Iron molybdates as electrocatalysts for O2 evolution reaction in alkaline solutions

Iron molybdates with [Mo]/[Fe] ratios 1.0, 1.5 and 3.0 have been prepared by a co-precipitation method and produced in the form of thin films on a Ni support. These oxides follow the monoclinic crystal geometry. The study shows that the new oxide is highly active towards the oxygen evolution reaction in alkaline solutions and that its activity seems to depend upon the molar ratio of Mo and Fe in the oxide. The oxide with [Mo]/[Fe] = 1.0 is observed to exhibit the greatest electrocatalytic activity. The reaction order with respect to OH⁻ concentration has been found to be fractional (0.8–1.6). The Tafel slopes at low potentials were close to 35 mV.     

Corrosion Characteristics of Ni-Based Hardfacing Alloy Deposited on Stainless Steel Substrate by Laser Cladding

Metallurgical and Materials Transactions A - In this study, corrosion characteristics of a nickel-based Ni-Mo-Cr-Si hardfacing alloy having 32Mo, 15Cr, and 3Si (wt pct) as alloying...     

Studies on sacrificial and carbon deoxidation of niobium

The nature and extent of oxygen removal from Nb–C–O alloys on heating to 2273 K under 2 mPa vacuum has been investigated. Correlations have been given relating the vapour pressure ratios of CO, NbO(v) and NbO₂(v) to the residual oxygen and carbon contents in niobium and the temperature of treatment. Experimental results of treating Nb pellets with initial oxygen content of 1.09 wt% and added carbon corresponding to C/O ratios of 0–1.10 in a thermogravimetry unit up to 2273 K under 2 mPa have been explained on the basis of the relevant vapour pressure ratios. The deoxidation of Nb–C–O begins at 1650 K and proceeds in three distinct steps consisting of both sacrificial deoxidation and carbon deoxidation. The first step is sacrificial deoxidation due to formation of NbO₂(v), the second step is carbon deoxidation, and the final step is sacrificial deoxidation by NbO(v) vaporization. The extent of deoxidation in each of these steps depends on C/O ratio of the charge.     

Broadening of Photonic Band Gap in a One—Dimensional Superconductor Star Waveguide Structure

The present paper describes the theoretical investigation of enlarged reflection bands (photonic band gaps) in a 1D star waveguide (SWG) structure consists of superconductor and dielectric as its constituent materials. For the present study, we take the different combinations of superconductor and dielectric materials as a backbone and side branches of the SWG structure. In order to obtain the dispersion relation, Interface Response Theory (IRT) has been employed. Photonic band gaps of SWG structure having superconductor?Csuperconductor, superconductor?Cdielectric, and dielectric?Csuperconductor materials are compared with the band gaps of the conventional photonic crystal (PC) structure having superconductor?Csuperconductor and dielectric?Csuperconductor materials. Analysis of the dispersion characteristics shows that there exists no band gaps for conventional PC when both layers are made of the same superconducting materials (as the usual case) while the SWG structure shows forbidden bands of finite width even the backbone and side branches are made of same materials. Also, the SWG structure having superconductor?Cdielectric shows the wider reflection bands in comparison with the structure having dielectric?Csuperconductor as its constituent materials, while for the conventional PC structure it is same in both the cases. Further, the effect of temperature and the effect of variation of number of grafted branches on the photonic bands of SWG structure have been studied.     

Viscous Potential Flow Analysis of Nonlinear Rayleigh–Taylor Instability with Heat and Mass Transfer

The nonlinear analysis of Rayleigh?CTaylor instability of two viscous fluids is studied when there is heat and mass transfer across the interface, using viscous potential flow theory. The fluids are considered to be viscous and incompressible with different kinematic viscosities. The analysis is based on the method of multiple scale perturbation and the nonlinear stability is governed by first-order nonlinear partial differential equation. The stability conditions are obtained and stability is discussed theoretically as well as numerically. Regions of stability and instability have been shown graphically indicating the effect of various parameters. It has been observed that the heat and mass transfer has stabilizing effect on the stability of the system in the nonlinear analysis.     

Mechanisms of anticarcinogenic properties of curcumin: the effect of curcumin on glutathione linked detoxification enzymes in rat liver

Clinicians lack a practical method for measuring CBF rapidly, repeatedly, and noninvasively at the bedside. A new noninvasive technique for estimation of cerebral hemodynamics by use of near-infrared spectroscopy (NIRS) and an intravenously infused tracer dye is proposed. Kinetics of the infrared tracer indocyanine green were monitored on the intact skull in pigs. According to an algorithm derived from fluorescein flowmetry, a relative blood flow index (BFI) was calculated. Data obtained were compared with cerebral and galeal blood flow values assessed by radioactive microspheres under baseline conditions and during hemorrhagic shock and resuscitation. Blood flow index correlated significantly (rs = 0.814, P < 0.001) with cortical blood flow but not with galeal blood flow (rs = 0.258). However, limits of agreement between BFI and CBF are rather wide (+/- 38.2 +/- 6.4 mL 100 g-1 min-1) and require further studies. Data presented demonstrate that detection of tracer kinetics in the cerebrovasculature by NIRS may serve as valuable tool for the noninvasive estimation of regional CBF. Indocyanine green dilution curves monitored noninvasively on the intact skull by NIRS reflect dye passage through the cerebral, not extracerebral, circulation.     

New ternary mixed oxides of Fe, Ni and Mo for enhanced oxygen evolution

Ternary mixed oxides of Fe, Ni and Mo with molecular formulas Fe_xNi_1−xMoO₄ (x = 0.25, 0.50 and 0.75) have been prepared by a co-precipitation method and investigated for their structural and electrocatalytic properties by XRD, AFM, electrochemical impedance spectroscopy and anodic Tafel polarization. Results indicate that the apparent oxygen evolution activity of the base (NiMoO₄) electrode significantly increases with introduction of Fe from 0.25 to 0.75 mol. The Tafel slope for the oxygen evolution reaction at low overpotentials is found to be only ∼35 mV on Fe-substituted oxides, while it was ∼75 mV on the base oxide. The reaction follows the first order kinetics with respect to OH⁻ concentration, regardless of Fe content in the oxide.     

Managing Data Placement in Memory Systems with Multiple Memory Controllers

Modern processors such as Tilera’s Tile64, Intel’s Nehalem, and AMD’s Opteron are migrating memory controllers (MCs) on-chip, while maintaining a large, flat memory address space. This trend to utilize multiple MCs will likely continue and a core or socket will consequently need to route memory requests to the appropriate MC via an inter- or intra-socket interconnect fabric similar to AMD’s HyperTransport^TM, or Intel’s Quick-Path Interconnect^TM. Such systems are therefore subject to non-uniform memory access (NUMA) latencies because of the time spent traveling to remote MCs. Each MC will act as the gateway to a particular region of the physical memory. Data placement will therefore become increasingly critical in minimizing memory access latencies. Increased competition for memory resources will also increase the memory access latency variation in future systems. Proper allocation of workload data to the appropriate MC will be important in decreasing the variation and average latency when servicing memory requests. The allocation strategy will need to be aware of queuing delays, on-chip latencies, and row-buffer hit-rates for each MC. In this paper, we propose dynamic mechanisms that take these factors into account when placing data in appropriate slices of physical memory. We introduce adaptive first-touch page placement, and dynamic page-migration mechanisms to reduce DRAM access delays for multi-MC systems. We also introduce policies that can handle data placement in memory systems that have regions with heterogeneous properties. The proposed policies yield average performance improvements of 6.5% for adaptive first-touch page-placement, and 8.9% for a dynamic page-migration policy for a system with homogeneous DRAM DIMMs. We also show improvements in systems that contain DIMMs with different performance characteristics.     

Evaluation of carsharing network’s growth strategies through discrete event simulation

Carsharing organizations are nowadays faced with the emergence of new markets due to the growing popularity of their services. To keep up with the growing demand, they have to constantly adapt their network and balance their stations’ capacities by implementing new strategies. These strategies involve creation of new carsharing stations, increasing the capacity of stations, merging or demerging carsharing stations etc. Currently, the decision makers rely on an intuitive strategy selection process which often results in inadequate decisions being made representing an immediate loss in resources, time and market penetration. This paper presents a discrete event simulation based decision support tool that assists the decision makers in selecting best network growth strategies to implement for meeting adequately the demand growth while maximizing the members’ satisfaction level and minimizing the number of vehicles used. Our discrete event simulation model allows modeling the activities at any given set of carsharing stations, regardless of their number and capacities. A benchmarking comparison of different potential strategies is done. An application of the proposed model on a region of Communauto’s Montréal (Québec, Canada) carsharing network is provided.