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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.
41

Evaluation of Capital Investment and Cash Flows for Alternative Switchgrass Feedstock Supply Chain Configurations

Chen, Jie 01 August 2011 (has links)
Biofuels have been widely recognized as a potential renewable energy source, and the United States’ government has been interested in producing ethanol from lignocellulosic biomass such as switchgrass. To evaluate whether lignocellulosic biomass based biofuels production is economically feasible, this paper estimated the capital investment outlays, operation costs, and net present value for investment in alternative switchgrass feedstock supply chain configurations in East Tennessee a 25 million gallon per year ethanol biorefinery. Two scenarios are analyzed in the study. The conventional hay harvest scenario includes the production, harvest, storage and transportation of biomass feedstocks from the fields to the biorefinery. The preprocessing scenario added preprocessing facilities into the biomass supply chain. According to various harvest, storage, preprocessing, and harvest equipment options, analysis and comparisons were made among different systems. The capital budgeting model developed in this study generated the optimal feedstock supply chain configurations to determine the largest net present value of cash flow from investment. Results of this study shown that with the Biomass Crop Assistance Program (BCAP) incentives, a round bale system using feedstock stored without tarp on pallets using custom hired equipment had the largest positive net present value. By comparison, if all the harvest equipment is purchased rather than custom hired, the stretch wrap baler preprocessing systems, using switchgrass harvested by a chopper with rotary cutter-header, was found to have a cost advantage over conventional hay harvest logistic systems (large round bale and large square bale systems) and pellet preprocessing systems. Assuming most likely values for switchgrass price and production costs, none of the feed stock supply chain configurations evaluated in this study produced a positive net present value when BCAP subsidies were assumed to not be available. However, without the BCAP incentives and based on combination of optimistic assumption, the round bale system using feedstock stored without tarp on pallets using custom hired equipment still has the largest positive net present value. Without the BCAP incentives, no feedstock supply chain configuration using purchased rather than custom hired equipment generated a positive net present value.
42

Bioeconomic analysis of northwest pacific Ommastrephes bartrami

Lui, Shu-Hai 21 June 2010 (has links)
In this research, using the statistic catch data of northwest pacific Ommastrephes bartrami from the Overseas Fisheries Development council of The Republic of China between 1997 to 2007 and FAO between 1982 to 2007 to conduct and resource assessment on Ommastrephes bartrami. First of all, calculate and compare the equilibrium levels of open access fishery and present value maximization fishery, then evaluate the stock size of Ommastrephes bartrami and compare the equilibrium levels of two models with the statistic readings, the result shows the Ommastrephes bartrami has no sign of depletion. By using sensitivity analysis, we understand the changes on the effort and stock effected by varying different parameters. Finally, by simulating the stock size of open access fishery and present value maximization fishery, we find that unrestricted developing can end up the resources, but Ommastrephes bartrami will receive sustainable development, if it can be effectively managed. And expect that the results can be a management reference for the management of Ommastrephes bartrami fisheries.
43

Simulation and Economic Analysis of a Hybrid Wind Diesel System for Remote Area Power Supply

Abdullah, Jalal 06 September 2010 (has links)
The Kingdom of Saudi Arabia has an area of 1.69 million square kilometers. It is the biggest oil producers in the world, and the electricity industry relies heavily on oil. The annually growth request for electricity is around 5%. The price of electricity will be expensive in the next 30 years and there could be a shortage of electricity supply. It is better to use alternative forms of energy to prolong the life of the oil industry in Saudi Arabia. To reduce dependence on oil, the Kingdom of Saudi Arabia is considering using alternative sources of energy including solar energy and energy wind. Since the wind speed is around 10m/s and in the summer it is full of sunshine; therefore, the renewable energy should play a more important role in future electric power supply of the Kingdom of Saudi Arabia. A hybrid system is proposed in this thesis to study the possible power supply system in the remote areas. Wind information in Dhahran is used in simulations in order to make sure that the system is reliable and appropriate to be used in the remote areas of the country. Economic analysis is also conducted to compare the cost of the hybrid system with that of a 200 km transmission line connected from existing service area.
44

Estimation of Thunnus alalunga stock and economic analysis in the Western and Central Pacific Fishery

Luo, Lan-shin 11 July 2011 (has links)
The study is based on Gordon-Schaefer model, using statistic data from Western and Central Pacific Fishery Commission to estimate the resource stock of Albacore between 1960 and 2009. Compare the equilibrium levels of open access model and present value maximization model with the real data, and the result shows that the real stock is close to the equilibrium of present value maximization model. The thesis uses sensitivity analysis to understand the impact of the changed parameters on stock and effort, and by using real examples to understand the impact of the changed situation on stock and effort. Finally, by simulating the stock of open access fishery and present value maximization fishery and government management nowadays fishery. The result shows the stock of government management fishery is higher than the stock of the present value maximization fishery, and the stock both are closed. The management is conservative and effective, hence the management will make the profit maximize and the resource continue forever to develop.
45

The stock assessment Analysis of the Thunnus obesus in the Western and Central Pacific Ocean

Liu, Yu-li 16 February 2012 (has links)
This study used the Gordon-Schaefer model to discuss the equilibrium levels for bigeye tuna in the Western and Central Pacific of open access and present value maximization. And then to compare the catches and the stocks on the two model¡¦s equilibrium value, the result shows the management of bigeye tuna in the Western and Central Pacific tend to present value maximization model. Following that, this paper did sensitivity analysis to understand the impact of the changed parameters on stock size and effort. Finally, using simulation analysis on open access model and present value maximization model. In open access model, the result shows that resources will face extinction crisis if the fishery is not controlled well. In the present value maximization model, the bigeye tuna would be sustainable management. This result is valuable for the fishery management authorities to maintain the development of fishery and cherishing ocean resources at the same time.
46

The Bioeconomic Analysis of Bigeye Tuna (Thunnus obesus) in the Western and Central Pacific Ocean

Chang, Yu-ching 19 June 2012 (has links)
This study used the Gordon-Schaefer model which was extended to Open Access (OA) model and Present Value Maximization (MPV) model to discuss the equilibrium levels for bigeye tuna in the Western and Central Pacific Ocean by purse seine fishery data. I compared the catches and the biomass with the two model¡¦s equilibrium value, and the result showed that the operating mode of bigeye tuna in the Western and Central Pacific Ocean tended to the MPV model, and the bigeye tuna resources were diminishing. In addition, the sensitivity analysis was used in order to understand the impact of various parameter changes on the two fisheries model¡¦s equilibrium value. In the OA model, the change of the price, the cost per unit effort and the catch coefficient would have greater impact on the equilibrium biomass. In the MPV model, the equilibrium biomass was sensitive to the change of the environmental capacity. Finally, in order to understand whether the management of the Western and Central Pacific Commission (WCPFC) was effective, I used simulation analysis in accordance with the catches restriction and effort restriction management strategies. The result showed that the catches restriction strategy which WCPFC established was still not proper enough. It must cut a large number of catches immediately and continue for some time enough to make the resource recover. The effort restriction strategy could make good effect on the bigeye tuna resource recovery.
47

Discrete Event Model Development of Pilot Plant Scale Microalgae Facilities: An Analysis of Productivity and Costs

Stepp, Justin Wayne 2011 August 1900 (has links)
America's reliance on foreign oil has raised economic and national security issues, and in turn the U.S. has been active in reducing its dependence on foreign oil to mitigate these issues. Also, the U.S. Navy has been instrumental in driving bio-fuel research and production by setting an ambitious goal to purchase 336M gallons of bio-fuel by 2020. The production of microalgae biomass is a promising field which may be able to meet these demands. The utilization of microalgae for the production of bio-fuel requires the implementation of efficient culturing processes to maximize production and reduce costs. Therefore, three discrete rate event simulation models were developed to analyze different scaling scenarios and determine total costs associated with each scenario. Three scaling scenarios were identified by this analysis and included a stepwise, volume batching and intense culturing process. A base case and potential best case were considered in which the culturing duration, lipid content and lipid induction period were adjusted. A what-if analysis was conducted which identified and reduced capital and operational costs contributing greatly to total costs. An NPV analysis was performed for each scenario to identify the risk associated with future cash flows. The research findings indicate that the intense culturing scaling scenario yielded the greatest model throughput and least total cost for both the base case and potential best case. However, this increased productivity and cost reduction were not significantly greater than the productivity generated by the stepwise scaling scenario, suggesting that the implementation of flat plate bio-reactors in the intense culturing process may be non-advantageous given the increased operational costs of these devices. The volume batching scenario yielded the greatest total cost L^-1 of microalgae bio-oil for both, indicating an inefficient process. The scaling scenarios of the base case and potential best case yielded negative NPV's while the stepwise and intense culturing scenarios of the what-if analysis generated positive NPV's. The base case is based on current technological advances, biological limitations and costs of microalgae production therefore, a negative NPV suggests that utilizing microalgae for bio-fuel production is not an economically feasible project at this time.
48

none

Li, Chin-Yu 02 August 2001 (has links)
none
49

The biological and economical analysis of the resource of South Pacific albacore

Chiu, szu-wei 14 June 2009 (has links)
Abstract This study used the Gordon-Schaefer model to do resource economic analysis on the South Pacific albacore fishery in 1967-2007 . Evaluated the equilibrium standard of open access model and present value maximization model, and then compared them with the real data. The results indicates that the fishing yield, resource stock, effort and catch-per-unit-effort of south Pacific albacore is close to the equilibrium level of present value maximization model after year 2002, which means the South Pacific albacore fishing is under appropriate development. Following that, this paper did sensitivity analysis to understand the impact of the changed parameters on stock size and effort. Finally, using the simulation analysis on open access model and present value maximization model. In open access model, the result shows that resources will face extinction crisis if the fishery is not controlled well. In present value maximization model, the albacore fishery would sustainable management. This result is valuable for the fishery management authorities to maintain the development of fishery and cherishing ocean resources at the same time.
50

Bioeconomic analysis of Argentine shortfin squid, Illex argentinus in the Southwest Atlantic.

Wang, Bi-yi 14 June 2009 (has links)
This research is based on Gordon-Schaefer model, using the statistic data from the FAO between 1983 to 2007 to conduct an assessment on Argentine shortfin squid, Illex argentinus. First of all, calculate and compare the equilibrium levels of open access fishery and present value maximization fishery, then evaluate the stock size of Illex argentinus and compare the equilibrium levels of two models with the statistic readings, the result shows that Illex argentinus has no sign of depletion, but it has not yet reached the best status for development. By using sensitivity analysis,we understand the changes on the effort and stock effected by varying different parameters. Finally, by simulating the stock size of open access fishery and present value maximization fishery, we find that unrestricted developing can end up the resources, but Illex argentinus will receive sustainable development, if it can be effectively managed.

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