280 research outputs found

    Conformal Antenna Array for Millimeter-Wave Communications: Performance Evaluation

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    In this paper, we study the influence of the radius of a cylindrical supporting structure on radiation properties of a conformal millimeter-wave antenna array. Bent antenna array structures on cylindrical surfaces may have important applications in future mobile devices. Small radii may be needed if the antenna is printed on the edges of mobile devices and in items which human beings are wearing, such as wrist watches, bracelets and rings. The antenna under study consists of four linear series-fed arrays of four patch elements and is operating at 58.8 GHz with linear polarization. The antenna array is fabricated on polytetrafluoroethylene substrate with thickness of 0.127 mm due to its good plasticity properties and low losses. Results for both planar and conformal antenna arrays show rather good agreement between simulation and measurements. The results show that conformal antenna structures allow achieving large angular coverage and may allow beam-steering implementations if switches are used to select between different arrays around a cylindrical supporting structure.Comment: Keywords: conformal antenna, millimeter-wave communications, patch antenna array. 11 pages, 10 figures, 1 tabl

    Caracterização morfológica e agressividade de populações de Pratylenchus spp. do RS em cana-de-açúcar e manejo de fitonematoides na cultura pelo emprego de rizobactérias.

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    (Mestrado) - do Programa de Pós-Graduação em Agronomia - Agricultura e Ambiente, Universidade Federal de Santa Maria (UFSM - FW, RS), Orientadora: Stela Maris Kulczynski, Coorientador: Cesar Bauer Gomes, Juliane Ludwig

    In vitro screening of interspecific hybrids (Malus spp.) for resistance to apple proliferation

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    A breeding programme was set up six years ago in Trentino as part of the Project “Scopazzi del Melo - Apple Proliferation” (SMAP) in order to obtain AP resistant apple rootstocks.Twenty-six hybrids generated from the crossings (Malus sieboldii, second generation, x Malus domestica) were micropropagated and studied in standardised conditions. An in vitro screening system for AP resistance previously set for the parents of the crosses was adopted and modified. Specific symptoms of the disease, as well as height and basal proliferation of the shoot and size of the leaves, were recorded in vitro at 3 months post-inoculation. At the same time, phytoplasma concentration was determined in the whole shoot by quantitative RT-PCR. An in vitro disease index taking into account all the above-mentioned parameters was developed.Each healthy genotype was graft-inoculated in triplicate with two different phytoplasma strains after plant rooting and acclimatisation. Phenotype and phytoplasma titre were evaluated in the roots the year after infection.Preliminary results indicated that the resistance trait segregates in the progenies. The resistant genotypes had lower phytoplasma concentrations than the susceptible controls, did not show AP-specific symptoms and their growth was not affected by infection. By comparing the resistant behaviour of the same genotypes, the in vitro screening allows for a quick selection of genotypes that are worth evaluating in the field for agronomic traits.Keywords: Apple Proliferation, Malus sieboldii, resistance screening, quantitative real-time PCR, disease inde

    Holographic quark matter with colour superconductivity and a stiff equation of state for compact stars

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    We present a holographic model of QCD with a first order chiral restoration phase transition with chemical potential, mu. The first order behaviour follows from allowing a discontinuity in the dual description as the quarks are integrated out below their constituent mass. The model predicts a deconfined yet massive quark phase at intermediate densities (350 MeV< mu <500 MeV), above the nuclear density phase, which has a very stiff equation of state and a speed of sound close to one. We also include a holographic description of a colour superconducting condensate in the chirally restored vacuum and study the resulting equation of state. They provides a well behaved first order transition from the deconfined massive quark phase at very high density (mu>500 MeV). We solve the Tolman-Oppenheimer-Volkoff equations with the resulting equations of state and find stable hybrid stars with quark cores. We compute the tidal deformability for these hybrid stars and show they are consistent with LIGO/Virgo data on a neutron star collision. Our holographic model shows that quark matter could be present at the core of such compact stars.Comment: 17 pages, 14 figure

    Desenvolvimento e reprodução da mariposa-oriental em macieira e pessegueiro.

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    O objetivo deste trabalho foi avaliar o desenvolvimento de estágios imaturos e parâmetros reprodutivos de adultos de Grapholita molesta em dietas naturais, constituídas de ramos e frutos de pessegueiro 'Vanguarda', frutos de macieira 'Gala' e 'Fuji', e em dieta artificial à base de milho. O delineamento experimental foi inteiramente casualizado. Considerou-se cada inseto uma repetição e, no estudo dos parâmetros biológicos dos adultos, cada casal foi considerado uma repetição. Foi calculada a tabela de vida de fertilidade. O tempo para o desenvolvimento das lagartas foi menor em ramos e frutos do pessegueiro, em comparação a frutos de macieira e dieta à base de farinha de milho. Quanto à sobrevivência das larvas, não houve diferença entre as dietas. Com base na tabela de vida de fertilidade, os frutos da cultivar Fuji foram mais adequados ao desenvolvimento de G. molesta do que os da Gala. Os ramos de pessegueiro foram mais adequados ao desenvolvimento do inseto do que os frutos. A dieta à base de farinha de milho foi adequada para a criação dos insetos em laboratório. As dietas avaliadas afetam a taxa de sobrevivência, o desenvolvimento e o potencial de crescimento populacional de G. molesta

    Three-dimensional printed ABS plastic peanut-lens with integrated ball grid array module for high-data-rate communications in F-band

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    A ball grid array (BGA) module integrated within a three-dimensional printed peanut-shaped lens is proposed for high-data-rate wireless communications in the F-band (116–140 GHz) between a video camera and a TV or a laptop. The module implements a 1?×?2 array antenna which radiates a wide beam in the horizontal plane (H-plane) and a narrower beam in the vertical plane (E-plane). The dielectric lens, fabricated in ABS-M30 plastic, is a shaped lens designed to achieve a fan-beam radiation pattern further narrowing the vertical plane and widening the horizontal plane of the BGA module. The realised gain of the full antenna system is required to exceed 5?dBi within a 120° angular interval in the horizontal plane and a 20° angular interval in the vertical plane. Measurements show a reflection coefficient below ?9?dB from 116 to 140?GHz and a maximum realised gain of 8.5?dBi at 130?GHz demonstrating feasibility of the cost-effective proposed design for a high-data-rate communications.info:eu-repo/semantics/acceptedVersio
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