Phase Voltage Harmonic Imbalance in Asymmetrical Multiphase Machines with Single Neutral Point

Multiphase (n-phase) machines are often designed with l sub-windings on stator, each having k phases, and the machine is typically operated with l isolated neutral points. However, such a machine can also operate with a single neutral point, which improves the fault-tolerant properties. When a machine is inverter supplied, low order harmonics may be present due to the low switching frequency and nonlinear inverter properties. Moreover, low order zero-sequence harmonics can be deliberately injected to increase dc bus voltage utilisation. This paper investigates a phenomenon that has not been reported so far in relation to asymmetrical multiphase machines with a single neutral point, namely that the presence of balanced low order harmonics in leg voltages produces unbalanced phase voltage harmonics and consequently unbalanced phase current harmonics. By analysing the neutral point (common mode) voltage harmonics, imbalance in the phase voltage harmonics is explained. Analytical expressions for neutral point voltage harmonics and phase voltage harmonics are provided for asymmetrical machine configurations with a single neutral point having arbitrary numbers of sub-windings and sub-winding phases. Theoretical considerations are verified using simulations and experiments with asymmetrical twelve- and nine-phase loads with a single neutral point, respectively

A Frequency Multiplier Based on Time Recursive Processing

This paper describes a digital frequency multiplier for a pulse rate. The multiplier is based on the recursive processing of the input and output periods and their time differences. Special emphasis is devoted to the techniques which provide the development of multipliers based on this principle. The circuit is defined by two system parameters. One is the ratio of two clock frequencies and the other is a division factor of a binary counter. The realization of the circuit is described. The region of the system parameters for the stable circuit is presented. The different aspects of applications and limitations in realization of the circuit are considered. All mathematical analyses are made using a Z transform approach. It is shown that the circuit can be also used in tracking and prediction applications. Computer simulations are performed to prove the correctness of the math and the whole approach

Antineutrophil cytoplasmic antibody (ANCA)-associated autoimmune diseases induced by antithyroid drugs: comparison with idiopathic ANCA vasculitides

Clinical and serological profiles of idiopathic and drug-induced autoimmune diseases can be very similar. We compared data from idiopathic and antithyroid drug (ATD)-induced antineutrophil cytoplasmic antibody (ANCA)-positive patients. From 1993 to 2003, 2474 patients were tested for ANCA in the Laboratory for Allergy and Clinical Immunology in Belgrade. Out of 2474 patients, 72 (2.9%) were anti-proteinase 3 (PR3)- or anti-myeloperoxidase (MPO)-positive and their clinical and serological data were analyzed. The first group consisted of ANCA-associated idiopathic systemic vasculitis (ISV) diagnosed in 56/72 patients: 29 Wegener's granulomatosis (WG), 23 microscopic polyangiitis (MPA) and four Churg-Strauss syndrome. The second group consisted of 16/72 patients who became ANCA-positive during ATD therapy (12 receiving propylthiouracil and four receiving methimazole). We determined ANCA and antinuclear (ANA) antibodies by indirect immunofluorescence; PR3-ANCA, MPO-ANCA, anticardiolipin (aCL) and antihistone antibodies (AHA) by ELISA; and cryoglobulins by precipitation. Complement components C3 and C4, alpha-1 antitrypsin (α1 AT) and C reactive protein (CR-P) were measured by nephelometry. Renal lesions were present in 3/16 (18.8%) ATD-treated patients and in 42/56 (75%) ISV patients (p <0.001). Skin lesions occurred in 10/16 (62.5%) ATD-treated patients and 14/56 (25%) ISV patients (p <0.01). ATD-treated patients more frequently had MPO-ANCA, ANA, AHA, aCL, cryoglobulins and low C4 (p <0.01). ISV patients more frequently had low α1 AT (p = 0.059) and high CR-P (p <0.001). Of 16 ATD-treated patients, four had drug-induced ANCA vasculitis (three MPA and one WG), while 12 had lupus-like disease (LLD). Of 56 ISV patients, 13 died and eight developed terminal renal failure (TRF). There was no lethality in the ATD-treated group, but 1/16 with methimazole-induced MPA developed pulmonary-renal syndrome with progression to TRF. ANCA-positive ISV had a more severe course in comparison with ATD-induced ANCA-positive diseases. Clinically and serologically ANCA-positive ATD-treated patients can be divided into two groups: the first consisting of patients with drug-induced WG or MPA which resemble ISV and the second consisting of patients with LLD. Different serological profiles could help in the differential diagnosis and adequate therapeutic approach to ANCA-positive ATD-treated patients with symptoms of systemic disease

Arbitrary Power Sharing Among Three-Phase Winding Sets of Multiphase Machines

The paper develops a technique for arbitrary power sharing among three-phase winding sets of a multiphase generator. Multiple d-q modelling is commonly used when independent control of the winding sets is required. This work utilises instead the vector space decomposition modelling as the starting point and combines it with multiple d-q approach to preserve the advantages of the vector space decomposition, while still enabling independent control over each winding set. The power sharing is achieved by imposing appropriate x-y currents at the fundamental frequency, so that flux and average torque are not affected. The theory is developed initially for the nine-phase machine. A general expression for arbitrary current sharing is derived further for any multiphase machine with multiple three-phase windings. The obtained equations are valid for any possible machine topology (asymmetrical/ symmetrical, with single or multiple neutral points). The theory is validated experimentally using an asymmetrical nine-phase induction generator with indirect rotor field oriented control

The ASY-EOS experiment at GSI: investigating the symmetry energy at supra-saturation densities

The elliptic-flow ratio of neutrons with respect to protons in reactions of neutron rich heavy-ions systems at intermediate energies has been proposed as an observable sensitive to the strength of the symmetry term in the nuclear Equation Of State (EOS) at supra-saturation densities. The recent results obtained from the existing FOPI/LAND data for $^{197}$Au+$^{197}$Au collisions at 400 MeV/nucleon in comparison with the UrQMD model allowed a first estimate of the symmetry term of the EOS but suffer from a considerable statistical uncertainty. In order to obtain an improved data set for Au+Au collisions and to extend the study to other systems, a new experiment was carried out at the GSI laboratory by the ASY-EOS collaboration in May 2011.Comment: Talk given by P. Russotto at the 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS

Coulomb breakup of neutron-rich 29,30^{29,30}Na isotopes near the island of inversion

First results are reported on the ground state configurations of the neutron-rich $^{29,30}$Na isotopes, obtained via Coulomb dissociation (CD) measurements as a method of the direct probe. The invariant mass spectra of those nuclei have been obtained through measurement of the four-momentum of all decay products after Coulomb excitation on a $^{208}Pb$ target at energies of 400-430 MeV/nucleon using FRS-ALADIN-LAND setup at GSI, Darmstadt. Integrated Coulomb-dissociation cross-sections (CD) of 89 $(7)$ mb and 167 $(13)$ mb up to excitation energy of 10 MeV for one neutron removal from $^{29}$Na and $^{30}$Na respectively, have been extracted. The major part of one neutron removal, CD cross-sections of those nuclei populate core, in its' ground state. A comparison with the direct breakup model, suggests the predominant occupation of the valence neutron in the ground state of $^{29}$Na${(3/2^+)}$ and $^{30}$Na${(2^+)}$ is the $d$ orbital with small contribution in the $s$-orbital which are coupled with ground state of the core. The ground state configurations of these nuclei are as $^{28}$Na_{gs (1^+)\otimes\nu_{s,d} and $^{29}$Na$_{gs}(3/2^+)\otimes\nu_{ s,d}$, respectively. The ground state spin and parity of these nuclei, obtained from this experiment are in agreement with earlier reported values. The spectroscopic factors for the valence neutron occupying the $s$ and $d$ orbitals for these nuclei in the ground state have been extracted and reported for the first time. A comparison of the experimental findings with the shell model calculation using MCSM suggests a lower limit of around 4.3 MeV of the sd-pf shell gap in $^{30}$Na.Comment: Modified version of the manuscript is accepted for publication in Journal of Physics G, Jan., 201

A module-based analytical strategy to identify novel disease-associated genes shows an inhibitory role for interleukin 7 Receptor in allergic inflammation

<p>Abstract</p> <p>Background</p> <p>The identification of novel genes by high-throughput studies of complex diseases is complicated by the large number of potential genes. However, since disease-associated genes tend to interact, one solution is to arrange them in modules based on co-expression data and known gene interactions. The hypothesis of this study was that such a module could be a) found and validated in allergic disease and b) used to find and validate one ore more novel disease-associated genes.</p> <p>Results</p> <p>To test these hypotheses integrated analysis of a large number of gene expression microarray experiments from different forms of allergy was performed. This led to the identification of an experimentally validated reference gene that was used to construct a module of co-expressed and interacting genes. This module was validated in an independent material, by replicating the expression changes in allergen-challenged CD4⁺cells. Moreover, the changes were reversed following treatment with corticosteroids. The module contained several novel disease-associated genes, of which the one with the highest number of interactions with known disease genes, <it>IL7R</it>, was selected for further validation. The expression levels of <it>IL7R </it>in allergen challenged CD4⁺cells decreased following challenge but increased after treatment. This suggested an inhibitory role, which was confirmed by functional studies.</p> <p>Conclusion</p> <p>We propose that a module-based analytical strategy is generally applicable to find novel genes in complex diseases.</p

Shrinking-Hole Colloidal Lithography: Self-Aligned Nanofabrication of Complex Plasmonic Nanoantennas

Plasmonic nanoantennas create locally strongly enhanced electric fields in so-called hot spots. To place a relevant nanoobject with high accuracy in such a hot spot is crucial to fully capitalize on the potential of nanoantennas to control, detect, and enhance processes at the nanoscale. With state-of-the-art nanofabrication, in particular when several materials are to be used, small gaps between antenna elements are sought, and large surface areas are to be patterned, this is a grand challenge. Here we introduce self-aligned, bottom-up and self-assembly based Shrinking-Hole Colloidal Lithography, which provides (i) unique control of the size and position of subsequently deposited particles forming the nanoantenna itself, and (ii) allows delivery of nanoobjects consisting of a material of choice to the antenna hot spot, all in a single lithography step and, if desired, uniformly covering several square centimeters of surface. We illustrate the functionality of SHCL nanoantenna arrangements by (i) an optical hydrogen sensor exploiting the polarization dependent sensitivity of an Au-Pd nanoantenna ensemble; and (ii) single particle hydrogen sensing with an Au dimer nanoantenna with a small Pd nanoparticle in the hot spot

Interplane cross-saturation in multiphase machines

The use of electrical machines in electric vehicles and high-power drives frequently requires multiphase machines and multiphase inverters. While appropriate mathematical models under the linear magnetic conditions are readily available for multiphase machines, the same cannot be said for the models of the saturated multiphase machines. This paper examines the saturation in an asymmetrical six-phase induction machine under different supply conditions and addresses the applicability of the existing saturated three-phase machine models for representation of saturated multiphase machines. Specifically, the mutual coupling between different sequence planes in the vector space decomposed model under saturated conditions is analyzed. The paper relies on analytical considerations, finite element analysis and experimental results. It is shown that the saturation of the main flux path is influenced by the current components in the orthogonal (non-fundamental) sequence plane. This implies the need to develop new multiphase machine models which take this effect into account