1,343 research outputs found

    An ideal IoT solution for real-time web monitoring

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    For the internet of things (IoT) to fully emerge, it is necessary to design a suitable system architecture and specific protocols for this environment. The former to provide horizontal solutions, breaking away the current paradigm of silos solutions, and thus, allowing the creation of open and interoperable systems; while the latter will offer efficient and scalable communications. This paper presents the latest standards and ongoing efforts to develop specific protocols for IoT. Furthermore, this paper presents a new system, with the most recent standards for IoT. Its design, implementation and evaluation will be also described. The proposed system is based on the latest ETSI M2M specification (ETSI TC M2M in ETSI TS 103 093 V2.1.1.http://www.etsi.org/deliver/etsi_ts/103000_103099/103093/02.01.01_60/ts_103093v020101p.pdf, 2013b) and the MQTT protocol (IBM, Eurotech in MQTT V3.1 Protocol Specification pp 1-42, http://public.dhe.ibm.com/software/dw/webservices/ws-mqtt/MQTT_V3.1_Protocol_Specific. pdf, 2010). With this solution it is possible to show how we can create new applications to run over it and the importance of designing specifically tailored for IoT communication protocols in order to support real-time applications.- This project was funded by Fundo Europeu de Desenvolvimento Regional (FEDER), by Programa Operacional Factores de Competitividade (POFC) - COMPETE and by Fundacao para a Ciencia eTecnologia, on the Scope of projects: PEstC/EEI/UI0319/2015 and PEstC/EEI/UI0027/2015. This paper is a result of the project "SmartEGOV: Harnessing EGOV for Smart Governance (Foundations, methods, Tools) / NORTE-01-0145-FEDER-000037", supported by Norte Portugal Regional Operational Programme(NORTE2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (EFDR).info:eu-repo/semantics/publishedVersio

    Use of chemical fractionation to understand partitioning of biomass ash constituents during co-firing in fluidized bed combustion

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    Three species of biomass origin (straw pellets, olive cake and wood pellets) and two coals from different countries (Coal Polish and Coal Colombian) have been studied to understand the fate of their ash forming matter during the combustion process and to investigate the influence of co-firing biomass with coal. Three different approaches to investigate the ash behaviour were employed: (1) chemical fractionation analysis to evaluate the association/reactivity of ash forming elements in the fuels as a prediction tool, (2) establishment of elements partitioning in ash streams produced in the combustion and co-combustion trials, and (3) evaluation of enrichment factors of elements in the ash streams. The chemical fractionation analysis was applied to all fuels used to evaluate how the association/reactivity of elements making up ash may influence their behaviour during combustion. Combustion tests were carried out on a pilot scale fluidized bed combustor (FBC). Four ash streams were obtained at different locations. The uncertainty of measurements was estimated allowing a critical evaluation of mass balances over the combustion system and the partitioning of elements in the ash streams. The enrichment factors of elements in the several ash streams were estimated, incorporating uncertainties associated with analytical measurements. Results obtained showed that for FBC the relation between the chemical fractionation and the experimental partitioning is strongly affected by elutriation of particles. The element enrichment factor estimated for each ash stream, using Al as a reference element, revealed better correlations with the elements reactivity obtained by chemical fractionation because it overcomes particles elutriation effects. Nevertheless, it was observed that the reactivity estimated by chemical fractionation could not be solely interpreted as tendency of the elements to volatilize on FBC system, as reaction in bed zone of boiler may also occur retaining reactive elements

    Developing a model for cystic fibrosis sociomicrobiology based on antibiotic and environmental stress

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    Cystic fibrosis (CF) infections are invariably biofilm-mediated and polymicrobial, being safe to assume that a myriad of factors affects the sociomicrobiology within the CF infection site and modulate the CF community dynamics, by shaping their social activities, overall functions, virulence, ultimately affecting disease outcome. This work aimed to assess changes in the dynamics (particularly on the microbial composition) of dual-/three-species biofilms involving CF-classical (Pseudomonas aeruginosa) and unusual species (Inquilinus limosus and Dolosigranulum pigrum), according to variable oxygen conditions and antibiotic exposure. Low fluctuations in biofilm compositions were observed across distinct oxygen environments, with dual-species biofilms exhibiting similar relative proportions and P. aeruginosa and/or D. pigrum populations dominating three-species consortia. Once exposed to antibiotics, biofilms displayed high resistance profiles, and microbial compositions, distributions, and microbial interactions significantly challenged. The antibiotic/oxygen environment supported such fluctuations, which enhanced for three-species communities. In conclusion, antibiotic therapy hugely disturbed CF communities dynamics, inducing significant compositional changes on multispecies consortia. Clearly, multiple perturbations may disturb this dynamic, giving rise to various microbiological scenarios in vivo, and affecting disease phenotype. Therefore, an appreciation of the ecological/evolutionary nature within CF communities will be useful for the optimal use of current therapies and for newer breakthroughs on CF antibiotherapy.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/ BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER006684). The authors also acknowledge the financial support provided by FCT through the projects: PTDC/SAU-ESA/646091/2006/ FCOMP01-0124-FEDER-007480FCT; strategic project PEst-OE/EQB/LA0023/2013; “BioHealth – Biotechnology and Bioengineering approaches to improve health quality”, Ref. NORTE-07-0124-FEDER-000027, cofunded by the Programa Operacional Regional do Norte (ON.2–O Novo Norte), QREN, FEDER; RECI/BBB-EBI/0179/2012 – Consolidating Research Expertise and Resources on Cellular and Molecular Biotechnology at CEB/IBB, FCOMP-01-0124-FEDER-027462, FEDER; and the DNA mimics project PIC/IC/82815/2007. The FCT BPD fellowship of Susana P. Lopes SFRH/BPD/95616/2013 and the support of the COST-Action TD1004:Theragnostics for imaging and therapy is also acknowledged.info:eu-repo/semantics/publishedVersio

    Uncertainty estimation to evaluate mass balances on a combustion system 

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    Mass balances of ash and potassium for a fluidized bed combustor were performed incorporating measurement uncertainties. The total output mass of ash or a chemical element should be equal to the mass in the input fuel; however, this is not often achieved. A realistic estimation of recovery uncertainty can support the reliability of a mass balance. Estimation of uncertainty helps to establish a reliable evaluation of the recovery ratio of ash mass and elemental mass. This may clarify whether any apparent lack in closing the mass balance can be attributed to uncertainties. The evaluation of measurement uncertainty for different matrices, namely coal, biomass, sand and ashes from different streams was based on internal quality control data and external quality control data, namely analysis of samples from proficiency tests or use of a certified reference material. The evaluation of intermediate precision and trueness allowed the estimation of measurement uncertainty. Due to the different physic and chemical characteristics of the studied matrices, the uncertainty of precision was evaluated using R-charts of data obtained from the analysis of duplicates for the majority of samples. This allowed evaluating sample heterogeneity effects. The instrumental acceptance criterion was also considered and included in the combined uncertainty. The trueness was evaluated using data from several proficiency tests and from analysis of a certified reference material or sample spiking. Statistically significant bias was included

    Quantitative assessment of individual populations within polymicrobial biofilms

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    The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.Selecting appropriate tools providing reliable quantitative measures of individual populations in biofilms is critical as we now recognize their true polymicrobial and heterogeneous nature. Here, plate count, quantitative real-time polymerase chain reaction (q-PCR) and peptide nucleic acid probe-fluorescence in situ hybridization (PNA-FISH) were employed to quantitate cystic fibrosis multispecies biofilms. Growth of Pseudomonas aeruginosa, Inquilinus limosus and Dolosigranulum pigrum was assessed in dual- and triple-species consortia under oxygen and antibiotic stress. Quantification methods, that were previously optimized and validated in planktonic consortia, were not always in agreement when applied in multispecies biofilms. Discrepancies in culture and molecular outcomes were observed, particularly for triple-species consortia and antibiotic-stressed biofilms. Some differences were observed, such as the higher bacterial counts obtained by q-PCR and/or PNA-FISH (?4 log10 cells/cm2) compared to culture. But the discrepancies between PNA-FISH and q-PCR data (eg D. pigrum limited assessment by q-PCR) demonstrate the effect of biofilm heterogeneity in method's reliability. As the heterogeneity in biofilms is a reflection of a myriad of variables, tailoring an accurate picture of communities? changes is crucial. This work demonstrates that at least two, but preferentially three, quantification techniques are required to obtain reliable measures and take comprehensive analysis of polymicrobial biofilm-associated infections.The authors thank the financial support from the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE2020 – Programa Operacional Competitividade e Internacionalização (POCI-01–0145-FEDER-006684) and BioTecNorte operation (NORTE01-0145-FEDER-000004) funded by the European Regional Development Fund (ERDF) under the scope of Norte2020 - Programa Operacional Regional do Norte. This work was also the result of the projects: (i) POCI01-0145-FEDER-006939 (Laboratory for Processing Engineering, Environment, Biotechnology and Energy – UID/EQU/00511/2013) funded by the ERDF, through COMPETE2020 and by national funds, through FCT; (ii) NORTE-01-0145-FEDER-000005 – LEPABE-2-ECO-INNOVATION, supported by North Portugal Regional Operational Programme (NORTE2020), under the Portugal2020 Partnership Agreement, through the ERDF; (iii) Coded-FISH PTDC/DTP-PIC/4562/2014/16678; (iv) POCI-01-0145-FEDER-029841, through COMPETE2020 - Programa Operacional Competitividade e Internacionalização and by national funds, through FCT). Also, the fellowship of Susana P. Lopes SFRH/BPD/95616/2013 is acknowledged. The authors would also like to thanks to Dr Michael Surette (Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, ON, Canada) for kindly providing the I. limosus strain used in this study.info:eu-repo/semantics/publishedVersio

    Evaluation of slagging and fouling tendency during biomass co-firing with coal in a fluidized bed

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    Over the last decades, several indices based on ash chemistry and ash fusibility have been used to predict the ash behaviour during coal combustion, namely, its tendency for slagging and fouling. However, due to the physicalechemical differences between coals and biomass, in this work only the applicability of an ash fusibility index (AFI) to the combustion and co-combustion of three types of biomass (straw pellets, olive cake and wood pellets) with coals was evaluated. The AFI values were compared with the behaviour of ash during combustion in a pilot fluidized bed and a close agreement was observed between them. For a better understanding of the mechanisms associated with bed ash sintering, they were evaluated by SEM/EDS and the elements present on the melted ash were identified. Evidences of different sintering mechanisms were found out for the fruit biomass and herbaceous biomass tested, depending on the relative proportions of problematic elements. The particles deposited on a fouling probe inserted in the FBC were analyzed by XRD and the differences between the compounds identified allowed concluding that the studied biomasses present different tendencies for fouling. Identification of KCl and K2SO4 in the deposits confirmed the higher tendency for fouling of fruit biomass tested rather than wood pellets

    Applying Prolog to Develop Distributed Systems

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    Development of distributed systems is a difficult task. Declarative programming techniques hold a promising potential for effectively supporting programmer in this challenge. While Datalog-based languages have been actively explored for programming distributed systems, Prolog received relatively little attention in this application area so far. In this paper we present a Prolog-based programming system, called DAHL, for the declarative development of distributed systems. DAHL extends Prolog with an event-driven control mechanism and built-in networking procedures. Our experimental evaluation using a distributed hash-table data structure, a protocol for achieving Byzantine fault tolerance, and a distributed software model checker - all implemented in DAHL - indicates the viability of the approach

    Evolution of squeezed states under the Fock-Darwin Hamiltonian

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    We develop a complete analytical description of the time evolution of squeezed states of a charged particle under the Fock-Darwin Hamiltonian and a time-dependent electric field. This result generalises a relation obtained by Infeld and Pleba\'nski for states of the one-dimensional harmonic oscillator. We relate the evolution of a state-vector subjected to squeezing to that of state which is not subjected to squeezing and for which the time-evolution under the simple harmonic oscillator dynamics is known (e.g. an eigenstate of the Hamiltonian). A corresponding relation is also established for the Wigner functions of the states, in view of their utility in the analysis of cold-ion experiments. In an appendix, we compute the response functions of the FD Hamiltonian to an external electric field, using the same techniques as in the main text
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