Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where João Vicente de Figueiredo Latorraca is active.

Publication


Featured researches published by João Vicente de Figueiredo Latorraca.


Anais Da Academia Brasileira De Ciencias | 2011

Chemical composition and natural durability of juvenile and mature heartwood of Robinia pseudoacacia L.

João Vicente de Figueiredo Latorraca; Oliver Dünisch; Gerald Koch

The aim of this study was to characterize the properties of juvenile and mature heartwood of Robinia pseudoacacia L. (black locust). The content, the composition, and subcellular localization of heartwood extractives were studied in 14 old-grown trees from forest sites in Germany and Hungary, as well as in 16 younger trees of four clone types. Heartwood extractives (methanol and acetone extraction) were analysed by HPLC-chromatography. UV microspectrophotometry was used to localize the extractives in the wood cell walls. The natural durability of juvenile and mature heartwood was analysed according to the European standard EN 350-1. Growth analyses, as well as the chemical analyses, showed that in Robinia the formation of juvenile wood is restricted to the first 10-15 years of cambial growth. In the heartwood high contents of phenolic compounds and flavonoids were present, which were in high concentrations in the cell walls of the axial parenchyma and of the vessels. In the juvenile heartwood, the content of these extractives is significantly lower than in the mature heartwood. In agree, the juvenile heartwood had a lower resistance to decay by Coniophora puteana (brown rot fungus) and Coriolus versicolor (white rot fungus) compared to the mature.


Anais Da Academia Brasileira De Ciencias | 2009

A supramolecular proposal of lignin structure and its relation with the wood properties

Heber dos Santos Abreu; João Vicente de Figueiredo Latorraca; Regina Paula Willemen Pereira; Maria Beatriz de Oliveira Monteiro; F Abreu; Kelysson de Freitas Amparado

In spite of the great importance of cellulose the lignin is considered the second most abundant substance of the wood. However, little attention has been given it, mainly to wood properties. The lignin as well as other structural compounds (cellulose and hemicelluloses), has obviously an important role on the wood properties, probably due its composition and existent bonds. In general lignins have beta-O-4 (Alkyl Aril Ether) as majoritary bond. This bond in a continued structure form big molecules with spiral conformation as virtual model. Based on this idea, lignins that have high/low beta-O-4 content may have differentiated spiraled structures,suggesting different behaviors on the wood properties,which shows that the lignins (Guaicyl:Syringyl (GS)) of angiosperms, for example, which have higher beta-O-4 content would present higher spiral conformation than gymnosperms lignins(HG). On the other hand HG lignins have chance of being more anchored on the matrix compound than GS lignins. In this context, the beta-O-4 bonds of lignins possibly affect the wood properties, therefore, it is considered relevant for wood technology science discussion.


Maderas-ciencia Y Tecnologia | 2014

Surface roughness of heat treated Eucalyptus grandis wood

Gilmara Pires de Moura Palermo; João Vicente de Figueiredo Latorraca; Luiz Fernando de Moura; Adriana Maria Nolasco; Alexandre Monteiro de Carvalho; Rosilei Aparecida Garcia

This study aimed to evaluate surface roughness of heat treated Eucalyptus grandis wood after peripheral planning and sanding performed in directions to the grain and against the grain. For machining tests, workpieces were collected from two different regions in the radial direction, as follows: internal, nearby the pit; external, nearby the bark. Heat treatment was carried out by heating samples at a maximum temperature of 190oC, with total treatment duration of 390 minutes. Heat treated and control samples underwent peripheral planning and sanding tests. The quality of machined surfaces was assessed by means of roughness average (Ra) measurements across and along the grain orientation. Results indicated significant differences in surface roughness as a function of machining feed direction, sandpaper grit size, and heat treatment. Surface roughness has not shown any difference in the radial direction.


Revista Arvore | 2010

Correlações da altura e diâmetro com tensões de crescimento em árvores de Corymbia citriodora e Eucalyptus urophylla

Alexandre Monteiro de Carvalho; Maria da Penha Moreira Gonçalves; Kelysson de Freitas Amparado; João Vicente de Figueiredo Latorraca; Rosilei Aparecida Garcia

The multiple-use of planted forests by the forest products industrial sector has been increased gradually. Today, eucalyptus wood is used for nobler applications. However, some limitations, such as the presence of growth stresses, are responsible for great losses in the sector. Growth stresses generate cracks in the tops of logs and boards followed by warping. In this context, the objectives of the present work were to evaluate the growth stresses in individual Corymbia citriodora and Eucalyptus urophylla with different diameter and height classes, by the longitudinal residual strain (LRS) nondestructive method, around the trees circumference. The average longitudinal residual strain, associated to the Corymbia citriodora and Eucalyptus urophylla growth stresses, were 0.106 and 0.092 mm, respectively. For Corymbia citriodora, the diameter at breast height (DBH) had a negative significant correlation with the LRS, while the height did not show a significant correlation. For Eucalyptus urophylla, a negative significant correlation between LRS and both variables, DBH and height, was observed. Indeed, growth stresses were lower for greater DBH and heights.


Maderas-ciencia Y Tecnologia | 2014

Color stability of weathered heat-treated teak wood

Rosilei Aparecida Garcia; Juliana de Oliveira Lopes; Alexandre Miguel do Nascimento; João Vicente de Figueiredo Latorraca

This study investigated the color stability in a heat treatment of teak wood (Tectona grandis) exposed to ultraviolet radiation under accelerated aging conditions. Nine trees from three different spacing levels were used. Samples of 150 mm x 75 mm x 20 mm were prepared and divided into two groups: heartwood and sapwood. Two levels of heat treatment (180 and 200°C) were used. The color was measured every 42 hours with a portable spectrophotometer using the CIE-Lab system. Accelerated aging was performed in a QUV/Spray chamber. The total cycle of exposure to ultraviolet radiation was of 168 hours at 340 nm. Tree planting spacing had no effect on color change after ultraviolet radiation. Untreated sapwood had greater color change than untreated heartwood. However, after heat treatment, sapwood showed high color stability, especially at a temperature of 180°C.


Revista Arvore | 2013

Delimitação entre os lenhos juvenil e adulto de Pinus elliottii engelm

Gilmara Pires de Moura Palermo; João Vicente de Figueiredo Latorraca; Elias Taylor Durgante Severo; Alexandre Miguel do Nascimento; Marcos Antônio de Rezende

RESUMO – Durante o crescimento, as arvores produzem diferentes tipos de tecido lenhoso. O xilema produzido nos primeiros anos ate certa idade cambial e denominado lenho juvenil e apresenta propriedades fisicas, mecânicas, quimicas e anatomicas diferentes do xilema produzido apos certa idade cambial, isto e, quando as celulas do câmbio ja amadureceram. Dessa forma, um previo conhecimento sobre a qualidade da materia-prima produzida e de fundamental importância para melhor aplicabilidade do material. Com base nesse contexto, este trabalho objetivou, a partir de dados de comprimento de traqueideos e densidade da madeira, delimitar a idade de transicao entre os lenhos juvenil e adulto. Para isso, coletaram-se tres arvores de Pinus elliottii var. elliottii Engelm., com 35 anos de idade, provenientes da Estacao Experimental de Itapetininga, localizada em Sao Paulo, Brasil. De cada arvore, retiraram-se discos de aproximadamente 5 cm de espessura, extraidos a 0,05 m do solo, que foram utilizados para determinacao radial da densidade pelo metodo de atenuacao da radiacao gama e comprimento dos traqueideos. Os resultados da analise de regressao linear indicaram que o lenho juvenil esta limitado aos sete primeiros anos de crescimento da arvore e o lenho adulto e formado apos os 20 anos de idade. No lenho adulto ha diferencas significativas entre as idades medias obtidas atraves do comprimento dos traqueideos e da densidade da madeira.


Revista Arvore | 2006

Efeito de aditivos minerais sobre as propriedades de chapas cimento-madeira

Gilmar Correia Silva; João Vicente de Figueiredo Latorraca; Jair Figueiredo do Carmo; Érika da Silva Ferreira

The objective of this work was to evaluate the effect of the two minerals additives (microsilica and meta-kaolin) on the properties of wood cement-bonded particleboard (WCBP) with different amounts (0%, 20% and 30%) of additives. Portland cement of high initial resistance was used in the production of panels as binder material. It was mixed with Eucalyptus urophylla wood particles to boards formation. The results indicated that the addition of mineral additives did not cause significant improvements in the evaluated mechanical properties. For physical properties, the positive effect of the addition of 20% microsilica can be observed on the absorption in water properties after 2 and 24 hours. The additive meta-kaolin did not present a clear trend, but, in general, the addition of this additive caused a reduction in the quality of boards.


Ciencia Florestal | 2011

Correlações dendroclimatológicas do Eucalyptus grandis Hill ex Maiden na região de Rio Claro, RJ

Bruna Roque Ugulino de Oliveira; João Vicente de Figueiredo Latorraca; Mario Tomazello Filho; Rosilei Aparecida Garcia; Alexandre Monteiro de Carvalho

The commercial forests plantation contributes decisively to generate socio-economic and environmental benefits, providing sustainability at the forest-based industries. The Eucalyptus grandis Hill ex Maiden stand out as one of the most cultivated species for reforestation in Brazil. The objective of this study was to determine the relationship between precipitation and wood production for 23-year old Eucalyptus grandis from a commercial plantation in Rio Claro, Rio de Janeiro state, Brazil. The annual increment of wood was determined by the X-ray densitometry, which provides a detailed wood density profile in radial direction for each sample. One year of the tree life was considered because this the period for the formation of two consecutive latewood rings formation, which corresponds to two high density peaks. The results showed a positive correlation between precipitation data and annual increment of wood, revealing the dendroclimatology potential of this species in this region.


Journal of Wood Chemistry and Technology | 2016

Copaifera langsdorffii Bark as a Source of Chemicals: Structural and Chemical Characterization

Jair Figueiredo do Carmo; Isabel Miranda; Teresa Quilhó; Vicelina B. Sousa; Sofia Cardoso; Alexandre Monteiro de Carvalho; Fábio Henrique Della Justina do Carmo; João Vicente de Figueiredo Latorraca; Helena Pereira

The chemical composition and the anatomy of Copaifera langsdorffii bark are reported here for the first time by studying trees grown in a native forest area in the Amazon region, Brazil. The bark is thin, dark reddish brown, and exfoliates in irregular flakes. It is very dense, showing highly lignified cells and abundant sclereids, and cellular fillings of phenolic nature. It includes a poorly developed rhytidome and a periderm with thin- and thick-walled phellem cells. The mean chemical composition was: ash 3.7%, total extractives 21.3%, mainly corresponding to polar compounds soluble in ethanol and water, suberin 0.8%, and lignin 36.6%. The polysaccharides showed a predominance of glucose and xylose (66.4% and 23.5% of total monosaccharides, respectively). The ethanol-water bark extract had a high content in phenolics: total phenolics 589.2 mg gallic acid/g extract, flavonoids 441.9 mg catechin/g extract, and tannins 54.8 mg catechin/g extract. The antioxidant activity was high, comparable to known antioxidant reference compounds: 720.3 mg Trolox per g of extract or 92.1 mg Trolox per g of bark. After bark grinding, the finest fraction was enriched in polar extractives (40.6%). C. langsdorffii bark is a potential source of functional extractives, therefore representing a valorization of the residual bark obtained during the industrial tree processing for timber.


Floresta e Ambiente | 2016

Impact of Site Conditions Changes on the Tree Ring Records Suitability as Climate Proxies in the Brazilian Amazon

Oliver Dünisch; João Vicente de Figueiredo Latorraca

The increment zones width in the xylem of Swietenia macrophylla King was investigated by dendrochronological methods in an undisturbed and a strongly disturbed tropical site near Aripuana, Mato Grosso, Brazil (10°09’ S, 59°26’W). The study aimed to assess the impact of forest disturbance on the relationship between precipitation and the cambial growth of this species. Tree-ring width chronologies were developed for both sites from cross-dated increment curves. Simple correlations were computed between monthly precipitation records and the annual increment of Swietenia for the period between 1870 and 2000. Logging activities and altered land use caused a significant decrease of the water supply of the Swietenia trees grown in the disturbed area compared to trees grown in the undisturbed area. Consequently, the precipitation of almost the total growing season had a significant influence on the tree ring width of Swietenia grown in the disturbed area, while in the undisturbed forest area the significant correlation between monthly precipitation and the tree ring width of Swietenia was restricted to the beginning of the growing season (November to January). However, the reconstruction of monthly precipitation data from the tree ring width records was more precise using the chronology developed from tree ring width records of undisturbed trees compared to the chronology developed from tree ring widths from the disturbed area. It was concluded that the use of the tree ring widths of Swietenia as climate proxies is restricted to certain months of the year and requires tree ring width chronologies developed from trees grown in undisturbed or only slightly disturbed forest areas without severe anthropogenic changes in microclimate.

Collaboration


Dive into the João Vicente de Figueiredo Latorraca's collaboration.

Top Co-Authors

Avatar

Alexandre Monteiro de Carvalho

Universidade Federal Rural do Rio de Janeiro

View shared research outputs
Top Co-Authors

Avatar

Rosilei Aparecida Garcia

Universidade Federal Rural do Rio de Janeiro

View shared research outputs
Top Co-Authors

Avatar

Jair Figueiredo do Carmo

Universidade Federal Rural do Rio de Janeiro

View shared research outputs
Top Co-Authors

Avatar

Alexandre Miguel do Nascimento

Universidade Federal Rural do Rio de Janeiro

View shared research outputs
Top Co-Authors

Avatar

Juliana de Oliveira Lopes

Universidade Federal Rural do Rio de Janeiro

View shared research outputs
Top Co-Authors

Avatar

Letícia Maria Alves Ramos

Universidade Federal Rural do Rio de Janeiro

View shared research outputs
Top Co-Authors

Avatar

Gilmara Pires de Moura Palermo

Universidade Federal Rural do Rio de Janeiro

View shared research outputs
Top Co-Authors

Avatar

Heber dos Santos Abreu

Universidade Federal Rural do Rio de Janeiro

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

José Henrique Camargo Pace

Universidade Federal Rural do Rio de Janeiro

View shared research outputs
Researchain Logo
Decentralizing Knowledge