ABSTRACT This work aimed to analyze the influence of treatment pressure on the interaction between stearic acid and an Argon-Oxygen plasma. The fixed variables were the applied RF plasma power (50 W), treatment time (30 min), and treatment starting temperature (273 K). The pressure was varied as follows: 0.2, 0.6, and 1.0 Torr. For all treatment conditions, the etching of the samples was observed, as evidenced by the mass loss of the specimens and by following the gaseous by-products of reactions employing a mass spectrometer coupled to the reaction chamber. Optical emission spectroscopy followed the emission lines of oxygen active species. Functionalization of the specimens was also observed, as shown by the results obtained by Fourier-transform infrared spectroscopy (FTIR) and through XRD analysis. A liquid phase was formed for samples treated at 0.6 and 1.0 Torr, which favored the functionalization process and broadened the band present in the region from 1750 to 1700 cm–1, resulting in amorphous phases. An increase in the intensity of the characteristic peaks of esters was also observed. It can be concluded that the higher pressure favors the formation of a liquid phase and reaction kinetics, resulting in higher functionalization and lower etching. ArgonOxygen Argon Oxygen 50 (5 W, W , W) 30 (3 min, min min) 273 (27 K. K . K) follows 02 0 2 0.2 06 6 10 1 1. Torr conditions observed byproducts products chamber species Fouriertransform Fourier transform FTIR (FTIR analysis 0. 175 170 cm1 cm cm–1 phases kinetics 5 ( 3 27 (2 17 cm–

ABSTRACT Surface treatments such as heat treatments, paints, plasma treatments and galvanizing are important in metal working industry. In those treatments, the required adhesion characteristics can be limited if contaminants are present, so there is a need to clean these surfaces. Conventional processes can be costly, some generated waste may be environmentally hazardous and, in some cases, due to part geometry, they are not effective. Alternatively, plasma treatments which are considered to be environmentally clean, more efficient and with lower operating costs can overcome those difficulties. Due to the reactional complexity of these treatments, there are many fields to be researched, such as which reactions are due to impacts of (neutral) chemical species and which are due to excited species and radiation. The present work aims to verify the interactions between Ar-10%O2 plasma using amino acid L-proline in an inductively coupled radiofrequency plasma. This study showed that oxidative plasma promotes high degradation of the sample. A gas analyzer (quadrupole mass spectrometer) coupled to the gas outlet was used and many gaseous products are detected during treatment, such: H2, H2O, CO, NO (Nitric Oxide) and CO2 while L-proline undergoes intense degradation. The conclusions allow to state that the interaction between the Ar/O2 plasma and L-proline promotes intense degradation through the breakdown of the heterocyclic ring of the molecule.

Abstract In the present work, the influence of the pulse voltage and pressure on the treatment glow discharge characteristics and consequently on the surface properties obtained for low temperature plasma carburized AISI 420 martensitic stainless steel was investigated. Two distinct sets of samples were carburized at 450 °C, for 8 h, one aiming to study the applied pulse voltage effects, which was varied for 500, 600 and 700 V, at a fixed pressure of 400 Pa, and the other aiming to study the pressure effects, which was varied for 200, 400, and 800 Pa, at a fixed pulse voltage of 700 V. Treated samples were characterized by means of confocal laser scanning microscopy (CLSM), X-ray diffraction (XRD) analysis, microhardness and roughness measurements. The glow discharge (plasma) was characterized by optical emission spectroscopy (OES) and current measurements. Results show that the edge effect, surface roughness, hardness and outer layer growth kinetics are dependent on the studied plasma parameters. OES analyses showed that the pulse voltage parameter does not promote significant changes on the plasma chemistry, but confirmed that the molecular H2 gas dissociation rate tends to be significantly affected by the pressure parameter giving important support for the results obtained here.

The aim of this work was to study the influence of varying nitrogen potential during plasma nitriding of stainless steel ISO 5832-1. The control of nitrogen potential was achieved by pulsing the nitrogen flow for different times (01/19, 02/18, and 05/15), where the numbers represent the time (in minutes) of nitrogen flow on/off, thus creating an intermittent flow of nitrogen during the treatment. For all tested conditions - continuous and pulsed flow of nitrogen - the treatment temperature was kept at 425ºC during 2 and 8 hours. Specimens were characterized by means of X-ray diffraction, scanning electron microscopy, optical microscopy, energy-dispersive X-ray spectroscopy, and nanohardness. Results showed that the layer thickness increases with the increase of total treatment time, and decreased for shorter times of pulsed nitrogen flow. Smaller expansion of the austenite phase, as well as less precipitation of chromium nitrides, were also observed for shorter times of pulsed nitrogen flow. Hence, the use of intermittent nitrogen flow appears to be an efficient approach in order to control the nitrogen concentration within the layer, reducing its brittleness.

RESUMO Corpos de prova de aço inoxidável austenítico ISO 5832-1(similar ao AISI 316L, para aplicações biomédicas) apresentando camada superficial enrriquecida em nitrogênio (fase S), obtidos pelos processos de nitretação por plasma em baixa temperatura e SHTPN (Solution Heat Treatment after Plasma Nitriding -Tratamento de solubilização após nitretação por plasma), além de amostras não tratadas, foram testadas em ensaio de desgaste microabrasivo do tipo esfera livre. Os resultados mostraram que as superfícies nitretadas por plasma em baixa temperatura apresentam o menor coeficiente de desgaste para menores tempos de ensaio. No entanto, devido à pequena espessura de camada nitretada, com o aumento do tempo de ensaio as amostras processadas via SHTPN passam a apresentar desempenho superior, indicando que, dependendo das solicitações de desgaste, um ou outro processo apresenta o melhor desempenho.

ABSTRACT Samples of the ISO 5832-1 austenitic stainless steel (similar to AISI 316L for biomedical applications) with nitrogen-rich surface layer (S-phase), obtained by plasma nitriding at low temperature and SHTPN (Solution Heat Treatment after Plasma Nitriding) processes, as well as non-treated samples, were tested to evaluate its micro-abrasive wear behavior. The micro-abrasive wear test were performed using the free-ball configuration. The results pointed out that the nitrided surfaces present lower wear coeficient for short measuring time. Nevertheless, since nitrided layers are relatively thin, for prolongated wear tests the SHTPN samples presented lower wear cofiecient, indicating that depending on the apllication one of the processes will present the best behaviour.

ABSTRACT Studies of the successive application of manure as fertilizer and its combined effect with long-term soil management systems are important to the identification of the interdependence of physical attributes. The aim of this study was to evaluate changes in the physical properties of a Rhodic Kandiudox under management systems employing successive applications of pig slurry and poultry litter, and select physical indicators that distinguish these systems using canonical discriminant analysis (CDA). The systems consisting of treatments including land use, management and the application time of organic fertilizers are described as follows: silage maize under no-tillage (NT-M7 years); silage maize under conventional tillage (CT-M20 years); annual pasture with chisel plowing (CP-P3 years); annual pasture with chisel plowing (CP-P15 years); perennial pasture without tillage (NT-PP20 years); and no-tillage yerba mate (NT-YM20 years) and were compared with native forest (NF) and native pasture (NP). Soil samples were collected from the layers at the following depths: 0.0-0.05, 0.05-0.10, and 0.10-0.20 m, and were analyzed for bulk density, porosity, aggregation, flocculation, penetration resistance, water availability and total clay content. Canonical discriminant analysis was an important tool in the study of physical indicators of soil quality. Organic fertilization, along with soil management, influences soil structure and its porosity. Total porosity was the most important physical property in the distinction of areas with management systems and application times of manure for the 0.0-0.05 and 0.10-0.20 m layers. Soil aeration and micropores differentiated areas in the 0.05-0.10 m layer. Animal trampling and machinery traffic were the main factors inducing compaction of this clayey soil.

ABSTRACT Changes in land use management in agricultural areas can affect the biodiversity of spider families. This study aimed to evaluate spider diversity in different land use systems with capture by two sampling methods, and to identify soil properties that can modulate the occurrence of spiders. Five land use systems, representative of traditional agricultural areas, were evaluated in the west of Santa Catarina, Brazil, to establish a scale of land use intensity: native forest, eucalyptus reforestation areas, pastures, crop-livestock integration areas, and annual crops under no-tillage. The collection methods were manual from soil monoliths and soil traps. Altogether 479 individuals were captured, which were distributed among 20 families, 40 genera, and 8 species. Principal component analysis separated the land use systems and showed an association of spider families with land use in the two sampling methods. There was reduction in spider diversity as the intensity of land use increased. The manual collection method was more efficient for families of soil spiders, whereas traps were more efficient for epigeic spiders. The Lycosidae family was more resistant to environmental pressures, while Oonopidae and Amaurobiidae were more sensitive to environmental modifications. The differences in the spider communities were explained by the following soil properties: organic matter, mean weight-diameter of soil aggregates, and resistance to penetration, which were associated with the degree of anthropic intervention in the land use systems.

The reactions that can occur on organic materials treated in plasma enviorement are strongly affected by surface temperature, thus the sharp determination of this variable is extremely important to process control. In situ temperature measurements are often employed; however, the measured point is generally under the treated surface. If in metallic materials the high thermal conductivity minimizes this problem, in non-metallic materials processing it becomes important, because its thermal resistivity besides a high sensibility to small temperature variations. The present work uses a simulation tool to extract thermal data on Ar+O2 RF plasma processing of Stearic Acid. Experimental data were obtained by thermocouples placed inside the samples. The extrapolation of surface temperature was performed by numerical simulation with Autodesk CFD software v.15.1. Results show that the temperature of the surface reaches values higher than the ones measured inside the sample holder. This difference of temperature is in good agreement with the visual observation of the phase transformations in the treated material, showing a simple and valuable tool to better control of plasma treatments.

ABSTRACT Plasma surface cleaning is an alternative process that aims at the fully removal of organic contaminants on several kinds of materials. Despite its advantages, there are still lacks on the comprehension of the complex relations between plasma-generated species and organic molecules during plasma cleaning. In the present work, a linear alkane (hexatriacontane - C36H74), used as a contaminant model, was exposed to an Argon radiofrequency (RF) inductively coupled plasma (ICP). The by-products from degradation were monitored by optical emission spectroscopy (OES) and residual gas analysis (RGA), to identify the influence of sample positioning on E and H discharge modes regions. The exposition to H-mode discharge resulted in more intense and profuse emissions of C-H and C2 systems. RGA results show similar byproducts from degradation in both modes; however, the intensity from treatment in H-mode is largely greater. It was also observed that plasma etching in H-mode is enough to melt the sample, while E-type discharge leaves the surface of the sample apparently unchanged.

RESUMO: Aplicações sucessivas de dejeto líquido de suínos e cama de aviário podem melhorar a estrutura do solo conforme as condições de uso do solo e quantidades adicionadas. Neste estudo, avaliou-se o efeito da aplicação desses fertilizantes sobre os atributos físicos e teores de carbono orgânico de um Nitossolo Vermelho. Os tratamentos contemplam sistemas de uso e manejo do solo e tempo de aplicação de dejeto líquido de suínos e cama de aviário, a saber: mata nativa (MN), erva mate com 20 anos de aplicação de dejetos animais (EM20), pastagem com 15 anos de aplicação (P15), pastagem com 20 anos de aplicação (PP20), pastagem com 3 anos de aplicação (P3), pastagem sem aplicação (P0), milho com 20 anos de aplicação (M20) e milho com 7 anos de aplicação (M7). As amostras de solo foram coletadas nas camadas 0-5, 5-10 e 10-20cm, nas quais foram analisadas: densidade, porosidade, estabilidade de agregados, grau de floculação, resistência à penetração, água disponível, argila total e os teores de carbono orgânico total e particulado e relação C:N. O carbono orgânico total é sensível ao manejo e não teve relação com a adição de dejetos, exceto na camada de 10-20cm na pastagem de azevém 3 anos. A densidade do solo e a resistência à penetração foram as variáveis que tiveram relação com a adição de dejetos e sistemas de uso e manejo do solo.

ABSTRACT: Successive applications of pig slurry and poultry manure can improve the soil structure, according to the land use conditions and amounts applied. This study evaluated the effect of manure fertilization on the physical properties and organic carbon of a Rhodic Kandiudox. Treatments included land use and management and time of pig slurry and poultry litter application, namely: native forest (NF); yerba mate after 20 years of animal waste application (YM20); pasture after 15 years of application (P15); grassland after 20 years of manuring (PP20); grassland after 3 years of manuring (P3); pasture without application (P0), maize after 20 years of application (M20); and maize after 7 years of application (M7). Soil samples were collected in the 0-5, 5-10 and 10-20cm layers, in which density, porosity, aggregate stability, flocculation, penetration resistance, available water, and total clay content, total and particulate organic carbon, and C:N ratio were analyzed. The total organic carbon is sensitive to management and was not related to waste application, except in the 10-20cm layer of ryegrass pasture after three years of manuring. Reponses to waste application and land use and management systems were observed in the variables soil density and penetration resistance.

ABSTRACT Intensive land use can affect macrofaunal biodiversity, which is a property that can be used as a soil quality indicator. This study evaluated the abundance and diversity of soil macrofauna and its relation to soil chemical and physical properties in five land use systems (LUS) in the eastern region of Santa Catarina. The following LUS were studied: native forest (NF), eucalyptus plantations (EP), perennial pasture (PP), integrated crop-livestock (ICL), and no-tillage cropping (NT). The macrofauna was quantified in 0.25 × 0.25 m monoliths and sampled in the 0.00-0.20 m layer in the summer (Jan/2012) and winter (Jul/2012). For each LUS, nine points were sampled, distributed in a 30 × 30 m sampling grid. After screening the edaphic macrofauna organisms, the individuals were counted and identified at the species level when possible, or in major taxonomic groups. The Shannon diversity indices were calculated and the macrofaunal groups together with the physical and chemical properties were subjected to principal component (PCA) and redundancy analysis (RDA). The abundance and diversity of macrofaunal groups are affected by the LUS. The properties of organic matter, macroporosity, bulk density, cation exchange capacity at pH 7.0, base saturation, potential acidity, and exchangeable Al were related to the abundance of soil macrofaunal groups. The stability and biodiversity of soil macrofauna were highest in the LUS of NF, PP, and EP.

O objetivo desse trabalho foi avaliar o uso de Redes Neurais Artificiais (RNA) na seleção dentro de famílias de cana-de-açúcar. O melhor modelo de RNA não apresentou erro, sendo capaz de classificar corretamente todos os genótipos, ou seja, a rede tomou a mesma decisão de seleção realizada pelo melhorista durante a aplicação do BLUP individual simulado (BLUPIS), demonstrando a capacidade de aprendizado da RNA a partir das entradas e saídas informadas nas fases de treinamento e validação. Tendo em vista que a seleção via RNA facilita a identificação dos melhores indivíduos e visando desenvolver uma nova estratégia de seleção dentro das melhores famílias, de forma a garantir que os melhores genótipos da população sejam avaliados nas próximas fases do programa de melhoramento, recomendamos, ranquear as famílias via BLUP, selecionar as melhores e realizar a seleção individual via RNA, a partir das informações coletadas em nível individual nas melhores famílias.

The objective of this study was to evaluate Artificial Neural Networks (ANN) applied in an selection process within sugarcane families. The best ANN model produced no mistake, but was able to classify all genotypes correctly, i.e., the network made the same selective choice as the breeder during the simulation individual best linear unbiased predictor (BLUPIS), demonstrating the ability of the ANN to learn from the inputs and outputs provided in the training and validation phases. Since the ANN-based selection facilitates the identification of the best plants and the development of a new selection strategy in the best families, to ensure that the best genotypes of the population are evaluated in the following stages of the breeding program, we recommend to rank families by BLUP, followed by selection of the best families and finally, select the seedlings by ANN, from information at the individual level in the best families.

Plasma cleaning is a promising technology in surface treatments, despite technological interest its use is limited because its mechanisms still are not entirely understood. This work aims to evaluate how the applied power of an inductively coupled RF discharge at 13,56 MHz, with Ar and Ar+10%O2 atmospheres, affects its capabilities to etch an organic molecule. Mass variation rate was used as direct characterization of degradation process and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) was performed to search for residual molecular modifications. Additionally, optical emission spectroscopy (OES) measurements were performed to monitor the offer of active species in the gaseous volume. In experimental conditions was possible attain mass reduction from sample, with higher mass loss rate when applied power is increased. Material characterization shows the possibility of attain a high etch rate, while no structural modifications were detected, if the temperature is controlled.

This work reports experimental results on sintered PIM 316L stainless steel low-temperature plasma nitriding. The effect of treatment temperature and time on process kinetics, microstructure and surface characteristics of the nitrided samples were investigated. Nitriding was carried out at temperatures of 350, 380, 410 and 440 ºC , and times of 4, 8 and 16 h, using a gas mixture composed by 60% N2 + 20% H2 + 20% Ar, at a gas flow rate of 5.00 × 10-6 Nm³s-1, and a pressure of 800 Pa. The treated samples were characterized by scanning electron microscopy, X-ray diffractometry and microhardness measurements. Results indicate that low-temperature plasma nitriding is a diffusion controlled process. The calculated activation energy for nitrided layer growth was 111.4 kJmol-1. Apparently precipitation-free layers were produced in this study. It was also observed that the higher the treatment temperature and time the higher is the obtained surface hardness. Hardness up to 1343 HV0.025 was verified for samples nitrided at 440 ºC. Finally, the characterization of the treated surface indicates the formation of cracks, which were observed in regions adjacent to the original pores after the treatment.

O principal objetivo do estudo foi avaliar a presença de infecção por Borrelia burgdorferi em vertebrados domésticos e silvestres e ectoparasitas em áreas endêmicas do estado de Minas Gerais, Brasil. Um total de 445 amostras de soro foram examinadas por ELISA, onde usou-se a cepa americana G39/40 de Borrelia burgdorferi e 3.821 amostras de carrapatos foram testados pela reação em cadeia da polimerase (PCR). Anticorpos anti -B. burgdorferi foram encontrados em 30 amostras de soro (6,74%); três marsupiais (7,69%), três em roedores (2,80%), em nove cães (6,25%) e 15 em cavalos (9,68%). Nested-PCR realizada em amostras de DNA obtidas a partir de carrapatos coletados demonstraram resultados negativos. Apesar das tentativas para amplificar o DNA de B. burgdorferi a partir de carrapatos não tenha sido bem sucedido, a presença de soroatividade em vertebrados sugere a possibilidade de espécies de Borrelia circulando nestas regiões. Mais pesquisas são necessárias para fornecer informações sobre a presença de Borrelia em território brasileiro e sua associação com a Síndrome de Baggio-Yoshinari.

The main of the study was to evaluate the presence of Borrelia burgdorferi infection in domestic and wild vertebrates and ectoparasites in endemic areas from the state of Minas Gerais, Brazil. A total of 445 serum samples were examined by ELISA, which used the Borrelia burgdorferi strain G39/40 U.S. source and 3,821 tick samples were tested by polymerase chain reaction (PCR). B. burgdorferi antibodies were found in 30 serum samples (6.74%); three in marsupials (7.69%), three in rodents (2.80%), nine in dogs (6.25%), and 15 in horses (9.68%). Nested-PCR performed in DNA samples obtained from collected ticks demonstrated negative results. Although attempts to amplify B. burgdorferi DNA from ticks had been not successful, the presence of seroreactive vertebrates suggests the possibility the Borrelia species circulating in these regions. Further research is required to provide information on the presence of Borrelia in Brazilian territory and its association with Baggio-Yoshinari syndrome.