Ab initio Insight of the Electronic,Structural, Mechanical and Optical Properties of X $$_3$$ 3 P $$_2$$ 2 (X= Mg,Ca) from GGA and Hybrid Functional (HSE06)

Journal of Superconductivity and Novel Magnetism - In this paper, the structural, mechanical and optoelectronic properties of X $$_3$$ P $$_2$$ (X= Mg, Ca) have been investigated by using the...     

Multi-Criteria Process-Based Calibration Using Functional Data Analysis to Improve Hydrological Model Realism

It has been argued that rainfall-runoff model calibration based solely on streamflow is not sufficient to evaluate the realism of a hydrological model to represent the internal fluxes. Therefore, model calibration has evolved to evaluating model performance using a number of hydrological signatures that link the model to the underlying processes. However, this approach uses goodness-of-fit measures, unable to describe the entire dynamic of time series, to evaluate model consistency and to simulate hydrological signatures. The present paper develops a stepwise multicriteria calibration using hydrograph partitioning and calibration criteria defined on the basis of Functional Data Analysis (FDA), a statistical tool that conserves all important features of the hydrograph by approximating times series as a single function. The aim of this approach is to improve model realism by scrutinizing model components and by evaluating its ability to reproduce the entire flow dynamic. The proposed approach is compared to a calibration against daily streamflow only. The stepwise calibration improved the estimation of the flood curve, the annual peak volume as well as the performance of the model at sites other than the calibration station.     

Optimal locations and tuning of robust power system stabilizer using genetic algorithms

Optimal locations and design of robust multimachine power system stabilizers (PSSs) using genetic algorithms (GA) is presented in this paper. The PSS parameters and locations are computed to assure maximum damping performance under different operating conditions. The efficacy of this technique in damping local and inter-area modes of oscillations in multimachine power systems is confirmed through nonlinear simulation results and eigenvalues analysis.     

Enhanced decision making in multi-scenarios for autonomous vehicles using alternative bidirectional Q network

Neural Computing and Applications - To further enhance decision making in autonomous vehicles field, grant more safety, comfort, reduce traffic, and accidents, learning approaches were adopted,...     

Evaluation of hydrogen concentration effect on the natural gas properties and flow performance

The natural gas flowing through transmission pipeline is impure and has a wide range of non-hydrocarbons components at different concentrations like hydrogen. The presence of hydrogen in the natural gas mixture influences its properties and flow performance. The effect of hydrogen concentration on the natural gas flowing through a transportation pipeline has not been adequately investigated and widely comprehended. In this paper, several mixtures flow through pipeline include typical natural gas and hydrogen at different concentrations up to 10% are evaluated to demonstrate their impact on the flow assurance and the natural gas properties. The string Ruswil – Griespass part from the Transitgas project with 94 km length is simulated applying Aspen Hysys Version 9 and validated using Aspen Plus. The simulation specifications were 1.228 1 10⁶ kg/h mass flowrate, 1200 mm and 1164 mm the outer and inner diameters, and 75 bar and 29.4 °C operating pressure, and temperature. The effect of different hydrogen concentrations has been examined and the differences from the typical mixture are estimated. The results show that the presence of hydrogen in the natural gas mixture reduces its density, 10% hydrogen content records 11.78% reduction in the density of typical natural gas. Interestingly, it has been found that up to 2% of hydrogen concentration turns in elevating the viscosity of the typical natural gas while the viscosity decreases at the point that hydrogen content increases above 2%. In addition, the pressure losses over the transmission pipeline increases due to the presence of hydrogen, 10% hydrogen concentration turns in 5.39% increase in the pressure drop of the natural gas mixture. Also, the temperature drop across the pipeline decreases as the hydrogen concentration increases; 10% hydrogen content can result in a 6.14% reduction in the temperature drop across the pipeline. As well as, the findings prove that the hydrogen strongly impacts the phase envelope by changing from size symmetric to size asymmetric diagram. The effect of pipeline elevations has been investigated by changing the elevation up to 25 m uphill and 25 m downhill. The results state that increase the pipeline elevation turns in increasing the pressure losses over the pipeline length. Along with this, the results illustrate that the presence of hydrogen in the mixture elevates the critical pressure and reduces the critical temperature.     

Nash-Cournot equilibrium of a deregulated electricity market using competitive coevolutionary algorithms

In this paper, a competitive coevolutionary approach is used to find out the Nash-Cournot equilibrium of an oligopolistic electricity market based on either centralized or bilateral structure, where the transmission constraints are considered. We consider a market game played by bounded evolutionary agents, adapting their strategies to maximize their profits in a competitive environment. Under the effect of the competition, the coevolved agents are led toward an equilibrium point where each agent population is invaded by an Evolutionary stable Strategy.     

Bibliometric analysis of diabetes mellitus research output from Middle Eastern Arab countries during the period (1996–2012)

The main objective of this study was to analyze research productivity originating from Middle East Arab (MEA) countries in the field of diabetes mellitus (DM). Data from January 1, 1996 till December 31, 2012 were searched for documents with specific words in diabetes as a “source title” and a list of 13 MEA countries as affiliation country. Research productivity was evaluated based on number of publications, citation analysis, indexing in Institute for Scientific Information and impact factor (IF). The 13 MEA countries published a total of 479 documents in 41 diabetes journals. This number represents 0.75 % of the total documents produced globally in the field of DM. The number of published documents increased by around fivefold from early 2000 to 2012. Of the 41 journal titles retrieved, 24 (58.5 %) had their IF listed in the journal citation reports 2012. Forty-two documents (14.5 %) were published in journals that had no official IF. The total number of citations for documents published from MEA countries in the field of DM, at the time of data analysis, was 5,565 with an h index of 35. The median (inter-quartile range) citation for documents from the 13 MEA countries was 4 (1–11). The top productive institution in the field of DM was United Arab Emirates University with 51 documents (10.6 %). Authors from MEA countries collaborated mostly with authors in countries like United Kingdom, USA, and Germany. The present data show promising and relatively good diabetes research productivity in MEA countries especially after 2008.     

Dielectric and Photo-Dielectric Properties of TlGaSeS Crystals

The room temperature, dark and photo-dielectric properties of the novel crystals TlGaSeS are investigated in the frequency, intensity and biasing voltage having ranges of ~ 1–120 MHz, 14–40 klux and 0–1 V, respectively. The crystals are observed to exhibit a dark high frequency effective dielectric constant value of ~ 10·65 × 10³ with a quality factor of ~ 8·84 × 10⁴ at ~ 120 MHz. The dielectric spectra showed sharp resonance– antiresonance peaks in the frequency range of ~ 25–250 kHz. When photoexcited, pronounced increase in the dielectric constant and in the quality factor values with increasing illumination intensity are observed. Signal amplification up to ~ 33% with improved signal quality up to ~ 29% is attainable via photoexcitation. On the other hand, the illuminated capacitance–voltage characteristics of the crystals reflected a downward shift in the voltage biasing and in the built-in voltage of the device that is associated with increase in the uncompensated carrier density. The increase in the dielectric constant with increasing illumination intensity is ascribed to the decrease in the crystal's resistance as a result of increased free carrier density. The light sensitivity of the crystals, the improved dielectric properties and the lower biasing voltage obtained via photoexcitation and the well-enhanced signal quality factor of the crystals make them promising candidates for optical communication systems.