| 739201. |
- Joshi, S. V., et al.
(författare)
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Plasma spraying of an indigenous yttria stabilized zirconia powder prepared by the sol-gel technique
- 1993
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Ingår i: Bulletin of Materials Science. - : Springer India. ; 16:1, s. 19-28
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Tidskriftsartikel (refereegranskat)abstract
- An indigenous sol-gel derived yttria-partially stabilized zirconia (Y-PSZ) powder has been characterized and its suitability for plasma spraying applications evaluated. The powder, determined to have about 5·1% yttria content, predominantly consisted of spherical particles with an average equivalent particle diameter close to 25 μm. Furthermore, it was found that the powder did not contain any particles >50 μm, which is considered the ideal upper size limit for spray-grade ceramic powders in order to ensure complete melting during spraying. The sol-gel produced powder exhibited good flow characteristics and the plasma sprayed coatings developed using this powder were also found to have excellent thermal shock resistance. The corresponding results obtained using an imported Y-PSZ powder are also presented for the purpose of comparison. © 1993 Indian Academy of Sciences.
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| 739202. |
- Joshi, S. V., et al.
(författare)
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Plasma spraying of biologically derived hydroxyapatite on implantable materials
- 1993
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Ingår i: Journal of Materials Science: Materials in Medicine. - : Kluwer Academic Publishers. ; 4:3, s. 251-255
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Tidskriftsartikel (refereegranskat)abstract
- Plasma spraying of hydroxyapatite (HA) coatings on human implants is considered to provide a promising means of enhancing their biocompatibility and improving tissue growth. This paper briefly describes a method of extracting HA powder from a biological source, namely human teeth. The physical and chemical characteristics of the derived powder are studied and the suitability of this powder for plasma spraying applications is ascertained. The deposited coatings are found to retain the chemistry characteristic of the apatite. Typical results of metallographic and scanning electron microscopy (SEM) studies and hardness measurements on the sprayed HA coatings are presented. © 1993 Chapman & Hall.
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| 739203. |
- Joshi, Shrikant V., 1960-, et al.
(författare)
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Plasma spraying of ceramic powders produced by the sol-gel technique
- 1992
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Ingår i: Metals Materials and Processes. - 0970-423X. ; 4:1, s. 33-42
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Tidskriftsartikel (refereegranskat)abstract
- The development of plasma-sprayed protective layers to enhance the surface properties of critical engineering components represents one of the most promising achievements of materials technology in recent times. The important aspects associated with plasma spraying of ceramic powders are discussed and the influence of the powder characteristics on the quality of sprayed coatings is highlighted. The advantages of the sol-gel technique for preparing spray grade powders are briefly outlined. The sol-gel synthesis of a Yttria-stabilized-zirconia powder is discussed as a case study. Results of powder characterization studies and evaluation of its plasma sprayed coating are also presented.
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| 739204. |
- Joshi, S. V.
(författare)
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Plasma spraying of Wc-Co part I : Theoretical investigation of particle heating and acceleration during spraying
- 1993
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Ingår i: Journal of Thermal Spray Technology. - : Springer-Verlag. ; 2:2, s. 127-130
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Tidskriftsartikel (refereegranskat)abstract
- Plasma-sprayed WC-Co coatings are used extensively in a variety of wear-resistant applications. The quality of these sprayed coatings depends greatly on the temperature and velocity of the powder particles impacting the substrate. Because it is both expensive and difficult to experimentally determine these particle parameters, the present study deals with a theoretical investigation of particle heatup and acceleration during plasma spraying of WC-Co based on a recently developed model. The effect of WC-Co particle size on the evolution of particle temperature and velocity is examined through calculations performed under typical spraying conditions. The implications of the powder particles, assuming an off-axis trajectory during their traverse through the plasma flame, are also discussed. © 1993 ASM International.
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| 739205. |
- Joshi, S. V., et al.
(författare)
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Prediction of in-flight particle parameters during plasma spraying of ceramic powders
- 1992
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Ingår i: Materials Science and Technology. ; 8:6, s. 481-488
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Tidskriftsartikel (refereegranskat)abstract
- A theoretical prediction model is presented to estimate the in-flight velocity, temperature, and size of a ceramic particle traversing through a plasma flame. The model accounts for the various phenomena that can influence the transport rate calculations in plasma spraying operations, which typically involve very fine particles (<50 μm) subjected to an extremely non-isothermal environment. The mathematical formulation simultaneously considers internal heat conduction in particles, accounts for the steep temperature gradients that prevail in plasma-particle systems, and incorporates the Knudsen discontinuum effects on both heat and momentum transfer. The significance of these factors is illustrated through some example calculations performed under typical plasma spraying conditions. Comparison with experimental data reveals that the present method, although simple and easy to use, enables accurate predictions to be made and can be a very useful tool in the model assisted development of various plasma-particle processing systems.
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| 739206. |
- Joshi, S. V., et al.
(författare)
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Quantitative performance evaluation of a wind turbine generator cluster using statistical techniques
- 2014
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Ingår i: Energy Procedia. - : Elsevier. - 1876-6102. ; 54, s. 211-220
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Tidskriftsartikel (refereegranskat)abstract
- This report dissects the analysis of annual performance of a cluster of wind turbine generators operated by Suzlon Energy Limited to troubleshoot shortfalls in the predicted generation of individual machines for the fiscal year of 2011-12. The first phase involved an estimation of the annual energy production using wind resource assessment on the commercial software Wind Atlas, Analysis and Application Program (WAsP). Comparison of the Annual Energy Production (AEP) with direct extrapolation of monthly generation to centum machine and grid availability highlighted negative inconsistency between the two in the case of five machines. Detailed study of their data histories indicated the reason to be coarse extrapolation and generation curtailment, although the latter is a minor contributor. The second phase consists of quantification of these losses for the concerned machines using statistical extrapolation and a variety of data approaches. A qualitative comparison of the methods is presented based on accuracy and utility. It is concluded that correlation of average hub-height wind velocities with the concerned machine's generation yields the most reliable and professionally useful results. Also, the advantages and shortcomings of the other methods have been discussed.
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| 739207. |
- Joshi, Shrikant V., 1960-
(författare)
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Special Issue : Advances in Thermal Spray Technology
- 2020
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Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 13:16
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Tidskriftsartikel (refereegranskat)abstract
- Coatings deposited utilizing different thermal spray variants have been widely used for diverse industrial applications [...].
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| 739208. |
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| 739209. |
- Joshi, S. V., et al.
(författare)
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The integral mean diffusivity for particle-gas mass transfer calculations under thermal plasma conditions
- 1985
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Ingår i: Plasma Chemistry and Plasma Processing. - : Kluwer Academic Publishers-Plenum Publishers. ; 5:2, s. 143-161
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Tidskriftsartikel (refereegranskat)abstract
- A new integral mean diffusivity is proposed for the calculation of the mass transfer rate around a small particle immersed in a thermal plasma gas. Analogous to the integral mean thermal conductivity widely used for the corresponding heat transfer calculations, the integral mean diffusivity greatly facilitates the use of the convenient isothermal correlation, Sh=2.0, for the gas-particle mass transfer calculations. The calculation method accounts for both ordinary molecular diffusion and thermal diffusion. The latter has been found to play a significant role under thermal plasma conditions. The use of the integral mean diffusivity is illustrated with an example calculation on an Ar-He plasma system. © 1985 Plenum Publishing Corporation.
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| 739210. |
- Joshi, Somya, et al.
(författare)
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Whose Future Is It Anyway? : Limits within Policy Modeling
- 2016
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Ingår i: LIMITS '16. - New York, NY, USA : ACM Digital Library. - 9781450342605
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Konferensbidrag (refereegranskat)abstract
- In the age of Big Open Linked Data (BOLD), we inhabit a landscape where future scenarios are imagined, modeled, planned for and embedded in policy. Between the euphoric techno-utopian rhetoric of the boundless potential of BOLD innovations and the dystopian view of the dangers of such innovations (e.g. ubiquitous surveillance etc.), this paper offers a critical understanding of the boundaries that are traversed by the implementation of BOLD within policy modeling. We examine BOLD as a tool for imagining futures, for reducing uncertainties, for providing legitimacy and for concentrating power. In doing so we further develop the LIMITs community’s conceptualization of the societal limitations on computing, with specific reference to the assumptions, interpretations and trust that we place in these models when making socio-environmental policy decisions. We use an illustrative case of policy modeling, which provides a much-needed critical discussion of the inherent limitations and risks as well as the promises that are offered by BOLD.
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