EDXRF analysis of suspended particulate matter (SPM) from residential and industrial areas in Cairo,Egypt

Due to the remarkable increasing of the mass concentrations of suspended particulate matter (SPM) as an air pollution indicator in Greater Cairo‐Egypt, regular sampling during autumn 2014 and winter 2014/2015 seasons has been performed from industrial and residential areas. It was found that the average mass concentrations of the SPM collected from residential and industrial areas are equal to 531 ± 198 and 912 ± 230 μg/m³, respectively. These quantities are much higher than the maximum allowance level, especially for the industrial area. By utilizing three secondary targets, energy dispersive x‐ray fluorescence working under vacuum environment was used for elemental analysis of 19 elements namely; Na, Al, Si, S, Cl, K, Ca, Ti, V, Mn, Fe, Ni, Cu, Zn, Pb, Se, Br, Rb, and Sr. The present optimized selective excitation energy dispersive x‐ray fluorescence analysis has considerably enhanced the analytical range with respect to our previous similar studies, including low Z elements such as Na, Al, S, and Cl and attaining lower detection limits in the range of ng/m³. Remarkable high elemental concentrations were determined for most of the detected elements from the industrial area samples, strongly indicating the influence of the industrial and anthropogenic activities. The average percentages of the mass concentration of the detected inorganic elements account only for 3.2% and 10.5% of the total mass concentration collected from the residential and industrial areas, respectively, thus directly indicating that the content of organic pollutants in SPM is the dominant contribution.     

Optimization approaches of aircraft flight path reducing noise: Comparison of modeling methods

An optimization model of flight paths is designed for minimizing aircraft noise at reception points around airports. It is stated as a nonconvex and nonlinear control problem governed by ordinary differential equations using a jet noise model. The vertical plan and the space cases have been solved using two approaches, one direct and one indirect. The objective was initially to apply these two methods, then to carry out comparisons, and finally to retain the method which would be applied for the general case including engine and airframe sources. Results showed that the direct method is adapted for solving the problem and can be implemented with moderate computing times. It is sufficient to analyze the constrained flight path optimization of commercial aircraft reducing noise levels. The three-segment approach procedure has been obtained as an optimized flight path which can substantially reduce noise levels. This modified approach procedure has been examined and could benefit both airlines and communities.     

500 GHz mode-hop-free idler tuning range with a frequency-stabilized singly resonant optical parametric oscillator

A 1064 nm pumped continuous-wave, mid-IR (3-4 μm), signal-wave resonant optical parametric oscillator is frequency stabilized at the kilohertz jitter level to the transmission peak of an external high-finesse Fabry-Perot cavity. Owing to the high stability of the resonator length against acoustical perturbation, fine pump tuning of the idler wave around 3.3 μm results in an unprecedented mode-hop-free continuous scan over 500 GHz (17 cm?1).     

EDXRF,FTIR, and XRD characterization of low calcium oxalate urinary stones collected from arid area

Low calcium oxalate urinary stones from the kidney, bladder, and ureter have been collected from the arid area (Taif, Saudi Arabia). After careful washing and drying of the collected stones, the samples were converted into a contamination-free homogenous fine powder with a particles' size smaller than 50 μm. The processed urinary stone powders were studied using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), laboratory setup and synchrotron radiation X-ray diffraction (XRD), and energy-dispersive X-ray fluorescence (EDXRF). The activated function groups, quantitative phase analysis, and the semi-quantitative elemental analysis of the present urinary stones were identified. Seventeen elements were measured in most of the urinary stone samples. The significant elements are Ca, P, S, Cl, Zn, K, Fe, and Cu, whereas other elements were found alternatively in a few number of urinary stone samples. It was recognized that Ca exists with low concentration, which indicates the presence of different calcium phases even with low percentages. In 33% of the urinary stones, the phosphorus (P) was not measured, but there were high concentrations of sulfur (S) and low concentrations of Ca up to 2.15 ± 0.05%. The ATR-FTIR results indicate that the most compounds of the present urinary stones were urea and cystine combined with low ratios of calcium oxalate and calcium phosphate compounds. The quantitative phase analysis of the XRD of selected samples proves the presence of the cystine, urea, and calcium oxalate phases with different weight percent.     

A Hybrid Kinetic-Quantum Model for Stationary Electron Transport

Interface conditions between a classical transport model described by the Boltzmann equation and a quantum model described by a set of Schrödinger equations are presented in the one-dimensional stationary setting. These interface conditions, derived thanks to an asymptotic analysis of the Wigner transform, are shown to be flux-preserving and are used to build a hybrid model consisting of a quantum zone surrounded by two classical ones. The hybrid model is shown to be well posed when the potential is either prescribed or computed self-consistently, and the semiclassical limit of the problem is shown to give the right interface conditions between two kinetic regions (the electrostatic potential being fixed). This model can be used to describe far-from-equilibrium electron transport in a resonant tunneling diode.     

Étude spectrométrique d'un plasma induit par haute fréquence : Partie I: Performances analytiques

A new design of inductively coupled plasma generator operating at 40 MHz is described. Data are presented to show that the generator gives satisfactory performance when used in both atomic emission and absorption spectrometry, although the former has the advantage of simplicity of operation.     

Kinetics and Mechanism of the Isomerisation of 2,4,6-Triphenyl-4H-Thiopyran

Isomerisation of 2,4,6-triphenyl-4H-thiopyran into 2,4,6-triphenyl-2H-thiopyran has been studied kinetically and the rate of the reaction was determined in dimethylformamide. The first order rate constant could be expressed in terms of the Arrhenius parameters by the equation k_t = 2.85 × 10⁷ e^{?15820±110/RT}.     

2‐Amino­anilinium phosphite

The solid‐state structure of the title compound, alternatively called 2‐amino­anilinium hydrogen phosphonate, C₆H₉N₂⁺·H₂PO₃^?, shows the monoprotonated di­amine mol­ecule to be multiply hydrogen bonded to HPO₃H^? anions. There is no inter‐phosphite hydrogen bonding, contrary to previous solid‐state observations of the species.