Reliability modeling and performance evaluation of variablelink-capacity networks

This paper presents a composite performance index for communication networks with variable link-capacities. This index is based on link reliabilities and multiple-capacity link-states. Source-to-terminal success is the ability to provide connectivity with a certain traffic-carrying capacity. This index is useful for determining the performance of networks with links operating with residual traffic-carrying capacity and gives a good idea of the available resources for a particular s-t connection. An algorithm is given to evaluate the composite performance index     

Multisensor data fusion

Multisensor data fusion refers to the acquisition, processing and synergistic combination of information gathered by various knowledge sources and sensors to provide a better understanding of a phenomenon. It is a fascinating and rapidly evolving field that has generated a lot of excitement in the research and development community. These concepts are being applied to a wide variety of fields such as military command and control, robotics, image processing, air traffic control, medical diagnostics, pattern recognition and environmental monitoring. This paper presents a brief overview of the field and illustrates its potential by means of two examples     

Megha-Tropiques: mission planning,analysis, and operations

Climate in the tropics is primarily influenced by variations in energy and water budget exchanges in the land/ocean/atmosphere systems. The interaction of these systems with the general atmospheric circulation is still not fully understood – one of the reasons why weather forecasts and predictions of climatic events are less accurate. The Megha-Tropiques mission, an ISRO-CNES (Indian Space Research Organisation–Centre National d’Etudes Spatiales) collaborative programme, aims to study water cycle and energy exchanges in the tropics, and use the data in climate and meteorology models. Megha-Tropiques is part of the Global Precipitation Measurement Mission, which is an international network of satellites. Of the four payloads on board, MADRAS is jointly developed by ISRO and the French space agency, CNES; SAPHIR and SCARAB completely by CNES; and GPS-ROSA is obtained from TAS-I (Thales Alenia Space Italia, Milan, Italy). GPS-ROSA supplements the geophysical parameters of the other payloads for atmosphere modelling. Mission planning involved integrating and interrelating the efforts of space and ground systems in realizing the operational system that provides the satellite-based science data meeting the turnaround time (TAT). Pre-launch simulations involved usage of a software simulator as a tool for network tests, training of spacecraft operation personnel, and validating the spacecraft health-monitoring software. The required operations were performed to characterize the payloads as well as to calibrate the various attitude sensors of the spacecraft. This paper summarizes mission planning and analysis aiding spacecraft configuration, pre-launch mission simulations, launch and early-orbit operations, and the on-orbit operational guidelines for Megha-Tropiques.     

Characterization of copper nanoparticles synthesized by a novel microbiological method

The exploitation of various biomaterials for the biosynthesis of nanoparticles is considered as green technology as it does not involve any harmful chemicals. The present study reports the synthesis of copper nanoparticles which involves non-pathogenic bacterial strain Pseudomonas stutzeri, isolated from soil. These copper nanoparticles are further characterized for size and shape distributions by ultraviolet-visible spectroscopy, x-ray diffraction, and high resolution transmission electron microscopy techniques. The results showed that the particles are spherical and quite stable in nature and shows surface plasmon resonance clearly featured in the optical spectra in visible region.     

Effect of Curing and Functionalization on the Interface Thermal Conductance in Carbon Nanotube–Epoxy Composites

This study investigates the interface thermal conductance in a functionalized carbon nanotube (CNT)–epoxy composite system and how it is modified when the surrounding matrix is cured. We have used nonequilibrium molecular dynamics simulations to study the interface thermal conductance in both cured and uncured matrices, based on diglycidyl ether of bisphenol F (EPON-862) and diethylenetoluenediamine. The functionalization is modeled using a dynamic crosslinking algorithm and represents a realistic model of the matrix-filler interface. The thermal interface conductance increases linearly with the degree of functionalization up to the studied 2.5% due to stronger thermal coupling between functionalized CNT and the matrix. In addition, it was observed that curing of the matrix increases the interface conductance by 20% relative to the uncured matrix. This increase is attributed to an increase in thermal conductivity of cured epoxy resulting from relative enhancement in nonbonded interactions (originating from volume reduction) and structural rigidity during curing. Our results suggest that the interface conductance can be strongly influenced by the thermal properties of the bulk matrix as well as the interface chemistry of the additives such as CNTs.     

A Role for TGFβ Signaling in Preclinical Osteolytic Estrogen Receptor-Positive Breast Cancer Bone Metastases Progression

While tumoral Smad-mediated transforming growth factor β (TGFβ) signaling drives osteolytic estrogen receptor α-negative (ER-) breast cancer bone metastases (BMETs) in preclinical models, its role in ER+ BMETs, representing the majority of clinical BMETs, has not been documented. Experiments were undertaken to examine Smad-mediated TGFβ signaling in human ER+ cells and bone-tropic behavior following intracardiac inoculation of estrogen (E₂)-supplemented female nude mice. While all ER+ tumor cells tested (ZR-75-1, T47D, and MCF-7-derived) expressed TGFβ receptors II and I, only cells with TGFβ-inducible Smad signaling (MCF-7) formed osteolytic BMETs in vivo. Regulated secretion of PTHrP, an osteolytic factor expressed in >90% of clinical BMETs, also tracked with osteolytic potential; TGFβ and E₂ each induced PTHrP in bone-tropic or BMET-derived MCF-7 cells, with the combination yielding additive effects, while in cells not forming BMETs, PTHrP was not induced. In vivo treatment with 1D11, a pan-TGFβ neutralizing antibody, significantly decreased osteolytic ER+ BMETs in association with a decrease in bone-resorbing osteoclasts at the tumor-bone interface. Thus, TGFβ may also be a driver of ER+ BMET osteolysis. Moreover, additive pro-osteolytic effects of tumoral E₂ and TGFβ signaling could at least partially explain the greater propensity for ER+ tumors to form BMETs, which are primarily osteolytic.     

A KINETIC APPROACH TO EVALUATE THE ENERGY AND ENTROPY OF ACTIVATION FOR THE EXCHANGE OF ALKALINE EARTH METAL IONS ON TIN(IV) TUNGSTATE CATION EXCHANGER

Abstract

A new approach based on the Nernst-Planck equations has been applied to study the reaction kinetics on the surface of tin(IV) tungstate for the Mg(II)-H(I), Ca(II)-H(I), Sr(II)-H(I) and Ba(IT)-H(I) exchanges under the conditions favouring a particle diffusion phenomenon. On the basis of these studies the various physical parameters such as the effective diffusion coefficients, activation energies and entropies of activation have been evaluated which give some informations regarding the mechanism of ion-exchange on the surface of inorganic materials.     

Discrete Modeling of Growth of Hairy Roots in a Mist Bioreactor

Hairy root culture is a promising route for large‐scale secondary metabolite production. A discrete model is developed to study the kinetic growth of these valuable roots in a reactor. The growth process is defined to occur in three sequential phases. The elongation rate is modeled as exponential growth with the growth coefficient being dependent on mass transfer coefficient, nutrient concentration difference, and distribution of nutrients in growth and sustenance requirements. Results indicate that the primary root growth is reduced by one‐fifth of its initial growth rate due to the branching process, and the growth of new branches is significantly faster than its primary root growth due to internal transport of nutrients. The model is successfully validated against experimental findings. Its integration with spatio‐temporal variation of nutrients in a reactor will be a crucial input to large‐scale production of hairy roots.     

Application of nitrogen-enriched nanobiopolymer for the effective removal of Cr(VI) from tannery effluent

Nitrogen-enriched nanobiopolymer has been fabricated using (2,3-epoxypropyl) trimethylammonium chloride (EPTMAC) and explored for the removal of Cr(VI) from tannery effluent. The removal efficiency of nanobiopolymer was found to be 23.99 mg g^?1 (95.94%) under optimized conditions. The sorption data agrees well with the Langmuir and pseudo-second-order model. Equilibrium parameter (R_L) and sorption energy show the favorability and physical binding of Cr(VI) on the nanobiopolymer’s backbone. The values of ?G° (?7.84 kJ mol^?1), ?S° (65.97 J mol^?1K^?1) and ?H° (11.82 kJ mol^?1) reflect the feasible nature of the sorption process. Reusability study was also conducted to state the performance of the nanobiopolymer.