A Study on Potentiality of Silver as an Investment Asset

In the last few years the countries around the world are facing burden of global economic slowdown and the same is indicated in their slower GDP growth and falling stock market prices. Even under these precarious conditions the commodity markets are experiencing considerable growth and are offering good returns to the investors. Among all commodities, though considered as highly volatile, silver is a very attractive commodity to invest. In contrast to the common belief, silver is relatively a safe investment in the long run and assures significantly high returns to the investors. The present study aims to prove potentiality of silver as an investment asset using simple risk, return analysis and other basic fundamentals. The results of the analysis prove that silver is a good asset for investment vis-à-vis gold and stock markets and is a consistent performer under different economic conditions

Exploiting Aging Benefits for the Design of Reliable Drowsy Cache Memories

In this paper, we show how beneficial effects of aging on static power consumption can be exploited to design reliable drowsy cache memories adopting dynamic voltage scaling(DVS) to reduce static power. First, we develop an analytical model allowing designers to evaluate the long-term threshold voltage degradation induced by bias temperature instability (BTI)in a drowsy cache memory. Through HSPICE simulations, we demonstrate that, as drowsy memories age, static power reduction techniques based on DVS become more effective because of reduction in sub-threshold current due to BTI aging. We develop a simulation framework to evaluate trade-offs between static power and reliability, and a methodology to properly select the “drowsy” data retention voltage. We then propose different architectures of a drowsy cache memory allowing designers to meet different power and reliability constraints. The performed HSPICE simulations show a soft error rate and static noise margin improvement up to 20.8% and 22.7%, respectively, compared to standard aging unaware drowsy technique. This is achieved with a limited static power increase during the very early lifetime, and with static energy saving of up to 37% in 10 years of operation, at no or very limited hardware overhead

Periodontal Probes - A Review

A periodontal probe till today remains the most important diagnostic tool in periodontal diseases. A probe is used to make initial assessment, followed by detailed evaluation to determine the extent and degree of severity of disease and tissue destruction for specific treatment planning. During treatment the probe is applied to assess the progress. After treatment, use of the probe helps to determine the completion of professional services as recognized by the health status of the tissue. This article provides the reader with the review of periodontal probes which throws light on clinical presentation, diagnosis, prevention and management

Combustion synthesis, characterization and Raman studies of ZnO nanopowders

Spherical shaped ZnO nanopowders (14-50 nm) were synthesized by a low temperature solution combustion method in a short time <5 min. Rietveld analysis show that ZnO has hexagonal wurtzite structure with lattice constants a = 3.2511(1) , c = 5.2076(2) , unit cell volume (V) = 47.66(5) () 3 and belongs to space group P63mc. SEM micrographs reveal that the particles are spherical in shape and the powders contained several voids and pores. TEM results also confirm spherical shape, with average particle size of 14-50 nm. The values are consistent with the grain sizes measured from Scherrer's method and Williamson-Hall (W-H) plots. A broad UV-vis absorption spectrum was observed at �375 nm which is a characteristic band for the wurtzite hexagonal pure ZnO. The optical energy band gap of 3.24 eV was observed for nanopowder which is slightly lower than that of the bulk ZnO (3.37 eV). The observed Raman peaks at 438 and 588 cm -1 were attributed to the E 2 (high) and E 1 (LO) modes respectively. The broad band at 564 cm -1 is due to disorder-activated Raman scattering for the A 1 mode. These bands are associated with the first-order Raman active modes of the ZnO phase. The weak bands observed in the range 750-1000 cm -1 are due to small defects. © 2011 Elsevier B.V. All Rights Reserved

Synthesis, luminescence properties and EPR investigation of hydrothermally derived uniform ZnO hexagonal rods

One-dimensional (1D) zinc oxide (ZnO) hexagonal rods have been successfully synthesized by surfactant free hydrothermal process at different temperatures. It can be found that the reaction temperature play a crucial role in the formation of ZnO uniform hexagonal rods. The possible formation processes of 1-D ZnO hexagonal rods were investigated. The zinc hydroxide acts as the morphology-formative intermediate for the formation of ZnO nanorods. Upon excitation at 325 nm, the sample prepared at 180 °C show several emission bands at 400 nm (∼3.10 eV), 420 nm (∼2.95 eV), 482 nm (∼2.57 eV) and 524 nm (∼2.36 eV) corresponding to different kind of defects. TL studies were carried out by pre-irradiating samples with γ-rays ranging from 1 to 7 kGy at room temperature. A well resolved glow peak at ∼354 °C was recorded which can be ascribed to deep traps. Furthermore, the defects associated with surface states in ZnO nano-structures are characterized by electron paramagnetic resonance

EPR and photoluminescence studies of ZnO:Mn nanophosphors prepared by solution combustion route

Nanocrystalline ZnO:Mn (0.1 mol%) phosphors have been successfully prepared by self propagating, gas producing solution combustion method. The powder X-ray diffraction of as-formed ZnO:Mn sample shows, hexagonal wurtzite phase with particle size of ∼40 nm. For Mn doped ZnO, the lattice parameters and volume of unit cell (a = 3.23065 Å, c = 5.27563 Å and V = 47.684 (Å)3) are found to be greater than that of undoped ZnO (a = 3.19993 Å, c = 5.22546 Å and V = 46.336 (Å)3). The SEM micrographs reveal that besides the spherical crystals, the powders also contained several voids and pores. The TEM photograph also shows the particles are approximately spherical in nature. The FTIR spectrum shows two peaks at ∼3428 and 1598 cm−1 which are attributed to O–H stretching and H–O–H bending vibration. The PL spectra of ZnO:Mn indicate a strong green emission peak at 526 nm and a weak red emission at 636 nm corresponding to 4T1 → 6A1 transition of Mn2+ ions. The EPR spectrum exhibits fine structure transition which will be split into six hyperfine components due to 55Mn hyperfine coupling giving rise to all 30 allowed transitions. From EPR spectra the spin-Hamiltonian parameters have been evaluated and discussed. The magnitude of the hyperfine splitting (A) constant indicates that there exists a moderately covalent bonding between the Mn2+ ions and the surrounding ligands. The number of spins participating in resonance (N), its paramagnetic susceptibility (χ) have been evaluated

EPR, thermo and photoluminescence properties of ZnO nanopowders

Nanocrystalline ZnO powders have been synthesized by a low temperature solution combustion method. The photoluminescence (PL) spectrum of as-formed and heat treated ZnO shows strong violet (402, 421, 437, 485 nm) and weak green (520 nm) emission peaks respectively. The PL intensities of defect related emission bands decrease with calcinations temperature indicating the decrease of Zn i and V o + caused by the chemisorptions of oxygen. The results are correlated with the electron paramagnetic resonance (EPR) studies. Thermoluminescence (TL) glow curves of gamma irradiated ZnO nanoparticles exhibit a single broad glow peak at �343 °C. This can be attributed to the recombination of charge carriers released from the surface states associated with oxygen defects, mainly interstitial oxygen ion centers. The trapping parameters of ZnO irradiated with various γ-doses are calculated using peak shape method. It is observed that the glow peak intensity increases with increase of gamma dose without changing glow curve shape. These two characteristic properties such as TL intensity increases with gamma dose and simple glow curve structure is an indication that the synthesized ZnO nanoparticles might be used as good TL dosimeter for high temperature application. © 2011 Elsevier B.V. All Rights Reserved

A Regression Strategy for Analyzing Environmental Data Generated by Spatio- Temporal Processes

Abstract Highly complex spatio-temporal environmental data sets are becoming common in ecology because of the increasing use of large-scale simulation models and automated data collection devices. The spatial and temporal dimensions present real and difficult challenges for the interpretation of these data. A particularly difficult problem is that the relationship among variables can vary in dramatically in response to environmental variation; consequently, a single model may not provide adequate fit. The temporal dimension presents both opportunities for improved prediction because explanatory variables sometimes exert delayed effects on response variables, and problems because variables are often serially correlated. This article presents a regression strategy for accommodating these problems. The strategy is illustrated by a case study of simulated net primary production (SNPP) that compares ocean-atmosphere indices to terrestrial climate variables as predictors of SNPP across the conterminousUnited States, and describes spatial variation in the relative importance of terrestrial climate variables towards predicting SNPP. We found that the relationship between ocean-atmosphere indices and SNPP varies substantially over the United States, and that there is evidence of a substantive link States . E only in the western portions of the United vidence of multi-year delays in the effect of terrestrial climate effects on SNPP were also found

Structural, EPR, photo and thermoluminescence properties of ZnO:Fe nanoparticles

Zn (1-x)Fe (x)O (1+0.5x) (x = 0.5-5 mol) nanoparticles were synthesized by a low temperature solution combustion route. The structural characterization of these nanoparticles by PXRD, SEM and TEM confirmed the phase purity of the samples and indicated a reduction in the particle size with increase in Fe content. A small increase in micro strain in the Fe doped nanocrystals is observed from W-H plots. EPR spectrum exhibits an intense resonance signal with effective g values at g â 2.0 with a sextet hyperfine structure (hfs) besides a weak signal at g â 4.13. The signal at g â 2.0 with a sextet hyperfine structure might be due to manganese impurity where as the resonance signal at g â 4.13 is due to iron. The optical band gap E g was found to decrease with increase of Fe content. Raman spectra exhibit two non-polar optical phonon (E 2) modes at low and high frequencies at 100 and 435 cm -1 in Fe doped samples. These modes broaden and disappear with increase of Fe dopant concentration. TL measurements of γ-irradiated (1-5 kGy) samples show a main glow peak at 368°C at a warming rate of 6.7°Cs -1. The thermal activation parameters were estimated from Glow peak shape method. The average activation energy was found to be in the range 0.34-2.81 eV. © 2012 Elsevier B.V. All rights reserved

Comparison of immune responses in parenteral FaeG DNA primed pigs boosted orally with F4 protein or reimmunized with the DNA vaccine

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