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This paper explores how Turkey’s politics and economy are affected by changes in global energy. To define which are the most relevant developments, the paper opens with an overview of the country's economic landscape. This analysis illustrates that energy, being the key driver behind its large current account deficit, represents a major point of vulnerability for the country. On this basis, the paper illustrates Turkey's energy matrix, an analysis that outlines the rising role of gas in the country's energy sector, both under the internal (i.e. growing share of the mix) and external (i.e. the country's potential role as regional gas hub) points of view. Finally, these issues are discussed with the aim of assessing the prospects for Turkey to turn gas into a geopolitical and economic asset for the country.

This paper reports the unified calculations of the optical band positions and spin-Hamiltonian parameters (g factors g//, g⊥ and zero-field splitting D) for two trigonal Cr3+ centers in Cs2NaGaF6: Cr3+ crystals. The calculations use the complete diagonalization of energy matrix method based on the two-spin-orbit-parameter model which takes account of the contributions from both the spin-orbit parameter of central dn ion (in the conventional crystal-field theory) and that of ligands. The calculated results are rationally coincident with the experimental values. The slight local lattice distortions in both Cr3+ centers are also estimated from the calculations and the causes are discussed.

This paper aims to show the current context of Small Hydro Power Plants (SHPs) in Brazil, presenting and discussing the institutional acts, regulations for growth of the SHP, public and private policies for the sector and growth prospects. After the restructuring of the Brazilian electricity sector, a series of laws, decrees and resolutions were developed with the purpose of regulating the sector in favor of SHPs. In 2001, the number of SHPs in Brazil was 303 with an installed capacity of 855 MW. Over the years, with the changes in the sector and, in 2010, the number of buildings has reached 387, with an installed capacity of 3428 MW. Today, they are 475 SHPs in operation with the generation capacity in the country, around 4799 MW, representing 3.49% of all Brazilian energy matrix. It is estimated that in 2020 the installed capacity will be approximately 6500 MW, but there is more potential available in the country for SHPs, that has great technical and environmental characteristics. It is concluded that more attention must be given by the government policies of the electricity sector to reach in the future the full the potential of SHPs available in Brazil.

This work tries to determine whether it is possible to stabilize CO2 emissions under a rapid increase of Gross Domestic Product in a medium term. The paper is an effort to study in detail how changes in the driving forces of the economy affect CO2 emissions. We study the case of Venezuela for the period 1980–2025, using the methodology proposed by Robalino-Lopez et al. (2014, 2013) [1] , [2] , which is based on an extension of the Kaya identity and on a GDP formation approach that includes the effect of renewable energies. We test the environmental Kuznets curve (EKC) [3] hypothesis in a coming future under different economic scenarios considering, therefore, not only past data but also projections for the coming years. We use cointegration techniques [4] and the Jaunky (2011) [5] specification to test the fulfillment of the EKC hypothesis in Venezuela. Our predictions show that Venezuela does not fulfill the EKC hypothesis, but however, the country could be on the way to achieve environmental stabilization in the medium term. This stabilization could be accomplished combining economic growth with increasing use of renewable energy, appropriated changes in the energy matrix, and in the productive sectoral structure.

The Ministry of Energy and Mines of Nicaragua (MEM) is planning to launch in 2013 a massive replacement program of 2 million incandescent lamps with compact fluorescent lamps (CFLs). This paper explores the expected impacts on a 10 year basis (2013–2023) using cost/benefit analysis for consumers, utility and society. Market conditions for introduction of a 7 W LED in the residential sector were also analyzed. Three prospective scenarios were considered in order to estimate the impact of CFLs penetration. Finally, the analysis is complemented with laboratory tests for eight lamps—three CFLs of the pilot program batch and one incandescent lamp 75 W; three CFLs and a 7 W LED available in the national market. Results supports that for countries like Nicaragua with an energy matrix still dependent on imported petroleum, energy efficiency programs are especially positive in economic and environmental terms. However, it is necessary to implement and to test CFLs programs requirements about high power factor (PF≥0.9) and low total harmonic distortion (THD≤20%).

The last 20 years have presented a favorable scenario for the incorporation of renewable energy sources into the energy matrix of developing countries. This situation promoted grid connected photovoltaic generation systems (GCPVS) to become one of the main protagonists in this new concept of energy matrix. In some developing countries the use of such systems is in its beginning. Promotion policies and technical as well as regulatory conditions for their installation have just started to be defined. In this context, there exists in Argentina a legal and regulatory framework for the implementation of large photovoltaic plants but there is a lack of such legal framework for distributed generation (DG) by means of grid connected photovoltaic into the medium and low voltage distribution networks. This situation led research centers, together with private and provincial Energy Agencies to install pilot systems in order to identify and characterize their impact on the low voltage distribution network, taking into account the local grid capacity and characteristics of each province. In this paper the implications of different degrees of penetration of solar photovoltaic power generation evaluated using technical parameters of the network is presented. A set of examples of residential users connected to a distribution substation in the city of Corrientes is analyzed by means of a simulation using real grid data with the incorporation of GCPVS generation. The simulation results show that both the level of penetration of GCPVS systems as well as location where these distributed energy sources should couple to the distribution grid must be carefully assessed to maximize the benefits of the inclusion of distributed generation in urban environments.

This paper reports an unified calculation of optical and EPR spectral data for Cr3+ ion at the trigonal Al3+ site of KAl(MoO4)2 crystal from the complete diagonalization (of energy matrix) method based on the two-spin–orbit-parameter model. In this model, differing from that in the conventional crystal-field theory, not only the contributions from the spin–orbit parameter of central dn ion, but also those from the spin–orbit parameter of ligand ion via covalence effect are taken into account. The calculation shows that by using only three adjustable parameters, the observed twelve optical and EPR spectral data (nine optical band positions and three EPR parameters g||, g⊥ and D) are reasonably explained in a unified way with this method. The results are discussed.

The EPR g factors g|| and g⊥ for two tetragonal Ce3+ centers T1 and T2 in Ce3+-doped cubic fluorperovskites KMgF3 and BaLiF3 are calculated from the complete diagonalization (of energy matrix) method (where all the Kramers doublets within the ground and excited multiplets 2F5/2 and 2F7/2 are contained). The calculations show that the simple method of calculating g factors (where only the doublets within the ground multiplet 2F5/2 are considered) used in the previous papers cannot give the correct signs of crystal-field parameter B 2 0 and hence the reasonable defect models for these tetragonal Ce3+ centers (in fact, physically, these defect models are inconsistent). The new and consistent defect models for these Ce3+ centers are suggested as follows: in KMgF3:Ce3+, centers T1 and T2 are the substitution of Ce3+ for K+ with a nearest interstitial F− and, respectively, with and without a nearest K+ vacancy (VK) along C4 axis, and in BaLiF3:Ce3+, centers T1 and T2 are the substitution of Ce3+ for Ba2+ with, respectively, a nearest interstitial F− and a nearest Ba2+ vacancy along C4 axis because of charge compensation. Based on these defect models and by considering the orbit reduction effect due to the covalence of Ce3+–F− bonds, the g factors of these tetragonal centers are explained reasonably. The results (in particular, the approximations of the defect structural data for these tetragonal centers) are discussed.

The aim of this paper is to model the crystal field parameters (CFPs) and spin-Hamiltonian parameters (g factors g | | , g ⊥ and hyperfine structure constants A | | , A ⊥ ) for the Ti3+:MgO system. The CFPs were modeled in the frame of superposition model of the crystal field theory, based on ab initio supercell calculations of Ti3+:MgO geometry and crystal field parameter 10Dq. The obtained values were used to simulate the energy levels scheme, by diagonalizing the full energy matrix of the Hamiltonian. The EPR parameters have been calculated from both the complete diagonalization method and the perturbation theory method. All the obtained results (optical and EPR) were compared with experimental data and a good agreement is observed.

The spin-Hamiltonian parameters (g factors g∥, g⊥ and hyperfine structure constants 143A∥, 143A⊥, 145A∥ and 145A⊥) of the tetragonal Nd3+ center in the low-temperature (T≈4.2 K) tetragonal phase of SrTiO3 are calculated from a diagonalization (of energy matrix) method. In the method, the Zeeman and hyperfine interaction terms are attached to the conventional Hamiltonian and a 52×52 energy matrix concerning the ground term 4HJ (J=9/2, 11/2, 13/2, 15/2) is constructed. The Nd3+ center is attributed to Nd3+ occupying the 12-fold coordinated Sr2+ site in SrTiO3. Differing from the defect model assumed in the previous paper that the tetragonal distortion of this Nd3+ center is due to the association of one interstitial oxygen ion at a nearest neighborhood of Nd3+ and the Nd3+ displacement Δz along C4 axis, we suggest that it is due to the distortion of SrTiO3 lattice in the tetragonal phase. The calculated g factors g∥ and g⊥ show good agreement with the experimental values, suggesting that our defect model of Nd3+ center in SrTiO3 is reasonable. The experimental hyperfine structure constants were not reported and so our calculated results remain to be checked by EPR experiment.

In this paper, the third-order perturbation formulas of EPR g factors g(i) (i=x, y, z) for d(9) ions in rhombic symmetry where the ground state being an vertical bar d(x2-y2)> admixture of and vertical bar d(z2)> states are derived. These formulas are based on a two-spin-orbit-parameter model in which the contributions to g factors due to both the spin-orbit parameter of the central 3d(n) ion and that of ligand ion are included. From these formulas, the g factors g(i) for the rhombic CuCl(6)(4-) clusters in (3-chloroanilinium)(8)[CdCl(6)]CL(4):Cu(2+) crystal are calculated. The calculated values are in good agreement with those obtained by the complete diagonalization (of energy matrix) method and experimental values. Results are discussed. (C) 2010 Elsevier B.V. All rights reserved.

Part II . The solution of the Schrodinger equation by means of the variation principle and a discrete basis leads to a certain secular equation. In a previous paper (Part I), it was shown that, if this equation is handled by a partitioning technique, a generalization of the Schrodinger-Brillouin formula is obtained. The procedure contains an inverse matrix, and it is shown here that, if in the expression for the wave function this matrix is approximated to the n th order, the corresponding matrix in the expectation value for the energy is approximated to order (2 n + 1). This gives a simple derivation and generalization of the Brillouin-Wigner theorem. The connection between the variation principle and perturbation theory is further discussed. Part III . The solution of the Schrodinger equation by means of the variation principle and a discrete but not necessarily orthonormal basis is studied in the case when the Hamiltonian H = H ( α ) is a function of a parameter α. The coefficients in the power series expansions in α of the wave function and the energy are explicitly determined in the form of expectation values, and the connection with the conventional Schrodinger theory is discussed.