2,133 research outputs found

    Rainbow Perfect Domination in Lattice Graphs

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    Let 0<n\in\mathbb{Z}. In the unit distance graph of ZnRn\mathbb{Z}^n\subset\mathbb{R}^n, a perfect dominating set is understood as having induced components not necessarily trivial. A modification of that is proposed: a rainbow perfect dominating set, or RPDS, imitates a perfect-distance dominating set via a truncated metric; this has a distance involving at most once each coordinate direction taken as an edge color. Then, lattice-like RPDS s are built with their induced components C having: {i} vertex sets V(C) whose convex hulls are n-parallelotopes (resp., both (n-1)- and 0-cubes) and {ii} each V(C) contained in a corresponding rainbow sphere centered at C with radius n (resp., radii 1 and n-2)

    The influence of hot pressing on high density fibreboards, when the panels are used for overlaying

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    Um conjunto de painéis de fibras de alta densidade, colados com uma resina de melamina/ureia-formaldeído, foi submetido a operações de prensagem a quente, de modo a estudar a influência desta operação nas propriedades do substrato. Usou-se uma prensa de pratos, a uma pressão que permitisse um contacto firme entre os painéis e os pratos da prensa. Foi desenvolvido um plano experimental para três temperaturas diferentes de 95, 180 e 210 º C e dois tempos de prensagem, de 22 e 35 segundos, para cada uma delas. Os painéis foram fabricados com fibras de pinho (Pinus pinaster) a uma densidade média de 930 kg/m3 e espessura média de 6,7 mm De acordo com os resultados obtidos, as operações de pós-fabrico dos painéis de alta densidade resultaram numa ligeira melhoria do módulo de elasticidade, da tensão de rotura à flexão estática e da resistência interna dos painéis usados como substrato. Observou-se também uma ligeira diminuição da humidade de equilíbrio e espessura dos painéis, bem como um aumento da densidade e do inchamento, com o aumento da temperatura e tempo de prensagem.ct A series of high density fiberboard (HDF) panels, bonded with melamine/urea-formaldehyde (MUF), were exposed to a post manufacture hot pressing at various temperatures and pressing durations using a hot press and just enough pressure to ensure firm contact between the panel and the press platens. The experimental plan was developed for three different temperatures of 95, 180 and 210ºC and two different pressing times, of 22 and 35 seconds. The panels were made with pine fibers (pinus pinaster) at a target density of 930 kg/m3 and target thickness of 6.7 mm. The results indicated that the pos-manufacture hot-pressing of the exterior HDF panels resulted in a slightly improvement of the modulus of elasticity (MOE), bending strength and internal bonding (IB) of the panels used as substrates. A reduction in moisture content and thickness as well as an increase in density and thickness swelling was also noticed with an increase in the temperature and pressing timeinfo:eu-repo/semantics/publishedVersio

    Interleukin-6 expression by hypothalamic microglia in multiple inflammatory contexts: a systematic review

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    Interleukin-6 (IL-6) is a unique cytokine that can play both pro- and anti-inflammatory roles depending on the anatomical site and conditions under which it has been induced. Specific neurons of the hypothalamus provide important signals to control food intake and energy expenditure. In individuals with obesity, a microglia-dependent inflammatory response damages the neural circuits responsible for maintaining whole-body energy homeostasis, resulting in a positive energy balance. However, little is known about the role of IL-6 in the regulation of hypothalamic microglia. In this systematic review, we asked what types of conditions and stimuli could modulate microglial IL-6 expression in murine model. We searched the PubMed and Web of Science databases and analyzed 13 articles that evaluated diverse contexts and study models focused on IL-6 expression and microglia activation, including the effects of stress, hypoxia, infection, neonatal overfeeding and nicotine exposure, lipopolysaccharide stimulus, hormones, exercise protocols, and aging. The results presented in this review emphasized the role of injury-like stimuli, under which IL-6 acts as a proinflammatory cytokine, concomitant with marked microglial activation, which drive hypothalamic neuroinflammation. Emerging evidence indicates an important correlation of basal IL-6 levels and microglial function with the maintenance of hypothalamic homeostasis. Advances in our understanding of these different contexts will lead to the development of more specific pharmacological approaches for the management of acute and chronic conditions, like obesity and metabolic diseases, without disturbing the homeostatic functions of IL-6 and microglia in the hypothalamus.2019COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPSem informação2013/07607-

    Mitigating Electromagnetic Noise When Using Low-Cost Devices in Industry 4.0

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    [EN] Transitioning toward Industry 4.0 requires major investment in devices and mechanisms enabling interconnectivity between people, machines, and processes. In this article, we present a low-cost system based on the Raspberry Pi platform to measure the overall equipment effectiveness (OEE) in real time, and we propose two filtering mechanisms for electromagnetic interferences (EMIs) to measure OEE accurately. The first EMI filtering mechanism is the database filter (DBF), which has been designed to record sealing signals accurately. The DBF works on the database by filtering erroneous signals that have been inserted in it. The second mechanism is the smart coded filter (SCF), which is used to filter erroneous signals associated with machine availability measurements. We have validated our proposal in several production lines in a food industry. The results show that our system works properly, and that it considerably reduces implementation costs compared with proprietary systems offering similar functions. After implementing the proposed system in actual industrial settings, the results show a mean error (ME) of -0.43% and a root mean square error (RMSE) of 4.85 in the sealing signals, and an error of 0% in the availability signal, thus enabling an accurate estimate of OEE.This work was supported in part by the Government of Aragon and the European Social Fund "Construyendo Europa desde Aragon" under Grant T40_20D Research Group, and in part by the "Ministerio de Ciencia, Innovacion y Universidades, Programa Estatal de Investigacion, Desarrollo e Innovacion Orientada a los Retos de la Sociedad, Proyectos I+D+I 2018," Spain, under Grant RTI2018-096384-B-I00.Herrero, ÁC.; Sangüesa, JA.; Martínez, FJ.; Garrido, P.; Tavares De Araujo Cesariny Calafate, CM. (2021). Mitigating Electromagnetic Noise When Using Low-Cost Devices in Industry 4.0. IEEE Access. 9:63267-63282. https://doi.org/10.1109/ACCESS.2021.3074588S6326763282

    Efficient parallelization on GPU of an image smoothing method based on a variational model

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    Medical imaging is fundamental for improvements in diagnostic accuracy. However, noise frequently corrupts the images acquired, and this can lead to erroneous diagnoses. Fortunately, image preprocessing algorithms can enhance corrupted images, particularly in noise smoothing and removal. In the medical field, time is always a very critical factor, and so there is a need for implementations which are fast and, if possible, in real time. This study presents and discusses an implementation of a highly efficient algorithm for image noise smoothing based on general purpose computing on graphics processing units techniques. The use of these techniques facilitates the quick and efficient smoothing of images corrupted by noise, even when performed on large-dimensional data sets. This is particularly relevant since GPU cards are becoming more affordable, powerful and common in medical environments

    CONVERSOR AC-DC EM MODO CONTÍNUO DE CORRENTE COM COMPENSAÇÃO EM FREQUÊNCIA PARA LÂMPADAS LED DE BAIXO CUSTO E ALTA EFICIÊNCIA

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    Este artigo apresenta uma nova arquitetura de um driver de LEDs de alto brilho, com baixo custo e elevado rendimento. Emprega-se um conversor do tipo CUK em modo contínuo de corrente com compensação em frequência, para alimentação dos LEDs de alto brilho através da rede elétrica, a partir de 85V a 265V, operando em alta frequência com comutação por Modulação por Largura de Pulso (MLP) e conectado a um filtro ressonante LC série para alimentação da carga com proteção contra surto de tensão na entrada. Foram utilizados vinte LEDs de Alta Potência da OSRAM 720-GWPSL e um circuito com corrente constante em modo Off-line. A arquitetura proposta visa apresentar uma proposta de um driver de baixo custo e baixo consumo de corrente. É apresentado o estudo comparativo entre o protótipo deste dispositivo a partir dos gráficos obtidos com os resultados de medições em laboratório

    Relaxations in Ba2BiSbO6 Double Complex Perovskite Ceramics

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    The electric properties of the complex double perovskite Ba2BiSbO6 have been investigated using impedance spectroscopy in the frequency range from 1 Hz up to 1 MHz and in the temperature range from room temperature up to 560 K. There are two contributions to the electrical properties due to the grain and grain boundary. The oxygen vacancies play an important role in the conductivity and strongly increase the dielectric constant at high temperatures. The analysis of the frequency dependence of the conductivity clearly shows the structural phase transition of this compound near 515 K
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