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Genesis of nanocrystalline Ho_2O_3 via thermal decomposition of holmium acetate: Structure evolution and electrical conductivity properties

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Journal of Rare Earths 2019年第2期37卷 185-192页

作者： bahaa m.abu-zied Abdullah m.Asiri Center of Excellence for Advanced materials Research (CEAmR) King Abdulaziz University Chemistry Department Faculty of Science King Abdulaziz University Chemistry Department Faculty of Science Assiut University

This study focuses on the preparation of nanostructured holmium oxide via the decomposition of holmium acetate precursor utilizing the non-isothermal strategy. Thermogravimetric analysis(TGA) was used to follow up the various thermal events involved in the decomposition process. Dehydration completes approximately at 150℃, which is followed by the decomposition of the anhydrous acetate leading to the formation of holmium oxide. Based on the TGA results the acetate precursor was heated non-isothermally at the temperature range of 150 e700℃. The obtained solids were characterized using powder X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), Fourier transform infrared spectroscopy(FT-IR), field-emission scanning electron microscopy(FE-SEm) and transmission electron microscopy(TEm). It is found that nanocrystalline Ho_2 O_3 starts to form at 500℃ and presents the only phase detected at the 500 e700℃ range. The electrical conductivity of the solids that form at the temperature range of 300 e700℃ was investigated. The obtained values were correlated with the observed structural modifications accompanying the heat treatment. The electrical conductivity of the Ho_2 O_3 samples prepared at 500, 600 and 700℃ reaches the values of 1.92 × 10^(-7), 1.61 × 10^(-7) and 8.33 × 10^(-8) Ω^(-1)cm^(-1) at a measuring temperature of 500℃, respectively. These values are potentially advantageous for high-resistivity devices.

关键词： Nanocrystalline Ho2O3 Thermal decomposition Ho2O3 Holmium oxide Rare earth oxides Nanomaterials

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Synthesis of Dy_2O_3 nanoparticles via hydroxide precipitation: effect of calcination temperature

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Journal of Rare Earths 2014年第3期32卷 259-264页

作者： bahaa m.abu-zied Abdullah m.Asiri Chemistry Department Faculty of Science King Abdulaziz University Center of Excellence for Advanced materials Research (CEAmR) King Abdulaziz University Chemistry Department Faculty of Science Assiut University

This work described the preparation of dysprosium oxide, Dy203, nanoparticles using the homogeneous precipitation method. Dy3＋ ions were precipitated using NaOH solution. The obtained product was filtered, dried, and then calcined for 1 h at the temperature range of 300-700 ℃ in static air. The calcination temperature of the Dy-precttrsor was chosen based on its decomposi- tion as indicated by the TGA analysis. The crystalline structure and surface morphology of the calcined solids were studied by X-ray diffraction （XRD）, field emission scanning electron microscopy （FE-SEm）, transmission electron microscopy （TEm） and X-ray pho- toelectron spectroscopy （XPS）. The obtained results revealed that Dy203 with crystallites size of 11-21 nm was formed at 500 ℃. Such value increased to 25-37 nm for the sample calcined at 700 ℃.

关键词： nanocrystalline dysprosium oxide Dy203 precipitation method Dy203 nanoparticles rare earths

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Fabrication,characterization,and electrical conductivity properties of Pr_6O_(11) nanoparticles

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Journal of Rare Earths 2013年第7期31卷 701-708页

作者： bahaa m.abu-zied Youssef A.mohamed Abdullah m.Asiri Chemistry Department Faculty of ScienceKing Abdulaziz UniversityP.O.Box 80203Jeddah 21589Saudi Arabia Chemistry Department Faculty of ScienceAssiut University71516 AssiutEgypt Center of Excellence for Advanced materials Research(CEAmR) King Abdulaziz UniversityP.O.Box 80203Jeddah 21589Saudi Arabia

PrrOll nanoparticles were obtained by subsequent thermal decomposition of the as-prepared precipitate formed under ambient temperature and pressure using NaOH as precipitant. The calcination process was affected, for 1 h in static air atmosphere, at 400-700 ℃ temperature range. The different samples were characterized using X-ray diffraction （XRD）, transmission electron microscopy （TEm）, field emission scanning electron microscopy （FE-SEm）, thermogravimetric analysis （TGA）, in situ electrical conductivity, and N2 adsorption/desorption. The obtained results demonstrated that nano-crystalline Pr6O11, with crystallites size of 6-12 nm, started to form at 500 ℃. Such value increased to 20-33 nm for the sample calcined at 700℃. The as-synthesized PrrOll nanoparticles presented high electrical conductivity due to electron hopping between Pr（III）-Pr（IV） pairs.

关键词： nanocrystalline praseodymium oxide Pr6O11 nano structured materials electrical conductivity rare earths

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纯相和镍取代的Co_3O_4尖晶石催化剂用于N_2O直接分解(英文)

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催化学报 2014年第7期35卷 1105-1112页

作者： bahaa m.abu-zied Soliman A.Soliman Sarah E.Abdellah Chemistry Department Faculty of ScienceAssiut University

A series of NixCo1-xCo2O4(0 ≤ x ≤ 1) spinel catalysts were prepared by the co-precipitation method and used for direct N2O decomposition. The decomposition pathway of the parent precipitates was characterized by thermal analysis. The catalysts were calcined at 500 °C for 3 h and characterized by powder X-ray diffraction, Fourier transform infrared, and N2 adsorption-desorption. Nickel cobaltite spinel was formed in the solid state reaction between NiO and Co3O4. The N2O decomposition measurement revealed significant increase in the activity of Co3O4 spinel oxide catalyst with the partial replacement of Co2+ by Ni2+. The activity of this series of catalysts was controlled by the degree of Co2+ substitution by Ni2+, spinel crystallite size, catalyst surface area, presence of residual K+, and calcination temperature.

关键词：氧化物催化剂四氧化三钴尖晶石型直接分解 N2O 镍氧化亚氮二氧化碳

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Robust malicious Executable Detection Using Host-Based machine Learning Classifier

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Computers, materials & Continua 2024年第4期79卷 1419-1439页

作者： Khaled Soliman mohamed Sobh Ayman m.bahaa-Eldin Department of Computer and Systems Engineering Ain Shams UniversityCairo11517Egypt Department of Computer Engineering Technology ElSewedy University of TechnologyCairo44629Egypt

The continuous development of cyberattacks is threatening digital transformation endeavors worldwide and leadsto wide losses for various organizations. These dangers have proven that signature-based approaches are insufficientto prevent emerging and polymorphic attacks. Therefore, this paper is proposing a Robust malicious ExecutableDetection (RmED) using Host-based machine Learning Classifier to discover malicious Portable Executable (PE)files in hosts using Windows operating systems through collecting PE headers and applying machine learningmechanisms to detect unknown infected files. The authors have collected a novel reliable dataset containing 116,031benign files and 179,071 malware samples from diverse sources to ensure the efficiency of RmED *** most effective PE headers that can highly differentiate between benign and malware files were selected totrain the model on 15 PE features to speed up the classification process and achieve real-time detection formalicious executables. The evaluation results showed that RmED succeeded in shrinking the classification timeto 91 milliseconds for each file while reaching an accuracy of 98.42% with a false positive rate equal to 1.58. Inconclusion, this paper contributes to the field of cybersecurity by presenting a comprehensive framework thatleverages Artificial Intelligence (AI) methods to proactively detect and prevent cyber-attacks.

关键词： Portable executable malware intrusion detection cybersecurity zero-day threats Host IntrusionDetection System(HIDS) machine learning Anomaly-based Intrusion Detection System(AIDS) deep learning

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Ultralong hydroxyapatite-based forward osmosis membrane for freshwater generation

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Frontiers of Chemical Science and Engineering 2024年第9期18卷 37-49页

作者： mohamed Gamal Gomaa Hamdy maamoun Abdel-Ghafar Francesco Galiano Francesca Russo Alberto Figoli El-Sayed Ali Abdel-Aal Abdel-Hakim Taha Kandil bahaa Ahmed Salah Central metallurgical Research and Development Institute(CmRDI) 11421 CairoEgypt Chemistry Department Faculty of ScienceHelwan University11795 CairoEgypt Institute on membrane Technology(CNR-ITm) 87036 RendeItaly

Increasing global water shortages are accelerating the pace of membrane manufacturing,which generates many environmentally harmful *** challenges need a radical rethink of developing innovative membranes that can address freshwater production without generating environmentally harmful *** work utilized the synthesized ultra-long hydroxyapatite(UHA)by the solvothermal method using the green solvent oleic acid in preparing UHA-based forward osmosis *** membranes were developed using different loading ratios of graphene oxide(GO)by vacuum-assisted filtration *** prepared GO/UHA membranes were identified using X-ray diffraction,scanning electron microscope,Fourier-transform infrared spectroscopy,and X-ray photoelectron *** contact angle and pore size distribution were determined for the obtained GO/UHA *** obtained hierarchical porous structure in the prepared membranes with interconnected channels results in a stable water flux with reverse salt *** best water flux rate of 42±2 L·m^(–2)·h^(–1)was achieved using the 50 mg GO/UHA membrane,which is 3.3 times higher than the pristine membrane,and a reverse salt flux of 67 g·m^(-2)·h^(–1).The obtained results showed a promising capability of a new generation of sustainable inorganic-based membranes that can be utilized in freshwater generation by energy-efficient techniques such as forward osmosis.

关键词： forward osmosis ultra-long hydroxyapatite graphene oxide inorganic-based membrane

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碱促进的钴酸镁催化剂上的氧化亚氮分解(英文)

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催化学报 2011年第2期32卷 264-272页

作者： bahaa m. abu-zied Chemistry Department Faculty of ScienceAssiut University

The direct decomposition of N2O was investigated over a series of magnesium cobaltite catalysts,mgxCo1-xCo2O4(0.0 ≤ x ≤ 1.0) ,which were prepared by the thermal decomposition of stoichiometric amounts of magnesium hydroxide and cobalt acetate. The thermal genesis of the different catalysts from their precursors was explored using thermogravimetric analysis,differential thermal analysis,and X-ray diffraction. Texture analysis was carried out using N2 adsorption at -196 °C. We found that all the catalysts that were calcined at 500 °C have a spinel structure. N2O decomposition activity was found to increase with an increase in the spinel structure's magnesium content. The influence of alkali cation promoters(Li,Na,K,and Cs) on the activity of the most active catalyst in the mgxCo1-xCo2O4 series,i.e. mgCo2O4,was also investigated. The sequence of the promotional effect was found to be: un-promoted moted catalyst. The reason for the increase in activity for the added alkali cations was electronic in nature. Additionally,the dependence of the activity on the K/Co ratio was also determined. The highest activity was obtained for the catalyst with a K/Co ratio of 0.05. A continuous decrease in activity was obtained for higher K/Co ratios. This decrease in activity was attributed to the elimination of mesoporosity in the catalysts with K/Co ratios > 0.05,based on N2 adsorption and scanning electron microscopy results.

关键词： nitrous oxide cobalt oxide magnesium cobaltite spinel alkali promotion

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The role of alkali promoters in enhancing the direct N_2O decomposition reactivity over NiO catalysts

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Chinese Journal of Catalysis 2015年第11期36卷 1837-1845页

作者： bahaa m. abu-zied 阿卜杜勒阿齐兹国王大学高级材料杰出研究中心沙特阿拉伯吉达21589 艾斯尤特大学理学院化学系埃及艾斯尤特71516 阿卜杜勒阿齐兹国王大学理学院化学系沙特阿拉伯吉达21589

Direct N2O decomposition has been investigated over bare NiO and a series of its alkali-promoted catalysts. These catalysts were characterized by X-ray diffractometry, X-ray photoelectron spectroscopy （XPS） and field emission scanning electron microscopy. XPS analysis revealed that surface nickel is present in three forms： metal particles, NiO and Ni（OH）2. It is suggested that nickel（0） valent atoms are essential for the interaction with N2O molecules at the catalyst surfaces. Bare NiO exhibited a very low N2O decomposition reactivity. However, the alkali-containing catalysts exhibited a marked activity enhancement.

关键词： N2O decomposition Greenhouse gas NiOAlkali-promotion Activity enhancement

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Results of Open Surgical Treatment of Humeral Paddle Fractures about 63 Cases

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Open Journal of Orthopedics 2024年第1期14卷 83-91页

作者： mansi zied Chermiti Wajdi Rbai Hedi Saadana Jacem Zaidi Bacem Sindi Sihem Gazzah Wael Department of Orthopedics-Traumatology Ibn El Jazzar Hospital of Kairouan Kairouan Tunisia Department of Orthopaedics-Traumatology Sahloul Hospital of Sousse Sousse Tunisia Department of Orthopedics-Traumatology Fattouma Bourguiba Hospital of Monastir Monastir Tunisia Department of General Surgery Ibn El Jazzar Hospital of Kairouan Kairouan Tunisia Department of Urology Ibn El Jazzar Hospital of Kairouan Kairouan Tunisia

Fractures of the humeral paddle, common to young adults, are most often complex, linked to violence and an increase in road accidents. The objective of our work is to evaluate our functional results, in the medium term, correlated with a review of the literature. This is a retrospective study of 63 patients, carried out in the traumatology-orthopedics department 1 of the IBN EL JAZZAR hospital in KAIROUAN, over a period of 7 years from January 2015 to December 2021. The average age of patients was 39 years (17 - 68 years). Predominantly male. The etiologies are dominated by falls and accidents on public roads. Fractures are classified according to the müller and Allgöwer classification where type C is found in 51% of cases. All our patients undergo an olecranon osteotomy in 71% of cases. Osteosynthesis using a Lecestre plate combined with screwing or plugging is used in 84% of cases. The evolution is marked by complications observed in eight patients (16%), including two cases of sepsis, four cases of elbow stiffness (8%), one case of joint callus and one case of pseudarthrosis. Our results are evaluated according to the mayo Elbow Performance Score, they are excellent and good in 71% of cases, average in 18% of cases and poor in 11% of cases. Fractures of the humeral paddle are fractures with a satisfactory functional prognosis, requiring ad integrum anatomical restoration and solid osteosynthesis allowing early rehabilitation of the elbow. One case of joint callus and one case of pseudarthrosis.

关键词： Fracture Humeral Paddle Surgical Treatment

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microstructure and mechanical Properties of Nano-crystalline Al-8 wt pct Ni Alloy

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Journal of materials Science & Technology 2006年第5期22卷 605-610页

作者： m.Abou zied Physics Department Faculty of Science South Valley UniversityQena 83511Egypt

microstructure and mechanical properties of ball-milled Al-8 wt pct Ni ribbon have been investigated by X-ray diffraction （XRD） and continuous Vickers hardness test, respectively. The results indicate that, the main phases of this alloy are α-Al and orthorhombic-Al3Ni. The lattice parameter of α-Al increases with increasing milling time. From the elastic constant of Al, the average contrast factors of the （111）, （200）, （220）, （311） and （222） Bragg＇s reflections for pure edge and pure screw dislocations in fcc crystals with α/2〈110〉{111} slip system were calculated. The average grain size and dislocation parameters as a function Of milling time have been investigated using the modified Williamson-Hall plot and the Warren-Averbach equation, *** attempt has been made to correlate the micro-hardness of milled ribbon with their grain size through the Hall-Patch relationship：HV0.01 = 742.45 〈 D 〉^-1/2 ＋401.55 （kg/mm^2）.

关键词： Aluminum microstructure Property X-ray diffraction

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