Portable Hardness tester for timber classification

Hardness is a property largely used in material specifications, mechanical and metallurgical research and quality control of several materials. Specifically for timber, Janka hardness is a simple, quick and easy test, with good correlations with the compression parallel to grain strength, a strong reference in structural classification for this material. More recently, international studies have reported the use of Brinell hardness for timber assessment which resumes the advantages previously mentioned for Janka hardness and make it easier to be performed in the field, especially because of the lower magnitude of the involved loads. A first generation of an equipment for field evaluation of hardness in wood - Portable Hardness tester for wood - based on Brinell hardness has already been developed by the Research Group on Forest Products from FCA/UNESP, Brazil, with very good correlations between the evaluated hardness and several other mechanical properties of the material when performing tests with different species of native and reforested wood (traditionally used as ties - sleepers - in railways). This paper presents results obtained in the experimental program with the first generation of this equipment and preliminary tests with its second generation, which uses accelerometers to substitute the indentation measurements in wood. For the first generation of the equipment functional and calibration tests were carried out using 16 native and reforestation timber lots, among there E. citriodora, E. tereticornis, E. saligna, E. urophylla, E. grandis, Goupia glabra and Bagassa guianenses, with different origins and ages. The results obtained confirm its potential in the classification of specimens, with inclusion errors varying from 4.5% to 16.6%.

The formation of the professionals for the timber industrial sector of the civil construction

The common point between the two forms of production of the wood-based sector in Brazil, one practically manufacturing and the other high technology, is in the qualification of the of the labor. In both cases, the professionals are being formed directly in the productive line and rarely with qualification in the academic area. There is not a public political education for the qualification of the labor, and the work market that does not demand qualified professionals, contributes for the sector stagnation. So, in order to excel the socio-cultural barriers in relation to the use of wood in the buildings, new attitudes are necessary in the teaching of the contents of the curricular programs, mainly, in formation of the architect and civil engineering.

Structure of a novel class II phospholipase D: Catalytic cleft is modified by a disulphide bridge

Phospholipases D (PLDs) are principally responsible for the local and systemic effects of Loxosceles envenomation including dermonecrosis and hemolysis. Despite their clinical relevance in loxoscelism, to date, only the SMase I from Loxosceles laeta, a class I member, has been structurally characterized. The crystal structure of a class II member from Loxosceles intermedia venom has been determined at 1.7. Å resolution. Structural comparison to the class I member showed that the presence of an additional disulphide bridge which links the catalytic loop to the flexible loop significantly changes the volume and shape of the catalytic cleft. An examination of the crystal structures of PLD homologues in the presence of low molecular weight compounds at their active sites suggests the existence of a ligand-dependent rotamer conformation of the highly conserved residue Trp230 (equivalent to Trp192 in the glycerophosphodiester phosphodiesterase from Thermus thermophofilus, PDB code: 1VD6) indicating its role in substrate binding in both enzymes. Sequence and structural analyses suggest that the reduced sphingomyelinase activity observed in some class IIb PLDs is probably due to point mutations which lead to a different substrate preference. © 2011 Elsevier Inc.

Can overharvesting of a non-timber-forest-product change the regeneration dynamics of a tropical rainforest? The case study of Euterpe edulis

The exploitation of non-timber forest products is often considered a low-impact activity in tropical forests. However, assessments of the impacts of such activity are mostly focused on the harvested species and not on the plant community, thus limiting our understanding for establishing forest management recommendations. We investigated the consequences of Euterpe edulis palm heart harvesting on the seed rain in the Brazilian Atlantic rainforest. We compared the density of E. edulis individuals, as well as the density of E. edulis seeds, and the density, richness and functional composition of seed rain of the whole plant community, before and after palm heart harvesting in a 10 ha permanent plot. This assessment was carried out in preserved (typical old-growth Atlantic rainforest) and in disturbed (more open habitat dominated by the native bamboo Guadua tagoara) forest patches. Palm harvesting reduced the E. edulis population from 202.16 to 25.67 ind/ha and its seed rain density from 0.362 to 0.3 seeds/m2 and from 2.395 to 0.15 seeds/m2 in preserved and disturbed forest patches, respectively. Seed density of light-dependent climbers, pioneer trees, bamboo and animal-dispersed seeds increased after palm harvesting, especially in the disturbed forest patches, where palm harvesting was more intense and may have changed the light regime of the understory. On the other hand, species richness of the plant community declined by half. We observed a remarkable decline in the number of animal-dispersed species, especially for those with large seeds, suggesting that the activity of seed dispersers, including many species attracted by E. edulis fruits, was reduced. Therefore, harvesting of E. edulis palm heart may change the regeneration dynamics of the Atlantic rainforest, both due to shifts in forest structure, mediated by the removal of individuals from the forest canopy, and in community functioning, mediated by the interference on the activity of seed dispersers. © 2013 Elsevier B.V. All rights reserved.

Reproductive phenology and fruit production on a land bridge island in the brazilian atlantic forest

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ponte mista de madeira-concreto em vigas treliçadas de madeira

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Report of survey on six CDCC countries regarding the development of the timber industry at the sub-regional level

Includes bibliography

La evaluación social de proyectos y la estimación del impacto ambiental: un puente teórico necesario pero complicado = Social project appraisal and environmental impact assessment: a necessary but complicated theoretical bridge

Incluye Bibliografía

Endodontics pastes formulated with copaiba oil: action on oral microbiota and dentin bridge formation in dogs

This study analysed the effect of pastes formulated with calcium hydroxide P.A. and different vehicles (saline solution - paste A and Copaifera langsdorffii Desfon oil - paste B) on oral microorganisms and dentin bridge formation in dogs. The antimicrobial action of the pastes and their components was analysed by the minimum inhibitory concentration in agar gel technique. The components were diluted and tested on fifteen standard strains of microorganisms associated with endodontic diseases. The microorganisms were cultivated and after incubation data was analysed using One-Way ANOVA and Turkey's test (P≤0.05). Four superior incisors of ten animals were used to evaluate dentin bridge formation. Two incisors were capped with paste A (GA) and two with paste B (GB). After 90 days, the teeth were extracted for histological analysis and the degree of dentin bridge formation evaluated. Data was analysed by the Kruskal-Wallis test (P<0.05). The pastes and their components were classified in the following decreasing order of antimicrobial action: calcium hydroxide P.A., paste A, paste B and Copaifera langsdorffii Desfon oil. Calcium hydroxide P.A. showed significantly higher antimicrobial action than the pastes or their vehicles. No significant difference was observed between the two pastes in dentin bridge formation. Based on the microorganisms studied, it can be concluded that the pastes analysed showed similar antimicrobial potential but differed significantly from their individual components. No significant difference was observed in dentin bridge formation between the different pastes tested.

Impact of Bottom Flange Confinement Reinforcement on Performance of Prestressed Concrete Bridge Girders

For many years AASHTO provided no recommendation to state DOT’s on bottom flange confinement reinforcement for their bridge superstructures. The 1996 edition of AASHTO Standard Specification for Highway Bridges stated that nominal reinforcement be placed to enclose the prestressing steel from the end of the girder for at least a distance equal to the girder’s height. A few years later the 2004 AASHTO LRFD Bridge Design Specification changed the distance over which the confinement was to be distributed from 1.0h to 1.5h, and gave minimum requirements for the amount of steel to be used, No.3 bars, and their maximum spacing, not to exceed 6”. Research was undertaken to study what impact, if any, confinement reinforcement has on the performance of prestressed concrete bridge girders. Of particular interest was the effect confinement had on the transfer length, development length, and vertical shear capacity of the fore mentioned members. First, an analytical investigation was performed on the subject, and then an experimental investigation followed which consisted of designing, fabricating, and testing eight tee-girders and three NU1100 girders with particular attention paid to the amount and distribution of confinement reinforcement placed at the end of each girder. The results of the study show: 1) neither the amount or distribution of confinement reinforcement had a significant effect on the initial or final transfer length of the prestress strands; 2) at the AASHTO calculated development length, no significant impact from confinement was found on either the nominal flexural capacity of bridge girders or bond capacity of the prestressing steel; 3) the effects from varied confinement reinforcement on the shear resistance of girders tested was negligible, however, distribution of confinement did show to have an impact on the prestressed strands’ bond capacity; 4) confinement distribution across the entire girder did increase ductility and reduced cracking under extreme loading conditions.