During fieldwork in a small outcrop of the lower Aptian Margas de Forcall Formation at La Cova del Vidre, hitherto known as the type locality of the anomuran Pagurus avellanedai, new decapod ...crustacean material has been recovered. In this newly recovered lot, two undescribed species of brachyuran have been recognised; there are here described as Rathbunopon tarraconensis n. sp. and Pithonoton lluismariaorum n. sp. In addition, numerous remains of the anomuran P. avellanedai, enable an improvement of the original description of this taxon, and an analysis of associated ammonites from La Cova del Vidre has resulted in precise age calibration for the first time.
Tailings from tungsten mining activities in the vicinity of Barruecopardo (Salamanca) represent high environmental pollution. In this paper we present a study of the use of these wastes as raw ...materials for the manufacture of glass. This procedure aims to contribute to environmental remediation of mining areas through vitrification, a process which offers an alternative for stabilization of hazardous wastes. In addition, the marketing of the obtained product would provide an additional income to the mining areas. The chemical composition of the tailings to be used as raw materials was determined by X-ray fluorescence and their mineralogy by X-ray diffraction. Wastes are of granitic composition enriched in potentially toxic elements. For this study, a representative sample of mining wastes of sandy grain size was used to make the glass. On the basis of its composition, glass was formulated by adding 29.28 mass% of CaCO
3
and 14.03 mass% of Na
2
CO
3
and a green glass was produced. Crystallisation temperatures, obtained by DTA, were 875 and 1022 °C and the melting temperature was 1175 °C. The transition temperature of glass was of 644 °C. The temperatures for the fixed viscosity points, and the working temperatures were obtained. A thermal treatment induced devitrification to produce a glass–ceramic made of nepheline and wollastonite. Leaching tests of the obtained glass confirm its capacity to retain potentially toxic elements.
Free convection is the most often used method in order to reduce solar load gains on a building with double glazed façades (DGFs). However, depending on the climate factors, the thermal performance ...of a DGF may not be satisfactory and extra energy costs are required to obtain suitable comfort conditions inside the building. Forced ventilation systems are a feasible alternative to improve the thermal performance of a DGF in Mediterranean climates where large solar gains are a permanent condition throughout the year. In this paper the feasibility of using diverse forced ventilation methods in DGF is evaluated. In addition, an economical comparison between different mechanical ventilation systems was performed in order to demonstrate the viability of DGF forced ventilation. Moreover, an environmental study was carried out to prove the positive energetic balance on cooling loads between free and forced convection in DGF for Mediterranean climates. For this investigation, a CFD model was used to simulate the thermal conditions in a DGF for the different ventilation systems. Results obtained for heat flux, temperature and reductions in solar load gains were analyzed and applied for the economic and environmental research.
► Nano-hydroxyapatites analogous to the precipitated ones can be obtained by dry mechanosynthesis. ► These hydroxyapatites are calcium deficient and contain HPO
4
2− groups. ► The HPO
4
2− groups are ...present in the ususal apatitic environment and a non-apatitic environment. ► The non-apatitic environment is a consequence of the nano-dimensions of the apatitic crystals.
Dry mechanosynthesis is an efficient technique to synthesise nanocrystalline calcium deficient hydroxyapatites (CDHA). The mechanisms underlying a mechanochemical reaction are different from those triggering a dissolution mediated process, and this can have an effect on the structural features of the product. In this work, a nanocrystalline CDHA with Ca/P molar ratio of 1.5 obtained by means of dry mechanosynthesis of calcium oxide and dicalcium phosphate dihydrate was analysed. Spectroscopic techniques confirmed the presence of hydrogen phosphate (HPO
4
2−) groups and a non-apatitic environment of the phosphate ions and disordered hydroxyl groups due to the nanometric size of the crystals. Lattice parameters of mechanosynthesised CDHA showed a small increase in the
a
lattice parameter (9.4418(20)
Å) and a small decrease in the
c
lattice parameter (6.8745(17)
Å), in agreement with the values reported in the literature for precipitated CDHAs. A prolonged milling resulted in an increase of the crystallinity of the CDHA and its partial decomposition into β-TCP by the loss of OH
− and HPO
4
2− groups.
The effect of the presence of NaCl on the synthesis of Egyptian blue pigment (cuprorivaite, CaCuSi4O10) was studied through experiments in which different amounts of NaCl were introduced in the ...initial mixture of reactants. The solids synthesized were characterized by X-ray Diffraction, Field Emission Scanning Electron Microscopy (FE-SEM) coupled to Energy-Dispersive Spectrometry (EDS) and High Resolution Transmission Electron Microscopy (HR-TEM) coupled to EDS. The main result of the experiments was that Egyptian blue formation was inhibited in the presence of NaCl, actually, almost no cuprorivaite was found in > 10% NaCl experiments and the solids synthesized in NaCl were always green instead of the characteristic blue of the Egyptian blue pigment. The solids synthesized in the presence of NaCl, a mixture of wollastonite (CaSiO3) and a Cu-rich amorphous phase, probably corresponded to the composition of the pigment known as Egyptian green. Considering the usual presence of NaCl on some of the raw materials used for the pigment fabrication, Egyptian artisans had to be very careful on selecting the reactants for the fabrication of the pigment (quartz would be much more suitable than Egyptian sand, and ash plants than natron) or they incorporated a process of purification of the reactants in order to eliminate chlorides prior to the synthesis.
This research study aims to design, apply and optimize a new mechanism that improves curved façades design and construction processes. In this sense, this investigation has the objective of designing ...an optimization algorithm that: a) is capable of optimizing complex geometric curtain wall paneling so that resulting panels are standardized; b) has a responsive feedback system that visualizes the standardization process and enables users to intervene in this process, permitting an intuitive conceptual design; c) permits the introduction of BIM to the panels and d) is based on broad application strategies so that is a tool applicable as a general working strategy.
The new algorithm has been designed combining physics simulations that act on a conventional CAD system with a polygonal comparative mathematical algorithm. Then it has been applied to Mias Architects’ honorable mention proposal for the contest designed for the future Passenger Service Centre at the Kinmen Port in Taiwan. Finally, this application has been compared to the application of two similar existing software tools analyzing numerous parameters such as mesh density, previous programming time, mesh definition and optimization time, panels’ standardization time, maximum deviation, molds savings and standardization error margin among others.
The new algorithm stands out because is based on glass production and construction information modeling, permits users to standardize paneling if extra time is dedicated to do so and allows users a detailed edition of the mesh. This research project concludes that the investigation has accomplished the initial objectives and the new algorithm is a useful mechanism for conceptual design processes because of their user-friendly environment and their capacity to incorporate glass construction technical knowledge, which overcomes the existing tools.
Due to the current problems related to the generation of diverse wastes and the extraction of nonrenewable materials to be used in the construction sector, the alternative use of waste glass could be ...a sustainable option with environmental and economic benefits, in case of being feasible its use as a replacement of the usual aggregates to manufacture recycled mortars. In this research, one presents a study of the fresh-state properties of the mortars containing 15, 30, 60, and 100% recycled glass aggregates as a replacement for the usual aggregate, providing the experimental results of consistency, density, and air content. Using the experimental results, and by means of a numerical and statistical analysis of these, a diagram of triple interaction that allows us to unify the behavior of the studied properties is constituted; making feasible with this, the prediction of the behavior of these properties with respect to variables as their ratio water/cement, aggregate/cement, and different percentages of replacement of aggregates.
Malgrat les disposicions municipals medievals sobre la prohibició d’installar forns de vidre dins les ciutats, alguns establiments van estar actius durant un temps considerable. La ciutat de ...Barcelona n’és un clar exemple. El present article se centra en les dades documentals trobades en els arxius barcelonins. A la ciutat de Barcelona, el forn de vidre de Viladalls va funcionar des de les primeries del segle XIV fins a finals del XV. Altres forns de vidre van néixer a l’entorn de la ciutat o vinculats a mestres vidriers procedents d’aquesta. És el cas dels forns de Mallorca (1352), Badalona (1360), St. Pere de Bigues (1407-1513), St. Vicenç de Vallromanes (1429-84) i Montcada (1486- 89). Al segle XV, un nou forn de vidre, situat al Pla d’en Llull, tingué l’exclusivitat en la producció de vidre a Barcelona, situació que es va mantenir fins a mitjan segle XVI.
Manufacturing of glass from tin mining tailings in Bolivia Tailings from mining activities in Bolivia represent an environmental problem. In the vicinity of the tin mines of Llallagua,Potosí ...department, there are large dumps and tailings. We present a study of the use of these wastes as raw materials for the manufacture of glass. This procedure aims to contribute to environmental remediation of mining areas through the vitrification, a process which offers an alternative for stabilization of hazardous waste. In addition, the marketing of the obtained product would provide an additional income to the mining areas. For this study three samples of mining waste, with grain size between sand and silt, were used. The chemical composition of these raw materials, determined by X-ray fluorescence, is granitic, with high contents of heavy metals. On the basis of its composition, glass were made from silica glass by adding CaCO3 and Na2CO3. The thermal cycle has been determined from TDA. Tg values of glass range from 626º to 709 °C. Leaching tests of the obtained glasses confirm their capacity to retain heavy metals.
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