Design and analysis of a claw pole permanent magnet motor with molded soft magnetic composite core

Soft magnetic composite (SMC) materials and SMC electromagnetic devices have undergone substantial development in the past decade. Much work has been conducted on designing and prototyping various types of electrical machine. However, the iron cores were often made by cutting existing SMC preforms that were formed by compacting SMC powder in simple cylinder or bar-shape molds, and the magnetic properties of the cores may deteriorate significantly during the cutting process. To investigate "industry production-ready" products, this paper presents the design and analysis of a claw-pole permanent magnet (PM) motor with a molded SMC core of low mass density to replace the existing induction motor in a dishwasher pump. The magnetic properties of the molded SMC core are measured and utilized in the motor design and analysis. Finite element analysis (FEA) of magnetic field is carried out to accurately determine key motor parameters, and an improved phase variable model is applied to predict the motor performance. Both parameter computation and performance prediction are validated by the experimental results on the prototype. © 2009 IEEE

Electromagnetic optimal design of a linear induction motor in linear metro

An improved T-model equivalent circuit of a single-sided linear induction machine (SLIM) is proposed. The analysis utilizes a set of one-dimensional air gap flux linkage equations. The model takes longitudinal end and transversal edge effects into consideration. These have to account for primary terminal half-filled slots, secondary back-iron saturation and skin effect in the secondary conducting sheet. In the circuit, several coefficients are obtained by use of the dummy electric potential method in conjunction with consideration of the complex power equivalence between the primary and secondary sides. The coefficients derived include the longitudinal end effect coefficients K r and Kx, transversal edge effect coefficients C r and Cx, and skin effect coefficient Kf. The accuracy of the T-model is validated using comparison to a set of measured data under constant current - constant frequency conditions. These were taken from the Intermediate Capacity Transit System (ICTS) in Canada. An optimal design scheme for the SLIM is addressed. The application used for the optimization is a prototype propulsion system in a high temperature superconducting (HTS) maglev drive. The efficiency and primary weight are chosen as optimal objective functions while the thrust, power factor and other performance indexes are calculated. © 2010 IEEE

An improved series equivalent circuit of a single-sided linear induction motor

The derivation of the equivalent circuit for a single-sided linear induction motor (SLIM) is not straightforward. Especially if it includes longitudinal end effects from the cut-open primary magnetic path, transverse edge effects from the differing widths between the primary lamination and secondary sheet, and half filled primary slots. This paper proposes an improved series equivalent circuit for this machine. The longitudinal end effects are estimated using three different impedances representing the normal, forwards and backwards flux density waves in the air-gap. The transverse edge effects accounted for with a correction coefficient Kt and an air-gap flux density correction coefficient Kb. Using the series circuit, the performance of the SLIM was assessed in a similar manner to a rotating induction machine. A 4 kW SLIM prototype was tested which validated the simulation technique ©2009 IEEE

Spatial and temporal variations of aerosols around Beijing in summer 2006: Model evaluation and source apportionment

Regional aerosol model calculations were made using the Weather Research and Forecasting (WRF)-Community Multiscale Air Quality (CMAQ) and WRF-chem models to study spatial and temporal variations of aerosols around Beijing, China, in the summer of 2006, when the Campaigns of Air Quality Research in Beijing and Surrounding Region 2006 (CAREBeijing) intensive campaign was conducted. Model calculations captured temporal variations of primary (such as elemental carbon. (EC)) and secondary (such as sulfate) aerosols observed in and around Beijing. The spatial distributions of aerosol optical depth observed by the MODTS satellite sensors were also reproduced over northeast China. Model calculations showed distinct differences in spatial distributions between primary and secondary aerosols in association with synoptic-scale meteorology. Secondary aerosols increased in air around Beijing on a scale of about 1000 × 1000 km2 under an anticyclonic pressure system. This air mass was transported northward from the high anthropogenic emission area extending south of Beijing with continuous photochemical production. Subsequent cold front passage brought clean air from the north, and polluted air around Beijing was swept to the south of Beijing. This cycle was repeated about once a week and was found to be responsible for observed enhancements/reductions of aerosols at the intensive measurement sites. In contrast to secondary aerosols, the spatial distributions of primary aerosols (EC) reflected those of emissions, resulting in only slight variability despite the changes in synopticscale meteorology. In accordance with these results, source apportionment simulations revealed that primary aerosols around Beijing were controlled by emissions within 100 km around Beijing within the preceding 24 h, while emissions as far as 500 km and within the preceding 3 days were found to affect secondary aerosols. Copyright 2009 by the American Geophysical Union

Violet electroluminescence of AlInGaN-InGaN multiquantum-well light-emitting diodes: Quantum-confined stark effect and heating effect

Electroluminescence (EL) from AlInGaN-InGaN multiquantum-well violet light-emitting diodes is investigated as a function of forward bias. Two distinct regimes have been identified: 1) quantum-confined Stark effect at low and moderately high forward biases; 2) heating effect at high biases. In the different regimes, the low-temperature EL spectra exhibit different spectral features which are discussed in detail. © 2007 IEEE.published_or_final_versio

Data Fusion of Objects Using Techniques Such as Laser Scanning, Structured Light and Photogrammetry for Cultural Heritage Applications

In this paper we present a semi-automatic 2D-3D local registration pipeline capable of coloring 3D models obtained from 3D scanners by using uncalibrated images. The proposed pipeline exploits the Structure from Motion (SfM) technique in order to reconstruct a sparse representation of the 3D object and obtain the camera parameters from image feature matches. We then coarsely register the reconstructed 3D model to the scanned one through the Scale Iterative Closest Point (SICP) algorithm. SICP provides the global scale, rotation and translation parameters, using minimal manual user intervention. In the final processing stage, a local registration refinement algorithm optimizes the color projection of the aligned photos on the 3D object removing the blurring/ghosting artefacts introduced due to small inaccuracies during the registration. The proposed pipeline is capable of handling real world cases with a range of characteristics from objects with low level geometric features to complex ones

Quantum dissipation and broadening mechanisms due to electron-phonon interactions in self-formed InGaN quantum dots

Quantum dissipation and broadening mechanisms in Si-doped InGaN quantum dots are studied via the photoluminescence technique. It is found that the dissipative thermal bath that embeds the quantum dots plays an important role in the photon emission processes. Observed spontaneous emission spectra are modeled with the multimode Brownian oscillator model achieving an excellent agreement between experiment and theory for a wide temperature range. The dimensionless Huang-Rhys factor characterizing the strength of electron-LO-phonon coupling and damping constant accounting for the LO-phonon-bath interaction strength are found to be ∼0.2 and 200 cm-1, respectively, for the InGaN QDs. © 2006 American Institute of Physics.published_or_final_versio

Mitochondrial Ca(2+) uptake by the voltage-dependent anion channel 2 regulates cardiac rhythmicity.

Tightly regulated Ca(2+) homeostasis is a prerequisite for proper cardiac function. To dissect the regulatory network of cardiac Ca(2+) handling, we performed a chemical suppressor screen on zebrafish tremblor embryos, which suffer from Ca(2+) extrusion defects. Efsevin was identified based on its potent activity to restore coordinated contractions in tremblor. We show that efsevin binds to VDAC2, potentiates mitochondrial Ca(2+) uptake and accelerates the transfer of Ca(2+) from intracellular stores into mitochondria. In cardiomyocytes, efsevin restricts the temporal and spatial boundaries of Ca(2+) sparks and thereby inhibits Ca(2+) overload-induced erratic Ca(2+) waves and irregular contractions. We further show that overexpression of VDAC2 recapitulates the suppressive effect of efsevin on tremblor embryos whereas VDAC2 deficiency attenuates efsevin\u27s rescue effect and that VDAC2 functions synergistically with MCU to suppress cardiac fibrillation in tremblor. Together, these findings demonstrate a critical modulatory role for VDAC2-dependent mitochondrial Ca(2+) uptake in the regulation of cardiac rhythmicity

Effect of nickel on the microstructure and mechanical property of die-cast Al–Mg–Si–Mn alloy

The effect of nickel on the microstructure and mechanical properties of a die-cast Al–Mg–Si–Mn alloy has been investigated. The results show that the presence of Ni in the alloy promotes the formation of Ni-rich intermetallics. These occur consistently during solidification in the die-cast Al–Mg–Si–Mn alloy across different levels of Ni content. The Ni-rich intermetallics exhibit dendritic morphology during the primary solidification and lamellar morphology during the eutectic solidification stage. Ni was found to be always associated with iron forming AlFeMnSiNi intermetallics, and no Al3Ni intermetallic was observed when Ni concentrations were up to 2.06 wt% in the alloy. Although with different morphologies, the Ni-rich intermetallics were identified as the same AlFeMnSiNi phase bearing a typical composition of Al[100–140](Fe,Mn)[2–7]SiNi[4–9]. With increasing Ni content, the spacing of the α-Al–Mg2Si eutectic phase was enlarged in the Al–Mg–Si–Mn alloy. The addition of Ni to the alloy resulted in a slight increase in the yield strength, but a significant decrease in the elongation. The ultimate tensile strength (UTS) increased slightly from 300 to 320 MPa when a small amount (e.g. 0.16 wt%) of Ni was added to the alloy, but further increase of the Ni content resulted in a decrease of the UTS.The Engineering and Physical Sciences Research Council (EPSRC), Technology Strategy Board (TSB) and Jaguar Land Rover (JLR) in the United Kingdom