2,511 research outputs found

    Gest√£o de projectos no √Ęmbito da constru√ß√£o sustent√°vel

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    A ind√ļstria da constru√ß√£o, nomeadamente no sector da edifica√ß√£o, baseia-se essencialmente em m√©todos de constru√ß√£o tradicional. Esta ind√ļstria √© caracterizada pelo consumo excessivo de mat√©rias-primas, de recursos energ√©ticos n√£o renov√°veis e pela elevada produ√ß√£o de res√≠duos. Esta realidade √© de todo incompat√≠vel com os des√≠gnios do desenvolvimento sustent√°vel, nos quais se procura a conveni√™ncia harmoniosa entre as dimens√Ķes ambiental, social e econ√≥mica. O desafio da sustentabilidade, colocado √† actividade da constru√ß√£o, tem motivado abordagens distintas, n√£o s√≥ por parte das v√°rias especialidades da engenharia, como tamb√©m da arquitectura. √Č nesta perspectiva, que o presente modelo pretende ser um contributo para uma abordagem inovadora, introduzindo linhas de interven√ß√£o e de orienta√ß√£o, para apoiar e estimular o desenvolvimento de solu√ß√Ķes sustent√°veis em edif√≠cios habitacionais, em qualquer fase do ciclo de evolu√ß√£o de um projecto e das v√°rias especialidades do mesmo. Assim, no sentido de optimizar os recursos envolvidos no projecto s√£o expostas estrat√©gias de interven√ß√£o, com os seguintes objectivos: optimiza√ß√£o do potencial do local, preserva√ß√£o da identidade regional e cultural, minimiza√ß√£o do consumo de energia, utiliza√ß√£o de materiais e produtos de baixo impacto ambiental, redu√ß√£o do consumo de √°gua, redu√ß√£o da produ√ß√£o de emiss√Ķes, res√≠duos e outros poluentes, adequada qualidade do ambiente interior e optimiza√ß√£o das fases de opera√ß√£o e manuten√ß√£o. A ferramenta apresentada surge como um instrumento facilitador para a equipa de projectistas, e que se esta adaptada para o desenvolvimento de projectos de edif√≠cios de habita√ß√£o, dada a g√©nese dos m√©todos utilizados. As solu√ß√Ķes de sustentabilidade apresentadas neste manual emanam dos sistemas de certifica√ß√£o L√≠derA, LEED, BREEAM e SBToolpt. O modelo encontra-se estruturado, no que √†s fases de projecto diz respeito, de acordo com os requisitos expressos na Portaria 701-H/2008 de 29 de Julho, tendo sido igualmente seguido o descrito para os respectivos intervenientes.The construction industry, particularly the building sector, is based mainly on traditional construction methods. This industry is characterized by excessive consumption of raw materials, non-renewable energy resources and high production of waste. This reality is entirely incompatible with the aims of sustainable development, which require a ‚Äúharmonious convergence‚ÄĚ between the environmental, social and economic dimensions. It is therefore necessary to change attitudes and proceedings in a responsible and intelligent way. The sustainability challenge faced by the construction activity has motivated different approaches, not only by the various engineering specialties, but also by the architecture. It is with this background that this document is intended as a contribution to an innovative approach by introducing lines of action and guidance to support and encourage the development of sustainable solutions in residential buildings at any stage of a project and its different specialties. Therefore, in order to optimize the resources involved in the project, are exposed intervention strategies, with the following main objectives: optimizing the potential of the site, preservation of cultural and regional identity, minimize energy consumption, use of materials and products with low environmental impact, reducing the water consumption, reducing the production of emissions, waste and other pollutants, adequate indoor environmental quality and optimization of the operation and maintenance phases. This tool emerges as a facilitator for the design team and is adapted to the development of residential building projects, given the genesis of the methods used. The sustainability solutions presented in this document are based on the certification systems L√≠derA, LEED, BREEAM and SBToolpt. The manual is structured, in the phases of the project concerns, according to the requirements stated in ‚ÄúPortaria 701-H/2008 de 29 de Julho‚ÄĚ

    Desenvolvimento de materiais de cátodo à base de polímeros condutores para baterias de ião sódio

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    Tese de mestrado integrado, Engenharia da Energia e do Ambiente, Universidade de Lisboa, Faculdade de Ci√™ncias, 2018As baterias de i√£o s√≥dio surgem como uma alternativa √†s baterias de i√£o l√≠tio convencionais, mais baratas e mais abundante em termos de recurso. No entanto, o atraso na comercializa√ß√£o das mesmas est√° relacionado com o desenvolvimento de materiais cat√≥dicos com capacidade e potencial semelhante aos existentes nas baterias de i√£o l√≠tio. Assim, este trabalho dedica-se ao desenvolvimento de novos materiais de c√°todo √† base de pol√≠meros eletronicamente condutores capazes de incorporar i√£o s√≥dio durante a descarga e sua expuls√£o durante a carga. Os fluxos m√°ssicos que ocorrem nos filmes polim√©ricos de polietilenodioxiotiofeno dopados com poliestirenosulfonato s√£o investigados por t√©cnicas eletroqu√≠micas, microgravim√©tricas e por efeito miragem. A sua morfologia e constantes diel√©tricas s√£o analisadas, respetivamente, por microscopia de for√ßa at√≥mica e por elipsometria ex-situ. Estes filmes foram sintetizados potenciodinamicamente em meio aquoso com diferente n√ļmero de ciclos e a duas velocidades de varrimento, e potenciostaticamente durante dois per√≠odos de tempo. A caracteriza√ß√£o dos filmes foi realizada em meio org√Ęnico numa ampla janela de potencial. A informa√ß√£o combinada das t√©cnicas microgravim√©tricas e do efeito miragem permitiu a distin√ß√£o entre fluxos de solvente e i√≥nicos, sendo estes √ļltimos avaliados quantitativamente atrav√©s da ferramenta matem√°tica de convolu√ß√£o temporal. Foi identificada a participa√ß√£o dominante do i√£o s√≥dio (95%) nos fluxos i√≥nicos. Os pol√≠meros resistiram a 1000 ciclos de carga/descarga r√°pida, registando perda de massa inferior a 60%. Estes dados suportam a exist√™ncia de dopagem pseudo cati√≥nica quasi-ideal, uma vez que a participa√ß√£o do cati√£o s√≥dio √© completamente dominante durante o processo de convers√£o redox para filmes finos de PEDOT:PSS. Este facto, conjuntamente com um valor de capacidade espec√≠fica superior a 60 mAh.g-1, torna este material bastante competitivo comparativamente aos c√°todos convencionais como √© o caso da perovskite.Sodium ion batteries appear as an alternative less expensive and more abudant than the conventional lithium ion batteries. However, the delay in their commercialization is related to the development of cathode materials with capacity and potential similar to those found in lithium ion batteries. Thus, this work is devoted to the development of new cathode materials based on electronically conductive polymers capable of incorporating sodium ion during discharge and their expulsion during charge. The mass fluxes occurring in the polyethylenedioxothiophene polymer films doped with polystyrenesulfonate are investigated by electrochemical, microgravimetric and by mirage effect techniques. Their morphology and dielectric constants are analyzed, respectively, by atomic force microscopy and ex-situ ellipsometry. These films were synthesized potentiodynamically in aqueous medium with different number of cycles and at two scanning rates, and potentiostatically for two time periods. The characterization of the films was carried out in organic medium in a wide window of potential. The combined information of microgravimetric techniques and the mirage effect allowed the distinction between solvent and ionic fluxes, the latter being evaluated quantitatively through the mathematical tool of temporal convolution. The dominant participation of sodium ion (95%) in the ionic fluxes was identified. The polymers resisted at 1000 load / discharge cycles, with a mass loss of less than 60%. These data support the existence of quasi-ideal pseudo-cation doping, since the participation of the sodium cation is completely dominant during the redox conversion process for PEDOT: PSS thin films. This, together with a specific energy value greater than 60mAh.g-1, makes this material very competitive compared to conventional cathodes such as perovskite

    Can the curriculum be used to estimate critical velocity in young competitive swimmers?

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    The aims of the present study were to assess critical velocity using the swimmer curriculum in front crawl events and to compare critical velocity to the velocity corresponding to a 4 mmol·l(-1) of blood lactate concentration and to the velocity of a 30 min test. The sample included 24 high level male swimmers ranged between 14 and 16 years old. For each subject the critical velocity, the velocity corresponding to a 4 mmol·l(-1) of blood lactate concentration and the mean velocity of a 30 min test were determined. The critical velocity was also estimated by considering the best performance of a swimmer over several distances based on the swimmer curriculum. Critical velocity including 100, 200 and 400 m events was not different from the velocity of 4 mmol·l(-1) of blood lactate concentration. Critical velocity including all the swimmer events was not different from the velocity of a 30 min test. The assessment of critical velocity based upon the swimmer curriculum would therefore seem to be a good approach to determine the aerobic ability of a swimmer. The selection of the events to be included in critical velocity assessment must be a main concern in the evaluation of the swimmer. Key pointsCritical velocity using 100, 200 and 400 m events was not different from the velocity of 4 mmol·l(-1) of blood lactate concentration.Critical velocity using all the swimmer events was not different from the velocity of a 30 min test.The assessment of critical velocity based upon the swimmer curriculum seemed to be a good approach to determine the aerobic capacity of a swimmer.The decision on the events to be analysed must be a main concern in the evaluation of the swimmer critical velocity.info:eu-repo/semantics/publishedVersio

    Influence of 3D microstructure pattern and infill density on the mechanical and thermal properties of PET-G filaments

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    This study aims to evaluate the thermal and mechanical performances of PET-G thermoplastics with different 3D microstructure patterns and infill densities. The production costs were also estimated to identify the most cost-effective solution. A total of 12 infill patterns were analysed, including Gyroid, Grid, Hilbert curve, Line, Rectilinear, Stars, Triangles, 3D Honeycomb, Honeycomb, Concentric, Cubic, and Octagram spiral with a fixed infill density of 25%. Different infill densities ranging from 5% to 20% were also tested to determine the best geometries. Thermal tests were conducted in a hotbox test chamber and mechanical properties were evaluated using a series of three-point bending tests. The study used printing parameters to meet the construction sector‚Äôs specific needs, including a larger nozzle diameter and printing speed. The internal microstructures led to variations of up to 70% in thermal performance and up to 300% in mechanical performance. For each geometry, the mechanical and thermal performance was highly correlated with the infill pattern, where higher infill improved thermal and mechanical performances. The economic performance showed that, in most cases, except for the Honeycomb and 3D Honeycomb, there were no significant cost differences between infill geometries. These findings can provide valuable insights for selecting the optimal 3D printing parameters in the construction industry.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-FEDER-000058‚ÄĒZeroSkin+ project

    Does combined dry land strength and aerobic training inhibit performance of young competitive swimmers?

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    The aim of the current study was twofold: (i) to examine the effects of eight weeks of combined dry land strength and aerobic swimming training for increasing upper and lower body strength, power and swimming performance in young competitive swimmers and, (ii) to assess the effects of a detraining period (strength training cessation) on strength and swimming performance. The participants were divided into two groups: an experimental group (eight boys and four girls) and a control group (six boys and five girls). Apart from normal practice sessions (six training units per week of 1 h and 30 min per day), the experimental group underwent eight weeks (two sessions per week) of strength training. The principal strength exercises were the bench press, the leg extension, and two power exercises such as countermovement jump and medicine ball throwing. Immediately following this strength training program, all the swimmers undertook a 6 week detraining period, maintaining the normal swimming program, without any strength training. Swimming (25 m and 50 m performances, and hydrodynamic drag values), and strength (bench press and leg extension) and power (throwing medicine ball and countermovement jump) performances were tested in three moments: (i) before the experimental period, (ii) after eight weeks of combined strength and swimming training, and (iii) after the six weeks of detraining period. Both experimental and control groups were evaluated. A combined strength and aerobic swimming training allow dry land strength developments in young swimmers. The main data can not clearly state that strength training allowed an enhancement in swimming performance, although a tendency to improve sprint performance due to strength training was noticed. The detraining period showed that, although strength parameters remained stable, swimming performance still improved.info:eu-repo/semantics/publishedVersio

    Can 8-weeks of Training Affect Active Drag in Young Swimmers?

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    The aim of this study was to assess the effects of 8-weeks of training on active drag in young swimmers of both genders. Eight girls and twelve boys' belonging to the same swimming team and with regular competitive participation in national and regional events for the previous two seasons participated in this study. Active drag measurements were conducted in two different evaluation moments: at the beginning of the season and after 8 weeks of training (6.0 ¬Ī 0.15 training units per week, 21.00 ¬Ī 3.23 km per week and 3.50 ¬Ī 0.23 km per training unit). The maximal swimming velocity at the distance of 13 m, active drag and drag coefficient were measured on both trials by the method of small perturbations with the help of an additional hydrodynamic body. After 8 weeks of training, mean active drag (drag force and drag coefficient) decreased in girls and boys, although no significant differences were found between the two trials. It seems that 8 weeks of swimming training were not sufficient to allow significant improvements on swimming technique. Key pointsThe velocity perturbation method seems to be a good, simple and reliable approach to assess active drag in young swimmers.Eight weeks of swimming training were not sufficient to allow significant improvements on swimming hydrodynamics.There were no differences between boys and girls concerning active drag. A possible explanation may be related to the similar values of body mass and height in boys and girls found in this study.Specific training sets concerning technique correction and improvement in young swimmers might be a main aim during training planning.info:eu-repo/semantics/publishedVersio

    Towards a New Science of a Clinical Data Intelligence

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    In this paper we define Clinical Data Intelligence as the analysis of data generated in the clinical routine with the goal of improving patient care. We define a science of a Clinical Data Intelligence as a data analysis that permits the derivation of scientific, i.e., generalizable and reliable results. We argue that a science of a Clinical Data Intelligence is sensible in the context of a Big Data analysis, i.e., with data from many patients and with complete patient information. We discuss that Clinical Data Intelligence requires the joint efforts of knowledge engineering, information extraction (from textual and other unstructured data), and statistics and statistical machine learning. We describe some of our main results as conjectures and relate them to a recently funded research project involving two major German university hospitals.Comment: NIPS 2013 Workshop: Machine Learning for Clinical Data Analysis and Healthcare, 201
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