DC Plasma Technology Applied to Powder Metallurgy: an Overview

DC plasma is a very promising technology for processing different materials, and is becoming especially interesting when low environmental impact and high-performance treatments are needed. Some of the intrinsic characteristics of DC plasma technology, which make it suitable for powder metallurgy （PM） and powder injection molding （PIM） parts production, are low- pressure processing and plasma environment high reactivity. Moreover it can be considered as a highly competitive green technology. In this work, an overview of some of the important DC plasma techniques applied to PM and PIM parts processing is presented. Emphasis is given to the descriptions of the main characteristics and the technique potentials of plasma-assisted nitriding, plasma-assisted thermal debinding, plasma-assisted sintering, and simultaneously plasma-assisted sintering and surface alloying. The aspects presented and discussed in this paper indicate that DC plasma processes are promising and competitive techniques for PM and PIM parts processing.

Accessibility and Visibility Analysis of Moinhos de Vento Park in Porto Alegre, Rio Grande do Sul, Brazil

This paper analyzes physical and visual accessibility at Moinhos de Vento Park in Porto Alegre, Rio Grande do Sul, Brazil, through Space Syntax methods. The Park presents a particularity in its configuration： it is crossed by an important avenue in the city that splits it in two portions linked by an elevated pedestrian path. The two portions of the park have different accessibility degrees and intensity of use due to -- we believed -- the way they are inserted in the urban pattern. Both the barrier caused by the avenue crossing the park and the differences of connectedness of each portion to its surrounding grid result in the level of integration occurring in different ways, turning the east portion less intensely used. The all-line and visibility integration maps showed that this was the case, and confirmed that spatial configuration plays an important role in rendering the east portion less integrated and in explaining the more intense use of the west portion. Integration maps showed that the most integrated areas are indeed the most used ones, although line and visibility integration differed slightly as to the exact location. This difference was probably due to the way barriers were modeled, since permeability took into account the paths while visibility considered all the ground as a whole, provided there were no barriers to sight. Another explanation for the difference is the lake located at the center of the west portion which contributed to this location＇s visual integration but, on the other hand, displaced line integration to the larger convex space to the north.

Effect of Thermal Processing, Press Throughput and Roller-Die Gap on Physicochemical Properties of Broiler Feed Pellets

The present study aimed to evaluate the effect of thermal processing, press throughput and roller-die gap on pellet physical quality, protein solubility and starch gelatinization in a corn-soybean based broiler diet. The different processing factors were combined in a 2 × 5 × 3 factorial arrangement with eight randomized block consisting of eight production series： two thermal processing treatments （conditioning-pelleting or conditioning-expanding-pelleting）, five press throughput levels （18, 21, 24, 27 and 30 ton/h） and three roller-die gap （0.50, 0.75 and 1.00 mm）, which resulted in 30 different processed feeds. For determination of pellet durability index （PDI）, amount of intact pellets, degree of starch gelatinization and protein solubility, one composed feed sample was collected per treatment in each of eight production series, totaling eight replicates per treatment. Data concerning the amount of intact pellet and protein solubility in KOH were transformed using a variation of Box-Cox transformation in order to fit a normal distribution （P 〉 0.05）. Pellet physical quality was enhanced by conditioning-expanding treatment （P 〈 0.01）, narrower roller-die-gap （P 〈 0.01） and reduced press throughput （P 〈 0.01）. Protein solubility in KOH was impaired （P 〈 0.01） in the expander treatment and larger roller-die distance （0.75 mm and 1.00 mm） （P 〈 0.01）. Finally, greater starch gelatinization degree was achieved in expanded treatment （P 〈 0.01） and in 1.00 mm roller-die gap （P 〈 0.05）. The factors evaluated in this study resulted in interactions and significant effects on physicochemical properties of broiler feed pellets.

Use of the SPAD-502 in Estimating Nitrogen Content in Leaves and Grape Yield in Grapevines in Soils with Different Texture

The SPAD reading may be used in estimating total nitrogen content (N) in leaves and even in estimating grape yield in grapevines. The objective of this study was to estimate total N content in leaves and grape yield using the SPAD-502 in grapevines submitted to nitrogen fertilization in soils with clayey and sandy texture. In 2008, two experiments were installed in the Southern region of Brazil. In experiment 1, Cabernet Sauvignon grapevines were planted in a soil with clayey texture and with application of 10, 20, 40 and 80 kg·N·ha-1·year-1. In experiment 2, Cabernet Sauvignon grapevines were planted in a soil with sandy texture and with the application of 0, 10, 15, 20, 40, 80 and 120 kg·N·ha-1·year-1. In the grapevines of the two experiments and during the period from 2008 to 2010, SPAD readings were made on leaves throughout the flowering period and at change in color of the berries using the portable chlorophyll meter Minolta-SPAD-502. The leaves were collected, dried, ground and submitted to analysis of the total N content. In addition, grape yield per hectare was evaluated. The SPAD-502 readings estimated the total N content in flowering and at change in color of the berries in the Cabernet Sauvignon grapevines grown on soils with clayey texture and sandy texture, especially in the first year of evaluation. However, the precision of the SPAD-502 readings is low, with there being no relationship between the SPAD-502 readings and grape yield.

Association between obesity and self-reported diseases: Population-based study among adults in southern Brazil

Introduction: There are few population-based studies conducted in Brazil outside the major urban centers, the prevalence of overweight, obesity and associated factors in the up country cities remains not noticed. Particularly, the characteristics of this phenomenon are unknown in the mountain regions of Santa Catarina (state of the southern region), which concentrate the lowest economic and social development of the state, where culture, dietary habits and climate are quite peculiar. Objective: To estimate the prevalence of nutritional status and its association with self-reported diseases in adults of Lages, Santa Catarina. Methods: A cross sectional study including adults was conducted (n = 2022). Demographic information was collected as well as anthropometric measurements, through a number of interviews and physical examinations. The outcome of the study was the body mass index (BMI). The descriptive statistic was performed, as well as simple associations between BMI and the independent variables by sex. Correlations between BMI, abdominal circumference and self-reported diseases for men and women were tested separately. Results: The prevalence of normal weight, overweight and obesity among men was 41%, 39% and 19% respectively. Among women, the prevalence rates were 43%, 31% and 26%. It was observed that the obesity increase is correlated with low levels of education. The greater the BMI the more negative was the self-assessment of health. It was found a positive correlation between BMI and abdominal circumference, with diabetes mellitus and high blood pressure levels. Conclusions: There was a high prevalence of overweight and obesity in Lages, SC. Strategies involving the various sectors of the community should be considered to reverse this process.

Novel Mechanical Interface Design for Automotive Starting Systems

Stop-start vehicles(SSVs)represent a potential alternative for improving internal combustion engine(ICE)efficiency.SSVs provide ICEs with the functionality of turning the engine off during traffic halts and restarting it without intervention by the driver.This strategy reduces fuel consumption,especially in dense urban traffic areas,and contributes to emissions reduction to meet green emissions targets.The most widely adopted SSV system has a mechanical interface to connect the electric starter motor to the ICE,which requires increased robustness compared with standard starting motors.This requirement allows the motor to withstand a higher number of engine start cycles compared with a standard starting motor.Nevertheless,it is a critical problem for wider adoption of SSVs.As SSV systems usually are based on the conventional starting system,its durability and noise remains a critical issue to be addressed by automakers.The typical pinion-ring gear interface uses intermittent gear meshing to form a transient coupling interface.The research reported here presents the development of an innovative mechanical interface for starting systems,called the permanent coupling(PC)-type interface,which reduces noise and increases durability compared with the existing design.The results obtained by a functional prototype of the PC-type mechanical interface confirm the feasibility of the proposed concept.The methodology is based on a product development process integrated with lumped-parameter modeling and virtual simulation aimed at reducing failures during prototype test-ing.The new mechanical interface was proven to be a good candidate for increasing the use of SSVs in the automotive market.

Growth of Variable Aspect Ratio ZnO Nanorods by Solochemical Processing

In this work,variable aspect ratio（length divided by diameter） zinc oxide nanorods were synthesized through a simple solochemical method by reacting a Zn2+precursor with sodium hydroxide at low reaction temperatures.The analysis of the X-ray diffraction data indicated that the samples had hexagonal wurtzite structure and nanometric size crystallites.The transmission electron microscopy（TEM） images of the products prepared at60 and 80 ℃ exhibited rod-like architecture,showing that the reaction temperature did not affect the ZnO morphology.The average aspect ratio of the ZnO nanorods decreased from 3.4 to 2.4 when the reaction temperature was raised from 60 to 80 ℃.The samples presented a blue shift in the excitonic absorption compared to ZnO bulk that increased alongside with reaction temperature.In addition,this research investigated the results obtained by varying the concentration of zinc chloride solution.At the same temperature,it could be verified that when the zinc concentration was increased,the diameter of the ZnO nanorods also slightly increased,and much shorter nanorods were achieved,especially in the reactions performed at 50 and 70 ℃.Finally,the growth mechanism of the ZnO nanostructures was proposed based on the results obtained by changing the zinc precursor concentration and reaction temperature.

Shoshonitic Magmatic Series and the High Ba-Sr Granitoids:A Review with Emphasis on Examples from the Neoproterozoic Dom Feliciano Belt of Southern Brazil and Uruguay

Fractional crystallization of parental magmas of shoshonitic or silica-saturated,ultrapotassic affinity,with variable amount of concurrent crustal assimilation,may result in granitic and syenitic rocks.Typical plutonic members of the shoshonitic series are monzonites and quartz monzonites,whilst syenites and quartz syenites are the dominant plutonic products of the ultrapotassic series.Lamprophyric magmas are commonly found in association with both series and are frequently part of coeval mingling/mixing systems.Ultrapotassic and shoshonitic primary magmas,including lamprophyric ones,are derived from amphibole-phlogopite-bearing mantle sources produced by previous,subduction-related metasomatism.Acidic and intermediate rocks can be derived from such parental magmas,generally through AFC processes.Shoshonitic-like granitoids,which have not clear relation with intermediate or basic shoshonitic rocks,or are produced dominantly by crustal melting,should be named high-Ba-Sr granitoids.This study focuses mainly on Neoproterozoic shoshonitic and silica-saturated ultrapotassic rock associations formed in post-collisional settings from southern Brazil and Uruguay.The source of magmas,their evolution,the role played by crustal contamination in modifying pristine geochemical signatures and their tectonic control are discussed based on elemental and Sr-Nd isotope geochemistry.The main features of plutonic rocks related to the shoshonitic series are their potassic,silica-saturated alkaline character,predominance of monzonitic to syenitic compositions,high Sr and Ba contents,monotonous,light REE-enriched patterns,and moderate HFSE contents.Syntectonic shoshonitic and high Ba-Sr granitoids within shear zones show lower alkali,LREE,HFSE,and Sr contents than those formed away from the main deformation sites.Plutonic rocks related to the extended silica-saturated ultrapotassic series are mostly syenites,alkalifeldspar granites and lamprophyres with K_(2)O/Na_(2)O ratios above 2.The typical values of^(87)Sr/^(86)Sri for shoshonitic plutonic rocks are 0.706–0.708,ranging from 0.704 to 0.710.Theε_(Nd)(t)values are negative and vary from 0 to-24.Crustal contribution tends to increase^(87)Sr/^(86)Sri and decreaseε_(Nd)(t)values,depending on protolith isotope signature,melting conditions and volume of assimilated material.Ultrapotassic rocks,on the other hand,show higher^(87)Sr/^(86)Sri ratios,from 0.709–0.711 up to 0.720.Geochemical evidence,including Sr-Nd isotope data,indicates that the shoshonitic and ultrapotassic rocks discussed in this study were formed from OIB-like sources with strong influence of previous subduction,probably a phlogopite,K-amphibole bearing veined mantle.Lithological variability in ultrapotassic-shoshonitic associations is interpreted to result from(i)variation of source composition,(ii)different melt fractions from similar sources,(iii)mixing-mingling,fractional crystallization,and assimilation processes.