Wood is a material widely used in various sectors of construction, such as in structures and building components. The volume of wood extracted from tropical forests has reached a considerable amount, and this wood is marketed with popular names without prior characterization. Wood density is an easy property to measure, and its use as an estimator of other properties is very common in this sector. This study investigated the possibility of the estimation of important quantities in dimensional stability of Brazilian tropical woods by using the density at 12% moisture content, anhydrous density, and basic density. Testing the ability to estimate radial, axial, tangential, and volumetric shrinkage, anisotropy coefficient, coefficient of volumetric rate of volumetric shrinkage, as well as the rate of volumetric swelling using the densities above, with linear, exponential, geometric, and logarithmic models, the best determination coefficient was: R 2 = 19.58%. The results were, in summary, that the variable density was not a good estimator of the dimensional stability of the wood.

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We present coordinates and available photometric information (either from previous or recent broadband UBV observations, and near-infrared photometry from the 2MASS Point Source Catalog) for 12,056 stars (11,516 of which are unique) identified in the HK Survey of Beers and colleagues as candidate field horizontal-branch or A-type stars. These stars, in the apparent magnitude range 10 B 16:0, were selected using an objective-prism/interferencefilter survey technique. The availability of 2MASS information permits assembly of a cleaned version of this catalog, comprising likely blue horizontal-branch (BHB) stars or blue stragglers in the color interval [À0:2 (B À V ) 0 þ0:2], which are of particular interest for investigation of the structure, kinematics, and dynamics of the thick disk and inner halo of the Milky Way, the total mass and mass profile of the Galaxy, and as potential foreground/background objects in efforts to bracket distances to high-velocity clouds of H i. A comparison of the stars classified as highlikelihood BHB candidates with previous classifications based on UBV photometry and medium-resolution spectroscopy indicates that this class contains 78% correct identifications.

The knowledge about anisotropy of wood possibility more security design of structures and structural members designed. Therefore, there are little quantity of results knowledge about shrinkage and anisotropy coefficients of Wood species, motivating the development of new researches. The aim of research is evaluate the possibility of estimate the full shrinkage (radial; tangential; volumetric), anisotropy coefficient and shrinkage coefficient (radial; tangential; volumetric), using polynomial regression models (linear; quadratic; cubic) and exponential, by density of five Wood species (Cedro Doce [C20]; Canafístula [C30]; Angelim Araroba [C40]; Mandioqueira [C50]; Angelim Vermelho [C60]), properly classifieds in five strength classes for dicotyledonous according Brazilian Standard ABNT NBR 7190:1997. The better results were from tangential and volumetric retractions both using exponentials functions, justified by lower values of variation coefficients, with coefficients values of determination adjusted ranging from 51 and 54%. Even considered significant to the regressions for the tangential and volumetric shrinkage by analysis of variance, but with adjusted coefficients of determination lower than 70%, news researches should realized with other Wood species, enabling find general expressions for estimating such properties using the knowledge of the density.

Shrinkage and coefficient of anisotropy are fundamental physical parameters in analysis of dimensional stability of timber structures members. In Brazil, properties of wood are obtained according to assumptions and calculation required by Annex B of ABNT NBR 7190: 1997 (Timber Structures Design). Among the physical properties, density appears as the easiest one to be experimentally obtained, defined by ratio between mass of the sample and its volume. To evaluate the possibility of estimating shrinkage (longitudinal, RL; radial, RR; tangential, RT; volumetric, RV; and coefficient of anisotropy, CA) of wood depending on density, this study aimed to test regression models (linear, exponential, logarithmic, geometric) using basic density (ρ bas ) and apparent density (ρ 12 ) as independent variables. For this purpose, five wood species belonging to conifers: Pinus sp., Pinus oocarpa; and dicotyledonous: Paricá (Schizolobium amazonicum), Jatobá (Hymenaea sp.) and Lyptus®, were employed. In all, 23 samples for Pinus sp.; 15 for Pinus oocarpa; 28 for Paricá; 16 for Lyptus®; and 11 for Jatobá were produced, totaling 651 determinations. Results of analysis of variance for regression models indicated insignificance of the adjustments obtained by adopting densities as estimators of shrinkage and coefficient of anisotropy for this set of wood species. Only models involving basic density and apparent density were significant, wherein the optimal settings were from linear case, exhibiting coefficient of determination (R 2 ) 91.72% (for softwoods) and 83.36% (for hardwoods).

Este trabalho tem com objetivo avaliar a integridade das estruturas que fazem parte da cobertura de um galpão de 70 anos, destinado ao estoque de produtos químicos, localizada no Estado de São Paulo (Brasil), e apontar possíveis soluções para os problemas identificados. Buscou-se estimar a influência dos resíduos dos produtos químicos depositados nas superfícies dos elementos estruturais e identificar a espécie de madeira utilizada no projeto, por meio de ensaios físicos (densidade aparente) e mecânicos (compressão e cisalhamento paralelo às fibras. Os problemas identificados foram: (a) umidade devido a telhas quebradas; (b) deterioração superficial da madeira em função de reação química entre os produtos armazenados e a estrutura; (c) cavilhas de madeira com instalação incompleta; (d) falta de mãos-francesas em algumas terças; (e) travamento inadequado das treliças; e (f) deterioração de pregos de fixação por oxidação. Pelas observações realizadas, as soluções indicadas são de fácil execução, pois as estruturas não foram severamente prejudicadas. Com relação à espécie de madeira, os resultados das propriedades mecânicas obtidas associadas à densidade aparente apontaram para a espécie Peroba-Rosa (Aspidosperma polyneuron). A análise estatística de resultados apontou para a não influência do produto químico no desempenho da estrutura do telhado.

The aim of this research is determining mechanical properties of Paricá wood specie (Schizolobium amazonicum Herb) using structural and clear specimens, according to Brazilian standard ABNT NBR 7190 requirements. Paricá wood specie in structural members, with moisture content of around 12%, were determined dynamic elasticity modulus (transverse vibration tests), static bending modulus (three point bending) and modulus of rupture in static bending test. In clear specimens, according to Brazilian standard were determined compression, shear, embedment and tension parallel to the grain, and the elasticity modulus in compression and tension parallel to the grain. It is concluded that the Paricá wood specie present good strengths properties, although of low density, presenting potential for use in timber structures.