Stepwise Oxidation Mechanism of HVOF Sprayed NiCrAlY Coatings in Air

High velocity oxide fuel sprayed NiCrAlY coatings on the Superni 76 superalloy have been oxidized cyclically at 900 °C up to 200 cycles. Weight change measurements were taken after each cycle to obtain kinetics of the oxidation process. The surface and cross-section of oxidized samples have been examined by XRD, FESEM/EDS to characterize the corrosion products. The formation of Al₂O₃ at the surface as well as at the coating/scale interface as a sub-layer was observed. Other oxides such as Ni (Al, Cr)₂O₄ and Cr₂O₃ were also present above this Al₂O₃ sub-layer. An oxidation mechanism has been proposed for the oxidation of the coating for 200 cycles by correlating the results after different cycles of oxidation.     

Beneficiation studies on recovery and in-depth characterization of ilmenite from red sediments of badlands topography of Ganjam District,Odisha, India

This paper deals with the recovery of ilmenite mineral from red sediments of badlands topography and suggested flowsheet with material balance. The results of these investigations reveal that the red sediment samples contain 33.2% total heavy mineral, in which ilmenite mineral concentrate is 28.71% (by weight). The ilmenite concentrate recovered from red sediment sample by physical beneficiation process, which included scrubbing, desliming, gravity concentration, magnetic and electrostatic separation, contains 99.41% grade with 97.3% recovery. The ilmenite mineral concentrate recovered from red sediments is also suitable for industrial applications. The characterization studies on ilmenite reveal that the TiO₂ percentage is marginally increasing from 46.69% to 47.86% with increasing magnetic intensity from 0.46 to 1.55 T.     

Dynamic Modeling and Metabolic Flux Analysis for Optimized Production of Rhamnolipids

A comprehensive metabolic network based on the fundamental pathways representing the central metabolism of rhamnolipid by Pseudomonas aeruginosa is proposed and a dynamic model compatible with the underlying metabolic network is developed involving the macro-reactions derived from the elementary flux modes of the reaction network. The experimentally validated mathematical model is then coupled with a global optimization technique called differential evolution (DE) to optimize the medium composition as well as the extracellular and intracellular fluxes of the metabolic network. The analysis of the results shows the usefulness of the integrated approach involving the development of a dynamic model based on the metabolic network structure and model-based optimization of the medium composition and metabolic fluxes by an efficient evolutionary optimization technique to enhance the productivity of rhamnolipid.     

Energy Efficiency in Cognitive Radio Network Using Cooperative Spectrum Sensing

Wireless Personal Communications - In this paper, we consider an optimization of number of secondary users (SUs) in a cooperative spectrum sensing by maximizing the energy efficiency of the...     

Cluster‐based mobility management algorithms for wireless mesh networks

Wireless mesh networks (WMNs) have been the recent advancements and attracting more academicians and industrialists for their seamless connectivity to the internet. Radio resource is one among the prime resources in wireless networks, which is expected to use in an efficient way especially when the mobile nodes are on move. However, providing guaranteed quality of service to the mobile nodes in the network is a challenging issue. To accomplish this, we propose 2 clustering algorithms, namely, static clustering algorithm for WMNs and dynamic clustering algorithm for WMNs. In these algorithms, we propose a new weight‐based cluster head and cluster member selection process for the formation of clusters. The weight of the nodes in WMN is computed considering the parameters include the bandwidth of the node, the degree of node connectivity, and node cooperation factor. Further, we also propose enhanced quality of service enabled routing protocol for WMNs considering the delay, bandwidth, hopcount, and expected transmission count are the routing metrics. The performance of the proposed clustering algorithms and routing protocol are analyzed, and results show high throughput, high packet delivery ratio, and low communication cost compared with the existing baseline mobility management algorithms and routing protocols.     

Low Temperature Studies of Granularity and Upper Critical Field of Superconducting Nd<Subscript>1.85</Subscript>Ce<Subscript>0.15</Subscript>CuO<Subscript>4</Subscript>+Ag Composite System

Electrical resistivity studies reveal large granular effects in the superconductivity behaviour of the electron-doped cuprate, Nd_1.85Ce_0.15CuO₄, in polycrystalline form, much larger than their hole-doped counterparts. With the aim of investigating inter-granular coupling, as well as its variation with magnetic field and addition of Ag, AC susceptibility and magneto-resistance (MR) studies have been carried out on Nd_1.85Ce_0.15CuO₄ + Ag composite system. A comparative study of the superconducting properties of the Nd_1.85Ce_0.15CuO₄ + Ag composite system for Ag = 0, 5 and 15 wt%, including upper critical field [ H _C2(0)], has been carried out and is presented.     

Mimicking a hybrid-optomechanical system using an intrinsic quadratic coupling in conventional optomechanical system

We consider an optical and mechanical mode interacting through both linear and quadratic dispersive couplings in a general cavity-optomechanical set-up. The parity and strength of an intrinsic quadratic optomechanical coupling (QOC) provides an opportunity to control the optomechanical (OM) interaction. We quantify this interaction by studying normal-mode splitting (NMS) as a function of the QOC's strength. The proposed scheme exhibits NMS features equivalent to a hybrid-OM system containing either an optical parametric amplifier or a Kerr medium. Such a system in reality could offer an alternative platform for devising state-of-art quantum devices with requiring no extra degrees-of-freedom as in hybrid-OM systems.     

Realization of effective energy transfer and color tunability between Tb3+ and Eu3+ ions in LaAlO3 host for LED display applications

Journal of Materials Science: Materials in Electronics - By employing Polyol method, Tb3+ and Eu3+ co-doped LaAlO3 phosphors have been synthesized and the photoluminescence (PL), lifetime...     

Does the multi-authorship trend influence the quality of an article?

In the last few decades, multi-authored articles have increased in different disciplines with increasing instances of authorship abuse although multi-authorship is not always due to undeserving authorship (McDonald et al. in Mayo Clin Proc 85(10):920–927, 2010). It may be necessitated by interdisciplinary research, the evolution of a discipline, or the intention of quality improvement. This article studies the relationship between the authorship and the quality of articles (publications in better impact factor journals or core journals) in the field of Oceanography. The result shows ~75 % increase in the number of authors per article from 1990 to 2009 in the discipline. The increase in authorship correlates not only with the percentage of articles in core journals but also with the mean impact factor (IF) of journals (where the articles were published). The ANOVA study shows that though multi-authorship has no influence on the preference to publish in core journals during the 1990s or 2000s, it does have a significant influence on the preference to publish in high IF journals in both the decades. So these findings establish that in the field of Oceanography, the increase in collaboration would have resulted in more publications in core journals (without any influence of authorship increase) and in better impact factor journals (due to the influence of authorship increase).     

Automated Controller Placement for Software-Defined Networks to Resist DDoS Attacks

In software-defined networks (SDNs), controller placement is a critical factor in the design and planning for the future Internet of Things (IoT), telecommunication, and satellite communication systems. Existing research has concentrated largely on factors such as reliability, latency, controller capacity, propagation delay, and energy consumption. However, SDNs are vulnerable to distributed denial of service (DDoS) attacks that interfere with legitimate use of the network. The ever-increasing frequency of DDoS attacks has made it necessary to consider them in network design, especially in critical applications such as military, health care, and financial services networks requiring high availability. We propose a mathematical model for planning the deployment of SDN smart backup controllers (SBCs) to preserve service in the presence of DDoS attacks. Given a number of input parameters, our model has two distinct capabilities. First, it determines the optimal number of primary controllers to place at specific locations or nodes under normal operating conditions. Second, it recommends an optimal number of smart backup controllers for use with different levels of DDoS attacks. The goal of the model is to improve resistance to DDoS attacks while optimizing the overall cost based on the parameters. Our simulated results demonstrate that the model is useful in planning for SDN reliability in the presence of DDoS attacks while managing the overall cost.