Munoz M.,University of Zaragoza |
Moreno F.,University of Zaragoza |
Monne C.,University of Zaragoza |
Morea J.,University of Zaragoza |
Terradillos J.,Centro Tecnologico
Renewable Energy | Year: 2011
In this work, biodiesel from waste vegetable oil was used as an additive in low sulphur diesel fuel in automobile engines. The result was a fuel mixture with high lubricating power. According to the lubrication trials, the experimental mixtures complied with lubricity conditions established by European regulations, even when only a small quantity of biodiesel was used. It was also found that the mixtures were compatible with different engine gaskets and engine lubricant. Lastly, bench tests were performed using an automobile engine with mixtures of diesel fuel without conventional lubricant additive and biodiesel. The results showed that engine performance curves were very similar to those obtained with diesel fuel and that contaminating emissions from the engine decreased substantially by including biodiesel in the fuel, except for nitrogen oxides. © 2011 Elsevier Ltd.
Rossi F.,University of Coimbra |
Olabarria C.,University of Vigo |
Incera M.,Centro Tecnologico |
Garrido J.,University of Vigo
Journal of Sea Research | Year: 2010
Native and exotic seaweeds frequently lie on the beach and sustain part of the benthic food web. However, the role of exotic seaweeds as food sources for beach consumers has been poorly studied. We studied the temporal and spatial variability in the trophic significance of the invasive brown seaweed Sargassum muticum on sandy beaches. We measured the stable isotopes (δ13C and δ15N) in the tissues of S. muticum and of invertebrate consumers and estimated the dietary biomass proportion of S. muticum during four sampling dates at two beaches and heights on the shore. Samples were collected from eight pitfall traps placed at a distance of 2 m from each other. Detrital macroalgae and seagrasses were also collected by hand within an area of 30 cm around each pitfall trap. We measured the spatial and temporal variability in the isotope composition of the beach consumers and of S. muticum using different models of analyses of variance. We then calculated the biomass proportion of S. muticum to the animal diet with a two-isotopic mixing model. The invasive alga S. muticum seemed to be one of the main food sources for the amphipod Talitrus saltator and, to a less extent, for the isopod Tylos europaeus. The importance of S. muticum was however temporally variable and decreased during spring (in March and May), probably due to the availability of native macrophytes. The supply of invasive wrack to beach food webs thus deserves more attention if we want to understand their role in influencing food web dynamics. © 2009 Elsevier B.V. All rights reserved.
Carcel J.A.,Polytechnic University of Valencia |
Nogueira R.I.,Embrapa Agroindustria de Alimentos |
Rossello C.,University of the Balearic Islands |
Mariano E.S.,Polytechnic University of Valencia |
And 2 more authors.
Defect and Diffusion Forum | Year: 2010
Naik model, high intensity ultrasound, mass transfer, bioactive compounds, The olive crop has a great importance in the economy of Spain. Every year during the pruning of the olive trees a significant quantity of leaves are cut and discarded. It is known that these leaves constitute a source of antioxidant compounds and its processing would provide an added value to this raw material. Antioxidant compounds may be damaged when drying, the previous process to extraction. Thus, the goal of this work was to study the influence of the high intensity ultrasound applied during the drying of olive leaves on the kinetic of extraction of antioxidants compounds. From the parameters identified from Naik model, it can be concluded that the application of high intensity ultrasound during drying reduced the antioxidant activity of extracts at the equilibrium but increased the initial extraction kinetic compared to conventional hot air drying. This last aspect could have high interest to the antioxidant extraction from an industrial scale point of view. © (2010) Trans Tech Publications.
Da Silva Jr. W.M.,Centro Tecnologico |
De Mello J.D.B.,Laboratorio Of Tribologia E Materiais
Proceedings - International Brazilian Conference on Tribology | Year: 2010
Recent studies state that the wear mechanisms of material removal are connected to the movement of the active particles present at the wear interface. According to tribological conditions, active wear particles slide or roll between surfaces. Particles rolling result in multiple indentations on wear surface. This work presents four experimental methods to evaluate the effect of indentations superimposition in the prevailing wear mechanism. A new device was especially developed to reproduce the abrasive particle interaction. In order to study the effect of superimposition on wear mechanism, series of indentations were created on M2 tool steel sample surfaces by varying the distance between indentations. Analyses were carried out using laser interferometry and SEM. Only one of the methods described in this work presented consistent results that permit the identification of the superimposition degree range, in which wear was observed. Tests showed that a small degree of superimposition results in plastic deformations of the surface. Degrees of superimposition of indentations higher than 50% resulted in mass loss. This method also allows the mapping of the average depth of indentations in function of superimposition degree and normal load of interactions.
Maia J.R.,Federal University of Ceara |
Lima Jr. J.A.,Federal University of Ceara |
Freire P.T.C.,Federal University of Ceara |
Mendes Filho J.,Federal University of Ceara |
And 5 more authors.
Journal of Molecular Structure | Year: 2013
In this work the Fourier transform infrared and the Raman spectra of bis(L-hisidinato)nickel(II) monohydrate were recorded at room temperature. Optimized geometry and vibrational frequencies were obtained by means of Density Functional Theory (DFT). Experimental and theoretical vibrational spectra were compared and a complete analysis of the modes was done in terms of the Potential Energy Distribution (PED). © 2013 Elsevier B.V. All rights reserved.