Physical implementation of an antimask in URA based coded mask systems

X- and gamma-ray astronomy experiments which employ rectangular URA coded masks alone show artifacts in the images reconstructed due to nonuniform background levels in the detector plane. The employment of a separate antimask in addition to the mask in observations is useful to eliminate this problem. We propose here a method to implement the antimask with the same mask, utilizing the antisymmetric properties in the mask pattern, thereby avoiding the need for a separate antimask in an experiment. Simulations performed with this mask-antimask system are presented to show its advantages.     

Act locally and think globally

Summary A combined approach of molecular dynamics (MD) simulations and the method of real-space Green's function to study properties of complex systems with reduced symmetry is presented. MD simulations provide the equilibrium configuration of the complex system under consideration. The efficiency and flexibility of the method of real-space Green's function allow a detailed examination of any locality of interest. The local analysis based on the combined approach is thus a powerful and convenient tool to study how the interplay between the nature of the local environment and the remaining system affects the properties of the system.     

The effects of kinetic variables on the structure of copper deposits cemented on pure aluminum discs: A scanning electron microscopic study

The structural characteristics of copper deposits resulting from copper cementation on pure aluminum are presented. The effect of chloride ion concentration, rotational speed of the aluminum disc, hydrogen ion concentration, copper ion concentration, and temperature on the nature and morphology of the deposits was investigated. Different copper deposit structures, viz. bulbous, massive crystalline, thick dendrites with leaf-like secondary arms, and dendrites of different degrees of fineness and texture were observed in the present study utilizing the scanning electron microscope. Deposit morphology was greatly modified for variations of chloride ion up to 25 mg l^?1 and for increases in temperature up to 40° C. The maximum rate of copper cementation on pure aluminum was usually associated with a fine, dendritic structure.     

Microstructure and mechanical properties of spark plasma-sintered La2O3 dispersion-strengthened W-Ni-Fe alloy

An investigation of lanthanum oxide (La2O3)addition to tungsten heavy alloy (WHA) with a ternary composition of W-7Ni-3Fe was reported in this study.The mixed p...     

Proximal spatial vector and affinity coefficient for multimodal biometric secured social network communication

World Wide Web - Using multimodalities, the field of biometric is receiving widespread acceptance for efficient communication between users in social network. Hence, suitable designing of...     

Advanced Satellite Image Classification of Various Resolution Image Using a Novel Approach of Deep Neural Network Classifier

Wireless Personal Communications - Image registration is computationally intensive and applied in a variety of applications, for example, multispectral classification, change recognition, climate...     

Investigation of polymer dynamics in chitosan-maghemite nanocomposites: a potential green superparamagnetic material

Magnetic composites with superparamagnetic properties have attracted great scientific interest recently. In this article we have investigated chitosan-maghemite (γ-Fe₂O₃) nanocomposite. We have analyzed the effect of temperature and the concentration of maghemite nanoparticles upon the relaxation behaviour of the nanocomposite using Broad band dielectric spectroscopy (BDS). Additionally, various characterization techniques such as X-ray diffraction (XRD), Fourier transform infra red spectra (FTIR), Scanning electron microscopy (SEM), Transmission electron spectroscopy (TEM), Thermo gravimetric Analysis (TGA), Vibrating Sample Magnetometer (VSM), Atomic Force Microscopy (AFM) and Raman spectroscopy have been used for our investigation. Our investigation shows that maghemite nanoparticles interact with chitosan leading to morphological changes in the films and results in modifications in the dielectric and electrical characteristics of the nanocomposite. New relaxations have been identified and their modifications due to maghemite nanoparticles have been investigated. The nanocomposites exhibit superparamagnetic behaviour. This research will benefit research in battery technology and super capacitors.     

Relation between group combustion and drop array studies

Spray combustion modeling requires a knowledge of the strength of the mass and heat sources for each drop in the spray. Since sprays involve a large number of drops, interactive transport processes must be accounted for in estimating the source strengths of the drops. Earlier approaches (called array studies) considered a finite number of drops (2 to 9), and accounted for the three dimensional variation of temperature and species mass fraction profiles in order to determine an evaporation/combustion correction factor. This correction factor is defined as the ratio of the average strength of each drop in the array to the strength of the drop if it is kept in an isolated environment. The current approach utilizes group combustion theory which involves a large number of drops, assumes top hat profiles in the interstitial space between the drops, and accounts for their variation in the radial direction. The correction factor is again determined. This paper reports the results of the current group combustion approach and compares these results with those from array studies when the group combustion approach is extended to an array consisting of as few as 2 to 9 drops. The change in transport rate due to proximity of other drops is accounted for in the present group combustion approach. An unexpected result is the close agreement of the results obtained from group combustion approach with those results from array studies. A simple algebraic expression is given for the correction factor in terms of l/a ratio and total number of drops for a 2 to 9 drop array.     

Synthesis and characterization of MWCNT impregnated with different loadings of SnO2 nanoparticles for hydrogen storage applications

Multi-walled carbon nanotubes (MWCNTs) loaded with different wt % of tin oxide (MWCNT: SnO₂) nanocomposites have been synthesized by impregnation method and their hydrogen uptake capacity is investigated. The hydrogen storage capacity of MWCNT: SnO₂ (3 wt %), MWCNT: SnO₂ (5 wt %), MWCNT: SnO₂ (7 wt %) and MWCNT: SnO₂ (9 wt %) composites is found to be 2.03, 1.95, 0.94 and 1.59 wt % respectively. The enhanced hydrogen storage capacity is due to SnOC bond formation and summative adsorption of hydrogen by MWCNT and SnO₂ nanoparticles. Moreover, physical/chemical properties of composites are examined by Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction, thermogravimetric and Raman analyses. Hydrogen adsorption and desorption behavior of the composites are analyzed using Raman and thermogravimetric analyses. The stored hydrogen is desorbed in the temperature range of 183 ?C-536 °C.