Chalcogenide nanocomposite electrodes grown by chemical etching of Ni-foam as electrocatalyst for efficient oxygen evolution reaction

We report on the synthesis of NiSSe nanocomposite by chemical etching of Ni-foam using simple solvothermal technique and investigated it as an electrocatalyst for the oxygen evolution reaction (OER). Different morphologies such as nanograins, branched mesh-like architecture, and agglomerated nanograins with nanoporous are obtained for NiSSe, NiSe, and NiS, respectively. The overpotentials of 247, 266, and 329 mV (vs RHE) are obtained to attain a current density of 30 mA cm⁻² for NiSSe, NiS, and NiSe nanocomposites, respectively. Interestingly, ternary nanocomposite reaches a high current density of 100 mA cm⁻² by operating only at an overpotential of 342 mV. The low Tafel slope of 175.7 mV dec⁻¹ reveals that the ternary nanocomposite consists of most favorable catalytic kinetics for mass and electron transport during the OER reaction. The improved catalytic performance of NiSSe nanocomposite is attributed to the synergy between electrochemcial surface area and improved electronic conductivity.     

Knowledge work and communication challenges in networked enterprises

A modern enterprise is a heavily wired and networked socio-technical system where multiple components play in symphony to yield a competitive position in the ear of digital economy. While the underling communication and interaction systems facilitate knowledge workers to carry out the enterprise mission and furnish service to the society, there are many other aspects that rather have adverse effects on the productivity of an enterprise and interruption of knowledge workers, which pose a serious scientific challenge. In this paper, we briefly discuss certain challenging aspects of knowledge work and communication processes in networked enterprises that require more profound scientific attention in networked enterprises. This paper introduces the problem, identifies some specific research challenges, and then briefly discusses emerging research that addresses some of these challenges.     

Corrosion of carbon-alloyed iron aluminides

The corrosion behaviour of two carbon-alloyed intermetallics of composition Fe-28.1Al-2.1C and Fe-27.5Al-3.7C has been studied and compared with that of binary intermetallics. Potentiodynamic polarization studies indicated that the intermetallics exhibited active-passive behaviour in an acidic solution of pH = 1, whereas they exhibited stable passivity in a buffer solution of pH 8.4. Corrosion rates were also obtained by immersion testing. The variation of corrosion rate as a function of time was similar for both the intermetallics. The variation in corrosion rate as a function of time has been explained based on the observed potentiodynamic polarization behaviour. Scanning electron microscopy of corroded surfaces indicated that the carbon-alloyed intermetallics were susceptible to galvanic corrosion, due to the presence of carbides.     

Influence of Sputtering Pressure on the Structure and Mechanical Properties of Nanocomposite Ti-Si-N Thin Films

Nanocomposite Ti-Si-N thin films have been deposited on Si (100) substrate by direct current/radio frequency (DC/RF) magnetron sputtering. The effect of varying deposition parameters on the structure and mechanical properties of Ti-Si-N films has been investigated by characterization techniques such as X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and nanoindentation, respectively. XRD analysis of the thin films exhibit all (111), (200) and (220...     

Biographies of Contributors

This paper reports a method to automatically solve simple substitution ciphers where the message length is about 160 characters and the space character is suppressed during encryption. Patterns available in the crypt are used as opening points. With the help of a dictionary system, words are fitted at these points after suitable filtering. Subsequently, a tuple generator-cum-selector is used to select a meaningful tuple of words for decoding the crypt. During test runs, 70 out of 100 randomly chosen messages were solved to as sufficient a degree as to facilitate manual completion. Manual completion was found to be fairly simple when the algorithm had correctly identified 70 percent or more of the character positions. The time required for the algorithm to reach this stage was, on an average, about twenty minutes on a standard personal computer.     

Evidence and Long-Term Feasibility of Enhanced Biological Phosphorus Removal in Oxidation-Ditch Type of Aerated-Anoxic Activated Sludge Systems

This study investigated the potential of four full-scale oxidation ditches to accomplish enhanced biological phosphorus removal (EBPR). Despite the fact that none of the tested oxidation ditches were designed to perform EBPR, mixed liquors from all four ditches showed good specific phosphorus release and uptake rates, a typical characteristic of a typical EBPR biomass. The specific phosphorus release rates ranged from 0.042- to 0.254-mg P/mg VSS-d and the specific phosphorus uptake rates ranged from 0.023- to 0.125-mg P/mg VSS-d for the tested full-scale plants. The EBPR potential of one of the full-scale plants (Central Davis Sewer District) was further studied by changing the aeration patterns in the ditch. The mixed liquor in this full-scale plant exhibited good phosphorus release and uptake trends and dissolved phosphorus, as low as 1.26 mg/L, could be accomplished in the final effluent of this plant as a result of this optimization. The long-term feasibility of the EBPR in this full-scale was tested by running a bench-scale EBPR reactor, in which the anaerobic phase was replaced with aerated-anaerobic phase to simulate the mixed liquor environment that exists in Central Davis mixed liquor and, in general, in all oxidation-ditch-type activated sludge configurations. The bench-scale reactor showed consistent EBPR activity in the absence of an anaerobic environment and more than 85% phosphorus removal could be maintained in the reactor for more than 400 days. The intrafloc microanaerobic/anoxic zones, which may be present in the mixed liquor, did not seem to add to the EBPR efficiency under aerated-anaerobic conditions. Cloning and sequencing using Rhodocyclus specific forward primer RHC439 showed the abundance of organisms most closely falling in Rhodocyclaceae family but not related to Candidatus Accumulibacter phosphatis. Simultaneous 4′-6–Diamidino-2–phenylindole (DAPI) staining and fluorescent in situ hybridization (FISH) using RHC439 probe clearly demonstrated the participation of polyphosphate accumulating organism (PAOs) targeted by RHC439 (i.e., in Rhodocyclaceae family). Microautoradiography assisted FISH using RHC439 further confirmed the participation of PAOs in Rhodocyclaceae family.     

Microencapsulation of doxycycline into poly(lactide-co-glycolide) by spray drying technique: Effect of polymer molecular weight on process parameters

Poly(lactide-co-glycolide) (PLGA) polymers with three different molecular weights were prepared, and microparticles were produced by spray drying and water-in-oil-water (w/o/w) double emulsion techniques to encapsulate 86% of doxycycline (DXY), an antibiotic drug, for the use of periodontitis. Placebo and drug-loaded microspheres and pristine DXY were analyzed by Fourier transform infrared spectroscopy, which indicated no chemical interactions between DXY and PLGA. X-ray diffraction of drug-loaded microspheres confirmed the molecular level dispersion of DXY in PLGA. Scanning electron microscopy confirmed spherical nature and smooth surfaces of the microspheres. Mean particle size as measured by laser light scattering technique ranged between 10 and 25 μm. In vitro release of DXY performed in 7.4 pH media continued up to 72 h and depended on molecular weight of PLGA and extent of DXY loading. Antimicrobial studies performed on one formulation and placebo microspheres suggested that drug concentrations during in vitro release are above the minimum inhibitory concentration (MIC) for Staphylococcus aureus growth. Overall, the release studies depended on the molecular weight of PLGA, extent of drug loading, and the method used to prepare microspheres. Statistical analyses of release data performed using the analysis of variance (ANOVA) method agreed well with experimental observations. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Hygrothermoelastic Postbuckling Response of Laminated Composite Plates

The paper deals with the effect of moisture and temperature on the postbuckling response of a laminated composite plate subjected to hygrothermomechanical loadings. Mechanical loading consists of uniaxial, biaxial, shear, and their combinations. The distribution of temperature and moisture on the surface is considered to be uniform. The degradation in material properties due to moisture and temperature is taken into account using a micromechanical model. The mathematical formulation is based on higher order shear deformation theory and von Karman’s nonlinear kinematics. The quadratic extrapolation technique and fast converging finite double Chebyshev series are used for linearization and spatial discretization of the governing nonlinear equations of equilibrium, respectively. The effects of temperature rise, moisture concentration, fiber-volume fraction, and plate parameters on buckling and postbuckling response of the plate are presented.