3,348 research outputs found

    Velocity fluctuations and population distribution in clusters of settling particles at low Reynolds number

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    A study on the spatial organization and velocity fluctuations of non Brownian spherical particles settling at low Reynolds number in a vertical Hele-Shaw cell is reported. The particle volume fraction ranged from 0.005 to 0.05, while the distance between cell plates ranged from 5 to 15 times the particle radius. Particle tracking revealed that particles were not uniformly distributed in space but assembled in transient settling clusters. The population distribution of these clusters followed an exponential law. The measured velocity fluctuations are in agreement with that predicted theoretically for spherical clusters, from the balance between the apparent weight and the drag force. This result suggests that particle clustering, more than a spatial distribution of particles derived from random and independent events, is at the origin of the velocity fluctuations.Comment: 13 pages, 8 figure

    Self-management of context-aware overlay ambient networks

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    Ambient Networks (ANs) are dynamically changing and heterogeneous as they consist of potentially large numbers of independent, heterogeneous mobile nodes, with spontaneous topologies that can logically interact with each other to share a common control space, known as the Ambient Control Space. ANs are also flexible i.e. they can compose and decompose dynamically and automatically, for supporting the deployment of cross-domain (new) services. Thus, the AN architecture must be sophisticatedly designed to support such high level of dynamicity, heterogeneity and flexibility. We advocate the use of service specific overlay networks in ANs, that are created on-demand according to specific service requirements, to deliver, and to automatically adapt services to the dynamically changing user and network context. This paper presents a self-management approach to create, configure, adapt, contextualise, and finally teardown service specific overlay networks

    Fast model predictive control for hydrogen outflow regulation in ethanol steam reformers

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    © 20xx IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.In the recent years, the presence of alternative power sources, such as solar panels, wind farms, hydropumps and hydrogen-based devices, has significantly increased. The reasons of this trend are clear: contributing to a reduction of gas emissions and dependency on fossil fuels. Hydrogen-based devices are of particular interest due to their significant efficiency and reliability. Reforming technologies are among the most economic and efficient ways of producing hydrogen. In this paper we consider the regulation of hydrogen outflow in an ethanol steam reformer (ESR). In particular, a fast model predictive control approach based on a finite step response model of the process is proposed. Simulations performed using a more realistic non-linear model show the effectiveness of the proposed approach in driving the ESR to different operating conditions while fulfilling input and output constraints.Peer ReviewedPostprint (author's final draft

    Energy Efficiency of Hybrid-Power HetNets: A Population-like Games Approach

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    In this paper, a distributed control scheme based on population games is proposed. The controller is in charge of dealing with the energy consumption problem in a Heterogeneous Cellular Network (HetNet) powered by hybrid energy sources (grid and renewable energy) while guaranteeing appropriate quality of service (QoS) level at the same time. Unlike the conventional approach in population games, it considers both atomicity and non-anonymity. Simulation results show that the proposed population-games approach reduces grid consumption by up to about 12% compared to the traditional best-signal level association policy.U.S. Air Force Office of Scientific Research FA9550-17-1-0259Ministerio de Cultura y Deporte DPI2016-76493-C3-3-RMinisterio de Economía y Empresa DPI2017-86918-

    Assessment of habitat quality and landscape connectivity for forest-dependent cracids in the Sierra Madre del Sur Mesoamerican biological corridor, Mexico

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    Assessing landscape connectivity allows us to identify critical areas that impede or facilitate the movement of organisms and their genes and to plan their conservation and management. In this article, we assessed landscape connectivity and ecological condition of the habitat patches of a highly biodiverse region in Chiapas, Mexico. We employed data of three cracid species with different characteristics in habitat use and mobility. The habitat map of each species was derived from a spatial intersection of the models of potential distribution and a high-resolution map of current land cover and land use. The ecological condition of vegetation types was evaluated using 75 field plots. Structure of landscape was estimated by fragmentation metrics, while functional connectivity was assessed using spatially explicit graph analysis. The extent of suitable habitat for Oreophasis derbianus, Penelopina nigra, and Penelope purpurascens correspond to 25%, 46%, and 55% of the study area (5,185.6 km2), respectively. Although the pine-oak forests were the most fragmented vegetation type, habitats of the three species were well connected, and only 4% to 9% of the fragments located on the periphery of the corridor had low connectivity. Landscape connectivity depends mainly on land uses with an intermediate and lower ecological condition (secondary forests and coffee agroforestry systems). Therefore, we suggest that in addition to promoting the improvement in connectivity in fragmented forests, conservation efforts should be aimed at preventing the conversion of mature forests into agricultural uses and maintaining agroforestry systems

    An Embedded System Design for Data Collection and Analysis for Smart Fitness Centers

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    The application of embedded systems in fitness centers is limited. Therefore, this paper proposes a system that can be integrated into weight machines to incorporate the benefits of the Internet of Things by collecting exercise routine data. A prototype consisting of a FRDM-K64 development board, NFC and distance sensors is proposed. Data of exercise routines such as repetition distance and time intervals were successfully measured by the prototype. Future applications include expanding this concept to cardiovascular or resistance equipment.ITESO, A. C

    Identification Of Potential Entomopathogenic Fungi Of Tetranychus Kanzawai Kishida (Tetranychidae: Acarina) Using Its-5.8s Rdna Region AS Molecular Marker

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    Fungi has been tested as one of the potential control agents for insect pests, which raises hopes for developing fungi as good biopesticides. The high variation within fungi species made taxonomic identification procedures more complex, thus molecular identification techniques are needed in addition to traditional morphological characteristics currently used as primary methods to classify fungi species. The objective of this research was to identify the species of the most pathogenic fungi to Tetranychus kanzawai Kishida using RAPD-PCR. The internal transcribed spacer of 5.8s rDNA (ITS-5.8s rDNA) sequence of these fungal isolates were amplified using two sets of universal primers for ITS and then analyzed. Molecular identification showed that these isolates had a higher of similarity to Metarhizium anisopliae than Metarhizium flavoviride

    Infection Process Of Entomopathogenic Fungi Metarhizium Anisopliae In The Tetranychus Kanzawai (Kishida) (Tetranychidae: Acarina)

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    The importance of fungal attack to acarina has been observed but not yet on Tetranychus kanzawai. When infected mite, either within in a same species or even in a different species of entomopathigenic probably have similar signs and simptoms to mites. Characteristic of entomopathogenic fungus to Tetranychus kanza-wai was investigated. Three selected isolates of Metarhizium anisopliae, from Philippines and Indonesia were evaluated. The following aspects were investigated: (1) Bioassay tes of virulence, (2) Koch Postulate and (3) Infection process on each fungus against mite. Virulence of Metarhizium anisopliae was 1.4 X 103, 7.2 X 102 , 5 X 102 PIB per ml on Ma4, Ma5 and Ma6, respectively. On Koch Postulates, Reinoculation and reisolation of all seven isolates from infected T. kanzawai showed definite signs of infection. This demonstrated its entomopathogenic capacity. In this experiment, adult mites were sprayed with 108 per ml concentrations of conidia observed under light microscope and Scanning Electron Microscopy (SEM). The result found T. kanzawai was very susceptible to three isolates M. anisopliae. In the end of the trials, fungal growth was detectable as early as 2 until 4 days of observation. Infection process with microphoto-graph and Scanning Electro Microscopy showed attachment, germination and penetration, extrusion and conidiogenesis fungal form

    As redes pessoais significativas como instrumento de intervenção psicológica no contexto comunitário

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    This article proposes a model for interventions in the networks of meaningful social relationships around a patient and describes its impact on the participants and on the psychological intervention process. The intention was to provide conditions so that all participants could be co-constructors of change possibilities in relationship to the perception of the problem that provoked the search for treatment. The clinical-qualitative method of "Grounded Theory" was used. The cases analyzed indicated the efficacy of the intervention with the families with psychiatric patients, in providing the network participants the possibility of finding their own potential for helping, for the psychotherapist in the responsibility distribution of the identified person care. The proposal of working with networks of meaningful social relationships does not exclude interventions from other theories. Rather, it increases the possibilities, both for the professionals understanding and for clinical psychology interventions in varied contexts.Este artigo visa apresentar proposta de sistematização do trabalho com redes significativas pessoais em torno de um paciente, e sua ressonância nas pessoas participantes do processo de intervenção psicológica. Buscou-se gerar condições para que os envolvidos na situação de intervenção pudessem ser co-construtores das mudanças, frente à visão do problema da pessoa que procurou atendimento. O método foi o clínico-qualitativo proposto pela "Grounded Theory". A análise dos casos estudados mostrou a eficácia da intervenção de rede no atendimento a famílias com pacientes psiquiátricos, para os participantes possibilitando entrar em contato com seu potencial de ajuda, para o psicoterapeuta distribuindo a responsabilidade no cuidado da pessoa identificada. O trabalho com a rede pessoal significativa não implica em desistência de outras ações de intervenção ou olhares teóricos, constituindo-se em aporte qualitativo, tanto para o profissional, como para o potencial de ação clínica da psicologia, em variados contextos de atuação

    Marine sponges of the genus neopetrosia with anti-inflammatory activity

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    The present study aimed to investigate the anti-inflammatory effect of marine sponges of the genus Neopetrosia which are abundant in the Colombian Caribbean. We obtained three fractions from a total methanolic extract of Neopetrosia rosariensis and proxima. In vivo activity was measured using λ-carrageenan-induced paw edema assay. The in vitro inhibitory effects were evaluated on myeloperoxidase activity (MPO) and nitric oxide (NO), prostaglandin E2 (PGE2), and tumor necrosis factor alpha (TNF- α) production. Total extracts of N. rosariensis and N. proxima (100 mg/Kg) significantly inhibited the paw edema of rats (71.74% and 60.06%, respectively). Dichloromethane and methanol fractions of Neopetrosia sponges reduced MPO activity. Only, dichloromethane fraction of N. rosariensis significantly inhibited NO (66%), PGE2 (30.5%) and TNF-α production (72%). Our results show anti-inflammatory activity in extracts and fractions from species of marine sponges belonging to Neopetrosia genus and open the way for complementary studies to purify and identify active molecules.Colegio de Farmacéuticos de la Provincia de Buenos Aire
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