Magnetic equivalent circuit model of surface type fractional-slot permanent magnet synchronous generator

Design of permanent magnet synchronous machines becomes more of an issue for all systems lately. There are many parameters that have influence for machine design. Each parameter should have optimized and their effects on the system should be determined. Any desired pre-design have been done for machine design except a few paper and it only showed by of Finite element analysis (FEA). In this article, analytical method is used in permanent magnet synchronous machine design and the effects of geometric on the performance of machine are presented. Magnetic equivalent circuit (MEC) model is used as numeric method. It is observed that the proposed MEC model is pertinent to Speed PC-BDC model and FEA. Besides proposed MEC model provides to calculate performances of the machines which have the desirable slot/pole combinations correctly. Proposed model is applied on the recently increased fractional slot direct drive synchronous generators

Genome-scale reconstruction of metabolic network for a halophilic extremophile, Chromohalobacter salexigens DSM 3043

<p>Abstract</p> <p>Background</p> <p><it>Chromohalobacter salexigens </it>(formerly <it>Halomonas elongata </it>DSM 3043) is a halophilic extremophile with a very broad salinity range and is used as a model organism to elucidate prokaryotic osmoadaptation due to its strong euryhaline phenotype.</p> <p>Results</p> <p><it>C. salexigens </it>DSM 3043's metabolism was reconstructed based on genomic, biochemical and physiological information via a non-automated but iterative process. This manually-curated reconstruction accounts for 584 genes, 1386 reactions, and 1411 metabolites. By using flux balance analysis, the model was extensively validated against literature data on the <it>C. salexigens </it>phenotypic features, the transport and use of different substrates for growth as well as against experimental observations on the uptake and accumulation of industrially important organic osmolytes, ectoine, betaine, and its precursor choline, which play important roles in the adaptive response to osmotic stress.</p> <p>Conclusions</p> <p>This work presents the first comprehensive genome-scale metabolic model of a halophilic bacterium. Being a useful guide for identification and filling of knowledge gaps, the reconstructed metabolic network <it>i</it>OA584 will accelerate the research on halophilic bacteria towards application of systems biology approaches and design of metabolic engineering strategies.</p

Dynamics and torque analysis of permanent magnet synchronous generator with soft magnetic composite material

Usage of permanent magnet synchronous machines (PMSM) in wind turbines recently became more of an issue. The development in permanent magnet synchronous machines through the latest technologies, especially about machine design, increases the importance of those machines. Developments in materials technology implement the development of cost effective and profitable products on electric machines and bring simplicity in design. Especially Soft Magnetic Composite (SMC) materials became to be used recently in machine designs due to its advantages such as low costs and providing 3D flux paths. In this work the 2D magnetic equivalent circuit (MEC) of PMSM machine, which includes SMC in its stator part, was composed and stated magnetic equivalent circuit was verified by finite element method. Also torque and radial forces of PMSM were calculated as well. When SMC materials are used in electric machines, flux flows in 3D. 3D finite element method takes quite long time. Due to 2D MEC analysis that was used in our work, the analysis periods become remarkably shorter. Besides the proposed MEC model enables to calculate performances of the machines, which have the desirable slot/pole combinations, correctly. Proposed model is applied on the recently improved fractional slot direct drive synchronous generators

Magnetic and electrical properties of NdNiSn

Magnetization and resistivity measurements have been carried out on the equiatomic ternary compound NdNiSn in the temperature range 2–200 K. The compound crystallizes in the orthorhombic CeNiSn-type structure with space group Pna21. Magnetic susceptibility shows a distinct feature at TN=3 K (Néel temperature), typical of a phase transition from an antiferromagnetic to paramagnetic state. In the paramagnetic regime, the magnetic susceptibility obeys Curie–Weiss behavior yielding an effective magnetic moment μeff=3.32μB at lower temperatures, and 3.88 μB at higher temperatures. The reduction in the magnetic moment at lower temperatures is attributed to a crystalline electric field (CEF) effect, while the slight excess of magnetic moment at high temperatures compared to that of the free Nd3+ ion (3.62 μB) indicates that only a very small magnetic moment, at most 0.3 μB, is induced at the Ni sites. The electrical resistivity exhibits metallic behavior and no anomaly is observed at the respective Néel temperature. Analysis of the resistivity data in terms of crystalline electric fields including s–d electron scattering reveals that the ground magnetic state for the Nd3+ ions is a doublet of J=±5/2 states, with a first exited doublet of J=±7/2 states having an energy splitting of 56 K, with the next exited multiplet 139 K above the ground levels. These results are in fairly good agreement with those reported in the literature based on magnetic susceptibility and heat capacity measurements

Effect of exchange bias on the electrical resistivity of Pd doped NiMn thin films: Two-Channel Kondo system

Electrical resistivity measurements have been carried out for both flash-evaporated reentrant spin glasses (RSGs) (Ni76−xPdx)Mn24 and Ni74.5Mn23.5Pd2, as well as Ni75Mn23Pd2, a pure SG. These measurements were carried out at temperatures down to 4K. We observed a very deep resistivity minimum at about 75K for Ni74Mn24Pd2. It was found previously [Öner et al., J. Appl. Phys.89, 7044 (2001)] that this sample shows the largest coercivity and exchange unidirectional anisotropy among these films. In addition, magnetization measurements show that this takes place just on the border of the RSG such that it could be handled as a superparamagnetic sample. Previously it was assumed that the exchange bias created in the sample between the domains plays the dominant role in the resistivity minimum. On the other hand, in order to account for the temperature dependence of the resistivity below the minimum we have analyzed these data using the Kondo, two-channel Kondo, weak localization, and Cochrane models for structural disorder based on the Anderson mechanism. We have deduced that the two-channel Kondomodel gives the best agreement with the data; a logarithmic temperature dependence Δρ(T)=βlog10(T∕TK), was observed at the temperatures below Tf accompanied by a resistivity behavior Δρ(T)=ρ0m(0)(1−αT1∕2), at lower temperatures. All parameters deduced from the fitting correlate consistently with the strength of the exchange anisotropy and coercivity in the RSG films, and thus provide a separate measure of the presence of antiferromagnetically coupled domains in these materials

Magnetic equivalent circuit model of surface type fractional-slot permanent magnet synchronous generator

Design of permanent magnet synchronous machines becomes more of an issue for all systems lately. There are many parameters that have influence for machine design. Each parameter should have optimized and their effects on the system should be determined. Any desired pre-design have been done for machine design except a few paper and it only showed by of Finite element analysis (FEA). In this article, analytical method is used in permanent magnet synchronous machine design and the effects of geometric on the performance of machine are presented. Magnetic equivalent circuit (MEC) model is used as numeric method. It is observed that the proposed MEC model is pertinent to Speed PC-BDC model and FEA. Besides proposed MEC model provides to calculate performances of the machines which have the desirable slot/pole combinations correctly. Proposed model is applied on the recently increased fractional slot direct drive synchronous generators