Argamassas térmicas à base de cal

Actualmente, as preocupações com o consumo energético dos edifícios são cada vez maiores. Surgindo desta forma, a necessidade de incorporação de materiais em produtos de construção que visem a melhoria da eficiência energética dos edifícios. Portanto, a utilização de materiais de mudança de fase surge como uma possível solução para tentar solucionar, ou pelo menos minimizar, os enormes consumos energéticos associados aos edifícios. Este estudo visa o conhecimento da influência da incorporação de microcápsulas de materiais de mudança de fase (PCM) em argamassas à base de cal, devendo estas possuir um compromisso entre a trabalhabilidade, resistência mecânica e aparência estética

Properties of lime based thermal mortars

[Excerpt] Nowadays, major part of residential buildings electricity consumption is used for space heating and cooling, varying greatly during day and night and leading to differentiate tariffs. The shift, to off-peak periods, of this consumption presents a clear economical advantage and it can be achieved through energy thermal storage. Latent heat thermal energy storage, through the incorporation of PCM, presents the following advantages: narrow the gap between the peak and off-peak loads, levelling the electricity demand, decreasing the load on the network and eventual supply failure; reduce operation costs by shifting the electrical consumption from peak periods to off-peak periods; contribute to the interior thermal comfort in buildings, by using and storing solar energy (for space heating in winter) and storing natural cooling by ventilation at night during the summer, thus reducing electricity use for heating and cooling [1,2].The benefits to the comfort inside buildings appear during the change of the PCM. The transferences of energy that occur during the transitions solid-liquid and liquid-solid are generally the most used to help the acclimatization of the building. For that reason the PCM must be microencapsulated. The exterior of the microcapsules is made with a polymer [1,2]

Novos materiais de construção com tecnologias avançadas

Este artigo pretende apenas dar um contributo, assinalando alguns exemplos em que se tem vindo a trabalhar e que refletem o uso de tecnologias avançadas na formulação e funcionalidade de materiais de construção tradicionais. Um exemplo claro é o uso de aditivos que induzem novas funções e que muitos deles pertencem ao grupo denominado como nanomateriais. A sua adição coloca quase sempre problemas de incorporação e que requerem um trabalho de ajuste das formulações e comportamentos no estado fresco ou endurecido. Este trabalho de investigação é muitas vezes essencial para a otimização das funções que se pretendem que os materiais de construção venham a demonstrar. Neste grupo de investigação, resultante da cooperação entre centros de I&D e empresas em projetos de colaboração diversos ao longo dos últimos anos, tem-se vindo a focar na introdução de novas funções em materiais de construção tradicionais, para que ganhem um papel ativo em domínios como o do conforto térmico ou da qualidade ambiental, dois pilares essenciais para uma construção mais sustentável

Development of dark Ti(C,O,N) coatings prepared by reactive sputtering

Accepted manuscriptDirect current reactive magnetron sputtering was implemented to successfully deposit dark Ti(C,O,N) thin films on silicon substrates. A titanium target was sputtered while a mixture of oxygen and nitrogen was injected into the deposition chamber, independently from an acetylene source. The deposition parameters were chosen as a function of pre-existing knowledge about sputtered Ti–O–N and Ti–C–O films. Tuning the oxygen/(nitrogen+carbon) ratio allowed obtaining a large spectrum of properties. In particular, the colour of the films was characterized by spectral reflectance spectroscopy, and expressed in the CIE 1976 L*a*b* colour space. An accurate control of the reactive gas mixture flow rate allowed obtaining intrinsic, stable and attractive dark colour for decorative applications. Surprisingly, the coatings with the lowest content of carbon and the highest content of oxygen presented the darkest tones. Composition analysis by electron probe microanalysis was done to quantify the titanium and metalloid concentrations in the films. X-ray diffraction experiments revealed the evolution of the film structure from a fcc structure for the lowest (O2+N2) flow rates to an amorphous one for the highest flow rates.Fundação para a Ciência e Tecnologia (FCT) - SFRH/BPD/27114/2006 and PTDC/CTM/69362/2006. CRUP (Acção Integrada Luso-francesa No. F-2307). GRICES/CNRS collaboration (Proc. 4.1.1 França

Screening of sustainable groundwater sources for integration into a regional drought-prone water supply system

This paper reports on the qualitative and quantitative screening of groundwater sources for integration into the public water supply system of the Algarve, Portugal. The results are employed in a decision support system currently under development for an integrated water resources management scheme in the region. Such a scheme is crucial for several reasons, including the extreme seasonal and annual variations in rainfall, the effect of climate change on more frequent and long-lasting droughts, the continuously increasing water demand and the high risk of a single-source water supply policy. The latter was revealed during the severe drought of 2004 and 2005, when surface reservoirs were depleted and the regional water demand could not be met, despite the drilling of emergency wells. For screening and selection, quantitative criteria are based on aquifer properties and well yields, whereas qualitative criteria are defined by water quality indices. These reflect the well’s degree of violation of drinking water standards for different sets of variables, including toxicity parameters, nitrate and chloride, iron and manganese and microbiological parameters. Results indicate the current availability of at least 1100 l s−1 of high quality groundwater (55% of the regional demand), requiring only disinfection (900 l s−1) or basic treatment, prior to human consumption. These groundwater withdrawals are sustainable when compared to mean annual recharge, considering that at least 40% is preserved for ecological demands. A more accurate and comprehensive analysis of sustainability is performed with the help of steady-state and transient groundwater flow simulations, which account for aquifer geometry, boundary conditions, recharge and discharge rates, pumping activity and season. ([email protected]) ality. They permit an advanced analysis of present and future scenarios and show that increasing water demands and decreasing rainfall will make the water supply system extremely vulnerable, with a high risk of groundwater salinization and ecosystem degradation

Qualidade de frutos de laranjeira 'pêra' em combinação com diferentes porta-enxertos em Capitão Poço - PA.

O fruto da laranjeira (Citrus sinensis) é reconhecido atualmente como uma das principais frutas de exportação do agronegócio brasileiro. Por se tratar de uma planta de fácil adaptabilidade às condições variadas de solo e clima, e por conta disso, acham-se pomares citrícolas em várias regiões do Brasil. Diante disso, objetivou-se avaliar os atributos físicos e físico-químicos de frutos de laranja cultivar ?Pêra? combinada com diferentes porta-enxertos em Capitão Poço-PA. O delineamento foi Inteiramente Casualizado (DIC) organizados em seis tratamentos com quatro repetições, sendo dez plantas por repetição. Os tratamentos compostos por seis variedades de porta-enxerto sob copa de laranjeira ?Pêra? foram coletados, de forma aleatória, 20 frutos por repetição, totalizando 80 frutos de cada tratamento. Os parâmetros analisados foram: Diâmetros (longitudinais e equatoriais), Rendimento do suco, pH, Sólidos Solúveis Totais (ºBrix), Acidez Total Titulável e Ratio. Os dados obtidos não apresentaram diferença significativa quanto ao teste de média Tukey a 5% de probabilidade

Patterns of biomechanical demands are associated with musculoskeletal pain in the beginning of professional life: a population-based study

Objectives This study aimed to describe patterns of occupational biomechanical demands in the beginning of professional life and to quantify their association with the presence and intensity of regional musculoskeletal pain. Methods Cross-sectional data from 21-year-old participants were collected during the third wave of the EPITeen cohort study (N=1733, 37.5% were workers). Ten different work-related biomechanical tasks were characterized. Latent class analysis was conducted to identify empirical patterns of occupational biomechanical demands. The presence and intensity of regional musculoskeletal pain in the previous year were also evaluated. Results Four patterns of occupational biomechanical demands were found: “low demands”, “sitting demands”, “repetitive and asymmetric demands”, and “high and vibrational demands”. When compared to workers with low demands, those with repetitive and asymmetric demands or high and vibrational demands presented 80% higher adjusted odds ratio (ORadj) of reporting neck/shoulder pain. High and vibrational demands occupations were significantly associated with upper-/lower-back pain in comparison to low demands [ORadj 1.80, 95% confidence interval (95% CI%) 1.09–2.96]. In addition, workers with sitting demands were more likely to report any or severe upper-/lower-back pain [ORadj 1.56 (95% CI 0.99–2.45) and 1.66 (95% CI 1.03–2.66), respectively] when compared to those with low demands. Conclusions Patterns of high work-related physical demands were associated with the presence of neck/shoulder pain and severity of upper-/lower-back pain. This emphasizes that even short-term biomechanical exposures at the workplace may be involved in the etiology of musculoskeletal complaints

Development and validation of psoriatic arthritis switch quality assessment tool (PASQAL)-an outcomes measurement tool to assess the quality of biologic switch decisions in psoriatic arthritis

Background: Switching between biologic therapies is a recommended strategy for Psoriatic Arthritis (PsA) patients that show an insufficient response or adverse events. Although the choice of the subsequent biologic may be dependent on many factors, assessing the quality of the switch decision is of utmost relevance. Objectives: To develop and validate two outcomes measurement tools (for patients with peripheral and axial PsA phenotypes) that address the quality of treatment decisions in PsA regarding the switch of biologic therapies in clinical practice. Methods: A Task Force and an Expert Panel were specifically assembled for this purpose. The Psoriatic Arthritis Switch Quality Assessment tool (PASQAL) de-velopment comprised a modified-Delphi method in a four-step procedure: 1) literature search and experts' opinion collection about quality indicators for PsA management; 2) Delphi design to address the development of the measurement tool; 3) three Delphi questionnaire rounds; 4) final consensus meeting. This phase resulted in the definition of two measurement tools, one to evaluate the quality of biologic switch in peripheral (pPASQAL) and another one in axial PsA (axPASQAL). For the validation of PASQAL, 12 experienced rheumatologists were asked to evaluate and classify the biologic switch of 80 clinical cases (40 with predominant peripheral and 40 with predominant axial PsA). Clinical judgement was defined to be the "gold standard" against which the performance of PASQAL was assessed. The results were used to assess tools' performance (sensitivity/specificity analysis) and the agreement between the tools and the gold standard (Cohen's kappa). Results: PASQAL consists of 6 domains (joint disease activity, dactylitis, enthesis, physical function, quality of life, and skin and nail manifestations), respective instruments and thresholds. The classification of the biologic switch was divided into three quality levels: "Good", based on treat-to-target thresholds; "Mode-rate", based on improvement from baseline; and the remaining as "Insufficient". pPASQAL was found to be highly sensitive (92%) with the "Good" quality level and specific (97%) with the "Insufficient" quality le vel. Whilst axPASQAL showed overall higher sensitivity and specificity for all quality levels, as well as a higher level of agreement between the tool and the gold standard than pPASQAL (k=0.87 vs k=0.71). Conclusion: PASQAL was developed and showed good criterion validity for the evaluation of the quality of switch in both peripheral and axial PsA phenotypes. These tools may be used in research as well as in clinical practice, to support rheumatologists in making more informed therapeutic decisions.publishersversionpublishe