Sugarcane bagasse cellulose/HDPE composites obtained by extrusion

Natural fibers used in this study were both pre-treated and modified residues from sugarcane bagasse. Polymer of high density polyethylene (HDPE) was employed as matrix in to composites, which were produced by mixing high density polyethylene with cellulose (10%) and Cell/ZrO₂·nH₂O (10%), using an extruder and hydraulic press. Tensile tests showed that the Cell/ZrO₂·nH₂O (10%)/HDPE composites present better tensile strength than cellulose (10%)/HDPE composites. Cellulose agglomerations were responsible for poor adhesion between fiber and matrix in cellulose (10%)/HDPE composites. HDPE/natural fibers composites showed also lower tensile strength in comparison to the polymer. The increase in Young’s modulus is associated to fibers reinforcement. SEM analysis showed that the cellulose fibers insertion in the matrix caused an increase of defects, which were reduced when modified cellulose fibers were used.     

Clinorotation Effect on Response of Cress Leaves to Red and Far-Red Light

Responses of cress (Lepidium sativum L.) seedling leaves to separate and simultaneous illumination with red (660 nm) and far-red (735 nm) light were studied under fast clinorotation (50 rpm) and usual gravity (1g) conditions. The monochromatic light emitting diodes (LEDs) have been used for illumination of seedlings from above. The growth and spatial orientation of leaves and the location of presumable gravisensors in petioles were analysed. Clinorotation in the dark promoted the radial expansion of leaf lamina and unfolding of leaves. It was shown that clinorotation in red light inhibited significantly the elongation of petioles as compared with that under the action of gravity force. Simultaneous red and far-red illumination promoted the growth of petioles under clinorotation, but did not affect the orientation of laminas, which remained the same as of the 1-g control ones. Red light, applied separately and simultaneously with far-red light, guided the bending of laminas as well as the unfolding of leaf petioles in both usual and clinorotation conditions. Histological and cytological analyses of petioles revealed the presence of movable amyloplasts in endodermic cells in proximal region of petioles. Comparison of intracellular positioning of amyloplasts in petioles of leaves grown under clinorotation and the action of gravity allows a presumption that these plastids may be identified as gravisensors of garden cress leaves. The obtained data imply that clinorotation and exposition to monochromatic red light or simultaneous illumination by red and far-red light affect the elongation of petioles of cress seedling leaves. Spectral components guide the unfolding of laminas in a gravity-independent manner.     

Analysis of Brazilian SHP policy and its regulation scenario

This article presents the main regulatory changes that occurred in the Brazilian power sector in 2009, along with the impacts these changes caused on the market, especially related to small hydropower (<30 MW). This study addresses regulatory issues based on inventory studies and records of basic projects, changes related to the compensation of the assured energy of SHPs in the Brazilian energy reallocation market, the socio-economic impact resulting from the construction of SHPs, SHPs in alternative resource auctions and finally the general outlook for the growth scenario for SHPs in Brazil according to the ten-year plan (2010–2019). The overall conclusions of this investigation were that the 2008/2009 biennium was a period of great changes in the regulation of small hydropower plants in Brazil, and the SHP market has shown maturity. Additionally, despite SHP being a type of technology that is completely dominated by domestic industry, in recent years, they have experienced policy disincentives caused by changes to rules that inhibit their growth.     

Seasonal variations in total fatty acid composition of muscles and eye sockets of tucunaré (Cichla sp.) from the Brazilian Amazon area

Seasonal variations in total fatty acid compositions of tucunaré, Cichla sp. in the Janauacá Lake of the Amazon basin were determined by GC. Saturated fatty acids (SFAs) were found to be at higher concentrations than monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) in two seasonal periods. Major fatty acids were palmitic (16:0, 48.5–51.6% of total SFA), oleic (18:1ω9, 43.9–50.2% of total MUFA), docosahexaenoic (DHA, 22:6ω3, 13.5–27.9% of total PUFA) and arachidonic acid (AA, 20:4ω6, 16.0–19.6% of total PUFA). Polyunsaturated fatty acids were the most abundant in muscle during the flood period, and more especially fatty acids 22:6ω3 (10%) and 20:4ω6 (7%). There were no significant variations amongst total lipid SFA, MUFA, and PUFA from eye sockets. The ω6 fatty acid percentages were always higher than the ω3 fatty acid percentages in tucunaré, with ω6/ω3 ratios varying between 1.02 and 1.6 in the flood and drought periods.     

Nicotine dependence subtypes among adolescent smokers: Examining the occurrence, development and validity of distinct symptom profiles.

To increase understanding of the etiology and epidemiology of nicotine dependence among adolescent smokers, the present study examined the occurrence and development of distinct nicotine dependence symptom profiles in a sample of adolescent smokers. A total of 25 secondary schools throughout the Netherlands participated in a 1-year longitudinal study. Multiple dimensions of nicotine dependence were assessed, at two time points, among 641 adolescents (aged 14–17 years) who were classified as smokers. Results showed 4 distinct, yet stable, nicotine dependence subtypes that could be characterized by quantitative as well as qualitative differences. The symptom profiles were similar for males and females but differentially associated with previously identified correlates of nicotine dependence, namely parental smoking, peer smoking, and depressive mood. Finally, differential links of the 4 subtypes were found with regard to smoking uptake and cessation. The finding of qualitative different subgroups of adolescent smokers may have important implications for intervention efforts regarding nicotine dependence and smoking cessation. Such efforts may need to be tailored to the specific subgroups’ needs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optimisation of a continuous flash fermentation for butanol production using the response surface methodology

Factorial design and response surface techniques were used in combination with mathematical modelling and computational simulation to optimise an innovative industrial bioprocess, the production of biobutanol employing the flash fermentation technology. A parametric analysis performed by means of a full factorial design at two levels determined the influence of operating variables on butanol yield and productivity. A second set of simulations were carried out based on the central composite rotatable design. This procedure generated simplified statistical models that describe butanol yield and productivity as functions of the significant operating variables. From these models, response surfaces were obtained and used to optimise the process. For a range of substrate concentration from 130 to 180 g/l, the optimum operating ranges ensure butanol productivity between 7.0 and 8.0 g/l h, butanol yield between 19 and 22%, substrate conversion above 90% and final butanol concentration around 25 g/l.     

A comparative Raman spectroelectrochemical study of selected polyaniline derivatives in a pH-neutral solution

Selected conducting polymers (polyaniline and poly-N-methylaniline), and copolymers of aniline with o-, m-, and p-phenylenediamines, as well as with metanilic acid, have been electropolymerized at a gold electrode, and studied with Raman spectroscopy (532 nm excitation) in a pH-neutral solution. Characteristic Raman features have been obtained and analysed for (co)polymers within electrode potential range of ?0.4 to 0.2 V vs. Ag/AgCl. Changes in Raman spectra depending on electrode potential have been analysed and assigned to different redox forms of (co)polymers. It has been shown that both oxidised and reduced forms of (co)polymers can exist, depending on electrode potential, even in a pH-neutral solution, where most of the polymers studied show no clearly defined electrochemical redox processes.     

Measurements of the refractive index of yttrium in the 50-1300-eV energy region

The first experimental results to our knowledge on the refractive index n = 1 - delta + ibeta of yttrium in the extreme-ultraviolet and soft x-ray energy ranges are discussed. To determine the absorptive part beta, transmittance measurements were performed on pure yttrium films in the 50-1300-eV energy region at beamline 6.3.2 of the Advanced Light Source. The dispersive part delta was then calculated from the absorption results by means of the Kramers-Kronig transformation. Compared with prior tabulated values, the new wet of data for the refractive index of yttrium is in better agreement with the sum rules and contains previously unresolved fine structure information in the regions of the M2,3 and M4,5 absorption edges, where yttrium-based multilayer mirrors operate.