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- Documento de conferenciaAcceso AbiertoAnálisis bibliométrico de revistas científicas periódicas(2015) Tavani, Eduardo LuisEl objetivo de esta revisión fue caracterizar las bases de datos administradas por el Institute for Scientific Information, Elsevier y Scientific Electronic Library Online. Para dicho propósito se examinaron factor de impacto, índice de inmediatez y ranking de las revistas, además del índice h de los autores. Simultáneamente, se comparó el factor de impacto mostrado en los respectivos portales a fin de identificar sus principales características. Un análisis detallado de todas estas cuestiones y de otros aspectos formales que habitualmente no son cuantificados ni tampoco considerados por el investigador, ilustra los puntos que deben ser ponderados al momento de difundir la actividad científica ejecutada.
- Documento de conferenciaAcceso AbiertoAnálisis sedimentológico de facies de rampa externa: la Formación Agrio (Cretácico inferior), en el sector central de la Cuenca Neuquina, Argentina(2017) Comerio, Marcos; Fernández, Diana; Heredia, Arturo; Pazos, Pablo JoséMicrofacies of distal marine deposits of the Lower Cretaceous Agrio Formation – Pilmatué and Agua de la Mula members – in the Neuquén basin has been analyzed taken into account field data, whole-rock phase-minerals and clay mineralogy with X-ray diffraction, organic components and optical and electron microscopy. Depositional and diagenetic fabrics are compared for the lowermost part of both members. Two facies associations were distinguished that correspond to two depositional settings: distal outer ramp (FA-1); and, proximal outer ramp (FA-2). FA-1 is composed of sediments mainly deposited by suspension settling with calcareous microfossils partially preserved as fecal pellets and organo-minerallic aggregates related to high bioproductivity in the water column. Conversely, FA-2 is dominated by extrabasinal components with illite-rich clay- to silt-si - zed particle aggregates. Storm-influenced processes have a main role in sediment transportation and accumulation as well as controlling oxygenation pulses of the bottom waters. In addition, burial diagenesis was evaluated taking into account thermal maturity of organics together with diagenetic textures such as growth of authigenic minerals and mechanical and chemical compaction features. Due to clay mineral assemblages are mainly detrital in origin the possible effects of burial diagenesis on them cannot be directly evaluated.
- Documento de conferenciaAcceso AbiertoAplicación tecnológica de arcillas (acopios) de la sucesión superior de la formación Cerro Largo, Buenos Aires, Argentina(1996) Garrido, Liliana B.; Zalba, Patricia Eugenia; Pereira, EnriqueBased on mineralogical, physicochemical and technological characterization, the brownish and red clays of the upper pelitic succession of the Cerro Largo Formation, Sierras Bayas, Province of Buenos Aires, recently redefined as Olavarría Formation, composed of predominant illitic material, with impurities of quartz, calcite, siderite, hematite, goethite and pyrite, are suitable for red ceramic producís of low water absorption (15%). Preliminary controlled mixtures of the two varieties found (brownish and red), with different technological properties, constitute a better quality product than the ones obtained with the individual clays, wen with the addition of 3-5% bentonite.
- Documento de conferenciaAcceso AbiertoCentro de Tecnología de Recursos Minerales y Cerámica (CETMIC)(Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CICBA), 2016) Scian, Alberto NéstorExposición realizada en el marco del Encuentro del Ministerio de la Producción, Ciencia y Tecnología de la Provincia de Buenos Aires con autoridades y centros de la Comisión de Investigaciones Científicas de la Provincia de Buenos Aires. Exposiciones de los directores de los Centros de Investigación propios, asociados y vinculados.
- ArtículoEmbargadoCeramic material porous structure prepared using pore-forming additives(2017) Mocciaro, Anabella; Lombardi, María Bárbara; Scian, Alberto NéstorPorous ceramic materials exhibit high permeability, specific surface, and thermal shock resistance, and therefore they may be used successfully in the production of filters, membranes, and as a substrate for catalytic reactions, etc. One method for preparing high material porosity is addition of a pore-forming substance. Porosity (open and closed), pore size distribution, their size and shape, depend on the nature, amount, and morphology of pore-forming substance. In this article the effect is elucidated of three different types of carbon additives on porosity of ceramic prepared from clay and chemical binder precursor. Carbon materials are studied in an x-ray diffractometer. Ceramic material properties are studied using a mercury porosimeter, the Archimedes method, scanning electron and optical microscopes, and microcomputer tomography.
- ArtículoAcceso AbiertoCerámica roja artesanal contemporánea de Casira, Jujuy Argentina, caracterización del material(2016) Rendtorff Birrer, Nicolás Maximiliano; Serra, M.F.; Paltrinieri, Agustina; Hernandez, M.F.; Gauna, M.R.; Moyas, E.D.; Conconi, María SusanaLa cerámica actual elaborada en la Puna Argentina posee un valor cultural y económico significativo para la región. En particular en los talleres tradicionales de Casira se producen los principales exponentes de la cerámica popular de nuestro país. En el presente trabajo se propone establecer y reportar algunas de las propiedades y comportamientos tecnológicos de estos cerámicos. Se logró reportar las propiedades químicas, cristaloquímicas, microestructurales y mecánicas de un cerámico representativo. Luego se describió el comportamiento dilatométrico y la microestructura del mismo. Todas estas fueron correlacionadas con las materias primas empleadas y el método de fabricación. El análisis de las distintas caracterizaciones que se realizaron en este estudio permitió poner en contexto al cerámico y describir algunos de sus características tecnológicos que le confieren identidad única a estas cerámicas.
- ArtículoAcceso AbiertoLa ciencia y el arte cerámico(2017) Serra, María Florencia; Paltrinieri, Agustina; Rendtorff Birrer, Nicolás MaximilianoThis work was carried out in order to unravel the explicit relationship between the ceramic art with science and technology. We try to reveal how this relationship is reflected in the work of the ceramic artist Graciela Olio. In order to understand the areas that share science and art in her work, we interviewed the artist, who expressed the great importance of the experimental and methodological search in her art work.
- ArtículoAcceso AbiertoComparison of Imazalil Removal onto Montmorillonite and Nanomontmorillonite and Adsorption Surface Sites Involved: An Approach for Agricultural Wastewater Treatment(2015) Gamba, Martina; Flores, Federico Manuel; Madejová, Jana; Torres Sánchez, Rosa MaríaTo remove fungicide Imazalil (IMZ) (commercial formulation) from agricultural wastewater, adsorption was performed and compared among montmorillonite (Mt) and four organo-Mts (OMts), with different octadecyltrimethylammonium (ODTMA) loadings. The agglomerates size increase of OMts with respect to Mt found encourages the use of the former in agricultural wastewater treatment. Characterization of the OMts adsorbents by powder X-ray diffraction, infrared spectroscopy, and thermogravimetric analyses, indicated that ODTMA was present in the interlayer with different molecular arrangements, a diminution of the thermal stability of the OMts and an increase of ODTMA loading being observed at the same time. Zeta potential measurements showed electric surface charge reversion from negative to positive when the surfactant loading exceeded 100% of the clay cation exchange capacity (CEC). The IMZ adsorption on the raw Mt showed high pH dependence and affinity toward the fungicide, while OMts showed best IMZ adsorption capacity at high IMZ concentrations inversely related with the ODTMA loading. The characterization of IMZ−adsorbed samples indicated that for IMZ−Mt the interaction between IMZH+ and the siloxane surface was electrostatic. For IMZ−OMt samples the presence of new XRD and FTIR peaks suggested different IMZ interlayer arrangements and direct interaction with the surface, respectively. Analysis of zeta potential measurements indicated synergetic effects between the ODTMA and IMZ molecules at the external surface.
- ArtículoAcceso AbiertoLa confección de pigmentos en la producción de cerámica arqueológica (La Aguada, Catamarca, Argentina)(Sociedad Argentina de Antropología, 2002) Zalba, Patricia Eugenia; Zagorodny, Nora; Balesta, Bárbara; Morosi, Martín EduardoEn este trabajo se analizan muestras minerales clasificadas como "pigmentos" (Wolters F. m.s.) halladas en contextos funerarios en el cementerio de La Aguada (Depto. de Belén, Prov. de Catamarca). Este materialforma parte de la Colección Benjamín Muniz Barreto del Museo de La Plata. Las tumbas excavadas totalizan doscientas. En doce unidades de entierro se registraron diecisiete muestras de "pigmentos" presentando algunos de ellos, evidencias de haber sido amasados en forma de panes. Se realizó un análisis contextual de las tumbas en donde fueron localizados los pigmentos. Los mismos fueron sometidos a análisis mineralógicos y químicos a fin de determinar su composición y posible procedencia. Este estudio apunta a dilucidar una etapa dentro de la secuencia operativa de la manufactura cerámica, como también a recuperar la significación de la presencia de los materiales analizados en este tipo de contexto.
- Documento de conferenciaAcceso AbiertoConservacion de objetos expuestos a la luz y la influencia del medio ambiente en la conservacion del patrimonio(Laboratorio de Entrenamiento Multidisciplinario para la Investigación Tecnológica (LEMIT), 2002) Prieto, Nelly H.Este trabajo se basa en una observación museológica hacia la forma en que ciertos objetos están expuestos a la luz natural o artificial, sobre todo en los Museos de carácter histórico- ambientales. En nuestra circunstancia socio-cultural actual, es imprescindible una reflexión profunda respecto a la conservación del patrimonio. Muchas veces les damos distintas escalas de valores al patrimonio y nos olvidamos de las pequeñas cosas, que también hacen a la trascendencia de un hombre y/o de una circunstancia cultural de una región en una determinada época. (C. Moreno, 2000). (Párrafo extraído del texto a modo de resumen)
- ArtículoEmbargadoDawsonite in tuffs and litharenites of the Cerro Castaño member, Cerro Barcino Formation, Chubut Group (Cenomanian), Los Altares, Patagonia, Argentina(2011) Zalba, Patricia Eugenia; Conconi, María Susana; Morosi, Martín Eduardo; Manassero, Marcelo; Comerio, M.tractDawsonite, NaAlCO3(OH)2, occurs as a replacement, cement, and fracture filling in continental, zeolitized and silicified vitric tuffs and litharenites of the Cenomanian Cerro Castaño Member, Cerro Barcino Formation, Chubut Group, Patagonia, Argentina. Analcime is the only associated zeolite; it replaces the vitric masses and also fills fractures and cavities. Dawsonite and analcime display an inverse ratio. Textural relationships indicate that dawsonite is a pseudomorph after oligoclase, quartz, vitric shards, and vitric masses; it coexists with diagenetic quartz cement and postdates analcime, calcite, and hematite cements. Unaltered crystals of high sanidine postdate all other cements generated. Silicification of the tuffs is likely to have occurred in various stages during the diagenetic history of the sequence. Hypabyssal bodies of alkaline basic rocks of the El Buitre – El Canquel Formation, which intruded regionally the Cerro Castaño Member during Eocene time, are interpreted to be responsible for the introduction of CO2 gas at high partial pressures, together with sodium, which led to dawsonite formation. Diagenetic quartz, at a late stage of silicification, is related to the transformation of oligoclase and analcime to dawsonite, also releasing Na and Ca into the system. The d13C (PDB) values of dawsonite, in the range –1.2 to –2.4‰, attest to alkaline igneous activity in the Cerro Castaño Member during the Eocene and, in addition, set a limit on the age of the dawsonite.
- Contribucion a revistaAcceso AbiertoDense mullite–zirconia–zirconium titanateceramiccomposites by reactionsintering(2015) Rendtorff Birrer, Nicolás Maximiliano; Gómez, Sofía; Gauna, Matías; Conconi, María Susana; Suárez, Gustavo; Aglietti, EstebanMaterials from the Al2O3–SiO2–ZrO2and the Al2O3–SiO2–ZrO2–TiO2systems have several high temperature applications because they present the good refractoriness, chemical inertness, adequate mechanical and thermo-mechanical behaviors with a relatively good cost: performance ratio. In this work stoichiometric (3:2:1) molar incompatible mixtures of alumina (Al2O3), zircon (ZrSiO4) and titania (TiO2) were slip casted and sintered in a 1300–1500°C temperature range in order to obtain mullite (3Al2O3·2SiO2), zirconia (ZrO2) and zirconium titanate (ZrTiO4) dense triple ceramic composite. Both sintering and reaction occurred after the thermal treatments. Reaction progress and densification evolutions were established. Dense Triplex composite materials were achieved after 1500°C treatments. The reaction-sintering was followed by XRD, TG–DTA, and dilatometry. Densification started at 1100°C and the chemical reactions only started above 1300°C. Aluminum titanate (Al2TiO5) was found to be an intermediate of the reaction after 1400°C treatments. Materials treated below 1300°C presented a partial densification of the unreacted starting powders. Resulting ceramic materials were characterized. The crystalline phases were evaluated, as well as the texture properties. The achieved microstructure consisted in interlocked multiphase ceramic with zirconia (monoclinic) grains. The achieved Hv andKICreached 9GPa and 4.3MPam1/2respectively. The dense and interlocked ceramic microstructure and relative high mechanical properties of the developed material encourages several high temperature applications. Finally it can be pointed out that after 1500°C treatments some detrimental grain growth was observed.
- ArtículoAcceso AbiertoDesarrollo de materiales cerámicos refractarios de baja densidad a partir de agentes ligantes nanoestructurados y carbón(2017) Mocciaro, Anabella; Lombardi, María Bárbara; Scian, Alberto NéstorEn este trabajo se estudia el desarrollo de materiales cerámicos refractarios de baja densidadutilizando un agente ligante que genere, luego de calcinados, nanoestructuras cerámicas.Además, se adicionaron al sistema fuentes de carbono como agentes formadores de poroscon el objetivo de disminuir la densidad final del material. Como materias primas se utiliza-ron dos arcillas caoliníticas argentinas, gel de fosfato de aluminio que actúan como agentesligantes y distintas fuentes de carbón (carbón residual de petróleo, carbón vegetal y negrode humo). Se obtuvieron cerámicos con densidades menores a 2 g/cm3y variada resisten-cia mecánica a la flexión (8,02-26,87 MPa). Se observó que las propiedades de los materialescerámicos, para materiales desarrollados bajo iguales condiciones, varían según la fuentede carbono utilizada.
- Documento de conferenciaAcceso AbiertoDoes “black shales” suffice for lithological changes in transgressive facies? The case of the Agua de la Mula Member (Agrio Formation), Neuquen Basin, Argentina(2014) Comerio, Marcos; Pazos, Pablo José; Zalba, Patricia Eugenia“Black shales” ¿Es suficiente para denotar cambios litológicos en facies transgresivas? Caso del Miembro Agua de la Mula (Formación Agrio), Cuenca Neuquina, Argentina Se estudió, por medio de microscopía óptica y electrónica de barrido, así como por difracción de rayos X y contenido de carbono orgánico, la variabilidad de litofacies correspondiente a la etapa transgresiva basal del Miembro Agua de la Mula de la Formación Agrio, a escala de cuenca. Se pudieron diferenciar tres grupos de sedimentitas de grano fino: (i) un grupo dominados por componentes intracuencales derivados de la producción orgánica y carbonática, (ii) otro con altos porcentajes de componentes terrígenos y (iii) un tercer grupo con predominio de minerales autigénicos. Además de procesos de baja energía, como el de decantación a partir de material en suspensión, se documentaron corrientes tractivas, desarrollo de matas microbianas y bioturbación. Los procesos sedimentarios reconocidos sugieren que durante la depositación los escenarios fueron dinámicos y variables a distintas escalas, tanto en sentido lateral como vertical, y no relativamente estables como antes se presumía.
- ArtículoEmbargadoEffect of raw material milling on ceramic proppants properties(2018) Mocciaro, Anabella; Lombardi, María Bárbara; Scian, Alberto NéstorLow density and high breakage resistance ceramic proppants were developed from kaolin, bauxite and monoaluminum phosphate (MAP). The effect of the particle size on the raw materials over the density, the open porosity and the breakage resistance of the proppants was evaluated. The phase composition and the structure of the proppants due to the milling process were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and pore size distribution by mercury intrusion. The proppants obtained with raw materials of smaller size improved its breakage resistance and developed a smaller open pore size, achieving an apparent density of 2.4 g/cm3 with a breakage ratio of 9.61% under 64 MPa. Some properties of the AG3 proppants with sand, low density ceramic proppants of the literature and commercial low density ceramics proppants were compared.
- Documento de conferenciaAcceso AbiertoElaboración simple de pelets carbonosos para remover arsénico(2016) Bursztyn Fuentes, Amalia Lara; Arnal, Pablo Maximiliano; Mieres, Noelia; Long, Leonel; Ormaechea, MartinaObjetivo: Investigar y desarrollar un proceso simple - en el marco de las tecnologías emergentes- que permita obtener un material carbonoso que reduzca la concentración de As en agua de bebida por debajo del límite permitido por la legislación vigente(< 10 ppb) a pequeña escala y con recursos locales.
- ArtículoAcceso AbiertoFiring transformations of an argentinean calcareous commercial clay(Associacao Brasileira de Cerâmica, 2013) Serra, Maria Florencia; Conconi, María Susana; Suárez, Gustavo; Aglietti, Esteban Fausto; Rendtorff Birrer, Nicolás MaximilianoMineralogical transformations caused by firing are usually studied by XRD methods only semi-quantitatively. In this work the original mineral disappearance and the neo-mineralization were evaluated quantitatively. Furthermore an indirect non crystalline phase quantification was performed under 1100 ºC was also carried out using the quartz content as internal standard. This study specifically discusses the behavior of an Argentinean white calcareous earthenware commercial when subjected to traditional ceramic firing, besides the technological importance of this particular material, it acts as a model for other clay based ceramic materials. Materials were subjected to thermal treatments between 700 ºC and 1100 ºC. A preliminary sintering characterization was carried out by contraction and porosity evolution. Simultaneous thermogravimetric and differential thermal analysis (TG-DTA) was carried out to elucidate the actual temperature at which the chemical changes occur. Finally, a quantitative analysis based on the Rietveld refinement of the X-ray diffraction patterns was performed to characterize the crystalline phases present in both the clay and in the materials obtained after different thermal treatments. The actual chemical reactions are proposed. The phases identified after firing at traditional working temperature (1040 ºC) are quartz, plagioclase, and the Spinel type alumino-silicate, accompanied by the non-diffracting un-reacted metakaolin and some amount of amorphous glassy phase. At intermediate temperatures (900 ºC) the presence of gehlenite was also detected. The carbonates (calcite and dolomite) presence and decomposition were also evaluated and demonstrated to determine the sintering characteristics of this material.
- ArtículoAcceso AbiertoGlobal diversity, population stratification, and selection of human copy number variation(2015) Sudmant, Peter H.; Mallick, Swapan; Nelson, Bradley J.; Hormozdiari, Fereydoun; Krumm, Niklas; Huddleston, John; Coe, Bradley P.; Baker, Carl; Nordenfelt, Susanne; Bamshad, Michael; Jorde, Lynn B.; Posukh, Olga L.; Sahakyan, Hovhannes; Watkins, Scott; Yepiskoposyan, Levon; Abdullah, M. Syafiq; Bravi, Claudio M.; Capelli, Cristian; Hervig, Tor; Wee, Joseph T. S.; Tyler-Smith, Chris; van Driem, George; Gallego Romero, Irene; Jha, Aashish R.; Karachanak-Yankova, Sena; Toncheva, Draga; Comas, David; Henn, Brenna; Kivisild, Toomas; Ruiz-Linares, Andres; Sajantila, Antti; Metspalu, Ene; Parik, Jüri; Villems, Richard; Starikovskaya, Elena B.; Ayodo, George; Beall, Cynthia M.; Di Rienzo, Anna; Hammer, Michael; Khusainova, Rita; Khusnutdinova, Elza; Klitz, William; Winkler, Cheryl; Labuda, Damian; Metspalu, Mait; Tishkoff, Sarah A.; Dryomov, Stanislav; Sukernik, Rem; Patterson, Nick; Reich, David; Eichler, Evan E.In order to explore the diversity and selective signatures of duplication and deletion human copy number variants (CNVs), we sequenced 236 individuals from 125 distinct human populations. We observed that duplications exhibit fundamentally different population genetic and selective signatures than deletions and are more likely to be stratified between human populations. Through reconstruction of the ancestral human genome, we identify megabases of DNA lost in different human lineages and pinpoint large duplications that introgressed from the extinct Denisova lineage now found at high frequency exclusively in Oceanic populations. We find that the proportion of CNV base pairs to single nucleotide variant base pairs is greater among non-Africans than it is among African populations, but we conclude that this difference is likely due to unique aspects of non-African population history as opposed to differences in CNV load.
- ArtículoAcceso AbiertoHydrothermal Stability of Ru/SiO2–C: A Promising Catalyst for Biomass Processing through Liquid-Phase Reactions(MDPI (Multidisciplinary Digital Publishing Institute), 2017) Gatti, Martín; Lombardi, María Bárbara; Gazzoli, Delia; Santori, Gerardo F.; Pompeo, Francisco; Nichio, NoraIn this work, structural and morphological properties of SiO2–C composite material to be used as support for catalysts in the conversion of biomass-derived oxygenated hydrocarbons, such as glycerol, were investigated in liquid water under various temperatures conditions. The results show that this material does not lose surface area, and the hot liquid water does not generate changes in the structure. Neither change in relative concentrations of oxygen functional groups nor in Si/C ratio due to hydrothermal treatment was revealed by X-ray photoelectron spectroscopy (XPS) analysis. Raman analysis showed that the material is made of a disordered graphitic structure in an amorphous silica matrix, which remains stable after hydrothermal treatment. Results of the hydrogenolysis of glycerol using a Ru/SiO2–C catalyst indicate that the support gives more stability to the active phase than a Ru/SiO2 consisting of commercial silica.
- ArtículoAcceso AbiertoThe ichnogenus Dictyodora from Late Silurian deposits of central-western Argentina: Ichnotaxonomy, ethology and ichnostratigrapical perspectives from Gondwana(2015) Pazos, Pablo José; Heredia, Arturo; Fernández, Diana E.; Gutiérrez, Carolina; Comerio, MarcosThe association of trace fossils from the Late Silurian Río Seco de los Castaños Formation in central-western Argentina (San Rafael Block) is mainly composed of Dictyodora, including D. scotica, D. tenuis and a new ichnospecies named D. atuelica. The latter shows a tendency to migrate to a deeper level – analogous to D. liebeana’s – which reflects more sophisticated behavioural patterns. The Dictyodora ichnospecies (one of the most diverse assemblages in Gondwana) coexists with Nereites. SEM observations and EDS analyses suggest that the wall structure of Dictyodora could be the result of an activity other than the traditional suggestion of respiration, e.g., feeding. The succession, including some of the levels containing Dictyodora, presents microbially induced sedimentary structures (MISS) that would indicate a photic zone. This discovery favours previous deltaic interpretations instead of the deep-sea fan deposits traditionally suggested for the Siluro-Devonian greywackes of the Cuyania terrane, and particularly for this unit. The abundant Dictyodora, Nereites, Zoophycos and undermat miners ichnofossils, as well as the scarce arthropod trackways, resemble older records in Europe and North America. The studied section is very well ageconstrained, and the autochthonous Gondwana ichnofauna permits to cast doubt on previous interpretations, suggesting that after the Ordovician, microbial mats retreated to marginal marine environments and then spread later in the Carboniferous. More importantly, the occurrence of Dictyodora and Nereites in beds that bear abundant wrinkle structures or records of biofilms in some places is challenging with regard to deep-sea interpretations. Dictyodora is probably not a good stratigraphic indicator, and the provincialism suggested for this ichnogenus may be an artefact of the lack of more complete records in Gondwana.