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A method is presented for calculating the electromagnetic forces on the end windings of turbine generators for both the steady state and transient modes of operation. Part 1 of this paper deals with the basic concepts of the force calculation and gives several examples of steady state forces and how they vary with load and power factor. PartII deals with several types of transient operation. The currents and fields which these transients produce are discussed and forces are found for various cases such as short circuits, synchronizing out of phase and transmission line switching.

The paper describes a two dimensional numerical model for analysis of the local and integral characteristics of linear electromagnetic pumps, such as magnetic field distribution, pressure developed, amplitude of pressure pulsation with double supply frequency and distribution of liquid metal velocity over the azimuth. Numerical results are compared with experimental ones.

Abstract Thin films of vanadium oxide were deposited on glass substrates at 450 o C by atmospheric pressure chemical vapour deposition. The effect of the vanadium tetrachloride to water precursor ratio on the structural and morphological properties of the films was investigated. The water concentration was observed to strongly affect the vanadium oxidation state and the morphological characteristics of the films. The importance of achieving single-phase of a particular oxidation state towards the improvement of the electrochemical performance of thin films grown by atmospheric pressure CVD is highlighted.

Silver-based Al-doped ZnO (AZO) multilayer coatings were prepared on glass by e-beam evaporation techniques. Optimization of the deposition conditions of both AZO and Ag layers were performed for better electrical and optical properties. The properties of the multilayers were affected by the deposition process of both AZO and Ag layers. The best multilayer coatings exhibit low sheet resistance of 5.34 Ω/sq and transmittance of more than 85%. The coatings have satisfactory properties of low resistance and high transmittance for application as transparent conductive electrodes.

AbstractThis paper presents an understanding of the fundamental carrier transport mechanism in hydrogenated amorphous silicon (a‐Si:H)‐based n/p junctions. These n/p junctions are, then, used as tunneling and recombination junctions (TRJ) in tandem solar cells, which were constructed by stacking the a‐Si:H‐based solar cell on the heterojunction with intrinsic thin layer (HIT) cell. First, the effect of activation energy (Ea) and Urbach parameter (Eu) of n‐type hydrogenated amorphous silicon (a‐Si:H(n)) on current transport in an a‐Si:H‐based n/p TRJ has been investigated. The photoluminescence spectra and temperature‐dependent current–voltage characteristics in dark condition indicates that the tunneling is the dominant carrier transport mechanism in our a‐Si:H‐based n/p‐type TRJ. The fabrication of a tandem cell structure consists of an a‐Si:H‐based top cell and an HIT‐type bottom cell with the a‐Si:H‐based n/p junction developed as a TRJ in between. The development of a‐Si:H‐based n/p junction as a TRJ leads to an improved a‐Si:H/HIT‐type tandem cell with a better open circuit voltage (Voc), fill factor (FF), and efficiency. The improvements in the cell performance was attributed to the wider band‐tail states in the a‐Si:H(n) layer that helps to an enhanced tunneling and recombination process in the TRJ. The best photovoltage parameters of the tandem cell were found to be Voc = 1430 mV, short circuit current density = 10.51 mA/cm2, FF = 0.65, and efficiency = 9.75%. Copyright © 2015 John Wiley & Sons, Ltd.

Abstract An alkaline earth boro-aluminosilicate glass (Eagle XG), a soda-lime glass, and a light-weight polyethylene-terephthalate (PET) foil, used as typical substrates for photovoltaics, were treated by an energetic proton beam (3 MeV, dose 106–107 Gy) corresponding to approx. 30 years of operation at low Earth orbit. Properties of the irradiated substrates were characterized by atomic force microscopy, optical absorption, optical diffuse reflectance, Raman spectroscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and terahertz (THz) spectroscopy. Minimal changes of optical and morphological properties are detected on the bare Eagle XG glass, whereas the bare PET foil exhibits pronounced increase in optical absorption, generation of photoluminescence, as well as mechanical bending. On the other hand, the identical substrates coated with Indium-tin-oxide (ITO), which is a typical material for transparent electrodes in photovoltaics, exhibit significantly higher resistance to the modifications by protons while ITO structural and electronic properties remain unchanged. The experimental results are discussed considering a potential application of these materials for missions in space.

Abstract Formation mechanism of CIS thin films by selenization of sputter deposited CuIn precursor with Se vapor was investigated by ex-situ and in-situ phase analysis tools. Precursor films were composed of In, CuIn and Cu2In compounds, and their relative fractions were systematically changed with Cu/In ratios. Those films were found to have a double layered structure with nearly pure In particles (top layer) placed on the flat Cu-rich bottom layer, and the morphologies were also significantly affected by Cu/In ratio. At the initial stage of selenization, the outer In-rich layer reacted with Se vapor to form In–Se binary, which is the first selenide phase appeared, and inner Cu-rich phases acted as a Cu source to supply Cu to outer In–Se phase to form ordered vacancy compounds (OVC). As these reactions continues, in conjunction with Se incorporation into inner Cu-rich region, the films gradually changes from OVC to α-CIS, reflecting that the formation route of CIS is closely related to the elemental and phase distribution in precursor films. Selenized CIS films were further processed to fabricate CIS thin film solar cells, resulting in the best cell efficiency of 10.44%.

CdTe‐based thin film solar cell has been modeled and enumerated with a thin CuInTe2 (CIT) current booster layer. CdTe‐based n‐CdS/p‐CdTe/p+‐CIT/p++‐WSe2 heterojunction device is evaluated for the highest performance. It is revealed that physical parameters such as thickness, doping, and defects of the CIT layer have a significant influence on the performance of the CdTe solar cell. The device shows an efficiency of 37.46% with an open‐circuit voltage, VOC, of 1.102 V, short‐circuit current density, JSC, of 38.50 mA cm−2, and fill factor, FF, of 88.30%. The use of the photon recycling technique with a Bragg reflector with 98% back and 95% front reflectance only provides an efficiency of ≈44.3% with a current of 45.4 mA cm−2. These findings are very hopeful for the production of efficient CdTe solar cells in the near future.

Abstract Radioactive liquid waste is often stored in a large capacity (150 m 3 ) horizontal cylindrical tanks. It is necessary to keep the contents of the tank agitated to prevent the settling of fine solids in the tank. In extreme cases, solids settled at the tank base may invoke the system malfunction. This paper deals with the Computational Fluid Dynamic (CFD) modeling of the agitation mechanism considering the turbulent dispersion effects. The simulations are conducted on a standard tank geometry to arrive the optimum jet velocity required to suspend the settled solid particles thoroughly. The distribution of volume phase fraction, velocity magnitude, turbulence kinetic energy (TKE) and eddy dissipation of each phase for different inlet jet velocities (v = 10–25 m / s ) have been presented. The spatial variation of these quantities are measured at three different planes in the vessel mainly in the vicinity of the nozzle exit. The results indicate that the jet velocity is a significant parameter that influences the particle suspension. Parametric studies have also been carried out for four different particle sizes, viz. d p = 5, 10, 50 and 100 μ m . The present study revealed that, for the range of parameters covered, the smallest ( d p = 5 μ m ) and the largest ( d p = 100 μ m ) particle sizes has least effect in terms of solids suspension.