An integrated approach of designing functionality with security for distributed cyber-physical systems

The Journal of Supercomputing - In this work, we propose a multi-tier architectural model to separate functionality and security concerns for distributed cyber-physical systems. On the line of...     

Image Alignment in Pose Variations of Human Faces by Using Corner Detection Method and Its Application for PIFR System

Wireless Personal Communications - Major challenge faced by the recent face recognition techniques treat with pose variation during matching. When comparing different person images, the change in...     

Synthesis of single phase bismuth ferrite compound by reliable one-step method

We report the synthesis of polycrystalline BiFeO₃ compound by solid state route and its structural and magnetic properties were investigated. The structure confirmation and phase purity of the samples were investigated by X-ray diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) techniques. No signature of thermodynamically probable impurity phases was observed in these samples. The Rietveld refined structural parameters of the XRD pattern revealed rhombohedral (R3c) structure. Scanning Electron Microscopy images show samples with larger grain size. The Raman active modes predicted by the group theory confirmed the rhombohedral symmetry. The study of the oxidation states of Bi, Fe and O through XPS analysis indicated that the sample quality is not deteriorated by vacancies or other defects formation. The absence of iron based impurity phases is confirmed by the antiferromagnetic nature of the sample obtained by magnetization measurements.     

Studies on the use of N,N,N′,N′-Tetra(2-Ethylhexyl) Diglycolamide (TEHDGA) for Actinide Partitioning II: Investigation on Radiolytic Stability

Abstract

N,N,N′,N′-tetra(2-ethylhexyl)diglycolamide (TEHDGA) was found to be a promising extractant for actinide partitioning from high-level waste (HLW) (Part I). In order to evaluate the applicability of TEHDGA to the HLW partitioning process, investigations on its radiolytic stability were carried out. The present work deals with the studies on the uptake of americium by γ-irradiated 0.2 M TEHDGA/n-dodecane in the absence and presence of phase modifiers—di(n-hexyl)octanamide (DHOA), isodecanol and n-decanol—against the absorbed dose up to 1 × 10⁶ Gy in the presence of nitric acid at varying concentrations. The addition of phase modifiers suppressed the radiolysis of TEHDGA in n-dodecane and DHOA was found to be the most effective radiolysis suppressor. Investigations were also carried out on the degradation of neat TEHDGA by γ-irradiation, and it was attempted to isolate and identify its degradation products by instrumental analysis. The radiolysis study showed that the degradation products were formed by the cleavage of the –C-N bond, to eliminate an ethylhexyl group, and the bond adjacent to the ether bond. The results obtained for TEHDGA radiolysis were compared with that of its straight-chain isomer TODGA, and TEHDGA was observed to be more resistant to radiation than TODGA. The changes in the physico-chemical properties of γ-irradiated TEHDGA against the absorbed dose were also investigated.     

Further remarks on sequential point estimation of the mean of a multinormal population

Asymptotic behaviour of the regret is studied for the sequential procedure developed by Wang (1980) for the point estimation of the mean of a multinormal population. A condition on the initial sample size is also provided for which the regret is bounded.     

On the fundamentals of leakage aware real-time DVS scheduling for peak temperature minimization

As the consequence of the exponentially increased power density on integrated circuits, thermal issues are becoming critical in design of computing systems. Moreover, as both leakage and thermal issues have become more prominent in the deep sub-micron domain, a power and thermal aware design technique becomes less effective if the leakage/temperature dependency is not appropriately addressed. In this paper, we take into account the dependency among the leakage, the temperature, and the supply voltage in our theoretical analysis and explore the fundamental characteristics on how to employ dynamic voltage scaling (DVS) to reduce the peak operating temperature. We find that, for a specific interval, a real-time schedule using the lowest constant speed is not necessarily the optimal choice any more in minimizing the peak temperature. We identify the scenarios when a schedule using two different speeds can outperform the one using the lowest constant speed. In addition, we find that, when scheduling a periodic task set, the constant speed schedule is still the optimal solution for minimizing the peak temperature when the temperature is at its stable status. We formulate our conclusions into several theorems with formal proofs.     

An Eulerian MHD model for the analysis of magnetic flux compression by expanding diamagnetic fusion plasma sphere

The process of magnetic flux compression (MFC) inside a solenoid by expanding diamagnetic plasma sphere produced by an inertial fusion micro-explosions and its application as a direct energy conversion scheme to convert a part of plasma kinetic energy into pulsed electrical energy has been recently reported [1]. For a detailed analysis of this concept, an Eulerian multi-material MHD model is developed using magnetic vector potential formulation for electro-magnetic field calculations and classical volume-of-fluid method for material interface tracking. The diffusion term in the magnetic induction equation is solved implicitly while the advection terms are computed using a second-order MUSCL scheme. An iteration procedure using ADI scheme is used for the free space field calculation. In this paper, we describe the details of the new MHD model, its validation against the semi-analytical solutions (for magnetic Reynolds number ?1) of magnetic convective-diffusion equations and application to explore the concept of MFC by expanding plasma sphere. The simulation results show that the algorithm is capable of handling complex plasma dynamics inside the MFC system. Also, the results indicate the development and the evolution of MRT like instability near the stagnation point. The magnetic field diffusion into the plasma during the expansion phase is found to be negligible.     

Low‐Temperature Pretreatment of Lignocellulosic Biomass for Enhanced Biogas Production

Readily available lignocellulosic biomass as substrate for biogas plants is gaining popularity amongst biogas plant operators. Results of low‐temperature pretreatment (light cooking) of wheat straw to remove waxes and prepare the biomass for microbial action are described. Benefits of light cooking are low thermal energy demand and low investment cost compared to conventional techniques such as steam explosion. The novelty lies in utilizing the low temperature range 25–100 °C for pre‐soaking the biomass. Two different types of wheat straws were pretreated at varying temperatures and sizes. The results were compared with Buswell's equation for theoretical maximum biomethane yield. Compared to untreated straw, pre‐soaking leads to a significantly higher methane yield. Size reduction combined with light‐cooking does not affect the methane yield in the same manner as pre‐soaking of the biomass.     

Metal-coated magnetic nanoparticles for surface enhanced Raman scattering studies

We report the optimization and usage of surfactantless, water dispersible Ag and Au-coated g\boldsymbol\gamma–Fe₂_{\boldsymbol 2}O₃_{\boldsymbol 3} nanoparticles for applications in surface-enhanced Raman scattering (SERS). These nanoparticles, with plasmonic as well as super paramagnetic properties exhibit Raman enhancement factors of the order of 10⁶ (10⁵) for Ag (Au) coating, which are on par with the conventional Ag and Au nanoparticles. Raman markers like 2-naphthalenethiol, rhodamine-B and rhodamine-6G have been adsorbed to these nanoparticles and tested for nonresonant SERS at low concentrations. Further, to confirm the robustness of Ag-coated nanoparticles, we have performed temperature-dependent SERS in the temperature range of 77–473 K. The adsorbed molecules exhibit stable SERS spectra except at temperatures $\boldsymbol >$\boldsymbol >323 K, where the thermal desorption of test molecule (naphthalenethiol) were evident. The magnetic properties of these nanoparticles combined with SERS provide a wide range of applications.