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Ítem Deposition and characterization of duplex treated coating system applied on hot work steel AISI H13(Universidad Simón Bolívar, 201-08-08) Bejarano Gaitán, Gilberto; Arroyave Franco, Mauricio; Gómez Botero, Maryori; Universidad EAFIT. Departamento de Ciencias Básicas; marroya5@eafit.edu.co; Electromagnetismo Aplicado (Gema)AISI H13 steel is widely used for extrusion moulds and other hot work tools fabrication, due to its high toughness, strength and hardness around 56 HRC (Rockwell C) -- However, this steel possesses a relatively low wear resistance, which reduces its life time under high loading conditions -- The aim of this work was to enhance the wear resistance of the steel H13 using the following surface treatments:austenitizing + quenching + tempering (further called “tempering”), tempering and bath nitriding, tempering and coated with chromium nitride (CrN), tempering + bath nitriding + coated with CrN (further called “Duplex coating”) -- The properties of the treated samples were compared with each other in dependence of the made surface treatment -- The coatings were deposited using the r.f. balanced magnetron sputtering deposition technique -- The total thickness of the coatings was maintained at 5 µm, while the thickness of the nitrided zone was approximately 140 µm -- The microstructure and the crystalline phase composition were investigated by Scanning -- Electron Microscopy (SEM) and X-ray diffraction (XRD) technique, respectively -- The hardness and the adhesion of the coatings were determined by micro indentation measurements and the Rockwell indentation test, respectively -- The wear resistance of the coatings was evaluated using ball on disc tests -- The duplex treated samples presented a hardness three order of magnitude higher and showed a wear rate six times smaller than those samples only temperedÍtem Vocabulario geología y geomorfología(1989-01-01) Hermelin, Michel; Hermelin, Michel; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y TectónicaÍtem Geología y ciudades(1992-01-01) Hermelin, Michel; Hermelin, Michel; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y TectónicaÍtem Erosional and depositional features produced by a convulsive event, San Carlos, Colombia, Sept. 21st, 1990(Springer Verlag, 1992-01-01) Hermelin, Michel; Hermelin, Michel; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y TectónicaÍtem Los suelos del Oriente Antioqueño como recurso no renovable(1992-01-01) Hermelin, Michel; Hermelin, Michel; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y TectónicaÍtem Erosional and depositional features produced by a convulsive event, San Carlos, Colombia, September 21, 1990(Springer Verlag, 1992-04-01) Hermelin Arbaux, Michel; Mejía, Oscar; Velásquez, Elkin; Universidad EAFIT. Departamento de Geología; Michel Hermelin Arbaux (hermelin@eafit.edu.co); Geología Ambiental e Ingeniería Sísmica (GIGAI)Le bassin supdricur de la riviC:re San Carlos, situd sur le flanc est de la Cordill~re Centrale de Colombie, a dtd aft'ectd par un << ~vdnemertt convulsif ,, le 2I septembre 1990. Une averse de 208 ram. ~,ans 6.quiva/enl historique dans ia zone, a cau.,,6 lu mort de 20 personnes et d'importants ddgfits. Plus de cent couldcs boueuses se sont produites sur les versants les plus 61evds et les plus inclinds, quelle que soil la nature du sol. Dans les zones moyennes du bassin Its lits des torrents ont did dlurgis et approfondis p~u" le creusement d'anciens ddp6ts torrentiels et de versants et de la granodiorite mdtdorisde. Une grande quantit6, de matdriau a dt~. drod~e, y compris des blocs d'un diametre atteignant 8 m. Les d@6ts montrent une diffdrenciation classique : les blocs accumules sur la pattie haute, les sables sur le cours moyen, et les argiles ont dr6. transport6es jusqu'au rdservoir de Punchin'a, environ 20 km en aval. Une couche de cendres volcaniques qui recouvre les ddp6ts torrentiels anciens montre des associations mindralogiques qui pet, vent etre corrdldes avec d'autres cendres trouvdes plus 5, I'est, dont I'&ge radiomdtrique cst de I0.500 ans BP environÍtem Stratigraphy of volcanic ashes from South Antioquia, Colombia(1993-01-01) Hermelin, Michel; Hermelin, Michel; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y TectónicaÍtem Stone line in Antioquia highlands(1993-01-01) Hermelin, Michel; Hermelin, Michel; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y TectónicaÍtem Specification for a Process Planning Enabling Platform(Wiley, 1995) Carr, K.; Hetem, V.; Lucenti, M.; Ruíz, Ó.; Zhu, X.; Ferreira, P.M.; Lu, S.C.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThe objective of this research is the specification of an enabling platform for process planning system development -- This work was done under a contract issued by Computer Aided Manufacturing-International to the University of Illinois -- An analysis framework is developed that integrates inter-related process planning activities by transforming inputs and controls through mechanisms into outputs -- An object-oriented approach is used to define the object model and thereby facilitate the configuration of a process planning system by providing standardised data objects and fundamental library routines -- The proposed software structure is layered with specific modules designed to support integration and data exchange -- The development domain is machining and includes part understanding, process selection and ordering, equipment specification, setup and operation planning, manufacturability analysis, and plan evaluation and documentationÍtem Las Ciencias de la Tierra y el medio Ambiente en Colombia(Academia Colombiana de Ciencias Exactas, Físicas y Naturales, 1995-01-01) Hermelin, Michel; Hermelin, Michel; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y TectónicaÍtem Using Gröbner Bases in Kinematic Analysis of Mechanisms(Birkhäuser Verlag, 1996) Ruíz, Óscar E.; Ferreira, Placid M.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEÍtem Algebraic geometry and group theory in geometric constraint satisfaction for computer-aided design and assembly planning(Taylor & Francis, 1996) Ruíz, Óscar E.; Ferreira, Placid M.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEMechanical design and assembly planning inherently involve geometric constraint satisfaction or scene feasibility (GCS/SF) problems -- Such problems imply the satisfaction of proposed relations placed between undefined geometric entities in a given scenario -- If the degrees of freedom remaining in the scene are compatible with the proposed relations or constraints, a set of entities is produced that populate the scenario satisfying the relations -- Otherwise, a diagnostic of inconsistency of the problem is emitted -- This problem appears in various forms in assembly planning (assembly model generation), process planning, constraint driven design, computer vision, etc -- Previous attempts at solution using separate numerical, symbolic or procedural approaches suffer serious shortcomings in characterizing the solution space, in dealing simultaneously with geometric (dimensional) and topological (relational) inconsistencies, and in completely covering the possible physical variations of the problem -- This investigation starts by formulating the problem as one of characterizing the solution space of a set of polynomials -- By using theories developed in the area of algebraic geometry, properties of Grobner Bases are used to assess the consistency and ambiguity of the given problem and the dimension of its solution space -- This method allows for die integration of geometric and topological reasoning -- The high computational cost of Grobner Basis construction and the need for a compact and physically meaningful set of variables lead to the integration of known results on group theory -- These results allow the characterization of geometric constraints in terms of the subgroups of the Special Group of Euclidean displacements in E^3, SE(3) -- Several examples arc developed which were solved with computer algebra systems (MAPLE and Mathematica) -- They are presented to illustrate the use of the Euclidean group-based variables, and to demonstrate the theoretical completeness of the algebraic geometry analysis over the domain of constraints expressible as polynomialsÍtem Using Gröbner Bases in Kinematic Analysis of Mechanisms(1996-01-01) RUIZ, OSCAR EDUARDO; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEÍtem Late Cenozoic tectonics and paleomagnetism of North Cauca Basin intrusions, Colombia Andes: Dual rotation modes(ELSEVIER SCIENCE BV, 1996-01-01) Sierra, Gloria Maria; Sierra, Gloria Maria; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y TectónicaÍtem Algebraic Geometry and Group Theory in Geometric Constraint Satisfaction for Computer Aided Design and Assembly Planning(1996-01-01) RUIZ, OSCAR EDUARDO; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEÍtem Late cenozoic tectonics and paleomagnetism of North Cauca Basin intrusions, Colombian Andes: Dual rotation modes(ELSEVIER SCIENCE BV, 1996-09-15) MacDonald, WD; Estrada, JJ; Sierra, GM; Gonzalez, H; MacDonald, WD; Estrada, JJ; Sierra, GM; Gonzalez, H; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y TectónicaFurther paleomagnetic results are reported from 18 sites in Late Tertiary hypabyssal igneous rocks adjacent to the Romeral fault system which forms the eastern boundary of the North Cauca Basin. The paleomagnetic directions in these massive igneous intrusions are distributed in vertical planes parallel to the adjacent Romeral suture zone. Two modes of rotation, involving non-coherent rotations about horizontal rotation axes and coherent rotations about vertical rotation axes, can explain the observed remanence patterns. The paleovectors have been rotated variably (non-coherently), both upwards and downwards, through up to nearly 90°, about horizontal axes which are perpendicular to the prevailing structural trend. These horizontal axis rotations are believed to be associated with shear gradients operating on rough projections or "asperities" on otherwise approximately lenticular bodies. These give rise to torques which cause variable horizontal axis rotation along splay faults of the Romeral and adjacent systems. In addition, the north segment of the zone of intrusions has been rotated coherently, i.e. through uniform angles, of about 30° counterclockwise, about vertical axes relative to the southern zone. The change in declination trend corresponds to a major change in trend of the Romeral suture zone. The vertical-axis rotations are believed to represent regional-scale kinking of vertical lenti-laminar fault panels of crust accreted to the paleocontinental margin along the Romeral suture. It is hypothesized that oblique transpression has pressed the zone of intrusions into the Caldas Re-entrant in the paleocontinental margin.Ítem Interfaz AIS para aplicaciones en CAD/CAM/CG(1997) Ruíz S., Óscar E.; Saldarriaga, Jairo A.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAELos modeladores geométricos más comunes en el mercado ofrecen, además de sus servicios de modelado, una API (Application Programming Interface) que permite la construcción de aplicaciones o software cliente -- Estas aplicaciones aprovechan los servicios básicos del modelador para proveer tareas específicas -- Sin embargo las diferencias entre API´s de distintos modeladores imposibilita el intercambio del software cliente entre ellos -- Application Interface Specification -AIS- es una API genérica para ser usada por aplicaciones cliente de los modeladores geométricos -- Este artículo reporta la implementación de AIS sobre AutoCAD® y MicroStation® y discute aspectos importantes de dicha implementación -- Además presenta una aplicación cliente neutra que habla lenguaje AIS y por lo tanto se ejecuta transparentemente sobre los dos modeladores -- AIS se presenta como una alternativa económica para escribir aplicaciones de CAD/CAM/CG -- Futuros desarrollos incluyen la implementación de AIS para labores gráficas y/o de base de datosÍtem Sistemas Hipermedios Colaborativos(1997-01-01) ATUESTA, MARIA DEL ROSARIO; ATUESTA, MARIA DEL ROSARIO; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las ComunicacionesÍtem Ambientes de Aprendizaje para el tercer milenio(1997-01-01) ATUESTA, MARIA DEL ROSARIO; ATUESTA, MARIA DEL ROSARIO; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las ComunicacionesÍtem El tema de Tesis, una decisión importante para el pais(Fondo Editorial Universidad EAFIT, 1997-06-01) Arango, Iván Darío; Arango, Iván Darío; Universidad EAFIT. Departamento de Ingeniería Mecánica; Mecatrónica y Diseño de Máquinas