Study on the use of MgAl hydrotalcites as solid heterogeneous catalysts for biodiesel production

This paper, reports experimental work on the use of new heterogeneous solid basic catalysts for biodiesel production: double oxides of Mg and Al, produced by calcination, at high temperature, of MgAl lamellar structures, the hydrotalcites (HT). The most suitable catalyst system studied are hydrotalcite Mg:Al 2:1 calcinated at 507 degrees C and 700 degrees C, leading to higher values of FAME also in the second reaction stage. One of the prepared catalysts resulted in 97.1% Fatty acids methyl esters (FAME) in the 1st reaction step, 92.2% FAME in the 2nd reaction step and 34% FAME in the 3rd reaction step. The biodiesel obtained in the transesterification reaction showed composition and quality parameters within the limits specified by the European Standard EN 14214. 2.5% wt catalyst/oil and a molar ratio methanol:oil of 9:1 or 12:1 at 60 -65 degrees C and 4 h of reaction time are the best operating conditions achieved in this study. This study showed the potential of Mg/Al hydrotalcites as heterogeneous catalysts for biodiesel production. (C) 2011 Elsevier Ltd. All rights reserved

Despojos alimentares encontrados em abrigos de polvo comum (Octopus vulgaris) (Mollusca: Cephalopoda) do Faial (Açores) : dados preliminares.

VIII Expedição Científica do Departamento de Biologia – Ilha do Faial - 1993.The prey remains found around the dens of 6 octopus (Octopus vulgaris) were collected during the "Expedition Faial-93" (28 June to 3 July 1993) in "Reserva do Monte da Guia" by SCUBA diving (total of 4 dives). Based on this very preliminary work, the small crabs (Xantho spp.), bivalves (Limaria hians), and ormers (Haliotis tuberculata), seems to be the most important food items in the octopus feeding regime. Drill holes made by the octopus were observed on crab carapaces and chelipeds, but were not found on molluscan shells. The drill holes on the chelipeds or crabs are reported for the first time

On the nature of the (de)coupling of the magnetostructural transition in Er5_5Si4_4

In this report, a successful thermodynamical model was employed to understand the structural transition in Er$_5$Si$_4$, able to explain the decoupling of the magnetic and structural transition. This was achieved by the DFT calculations which were used to determine the energy differences at 0 K, using a LSDA+U approximation. It was found that the M structure as the stable phase at low temperatures as verified experimentally with a $\Delta F_0 = -$0.262 eV. Finally, it was achieved a variation of Seebeck coefficient ($\sim$ 6 $\mu$V) at the structural transition which allow to conclude that the electronic entropy variation is negligible in the transition.Comment: 17 pages, 3 figures, 1 tabl

Low-latency privacy-enabled Context Distribution Architecture

As personal information and context sharing applications gain traction more attention is drawn to the associated privacy issues. These applications address privacy using an unsatisfactory {"}whitelist{"} approach [1] [2], similar to social networks {"}friends{"}. Some of them also link location publishing with user interaction which is also a form of privacy control - the user has to explicitly say where he is. There are a few automatic location based-services (LBS) that track the user [3], but without more adequate privacy protection mechanisms they enable even bigger threats to the user. On previous work, an XMPP-based Context Distribution Architecture was defined [4], more suitable for the distribution of frequently changing context than other systems because it is based on the publish-subscribe pattern. In this paper the authors present an extension to this architecture that allows for the introduction of a complex degree of access control in context distribution. The devised changes enable the system to consider a number of interesting context privacy settings [1] for context distribution control. Also, this control must be enforced in a way that it doesn't interfere with the real-time nature of the distribution process. After describing the enhancements to the architecture, a prototype of the system is presented. Finally, the delivery latency and additional processing introduced by the access control components is estimated by testing it against the existing system

Duas novas ocorrências de Ziphiidae (Cetacea) nos Açores e actualização da lista de espécies de cetáceos

Os arrojamentos ocorridos em 1989, dum zífio, Ziphius cavirostris G. Cuvier, 1823, na ilha de Santa Maria, e duma baleia de bico-de-Gervais, Mesoplodon europaeus (Gervais, 1855) na ilha do Faial, representam os primeiros registos destas espécies paro o Arquipélago dos Açores. As medidas externas dos dois espécimes e a craniometria de M. europaeus são apresentadas. Fornece-se também uma lista actualizada das 22 espécies de cetáceos registados para as águas dos Açores, embora a presença de 3 delas seja actualmente duvidosa.ABSTRACT: Two standings in 1989 of a Cuvier’s Beaked Whale, Ziphius cavirostris G. Cuvier, 1823, on the Island of Santa Maria, and of a Gervais’ Beaked Whale, Mesoplodon europaeus (Gervais, 1855), on the Island of Faial, represent the first records of these species in the Azores archipelago. Body measurements of both specimens and the skull biometry of M. europaeus are presented. An updated checklist or 22 cetaceans recorded from the Azorean waters is also presented, although the presences of 3 of them are actually dubious

Recycling of Reinforced Glass Fibers Waste: Current Status

UID/00667/2020In this paper, a review of the current status and future perspectives for reinforced glass fiber waste is undertaken, as well as an evaluation of the management hierarchy for these end-of-life materials. Waste levels are expected to increase in the coming years, but an improvement of collection routes is still necessary. The recycling processes for these materials are presented. The associated advantages and disadvantages, as well as the corresponding mechanical characteristics, are described. Although mechanical shredding is currently the most used process, there is a potential for thermal processes to be more competitive than others due to the fiber quality after the recycling process. However, the energy requirements of each of the processes are not yet well explained, which compromises the determination of the economic value of the recycled fibers when included in other products, as well as the process feasibility. Nevertheless, the work of some authors that successfully integrated recycled glass fibers into other elements with increased mechanical properties is evaluated. Future recommendations for the recycling of glass fiber and its commercialization are made.publishersversionpublishe

Cephalopod identification keys to Histioteuthidae, Cranchiidae and Octopodiformes of the Azores, with an updated check-list

This work is a combination of unpublished cephalopod identification keys compiled by Malcolm R. Clarke for the Azores region (Central North Atlantic) and a review of the Octopoda of the Azores by João Gonçalves (MSc Thesis 1993, originally written in Portuguese), updated with recent literature. A regional list of cephalopod species of the Azores is provided totaling 83 species, with identification keys for: i) Histioteuthidae, including five species; ii) Cranchiidae, including eleven species; and iii) Octopodiformes, including Vampyroteuthis infernalis Chun, 1903 (Order Vampyromorpha), three cirrate and fourteen incirrate octopuses. Separate keys are given for Octopodiformes species. The revisions are discussed and a more detailed description of Octopoda species is included.Oma – Observatório do Mar dos Açores ; MARE – Centro de Ciências do Mar e do Ambiente ; IMAR – Instituto do Mar ; DOP – Departamento de Oceanografia e Pescas ; Universidade dos Açoresinfo:eu-repo/semantics/publishedVersio

Dificuldades associadas à reabilitação do património construído em taipa no Algarve

A construção em terra no Algarve é muito antiga, tendo sido popularizada durante a ocupação Árabe. Desse período, existem diversas construções militares edificadas em taipa que ainda existem e que constituem um importante património monumental, donde se destacam o Castelo de Paderne e parte das muralhas do Castelo de Silves e da cidade de Faro. Também existe um grande número de construções particulares mais recentes, que também elas constituem um património cultural que importa preservar. As principais debilidades das construções em terra crua e, especificamente das realizadas em taipa, são a ação da água, designadamente proveniente de chuva e, em particular, quando associada ao vento, e os efeitos resultantes da ocorrência dos sismos. Quanto à primeira, é perfeitamente possível adotar disposições construtivas que evitem as respetivas consequências. Em relação à ação das vibrações provocadas pela ocorrência dos sismos, o problema reside na fraca resistência deste material à tração, apresentando um comportamento muito frágil. É neste contexto que a reabilitação da construção em taipa existente no Algarve se torna um grande desafio técnico, atendendo à perigosidade sísmica da região. Neste trabalho é apresentado um levantamento de construções de taipa ainda existentes no Algarve, e é descrito o processo construtivo que foi utilizado. Com vista a identificar as dificuldades que têm que ser superadas de modo a que a reabilitação deste tipo de construções apresente os níveis de segurança que a sociedade atual exige, sem a adulteração do património existente, foi efetuado um conjunto de estudos cujos resultados são apresentados neste trabalho. Foi realizada uma campanha de ensaios laboratoriais para caracterização do comportamento mecânico do material, e foi organizada uma lista das principais anomalias encontradas no património edificado. Com base nesses resultados, foi realizada uma avaliação preliminar do comportamento estrutural não linear das paredes tipicamente realizadas em taipa no Algarve, identificando alguns problemas relacionados com alguns aspetos arquitetónicos e construtivos dos edifícios de habitação, designadamente os relacionados com a colocação do telhado, bem como a existência de portas e janelas nas paredes exteriores das construções, a ligação das paredes à fundação e a ligação entre paredes ortogonais