Ultrasonic assisted synthesis of activated carbon for electromagnetic shielding material from rice husk fibre

911-917Synthesis of any biomaterials/biocomposites for different applications like in electromagnetic wave communication, radar, satellite system needs the processing of its raw material. The suitability of raw material is a challenging task for fabrication technology depending on its type of work performed and efficiency. The surface modification/surface bleaching is performed to facilitate the fillers and matrix for good interlocking between them for improvement in mechanical strength. The material used for microwave absorption or energy storage device in low observable technology (LOT) needs good mechanical strength. The present paper encloses the treatment of raw materials like rice husk with suitable blended chemicals maleic acid with different alcohols. The optimized blended chemicals are determined by computation of different acoustic parameters with the propagation of ultrasonic wave in low frequency range. The rice husk are treated with the optimized blended solution which results in increase of porosity of the material and hence for the fabrication of composites. The element dispersion study images of untreated and treated rice husk signify the suitability of the material for synthesis of microwave absorbing materials

Local magnetism of isolated Mo atoms at substitutional and interstitial sites in Yb metal : Experiment and Theory

Using TDPAD experiment and local spin density calculations, we have observed large 4d moments on isolated Mo atoms at substitutional and octahedral interstitial lattice sites in Yb metal, showing Curie-Weiss local susceptibility and Korringa like spin relaxation rate. As a surprising feature, despite strong hybridization with the Yb neighbours, interstitial Mo atoms show high moment stability with small Kondo temperature. While, magnetism of Mo, at substitutional site is consistent with Kondo type antiferromagnetic d-sp exchange interaction, we suggest that moment stability at the interstitial site is strongly influenced by ferromagnetic polarization of Yb-4f5d band electrons.Comment: 4 pages, 4 figure

A Novice Approach of Designing CMOS Based Switchable Filters for ASP Applications

A switchable filter can be designed and fabricated with the desired range and parameters, materials say quartz substrate for RF MEMS based applications. The mathematical modeling of the resonators using the desired characteristics of the capacitive coupled filters can be implemented with low insertion loss. In order to design this filter, one can employ a PIN diode along with a semi-lumped resonator. This PIN diode has been used so as it performs the function of electronic switching i.e. the activating and deactivating the filter circuit action without any compromise in the overall performance of the circuit. These filters circuit are designed and implemented in a way so that it can accommodate the external quality factor in order to ensure a good impedance match at each band of operation. The most dominant parameters and characteristics of the second order switchable filter realization. In this work, the author has put an effort to discuss the most desired parameters of the various switchable filters. In these filter circuits, CMOS devices has been used to design because of their well accepted features i.e. low power loss and requirement of low input signal for operation in addition to other ones. The performance of the proposed CMOS based switchable filters has been discussed with its simulated results that have been carried out by using pSpice software with 0.18 micron technology. The insertion loss of this circuit is with the acceptable limits i.e. 2.9 dB and a tenability within two desired frequencies

Ultrasonic assisted synthesis of activated carbon for electromagnetic shielding material from rice husk fibre

Synthesis of any biomaterials/biocomposites for different applications like in electromagnetic wave communication, radar, satellite system needs the processing of its raw material. The suitability of raw material is a challenging task for fabrication technology depending on its type of work performed and efficiency. The surface modification/surface bleaching is performed to facilitate the fillers and matrix for good interlocking between them for improvement in mechanical strength. The material used for microwave absorption or energy storage device in low observable technology (LOT) needs good mechanical strength. The present paper encloses the treatment of raw materials like rice husk with suitable blended chemicals maleic acid with different alcohols. The optimized blended chemicals are determined by computation of different acoustic parameters with the propagation of ultrasonic wave in low frequency range. The rice husk are treated with the optimized blended solution which results in increase of porosity of the material and hence for the fabrication of composites. The element dispersion study images of untreated and treated rice husk signify the suitability of the material for synthesis of microwave absorbing materials

Fluctuation Induced Non-Fermi Liquid Behavior near a Quantum Phase Transition in Itinerant Electron Systems

The signature for a non-Fermi liquid behavior near a quantum phase transition has been observed in thermal and transport properties of many metallic systems at low temperatures. In the present work we consider specific examples of itinerant ferromagnet as well as antiferromagnet in the limit of vanishing transition temperature. The temperature variation of spin susceptibility, electrical resistivity, specific heat, and NMR relaxation rates at low temperatures is calculated in the limit of infinite exchange enhancement within the frame work of a self consistent spin fluctuation theory. The resulting non-Fermi liquid behavior is due to the presence of the low lying critically damped spin fluctuations in these systems. The theory presented here gives the leading low temperature behavior, as it turns out that the fluctuation correlation term is always smaller than the mean fluctuation field term in three as well as in two space dimensions. A comparison with illustrative experimental results of these properties in some typical systems has been done. Finally we make some remarks on the effect of disorder in these systems.Comment: File RevTex, 7 Figures available on request, Abstract and text modified, To appear in Phys. Rev.