Stability on turning of Inconel 718 using vibration-assisted machining

International audienceInconel is a hard-to-cut material that uses very low cutting speed. In turning operation added to the low cutting velocity, there is also a second limitation to productivity: chatter. In order to reduce chatter, the depth of cut is reduced and the material removal rate is lower. One option to avoid reducing the depth of cut is using vibration assistance machining. This paper presents a numerical investigation using 1D vibrations in the feed direction in order to reduce chatter in turning Inconel 718

Family resources and promotion of development of children with cerebral palsy

Introduction: Cerebral palsy (CP) describes a group of permanent disorders of movement and posture, causing activity limitation, attributed to a non-progressive disorder that occurs in the developing brain. The family of a child with CP becomes essential and will be much in demand, both to drive the child’s development in a favourable environment and to maintain his health. A well-functioning family and a variety of environmental stimuli can be decisive in supporting children with CP.Objective: To analyse family dynamics and the availability of child development-promoting resources in the family environment of children with CP.Methods: We recruited a sample of 25 mothers of children with PC in the Hospital das Clínicas of Ribeirão Preto. Mothers completed the Family Adaptability and Cohesion Evaluation Scale (FACES IV), the Inventory of the Family Environment Resources (FER) and a sociodemographic questionnaire. Results: The average age of mothers was 32.3 (±7.6) years; 68 per cent had completed at least primary education and 80 per cent were living with a partner. The average age of the children was 48.0 (±15.5) months; 56 per cent were girls and 68 per cent attended day care or preschool. Moderate correlations were observed between environmental resources and family functioning (0.39<r<0.70), and the FACES IV indicative scales of good family functioning showed positive correlations with the overall score of FER.Conclusion: Children with PC have few opportunities to participate in activities outside the home, but have received a good supply of resources in their homes. Well-functioning family dynamics showed an association with a greater supply of resources in the domestic environment

MODELING OF FORWARDER PRODUCTIVITY AND COSTS IN THINNED PINE STANDS

AbstractThe aim of this study was to assess the influence of some operational variables on the forwarder productivity and production cost in thinned Pinus taeda L. stands by means of mathematical modeling. This study was carried out in a forest company located at Quedas do Iguaçu, state of Paraná, Brazil. Two stands at 9 and 10 years old from sites with high productivity and similar soil and relief features were studied. A time-motion study was applied to determine the operational cycle time, operational efficiency, productivity, and production costs. By means of mathematical modeling, we verified the influence of the variables: age of stand; cycle time; load volume; and extraction distance on the forwarder productivity and production costs. Models were fitted for estimating the forwarder productivity using cycle time, load volume, and extraction distance. Thus, we obtained the determination adjusted coefficients of 0.88 and 0.94, with an estimate standard error between 6.9% and 13.5%. Models for estimating production cost through the load volume variable presented a determination coefficient of 0.64 and 0.86, with an estimate standard error of 23.1% and 26.7%. Such results have shown the possibility of using mathematical models to estimate the performance of forest machines as a tool for planning the timber harvesting operations

Uma abordagem via CNC para geração de padrões de pontos para análises por CDI

A correlação digital de imagens(CDI) é uma técnica de metrologia óptica capaz de fornecer informações acerca da deformação de superfícies carregadas mecanicamente a partir da análise de imagens digitais desta superfície. Isto se dá por meio da análise comparativa entre imagens digitais tomadas antes e depois do carregamento.Esta técnica requer que um padrão de pontos de distribuição aleatória seja marcado sobre a superfície a ser estudada. Este padrão de pontos fornece uma referência para o procedimento de correlação, permitindo que o CDI obtenha a deformação da superfície com base na deformação do padrão. Diversos estudos recentes afirmam que a qualidade do padrão de pontos utilizados tem direta influência na qualidade dos resultados das análises por CDI.Apesar de muitos estudos numéricos apontarem parâmetros ótimos para os padrões de pontos, a carência de técnicas adequadas para a sua reprodução sobre superfícies impossibilita a sua utilização prática.Diante disto, este trabalho apresenta uma metodologia numérica para geração dos padrões de pontos e também o desenvolvimento de um equipamento de marcação por comando numérico computadorizado capaz de reproduzi-los sobre superfícies reais com precisão.Digital image correlation(DIC) is an optical metrology technique used to acquire deformational and displacement data of mechanically loaded surfaces based on digital images taken before and after the loading. To achieve this, this technique requires the studied surface to have a randomly distributed speckle pattern marked over it. This speckle pattern provides a reference for the image correlation procedure, allowing the DIC system to obtain the surface deformation based on the speckle pattern deformation. In this sense, as already stated in many recent studies, the quality of the used speckle pattern has direct influenceon the quality of the DIC results. Although many numerical studies have already defined near optimum parameters for a speckle pattern, the lack of proper techniques to reproduce it on surfaces rendersit impractical.In sight of this, this work presents anumerical methodology for the generation of speckle patterns and the development of a computadorized numerical control marking equipment capable of accurately reproducing it on real surfaces.La correlación digital de imagen (CDI) es una técnica de metrología óptica capaz de brindarinformaciones acerca de la deformación de superficies cargadas mecánicamente a partir del análisis de imágenes digitales de esa superficie,anteriores y posteriores a la carga. Para eso, esta técnica requiere que un patrón de puntos, de distribución aleatoria, sea diseñado sobre la superficie a ser estudiada. Este patrón de puntos sirve de referencia para el análisis de correlación de imagen, de manera que las informaciones de deformación de la superficie son obtenidas con base en la deformación experimentada por este patrón de puntos después de la aplicación de la carga. De esta forma, como muestran diferentes estudios recientes, la calidad del patrón de puntos utilizados tiene una influencia directa en la calidad de los resultados de los análisis hechos por CDI. A pesar de que muchos estudios numéricos muestran buenos parámetros para los patrones de puntos, la falta de técnicas adecuadas para su reproducción sobre superficies imposibilita su utilización práctica. Con lo anterior, este trabajo presenta una metodología numérica para la generación de los patrones de puntos y también el desarrollo de un equipamientode impresión de puntos por comando numérico computarizado capaz de reproducirlos sobre superficies reales con precisión

Effects of clays on spin-spin relaxation: a route for non-invasive total clay content quantification

Clay minerals are important components of sandstone rocks, due to their significant role on petrophysical properties like porosity and permeability. These minerals have a particular impact on Nuclear Magnetic Resonance measurements since the iron contained on clays generates internal gradients which directly affect the transverse relaxation. Here, we apply a methodology recently developed to a set of 20 sandstones, with varying clay content and mineralogy, in order to estimate the total clay content by using the effect of internal gradients on transverse relaxation. Based on these measurements, we propose a geochemical rock typing from quantities determined by our measurements, namely the total clay content and porosity

Accessibility in Metrô Rio prior to the 2016 Olympic and Paralympic games.

ABSTRACT:The city of Rio de Janeiro, Brazil hosted the 2016 Olympic and Paralympic Games which brought forth an enormous influx of tourists to a large populated city. This study, analyzed accessibility of the Metrô Line 1 of the subway system in preparation for the games. Photo-based research was used to investigate the Metrô Rio services. Findings suggest that the subway system in the city of Rio de Janeiro, is accessible; however, improvement is needed in the areas of communication, through standardization of language used to describe equipment and accommodations, the standardization of signage and equipment, standardization of navigational logic patterns, and predictability of barriers and services for patrons. A tension was also identified between services provided with assistance and services that promote independence for users with disabilities. Results will help transit agencies to consider accessibility features for all patrons.RESUMO:O Rio de Janeiro foi cidade-sede dos Jogos Olímpicos e Paraolímpicos de 2016, evento que gerou um enorme fluxo de turistas em uma cidade bastante populosa. O presente estudo analisou a acessibilidade do Metrô Linha 1 do sistema metrofer­roviário em preparação para os jogos. A investigação utilizou-se do registro fotográ­fico para averiguar os serviços do Metrô Rio. Os resultados sugerem que o sistemade metrô do Rio de Janeiro é acessível; porém, são necessárias melhorias nas áreas de comunicação por meio da padronização da linguagem utilizada para descrever os equipamentos e espaços, da padronização da sinalização e dos equipamentos oferecidos, da uniformização dos modelos de locomoção e do aumento de previsi­bilidade dos obstáculos e dos serviços oferecidos aos usuários. Também foi iden­tificada uma tensão entre os serviços que se apoiam na assistência e serviços que promovem a independência para os usuários portadores de deficiência. Os resulta­dos auxiliarão agências de transporte a considerar características de acessibilidade para todos os usuários

FUEL PROPERTIES OF FOREST RESIDUES RECOVERED FROM FULL EUCALYPTUS TREE HARVESTING IN DIFFERENT CHIP PRODUCTION SCENARIOS

This study aims to evaluate the fuel properties of forest residues recovered from Eucalyptus saligna and E. urophylla × E. grandis stands at seven years old in five chip production scenarios. A forest inventory was conducted to estimate the dry biomass, followed by full-tree harvesting with minimum stem diameters equal to 8, 10, 12, and 14 cm for pulpwood, as well as the full trees for energy purposes (treatments). Moisture, volatile matter, fixed carbon, ash contents, and higher and lower heating values of chips were evaluated. The dry biomass was compared between stands by the t-test (α = 0.05) and the fuel properties were assessed between minimum stem diameters in the same forest stand by the Tukey’s test (α = 0.05). Higher chip moisture was obtained in the larger minimum stem diameter, since it showed an increased up to 88% in moisture for the E. urophylla × E. grandis stand. Volatile matter, fixed carbon, and ash results showed that the recovered residues of E. saligna were more susceptible to variations in minimum stem diameters, with up to 53% reduction in ash content between the smallest diameter and full trees. Higher and lower heating values showed non-statistical differences between the minimum stem diameters in Eucalyptus stands

A quantitative study of pitch registers in string quartets opus 17, by Joseph Haydn

In this paper, we present an exploratory study of the pitch registers on the string quartets Opus 17, by Joseph Haydn, according to a quantitative approach. This subject is relevant because the pitch registers studies have revealed noteworthy issues in the Musical Analysis area, the statistical techniques help to detect musical subtleties with a small potential for bias, and because on this corpus, Haydn has established standards for the string quartet genre. The pitch registers study allowed us to identify relevant musical aspects in the repertoire, understand the role of extreme registers in the form segmentation, and observe the prominence of the development and second theme sections, and the feasibility of the quantitative methods. We present a brief theoretical foundation, the methodological framework, the results of the investigation on the quartets' instrument pitches, a discussion about these results, and the conclusions. Keywords: Pitch register, Quantitative analysis, Digital Musicology, String quartet, Joseph Hayd