82 research outputs found
CÁLCULO DE UN ÍNDICE DE HUMEDAD RELATIVA DEL AIRE, CONSIDERANDO LA RESILIENCIA TÉRMICA HORARIA DE LA TEMPERATURA
Un índice de humedad relativa (IHR-LST), que se calcula utilizando la diferencia entre la LST (temperatura de la
superficie del terreno), una hora después del amanecer y una hora después del medio día solar, dividida por el número
de horas entre estos dos periodos, se compara con la humedad relativa del aire de un conjunto seleccionado de
estaciones meteorológicas Los resultados muestran una clara asociación entre ambos valores, el índice de humedad
relativa y la humedad relativa del aire, lo que permite, con una única variable (LST distribuida por EUMETSAT /
LSASAF), obtener un comportamiento térmico de la superficie del suelo, así como, una estimación de la humedad
relativa de su dinámica temporal
Cálculo de um índice de humidade relativa do ar, considerando a resiliência térmica horária da temperatura lST, obtida por imagens de satellite
A relative humidity index (IHR-LST), estimated using the difference between the temperature LST (Land Surface Temperature), one hour after sunrise and one hour after solar noon, divided by the number of hours mediate these two periods, is compared with the air relative humidity of a selected set of meteorological stations.The results show a clear association between both values, relative humidity index and air relative humidity, enabling, with a single variable (LST distributed by EUMETSAT/LSASAF), to obtain a thermal behavior of the soil surface, as well as, an estimation of relative humidity from its temporal dynamics
Influence of ECAPressing temperature on crystallinity and mechanical behaviour of polypropylene and high-density polyethylene / Influência da temperatura de ECAPressing na cristalinidade e comportamento mecânico do polipropileno e do polietileno de alta densidade
In this paper, the influence of single equal channel angular pressing, ECAPressing, pass and processing temperature on crystallinity evolution and mechanical behaviour of the polymers polypropylene, PP, and high-density polyethylene, HDPE was investigated. ECAPressing tests were performed at the temperatures of 25, 50, 75 and 100°C for HPDE and 25, 90 and 120ºC for PP. The materials mechanical behaviour before and after ECAPressing tests was evaluated from room temperature compression tests while their crystallinity changings were analyzed through differential scanning calorimetry, DSC, experiments. In terms of strengthening and by comparison with as-received materials, it was observed an interesting efficiency of ECAPressing performed at 100°C for HDPE and 120°C for PP. In relation to crystallinity evolution, the results obtained from DSC tests showed its considerable increasing for higher pressing temperatures also by comparing either to as-received conditions or after single pass of equal channel angular pressing at room temperature
Multiconfiguration Dirac–Fock calculations of Zn K-shell radiative and nonradiative transitions
Acoes Integradas Luso-Francesas, Acao Ref. TC08-17;
Programa Pessoa 2017-2018;
EMPIR, Grant/Award Number: 17FUN02 MetroMMC;
FCT (Portugal), Grant/Award: SFRH/BPD/94234/2013;
FCT, Grant/Award Number: PTDC/FIS-AQM/31969/2017.Zinc K-shell radiative and radiationless transition rates are calculated using the multiconfiguration Dirac–Fock method. Correlation up to the 4p orbital is included in almost all transition rate calculations. Calculated radiative transition rates and transition probabilities are compared with Scofield's Dirac–Hartree–Slater and Dirac–Hartree–Fock calculations, presenting good agreement with the later. Radiative transition intensity ratios involving the strongest lines are compared with theoretical, experimental, and empirical-fit values. Most ratios are in close agreement with the empirical-fit values from NIST's Fundamental Parameters database. Calculated radiationless transition rates and ratios are compared with Chen et al.'s Dirac–Fock values and Safronova et al.'s Dirac–Fock values. The K-LL transition rates are overall lower than Chen et al.'s values, whereas the K-LX and K-XY transition rates are overall higher. Calculated K-LX/K-LL and K-XY/K-LL ratios are relatively close to the experimental values compared. Some calculated intensities relative to K-L2(1D2) are in good agreement with the experimental values, whereas others present worse agreement. The calculated fluorescence yield is higher than all theoretical, experimental, and empirical-fitted values compared, probably because the total radiationless transition rate value calculated in the present work is relatively low.publishersversionpublishe
Agriculture pest and disease risk maps considering MSG satellite data and Land Surface Temperature.
Pest risk maps for agricultural use are usually constructed from data obtained from in-situ meteorological weather stations, which are relatively sparsely distributed and are often quite expensive to install and difficult to maintain. This leads to the creation of maps with relatively low spatial resolution, which are very much dependent on interpolation methodologies. Considering that agricultural applications typically require a more detailed scale analysis than has traditionally been available, remote sensing technology can offer better monitoring at increasing spatial and temporal resolutions, thereby improving pest management results and reducing costs. This article uses ground temperature, or land surface temperature (LST), data distributed by EUMETSAT/LSASAF (with a spatial resolution of 3 x 3 km (nadir resolution) and a revisiting time of 15 min) to generate one of the most commonly used parameters in pest modelling and monitoring: “thermal integral over air temperature (accumulated degree-days)”. The results show a clear association between the accumulated LST values over a threshold and the accumulated values computed from meteorological stations over the same threshold (specific to a particular tomato pest). The results are very promising and enable the production of risk maps for agricultural pests with a degree of spatial and temporal detail that is difficult to achieve using in-situ meteorological stations
Overview and calculation of X-ray K-shell transition yields for comprehensive data libraries
PTDC/FIS-AQM/31969/2017
Programa Pessoa 2017-2018,
Proc. N 441.00 France
SFRH/BPD/94234/2013
Grant/Award Number: 17FUN02 MetroMMCThe simulation of atomic relaxation relies on data libraries with tabulated partial fluorescence yield values of radiative transitions, commonly derived from the Evaluated Atomic Data Library (EADL). However, recent studies support that the data library EADL could be improved by adopting Scofield's Hartree-Fock calculations instead of current Scofield's Hartree-Slater calculations. This work presents a bibliography overview of relevant atomic parameter values in order to verify the partial fluorescence yields presented in EADL. The references include libraries and articles, in which the atomic parameter values were theoretically calculated, experimentally measured, or obtained with semi-empirical and empirical fitting formulas. We present a comparison of total K-shell fluorescence yields and partial K-L2, K-L3, K-M2, K-M3 fluorescence yields that are either obtained directly from its references, or are derived from atomic parameters presented in these references. Additionally, we obtain comprehensive partial fluorescence yield values from the combination of semi-empirical and empirical fitting functions from different references. The comparisons performed in this work confirm that total K-shell, partial K-L2, and partial K-L3 fluorescence yield values, obtained from Scofield's Dirac-Slater calculations have better agreement with the most recent empirical values. Partial K-M2, and partial K-M3 fluorescence yield values obtained from Scofield's Dirac-Fock calculation have better agreement with the most recent empirical values. Therefore, further studies should be performed before changing the EADL data library.publishersversionpublishe
Application of Unsupervised Multivariate Analysis Methods to Raman Spectroscopic Assessment of Human Dental Enamel
Funding Information: Acknowledgments: This work has been financially supported by Fundação para a Ciência e a Tecnolo-gia through the LIBPhys funding UID/FIS/ 04559/2021 and I. Otel PhD grant PD/BDE/143107/2018. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.This work explores the suitability of data treatment methodologies for Raman spectra of teeth using multivariate analysis methods. Raman spectra were measured in our laboratory and obtained from control enamel samples and samples with a protective treatment before and after an erosive attack. Three different approaches for data treatment were undertaken in order to evaluate the aptitude of distinguishing between groups: A—Principal Component Analysis of the numerical parameters derived from deconvoluted spectra; B—PCA of average Raman spectra after baseline correction; and C—PCA of average raw Raman spectra. Additionally, Hierarchical Cluster Analysis were applied to Raman spectra of enamel measured with different laser wavelengths (638 nm or 785 nm) to evaluate the most suitable choice of illumination. According to the different approaches, PC1 scores obtained between control and treatment group were A—50.5%, B—97.1% and C—83.0% before the erosive attack and A—55.2%, B—93.2% and C—87.8% after an erosive attack. The obtained results showed that performing PCA analysis of raw or baseline corrected Raman spectra of enamel was not as efficient in the evaluation of samples with different treatments. Moreover, acquiring Raman spectra with a 785 nm laser increases precision in the data treatment methodologies.publishersversionpublishe
Accuracy improvement in XRF analysis for the quantification of elements ranging from tenths to thousands μg g-1in human tissues using different matrix reference materials
UID/FIS/04559/2019 to LIBPhys-UNL from the FCT/MCTES/PIDDAC, Portugal. FCT contract No. PD/BD/128324/2017.In this work, we aim at achieving the most accurate quantitative determination of elements in human tissues by means of X-ray Fluorescence spectrometry using the external calibration approach. A calibration curve built using a set of certified reference materials (CRM) of animal tissue was compared with the one obtained with a set of CRMs of plants and leaves with lower atomic number Z but with correction of the matrix using the scattering peaks of the X-ray tube anode. Finally, a calibration curve combining the two sets of CRMs was built and the accuracy of the quantification using the three methods was compared and a more precise method of quantification was obtained. This improved approach was tested on five paired samples of normal and tumour human tissue. Despite the high heterogeneity of the samples, and given the improvement in accuracy of the measurements, significant differences were found in the elemental concentration of low-Z elements. This journal isauthorsversionpublishe
Estudo preliminar sobre o comportamento de 21 cultivares de feijão-mungo em Itaguaí, RJ
Twenty-one cultivars of mung bean, Vigna radiata (L.) Wilczek, originated from Taiwan, were studied at the experimental station - UAPNP Biologia do Solo/EMBRAPA, Seropédica, ltaguaí, Rio de Janeiro State, Brazil, in a Red-yellow Podzolic Soil, ltaguaí serie, in the dry season. Cultivars grain yields were influenced directly by nodulation, total plant N and, principally, by seed number per pod. Cultivars V 3476 (Philippines), CV 2764A, VC 2755A, and VC 1000C (Taiwan) yielded more than 1,700 kg/ha and presented better agronomical characteristics than the other cultivars. The majority of the cultivars showed erect growth habit, good plant height, good nodulation, and uniform plant maturity. They showed possibility of two pod harvesting for grain production.No campo experimental da UAPNP Biologia do Solo/EMBRAPA Seropédica, Itaguaí, RJ, estudaram-se 21 cultivares de feijão-mungo, Vigna radiata (L.) Wilczek, oriundas de Taiwan, em solo Podzólico Vermelho-Amarelo da série ltaguaí, no plantio da época da seca. As produções de grãos das cultivares foram influenciadas diretamente pela nodulação, N total das plantas e, principalmente, pelo número de sementes por vagem. As cultivares V 3476 (Filipinas), VC 2764A, VC 2755A e VC 1000C (Taiwan) produziram acima de 1.700kg de grãos/ha e apresentaram características agronômicas desejáveis superiores às das demais cultivares. A maioria das cultivares apresentou porte ereto, boa altura das plantas, boa nodulação e maturação das vagens bastante uniforme, possibilitando apenas duas colheitas de vagens para produção de grãos
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