bluuebunny/crossref_metadata_2025 huggingface dataset:
Quelques usages de l'activité d'ingénierie de formation
Authors: Leclercq Gilles
Published: October 2010

Résumé Dans ce texte, l’auteur a souhaité répondre à la question suivante : quels sont les différents usages de cette activité qu’on nomme « ingénierie de formation » ? Les informateurs sont des étudiants qui exercent cette activité en même temps que le métier d’étudiant. Pour assurer la lisibilité de leur espace professionnel, ils utilisent un guide de lecture qui a été conçu en collaboration avec eux. Parmi les retombées, il en est une qui n’était pas prévue à l’origine. L’interprétation des données recueillies conduit à repérer différentes formes et différents usages de l’activité d’ingénierie de formation.
La dynamique des interactions tuteurs-stagiaires en situation de conseil pédagogique
Authors: Trohel Jean , Chaliès Sébastien , Saury Jacques
Published: October 2010

Résumé Cette étude analyse les interactions au sein de quatre dyades composées chacune d’un enseignant d’EPS (conseiller pédagogique) et d’un enseignant stagiaire, au cours d’entretiens de conseil post-leçons. Ces interactions sont étudiées en tant qu’actions collectives situées et en référence au cadre théorique du cours d’action. Trois sortes de matériaux ont été recueillis : enregistrements vidéo des leçons menées par le stagiaire ; enregistrements vidéo des entretiens post-leçons ; verbalisations lors d’autoconfrontations individuelles. Les résultats montrent qu’au cours de l’entretien, l’interaction entre le tuteur et le stagiaire s’organise selon des références identitaires multiples et fluctuantes. Ils permettent d’identifier des discordances dans la dynamique de l’interaction et certains dysfonctionnements dans la relation. La discussion met en évidence des paradoxes et des dilemmes chez les acteurs.
Des principes éthiques pour une philosophie de l'accompagnement
Authors: Beauvais Martine
Published: October 2010

Résumé Il se peut que l’engouement connu aujourd’hui pour l’accompagnement ne soit que le simple effet d’une mode. Mais il se peut aussi qu’il soit le reflet d’un véritable changement paradigmatique. Et dans ce cas, il paraît urgent d’entreprendre une réflexion d’ordre épistémologique et éthique susceptible d’aider les praticiens à mieux penser et agir leurs accompagnements singuliers. Ainsi, de l’émergence d’un possible postulat paradigmatique à la tentative de formulation de principes éthiques cet article se veut une modeste contribution à l’effort d’élucidation et de conceptualisation de la notion d’accompagnement.
Modalité d'interaction humaine dans la formation en ligne : son influence sur l'apprentissage
Authors: Nissen Elke
Published: October 2010

Résumé La présence de l’interaction humaine dans une formation en ligne s’est accrue avec l’évolution des technologies de la communication et fait partie aujourd’hui des composantes habituelles de ces formations. L’interaction sociale est vue comme un facteur d’apprentissage. Or, la question se pose de savoir quelle modalité d’interaction est la plus adaptée pour un type de tâche et pour un contexte donnés. À côté d’un tutorat qui paraît indispensable pour l’orientation des étudiants à distance, le groupe restreint apporte-t-il des bénéfices ? Les modèles théoriques généralement utilisés sont issus de l’enseignement présentiel et ne mettent pas en parallèle une situation d’interaction en groupe tutoré et une autre en individuel tutoré. Notre recherche empirique a ainsi pour objectif de voir laquelle des deux modalités d’interaction est le mieux adaptée dans une formation en langues à distance qui se situe dans une perspective actionnelle. Elle compare les deux modalités, et cela successivement sur deux plates-formes. Le groupe a tendance à progresser davantage que les individuels tutorés dans la qualité de ses rédactions durant la phase de formation. En revanche, en termes d’apprentissage, aucune différence significative entre les deux populations ne peut être observée. Les phénomènes observés restent stables d’une plate-forme à l’autre, faisant ainsi apparaître le groupe restreint tutoré, dans le contexte donné, comme un moyen performant pour produire, mais pas forcément pour apprendre.
Apprendre dans les collectifs solidaires. Le cas de l'éducation sociale des adultes en France à la fin du 19e siècle
Authors: Laot Françoise F.
Published: October 2010

Résumé Cet article propose une relecture éclairée par l’histoire de quelques notions actuellement explorées dans le champ de la recherche en formation, notamment celles d’ apprentissage informel et de compétences sociales . Quelques discours sur l’éducation des adultes publiés à la fin du 19 ème siècle en France, montrent en effet comment des idées proches étaient déjà présentes. Il est intéressant d’étudier comment on les nommait et comment on en reconnaissait l’intérêt. Les exemples sont tirés de textes portant sur l’« éducation sociale », écrits autour de 1900, période charnière où l’expression explose littéralement, portée notamment par deux figures : Léon Bourgeois (fondateur du Solidarisme) et Marc Sangnier (animateur du Sillon, mouvement de catholiques sociaux), ainsi que par les promoteurs laïcs des universités populaires. Nous y verrons comment, plutôt qu’à suivre un enseignement spécifique, les promoteurs de cette éducation sociale engagent les adultes à s’impliquer dans l’action, au sein de collectifs (cercles d’études, associations, coopératives, syndicats) afin de comprendre en profondeur ce qu’est la solidarité . Au-delà, le projet consiste à étudier le développement de l’éducation et de la formation des adultes en rapport avec celui de la Question sociale qui s’est imposée au milieu du 19 ème siècle, et le rôle qu’y joue la sociologie naissante.
La formation des enseignants aux méthodes d'apprentissage coopératif : perspectives internationales
Authors: Baudrit Alain
Published: October 2010

Résumé Ce texte se présente comme une revue de question de la littérature internationale, notamment anglo-saxonne, sur une forme d’activité collective (l’apprentissage coopératif) mise en lien avec la formation des enseignants (ici le développement professionnel). En quoi la première est-elle de nature à favoriser la seconde ? Quel intérêt présente-t-elle dans le sens du développement des habiletés et compétences professionnelles des enseignants ? Ce lien est-il évident ? Telles sont les principales questions posées. Sans compter que, dans cette affaire, le rôle des formateurs ou des enseignants rompus à la technique de l’apprentissage coopératif mérite également d’être pris en considération. Il y a certainement là des pistes à explorer pour les chercheurs de l’éducation en France, surtout pour ceux qui étudient l’introduction des cultures coopératives dans les établissements scolaires, tant au niveau des élèves que des enseignants 1 .
Rapport au savoir et mémoire professionnel de l'enseignant-stagiaire en lettres : trois études de cas à l'IUFM Midi-Pyrénées
Authors: Brossais Emmanuelle , Terrisse André
Published: October 2010

Résumé Dans le contexte de la formation des enseignants débutants à l’IUFM Midi-Pyrénées, nous nous intéressons à la façon dont les stagiaires s’approprient le savoir, à la façon dont ils vivent leur formation. Notre étude a pour objet d’analyser le sens que prend pour des professeurs-stagiaires le mémoire professionnel. Nous nous attachons aux différents types de rapports au savoir (Charlot, 1997) repérables dans ces mémoires. Nous présentons trois études de cas de professeurs-stagiaires en lettres selon trois dimensions du rapport au savoir : le rapport identitaire au savoir, le rapport épistémique au savoir et le rapport à l’écriture. Nos résultats permettent de repérer, sous d’apparentes similitudes, le caractère singulier du rapport au savoir qui se révèle dans le mémoire professionnel.
La recherche-intervention comme mode d'interrogation des pratiques
Authors: Merini Corinne , Ponté Pascale
Published: October 2010

Résumé Le développement de recherches ayant trait aux pratiques enseignantes et l’importance accordée au contexte dans la recherche en éducation légitiment pour une part la recherche-intervention, que nous employons à caractériser dans cet article. Après avoir situé l’émergence de la notion à partir d’une analyse socio-historique de la recherche-action, nous tentons de clarifier les relations de coopération qui s’instaurent entre recherche, formation et intervention à partir d’une analyse comparative secondaire de deux recherches inscrites dans cette dynamique. En tant que pratiques, recherche et intervention s’ancrent dans des systèmes d’action à la fois situés et orientés et qui règlent l’affrontement subjectif/objectif (Kohn, 1998) facilitant certaines phases de la démarche de recherche, demandant la plus grande vigilance sur d’autres points.
Formations ouvertes et autodirection de l'apprenant
Authors: Jézégou Annie
Published: October 2010

Résumé Cet article pose un premier jalon théorique et opérationnel de l’articulation entre l’ouverture en formation et l’autodirection de l’apprenant. Il fonde tout d’abord la définition selon laquelle une formation est ouverte si elle ouvre des libertés de choix à l’apprenant, au regard des différentes composantes du dispositif pédagogique. Puis, il propose une modélisation triadique permettant d’articuler l’ouverture du dispositif et deux dimensions sociocognitives de l’autodirection : la perception d’ouverture - ou de libertés de choix - des apprenants face au dispositif et leurs comportements autorégulés de gestion de ce dispositif. Enfin, il montre, en s’appuyant sur les résultats d’une étude empirique, que la perception des apprenants au regard de l’ouverture joue ici un rôle médiateur dans l’influence du dispositif sur leurs comportements autorégulés.
Les effets de l'usage des technologies d'information et de communication en formation d'enseignants, sur la construction des postures professionnelles
Authors: Lameul Geneviève
Published: October 2010

Résumé Cet article rend compte de notre thèse relative aux effets de la médiatisation de la relation pédagogique sur la construction des postures professionnelles enseignantes. Après avoir précisé la problématique et la démarche méthodologique employée, l’article se centre sur les principaux résultats obtenus : démystification du pouvoir des TIC sur l’apprentissage ; mise en évidence de leur dimension d’« analyseur » de questions pédagogiques de fond ; révélation de l’existence de jeux de tensions propices à l’évolution des postures ; illustration de toute l’importance d’une prise en compte des facteurs personnels (cognitifs, conatifs, émotionnels et biologiques) lors de la conception des dispositifs de formation. Ce texte se donne un double objectif : faire partager à la communauté scientifique les savoirs émanant de ce travail en vue de susciter des collaborations pour poursuivre la recherche, et interpeller les praticiens par rapport aux pratiques d’ingénierie à développer en vue de créer les meilleures conditions possibles de l’apprenance.
Parcours et identités des enseignants de l'enseignement primaire au Portugal : de la formation à la réalité
Authors: Ferreira Elisabete , Lopes Amélia , Machado Gabriela , Rocha Rosália , Sá Maria José , Silva Manuel António
Published: October 2010

Résumé Afin d’étudier le rôle joué par la formation initiale et par la pratique professionnelle dans l’identité actuelle de professeurs portugais de l’enseignement primaire, nous présentons et commentons l’analyse de 40 interviews biographiques faites à des professeurs formés à 4 périodes différentes au cours des 30 dernières années. Les résultats montrent qu’à chaque période correspond une identité professionnelle de base différente, mais aussi qu’au cours du parcours professionnel, les identités deviennent semblables et, en général, moins exigeantes. En mettant en évidence le rôle des contextes de travail dans le façonnage d’identités moins exigeantes, ces résultats soulignent l’importance d’investir dans l’amélioration de la qualité de ces contextes.
L'influence d'un stage de formation Continue en EPS : un autre regard sur les jeux traditionnels
Authors: Dugas Éric
Published: October 2010

Résumé En éducation physique et sportive, la diversité des dispositifs et des modalités de formation continue témoigne de la complexité des attentes et des besoins des enseignants. Malgré ce foisonnement, les occasions sont limitées d’initier les enseignants du second degré à la mise en œuvre didactique et pédagogique de jeux traditionnels collectifs, le plus souvent considérés comme de simples prémices à l’enseignement des sports collectifs. Nous avons saisi l’opportunité d’encadrer une de ces rares formations offertes en région parisienne. À l’aide principalement de la technique de la comparaison par paires (procédure Condorcet) - test passé avant et après le stage - nous avons constaté une évolution des représentations des enseignants stagiaires: les jeux traditionnels semblent révéler des valeurs éducatives qui mériteraient mieux qu’un simple détour.
La construction de la langue écrite par l'adulte apprenant : l'exemple de la copie d'écrit
Authors: Balas Bernard
Published: October 2010

Résumé L’objectif de la recherche est de voir comment l’adulte construit sa représentation de la langue écrite. La copie d’écrit est utilisée comme un indicateur et un outil d’évaluation de la théorie de l’écrit que l’apprenant élabore au cours de son apprentissage. Il se dégage que le sujet passe par cinq phases ou périodes de démarches successives pour élaborer sa représentation de la langue écrite : la démarche visuo-graphique par laquelle il considère l’écrit comme un tout visuel ; la démarche des relations écrit-oral où il utilise une représentation visuelle pour élaborer une démarche orale et comprendre ainsi que l’écrit, c’est du langage ; la démarche des relations oral-écrit où son intention est de construire des unités prononçables ; la démarche de la construction du mot où il formalise sa représentation du mot comme unité lexicale et s’en sert comme point d’appui pour construire des groupes de mots ; la démarche sémantique et syntaxique où il construit des unités de sens en fonction de leur position dans la phrase. Il s’oriente alors vers une démarche textuelle.
Accompagner les candidats à la VAE. Le mythe de la juste distance
Authors: Crognier Philippe
Published: October 2010

Résumé Cet article explore les pratiques d’accompagnement des candidats inscrits en Vae pour l’obtention du diplôme d’éducateur spécialisé. Il montre que la frontière entre accompagnement et formation est ténue et que les pratiques d’accompagnement nécessitent le repositionnement permanent des professionnels chargés de guider les candidats dans la composition de leur dossier.
Le sentiment d'efficacité personnelle dans l'apprentissage et la formation : quel rôle joue-t-il ? D'où vient-il ? Comment intervenir ?
Authors: Galand Benoît , Vanlede Marie
Published: October 2010

Résumé Cet article passe en revue les recherches empiriques concernant les croyances d’efficacité personnelle dans le domaine de l’enseignement et de la formation. Trois questions principales sont abordées : Que sait-on du rôle du sentiment d’efficacité dans l’apprentissage ? Quelles sont les sources du sentiment d’efficacité dans le domaine de l’apprentissage formel ? Quelles sont les interventions éducatives possibles afin d’accroître le sentiment d’efficacité personnelle des apprenants ? Les résultats passés en revue indiquent que les croyances d’efficacité ont des effets non négligeables sur l’engagement, les performances et la trajectoire de formation des apprenants. D’autres résultats permettent de mieux cerner les sources d’information qui influencent ces croyances d’efficacité. Nombre de recherches présentées offrent des pistes d’action pour des interventions pédagogiques. Globalement, les études présentées démontrent qu’il est possible de soutenir le développement des compétences et du sentiment d’efficacité des apprenants, même quand ceux-ci ont un niveau initial de compétence très bas.
Contribution à l'étude des liens entre engagement en formation et rapport au travail
Authors: Crochard Magali
Published: October 2010

Résumé L’objectif de cet article est de contribuer à une meilleure compréhension de l’engagement en formation et de ses enjeux identitaires. Cette recherche, de nature exploratoire, est fondée sur une étude de cas longitudinale, celle d’un groupe sortant de formation professionnelle universitaire. Une revue de la littérature sur la dynamique de constructions identitaires et des représentations sociales révèle l’intérêt d’une mise en perspective du sentiment d’autodétermination comme variable d’interprétation ; par ailleurs, les données collectées font état de sentiments spécifiques, voire de « représentations ambivalentes » de l’objet travail, et du manque d’échange social comme élément pouvant conduire à ce que nous appelons une « impasse » identitaire.
Sol-Gel Synthesis Assisted by Supercritical CO2 - A Flexible Process for Ceramic Powder and Membrane Preparation
Authors: Hertz Audrey , Durand Véronique , Sarrade Stéphane , Guizard Christian , Julbe Anne , Ruiz Jean-Christophe , Charton Frédéric
Published: October 2010

The increasing interest in supercritical fluids for synthesizing inorganic materials
stimulated the development of new processes for production of nanophased powders/layers with
controlled characteristics. Original processes based on sol-gel synthesis assisted by supercritical
CO2 have been developed. Unusual powder structures/morphologies have been evidenced and cosolvent
characteristics have been proved to influence powder specific surface area and crystallite
sizes. The development of a new semi-continuous process also enabled to tailor powder
morphology by controlling hydrodynamic parameters (injection speed and stirring rate).
Especially, yttria-stabilized zirconia prepared with this method are composed of 5-7 nm
crystallites aggregated in spherical nanoparticles (<100nm) and yielding particularly high specific
surface areas (up to 250 m2/g). These YSZ powders can be compacted/deposited and sintered to
prepare nanosized dense membranes for ionic conduction. Finally, SC-CO2 sol-gel processes can
also be adapted to directly prepare gas separation membranes. In particular, an innovative process
has been developed to coat tubular porous ceramic substrates with porous silica-based layer.
Enhanced Densification and Grain-Size Refinement in Cation-Doped Tetragonal Zirconia
Authors: Hiraga Keijiro , Yoshida Hidehiro , Morita Koji , Kim Byung Nam
Published: October 2010

In tetragonal zirconia, possibility is investigated of densification with finer grain sizes under the combination of doping and sintering in air. The materials used are CIP'ed compacts of 3-mol%-yttria-stabilized tetragonal zirconia (3Y-TZP) doped with a small amount of cations. For a given sintering temperature and initial density of the compacts, while the doped cations enhances densification in the latest stage of sintering, the effect is different in grain growth during densification: a doped cation tended to enhance grain growth, whereas the other cations tended to suppress grain growth. As a result, the doping of the latter cations brings about a grain size finer than that of the undoped 3Y-TZP for a given relative density.
Ceramic Matrix Composites in the Alumina/YAG System
Authors: Lach Radek , Haberko Krzysztof
Published: October 2010

Preparation technique of the particulate composite materials in the alumina/YAG system
were studied. Within alumina particle suspension yttria precursor was precipitated with ammonium
carbonate. Drying and calcinationa at 600oC resulted in the mixture of alumina and yttria particles.
The latter being much finer than alumina particles. This mixture was additionally homogenized by
short attrition milling in an aqueous suspension of pH which level was selected on the basis of zeta
() potential measurements. It was found that acidic conditions (realized with HNO3) result in hard
agglomerates. Such powders showed poor sintering ability and not homogenous second phase
particles distribution. Much better properties were observed in case of powders homogenized under
basic condition. They give dense materials composed of YAG inclusions of sizes several times
smaller than shown by alumina grains and evenly distributed within the matrix. YAG particles
result from the reaction of Y2O3 with Al2O3 during heat treatment. Some compositions show
fracture toughness essentially higher than observed in pure alumina polycrystals.
La1.97Sr0.03Zr2O7 Pyrochlore Powder for Advanced Energy Application
Authors: Chen Yan , Orlovskaya Nina , Miller Nicholas , Abernathy Harry , Haynes Daniel , Tucker David , Gemmen Randall
Published: October 2010

Materials with A2B2O7 (pyrochlore) structure have received a significant attention for their applications as new protonic conductors and materials used in electronic devices. One of the unique synthesis routes for La2Zr2O7 (pyrochlore) powders is the glycine-nitrate combustion method, which shows superior properties of the synthesized powder by using glycine as a complexing agent. The Sr doped La2Zr2O7 powders in pure pyrochlore structure were produced using this approach. Selected characteristics of the synthesized powders, such as crystal structure, lattice parameters, crystallite size, the vibrational properties, the morphology of the particles, along with the specific surface area and particle size have been investigated. The dependence of some properties on annealing temperatures of the powders has been studied.
Flame Synthesis of Ceramic Particles
Authors: Takao Yasumasa
Published: October 2010

We introduce a case study of “high sphericity” and “high uniformity” generated through flame synthesis. Recently, cosmetics need to solve 1) UV-protective effect, 2) transparence, and 3) smooth-textured touch. However, the best recipe and usable evaluation methods are not established. This research is a result combined with a theoretical approach of flame formation process, and a strategic regional alliance of the “AIST” grant venture. A new manufacturing and evaluation method has been commercialized in the forms of a highly original cosmetics and a new evaluation device.
Effects of Firing Temperature and Time on the Luminescency of Phosphors in Strontium Aluminate System Co-Doped by Eu2O3 and Dy2O3 and Prepared by Solid State Reaction Processing
Authors: Yesilay Kaya Selvin , Karasu Bekir , Kaya Guray , Karacaoğlu Erkul
Published: October 2010

In the current study long afterglow phosphors in strontium aluminate system doped with Eu2+ and Dy3+ were synthesized at different firing temperatures for various time. Photoluminescency and crystallisation during sintering under reducing atmosphere were examined as functions of sintering time and temparature. XRD was employed to characterize the crystal phases of phosphors. Scanning electron microscopy (SEM) investigations were carried out to understand surface morphology and to confirm the XRD results. The optical properties of the phosphors were investigated by a phosphorescence spectrophotometer. The changes in emission and excitation spectrum were discussed accounting firing time and temperature.
Clay Aerogel Composite Materials
Authors: Schiraldi David A. , Gawryla Matthew D. , Alhassan Saeed
Published: October 2010

A simple, inexpensive, and environmentally-friendly process for converting mixtures of clays
and polymers has been developed. Polymer and clay are combined in water, and the mixtures are
freeze dried to produce materials which have bulk densities typically in the range of 0.03 – 0.15
g/cm3. These low density polymer/clay aerogel materials possess good mechanical properties
similar to those of traditional polymer foams, can be reinforced with fibers, modified with
nanoparticles, biomineralized, or converted into porous ceramics.
Synthesis and Characterization of Mesoporous Hydroxyapatite
Authors: Lew Kien Seng , Othman Radzali , Yeoh Fei Yee
Published: October 2010

Among the porous media, hydroxyapatite (HA) possesses good biocompatibility and bioactivity properties with respect to bone cells and tissues, due to its similarity with the hard tissues of the body. In this study, mesoporous HA was synthesized using a soft-templating technique via a self-assembly between HA and cationic surfactant decyltrimethylammonium bromide (C10TAB), which is analogous to the synthesis of mesoporous silica MCM-41. This co-precipitation method involved formation of hexagonal-phase micelle template by the surfactant and the precipitation of HA surrounding the micelle. After ageing, calcination was carried out to remove the templates, revealing the pores as well as to produce more crystalline and more stable HA structure. This study showed that instead of hexadecyltrimethylammonium bromide (C16TAB) which was conventionally used, C10TAB could also be used to synthesize single-phase mesoporous HA with pore size ca. 3 nm. Ageing temperature of 120 °C, for 24 hours was found sufficient for the formation of mesoporous HA. The adsorption properties of mesoporous HA was able to be improved by increasing the water content of C10TAB-phosphate solution and by constant pH adjustment during the mixing of solutions.
Processing of Municipal Solid Waste (MSW) Fly Ash into an Environmentally Stable and Safe Material
Authors: Isac Mihaeila , Ghouleh Zaid , Guthrie Roderick I.L.
Published: October 2010

The purpose of this research was to design a processing route for the conversion of hazardous Municipal Solid Waste (MSW) fly ash into a glass-ceramic material, stable and safe for further industrial, structural, or ornamental applications. The process firstly consists in the transformation of a hazardous MDW fly ash into a vitrous material. Thermal analyses information was used to design the controlled heat treatment that further transformed this vitrous material into an environmentally safe composite. The final product obtained was a glass-ceramic material with randomly oriented crystals embedded in its residual amorphous matrix. The crystalline phases were identified as Nepheline and Diopside. CLSM (Confocal Laser Scanning Microscopy) was used for real-time in-situ observation of the microstructure under simulated heat treatment conditions. 
Microwave Activated Combustion Synthesis and Compaction in Separate E and H Fields: Numerical Simulation and Experimental Results
Authors: Rosa Roberto , Veronesi Paolo , Leonelli Cristina , Bonamartini Corradi Anna , Ferraris Monica , Casalegno Valentina , Salvo Milena , Han Shao Hua
Published: October 2010

Microwaves (MW) at the ISM frequency of 2.45 GHz have been used to ignite the
Combustion Synthesis (CS) of pressed ceramic and metallic powders mixtures, using a single-mode
applicator (TE103). This experimental apparatus allows to study the separate effect of prevalent
electric or magnetic field on the selective heating of the reactive powders compacts, while
transferring energy and not heat before and after CS.
Microwave activated combustion syntheses (MACS) of TiC-40 wt%Fe and FeAl intermetallic
compounds were performed in the two different field configurations (maximum of the electric field
(E) and maximum of magnetic field (H)) in order to investigate any possible difference in the reaction
mechanism and in the final microstructure of the products.
MACS in the maximum of E has also been applied to high temperature materials joining, with the
application of a moderate pressure during the irradiation with electromagnetic waves, to promote
adhesion and to reduce the newly formed compounds porosity.
Production of Zirconium Diboride Powder by Self Propagating High Temperature Synthesis
Authors: Akkas Burcu , Alkan Murat , Derin Bora , Onüralp Yücel
Published: October 2010

In this study, the self-propagating high-temperature synthesis (SHS) and following acid leaching techniques were carried out to produce zirconium diboride (ZrB2) powder. In the SHS experiments, technical grade ZrO2 powder, and different amounts of B2O3 and Mg powders were used. The SHS products were obtained in the form of black, spongy solid. In the leaching step, the effect of different acid concentrations on selective leaching was investigated by using optimum SHS product to eliminate the impurities such as MgO, Mg3B2O6 and Mg2B2O5. The products obtained were characterized by using XRD, ICP and SEM techniques.
Catalytic Properties of the SHS Products - Review
Authors: Xanthopoulou Galina
Published: October 2010

The Self-Propagating High-Temperature Synthesis (SHS) method has been used to produce a new class of active catalyst materials based on metals, metal oxides and spinels for various applications. The method is characterized by very fast processing times (of the order of minutes), relatively low preheating temperatures and very high reaction temperatures produced as a result of carefully designed exothermic reactions. A large range of materials have been produced and characterized by a variety of physico-chemical and mechanical tests. This review devoted to Catalytic properties of SHS products. A number of catalytically active materials all over the world have been identified which offer promise for applications ranging from oxidation of CO and hydrocarbons to reduction of NOx, methane dehydrogenation and other.
Synthesis of Monodispersed Plate-Like CeO2 Particles by Precipitation Process in Sodium Hydrogen Carbonate Solution
Authors: Yin Shu , Minamidate Yoshihiro , Sato Tsugio
Published: October 2010

Monodispersed plate-like CeO2 particles were successfully synthesized by a mild solution process followed by calcination in air at 400oC. During the solution processing, monodispersed orthorhombic single-crystal of plate-like Ce2(CO3)3.8H2O was obtained by using Ce(NO3)3.6H2O as cerium source, and NaHCO3 aqueous solution as precipitation reagent and carbon source. The concentration of NaHCO3 solution affects the morphologies and particle size of the cerium carbonate compounds. High concentration of NaHCO3 led to a decrease in the particle size of Ce2(CO3)3.8H2O effectively. The CeO2 particles synthesized by the decomposition of carbonate precursors possessed similar morphologies and slightly smaller particle size. The plate-like ceria particles possessed good UV-shielding properties and low oxidation catalytic activities, indicating the potential application as cosmetics materials
Development of Functionally Graded Coating Based Plasma Facing Materials for Fusion Reactor
Authors: Ge Chang Chun , Guo Shuang Quan , Feng Yun Biao , Zhou Zhang Jian , Du Juan , Zhou Hai Bin , Wang Chun
Published: October 2010

Different coating technologies, such as plasma spray (PS), physical vapor
deposition (PVD) and chemical vapor deposition (CVD), which can fabricate the
PFM and join it to heat sink materials simultaneously, were applied for the fabrication
of plasma facing materials (PFM) in fusion reactor. In the Institute of Nuclear
Materials, University of Science and Technology Beijing (USTB), the concept of
functionally graded materials (FGM) was adopted to fabricate coatings for effectively
alleviating the thermal stress generated between coatings and the substrate materials
under high heat flux loading (5~20 MW/m2). In the last several years, functionally
graded coatings, including B4C/Cu, W/Cu and Mo/Cu systems were successfully
fabricated by atmospheric plasma spray (APS). Characterization of coatings was
performed in order to assess microstructure, mechanical properties and high heat flux
properties of the FGM coatings. Furthermore, a high thick tungsten coating with 4
mm on copper – chromium - zirconium (Cu, Cr, Zr) alloy substrates was fabricated by
APS. The porosity of the coating is less than 2% while mean tensile strength of the
coating is about 7 MPa. However, the content of oxygen in the coating is about 6 wt%
by energy dispersive spectrum (EDS) analysis, thus further optimization is necessary.
Relationship Between Microstructure and Hardness of ZrN/TiN Multi-Layers with Various Bilayer Thicknesses
Authors: Aoi Yoshifumi , Furuhata Satoru , Nakano Hiromi
Published: October 2010

ZrN/TiN multi-layers were synthesized by ion beam sputtering technique. Microstructure
and mechanical property of the ZrN/TiN multi-layers were characterized and the relationships
between microstructure and hardness of the ZrN/TiN multi-layers with various bilayer thicknesses
and thickness ratios were investigated. The microstructure of multi-layers have been investigated
using transmission electron microscope (TEM) and X-ray diffraction (XRD).
Mechanical Properties of Si3N4-SiC Composites Sintered by HPHT Method
Authors: Klimczyk Piotr
Published: October 2010

Three types: micro-, submicro- and nano-structured Si3N4-SiC composites have been
obtained by High Pressure-High Temperature (HPHT) sintering. Density, Young modulus, hardness
and fracture toughness have been measured. Composites obtained from sub-micron powders are
characterized by better mechanical properties than composites obtained from nanopowders.
Tailored Silica Based Xerogels and Aerogels for Insulation in Space Environments
Authors: Durães Luisa , Ochoa Marta , Portugal António , Duarte Nelson , Dias João Paulo , Rocha Nuno , Hernandez Jessica
Published: October 2010

In this work, the sol-gel technology is used to produce silica based xerogels and aerogels
suitable for insulation applications in Space. The properties of the obtained materials are tailored
varying the precursor – Methyltrimethoxysilane (MTMS) or Methyltriethoxysilane (MTES), and the
solvent – methanol or ethanol. A two-step acid-base catalyzed synthesis is used, being the obtained
gels dried at atmospheric pressure, in the case of xerogels, and in supercritical conditions, for
aerogels. Density and thermal conductivity must be made as low as possible for the sought
application and only highly porous materials can fulfill this requirement. The obtained xerogels and
aerogels, either with MTMS or MTES, show very promising properties for thermal insulation in
Space, when methanol is used as solvent. The more suitable materials are obtained with MTMS and
exhibit very low density (80-100 kg/m3), very high surface area (~ 400 m2/g) and small pore size
(~ 30-40 Å). They also show moderate flexibility and a remarkable hydrophobic character (~ 150º).
In Situ TEM Observation of Crystallization Process for LiNbO3 and NaNbO3
Authors: Nakano Hiromi , Suyama Yoko
Published: October 2010

Fabrication of advanced electronic components requires high-quality powders. In this work, nano-powders of Li or Na niobates are synthesized from (Li or Na)-Nb ethoxide by a sol-crystal method. A single crystal of (Li or Na)-Nb ethoxide is decomposed to an amorphous matrix below 473 K. Next, small crystals are grown by heating at the appropriate temperature for each specimen. The sol-crystal method provides homogeneous quality and fine grains by heating at lower temperature. Structural analysis of the powders is performed by a transmission electron microscope (TEM) and X-ray diffraction. As a result, LiNbO3 turns to dense-powders, but NaNbO3 forms nano-porous powders. In order to understand this difference, we try to observe in-situ the crystallization and grain growth processes by high-temperature TEM. We successfully observe in-situ this processing and discuss the structural change and formation mechanism of LiNbO3, comparing these features with those of NaNbO3.
Corrosion of Single Crystal Cordierite by Model Diesel Particulate Filter Ashes: Mechanisms and Orientation Dependence
Authors: Maier Nicolas , Nickel Klaus G. , Engel Christine , Mattern Andreas
Published: October 2010

Cordierite Mg2Al4Si5O18 is a material for diesel particulate filters (DPF) with high potential. Its resistance to a simplified model ash has been tested on single crystals at temperatures up to 1050°C, which are realistic for use under ‘worst case’ conditions. A mixture of Ca, Mg and Zn phosphates, which are typical main constituents of many DPF ashes, was used as model ash. Single crystals were examined in order to investigate the orientation dependence of attack due to the strongly anisotropic nature of the Cordierite crystal lattice. Strong corrosion by the ash occurs at 1050 °C, connected to excessive ash melting. The molten ash attacks Cordierite by fast dissolution of the substrate with melt (super)saturation within minutes. Anisotropy of the dissolution process could not be detected. The initial kinetics are dominated by saturation effects, which slow down corrosion. The saturated melt attacks Cordierite by reaction processes leading to the formation of new crystalline phases. This process is much slower than the initial dissolution process but may significantly contribute to the destruction of Cordierite substrates if large contact areas between ash melt and Cordierite exist.
Interfacial Microstructure and Properties of SiC / SiC Joint Brazed with Ag-Cu-Ti Alloys
Authors: Ghazi Daryani Amir Hossein , Nemati A. , Kokabi A.H.
Published: October 2010

SiC Ceramic was joined to itself using active brazing Alloys, like Ti in shape of sheet
filler of Ag-cu and Ti-6AI-4V. This operation is occurred in an inert gas furnace.Interfacial
microstructure studied with Scanning electron microscopy and X-Ray diffraction. Variation of
Electrical Specific Resistance measured by 4 pin astute multimeter and strength of these joint
was measured by fracture shear loading. This Joint is happened at 900c and upper temperature
with 90 minutes and upper time. Electrical specific Resistance goes upper with joint in low
temperature & time but this variation is very little. The microstructure showed an excellent
bonding at the interfaces. The data showed also that the joining of the SiC decreases with
increasing temperature and time.
Tribological Performances of Polymer-Based Coating Materials Designed for Compressor Applications
Authors: Yeo Seung Min , Escobar Nunez Emerson , Polycarpou Andreas A.
Published: October 2010

With increasing importance of advanced coating materials for use in interacting parts of
air-conditioning compressors, several commercially available polymer-based coatings (PTFE/
Pyrrolidone-1, 2, PTFE/MoS2-1, 2, Fluorocarbon, PEEK/PTFE and PEEK/Ceramic coatings) were
tribologically evaluated. Friction and wear behavior of these coatings, deposited on gray cast iron
were in-situ measured using a specialized pin-on-disk tribometer. The experiments were performed
under compressor specific conditions, namely under oscillatory motion simulating piston-type
compressor and unidirectional motion simulating swash plate-type compressor operation. Also, the
tribological properties of newly developed ATSP-based coatings deposited on aluminum substrates
were evaluated under ball-on-disk, unidirectional sliding experiments. Polymer-based coatings
exhibited excellent frictional properties, while their wear resistance was also acceptable, even though
lower compared to hard coatings. However, the wear debris generated at the interface acted as a
third-body solid lubricant with a beneficial role in their overall performance. ATSP coatings blended
with fluoroadditives showed superior frictional behavior than pure ATSP coatings, and their wear
rate was extremely low compared to commercially available PTFE-based coatings.
Advanced Evaluation Methods of Residual Stress in Bioceramics Wear Surfaces
Authors: Pezzotti Giuseppe
Published: October 2010

Photo- and electro-stimulated probes have been employed for quantitatively evaluating
highly graded residual stress fields generated at the surface of alumina hip joints. Optical
calibrations revealed large differences in probe size, which strongly affected the detected magnitude
of residual stress. A comparison between the responses of Raman and fluorescence probes in
polycrystalline alumina showed that the depth of those probes spread to an extent in the order of the
tens of microns even with using a confocal probe configuration. On the other hand, the
electro-stimulated luminescence emitted by oxygen vacancy sites (F+ center) in the alumina lattice
represented a suitable choice for confining to a shallow volume the stress probe. The electron probe
enabled confining the measurement depth to the order of the tens of nanometers. Maps of surface
residual stress were collected on both main-wear and non-wear zones of an alumina femoral head.
A comparison among stress maps taken at exactly the same location, but employing different
probes, clarified the averaging probe effects on surface stress magnitude.
Mechanical Properties of Silicon Nitride Using RUS & C-Sphere Methodology
Authors: Hadfield Mark , Wang Wei , Wereszczak Andrew
Published: October 2010

Silicon nitride is a type of engineering ceramic which has been used in ball bearing and other rolling contact applications owing to its good fatigue life, high temperature strength and tribological performance. In this paper, the mechanical properties of Hot Isostatically Pressed (HIPed) and Sintered and Reaction Bonded Silion Nitride (SRBSN) have been studied. The elastic modulus and poisson’s ratio of three types of commerical grade HIPed silicon nitride, and ground SRBSN with three surface condidtions were measured using a Resonance Ultrasound Spectroscopy (RUS). The RUS measurement reveals the variation of elastic properties across different types of HIPed silicon nitride specimens. The surface strength of silicon nitride are studied using a C-sphere specimen, and the results show that SRBSN with three different surface finishing conditions show varied surface strength. The RUS and C-sphere techniques can potentially be used to sample the quality and consistency of ball bearing elements.
In Situ HRTEM Observations of Spreading Reactive Molten Alloy on Ceramic Substrates
Authors: Iwamoto Chihiro , Tanaka Shunichiro
Published: October 2010

In-situ HRTEM technique was applied to various substrates and the reaction processes
between substrates and molten alloy were compared. Substrates used were SiC, Si3N4, Si wafers, an
amorphous carbon film, and a carbon nanotube. Ti-containing Ag-Cu eutectic alloy foil was placed
on the substrate and the combined specimen mounted on the heating holder of an HRTEM and
heated in the microscope to melt the alloy foil. In the case of SiC, Si3N4, carbon materials, the
molten alloy spreading on the substrates were observed after melting of the alloy. SiC polar plane
nano-steps appeared with the SiC dissociation by the molten alloy. On the surface of the carbon
nanotube, thin film precursor spreading was observed. In contrast, Si reaction with the molten alloy
produced big holes at the contacted area and molten alloy spreading was not observed.
Processing and Thermal Properties of Cu-AlN Composites
Authors: Chmielewski Marcin , Pietrzak Katarzyna , Kaliński Dariusz , Strojny Agata
Published: October 2010

Heat transfer by conduction is involved in the use of heat sinks dissipitating heat from
electronic devices. Effective transfer of heat requires using materials of high thermal conductivity.
In addition, it requires appropriate values of thermal expansion, matched to the semiconductor
materials, high purity of materials used and good contact between bonded elements across which
heat transfer occurs. The conventional materials are not able to fulfil still raising and complex
requirements. The solutions of this problem could be using the composites materials, where the
combinations of different properties is possible to use. This study presents the technological tests
and the analysis of correlation between processing parameters and the properties of copperaluminium
nitride composites. Composite materials were obtained by mixing in planetary ball mill
and then densified using the sintering under pressure or hot pressing method. The microstructure of
obtained composite materials using optical microscopy and scanning electron microscopy were
analyzed. Coefficient of thermal expansion (CTE) and thermal conductivity (TC) were investigated
depending on the process conditions.
Development of Ultrasonic Optical Fiber Hydrogen Sensor
Authors: Yoo Jung Cheol , Kee Chang Doo , Oh Il Kwon
Published: October 2010

In this study, an ultrasonic optical fiber hydrogen sensor was newly developed for monitoring and detecting hydrogen leakages. Previously, we developed a pulse-echo sensor system for health monitoring system. Ultrasonic wave, generated from a piezoelectric actuator, is guided and propagated through the optical fiber and subsequently sensed by a piezoelectric sensor in the pulse-echo sensor system. For the detection of hydrogen, the optical fiber was coated with palladium particles, which expanded on exposure to hydrogen. Palladium was used, because it adsorbs hydrogen gas and swell slightly to form palladium hydride with exposure to hydrogen. The change in palladium dimensions affects the wave propagation impedance of optical fiber for detecting the hydrogen gas, and this method has been applied to the pulse-echo sensor systems. Our results showed that the ultrasonic-optical fiber hydrogen sensor can be successfully employed for hydrogen detecting system.
Determination of Lead Traces by Stripping Voltammetry Using Ti(N,C) Working Electrodes
Authors: Ziemnicka Marta , Baś Bogusław , Jeż Mateusz , Stobierski Ludosław
Published: October 2010

Electrochemical stripping techniques still attract considerable attention for trace metal analysis and for measuring
several important organic compounds, due to their unique capabilities of pre-concentrating the analytes at the electrode
surface and associated favourable low limits of detection. In this work it is reported for the first time that the
Ti(N0,1C0,9), Ti(N0,4C0,6) and Ti(N0,5C0,5) working disc electrodes, a „mercury-free” sensors, offers surprisingly good
analytical performance and some valuable properties.
The analytical applicability of the Ti(N,C) electrode was confirmed in determination of lead(II) traces in synthetic
solutions both with and without surfactants, in certified reference material and in natural water samples. The effects of
dissolved oxygen, acids, anions and metal ions were investigated for the Ti(N,C) electrode.
Newly prepared and not activated electrode usually cannot be polarized. Therefore, to use the electrode as a
voltammetric sensor, its electrochemical activation is required. Composition of conditioning electrolyte and procedures
of the electrodes activation were optimized.
The fabrication and the response performance of the investigated electrodes were described in the paper. The
voltammetric data were associated with the structural characterization of the electrode surface using scanning electron
microscopy (SEM) and transmition electron microscopy (TEM).
Catalyst Supports for Energy Conversion Processes
Authors: Fierro Jose L.G. , Pawelec Barbara
Published: October 2010

This contribution aims to provide a general overview of the potential of ceramic
materials in several areas related to energy production and storage. Ceramic materials
for both low and high temperature fuel cells are examined in some detail. Engineered,
porous, ceramic support loaded with noble metals are particularly suited to address the
material limitations encountered with wash-coated, metal-based, catalyst supports.
These materials demonstrated high-performance and resistance under severe operation
conditions. Metal oxides and carbides present high stability in a fuel cell environment
and acceptable electrical conductivity, but most of them possess a low specific area. In
addition, H2 production by water splitting on ceramic oxides of the type ferrites, YSZ
and other supported systems will be examined. Finally, a few aspects of the new
nanoscale ceramics for batteries of higher storage capacity and storage capacitors will
also be presented.