Papers by Shailendra oree
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
High Pressure Research, 2001
We report the use ofmicrowave-hydrothermal processing to synthesire various ceramic powders. Micr... more We report the use ofmicrowave-hydrothermal processing to synthesire various ceramic powders. Microwave-hydrothermal processing is compared with conventional hydro thennal processing in the crystallisation of MoO 2 • The presence of microwave fi eld leads to accelerated kinetics of crystallization of the finely divided molybdenum dioxide particles. Existing microwave heated pressure vessels for chemical synthesis cannot be used above 250 MPa and 270 °C because they contain parts made of polymeric materials. The objective ofthis work is to associate a microwave source to a high pressure vesse! in a way such that it might be used to carry out reactions in acqueous media at pressures around IOOMPa and temperatures above the critical point of water.
AEÜ. International journal of electronics and communications, Apr 1, 2024
2017 IEEE Radio and Antenna Days of the Indian Ocean (RADIO), 2017
The complex relative permittivity ε'<inf>r</inf> — jε"<inf>req</inf... more The complex relative permittivity ε'<inf>r</inf> — jε"<inf>req</inf> of water in equilibrium with its vapour is measured from room temperature to 280°C at a frequency of 2.426 GHz. The water sample, sealed in a thick-walled borosilicate capillary tube, is heated to a preset temperature and is rapidly introduced in a rectangular TE103 resonant cavity. The change in resonant frequency and Q-factor are measured and are used to compute the real and imaginary parts of the complex permittivity of water. Results show a monotonic decrease of ε'<inf>r</inf> with temperature. More interestingly, ε"<inf>req</inf> initially decreases with rising temperature, reaching a minimum at 220 °C before increasing gradually with temperature. We attribute these effects to a combination of a weakening of the hydrogen bonding network and to enhanced ionic dissociation of water molecules at high temperatures.
Les appareillages de synthese chimique chauffes par micro-ondes sont actuellement limites a 25 mp... more Les appareillages de synthese chimique chauffes par micro-ondes sont actuellement limites a 25 mpa et 270 degres celsius du fait de l'utilisation d'elements en polymere. L'objectif de ce travail est de coupler une source micro-onde a un autoclave de facon a pouvoir l'utiliser pour des reactions en milieu aqueux a des pressions superieures a 100 mpa et des temperatures comparables au point critique de l'eau (374 degres celsius). Cela a aussi necessite la mesure de l'absorption micro-onde de l'eau a temperature et pression elevees. Comme illustration, l'appareillage developpe a ete applique a la synthese du dioxyde de molybdene finement divise par la technique solvothermale et a l'inactivation de bacteries par l'effet de la pression et de la temperature.
Progress In Electromagnetics Research C
This paper presents the design and fabrication of a coplanar waveguide (CPW) rectenna using a seq... more This paper presents the design and fabrication of a coplanar waveguide (CPW) rectenna using a sequential modular approach. The rectenna is printed on high permittivity, low-loss board ARLON AD1000 (r = 10.35 and tan δ = 0.0023 @ 10 GHz). The rectifier section is realized with a single reverse-biased schottky diode SMS-7630 in reverse topology for which a diode model is obtained at −20 dBm for frequencies F 0 = 2.45 GHz and 2F 0 = 4.9 GHz. The low-pass filter and the impedance matching are synthesized from passive CPW structures. Co-simulation technique is used to overcome CPW simulation limitations and to integrate the diode characteristics. The antenna consists of a circular slot loop antenna with stub matching such that its input impedance is close to 50 Ω. The goal of this work is to design a rectifier to simplify and speed up the fabrication process of a rectenna array. We reduced the number of processes to etch the rectifier on the board and minimized the number of lumped elements. At −20 dBm, simulation of the rectifier with an ideal impedance matching network shows rectification at 2.45 GHz with efficiency of 12.8%. The rectifier and rectenna show efficiency of approximately 10% at an operating frequency of 2.48 GHz.
2016 IEEE Radio and Antenna Days of the Indian Ocean (RADIO), 2016
2016 IEEE Radio and Antenna Days of the Indian Ocean (RADIO), 2016
2015 Radio and Antenna Days of the Indian Ocean (RADIO), 2015
2015 Radio and Antenna Days of the Indian Ocean (RADIO), 2015
Journal of Electrostatics, 2013
Models relating the coupling coefficient of coupled circuits to their physical layout and separat... more Models relating the coupling coefficient of coupled circuits to their physical layout and separation are essentially empirical in nature and have, until very recently, been available exclusively for inductive systems. In this work, we propose elementary models for representing the evolution, with distance, of the coupling coefficient between two dipoles arranged in different configurations. Both the electric and magnetic coupling cases are examined. We demonstrate that in the case of electrically coupled dipoles, with due consideration for specific practical constraints, the coupling coefficient is optimal when the dipoles are asymmetrical and arranged in an axial configuration. We show that the rate of fall of coupling coefficient increases with the relative separation between the dipoles. Finally, a simple formula for estimating the range of all non-radiating resonant power transport devices is proposed.
IOP Conference Series: Materials Science and Engineering, 2013
ABSTRACT
IOP Conference Series Materials Science and Engineering
ABSTRACT
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Papers by Shailendra oree