Co-Simulation of IBC Type PFC Converter with Fuzzy Logic Controller

Many electronic power systems use bridge rectifiers, which are nonlinear, resulting in low power factor activity and high harmonic distortion due to the existence of nonlinear devices. To conform to harmonic standard requirements, longer device lifetime, and smooth operation of other devices in the system, power factor correction is required in these devices. The proposed system with an input power supply linked to a bridge rectifier which transforms ac to dc in this analysis, which is then linked to an Interleaved Boost Converter (IBC) with two parallel boost converters. The Interleaved Boost Converter uses Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) to work with the switches. The proportional controller gain has the effect of minimizing the time of increase and does not remove the error of steady-state. The result of removing the steady-state error is an integral control gain but deteriorate the transient response. The fuzzy controller takes inputs from the actual signals feedback values. Using the membership functions in the fuzzification method, the data provided to the fuzzy system is transformed into linguistic variables. To evaluate the performance, a series of rules that mimic the decision-making process of the human expert running the machine is then implemented using such inference mechanisms. Finally, a defuzzification block that transforms the output to a crisp value in such a manner that both structures are consistent. The proposed method is implemented using the software of MATLAB/Simulink and PSIM. The co-simulation result shows that the power factor achieved here is 0.9988, the Total Harmonic Distortion (THD) maintained is less than 5% and the average efficiency concluded here is 98% respectively. To verify the feasibility of the proposed scheme, a prototype model of a 5kW IBC type PFC converter is developed which is converting 230V AC input voltage to 400V DC output voltage, is implemented using a Microchip IC dsPIC33FJ16GS504. The experimental results are satisfactory, which uncover that a power factor is 0.9992 (close to unity), THD is 4.11; less than 5% and 98% overall efficiency at 100 kHz switching frequency, 230Vrms input voltage. With the higher performance, as a result, topology with high switching frequency makes a more compact, but costlier converter

Antimony doped tin oxide thin Films: Co gas sensor

in dioxide (SnO2) serves as an important base material in a variety of resistive type gas sensors. The widespread applicability of this semicoducting oxide is related both to its range of conductance variability and to the fact that it responds to both oxidising and reducing gases. The antimony doped tin-oxide films were prepared by spray pyrolysis method. The as-deposited films are blackish in colour. Addition of antimony impurity showed little increase in the thickness. The X-ray diffraction pattern shows characteristic tin oxide peaks with tetragonal structure. As the doping concentration of antimony was increased, new peak corresponding to Sb was observed. The intensity of this peak found to be increased when the Sb concentration was increased from 0.01 % to the 1 % which indicates the antimony was incorporated into the tin oxide. For gas sensing studies ohmic contacts were preferred to ensure the changes in resistance of sensor is due to only adsorption of gas molecule. The graph of I-V shows a straight line in nature which indicates the ohmic contact. The sensitivity of the sensor for CO gas was tested. The sensitivity of antimony doped tin oxide found to be increased with increasing Sb concentration. The maximum sensitivity was observed for Sb = 1 % at a working temperature of 250 °C. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2789

HAEMOCYTES OF THREE SCALE INSECT SPECIES: PHENACOCCUS GOSSYPII TOWNSEND & COCKERELL, PSEUDOCOCCUS LONGISPINUS (TARGIONI TOZZETTI) AND DACTYLOPIUS CONFUSUS (COCKERELL) (HEMIPTERA: COCCOIDEA)

HAEMOCYTES OF THREE SCALE INSECT SPECIES: PHENACOCCUS GOSSYPII TOWNSEND COCKERELL, PSEUDOCOCCUS LONGISPINUS (TARGIONI TOZZETTI) AND DACTYLOPIUS CONFUSUS (COCKERELL) (HEMIPTERA: COCCOIDEA) An evaluation of the haemocytes in the cochineal scale, Dactylopius confusus (Cockerell), was completed and compared with those found in the mealybugs Phenacoccus gossypii Townsend Cockerell and Pseudococcus longispinus (Targioni Tozzetti) to assess the potential sites of the dye pigment source. Four basic cell types were found in the two pseudococcids and five in the cochineal scale. The cell types common to all species included: prohaemocytes, oenocytoids, typical granulocytes and plasmatocytes. In addition, a modified granulocyte (poly-glyco-based granulocyte) was found to be specific to the cochineal scale and this produced rough endoplasmic reticulum derived granules that may be the source for the synthesis of carminic acid. Key words: function, Coleus, Philodendron, Opuntia, unknown cell type, haemolymph

Analytic and Asymptotic Methods for Nonlinear Singularity Analysis: a Review and Extensions of Tests for the Painlev\'e Property

The integrability (solvability via an associated single-valued linear problem) of a differential equation is closely related to the singularity structure of its solutions. In particular, there is strong evidence that all integrable equations have the Painlev\'e property, that is, all solutions are single-valued around all movable singularities. In this expository article, we review methods for analysing such singularity structure. In particular, we describe well known techniques of nonlinear regular-singular-type analysis, i.e. the Painlev\'e tests for ordinary and partial differential equations. Then we discuss methods of obtaining sufficiency conditions for the Painlev\'e property. Recently, extensions of \textit{irregular} singularity analysis to nonlinear equations have been achieved. Also, new asymptotic limits of differential equations preserving the Painlev\'e property have been found. We discuss these also.Comment: 40 pages in LaTeX2e. To appear in the Proceedings of the CIMPA Summer School on "Nonlinear Systems," Pondicherry, India, January 1996, (eds) B. Grammaticos and K. Tamizhman

The non-linear Schr\"odinger equation and the conformal properties of non-relativistic space-time

The cubic non-linear Schr\"odinger equation where the coefficient of the nonlinear term is a function $F(t,x)$ only passes the Painlev\'e test of Weiss, Tabor, and Carnevale only for $F=(a+bt)^{-1}$, where $a$ and $b$ are constants. This is explained by transforming the time-dependent system into the constant-coefficient NLS by means of a time-dependent non-linear transformation, related to the conformal properties of non-relativistic space-time. A similar argument explains the integrability of the NLS in a uniform force field or in an oscillator background.Comment: Thoroughly revised version, in the light of new interest in non-relativistic conformal tranformation, with a new reference list. 8 pages, LaTex, no figures. To be published in Int. J. Theor. Phy

Dynamical aspects of mean field plane rotators and the Kuramoto model

The Kuramoto model has been introduced in order to describe synchronization phenomena observed in groups of cells, individuals, circuits, etc... We look at the Kuramoto model with white noise forces: in mathematical terms it is a set of N oscillators, each driven by an independent Brownian motion with a constant drift, that is each oscillator has its own frequency, which, in general, changes from one oscillator to another (these frequencies are usually taken to be random and they may be viewed as a quenched disorder). The interactions between oscillators are of long range type (mean field). We review some results on the Kuramoto model from a statistical mechanics standpoint: we give in particular necessary and sufficient conditions for reversibility and we point out a formal analogy, in the N to infinity limit, with local mean field models with conservative dynamics (an analogy that is exploited to identify in particular a Lyapunov functional in the reversible set-up). We then focus on the reversible Kuramoto model with sinusoidal interactions in the N to infinity limit and analyze the stability of the non-trivial stationary profiles arising when the interaction parameter K is larger than its critical value K_c. We provide an analysis of the linear operator describing the time evolution in a neighborhood of the synchronized profile: we exhibit a Hilbert space in which this operator has a self-adjoint extension and we establish, as our main result, a spectral gap inequality for every K>K_c.Comment: 18 pages, 1 figur

Microscopic mechanisms of dephasing due to electron-electron interactions

We develop a non-perturbative numerical method to study tunneling of a single electron through an Aharonov-Bohm ring where several strongly interacting electrons are bound. Inelastic processes and spin-flip scattering are taken into account. The method is applied to study microscopic mechanisms of dephasing in a non-trivial model. We show that electron-electron interactions described by the Hubbard Hamiltonian lead to strong dephasing: the transmission probability at flux $\Phi=\pi$ is high even at small interaction strength. In addition to inelastic scattering, we identify two energy conserving mechanisms of dephasing: symmetry-changing and spin-flip scattering. The many-electron state on the ring determines which of these mechanisms will be at play: transmitted current can occur either in elastic or inelastic channels, with or without changing the spin of the scattering electron.Comment: 11 pages, 16 figures Submitted to Phys. Rev.

3D evolution of a filament disappearance event observed by STEREO

A filament disappearance event was observed on 22 May 2008 during our recent campaign JOP 178. The filament, situated in the southern hemisphere, showed sinistral chirality consistent with the hemispheric rule. The event was well observed by several observatories in particular by THEMIS. One day before the disappearance, H$\alpha$ observations showed up and down flows in adjacent locations along the filament, which suggest plasma motions along twisted flux rope. THEMIS and GONG observations show shearing photospheric motions leading to magnetic flux canceling around barbs. STEREO A, B spacecraft with separation angle 52.4 degrees, showed quite different views of this untwisting flux rope in He II 304 \AA\ images. Here, we reconstruct the 3D geometry of the filament during its eruption phase using STEREO EUV He II 304 \AA\ images and find that the filament was highly inclined to the solar normal. The He II 304 \AA\ movies show individual threads, which oscillate and rise to an altitude of about 120 Mm with apparent velocities of about 100 km s$^{-1}$, during the rapid evolution phase. Finally, as the flux rope expands into the corona, the filament disappears by becoming optically thin to undetectable levels. No CME was detected by STEREO, only a faint CME was recorded by LASCO at the beginning of the disappearance phase at 02:00 UT, which could be due to partial filament eruption. Further, STEREO Fe XII 195 \AA\ images showed bright loops beneath the filament prior to the disappearance phase, suggesting magnetic reconnection below the flux rope

Confinement and Chiral Symmetry Breaking via Domain-Like Structures in the QCD Vacuum

A qualitative mechanism for the emergence of domain structured background gluon fields due to singularities in gauge field configurations is considered, and a model displaying a type of mean field approximation to the QCD partition function based on this mechanism is formulated. Estimation of the vacuum parameters (gluon condensate, topological susceptibility, string constant and quark condensate) indicates that domain-like structures lead to an area law for the Wilson loop, nonzero topological susceptibility and spontaneous breakdown of chiral symmetry. Gluon and ghost propagators in the presence of domains are calculated explicitly and their analytical properties are discussed. The Fourier transforms of the propagators are entire functions and thus describe confined dynamical fields.Comment: RevTeX, 48 pages (32 pages + Appendices A-E), new references added [1,2,4,5] and minor formulae corrected for typographical error

A Conformally Invariant Holographic Two-Point Function on the Berger Sphere

We apply our previous work on Green's functions for the four-dimensional quaternionic Taub-NUT manifold to obtain a scalar two-point function on the homogeneously squashed three-sphere (otherwise known as the Berger sphere), which lies at its conformal infinity. Using basic notions from conformal geometry and the theory of boundary value problems, in particular the Dirichlet-to-Robin operator, we establish that our two-point correlation function is conformally invariant and corresponds to a boundary operator of conformal dimension one. It is plausible that the methods we use could have more general applications in an AdS/CFT context.Comment: 1+49 pages, no figures. v2: Several typos correcte