935 resultados para Statistics|Economics, Finance|Engineering, Electronics and Electrical|Physics, General
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The thesis is divided into four chapters. They are: introduction, experimental, results and discussion about the free ligands and results and discussion about the complexes. The First Chapter, the introductory chapter, is a general introduction to the study of solid state reactions. The Second Chapter is devoted to the materials and experimental methods that have been used for carrying out tile experiments. TIle Third Chapter is concerned with the characterisations of free ligands (Picolinic acid, nicotinic acid, and isonicotinic acid) by using elemental analysis, IR spectra, X-ray diffraction, and mass spectra. Additionally, the thermal behaviour of free ligands in air has been studied by means of thermogravimetry (TG), derivative thermogravimetry (DTG), and differential scanning calorimetry (DSC) measurements. The behaviour of thermal decomposition of the three free ligands was not identical Finally, a computer program has been used for kinetic evaluation of non-isothermal differential scanning calorimetry data according to a composite and single heating rate methods in comparison with the methods due to Ozawa and Kissinger methods. The most probable reaction mechanism for the free ligands was the Avrami-Erofeev equation (A) that described the solid-state nucleation-growth mechanism. The activation parameters of the decomposition reaction for free ligands were calculated and the results of different methods of data analysis were compared and discussed. The Fourth Chapter, the final chapter, deals with the preparation of cobalt, nickel, and copper with mono-pyridine carboxylic acids in aqueous solution. The prepared complexes have been characterised by analyses, IR spectra, X-ray diffraction, magnetic moments, and electronic spectra. The stoichiometry of these compounds was ML2x(H20), (where M = metal ion, L = organic ligand and x = water molecule). The environments of cobalt, nickel, and copper nicotinates and the environments of cobalt and nickel picolinates were octahedral, whereas the environment of copper picolinate [Cu(PA)2] was tetragonal. However, the environments of cobalt, nickel, and copper isonicotinates were polymeric octahedral structures. The morphological changes that occurred throughout the decomposition were followed by SEM observation. TG, DTG, and DSC measurements have studied the thermal behaviour of the prepared complexes in air. During the degradation processes of the hydrated complexes, the crystallisation water molecules were lost in one or two steps. This was also followed by loss of organic ligands and the metal oxides remained. Comparison between the DTG temperatures of the first and second steps of the dehydration suggested that the water of crystallisation was more strongly bonded with anion in Ni(II) complexes than in the complexes of Co(II) and Cu(II). The intermediate products of decomposition were not identified. The most probable reaction mechanism for the prepared complexes was also Avrami-Erofeev equation (A) characteristic of solid-state nucleation-growth mechanism. The tempemture dependence of conductivity using direct current was determined for cobalt, nickel, Cl.nd copper isonicotinates. An activation energy (ΔΕ), the activation energy (ΔΕ ) were calculated.The ternperature and frequency dependence of conductivity, the frequency dependence of dielectric constant, and the dielectric loss for nickel isonicotinate were determined by using altemating current. The value of s paralneter and the value of'density of state [N(Ef)] were calculated. Keyword Thermal decomposition, kinetic, electrical conduclion, pyridine rnono~ carboxylic acid, cOlnplex, transition metal compJex.
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A novel metathesis catalyst for the polymerisation of acetylene has been developed. The polyacetylene produced by this new catalyst has been characterised by infra-red and NMR spectroscopy. The conductivity of the pristine material has been studied as a function of temperature, pressure and frequency. The effect on the conductivity of doping the material has also been investigated. The new metathesis catalyst has been incorporated into an anionic-to-metathesis transformation reaction. This novel reaction has been used to prepare samples of poly(styrene-co-acetylene). The copolymer has been characterised using U.V./Visible, NMR, infra-red spectroscopy and the surface morphology looked at using scanning electron microscopy. GPC was also used to give some idea of the molecular weights of the materials prepared. The conductivity of the copolymer has been studied as a function of temperature, pressure and frequency. The effect of doping on the conductivity the material has also been investigated. The conductivity results obtained from both materials have been used to try and gain an insight into the mechanism of the conduction processes occurring within the materials. An attempt has also been made to synthesise polyacetylene oligomers (polyenes) by modifying the Ziegler/Natta type catalysts commonly used to synthesise polyacetylene. The polyenes were characterised using U.V./Visible and infra-red spectroscopy together with GPC and GCMS.
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Fully dense graphene nanosheet(GNS)/Al2O3 composites with homogeneously distributed GNSs of thicknesses ranging from 2.5 to 20 nm have been fabricated from ball milled expanded graphite and Al2O3 by spark plasma sintering. The percolation threshold of electrical conductivity of the as-prepared GNS/Al2O3 composites is around 3 vol.%, and this new composite outperforms most of carbon nanotube/Al2O3 composites in electrical conductivity. The temperature dependence of electrical conductivity indicated that the as-prepared composites behaved as a semimetal in a temperature range from 2 to 300 K.
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This book provides a comparative analysis of the emerging corporate control structures in the transition economies. It details characteristics of corporate governance in the two largest transition economies: Russia and Poland. It explores what kind of ownership structures are emerging in these two countries and to what degree they are they path-dependent and conditional on the initial choice of privatisation methods - fast ownership transfer through the mass privatisation programme and loans-for-equity scheme in Russia, and a more 'organic' growth of the new private sector in Poland. It examines the directions of the subsequent, post-privatisation, secondary ownership flows in both countries and the impact of the government on corporations, implied both by the residual shareholding of the state and by its regulatory and administrative actions.
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The accurate in silico identification of T-cell epitopes is a critical step in the development of peptide-based vaccines, reagents, and diagnostics. It has a direct impact on the success of subsequent experimental work. Epitopes arise as a consequence of complex proteolytic processing within the cell. Prior to being recognized by T cells, an epitope is presented on the cell surface as a complex with a major histocompatibility complex (MHC) protein. A prerequisite therefore for T-cell recognition is that an epitope is also a good MHC binder. Thus, T-cell epitope prediction overlaps strongly with the prediction of MHC binding. In the present study, we compare discriminant analysis and multiple linear regression as algorithmic engines for the definition of quantitative matrices for binding affinity prediction. We apply these methods to peptides which bind the well-studied human MHC allele HLA-A*0201. A matrix which results from combining results of the two methods proved powerfully predictive under cross-validation. The new matrix was also tested on an external set of 160 binders to HLA-A*0201; it was able to recognize 135 (84%) of them.
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Whether distance learning spells the end of traditional campuses, as some maintain, or whether distance learning instead represents a powerful addition to a growing array of delivery options for higher education, its impact on higher education is great and growing. Distance learning is creating alternative models of teaching and learning, new job descriptions for faculty, and new types of higher education providers. The advent of Distance and Distributed Learning has raised numerous questions about quality and quality assurance: ² How do established distance learning institutions ensure quality? ² What more needs to be done? ² How do quality assurance agencies view the distinction between on- and off-campus teaching and learning? This talk discusses these issues from the viewpoints of funding organisa- tion, quality assurance agencies and the learners.
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Purpose – This paper aims to investigate the manner in which technological innovation in the European electrical-grid sector has developed by focusing, in particular, on the effect of public policy on innovation. To achieve this aim, this paper highlights how technological innovation and development progressed from the 1960s to the 1980s, and contrasts this period with the deregulated/privatization environment. Design/methodology/approach – The paper is based on a series of in-depth multiple company case studies of grid companies, some of their suppliers and other actors in their broader business network. Empirical data were collected through 55 interviews. Findings – The authors find that a phase of mutual collaboration was encouraged in the first period, which led to strong technological innovation with a focus on product quality and the development of functionality. Buyers played a pivotal role in the development of products and posed technical requirements. In contrast, the current role of the buyer has transformed principally into one of evaluating competing bids for specific projects. Today, buyers face increasing pressure to substantially lower CO2 emissions and transform the energy grid system. These goals are difficult to achieve without a new way of thinking about innovation. Research limitations/implications – Models to achieve innovation must not only focus on individual research projects; instead, the innovation should be factored into normal business dealings in the supply chain. Practical implications – We propose that policymakers and regulators need to: accommodate for innovation and address the collaborative elements of innovation when developing policies and regulations. Furthermore, regulators have the option of either developing a strategic vision for the electrical-grid network or incorporating sustainability into the evaluation of electrical grids and, thus, consumers’ willingness to pay. Originality/value – This paper makes a distinctive contribution in the area of innovation for electrical grids. Our paper shows how innovation and the development of new technology for electrical grids changed over time. Furthermore, this paper describes the energy sector in terms of a business network comprising the different actors involved in innovation and development and, thus, their role in the energy supply chain.
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We show that optical and electrical phase conjugation enable effective nonlinear compensation, The impact of polarization mode dispersion and finite processing bandwidth on the ultimate limits are also considered.
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The argument that this paper sets out to critique is that in order to promote professionalism in Engineering Education and Practice, graduate level engineering programmes need to introduce the concepts of reflection and reflexivity into the curriculum right from the onset. By focusing upon the delivery of a newly developed „Work Based‟ Master’s level programme in Professional Engineering, this paper provides an overview of the first part of an empirical study which sets out to investigate the challenges associated with embedding reflection and reflexivity into Engineering Education. The paper concludes by noting that whilst student engineers may struggle with the concepts of reflection and reflexivity, with support and encouragement such difficulties can be overcome. Moreover, by encouraging students to reflect upon their Professional Practice, the programme not only enables students to consider how they may apply what they have learnt to their Professional Practice, but also encourages them to think about how they can link their experiences as Professional Engineers to what and how they learn both whilst on the programme but also as lifelong learners.
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This paper investigates the impact of state subsidy on the behavior of the entrepreneur under asymmetric information. Several authors formulated concerns about state intervention as it can aggravate moral hazard in corporate financing. In the seminal paper of Holmström and Tirole (1997) a two-player moral hazard model is presented with an entrepreneur initiating a risky scalable project and a private investor (e.g. bank or venture capitalist) providing outside financing. The novelty of our research is that this basic moral hazard model is extended to the case of positive externalities and to three players by introducing the state subsidizing the project. It is shown that in the optimum, state subsidy does not harm, but improves the incentives of the entrepreneur to make efforts for the success of the project; hence in effect state intervention reduces moral hazard. Consequently, state subsidy increases social welfare which is defined as the sum of private and public net benefits. Also, the exact form of the state subsidy (ex-ante/ex-post, conditional/unconditional, refundable/nonrefundable) is irrelevant in respect of the optimal size and the total welfare effect of the project. Moreover, in case of nonrefundable subsidies state does not crowd out private investors; but on the contrary, by providing additional capital it boosts private financing. In case of refundable subsidies some crowding effects may occur depending on the subsidy form and the parameters.
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The profitability of momentum portfolios in the equity markets is derived from the continuation of stock returns over medium time horizons. The empirical evidence of momentum, however, is significantly different across markets around the world. The purpose of this dissertation is to: (1) help global investors determine the optimal selection and holding periods for momentum portfolios, (2) evaluate the profitability of the optimized momentum portfolios in different time periods and market states, (3) assess the investment strategy profits after considering transaction costs, and (4) interpret momentum returns within the framework of prior studies on investors’ behavior. Improving on the traditional practice of selecting arbitrary selection and holding periods, a genetic algorithm (GA) is employed. The GA performs a thorough and structured search to capture the return continuations and reversals patterns of momentum portfolios. Three portfolio formation methods are used: price momentum, earnings momentum, and earnings and price momentum and a non-linear optimization procedure (GA). The focus is on common equity of the U.S. and a select number of countries, including Australia, France, Germany, Japan, the Netherlands, Sweden, Switzerland and the United Kingdom. The findings suggest that the evolutionary algorithm increases the annualized profits of the U.S. momentum portfolios. However, the difference in mean returns is statistically significant only in certain cases. In addition, after considering transaction costs, both price and earnings and price momentum portfolios do not appear to generate abnormal returns. Positive risk-adjusted returns net of trading costs are documented solely during “up” markets for a portfolio long in prior winners only. The results on the international momentum effects indicate that the GA improves the momentum returns by 2 to 5% on an annual basis. In addition, the relation between momentum returns and exchange rate appreciation/depreciation is examined. The currency appreciation does not appear to influence significantly momentum profits. Further, the influence of the market state on momentum returns is not uniform across the countries considered. The implications of the above findings are discussed with a focus on the practical aspects of momentum investing, both in the U.S. and globally.
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A plethora of recent literature on asset pricing provides plenty of empirical evidence on the importance of liquidity, governance and adverse selection of equity on pricing of assets together with more traditional factors such as market beta and the Fama-French factors. However, literature has usually stressed that these factors are priced individually. In this dissertation we argue that these factors may be related to each other, hence not only individual but also joint tests of their significance is called for. ^ In the three related essays, we examine the liquidity premium in the context of the finer three-digit SIC industry classification, joint importance of liquidity and governance factors as well as governance and adverse selection. Recent studies by Core, Guay and Rusticus (2006) and Ben-Rephael, Kadan and Wohl (2010) find that governance and liquidity premiums are dwindling in the last few years. One reason could be that liquidity is very unevenly distributed across industries. This could affect the interpretation of prior liquidity studies. Thus, in the first chapter we analyze the relation of industry clustering and liquidity risk following a finer industry classification suggested by Johnson, Moorman and Sorescu (2009). In the second chapter, we examine the dwindling influence of the governance factor if taken simultaneously with liquidity. We argue that this happens since governance characteristics are potentially a proxy for information asymmetry that may be better captured by market liquidity of a company's shares. Hence, we jointly examine both the factors, namely, governance and liquidity - in a series of standard asset pricing tests. Our results reconfirm the importance of governance and liquidity in explaining stock returns thus independently corroborating the findings of Amihud (2002) and Gompers, Ishii and Metrick (2003). Moreover, governance is not subsumed by liquidity. Lastly, we analyze the relation of governance and adverse selection, and again corroborate previous findings of a priced governance factor. Furthermore, we ascertain the importance of microstructure measures in asset pricing by employing Huang and Stoll's (1997) method to extract an adverse selection variable and finding evidence for its explanatory power in four-factor regressions.^
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General note: Title and date provided by Bettye Lane.