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

The use of Persea americana has been studied as an alternative source of activated carbon for the removal of dyes from wastewater. Chemical activation using phosphoric acid was employed for the preparation of the activated carbon (C-PAN). The BET surface area and the total pore volumes were found to be 1593 m²/g and 1.053 cm³/g, respectively. This study investigates the effect of some parameters like, dye concentration, adsorbent dose, contact time and pH for the best comprehension of the adsorption manner. Adsorption kinetic follows pseudo-second order kinetic model. Langmuir and Freundlich isotherms models were used to analyze the adsorption equilibrium data and the best fits to the experimental data were provided by Langmuir model. Maximum adsorption capacity is equal to 400 mg/g of Basic Yellow 28 onto the activated carbon derived from Persea americana. Thermodynamic parameters, such as standard Gibbs free energy (ΔG⁰), standard enthalpy (ΔH⁰) and standard entropy (ΔS⁰) has been calculated. The adsorption process was found to be spontaneous and exothermic process.

This study shows that the activated carbon provided from Persea americana can be an alternative to the commercially available adsorbents for dyes removal from liquid solutions.

Herbal medicines are widely accepted as a primary source of healthcare due to their natural origin. However, this widespread popularity is counterbalanced with the lack of relevant research. The need to account for this deficiency motivated the present study which aims at (1) assessing physicians’ knowledge and attitude toward herbal medicines, (2) determining to what extent herbal medicines are utilized by physicians in the Kingdom of Bahrain, and (3) highlighting the main factors that may facilitate or hinder the utilization of herbal medicines. A cross-sectional study was conducted to cover 96 physicians conveniently sampled from different departments among one public and two private hospitals. The main tool that was used to gather the required data was a self-administered questionnaire that has been specifically developed by the researchers to address the study objectives. The collected data were processed by the statistical package for social sciences SPSS (version 18). The study found that 64.6% of the participated physicians have generally basic knowledge on herbal medicines, and half of them acquired their knowledge from experience. Moreover, the results showed a tendency by physicians to use herbal medicines personally more frequently than prescribing them to the patients. Interestingly, the majority (91.7%) of the participants showed a desire to enhance their knowledge with regard to herbal medicines. They ascertained that the rational use of herbal medicines is hindered by poor quality control (65.6%) and limited information on their adverse events (62.5%). The physicians claimed that the availability of sufficient knowledge (68.8%) beside the low cost (66.7%) are major facilitating factors toward utilizing herbal medicines.

To isolate fungal communities from coastal areas of the Red Sea in Saudi Arabia and identify and classify them by molecular techniques. Samples were collected from the seaside of the Red Sea in Jeddah, Saudi Arabia during March 2012 and stored in sterile screw cap bottles for further analysis. Phenotypic and genotypic characterization of fungal isolates were done using standard techniques. Eight fungal genera including Aspergillus, Penicillium, Thielavia, Fusarium, Emericella, Cladosporium, Scytalidium and Alternaria. Most isolated fungi showed significant growth on petroleum media and were thus considered capable of biodegradation of crude oil based substances. The fungal genera isolated from the Red Sea had 97–100% similarity with the related fungi recorded in the GenBank in which they were deposited. The morphological and molecular structure of these marine fungal isolates closely resembles their terrestrial counterparts in the GenBank. The capabilities of these fungal species to utilize petroleum as a source of carbon speaks to future applications in which marine fungi may be utilized in the breakdown of petroleum-based waste in an ecologically efficient manner.

This paper presents a semi-analytical method for solving fractional differential equations with strong terms like (exp, sin, cos,…). An auxiliary parameter is introduced into the well-known Picard’s method and so called controlled Picard’s method. The proposed approach is based on a combination of controlled Picard’s method with Simpson rule. This approach can cover a wider range of integer and fractional orders differential equations due to the extra auxiliary parameter which enhances the convergence and is suitable for higher order differential equations. The proposed approach can be effectively applied to Bratu’s problem in fractional order domain to predict and calculate all branches of problem solutions simultaneously. Also, it is tested on other fractional differential equations like nonlinear fractional order Sine-Gordon equation. The results demonstrate reliability, simplicity and efficiency of the approach developed.

Using the well-known solitary wave ansatz method, we obtain new exact bright and dark soliton solutions for two nonlinear Schrödinger equations, namely, the perturbed nonlinear Schrödinger equation with the Kerr law nonlinearity and a higher order nonlinear Schrödinger equation which describe the propagation of ultra short pulses in nonlinear optical fibers. The parameters of the soliton envelope (amplitude, width, velocity) are obtained as a function of the dependent model coefficients. Comparing the new solutions for these two equations with the well-known results are given.

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.

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.

The purpose of this article is to generate the closed form traveling wave solutions of some nonlinear partial differential equations namely; the KdV equation and the modified KdV equation using the recently established rational (G′/G)-expansion method. By this method, new and further general closed form solutions expressed by three types of functions as for instance hyperbolic, trigonometric and rational function solutions are found. The basic ideas presented in this article and the obtained solutions might be useful to analyze the shallow water waves, ion acoustic waves in plasma, acoustic waves on a crystal lattice and the role of nonlinear dispersion in the formation of structures like liquid drops.

A spectrofluorimetric method based on complex formation between Zn²⁺ ions and 5-(4-flourophenyl)-quinolin-8-ol has been developed for the rapid determination of trace levels of zinc ions. The method is sensitive and selective. The complex formed emit strongly at 535 nm with excitation wavelength at 394 nm. Complexation formation was optimized by studying the effect of pH, molar ratio of the metal to the ligand and the type of buffers. The study indicated that maximum complexation resulted when the pH of the mixture was maintained at 8.0 with 0.2 M carbonate buffer and metal to ligand was at a stoichiometric ratio of 1:2. Under the optimum conditions, the detection limit was 3 ppb. Appropriate validation of the method, yielded acceptable relative standard deviations of less than 2% (n = 5). The method was applied to the trace determination of Zn²⁺ ions in tap water, mineral water, fresh milk and cream samples successfully.

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.