Electro-precipitation of magnetite nanoparticles: an electrochemical study

Nanoparticles of magnetites (Fe3O4) are synthesized with a new process based on electro-precipitation in ethanol medium. A mechanism pathway is proposed consisting of a Fe(OH)3 precipitation followed by the reduction of iron hydroxide to magnetite in the presence of hydroxyl ions which are enerated at the cathode

A new battery-charging method suggested by molecular dynamics simulations

Based on large-scale molecular dynamics simulations, we propose a new charging method that should be capable of charging a Lithium-ion battery in a fraction of the time needed when using traditional methods. This charging method uses an additional applied oscillatory electric field. Our simulation results show that this charging method offers a great reduction in the average intercalation time for Li+ ions, which dominates the charging time. The oscillating field not only increases the diffusion rate of Li+ ions in the electrolyte but, more importantly, also enhances intercalation by lowering the corresponding overall energy barrier.Comment: 11 pages, 5 figure

Examining the Roles of Parent–Child and Teacher–Child Relationships on Behavior Regulation of Children at Risk

The current study examined the effects of parent–child and teacher–child relationships on behavior regulation of children at risk. In particular, the amplifying or attenuating effect of one context (i.e., teacher–child relationships) for another context (i.e., parent–child relationship) on children’s behavior regulation was examined. Participants were 291 children (159 boys) ages 37–70 months (M = 53.88 months, SD = 6.44 months) from three different preschools serving low-income children in two Midwestern cities. Parents and teachers reported on their relationships with children during fall. Behavior regulation was assessed via structured tasks during spring and summer. After controlling for demographic variables, results showed that parent–child closeness and teacher–child conflict were related to children’s behavior regulation. Interaction models showed that when children experienced a combination of low parent–child closeness and high teacher–child conflict, they had lower levels of behavior regulation. Findings highlight the importance of parent–child and teacher–child relationships, both independently and together, for low-income children’s behavior regulation

Chemoselective hydrogenation of arenes by PVP supported Rh nanoparticles

Polyvinylpyrrolidone-stabilized Rh nanoparticles (RhNPs/PVP) of ca. 2.2 nm in size were prepared by the hydrogenation of the organometallic complex [Rh(η3-C3H5)3] in the presence of PVP and evaluated as a catalyst in the hydrogenation of a series of arene substrates as well as levulinic acid and methyl levulinate.</p

A model-based hybrid approach for circuit breaker prognostics encompassing dynamic reliability and uncertainty

Prognostics predictions estimate the remaining useful life of assets. This information enables the implementation of condition-based maintenance strategies by scheduling intervention when failure is imminent. Circuit breakers are key assets for the correct operation of the power network, fulfilling both a protection and a network reconfiguration role. Certain breakers will perform switching on a deterministic schedule, while operating stochastically in response to network faults. Both types of operation increase wear on the main contact, with high fault currents leading to more rapid ageing. This paper presents a hybrid approach for prognostics of circuit breakers, which integrates deterministic and stochastic operation through Piecewise Deterministic Markov Processes. The main contributions of this paper are (i) the integration of hybrid prognostics models with dynamic reliability concepts for a more accurate remaining useful life forecasting and (ii) the uncertain failure threshold modelling to integrate and propagate uncertain failure evaluation levels in the prognostics estimation process. Results show the effect of dynamic operation conditions on prognostics predictions and confirm the potential for its use within a condition-based maintenance strategy

Demonstration of CoWDM using DPSK modulator array with injection-locked lasers

A practical implementation of coherent wavelength division multiplexing (CoWDM) is demonstrated for the first time using injection-locked lasers and a DPSK modulator array. For a 31.99 Gbit/s system (three subcarriers at 10.664 Gbit/s) the null-to-null spectral bandwidth was only 42.656 GHz and the average receiver sensitivity measured was -33.5 dBm when all subcarrier phases were optimised

Anisotropic pressure in dense neutron matter under the presence of a strong magnetic field

Dense neutron matter with recently developed BSk19 and BSk21 Skyrme effective forces is considered in magnetic fields up to $10^{20}$ G at zero temperature. The breaking of the rotational symmetry by the magnetic field leads to the differentiation between the pressures along and perpendicular to the field direction which becomes significant in the fields $H>H_{th}\sim10^{18}$ G. The longitudinal pressure vanishes in the critical field $10^{18}<H_c\lesssim10^{19}$ G, resulting in the longitudinal instability of neutron matter. For the Skyrme force fitted to the stiffer underlying equation of state (BSk21 vs. BSk19) the threshold $H_{th}$ and critical $H_c$ magnetic fields become larger. The longitudinal and transverse pressures as well as the anisotropic equation of state of neutron matter are determined under the conditions relevant for the cores of magnetars.Comment: 7 pages, 3 figures; published online 7 December 201

PMD tolerance of 288 Gbit/s Coherent WDM and transmission over unrepeatered 124 km of field-installed single mode optical fiber

Low-cost, high-capacity optical transmission systems are required for metropolitan area networks. Direct-detected multi-carrier systems are attractive candidates, but polarization mode dispersion (PMD) is one of the major impairments that limits their performance. In this paper, we report the first experimental analysis of the PMD tolerance of a 288Gbit/s NRZ-OOK Coherent Wavelength Division Multiplexing system. The results show that this impairment is determined primarily by the subcarrier baud rate. We confirm the robustness of the system to PMD by demonstrating error-free performance over an unrepeatered 124km field-installed single-mode fiber with a negligible penalty of 0.3dB compared to the back-to-back measurements. (C) 2010 Optical Society of Americ