47 research outputs found

    Unraveling the nature of active sites onto copper/ceria-zirconia catalysts for low temperature CO oxidation

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    The aim of this research is an attempt to shed some light on the understanding of the nature of the active sites and the generated synergies in the copper/ceria-zirconia formulations for low temperature CO oxidation by means of the creation of copper entities with different physico-chemical nature. For this reason, several CuOx/ceria-zirconia catalysts, with different Cu contents and different methods to incorporate copper species, were synthesized. Focus was specially put in this case trying to link the results of CO oxidation catalytic tests with the CO-temperature programmed reduction profiles/approximate estimations and selected characterization parameters in order to find out correlations among catalysts' properties/reducibility and catalytic behaviors, especially those corresponding to the nature and roles of the different CuOx species in contact with ceria-based support on catalytic activity. Results reveal a significant improvement in CO conversion compared to the ceria-zirconia support by adding a small amount of copper loading (as low as 0.5 %), emphasizing the paramount role of copper incorporated by the method of IWI. From 0.5 up to 2% of copper loading, an interesting increase gradual trend in activity and reducibility can be noted. It should be mentioned that all the catalysts obtained by this procedure are more catalytically active towards CO oxidation than 1%Pt/Al2O3 at low temperatures (T < 130 degrees C). CO-TPR results show that the reducibility of these catalysts is in line with their CO oxidation activity. The method of preparation has been revealed as a critical variable in the catalytic performance, and quite similar catalytic activities can be reached from different synthesis methods and different copper contents, due to the similar nature and type of CuOx species generated over the catalysts' surface, identified by the CO-TPR profiles and the rest of characterization data. Finally, IWI method seems to be the best one among those tested, thus combining superior areas of both alpha and beta contributions assigned on CO-TPR profiles, which seem to be critical in the interpretation of the catalytic behaviors

    BiosecurID: a multimodal biometric database

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    This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: http://dx.doi.org/10.1007/s10044-009-0151-4A new multimodal biometric database, acquired in the framework of the BiosecurID project, is presented together with the description of the acquisition setup and protocol. The database includes 8 unimodal biomet- ric traits, namely: speech, iris, face (still images and videos of talking faces), handwritten signature and handwritten text (on-line dynamic signals and off- line scanned images), fingerprints (acquired with two different sensors), hand (palmprint and contour-geometry) and keystroking. The database comprises 400 subjects and presents features such as: realistic acquisition scenario, bal- anced gender and population distributions, availability of information about particular demographic groups (age, gender, handedness), acquisition of replay attacks for speech and keystroking, skilled forgeries for signatures, and com- patibility with other existing databases. All these characteristics make it very useful in research and development of unimodal and multimodal biometric systems.This work has been supported by the Spanish MEC under project TIC2003-08382-C05-01. The authors J. G. and R. R. are supported by FPU Fellowships from Spanish MEC, the authors M. R. F. and F. A.-F. are supported by FPI Fellowships from CAM, and J. F. is supported by a Marie Curie Fellowship from the European Commission

    Desarrollo tecnológico en ingeniería automotriz

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    El proceso de investigación y desarrollo tecnológico está directamente relacionado con una adecuada metodología de procesos industriales, que cada vez son más exigentes en competitividad, eficiencia energética y de normativas ambientales. Este libro contempla resultados de un proceso de investigación y desarrollo de nuevas técnicas aplicadas en el campo de la Ingeniería Automotriz desde cuatro aristas: eficiencia energética y contaminación ambiental, planificación del transporte, ingeniería del mantenimiento aplicada al transporte y desagregación tecnológica. Este libro conmemora 20 años de formación universitaria salesiana en el sector de transporte y recoge las experiencias y resultados obtenidos asociados con el desarrollo tecnológico en ingeniería automotriz. Para lograr este objetivo, se ha convocado a la comunidad científica, académica y profesionales de la industria automotriz a participar en la publicación. Cada capítulo fue sometido a revisión, evaluación y aprobación por un comité científico altamente calificado, proveniente de seis países: Colombia, Ecuador, España, Guinea Ecuatorial, México y Venezuela. Este trabajo ha sido posible gracias al gran apoyo de la Universidad Politécnica Salesiana (UPS sede Cuenca), Ecuador y Universidad de Los Andes (ULA)

    J.A.: Hill-climbing and brute force attacks on biometric systems: a case study in match-on-card fingerprint verification

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    In this paper, we study the robustness of state-of-theart automatic fingerprint verification systems against hillclimbing and brute-force attacks. We compare the performance of this type of attacks against two different minutiaebased systems, the NIST Fingerprint Image Software 2 (NFIS2) reference system and a Match-on-Card based system. In order to study their success rate, the attacks are analyzed and modified in each scenario. We focus on the influence of initial conditions in hill-climbing attacks, like the number of minutiae in the synthetically generated templates or the performance of each type of modification in the template. We demonstrate how slight modifications in the hill-climbing algorithm lead to very different success rates. 1

    The circularity gap of nations: A multiregional analysis of waste generation, recovery, and stock depletion in 2011

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    Due to increased policy attention on circular economy strategies, many studies have quantified material use and recovery at national and global scales. However, there has been no quantitative analysis of the unrecovered waste that can be potentially reintegrated into the economy as materials or products. This can be interpreted as the gap of material circularity. In this paper we define the circularity gap of a country as the generated waste, plus old materials removed from stocks and durable products disposed (i.e. stock depletion), minus recovered waste. We estimated the circularity gap of 43 nations and 5 rest of the world regions in 2011, using the global, multiregional hybrid-units input-output database EXIOBASE v3.3. Our results show the trends of circularity gap in accordance to each region. For example, the circularity gaps of Europe and North America were between 1.6–2.2 tonnes per capita (t/cap), which are more than twice the global average gap (0.8 t/cap). Although these regions presented the major amount of material recovery, their circularity gaps were mostly related to the levels of stock depletion. In Africa and Asia-Pacific regions, the circularity gap was characterized by a low degree of recovery and stock depletion, with high levels of generated waste. Moreover, we discuss which intervention types can be implemented to minimize the circularity gap of nations.Industrial Ecolog

    Corrigendum to “The circularity gap of nations: a multiregional analysis of waste generation, recovery, and stock depletion in 2011” [Resour. Conserv. Recy. 151 (2019) 104452]

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    Refers toGlenn A. Aguilar-Hernandez, Carlos Pablo Sigüenza-Sanchez, Franco Donati, Stefano Merciai, Jannick Schmidt, João F.D. Rodrigues, Arnold TukkerThe circularity gap of nations: A multiregional analysis of waste generation, recovery, and stock depletion in 2011Resources, Conservation and Recycling, Volume 151, December 2019, Pages 104452https://doi.org/10.1016/j.resconrec.2019.104452Industrial Ecolog

    Evaluation of the SAMe-TT2R2 score to predict the quality of anticoagulation control in patients with venous thromboembolism treated with vitamin K antagonists: Findings from the RIETE registry

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    Background: The time in therapeutic range (TTR) of patients with venous thromboembolism (VTE) treated with vitamin K antagonists (VKA) is usually below recommended, leading to higher frequency of vascular events, bleeding and mortality. The SAMe-TT2R2 prediction score discriminates those patients with high or low probability of obtaining poor INR control and its use is recommended in patients with atrial fibrillation. Its usefulness has been evaluated in patients with VTE, with conflicting results. Method: We included consecutive patients enrolled in Registro Informatizado Enfermedad TromboEmbolica (RIETE), a prospective multicenter VTE registry, treated with VKA for >90 days and a minimum of 3 INR determinations. We analyzed the relationship between the SAMe-TT2R2 score and TTR, determined by the Rosendaal method and by the percentage of INR determinations (after excluding the first month). A ROC curve was calculated considering a cut-off point of TTR ≥65% for good anticoagulation control. Results: 3893 patients were included and classified in high (1411 patients) or low (2482 patients) probability of obtaining poor INR control according to the total score obtained (0–1 points versus 2 points, respectively). TTR, calculated by direct method and Rosendaal method, was 51.2 (±23.4) and 55.4 (±25.9) in the high probability group; and 54.4 (±23.0) and 58.2 (±25.6) in the low probability group, respectively (p < 0.001 for both comparisons). The outcomes were similar between groups. The predictive capacity of the SAMe-TT2R2 score showed an area under the ROC curve of 0.54 (CI 95% 0.52–0.56) and 0.53 (CI 95% 0.51–0.55). Conclusions: In patients with VTE treated with VKA, the SAMe-TT2R2 score discriminated those patients with high probability of obtaining poor INR control, but with a low predictive capacity. Further studies are required to assess the usefulness of the score in clinical decision-making
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