Raman & Infrared Study of Bi Filled Co4Sb12

CoSb3 skutterudites are established thermoelectric materials in the 500-800K temperature range. Undoped and Bi filled CoSb3 samples were synthesized by induction melting-annealing process and phase confirmation done by X-Ray diffraction. The role of bismuth as a filler in CoSb3 was investigated by Raman and far infrared reflectance study. It was found that bismuth strengthens Sb vibrations, and can potentially scatter Sb related acoustic phonons effectively. As a result substantial reduction in thermal conductivity may be possible with proper control of Bi filling.

Optical properties change with the addition and diffusion of Bi to As2S3 in the Bi/As2S3 bilayer thin film

The role of Bi layer (thickness similar to 7 nm) on As2S3 film was extensively studied for different optical applications in which Bi (top layer) as active and diffusing layer and As2S3 as barrier (matrix) layer. Bilayer thin films of Bi/As2S3 were prepared from Bi and As2S3 by thermal evaporation technique under high vacuum. The decrease of optical band gap with the addition of Bi to As2S3 has been explained on the basis of density of states and the increase in disorder in the system. It was found that the efficient changes of optical parameters (transmission, optical band gap, refraction) could be realized due to the photo induced diffusion activated by the focused 532 nm laser irradiation and formation of different bonds. The diffusion of Bi into As2S3 matrix increases the optical band gap producing photo bleaching effect. The changes were characterised by different experimental techniques. (C) 2012 Elsevier B.V. All rights reserved.

Implication of a Higgs boson at 125 GeV within the stochastic superspace framework

We revisit the issue of considering stochasticity of Grassmannian coordinates in N = 1 superspace, which was analyzed previously by Kobakhidze et al. In this stochastic supersymmetry (SUSY) framework, the soft SUSY breaking terms of the minimal supersymmetric Standard Model (MSSM) such as the bilinear Higgs mixing, trilinear coupling, as well as the gaugino mass parameters are all proportional to a single mass parameter xi, a measure of supersymmetry breaking arising out of stochasticity. While a nonvanishing trilinear coupling at the high scale is a natural outcome of the framework, a favorable signature for obtaining the lighter Higgs boson mass m(h) at 125 GeV, the model produces tachyonic sleptons or staus turning to be too light. The previous analyses took Lambda, the scale at which input parameters are given, to be larger than the gauge coupling unification scale M-G in order to generate acceptable scalar masses radiatively at the electroweak scale. Still, this was inadequate for obtaining m(h) at 125 GeV. We find that Higgs at 125 GeV is highly achievable, provided we are ready to accommodate a nonvanishing scalar mass soft SUSY breaking term similar to what is done in minimal anomaly mediated SUSY breaking (AMSB) in contrast to a pure AMSB setup. Thus, the model can easily accommodate Higgs data, LHC limits of squark masses, WMAP data for dark matter relic density, flavor physics constraints, and XENON100 data. In contrast to the previous analyses, we consider Lambda = M-G, thus avoiding any ambiguities of a post-grand unified theory physics. The idea of stochastic superspace can easily be generalized to various scenarios beyond the MSSM. DOI: 10.1103/PhysRevD.87.035022

An Optimal Fuzzy Logic Controller tuned with Artificial Immune System

In this paper, a method for the tuning the membership functions of a Mamdani type Fuzzy Logic Controller (FLC) using the Clonal Selection Algorithm(CSA) a model of the Artificial Immune System(AIS) paradigm is examined. FLC's are designed for two problems, firstly the linear cart centering problem and secondly the highly nonlinear inverted pendulum problem. The FLC tuned by AIS is compared with FLC tuned by GA. In order to check the robustness of the designed PLC's white noise was added to the system, further, the masses of the cart and the length and mass of the pendulum are changed. The PLC's were also tested in the presence of faulty rules. Finally, Kruskal Wallis test was performed to compare the performance of the GA and AIS. An insight into the algorithms are also given by studying the effect of the important parameters of GA and AIS.

Thermoelectric properties of Bi-added Co4Sb12 skutterudites

Void filling in (I) Bi-x-added Co4Sb12 or (II) Sb/Bi substitution of Co4Sb12-xBix has been investigated for structural and thermoelectric properties evaluation. X-ray powder data Rietveld refinements combined with electron probe microanalyses showed a polycrystalline and practically Bi-free CoSb3 skutterudite phase as the major constituent as well as a secondary Bi phase in the grain boundaries. For series I alloys, the electrical conductivity, Seebeck coefficient and thermal conductivity were measured as a function of temperature in the range from 450 to 750 K. The electrical conductivity of all the samples increased with increasing temperature, showing a semiconducting nature with smaller values of the Seebeck coefficient for higher Bi fractions. Conduction over the entire temperature range was found to arise from a single p-type carrier. Thermal conductivity showed a reduction with Bi added in all the samples, except for Bi0.75Co4Sb12, and the lowest lattice thermal conductivity was found for a Bi-added fraction of 0.5. The maximum zT value of 0.53 at 632 K is higher than that of Co4Sb12.

Network congestion management by fuzzy inference using virtual flows

Effective network overload alleviation is very much essential in order to maintain security and integrity from the operational viewpoint of deregulated power systems. This paper aims at developing a methodology to reschedule the active power generation from the sources in order to manage the network congestion under normal/contingency conditions. An effective method has been proposed using fuzzy rule based inference system. Using virtual flows concept, which provides partial contributions/counter flows in the network elements is used as a basis in the proposed method to manage network congestions to the possible extent. The proposed method is illustrated on a sample 6 bus test system and on modified IEEE 39 bus system.

Comparison of one cycle control of charge and current for bi-directional boost rectifiers

Classical control and one cycle control of current are popular methods used to modulate pulses in active rectifiers for ac-dc power conversion. One cycle control has lower control complexity and can be implemented using linear analog circuits when compared with the classical approach. However, it also suffers from problems such as instability and offsets in current that is severe at light load conditions. A control strategy for bidirectional boost rectifiers based on one cycle control of charge is proposed for that overcomes these limitations. The integral of sensed current, which represents charge, is compared with a non-linear carrier, which is modified for ac-dc power conversion. This generates the gating signals for the switching devices. The modifications required for the control law governing one cycle control of charge is derived in the paper. Detailed simulation studies are carried out to compare one cycle control of current with the proposed method for ac-dc power conversion, which are validated on a laboratory hardware prototype.

Fuzzy data envelopment analysis for performance evaluation of an irrigation system

Sixteen irrigation subsystems of the Mahi Bajaj Sagar Project, Rajasthan, India, are evaluated and selection of the most suitable/best is made using data envelopment analysis (DEA) in both deterministic and fuzzy environments. Seven performance-related indicators, namely, land development works (LDW), timely supply of inputs (TSI), conjunctive use of water resources (CUW), participation of farmers (PF), environmental conservation (EC), economic impact (EI) and crop productivity (CPR) are considered. Of the seven, LDW, TSI, CUW, PF and EC are considered inputs, whereas CPR and EI are considered outputs for DEA modelling purposes. Spearman rank correlation coefficient values are also computed for various scenarios. It is concluded that DEA in both deterministic and fuzzy environments is useful for the present problem. However, the outcome of fuzzy DEA may be explored for further analysis due to its simple, effective data and discrimination handling procedure. It is inferred that the present study can be explored for similar situations with suitable modifications.

Gene expression programming-fuzzy logic method for crop type classification

Crop type classification using remote sensing data plays a vital role in planning cultivation activities and for optimal usage of the available fertile land. Thus a reliable and precise classification of agricultural crops can help improve agricultural productivity. Hence in this paper a gene expression programming based fuzzy logic approach for multiclass crop classification using Multispectral satellite image is proposed. The purpose of this work is to utilize the optimization capabilities of GEP for tuning the fuzzy membership functions. The capabilities of GEP as a classifier is also studied. The proposed method is compared to Bayesian and Maximum likelihood classifier in terms of performance evaluation. From the results we can conclude that the proposed method is effective for classification.

Black hole formation in fuzzy sphere collapse

We study the collapse of a fuzzy sphere, that is a spherical membrane built out of D0-branes, in the Banks-Fischler-Shenker-Susskind model. At weak coupling, as the sphere shrinks, open strings are produced. If the initial radius is large then open string production is not important and the sphere behaves classically. At intermediate initial radius the backreaction from open string production is important but the fuzzy sphere retains its identity. At small initial radius the sphere collapses to form a black hole. The crossover between the later two regimes is smooth and occurs at the correspondence point of Horowitz and Polchinski.

Monopoles on S-F(2) from the fuzzy conifold

The intersection of the conifold z(1)(2) + z(2)(2) + z(3)(2) = 0 and S-5 is a compact 3-dimensional manifold X-3. We review the description of X-3 as a principal U(1) bundle over S-2 and construct the associated monopole line bundles. These monopoles can have only even integers as their charge. We also show the Kaluza-Klein reduction of X-3 to S-2 provides an easy construction of these monopoles. Using the analogue of the Jordan-Schwinger map, our techniques are readily adapted to give the fuzzy version of the fibration X-3 -> S-2 and the associated line bundles. This is an alternative new realization of the fuzzy sphere S-F(2) and monopoles OH it.

Integrated sustainable irrigation planning with multiobjective Fuzzy optimization approach

Multiobjective fuzzy methodology is applied to a case study of Khadakwasla complex irrigation project located near Pune city of Maharashtra State, India. Three objectives, namely, maximization of net benefits, crop production and labour employment are considered. Effect of reuse of wastewater on the planning scenario is also studied. Three membership functions, namely, nonlinear, hyperbolic and exponential are analyzed for multiobjective fuzzy optimization. In the present study, objective functions are considered as fuzzy in nature whereas inflows are considered as dependable. It is concluded that exponential and hyperbolic membership functions provided similar cropping pattern for most of the situations whereas nonlinear membership functions provided different cropping pattern. However, in all the three cases, irrigation intensities are more than the existing irrigation intensity.

Anomalous polarization in the antiferroelectric-ferroelectric phase coexistence state in PbZrO3-Bi(Mg1/2Ti1/2)O-3

The ferroelectric system (1-x)PbZrO3-(x)Bi(Mg1/2Ti1/2)O-3 has been investigated as a function of composition, temperature, and electric field by x-ray powder diffraction, dielectric, and ferroelectric measurements. Within the solubility limit (x similar to 0.25), the system evolves from an orthorhombic-antiferroelectric to rhombohedral-ferroelectric state through a phase coexistence region. The highest polarization was found not for the composition exhibiting a pure ferroelectric state, but for a composition x = 0.15 exhibiting ferroelectric + antiferroelectric phase coexistence close to the rhombohedral phase boundary. Electric poling of the equilibrium two-phase state led to irreversible enhancement in the rhombohedral phase fraction suggesting that the enhanced polarization is related to the enhanced polarizability of the lattice due to first order criticality as in ferroelectric-ferroelectric morphotropic phase boundary systems. (C) 2013 AIP Publishing LLC.

FUZZY CONIFOLD Y-F(6) AND MONOPOLES ON S-F(2) x S-F(2)

In this paper, we construct the fuzzy (finite-dimensional) analogs of the conifold Y-6 and its base X-5. We show that fuzzy X-5 is (the analog of) a principal U(1) bundle over fuzzy spheres S-F(2) x S-F(2) and explicitly construct the associated monopole bundles. In particular, our construction provides an explicit discretization of the spaces T-k,T-k and T-k,T-0.

CFD Analysis of two phase flow with a prediction of torque demand of a Bi-lobe rotor of a mixing chamber

An attempt to study the fluid dynamic behavior of two phase flow comprising of solid and liquid with nearly equal density in a geometrical case that has an industrial significance in theareas like processing of polymers, food, pharma ceutical, paints. In this work,crystalline silica is considered as the dispersed medium in glycerin. In the CFD analysis carried out,the two phase components are considered to be premixed homogeneously at the initial state. The flow in a cylinder that has an axially driven bi-lobe rotor, a typical blender used in polymer industry for mixing or kneading to render the multi-component mixture to homogeneous condition is considered. A viscous, incompressible, isothermal flow is considered with an assumption that the components do not undergo any physical change and the solids are rigid and mix in fully wetting conditions. Silica with a particle diameter of 0.4 mm is considered and flow is analyzed for different mixing fractions. An industry standard CFD code is used for solving 3D-RANS equations. As the outcome of the study the torque demand by the bi-lobe rotor for different mixture fractions which are estimated show a behavioral consistency to the expected physical phenomena occurring in the domain considered.