Resumo em Inglês:

ABSTRACT The objective of this study was to evaluate the polyester-based fiber composites reinfor ced with filaments/fibers of mauve treated with NaOH and maleic anhydride. The che mical treatment of the mauve filament/fibers (3 cm of length) was carried out, first with NaOH, followed by maleic anhydride. The resin used was ortho unsaturated polyester with addition of catalyst peroxide methyl ethyl ketone. The composites were prepared with 15% filaments (w/w) and tested for water absorption, three-point bending, tensile and impact strength. Fiberglass composites were produced using the same methodology for comparison purpose. The results demonstrate the potential use of mauve filaments. For some properties, the mauve composites showed better mechanical properties than fiberglass composites (three-point bending and tensile). The treatment of the filaments had varied effect and did not improve the mechanical properties. However, for the water absorption was observed a reduction of 35% in composites with treated mauve filaments.

Resumo em Inglês:

ABSTRACT The use of height-diameter models have important applications in the management of eucalyptus plantations. The aim of this paper is to provide adequate height models based on the diameter and stand variables that could be easily used and applied to plantation’s management. The data was based on tests located in Espírito Santo and Bahia. A total of 312 plots, including 35 different treatments (different initial planting densities, number and severity of thinning operations, fertilization regimes, among others), and four different clones. This resulted in 2,407 conditions for 85,608 tree measurements. The constructed equations were based on mixed-effect models, in order to accommodate possible autocorrelations, to address variations between sites and to obtain locally calibrated estimates. Among the different model structures and combination of variables tested and presented, the best model showed a coefficient of determination of 0.953 and 0.988, for the fixed and fixed+random parts, respectively. The model included a random factor for measurements-within-tree and tree-within-plot. The bias of the fixed part was 0.208 cm (0.0659%). We believe the models in this study can have broad applications in management and inventory methods applied to plantations.

Resumo em Inglês:

ABSTRACT This study aimed to evaluate the dynamics of the physical and chemical recovery of the substrates of waste dumps of different ages undergoing natural regeneration, in a calcary mining in Salto de Pirapora - SP, Brazil. Characterization of the vegetation, vegetation and physical and chemical cover of the substrates of the abandoned waste dumps since 1994 and 2013 and the soil of a native forest fragment adjacent to the mining was carried out. Twelve plots of 10x10m were allocated in each environment. It was verified that the soil cover rate with herbaceous, grassy, regenerating and litter of the sterile stacks are similar to the native forest fragment. The same was observed for the physical characterization of soil resistance to penetration, soil moisture content and relative light index. For the chemical characteristics, in all areas sampled there is aluminum deficiency which, consequently, presented low potential acidity and alkaline pH. The CEC of the substrates of the waste dumps presented values similar to the CEC of the native forest fragment, with abundance in some essential nutrients, indicating the possibility of vegetation development in the sterile stacks and the contribution of the natural regeneration to the substrates. Thus, the plant-soil relationship via natural regeneration in the sterile piles contributed to the improvement of the edaphic quality of the substrates over time, being a potential form of recovery in calcary mining. Thereby, the Fabaceae predominated on the waste dumps, especially Leucaena leucocephala, which, despite being an exotic species, is relevant for the current recovery stage of the substrates.

Resumo em Inglês:

ABSTRACT The productive sustainability of eucalyptus planting is threatened when both diseases and disorders of growth occur. These interferences can have abiotic origin as environmental conditions can negatively affect the wood quality. This study has the goal of evaluating influence of different levels of physiological disorders in dendrometric variables and wood quality from seven-year-old Eucalyptus grandis x Eucalyptus urophylla hybrids intended for wood pulping production. The trees from commercial plantations in State of Maranhão, Brazil were separated into three levels of physiological disorders by means of morphologic changes. Then, they were evaluated according to dendrometric variables, anatomical characteristics, chemical properties, density of wood, and kraft pulp process. The physiological disorder levels significantly influenced all evaluated properties. Moreover, the wood from trees with higher severity of symptoms resulted in higher average values of dendrometric variables, basic density, and fibers dimensions. In addition, apparent density exhibited a different standard in the pith region with increase on radial wood profile. Trees with the least severe disorders exhibited changes in dendrometric and anatomical variables, mainly in wood volume and fibers dimensions, respectively.

Resumo em Inglês:

ABSTRACT In this study, the hydration behavior of gypsum paste mixed with bagasse and kenaf fibers as lignocellulosic material and fiberglass as inorganic material is evaluated. Moreover, the properties of gypsum-bonded fiberboard (GBFB) are examined using bagasse fibers (Saccharum officinarum.L), kenaf fibers (Hibiscus cannabinus.L) and industrial fiberglass. The weight ratios of fiberglass (at three levels 0, 3 and 6%), bagasse fiber (at three levels 0, 7.5 and 15%) and kenaf fiber (at three levels 0, 7.5 and 15%) to gypsum are used to make the gypsum-bonded fiberboard with the nominal density 1.10 g.cm-3 . After preparing the fiberboard, its flexural properties were examined. Response surface methodology (RSM) and artificial neural network (ANN) were used to model the bending strength of gypsum-bonded fiberboard. According to the hydration tests, it was determined that as the extractives in the lignocellulosic materials increased, the temperature of the mixture decreased and its setting time increased. According to the bending test results, it was determined that there is an ideal consistency between the predicted values and the observed data, so that as bagasse and kenaf fiber increased, the modulus of rupture (MOR) increased. Maximum MOR of panel was predicted to be 10.81 MPa and 11MPa by RSM and ANN at optimum condition. Based on the statistical analysis, the training and validation data sets of the studied models were compared by the coefficient of determination (R2), root mean squares error (RMSE) and mean absolute error (MAE). ANN model showed a much more accurate prediction than RSM in terms of the values R2, RMSE and MAE.

Resumo em Inglês:

ABSTRACT In Brazil there are six well-defined biomes and the Caatinga represents 9.92% of the total area. This biome is exclusively Brazilian and very rich in biodiversity. Because it has low resistance to human interference is necessary to know the important factors in monitoring the biome. Vegetation coverage and climate are two of these factors, as they indicate the intensity of human activity and the wear caused with time. Normalized Difference Vegetation Index (NDVI) has been recently explored in the description of tree phenology. In this study we sought to associate NDVI/Landsat values to a climatic variable (phenomena El-Nino and La-Nina - NINONINA) in order to describe the phenological behavior of the Caatinga in the Parque Nacional da Serra das Capivaras in the state of Piauí/Brazil. A time series analysis was carried out, describing the intrinsic parameters of the series (Seasonality and Trends), the forecast of NDVI values using SARIMA model and co-integration between NDVI and NINONINA series. The results showed that the NDVI series presents seasonally, but does not exhibit a trend. The forecasting process presenting relatively low error at a 95% confidence interval. Finally, it was observed that the NDVI series is co-integrated with the NINONINA series.

Resumo em Inglês:

ABSTRACT The present study considered the effect of nanosilica levels on the thermal, flammability, and morphological properties of nanocomposites made of wood flour and recycled polystyrene. To do so, the recycled polystyrene (50%), wood flour (50%), nanosilica (four levels of nanosilica; 0, 2, 4 and 6 phc (parts per hundred compounds)), and maleic anhydride, grafted with polypropylene (at a constant level of 3 phc) were mixed by a twin-screw extruder; then standard experimental samples were made using a hand pressing method. Next, the thermal and flammability properties were measured. The results showed that increasing of nanosilica content to 6 phc by weight increased thermogravimetric analysis (TGA) of nanocomposites; in addition, the limited oxygen index increased. Moreover, scanning electron microscopy (SEM) indicated that an increasing of nanosilica increased compatibility so that better link and adherence was observed among the fiber and matrix material.

Resumo em Inglês:

ABSTRACT Honey production forests (HPFs) are crucial forest areas for the preservation and transfer of biodiversity for future generations, provision of sustainable food safety, supporting rural development, and the rehabilitation of barren forests so that society can benefit from them. The purpose of this study is to prepare a model for conducting planning and prioritizing for HPF areas. For this purpose, using a multidimensional decision support model, we determined the most suitable three areas by way of prioritizing potential HPF areas identified. Bartın in Turkey which was chosen as the area of study, in line with the criteria (ecological-environmental, economic, and socio-cultural) set out using the participatory approach. The ranking and analytic hierarchy process (AHP) methods were employed. The results of the study indicate that public institutions and non-governmental organizations (NGOs) prioritize ecological-environmental criteria (especially the type of honey) in their identification of HPFs, whereas the locals care more about the economic criteria, especially the potential for honey production, when identifying HPFs. Moreover, the fact that the level of demand is at the top among the economy-based sub-criteria indicates that the demands and expectations of interest groups should definitely be taken into consideration in the functional provision of forest resources. If HPF areas are planned and established by paying attention to the priorities, HPFs would contribute to an increase in added value and social welfare in the local area as well as to employment, rural development, and the sustainable management of forest resources.