1,342 research outputs found

    Alcohol consumption among University students in Spain

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    Producción CientíficaAlcohol consumption in 1984 among 2921 students of nine Faculties in the University of Valladolid (Spain) is reported. Alcoholic drinks were frequently consumed, especially by males and during weekends. Per capita consumption was 9.85 l of absolute alcohol/year for males and 4.971 for females. Beer, wine and gin were the favourite drinks. Alcohol consumption was similar in the different faculties and age groups but was to some extent related to age and place of residence in male students. Students' alcohol consumption was not as high as in the general Spanish population, and seems to have been stable during the last 10 years

    Influence of process parameters on the corrosion resistance of corrugated austenitic and duplex stainless steels

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    The main objective of this work is to study the influence of the forming process on two corrugated, lean, duplex stainless steels (DSSs): UNS S32001 and UNS S32304. Both grades have been recently proposed as alternative materials to the austenitic UNS S30403 grade for manufacturing reinforcement bars to be embedded in concrete structures, exposed to corrosive environments. Hot-worked (HW) corrugated bars of both DSSs are analyzed and their corrosion behaviour is compared with that of the HW and cold-worked (CW) corrugated bars of S30403. The corrosion performance is characterized through cyclic polarization curves in 8 different solutions that simulate those contained inside the pores of concrete in different circumstances. The obtained results justify a great interest in the studied lean DSS grades with respect to their use as reinforcements. Moreover, it is proved that the corrugated surface of a bar is clearly less corrosion resistant than the centre of the bar. The processing method of producing reinforcements influences not only the pitting susceptibility but also the pitting morphology.Publicad

    Effect on wear resistance of nanoparticles addition to a powder polyester coating through ball milling

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    Proceeding of: 13th Coatings Science International Conference (COSI 2017),The wear properties of a textured polyester powder coating with pyrogenic silica nanoparticles addition were evaluated. Raw powders of a commercial, textured polyester organic coating were mixed with low amounts of SiO2 nanoparticles (0.5&-3 wt%) using ball milling, a simple and economical method. Nanoparticles were mixed into the powder of thermoset organic coating for 10 min in a two-body planetary ball mill. Particle size distribution of the powder was measured to evaluate the milling effect. The coatings were applied and cured in an industrial installation on aluminum substrates. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) images of the coatings were taken to analyze the homogeneity of the organic coating. Roughness, gloss and color were measured in order to evaluate their appearance. The effect of nanoparticles on abrasive and erosion wear performances was measured. Pin-on-disk wear tests were carried out. Erosion measurements were performed with free fall of sand on the samples, a test based on ASTM D968 standard. The results showed that the milling process provides a good distribution of nanoparticles as no agglomerates were found. The addition of 0.5 wt% silica nanoparticles allows for improvement of the wear resistance of the coatings.The authors acknowledge the financial support of Interreg SUDOE, through KrEaTive Habitat project (Ref. SOE1/P1/E0307

    Welded, sandblasted, stainless steel corrugated bars in non-carbonated and carbonated mortars: A 9-year corrosion study

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    Three different stainless steel corrugated grades (UNS S20430, S30403 and S32205) were similar welded to stainless steel bars with the same composition and dissimilar welded to carbon steel (CS). After cleaning the welding oxides by sandblasting, the reinforcements were embedded in mortar with chlorides and some of the samples were carbonated. Corrosion activity was monitored using corrosion potential (Ecorr) and electrochemical impedance spectroscopy (EIS). After 8 years of exposure, the samples were anodically polarized. Visual evaluation of the attack was performed after another additional year of exposure. Similar welded stainless steels offer a good durability if they have been sandblasted, except for S20430 when it is embedded in carbonated mortar with chlorides. Dissimilar welded steels are active since the beginning of the exposure for both studied conditions, but sandblasting reduces the corrosion rate of CS compared to non-welded CS bars.The present work was funded by the Spanish Ministry of Science and Innovation through the Project reference BIA2007-66491-C02-02

    Influence of the forming process of corrugated stainless steels on their corrosion behaviour in simulated pore solutions

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    Stainless steels are formed by either hot working (HW) or cold working (CW) when used as reinforcement for concrete structures. The influence of the forming process on the corrosion behaviour is analyzed in depth in the present work. CW and HW corrugated bars of austenitic AISI 304L and 316L, and duplex SAF 2205 grades are studied. The electrochemical behaviour of the corrugated surface and the core of these materials are characterized by Mott Schottky analysis and polarization curves. Tests are carried out in both carbonated and non carbonated Ca(OH)2 solutions. The microstructure and local mechanical properties of these materials are also analysed by means of universal hardness (UH) measurements to complete available information. The results prove that the surface of corrugated bars is far more likely to suffer corrosion than the core of the same material. The corrosion probability and the morphology of the attack induced in corrugated surfaces by anodic polarization clearly differ in HW and CW bars.The authors wish to acknowledge the Spanish Ministry of Science and Innovation (through project BIA2007 66491 C02 02) for its financial support in this research

    Propuesta de BCI basado en RSVP con número reducido de estímulos usando el modo de escritura T9.

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    Se propone un sistema de comunicación para personas con severas deficiencias motoras, como pacientes afectados de esclerosis lateral amiotrófica, usando una interfaz cerebro computadora. El sistema se basa en el paradigma Rapid Serial Visual Presentation que tiene la ventaja de no requerir control oculomotor. Para reducir el tiempo de escritura, hace uso de solo 12 estímulos, es decir, aproximadamente la mitad de los estímulos que usan sistemas para escritura con interfaces cerebro-computadora tradicionales. De forma similar a los sistemas de escritura con teclados predictivos T9, cada estímulo se asoció con varios caracteres por lo que el sistema es soportado por un programa de análisis de palabras para componer la palabra final deseada de entre las posibles alternativas en función de los estímulos seleccionados. El sistema propuesto se ha comparado con un sistema de escritura tradicional de 30 estímulos usando el mismo paradigma de presentación de estímulos. Los resultados obtenidos, aunque con pruebas realizadas sobre un solo usuario sano y, por tanto, muy preliminar, han permitido comprobar la viabilidad del sistema, verificándose que, efectivamente, esa reducción del número de estímulos mejora las prestaciones del sistema de escritura llegándose a doblar su velocidad. Como contrapartida, el sistema propuesto requiere un entrenamiento para su uso al tener que agrupar diferentes caracteres con cada estímulo presentado, pero la propuesta de agrupación realizada permite pensar que el tiempo de aprendizaje será reducido.Ministerio de Ciencia, Innovación y Universidades, el Fondo Europeo de Desarrollo Regional (FEDER) a través del proyecto SICODIS, referencia: PID2021-127261OB-I00 y la Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Corrugated stainless steels embedded in mortar for 9 years: corrosion results of non-carbonated, chloride-contaminated samples

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    Mortar samples reinforced with 5 different corrugated stainless steels were tested for 9 years in 2 different conditions: partial immersion (PI) in 3.5% NaCl, and chloride addition to the mortar and exposure to high relative humidity (HRH). The monitoring during the exposures was carried out with corrosion potential (E-corr) and electrochemical impedance spectroscopy (EIS) measurements. A year before finishing (after 8 years of exposure), the reinforced mortar samples were anodically polarised to obtain more information about the pitting resistance of the passive layers formed under the different conditions. The last year of exposure was established to study the progress or repassivation of the pits. The PI is the most aggressive testing condition and it causes low-intensity corrosion in S20430 austenitic stainless steel after 7 years of exposure. The S32205 duplex stainless steel shows very good corrosion behaviourThe present work was funded by the Spanish Ministry of Science and Innovation through the Project reference BIA2007 66491 C02 02

    How efficient deep-learning object detectors are?

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    Deep-learning object-detection architectures are gaining attraction, as they are used for critical tasks in relevant environments such as health, self-driving, industry, security, and robots. Notwithstanding, the available architectures provide variable performance results depending on the scenario under consideration. Challenges are usually used to evaluate such performance only in terms of accuracy. In this work, instead of proposing a new architecture, we overcome the limitations of those challenges by proposing a computationally undemanding comparative model based on several Data Envelopment Analysis (DEA) strategies, not only for the comparison of deep-learning architectures, but also to detect which parameters are the most relevant features for achieving efficiency. In addition, the proposed model provides with a set of recommendations to improve object-detection frameworks. Those measures may be applied in future high-performance meta-architectures, since this model requires lower computational and temporal requirements compared to the traditional strategy based on training neural networks – based on the trial-error method – for each configurable parameter. To this aim, the presented model evaluates 16 parameters of 139 configurations of well-known detectors present in the Google data set [1]

    ¿Where do we go? OnTheWay: A prediction system for spatial locations

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    Ponencia presentada en: I International Conference on Ubiquitous Computing. Alcalá de Henares, Madrid, Spain, June 7-9, 2006In ubiquitous computing we need to know the present context in order to interact properly with the nearby smart elements. When we are moving outdoors, mobile devices take a very important role because they provide us with a link between the world outside and ourselves through means of intelligent interfaces. There are a lot of situations in which it would be very useful to know or foresee the future context, i.e. as a geographic environment, in which we could find ourselves in a near future, and at the same time being able to use that information from our devices. Therefore we must preview this location with enough precision and time and be able to use this information from our mobile device. In our “OnTheWay” system, we used GPS technology and databases made of past paths taken by a person, in order to predict the next location, once we had begun a new course, comparing the new one with those ones stored. The results were amazing: from the data collected about paths travelled during a month and five days, we got the actual destination in 98% of cases, when we have only made a 30,35% of the total path. Therefore, including statistic and semantic information will allow us to upgrade our results, due to the sedentary human behaviour, the small number of frequently visited locations and the fact that the paths used to arrive to these locations are usually the sam

    Evolution of the multifractal parameters along different steps of a seismic activity: The example of Canterbury 2000–2018 (New Zealand)

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    The multifractal detrended fluctuation algorithm is applied to a series of distances and elapsed times between consecutive earthquakes recorded along the years 2000–2018 in the Canterbury region (New Zealand). The time evolution of several multifractal parameters (Hurst exponent, Hölder central and maximum exponents, spectral amplitude, asymmetry, and complexity index) is analyzed. Peaks of multifractal parameters, with statistical significance exceeding 95%, are associated with three earthquakes of notable magnitude (equaling or exceeding Mw = 5.7). Additionally, some other peaks are also associated with the swarm of earthquakes of moderate magnitude. Possible shortcomings created by this assignment to mainshocks or swarms can be removed by comparing the results corresponding to elapsed times and interevent distances between consecutive events. Additionally, the Buishand test, which is used to verify the statistical significance of the detected peaks, also discriminates between mainshocks of notable seismic magnitude and swarms of earthquakes with moderate magnitude. The obtained results, based on the multifractal structure of the seismic activity, could also represent some advances in predicting, with sufficient time, forthcoming mainshocks of high magnitude and mitigate their destructive effects.The research leading to these results has received funding from the European Union’s Horizon 2020 research and innovation program, under Grant Agreement No. 823844, the ChEESE CoE Project.Peer ReviewedPostprint (published version
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