CL study of blue and UV emissions in ß-Ga_2O_3 nanowires grown by thermal evaporation of GaN

We report a cathodoluminescence (CL) study of ß-Ga_2O_3 nanowires grown by thermal evaporation of GaN on Si(100) and Au/Si(00) substrates. Condensation and subsequent oxidation of metallic Ga is suggested as the growth mechanism of ß-Ga_2O_3 nanowires. The ß-Ga_2O_3 nanowires grown on Si(100) show multiple bends or undulations, together with a strong UV emission at 3.31 eV and a weak blue emission centered at 2.8 eV as a band component. The ß-Ga_2O_3 nanowires grown on Au/Si(100) substrates recorded a lower CL intensity of a well-defined blue emission of 2.8 eV. A thermal treatment on these samples produced an increase of the UV emission and quenching of the blue band. Thermal annealing of oxygen vacancies is proposed as the responsible mechanism for the observed behavior of these samples

Gypsum plasterboard deconstruction to recycling Economic Study in Europe

Gypsum plasterboard are widely and increasingly used within the construction sector, as partitions, lining of walls, ceiling or flooring systems, representing consequently the largest proportion of the recyclable gypsum waste arisen nowadays in Europe. This paper studies the reverse logistics processes taking place in the End-of-Life (EoL) phase of the recyclable gypsum plasterboard, by analysing and discussing the existing business model for the distinct gypsum waste routes, either deconstruction or demolition, based on economic parameters and assumptions from a set of case studies where best deconstruction practices have been implemented. This analysis has been developed in the framework of the European Life+ GtoG Project ENV/BE/001039: ?From Production to Recycling, a Circular Economy for the European Gypsum Industry with the Demolition and Recycling Industry?. The study highlights the need for an effective deconstruction process to optimize the plasterboard waste recycling, as well as the impact that taxes charged to the disposal of construction and demolition waste have on the economics from deconstruction to recycling. Trabajo publicado en las Actas del Décimoquinto Congreso SGEM, Área "Energy and Clean Technologies", "Subject Area: Energy & Fuels; Geology; Nuclear Science & Technology". Indexado por ISI Web of Knowledge y Scopus. ISBN: 978-619-7105-38-4. Periodicidad: Anua

Formulación de indicadores para la monitorización del reciclaje en ciclo cerrado de productos de base yeso: deconstrucción, procesado y reincorporación

El establecimiento de un sistema de indicadores se ha configurado en los últimos años como un método simple de evaluación en los procesos de toma de decisiones. Los indicadores son medidas cuantitativas, cualitativas o descriptivas, que permiten simplificar la información disponible acerca de un elemento y/o calidad de un proceso, en una forma relativamente sencilla de utilizar y comprender. De tal manera que su información debe de ser relevante y útil para facilitar las decisiones que serán tomadas sobre la base de sus resultados, con el propósito de optimizar los procesos a medir e identificar cambios o mejoras

Gypsum to gypsum (GtoG): The European Life+ project that aims to transform the gypsum waste market

The GtoG project is working for creating a recycling culture of gypsum products, changing the way this waste is usually treated in construction, renovation and demolition works, with the aim of achieving higher gypsum recycling rates in Europe and promoting selective deconstruction practices. For this purpose and under the leadership of Eurogypsum (the European Plaster and Plasterboard Manufacturers Association) five demolition companies, one demolition consultant, two gypsum waste processors, five plasterboard manufacturers and three academic partners, from 7 European countries, work together constituting the project consortium. A preliminary study on current practices was completed in 2013. Subsequently in 2014, a set of demonstration activities on deconstruction, processing of gypsum waste and reincorporation of recycled gypsum were conducted. Finally, during this year 2015, different results have been delivered, such as the European Handbook of best practices for controlled deconstruction of gypsum systems and the Report on best practice indicators for deconstruction, recycling and reincorporation practices. The final results will include an Inventory of best practices and the Roadmap for the future implementation of a sustainable value chain

Gypsum recycling best practice indicators

Since January 2013, the Life+ GtoG project is working for transforming the gypsum waste market. The aim is to achieve higher gypsum recycling rates in Europe and to promote best practices in deconstruction, recycling and reincorporation processes. This paper focuses on the Best Practice Indicators (BPIs) for gypsum recycling. To this end, a set of monitoring parameters have been defined and combined in the form of Key Performance Indicators (KPIs) that have been tested by the three gypsum recyclers participating in the project. As a result, a group of BPIs has been obtained, which can be used to recognize and encourage best practices associated to the recycling route, from a technical, environmental, social and economic perspectiv

Trazabilidad y calidad de los residuos de yeso: análisis de casos de estudio

En ciertos países, como es el caso de España, los residuos de yeso provenientes de Residuos de Construcción y Demolición (RCD), son sistemáticamente enviados a vertedero. Sin embargo, este material es completamente reciclable. Es por ello que existen sistemas de reciclaje ya implantados en distintos países europeos, como es el caso de Bélgica, Dinamarca, Finlandia, Francia, Países Bajos, Reino Unido y Suecia. Forman parte de los residuos de yeso reciclables la Placa de Yeso Laminado (PYL), los bloques de yeso y las placas de escayola

Gypsum end-of-life Best Practice Indicators

The use of indicators has become in recent years as a reliable method of evaluation for the decision-making processes [1]. Indicators give quantitative, qualitative or descriptive information about an item and or process [2] , to ease the decisions that will be taken on the basis of their results, in order to optimize the processes that are being measured identifying changes and improvements [3].This study presents a set of Best Practice Indicators (BPIs) aiming to increase the amount of gypsum waste capable of being recycled, as well as to maximize the quality and percentage of recycled gypsum that can be reincorporated in the manufacturing process. Thus, the practices implemented through the whole value chain of gypsum plasterboard have been assessed. That is to say, from the deconstruction dismantling, through the gypsum waste processing, to the resulting recycled gypsum reincorporation into the manufacturing process. Key Performance Indicators (KPIs) are formulated and used to monitor and compare the five pilot projects conducted in the framework of the Life+ GtoG Project “ From Production to Recycling, a Circular Economy for the European Gypsum Industry with the Demolition and Recycling Industry”

Defining best practices indicators for deconstruction of gypsum based products towards an effective closed-loop

Whereas building demolition is synonym of destruction, resulting on what is usually known as debris, selective demolition or deconstruction devotes special attention to cause minimal damage on materials through on-site waste segregation, therefore increasing the re-use or recycling options. Consequently, segregation becomes essential for effectively close the loop of certain building materials, as for the case of gypsum waste. Aiming to define the best practices indicators for assessing the deconstruction of gypsum based products, five pilot projects in four European countries (Belgium, France, Germany and the United Kingdom) have been monitored through a set of economic, environmental, social and technical parameters. These parameters have been combined in resulting indicators that enable to assess different aspects compared to demolition practices, such as the effectiveness of the deconstruction and segregation processes, waste traceability, labour time, costs and the environmental impacts targeted. The differences arising in each country have also been underlined. The study has been conducted within the framework of the Life+ GtoG project, which from January 2013 is working for transforming the gypsum waste market, with the aim of achieving higher gypsum recycling rates and promoting deconstruction practices in Europe

Forest decline evaluation in Antarctic Beech Forests (Nothofagus antarctica) in Chilean Patagonia by using Landsat TM and ETM+

Antarctic beech forests (Nothofagus antarctica (G. Forst.) Oerst.) have shown a major decline process in the past few decades, together with an important lack of specific studies on this type of forest. The aim of this work was to create cartography of the surface of Antarctic beech forests and to evaluate decline levels in the XII Region of Chile. A study area was selected between the cities of Puerto Natales and Punta Arenas (latitudes 50º40’S to 52º40’S) and from latitudes 60º15’W to 74º15’W, where a random stratified sampling was carried out in 68 plots, in which the forest cover, mortality, height, normal diameter and regeneration were measured. Using two Landsat images (1986-2002), the study area was classified in terms of vegetation cover and forest mortality, by means of the normalized vegetation index (NDVI). The forests in this study area are characterized by their high density, and, in over half their surface (27,873 ha) they exhibit some degree of mortality, with 7,585 ha of forest completely affected. The distribution of the mortality in Antarctic beech on the period 1986-2002 showed an improvement on forests condition, which seems to corroborate the hypothesis of a change on perturbation pattern as the major reason for this forest decline process.Los bosques de ñirre (Nothofagus antarctica) han experimentado en las últimas décadas un importante proceso de mortalidad. El objetivo de este trabajo fue elaborar una cartografía de las masas de ñirre en función de la fracción de cabida cubierta del dosel arbóreo y el nivel de mortalidad en la XII Región de Chile. En una zona entre las ciudades de Puerto Natales y Punta Arenas (50º40’ - 52º40’ S y 69º15’ - 74º15’ O) se realizó un muestreo estratificado en 68 parcelas, donde se midieron: fracción de cabida cubierta, mortandad del arbolado, altura, diámetro normal (DAP) y regeneración. Mediante clasificación de dos imágenes Landsat TM (1986) y ETM+ (2002) se estudiaron el estado de las masas de ñirre y la evolución de la mortandad en un periodo de 16 años, utilizando el índice de vegetación normalizado (NDVI). En el año 2002 los bosques de ñirre se caracterizaban por una elevada fracción de cabida cubierta, tallas y diámetros medios, y una escasa regeneración. Más de la mitad de la superficie de estudio (casi 28.000 ha) presentaba algún grado de mortandad del arbolado, con 7.585 ha de bosques totalmente muertos. El patrón de mortandad, por comparación con el estado del arbolado en 1986, indicó una tendencia a mejorar el estado del arbolado en los últimos 16 años, lo cual parece confirmar la hipótesis de que los procesos de mortandad en esta especie no están asociados a un cambio en el patrón climático en la zona, sino más bien a la modificación del régimen de perturbaciones

Herramienta software para optimizar la utilización de sistemas electromagnéticos de prospección geofísica en la Arqueología

[ES] El objeto de esta ponencia es presentar una aplicación informática encaminada a optimizar las lecturas obtenidas con la utilización de un sistema de radar de subsuelo. Esta herramienta software ha sido contrastada mediante su empleo en el Conjunto Arqueológico de Baelo Claudia en Tarifa (estudio del decumanus maximus y localización de la entrada norte de la ciudad) y en prospecciones varias realizadas hasta la fecha por este grupo (localización de fosas para las asociaciones de memoria histórica de Málaga y Cádiz).[EN] This article shows the applicability of ground penetrating radar (GPR) to archaeological investigations, with the aid of a software that allows increasing the resolution of the measurements. This software has been applied for the first time in Baelo Claud in order to obtain information about city´s decumanus and the crossing with cardines minores Furthermore, the developed tools has also been used to locate in Málaga and Puerto Real (Cádiz) common graves where the remains of about 2,600 victims of the Spanish Civil War rest and the repression that came before and after the civil conflict.Guzmán Navarro, F.; Meco Gutiérrez, M.; Heredia Larrubia, J.; Pérez Hidalgo, F. (2010). Herramienta software para optimizar la utilización de sistemas electromagnéticos de prospección geofísica en la Arqueología. Virtual Archaeology Review. 1(1):111-115. https://doi.org/10.4995/var.2010.5130OJS11111511LORENZO, Enrique y HERNÁNDEZ, Mª Carmen. "Prospección geofísica en yacimientos arqueológicos con georadar en España. Dos casos: Numancia y el Paular". Física de la tierra, ISSN 0214-4557, Nº 7, 1995 (Ejemplar dedicado a: Geofísica aplicada) , pags. 193-206.GARCÍA VALIENTE, Mercedes et al. "Prospección geofísica aplicada a la Arqueología. Investigaciones en el circo romano de Mérida", 1997 . Mapping, ISSN 1131-9100, Nº 40, 1997 , pags. 16-20LORENZO, E., 1996. "Prospección Geofísica de Alta Resolución mediante Georadar. Aplicación a Obras Civiles". CEDEXSANJOSÉ BLASCO, J.J. 2002. "Comparación de los métodos geofísicos de prospección eléctrica y magnética para la localización de muros de piedra en un yacimiento arqueológico". Volver, especial abril 2002VEGA PÉREZ, Gracia, "Radar de subsuelo. Evaluación para aplicaciones en arqueología y en patrimonio histórico-artístico". Departamento de Ingeniería del Terreno, Cartográfica y Geofísica. Universidad Politécnica de Cataluña. Julio 2001CAICEDO HORNAZA, Bernardo et al, "Aplicaciones del georadar de subsuelo en obras civiles", 2003. Universidad de los Andes, Revista de Ingeniería, Nº 18, pags 32-4