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Dicionário de expressões idiomáticas
Sociologia do desporto
Contém referências bibliográficas
Contém: Vol. I: Fundamentos. - XI, 396 p.
Relatório do Trabalho de Fim de Curso de Engenharia Florestal.
Dissertaçäo original expressamente elaborada para obtençäo do grau de Doutor em Engenharia Zootécnica
Contém referências bibliográficas
Relatório do Trabalho de Fim de Curso de Engenharia de Produção Agrícola.
Introduction: A. melanoxylon wood has a large commercial application given its anatomical characteristics and mechanical properties. However studies on the anatomical characterisation of this species grown in Portugal are scarce.
Objectives: To describe the transverse anatomical characteristics and their within-tree variation of A. melanoxylon trees growing in Portugal.
Methods: 20 trees were analysed in transverse section for tree radial position (10%; 50%; 90%) and five height levels (base, 15%; 35%; 65%; 80%) in north and south directions. Measurements included: fibre diameter (m), fibre wall thickness (m), Runkle index; Flexibility index, vessel number (vessel number /mm2), porosity (%) and vessel width (m).
Results: Earlywood fibres have lower wall thickness and higher lumen diameter than latewood fibres. Runkle and flexibility indexes confirm its potential for pulp and paper production. Porosity was lower near the pith as a result of a slight increase of vessel number with smaller size.
Conclusions: Blackwood showed potential as an alternative species to supply the industry.
This paper reports on the relationship between the fibre morphology of six Acacia melanoxylon bleached kraft pulps, produced from wood chips with basic densities of 449, 489, 493, 505, 514 and 616 kg/m3, and their papermaking potential. Six wood samples were selected in order to provide pulps with markedly different fibre morphological properties. The pulps were beaten in a PFI mill at 500, 2500 and 4500 revolutions under a refining intensity of 1.7 N/mm and their papermaking potential evaluated. The mean values of fibre length, fibre width and coarseness ranged between 0.78 and 0.99 mm, 17.8 and 19.4 cm, and 4.8 and 6.2 mg/100 m, respectively. As expected, the fibres characteristics have very high impact on handsheet structure, including smoothness, and on mechanical and optical properties, for the unbeaten pulps. At a given beating input (same PFI revolutions), the differences between pulps remain very high. Moreover, for a given paper density, tensile and tear strength, and light scattering coefficient are very sensitive to mean pulp fibre characteristics.
info:eu-repo/semantics/publishedVersion
info:eu-repo/semantics/publishedVersion
Uranium and thorium are toxic in different environments. The exploitation of uranium
mines and associated mine drainage leaching towards streams, sediments, and soils cause relevant
pollution. The U-mine areas present high concentrations of potentially toxic elements with several
consequences to ecosystems and human health. Physicochemical and potentially toxic elements of
mine dumps, stream sediments, and soils from the Canto Lagar uranium mine area (Central Portugal)
were analyzed. Stream sediments, soils, and mine dumps show a large range in the concentration
values of Fe, U, As, Cu, Zn, Pb, and Th, suggesting geological and mine contributions. Most of the
selected potential toxic elements from sediments present a low to moderate contamination degree,
except for As, W, and U, which vary between high and very high contamination index. The soils must
not be used in agricultural or residential activities due to contamination in As and U. This abandoned
mine represents an environmental risk due to the spatial mobility and dispersion of potentially toxic
elements from the dumps to the sediments and soils, as well as by surface runoff and wind.
The Picoto mining area is in the village of Vilar Seco (Viseu), central Portugal. Mineralization
occurs mainly in quartz veins with meta-torbernite and uranophane and some U-bearing
minerals, cutting a Variscan granite. Exploitation took place in two phases, between 1917 and 1953,
and since the closure, the area has never been remediated. Water–rock interaction processes, including
the mobility of potentially toxic elements through soil and water (surface and groundwater),
were identified with the determination in situ of physicochemical parameters and selected anions
and cations, by ICP-OES. The soils are contaminated with As (>44 mg/kg), Cu (>23 mg/kg), and U
(>40 mg/kg) and cannot be used for agricultural or domestic purposes. The waters are generally
weakly mineralized and have pH values ranging from acidic to neutral. However, some of them
are contaminated with NO2 (up to 2.3 mg/L), Fe (up to 1849 mg/L), Mn (up to 777 mg/L), Cu
(up to 5.4 g/L), As (up to 14.7 g/L), and U (up to 66.2 g/L) and cannot be used for human
consumption or agricultural activities. The soil and water contamination are mainly related to the
old mine activities and the subsequent human activities that have developed in the area.
Monofloral Lavandula spp. honey is very appreciated by consumers due to its characteristic and pleas antaroma and flavor. Given the economic importance of this ype of honey, it is important to develop a rapid and nonexpensive methodology that allows certifying its quality. In this context, this study aimed to compare the applicability and accuracy of FTIR-ATR and FT-Raman techniques for the quality evaluation of Lavandula spp. honey.
Calibration models, with PLS regression models, were
obtained for both methodologies concerning the following
parameters: total acidity, reducing sugars, hidroximetilfurfural (HMF), electrical conductivity, ash, proline content, diastase activity, apparent sucrose, total flavonoids,
and total phenolic contents. The calibration models had
high regression coefficients, r
2 (FTIR-ATR: 0.965–0.996;
FT-Raman: 0.983–0.999), high ratios of performance to
deviation, RPD (FTIR-ATR: 5.4–15.7; FT-Raman: 7.6–53.7),
and low root mean square errors (RMSEs; FTIR-ATR:
0.005–3.0; FT-Raman: 0.004–1.02). These results corroborate the potentiality of FTIR-ATR and FT-Raman for quality
evaluation and evaluation of the chemical properties of
Lavandula spp. honey even though FT-Raman technique
provided more accurate models.
