585 research outputs found
Erratum: Martins, M.S., et al. Wideband and wIde beam polyvinylidene difluoride (PVDF) acoustic transducer for broadband underwater. Sensors 2019, 19, 3991
The authors wish to make the following erratum to this paper [...].info:eu-repo/semantics/publishedVersio
Nanotubos de carbono para processos de tratamento de águas
Oxidantes como o oxigénio molecular, o ozono e o peróxido de hidrogénio são utilizados nos
tratamentos de águas residuais por via quÃmica oxidativa podendo atuar por si próprios, ou ser
ativados por meio de um catalisador, ou fotocatalisador, adequado. Sendo os tratamentos
quÃmicos processos definitivos por natureza, é possÃvel apontar à mineralização completa dos
poluentes presentes. Contudo, raramente é esse o caso, quando se procura uma solução
racional do ponto de vista económico. No caso de efluentes industriais recorre-se muitas vezes a tratamentos diferenciados, com vista a uma degradação oxidativa parcial
On requirements engineering for reactive systems: a formal methodology
This paper introduces a rigorous methodology for requirements specification of systems that react to external stimulus and consequently evolve through different operational modes, providing, in each of them, different functionalities. The proposed methodology proceeds in three stages, enriching a simple state- machine with local algebraic specifications. It resorts to an expressive variant of hybrid logic which is latter translated into first-order to allow for ample automatic tool support
A Lista Top 100
"Evitar a extinção das espécies é um dos maiores desafios actuais da ciência da conservação. A magnitude da perda de espécies é hoje tão importante que alguns autores defendem que estamos a ser testemunhas da sexta grande extinção na história da vida (Leakey & Lewin, 1995). De facto, no nosso planeta desta vez é a acção devastadora do Homem a força motriz que está a alterar habitats, a colocar em risco ecossistemas, e a extinguir inúmeras espécies, muitas delas desconhecidas para a ciência (Lawton & May, 1995; Pimm et al., 1995, 1996; Chapin et al., 2000). Durante os últimos séculos estas extinções tem sido muito significativas nas ilhas de todo o mundo (Reid & Miller, 1989; Lawton & May, 1995; Sadler, 1999; Steadman & Martin, 2003), o que tem estimulado o debate sobre a questão se os endemismos insulares são intrinsecamente mais sensÃveis à s ameaças do que as formas continentais (Manne et al., 1999; Sax et al., 2002; Frankham, 2005). Contudo embora não pareça claro que assim seja (Manne & Pimm, 2001; Biber, 2002), o facto é que as ilhas por serem territórios com muitos taxa endémicos de distribuição reduzida a espaços limitados e, como consequência disso, com poucas possibilidades de escapar a uma eventual ameaça –como por exemplo a introdução de um novo predador–, tem o risco de extinção aumentado (Duncan & Blackburn, 2007). Evidências mostram igualmente que nas ilhas o número de espécies de plantas vasculares não nativas tem subido mais do que a extinção do número de espécies nativas mas que nas aves as extinções igualam o ganho de espécies exóticas (Sax et al., 2002). O facto é que, independentemente da maior ou menor propensão ao desaparecimento das espécies insulares, as consequências devastadoras das ameaças externas nos territórios isolados levam a que as extinções nas ilhas sejam mais frequentes do que nos espaços abertos continentais (Quammen, 1997). [...]
A perspectiva Macaronésica
"As 100 espécies seleccionadas como prioritárias para a gestão na Macaronésia europeia (i.e., Açores, Madeira, Selvagens e Canárias) são maioritariamente das Canárias (51 taxa), em segundo lugar do arquipélago da Madeira (26 taxa) e em terceiro lugar do arquipélago dos Açores (23 taxa). Esta distribuição é apenas mais ou menos concordante com a riqueza relativa das três regiões, já que estão registadas apenas 420 espécies endémicas para os Açores (Borges et al., 2005, 2008a), 1284 espécies endémicas para os arquipélagos da Madeira e Selvagens (Borges et al., 2008b) e 3572 espécies endémicas para as ilhas Canárias (MartÃn et al., 2005). A lista "Top 100" inclui taxa da flora e da fauna dos três arquipélagos macaronésicos acima referidos. O grupo dominante, ao nÃvel do filo ou da divisão, é o das fanerogâmicas ou plantas com flor, no qual se incluem 66 taxa, seguido dos artrópodes, representados por 17 taxa. A distribuição por arquipélagos é desigual, e embora este padrão global se repita entre as espécies da Madeira e das Canárias, no caso dos Açores isso não sucede: o grupo mais numeroso é de longe o dos artrópodes, que compreende 12 dos 23 taxa selecionados"
Evaluating the forced oscillation technique in the detection of early smoking-induced respiratory changes
<p>Abstract</p> <p>Background</p> <p>Early detection of the effects of smoking is of the utmost importance in the prevention of chronic obstructive pulmonary disease (COPD). The forced oscillation technique (FOT) is easy to perform since it requires only tidal breathing and offers a detailed approach to investigate the mechanical properties of the respiratory system. The FOT was recently suggested as an attractive alternative for diagnosing initial obstruction in COPD, which may be helpful in detecting COPD in its initial phases. Thus, the purpose of this study was twofold: (1) to evaluate the ability of FOT to detect early smoking-induced respiratory alterations; and (2) to compare the sensitivity of FOT with spirometry in a sample of low tobacco-dose subjects.</p> <p>Methods</p> <p>Results from a group of 28 smokers with a tobacco consumption of 11.2 ± 7.3 pack-years were compared with a control group formed by 28 healthy subjects using receiver operating characteristic (ROC) curves and a questionnaire as a gold standard. The early adverse effects of smoking were adequately detected by the absolute value of the respiratory impedance (<it>Z4Hz</it>), the intercept resistance (<it>R0</it>), and the respiratory system dynamic compliance (<it>Crs, dyn</it>). <it>Z4Hz </it>was the most accurate parameter (Se = 75%, Sp = 75%), followed by <it>R0 </it>and <it>Crs, dyn</it>. The performances of the FOT parameters in the detection of the early effects of smoking were higher than that of spirometry (p < 0.05).</p> <p>Conclusion</p> <p>This study shows that FOT can be used to detect early smoking-induced respiratory changes while these pathologic changes are still potentially reversible. These findings support the use of FOT as a versatile clinical diagnostic tool in aiding COPD prevention and treatment.</p
Improving operational management of wastewater systems: a case study
Wastewater treatment facilities collecting wastewater from longstanding sewer networks of five municipalities in the Ave River basin (located in NW Portugal) are especially vulnerable to water inflows since they have considerable extensions of sewers installed in stream and riverbeds. TRATAVE, the company responsible for operating the system, designed and implemented a monitoring network to measure discharges along the entire drainage network and treatment facilities in order to reduce those water inflows. Several flow measurement devices were installed at strategic locations within the sewer network and integrated with a SCADA system responsible for its operation. A decision support system (DSS) is being implemented using the Delft-FEWS platform, integrating monitoring data and models. Based on monitored data and model results, an estimation of infiltration volumes during wet periods is presented. Moreover, the capabilities of the DSS are illustrated in: (i) location of manholes losses along sewer networks during wet periods; (ii) identification and location of unknown connections to the sewer network using wastewater balances; and (iii) design of a PID controller for a pumping station using on-line tank water level measurement. Acquired knowledge resulting from the DSS greatly improved the utility performance both in terms of economic revenue and environmental protectionThe authors thank TRATAVE for the financial support in
the installation of measurement devices, the first author’s scholarship for PhD tuition fees, and in making available
the monitoring data used in this research
A DSS for operational management of wastewaters under uncertain conditions
Wastewater treatment facilities of the Ave River basin (located in NW Portugal) are especially vulnerable to infiltration since they present considerable extensions of sewers installed in streams and rivers and collect wastewaters from longstanding sewer networks of five municipalities. The operational management of this complex system involves decision variables such as the selection of the treatment plant where collected wastewater will be treated, with implications for pumped volumes and consequent energy consumption. Aiming to reduce these inflows and increase the management performance of TRATAVE, the company responsible for operating the system, a monitoring network that includes the entire drainage network and treatment facilities operated by the company was designed and implemented. Several flow measurement devices were installed at strategic locations within the sewer network and integrated with a SCADA system responsible for its operation. All measured data was organized in databases. This monitoring platform will support the implementation of a decision support system (DSS) based on a hydrological model of the basin, a hydrodynamic model of the river network and the sewer network. The DSS is being implemented using the Delft-FEWS platform, integrating monitoring data and models. The DSS conceptual framework and the first results of the estimated infiltration volumes are presentedinfo:eu-repo/semantics/publishedVersio
Resources recovery in the dairy industry: bioelectricity production using a continuous microbial fuel cell
"Available online 19 April 2016"The increasing food demand and the exhaustion of non-renewable fuels provide new market opportunities in the agro-farming sector. Biological systems designed to add value to useless organic sub-products and to generate off-grid electricity may be one of the most interesting outcomes. Therefore, the capacity of some microorganisms to transfer electrons generated during organic carbon oxidation directly to an anode in a so-called microbial fuel cell (MFC) might be an asset in a sustainable management context. In this regard, the main goal of the present work was to evaluate the performance of a continuous MFC applied in a dairy industry. A maximum voltage of 576 mV was produced during continuous operation, corresponding to a power density of 92.2 mW·m-2 or 1.9 W·m-3. MFC was able to remove 1298±617 mg·L-1 of chemical oxygen demand (COD) at a hydraulic retention time of 8.4 h, and the maximum COD removal (63±5 %) was achieved after 20 days of continuous operation. In addition, the coulombic efficiency average was around 10.5±10% with a maximum of 24.2±1.5%. In average, the MFC was able to extract a specific energy of 8.95×102 kWh·kg-1 COD with a maximum output of 20.53×102 kWh·kg-1 COD. In conclusion, the MFC technology is a valuable option for simultaneous wastewater treatment and energy recovery and deserves to be tested and scaled-up in the dairy industry.Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, Project RECI/BBB-EBI/0179/ 2012 (FCOMP-01-0124-FEDER-027462)COMPETE 2020 (POCI- 01-0145-FEDER-006684)Program POPH/ESF - SFRH/BPD/80528/201
Design of graphene-based TiO2 photocatalysts - A review
There is a recent increase in the interest of de-
signing high-performance photocatalysts using graphene-
based materials. This review gathers some important aspects
of graphene–TiO 2 , graphene oxide–TiO 2 , and reduced gra-
phene oxide–TiO 2 composites, which are of especial rele-
vance as next generation photocatalysts. The methods used
for the preparation of these materials, the associated mech-
anistic fundamentals, and the application of graphene-based
composites on the photocatalytic degradation of pollutants
are reviewed. Some structural, textural, and chemical prop-
erties of these materials and other photo-assisted applica-
tions, such as hydrogen production from water splitting and
dye-sensitized solar cells, are also briefly includedFinancial support for this work was provided by
the European Commission (Clean Water—grant agreement no 227017)
and by Fundação para a Ciência e a Tecnologia (FCT) and FEDER
under Program COMPETE, project FCOMP-01-0124-FEDER-022706
(Ref. FCT Pest-C/EQB/LA0020/2011) and FCOMP-01-0124-FEDER-
008442 (Ref. NANO/NTec-CA/0046/2007). Clean Water is a Collab-
orative Project co-funded by the Research DG of the European Com-
mission within the joint RTD activities of the Environment and NMP
Thematic Priorities. SMT and AMTS acknowledge financial support
from SFRH/BPD/74239/2010 and POCI/N010/2006, respectively
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