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51.
Sadra Mahmoudi Bahram Hashemi Shahraki 《Journal of Dispersion Science and Technology》2019,40(1):33-42
This paper concerns with developing of parameters which influence terminal velocities of air and CO2 bubbles in distilled water and kerosene pools. The objective of this study is to validate and correct the formulas that were developed by previous investigators for prediction of terminal velocities. The investigation revealed that the terminal velocity of a single rigid spherical bubble in Newtonian fluids can be developed by balancing of mechanical forces acting on the bubble. However, for large bubbles, because of deforming of the bubble which is a result of interfacial tension, the effect of surface tension should be considered in the terminal velocity prediction formula. By using PSO algorithm and plotting experimental data of terminal velocity against the size of gas bubbles, the suitable equation for each of systems was chosen. Results showed that Jamialahmadi model is more practical for terminal velocity prediction. Jamialahmadi model requires a modification to be utilized for air-kerosene, CO2-kerosene, air- distilled water and CO2-distilled water systems. The developed PSO algorithm model is accurate for prediction of experimental data with an average R2 value of 0.9722. 相似文献
52.
Chlorophyll b was extracted from Heliotropium europaeum plant, then immobilized on magnetic nanoparticles (Fe3O4@SiO2@Chl-Mg) and found as an efficient and green catalyst for the preparation of a variety of benzimidazoles and spirooxindoles in mild conditions. The catalyst was fully characterized by Fourier-transform infrared (FTIR), ultraviolet–visible (UV–vis) spectroscopy, X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), thermogravimetric (TGA), vibrating sample magnetometer (VSM), transmission electron microscopy (TEM), and dynamic light scattering (DLS) analyses. To prove the catalytic influence of Mg over the reactions, the catalytic activity of the demetalated chlorophyll b as well as some other control experiments was investigated. High to excellent yields were achieved for all entries, whether benzimidazole or spirooxindole derivatives at short reaction times. The catalyst could be recovered and reused for several consecutive runs by a simple external magnetic field without any considerable reactivity loss. The properties of the recovered catalyst were investigated by various analyses. Finally, the reasonable mechanisms were proposed for the reactions based on the literature. 相似文献
53.
54.
Slaheddine Chaabouni Slaheddine Kamoun Abdelaziz Daoud Tahar Jouini 《Journal of chemical crystallography》1997,27(7):401-404
The pentakis ethylenediammonium bis undecachlorodiantimonate(III) tetrahydrate salt is monoclinic with the following unit
cell dimensions:a=16.271(5) Å,b=13.004(4) Å,c=13.932(4) Å, β=111.72(2)°, space groupP21/c withZ=2. The structure was solved by Patterson methods and refined to a finalR value of 0.023 for 4435 reflections withF
0>4σ(F
0). The structure shows a layer arrangement perpendicular to thea axis: planes of the [Sb2Cl11]5− bioctahedra alternate with planes of [NH3(CH2)2NH3]2+ dications. The [Sb2Cl11]5− bioctahedra are connected through O−H...Cl hydrogen bonds, such that infinite chains of composition [Sb2Cl11(H2O]n
5n− are formed in the structure, parallel to the twofold axis. These chains are themselves interconnected by means of N−H...Cl
and O−H...Cl bonds originating from the [NH3(CH2)2NH3]2+ entities and the water molecules, respectively, and form a threedimensional network. 相似文献
55.
Slaheddine Chaabouni Slaheddine Kamoun Abdelaziz Daoud Tahar Jouini 《Journal of chemical crystallography》1991,27(7):401-404
The pentakis ethylenediammonium bis undecachlorodiantimonate(III) tetrahydrate salt is monoclinic with the following unit
cell dimensions:a=16.271(5) Å,b=13.004(4) Å,c=13.932(4) Å, β=111.72(2)°, space groupP21/c withZ=2. The structure was solved by Patterson methods and refined to a finalR value of 0.023 for 4435 reflections withF
0>4σ(F
0). The structure shows a layer arrangement perpendicular to thea axis: planes of the [Sb2Cl11]5− bioctahedra alternate with planes of [NH3(CH2)2NH3]2+ dications. The [Sb2Cl11]5− bioctahedra are connected through O−H...Cl hydrogen bonds, such that infinite chains of composition [Sb2Cl11(H2O]n
5n− are formed in the structure, parallel to the twofold axis. These chains are themselves interconnected by means of N−H...Cl
and O−H...Cl bonds originating from the [NH3(CH2)2NH3]2+ entities and the water molecules, respectively, and form a threedimensional network. 相似文献
56.
Pyrazolo[4,3‐d]pyrimidines, pyrazolo[4,3‐d]triazolino[4,3‐a]pyrimidines, 3‐(2‐thiazolyl)thiophenes, thiazolo[3,2‐a]pyridine and pyrazolo[1,5‐a]pyrimidines were synthesized from 2‐[4‐(3‐oxobenzo[f]‐2H‐chromen‐2‐yl)‐1,3‐thiazol‐2‐yl]ethanenitrile. The newly synthesized compounds were elucidated by elemental analysis, spectral data, chemical transformation and alternative synthesis route whenever possible. 相似文献
57.
Abdelghani Mahmoudi Silvia De Francia Prasanta Paul 《Journal of separation science》2023,46(21):2300424
Clarithromycin is a very important macrolide antibiotic used to treat bacterial infections in human and veterinary medicine. This study reports the development and validation of cost-effective, simple, precise, accurate, and robust high-performance liquid chromatography (HPLC) for the determination of clarithromycin (CLA) in tablets. Reversed-phase chromatography was conducted using a standard column at 55°C with ultraviolet detection at 215 nm. A mobile phase consisting of acetonitrile –2-methyl-2-propanol –potassium phosphate buffer was used at a flow rate of 1.0 mL/min. The proposed method displayed good linearity, precision, accuracy, robustness, and specificity. The present HPLC was compared with capillary electrophoresis and bioassay methods and the results indicated that there was no significant difference between these methods. Moreover, the obtained results demonstrated the validity of the isocratic HPLC, which allows reliable quantitation of CLA in pharmaceutical samples. Thus, it can be used as a substitute alternative methodology for the routine quality control of this medicine, in situations where other methods are less accessible in the laboratory. 相似文献
58.
Mahmoud G. Metwally Abdelaziz H. Benhawy Reda M. Khalifa Rasha M. El Nashar Marek Trojanowicz 《Molecules (Basel, Switzerland)》2021,26(21)
The increase of the global population and shortage of renewable water resources urges the development of possible remedies to improve the quality and reusability of waste and contaminated water supplies. Different water pollutants, such as heavy metals, dyes, pesticides, endocrine disrupting compounds (EDCs), and pharmaceuticals, are produced through continuous technical and industrial developments that are emerging with the increasing population. Molecularly imprinted polymers (MIPs) represent a class of synthetic receptors that can be produced from different types of polymerization reactions between a target template and functional monomer(s), having functional groups specifically interacting with the template; such interactions can be tailored according to the purpose of designing the polymer and based on the nature of the target compounds. The removal of the template using suitable knocking out agents renders a recognition cavity that can specifically rebind to the target template which is the main mechanism of the applicability of MIPs in electrochemical sensors and as solid phase extraction sorbents. MIPs have unique properties in terms of stability, selectivity, and resistance to acids and bases besides being of low cost and simple to prepare; thus, they are excellent materials to be used for water analysis. The current review represents the different applications of MIPs in the past five years for the detection of different classes of water and wastewater contaminants and possible approaches for future applications. 相似文献
59.
Rabia Djellouli Chokri Bekkey Abdelaziz Choutri Hayat Rezgui 《Mathematical Methods in the Applied Sciences》2000,23(17):1551-1583
An efficient method coupling a local boundary condition to a finite element technique is proposed to compute guided modes of optical fibres under the weak guidance assumptions. This method is designed to provide accurate solutions for optical fibres with no restriction on their shape as well as on their refractive index profile. Several numerical experiments are performed to demonstrate this point. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
60.