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Effects of Cationic Surfactant on Fresh and Hardened Properties of Cement-Based Mortar

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Journal of Renewable Materials 2023年第5期11卷 2345-2365页

作者： Soumaya Zormati Fadhel Aloulou habib sammouda Laboratory of Energy and Materials LabEM-LR11ES34University of SousseSousseTunisia

The objective of this study is to analyze the effects of using surfactant(CTAB)and cellulose nanofibers(NFC)as an admixture in cement mortars.We examined composite properties as porosity,compression energy,thermal conductivity and hydration.The results showed that with the addition of 0.7%by weight of NFC per emulsion in the presence of a cationic surfactant(CTAB).The new material produced presented a dry porosity between 4.7%and 4.4%,compressive strength between 9.8 and 22.9 MPa,and thermal conductivity between 0.95 and 2.25 W·m^(−1)·K^(−1).Thus we show better mechanical and thermal performance than that traditional Portland cement mortar with a density similar.In addition,the mortar made by emulsion of ordinary portland cement,cellulose nanofiber and organophilic clay(OC)treated with cetyltrimethylammonium bromide(CTAB)obtained has good resistance under high temperature and water,as well as excellent thermal insulation performance under high temperature and humidity conditions.This study verified that the presence of NFC promotes hydration,leading to the production of more calcium silicate and portlandite gel.

关键词： Cement nanofiber cellulose organophile-clay thermal conductivity hydration surfactant compressive strength mortar

Influence and Dispersion of Nanofiber of Wood Modified on Properties of Cement Based Mortars

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Journal of Renewable Materials 2019年第7期7卷 631-641页

作者： Fadhel Aloulou Alila Sabrine habib sammouda LabEM-LR11ES34:Laboratory of Energy and Materials University of SousseTunisia LMSE:Laboratoire Sciences des Matériaux et Environnement University of SfaxTunisia

Wood nanofibers from industrial waste have been used as polymeric material to reinforce the cement paste to a content of up to 2%by weight of cement.The effect of the wood nanofibre content on the porosity,the compressive strength and the degree of hydration of the cement was studied.The results showed an improvement in compressive strength of over 50%with 1%of added fiberwood.Chemical modification of nanofiber wood by grafting alkyl chains to their surface can reduce the amount of water absorbed by the sample.Addition of an anionic additive(SDBS)to the mixing water improves the surface of the samples more and more by minimizing the pore size by emulsion effect,hence the water absorption decreases.The degree of hydration of the cement increased with the cellulose content containing nanofibrils.The analysis revealed that the presence of nanofibers favored the hydration of the cement by producing more calcium silicate gel and portlandite,probably the main reason for this improvement in compressive strength.

关键词： Cement nano-fiber wood modified adjuvant,surfactant emulsion

Stabilization and Evaluation of Modified Nanofiber Flour Wood on the Properties of Cement-Baszd Mortar

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Journal of Renewable Materials 2019年第8期7卷 763-774页

作者： Fadhel Aloulou Sabrine Alila habib sammouda Laboratory of Energy and Materials(LabEM):LR11ES34 Higher School of Science and Technology of Hammam SousseUniversity of SousseSousseTunisia Laboratoire Sciences des Matériaux et Environnement:LMSE Facultédes Sciences de SfaxUniversity of SfaxSfaxTunisia

The influence of nanofiberwood on the properties of the fresh condition of cement based mortars is not known in detail,despite recent advances in nanocellulose technology and it is related composite materials.Nanofiber wood from industrial waste,produced by high-pressure homogenization,was used as cement partial replacement for cement paste at a content ranging from 0%to 2%by weight of cement.The effect of the nanofiber wood content on the porosity,the compressive strength and the degree of hydration of the cement was investigated.Results have shown an improvement in the compressive strength by more than 50%with 1%of added fiber wood.The chemical modification of nanofibers wood by grafting of chains alkyls in their surfaces can reduce the quantity of water absorbed by the sample.The addition of an anionic additive(SDBS)in the water of mixing improves of more the surface of samples by minimizing the size of pores by emulsion effect,from where the absorption of water reduces.The degree of hydration of the cement has increased with the cellulose content containing nanofibrils.The analyze revealed that the presence of nanofiber wood favored the hydration of the cement by producing more calcium silicate gel and portlandite,probably the main reason for this improvement in compressive strength.

关键词： Cement nano-fiber adjuvant surfactant emulsion hydratation thermal conductivity

Some Advances in Applications of Lattice Boltzmann Method for Complex Thermal Flows

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Advances in Applied Mathematics and Mechanics 2010年第5期2卷 587-608页

作者： Ridha Djebali habib sammouda Mohammed El Ganaoui University of Tunis El-Manar FS of TunisDepartment of PhysicsLETTM1060 TunisTunisia CNRS/SPCTS UMR 6638FST of LimogesDepartment of Physics87060 LimogesFrance

Over the past two decades,there have been enormous advances in lattice Boltzmann(LB)numerical simulation and modelling.The lattice Boltzmann method has become a practical and promising tool for many fluid problems.A majority of recent studies have relied on numerical computations of isothermal flows.However,much less efforts have been devoted to complex thermal flows,such as flows in porous media subjected to external magnetic force,flows with temperature-dependent properties.In this paper,an overview is made based on some accomplishments in these numerical endeavours.Along with the paper’s sections,the state-of-the-art trend and the LBM advances in modelling and in computational aspects for specific classes of problems of major interest will be fully touched on.Concluding remarks are given and the axis of our future studies will be traced.

关键词： LB method Bifurcations and instability porous media flows plasma jets

纳米流体在平板上的湍流边界层和流体流动分析

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Journal of Central South University 2021年第11期28卷 3340-3353页

作者： AOUINET Hana DHAHRI Maher SAFAEI Mohammad Reza sammouda habib ANQI Ali E. Higher Private School of Engineering and Applied Technology(IHE-ESPITA) SousseTunisia Laboratory of Energy and Materials(LabEM)(LR11ES34) High School of Sciences and Technology of Hammam SousseSousse UniversityBP 4011Hammam SousseTunisia Department of Medical Research China Medical University HospitalChina Medical UniversityTaiwanChina Mechanical Engineering Department Faculty of EngineeringKing Abdulaziz UniversityJeddahSaudi Arabia Department of Mechanical Engineering College of EngineeringKing Khalid UniversityAbha 61421Saudi Arabia Research Center for Advanced Materials Science(RCAMS) King Khalid UniversityAbhaSaudi Arabia

对分别浸入3种纳米流体(ZnO-水,SiO_(2)-水,TiO_(2)-水)的平板近壁面流动的湍流边界层的对数规律进行数值分析。采用CFD程序对边界层和流体动力流动进行数值模拟。使用已发表的测量点对数值模型进行验证,结果表明一致性较好。对流速0.04... 详细信息

对分别浸入3种纳米流体(ZnO-水,SiO_(2)-水,TiO_(2)-水)的平板近壁面流动的湍流边界层的对数规律进行数值分析。采用CFD程序对边界层和流体动力流动进行数值模拟。使用已发表的测量点对数值模型进行验证,结果表明一致性较好。对流速0.04 m/s,0.4 m/s,4 m/s以及纳米颗粒浓度0.1%和5%的情况进行模拟。研究了纳米颗粒浓度对速度、温度分布、壁面剪切应力和湍流强度的影响。结果表明:沿势流层的黏性亚层、缓冲层和对数律层可以基于具有单壁距离区域的弯曲质量进行分析。可见,与其他区域相比,黏性亚层面积最大。另一方面,温度变化与热边界层厚度有关的区域在流速减小时也减小,热边界层离前缘越来越深,而纳米颗粒体积分数的增加对壁面剪切应力的影响较小。在所有情况下,边界层的厚度都随着流速的增加而减小,而纳米颗粒浓度的增加会使边界层的厚度增加。更准确地说,对数层在Y^(+)=50和Y^(+)=95之间最小。在所研究的纳米流体中,φ=5%时的边界层温度高于φ=0.1%时的边界层温度。而Y^(+)=1时,结果正好相反,φ=0.1%时的温度比φ=5%的更高。当流速分别为v=4,0.4,0.04 m/s时,湍流强度峰值分别出现在Y^(+)=100,Y^(+)=10和Y^(+)=8时。

关键词：湍流边界层纳米流体水动力流壁剪切应力湍流强度

Fast synthesis of gold nanoparticles by cold atmospheric pressure plasma jet in the presence of Au+ions and a capping agent

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Plasma Science and Technology 2024年第7期26卷 108-115页

作者： Tatiana habib José Mauricio A.CAIUT Bruno CAILLIER Laboratoire Diagnostics des Plasmas Hors Equilibre(DPHE) Universitéde ToulouseINU ChampollionAlbi 81000France Department of Chemistry The Nanomaterials and Luminescent Systems GroupFaculty of PhilosophyScience and Letters at Ribeirão PretoUniversity of São PauloRibeirão Preto-SP 14040-901Brazil

Homogeneous gold nanoparticles were synthesized under atmospheric pressure using a nonthermal helium plasma jet in a single-step process.A current power supply was used to generate the plasma discharge rich in diverse reactive species.These species induce rapid chemical reactions responsible for the reduction of the gold salts upon contact with the liquid solution.In this study,spherical and monodispersed gold nanoparticles were obtained within 5 min of plasma exposure using a solution containing gold(Ⅲ)chloride hydrate(HAuCl_(4))as a precursor and polyvinylpyrrolidone(PVP)as a capping agent to inhibit agglomerations.The formation of these metal nanoparticles was initially perceptible through a visible change in the sample's color,transitioning from light yellow to a red/pink color.This was subsequently corroborated by UVvis spectroscopy,which revealed an optical absorption in the 520-550 nm range for Au NPs,corresponding to the surface plasmon resonance(SPR)band.An investigation into the impact of various parameters,including plasma discharge duration,precursor and capping agent concentrations,was carried out to optimize conditions for the formation of well-separated,spherical gold nanoparticles.Dynamic light scattering(DLS)was used to measure the size of these nanoparticles,transmission electron microscopy(TEM)was used to observe their morphology and X-ray diffraction(XRD)was also employed to determine their crystallographic structure.The results confirm that homogeneous spherical gold nanoparticles with an average diameter of 13 nm can be easily synthesized through a rapid,straightforward,and environmentally friendly approach utilizing a helium atmospheric pressure plasma.

关键词： gold nanoparticles non-thermal plasma jet helium DBD

Fine Sand and Clay Sediment Acoustic Properties of the Novel Sediment Sample from the Arabian Sea:Experimental Investigations and Biot−Stoll Model Validation

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China Ocean Engineering 2024年第1期38卷 169-180页

作者： Shahabuddin SHAIKH HUANG Yi-wang ZHANG Ze-chuan habib Hussain ZUBERI National Key Laboratory of Underwater Acoustic Technology and College of Underwater Acoustic Engineering Harbin Engineering UniversityHarbin 150001China

The present study explores the physical and acoustic characteristics of fine sand and clay in novel seabed marine sediments from of Pakistan coastline of the Arabian Sea.The measured physical parameters included mean grain size,mass density,bulk density,salinity,porosity,permeability,pore size and mineralogical composition.Acoustic properties,including sound speed and attenuation,in the high frequency range of 90-170 kHz were analyzed.A controlled laboratory setup with the acoustic transmission method and Fourier transform techniques was utilized to examine the sound propagation and absorption of novel seabed sediments.The standard deviation of mean sound speed in fresh water was 0.75 m/s,and attenuation was observed in the range of 0.43 to 0.61 dB/m.The mean sound velocity in sand and clay varied from 1706 to 1709 m/s and 1602 to 1608 m/s,respectively.Corresponding average attenuation was observed at 80 to 93 dB/m in sandy sediments and from 31.8 to 38.6 dB/m in clayey sediments.Sound velocity variation within sandy sediment is low,consistent with expected results,and smaller than the predicted uncertainty.However,clay sediment exhibited a positive linear correlation and low sound speed variation.Attenuation increased linearly with frequency for both sediments.Finally,the laboratory results were validated by using the Biot−Stoll model.The dispersion of sound speed in sandy and clayey sediments was consistent with the predictions of the Biot−Stoll model.Measured attenuation aligned more with Biot−Stoll model predictions due to improved permeability,tortuosity and pore size parameter fitting.

关键词： physical and acoustic characteristics marine sediments sound speed attenuation Biot−Stoll model

Transfer learning from T1-weighted to T2-weighted Magnetic resonance sequences for brain image segmentation

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CAAI Transactions on Intelligence Technology 2024年第1期9卷 26-39页

作者： Imene Mecheter Maysam Abbod habib Zaidi Abbes Amira Brunel University LondonUK Geneva University Hospital GenevaSwitzerland Geneva University GenevaSwitzerland University of Groningen GroningenNetherlands University of Southern Denmark OdenseDenmark University of Sharjah SharjahUAE De Montfort University LeicesterUK

Magnetic resonance(MR)imaging is a widely employed medical imaging technique that produces detailed anatomical images of the human body.The segmentation of MR im-ages plays a crucial role in medical image analysis,as it enables accurate diagnosis,treatment planning,and monitoring of various diseases and conditions.Due to the lack of sufficient medical images,it is challenging to achieve an accurate segmentation,especially with the application of deep learning networks.The aim of this work is to study transfer learning from T1-weighted(T1-w)to T2-weighted(T2-w)MR sequences to enhance bone segmentation with minimal required computation resources.With the use of an excitation-based convolutional neural networks,four transfer learning mechanisms are proposed:transfer learning without fine tuning,open fine tuning,conservative fine tuning,and hybrid transfer learning.Moreover,a multi-parametric segmentation model is proposed using T2-w MR as an intensity-based augmentation technique.The novelty of this work emerges in the hybrid transfer learning approach that overcomes the overfitting issue and preserves the features of both modalities with minimal computation time and resources.The segmentation results are evaluated using 14 clinical 3D brain MR and CT images.The results reveal that hybrid transfer learning is superior for bone segmentation in terms of performance and computation time with DSCs of 0.5393±0.0007.Although T2-w-based augmentation has no significant impact on the performance of T1-w MR segmentation,it helps in improving T2-w MR segmentation and developing a multi-sequences segmentation model.

关键词： computer vision convolution image segmentation learning(artificial intelligence)

Metabolic dysfunction-associated steatotic liver disease heterogeneity: Need of subtyping

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World Journal of Gastrointestinal Pathophysiology 2024年第2期15卷 1-14页

作者： Shahid habib Department of Hepatology Liver Institute PLLCTucsonAZ 85716United States

Metabolic dysfunction-associated steatotic liver disease(MASLD)is a widespread global disease with significant health burden.Unhealthy lifestyle,obesity,diabetes mellitus(DM),insulin resistance,and genetics have been implicated in the pathogenesis of MASLD.A significant degree of heterogeneity exists among each of above-mentioned risk factors.Heterogeneity of these risk factors translates into the heterogeneity of MASLD.On the other hand,MASLD can itself lead to insulin resistance and DM.Such heterogeneity makes it difficult to assess the natural course of an individual with MASLD in clinical practice.At present MASLD is considered as one disease despite the variability of etiopathogenic processes,and we lack the consensus definitions of unique subtypes of MASLD.In this review,pathogenic processes of MASLD are discussed and a need of subtyping is recommended.

关键词： Metabolic dysfunctions-associated steatotic liver disease Visceral obesity Genetics Diabetes Insulin resistance