Scientific Papers in SCI

2013


Title: Heat capacity of Bio-SiC and SiC/Si ecoceramics prepared from white eucalyptus, beech, and sapele tree wood
Author(s): Smirnov, IA; Smirnov, BI; Orlova, TS; Wlosewicz, D; Hackemer, A; Misiorek, H; Mucha, J; Jezowski, A; Ramirez-Rico, J; Martinez-Fernandez, J
Source: Physics of the Solid State, 55 (2013) 454-460

abstract | fulltext

This paper reports on measurement of the heat capacity at constant pressure C p of silicon bio-carbide prepared within the 5–300 K temperature interval from beech tree wood (bio-SiC(BE)), and within 80–300 K, from tree wood of sapele (bio-SiC(SA)), as well as SiC/Si ecoceramics of beech, sapele, and white eucalyptus wood. It has been shown that in bio-SiC(BE) the measured heat capacity contains a significant contribution of surface heat capacity, whose magnitude decreases with increasing temperature. Of the ecoceramics, only SiC/Si(SA) characterized by a high enough porosity has revealed a small contribution to the heat capacity coming from its surface component. The experimental results obtained are discussed.

February, 2013 | DOI: 10.1134/S1063783413020285

Title: Thermopower of Bio-SiC and SiC/Si ecoceramics prepared from sapele tree wood
Author(s): Smirnov, IA; Smirnov, BI; Orlova, TS; Sulkovski, C; Misiorek, H; Muha, J; Jezowski, A; Ramirez-Rico, J; Martinez-Fernandez, J
Source: Physics of the Solid State, 55 (2013) 54-59

abstract | fulltext

The thermopower coefficients of bio-SiC and SiC/Si ecoceramics prepared from sapele tree wood have been measured in the temperature interval 5–300 K. The measurements have been performed both along and perpendicular to empty (bio-SiC), as well as empty and partially silicon-filled (SiC/Si) channels in the samples. In bio-SiC, a contribution to thermopower associated with electron drag by phonons has been shown to exist within the temperature interval 5–200 (250) K. No such effect is realized in SiC/Si. This is assumed to derive from the presence in this material of heavily doped silicon embedded in SiC channels and the dominant part it plays in the behavior of the thermopower of this ceramics. The results obtained for the thermopower are compared with the available data for bio-SiC prepared from white eucalyptus tree wood and heavily doped bismuth.

January, 2013 | DOI: 10.1134/S1063783413010307

Title: Structure-mediated transition in the behavior of elastic and inelastic properties of beach tree bio-carbon
Author(s): Kardashev, BK; Orlova, TS; Smirnov, BI; Gutierrez, A; Ramirez-Rico, J
Source: Physics of the Solid State, 55 (2013) 1884-1891

abstract | fulltext

Microstructural characteristics and amplitude dependences of the Young modulus E and of internal friction (logarithmic decrement δ) of bio-carbon matrices prepared from beech tree wood at different carbonization temperatures T carb ranging from 600 to 1600°C have been studied. The dependences E(T carb) and δ(T carb) thus obtained revealed two linear regions of increase of the Young modulus and of decrease of the decrement with increasing carbonization temperature, namely, ΔE ∼ AΔT carb and Δδ ∼ BΔT carb, with A ≈ 13.4 MPa/K and B ≈ −2.2 × 10−6 K−1 for T carb < 1000°C and A ≈ 2.5 MPa/K and B ≈ −3.0 × 10−7 K−1 for T carb > 1000°C. The transition observed in the behavior of E(T carb) and δ(T carb) at T carb = 900–1000°C can be assigned to a change of sample microstructure, more specifically, a change in the ratio of the fractions of the amorphous matrix and of the nanocrystalline phase. For T carb < 1000°C, the elastic properties are governed primarily by the amorphous matrix, whereas for T carb > 1000°C the nanocrystalline phase plays the dominant part. The structurally induced transition in the behavior of the elastic and microplastic characteristics at a temperature close to 1000°C correlates with the variation of the physical properties, such as electrical conductivity, thermal conductivity, and thermopower, reported in the literature.

September, 2013 | DOI: 10.1134/S1063783413090151

Title: Estudio in-situ de la transformación térmica de limonita utilizada como pigmento procedente de Perú
Author(s): Romero-Gomez, P; Gonzalez, JC; Bustamante, A; Ruiz-Conde, A; Sanchez-Soto, PJ
Source: Boletin de la Sociedad Española de Cerámica y Vidrio, 52 (2013) 127-131

abstract | fulltext

Se ha realizado un estudio cinético de la transformación térmica de limonita [FeO(OH).nH2O] mediante análisis térmico gravimétrico (TGA), termodifracción de rayos X (DRX) y espectroscopía μ-Raman. La muestra estudiada fue extraída de un yacimiento en el distrito de Taraco, provincia de Huancané, Región de Puno (Perú). La técnica DRX en polvo identificó la fase goetita como el principal componente mineralógico, además de cuarzo. La muestra se sometió a un tratamiento térmico
in-situ en un intervalo de temperaturas de 100 a 500 °C en atmósfera de aire e inerte (nitrógeno) y se estudió por DRX. Los resultados han mostrado que la fase goetita permanece estable desde la temperatura ambiente hasta 200 °C. A partir de los 250 °C se produce una transformación de fase α-FeO(OH)→α-Fe2O3
con un cambio cromático, es decir, el paso de la fase
hidroxilada goetita (amarillo) a la fase oxidada hematites (rojo) con una pérdida de peso de un 8 %, teniendo como evidencia la evolución de los perfiles de difracción y los resultados de ATG. Los espectros μ-Raman del tratamiento térmico in-situ corroboran que se produce también una transición de fase a la temperatura de 290 °C a través de la transformación de las bandas Raman características de la fase goetita hacia la fase hematites en el rango de frecuencias de 200 a 1800cm-1.

May, 2013 | DOI: 10.3989/cyv.162013

Title: Planning collection and solid waste flow (construction and demolition, concrete, ceramics and others) by utilizing a computerized tool for sustainable management
Author(s): Garzon, E; Sanchez-Soto, PJ
Source: Boletin de la Sociedad Española de Cerámica y Vidrio, 5 (2013) V-XIV (Notas Técnicas)

abstract | fulltext

Se presenta un procedimiento para la planificación de recogida y flujo de los residuos sólidos (de construcción y demolición, hormigón, cerámica, vidrio y otros) basado en la utilización de una herramienta informatizada, para conseguir una optimización de su gestión. Dicho procedimiento parte de normativa establecida según un Plan Director Territorial de la Gestión de Residuos Sólidos Urbanos (RSU) aprobado en una Comunidad Autónoma, en este caso se particulariza a la de Andalucía, tomando como ejemplo el volumen de residuos que se producen en una colectividad de tamaño medio (provincia de Almería), siendo extensible a otras mayores en población y territorio, disponiendo de datos actualizados.
El procedimiento utiliza una herramienta informática de gran difusión en el mundo, como es Google Earth y, de este modo, genera un número de “Centros deTransferencia” con objeto de minimizar el gasto de transporte, partiendo de una premisa previa en cuanto a distancia entre núcleos poblacionales y centros de tratamiento. Los Centros generados con la aplicación del procedimiento se pueden visualizar en un mapa topográfico, con áreas de influencia y vías de acceso a los mismos y se le pueden asociar una serie de datos tabulados con información adicional de utilidad. El procedimiento propuesto se va retroalimentando de manera constante con datos reales e información de campo, permitiendo a las empresas que producen residuos de distinta tipología como son los residuos de construcción y demolición principalmente, pero también hormigón, cerámica, vidrio, mezclas de todos ellos, residuos clasificados como peligrosos e incluso de otros materiales, a la propia administración y a la sociedad, en general, conocer las tasas de cada planta de tratamiento y qué se hace con los residuos entregados para contribuir a la reducción del impacto medioambiental de los mismos y a su gestión sostenible.
 

September, 2013 | DOI: 10.3989/cyv.2013.v52.i5

Title: Porous Aluminas: The biotemplate method for the synthesis of stable high surface area aluminas
Author(s): Guerrero, MB; Maqueda, LP; Castro, PP; Cosp, JP
Source: Boletin de la Sociedad Española de Cerámica y Vidrio, 52 (2013) 251-267

abstract | fulltext

Development of porous alumina has been the objective of numerous studies in recent decades, due to the intrinsic properties of aluminium oxide, such as high melting point, low thermal conductivity, chemical inertness and corrosion resistance which, in addition to a high surface area and permeability, make aluminas being used for many different industrial and technical applications. The crystallographic and textural stability of alumina acquires significant importance in those processes involving high temperatures; however, most of the synthesis methods yield metastable oxides of little interest in high-temperature processes due to the transformation to alpha phase, with the consequent reduction in surface area. The present article reviews diverse procedures for obtaining porous alumina with high specific surface area, including methods and strategies for preparing high surface alpha-alumina. Within this framework, the paper analyzes the results obtained through bioreplica of lignocellulosic materials. This technology allows preparing aluminas with the complex structural hierarchy of the lignocellulosic templates.

November, 2013 | DOI: 10.3989/cyv.322013

Title: Direct mechanosynthesis of pure BiFeO3 perovskite nanoparticles: reaction mechanism
Author(s): Perejon, A; Murafa, N; Sanchez-Jimenez, PE; Criado, JM; Subrt, J; Dianez, MJ; Perez-Maqueda, LA
Source: Journal of Materials Chemistry C, 1 (2013) 3551-3562

abstract | fulltext

In this work, a mechanochemical procedure is proposed as a simple and fast method to synthesize the pure BiFeO3 perovskite phase as a nanostructured material without the need for purification treatments, while the mechanochemical reaction mechanism has been investigated and correlated with that of the conventional solid-state reaction. Thus, different milling conditions have been used as a tool for tailoring the crystallite size of the resulting BiFeO3 nanoparticles. The materials prepared by the mechanochemical reaction could be annealed or sintered without the formation of undesirable phases. Both the ferroelectric and ferromagnetic transitions were observed by DSC. Finally, the dielectric constants of the prepared material at different frequencies as a function of the temperature have been measured, showing that the material is clearly an isolator below 200 °C, characteristic of a high quality BiFeO3 material.

June, 2013 | DOI: 10.1039/C3TC30446A

Title: Preparation of Titanium Oxide/Silicon Oxide (TiO2/SiO2) systems through the solvothermal method for applications in photocatalysis
Author(s): Galeano, L.; Navío, J.A.; Restrepo, G.M.; Marín, J.M.
Source: Información Tecnológica, 24 (2013) 81-92

abstract | fulltext

Sistemas Óxido de Titanio/Óxido de Silicio (TiO2/SiO2) fueron obtenidos por anclaje de TiO2 en SiO2. El fotocatalizador TiO2 se obtuvo por alcohólisis del TiCl4 con 2-propanol y posterior cristalización a presión autógena a 200 °C, excluyendo etapas de calcinación a altas temperaturas. Se emplearon diferentes relaciones SiO2/TiCl4 para determinar su influencia en la estabilidad, propiedades y fotoactividad de los sistemas TiO2/SiO2. La actividad fotocatalítica fue evaluada por la fotodegradación de metanol en fase gaseosa. El TiO2 cristalizó como fase anatasa o como una mezcla rutilo/anatasa, dependiendo por la relación SiO2/TiCl4 inicial. Los resultados muestran que se producen materiales compuestos con alta cristalinidad del TiO2. Se encontró también que hay una fuerte relación entre la actividad fotocatalítica con las propiedades fisicoquímicas y de estas con las composiciones iniciales de síntesis.

December, 2013 | DOI: 10.4067/S0718-07642013000500010

2012


Title: Advanced nanoarchitectures for solar photocatalytic applications
Author(s): Kubacka, A; Fernandez-Garcia, M; Colon, G
Source: Chemical Reviews, 112 (2012) 1555-1614

abstract | fulltext

Advanced nanostructured materials that demonstrate useful activity under solar excitation in fields concerned with the elimination of pollutants, partial oxidation and the valorization of chemical compounds, water splitting and CO 2 reduction processes, are discussed. Point defects present in nanoparticulated anatase present both 5-fold- and 6-fold-coordinated titanium atoms, as well as 2-fold- and 3-fold-coordinated oxygens. The requirement of using sunlight as the excitation source for the degradation reaction demands, as a principal requirement, the modification of the electronic characteristics of a UV absorber system such as anatase-TiO 2. Some reports also indicate the need for large doping concentrations for N-doping in specific cases where notable changes in the valence band onset are subsequently observed. The effect of cetyltrimethylammonium bromide (CTAB) on the crystallization is reported by Yin et al. They showed that the presence of CTAB induces the appearance of BiOBr during the synthesis at 80°C using an aqueous method.

March, 2012 | DOI: 10.1021/cr100454n

Title: Collective osmotic shock in ordered materials
Author(s): Paul Zavala-Rivera, Kevin Channon, Vincent Nguyen, Easan Sivaniah, Dinesh Kabra, Richard H. Friend, S. K. Nataraj, Shaheen A. Al-Muhtaseb, Alexander Hexemer, Mauricio E. Calvo & Hernan Miguez
Source: Nature Materials, 11 (2012) 53–57

abstract | fulltext

Osmotic shock in a vesicle or cell is the stress build-up and subsequent rupture of the phospholipid membrane that occurs when a relatively high concentration of salt is unable to cross the membrane and instead an inflow of water alleviates the salt concentration gradient. This is a well-known failure mechanism for cells and vesicles (for example, hypotonic shock) and metal alloys (for example, hydrogen embrittlement). We propose the concept of collective osmotic shock, whereby a coordinated explosive fracture resulting from multiplexing the singular effects of osmotic shock at discrete sites within an ordered material results in regular bicontinuous structures. The concept is demonstrated here using self-assembled block copolymer micelles, yet it is applicable to organized heterogeneous materials where a minority component can be selectively degraded and solvated whilst ensconced in a matrix capable of plastic deformation. We discuss the application of these self-supported, perforated multilayer materials in photonics, nanofiltration and optoelectronics.

January, 2012 | DOI: 10.1038/nmat3179

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