Papers by Emilin J da Silva
Floresta e Ambiente, 2019
Revista Ciência da Madeira - RCM, 2019
Wood color and properties are variables among and within species, and fast and non-destructive te... more Wood color and properties are variables among and within species, and fast and non-destructive techniques can be applied to their characterization, being also important in wood marketing and quality control. This paper evaluated the influence of age on the discrimination of Tectona grandis L.F. (teak) wood by VIS/NIR spectroscopy. Wood from three ages, with heartwood and sapwood, were studied, totaling 36 samples per age. Quantitative colorimetric data, based on CIELAB 1976, visible and NIR infrared spectra were collected from radial and tangential surfaces in five positions of each sample, in a total of 540 spectra. Both techniques were adequate for age discrimination in teak wood. Statistical differences were observed in the chromatic coordinates in heartwood and sapwood for each age. VIS/NIR spectroscopy can be applied for age discrimination based on teak solid samples and for wood quality control.
Eucalyptus grandis wood was thermally treated at two different temperatures (150 °C and 200 °C) i... more Eucalyptus grandis wood was thermally treated at two different temperatures (150 °C and 200 °C) in a muffle furnace with steam. The surface color change was measured right after the treatment and in wood samples stored for two years inside a carton box without light exposure. Samples were analyzed by thermogravimetry to detect variations of thermal degradation behavior for different treatment temperatures. Thermally treated wood was darker when compared to control samples. The storage time influenced the wood surface color, with the surface becoming darker and redder. Thermogravimetric analysis revealed a peak of wood degradation between 300 °C and 400 °C for thermally treated samples.
Scientia et Technica, 2021
Heat treatments are carried out on the wood to modify the hygroscopic properties and its dimensio... more Heat treatments are carried out on the wood to modify the hygroscopic properties and its dimensional stability. This allows low-grade wood to be used in exposed applications. This document provides a systematized bibliographic review related to the available technologies that allow heat treatment of wood. For this, scientific databases were consulted where previous studies with high temperature drying were found that served as the basis for the development of technologies that are used today. Patent databases were also consulted making the systematic use of the International Patent Classification (IPC) and Cooperative Patent Classification (CPC), the most promising codes were selected according to the histogram analysis. Finally, a marked trend was observed in recent years in the study and development of heat treatments applied to different timber species.
Este breve estudo teve como objetivo comentar as caracteristicas principais ao empreendedorismo r... more Este breve estudo teve como objetivo comentar as caracteristicas principais ao empreendedorismo rural no Brasil. Foram selecionados, em periodicos brasileiros, nove artigos que tiveram como tema central o empreendedorismo rural nacional. As publicacoes ocorreram entre os anos de 2002 e 2014. Cada artigo da amostra e unico, por mais que o tema central seja o mesmo. Os objetivos dos artigos da amostra diferem muito entre si, desde a metodologia aplicada, localizacao geografica do cenario analisado nos estudos ate mesmo as conclusoes. Foi possivel, porem detectar um impasse generico ao empreendedorismo rural, referente ao incentivo governamental e a falta de competencias empreendedoras como, por exemplo, habilidades em gestao de negocios. O cenario brasileiro atual proporciona cada vez mais ambientes voltados ao desenvolvimento em inovacao e empreendedorismo. Mesmo assim, o pais tem muito que trabalhar para promover a atitude empreendedora com eficiencia, se assim o quiser.
Heat treatment of wood is well known to enhance its resistance against biodegradation. This is an... more Heat treatment of wood is well known to enhance its resistance against biodegradation. This is an effect of the lower equilibrium moisture content, caused by the thermal degradation of structural wood components. At the same time, mechanical properties are known to decrease with temperature and treatment duration. In the study at hand, samples of Uruguayan Eucalyptus grandis (W. Hill ex Maiden) were thermally modified in two different temperature regimes, with distinct time for each heat treatment. We found the hygroscopicity to be reduced. Elasticity was not altered significantly by the heat treatment. Anyways, the maxima of compressive, bending and impact bending strengths decreased with increasing temperature. Brinell hardness showed be only slightly influenced by heat. Treated E. grandis substitute for typical tropical hardwood applications like deckings and outdoor utilization.
Conference Presentations by Emilin J da Silva
Population growth has consequences on bio‑resources consumption and waste production. The urbaniz... more Population growth has consequences on bio‑resources consumption and waste production. The urbanization pressure in Sub‑Saharan Africa skyrockets the demand for building materials such as concrete and wood. The BioHome project investigates the availability, accessibility, and competition demand for secondary resources in Ethiopia and South Africa. Resources such as wood and non-wood lignocellulosic materials (invasive species, agricultural residues, bamboo, municipal pruning, waste wood), post-consumer thermoplastics (PP, PE, PVC), and ashes (coal, slag, biomass) were surveyed. The Ethiopian building industry is a net importer. In 2017 wood and wood products imports (except pulp and paper) accounted for USD 73 million. Plastic import summed USD 634 million, of which roughly 70% may potentially be recycled. In 2015, the South African energy mix contained 77% mineral coal, i.e. 34.4 million tons of ashes. It is generally known that combustion residues are landfilled or utilized in low‑value products, e.g. concrete. The latest research showed that those industrial residues can be also utilized in wood‑plastic‑composites (WPC) and geopolymer‑wood‑composites (GWC) for instance. This study helps to contextualize the development of such building materials, value addition to secondary resources, and cooperation to reduce the trade deficit of building materials.
Female participation in paid work has increased in Europe over the last 20 years (Eurofound 2015)... more Female participation in paid work has increased in Europe over the last 20 years (Eurofound 2015) with labor markets often remaining gender-segregated (Mangubhai et al. 2022). This in particular holds true for the forest sector, which is still, to a large extent, male-dominated. Employment statistics of 37 European countries show that at least 2.6 million persons in 2019 were employed in the forest sector (forestry, manufacture of wood, manufacture of pulp and paper), with women accounting for only 18 % (ILO 2022). Besides the gender imbalance of the forest sector workforce, a wage gap between men and women is very likely. This is because women earn considerably less than their male colleagues in most economic sectors, particularly in gender-segregated ones (Leuze and Strauß 2016). While the wage gap between men and women has been well-researched, empirical evidence for the forest sector is still scarce. Hence, this study aims to assess the gender wage gap in the forest sector workforce in European countries. The results may support decision and policy processes in the forest sector towards reducing gender segregation and achieving gender equality in the long run.
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Papers by Emilin J da Silva
Conference Presentations by Emilin J da Silva