3,927 research outputs found

    Elastocaloric Effect in Graphene Kirigami

    Full text link
    Kirigami, a traditional Japanese art of paper-cutting, has recently been explored for its elastocaloric effect (ECE) in kirigami-based materials (KMs), where applying strain induces temperature changes. In this study, we investigate the ECE in a nanoscale graphene kirigami (GK) monolayer, representing the thinnest possible KM, to better understand this phenomenon. Through molecular dynamics simulations, we analyze the temperature change and coefficient of performance (COP) of the nanoscale GK architecture. Our findings reveal that while GKs lack the intricate temperature changes observed in macroscopic KMs, they exhibit a substantial temperature change of approximately 9.32 K (23 times higher than that of macroscopic KMs, which is about 0.4K) for heating and -3.50 K for cooling. Additionally, they demonstrate reasonable COP values of approximately 1.57 and 0.62, respectively. It is noteworthy that the one-atom-thick graphene configuration prevents the occurrence of the complex temperature distribution observed in macroscopic KMs.Comment: 14 pages, 06 figures, and 01 tabl

    Revisiting the outstanding flooding episode of November 1967 in the greater metropolitan Lisbon area

    Get PDF
    The deadliest storm affecting Portugal since, at least, the early 19th century, took place on the 25 and 26 November 1967 causing more than 500 fatalities. Here we provide a comprehensive multi-disciplinary assessment of this episode, including the main socio-economic impacts, particularly the numbers and location of victims (dead, injured, homeless and evacuated). Based on the sub-daily time series of a representative station, and its Intensity-Duration-Frequency curves, we have found that the exceptionality of this rainfall event is particularly linked to rainfall intensities ranging in duration from 4 to 9 hours compatible with return periods of 100-years or more. This range of time scale is similar to the estimated concentration time values of the hydrographic basins affected by the flash flood event. Most victims were sleeping or were caught by surprise at home in the small river catchments within the greater metropolitan Lisbon area. The majority of people who died or who were severely affected by the flood lived in degraded housing conditions often raised in a clandestine way, occupying flood plains near the stream beds. This level of destruction observed at the time is in stark contrast to what was observed in subsequent episodes of similar amplitude. In particular, since 1967 the Lisbon area, was struck by two comparable intense precipitation events in 1983 and 2008 but generating considerably fewer deaths and evacuated people.info:eu-repo/semantics/publishedVersio

    Analysis of energy security and sustainability in future low carbon scenarios for Brazil

    Get PDF
    This study estimated a series of indicators to assess the energy security of supply and global and local environmental impacts under different mitigation scenarios through 2050 in Brazil, designed with the integrated optimisation energy system model MESSAGE-BRAZIL. The assessment of interactions between environmental impacts and energy security dimensions was complemented through the application of life cycle assessment (LCA) methodology. Overall results imply energy security establishes more synergies than trade-offs in increasingly stringent mitigation scenarios, especially patent within the sustainability dimension, which increases energy security and provides additional benefits regarding climate change mitigation and air pollution emissions. It is still necessary to extend analysis to other energy sectors in addition to the power supply sector, to promote a better understanding of repercussions of energy scenario expansion in energy security.This work was funded by the Brazilian research funding agencies CNPq and CAPES, under the Science Without Borders Programme, and the Marie Curie International Research Staff Exchange Scheme Fellowship within the 7th European Union Framework Programme, under the project NETEP- European Brazilian Network on Energy Planning (PIRSES-GA-2013-612263). We also acknowledge funding from US EPA and US AID (under Interagency Agreements DW89923040 and DW89923951US), through the LAMP, and the European Union, through the CLIMACAP project (EuropeAid/131944/C/SER/Multi)

    Geodiversity assessment of the Xingu drainage basin

    Get PDF
    Artigo com mapa em anexoGeodiversity is a recent concept that refers to the abiotic variety of nature. It is defined as the range of geological (rocks, minerals, fossils), geomorphological (landforms, processes) and soil features, including their assemblages, relationships, properties, interpretation and systems. In this work, a method of quantitative assessment of geodiversity was applied to the Xingu drainage basin (Amazoˆnia – Brazil). The method is based on the quantification and integration of abiotic features represented on thematic maps at scales ranging from 1:250,000 to 1:2,500,000, overlaid by a 1:25,000 systematic grid. In order to calculate the final geodiversity index, five partial numerical indices representing the main components of geodiversity were drawn compiled: geology, geomorphology, soil, palaeontology and mineral occurrences. The resulting Geodiversity Index map is presented in the form of five isoline classes. The objective of this method is to present such a mapping technique as a tool for environmental planning, particularly for the identification and definition of priority areas for conservation.Fundação para a Ciência e a Tecnologia (FCT)CAPE

    Assisted Reproductive Techniques on South American Wild Mammals

    Get PDF
    For South American wild mammals, assisted reproductive techniques (ARTs) have been established in accordance with the procedures used for domestic mammals. However, often, it is not possible to infer the experimental conditions from one species to another. In general, the use of these ARTs aims the conservation of the animal genetic material, using gamete manipulation, embryo technology by in vivo or in vitro methods, and cloning. In all animals, the previous knowledge of reproductive physiology becomes the starting point for the use of ARTs in the expansion of all species of interest. In this sense, the purpose of this chapter is to develop an approach of theoretical, technical, and applied aspects of the ARTs in South American wild mammals, with emphasis on the state-of-the-art and its progress and perspectives

    Optimal design of THEDES based on Perillyl Alcohol and Ibuprofen

    Get PDF
    Therapeutic deep eutectic systems (THEDES) have dramatically expanded their popularity in the pharmaceutical field due to their ability to increase active pharmaceutical ingredients (APIs) bioavailability. However, their biological performance has not yet been carefully scrutinized. Herein, THEDES based on the binary mixture of perillyl alcohol (POH) and ibuprofen (IBU) were prepared using different molar ratios. Our comprehensive strategy includes the characterization of their thermal and structural behavior to identify the molar ratios that successfully form deep eutectic systems. The in vitro solubility of the different systems prepared has demonstrated that, unlike other reported examples, the presence of the terpene did not affect the solubility of the anti-inflammatory agent in a physiological simulated media. The biological performance of the systems was studied in terms of their antimicrobial activity against a wide panel of microorganisms. The examined THEDES showed relevant antimicrobial activity against all tested microbial strains, with the exception of P. aeruginosa. A synergistic effect from the combination of POH and IBU as a eutectic system was verified. Furthermore, the cytotoxic profile of these eutectic systems towards colorectal cancer (CRC) in vitro cell models was also evaluated. The results provide the indication that the cell viability varies in a dose-dependent manner, with a selective THEDES action towards CRC cells. With tunable bioactivities in a ratio-dependent manner, THEDES enhanced the antimicrobial and anticancer properties, representing a possible alternative to conventional therapies. Therefore, this study provides foreseeable indications about the utility of THEDES based on POH and IBU as strong candidates for novel active pharmaceutical systems.Foundation for Science and Technology (FCT), through project PTDC/BBB-490 EBB/1676/2014–Des.Zyme, Light2Skin-PTDC/CTM-CTM/29813/2017 and ERC-2016-CoG 725034 (ERC Consolidator Grant Des.solve). E.S. would also like to acknowledge the financial support by the FCT through the doctoral grant with reference number SFHR/BD/143902/2019. J.M.S. would also like to acknowledge the financial support by the FCT through the post-doctoral grant with reference number SFRH/BPD/116779/201

    Sun-Graphyne: A New 2D Carbon Allotrope with Dirac Cones

    Full text link
    Due to the success achieved by graphene, several 2D carbon-based allotropes were theoretically predicted and experimentally synthesized. Here, we propose a new 2D carbon allotrope named Sun-Graphyne (S-GY). We used density functional theory and reactive molecular dynamics simulations to investigate its mechanical, structural, electronic, and optical properties. The results showed that S-GY exhibits good dynamical and thermal stabilities. Its formation energy and elastic moduli are -8.57 eV/atom and 262.37 GPa, respectively. S-GY is a semi-metal and presents two Dirac cones in its band structure. This material is transparent, and its intense optical activity is limited to the infrared region. Remarkably, the band structure of S-GY remains practically unchanged at even moderate strain regimes. As far as we know, this is the first 2D carbon allotrope to exhibit this behaviour.Comment: 17 pages, and 11 figure

    The efficacy of a gambling prevention program among high-school students

    Get PDF
    Youth problem gambling has become an emergent public health issue, and adolescents constitute a vulnerable age group for the development of gambling-related problems. Although there is research concerning the risk factors of youth problem gambling, rigorous evaluations of the effectiveness of preventive initiatives is still rare. The present study evaluated the efficacy of an integrative intervention to prevent youth problem gambling based on a multidimensional set of factors including gambling-related knowledge, misconceptions, attitudes, gambling frequency, amount of money spent, total hours spent gambling per week, and sensation seeking. A pre- and post-test design was performed with 111 Portuguese high-school students randomly assigned to two groups (experimental and control). The findings demonstrated that the intervention was effective in improving correct knowledge about gambling, reducing misconceptions and attitudes, and in decreasing the total hours spent gambling per week. The intervention was also effective in reducing the number of at-risk/problem gamblers during the study period. Furthermore, these findings were stable after a 6-week follow-up. Overall, the intervention program appeared to be effective in correcting some gambling-related behaviours, and provides suggestions for future interventions
    • …
    corecore