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Condicionantes da viabilidade de produção do biodiesel a partir do dendê e do pinhão-manso no semi-árido brasileiro / Guidance to feasibility of biodiesel production after the palm and jatropha curcas in the brazilian semi-aridLima Júnior, José Carlos de 24 November 2008 (has links)
Diversos são os direcionadores para a atenção mundial na adoção dos biocombustíveis. Elevados preços do petróleo e aquecimento global figuram entre os principais. Sob esse cenário, vários países investem em pesquisas para encontrar uma fonte de energia limpa produzida em um contexto sustentável. Entre elas está o biodiesel obtido dos óleos vegetais. No Brasil, após a institucionalização da mistura em janeiro de 2008, destacouse a necessidade de realizar estudos aprofundados na seleção da melhor matéria-prima destinada à manutenção do programa brasileiro, além de estabelecer novas áreas de produção que atendam, simultaneamente, a inserção do pequeno agricultor e a produção equilibrada com os alimentos. A produtividade por hectare é identificada a priori como relevante, de modo que este estudo considerou as culturas do dendê e do pinhão-manso como matériasprimas, bases à viabilidade de produção do biodiesel no Brasil. O semi-árido brasileiro foi escolhido devido às grandes extensões de terra produtivas, mas inativas, e aos incentivos federais que proporcionam uma vantagem competitiva no Ambiente Institucional. A metodologia de pesquisa fez uso conjunto da Fenomenologia e dos Estudos de Caso, aplicando a análise na região do Vale do São Francisco. Para a condução da pesquisa foi utilizada a base de dados primários e secundários. O ambiente de pesquisa fez uso do ambiente de campo e do estudo simulado dos dados em planilhas eletrônicas. Os resultados obtidos destacaram o fator produtividade por área plantada e teor de óleo por peso da cultura como dois importantes condicionantes para a viabilidade de produção do biodiesel, além da integração das atividades agrícola e industrial. O estudo finaliza, comprovando a viabilidade de implantar um SAG do Biodiesel na região semi-árida brasileira, fazendo uso das áreas irrigadas e das áreas de sequeiro. / There is a wide guidance to the world\'s attention in the adoption of biofuels. High oil prices and global warming are among the main ones. Under this scenario, several countries have invested in research to find a source of clean energy produced in a sustainable context. Among them is biodiesel made from vegetable oils. In Brazil, after the institutionalization of the mixture in January 2008, the need to conduct studies in the selection of the best raw material for the maintenance of the Brazilian program was highlighted, in addition to establish new areas of production that meet both the insertion of small farmers and balanced production along with food. The yield per hectare is taken as relevant, so this study has taken in account the crops of palm and jatropha curcas as raw materials, considering the feasibility of producing biodiesel in Brazil. The Brazilian semi-arid was chosen because of the large area of productive, but inactive land and federal incentives that provide a competitive advantage in the Institutional Environment. The research methodology made use of all Phenomenology and Case Studies by applying the analysis in the Valley of San Francisco River. To conduct the research, a basis for primary and secondary data was used. The research environment made use of field environment and simulated study of data in spreadsheets. The results highlighted the factor productivity per planted area and oil content by weight of crop as two major constraints to the feasibility for biodiesel production, in addition to the integration of agricultural and industrial activities. The study ends, proving the feasibility of settling a Biodiesel SAG in the semiarid region in Brazil, using irrigated and dry areas.
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Förstudier av kommersiella fastigheter : En analys av arbetssätt ur ett projektledarperspektiv / Feasibility studies of commercial real estates : An analysis of the pre-project planning phase in Swedish construction companiesRashidi, Ehsan January 2009 (has links)
<p>This thesis is written at WSP management and investigates the practice of pre-project planning and feasibility studies at Swedish construction companies, through the study of the ongoing feasibility study of the mall Sturegallerian in Stockholm, and through interviews with experienced project managers in the construction industry. There is currently a big span in the way Swedish construction companies plan the pre-project phase and the aim of this thesis is to present a more generic and standardized way that helps minimize project risks and maximize efficiency and profit.</p><p> </p><p>The result is a generic model which can be used in pre-project planning. The model describes the phases in the preproject planning process and the activities that span these phases. Is also describes the categories of professions that need to participate in the preproject planning group and which activities that each profession executes.</p><p> </p><p>The other result is a list of factors that need to be considered for a well performed pre-project phase, as found during the interviews. Among others the thesis stresses the importance of involving the client as a key participant in the process. The importance of testing the profitability of the idea is also being discussed. The interviews also indicated that the pre-project phase is not linear but rather transactional and that the original alternatives presented to the client lead to new client desires and requirements.</p>
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Multi-period optimization of pavement management systemsYoo, Jaewook 30 September 2004 (has links)
The purpose of this research is to develop a model and solution methodology for selecting and scheduling timely and cost-effective maintenance, rehabilitation, and reconstruction activities (M & R) for each pavement section in a highway network and allocating the funding levels through a finite multi-period horizon within the constraints imposed by budget availability in each period, frequency availability of activities, and specified minimum pavement quality requirements. M & R is defined as a chronological sequence of reconstruction, rehabilitation, and major/minor maintenance, including a "do nothing" activity. A procedure is developed for selecting an M & R activity for each pavement section in each period of a specified extended planning horizon. Each activity in the sequence consumes a known amount of capital and generates a known amount of effectiveness measured in pavement quality. The effectiveness of an activity is the expected value of the overall gains in pavement quality rating due to the activity performed on a highway network over an analysis period. It is assumed that the unused portion of the budget for one period can be carried over to subsequent periods. Dynamic Programming (DP) and Branch-and-Bound (B-and-B) approaches are combined to produce a hybrid algorithm for solving the problem under consideratioin. The algorithm is essentially a DP approach in the sense that the problem is divided into smaller subproblems corresponding to each single period problem. However, the idea of fathoming partial solutions that could not lead to an optimal solution is incorporated within the algorithm to reduce storage and computational requirements in the DP frame using the B-and-B approach. The imbedded-state approach is used to reduce a multi-dimensional DP to a one-dimensional DP. For bounding at each stage, the problem is relaxed in a Lagrangean fashion so that it separates into longest-path network model subproblems. The values of the Lagrangean multipliers are found by a subgradient optimization method, while the Ford-Bellman network algorithm is employed at each iteration of the subgradient optimization procedure to solve the longest-path network problem as well as to obtain an improved lower and upper bound. If the gap between lower and upper bound is sufficiently small, then we may choose to accept the best known solutions as being sufficiently close to optimal and terminate the algorithm rather than continue to the final stage.
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Study into the Potential and Feasibility of a Standalone Solar-Wind Hybrid Electric Energy Supply SystemBekele, Getachew January 2009 (has links)
The tendency to use renewable energy resources has grown continuouslyover the past few decades, be it due to fear over warnings of globalwarming or because of the depletion and short life of fossil fuels or evenas a result of the interest which has developed among researchers doingscientific research into it. This work can be considered as joining any ofthese groups with an objective of giving electric light to the poorpopulation living in one of the poorest nations in the world.The aim of the work is to investigate supplying electric energy fromsolar-wind hybrid resources to remotely located communities detachedfrom the main grid line in Ethiopia. The communities in mind are one oftwo types; the first is the majority of the poor population residing in thecountryside; and the other is people relocated by the Government fromthe over used and dry regions to relatively productive and fertile ones inline with the long-term poverty reduction plan.The work was begun by investigating wind energy and solar energypotentials at four geographically different locations in Ethiopia bycompiling data from different sources and analyzing it using a softwaretool. The locations are Addis Ababa (09:02N, 038:42E), Mekele (13:33N,39:30E), Nazret (08:32N, 039:22E), and Debrezeit (8:44N, 39:02E).The results related to wind energy potential are given in terms of themonthly Average wind speed, the wind speed probability densityfunction (PDF), the wind speed cumulative density function (CDF), thewind speed duration curve (DC), and power density plots for all fourselected sites. According to the results obtained through the analysis, thewind energy potential, even if it is not exceptional, is irrefutably highenough to be exploited for generating electric energy.The solar energy potential, based on sunshine duration data collectedover a period of 7 - 11 years and radiation data obtained from differentsources, has been calculated using regression coefficients specific to thesites in question. Based on the sunshine duration data, the monthlyaverage daily sunshine amount for each of the places has also beencomputed and given in a form of plot. Through additional work on theresults of the calculations, the solar energy potential has been given inthe form of solar radiation plots for each of the selected sites. Asexpected, the results indicated an abundance of solar energy potential.It is based on the promising findings of these two energy resourcepotentials, wind and solar, that the feasibility study for a standalonesolar-wind hybrid energy supply system has proceeded, targeting thecommunity mentioned earlier. The hybrid system consisted of Windturbine, Photovoltaic panel, diesel generator and a bank of batteries, witha power conditioning converter included in the system.The hybrid standalone supply system is intended to provide electricity toa model community of 200 families with five to six family members ineach. The community is equipped with a primary load, a deferrable load,a community school and a health post. An electric load which includeslighting, water pumping, a radio receiver, and some clinical equipmenthas been suggested. Hybrid Optimization Model for ElectricRenewables, HOMER, software has been used for the analysis. Theaverage wind speed and average solar radiation calculated from the datafor all of the selected sites has been used to input into the software.The hybrid system design is approached in three different ways. The firstapproach is to include within the hybrid system those components whichare locally available, without giving special attention to their efficienciesand proceed with the design work. The second approach is tothoroughly search the market for the best and most efficienttechnological products and to select the best components for theanalysis. A third approach considered in an attempt of cost minimizationis to see if a self-contained type of design can be a better solution. Whatthis means is every household will have its own supply system that mayconsist of any combination of PV and wind turbine including converter,battery and charge controller.After running the simulations, lists of power supply systems have beengenerated, sorted according to their net present cost. Sensitivity variables,such as range of wind speeds, range of radiation levels and diesel pricehave been defined as inputs into the software and the optimizationprocess has been carried out repeatedly for the sensitivity variables andthe results have been refined accordingly. / QC 20100623
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Prospects for the reform of District Municipalities: the scope for manoeuvreJoseph, Abdul Wahid January 2012 (has links)
No description available.
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Prospects for the reform of district municipalities: the scope for manoeuvreJoseph, AW January 2010 (has links)
No description available.
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Förstudier av kommersiella fastigheter : En analys av arbetssätt ur ett projektledarperspektiv / Feasibility studies of commercial real estates : An analysis of the pre-project planning phase in Swedish construction companiesRashidi, Ehsan January 2009 (has links)
This thesis is written at WSP management and investigates the practice of pre-project planning and feasibility studies at Swedish construction companies, through the study of the ongoing feasibility study of the mall Sturegallerian in Stockholm, and through interviews with experienced project managers in the construction industry. There is currently a big span in the way Swedish construction companies plan the pre-project phase and the aim of this thesis is to present a more generic and standardized way that helps minimize project risks and maximize efficiency and profit. The result is a generic model which can be used in pre-project planning. The model describes the phases in the preproject planning process and the activities that span these phases. Is also describes the categories of professions that need to participate in the preproject planning group and which activities that each profession executes. The other result is a list of factors that need to be considered for a well performed pre-project phase, as found during the interviews. Among others the thesis stresses the importance of involving the client as a key participant in the process. The importance of testing the profitability of the idea is also being discussed. The interviews also indicated that the pre-project phase is not linear but rather transactional and that the original alternatives presented to the client lead to new client desires and requirements.
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Sensorless Speed Control of Permanent Magnet-Assisted Synchronous Reluctance Motor (PMa-SynRM)Chakali, Anil K. 2009 December 1900 (has links)
An interesting alternative for today's high efficiency variable speed drives is the Permanent Magnet-Assisted Synchronous Reluctance Motor drive, which belongs to the family of brushless synchronous AC motor drives. Generally, the reluctance torque of this motor is significant compared to the Permanent Magnet electrical torque. The advantage of increased reluctance torque is the decreased need of expensive permanent magnet (PM) material, which makes this solution thus cheaper than the respective permanent magnet motor. Also due to its synchronous operation, sensorless rotational control is possible along with higher power factor and better efficiency compared to the induction motor (IM).
Therefore, this thesis first deals with the implementation of a vector control strategy for speed control of the PMa-synRM motor that can be applied to a washing machine application. The machine is supplied by a current controlled voltage source PWM inverter to control the instantaneous stator currents which are decided by the reference speed.
Secondly, the thesis focuses on the sensorless speed operation of the PMa-SynRM to take advantage of the lower costs as well as increased system reliability which otherwise is not possible using the delicate speed or position sensors. The concept involves estimation of the rotor speed and/or position. There are several speed estimation techniques proposed by researchers and among them the observer based technique is proven and commonly used in the industry. The only requirements of the observer system are a very fast signal processor, specialized and optimized to perform complex mathematical calculations.
The feasibility and effectiveness of the control techniques are verified using the experimental results, implemented using the Texas Instruments TMS320F2812 eZDSP controller board and the overall motor drive system in the laboratory.
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Feasibilty Study Of Sequestration Of Carbon Dioxide In Geological FormationsGultekin, Cagdas 01 January 2011 (has links) (PDF)
Although there are some carbon capture and storage (CCS-CO2 sequestration) projects in all over the world, feasibility problems exist due to the high economical issues. The aim of this study is to evaluate the feasibility of a potential CCS project where the source of CO2 is Afsin Elbistan Thermal Power Plant. Selection of candidate sites in the vicinity of Diyarbakir, Batman and Adiyaman regions depends on sequestration criteria. According to sequestration criteria, CCS can be applied to Ç / aylarbasi mature oil field, Midyat saline aquifer and Dodan CO2 gas field. Disposing of CO2 from the source of Afsin Elbistan Thermal Power Plant is analyzed
by pipeline and tanker. CO2 capturing technologies are determined from published literature. CO2 transportation can be applied by pipeline or tanker. CO2 transportation cost by pipeline and tanker are compared. It has been calculated that, transportation by pipeline is more economical compared to tanker transportation. It is further found that the number of boosting pump stations, the length of the pipeline and CO2 mass flow rate are the issues that alter the economical aspect in the pipeline transportation. The transportation costs by tankers depend on fuel cost, distance, tanker storage capacity, pin-up cost and CO2 storage facilities. The final part of CCS project is injection and storage of CO2 to the candidate areas. Reservoir parameters which are reservoir temperature, viscosity, permeability, reservoir pressure, reservoir thickness, CO2 density mass flow rate and injection pipe diameter determine the number and cost of the injection wells.
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Iterative Approaches to the Split Feasibility ProblemChien, Yin-ting 23 June 2009 (has links)
In this paper we discuss iterative algorithms for solving the split feasibility
problem (SFP). We study the CQ algorithm from two approaches: one
is an optimization approach and the other is a fixed point approach. We
prove its convergence first as the gradient-projection algorithm and secondly
as a fixed point algorithm. We also study a relaxed CQ algorithm in the
case where the sets C and Q are level sets of convex functions. In such case
we present a convergence theorem and provide a different and much simpler
proof compared with that of Yang [7].
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