Impact of climate change on wave energy resource: the case of Menorca (Spain)

The aim of this paper was to analyse how changes in wave patterns, due to the effect of climate change, can affect wave energy power and yield around Menorca (NW Mediterranean Sea). The present and future wave energy conditions were derived from recently developed high-resolution wave projections in the NW Mediterranean. These wave projections were forced by surface wind fields obtained, respectively, by 5 different combinations of global and regional circulation models (GCMs and RCMs) for the A1B scenario. The results showed that the projected future spatial and directional distributions of wave energy are very similar to those of the present conditions. The multi-model ensemble average illustrated a slight general decrease in the annual and seasonal wave power (except for summer). However, the inter-model variability is large since two models showed opposite trends to the other 3 in most cases. Such inter-model variability is lower(higher) for winter(autumn). Another result is the reduction of the temporal variability in the future, considering both the multi-model mean and each single model projection. Such a decrease is consistent with the future seasonal redistribution of energy throughout the year. This would entail an increase in the efficiency of wave energy converters deployed in this area due to the more regular temporal distribution of the energy.Peer ReviewedPostprint (author's final draft

Distribució de la 5-cloro-7-iodo-8-hidroxiquiloneïna i del seu complex de magnesi en el sistema aigua cloroform. Determinació fluorimètrica de magnesi

En aquest treball hom estudia la distribució de la 5-cloro-7-iodo-8-hidroxiquinoleïna (ClIOxH) i del seu complex de Mg(II) en el sistema aigua-cloroform. Han estat obtinguts els valors següents per a les constants relacionades amb aquests processos: log KDR = 4.60 ± 0.04; pK1 = 2.88 ± 0.10: pK2 = 7.67 ± 0.07 i log Kex = - 14.25. L'estequiometria del complex extret es Mg(ClIOx)2 Les principals característiques del mètode fluorimètric proposat són: λ ex= 405 nm i λ em = 528 nm, pH = 10.0 - 10.5; la intensitat de fluorescència es manté constant durant 2 hores; el mètode es lineal fins a 1.01 μg/ml, i el límit de detecció és 0.009 μg/ ml. Ha estat estudiat l'efecte d'alguns ions sobre la intensitat de fluorescència de l'extracte.The distribution equilibria of 5-chloro-7-iodo-8-hydroxyquinoline (ClIOxH) and of its Mg(II) complex in the water-chloroform system have been studied. The following values of the equilibrium constants involved in these processes have been obtained: log KDR= 4.60 ± 0.04; pK1 = 2.88 ± 0.10; pK2 = 7.67 ± 0.07 and log Kex = -14.25. The stechiometry of the extracted complex is Mg(ClIOx) 2. The main characteristics of the fluorimetric method proposed are: λ ex= 405 nm and λ em = 528 nm, pH = 10.0 - 10.5; the fluorescence remains stable for 2 hr.; the calibration graph is linear up to 1.01 μg/ml and the detection limit is 0.009 ug/ml. The effect of several ions on the fluorescence of the extratcs has been investigated

Hopf bifurcation for the hydrogen atom in a circularly polarized microwave field

We consider the Rydberg electron in a circularly polarized microwave field, whose dynamics is described by a Hamiltonian depending on one parameter, K¿>¿0. The corresponding Hamiltonian system of ODE has two equilibrium points L1 (unstable for all K and energy value h(L1)) and L2 (a center for K¿¿Kcrit, with energy value h(L2)). We study the Hamiltonian-Hopf bifurcation phenomena that take place for K close to Kcrit around L2. First, a local analysis based on the computation of the integrable normal form up to a finite order is carried out and the steps for the computation of this (resonant) normal form are explained in a constructive manner. The analysis of the normal form obtained allows: to claim the type of the Hopf bifurcation –supercritical–; to study the local behavior of the electron in a neighborhood of the equilibrium L2 for the original non integrable Hamiltonian (as a perturbative approach from the integrable normal form); to obtain (approximations for) the parametrizations of the relevant invariant objects that take place due to the bifurcation (periodic orbits and invariant manifolds of L2). We compute numerically such objects and analyse not only the local picture of the dynamics close to L2, but also a global description of the dynamics and the effect of the Hopf bifurcation as well as other objects that organize the dynamics are discussed. We conclude that, for K close to Kcrit and the energy level h(L2), the Hopf bifurcation has essentially no effect on the dynamics from a physical point of view. However, for bigger values of K¿>¿Kcrit, the Hopf bifurcation has a dramatic effect: different kind of orbits coexist, mostly chaotic. Such orbits provide a ionization mechanism with several passages far from and close to L2 before ionizing. Surprisingly enough, also robust confinement regions (where the electron remains confined for ever), exist in the middle of chaotic areasPeer ReviewedPostprint (published version

Motion near the transition to complex instability: some examples

Complex instability is a generic kind of instability in Hamiltonian systems with three degrees of freedom. In this work, some examples of such instability are shown, together with a numerical analysis of the dynamics close to the transition from stability to comlex instability for a family of periodic orbits

Población microbiana en los fangos activados de una planta depuradora de aguas residuales textiles.

Se ha seguido durante más de tres meses la evolución del número de células viables en dos medios diferentes: TSA (BBL 1 1043) y AE (aguade entrada residual solidificada con agar), en los fangos activados de una planta depuradora piloto aclimatada a tratar un agua residual textil tipo. Se pensaba que la densidad propia de la población del fango daría una estima fiel del rendimiento de depuración en aquellas condiciones. Sin embargo, se comprueba que la densidad de la población de bacterias en los fangos no influye decisivamente en el rendimiento de la depuradora. Se concluye que es necesario profundizar en el estudio de la población de protozoos como grupo con influencia decisiva en el rendimiento del proceso.The evolution of the number of viable cells was followed for more then three months using two different mediums: - TSA (BBL 11.043) - AE (sewage water solidified with agar) in activated sludge from a epuration pilot plant acclimatized for treating standard textile sewage waters. It was thought that the peculiar density of the bacterial population of sludge would show a factual estimated of the epuration performance under those conditions. Not withsthanding, it has been verified that the density of the bacterial population sludge does not decisively influence the performance of the epuration plant. This infers that it is necessary to study in depth the protozoa population as a group wich a decisive influence on the performance of the process.L'Evolution du nombre de cellulles viables dans deux milieux de cuiture differents: TSA (BBL 11043) et AE (eau residuarie solidifiee avec de l'agar), a éte suivie pendant trois mois, dans les boues activées d'une plante d'épuration adapté a un effluent textile standard. On pensait que la densite de la population bacterienne de la boue donnerait une estimation du rendement de l'épuration dans ces conditions. Cependant, la densite de la population des bacteries dans les boues n'a pas d'influence decisive dans le vendement de la plante d'epuration. La conclusion est qu'il est necessaire d'approfondir sur l'étude de la population des protozoaires comme un groupe qui a une influence tres importante dans le rendement du proces.Peer Reviewe

Biodegradabilidad, toxicidad y acumulación del colorante acido azul omegacromo en la trucha arco iris "Salmo Gairdneri".

Se estudia el impacto ambiental producido por el colorante de tintura Azul Omegocromo B. Se determina: su biodegradabilidad en condiciones aerobias, su toxicidad en la trucha arco iris "Salmo gairdnen" en condiciones agudas y subagudas y la acumulación en vanos órganos (branquias, hígado, pancreas y músculo) para las ditintas dosis en el tratamiento subagudo.The environmental impact caused by the Omegachrome Blue B dye is studied. The following parameters have been determinated: its biodegradability under aerobic conditions, its toxiaty in the rainbow trout "Salmo gairdneri" under acute and subacute conditions and the accumulation in come organs (gill, liver pancreas and muscle) for different doses in the subacute treatment.On étudie l'impact ambientale produit par le colorant Bleu Omegachrome B. On determine la biodegradabilite en moyen aerobie, la toxicité sur la truite arcen.ciel "Salmo gairdnen" aigüe et subagüe et l'accumulation dans divers organes (branchies, foie, pancreas et muscle) a plusieures doses a l'essai subaigu.Peer Reviewe

Exploring the antioxidant features of polyphenols by spectroscopic and electrochemical methods

This paper evaluates the antioxidant ability of polyphenols as a function of their chemical structures. Several common food indexes including Folin-Ciocalteau (FC), ferric reducing antioxidant power (FRAP) and trolox equivalent antioxidant capacity (TEAC) assays were applied to selected polyphenols that di er in the number and position of hydroxyl groups. Voltammetric assays with screen-printed carbon electrodes were also recorded in the range of 0.2 to 0.9 V (vs. Ag/AgCl reference electrode) to investigate the oxidation behavior of these substances. Poor correlations among assays were obtained, meaning that the behavior of each compound varies in response to the di erent methods. However, we undertook a comprehensive study based on principal component analysis that evidenced clear patterns relating the structures of several compounds and their antioxidant activities

Extracció amb CO2 supercrític: II. Aplicacions a la indústria alimentària

La tècnica d'extracció amb fluids supercrítics (ESC) a la indústria alimentària i amb CO2 com a dissolvent està plenament establerta, sobretot en processos de descafeïnat de cafè i te, extracció de llúpol, extracció d'aromes i sabors d'espècies i herbes aromàtiques i separació del colesterol de la mantega, la carn i el rovell de l'ou. L'ESC és una tècnica de separació respectuosa amb el medi ambient i pot substituir progressivament molts dels processos d'extracció realitzats amb dissolvents orgànics, que són en general potencialment tòxics, inflamables i tenen un preu elevat. L'ESC presenta un futur encoratjador en processos d'extracció i separació de principis actius en productes naturals pels seus avantatges. El present article correspon a un resum adaptat del treball complet que ha estat publicat en una revisió al Food Science and Technology International (FSTI) (octubre 2002) i constitueix el capítol 5 del llibre sobre tecnologies emergents (gener 2003).The extraction technique with supercritical fluids at food industries, and with CO2 as a solvent, is fully established, mainly in processes for caffeine extraction in coffee and tea, hops extraction, flavours and fragrances extraction from spices and aromatic herbs, as for cholesterol separation from butter, fats, meat and egg yolk. The SCE is a separation technique that is environmental friendly and can substitute progressively many of the extraction processes that use organic potentially toxic and flammable solvents and have a high cost. SCE shows a pretty good future due to its advantage for extraction and separation processes of active components in natural products. This article corresponds to an adaptation of the original that has been published in a Review at Food Science and Technology International (FSTI) (2002, October) and is the 5th chapter of the book about Emergent Technologies (2003, January)

Analysis of non-steroidal anti-inflammatory drugs in milk using QuEChERS and liquid chromatography coupled to mass spectrometry: triple quadrupole versus Q-Orbitrap mass analyzers

We developed a Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method for the high throughput determination of 10 non-steroidal anti-inflammatory drugs (NSAIDs) in milk samples using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) with a triple quadrupole (QqQ) instrument and an electrospray ionization (ESI) source. The new extraction procedure is highly efficient, and we obtained absolute recoveries in the range 78.1-97.1 % for the extraction and clean-up steps. Chromatographic separation is performed in the gradient mode with a biphenyl column and acidic mobile phases consisting of water and acetonitrile containing formic acid. The chromatographic run time was about 12 min, and NSAID peaks showed a good symmetry factor. For MS/MS detection, we used multiple reaction monitoring (MRM) mode, using ESI in both positive and negative modes. Our method has been validated in compliance with the European Commission Decision 657/2002/EC, and we obtained very satisfactory results in inter-laboratory testing. Furthermore, we explored the use of a hybrid high resolution mass spectrometer, combining a quadrupole and an Orbitrap mass analyzer, for high resolution (HR) MS/MS detection of NSAIDs. We achieved lower NSAID quantification limits with Q-Orbitrap high resolution mass spectrometry (HRMS/MS) detection than those achieved with the QqQ instrument; however, its main feature is its very high selectivity, which makes HRMS/MS particularly suitable for confirmatory analysis