Ethanol to hydrocarbons using silver substituted polyoxometalates: Physicochemical and catalytic study

Mohamed Mokhtar,Tarek T. Ali,Sulaiman N. Basahel 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.1

Thermally stable and insoluble silver salts of 12-molybdophosphoric acid with varying amount of Agcations were prepared. XRD results indicated the presence of single phase of AgxH3xPMo12O40(0 < x < 3). FTIR and Raman results indicated that Ag was incorporated in the secondarystructure of Keggin ion. The catalytic conversion of ethanol increased in the order ofH3PMo > Ag2PMo > Ag1PMo > Ag3PMo. Pure H3PMo is highly selective to dimethyl ether formation;in contrast AgxH3-xPMo12O40 catalysts offered better ethylene selectivity. The pyridine adsorptionstudies revealed that increase of Ag incorporating led to increase the Lewis acid sites.

Preparation and characterization of ion selective membrane and its application for Cu2+ removal

Mohamed Mokhtar,Sarah E. Dickson,김영기,Waleed Mekky 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.60 No.-

Membranes are used in industrial wastewater treatment for the removal and recovery of heavy metals. A persistent challenge in heavy metals removal using membranes is the lack of selectivity for specific target ions, such as the removal and recovery of copper from other metal ions in industrial wastewater. This work reports the preparation of a new Cu(II)-selective ion-imprinted polymeric membrane. Membrane synthesis was conducted by applying an advanced immobilization method which comprises the preparation of polymerizable chelating monomer divinylbenzyl triethylenetetramine (diVB-TETA), the formation of the copper complex Cu-divinylbenzyl triethylenetetramine monomer (diVB-TETA-Cu), the polymerization/cross-linking of diVB-TETA-Cu within the Polyvinylidene fluoride (PVDF) pores to produce a copper-loaded membrane and finally the leaching of the copper (imprinting) from the membrane to produce ion-imprinted PVDF/diVB-TETA-Cu membrane. The chemical, elemental morphological properties of the synthesized ion-imprinted membrane were characterized by Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscope coupled with Energy dispersive X-ray spectroscopy (SEM-EDS), Proton nuclear magnetic resonance (1H NMR) and Carbon-13 nuclear magnetic resonance (13C NMR). To assess selective separation of Cu2+ from the mixture of Cu2+ and Ni2+, adsorption at different pH settings and diffusion permeation experiments were carried out. The results show that diVB-TETA-Cu was successfully synthesized and its immobilization through polymerization/cross-linking almost filled all PVDF pores. The PVDF/diVB-TETA-Cu membrane permeation flux ratio of Cu2+:Ni2+ is 3.78. The prepared membrane is suitable for Cu2+ ion selective separation processes.

A novel shear deformation theory for buckling analysis of single layer graphene sheet based on nonlocal elasticity theory

Mokhtar, Youcef,Heireche, Houari,Bousahla, Abdelmoumen Anis,Houari, Mohammed Sid Ahmed,Tounsi, Abdelouahed,Mahmoud, S.R. Techno-Press 2018 Smart Structures and Systems, An International Jou Vol.21 No.4

In this paper, a novel simple shear deformation theory for buckling analysis of single layer graphene sheet is formulated using the nonlocal differential constitutive relations of Eringen. The present theory involves only three unknown and three governing equation as in the classical plate theory, but it is capable of accurately capturing shear deformation effects, instead of five as in the well-known first shear deformation theory (FSDT) and higher-order shear deformation theory (HSDT). A shear correction factor is, therefore, not required. Nonlocal elasticity theory is employed to investigate effects of small scale on buckling of the rectangular nano-plate. The equations of motion of the nonlocal theories are derived and solved via Navier's procedure for all edges simply supported boundary conditions. The results are verified with the known results in the literature. The influences played by Effects of nonlocal parameter, length, thickness of the graphene sheets and shear deformation effect on the critical buckling load are studied. Verification studies show that the proposed theory is not only accurate and simple in solving the buckling nanoplates, but also comparable with the other higher-order shear deformation theories which contain more number of unknowns.

White mineral trioxide aggregate mixed with calcium chloride dihydrate: chemical analysis and biological properties

Hany Mohamed Aly Ahmed,Norhayati Luddin,Thirumulu Ponnuraj Kannan,Khairani Idah Mokhtar,Azlina Ahmad 대한치과보존학회 2017 Restorative Dentistry & Endodontics Vol.42 No.3

Objectives: This study aimed to evaluate the chemical and biological properties of fast-set white mineral trioxide aggregate (FS WMTA), which was WMTA combined with calcium chloride dihydrate (CaCl2·2H2O), compared to that of WMTA. Materials and Methods: Surface morphology, elemental, and phase analysis were examined using scanning electron microscope (SEM), energy dispersive X-ray microanalysis (EDX), and X-ray diffraction (XRD), respectively. The cytotoxicity and cell attachment properties were evaluated on human periodontal ligament fibroblasts (HPLFs) using methyl-thiazol-diphenyltetrazolium (MTT) assay and under SEM after 24 and 72 hours, respectively. Results: Results showed that the addition of CaCl2·2H2O to WMTA affected the surface morphology and chemical composition. Although FS WMTA exhibited a non-cytotoxic profile, the cell viability values of this combination were lesser than WMTA, and the difference was significant in 7 out of 10 concentrations at the 2 time intervals (p < 0.05). HPLFs adhered over the surface of WMTA and at the interface, after 24 hours of incubation. After 72 hours, there were increased numbers of HPLFs with prominent cytoplasmic processes. Similar findings were observed with FS WMTA, but the cells were not as confluent as with WMTA. Conclusions: The addition of CaCl2·2H2O to WMTA affected its chemical properties. The favorable biological profile of FS WMTA towards HPLFs may have a potential impact on its clinical application for repair of perforation defects.

The Impact of Deflection on the Sensing Response of Fiber Bragg Gratings Bonded to Graphene and PMMA Substrates

Younis Mohammed Salih,Mudhaffer Mustafa Ameen,Fahmi F. Muhammadsharif,Mohammad Fadhli Ahmad,Nor Aieni Haji Mokhtar,Ismael Mohammed Mohammed Saeed,Md. Nurul Islam Siddique,Ahmad Nazri Dagang,Salisa Abd 한국광학회 2020 Current Optics and Photonics Vol.4 No.2

The impact of graphene and poly(methyl methacrylate) (PMMA) substrates on the response of a fiber Bragg grating (FBG) due to mechanical deflection was investigated. For this purpose, four FBGs with grating lengths of 5, 15, 25, and 35.9 mm were utilized. Higher sensitivity was found for FBGs of larger grating length and for those bonded to graphene substrate. It was concluded that FBGs of smaller grating length (5 and 15 mm) were more sensitive in compression mode, while those of larger grating length (25 and 35.9 mm) were seen to be highly sensitive in tension mode.

White mineral trioxide aggregate mixed with calcium chloride dihydrate: chemical analysis and biological properties

Ahmed, Hany Mohamed Aly,Luddin, Norhayati,Kannan, Thirumulu Ponnuraj,Mokhtar, Khairani Idah,Ahmad, Azlina The Korean Academy of Conservative Dentistry 2017 Restorative Dentistry & Endodontics Vol.42 No.3

Objectives: This study aimed to evaluate the chemical and biological properties of fast-set white mineral trioxide aggregate (FS WMTA), which was WMTA combined with calcium chloride dihydrate ($CaCl_2{\cdot}2H_2O$), compared to that of WMTA. Materials and Methods: Surface morphology, elemental, and phase analysis were examined using scanning electron microscope (SEM), energy dispersive X-ray microanalysis (EDX), and X-ray diffraction (XRD), respectively. The cytotoxicity and cell attachment properties were evaluated on human periodontal ligament fibroblasts (HPLFs) using methyl-thiazoldiphenyltetrazolium (MTT) assay and under SEM after 24 and 72 hours, respectively. Results: Results showed that the addition of $CaCl_2{\cdot}2H_2O$ to WMTA affected the surface morphology and chemical composition. Although FS WMTA exhibited a non-cytotoxic profile, the cell viability values of this combination were lesser than WMTA, and the difference was significant in 7 out of 10 concentrations at the 2 time intervals (p < 0.05). HPLFs adhered over the surface of WMTA and at the interface, after 24 hours of incubation. After 72 hours, there were increased numbers of HPLFs with prominent cytoplasmic processes. Similar findings were observed with FS WMTA, but the cells were not as confluent as with WMTA. Conclusions: The addition of $CaCl_2{\cdot}2H_2O$ to WMTA affected its chemical properties. The favorable biological profile of FS WMTA towards HPLFs may have a potential impact on its clinical application for repair of perforation defects.

Wave dispersion properties in imperfect sigmoid plates using various HSDTs

Belaid Batou,Mokhtar Nebab,Riadh Bennai,Hassen Ait Atmane,Abdeldjebbar Tounsi,Mohammed Bouremana 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.33 No.5

In this paper, wave propagations in sigmoid functionally graded (S-FG) plates are studied using new Higher Shear Deformation Theory (HSDT) based on two-dimensional (2D) elasticity theory. The current higher order theory has only four unknowns, which mean that few numbers of unknowns, compared with first shear deformations and others higher shear deformations theories and without needing shear corrector. The material properties of sigmoid functionally graded are assumed to vary through thickness according sigmoid model. The S-FG plates are supposed to be imperfect, which means that they have a porous distribution (even and uneven) through the thickness of these plates. The governing equations of S-FG plates are derived employed Hamilton's principle. Using technique of Navier, differential equations of S-FG in terms displacements are solved. Extensive results are presented to check the efficient of present methods to predict wave dispersion and velocity wave in S-FG plates.

Electrodeposition of SnS Thin film Solar Cells in the Presence of Sodium Citrate

Kihal, Rafiaa,Rahal, Hassiba,Affoune, Abed Mohamed,Ghers, Mokhtar The Korean Electrochemical Society 2017 Journal of electrochemical science and technology Vol.8 No.3

SnS films have been prepared by electrodeposition technique onto Cu and ITO substrates using acidic solutions containing tin chloride and sodium thiosulfate with sodium citrate as an additive. The effects of sodium citrate on the electrochemical behavior of electrolyte bath containing tin chloride and sodium thiosulfate were investigated by cyclic voltammetry and chronoamperometry techniques. Deposited films were characterized by XRD, FTIR, SEM, optical, photoelectrochemical, and electrical measurements. XRD data showed that deposited SnS with sodium citrate on both substrates were polycrystalline with orthorhombic structures and preferential orientations along (111) directions. However, SnS films with sodium citrate on Cu substrate exhibited a good crystalline structure if compared with that deposited on ITO substrates. FTIR results confirmed the presence of SnS films at peaks 1384 and $560cm^{-1}$. SEM images revealed that SnS with sodium citrate on Cu substrate are well covered with a smooth and uniform surface morphology than deposited on ITO substrate. The direct band gap of the films is about 1.3 eV. p-type semiconductor conduction of SnS was confirmed by photoelectrochemical and Hall Effect measurements. Electrical properties of SnS films showed a low electrical resistivity of $30{\Omega}cm$, carrier concentration of $2.6{\times}10^{15}cm^{-3}$ and mobility of $80cm^2V^{-1}s^{-1}$.

Emerging polymeric-based material with photocatalytic functionality for sustainable technologies

Nur Shamimie Nadzwin Hasnan,Mohamad Azuwa Mohamed,Nornastasha Azida Anuar,Muhamad Firdaus Abdul Sukur,Siti Fairus Mohd Yusoff,Wan Nur Aini Wan Mokhtar,Zul Adlan Mohd Hir,Norshahidatul Akmar Mohd Shoha 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.113 No.-

A variety of polymer-based photocatalysts for the highest photocatalytic activity through various modificationsand improvements such as doping, treatment with the oxidising or reducing agent, and integratinganother nanomaterial into the polymer photocatalysts composite are extensively studied. Furthermore, the most common issues on polymer-based photocatalysts, including wide band gap andhigh recombination rate of charge carriers, still need to be improved to yield high photocatalytic activity. Besides hydrogen evolution through the water splitting system, focus also has been paid to photocatalyticfor CO2 reduction, photodegradation of pollutants, photocatalytic chemical synthesis, and photocatalyticnitrogen fixation. This review attempts to reveal the secret of properties, issues, and enhancements, principallyin polymer photocatalysts, besides highlighting the reason for polymeric material as a critical nonmetal-based photocatalyst for various photocatalytic reactions, as well as conducting polymeric materialwith photocatalytic functionality.

Study on stability and free vibration behavior of porous FGM beams

Riadh Bennai,Redhwane Ait Atmane,Fabrice Bernard,Mokhtar Nebab,Noureddine Mahmoudi,Hassen Ait Atmane,Salem Mohammed Aldosari,Abdelouahed Tounsi 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.45 No.1

In this paper, buckling and free vibration of imperfect, functionally graded beams, including porosities, are investigated, using a higher order shear strain theory. Due to defects during the manufacturing process, micro porosities may appear in the material, hence the appearance of this imperfection in the structure. The material properties of the beams are assumed to vary regularly, with power and sigmoid law, in the direction of thickness. A novel porosity distribution affecting the functionally graded volume fraction is presented. For the compact formulation used for cementite-based materials and already used in P-FGM, we have adapted it for the distribution of S-FGM. The equations of motion in the FG beam are derived using Hamilton's principle. The boundary conditions for beam FG are assumed to be simply supported. Navier's solution is used to obtain the closed form solutions of the FG beam. The numerical results of this work are compared with those of other published research to verify accuracy and reliability. The comparisons of different shear shape functions, the influence of porosity, thickness and inhomogeneity parameters on buckling and free vibration of the FG beam are all discussed. It is established that the present work is more precise than certain theories developed previously.