Hot Corrosion Behavior of Some Superalloys in a Simulated Incinerator Environment at 900 °C

Incinerators are being used to burn solid waste of all types. This burning of waste creates a very aggressive environment at extremely high temperature. This environment attacks the various components of the incinerators. Some studies have been reported regarding behavior of steels in simulated incinerator environment at 550 °C. In present work superalloys Superco 605, Superni 600, and Superni 718 have been subjected to cyclic oxidation in 40 wt.% K₂SO₄ + 40 wt.% Na₂SO₄ + 10 wt.% KCl + 10 wt.% NaCl environment at 900 °C under cyclic condition. Weight change measurements have been done and weight change has been plotted against the numbers of cycles. The oxide scales formed on the surface of the corroded superalloys have been characterize by FESEM, EDS, XRD, cross-sectional analysis, and x-ray mapping. The nickel-based superalloys Superni 600 and Superni 718 indicated better resistance to corrosion in the above environment whereas Superco 605 lead to massive weight gain.     

Cryptococcus neoformans: historical curiosity to modern pathogen

The importance of the Basidiomycete Cryptococcus neoformans to human health has stimulated its development as an experimental model for both basic physiology and pathogenesis. We briefly review the history of this fascinating and versatile fungus, some notable aspects of its biology that contribute to virulence, and current tools available for its study. Copyright © 2013 John Wiley & Sons, Ltd.     

Growth of anthraquinone crystals by gel aided solution technique and their characterization

Anthraquinone, an oxidation product of anthracene, has been grown by gel aided solution technique employing sodium metasilicate. Needle shaped crystals were obtained in 0–5% (w/v) solution of anthraquinone for pH 5-5. The grown crystals were characterized by optical microscopy, SEM, IR, UV and XRD.     

The challenge of non-ergodicity in network neuroscience

Ergodicity can be assumed when the structure of data is consistent across individuals and time. Neural network approaches do not frequently test for ergodicity in data which holds important consequences for data integration and intepretation. To demonstrate this problem, we present several network models in healthy and clinical samples where there exists considerable heterogeneity across individuals. We offer suggestions for the analysis, interpretation, and reporting of neural network data. The goal is to arrive at an understanding of the sources of non-ergodicity and approaches for valid network modeling in neuroscience.     

Two-Gap Superconductivity in Niobium Carbide-Coated Single-Walled Carbon Nanotubes: A First-Principles Study

Superconductivity in carbon nanotubes is attracting worldwide attention because of the reported high superconducting transition temperature in small-diameter single-walled carbon nanotubes (SWCNTs). However, it is well known that superconductivity in low-dimensional (quasi-1D) systems is not so common due to low density of states (DOS), strong quantum fluctuations and other phenomena in such systems. In this paper, we present theoretical investigations of the proximity effect of superconducting niobium carbide on single-walled carbon nanotube using density functional theory (DFT). The relaxed structure shows that Nb atoms are held around the SWCNT, forming a layer through weak van der Waals’ forces. The stability of the structure has been confirmed by Hirshfeld analysis and Mullikan population analysis as well. The study of the electronic band structure of the pristine and modified SWCNT shows a fascinating condensation of electronic states and a striking shift in the Fermi level. Further, two additional band gaps have appeared below the valence band suggesting some kind of pairing mechanism being operational. This indicates the possibility of superconducting behaviour in SWCNT in proximity of niobium carbide. The relaxed structure thus envisions the feasibility and stability of NbC-coated SWCNTs which will have superconducting properties as well as the remarkable mechanical and optical properties of SWCNTs. This prediction seeks interest of the researchers to try and develop such a novel nanomaterial which, if realized, will prove to be highly significant for many technological applications.     

Performance Evaluation of Polar Coded Filtered OFDM for Low Latency Wireless Communications

Wireless Personal Communications - The fifth generation new radio (5G-NR) system design is aimed to have ultra-large transmission rate, massive capacity, massive device connectivity, enhanced...     

Design of a Guitar Shaped UWB Antenna with Wide Band Notched Characteristics for Wireless Applications

Cloud storage is a cloud based service which delivers scalable on demand on line storage of data and eliminates the need of maintaining local data centre. Storage of data in cloud brings many advantages such as lower-cost, metered service, scalable and ubiquitous access. However, it also raises concerns to its integrity; to save the storage space cloud service provider may delete some rarely access data. Data privacy is another issue which must be addressed to increase data owner’s trust. To address above issues, many researchers have proposed public auditing schemes to validate the integrity of data using third party auditor. These schemes generate metadata using data files on the owner side and store these metadata on the cloud storage along with the file data, which helps in auditing. These schemes address many concerns which arise due to remote data storage. However, computation cost involved for metadata generation at the data owner side is not properly addressed; another issue which is not properly addressed is an iniquitous third party auditor may be the source of denial of service attack by issuing constantly large number of audit request. Our scheme solves these issues by lowering the computation cost at data owner side and controlling the number of times a third party auditor can issue an audit request to the cloud storage. Our Scheme also supports secure access of data using conditional proxy re-encryption scheme and delegation of auditing task by the authorized third party auditor to another auditor for the specified period of times in the case of unavailability of authorized third party auditor.

     

Performance Analysis of Digitized Orthogonal Frequency Division Multiplexing System for Future Wireless Communication

Wireless Personal Communications - Optical wireless communication (OWC) in the infrared and visible range is an appealing technology, principally in environment arenas where radio communication...     

Synthesis and electrochemical properties of blend membranes of polysulfone and poly (acrylic acid-co-2-(2-(piperazin-1-yl) ethylamino)-2-hydroxyethyl methacrylate) for proton exchange membrane fuel cell

In this work, new piperazine containing copolymer membrane was developed from acrylic acid and 2-(2-(piperazin-1-yl)ethylamino)-2-hydroxyethyl methacrylate through free radical polymerization method by means of AIBN as an initiator, in bulk. The monomer feed ratio was varied to obtain various copolymers having a different composition. The developed copolymer was blended in polysulfone (PSF) at 3 and 6 wt% using N,N′-Dimethylformamide solvent. The FTIR spectra and 1H NMR spectral data have proved the presence of copolymer that has hydrophilic functional group which influences the better proton conductivity. The membranes were characterized by their morphology using scanning electron microscope and x-ray diffraction analysis. The hydrophilic nature of the membranes is proved through high water uptake ratio. The exchangeable proton at the carboxylic acid group has enhanced the high ion exchange capacity. The blend membranes have higher water uptake, low swelling rate and higher ion exchange capacity than that of neat PSF membrane. The fabrication of fuel cell and studies on proton exchange capacity indicates that the prepared membranes have proton conductivity of as high as 8.77 × 10^?4 S cm^?1. Low methanol crossover was obtained about 2.112 × 10^?6 cm²s^?1 when compared to the pristine membrane.     

Effect of neodymium doping on structural,electrical and magnetic properties of multiferroic GdMn<Subscript>2</Subscript>O<Subscript>5</Subscript>

Neodymium doped gadolinium manganate with general composition (Nd_0.1Gd_0.9Mn₂O₅) was prepared by co-precipitation method. Microstructural and compositional analysis has been carried out by X-ray diffraction and scanning electron microscopy. The optical studies have been carried out by Raman and FTIR. The electrical properties studied include dielectric constant, dielectric loss, ac conductivity and activation energy in the temperature range 20–400 ?°C. The shift in the dielectric peak towards higher temperature side with increasing frequency indicates frequency dispersion and suggesting the relaxational behaviour of the material. Frequency dependence of ac conductivity obeys the universal power law. The value of activation energy depends on increase in frequency. The room temperature magnetic behaviour has been analyzed from the magnetic field dependent magnetization curve. The grown material exhibits the paramagnetic behavior at room temperature.