Exact solutions of Kolmogorov-Petrovskii-Piskunov equation using the modified simple equation method

The modified simple equation method is employed to find the exact solutions of the nonlinear Kolmogorov-Petrovskii-Piskunov （KPP） equation. When certain parameters of the equations are chosen to be special values, the solitary wave solutions are derived from the exact solutions. It is shown that the modified simple equation method provides an effective and powerful mathematical tool for solving nonlinear evolution equations in mathematical physics.     

Construction and performance characterization of ion-selective electrodes for potentiometric determination of pseudoephedrine hydrochloride applying batch and flow injection analysis techniques

New pseudoephedrine selective electrodes have been constructed of the conventional polymer membrane type by incorporation of pseudoephedrine-phosphotungstate (PE-PT) or pseudoephedrine-silicotungstate (PE-SiT) ion-associates in a poly vinyl chloride (PVC) membrane plasticized with dibutyl phthalate (DBP). The electrodes were fully characterized in terms of the membrane composition, temperature, and pH. The electrodes exhibited mean slopes of calibration graphs of 57.09 and 56.10 mV concentration decade(-1) of PECl at 25 degrees C for (PE-PT) and (PE-SiT) electrodes, respectively. The electrodes showed fast, stable, and near-Nernstian response over the concentration ranges 6.31 x 10(-6)-1.00 x 10(-2) and 5.00 x 10(-5)-1.00x10(-2) M in the case of PE-PT applying batch and flow injection (FI) analysis, respectively, and 1.00 x 10(-5)-1.00 x 10(-2) and 5.00 x 10(-5)-1.00x10(-2) M in the case of PE-SiT for batch and FI analysis system, respectively. Detection limit was 5.01x 10(-6) M for PE-PT electrode and 6.31x10(-6) M for PE-SiT electrode. The electrodes were successfully applied for the potentiometric determination of pseudoephedrine hydrochloride (PECl) in pharmaceutical preparations with mean recovery 101.13 +/- 0.85% and 100.77+0.79% in case of PE-PT applying batch and flow injection systems, respectively, and 100.75+0.85% and 100.79 +/- 0.77% in case of PE-SiT for batch and flow injection systems, respectively. The electrodes exhibited good selectivity for PECl with respect to a large number of inorganic cations, sugars and amino acids.     

Simultaneous determination of mebeverine hydrochloride and sulpiride using the first derivatives of ratio spectra and chemometric methods.

Two methods are described for the simultaneous determination of mebeverine hydrochloride (MB) and sulpiride (SU) in their combinations. The first method depends on the first derivative of the ratio spectra by measurement of the amplitudes at 263.7 and 234.9 nm for MB and SU, respectively. The linear ranges and detection limits are 4.0-40.0 and 0.72 microg/ml for MB and 1.0-10.0 and 0.34 microg/ml for SU. In the second case, a chemometric (classical least squares) method was developed. The concentration data matrices were obtained by using different concentrations of pure drugs in 0.1 M HCl. The absorbance data matrix corresponding to each concentration data matrix was obtained by the measurements of absorbances in the range 200-300 nm in their zero order spectra; then calibration was obtained by using the absorbance data matrix and the concentration data matrix for the prediction of the unknown concentrations of MB and SU in their mixture. The numerical values were calculated by using Matlab R12 version 6.0 and Origin 5.0 software. The procedures do not require any separation steps. These two methods were successfully applied for assaying the pharmaceutical formulation, of Colona tablets.     

New plastic membrane and carbon paste ion selective electrodes for the determination of triprolidine.

Triprolidine (Trip) ion selective electrodes of three types: the conventional polymer membrane (I), graphite coated electrode (II) and carbon paste electrode (III), have been prepared, based on the ion pair of triprolidine hydrochloride with sodium tetraphenylborate. The electrodes exhibit a linear response with a mean calibration graph slope of 56.12, 55.00 and 54.32 mV decade(-1) at 25 degrees C for I, II and III, respectively, within the concentration ranges 1.96 x 10(-5) - 1.00 x 10(-2) M for I and 3.84 x 10(-5) - 1.00 x 10(-2) M for II and III. The detection limits are 1.13+/-0.13 x 10(-5), 1.70+/-0.06 x 10(-5) and 1.78+/-0.05 x 10(-5) M for the three electrodes, respectively. The change of pH within the ranges 4.85 - 8.75 and 4.70 - 8.50 for I and III, respectively, did not affect the electrode performance. The standard electrode potentials were determined at different temperatures and were used to calculate the isothermal coefficient of the electrode. The electrodes showed a very good selectivity for Trip with respect to a large number of inorganic cations and compounds. The standard addition method was applied to the determination of TripCl in pure solution, pharmaceutical preparations, and urine samples.     

Study of stress-strain characteristics of SBR and blended NR/SBR rubber

The effect of temperature and carbon black (CB) on the mechanical characteristics of styrene-butadine rubber (SBR) and natural rubber (NR) was studied at various temperatures. The relation obtained between true stress and true strain for both types of rubber showed three regions at room temperature and two regions at high temperature. The optimum CB concentration was found to be 95 phr for the unblended samples as it increases the stiffness of the SBR rubber materials at a maximum value. It was also found that the addition of NR to SBR increases the elasticity in the plastic region. The activation energy at the fracture of SBR samples decreased from about 2.7×10^–20 to 1.8×10^–20 J while for the blended samples NR/SBR it increased from 8×10^–20 to 10.1×10^–20 J with increasing CB concentration.     

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Flow injection potentiometric determination of pancuronium bromide in pharmaceutical preparation and urine samples using modified carbon paste electrodes

Carbon paste electrodes for pancuronium bromide was prepared based on ion association complexes of pancuronium bromide with sodium tetraphenylborate (NaTPB) or ammonium reineckate using dibutyl phthalate as solvent mediator and tetradodecylammonium tetrakis-(4-chlorophenyl)borate (ETH 500) as lipophilic additive. The sensors showed a near-Nernstian slope of 28.1 mV concentration decade(-1) at 25°C within the concentration range 6.31×10(-6)-1.00×10(-2) M in case of pancuronium-tetraphenylborate electrode and 26.6 mV concentration decade(-1) in the concentration range 5.66×10(-5)-1.00×10(-2) M in case of pancuronium-reineckate electrode. The sensors were successfully applied for the potentiometric determination of pancuronium bromide in pharmaceutical preparation and biological fluids in batch and flow injection conditions.     

A note on the modified simple equation method applied to Sharma-Tasso-Olver equation

Jawad et al. have applied the modified simple equation method to find the exact solutions of the nonlinear Fitzhugh-Naguma equation and the nonlinear Sharma-Tasso-Olver equation. The analysis of the Sharma-Tasso-Olver equation obtained by Jawad et al. is based on variant of the modified simple equation method. In this paper, we provide its direct application and obtain new 1- soliton solutions.     

A modified extended method to find a series of exact solutions for a system of complex coupled KdV equations

In this paper an algebraic method is devised to uniformly construct a series of complete new exact solutions for general nonlinear equations. For illustration, we apply the modified proposed method to revisit a complex coupled KdV system and successfully construct a series of new exact solutions including the soliton solutions and elliptic doubly periodic solutions.