Advanced all-optical logic gates on a spectral bus

We present experimental results on a new method for ultrafast all-optical logic, which utilizes four-wave mixing on polarization-modulated signals. The technique allows advanced operations such as exclusive-or and three-bit addition with carry bit. Furthermore, we show that on-the-fly error-correction encoding and decoding of a simple Hamming code is achieved when these gates are used on the bits of a spectrally structured word. These gates may be suitable for logic operations in an optoelectronic front end, which moves some of the necessary computation of data to the optical domain, before detection.     

Excess Molar Volumes and Viscosities of Mixtures of Diethylene Glycol Dibutyl Ether with Dialkyl Carbonates at 298.15, 308.15, and 318.15 K

Excess molar volumes,V ^E _m, and viscosities,, were measured as a function of composition for the binary mixtures of diethylene glycol dibutyl ether+dimethyl carbonate, +diethyl carbonate, and +propylene carbonate at temperatures of 298.15, 308.15, and 318.15 K and atmospheric pressure over the whole range of mixture compositions. From the experimental results, deviations in the viscosity,ln, and excess free energies of activation of viscous flow,G*^E, were calculated. The experimental results were correlated using the Redlich–Kister equation. The experimental and calculated quantities were used to analyze the mixing behavior of the components. Furthermore, activation enthalpies,H*, and entropies,S*, of viscous flow were evaluated and their variation with concentration is discussed.     

On the Performance of a Two-User MIMO Downlink System in Heavy Traffic

A multiple-input multiple-output (MIMO) downlink system in which data is transmitted to two users over a common wireless channel is considered. The channel is assumed to be fixed for all transmissions over the period of interest and the ratio of anticipated average arrival rates for the two users, also known as the relative traffic rate, is the system design parameter. A packet-based traffic model is considered where data for each user is queued at the transmit end. A queueing analog for this system leads to a coupled queueing system for which a simple policy is known to be throughput-optimal under Markovian assumptions. Since an exact expression for the performance is not available, as a measure of performance (in heavy traffic), a diffusion approximation is established. This diffusion process is a two-dimensional (2-D) Semimartingale Reflecting Brownian Motion (SRBM) living in the positive quadrant of 2-D space     

A computational method for regularized long wave equation

Quintic spline technique and splitting method have been used to develop a new-finite difference method to solve regularized long wave (RLW) equation. The convergence and the stability of the proposed method are discussed. Then, it is used to model solitary wave motion and undular bore development by solving two test examples.     

Neither L-arginine nor L-NAME affects neurological outcome after global ischemia in cats

BACKGROUND AND PURPOSE: We attempted to determine whether N-nitro-L-arginine methyl ester (L-NAME) would improve neurological outcome and whether L-arginine (L-ARG) would worsen neurological outcome after transient global ischemia. METHODS: Halothane-anesthetized cats (n = 6 for each group) were treated with intravenous saline, L-NAME (5 mg/kg or 10 mg/kg), or L-arginine (300 mg/kg) 30 minutes before 10 minutes of ischemia (temporary ligation of the left subclavian and brachiocephalic arteries with hemorrhagic hypotension to 50 mm Hg). At 30 minutes of reperfusion, cats in the L-ARG group were administered an additional 300 mg/kg dose of intravenous L-arginine. RESULTS: Time (mean +/- SE) to isoelectric electroencephalography was similar among groups (saline, 26 +/- 11 seconds; L-NAME-5, 15 +/- 4 seconds; L-NAME-10, 36 +/- 27 seconds; and L-ARG, 22 +/- 7 seconds). At 72 hours, reperfusion pathological injury was severe and neurological deficit score (mean, range) was similar among groups (saline, 38[11 to 70]; L-NAME-5, 52 [40 to 73]; L-NAME-10, 47 [23 to 70]; and L-ARG, 40 [0 to 79]). CONCLUSIONS: Nitric oxide is not important in the mechanism of brain injury after global ischemia in cats.     

Uncoupled non-linear equations method for determining kinetic parameters in case of hydrogen evolution reaction following Volmer–Heyrovsky–Tafel mechanism and Volmer–Heyrovsky mechanism

Hydrogen evolution reaction following Volmer–Heyrovsky–Tafel mechanism and not under diffusion control can be characterized using Tafel polarization and alternating current admittance data at various frequencies and at various overpotentials. Such reaction has four independent kinetic parameters. One empirical constant related to charge required for complete surface coverage is also involved.

In case of systems where only one time constant (related to charging/discharging of electrical double layer) is discerned, Volmer–Heyrovsky mechanism is assumed. Such systems have three independent kinetic parameters. Experimental data may provide maximum two independent conditions at a less cathodic overpotential and maximum one independent condition at a more cathodic overpotential.

A new approach to determine kinetic parameters utilizing these data and neglecting Heyrovsky and Tafel backward reaction rates has been proposed. The conditions involved are coupled non-linear equations. Uncoupled non-linear equations have been derived and iterated using Newton–Raphson method. The approach has been validated using literature data. The graphical relationships between experimental parameters and kinetic parameters have also been shown.     

Simplified loss analysis and comparison of full-bridge,full-range-ZVS DC-DC converters

The loss of zero-voltage-switching (ZVS) of active switches has been a serious limitation of full-bridge (FBZVS) converters. Many techniques have been proposed in the past to extend the range of ZVS operation over the wider and also the full range of operation. However, in these techniques ZVS is achieved at the expense of additional conduction loss in active switches and losses in the auxiliary components. In this paper, the analysis for the additional losses in various full-range FBZVS DC-DC converters and their comparative evaluation is reported. Closed form expressions are derived for average value of device currents and losses. The loss curves for various topologies are plotted and compared. The analytical results are found to be consistent with the experimental efficiency tests performed on 500 W, 100 kHz prototype. It is concluded that a recently proposed new topology has the least penalty of additional losses.     

Synthesis of flexible polymeric shielding materials for soft gamma rays: Physicomechanical and attenuation characteristics of radiation crosslinked polydimethylsiloxane/Bi2O3 composites

Flexible lead‐free high energy radiation shielding material was developed through internal compounding. Polymer‐filler interaction, crosslinking density, specific gravity, physicomechanical characteristics, percentage attenuation, and thermal stability of the crosslinked composites were estimated. It was found that even at very high filler loading composites can be crosslinked; however, the crosslinking density was composition dependent and was highest in 10–50 wt% loading range at 100 kGy and 200 kGy. The Nielsen model was applied to understand the micromechanics of the system. Attenuation of gamma radiation from Am241 was not affected by the crosslinking density. Thermal stability of the composites was found to be significantly affected with bismuth oxide loading. POLYM. COMPOS., 37:756–762, 2016. © 2014 Society of Plastics Engineers     

Assessment of groundwater depletion–induced land subsidence and characterisation of damaging cracks on houses: a case study in Mohali-Chandigarh area,India

Bulletin of Engineering Geology and the Environment - The present study identified groundwater depletion–induced land subsidence by spaceborne differential interferometric SAR (DInSAR)...