Colombo, Brazil
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Magalhaes W.L.E.,Embrapa Forestry | Cao X.,South China University of Technology | Lucia L.A.,North Carolina State University
Tappi Journal | Year: 2011

Aligned cellulose nanocrystals/cellulose coelectrospun nanofibers were successfully prepared by using a home-built coelectrospinning and collection system. Cellulose I was dissolved in N-methyl morpholine oxide at 120°C and diluted with dimethyl sulfoxide, which was used in the external concentric capillary needle as the sheath (shell) solution. A cellulose nanocrystal suspension obtained by sulfuric acid hydrolysis of cotton fibers was used as the core liquid in the internal concentric capillary needle after transferring from water to dimethyl sulfoxide. The resultant coelectrospun nanocomposite films were collected onto a rotating wire drum and were characterized by field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy, thermogravimetric analysis, and tensile measurements. The FE-SEM image showed that the cellulose nanocrystals did not appear to cluster in the film formed. Although the crystallinity index of nanocomposite fibers was lower than the unreinforced cellulose electrospun fibers, the cellulose type II reinforced with cellulose nanocrystals had a much higher tensile stress (about 140 MPa), almost twofold that of pure cellulose. This latter result indicated that the alignment and adhesion of amorphous cellulose nanofibers played a crucial role on the mechanical properties of electrospun cellulosic fiber mats.


Buch A.C.,Federal University of Paraná | Brown G.G.,Embrapa Forestry | Niva C.C.,Embrapa Forestry | Sautter K.D.,Positivo University | Sousa J.P.,University of Coimbra
Applied Soil Ecology | Year: 2013

The indiscriminate and excessive use of pesticides poses serious risks to humans and the environment, including soil biota. Ecotoxicological tests are useful to indicate the extent to which these chemicals are harmful and how and where their effects occur. Some of these tests were standardized by ISO (International Organization for Standartization) using the earthworm species Eisenia fetida and Eisenia andrei, both native to temperate climates. However, these species may be of lower relevance for soil ecotoxicological studies since they live in the litter and feed on fresh organic matter. The species Pontoscolex corethrurus, native to tropical regions, may be an alternative for more relevant ecotoxicological tests as it is an endogeic geophagous species. However, little is known of its sensitivity to pesticides. Therefore, avoidance and mortality tests were performed using E. andrei and P. corethrurus and three pesticides commonly used in Brazilian agriculture: carbendazim, carbofuran and glyphosate. The tests were conducted in tropical artificial soil (TAS). For carbendazim, the median avoidance concentration (AC50) was 76.1 and 65.8mga.i.kg-1 and the median lethal concentration (LC50) 19.7 and 15.3mga.i.kg-1 for E. andrei and P. corethrurus, respectively. For carbofuran, the AC50 was 9.7 and 7.3mga.i.kg-1 and LC50 13.5 and 9.3mga.i.kg-1 for E. andrei and P. corethrurus, respectively. Concentrations applied in the field of these two pesticides have toxic effects on both species. Glyphosate showed no toxic effects for either species even at the highest concentration tested (47mga.i.kg-1), although they displayed avoidance behavior at this concentration. The sensitivity of P. corethrurus appears to be similar to the standard species for the pesticides evaluated reinforcing the notion that E. andrei is a good test species. Nevertheless, further studies should be undertaken using other contaminants to confirm the similar sensitivity of both species and the relevance of E. andrei in ecotoxicological tests. © 2012 Elsevier B.V.


Bartz M.L.C.,Santa Catarina State University | Pasini A.,State University Londrina | Brown G.G.,Embrapa Forestry
Applied Soil Ecology | Year: 2013

It is well known that earthworm populations tend to increase under no-tillage (NT) practices, but abundances tend to be highly variable. In the present study, data from the literature together with those on earthworm populations sampled in six watersheds in SW Paraná State, Brazil, were used to build a classification of the biological soil quality of NT systems based on earthworm density and species richness. Earthworms were collected in 34 farms with NT aging from 3 to 27 yr, in February 2010, using an adaptation of the TSBF (Tropical Soil Biology and Fertility) Program method (hand sorting of five 20cm×20cm holes to 20cm depth). Six forest sites were also sampled in order to compare abundances and species richness with the NT systems. Species richness in the 34 NT sites and in the 6 forests ranged from 1 to 6 species. Most earthworms encountered were exotics belonging to the genus Dichogaster (D. saliens, D. gracilis, D. bolaui and D. affinis) and native Ocnerodrilidae (mainly Belladrilus sp.), all of small individual size. In a few sites, individuals of the Glossoscolecidae (P. corethrurus, Glossoscolex sp., Fimoscolex sp.) and Megascolecidae (Amynthas gracilis) families were also encountered, in low densities. Urobenus brasiliensis (Glossoscolecidae) were found only in the forest fragments. In the NT farms, earthworm abundance ranged from 5 to 605 indm-2 and in the forest sites, from 10 to 285indm-2. The ranking of the NT soil biological quality, based on earthworm abundance and species richness was: poor, with <25 individuals per m-2 and 1 sp.; moderate, with ≥25-100 individuals per m-2 and 2-3 sp.; good, with >100-200 individuals per m-2 and 4-5 sp.; excellent, with >200 individuals per m-2 and >6 sp. About 60% of the 34 farms fell into the poor to moderate categories based on this classification, so further improvements to the NT farm's management system are needed to enhance earthworm populations. Nevertheless, further validation of this ranking system is necessary to allow for its wider-spread use. © 2013 Elsevier B.V.


Mattos B.D.,Federal University of Pelotas | de Cademartori P.H.G.,Federal University of Paraná | Lourencon T.V.,Federal University of Pelotas | Gatto D.A.,Federal University of Pelotas | Magalhaes W.L.E.,Embrapa Forestry
International Biodeterioration and Biodegradation | Year: 2014

This study aimed to evaluate changes in the chemical composition and mechanical properties of static bending of wood from two fast-growing eucalypt species (blue gum and lemon-scented gum) after exposure for one year in a field test. To achieve this, decayed untreated wood (after 1yr of exposure in the field test) was characterised by chemical analysis, thermogravimetric analysis, and infrared spectroscopy, and was compared with control samples. Mass loss and modulus of elasticity (MOE) and modulus of rupture (MOR) as a function of the exposure time were evaluated. The main findings showed that lignin and carbohydrate content of the two decayed woods decreased after exposure in the field test. Mass loss increased with increasing time of exposure, while MOE and MOR decreased for both woods. Nevertheless, blue gum wood was more susceptible to decay. © 2014 Elsevier Ltd.


Mattos B.D.,Federal University of Pelotas | Misso A.L.,Federal University of Santa Maria | De Cademartori P.H.G.,Federal University of Paraná | De Lima E.A.,Embrapa Forestry | And 3 more authors.
Construction and Building Materials | Year: 2014

This study presents the preparation of polypropylene composites filled with mixtures of household waste of mate-tea and eucalypt particles and aims to increase the economic value chain of mate-tea. Filler mixtures in proportions ranging from 0% to 60% with a fixed PP matrix at 40% were prepared in order to evaluate only the effect of the filler on thermochemical, physical and mechanical properties and on the morphology. The main findings showed that the addition of filler from natural sources decreased thermal stability of composites, but that the temperature of crystallisation increased. Composites with a higher proportion of wood particles showed higher hydrophobic character; however, only the composites with 60% and 54% of mate-tea waste particles showed significantly higher results for water absorption. The use of eucalypt particles increased more mechanical properties than that of household waste, which proves its efficiency as filler. Nevertheless, the use of household waste also increased the properties of the final product and showed that it can be a good alternative for the use of renewable materials in the production of polymeric composites. © 2014 Elsevier Ltd. All rights reserved.


Buch A.C.,Federal University of Paraná | Brown G.G.,Embrapa Forestry | Niva C.C.,Embrapa Forestry | Sautter K.D.,Positivo University | Lourencato L.F.,Federal University of Paraná
Pedobiologia | Year: 2011

Pontoscolex corethrurus (Müller) is a widespread, peregrine earthworm species of the Glossoscolecidae family, native to the Neotropics. This endogeic earthworm shows wide tolerance to environmental variations, being found in many different habitats and soil types throughout the tropics and sub-tropics. To evaluate the life cycle of this species in tropical artificial soil (TAS), a substrate used in ecotoxicological tests, and the influence of food availability and humidity on its growth, earthworms were incubated individually under laboratory conditions. The life cycle was evaluated in four treatments with 24 earthworms (replicates) each: TAS (120. g) without additional food (TAS0), TAS with 5. g of horse manure (TAS5), TAS with 10. g of manure (TAS10) and TAS with 25% greater soil moisture with 5. g of manure (TAS5H). Food was provided every 14. d and the containers maintained at room temperature (20. ±4°C). Cocoons collected in the field were placed individually in the different treatments and the hatching date, growth, development, and reproduction followed for 50 weeks after hatching. New cocoons hatched at 34. d, adulthood was reached at 8 months, and cocoon deposition began 3 months later, so that its life cycle was completed in 12 months. By the 13th week all juveniles in TAS0 had died due to insufficient food resources, while in the other treatments, all the animals had matured by 44 weeks, with significantly higher biomass and length in TAS10 (0.72. g, 5.4. cm), compared with TAS5 and TAS5H (0.59-0.61. g, 5.1-5.4. cm). Growth and weight gain were positively related to food availability, and no negative effect of excess moisture was observed on their growth. With additional food TAS showed no limitations for the development of the species, and it can be used for ecotoxicological tests involving acute toxicity (mortality) and avoidance, although its potential use in chronic tests (reproduction) is more limited. The length of its life cycle and other biological characteristics associated with this parthenogenetic species create some challenges that must be dealt with before this species can be recommended for wider use as a standard ecotoxicological test species. © 2011 Elsevier GmbH.


Duarte A.P.,Federal University of Paraná | Melo V.F.,Federal University of Paraná | Brown G.G.,Embrapa Forestry | Pauletti V.,Federal University of Paraná
Biology and Fertility of Soils | Year: 2014

The survival and cast production of the tropical endogeic earthworm Pontoscolex corethrurus and the changes in chemical and physical characteristics induced by gut passage were studied over an 80-day period in soils contaminated with different levels of Pb. The soils were from a Pb mining area in the state of Paraná, SE Brazil, and ranged from clayey to sandy texture and total Pb contents from 52 to 9,716 mg kg-1. In soils with the highest total Pb contents, earthworms showed lower survival rates, reduced biomass, high Pb uptake, and negligible cast production. In soils with low to intermediate total Pb (maximum 4,278 mg kg-1), earthworm survival and cast production were higher, biomass loss was lower, and gut passage increased pH, CEC, P, K+, and Mg2+ concentrations in the casts compared to the control soil. In the sandy soil (clay <176 g kg-1), worms preferentially ingested finer soil particles, increasing organic C and silt contents in casts. However, this selective feeding also resulted in higher Pb accumulation in worm tissues. Gut passage also increased water-dispersible clay and reduced flocculation in the casts, increasing the susceptibility of the soil to erosion. Lead contamination and uptake into the tissues did not limit the ability of earthworms to select finer soil particles and to transform soil chemical and physical properties, although it affected cast production rates and survival (especially at high Pb concentrations). © 2014 Springer-Verlag Berlin Heidelberg.


Magalhaes W.L.E.,Embrapa Forestry | Magalhaes W.L.E.,State University of Ponta Grossa | Mattos B.D.,Federal University of Pelotas | Missio A.L.,Federal University of Santa Maria
International Biodeterioration and Biodegradation | Year: 2012

Field tests were used to evaluate the durability of fenceposts treated with 6.5 kg of chromated copper arsenate (CCA) per m 3 of wood. Decay was assessed by qualitative visual analysis and by changes in the chemical structure of the wood. Leaching of CCA from treated fencepost was evaluated by atomic absorption spectroscopy. Moreover, extractives and the acid insoluble lignin were quantified. Treated wood was in perfect condition after 6 yr, in contrast to the untreated wood. Percentages of extractives and lignin increased in the untreated decayed wood. Cr and Cu both migrated from wood to soil, but the concentrations were below those allowed by local environmental law. © 2012 Elsevier Ltd.


Magalhaes W.L.E.,Embrapa Forestry | Pianaro S.A.,State University of Ponta Grossa | Granado C.J.F.,State University of Ponta Grossa | Satyanarayana K.G.,BMS College of Engineering
Journal of Applied Polymer Science | Year: 2013

This article presents preparation of heart-of-peach palm sheath (20-40 wt %) incorporated polypropylene (PP) composites using a single screw extruder. This study is aimed at the waste disposal problem, a societal concern considering that the peach palm cultivation being an important economic activity of some countries, which generate five times more waste than actual heart-of-palm itself. Both the raw materials and their composites were characterized for specific gravity, compressive and impact strengths, softening temperature, and hardness. It was observed that with increasing filler content the compressive and impact strengths of composites continuously decreased, while specific gravity, vicat softening temperature, and hardness showed the opposite trend. However, the optimum mechanical properties were attained for 30 wt % filler, which was the same filler content at which the highest PP crystallinity index was observed. Results also indicate that the lignocellulosic residue induce beta phase on the PP matrix and decrease thermal stability of the composite. Copyright © 2012 Wiley Periodicals, Inc.


Maia C.M.B.F.,Embrapa Forestry | Novotny E.H.,Embrapa Soils | Rittl T.F.,Wageningen University | Hayes M.H.B.,University of Limerick
Current Organic Chemistry | Year: 2013

Soil organic matter (SOM) holds a prominent place among the many indicators that are studied in relation to soil function. Different viewpoints are reflected in characterizing SOM, depending on the study procedures used, or the focus of the researchers. There are many possibilities for the isolation and fractionation of SOM and this has led to a plurality of interpretations and conclusions. Transformations to organic materials that lead to the more recalcitrant components of SOM are outlined, and the associations which these materials can have in the soil environment, and aspects of their compositions are referred to. A review is given of the organic matter pools in soils, of their functions, and of the controls which they have in soil systems. A succinct review is given of physical fractionation procedures for SOM. This approach is highly relevant, though rarely used in modern studies of SOM. The merits and demerits of wet oxidation procedures, relative to dry combustion for determining soil organic carbon contents are discussed, and reference is made to the emerging chemometric techniques based on the use of Near (NIR) and Mid (MIR) infrared spectroscopy. © 2013 Bentham Science Publishers.

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