Apetrei C.,University of Galati
Food Research International | Year: 2012
A new methodology for the analysis of extra virgin olive oils has been developed. The method employs voltammetric electrodes based on polypyrrole (Ppy) used as sensing units of a sensory system. The array of sensors has been exposed to emulsions of extra virgin olive oils. The features observed in the cyclic voltammograms reflect the redox properties of the electroactive compounds (mainly antioxidants), which are present in the emulsions of extra virgin olive oils. Each sensor shows a characteristic electrochemical signal when exposed to the studied emulsions, providing a high degree of cross-selectivity. The principal component analysis (PCA) and the partial least squares discriminant analysis (PLS-DA) of the obtained signals have allowed the discrimination of the six extra virgin olive oils tested according to their degree of bitterness. Good correlations between electrochemical responses and the physico-chemical and sensorial characteristics of the virgin olive oils under study have been found. © 2012 Elsevier Ltd.
Rusu L.,University of Galati
Journal of Environmental Engineering and Landscape Management | Year: 2010
The last decades continuously increasing of the economical activities in the coastal environment of the Black Sea is obviously leading to the enhancement of the pollution risks due to accidental oil spillages. Starting from the fact that most accidents were generated by an inadequate forecast of the wave conditions, the aim of the present work is to develop a methodology based on spectral phase-averaging wave models able to predict the wave propagation in the coastal environment. The wave induced currents that may be a key factor in driving the pollution are also assessed. This implies both the Stokes drift and the wave induced nearshore currents. The surface streaming effect due to the molecular viscosity was also accounted for. In the nearshore, close to the surf zone, the pollution is usually spread along the coast due to the longshore currents. In this connection, the results of a simple but effective model system called ISSM are also presented. As an alternative simulations with the SHORECIRC model system are also performed. Finally, as a case study, the propagation of the pollution towards the Romanian coast generated by a hypothetic accident at the Gloria drilling platform was assessed.
Rusu E.,University of Galati
Journal of Marine Science and Technology | Year: 2010
The target of the present study is the entrance to the Danube Delta in the Black Sea. The wave conditions in this coastal sector are usually significant from an energetic point of view and the relatively strong currents induced there by the outflow from the Danube lead to interactions between waves and currents. This process modifies considerably both the magnitude and direction waves, affecting also coastal navigation and sediment transport patterns. In order to assess the effects of the wave-current interactions, the simulating waves nearshore (SWAN) model was considered for developing a multilevel wave prediction system. Validations against measured data were carried out for each computational level. Five case studies corresponding to the most relevant patterns of the environmental matrix were analyzed. Finally, in order to assess the current effect for a longer timescale, an analysis concerning the variation of the main wave parameters was performed for a 3-month period considering some reference points. The results show that the currents produce considerable changes in the wave field, especially as regards the significant wave heights, mean wave directions and wavelengths. The Benjamin-Feir index was also estimated. The analysis of the variation induced by the current over this spectral shape parameter indicates that, in certain conditions, in the target area the wave heights cannot be considered Rayleigh distributed and freak waves may also occur. © 2009 JASNAOE.
Rusu E.,University of Galati
Energies | Year: 2014
The main objective of the present work was to assess and compare the wave power resources in various offshore and nearshore areas. From this perspective, three different groups of coastal environments were considered: the western Iberian nearshore, islands and an enclosed environment with sea waves, respectively. Some of the most representative existent wave converters were evaluated in the analysis and a second objective was to compare their performances at the considered locations, and in this way to determine which is better suited for potential commercial exploitation. In order to estimate the electric power production expected in a certain location, the bivariate distributions of the occurrences corresponding to the sea states, defined by the significant wave height and the energy period, were constructed in each coastal area. The wave data were provided by hindcast studies performed with numerical wave models or based on measurements. The transformation efficiency of the wave energy into electricity is evaluated via the load factor and also through the capture width, defined as the ratio between the electric power estimated to be produced by each specific wave energy converters (WEC) and the expected wave power corresponding to the location considered. Finally, by evaluating these two different indicators, comparisons of the performances of three WEC types (Aqua Buoy, Pelamis and Wave Dragon) in the three different groups of coastal environments considered have been also carried out. The work provides valuable information related to the effectiveness of various technologies for the wave energy extraction that would operate in different coastal environments. © 2014 by the authors.
Benea L.,University of Galati
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2013
A series of Co/CeO2 (25 nm) nanocomposite coating materials by electrodeposition were successfully prepared containing different cerium oxide composition in the cobalt-plating bath. Stainless steel (304L) was used as support material for nanocomposite coatings. The nano-CeO2 is uniformly incorporated into cobalt matrix, and the effect on surface morphologies was identified by scanning electron microscopy with energy-dispersive X-ray analysis. Codeposition of nano-CeO2 particles with cobalt disturbs the regular surface morphology of the cobalt coatings. It should be noted that the as-prepared Co/CeO2 nanocomposite coatings were found to be much superior in corrosion resistance over those of pure cobalt coatings materials based on a series of electrochemical impedance spectroscopy measurements in simulating body fluid solution. With increase in the nano-CeO2 particles concentration in the cobalt electrolyte, it is observed that the corrosion resistance of Co/CeO2 increases. Co/CeO2 nanocomposite coatings have higher polarization resistance as compared with pure cobalt layers in simulating body fluid solution. © 2012 The Minerals, Metals & Materials Society and ASM International.