Photo-electrocatalytic methanol oxidation on Pd decorated BiOI nanoparticles in alkali

Journal of Materials Science - Palladium–bismuth oxoiodide nanocomposites of various molar ratios of Pd and BiOI have been synthesized by the facile solvothermal method following the chemical...     

Weighted Ternary Tree Approach for Secure Group Communication Among Mobile Applications

Wireless Personal Communications - Recent trends and clustered technology in the IT industries create usage of various hand-held computing devices like mobile phones, digitizer, modem, tablets etc....     

A survey of imperatives and action representation formalisms

Representation and reasoning of actions is a wide spread area in the domain of Artificial Intelligence. The representation involves natural language instructions, which are based on the linguistic concepts and the reasoning methodology deals with the logical structures. In the computational domain, several theories pertaining to the state-space approach have been proposed to represent and reason out actions. Considering these aspects, this paper provides an account of work from the viewpoint of linguistics, logic and action representation formalisms. Based on this study, this paper then proposes a seven axes categorization scheme, that can be used to compare and analyze different theories.     

Formulae for determining heterodyne system spurious frequencies that coincide with desired output frequency

In this paper, formulae to determine the lowest order and other higher order spurious frequencies that coincide with desired output signal frequencies of mixers have been derived. The proposed formulae give general expressions that are suitable for any order of heterodyne mixing. The formulae have been verified using a suitable example and compared with the simulation results obtained through the radio frequency simulation software of Advanced Design System. The formulae directly reveal the order of the troublesome spurious frequencies that the designers would encounter in heterodyne systems. In comparison with these direct formulae, the results of existing spurious analysis software are based on the maximum order of simulation carried out. Based on these simulations, the coinciding spurious components have to be manually sorted out. Proposed formulae are quick tools used by the microwave system and circuit designers for choosing and finalizing heterodyne frequencies in their designs without the need for any simulations.     

Optimization study of the femtosecond laser-induced forward-transfer process with thin aluminum films

The parameters for an effective laser-induced forward-transfer (LIFT) process of aluminum thin films using a femtosecond laser are studied. Deposited feature size as a function of laser fluence, donor film thickness, quality of focus, and the pulse duration are varied, providing a metric of the most desirable conditions for femtosecond LIFT with thin aluminum films.     

Electrical properties of SiO2/TiO2 high-k gate dielectric stack

The trapping/detrapping behavior of charge carriers in ultrathin SiO₂/TiO₂ stacked gate dielectric during constant current (CCS) and voltage stressing (CVS) has been investigated. Titanium tetrakis iso-propoxides (TTIP) was used as the organometallic source for the deposition of ultra-thin TiO₂ films at low temperature (<200 °C) on strained-Si/relaxed-Si_0.8Ge_0.2 heterolayers by plasma-enhanced chemical vapor deposition (PECVD) in a microwave (700 W, 2.45 GHz) plasma cavity discharge system at a pressure of 66.67 Pa. Stress-induced leakage current (SILC) through SiO₂/TiO₂ stacked gate dielectric is modeled by taking into account the inelastic trap-assisted tunneling (ITAT) mechanism via traps located below the conduction band of TiO₂ layer. The increase in the gate current density observed during CVS from room temperature up to 125 ^oC has been analyzed and modeled considering both the buildup of charges in the layer as well as the SILC contribution. Trap generation rate and trap cross-section are extracted. A capture cross-section in the range of 10⁻¹⁹ cm² as compared to 10⁻¹⁶ cm² in SiO₂ has been observed. A temperature-dependent trap generation rate and defects have also been investigated using time-dependent current density variation during CVS. The time dependence of defect density variation is calculated within the dispersive transport model, assuming that these defects are produced during random hopping transport of positively charge species in the insulating high-k stacked layers. SILC generation kinetics, i.e. defect generation probability under different injected fluences for various high-constant stress voltages in both polarities have been studied. An empirical relation between trap generation probability and applied stress voltage for various injected fluences has been developed.     

Defect studies on as-synthesized and purified carbon nanostructures produced by arc-discharge in solution process

Carbon nanostructures are synthesized using a novel arc-discharge in solution process. A multitude of defects on nanotubes and nanostructures is found. Evidence of these defects in as-synthesized carbon nanostructures is explored using high-resolution transmission electron microscopy (HRTEM). Tri-, tetra-, penta-, hexa-, heptagonal, toroidal, oval, and spherical nanoshells are found in HRTEM investigation along with carbon nanotubes, carbon nanohorns, carbon rods, nanoporous carbon, dislodged graphene sheets, and amorphous carbon. Purifications are carried out through two oxidation methods to eliminate the amorphous carbon. Several different defects caused by oxidations are also found in purified samples.     

Spiral growth of one dimensional titania nanostructures using anodic oxidation

One dimensional spiral titania nanostructures were obtained by anodization of pure titanium from fluoride containing solutions of phosphoric acid. The formation of nanotubes was found to be dependant on current density. Field Emission Scanning Electron Microscopy (FESEM) shows the diameter of tubes around 70-100 nm which is consistent with the High Resolution Transmission Electron Micrographs (HRTEM) and Atomic Force Microscopy (AFM) images. HRTEM showed the one dimensional growth as spiral in nature which was also supported by AFM images. This anisotropic growth is compared with the possible growth mechanisms.     

Applicability of equations of state for modeling helium systems

Proper design of helium systems with large number of components and involved configurations such as helium liquefiers/refrigerators requires the use of tools like process simulators. The accuracy of the simulation results, to a great extent, depends on the accuracy of property data. For computation of thermodynamic properties of helium, the 32-parameter MBWR equation of state proposed by McCarty and Arp [1] is widely used. However, it is computationally involved, makes the simulation process more time-consuming and sometimes leads to computational difficulties such as numerical oscillations, divergence in solution especially, when the process operates over a wide thermodynamic region and is constituted of many components. Substituting MBWR EOS by simpler equations of state (EOS(s)) at selected thermodynamic planes, where the simpler EOS(s) have the similar accuracy as that of MBWR EOS may enhance ease of computation. In the present paper, the methodology to implement this concept has been elucidated with examples of steady state and dynamic simulation of helium liquefier/refrigerator based on Collins cycle. The above concept can be applied to thermodynamic analysis of other process cycles where computation of fluid property is involved.