Antinucleon spectra in the Dirac equation with scalar and vector Wood-Saxon potentials

We analyze here the spin and pseudospin symmetry for the antinucleon spectra solving the Dirac equation with scalar and vector Wood-Saxon potentials. In relativistic nuclear mean field theories where these potentials have large magnitudes and opposite signs we show that contrary to the nucleon case where pseudospin interaction is never very small and cannot be treated perturbatively, for antinucleon systems this interaction is perturbative and an exact pseudospin symmetry is possible. This result manifests the relativistic nature of the nuclear pseudospin symmetry. © 2009 American Institute of Physics.

Role of transitional levels in Np237 (γ,f): Perspectives for studying highly deformed systems

The transition levels at the top of the two Np237 fission barriers were obtained for the first time by means of the so-called semimicroscopic combined method, which we have developed and implemented. To overcome the difficulties in dealing with large nuclear deformations, we used our developed BARRIER code, which calculates single-particle spectra in a deformed Woods-Saxon potential using a coordinate system based on Cassini ovaloids as nuclear shape parametrization. The results enabled us to describe the experimentally observed near-barrier photofission cross-section structures for Np237, as well as a subbarrier shelf, the latter being consistently interpreted in terms of the accumulation of levels at the top of the inner and outer double fission barrier of Np237. © 2006 The American Physical Society.

Estimativas de parâmetros genéticos para caracteres quantitativos em progênies de polinização aberta de Eucalyptus urophylla

Eucalyptus urophylla S. T. Blake is outstanding for valuable wood production potential, adaptation plasticity for different environmental conditions, and for tolerance to canker. However, genetic improvement of this specie in Brazil depends on the existence of genetic variability in the introduced populations. The objective of this study was to investigate the genetic variation and gains in quantitative traits in a population established in 1992 in Selvíria - MS. The progeny trial was established in a partially balanced, 8 x 8 lattice design, with 64 families, collected at Anhembi Experimental Station (IPEF/ESALQ/USP). Each plot was made up of eight trees planted in a 3 × 3 m spacing. Significant among families genetic variations were observed in diameter at breast height (DBH), bark type, stem form, and survival. Estimates of average family heritability were high for all traits, ranging from 0.50 to 0.85. The simulated selection by using multi-effect index showed that under a varying number of plants per family. This method is the most indicated to maximize genetic gains (7.24%) and the effective population size (69.3). These results are a useful support for the transformation of this test into a seedling seed orchard and to become a source of vegetative material to build a clonal seed orchard.

Equações alométricas em plantios mistos visando à restauração da floresta estacional semidecidual

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Qualidade da madeira de árvores de guapuruvu (schizolobium parahyba (vell.) blake) com 15 anos provenientes de área de recuperação florestal

Pós-graduação em Ciência Florestal - FCA

Potential for using through-boring to improve groundline treatment of Australian wood species: A preliminary study.

An aging electricity distribution system and reduced availability of naturally durable tropical hardwoods in Australia will combine in the next decade to produce a major shortage of poles. One approach to mitigating this shortage is to utilize lower durability species and improve the penetration of preservatives into the refractory heartwood by introducing additional pretreatment processes. A potential method for improving preservative penetration in the critical ground-line zone is through-boring. This process, in which holes are drilled through the pole perpendicular to the grain in the ground-line zone, is widely used in the western United States for treatment of Douglas-fir and may be Suitable for many Australian wood species. The potential for improving heartwood penetration in eucalypts with alkaline-copper-quaternary (ACQ) compound was assessed on heartwood specimens from four species (Eucalyptus cloeziana F.Muell., E. grandis W.Hill ex Maiden, E. obliqua L'Her. and E. pellita F.Muell.) and Lophostemon confertus (R.Br.) Peter G.Wilson & J.T.Wateril). Longitudinal ACQ penetration was extremely shallow in L. confertus and only slightly better in E. cloeziana. Longitudinal penetration was good in both E. obliqua and E. pellita, although there was some variation in treatment results with length of pressure period. The results suggest that through-boring might be a reasonable approach for achieving heartwood penetration in some Eucalyptus species, although further studies are required to assess additional treatment schedules and to determine the effects of the process oil flexural properties of the poles.

Evaluation of wood characteristics of tropical post-mid rotation plantation Eucalyptus cloeziana and E. pellita: Part (d) Veneer and plywood potential.

Logs from two hardwood plantations in north Queensland were peeled to assess the veneer and plywood potential of fast-grown tropical plantation eucalypts. After visual grading and veneer recovery calculatios, selected veneers were assembled to produce plywood panels. These were tested for mechanical properties and glue bond strength to determine the suitability of young, fast-grown, tropical eucalytps for panel product applications.

Temperature and water potential relations of tropical Trametes and other wood-decay fungi from the indigenous forests of Zimbabwe

Three isolates each, of nine different Trametes and five other wood inhabiting basidiomycetes, were collected from the indigenous forests of Zimbabwe, and the impact of temperature (20-60 degrees C), osmotic and matric potential (-0.5 to - 8.0 MPa), and their interactions on in vitro growth compared. Generally, there was no significant difference between growth of isolates of the same species in relation to temperature. Temperature relationships of the species studied correlated well with their geographic distributions. Species occurring in hot, dry regions tolerated a wide temperature range, with some showing unusually high thermotolerance (55 degrees, T. socotrana, T. cingulata and T. cervina). There were significant intra-strain differences for individual species in relation to solute potential on glycerol-modified media. Generally, growth of ail species was better on glycerol- and KCl-modified osmotic media than on a metrically-modified medium (PEG 8000) at 25, 30 and 37 degrees. The limits for growth on the osmotic media were significantly wider than matric medium, being - 4.5 to - 5.0 and - 2.5 to - 4.5 MPa, respectively. An Irpex sp. grew at lower water potentials than all other species, with good growth at - 7.0 MPa. This study suggests that the capacity of these fungi for effective growth over a range of temperatures, osmotic and matric potentials contributes to their rapid wood decay capacities in tropical climates.

Characterization of wood biochar and evaluation of its adsorption potential for removal of sulphate from produced water in offshore oil and gas industry

This thesis analyses the potential of wood biochar as an adsorbent in removal of sulphate from produced water. In worldwide offshore oil and gas industry, a large volume of waste water is generated as produced water. Sulphur compounds present in these produced water streams can cause environmental problems, regulatory problems and operational issues. Among the various sulphur removal technologies, the adsorption technique is considered as a suitable method since the design is simple, compact, economical and robust. Biochar has been studied as an adsorbent for removal of contaminants from water in a number of studies due to its low cost, potential availability, and adsorptive characteristics. In this study, biochar produced through fast pyrolysis of bark, hardwood sawdust, and softwood sawdust were characterized through a series of tests and were analysed for adsorbent properties. Treating produced water using biochar sourced from wood waste is a two-fold solution to environmental problems as it reduces the volume of these wastes. Batch adsorption tests were carried out to obtain adsorption capacities of each biochar sample using sodium sulphate solutions. The highest sulphur adsorption capacities obtained for hardwood char, softwood char and bark char were 11.81 mg/g, 9.44 mg/g, and 7.94 mg/g respectively at 10 °C and pH=4. The adsorption process followed the second order kinetic model and the Freundlich isotherm model. Adsorption reaction was thermodynamically favourable and exothermic. The overall analysis concludes that the wood biochar is a feasible, economical, and environmental adsorbent for removal of sulphate from produced water.

An expert model approach to assess the potential of non-wood forest products for forest owners

Mestrado em Engenharia Florestal e dos Recursos Naturais - Instituto Superior de Agronomia - UL