Iskanje po katalogu digitalne knjižnice

Opis: We tested the hypothesis of procyclicality for economic activity and the stock exchanges of southeastern European countries relative to the main world Stock Exchange Centers, with a particular emphasis on Croatia (as a country preparing for EU accession) in order to demonstrate the dependence of small financial markets on large ones and to investigate the spillover effect, i.e., the degree and pace of integration of 'new' financial markets into larger ones. Our estimates for the southeastern countries individually and together support the hypothesis of an increase in stock exchange indices in the period of transition, due to the opening of the market economy followed by large capital inflows. Our results for Croatia provided us with evidence that EU accession is a trigger for the better financial integration of a candidate country. The observed countries that are already in the EU wing (Bulgaria, Romania and Slovenia) or those in the process of joining (Croatia and Montenegro) were found to be more dependent on the global financial markets and more exposed to adverse co-movements than other transitional southeastern countries (e.g. Bosnia and Herzegovina and Serbia).
Ključne besede: Stock Exchange, South-East Europe, financial integration, EU accession
Objavljeno: 17.02.2012; Ogledov: 2195; Prenosov: 107
Celotno besedilo (2,61 MB)

Opis: The essence of effective process designing is to use methods which are efficient to engineers in practice and not only to scientists. The proposed design procedure is composed of two steps: conceptual one and optimization one. At the conceptual step, pinch design analysis is used. In the optimization step pinch analysis and mixed-integer nonlinear programming method are applied. In the case study analysed, a speciality product is to beproduced in continuous chemical process with a capacity which causes smallerheat flow rates and needs smaller heat exchanger areas than usual. Therefore, an equation for cost estimation of heat exchangers with areas smaller than 7 m2 was developed and used in the optimization procedure. Using thermodynamic pinch analysis and mathematical programming method, the heat integrated structures were synthesized and compared with the base process flowsheet. Finally, the optimal structure was determined.
Ključne besede: načrtovanje procesov, načrtovanje procesov, ekonomska analiza, prenos toplote, optimizacija, chemical process design, economic analysis, heat integration, optimization
Objavljeno: 30.05.2012; Ogledov: 1631; Prenosov: 48
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Opis: Fuel-cell efficiencies yield substantial reductions in the emissions of climate-change gases and promise an end to exclusive reliance on carbon fuels for energy. Fuel cells, CO2 reuse, process heat integration, and open gas turbine electricity cogeneration can be optimized simultaneously, using a nonlinear programming (NLP) algorithm. The simplified NLP model contains equations of structural and parametric optimization. This NLP model is used tooptimize complex and energy-intensive continuous processes. This procedure does not guarantee a global cost optimum, but it does lead to good, perhaps near-optimum, designs. The plant, which produces methanol, has a surplus of hydrogen (H2) and CO2 flow rates in purge gas. H2 is separated from the purge gas by an existing pressure swing adsorption (PSA) column. Pure H2 can be usedas fuel in fuel cells. CO2 can be separated from the outlet stream (purge gas) by a membrane or absorption system (absorber and regenerator) or an adsorption system and reused as a reactant in a reactor system. Therefore, theproduct yield can be increased and CO2 emissions can be reduced, simultaneously. CO2 emissions can then be reduced at the source. The retrofitted process can be operated within existing parameters. Using a methanol process as a case study, the CO2 emission flow rate can be reduced by4800 t/a. The additional electricity cogeneration in the gas turbine and in fuel cells and additional flow rates of the raw material could generate an additional profit of 2.54 MEUR/a.
Ključne besede: chemical processing, methanol production, optimization, nonlinear programming, CO2 reuse, fuel cells, heat integration, energy cogeneration
Objavljeno: 31.05.2012; Ogledov: 1738; Prenosov: 57
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Opis: This paper provides an overview of software tools based on long experience andapplications in the area of process integration, modelling and optimisation. The first part reviews the current design practice and the development of supporting software tools. Those are categorised as: (1) process integration and retrofit analysis tools, (2) general mathematical modelling suites with optimisation libraries, (3) flowsheeting simulation and (4) graph-based process optimisation tools. The second part covers an assessment of tools which enable the generation of new sustainable alternatives to adapt to the future needs. They deal with waste, environment, energy consumption, resources depletion and production cost constrains. The emphasis of the sustainable process design tools is largely on the evaluation of process viability under sustainable economic conditions, synthesis of sustainable process and supply chain process maintenance and life cycle analysis. Major software tools development and the potential of the research-based tools for sustainable process design task are overviewed in theconcluding part.
Ključne besede: software tools, process integration, process modelling, process optimisation, energy saving
Objavljeno: 01.06.2012; Ogledov: 1357; Prenosov: 82
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Ključne besede: information systems, integration, EAI, CORBA, web services, J2EE, integrated systems
Objavljeno: 01.06.2012; Ogledov: 1845; Prenosov: 23
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