2,570 research outputs found

    Um Sistema de Informação Geográfica para a prevenção e combate aos incêndios florestais (SIGPF)

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    Comunicação apresentada no Congresso Ibérico de Fogos Florestais que decorreu de 17 a 19 de Dezembro de 2000, em Castelo Branco, na Escola Superior Agrária do Instituto Politécnico.Para uma maior eficácia na prevenção e combate aos fogos florestais é fundamental um conhecimento adequado e actualizado da área de intervenção. No âmbito da protecção civil, compete às Câmaras Municipais, em conjugação com outras instituições, a elaboração de Planos Municipais de Intervenção Florestal, no sentido de minimizar o risco da ocorrência de incêndios e optimizar os meios envolvidos no combate. Os sistemas de informação geográfica ao relacionarem informação espacial e alfanumérica, possibilitando a manipulação, análise e visualização dos dados, apresentam-se como um recurso informático de extrema importância no planeamento de medidas de prevenção e combate aos fogos florestais. A metodologia utilizada passou por uma sequência de fases usuais na construção deste tipo de aplicações, tendo como objectivo a caracterização da área de estudo quanto à ocupação do solo, rede viária, superfícies com água e postos de vigia. Os resultados obtidos são (1) cartografia temática de ocupação de solo e infra-estrutura (2) carta de risco de incêndio florestal

    High temperature tribological characterization of TiAl laser cladding coating on Ti6Al4V alloy

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    Ti6Al4V alloy has proven to be an important engineering material due to the excellent strength, weight ratio, high corrosion resistance and biocompatibility. However, the alloy is susceptible to mechanical degradation in applications involving sliding wear or abrasion. In order to improve wear resistance, coatings by laser cladding of intermetallic Ti48Al2Cr2Nb on Ti6Al4V have been developed. Different process parameters: laser power (W), scanning speed (mm/min), powder feeding rate (g/min) and preheating temperature of substrate (°C) were optimized, resulting in a microstructure of the coatings considered appropriate, with good metallurgical bond, though cracks and pores were observed [1]. The composition and microstructure of the coatings were evaluated using optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis, further the tribological properties were evaluated using a ball on disk tribometer, with Al2O3 ball, constant speed of 0.1 m/s, 10 N load at room temperature and 500 °C. We measure the 3D surface topography obtained from the wear scar and calculated the wear rate. The coatings microstructure consists of -TiAl phase and 2-Ti3Al. The wear test results at room temperature show a lower wear rate for the coating compared to the substrate. At high temperature the coating have a higher friction coefficient and a higher rate of wear is obtained when compared with the substrate, obtaining differences between the coatings depending on the wear mechanism observed in the worn surface.The authors acknowledge the economical support from the Ministry of Science and Innovation of the Government of Spain through research project MAT2011-28492-03 and the Generalitat Valenciana through support ACOMP/2014/151. Thanks also to Dr. José Luis Jorda by X-ray diffraction analysis performed

    Development of laser cladding MCrAlY coatings: high temperature friction and wear behaviour

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    Temperature can have a significant effect on the extent of wear damage of metallic components. Thermal barrier coatings with MCrAlY (where M=Ni, Co, Fe or combinations) alloys can improve the high temperature tribological and friction wear behaviour. In this work the dry friction and wear behaviour at room temperature and high temperature of new developed NiCoCrAlY and CoNiCrAlY laser cladding coatings were evaluated. Dense coatings, with good metallurgical bonding to the AISI 304 substrate was obtained by coaxial laser cladding tracks (40% overlapping), with previously optimized laser parameters. Tribological tests were performed by sliding wear at room temperature and 500 ºC, with an Al2O3 counterpart in ball on disk configuration tribometer. The wear scar surface was evaluated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) microanalysis. The 3D wear track topography was measured by inductive contact profilometer which enabled the wear rate calculation. The microstructure of the coatings consists of - Ni/-NiAl or -Co/-(Co,Ni)Al phases depending on the chemical composition of the alloy, as confirmed by X-ray diffraction (XRD) analysis. The wear test results show a reduction in wear rate at high temperature for all materials tested. For the NiCoCrAlY coating, the high temperature also reduces the friction coefficient, while it significantly increases the friction coefficient of CoNiCrAlY coating. The main damage mode is abrasion and adhesion, caused by oxides and partially-oxidized particles in the contact surface. The coatings and substrate results were compared, resulting in improved wear behaviour.The authors acknowledge the financial support of the Ministry of Science and Innovation of the Government of Spain through research project MAT2011-28492- C03 and the Generalitat Valenciana through ACOMP/2013/114 support. Professor Juan Carlos Pereira Falcón thanks the University of Carabobo for the financial support to pursue his doctoral studies at the UPV

    Multi-monitorização de estufa agrícola

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    A agricultura tem recorrido, tradicionalmente, a métodos empíricos que não rentabilizavam a produção e estava fortemente dependente das condições meteorológicas. Para melhorar a produção agrícola, surgiram as estufas agrícolas que permitem culturas de elevado valor acrescentado. Estas permitem também a elaboração de estudos de conceitos de causa-efeito, que possibilitam a construção de modelos e sistemas para melhorar a produção e a qualidade de determinada colheita. Com base nesta realidade, este artigo apresenta e descreve um trabalho que se encontra em fase de desenvolvimento por investigadores de duas escolas do Instituto Politécnico de Castelo Branco (IPCB) e que visa o desenvolvimento de um sistema para monitorização de uma estufa agrícola situada na Escola Superior Agrária (ESA) daquele Instituto

    Greenhouse watching system using multi-technologies

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    Traditional agriculture uses empiric methods and is very exposed to meteorological conditions. To increase the agriculture production, greenhouses had appeared to allow crops with higher quality. Greenhouses also permit the study of cause-effect concepts that by them allow building models that improve the crop’s production and quality. Based on this reality, this paper presents a system developed by researchers of two schools of the Instituto Politécnico of Castelo Branco(IPCB) to monitor a greenhouse located in the campus of Escola Superior Agrária (ESA). This proposed system uses several different technologies

    Genotypic differences in cyanogenic glycosides levels of compatible Prunus persica P. Persica and incompatible P. persica P. mume combinations

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    Graft incompatibility is a phenomenon associated with complex physiological, biochemical, and genetic interactions between scion and rootstock. The main objective of this work was to assess the role of cyanogenic glycosides (CGs), amygdalin and prunasin, in the graft incompatibility of Prunus and possible biochemical effects in compounds of the phenylpropanoid pathway. Graft compatibility, amygdalin and prunasin content, phenylalanine ammonia-lyase activity, total phenolic compounds content and antioxidant activity, were studied in different graft combinations (Chimarrita/Capdeboscq; Chimarrita/Tsukuba 1; Chimarrita/Umezeiro; Maciel/Capdeboscq; Maciel/’Tsukuba 1; Maciel/Umezeiro) and ungrafted genotypes. The results indicate that there was graft incompatibility of Chimarrita and Maciel cultivars grafted into Umezeiro rootstock. Combinations identified as incompatible showed higher prunasin concentration and phenylalanine ammonia-lyase (PAL) activity in rootstock and greater concentration of total phenolics compounds and antioxidant activity in scion and rootstock. The results indicate that large differences in CGs concentration, especially prunasin, can be the graft incompatibility cause between Prunus persica and P. mume. The prunasin concentration may be considered a promising marker to predict graft compatibility between P. persica and P. mume

    Development of ternary diagrams for estimating water retention properties using geostatistical approaches

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    Most pedotransfer functions (PTFs) have adopted soil texture information as the main predictor to estimate soil hydraulic properties, whether inputs are defined in terms of the relative proportion of different grain size particles or texture-based classifications. The objective of this studywas to develop ternary diagrams for estimating soil water retention (θ) at−33 and−1500 kPa matric potentials, corresponding to the field capacity and wilting point, respectively, from particle size distribution using two geostatistical approaches. The texture triangle was divided into a 1% grid of soil texture composition resulting in 4332 different soil textures. Measured soil water retention values determined in 742 soil horizons/layers located in Portugal were then used to develop and validate the hydraulic ternary diagrams. The development subset included two-thirds of the data, and the validation subset the remaining samples. The measured soil water content values were displayed in the ternary diagram according to the coordinates given by the particles size distribution determined in the same soil samples. The volumetric water content values were then predicted for the entire ternary diagram using two different geostatistical interpolation algorithms (ordinary kriging and the empirical best linear unbiased predictor). Uncertainty analysis resulted in a root mean square error below 0.040 and 0.034 cm3 cm−3 when comparing the interpolated water contents at −33 and −1500 kPa matric potential values, respectively, with the measured ones included in the validation dataset. The estimation variance calculated with both methods was also considered to access the uncertainty of the predictions. The available water content of Portuguese soils was then derived from θ−33 kPa and θ−1500 kPa ternary diagrams developed with both approaches. The hydraulic ternary diagrams may thus serve as simplified tools for estimating water retention properties from particle size distribution and eventually serve as an alternative to the traditional statistical regression and data mining techniques used to derive PTFsinfo:eu-repo/semantics/publishedVersio

    Factores Biomecânicos no Desenvolvimento de Patologias nos Membros Pélvicos em Avicultura Industrial

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    O crescente aparecimento de patologias nos membros pélvicos nos efectivos de frangos de carne e de perus, especialmente nas estirpes de crescimento rápido e de peso adulto elevado, que se traduzem em perdas económicas significativas, faz do estudo da biologia do osso, em particular das questões relacionadas com aspectos biomecânicos, uma área de primordial importância na indústria avícola. Pretende-se com a presente revisão evidenciar a associação que existe, em avicultura industrial, muito particularmente no sector da produção de carne, entre factores biomecânicos e o desenvolvimento de algumas patologias nos membros pélvicos
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