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The ability of the Distributed Generation (DG) to solve problems such as power system deregulation and power demand problems appropriate to its purpose, which is to inject electricity in a distributed manner at a point close to the load, causes the distributed generation to become the latest trend in electricity generation technology. Proper position of distributed generation is necessary in order to achieved maximum benefit from DG, which could be due to an incorrect allocation of DG sources to the power network would not only result in increased power losses, but could also jeopardize the operation of the system. This paper introduces an ACO-algorithm for optimal location of DGs using a real network in one of a rural area of Malaysia. The method is used to determine the effectiveness of DG by comparing the losses of power and the improvement of the voltage profile. As for the confirmation to the ACO method, another method known as brute force method is use to compare the data gain as validation purposes.

First-principles studies were conducted to investigate the structural, elastic and electronic properties of the Cd-containing synthesized MAX phase Ti2CdC in comparison with the predicted phase Ti2CdN. Our calculations show that the substitution of C by N in Ti2CdC mostly affects the lattice constant c; the lattice constant a remains almost unchanged. All the elastic constants and moduli increase when C is replaced by N. In comparison with the Ti2CdN phase, Ti2CdC is more compressible along the c-axis. The elastic anisotropy in Ti2CdC is higher in comparison with Ti2CdN. Both the two nanolaminates are brittle in nature. The calculated electronic band structures and density of states imply that the chemical bonding in these two compounds is a combination of covalent, ionic and metallic nature. Electrically, Ti2CdC is more conducting than Ti2CdN.

The nature of the variation of oxygen isotope exponent (IE) with the number of doped holes, p, in the CuO2 planes has been a source of considerable debate. The large IE over certain range of hole concentrations always casts a shadow over any proposal where non-phononic mechanism is invoked to describe pairing in cuprates. On the other hand, existing theoretical schemes, based on electron-phonon interactions, cannot describe the anomalous features shown by the IE as a function of hole concentration/disorder, either quantitatively or qualitatively. Based on an experiment relating the possibility of Fermi-surface reconstruction to the thermoelectric transport measurements (Laliberté et al. Nature Commun. 2, 432 (2011)), we propose here a simple scenario where isotope substitutions affect the charge/spin stripe state via the coupling to the underlying lattice and thereby change the superconducting Tc . In this picture, significant part of the IE, over an extended p-range, actually originates from the isotope induced stripe modulation and is not directly related to the characteristic energy scale of the phonons mediating the Cooper pairing. This proposal qualitatively explains all the disorder- and p-dependent features of the IE seen in hole doped high-Tc cuprates. We also provide with an outline of some experiments that can verify the degree of validity of the proposed scheme.

The anomalous behaviour of dc charge dynamics in high-Tc cuprates cannot be explained by the prevalent Boltzman transport theory. In high-Tc cuprates the in-plane and out-of-plane dc resistivities exhibit high anisotropy and unconventional temperature dependence. In this study we have modeled the temperature (T) and hole content (p) dependent in-plane resistivity, ρa (T, p), of pure and Ca doped Y123 (Y(Ca)Ba2Cu3O7- δ ). We have adapted and extended the formalism developed by Naqib et al. (Physica C 471 1598 (2011)) by taking account of two generic features present in all hole doped cuprates, namely - (i) the presence of the pseudogap in the quasiparticle spectrum and (ii) high-T linear behavior, to elucidate non-Fermi liquid ρa (T, p) of Y(Ca)Ba2Cu3O7- δ over a wide range of temperature and hole contents. The characteristic pseudogap energy scale, εg (p), extracted from the analysis of the resistivity data was found to agree well with those found in a variety of earlier studies. Other extracted parameters from the analysis of ρp (T, p) data showed methodical variations with the variation of hole content. Important features of the analysis are briefly discussed.

Ab intio calculations were carried out on the structural, elastic, and electronic properties of a newly synthesized ternary silicide superconductor, Li2IrSi3. The obtained lattice parameters show sound agreement with the experimental values, indicating the reliability of the present study. The rigid structure of Li2IrSi3 is due to the strong covalent Ir-Si and Si-Si bonding. The new compound is mechanically stable, brittle and elastically anisotropic. The relatively low value of the Poisson’s ratio for Li2IrSi3 is indicative of its high degree of directional covalent bonding.

Density functional theory based investigations of structural, elastic, electronic band structure, and optical properties of superconducting ternary phosphides (BaM2P2; M = Ni, Rh) have been carried out. Calculated ambient condition properties are compared with experimental and theoretical results, where available. Pressure dependent electronic density of states at the Fermi level, N(EF), and the Debye temperature, D, have been explored and their effect on the superconducting transition temperature have been disclosed. N(EF) shows nonmonotonic pressure dependence in BaNi2P2. Pressure dependence of N(EF) for BaRh2P2, on the other hand, is systematic. Pressure dependence of N(EF) affects superconducting transition temperature significantly. Debye temperature increases with increasing pressure. Variation of optical parameters with photon energy show metallic behavior complementing the features of electronic band structure calculations. Absorption coefficient of BaNi2P2 exhibits strong optical absorption in ultraviolet region, while BaRh2P2 absorbs photons over a wider energy band including the entire visible range. Reflectivity spectra for both BaNi2P2 and BaRh2P2 reveal that they are strong reflectors of visible light and BaNi2P2 in particular holds significant promise to be used as coating material to reduce solar heating.

The effect of Zn substitution on the superconducting transition temperature, Tc, was investigated for the sintered Y1-xCaxBa2(Cu1-yZny)3O7-delta compounds over a wide range of hole concentration per CuO2 plane, p. Ca substitution enabled us to study the deeply overdoped region. p was changed by changing the oxygen deficiency (delta). A strongly p-dependent rate of suppression of Tc with Zn (dTc/dy) was found. From the analysis of the dTc(p)/dy and Tc(p,y) data, we found that the optimum hole content, popt, shifts to higher values with increasing Zn and superconductivity is at its strongest when p = 0.185 +/- 0.005. Various complementary experiments have identified this as the hole content where the pseudogap vanishes quite abruptly. We have discussed the possible relevance to these ideas with our findings.

Critical current measurements were made on thin films of YBa2Cu3O7-delta and Y0.8Ca0.2Ba2Cu3O7-delta produced by sol-gel and pulsed laser deposition, respectively. Both samples have high critical currents at low temperatures and the critical current, Jc, is largest in the overdoped Y0.8Ca0.2Ba2Cu3O7-delta thin film. Annealing studies show a large increase in Jc with increasing hole concentration and suggests that the maximum Jc should occur for overdoped samples. The very overdoped region of the superconducting phase diagram was probed by studying bulk ceramic Y0.8Ca0.2Ba2Cu3O7-delta samples, where it was found that the irreversibility field systematically increases with increasing hole concentration when scaled by the reduced temperature (t = (1 - T/Tc))., Comment: To appear in Supercond.Sci.Technol.17 (2004)S1-S5

Continuum energy spectra of the transfer reaction at 50 MeV are calculated and compared with experiment. A numerical treatment of the finite range distorted-wave Born approximation (DWBA) is used, with a strong absorption parameterisation of the radial matrix elements. The parameters of the S-matrix in the entrance and exit channels are obtained from elastic scattering data using a strong absorption parameterisation.

In Abrasive Waterjet (AWJ) machining, the nozzle is the most critical component that influences the performance, precision and economy. Exposure to a high speed jet and abrasives makes it susceptible to wear erosion which requires for frequent replacement. The present works attempts to simulate the erosion of the nozzle wall using computational fluid dynamics. The erosion rate of the nozzle was simulated under different operating conditions. The simulation was carried out in several steps which is flow modelling, particle tracking and erosion rate calculation. Discrete Phase Method (DPM) and K-e turbulence model was used for the simulation. Result shows that different operating conditions affect the erosion rate as well as the flow interaction of water, air and abrasives. The simulation results correlates well with past work.

The structural, elastic, and electronic properties of the very recently discovered ternary silicide superconductor, Li2IrSi3, are calculated using an ab-initio technique. We adopt the plane-wave pseudopotential approach within the framework of the first-principles density functional theory (DFT) implemented by the CASTEP code. The calculated structural parameters show reasonable agreement with the experimental results. The elastic moduli of this interesting material are calculated for the first time. The electronic band structure and electronic energy density of states indicate the strong covalent Ir–Si and Si–Si bonding, which leads to the formation of the rigid structure of Li2IrSi3. Strong covalency gives rise to a high Debye temperature in this system. We discuss the theoretical results in detail in this paper.

In conventional superconductors the magnitude of the pairing fluctuation is primarily determined by Tc and the superconducting coherence length ?. In low-dimensional systems with strong structural and electronic anisotropies, the interlayer separation s plays a significant role. In cuprates, the pseudogap (PG) correlation induces a downturn in the temperature-dependent resistivity. As Tc is approached from above, this downturn in the resistivity is supposed to either (i) add independently to, or (ii) join smoothly to that due to paraconductivity caused by short-lived Cooper pairs. It is important to differentiate between these two possibilities, since they are closely linked to the nature of the PG. It would be reasonable to assume that if the first scenario is correct, then the PG has a non-superconducting origin, while the second scenario, if found to hold, would relate precursor pairing to the PG correlations. In this paper we have studied the in-plane fluctuation conductivity of two c-axis-oriented thin films of Y0.95Ca0.05Ba2Cu3O7?? with similar hole contents (p), p?=?0.165 (optimally doped (OPD)) and p?=?0.184 (slightly overdoped (SOD)). The hole contents are fixed at these values so that the PG affects the slope of the resistivity data only at temperatures close to Tc. Analysis of paraconductivity ??ab(T) within the mean-field Gaussian Ginzburg?Landau (MFGGL) framework reveals different qualitative and quantitative features for the OPD and the SOD compounds. The excess conductivity due to Cooper pair fluctuations of the SOD sample can be described reasonably well by the MFGGL formalism. The excess conductivity of the OPD compound, on the other hand, cannot be accounted for by the MFGGL formalism with a reasonable set of parameters. There is a significant added contribution to ??ab(T) for the OPD sample that appears to come from the presence of a PG in the quasiparticle (QP) spectral density. These findings point towards a non-pairing origin of the PG.

The nature of resistive transition of high-quality crystalline thin films of YBa2Cu3O7−δ has been studied under magnetic fields (H) applied along the c direction over a wide range of doped holes, p in the CuO2 planes. The field- and temperature-dependent in-plane resistivity, ρ ab(T, H), has been analyzed within the thermally assisted flux-flow (TAFF) formalism. The flux activation energy, U(T, H), has been extracted from this analysis. The low-T part of the ρab(T, H) data can be described by an activation energy having the functional form of U(T, H) = (1-t)m(H0/H)−β, where t=T/Tc (reduced temperature), and H0 is a field scale that primarily determines the magnitude of U(T, H). The temperature exponent, m, shows a systematic variation with p, whereas the field exponent, β , is insensitive to the p values and is close to unity. The H0, on the other hand, changes rapidly as p is varied. U(T, H) is linked to the pinning potential and consequently on the superconducting condensation energy. Since the normal state pseudogap directly affects superconducting condensation energy, a clear correspondence between H0 and the PG energy scale, ɛg, is found. Possible implications of these results are discussed.

The effect of controlled disorder on the superconducting transition temperature, Tc, resistivity, and the magnitude of the field-cooled ac susceptibility (ACS) has been investigated for Ca and Zn substituted Y123 (Y0.80Ca0.20Ba2(Cu1 − yZny)3O7 − δ) sintered compounds over a wide range of compositions. Ca was used to explore the overdoped side. The in-plane hole content, p, was changed by varying the oxygen deficiency (δ). Irrespective of the hole content, Tc decreased almost linearly with Zn, though the rate of suppression was strongly p dependent. The magnitude of the low-field, field-cooled ACS, on the other hand, decreased abruptly and significantly for the heavily disordered (y > 0.05) sintered compounds when p was decreased. More strikingly, the qualitative features of the field dependent ACS signal became identical for sintered and powdered samples, indicating a complete absence of coupling among superconducting grains in heavily disordered Y0.80Ca0.20Ba2(Cu1 − yZny)3O7 − δ. A non-monotonic and pronounced enhancement of the residual resistivity for samples with y > 0.05 lends further support to this picture. The abruptness of this 'isolated superconducting droplet' behavior points toward possible interplay among various length scales. We discuss the implications of these findings in detail in this paper.

We have studied the Nernst coefficient, ?(T), of epitaxial thin films of the superconductor Y1-xCaxBa2Cu3Oy with x=0.05 and x=0.1. The x=0.1 sample has been measured at three different values of y, in the over- (OV), optimally- (OP), and under-doped (UD) states. As the doping level is reduced, ?(T) starts to fall linearly with T at the temperature (T*) where we expect to see the influence of the pseudogap. The onset temperature of the superconducting fluctuation contribution to ?(T) was found to vary slowly with the hole concentration (p) between p=0.118 and 0.197. For the OP and UD samples, ?(T>T*) is unusually large, being comparable with |S?tan??| where S is the Seebeck coefficient and ? the Hall angle.

The effect of Zn substitution on the superconducting transition temperature, Tc, was investigated for the La2−xSrxCu1−yZnyO4 (Zn-LSCO) compounds over a wide range of hole concentrations, p (), and Zn content (y) in the CuO2 plane. A Zn-induced rate of suppression of Tc, dTc(p)/dy, was found to be strongly p-dependent and showed a systematic variation with hole concentration, except in the vicinity of p~0.12, i.e. near the so-called 1/8th anomaly where the charge/spin stripe correlations are at their strongest in La2−xSrxCuO4. Near p~0.12, the static striped charge ordering is widely believed to dominate the T–p phase diagram. dTc(p)/dy decreased strongly around this hole concentration i.e. Zn became less effective in degrading Tc near p~0.12. This observation is indicative of an intricate and competing interplay among the superconducting, pseudogap, and stripe correlations in Zn substituted LSCO.

The effect of added holes per CuO2 plane, p, on the temperature-dependent uniform (q = 0, where q is the wavevector) magnetic susceptibility, χ(T), of double CuO2 plane YBa2Cu3O7−δ and single CuO2 plane La2−xSrxCuO4 compounds was investigated over a wide range of oxygen deficiencies (δ) and Sr contents (x). Systematic variations in χ(T) were found with changing p. The characteristic pseudogap energy scale, eg(p), was extracted from the analysis of the χ(T,p) data. From the evolution of eg(p), we have found quite abrupt signs of the pseudogap in the quasi-particle spectral density appearing first at around a planar hole content of p = 0.190 ± 0.005. eg(p) rapidly grows (almost linearly) with decreasing p. In the heavily underdoped region, eg(p) extrapolates to ~Jex (the antiferromagnetic exchange energy of the parent compound) as . These characteristic features of the pseudogap energy scale are almost identical for YBa2Cu3O7−δ and La2−xSrxCuO4 even though the superconducting transition temperature, Tc, and anisotropy are widely different for these two compounds. We have scrutinized different existing scenarios for the pseudogap in the light of our findings.

The 66Zn(d,p)67Zn reaction has been studied at a bombarding energy of 12 MeV. The ground-state Q value was determined to be 4.820+or-0.006 MeV. Excitation energies were obtained for 76 levels below Ex=4.59 MeV in 67Zn. The levels of Ex=1.604, 2.753, 2.883, 3.326, 3.429, 3.699, 3.907, 3.946, 3.981, 4.135, 4.186, 4.225, 4.257, 4.286, 4.368, 4.388, 4.457, 4.556, 4.593 MeV are established for the first time in a (d,p) reaction. The scale of absolute cross sections for the (d,p) reaction was determined within +or-9% accuracy through direct comparison of (d,p) and (d,d) reactions on 66Zn. Angular distributions were measured for 27 (d,p) transitions over the angular range (5 degrees -65 degrees ); ln values and spectroscopic factors were deduced using DWBA analysis.

From collective model sum rules derived from the various possible intermediate couplings of a zero coupled product of four E2 operators, approximate expressions are obtained for the reduced transition probability B(E2,4+ to 2+) and the magnitude of the static quadrupole moment mod Q2+ mod of the first 2+ state for an even-even nucleus in terms of other E2 transition strengths.