1,189 research outputs found

    New 92S6 mesoporous glass: Influence of surfactant carbon chain length on the structure, pore morphology and bioactivity

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    International audienceThe main objective of the present work was to investigate the effect of surfactant chain length on the structure, porosity and bioactivity of 92S6 (92% SiO2, 6% CaO, and 2% P2O5 mol%) mesoporous sol-gel glasses. The aim was to provide a basis for controlling the porosity of the glass to obtain a control of bioactive behavior. A series of mesoporous bioactive glasses were synthesized using three different surfactants (C10H20BrN, C19H42BrN, C22H48BrN). Surfactant type dependence on the textural properties, particularly porosity and bioactivity were studied. Result indicate that the bioactivity factors were improved by a short surfactant carbon length

    Sharing the Costs and Benefits of Energy and Resource Activity: a new book by SEERIL’s Academic Advisory Group

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    This article summarises research in the field of energy and natural resources law, on the subject of the sharing of costs and benefits between developer companies, governments and local communities. It addresses a new phase in the sharing of costs and benefits that is readily discerned in many countries worldwide, and which compels a shift in thinking that is centred more traditionally on environmental and resource royalty regimes

    Hábitos de estudio y deserción escolar en estudiantes de básica superior de una escuela de Cascol, 2019

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    El presente investigación el objeto fue Identificar el nivel de hábitos de estudio y el nivel de deserción escolar en los estudiantes de básica superior de una escuela de Cascol, 2019. Existen muchos factores que pueden llevar a la decisión de un estudiante de abandonar la escuela, en este caso las habilidades de estudio débiles, contribuyen un problema para presentar dificultades en la escuela; diseño de la investigación fue correlacional, de tipo no experimental con enfoque transversal, la muestra de 100 estudiantes; el tipo muestreo fue no probabilístico, la técnica utilizada fue la encuesta, dirigida independientemente para determinar las causas de la problemática de forma directa. Resultados: el 45% femenino y 55% masculino, la relación que existe entre los hábitos de estudios y condiciones económicas fue el 52% indicó a veces, el 47% señaló siempre y el 1% expresó que nunca, las metodologías de los docentes están en niveles regulares y buenos dado que el 57% seleccionó la alternativa a veces, el 42% siempre y tan solo el 1% seleccionó nunca; acerca de la relación que existe entre hábitos de estudio y la deserción escolar de los estudiantes se obtuvo una significancia de P=0,000 (0,000<0,01) por lo que se procede a rechazar la hipótesis nula y se acepta la alternativa en la que se da a conocer que si existe relación entre las variables de estudios, En conclusión en lo que significó que existe un nivel y significativo de correlación entre ellas

    Excess entropy and thermal behavior of Cu- and Ti-doped bioactive glasses

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    International audienceBioactive glasses belong to the ceramic family. They are good materials for implantation due to their excellent capacities to create an intimate bond with bones. Copper is known for its anti-inflammatory, antibacterial, and antifungal properties. Titanium is biocompatible and resistant to corrosion. These chemical elements can be introduced in bioactive glasses to provide a wide variety of uses and to enhance the physiological properties of implanted biomaterials. In this work, bioactive glasses doped with different contents of copper and titanium were synthesized by the melting method. The purpose is to study the effect of doping metal element on the thermal characteristics (T g, T c, and T f). The results revealed that the increase of the content of copper and titanium in the glass matrix decreases the melting temperature and induces an increase of the thermal stability. The excess entropies of pure and doped glasses were calculated. Obtained results highlighted the decrease of the excess entropy with the increase of metal elements contents

    Strategies and actions for achieving carbon neutrality in Portuguese residential buildings by 2050

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    As a crucial step in addressing the climate emergency and enhancing energy security, the European Union has set ambitious targets to decarbonise its economy by 2050. While the building sector plays a pivotal role in this transition, being accountable for 36% of the EU’s total carbon emissions, it shows a renovation rate below 1% per year, which is clearly insufficient. To address this challenge, this study uses the cost-optimal methodology from private and social perspectives to assess the cost-effectiveness and environmental impact of five renovation packages with passive and active solutions currently available on the Portuguese market. The results demonstrated that from both perspectives, optimal combinations of market solutions were generally cost-effective and could lead to a 90–99% reduction in energy needs and even to zero carbon levels. Nevertheless, beyond cost-effectiveness, consideration of co-benefits, e.g., social and health improvements, is also crucial, requiring government action. To drive these essential changes, effective policy measures are imperative. Recommendations encompass robust regulatory frameworks, financial support mechanisms, knowledge dissemination, and a shift towards broader-scale renovation. For carbon reduction to be economically attractive, fostering innovative business models and leveraging legal instruments to tackle complex scenarios are needed.This work was partly financed by FCT/MCTES through national funds (PIDDAC) under the R & D Unit Institute for Sustainability and Innovation in Structural Engineering (ISISE), under reference UIDB/04029/2020 and under the Associate Laboratory Advanced Production and Intelligent Systems ARISE under reference LA/P/0112/2020. The work was also partly financed by the program Portugal Norte 2020-Projetos Estruturados I & D, with the reference NORTE 01-0145-FEDER000058—ZeroSkin+ project

    Comparative Study of Nanobioactive Glass Quaternary System 46S6

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    International audienceDifferent bioactive glass systems have been prepared by sol-gel. However, the production of Na2O-containing bioactive glasses by sol-gel methods has proved to be difficult as the sodium nitrate used in the preparation could be lost from the glass structure during filtration and washing. The aim of this study was to prepare the quaternary system 46S6 of bioactive glass by modified sol-gel techniques with a decrease in the time of gelation. In addition, compare the behaviour of the prepared sol-gel bioactive glass system by its corresponding prepared by melting. The obtained glasses were characterized by using several physicochemical techniques; XRD, FTIR, TEM and SEM beside the effect of the glass particles on the viability of osteoblast like cells (Saos-2). Results show that nanopowders 40-60 nm of 46S6 glass system had been prepared by modified sol-gel (acid-base reaction) method at 600°C in just three days at 600°C. Cell viability by MTT assay confirmed the effectiveness of the prepared nanobioactive glass

    disaggregation: An R Package for Bayesian Spatial Disaggregation Modeling

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    Disaggregation modeling, or downscaling, has become an important discipline in epidemiology. Surveillance data, aggregated over large regions, is becoming more common, leading to an increasing demand for modeling frameworks that can deal with this data to understand spatial patterns. Disaggregation regression models use response data aggregated over large heterogeneous regions to make predictions at fine-scale over the region by using fine-scale covariates to inform the heterogeneity. This paper presents the R package disaggregation, which provides functionality to streamline the process of running a disaggregation model for fine-scale predictions

    The Composition of Comets

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    This paper is the result of the International Cometary Workshop, held in Toulouse, France in April 2014, where the participants came together to assess our knowledge of comets prior to the ESA Rosetta Mission. In this paper, we look at the composition of the gas and dust from the comae of comets. With the gas, we cover the various taxonomic studies that have broken comets into groups and compare what is seen at all wavelengths. We also discuss what has been learned from mass spectrometers during flybys. A few caveats for our interpretation are discussed. With dust, much of our information comes from flybys. They include {\it in situ} analyses as well as samples returned to Earth for laboratory measurements. Remote sensing IR observations and polarimetry are also discussed. For both gas and dust, we discuss what instruments the Rosetta spacecraft and Philae lander will bring to bear to improve our understanding of comet 67P/Churyumov-Gerasimenko as "ground-truth" for our previous comprehensive studies. Finally, we summarize some of the initial Rosetta Mission findings.Comment: To appear in Space Science Review
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