Enhanced CO2 Methanation by New Microstructured Reactor Concept and Design

A novel multichannel minireactor with channel internal diameter in the range of millimeters has been conceptually designed and constructed. Its configuration confers to the new concept reactor some features and advantages compared to conventional fixed-bed reactors g.e. better mass-transfer, avoid hot-spots formation, increased performance (10–20%). Consequently, this new reactor concept is ideal to be applied to exothermic reactions such as the Sabatier reaction that demands continuous removal of the heat produced to avoid hot-spot formation and the sintering of the catalyst. Thanks to its configuration, this reactor could control effectively the heat generated by the reaction and several tests were carried out to validate the reactor features. The results obtained demonstrate that the catalysts activity in the reaction is improved with the application of the novel reactor respect the conventional fixed- and fluidized-bed ones and neither catalyst sintering, nor pressure drop was appreciated during the catalytic tests. At the best reaction conditions, Tecnalia’s multichannel minireactor can handle 820 Nm3/h of CO2 per square meter of channel section showing the enormous potential of the new reactor concept.The authors gratefully acknowledge the Spanish Ministry of Economy and Competitiveness (MINECO) funding under the project RENOVAGAS (RTC-2014-2975-3). Likewise, the authors want to acknowledge the valuable contribution of other colleagues from other entities participating in the project

On the scaling of the damping time for resonantly damped oscillations in coronal loops

There is not as yet full agreement on the mechanism that causes the rapid damping of the oscillations observed by TRACE in coronal loops. It has been suggested that the variation of the observed values of the damping time as function of the corresponding observed values of the period contains information on the possible damping mechanism. The aim of this Letter is to show that, for resonant absorption, this is definitely not the case unless detailed a priori information on the individual loops is available

The key role of off-axis singularities in free-space vortex transmutation

We experimentally demonstrate the generation of off-axis phase singularities in a vortex transmutation process induced by the breaking of rotational symmetry. The process takes place in free space by launching a highly-charged vortex, owning full rotational symmetry, into a linear thin diffractive element presenting discrete rotational symmetry. It is shown that off-axis phase singularities follow straight dark rays bifurcating from the symmetry axis. This phenomenon may provide new routes towards the spatial control of multiple phase singularities for applications in atom trapping and particle manipulation.Comment: 4 pages, 4 figures, to appear in Applied Physics B: Lasers and Optic

Treatment of end-of-life concrete in an innovative heating-air classification system for circular cement-based products

A stronger commitment towards Green Building and circular economy, in response to environmental concerns and economic trends, is evident in modern industrial cement and concrete production processes. The critical demand for an overall reduction in the environmental impact of the construction sector can be met through the consumption of high-grade supplementary raw materials. Advanced solutions are under development in current research activities that will be capable of up-cycling larger quantities of valuable raw materials from the fine fractions of End-of-Life (EoL) concrete waste. New technology, in particular the Heating-Air classification System (HAS), simultaneously applies a combination of heating and separation processes within a fluidized bed-like chamber under controlled temperatures (±600 °C) and treatment times (25–40 s). In that process, moisture and contaminants are removed from the EoL fine concrete aggregates (0–4 mm), yielding improved fine fractions, and ultrafine recycled concrete particles (<0.125 mm), consisting mainly of hydrated cement, thereby adding value to finer EoL concrete fractions. In this study, two types of ultrafine recycled concrete (either siliceous or limestone EoL concrete waste) are treated in a pilot HAS technology for their conversion into Supplementary Cementitious Material (SCM). The physico-chemical effect of the ultrafine recycled concrete particles and their potential use as SCM in new cement-based products is assessed by employing substitutions of up to 10% of the conventional binder. The environmental viability of their use as SCM is then evaluated in a Life Cycle Assessment (LCA). The results demonstrated accelerated hydration kinetics of the mortars that incorporated these SCMs at early ages and higher mechanical strengths at all curing ages. Optimal substitutions were established at 5%. The results suggested that the overall environmental impact could be reduced by up to 5% when employing the ultrafine recycled concrete particles as SCM in circular cement-based products, reducing greenhouse gas emissions by as much as 41 kg CO2 eq./ton of cement (i.e. 80 million tons CO2 eq./year). Finally, the environmental impacts were reduced even further by running the HAS on biofuel rather than fossil fuel.The authors of the present paper, prepared in the framework ofthe Project VEEP "Cost-Effective Recycling of C&DW in High AddedValue Energy Efficient Prefabricated Concrete Components forMassive Retrofitting of our Built Environment", wish to acknowl-edge the European Commission for its support. This project hasreceived funding from the European Union’s Horizon 2020 researchand innovation programme under grant agreement No 723582.This paper reflects only the author’s view and the European Com-mission is not responsible for any use that may be made of theinformation it contains.The authors are also grateful to the Spanish Ministry of Science,Innovation and Universities (MICIU) and the European RegionalDevelopment Fund (FEDER) for funding this line of research(RTI2018-097074-B-C21)

Evolución de las publicaciones en neurología clínica en España, Francia, Italia y Alemania en el período 2000-2009

This study analyzes the productivity and visibility of Spanish publications in the area of clinical neurology in the period 2000-2009 and compared with those for Italy, France and Germany. MATERIALS AND METHODS: We used the database Web of Science. The analysis (annual and in five-year) was restricted to the citable documents (original articles, reviews and proceedings papers). Bibliometric indicators used were the number of publications, citations received by publications and Hirsch's h-index. We also assessed the slope of the annual growth rate (b), the number of publications by language and the international collaboration. RESULTS: In the period 2000-2009 there were 46,114 publications in neurology clinic of which 6,998 were Spanish publications (h = 75), 11,629 in Italy (h = 101), French 9,745 (h = 102) and 20,143 in Germany (h = 124). The rate of increase in the total number of publications in Spain (b = 15) was lower than that observed in Italy (b = 65), Germany (b = 61) or France (b = 34). In the case of publications in English, the growth rate was higher for Spain (b = 37) than for France (b = 36) but lower than for Germany (b = 54) and Italy (b = 65). CONCLUSIONS: Although the total number of publications and the observed increase are lower in Spain compared to Italy, France or Germany, the Spanish publications in Clinical Neurology shows good trend indicators with regard to publications in English and international collaboration. This improvement was associated with greater visibility as showed by the five-year analysis of citations received by Spanish publications

Financing public goods and attitudes toward immigration

We study a model where individuals choose both the level of provision of a public good and the quota of low-skilled immigrants that are allowed into the country. Individuals can supplement the public good in the private market. Immigrants affect natives through three channels: (i) the labor market; (ii) tax collection; (iii) the quality of the public good. We find that the higher the political weight of the rich (highly skilled) is, the less tolerant the poor and the middle-class are toward immigration and the more demanding they are toward increasing public spending. The rich are the most favorable to immigration. As they have more weight, the political outcome is closer to their preferences and further from the preferences of the other groups. We use data from the European Social Survey to test the implications of our model.Gabriel Romero thanks CONICYT FONDECYT INICIACION (grant number 11121155) for financial support. Iñigo Iturbe-Ormaetxe thanks financial support from Ministerio de Economía y Competitividad (ECO2012-34928), Generalitat Valenciana (Prometeo/2013/037) and from Instituto Valenciano de Investigaciones Económicas (IVIE)

Plastically-Induced Volume Deformation of Nanocrystalline α-Fe with a '110' Columnar Structure

Volume changes accompanying the plastic deformation at 300 K of nanocrystalline samples of α-Fe with a columnar grain structure possessing a ⟨11¯0⟩ random fiber texture has been obtained from molecular dynamics (MD) simulations. The samples were strained in tension along the common axial direction of the columnar grains. After removal of the elastic volume change, the evolution of plastic volume strain was obtained. Small but non-negligible volume dilations or contractions are observed depending on size (samples of very small grain size show volume contraction). The rate of volume change is high during the first 10% plastic deformation and continues at a low pace thereafter; the first 10% deformation represents a transient in the stress–strain behavior too. The complex behavior observed is reasonably explained by the superposition of contributions from different plastically-induced structural changes to the mass density change: Mainly from changes of grain size, grain boundary structure, dislocation density and density of point-defects. The results are of interest for the development of crystal plasticity theories not restricted by the volume conserving assumption

Characterizing physiological and symptomatic variation in menstrual cycles using self-tracked mobile health data

The menstrual cycle is a key indicator of overall health for women of reproductive age. Previously, menstruation was primarily studied through survey results; however, as menstrual tracking mobile apps become more widely adopted, they provide an increasingly large, content-rich source of menstrual health experiences and behaviors over time. By exploring a database of user-tracked observations from the Clue app by BioWink of over 378,000 users and 4.9 million natural cycles, we show that self-reported menstrual tracker data can reveal statistically significant relationships between per-person cycle length variability and self-reported qualitative symptoms. A concern for self-tracked data is that they reflect not only physiological behaviors, but also the engagement dynamics of app users. To mitigate such potential artifacts, we develop a procedure to exclude cycles lacking user engagement, thereby allowing us to better distinguish true menstrual patterns from tracking anomalies. We uncover that women located at different ends of the menstrual variability spectrum, based on the consistency of their cycle length statistics, exhibit statistically significant differences in their cycle characteristics and symptom tracking patterns. We also find that cycle and period length statistics are stationary over the app usage timeline across the variability spectrum. The symptoms that we identify as showing statistically significant association with timing data can be useful to clinicians and users for predicting cycle variability from symptoms or as potential health indicators for conditions like endometriosis. Our findings showcase the potential of longitudinal, high-resolution self-tracked data to improve understanding of menstruation and women's health as a whole.Comment: The Supplementary Information for this work, as well as the code required for data pre-processing and producing results is available in https://github.com/iurteaga/menstrual_cycle_analysi