Green gold@chitosan nanocomposite via solid-state synthesis; a separable catalyst for reduction of Cr(IV)

Ahmed Atia,Yasser K. Abdel-Monem,A.H. Salama,Salah M. El-kousy,Wael H. Eisa 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.117 No.-

A clean and high-throughput synthesis of gold@chitosan nanocomposite using nontoxic oxalic acid as areducing agent was developed. The synthetic route was carried out in completely dry conditions, i.e. solid-state reaction. The gold nanoparticles were bound with chitosan through the hydroxyl and aminogroups, as confirmed by Fourier transform infrared spectroscopic analysis. Scanning and transmissionelectron microscopy imaging confirmed the formation of semi-spherical gold particles with an averagesize of 8–15 nm. The catalytic performance of the synthesized gold nanoparticles for the reduction ofchromium(IV) in the presence of formic acid was evaluated. The film-forming ability of chitosan enabledthe design of separable/reusable heterogeneous catalyst which is convenient for real industrial applications. The proposed solid-state synthetic route could be adapted to produce a wide variety of nanostructuredmaterials that are characterized by high-yield, greenness, and low cost in very simple steps.

Regional Precipitation Variability Associated with Zonal Movement of Indian Ocean High Pressure System

Bilal Ahmed Usmani,Saqib-Ur-Rehman,Syed Adnan Hussain,Kamran Khan,Atia Elahi 한국기상학회 2019 Asia-Pacific Journal of Atmospheric Sciences Vol.55 No.4

Several studies have linked ongoing austral winter drying conditions in southwest Western Australia (SWWA) to changes in regional and large scale sea level pressure. As the region bounded by SWWA occupies limited observation of a typical global climate model (GCM), it is not easy to infer the influence of global climate change during the drought inSWWA. In this study, we explore the relationships between early winter (May-Aug) rainfall in Kent river catchment (KRC), Southwestern Australia and Indian Ocean High Pressure system.We construct two objective indices of Indian Ocean High Pressure system (IOHPS), viz., (i) the intensity of Indian Ocean High Pressure (IOHP) and, (ii) the Indian Ocean High Longitude (IOHLN) using National Center of Environmental Prediction mean sea-level pressure (MSLP) reanalysis data. The station data of seasonal rainfall is obtained from Australian Bureau of Meteorology. A representative rainfall index for the KRC was built by averaging the seasonal rainfall three major stations for the period of 1951–2016. Significant inverse relationship is found between early wintertime precipitation in KRC, Southwestern Australia and the IOHP and IOHLN. The IOHPS accounts for more of the early winter (May–August) precipitation variation in KRC than the Southern Oscillation Index (SOI), Southern Annular mode (SAM) and Indian Ocean Dipole (IOD). Our significant findings suggest that strengthening of IOHP and zonal movement of IOHPS has a major contribution in decline of early winter precipitation in KRC.

An analytical solution for equations and the dynamical behavior of the orthotropic elastic material

Ramady, Ahmed,Atia, H.A.,Mahmoud, S.R. Techno-Press 2021 Advances in concrete construction Vol.11 No.4

In this article, an analytical solution of the dynamical behavior in an orthotropic non-homogeneity elastic material using for elastodynamics equations is investigated. The effects of the magnetic field, the initial stress, and the non-homogeneity on the radial displacement and the corresponding stresses in an orthotropic material are investigated. The analytical solution for the elastodynamic equations has solved regarding displacements. The variation of the stresses, the displacement, and the perturbation magnetic field have shown graphically. Comparisons are made with the previous results in the absence of the magnetic field, the initial stress, and the non-homogeneity. The present study has engineering applications in the fields of geophysical physics, structural elements, plasma physics, and the corresponding measurement techniques of magneto-elasticity.

Histochemical Localization of Essential Oils and Bioactive Substances in the Seed Coat of the Halophyte Crithmum maritimum L. (Apiaceae)

Abdallah Atia,Ahmed Debez,Zouhaier Barhoumi,Chedly Abdelly,Abderrazak Smaoui 한국식물학회 2009 Journal of Plant Biology Vol.52 No.5

Despite seeds and fruits of several halophytes being rich in essential oils and other bioactive substances, the histochemical characterization of these compounds has not received much attention. The aims of the present investigation were to localize the essential oils and the bioactive substances in the seed coat of the oilseed halophyte Crithmum maritimum L. Fruits were collected from the rocky coasts of Tabarka (NW of Tunisia, 36°57′ 12″ N, 08°45′18″ E). C. maritimum L. seed is shown to be surrounded by two envelopes: The first structure is a secretory envelope, consisting in about 20 canals. The second layer represents the endocarp. As revealed by fluorescence and light microscopy, the essential oils, O-dihydroxyphenols and flavonoids, known as bioactive compounds, were accumulated in the canals. The endocarp layer accumulated polysaccharides, O-dihydroxyphenols, and flavonoids. As a whole, these findings highlight the histochemical features and confirm the valuable quality of C. maritimum L. seeds.

Alanine and serine functionalized magnetic nano-based particles for sorption of Nd(III) and Yb(III)

Galhoum, Ahmed A.,Mahfouz, Mohammad G.,Atia, Asem A.,Gomaa, Nabawia A.,Abdel-Rehem, Sayed T.,Vincent, Thierry,Guibal, Eric Techno-Press 2016 Advances in environmental research Vol.5 No.1

Magnetic nano-based sorbents have been synthesized for the recovery of two rare earth elements (REE: Nd(III) and Yb(III)). The magnetic nano-based particles are synthesized by a one-pot hydrothermal procedure involving co-precipitation under thermal conditions of Fe(III) and Fe(II) salts in the presence of chitosan. The composite magnetic/chitosan material is crosslinked with epichlorohydrin and modified by grafting alanine and serine amine-acids. These materials are tested for the binding of Nd(III) (light REE) and Yb(III) (heavy REE) through the study of pH effect, sorption isotherms, uptake kinetics, metal desorption and sorbent recycling. Sorption isotherms are well fitted by the Langmuir equation: the maximum sorption capacities range between 9 and 18 mg REE $g^{-1}$ (at pH 5). The sorption mechanism is endothermic (positive value of ${\Delta}H^{\circ}$) and contributes to increase the randomness of the system (positive value of ${\Delta}S^{\circ}$). The fast uptake kinetics can be described by the pseudo-second order rate equation: the equilibrium is reached within 4 hours of contact. The sub-micron size of sorbent particles strongly reduces the contribution of resistance to intraparticle diffusion in the control of uptake kinetics. Metal desorption using acidified thiourea solutions allows maintaining sorption efficiency for at least four successive cycles with limited loss in sorption capacity.

Effects of Extrusion Variables on Functional and Nutritional Properties of Extruded Oat Products

Luiz Carlos Gutkoski,Ahmed Atia EI-Dash 한국식품영양과학회 1999 Preventive Nutrition and Food Science Vol.4 No.3

The purpose of this research was to study the effects of initial moisture levels and extrusion temperatures on dietary fiber, nitrogen solubility index, available lysine, and the in vitro protein digestibility of extruded oat products. The dehulled grains were ground in a Brabender Quadrumat Senior mill and the coarse fraction, with higher crude protein, lipids and dietary fiber were conditioned to various moisture levels (15.5~25.5%) and extruded in a Brabender single-screw laboratory extruder. The extrudates showed a higher amount of soluble dietary fiber (8.14%) than in the raw material. However, the extrusion process affected the nutritional value of the protein due to a decrease in available lysine with increased temperature. The in vitro protein digestibility was unaffected by initial moisture levels and the extrusion temperatures examined.

Physical characterization and radiation shielding features of B2O3-As2O3 glass ceramic

Mohamed Y. Hanfi,Ahmed K. Sakr,A.M. Ismail,Bahig M. Atia,Mohammed S. Alqahtani,K.A. Mahmoud 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.1

The synthetic B2O3eAs2O3 glass ceramic are prepared to investigate the physical properties and the radiation shielding capabilities with the variation of concentration of the As2O3 with 10, 20, 30, and 40%, respectively. XRD analyses are performed on the fabricated glasseceramic and depicted the improvement of crystallinity by adding As2O3. The radiation shielding properties are studied for the B2O3eAs2O3 glass ceramic. The values of linear attenuation coefficient (LAC) are varied with the variation of incident photon gamma energy (23.1e103 keV). The LAC values enhanced from 12.19 cm1e37.75 cm1 by raising the As2O3 concentration from 10 to 40 mol% at low gamma energy (23.1 keV) for BAs10 and BAs40, respectively. Among the shielding parameters, the halfevalue layer, transmission factor, and radiation protection efficiency are estimated. Furthermore, the fabricated samples of glass ceramic have low manufacturing costs and good shielding features compared to the previous work. It can be concluded the B2O3eAs2O3 glass ceramic is appropriate to apply in X-ray or low-energy gamma-ray shielding applications.

Effects of Extrusion Variable on Functional and Nutritional Properties of Extruded Oat Products

Gutkoski, Luiz Carlos,El-Dash, Ahmed Atia The Korean Society of Food Science and Nutrition 1999 Preventive Nutrition and Food Science Vol.4 No.3

The purpose of this research was to study the effects of initial moisture levels and extrusion temperatures on dietary fiber, nitrogen solubility index, available lysine, and the in vitro protein digestibility of extruded oat productes. The dehulled grains were ground in a Brabender quadrumat Senior mill and the coarse fraction, with higher crude protein, lipids and dietary fiber were conditioned on various mositre levels (15.5~25.5%) and extruded in a Brabender single-screw laboratory extruder. The extrudates showed a higher amount of soluble dietary fiber (8.14%) than in the raw material . However, the extrusion process affected the nutritional value of the protein due to a decrease in available lysine with increased temperature . The in vitro protein digestibility was unaffected by initial moisture levels and the extrusion temperatures examined.

Ziziphus spina-christi based bio-synthesis of Ag nanoparticles

Mervat F. Zayed,Wael H. Eisa,Yasser K. Abdel-Moneam,Salah M. El-kousy,Ahmed Atia 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.23 No.-

The bio-production of silver nanoparticles (Ag NPs) using Ziziphus spina-christi extract was studied as a novel, rapid, low-cost and eco-friendly route. The impact of experimental factors, such as the extract quantity, precursor concentration and pH on the size and size distribution of Ag NPs, was studied with the aid of UV–vis spectrophotometer and transmission electron microscope (TEM). The FTIR analysis was carried out to identify the functional groups in Ag NPs. The as-synthesized Ag NPs was used as a catalyst for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of NaBH4.