Numerical Analysis of Interaction Cavity for 1.5 MW/127.5 GHz Gyrotron

This paper presents the design of 127.5 GHz ITER start-up gyrotron interaction cavity. Particle-in-Cell electromagnetic simulation approach has been used for the cold cavity and beam-wave interaction analysis. In-house developed code GCOMS has been used for the mode selection. TE_24,8 mode has been chosen as the operating mode. The simulation results show the output power more than 1.5 MW at the operating frequency of 127.8 GHz and the cavity centre magnetic field of 5.1 T. The study of the parametric dependency of the output power and the efficiency on the electron beam and the cavity geometry parameters has also been carried out.     

Design and Misalignment Analysis of 140 GHz, 1.5 MW Gyrotron Interaction Cavity for Plasma Heating Applications

In this paper the design of 140 GHz, 1.5 MW gyrotron interaction cavity is described in detail. The interaction cavity is designed and simulated by using Particle-in-Cell code for TE_24,8 operating mode. The obtained simulation results show more than 1.5 MW of output power at 139.83 GHz of frequency. A thorough parametric and misalignment study is also presented to support the actual fabrication and assembling of the device.     

Synthesis and properties of poly(arylene ether)s based on 3‐pentadecyl 4,4'‐biphenol

A new biphenol, 3‐pentadecyl 4,4′‐biphenol, was synthesized starting from 3‐pentadecylphenol and was polycondensed with 4,4′‐difluorobenzophenone, 1,3‐bis(4‐fluorobenzoyl)benzene and bis(4‐fluorophenyl)sulfone to obtain poly(arylene ether)s with biphenylene linkages in the backbone and pendent pentadecyl chains. Inherent viscosities and number‐average molecular weights (M_n) of the poly(arylene ether)s were in the range 0.50 ? 0.81 dL g^?1 and 2.2 × 10⁴ ? 8.3 × 10⁴, respectively. Detailed NMR spectroscopic studies of the poly(arylene ether)s indicated the presence of constitutional isomerism which existed because of the non‐symmetrical structure of 3‐pentadecyl 4,4′‐biphenol. The poly(arylene ether)s readily dissolved in common organic solvents such as dichloromethane, chloroform and tetrahydrofuran and could be cast into tough, transparent and flexible films from their chloroform solutions. The poly(arylene ether)s exhibited T_g values in the range 35–60 °C which are lower than that of reference poly(arylene ether)s without pentadecyl chains. The 10% decomposition temperatures (T₁₀) of the poly(arylene ether)s were in the range 410–455 °C indicating their good thermal stability. A gas permeation study of poly(ether sulfone) containing pendent pentadecyl chains revealed a moderate increase in permeability for helium, hydrogen and oxygen. However, there was a large increase in permeability for carbon dioxide which could be attributed to the internal plasticization effect of pendent pentadecyl chains. © 2016 Society of Chemical Industry     

VC3H3 organometallic compound: A possible hydrogen storage material

This work reports the hydrogen uptake capacity of V-capped and V-inserted VC₃H₃ organometallic complexes using density functional theory (DFT) with different exchange and correlation functionals. Maximum of five and three H₂ molecules are adsorbed on V-capped and V-inserted VC₃H₃ structures, respectively. This corresponds to the hydrogen uptake capacity of 10.07 and 6.66 wt% for the former and the latter, respectively. The first added hydrogen molecule is adsorbed in dihydride form on V-capped as well as V-inserted VC₃H₃ complex. A complex with a dissociated hydrogen molecule adsorbed has higher binding energy than that of molecular hydrogen adsorbed. The nature of interactions between H₂ molecules and organometallic complex is studied using many-body analysis approach. Thermo-chemistry calculations are performed to see whether H₂ adsorption on V-capped complex is energetically favorable or not for room temperature hydrogen storage.     

Environmental-barrier coating ceramics for resistance against attack by molten calcia-magnesia-aluminosilicate (CMAS) glass: Part II, β-Yb2Si2O7 and β-Sc2Si2O7

The high-temperature (1500?°C) interactions of two promising dense, polycrystalline EBC ceramics, β-Yb₂Si₂O₇ and β-Sc₂Si₂O₇, with a calcia-magnesia-aluminosilicate (CMAS) glass have been explored as part of a model study. Unlike YAlO₃ and γ-Y₂Si₂O₇ in the accompanying Part I paper, little or no reaction is found between the Y-free EBC ceramics and the CMAS. In the case of β-Yb₂Si₂O₇, a small amount of reaction-crystallization product Yb-Ca-Si apatite solid solution (ss) forms, whereas none is detected in the case of β-Sc₂Si₂O₇. The CMAS glass penetrates into the grain boundaries of both EBC ceramics, and they both suffer from a new type of ‘blister’ cracking damage. This is attributed to the through-thickness dilatation-gradient caused by the slow grain-boundary-penetration of the CMAS glass. The success of a ‘blister’-damage-mitigation approach is demonstrated, where 1?vol% CMAS glass is mixed into the β-Yb₂Si₂O₇ powder prior to sintering. The CMAS-glass phase at the grain boundaries promotes rapid CMAS-glass penetration, thereby avoiding the dilatation-gradient.     

On Exploiting Dynamic Trusted Routing Scheme in Delay Tolerant Networks

Wireless Personal Communications - Delay tolerant network routing is characterized by sparsely or densely populated nodes. In such network routing with limited resource like buffer space is a...     

Thermal and Structural Analysis of MIG for Gyrotron

The paper presents the thermal analysis of the Magnetron Injection Gun for 42 GHz, 200 kW gyrotron, which is used to provide a high quality hollow electron beam. The Finite Element Analysis code ANSYS has been used for the thermal and the structural simulation. The thermal analysis of the structure of Magnetron Injection Gun has been carried out to find out the effect of heater temperature required for maintaining more than 1,000°C at cathode emitter surface to get 10 A of beam current. These results have been experimentally verified. The experimental results closely match the ANSYS results. The effect of the radial expansion of the emitter radius on beam quality has also been analyzed.     

Design,optimization and evaluation of poly-ɛ-caprolactone (PCL) based polymeric nanoparticles for oral delivery of lopinavir

Lopinavir (LPV)-loaded poly-ε-caprolactone (PCL) nanoparticles (NPs) were prepared by emulsion solvent evaporation technique. Effects of various critical factors in preparation of loaded NPs were investigated. Box–Behnken design (BBD) was employed to optimize particle size and entrapment efficiency (EE) of loaded NPs. Optimized LPV NPs exhibited nanometeric size (195.3?nm) with high EE (93.9%). In vitro drug release study showed bi-phasic sustained release behavior of LPV from NPs. Pharmacokinetic study results in male Wistar rats indicated an increase in oral bioavailability of LPV by 4-folds after incorporation into PCL NPs. From tissue distribution studies, significant accumulation of loaded NPs in tissues like liver and spleen indicated possible involvement of lymphatic route in absorption of NPs. Mechanistic studies using rat everted gut sac model revealed endocytosis as a principal mechanism of NPs uptake. In vitro rat microsomal metabolism studies demonstrated noticeable advantage of LPV NPs by affording metabolic protection to LPV. These studies indicate usefulness of PCL NPs in enhancing oral bioavailability and improving pharmacokinetic profile of LPV.     

Perovskite-type catalytic materials for environmental applications

Perovskites are mixed-metal oxides that are attracting much scientific and application interest owing to their low price, adaptability, and thermal stability, which often depend on bulk and surface characteristics. These materials have been extensively explored for their catalytic, electrical, magnetic, and optical properties. They are promising candidates for the photocatalytic splitting of water and have also been extensively studied for environmental catalysis applications. Oxygen and cation non-stoichiometry can be tailored in a large number of perovskite compositions to achieve the desired catalytic activity, including multifunctional catalytic properties. Despite the extensive uses, the commercial success for this class of perovskite-based catalytic materials has not been achieved for vehicle exhaust emission control or for many other environmental applications. With recent advances in synthesis techniques, including the preparation of supported perovskites, and increasing understanding of promoted substitute perovskite-type materials, there is a growing interest in applied studies of perovskite-type catalytic materials. We have studied a number of perovskites based on Co, Mn, Ru, and Fe and their substituted compositions for their catalytic activity in terms of diesel soot oxidation, three-way catalysis, N₂O decomposition, low-temperature CO oxidation, oxidation of volatile organic compounds, etc. The enhanced catalytic activity of these materials is attributed mainly to their altered redox properties, the promotional effect of co-ions, and the increased exposure of catalytically active transition metals in certain preparations. The recent lowering of sulfur content in fuel and concerns over the cost and availability of precious metals are responsible for renewed interest in perovskite-type catalysts for environmental applications.