Thermal transfer simulation regarding the rotational moulding of polyamide 11

Simulation of thermal phenomena in rotational moulding is very important to follow the evolution of the temperature in various zones of this process. It was a question of modelling heat gradients developing in rotational moulding part. Thermal model tested take into account the temperature change (thermal transfer mechanism) of melting and crystallization pseudo-stages (enthalpy method). Series of tests in polyamide 11 (PA11) were carried out by means of rotational moulding STP LAB, and non-isothermal crystallization kinetics of rotational moulding PA11 grade are measured and analysed by DSC technique type TAQ20. A result of non-isothermal crystallization of the studied polyamide was confronted with Ozawa model. In order to test the validity degree of enthalpy method (layer to layer), another approach based on Ozawa model has also been used in the case of cooling pseudo-stage. As results, the rotational moulding of PA11 was successfully carried out. The simulation of the fusion and crystallization stages, by application of Ozawa model coupled with enthalpy method gave a good representation of experimental data.     

A fast and green reversed‐phase HPLC method with fluorescence detection for simultaneous determination of amlodipine and celecoxib in their newly approved fixed‐dose combination tablets

A fast, green, sensitive, and accurate analytical method using high‐performance liquid chromatography couple with fluorescence detection was established and validated for the simultaneous determination of amlodipine besylate and celecoxib in their recently approved fixed‐dose combination tablets (1:20). Separation of the two drugs was achieved on C₁₈ reversed‐phase column (Thermo ODS Hypersil, 4.6 × 250 mm, particle size 5 µm) using acetonitrile:potassium phosphate buffer (50 mM; pH 5.5, 60:40 v/v) as a mobile phase at 40°C, which eluted at a rate of 1 mL/min. Detection was carried out with excitation and emission wavelengths of 360 and 446 nm for amlodipine and 265 and 359 nm for celecoxib, respectively. The method was linear over a concentration range of 0.05‐2 and 0.05‐10 µg/mL and limit of detection reached to 0.017 and 0.0167 µg/mL for amlodipine and celecoxib, respectively. The developed method was successfully applied to assess the cited drugs in their newly FDA approved fixed‐dose combination tablet dosage form. Furthermore, the method was found to be sensitive and eco‐friendly green alternative to the reported methods as it was evaluated according to the green analytical procedure index tool guidelines and analytical Eco‐Scale.     

Qualitative properties of solutions to a nonlocal evolution system

In this paper, we investigate the local existence and the finite‐time blow‐up of solutions for a semi‐linear parabolic system with a nonlinear memory. Moreover, we give the blow‐up rate of solutions and the necessary conditions for local or global existence. Copyright © 2011 John Wiley & Sons, Ltd.     

Boundary-value problems for differential equations of fractional order

We consider boundary-value problems for differential fractional-order equations. In particular, some areas in the complex plane, where the problems under consideration have no eigenvalues, are separated.     

Performance and comparison of fiber vibration sensing using SAC-OCDMA with direct decoding techniques

Intensity modulated fiber vibrations sensing using Khazani Syed (KS) and Modified Quadratic Congruence Code (MQC) code for quasi distributed vibration measurement have been evaluated. The systems employed Spectral Direct (SD) Decoding for Spectral Amplitude Coding-Optical Code Division Multiple Access (SAC-OCDMA). SAC-OCDMA is adopted because of its enormous impact in dealing with Multiple Access Interference (MAI). The setup was carried out for three sensor points in three consecutive measurements. The performance of the sensing system with the KS and MQC codes were compared at the same weight and number of code sequence. It was observed that the applied vibration frequencies were obtained at the receivers and the signal employing MQC are received at slightly better power than KS code. However, KS code setup employed less number of components and therefore, reduce the cost and complexity of achieving quasi-distributed vibration sensing.     

Preparation of Al-magadiite material,copper ions exchange and effect of counter-ions: antibacterial and antifungal applications

Research on Chemical Intermediates - In this work, the Al-magadiite is synthesized by the hydrothermal method. It is then used to prepare three copper exchanged materials using copper nitrate,...     

Realization of a low threshold multiwavelength brillouin/erbium fiber laser by optimizing the reflected power

A multiwavelength Brillouin/erbium fiber laser (BEFL) with low threshold power is realized. A low threshold power of 3 mW and a wide tuning range of 18 nm can be achieved by controlling the reflected power in the nonlinear optical loop mirror (NOLM). Up to 24 lines with a wavelength spacing of 0.086 nm are generated at the Brillouin pump and at the 1 480-nm pump with 0.5 dBm (0.9 mW) and 25 mW of power, respectively.     

On near-optimal necessary and sufficient conditions for forward-backward stochastic systems with jumps,with applications to finance

We establish necessary and sufficient conditions of near-optimality for nonlinear systems governed by forward-backward stochastic differential equations with controlled jump processes (FBSDEJs in short). The set of controls under consideration is necessarily convex. The proof of our result is based on Ekeland’s variational principle and continuity in some sense of the state and adjoint processes with respect to the control variable. We prove that under an additional hypothesis, the near-maximum condition on the Hamiltonian function is a sufficient condition for near-optimality. At the end, as an application to finance, mean-variance portfolio selection mixed with a recursive utility optimization problem is given. Mokhtar Hafay