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Friction coefficient and microhardness of anodized aluminum alloys under different elaboration conditions

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Transactions of Nonferrous Metals Society of China 2015年第6期25卷 1950-1960页

作者： M.GUEZMIL w.bensalah A.KHALLADI K.ELLEUCH M.DEPETRIS-wERY H.F.AYEDI Laboratoire de Génie des Matériaux et Environnement (LGME) IUT Mesures Physiques d’Orsay-University of Paris-Sud 11

The effects of anodizing conditions （electrolyte, current density and temperature） on the friction coefficient and Vickers mierohardness of anodic oxide layers formed on A1 5754 and A1 1050A substrates were investigated. The studied properties were examined using DELTALAB HVS-1000 Vickers mierohardness tester and rotating pin on disc tribometer. It was established that the highest microhardness （〉HV 400） and the lowest friction coefficient （〈0.4） were obtained with the oxalic acid addition of 10 g/L at high current density of 3 A/dm2 and low temperature of 5 ~C. The presence of oxidized Mg through the anodic oxide layer formed on A1 5754 was examined using glow-discharge optical emission spectroscopy （GDOES）. The MgO was found to act negatively on the mechanical property of the layer. Finally, the scanning electron microscopy （SEM）, energy dispersive X-ray spectroscopy （EDS）, and atomic force microscopy （AFM） were used to characterize the anodic layer before and after friction tests. It is found that the wear mechanism is related to many aspects of the initial morphology, chemical composition of the layer （C, S and Mg）, porosity and internal stress.

关键词： aluminium alloy anodization friction coefficient microhardness dry sliding friction surface characterization

Tribological and Physicochemical Analysis of Squid Pen High-density Polyethylene Biocomposite for Medical Application

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Journal of Bionic Engineering 2022年第5期19卷 1481-1492页

作者： Besma Sidia walid bensalah Mechanical Engineering Laboratory LR99ES32National Engineering School of MonastirUniversity of MonastirMonastirTunisia

High-Density Polyethylene(HDPE)wear debris generated in the hip joint prothesis leads to its *** aim of this study was to evaluate the potential of Squid Pen(SP)on the tribological and physicochemical properties of HDPE *** filled with 0,5,10,15 and 20 wt.%SP were elaborated by hot compression *** tests were carried out using a reciprocating pin-on-disc *** hardness,Fourier-Transform infra-red(FTIR)analysis,Scanning Electron Microscopy(SEM)of the biocomposite were *** analysis results of the biocomposites showed that an increase in the crystallinity rate was obtained with the addition of SP *** 10 wt.%of SP has a significant effect on the hardness of the *** correlation between the friction coefficient and the wear resistance of the composite was *** 5 wt.%SP-HDPE biocomposite has the lowest friction coefficient value with a decrease in the specific wear rate,compared to the unfilled *** SEM results showed that SP wear debris played an important role as a third roller body at the interface reducing the friction coefficient of the *** was concluded that the HDPE biocomposite could be successfully reinforced with 5 wt.%of SP.

关键词： Squid pen biomaterial Tribological behaviours FTIR analysis wear morphology Bionic

Tribological Behavior of CoCr28Mo/CoCr28Mo Pair in the Presence of Bio-lubrication

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Journal of Bionic Engineering 2018年第4期15卷 703-712页

作者： Manel Guezmil walid bensalah Salah Mezlini Laboratoire de Genie Mecanique (LGM) ENIM Rue Ibn Eljazzar 5019 Monastir University Tunisia

The tribological behavior of the CoCr28Mo/CoCr28Mo pair was studied using pin-on-disc tribometer. Four bio-lubricants were re- tained including pure sesame oil, nigella oil, physiological solution （0.9% NaC1） and Hyalgan. Hyalgan is a sodium hyaluronate （20 mg/2 mL） pharmaceutical intra-articular injection used, in this study, as a reference. The Coefficient of Friction （CoF） and wear rate （K） of CoCr28Mo were computed after tribological tests. The tribological efficiency of vegetable oils with regard to their chemical compo- sition and structure was compared to Hyalgan. It is found that, the use of vegetable oils enhanced significantly the tribological behavior of CoCr28Mo/CoCr28Mo pair. The obtained results were correlated to the chemical structure of vegetable oils namely the Unsaturations Number （UN） of fatty acids constituting the oil. Microscopic and chemical characterization of CoCr28Mo pins and discs were conducted and the wear mechanism was discussed.

关键词： CoCr alloy friction coefficient wear resistance oil lubrication

Tribological Investigation of HDPE-cuttlebone and HDPE-red Coral Composites

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Journal of Bionic Engineering 2019年第6期16卷 1068-1079页

作者： Amira Salem walid bensalah Salah Mezlini Universite de Monastir Ecole Nationale d'Ingenieurs de Monastir(ENIM)Laboratoire de Genie Mecanique(LGM)LR99ES325019MonastirTunisia

In this paper,the tribological properties of cuttlebone(CB)-reinforced high density polyethylene(HDPE)and Red Coral(RC)-reinfbrced HDPE composites were *** composite specimens were prepared with a hot compression molding machine using different weight proportions of fillers blended with *** tribological behavior of the composite disks was studied using pin-on-disk tribometer under dry condition against stainless steel M30Nw *** coefficient of friction as well as wear rate were examined to study the effects of the two fillers on the tribological perfonnance of both *** wear tests,different composites were examined using a Scanning Electron Microscope(SEM).It was fbund that the use of cuttlebone(CB)and Red Coral(RC)as reinforcement improved the tribological properties of HDPE.

关键词： cuttlebone-reinforced HDPE red coral-reinforced HDPE wear rate friction coefficient wear mechanism

Thick and Dense Anodic Oxide Layers Formed on Aluminum in Sulphuric Acid Bath

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Journal of Materials Science & Technology 2010年第2期26卷 113-118页

作者： w. bensalah M. Feki M. wery H.F. Ayedi URCIM Department of Materials EngineeringNational School of Engineering IUT Orsay-Paris XI University Plateau du Moulon URCIM Department of Materials Engineering National School of Engineering

Thick and dense oxide layers were obtained on aluminium in sulphuric acid electrolyte. For this purpose, the methodology of experimental design was used. A three-variables Doehlert design （bath temperature, anodic current density, sulphuric acid concentration）, was achieved. In order to maximize the growth rate and the density of the anodic oxide layer, optimum path study was conducted. Under the determined optimal anodizing conditions （5.7℃, 3 ***-2,Csul=140 g.L-1）, the estimated response values were 0.86 μmin-1 and 3.12 ***-2 for growth rate and density, respectively. The morphology of optimum layer was examined by scanning electron microscopy （SEM）. The compactness of the optimum anodic layer can be correlated with its morphology revealed by SEM observations.

关键词： Sulphuric anodization Experimental design Growth rate Density

The contribution of mediated oxidation mechanisms in the electrolytic degradation of cyanuric acid using diamond anodes

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Journal of Environmental Sciences 2016年第7期28卷 115-123页

作者： Nasr bensalah Sondos Dbira Ahmed Bedoui Department of Chemistry and Earth Sciences College of Arts and Sciences Qatar University Department of Chemistry Faculty of Sciences of Gabes University of Gabes

In this work, the contribution of mediated oxidation mechanisms in the electrolytic degradation of cyanuric acid using boron-doped diamond（BDD） anodes was investigated in different electrolytes. A complete mineralization of cyanuric acid was obtained in Na Cl;however lower degrees of mineralization of 70% and 40% were obtained in Na2SO4 and Na Cl O4, respectively. This can be explained by the nature of the oxidants electrogenerated in each electrolyte. It is clear that the contribution of active chlorine（Cl2, HCl O, Cl O-）electrogenerated from oxidation of chlorides on BDD is much more important in the electrolytic degradation of cyanuric acid than the persulfate and hydroxyl radicals produced by electro-oxidation of sulfate and water on BDD anodes. This could be explained by the high affinity of active chlorine towards nitrogen compounds. No organic intermediates were detected during the electrolytic degradation of cyanuric acid in any the electrolytes, which can be explained by their immediate depletion by hydroxyl radicals produced on the BDD surface. Nitrates and ammonium were the final products of electrolytic degradation of cyanuric acid on BDD anodes in all electrolytes. In addition, small amounts of chloramines were formed in the chloride medium. Low current density（≤ 10 m A/cm2） and neutral medium（p H in the range 6–9） should be used for high efficiency electrolytic degradation and negligible formation of hazardous chlorate and perchlorate.

关键词： Electrolytic degradation Diamond anode Supporting electrolyte Mediated oxidation Cyanuric acid

Fenton treatment of olive oil mill wastewater—applicability of the method and parameters effects on the degradation process

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Journal of Environmental Sciences 2004年第6期16卷 942-944页

作者： bensalah Nasr Bedoui Ahmed Gadri Abdellatif Institut Supérieur des Sciences Appliquées et Technologie de Gabès Rue Amor Ibn Elkhattab Zrig 6072 Gabès TunisiaFaculté des Sciences de Gabès Cité Erriadh Zrig 6072 Gabès TunisiaEcole Nationale d'Ingénieurs de Gabès Zrig 6029 Gabès Tunisia

The low biodegradability of polyphenolic compounds typically found in olive processing indicated that biological treatment is not always successful in the treatment of olive oil mill wastewater in term of COD removal. In this study the results of investigations on the applicability of Fenton's reagent in the treatment of this effluent were discussed. The efficiency of this method was determined. 86 % of removal COD was obtained using 5 mol H 2O 2 and 0.4 mol Fe 2+ per liter of crude OMw. The main parameters that govern the complex reactive system, i.e., time, pH, [H 2O 2] and [Fe(II)] were studied.

关键词： olive oil mill wastewater Fenton's reagent organic compounds removal COD

Mechanical and Abrasive wear Properties of Anodic Oxide Layers Formed on Aluminium

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Journal of Materials Science & Technology 2009年第4期25卷 508-512页

作者： w. bensalah K. Elleuch M. Feki M. wery H.F. Ayedi Unit'e de Recherche de Chimie Industrielle et Mat'eriaux(URCIM) Departement of Materials EngineeringNational School of Engineering IUT Orsay-Paris XI University

Aluminium oxide coatings were formed on aluminium substrates in oxalic acid-sulphuric acid bath. Abrasion tests of the obtained anodic layers were carried out on a pin-on-disc machine in accordance with the ISO/DP 825 specifications. The rickets microhardness, D （HV0.2）, and the abrasion weight loss, wa （mg） were measured. Influence of oxalic acid concentration （Cox）, bath temperature （T） and anodic current density （J） on D and wa has been examined, and the sulphuric acid concentration （Csul） was maintained at 100 g.L-1. It was found that high microhardness and abrasive wear resistance of oxide layers were produced under low temperatures and high current densities with the addition of oxalic acid. The morphology and the composition of the anodic oxide layer were examined by scanning electron microscopy （SEM）, atomic force microscopy （AFM）, optical microscopy and glow-discharge optical emission spectroscopy （GDOES）. It was found that the chemistry of the anodizing electrolyte, temperature, and current density are the controlling factors of the mechanical properties of the anodic oxide layer.

关键词： Aluminium oxide Vickers microhardness Abrasive wear

A novel method for clustering cellular data to improve classification

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Neural Regeneration Research 2025年第9期20卷 2697-2705页

作者： Diek w.wheeler Giorgio A.Ascoli Center for Neural Informatics Structures&PlasticityKrasnow Institute for Advanced Study Bioengineering Department Volgenau School of Engineering George Mason University FairfaxVAUSA

Many fields,such as neuroscience,are experiencing the vast prolife ration of cellular data,underscoring the need fo r organizing and interpreting large datasets.A popular approach partitions data into manageable subsets via hierarchical clustering,but objective methods to determine the appropriate classification granularity are *** recently introduced a technique to systematically identify when to stop subdividing clusters based on the fundamental principle that cells must differ more between than within *** we present the corresponding protocol to classify cellular datasets by combining datadriven unsupervised hierarchical clustering with statistical *** general-purpose functions are applicable to any cellular dataset that can be organized as two-dimensional matrices of numerical values,including molecula r,physiological,and anatomical *** demonstrate the protocol using cellular data from the Janelia MouseLight project to chara cterize morphological aspects of neurons.

关键词： cellular data clustering dendrogram data classification Levene's one-tailed statistical test unsupervised hierarchical clustering