M. M. Azab

Organotin polymers—XVI. Synthesis of p-acryloyloxybenzoic acid and n-methacryloyloxytetrabromophthalimide and copolymerizations with tri-n-butyltin acrylate and methacrylate

Abstract p -Acryloyloxybenzoic acid (ABA) and N -methacryloyloxytetrabromophthalimide (NMTP) were prepared. The monomer reactivity ratios for the copolymerization of tri-n-butyltin acrylate (monomer-1) with ABA and NMTP have been found to be r 1 , = 1.01, r 2 = 0.40 and r 1 , = 0.69, r 2 = 0.90 respectively; those for tri-n-butyltin methacrylate (monomer-l) with ABA and NMTP were r 1 = 2.21, r 2 = 0.87 and r 1 = 0.85, r 2 = 1.35 respectively. Copolymerizations were carried out in solution at 70° using 1 mol% azobisisobutyronitrile as initiator. The structures of the monomers were investigated by i.r. and 1 H-NMR.

Identification of one-diode model parameters of PV devices from nameplate information using particle swarm and least square methods

The paper proposes a simple method to estimate the parameters of a one-diode model of PV modules based on particle swarm optimization (PSO) and least square (LS) algorithms. The employed method requires only the PV module nameplate ratings at three points on the I-V curve at Standard Test Conditions: short circuit current, open circuit voltage and maximum power (VMPP, IMPP). The method is verified on two different types of PV modules (poly-crystalline and monocrystalline). A comparison between actual experimental data curves (obtained from manufacturer data sheets) and the predicted PV characteristics is carried out for different operating conditions. The PSO algorithm has been tested 100 times to determine the average value of the model parameters. The corresponding relative percentage error between measured and predicted PV electrical parameters did not exceed 8 % in the worst case, while the elapsed CPU time of the PSO algorithm was less than 7 sec. The results proved the validity and effectiveness of the method to identify with good accuracy the parameters of a PV module using only the limited datasheet information. It has been observed that the LS method can fail to find a solution without a proper selection of the initial values. The limitation of the LS method has been overcome by utilizing the final PSO solution as initial condition for the LS nonlinear curve fitting algorithm. With the LS search method (initialized by PSO results) accurate solution is also obtained. So, the proposed parameter estimation approach has been validated by two techniques PSO and LS. The main contribution of this approach is its suitability for rapid prototyping of PV systems with a high precision without the need to install an experimental test rig.

Transformer Parameters Estimation From Nameplate Data Using Evolutionary Programming Techniques

This paper proposes a simple and effective evolutionary computation-based technique to estimate the equivalent circuit parameters of a single-phase transformer from its nameplate data without the need to conduct any experimental measurements. Two techniques, namely: particle swarm optimization and genetic algorithm are employed to track nameplate data by minimizing certain objective functions. The effectiveness of the proposed technique is examined through its application for three single-phase transformers of different ratings. The results show that evolutionary computation techniques can precisely identify transformer equivalent circuit parameters. The proposed technique can be extended to estimate the parameters of a three-phase power transformer from its nameplate data without taking the transformer out of service to carry out any experimental testing.

Efficacy and safety of tamsulosin oral-controlled absorption system, solifenacin, and combined therapy for the management of ureteric stent-related symptoms.

Abstract Objectives: To evaluate the efficacy of solifenacin, tamsulosin oral-controlled absorption system (OCAS), and the combination of both drugs on JJ stent-related symptoms using the validated Arabic version of the ureteric stent symptom questionnaire (USSQ). Patients and methods: In all, 260 patients who had undergone JJ stenting of the ureter for different endoscopic urological procedures were postoperatively randomly assigned into four equal groups. Patients in Group I received no treatment and served as the control group, Group II patients received tamsulosin OCAS 0.4 mg daily, Group III patients received solifenacin 5 mg daily, and Group IV patients received a combination of both drugs. Before stent removal, all patients completed the Arabic version of the USSQ. Results: In all, 234 patients completed the study, comprised of 56 in Group I, 59 in Group II, 58 in Group III, and 61 in Group IV. Baseline characteristics and indications for JJ stenting were comparable in the four groups. There were highly significant differences in all items of the USSQ between the treatment groups and the controls, while Group II and III were comparable. The USSQ score was significantly lower in Group IV vs Groups II and III. Crossing of the distal curl of the stent to the midline had a significant positive correlation with the severity of the urinary symptoms, body pain, general health, and work performance in the medicated groups. Conclusions: Combined therapy with tamsulosin OCAS 0.4 mg daily and solifenacin 5 mg daily is a safe and well-tolerated management for stent-related symptoms. However, stent position remains a significant factor affecting response to medical therapy and patients’ health-related quality of life.

Organotin polymers—XIX. Copolymerization parameters of p-acryloyloxy-tri-N-butyltin benzoate with allyl methacrylate, N-vinylpyrrolidone and vinyl acetate

Abstract Radical copolymerizations of p -acryloyloxy-tri-n-butyltin benzoate (ABTB) with allyl methacrylate, N -vinyl pyrrolidone and vinyl acetate were carried out in solution at 70° using 1 mol% azobisisobutyronitrile as initiator. The copolymer compositions were determined from tin analyses. The monomer reactivity ratios for copolymerizations of ABTB (monomer-1) with allyl methacrylate, N -vinyl pyrrolidone and vinyl acetate have been found to be r 1 = 0.28, r 2 = 0.89; r 1 = 0.07; r 2 = 0.40 and r 1 = 0.92, r 2 = 0.99, respectively. The Q and e values for the organotin monomer were calculated.

Synthesis and surface activity of self‐sequestering surfactants

A novel two series of self‐sequestering surfactants have been prepared by the reaction of itaconic acid, phthalic anhydride, citric acid with oxypropylated 1,4‐butane diol and oxypropylated 1,6‐hexane diol. The structure features of these surfactants have been confirmed by IR and 1H NMR spectra. These surfactants exhibit excellent properties of self‐sequestering. Besides good surface active properties including surface tension, interfacial tension, low foaming, good wetting properties, good stability towards acidic and basic media, emulsifying power and dispresent properties, solubilization properties and good biodegradability, they possess autonomous sequestering ability without any help of additional sequestering agent.

Electropolymerization of N-methacryloyloxy phthalimide monomer using sacrificial nickel anode and characterization of the resulting polymer

Abstract The electropolymerization of N-methylacryloyloxy phthalimide has been studied in DMF using a sacrificial nickel anode in the presence of tetrabutylammonium perchlorate as supporting electrolyte. The effect of different reaction parameters such as the type of electrolyte, concentration of monomer and electrolyte, current strength, the duration of electrolysis and the temperature of the reaction on the yield of the polymer and the rate of polymerization were studied. It was found that the nickel content in the obtained polymer depends on the concentration of the monomer. A mechanism of electropolymerization is suggested and confirmed by i.r., 1 H-NMR, thermal analysis and electrical conductivity measurements.

Preparation of new organotin polymers via exchange reactions

Purpose – Preparation of new organotin polymers via a new synthetic route based on the exchange reactions of pentachlorophenyl acrylate or methacrylate with amino‐tri‐phenyltin benzoates or hydroxyl‐tri‐phenyltin benzoates.Design/methodology/approach – The pentachlorophenyl acrylate or methacrylate was prepared by polymerisation in solution with azobisisobutyrontrile as a free radical initiator. The polymers obtained were allowed to undergo exchange reactions with amino‐tri‐phenyltin benzoates or hydroxyl‐tri‐phenyltin benzoates. The structure of the polymers prepared was confirmed by IR spectroscopy. Films were prepared from purified organotin polymers solution on glass, PVC and tin plates. The release of tin compound from the films, when immersed in aqueous media, was assessed. The concentration of the released tin (ppm) was measured by atomic adsorption spectrophotometer.Findings – The new synthetic route was effective, the organotin polymers prepared had good film properties and the release of tin com...

A novel evolutionary technique to estimate induction machine parameters from name plate data

Owing to the fact that the performance and control design of large scale induction machines depend on accurate knowledge of its equivalent electrical circuit parameters, precise identification of these parameters is essential. Current methods used to quantify induction machine parameters call for performing several experimental testing such as no-load, locked-rotor and DC tests which may not be available due to the lack of hardware, experience and time required to perform the tests. In this paper, two different evolutionary computational techniques namely; bacterial foraging and genetic algorithm, are employed to estimate these parameters from machine nameplate data without conducting any experimental measurements. The accuracy of the proposed techniques is assessed through their application on squirrel cage and wound rotor induction motors of different ratings. The motors performance computed using the proposed techniques is compared with that computed using classical practical measurements. The obtained results reveal the ability of evolutionary techniques to estimate the equivalent electrical circuit parameters of induction machines with a reasonable degree of accuracy. Results also show that bacterial foraging approach is more accurate than genetic algorithm in estimating induction machine parameters.

Terpolymerizations of p-acryloyloxy-tri-n-butyltin benzoate with alkyl acrylates or vinyl acetate and N-vinyl-2-pyrrolidone

Abstract Ternary copolymerization reactions of p-acryloyloxy-tri-n-butyltin benzoate (ABTB) with N-vinyl-2-pyrrolidone (NVP) and alkyl acrylates [ethyl (EA) and butyl acrylate (BA)] or vinyl acetate (VA) were carried out in solution at 65° in the presence of a free radical initiator. Experimental terpolymerization data agreed well with calculations based on the Alfrey-Goldfinger equation. The unitary, binary and ternary azeotropes of various systems studied was easily determined by a computer program. The results obtained showed that there is no ternary azeotropic compositions for any terpolymer system studied. Selective unitary and binary azeotropic compositions were polymerized and the results obtained showed good agreement between the theoretical and experimental terpolymer composition for each case.