Improved moisture and hydrocarbons barrier of epoxy resin-based coating

To improve the surface characteristics of epoxy resin coatings, a treatment by fluorine-containing plasma was used to develop a coating with low surface free energy and improved chemical resistance. Through the coating analysis it was possible to verify information about the CF(n) bond formation and the fluorination depth. The best plasma process parameters presented the best fluorination depth, 90 nm, and fluorine concentration was nearly 30%. The improvement in contact angle of water was 50% and of raw petroleum was 130%. Salt spray test proves that the coating fluorination decreases the chance of substrate corrosion.

Valve friction and nonlinear process model closed-loop identification

Among several process variability sources, valve friction and inadequate controller tuning are supposed to be two of the most prevalent. Friction quantification methods can be applied to the development of model-based compensators or to diagnose valves that need repair, whereas accurate process models can be used in controller retuning. This paper extends existing methods that jointly estimate the friction and process parameters, so that a nonlinear structure is adopted to represent the process model. The developed estimation algorithm is tested with three different data sources: a simulated first order plus dead time process, a hybrid setup (composed of a real valve and a simulated pH neutralization process) and from three industrial datasets corresponding to real control loops. The results demonstrate that the friction is accurately quantified, as well as ""good"" process models are estimated in several situations. Furthermore, when a nonlinear process model is considered, the proposed extension presents significant advantages: (i) greater accuracy for friction quantification and (ii) reasonable estimates of the nonlinear steady-state characteristics of the process. (C) 2010 Elsevier Ltd. All rights reserved.

TL and OSL properties of KAlSi(3)O(8):Mn, obtained by sol-gel process

Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) properties of KAlSi(3)O(8):Mn glasses obtained through the sol gel technique were investigated. Samples were obtained with five different molar concentrations of 0.25, 0.5, 1, 2 and 5 mol% of manganese. Transmission Electronic Microscopy (TEM) indicated the occurrence of nanoparticles composed by glass matrix elements with Mn. Best results for TL response were obtained with 0.5 mol% Mn doped sample, which exhibits a TL peak at 180 degrees C. The TL spectrum of this sample presents a broad emission band from 450 to 700 nm with a peak at 575 nm approximately. The emission band fits very well with the characteristic lines of the Mn(2+) emission features. According to this fact, the band at 410 nm can be ascribed to (6)A(1)(S) -> (4)A(1)(G), (4)E(G) transition, while the 545 nm band can be attributed to the superposition of the transitions (6)A(1)(S) -> (4)T(2)(G) and (6)A(1)(S) -> (4)T(1)(G). The dependence of the TL response with the energy of X-rays (27-41 keV) showed a small decrease of the TL intensity in the high energy region. Excitation with blue LEDs showed OSL in the UV region with a fast decay component. (C) 2011 Elsevier Ltd. All rights reserved.

Surface modification of bovine bone ash prepared by milling and acid washing process

Bovine bone ash is the main raw material for fabrication of bone china, a special kind of porcelain that has visual and mechanical advantages when compared to usual porcelains. The properties of bone china are highly dependent on the characteristics of the bone ash. However, despite a relatively common product, the science behind formulations and accepted fabrication procedures for bone china is not completely understood and deserves attention for future processing optimizations. In this paper, the influence of the preparation steps (firing, milling, and washing of the bones) on the physicochemical properties of bone ash particles was investigated. Bone powders heat-treated at temperatures varying from 700 to 1000 degrees C were washed and milled. The obtained materials were analyzed in terms of particle size distribution, chemical composition, density, specific surface area, FTIR spectroscopy, dynamic electrophoretic mobility, crystalline phases and scanning electron microscopy. The results indicated that bone ash does not significantly change in terms of chemistry and physical features at calcination temperatures above 700 degrees C. After washing in special conditions, one could only observe hydroxyapatite in the diffraction pattern. By FTIR it was observed that carbonate seems to be mainly concentrated on the surface of the powders. Since this compound can influence in the dispersion stability, and consequently in the quality of the final bone china product, and considering optimal washing parameters based on the dynamic electrophoretic mobility results, we describe a procedure for surface cleaning. (c) 2009 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Three-Dimensional Stress Distribution in the Human Periodontal Ligament in Masticatory, Parafunctional, and Trauma Loads: Finite Element Analysis

Background: The presence of the periodontal ligament (PDL) makes it possible to absorb and distribute loads produced during masticatory function and other tooth contacts into the alveolar process via the alveolar bone proper. However, several factors affect the integrity of periodontal structures causing the destruction of the connective matrix and cells, the loss of fibrous attachment, and the resorption of alveolar bone. Methods: The purpose of this study was to evaluate the stress distribution by finite element analysis in a PDL in three-dimensional models of the upper central incisor under three different load conditions: 100 N occlusal loading at 45 degrees (model 1: masticatory load); 500 N at the incisal edge at 45 degrees (model 2: parafunctional habit); and 800 N at the buccal surface at 90 degrees (model 3: trauma case). The models were built from computed tomography scans. Results: The stress distribution was quite different among the models. The most significant values (harmful) of tensile and compressive stresses were observed in models 2 and 3, with similarly distinct patterns of stress distributions along the PDL. Tensile stresses were observed along the internal and external aspects of the PDL, mostly at the cervical and middle thirds. Conclusions: The stress generation in these models may affect the integrity of periodontal structures. A better understanding of the biomechanical behavior of the PDL under physiologic and traumatic loading conditions might enhance the understanding of the biologic reaction of the PDL in health and disease. J Periodontol 2009;80:1859-1867.

OPTIMIZATION OF THE TREATMENT PROCESS FOR RESIDUAL WATER FROM A BEER INDUSTRY

The optimization of the treatment process for residual waters from a brewery operating under the modality of an anaerobic reactor and activated sludge combination was studied in two phases. In the first stage, lasting for six months, the characteristics and parameters of the plant operation were analyzed, wherein a diversion rate of more than 50% to aerobic treatment, the use of two aeration tanks and a high sludge production prevailed. The second stage comprised four months during which the system worked under the proposed operational model, with the aim of improving the treatment: reduction of the diversion rate to 30% and use of only one aeration tank At each stage, TSS, VSS and COD were measured at the entrance and exit of the anaerobic reactor mid the aeration tanks. The results were compared with the corresponding design specifications and the needed conditions were applied to reduce the diversion rate towards the aerobic process through monitoring the volume and concentration of the affluent, while applying the strategic changes in reactor parameters needed to increase its efficiency. A diversion reduction from 53 to 34% was achieved, reducing the sludge discharge generated in the aerobic system from 3670mg TSS/l. with two aeration tanks down to 2947mf TSS/l using one tank keeping the same relation VSS:TSS (0.55) and an efficiency of total removal of 98% in terms of COD.

Anisotropic Etching and Nanoribbon Formation in Single-Layer Graphene

We demonstrate anisotropic etching of single-layer graphene by thermally activated nickel nanoparticles. Using this technique, we obtain sub-10-nm nanoribbons and other graphene nanostructures with edges aligned along a single crystallographic direction. We observe a new catalytic channeling behavior, whereby etched cuts do not intersect, resulting in continuously connected geometries. Raman spectroscopy and electronic measurements show that the quality of the graphene is resilient under the etching conditions, indicating that this method may serve as a powerful technique to produce graphene nanocircuits with well-defined crystallographic edges.

Anodic porous alumina structural characteristics study based on SEM image processing and analysis

The present work reports the porous alumina structures fabrication and their quantitative structural characteristics study based on mathematical morphology analysis by using the SEM images. The algorithm used in this work was implemented in 6.2 MATLAB software. Using the algorithm it was possible to obtain the distribution of maximum, minimum and average radius of the pores in porous alumina structures. Additionally, with the calculus of the area occupied by the pores, it was possible to obtain the porosity of the structures. The quantitative results could be obtained and related to the process fabrication characteristics, showing to be reliable and promising to be used to control the pores formation process. Then, this technique could provide a more accurate determination of pore sizes and pores distribution. (C) 2008 Elsevier Ltd. All rights reserved.

Brassinosteroids interact negatively with jasmonates in the formation of anti-herbivory traits in tomato

Given the susceptibility of tomato plants to pests, the aim of the present study was to understand how hormones are involved in the formation of tomato natural defences against insect herbivory. Tomato hormone mutants, previously introgressed into the same genetic background of reference, were screened for alterations in trichome densities and allelochemical content. Ethylene, gibberellin, and auxin mutants indirectly showed alteration in trichome density, through effects on epidermal cell area. However, brassinosteroids (BRs) and jasmonates (JAs) directly affected trichome density and allelochemical content, and in an opposite fashion. The BR-deficient mutant dpy showed enhanced pubescence, zingiberene biosynthesis, and proteinase inhibitor expression; the opposite was observed for the JA-insensitive jai1-1 mutant. The dpyxjai1-1 double mutant showed that jai1-1 is epistatic to dpy, indicating that BR acts upstream of the JA signalling pathway. Herbivory tests with the poliphagous insect Spodoptera frugiperda and the tomato pest Tuta absoluta clearly confirmed the importance of the JA-BR interaction in defence against herbivory. The study underscores the importance of hormonal interactions on relevant agricultural traits and raises a novel biological mechanism in tomato that may differ from the BR and JA interaction already suggested for Arabidopsis.

Association between decay fungi and subterranean termites in the wood biodeterioration process of Tipuana tipu (Benth.) O. Kuntze trees of Sao Paulo city, SP

In the present paper the process of wood biodeterioration of tipuana trees planted in 7 regions of the city of Sao Paulo, SP was evaluated. On the sidewalks, 1109 trees were analyzed taking into consideration the occurrence and association of the xylophagous organisms (decay fungi and subterranean termites), the wood deterioration and the BHD (breast height diameter). The percentage of wood internal deterioration (%) was obtained by non destructive analysis, using a penetrometer. The results had shown that 75% of the tipuana trees presented BHD superior to 50 cm, characterizing them as adult. Decay fungi in the roots and/or trunk had been observed in 338 trees (30.5%). Subterranean termites of Heterotermes sp. and Coptotermes gestroi species had occurred in 307 trees (27.7%), the latter in high infestation level. The association between the fungi and termites was observed, as well as its relation with the BHD, where a greater value of BHD meant higher wood biodeterioration intensity. For tipuana trees, the BHD was considered an indicative attribute of the internal deterioration intensity, caused by these xylophagous organisms.

Antioxidant enzyme activity in Acidithiobacillus ferrooxidans LR maintained in contact with chalcopyrite

The total protein content and activity of the enzymes glutathione reductase (GR), superoxide dismutase (SOD) and thioredoxin reductase (TrxR) were evaluated in Acidithiobacillus ferrooxidans LR cells maintained in contact with the metal sulfide chalcopyrite for 1 and 10 days. A significant decrease in total protein content was observed in cells maintained for 10 days in the presence of chalcopyrite, suggesting proteolytic breakdown clue to exposure to the metal sulfide. Following 10 clays of contact with chalcopyrite, increases in GR, SOD and TrxR activities were detected, suggesting the formation of reactive oxygen species. After ten clays, there was a fivefold increase in GR activity, of which, isoenzyme IV represented approximately 82% of the total. An increase in Fe-SOD activity following ten days exposure to chalcopyrite was also determined, as measured on non-denaturing polyacrylamide gels. Also, after 10 days. an approximately 31-fold increase was observed for TrxR activity. The presence of oxidative stress when A. ferrooxidans is in the presence of chalcopyrite could have a negative impact on bioleaching. (C) 2010 Elsevier Ltd. All rights reserved.

Metallomics and chemical speciation: towards a better understanding of metal-induced stress in plants

Most metal ions are toxic to plants, even at low concentrations, despite the fact that some are essential for growth and play key roles in metabolism. The majority of metals induce the formation of reactive oxygen species, which require the synthesis of additional antoxidant compounds and enzymes for their removal. New techniques that have greatly improved the identification, localisation and quantification of metals within plant tissues have led to the science of metallomics. This advancement in knowledge should eventually allow the characterisation of plants used in the process of phytoremediation of soils contaminated with toxic metals.

Podzolization as a deferralitization process: dynamics and chemistry of ground and surface waters in an Acrisol-Podzol sequence of the upper Amazon Basin

Hydrochemical processes involved in the development of hydromorphic Podzols are a major concern for the upper Amazon Basin because of the extent of the areas affected by such processes and the large amounts of organic carbon and associated metals exported to the rivers. The dynamics and chemical composition of ground and surface waters were studied along an Acrisol-Podzol sequence lying in an open depression of a plateau. Water levels were monitored along the sequence over a period of 2 years by means of piezometers. Water was sampled in zero-tension lysimeters for groundwater and for surface water in the drainage network of the depression. The pH and concentrations of organic carbon and major elements (Si, Fe and Al) were determined. The contrasted changes reported for concentrations of Si, organic carbon and metals (Fe, Al) mainly reflect the dynamics of the groundwater and the weathering conditions that prevail in the soils. Iron is released by the reductive dissolution of Fe oxides, mostly in the Bg horizons of the upslope Acrisols. It moves laterally under the control of hydraulic gradients and migrates through the iron-depleted Podzols where it is exported to the river network. Aluminium is released from the dissolution of Al-bearing minerals (gibbsite and kaolinite) at the margin of the podzolic area but is immobilized as organo-Al complexes in spodic horizons. In downslope positions, the quick recharge of the groundwater and large release of organic compounds lead to acidification and a loss of metals (mainly Al), previously stored in the Podzols.

Deciphering the weathering processes using environmental mineralogy and geochemistry: Towards an integrated model of laterite and podzol genesis in the Upper Amazon Basin

This article reports major results from collaborative research between France and Brazil on soil and water systems, carried out in the Upper Amazon Basin. It reveals the weathering processes acting in the partly inundated, low elevation plateaus of the Basin, mostly covered by evergreen forest. Our findings are based on geochemical data and mineral spectroscopy that probe the crystal chemistry of Fe and Al in mineral phases (mainly kaolinite, Al- and Fe-(hydr)oxides) of tropical soils (laterites). These techniques reveal crystal alterations in mineral populations of different ages and changes of metal speciation associated with mineral or organic phases. These results provide an integrated model of soil formation and changes (from laterites to podzols) in distinct hydrological compartments of the Amazon landscapes and under altered water regimes. (C) 2010 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.

Tree-ring formation, radial increment periodicity, and phenology of tree species from a seasonal semi-deciduous forest in southeast Brazil

Many tropical tree species produce growth rings in response to seasonal environmental factors that influence the activity of the vascular cambium. We applied the following methods to analyze the annual nature of treering formation of 24 tree species from a seasonal semi-deciduous forest of southeast Brazil: describing wood anatomy and phenology, counting tree rings after cambium markings, and using permanent dendrometer bands. After 7 years of systematic observations and measurements, we found the following: the trees lost their leaves during the dry season and grew new leaves at the end of the same season; trunk increment dynamics corresponded to seasonal changes in precipitation, with higher increment (active period) during the rainy season (October-April) and lower increment (dormant period) during the dry season (May-September); the number of tree rings formed after injuries to the cambium coincided with the number of years since the extraction of the wood samples. As a result of these observations, it was concluded that most study trees formed one growth ring per year. This suggests that tree species from the seasonal semi-deciduous forests of Brazil have an annual cycle of wood formation. Therefore, these trees have potential for use in future studies of tree age and radial growth rates, as well as to infer ecological and regional climatic conditions. These future studies can provide important information for the management and conservation of these endangered forests.