Notre étude porte sur les pierres à aiguiser, pierres à affûter, polissoirs et autres outils de l’abrasion découverts dans des sites égéens de l’Âge du Bronze. Durant cette période, les ressources lithiques naturelles égéennes prélevées étaient transformées et employées lors des actions d’abrasion, d’aiguisage, d’affûtage, de polissage. Une connaissance empirique du comportement des roches durant l’utilisation a guidé la sélection des supports afin d’optimiser l’efficacité de l’outillage lors des différentes opérations. Une analyse des provenances nous éclaire sur les modes d’acquisition et de circulation des matériaux ; et une étude complémentaire des propriétés mécaniques des roches nous renseigne sur les paramètres qui ont guidé le choix des matériaux. Les outils diffèrent de par leur matière première mais aussi de par leur morphologie, granulométrie et leurs traces d’usage. Cette recherche propose la mise en place d’une nouvelle analyse des traces, permettant de distinguer les stigmates d’usage et les usures. La méthodologie s’appuie sur des analyses menées en laboratoire (analyses pétrographiques, tribologiques), combinées à des observations sur des outils à différentes échelles. Une fois la fonction des outils identifiée, nous avons considéré les contextes de production et d’utilisation. Enfin, des études ethnographiques et la consultation d’outils archéologiques menées tout au long de nos recherches, nous ont permis de reconstituer les activités, les actions et les gestes liés à la fabrication et à l’utilisation des outils. / This research aims at investigating the supplying strategies of raw materials selected for the implementation of lithic tools in the Aegean sea during the Bronze Age. Furthermore, it addresses the possible exchange networks responsible for the wider distribution of abrasive rocks. Particularly, all steps of the operational process (chaîne opératoire) were investigated from the extraction of raw materials to the use of the stone tools. These research objectives were addressed through an interdiscipinary approach, which combines the petrographic, morphological, and use-wear analysis of lithic tool implements based on both macroscopic and microscopic observations. The purpose of the use wear analysis was the identification of the different functions among these tools within their historical and archaeological context. Additionally, this study developed a precise terminology of manual movements and gestures associated with the use of these tools by combining ethnographical and experimental data with archaeological evidence.

As ceramicas a base de zirconia (Y-TZP) apresentam propriedades mecanicas superiores as das demais ceramicas odontologicas. Entretanto, o aumento do conteudo cristalino modificou suas caracteristicas de adesao a cimentos resinosos, tornando necessario o desenvolvimento de metodos mais efetivos de uniao a estes materiais. Este trabalho in vitro pretende, portanto, avaliar a influencia de diferentes tratamentos de superficie e de diferentes agentes de uniao na resistencia ao cisalhamento entre uma zirconia estabilizada por itrio e um agente cimentante autoadesivo (RelyX U100®/3M ESPE). Para tal, cilindros de PROCERA® Allzircon receberam como tratamento de superficie jateamento com oxido de aluminio (Al2O3 - 50 m) ou jateamento com o sistema Rocatec. Sobre a superficie tratada dos cilindros foram aplicados, de acordo com os diferentes grupos experimentais, o sistema adesivo Clearfil SE Bond® (Kuraray Co.), e os primers Metal Zirconia Primer (Ivoclar Vivadent) e Alloy Primer (Kuraray Co.) e, finalmente, o cimento resinoso adotado. Cada especime foi, entao, submetido ao teste de cisalhamento (0,05 mm/min), por meio da acao de uma alca de fio ortodontico passando o mais próximo possivel da interface adesiva. A analise de variancia a um criterios (ANOVA) e o teste de Tukey (p<0,05) mostraram que a realizacao do tratamento de superfície aumentou os valores de resistencia de uniao entre a ceramica e o cimento resinoso. O jateamento com o sistema Rocatec (15,33 MPa) apresentou valores significantemente maiores que o jateamento com Al2O3 (11,93 MPa). A aplicacao dos agentes de uniao resultou em uma maior resistencia adesiva, sendo que o sistema adesivo Clearfill SE Bond (17,07 MPa) teve um comportamento estatisticamente superior aos demais materiais. Entre os primers, o Metal Zirconia Primer (11,26 MPa) apresentou maior valor de resistencia de uniao que o Alloy Primer (10,01 MPa). Portanto, a associacao de um tratamento superficial com um agente de união e valida, ja que promoveu os maiores valores de resistencia adesiva. / Yttrium-stabilized tetragonal zircon polycrystal (Y-TZP) ceramics show better mechanical properties than other dental ceramics. However, the high crystalline content modified their adhesiveness to resin cements, making it extremely necessary to develop a more effective adhesive strategy between them. This in vitro study intends to evaluate the influence of different surface treatments and different bond agents on the shear bond strength between a Y-TZP and self-adhesive resin cement. PROCERA® Allzircon cylinders (3.5 mm in diameter) received a surface airborne abrasion treatment with 50 m aluminum-oxide (Al2O3) particles or with the Rocatec system. According to the experimental groups, the adhesive system Clearfil SE Bond® (Kuraray Co.), and the primers Metal Zirconia Primer (Ivoclar Vivadent) and Alloy Primer (Kuraray Co.) were applied on the treated surface of the cylinders, before the application of the adopted resin cement (RelyX U100®/3M ESPE). Each specimen was submitted to the shear bond strength test (0.5 mm/min), by the action of an orthodontic stainless steel ligature wire (0.5 mm in diameter) loop, wrapped around the resin cement, as close as possible to the adhesive interface. One way-ANOVA and Tukey´s post hoc tests (p<0.05) revealed that surface treatment increased bond strength between the ceramic and the resin cement. Silica coating with the Rocatec system (15.33 MPa) showed significantly higher values than airborne abrasion with Al2O3 (11.93 MPa). Application of all bond agents improved shear bond strength: adhesive system Clearfil SE Bond (17.07 MPa) showed better performance than the other evaluated materials, and Metal Zirconia Primer (11.26 MPa) showed higher bond strength values than Alloy Primer (10.01 MPa). Therefore, the association of a surface treatment with a bond agent is suitable, once it resulted in higher values of adhesive strength.

En teoría, el inicio del proceso de flotado de un pavimento de hormigón deberá coincidir con el tiempo de inicio de fraguado. Para resolver este problema, se desarrolló un modelo teórico sobre la evolución de la resistencia a penetración del hormigón antes del inicio de fraguado. Por otra parte, en esta Tesis Doctoral también se ha desarrollado un procedimiento muy sencillo para conocer la energía de activación del hormigón a través de ensayos de Vicat. En esta Tesis se ha hecho también un análisis comparativo de los seis tipos de acabados para pavimentos de hormigón más representativos mediante diferentes tipos de ensayos. Así como un análisis del comportamiento a impacto del pavimento de hormigón. Finalmente, se ha propuesto un modelo para conocer el comportamiento del pavimento sujeto a la abrasión. En él se obtuvo un nuevo modelo estadístico, que puede ser la base de una futura investigación en este campo. / Theoretically, the time of troweling a concrete pavement coincides with the setting time. To solve this problem, a theoretical model of the penetration resistance evolution of concrete during the setting time was developed. A new methodology to know the temperature influence on the setting times of concrete and on the time of toweling the pavement has been also performed.Besides, from six experimental pavements with the most representative type of finishing at the time of carrying out the study, a comparative analysis among them was done by means of different types of tests. Moreover, an analysis of the dynamic behavior of the pavement was carried out to know the protective effect of the type of finishing on the slab. Finally, a model for the dynamic behavior of a concrete pavement subjected to abrasion was made.

Ce travail de thèse a été consacré à l'étude des mécanismes de formation et de croissance des films oxydés par voie sèche (natifs ou ESO) et par voie aqueuse (films anodiques de passivation en solution borate de pH = 9,2) sur les alliages Fe-Ni (25, 50 & 75 at.% Ni) et Fe-Cr (5 à 30 at.% Cr). <br />Les films sont caractérisés (composition élémentaire et chimique, répartition en profondeur, épaisseur) par des techniques électrochimiques (réduction cathodique) et spectroscopiques associées à l'abrasion ionique (AES, XPS). Une approche quantitative développée en AES pour accéder aux modifications de composition et d'épaisseur produites pendant le vieillissement des films jusqu'à l'état (pseudo)-stationnaire a permis de dégager les mécanismes responsables. La croissance des films passifs anodiques se différencie de celle des films d'oxydation sèche par les réactions superficielles lentes de dissolution, de déshydratation et de déshydroxylation (Fe-Ni). On distingue : <br />(1) Une formation des films rapide par oxydation préférentielle du fer (Fe-Ni) ou du chrome (Fe-Cr) ; (2) Une croissance lente résultant de la compétition entre la mobilité ionique sous champ électrique (Cabrera-Mott) et l'effet barrière crée par les couches oxydées internes enrichies en fer (Fe-Ni) ou en chrome (Fe-Cr) (Macdonald) ; (3) L'efficacité de la couche barrière augmente aux teneurs croissantes en fer dans les alliages Fe-Ni et devient optimum dans les alliages Fe-Cr au-delà de 15 at.% Cr après vieillissement des films qui acquièrent une meilleure résistance à la corrosion.

CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / O trabalho tem como objetivo contribuir ao entendimento do efeito das caraterísticas superficiais no desgaste abrasivo com e sem efeito corrosivo. Utilizou-se o equipamento de micro-abrasão-corrosão desenvolvido no Laboratório de Tribologia e Materiais (LTM). Foi utilizado nos testes: amostras de aço inoxidável austenítico AISI 304, partículas abrasivas de sílica e velocidade de rotação de 150 rpm. Para a parte corrosiva foi usada solução eletrolítica com 1N de H2SO4. Para a influência da topografia de superfície do corpo de prova o aço AISI 304 foi preparado em lixas de carbeto de silício de granulometria #80 e #4000, e com disposições de lixamento perpendicular e paralelo com respeito ao sentido de rotação da esfera. Esferas de zircônia (Ø 25,4 mm) foram usadas como contra-corpos. Para avaliar a influência da natureza e evolução topográfica da superfície do contra-corpo usaram-se cinco contra-corpos esféricos (Ø 25,4 mm): um cerâmico (nitreto de silício, Si3N4), um metálico (aço AISI 52100) e três polímeros termoplásticos (polipropileno, PP, poliacetal, POM, e poliamida 6,6, PA 6,6); para os testes de micro-abrasão-corrosão foram usados um cerâmico (Si3N4) e um polímero termoplástico (PP). Foi acompanhada a evolução topográfica ao longo dos testes nos contra-corpos por meio de interferometria e perfilometría. O deslizamento das partículas abrasivas foi predominante nas calotas geradas em todos os testes realizados. A topografia de superfície do corpo e contra-corpo mostrou ter relação com a taxa de desgaste na micro-abrasão e micro-abrasão-corrosão. Topografia de superfície com parâmetros de rugosidade maiores apresentam maiores taxas de desgaste, tendo maior sensibilidade na micro-abrasão-corrosão. Atribuiu-se que, com maiores valores dos parâmetros de rugosidade, consegue-se maior efetividade no arraste e participação de partículas abrasivas no contato. / The aim of this work is to contribute to the understanding of the effect of surface characteristics on abrasive wear with and without corrosive effect. The micro-abrasion-corrosion apparatus developed at the Tribology and Materials Laboratory (LTM) was used. The following tests were used: AISI 304 austenitic stainless steel test specimens (body), silica abrasive particles and rotational speed of 150 rpm. For the corrosive analysis, an 1N H2SO4 electrolytic solution was used. For the influence of the surface topography of the specimen, the AISI 304 steel was grinded using silicon carbide (SiC) (#80 and # 4000), and tested with perpendicular and parallel arrangements with respect to the direction of rotation of the sphere. Zirconia balls (Ø 25.4 mm) were used as counter bodies. In order to analyze the influence of the nature and topographic evolution of the counter-body surface, five spherical counter bodies (Ø 25.4 mm) were used in the micro-abrasion tests: one ceramic (silicon nitride, Si3N4), one metal (AISI steel 52100) and three thermoplastic polymers (polypropylene, PP, polyacetal, POM and polyamide 6.6, PA 6.6); For the micro-abrasion-corrosion tests one ceramic (silicon nitride) and one thermoplastic polymer (PP) were used. The topographic evolution of the counter bodies was monitored along the tests through interferometry and profilometry. The grooving of the abrasive particles was predominant in the wear scars generated in all tests performed. The surface topographies of the body and counter-body showed to have relation with the wear rate in the micro-abrasion and micro-abrasion-corrosion tests. Higher roughness parameters induced higher wear rates, and show greater sensitivity in micro-abrasion-corrosion. It was attributed that higher values of the roughness parameters achieved greater effectiveness in the drag and participation of abrasive particles in the contact. / Tese (Doutorado)

This work focuses on the possibility of using recycled glass in the manufacture of blended portland cements. It examines the possibilities to improve pozzolanic properties of recycled glass with new milling processes, the formation of agglomerates material during the course of grinding and their subsequent effect on the hydration process of binders. It is also the optimization of the grinding process with respect to the wear of grinding bodies, grinding energy consumption and maximize the performance of the mill.

As ceramicas a base de zirconia (Y-TZP) apresentam propriedades mecanicas superiores as das demais ceramicas odontologicas. Entretanto, o aumento do conteudo cristalino modificou suas caracteristicas de adesao a cimentos resinosos, tornando necessario o desenvolvimento de metodos mais efetivos de uniao a estes materiais. Este trabalho in vitro pretende, portanto, avaliar a influencia de diferentes tratamentos de superficie e de diferentes agentes de uniao na resistencia ao cisalhamento entre uma zirconia estabilizada por itrio e um agente cimentante autoadesivo (RelyX U100®/3M ESPE). Para tal, cilindros de PROCERA® Allzircon receberam como tratamento de superficie jateamento com oxido de aluminio (Al2O3 - 50 m) ou jateamento com o sistema Rocatec. Sobre a superficie tratada dos cilindros foram aplicados, de acordo com os diferentes grupos experimentais, o sistema adesivo Clearfil SE Bond® (Kuraray Co.), e os primers Metal Zirconia Primer (Ivoclar Vivadent) e Alloy Primer (Kuraray Co.) e, finalmente, o cimento resinoso adotado. Cada especime foi, entao, submetido ao teste de cisalhamento (0,05 mm/min), por meio da acao de uma alca de fio ortodontico passando o mais próximo possivel da interface adesiva. A analise de variancia a um criterios (ANOVA) e o teste de Tukey (p<0,05) mostraram que a realizacao do tratamento de superfície aumentou os valores de resistencia de uniao entre a ceramica e o cimento resinoso. O jateamento com o sistema Rocatec (15,33 MPa) apresentou valores significantemente maiores que o jateamento com Al2O3 (11,93 MPa). A aplicacao dos agentes de uniao resultou em uma maior resistencia adesiva, sendo que o sistema adesivo Clearfill SE Bond (17,07 MPa) teve um comportamento estatisticamente superior aos demais materiais. Entre os primers, o Metal Zirconia Primer (11,26 MPa) apresentou maior valor de resistencia de uniao que o Alloy Primer (10,01 MPa). Portanto, a associacao de um tratamento superficial com um agente de união e valida, ja que promoveu os maiores valores de resistencia adesiva. / Yttrium-stabilized tetragonal zircon polycrystal (Y-TZP) ceramics show better mechanical properties than other dental ceramics. However, the high crystalline content modified their adhesiveness to resin cements, making it extremely necessary to develop a more effective adhesive strategy between them. This in vitro study intends to evaluate the influence of different surface treatments and different bond agents on the shear bond strength between a Y-TZP and self-adhesive resin cement. PROCERA® Allzircon cylinders (3.5 mm in diameter) received a surface airborne abrasion treatment with 50 m aluminum-oxide (Al2O3) particles or with the Rocatec system. According to the experimental groups, the adhesive system Clearfil SE Bond® (Kuraray Co.), and the primers Metal Zirconia Primer (Ivoclar Vivadent) and Alloy Primer (Kuraray Co.) were applied on the treated surface of the cylinders, before the application of the adopted resin cement (RelyX U100®/3M ESPE). Each specimen was submitted to the shear bond strength test (0.5 mm/min), by the action of an orthodontic stainless steel ligature wire (0.5 mm in diameter) loop, wrapped around the resin cement, as close as possible to the adhesive interface. One way-ANOVA and Tukey´s post hoc tests (p<0.05) revealed that surface treatment increased bond strength between the ceramic and the resin cement. Silica coating with the Rocatec system (15.33 MPa) showed significantly higher values than airborne abrasion with Al2O3 (11.93 MPa). Application of all bond agents improved shear bond strength: adhesive system Clearfil SE Bond (17.07 MPa) showed better performance than the other evaluated materials, and Metal Zirconia Primer (11.26 MPa) showed higher bond strength values than Alloy Primer (10.01 MPa). Therefore, the association of a surface treatment with a bond agent is suitable, once it resulted in higher values of adhesive strength.

Ce travail de thèse concerne la préparation et caractérisation des électrodes de carbone vitreuses (GC) modifiées par les films de groupements aryl (substitués) ou par phtalocyanines des métaux (MPc) et l'évaluation de leurs activités catalytiques envers la réduction électrochimique des nitrates dans les milieux aqueux acides. Les techniques adoptées pour la modification de surface du substrat (le GC) consistent à la réduction électrochimique des sels de diazonium ou à l'abrasion physique de la surface contre la poudre des MPc. En faisant intervenir un mécanisme complexe, y compris les phénomènes d'adsorption du réactif et du produit sur la surface, l’électroréduction de sels de diazonium entraîne au greffage des groupements aryls sur la surface. Les analyses voltamétriques détaillées ont rendu possible de conclure, décisivement pour la première fois, que la réduction commence à se faire sur la surface entière et, selon la concentration du diazonium et/ou l'efficacité du greffage, peut continuer à se faire à traverse les ouvertures microscopiques générés parmi les groupements aryl greffés sur la surface durant l'étape précédente de réduction (...) / This thesis work concerns about the preparation, characterization and catalytic activities evaluation of (substituted) aryl and metallophthalocyanines films-modified glassy carbon (GC) electrodes towards nitrate electrochemical reduction in acidic aqueous media. The surface modification techniques adopted consisted of the electroreduction of 4-substituted aryl diazonium salts and the metallophthalocyanine (MPc) powder abrasive adsorption. Through a complex mechanism involving the reactants and products adsorptions on the substrate surface, the electroreduction of aryl diazonium salts leads to the covalent attachment of mono as well as multilayers of aryl groups on the substrate surface. Detailed voltammetric investigations enabled to conclude, decisively for the first time, that the diazonium cation reduction begins to take place on the bulk (whole) surface and, depending upon the concentration and/or the products grafting efficiency, may continue to take place across the microscopic pinholes formed among the aryl groups grafted on the surface during the previous reduction step, thereby explaining the origin of the two reduction peaks in the voltammograms on GC surface. Electrochemical characterization of 4-nitrophenyl(NP)-modified surfaces in various types of aqueous media shed light over a number of mechanistic aspects of the process. Some new electrochemical evidences of the complications of surface coverage determination of redox centers from their electrochemical responses and of the role of aqueous electrolyte species transport on the responses have been presented. Some new phenomena or observations such as identification of the regions of votammograms corresponding to aminophenyl and hydroxyaminophenyl formation of the surface bound NP groups reduction, identification of the method of surface bound NP groups surface coverage estimation from the total width at half wave maximum (or electron transfer coefficient) of the responses, identification of the mechanistic aspects governing the differences of voltammetric behaviors of surface bound NP layers and the solution phase nitrobenzene, electrochemical (and XPS) evidences of the presence of azo type functionalities in the aryl films prepared from aryldiazonium electroreduction were also noticed. Barrier characters of the aryldiazonium electroreduction-derived N,N-dimethylaminophenyl-, nitrophenyl- and aminophenyl-modified surfaces towards ferricyanide, hexaammineruthenium and proton electroreductions in aqueous media indicate to the existence of electrostatic interactions among the surface bound and the solution phase ionic species. However, upon negative potential applications (such as those of water or nitrate reductions) surface attached films are partly or completely lost from the surface, as evidenced by the analytical scale measurements as well as from potentiostatic electrolysis of nitrate reduction in acidic aqueous media. Concerning the MPc-modified GC surfaces, the analytical scale measurements showed that among the phthalocyanines of copper, Iron and Nickel, the one of Cu is an optimizing material for the nitrate electrochemical reduction in, not previously reported, acidic aqueous media. The catalytic activity of MPc powders towards nitrate reduction in these media, which varies in the order CuPc > FePc > NiPc > GC appears to be related to the mental center and not with the phthalocyanine ring

When soluting the contruction of a grab dredger we will deal with suitable solution with reference to its using and capacity, possibilites of its setting in low temperatures and incidental aplication of the exchangeable abrasion - resistant mouldings. There will be made a calculation of forces taking effect on a grab dredger and a check calculation of the chosen structural parts.

At the beginning of this diploma thesis I describe the production of different types of threads (with special emphasis on the production of internal threads), then I discuss different types of application of abrasion resistant coating by PVD and CVD, I describe their main advantages and disadvantages. Further, this diploma thesis explains particular mechanisms and forms of tool wear on tool with coating. In the second part of this diploma thesis the analysis of the current status of the production of internal threads in the Rail (high-pressure chamber) is made. In the last part I compare six different threads cutters by the use of a scanning electron microscope