Análisis del ciclo de vida de un edificio con estructura de madera contralaminada en Granada-España

A residential building with cross-laminated timber structure in Granada (Spain) was analyzed using the life cycle assessment methodology, life cycle energy analysis and sensitivity analysis to changes in efficiency of operating energy, materials database, transport distances and different scenarios for C&DW. The environmental impacts of the materials and construction production and embedded energy were relatively significant. The global warming impact category was very low due to the CO2 sequestration of wooden materials. Sensitivity analysis revealed that the most significant reduction in environmental impact was achieved through improvements in energy efficiency, high uncertainty in the impacts of the environmental product declaration, the low effect of long-distance transport on the overall impact and the feasibility of the objective of recovery of the Waste Framework Directive by 2020 (above 70%).Se ha estudiado un edificio residencial con estructura de madera laminada en Granada (España) con la metodología de análisis del ciclo de vida, análisis energético del ciclo de vida y análisis de sensibilidad a cambios en la eficiencia energética durante el uso, bases de datos, distancia del transporte y diferentes escenarios para los residuos. Los impactos ambientales de las etapas de producción de materiales y construcción, así como la energía embebida fueron relativamente significantes. El valor del calentamiento global ha sido muy bajo debido al secuestro de CO2 por la madera. El análisis de sensibilidad ha revelado que la mayor reducción se consigue con la mejora de la eficiencia energética, la alta incertidumbre en los impactos de las declaraciones ambientales de producto, el escaso efecto del transporte de larga distancia sobre los impactos totales y la viabilidad de conseguir el objetivo de valorización de la Directiva Marco para el horizonte 2020 (mayor del 70%).This research has been funded by the research contract: “Riesgo y sostenibilidad en los proyectos de ingeniería y edificación” (Fundación Universidad de Granada – UCOP Construcciones, SA, contract No. 3418-00). Construction Project & Site Data have been provided by Bonsai Arquitectos (Mr. Llopis) and Invesia Corporación

Self-pulsing dynamics of ultrasound in a magnetoacoustic resonator

A theoretical model of parametric magnetostrictive generator of ultrasound is considered, taking into account magnetic and magnetoacoustic nonlinearities. The stability and temporal dynamics of the system is analized with standard techniques revealing that, for a given set of parameters, the model presents a homoclinic or saddle--loop bifurcation, which predicts that the ultrasound is emitted in the form of pulses or spikes with arbitrarily low frequency.Comment: 5 pages, 5 figure

Electronic cigarette use among adult population: a cross-sectional study in Barcelona, Spain (2013–2014)

Objective: This study seeks to analyse the prevalence and correlates of electronic cigarette (e-cigarette) use, purchase location and satisfaction with its use in a sample of the general population of the city of Barcelona, Spain. Design, setting and participants We used participants from a longitudinal study of a representative sample of the adult (≥16 years old) population of Barcelona (336 men and 400 women). The field work was conducted between May 2013 and February 2014. We computed the prevalence, adjusted odds ratios (ORs) and their corresponding 95% confidence interval (CI). Results: The prevalence of ever e-cigarette use was 6.5% (95% CI 4.7% to 8.3%): 1.6% current use, 2.2% past use and 2.7% only e-cigarette experimentation. 75% (95% CI 62.8% to 87.3%) of ever e-cigarette users were current cigarette smokers at the moment of the interview. E-cigarette use was more likely among current smokers (OR=54.57; 95% CI 7.33 to 406.38) and highly dependent cigarette smokers (OR=3.96; 95% CI 1.60 to 9.82). 62.5% of the ever users charged their e-cigarettes with nicotine with 70% of them obtaining the liquids with nicotine in a specialised shop. 39.6% of ever e-cigarette users were not satisfied with their use, a similar percentage of not satisfied expressing the smokers (38.9%) and there were no statistically significant differences in the satisfaction between the users of e-cigarettes with and without nicotine. Conclusions: E-cigarette use is strongly associated with current smoking (dual use) and most users continue to be addicted to nicotine. Six out of 10 e-cigarette users preferred devices that deliver nicotine. The satisfaction with e-cigarette use is very low

Excitability in a nonlinear magnetoacoustic resonator

We report a nonlinear acoustic system displaying excitability. The considered system is a magnetostrictive material where acoustic waves are parametrically generated. For a set of parameters, the system presents homoclinic and heteroclinic dynamics, whose boundaries define a excitability domain. The excitable behaviour is characterized by analyzing the response of the system to different external stimuli. Single spiking and bursting regimes have been identified.Comment: 4 pages, 5 figure

GPS, LiDAR and VNIR data to monitor the spatial behavior of grazing sheep

Traditional knowledge about the behavior of grazing livestock is about to disappear. Shepherds well know that sheep behavior follows non-random patterns. As a novel alternative to seeking behavioral patterns, this study quantified the grazing activities of two sheep flocks of Churra breed (both in the same area but separated by 10 years) based on Global Position System (GPS) monitoring and remote monitoring sensing techniques. In the first monitoring period (2009-10), geolocations were recorded every 5 min (4, 240 records), while in the second one (2018-20), records were taken every 30 min (7, 636 records). The data were clustered based on the day/night and the activity (resting, moving, or grazing). An airborne LiDAR dataset was used to study the slope, aspect, and vegetation height. Four visible-infrared orthophotographs were mosaicked and classified to obtain the land use/land cover (LU/LC) map. Then, GPS locations were overlain on the terrain features, and a Chi-square test evaluated the relationships between locations and terrain features. Three spatial statistics (directional distribution, Kernel density, and Hot Spot analysis) were also calculated. Results in both monitoring periods suggested that the spatial distribution of free-grazing ewes was non-random. The flocks showed strong preferences for grazing areas with gentle north-facing slopes, where the herbaceous layer formed by pasture predominates. The geostatistical analyses of the sheep locations corroborated those preferences. Geotechnologies have emerged as a potent tool to demonstrate the influence of environmental and terrain attributes on the non-random spatial behavior of grazing sheep. © 2022 Malque Publishing. All rights reserved

Influence of Doping and Nanostructuration on n-Type Bi2(Te0.8Se0.2)3 Alloys Synthesized by Arc Melting

In competitive thermoelectric devices for energy conversion and generation, high-efficiency materials of both n-type and p-type are required. For this, Bi2Te3-based alloys have the best thermoelectric properties in room temperature applications. Partial replacement of tellurium by selenium is expected to introduce new donor states in the band gap, which would alter electrical conductivity and thermopower. We report on the preparation of n-type Bi2(Te1-xSex)3 solid solutions by a straightforward arc-melting technique, yielding nanostructured polycrystalline pellets. X-ray and neutron powder diffraction was used to assess Se inclusion, also indicating that the interactions between quintuple layers constituting this material are weakened upon Se doping, while the covalency of intralayer bonds is augmented. Moreover, scanning electron microscopy shows large surfaces perpendicular to the c crystallographic axis assembled as stacked sheets. Grain boundaries related to this 2D nanostructuration affect the thermal conductivity reducing it below 0.8 Wm−1K−1 at room temperature. Furthermore, Se doping increases the absolute Seebeck coefficient up to −140 μV K−1 at 400 K, which is also beneficial for improved thermoelectric efficiency.This research was funded by the Spanish Ministry of Economy and Competitivity for granting the project MAT2013-41099-R.Peer reviewe