Journal of the Association of Arab Universities for Basic and Applied Sciences最新文献

Nitrofurantoin (NIT) is used as an antibiotic for the treatment of urinary tract infection. To determine the concentration of NIT in pharmaceutical preparations, two cost-effective extraction-free flow injection (FI) spectrophotometric methods (direct and indirect) were studied. The direct FI method was based on the reaction of NIT with potassium hydroxide and the formation of a red/orange coloured product with absorbance measured at 471 nm. The indirect method used a reduction reaction of NIT and involved an oxidative coupling step with 3-methyl-2-benzothiazolinone hydrazone hydrochloride (MBTH). The second method resulted in a green coloured product with absorbance measured at 610 nm. Both direct and indirect FI methods were in agreement with Beer’s law over a concentration range of 5–300 µg/mL. In addition, the limit for detection of the reaction product for direct and indirect method was 1.9 and 4.8 µg/mL, respectively. FI spectrophotometric methods used in the present study can be applied for the analysis of NIT in different pharmaceutical dosage forms.

In this paper, a study of simultaneous adsorption of mixture dyes of Basic Blue 41 and Basic Yellow 28 in binary system was done using two types of activated carbon and compared with a single dye system in a batch mode. A competitive adsorption between the two cationic dyes was observed and it was noticed that Basic Blue 41 was favored. Kinetics of each dye in single and binary systems was found to follow pseudo-second-order rate kinetic model, with a good correlation (higher than 0.99). The single component equilibrium data were analyzed using the Langmuir and Freundlich isotherms. Overall, the Langmuir isotherm showed a better fitting for all adsorptions under investigation in terms of correlation coefficient. As the binary adsorption is competitive, extended Langmuir models could not predict the binary component isotherm well. The essential parameters which affect the removal efficiency of binary mixture solution such as pH, temperature and adsorbent type were optimized using full factorial design methodology. Effect of parameters and interaction were analyzed using Pareto chart, main effect and interaction effect. In various industrial effluents like textile industries and plant-produced water, dyes are existent in mixture form. So, this work might be of great benefit in knowing to remove the used dyes.

The magnetohydrodynamic (MHD) flow of a generalized Maxwell fluid induced by a moving plate has been investigated, where the second-order slip between the wall and the fluid in the wall is considered. The fractional calculus approach is used to establish the constitutive relationship model of the non-Newtonian fluid model. Exact analytical solutions for the velocity field and shear stress in terms of Fox H-function are obtained by means of the Laplace transform. The solutions for the generalized Maxwell second-order slip model without magnetic field, the MHD flow of generalized Maxwell flow without slip effects or first-order slip model can be derived as the special cases. Furthermore, the influence of the order of fractional derivative, the magnetic body force, the slip coefficients and power index on the velocity and shear stress are analyzed and discussed in detail. The results show that the velocity corresponding to flows with slip condition is lower than that for flow with non-slip conditions, and the velocity with second-slip condition is lower than that with first-order slip condition.

Cellulose was isolated from Luffa cylindrica sponge (LC) and modified by introducing acetyl ether functionality to its surface via simple reaction mechanism. L. cylindrica cellulose (LCC) and the acetyl ether modified L. cylindrica cellulose (LCS) were characterized using Fourier transformed infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), particle size distribution, zeta potential, thermogravimetric analysis (TGA) and Brunauer–Emmett–Teller surface area analysis (BET). They were further evaluated for water holding capacity, oil holding capacity, swelling capacity and heavy metal adsorption capacity. LC gave a cellulose yield of 46%. The XRD result revealed LCC and LCS to be typical of cellulose I crystal with LCS exhibiting higher crystallinity than LCC. Hydrophilicity was reduced in LCS with LCC showing higher water holding capacity, oil holding capacity, swelling capacity and heavy metal adsorption capacity. This study showed that surface modification of cellulose with acetyl ether group has the capacity of reducing hydrophilicity in cellulose.

In this paper, the linear and nonlinear Fokker-Planck equations (FPE) are solved by a semi-analytical iterative technique. This technique was proposed by Temimi and Ansari (TAM) in 2011. It is used to obtain the exact solutions for the 1D, 2D and 3D FPE. We solve several linear and nonlinear examples to show that the method is efficient and applicable. The results demonstrate that the presented method is very effective and reliable and does not require any restrictive assumptions for nonlinear terms. A symbolic manipulator Mathematica®10 was used to evaluate terms in the iterative process.

Three Gemini quaternary ammonium surfactants based on polyethylene glycol have been prepared and characterized using FTIR and ¹HNMR spectra. The effect of ethylene oxide units’ number on the steel corrosion in 1.0 M HCl has been estimated using weight loss, polarization and electrochemical impedance spectroscopy. The Gravimetric technique has been done at three different temperatures 25, 40 and 55 °C. The synthesized Gemini cationic surfactants with the higher molecular weight (higher number of ethylene oxide units) showed the higher inhibition efficiency under all conditions. All the prepared Gemini inhibitors showed higher inhibition efficiency upon raising the solution temperature from 25 to 55 °C. The synthesized inhibitor G1500Br showed inhibition efficiency reach to 94% at temperature 55 °C. The Langmuir adsorption isotherm is the best-fitted isotherm concerning the tested Gemini surfactants adsorption onto steel surface. The change in the free energy of adsorption refers to physicochemical adsorption on steel surface. The synthesized materials act as a mixed-type inhibitor based on the potentiodynamic polarization results.

In this paper, a fourth order integro-differential arising in the modeling of suspension bridge. A hybrid Genetic Algorithm (GA) and Nelder-Mead (NM) optimization technique is employed along with collocation finite element method and Optimal Homotopic Asymptotic Method. The solutions are compared with existing solutions. A excellent comparison is obtain results are shown, graphs and tables are shown.

The objective of this study is to clarify, for the first time in Morocco, the impact of culture on seed yield, growth parameters, yield and antioxidant activity of seed essential oils obtained from wild and cultivated fennel. The cultivation test was installed according to the principles of organic agriculture in a parcel at the oasis of Oukhite South East of Morocco under a completely randomized design with three replications. The agro-morphological characteristics were evaluated during two successive years (2014 and 2015). The results showed that fennel produces more of seed and total dry matter under culture conditions and both are more important in second year. The best performance of seed yield and total dry matter are 20.53 qx/ha and 199.79 qx/ha respectively. Domestication has not improved the yield and the antioxidant activities of fennel seed essential oils. In fact, wild fennel presented an essential oil yield significantly high (3.67%) compared to cultivated fennel (2.13%). For both applied tests DPPH and reducing power, essential oil obtained from wild plant presented the most important antioxidant power (IC₅₀:10.62 ± 0.33 and 29.49 ± 0.52 mg/mL) compared to that extracted from cultivated plant (IC₅₀:13.08 ± 0.34 and 32.30 ± 0.02 mg/mL). However, fennel cultivation is promising. It will permit to achieve interesting seed yields and may be good alternative to safeguard this species as well as to be used as an antioxidant natural source.

In this paper, micropolar fluid flow and heat transfer in a permeable channel have been investigated. The main aim of this study is based on solving the nonlinear differential equation of heat and mass transfer of the mentioned problem by utilizing a new and innovative method in semi-analytical field which is called Akbari–Ganji’s Method (AGM). Results have been compared with numerical method (Runge–Kutte 4th) in order to achieve conclusions based on not only accuracy and efficiency of the solutions but also simplicity of the taken procedures which would have remarkable effects on the time devoted for solving processes.

Results are presented for different values of parameters such as: Reynolds number, micro rotation/angular velocity and Peclet number in which the effects of these parameters are discussed on the flow, heat transfer and concentration characteristics. Also relation between Reynolds and Peclet numbers with Nusselts and Sherwood numbers would found for both suction and injection

Furthermore, due to the accuracy and convergence of obtained solutions, it will be demonstrating that AGM could be applied through other nonlinear problems even with high nonlinearity.

In nano-medicine, attempts of using the carbon-nanotubes (CNTs) as drug-carriers are undertaken especially in the treatment of cancer. These (CNTs) are first injected into the blood which then reach the tumor cite under the actions of the waves propagated by the walls of the arteries with an external force such as a magnetic field or laser beams. The flow near the boundary of the artery may be treated as a boundary layer flow only for simplification as we consider here. In applied science, the flow and heat transfer of CNTs are usually described by systems of nonlinear differential equations. Due to nonlinearities, the exact solutions of such systems cannot be obtained in most cases. In this paper, an effective analytical procedure is proposed to deduce the exact solution of a system of nonlinear differential equations describing the effect of a convective heat condition on the flow and the heat transfer of carbon-nanotube suspended nanofluids with suction/injection in the presence of a magnetic field. The heat transfer equation is solved via applying Laplace transform and the solution is expressed in terms of the generalized incomplete gamma function. Also, it is proved that the present exact solutions for the flow and the heat transfer reduce to those in literature in the absence of the suction/injection and the convective parameters. The results declare that the temperature profiles are very sensitive regarding the value assigned to the convective parameter. Moreover, the effects of other physical parameters on the studied phenomena are displayed through graphs. Besides, possible applications of the current results have been also discussed.