1,755 research outputs found

    PNNARMA model: an alternative to phenomenological models in chemical reactors

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    This paper is focused on the development of non-linear neural models able to provide appropriate predictions when acting as process simulators. Parallel identification models can be used for this purpose. However, in this work it is shown that since the parameters of parallel identification models are estimated using multilayer feed-forward networks, the approximation of dynamic systems could be not suitable. The solution proposed in this work consists of building up parallel models using a particular recurrent neural network. This network allows to identify the parameter sets of the parallel model in order to generate process simulators. Hence, it is possible to guarantee better dynamic predictions. The dynamic behaviour of the heat transfer fluid temperature in a jacketed chemical reactor has been selected as a case study. The results suggest that parallel models based on the recurrent neural network proposed in this work can be seen as an alternative to phenomenological models for simulating the dynamic behaviour of the heating/cooling circuits.Publicad

    Effects of deformation on the β -decay patterns of light even-even and odd-mass Hg and Pt isotopes

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    14 pags.; 16 figs.; 2 tabs.; PACS number(s): 21.60.Jz, 23.40.−s, 27.70.+q, 27.80.+w© 2015 American Physical Society. Bulk and decay properties, including deformation energy curves, charge mean square radii, Gamow-Teller (GT) strength distributions and β-decay half-lives are studied in neutron-deficient even-even and odd-A Hg and Pt isotopes. The nuclear structure is described microscopically from deformed quasiparticle random-phase approximation calculations with residual interactions in both particle-hole and particle-particle channels, performed on top of a self-consistent deformed quasiparticle Skyrme Hartree-Fock basis. The observed sensitivity of the not-yet-measured GT strength distributions to deformation is proposed as an additional complementary signature of the nuclear shape. The β-decay half-lives resulting from these distributions are compared to experiment to demonstrate the ability of the method.This work was supported by Ministerio de Economíıa y Competitividad (Spain) under Contract No. FIS2011–23565 and the Consolider–Ingenio 2010 Programs CPAN CSD2007-00042.Peer Reviewe

    Complexation Study of Alkali Metal Ions by Crown Ether Derivatives in Nonaqueous Solvents by Potentiometric Methods

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    The formation and stability of alkali metal complexes with crown ethers containing an anthraquinone unit has been investigated in methanol and acetonitrile solutions by potentiometric methods. Complexes of 1:1 stoichiometry were observed for all the studied systems; 2:1 complexes were only detected for the larger alkali cations (Rb+ and Cs+) and with the ligand with the larger macrocyclic cavity (AQ21C7). The 1:1 complexes with the highest stability are formed by K+ ion with the AQ18C6 ligand and by Cs+ ion with the AQ21C7 ligand. In the alkali cation group and in both solvents, the stability of the 1:1 complexes was found to vary in the following order, Li+ Rb+ > Cs+ with AQ18C6 ligand and Li+ < Na+ < K+ < Rb+ < Cs+ with AQ21C7 ligand. The stability of the complexes of AQ21C7 is smaller than those of their AQ18C6 analogues. The stability of the silver complexes of AQ18C6 and AQ21C7 was found to be smaller than that of the alkali metal complexes of comparable size. The incorporation of an anthraquinone unit in crown ethers induces some loss of complexation stability for all cations, but the cation selectivity is not changed. The results obtained are analysed and discussed regarding the effects of the relative sizes of the cations and macrocyclic cavity of the ligands, solvating ability of the solvents towards the cation and influence of the anthraquinone unit

    Mitochondrial dysfunction promoted by Porphyromonas gingivalis lipopolysaccharide as a possible link between cardiovascular disease and periodontitis

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    Oxidative stress is one of the factors that could explain the pathophysiological mechanism of inflammatory conditions that occur in cardiovascular disease (CVD) and periodontitis. Such inflammatory response is often evoked by specific bacteria, as the lipopolysaccharide (LPS) of Porphyromonas gingivalis is a key factor in this process. The aim of this research was to study the role of mitochondrial dysfunction in peripheral blood mononuclear cells (PBMCs) from periodontitis patients and to evaluate the influence of LPS on fibroblasts to better understand the pathophysiology of periodontitis and its relationship with CVD. PBMCs from patients showed lower CoQ10 levels and citrate synthase activity, together with high levels of ROS production. LPS-treated fibroblasts provoked increased oxidative stress and mitochondrial dysfunction by a decrease in mitochondrial protein expression, mitochondrial mass, and mitochondrial membrane potential. Our study supports the hypothesis that LPS-mediated mitochondrial dysfunction could be at the origin of oxidative stress in periodontal patients. Abnormal PBMC performance may promote oxidative stress and alter cytokine homeostasis. In conclusion, mitochondrial dysfunction could represent a possible link to understanding the interrelationships between two prominent inflammatory diseases: periodontitis and CV

    Demand response performance and uncertainty: A systematic literature review

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    The present review has been carried out, resorting to the PRISMA methodology, analyzing 218 published articles. A comprehensive analysis has been conducted regarding the consumer's role in the energy market. Moreover, the methods used to address demand response uncertainty and the strategies used to enhance performance and motivate participation have been reviewed. The authors find that participants will be willing to change their consumption pattern and behavior given that they have a complete awareness of the market environment, seeking the optimal decision. The authors also find that a contextual solution, giving the right signals according to the different behaviors and to the different types of participants in the DR event, can improve the performance of consumers' participation, providing a reliable response. DR is a mean of demand-side management, so both these concepts are addressed in the present paper. Finally, the pathways for future research are discussed.This article is a result of the project RETINA (NORTE-01-0145- FEDER-000062), supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). We also acknowledge the work facilities and equipment provided by GECAD research center (UIDB/00760/2020) to the project team, and grants CEECIND/02887/2017 and SFRH/BD/144200/2019.info:eu-repo/semantics/publishedVersio

    A possible Tsunami deposit associated to the CE 1755 Lisbon earthquake on the Western Coast of Portugal

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    The CE 1755 Lisbon tsunami was the largest historical tsunami to affect the Atlantic coasts of Europe and North Africa. This study presents the results obtained from the application of different sedimentological techniques (e.g., grain size, morphoscopy, microtextural analysis, geochemistry, radiocarbon dating) on sediments retrieved from the Alcabrichel River alluvial plain (of about 500 m far away from its mouth and approximatively 50 km northwest of Lisbon, Portugal). The results allowed the identification of a sandy layer that was associated with the CE 1755 tsunami. Furthermore, a new microtextural semi-quantitative classification was applied to enhance the identification of extreme marine inundation deposits. Based on sedimentological data, three different tsunami inundation phases were identified, including two inundations and a likely backwash. This innovative work offers physical evidence of the spatial presence of the CE 1755 tsunami event on the western coast of Europe. It also enables a reconstruction of tsunami inundation dynamics, with two flooding waves and an interspersed backwash.info:eu-repo/semantics/publishedVersio

    Phase transitions and statistical mechanics for BPS Black Holes in AdS/CFT

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    Using the general framework developed in hep-th/0607056, we study in detail the phase space of BPS Black Holes in AdS, for the case where all three electric charges are equal. Although these solitons are supersymmetric with zero Hawking temperature, it turns out that these Black Holes have rich phase structure with sharp phase transitions associated to a corresponding critical generalized temperature. We are able to rewrite the gravity variables in terms of dual CFT variables and compare the gravity phase diagram with the free dual CFT phase diagram. In particular, the elusive supergravity constraint characteristic of these Black Holes is particulary simple and in fact appears naturally in the dual CFT in the definition of the BPS Index. Armed with this constraint, we find perfect match between BH and free CFT charges up to expected constant factors.Comment: 14 pages, 5 figures, corrected typos and references adde

    Eucalyptus microfungi known from culture. 1. Cladoriella and Fulvoflamma genera nova, with notes on some other poorly known taxa

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    A study of microfungi associated with living Eucalyptus leaves and leaf litter revealed several novel and interesting taxa. Cladoriella eucalypti gen. et sp. nov. is described as a Cladosporium-like genus associated with litter collected in South Africa, while Fulvoflamma eucalypti gen. et. sp. nov. is newly described from leaf litter collected in Spain. Beta-conidia are newly reported for species of Pestalotiopsis, namely Pestalotiopsis disseminata in New Zealand, and a Pestalotiopsis sp. from Colombia. Satchmopsis brasiliensis is reported from litter in Colombia and Indonesia, while Torrendiella eucalypti is reported from leaf litter in Indonesia, and shown to have a Sporothrix-like anamorph. Leptospora rubella is reported from living Eucalyptus leaves in Colombia, where it is associated with leaf spots of Mycosphaerella longibasalis, while Macrohilum eucalypti is reported from leaf spots of Eucalyptus in New Zealand
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