Hydrodynamic Modelling of An Oscillating Wave Surge Converter Including Power Take-Off

To estimate the response of wave energy converters to different sea environments accurately is an ongoing challenge for researchers and industry, considering that there has to be a balance between guaranteeing their integrity whilst extracting the wave energy efficiently. For oscillating wave surge converters, the incident wave field is changed due to the pitching motion of the flap structure. A key component influencing this motion response is the Power Take-Off system used. Based on OpenFOAM, this paper includes the Power Take-off to establish a realistic model to simulate the operation of a three-dimensional oscillating wave surge converter by solving Reynolds Averaged Navier-Stokes equations. It examines the relationship between incident waves and the perturbed fluid field near the flap, which is of great importance when performing in arrays as neighbouring devices may influence each other. Furthermore, it investigates the influence of different control strategy systems (active and passive) in the energy extracted from regular waves related to the performance of the device. This system is estimated for each wave frequency considered and the results show the efficiency of the energy extracted from the waves is related to high amplitude pitching motions of the device in short periods of time

Pesticide residues and transformation products in groundwater from a Spanish agricultural region on the Mediterranean Coast

An overview is given on the presence and changes over time of pesticide residues in groundwater from the Valencia region, one of the most important citrus cultivation sites of southern Europe. A multiresidue LC-MS/MS method was applied for the screening of around 50 pesticides in 75 water samples collected during 2000. The herbicides simazine, terbuthylazine, bromacil, terbumeton, and diuron were the most frequently detected compounds. On the basis of compounds detected in these samples, another method that focused on 30 herbicides and relevant transformation products (TPs) was developed and applied to around 80 water samples collected during 2003. Simazine was the most frequently found compound followed by several triazine metabolites. Data for this paper show the vulnerability of groundwater in this area to herbicide applications and illustrate the importance of including pesticide TPs in environmental monitoring programmes, as four out of the five compounds most frequently detected were pesticide TP

Aprendizaje basado en proyectos (PBL) aplicado a la docencia de sistemas tecnológicos de última generación

El planteamiento general de la docencia de asignaturas cuyo contenido es eminentemente tecnológico, presenta el reto del constante y rápido cambio asociado a los avances en desarrollo tecnológico. Dentro de este contexto, se plantea emplear un método basado en la generación de herramientas que permitan un seguimiento autónomo de los cambios frente a opciones más descriptivas del estado actual de los sistemas estudiados. Sobre esta base, se estudia la idoneidad de un contexto basado en el desarrollo de proyectos que, si bien tienen necesariamente que abordar una temática particular, supone una forma a priori interesante de generar las habilidades necesarias para el aprendizaje autónomo y continuado

Stellar populations of galaxies in the ALHAMBRA survey up to z∼1z \sim 1. I. MUFFIT: A Multi-Filter Fitting code for stellar population diagnostics

We present MUFFIT, a new generic code optimized to retrieve the main stellar population parameters of galaxies in photometric multi-filter surveys, and we check its reliability and feasibility with real galaxy data from the ALHAMBRA survey. Making use of an error-weighted $\chi^2$-test, we compare the multi-filter fluxes of galaxies with the synthetic photometry of mixtures of two single stellar populations at different redshifts and extinctions, to provide through a Monte Carlo method the most likely range of stellar population parameters (mainly ages and metallicities), extinctions, redshifts, and stellar masses. To improve the diagnostic reliability, MUFFIT identifies and removes from the analysis those bands that are significantly affected by emission lines. We highlight that the retrieved age-metallicity locus for a sample of $z \le 0.22$ early-type galaxies in ALHAMBRA at different stellar mass bins are in very good agreement with the ones from SDSS spectroscopic diagnostics. Moreover, a one-to-one comparison between the redshifts, ages, metallicities, and stellar masses derived spectroscopically for SDSS and by MUFFIT for ALHAMBRA reveals good qualitative agreements in all the parameters. In addition, and using as input the results from photometric-redshift codes, MUFFIT improves the photometric-redshift accuracy by $\sim 10$-$20\%$, and it also detects nebular emissions in galaxies, providing physical information about their strengths. Our results show the potential of multi-filter galaxy data to conduct reliable stellar population studies with the appropiate analysis techniques, as MUFFIT.Comment: 31 pages, 18 figures, accepted for publication in A&

HRFlexToT: A High Dynamic Range ASIC for Time-of-Flight Positron Emission Tomography

Time-of-Flight positron emission tomography scanners demand fast and efficient photo sensors and scintillators coupled to fast readout electronics. This article presents the high resolution flexible Time-over-Threshold (HRFlexToT), a 16-channel application-specific-integrated circuit for silicon photomultipliers (SiPM) anode readout manufactured using XFAB 0.18- \mu \text{m} CMOS technology. The main features of the HRFlexToT are a linear Time-over-Threshold with an extended dynamic range (10 bits) for energy measurement, low power consumption (≈ 3.5 mW/ch), and an excellent timing response. The experimental measurements show an energy linearity error of ≈ 3% and an energy resolution of about 12% at 511 keV. Single-photon time resolution measurements performed using an Fondazione Bruno Kessler (FBK) SiPM NUV-HD ( 4 \times 4 mm2 pixel, 40- \mu \text{m} cell) and a Hamamatsu SiPM S13360-3050CS are around 142 and 167 ps full width at half maximum (FWHM), respectively. Coincidence time resolution (CTR) measurements with small cross-section pixelated crystals (LSO:Ce,Ca 0.4%, 2 \times 2 \times 5 mm3) coupled to the same Hamamatsu S13360-3050CS and FBK NUV-HD sensors yield a CTR of 117 ps and 119 ps, respectively. Measurements performed with a large cross-section monolithic crystal (LFS crystal measuring 25 \times 25 \times 20 mm3) and a Hamamatsu SiPM array S13361-6050NE-04 show a CTR of 324 ps FWHM after time-walk and time-skew correction

New GOLD classification: Longitudinal data on group assignment

Rationale: Little is known about the longitudinal changes associated with using the 2013 update of the multidimensional GOLD strategy for chronic obstructive pulmonary disease (COPD). Objective: To determine the COPD patient distribution of the new GOLD proposal and evaluate how this classification changes over one year compared with the previous GOLD staging based on spirometry only. Methods: We analyzed data from the CHAIN study, a multicenter observational Spanish cohort of COPD patients who are monitored annually. Categories were defined according to the proposed GOLD: FEV1%, mMRC dyspnea, COPD Assessment Test (CAT), Clinical COPD Questionnaire (CCQ), and exacerbations-hospitalizations. One-year follow-up information was available for all variables except CCQ data. Results: At baseline, 828 stable COPD patients were evaluated. On the basis of mMRC dyspnea versus CAT, the patients were distributed as follows: 38.2% vs. 27.2% in group A, 17.6% vs. 28.3% in group B, 15.8% vs. 12.9% in group C, and 28.4% vs. 31.6% in group D. Information was available for 526 patients at one year: 64.2% of patients remained in the same group but groups C and D show different degrees of variability. The annual progression by group was mainly associated with one-year changes in CAT scores (RR, 1.138; 95%CI: 1.074-1.206) and BODE index values (RR, 2.012; 95%CI: 1.487-2.722). Conclusions: In the new GOLD grading classification, the type of tool used to determine the level of symptoms can substantially alter the group assignment. A change in category after one year was associated with longitudinal changes in the CAT and BODE index

Further progress in the study of epsilon iron oxide in archaeological baked clays

The occurrence of ε-Fe2O3 in archaeological samples that have been subjected to high temperatures is gradually being detected by the use of micrometric structural characterization techniques. This work provides new information by revealing that the ε-Fe2O3 is formed as a response to temperature, the aggregation state and the position within the baked clay with respect to the nearest heat source. In addition, depending mainly on the atmospheric environment, the temperature reached by the combustion structure, the distance from the heating source and the particle aggregation, other iron oxide magnetic phases are produced. In the baked clay studied here, hematite is found over the whole range of samples studied but its magnetic contribution is negligible. Magnetite is observed at the sample surface, probably due to local atmospheric environment closest to the combustion source. Maghemite is found at all depths up to 6 cm below the sample surface. ε-Fe2O3 has a limited distribution, found within 2–3 cm of the sample surface. Furthermore, the viability of this compound as a palaeofield marker has been evaluated in both archaeological and synthetic samples. The results indicate that ε-Fe2O3 is able to register the direction of the magnetic field. Linear palaeointensity plots have been obtained in synthetic samples, although the value of the palaeofield could be, sometimes, overestimated

Señales, sistemas y telecomunicación

En ingeniería de telecomunicación los conceptos relacionados con teoría de la señal son uno de los pilares básicos. Si bien, la teoría no es excesivamente compleja, su asimilación no resulta sencilla. Los métodos empleados para el proceso de optimización de sistemas de refuerzo sonoro suponen una aplicación práctica directa de estos conceptos, con un impacto visual inmediato. Se pretende evaluar el impacto en el proceso de interiorización de los conceptos de teoría de la señal (principalmente respuesta al impulso y función de transferencia) de la aplicación de los procesos de análisis y optimización de sistemas de refuerzo sonoro