Resumo em Inglês:

Abstract Metal particles are used in abrasive blasting to provide cleaning, new shapes, or fatigue resistance to surfaces, depending on the format of these particles. However, these particulates constitute large amounts of waste with no proper treatment. In this scenario, this paper aims to compare two surface treatment methods using metallic particles on Pinus taeda wood: abrasive blasting and hot pressing. The size and shape of the particles were determined by scanning electron microscopy (SEM) and their chemical constitution by energy-dispersive X-ray spectroscopy (EDX). After each treatment, the wood surface was subjected to wettability and colorimetric tests. The hot pressing treatment and the copper slag particles provided the lowest wettability. The color changes were significant after both methods, highlighting their potential as a new finishing technique.

Resumo em Inglês:

Abstract Studies of plant phenology in the Atlantic Forest can be enhanced by a greater understanding of the factors regulating vegetative and reproductive cycles. Dalbergia nigra (Vell.) Allemão ex Benth. is endemic and vulnerable in the Atlantic Forest. We analyzed abiotic aspects and plant traits that modulate the phenologies of D. nigra by monitoring 135 individuals in four subpopulations from different remnant forests for 24 months. The growth and shapes of the plants, as well as environmental variables, were determined. Circular analysis evidenced phenological variations among subpopulations and evaluation periods. Multiple factor analysis evidenced that phenological variations are mainly correlated with precipitation, temperature, and tree height. The combination of environmental conditions and plant characteristics affect synchronicity and phenological intensity. Low fruiting intensity (less than 50%) limits seed production and recruitment. We emphasize the importance of forest remnants and the need to increase D. nigra populations in future reforestation projects.

Resumo em Inglês:

Abstract Founding new materials and structures for solar cells is a challenge in the photovoltaic field. This work evaluated the effect of the lignin in the photovoltaic activity by compounding with TiO2/lignin as photoanode for the dye sensitized solar cells (DSSC’s). Hybrid films (TiO2/lignin) with different concentrations of lignin (5, 10 and 15%) were deposited by spin coating over commercial TiO2 thin films. The cells were sandwich assembled. The characterizations were done through analysis of absorbance, band gap, x-ray diffraction, morphological and electrical. The lignin at 15% reduced the TiO2 band gap from 3.66 to 2.84 eV, favoring the short current density to 11.06 mA/cm2 and efficiency of 4.65%, an increase of 103.95% compared to the TiO2 structure without lignin.

Resumo em Inglês:

Abstract This study evaluated the effect of disinfestation methods and different storage environments on the germination of seeds of Limonium brasiliense (Boiss.) Kuntze. Seeds were disinfested using ethanol followed by sodium hypochlorite; water under agitation; and no disinfestation from two origins. Longevity was tested by storing the seeds in a cold chamber, dry chamber, and at ambient laboratory temperature. Beginning of germination (BG), percentage (%G), and mean germination time (MGT) and mean germination speed index (MGSI) were evaluated. Data were submitted to an analysis of variance, comparison of mean values and a polynomial regression analysis (p<0.05). In the disinfestation, there was significant difference in %G and MGT only between origins. For longevity, IG and MGSI had a positive and negative linear behavior, respectively, while %G had a quadratic behavior. L. brasiliense seeds disinfestation does not affect germination. Dry chamber was the most suitable storage environment.

Resumo em Inglês:

Abstract The current study aimed to evaluate the seed bank diversity and composition found in the Municipal Natural Park São Francisco de Assis (PSFA), Santa Catarina, Brazil, located within the subtropical Atlantic Forest. Samplings were carried out within four different locations (n = 20 sample plots per location). All samples were kept in suspended beds for germination, growth, and subsequent species identification. We were able to identify 85 morphospecies (1,016 individuals). Most of them were categorized as pioneers. Pioneers were also the ecological category that had more individuals (73.12%). The predominant dispersion syndrome was zoochoric, with 58 taxa included. Our results indicate that the seeds are being provided by species that occur around the park, in some cases favored by recent landslides in the area.

Resumo em Inglês:

Abstract The objective of this work was to evaluate the influence of colored shade mesh and plant density on the morphological characteristics of Corymbia citriodora seedlings. The highest radiation efficiency was found in the blue mesh, 7.01 g MJ-1 and 5.72 g MJ-1 for average and high density respectively. For dry matter and leaf area index at high density, the treatment without mesh followed by the red mesh was the best. The chlorophyll index did not differ between treatments, with mean values of 206.4, 59.1 and 262.0 for chlorophyll a, b and total, respectively. Using principal component analysis, we found the total variance to be 70%. The use of colored shade mesh and plant density altered the radiation use efficiency and dry matter accumulation. Leaf area index was affected only by plant density. The red mesh resulted in the most similar values to the treatment without mesh.

Resumo em Inglês:

Abstract This study aimed to verify technical potential of using waste from wood veneers and plywood as a raw material for the production of MDP. The variance analysis of the panels density was carried out. Physical-mechanical properties were evaluated by comparing them with the international standards and by analysis of variance. The averages were subjected to the analysis of covariance, at the level of 5% probability. Finally, Pearson’s correlation analysis between properties was performed. The panels produced with “log core” and “veneer clippings” residues showed equivalent averages for physical properties and higher for mechanical properties of internal bond and surface screw withdrawal, when compared the averages of panels produced with commercial particles. Panels produced with “plywood cutting” showed unsatisfactory mechanical properties. It’s concluded that the “log core” and “veneer clippings” residues show potential for use as a raw material in the composition of MDP.

Resumo em Inglês:

Abstract This study aims to determine the effect of nursery production time and container size on the quality standards of production of Simarouba amara seedlings based on nursery and field performance. The work was conducted in two phases: evaluation of nursery growth and field performance. A completely randomized design was used in both phases. Three container sizes (55, 180 and 280cm³) and four nursery production times (105, 125, 135 and 145 days) were tested. Height, collar diameter and survival were evaluated. S. amara seedlings can be produced in a 180 cm³ container with a maximum nursery production time of 125 days. The quality standard for seedlings corresponds to collar diameter ≥ 4.2 and height ≥ 9.1 cm.

Resumo em Inglês:

Abstract Half of the territory in Rio de Janeiro (RJ) state is composed of degraded areas. This work evaluated the profile, distribution, and production capacity of plant nurseries in RJ which produce forest seedlings, as well as their species’ richness. The potential to meet the increased demand arising from environmental commitments in different hydrographic regions was also analyzed. We identified 81 active forest seedling nurseries and 73 of them participated in our interview, by adopting a regional survey. Nearly one-third of the nurseries closed down in this region in the last decade. A high richness of species in the nurseries (977 species, 99 native species/nursery) was found, representing 22% of the regional flora. Most of this species’ richness is exclusively produced by small nurseries. The current production of the nurseries is capable of supplying less than 1% of the potential demand for seedlings for restoring priority watershed areas in the state.

Resumo em Inglês:

Abstract With the aim of using rustic species such as pequi (Caryocar brasiliense Camb) for the rational management of degraded areas of Northwestern state of Rio de Janeiro, two experiments were sequentially conducted. In the first, seed dormancy breaking was evaluated in an experiment conducted in a completely randomized design, with six treatments, three replicates and 10 seeds per plot. Treatments were combinations of seeds with or without scarification + gibberellic acid (GA) or water. Forty-five days after sowing, 73% germination was observed in treatment mechanical scarification + GA (MS+GA). In the second experiment seedlings obtained from treatment MS + GA were evaluated in the field, concurrently with a control. At 20 and 44 months, both treatments presented the same biometric characteristics and sixty-one months after planting, flowering began. Scarification following by treatment with GA anticipates seedlings production and did not compromise the performance of these seedlings in the post-planting period.

Resumo em Inglês:

Abstract Fourier transform infrared spectroscopy (FTIR) assists in investigating functional groups of soil organic matter (SOM). However, the use of this tool is impaired given the low organic carbon levels and high content of oxides in tropical soils, resulting in low quality spectra and in turn requiring the use of hydrofluoric acid (HF). The objective of this study was to verify the efficiency of using HF in removing the mineral fraction and to increase the C concentration to enable visualizing the bands related to SOM in infrared spectra in soil samples under forest system. The HF treatment was efficient in removing mineral components and proportionally increasing C. The FTIR with HF enabled identifying differences between coarse and fine fractions. The spectra of the HF samples showed that the coarse fractions presented bands related to aromatic material and the fine fractions presented more labile components, with the absence of more recalcitrant components.