on the closure plan submitted by the company. So a tool is needed that can be used to assess the feasibility as soon as the mine closure plan is proposed by a company, these tools can provide an overview and a variety of options for decision making. In this dissertation methodology was developed to create a systems dynamic model of mine closure. The model developed can be applied to a variety of mining methods and for various mining commodities. The model can be used to determine the closure costs, to choose the closure project-financing scenario, and up to micro and macro economic analysis of mining activities in the region. In the case studies conducted in this dissertation, the best scenario of the mine closure planning is to include the everlasting fund in the form of time deposits, and convert the post-mining land for agriculture. The amount of deposit money is about USD 358,986,500 should be spare at the end of mine production, and the total of mine closure cost to be approximately USD 440,757,384. Agriculture, the economic sector as a substitute for the mining sector, the added value to the GRDP (Gross Regional Domestic Product) is about 0.25 % / a for the province, and 1.68 % for the regency, but the contribution of the mining sector to GRDP was 30% / a at province scale, and 90% / a at regency scale. So that the substitution value is less significant to GRDP growth. However, this scenario is the best scenario among others, due to consideration is the certainty of ecological and economic sustainability. it is the best goal of corporate social responsibility to the environment in the post- mining land.

Page generated in 0.0554 seconds