An optimization planning technique for Suez Canal Network in Egypt

This paper introduces a proposed optimization technique POT for predicting the peak load demand and planning of transmission line systems. Many of traditional methods have been presented for long-term load forecasting of electrical power systems. But, the results of these methods are approximated. Therefore, the artificial neural network (ANN) technique for long-term peak load forecasting is modified and discussed as a modern technique in long-term load forecasting. The modified technique is applied on the Egyptian electrical network dependent on its historical data to predict the electrical peak load demand forecasting up to year 2017. This technique is compared with extrapolation of trend curves as a traditional method. The POT is applied also to obtain the optimal planning of transmission lines for the 220 kV of Suez Canal Network (SCN) using the ANN technique. The minimization of the transmission network costs are considered as an objective function, while the transmission lines (TL) planning constraints are satisfied. Zafarana site on the Red Sea coast is considered as an optimal site for installing big wind farm (WF) units in Egypt. So, the POT is applied to plan both the peak load and the electrical transmission of SCN with and without considering WF to develop the impact of WF units on the electrical transmission system of Egypt, considering the reliability constraints which were taken as a separate model in the previous techniques. The application on SCN shows the capability and the efficiently of the proposed techniques to obtain the predicting peak load demand and the optimal planning of transmission lines of SCN up to year 2017.     

Energy levels, oscillator strengths and transition probabilities for Si-like P II, S III, Cl IV, Ar V and K VI

Fine-structure calculations of energy levels, oscillator strengths, and transition probabilities for transitions among the terms belonging to 3s²3p², 3s3p³, 3s²3p3d, 3s²3p4s, 3s²3p4p, 3s²3p4d, 3s²3p5s and 3s²3p5p configurations of silicon-like ions P II, S III, Cl IV, Ar V and K VI have been calculated using configuration-interaction version 3 (CIV3). We compared our data with the available experimental data and other theoretical calculations. Most of our calculations of energy levels and oscillator strengths (in length form) show good agreement with both experimental and theoretical data. Lifetimes of the excited levels are also given.     

Wear and friction of Al–Al<Subscript>2</Subscript>O<Subscript>3</Subscript> composites at various sliding speeds

The present study addresses the dry wear behavior of Al₂O₃ 6061 Aluminum particulate composite under different sliding speeds and applied load using pin-on-disk tribometer at room temperature. Three grades of the submicron particle composites containing 10, 20, and 30 vol.% Al₂O₃ were tested. The results illustrate that higher load and higher concentration of Al₂O₃ particles lead to higher wear rates. For 10 and 20% Al₂O₃ concentrations, the wear rate decreases with increasing sliding speed, while it increases for 30% Al₂O₃. The surface morphologies of the worn composites indicate that at lower sliding speeds abrasion is dominant, while at higher sliding speeds delamination and adhesion increases. Results also indicate that the friction coefficient between the composite and the mating steel surface decreases with increasing sliding speed to a steady state.     

Improved Optoelectronic Properties of Rapid Thermally Annealed Dilute Nitride GaInNAs Photodetectors

We investigate the optical and electrical characteristics of GaInNAs/GaAs long-wavelength photodiodes grown under varying conditions by molecular beam epitaxy and subjected to postgrowth rapid thermal annealing (RTA) at a series of temperatures. It is found that the device performance of the nonoptimally grown GaInNAs p ⁺–i–n ⁺ structures, with nominal compositions of 10% In and 3.8% N, can be improved significantly by the RTA treatment to match that of optimally grown structures. The optimally annealed devices exhibit overall improvement in optical and electrical characteristics, including increased photoluminescence brightness, reduced density of deep-level traps, reduced series resistance resulting from the GaAs/GaInNAs heterointerface, lower dark current, and significantly lower background doping density, all of which can be attributed to the reduced structural disorder in the GaInNAs alloy.     

Self-standing crystalline TiO2 nanotubes/CNTs heterojunction membrane: synthesis and characterization

In the present study, we report for the first time synthesis of TiO(2) nanotubes/CNTs heterojunction membrane. Chemical vapor deposition (CVD) of CNTs at 650 °C in a mixture of H(2)/He atmosphere led to in situ detachment of the anodically fabricated TiO(2) nanotube layers from the Ti substrate underneath. Morphological and structural evolution of TiO(2) nanotubes after CNTs deposition were investigated by field- emission scanning electron microscopy (FESEM), glancing angle X-ray diffraction (GAXRD), and X-ray photoelectron spectroscopy (XPS) analyses.     

Interface architecture determined electrocatalytic activity of Pt on vertically oriented TiO(2) nanotubes

The surface atomic structure and chemical state of Pt is consequential in a variety of surface-intensive devices. Herein we present the direct interrelationship between the growth scheme of Pt films, the resulting atomic and electronic structure of Pt species, and the consequent activity for methanol electro-oxidation in Pt/TiO(2) nanotube hybrid electrodes. X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) measurements were performed to relate the observed electrocatalytic activity to the oxidation state and the atomic structure of the deposited Pt species. The atomic structure as well as the oxidation state of the deposited Pt was found to depend on the pretreatment of the TiO(2) nanotube surfaces with electrodeposited Cu. Pt growth through Cu replacement increases Pt dispersion, and a separation of surface Pt atoms beyond a threshold distance from the TiO(2) substrate renders them metallic, rather than cationic. The increased dispersion and the metallic character of Pt results in strongly enhanced electrocatalytic activity toward methanol oxidation. This study points to a general phenomenon whereby the growth scheme and the substrate-to-surface-Pt distance dictates the chemical state of the surface Pt atoms, and thereby, the performance of Pt-based surface-intensive devices.     

Application of prepared waterborne polyurethane extended with chitosan to impart antibacterial properties to acrylic fabrics

In this study, isophorone diisocyanate (IPDI), 2,2-bis (hydroxylmethyl)-propionic acid and polyethylene glycol (PEG) were employed to polymerize waterborne polyurethane. The polyurethane prepolymer was extended with chitosan of two different molecular weight (100,000 and 150,000), and used as finishing agent for acrylic fabrics. The antibacterial activity of the acrylic fabric treated with the polyurethane-chitosan solution was improved even after 15 washing times. Pretreatment of acrylic fabrics with hydrazine hydrate was found to improve the uptake of the polymer by the fabric. The effects of hydrazine and polyurethane treatments on some of the inherent properties of acrylic were assessed. The functional groups of polyurethane prepolymer as well as polyurethane extended with chitosan were confirmed with the analysis of the spectra of Fourier transform infrared spectroscopy (FT-IR).     

Numerical prediction of refrigerant mixtures' condensation inside enhanced surface vertical cylinders

A lumped parameter model has been developed to predict the liquid filmwise condensation of pure refrigerants, as well as refrigerant mixtures, inside vertical cylinder with enhanced surfaces. The mathematical formulation is based on mass, momentum and energy balance. Several constitutive relationships have been established to describe the various phenomena during condensation. Numerical results indicate that the model fairly predicted the liquid filmwise condensation phenomenon, under various conditions.     

Enthalpies of formation of liquid and solid (gallium + palladium) alloys

The enthalpies of formation of liquid (Ga + Pd) alloys were determined by direct reaction calorimetry in the temperature range 1322 <T/K < 1761 and the molar fraction range 0 <x _Pd < 0.87. The enthalpies are very negative with a minimum Δ_mix H _m = −70.4 ± 3.0 kJ mol_-1 atx _Pd = 0.6, independent of the temperature. Limiting partial molar enthalpies of palladium and gallium were calculated as Δh _m (Ga liquid in ∞liquid Pd) = −265 ± 10 kJ mol₋₁ and Δh _m (Pd liquid in ∞liquid Ga) = -144 ± 5 kJ mol₋₁. The integral molar enthalpy is given by Δ_mix H _m =x(1-x) (-143.73 -232.47x + 985.77x ²-4457.8.x ³ + 6161.1x ⁴ + 2577.4x ⁵), wherex = x _Pd. Moreover, values for the enthalpies of formation and fusion of PdGa, Pd₂Ga, and the solid solution (withx _Pd = 0.8571) have been proposed. These results have been discussed taking into account the equilibrium phase diagram. Formerly Ph.D. student, Université de Provence     

The limiting molar partial enthalpies of mixing of iron, cobalt, nickel, palladium and platinum in liquid gallium and indium

Gallium and indium have been used as solvents for the determination of the molar partial enthalpy of mixing Δ_mixh_m^o(TM, Ga or In) (denoting liquid transition metal (TM) in infinite liquid gallium or indium) of the pure liquid transition metals Fe, Co, Ni, Pd and Pt by direct reaction calorimetry between 1000 K and 1500 K with the exception of Δ_mixh_m^o(Fe, In) (because of the shape of its equilibrium phase diagram). All the limiting enthalpies listed below refer to the liquid state. With pure gallium as solvent, they correspond to the reaction

TM(liq) − nGa(liq) → TM₁Ga_n(liq)

at the experimental temperature T_e, with n 1.

1. (i) Δ_mixh_m^o in gallium is found for Fe, Co, Ni, Pd and Pt to be −2, −44, −82, −144 and −155 kJ mol⁻¹.

2. (ii) Δ_mixh_m^o in indium is found for Co, Ni, Pd and Pt to be +28, −25, −127 and −114 kJ mol⁻¹.

In both solvents, these limiting enthalpies vary with a similar trend. This observation makes it possible to predict the limiting molar partial enthalpy Δ_mixh_m^o(Fe, In) of mixing of iron in indium as +70 kJ mol⁻¹. The results have been compared with the data proposed by Miedema and co-workers.