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Stochastic models for sunshine duration and solar irradiation

Jain, P.K.; Lungu, E.M. (Elsevier Science Ltd: http://www.elsevier.com/wps/find/journaldescription.cws_home/969/description#description, NaN, 2002)

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Abstract:

Abstract Harmonic analysis of sunshine duration and solar irradiation measured at Sebele, Botswana is carried out. The data used consists of the monthly averages and the Julian-days averages of sunshine duration and solar irradiation sequences. This study involves splitting the time series into deterministic and stochastic components, and determining the proportion of the variance explained by each component. The stochastic component is analyzed for persistence using the Box and Jenkins technique. It is found that the stochastic component for monthly averages solar radiation series is best described by the second-order autoregressive Markov process, while that for Julian-days averages series has no memory.

URI:

http://hdl.handle.net/10311/138

Files in this item: 2

license.txt (1.998Kb)

Stocastic model ... and solar irradiation.pdf (614.0Kb)

The theory of attenuated total reflection by surface polaritons on corrugated semi-infinite media

Masale, M. (Elsevier Science Ltd. www.elsevier.com/locate/physb, February NaN, 2002)

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Abstract:

The experimental techniques of attenuated total reflection and grating-coupling were originally employed separately as probes for surface polaritons. However, as far back as the mid-1970s, some value was found in actually combining them into a single tool for probing elementary surface excitations. In this article, the theory of the two methods combined into one probe for surface polaritons is presented. The main results of the calculations, here, are the firstorder diffuse reflectivities, which arise due to the presence of a classical grating. For the ease of presentation, only a semi-infinite specimen is considered and the grating is thought to be deposited only on one interface. The discussion highlights the advantages the combined technique has over either of the two methods when each is employed on its own.

URI:

http://hdl.handle.net/10311/195

Files in this item: 2

license.txt (1.998Kb)

The theory of a ... ...semi-infinite media.pdf (1.164Mb)

The theory of attenuated total reflection by surface polaritons on one-sided corrugated thin films

Masale, M. (Elsevier Science Ltd. http://www.elsevier.com/wps/find/journaldescription.cws_home/505712/description#description, NaN, 2003)

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Abstract:

The experimental techniques of attenuated total reflection (ATR) and grating coupling were originally employed separately as probes for polaritons. The combined technique of these methods into a single probe is a very versatile tool for probing elementary surface excitations. A theoretical investigation of this single probe for surface polaritons, ATRgrating coupling, is undertaken. The emphasis is on the calculations of first-order diffuse reflectivities, which arise due to the presence of a classical grating. More specifically, the ATR set-up in the Otto configuration is considered and for ease of presentation of the results, a classical grating is thought to be deposited on only one interface of a surface-active thin-film specimen. The discussion highlights the advantages the combined technique has over either of the two methods when each is employed on its own.

URI:

http://hdl.handle.net/10311/233

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license.txt (1.998Kb)

The theory of a ... .corrugated thin films.pdf (1.140Mb)

Thermal annealing dependence of some physical propertiesof Bi-substituted Sn–Sb–Se glassy thin films

Ahmad, M.; Thangaraj, R.; Sathiaraj, T.S. (EDP Sciences, NaN, 2009)

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Abstract:

Bulk glasses of the Sn10Sb20−xBixSe70 (0 x 8) system were prepared by the conventional melt quenching technique. Thin films were prepared by the thermal evaporation technique on glass substrates. Appearance of some crystalline phases is observed from the X-ray diffractograms after heat treatment below the glass transition temperature for 1 h. Scanning electron microscopy studies also show the presence of microcrystalline phases in the amorphous matrix after annealing for 1 h. The effect of Bi concentration and heat treatment on the optical gap and activation energy for dark conductivity were also investigated for the pristine as well as annealed films. The results are discussed on the basis of models related to the presence of defect states in chalcogenide materials.

URI:

http://hdl.handle.net/10311/534

Files in this item: 1

Thermal annealing dependence.pdf (822.7Kb)

Type II superconducting disk in a spatially inhomogeneous applied magnetic field

Masale, M. (Elsevier Science Ltd. www.elsevier.com/locate/physc, January NaN, 2003)

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Abstract:

The problem of a type II superconducting disk in a spatially inhomogeneous magnetic field is considered. The aim of the investigations undertaken here is to evaluate the effects of the spatial inhomogeneity of the parallel component of the applied magnetic field on the nature of the superconducting nucleation of a short cylinder. Full numerical solutions of the linearized Ginzburg-Landau equation for the order parameter, taking into account only the parallel component of the field, are presented in the case of a solid disk;free-standing and in a metallic matrix. In the case of a mesoscopic system, only the limiting form of the critical temperature is obtained. The temperature-field (e-f) curves are characterized by flux-entry points at each of which the azimuthal quantum number decreases by unity. The quasi-period of the flux-entry points increases in f with the increasing strength of the spatial inhomogeneity of the applied field. The increased effect of coating the superconductor with a suitable normal metal leads to the well known suppression of the critical temperature as well as smoothing out of flux entries. It is predicted that the wiping out of surface nucleation is effected with relative ease when the applied magnetic field is uniform than when it posseses a degree of spatial inhomogeneity.

URI:

http://hdl.handle.net/10311/197

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license.txt (1.998Kb)

Type II superco ... in a spatially.........pdf (1.427Mb)

Understanding Nickel Thin Film crystallization using X-Ray Diffractometry

Otiti, T.; Ekosse, G-I.; Stephen, S.T. (Bioline International. http://www.ajol.info/journal_index.php?jid=90, June NaN, 2007)

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Abstract:

Normal, helical and zigzag deposited Ni films were produced by letting a vapour stream of source material impinge on Corning 1737 glass substrates at oblique incidence while rotating the substrate during deposition. Films produced by glancing angle deposition (GLAD) technique while rotating the substrate. The microstructures of these Ni films were studied using X-ray diffractometry technique. The X-ray diffraction (XRD) patterns depicted 100% and 42% relative intensity (RI) peaks identified for normal and helical deposited Ni films but none for the zigzag deposited Ni film. Higher degree of crystallinity of Ni was demonstrated by the helical thin film sample having 200 nm thickness (sample Ni40) compared to the normal thin film which had only the 100% RI peak defined. Should an application therefore require Ni thin films of high crystallinity, it would be the film prepared with helical microstructure of 200 nm thickness that will be employed.

URI:

http://hdl.handle.net/10311/353

Files in this item: 2

license.txt (1.998Kb)

Otiti_JASEM11_2007.pdf (451.5Kb)

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