Analytical Computation of End-Coil Leakage Inductance of Round-Rotor Synchronous Machines Field Winding

3noThe computation of end coil leakage inductances of electric machines is a challenging task due to the complicated leakage flux 3D distribution in the winding overhang region. In this paper the problem is addressed of computing the field circuit leakage inductance of round-rotor synchronous machines. The proposed method is fully analytical and descends from the symbolical solution of Neumann integrals applied to the computation of self and mutual inductances combined with the method of mirror images to account for core effects. With respect to existing analytical approaches, the methodology requires neither numerical integral solutions nor discretizing the end-coil geometry into small straight elements. The accuracy of the proposed technique for computing the mutual inductance between two single end turns is assessed against measurements on a dedicated experimental set-up. The extension of the method to the computation of the entire field-circuit end-coil leakage inductance is assessed by comparison with 3D finite element analysis (FEA).Pubblicato online nel settembre 2015 e pubblicato su carta nel febbraio 2016partially_openopenBortolozzi, Mauro; Tessarolo, Alberto; Bruzzese, ClaudioBortolozzi, Mauro; Tessarolo, Alberto; Bruzzese, Claudi

A New Method for Determining the Leakage Inductances of a Nine-Phase Synchronous Machine From No-Load and Short-Circuit Tests

The accurate determination of stator leakage inductances is presently an open issue in the analysis and testing of multi- phase electric machines. Calculation methods are available, which involve complicated and often poorly precise three-dimensional (3-D) analyses. Experimental determination techniques, using measurements on the wound stator with the rotor removed, are also possible, but quite impractical, as they need to be performed during machine manufacturing or require rotor withdrawal. In this paper, a new approach is proposed to determine all the stator self- and mutual leakage inductances of a nine-phase synchronous machine based on a minimal set (a couple) of magnetostatic finite- element (FE) simulations, and on the measurements taken during no-load and short-circuit routine tests. The procedure is applied to a wound-field salient pole nine-phase synchronous generator for validation, showing good accordance with the results obtained from measurements on the machine with the rotor removed. A discussion is also proposed on the possibility to extend the presented procedure to other multiphase topologie

Investigation into Multi-Layer Fractional-Slot Concentrated Windings with Unconventional Slot-Pole Combinations

Fractional-slot concentrated windings (FSCWs) are an attractive option for the design of synchronous permanent-magnet machines. It is commonly assumed in the existing literature that a symmetrical three-phase FSCW is feasible only on a condition that the number of slots Z is an integer multiple of three times the maximum common divisor between Z and the number of pole pairs p. Slot-pole combinations satisfying this rule can be defined conventionally, the others unconventionally. In contrast to the common belief, this paper shows that, using a multi-layer arrangement, it is possible to synthetize a symmetrical FSCW having unconventional slot-pole combinations. A general design methodology for this purpose is presented and validated by finite element analysis. The pros and contras of FSCWs with unconventional slot-pole combinations are examined. Finally, the application of an unconventional FSCW to a shipboard surface permanent-magnet machine prototype is presented to illustrate the possible practical convenience of this kind of winding and tests on the prototype are reported for experimental validation

Stability of Relativistic Matter with Magnetic Fields for Nuclear Charges up to the Critical Value

We give a proof of stability of relativistic matter with magnetic fields all the way up to the critical value of the nuclear charge $Z\alpha=2/\pi$.Comment: LaTeX2e, 12 page

Study of the skeketal muscle fibers in purebred and crossbred Landrace, Large White and Duroc swine

The muscle fibers of the external obturador (1) and long of the neck (2) were analyzed in 12 swine, three from each genetic group. Histoenzymological techniques were employed ( HE – hematoxilin – eosin, acid mAtpase – Adenosin triphosfate miofibrilar, pH 4,6 and NADH-Nicotinamide Adenine Dinucleotide Tetrazolium Reductase). This allowed to classify them to metabolism type (anaerobic or aerobic) and muscular contraction type (slow or fast). It was concluied that muscle 1 possesses more than 50% of fast twitch glycolitic fibers and muscle 2 more than 40% of slow twitch oxidative fibers. Both presented larger percentage of fast contraction fibers. Regarding metabolism, muscle 1 has a glycolitic (anaerobic) while 2 has an oxidative (aerobic) character

FEA-Assisted steady-state modelling of a spoke type IPM machine with enhanced flux weakening capability

Interior permanent magnet (IPM) machines with spoke-type design are possible candidates for various applications, including vehicle traction. One of their drawback is the high demagnetizing current required in the flux weakening region to let the motor achieve high speeds. This problem can be mitigated by equipping the motor with a mechanical devices consisting of mobile rotor yokes. These move radially by centrifugal force so as to reduce the air-gap flux at high speed with no need for demagnetizing current injection. This paper addresses the problem of modeling such IPM motor to study its steady-state behavior under different operating conditions, both in the full-flux and in the flux-weakening region of the speed range. The approach uses a limited set of non-linear finite element analysis to characterize the dependency of motor flux linkages on the stator currents and rotor position. Interpolating functions are then obtained to mathematically capture this dependency and plug it into the steady-state electromechanical equations of the motor. The effectiveness and accuracy of the method are assessed through on-load measurements taken on the modelled motor both in low and high speed operation

Electroforesis pattern of the proteins of swine skeletel muscles

Electroforesis of total protein samples from the external obturador and long muscle of the neck of Landrace, Large White, Duroc purebred and crossbred swine was conducted in polyacrilamide gel (PAGE) at 10%, to verify the existence of a specific eletroforesis pattern that might serve to control possible frauds in meats and processed pork products. The results confirmed the existence of a specific electrophoresis pattern for total proteins of skeletal muscle of swine, that is not altered in the various genetic groups and in the two muscles studied

Affioramento metallifero ad arseniati e solfati a debole radioattivit\ue0: Rio Spinal da Ciare (Cercivento-Udine)

Among the specimens of the mineralogical collection of Claudio Calligaris, entrusted to the Friulian Museum of Natural History after his untimely death, there are some samples from the Permian levels of the Val Gardena Sandstone, that present weak levels of radioactivity. The presence of radioactive minerals is relatively common in the outcrops of this formation throughout the Sudalpine area and for this reason, a few decades ago, some prospectings were carried out to verify its possible exploitation. In addition to the outcrop indicated in the Calligaris collection (Rio Minischitte, Paularo), similar levels have been identified in the area between Ravascletto and Cercivento: on these, more detailed research and some mineralogical analyses have been carried out on the collected samples: the presence of about thirty mineralogical species has been highlighted, none of which, however, is \u201cradioactive\u201d: as in other areas, the weak radioactivity detected comes from the adsorption of microscopic uranium particles onto organic matter (plant remains). Among the ascertained species, the following should be noted: anglesite, arsenolite, brochantite, chenevixite, cornwallite, devillin, langitis, mimetite, olivenitis, parnauite, richelsdorfite, scorodite, tennantite, tangdanite, tyrolite, zalesiite

Identification of the muscular proteins of pigs submitted to the eletroforesis in polyacrilamide gel with Sodium Dodecyl Sulfate (SDS)

Fragments of two pigs muscles of Landrace, Large White, Duroc purebred and crossbred, the eletroforesis was submitted in polyacrilamide gel with SDS, being objectified to verify there would be a specific pattern for pigs and to identify through the molecular weights, the main proteins. The results show that there would be a specific pattern for swine and they were identified miosina heavy chain, actina, troponina, tropomiosina and a light chain of miosina

TR-644 a novel potent tubulin binding agent induces impairment of endothelial cells function and inhibits angiogenesis.

TR-644 is a novel combretastatin A-4 (CA-4) analogue endowed with potent microtubule depolymerizing activity superior to that of the lead compound and it also has high affinity to colchicines binding site of tubulin. We tested TR-644 anti-angiogenic effects in human umbilical endothelial cells (HUVEC). It showed no significant effects on the growth of HUVEC cells at concentrations below 1,000 nM, but at much lower concentrations (10-100 nM) it induced inhibition of capillary tube formation, inhibition of endothelial cell migration and affected endothelial cell morphology as demonstrated by the disruption of the microtubule network. TR-644 also increased permeability of HUVEC cells in a time dependent manner. The molecular mechanism for the anti-vascular activity of TR-644 was investigated in detail. TR-644 caused G2/M arrest in endothelial cells and this effect correlated with downregulation of the expression of Cdc25C and Cdc2Tyr15. Moreover TR-644 inhibited VEGF-induced phosphorylation of VE-cadherin but did not prevent the VEGF-induced phosphorylation of FAK. In chick chorioallantoic membrane in vivo assay, TR-644 (0.1-1.0 pmol/egg) efficiently counteracted the strong angiogenic response induced by FGF. Also CA-4, used as reference compound, caused an antagonistic effect, but in contrast, it induced per se, a remarkable angiogenic response probably due to an inflammatory reaction in the site of treatment. In a mice allogenic tumor model, immunohistochemical staining of tumors with anti-CD31 antibody showed that TR-644 significantly reduced the number of vessel, after 24 h from the administration of a single dose (30 mg/Kg)