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Porriño, Spain

Lodeiro P.,University of La Coruna | Lopez-Garcia M.,University of La Coruna | Herrero L.,Centro Tecnologico AIMEN | Barriada J.L.,University of La Coruna | And 4 more authors.
Journal of Food Science | Year: 2012

In this article, a study of the Al(+3) interactions in acidic waters with biomass of different edible seaweeds: brown (Fucus vesiculosus, Saccorhiza polyschides), red (Mastocarpus stellatus, Gelidium sesquipedale, Chondrus crispus), and green (Ulva rigida, Codium tomentosum), has been performed. The influence of both, the initial concentration of metal and the solution pH, on the Al-uptake capacity of the biomass has been analyzed. From preliminary tests, species Fucus vesiculosus and Gelidium sesquipedale have been selected for a more exhaustive analysis. Sorption kinetic studies demonstrated that 60 min are enough to reach equilibrium. The intraparticle diffusion model has been used to describe kinetic data. Equilibrium studies have been carried out at pH values of 1, 2.5, and 4. Langmuir isotherms showed that the best uptake values, obtained at pH 4, were 33 mg/g for F. vesiculosus and 9.2 mg/g for G. sesquipedale. These edible seaweeds have been found particularly effective in binding aluminum metal ions for most of the conditions tested. Physicochemical data reported at these low pH values could be of interest, not only in modeling aluminum-containing antacids-food pharmacokinetic processes produced in the stomach (pH values 1 to 3) but in remediation studies in acidic waters. © 2012 Institute of Food Technologists®. Source

Lodeiro P.,University of La Coruna | Gudina A.,University of La Coruna | Herrero L.,Centro Tecnologico AIMEN | Herrero R.,University of La Coruna | Sastre de Vicente M.E.,University of La Coruna
Journal of Hazardous Materials | Year: 2010

Aluminium removal has been investigated in synthetic and real wastewaters provided by an aluminium surface treatment plant. Marine algae, obtained as beach cast seaweed (a refuse substance) were used as adsorption material. The influence of pH, metal concentration and time for aluminium elimination was studied by use of synthetic solutions. The optimum pH value was 4.0, which provided a maximum adsorption capacity of 22.5mgg-1. The adsorption percentage surpassed 80% in less than 30min of contact time. Real solutions from the industrial unit were fully characterized and tested in two different fixed-bed columns. One column was filled with 27.5g of dried beach cast seaweed. Three cycles of adsorption and two of desorption were carried out. The first cycle (12mgg-1 maximum sorption capacity) was enough to reach the maximum adsorption capacity at 15mLmin-1 flow rate. The second column was packed with 1100g of seaweed and its behaviour was compared to another column filled with activated charcoal, following both the same experimental procedure. Maximum sorption capacity was 14mgg-1 for seaweed, whereas the activated charcoal only reached 1.6mgg-1 (flow rate of 250mLmin-1). © 2010 Elsevier B.V. Source

Iglesias I.,Spanish University for Distance Education (UNED) | Iglesias I.,Centro Tecnologico AIMEN | Sebastian M.A.,Spanish University for Distance Education (UNED) | Ares J.E.,University of Vigo
Procedia Engineering | Year: 2015

Nowadays industrial robots are an appropriate technology for developing flexible and reconfigurable manufacturing systems which contribute to perform automatically operation such as milling, cutting, drilling, grinding, deburring and polishing. Machining robots symbolize a cost-saving and flexible alternative compared to conventional CNC machines which are the restricted working area and produced shape limitations. The improvement of individual elements and development of new devices has caused a perception change about the use of industrial robots to perform machining operations. The approach to this research was to analyze technical barriers of individual components that it was broken-down as well as full improving the system. This document is intended to provide technical constraints, current technology and future potential researches about robotic machining. © 2015 Published by Elsevier Ltd. Source

Lodeiro P.,Leibniz Institute of Marine Science | Lopez-Garcia M.,University of La Coruna | Herrero L.,Centro Tecnologico AIMEN | Barriada J.L.,University of La Coruna | And 5 more authors.
Clean - Soil, Air, Water | Year: 2016

This paper reports a physicochemical study (thermodynamic and kinetic data) describing the ability of Rubus ulmifolius biomass (dead leaves) for metal uptake. The toxicity of aluminum is a major problem for crops in acidic soils and therefore, aluminum has been selected. The results obtained indicate that dead R. ulmifolius leaves uptake up to 10000mg/kg on its surface in less than 60min. This suggests that R. ulmifolius can be an excellent component with adsorbent properties for aquatic environments and in particular for amendments to be used in acidic soils in order to control aluminum levels, thus its toxicity. The results obtained have been critically analyzed and compared with literature on aluminum bioaccumulation. The application of a pseudo-second order kinetic equation, not previously used in toxicity studies, is discussed. Moreover, a good linear correlation between stability constants for Al3+ complexes with several defined ligands and the Langmuir affinity constants obtained from the corresponding adsorption isotherm has been found. Therefore, in addition to its ethno-botanical relevance, applications of R. ulmifolius as a detoxifier for aluminum in a simulated acidic gastrointestinal fluid, as phytostabilization agent in amendments or in natural attenuation cycles or as biomass for wastewater treatment containing aluminum, are suggested. Rubus ulmifolius leaves can act as a potential adsorbent for aluminum removal in relatively acidic environments (pH 2.5-4). A comparative analysis with aluminum bioaccumulation published data allows concluding the utility of the pseudo-second order equation in the interpretation of metabolic uptake of this metal, not previously suggested and with some interest in the interpretation of Al3+ tolerance by plants. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Cioffi F.,CSIC - National Center for Metallurgical Research | Hidalgo J.I.,Complutense University of Madrid | Fernandez R.,CSIC - National Center for Metallurgical Research | Pirling T.,Laue Langevin Institute | And 6 more authors.
Acta Materialia | Year: 2014

Procedures based on equilibrium conditions (stress and bending moment) have been used to obtain an unstressed lattice spacing, d0, as a crucial requirement for calculating the residual stress (RS) profile across a joint conducted on a 10 mm thick plate of age-hardenable AA2024 alloy by friction stir welding (FSW). Two procedures have been used that take advantage of neutron diffraction measurements. First, equilibrium conditions were imposed on sections parallel to the weld so that a constant d0 value corresponding to the base material region could be calculated analytically. Second, balance conditions were imposed on a section transverse to the weld. Then, using the data and a genetic algorithm, suitable d0 values for the different regions of the weld have been found. For several reasons, the comb method has proved to be inappropriate for RS determination in the case of age-hardenable alloys. However, the equilibrium conditions, together with the genetic algorithm, has been shown to be very suitable for determining RS profiles in FSW joints of these alloys, where inherent microstructural variations of d 0 across the weld are expected. © Published by Elsevier Ltd. All rights reserved. Source

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