WorldCat Identities

Rharbi, Yahya

Overview
Works: 9 works in 11 publications in 2 languages and 18 library holdings
Roles: Thesis advisor, Opponent, Author
Publication Timeline
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Most widely held works by Yahya Rharbi
DEFORMATION DES NANOCOMPOSITES DUR/MOU OBSERVEE PAR DNPA by Yahya Rharbi( Book )

2 editions published in 1995 in French and held by 3 WorldCat member libraries worldwide

LA PREMIERE PARTIE DE LA THESE EST CONSACREE A L'ETUDE DES FILMS CELLULAIRES DE LATEX BIPHASIQUE. NOUS NOUS SOMMES INTERESSES A L'ANALYSE DE DEFORMATION PAR DIFFUSION DE NEUTRON AUX PETITS ANGLES DNPA. LES CELLULES SONT CONSTITUEES DE CURS EN POLYMERE HYDROPHOBE ET ENTOURES D'UNE COUCHE HYDROPHILE (MEMBRANE). MECANIQUEMENT, NOUS DISTINGUONS SUIVANT LE MILIEU DE DEFORMATION DEUX SITUATIONS EXTREMES: SOIT LA PARTIE CONNEXE EST DURE ENTOURANT DES INCLUSIONS MOLLES, SOIT LA PARTIE CONNEXE EST MOLLE ENTOURANT DES INCLUSIONS DURES. DANS LE PREMIER CAS LA DEFORMATION EST HOMOGENE ALORS QUE DANS LE SECOND CAS ELLE EST HETEROGENE. DANS LA SECONDE PARTIE DE LA THESE, NOUS AVONS GENERALISE LES EFFETS OBSERVES A D'AUTRES COMPOSITES DUR/MOU, EN PARTICULIER LE SYSTEME DE POLYMERE RENFORCE PAR LA SILICE. LES FILMS SONT FAITS PAR SECHAGE D'UNE DISPERSION DE LATEX ET SILICE. LA REPARTITION DE LA SILICE DANS LE FILM EST OBSERVABLE PAR DNPA ET MICROSCOPIE ELECTRONIQUE A CAUSE DU BON CONTRASTE SILICE/LATEX. LA SILICE EST ALORS DISPERSEE DANS LE FILM A L'ECHELLE DE LA PARTICULE. LES DEPLACEMENTS DES PARTICULES DURES, OBSERVEES AU COURS DE L'ETIREMENT DES FILMS, SONT REPRODUITES PAR SIMULATION NUMERIQUE. NOUS OBSERVONS DES CISAILLEMENTS LOCALES ENTRE PARTICULES DURES EN REPONSE A UNE FORTE COMPRESSION LATERALE
Les études de la dynamique du système micellaire P103/Eau et système de rhéoépaississement CTA-n-Fluorobenzoato. by Gabriel Landazuri Gomez( )

1 edition published in 2013 in French and held by 2 WorldCat member libraries worldwide

This thesis aims to understand the effect of the dynamics of copolymer micelles on their rheological properties. Indeed amphiphilic copolymers can self-assemble in water to form various micellar microstructures spherical, cylindrical or lamellar. Their dynamic is a critical parameter to define their range of applications, particularly in the transport of drugs and in the synthesis of mesostructured materials. Micelles are structured continuous: they can form and dissociate into monomers, merge or fragment. We have developed a method based on fluorescence to probe directly collective micellar dynamics of fusion and fission in a number of triblock copolymers of PEO -PPO -PEO family.This thesis focuses on the study of micellar systems formed by triblock copolymers (nonionic surfactants) and cationic surfactants at concentrations and temperatures where spherical micelles and rod like micelles are formed. Such structures may be formed spontaneously when the system is subjected to appropriate conditions of concentration and temperature or to the induction of these by adding inorganic or organic salts, or by applying shear stresses to the surfactant/water system.The technique of dynamic light scattering (DLS) was used to evaluate the transition of the structure in micellar solutions by changing the temperature and the structure of the system itself at given concentration - temperature conditions.Stress relaxation experiments were performed where temporary relaxation of stress is measured after a momentary deflection in aqueous solutions of P103. The relaxation times (or rate) are compared with those obtained by light scattering and their relation to the size of the micelles is shown. The stress relaxation presented a Maxwelian behavior. The relaxation times showed temperature dependence with characteristic behavior schemes for elongated and spherical micelles respectively.In this work, we also study the micellar system CTAnFB where “n” is substitution of fluorine in the ortho position (F:2) meta ( F:3) and para (F:4), namely CTAortoFB/water CTAmetaFB/water and CTAparaFB/water systems in diluted concentrations. We presented a study of molecular dynamics simulation of the hydration of ortho-, meta-, para- Fluorobenzoate surfactants and its effect on the formation of micelles.The effect of hydrotropes organic counterions , 2- , 3- and 4- fluorobenzoic acid (2FB-, 3FB- and 4FB-, respectively), the shear thickening behavior of aqueous micellar solutions of rod like micelles thereof salts with cations of cetyltrimethylammonium (CTA2FB, CTA3FB and CTA4FB ) were studied.This work has contributed to the understanding of the synergy between the structure, dynamics and rheology of micellar in this family of copolymer
Stress-Temperature Effects on Transitions in PEO17PPO60PEO17 Triblock Copolymer Micellar Solutions by María Guadalupe Pérez-García( )

1 edition published in 2013 in English and held by 2 WorldCat member libraries worldwide

Influence des instabilités convectives sur l'etat de surface final des films polymère fabriqués par procédé de séchage by Noureddine Bassou( Book )

2 editions published in 2009 in French and held by 2 WorldCat member libraries worldwide

Cette thèse porte sur les instabilités de plissements de surface rencontrées dans le procédé de fabrication des films polymère par évaporation du solvant. Une étude détaillée des instabilités convectives se développant durant ce procédé est présenté. La caractérisation la morphologie 3D de l'état de surface des films secs a été effectuée pour différentes configurations de séchage. Finalement, le couplage de ces différentes études a permis la détermination des paramètres clefs contrôlant la morphologie des plissements de surface ainsi que l'établissement de modèles phénoménologiques
Maîtrise de la dynamique de la ligne triple pendant le séchage, vers des matériaux structurés à effet lotus by Benjamin Vuillemey( )

1 edition published in 2016 in French and held by 2 WorldCat member libraries worldwide

Solvent evaporation appears as an easy way to deposit a periodic film on any surface. Its resulting structure is directly linked to the particles contained on the suspension and its behaviour with its solid and liquid environment during drying step. The coffee ring effect is the most eloquent example, which is characterized by a preferential agglomeration of the particle in the drop periphery. Such process is difficult to assess: handling the air-liquid-substrate interface movement is a basic need to increase the technical power of that coating method.To investigate the contact line motion during drying, we focus on the meniscus, which comes from a liquid flow between a sealed container and a substrate. Observations of liquid flowing out such disposal show a cyclic movement. Such phenomenon can be compared to a breathing of the contact line. The present work is firstly dedicated to the characterization of that periodic movement. These learnings are then applied to polymer latexes to produce periodic films.Our characterization method is based on meniscus observation and force balance recording. The observed breathing can be tuned in frequency and amplitude, by acting both on physical properties of the solvents, and geometrical settings of the device. Surface tension play a key role in the movement, by acting on the meniscus shape. Geometrical settings appears to affect the evaporation process. On a global scale, the rate is constant but the disposal gap is directly linked to the cycle frequency.Eventually, our disposal is used to coat smooth surface with polymer latexes. The self-organization of particles during the drying process is tried to be controlled by the periodic motion of the contact line. The roughness of the obtained textured coating is expected to be tuned by a combined choice of disposal settings and specific solutions properties
Étude des propriétés thermodynamiques et dynamiques des polymères confinés en géométrie nanoparticules by Chourouk Mathlouthi( )

1 edition published in 2016 in French and held by 2 WorldCat member libraries worldwide

Contrôle de la formation de motifs conducteurs par jet d'encre : Maîtrise multi-échelle des transferts de matière dans des suspensions nanométriques by Vincent Faure( )

1 edition published in 2017 in French and held by 2 WorldCat member libraries worldwide

This thesis focuses on the understanding of the mechanisms involved in the inkjet printing of silver nanoparticles-based inks in order to optimize the manufacturing of thin (width <100 µm) conductive tracks with high and homogeneous performances. Inkjet printing can be divided into several phases: the ejection of picovolumetric droplets, the impact on the substrate, the spreading and the drying. The drying phase is a complex phase prone to particle migration phenomena such as coffee ring effect. This phenomenon, due to the capillary flow which implies a movement from the center to the edges of the drop, drives most of the suspended particles towards the edges of the printed patterns. The aim of this work is to describe precisely and understand the mechanisms which operate and lead to the transfer effects in order to limit or even eliminate them and guarantee the production of performing and homogenous fine conductive lines. To achieve this objective, three paths of investigation were developed: (i) a first axis deals with the study of the different phases of the droplet generation process. Parameters impacting the dried droplet morphology are identified and optimized with a focus on substrate temperature. Four geometrical indexes are designed to characterize quantitatively the dried droplet profile homogeneity. (ii) A second axis specifically studies the drying phase of picovolumetric droplet in order to understand the phenomena occurring during this phase. A modelling of droplet drying is set up in order to understand the forces influencing the matter transport. (iii) Finally, a last axis studies the print of thin conductive lines composed of several printed droplets partially superimposed. Correlations between line morphology, droplet morphology and electrical conductivity are established in order to produce optimized systems
Étude du comportement d'ADN en solution et aux interfaces et le rôle de la dynamique micellaire et la rhéologie dans la libération contrôlée de médicaments by Lourdes Mónica Bravo Anaya( )

1 edition published in 2015 in English and held by 2 WorldCat member libraries worldwide

Nowadays, the target for reaching a greater efficiency in DNA compaction processes, the innovation ofDNA sensors development and the study of changes in the interfacial properties generated between metalsurfaces and DNA molecules has become an area of great interest in bioengineering. This section of thethesis proposes the coupling of rheological, electrochemical and optical techniques to perform a detailedstudy of DNA molecules behavior in the bulk state of the solution and at the interface with two differentmetallic surfaces, as a function of parameters such as temperature, DNA concentration and electricpotential. Firstly, the rheological behavior of DNA/buffer solutions, as well as the evidence of the criticalconcentrations (C★ and Ce) is discussed from simple steady state and oscillatory dynamic shearexperiments. After studying DNA solutions properties, electrochemical and optical techniques are used toidentify structural changes in Au/DNA and Pt/DNA interfaces and to describe the arrangement of DNAchains in the electrochemical double-layer as a function of concentration and within each characteristicregime, i.e. dilute and semi-dilute regimes. The obtained response trough Electrochemical ImpedanceSpectroscospy (EIS), Modulation Interfacial of the Capacitance (MIC) and Surface Plasmon Resonance(SPR) techniques reflects an adsorption process of DNA molecules taking place onto the metal surfaces.Finally, by selecting DNA concentrations in the dilute regime, we studied the formation of chitosan-DNAnanoparticles with defined stoichiometry for gene transfer.The specific delivery of active ingredients, known as vectorization, has actually become a greatchallenge in therapeutic research. This process has been used to control the distribution of activeingredients such as proteins, genes for gene therapy and drugs, to a target by associating it with avector. Molecules for chemotherapy are frequently hydrophobic and require vectorization to betransported to the target cell. In this section of the thesis, we look up to understand the collectiveexchange dynamics (fusion and fission) between amphiphilic block copolymer micelles at the equilibriumand out of the equilibrium, and the exchange dynamics between these micelles (representing vectors)and the simplest model of cells (liposomes). We used a fluorescent technique with hydrophobic pyrenederivative to probe the fusion and fission of micelles at equilibrium. After characterizing amphiphilicblock copolymers structure and studying their dynamics in and out of equilibrium, we proposed a timescan fluorescence technique to quantify the collective vectorization dynamics between amphiphilic blockcopolymer micelles and liposomes. The effect of the variation of several parameters such as liposomeconcentration and a chitosan adsorption were investigated in order to control the vectorizationdynamics between these vectors and cells models
Utilisation des neutrons pour la protection des œuvres d'art by Amélie Castel( )

1 edition published in 2020 in English and held by 1 WorldCat member library worldwide

 
Audience Level
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Audience Level
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  General Special  
Audience level: 0.95 (from 0.93 for Stress-Tem ... to 0.97 for DEFORMATIO ...)

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