Bending and springback prediction method based on multi-scale finite element analyses for high bendability and low springback sheet generation

In this study, a sheet bendability and springback property evaluation technology through bending test simulations is newly developed using our multi-scale finite element analysis code, which is based on the crystallographic homogenization method

Multiscale analysis of piezoelectric material by using EBSD-measured realistic model

Material properties of a polycrystal piezoelectric ceramic, a barium titanate BaTiO3, were analyzed by the two-scale crystallographic homogenization method. Threedimensional (3-D) micro-finite element (FE) model was constructed based on the electron backscatter diffraction (EBSD) measured crystal orientation distribution images. The images are piled up to a 3-D voxel data of crystal orientation distribution by repeating mechanically and chemically polishing, and EBSD measurement of the ceramic. We obtained 13 EBSD images of 128×100 pixels, which measurement interval was 0.635μm in-plane and the average amount of polishing was 1.66μm in thickness (normal) direction of specimen. Each voxel of EBSD was assigned into 8-node solid FE in-plane with maintaining resolution of EBSD measurement, and was divided into three FEs along thickness direction with same crystal orientation, because of improvement of aspect ratio of FE. The total number of FEs was 499,200 (=128×100×13×3) which corresponded to over two millions degrees of freedom. In order to realize a large-scale micro-analysis using EBSD-measured voxel FE model, the coupled problem of the piezoelectric material was solved by parallel conjugate gradient (CG) method combined with the block Gauss-Seidel (BGS) method. The coupled micro-FE equation to obtain characteristic function vectors was separated into two linear equations, such as the elastic deformation and electrostatic analyses, by employing the BGS method, and then the equations were solved by the parallel CG solver while substituting coupling terms each other. Therefore, nested iterative scheme was constructed on a PC cluster. In addition, the representative volume element (RVE) size was determined based on the orientation distribution function analyses of EBSD voxel data. The least RVE size was 25,000μm3, which corresponded to include 150 crystal grains

Evaluation of frictional forces in vitro between brackets and orthodontic wires in upper cusp distalization according to the Tweed-Merrifield Sequential Directional Force Technique

Orientador: Maria Beatriz Borges de Araujo MagnaniTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: O objetivo desse estudo foi avaliar in vitro a força de atrito gerada na mecânica de distalização do canino superior pelo uso do gancho ¿J¿ na Técnica da Força Direcional Seqüencial de Tweed-Merrifield, de acordo com as variáveis: tipo e marcas dos braquetes; espessura e marcas dos fios; técnica de amarração e análise das superfícies dos fios e braquetes em microscopia eletrônica de varredura, microscopia de força atômica, além de rugosímetro. Foram utilizados 192 braquetes Edgewise de aço inoxidável de dois tipos e duas marcas comerciais e duas marcas de fios ortodônticos (Morelli, Sorocaba, São Paulo, Brasil e GAC, Central Islip, Nova Iorque, EUA) de aço inoxidável em quatro espessuras, amarrados por ligadura metálica e elastomérica em meio seco e à temperatura ambiente. Foi utilizada uma placa de acrílico retangular simulando um segmento de aparelho fixo composto por quatro braquetes duplos. Cada fio a ser testado teve suas extremidades dobradas justas aos braquetes terminais para que não deslizasse na canaleta e foi amarrado aos braquetes com ligadura de aço inoxidável. A placa de acrílico juntamente com o segmento do fio montado foi fixada no mordente da base da máquina de ensaio universal Instron 4411 (Instron Ltd., High Wycombe, Bucks, Reino Unido) de maneira a ficar posicionada em 45° em relação ao solo, o que foi realizado com o auxílio do esquadro, simulando a angulação do aparelho extrabucal gancho ¿J¿ com o plano oclusal, durante a mecânica de distalização do canino superior. O braquete foi puxado a velocidade de 0,5mm/minuto através do segmento do fio por uma distância de 5mm. Os testes foram repetidos três vezes, trocando-se a combinação braquete/fio a ser testada para cada três grupos. Os valores médios foram obtidos e a força de atrito foi calculada. Após o recorte das canaletas dos braquetes e limpeza dos fios e braquetes, esses foram analisados em microscopia eletrônica de varredura e de força atômica. Além disso, sobre a superfície dos fios foi efetuada a leitura da rugosidade de superfície em micrometros. Os dados foram submetidos à Análise de Variância e ao teste de Tukey (5%). Concluiu-se que: os braquetes duplos proporcionaram maior atrito do que os braquetes simples; os braquetes e fios da marca Morelli proporcionaram maior atrito do que os da GAC; quanto maior a espessura dos fios, maior foi o atrito; a técnica de amarração que gerou maior atrito foi com ligadura elástica quando comparada à ligadura de aço inoxidável; a rugosidade do fio diminuiu com o uso em alguns casos e os fios da marca GAC apresentaram qualitativamente lisura de superfície superior ao da marca MorelliAbstract: This study aimed to evaluate in vitro frictional forces that result from upper cusp distalization due to using the J-Hook, according to the Tweed-Merrifield Sequential Directional Force technique; variables were: bracket type and manufacturer, wire diameter and manufacturer, ligation method and microscopic surface analysis of brackets and wires. One hundred and ninety-two stainless steel Edgewise brackets, of two different types and manufacturers were used, ligated to orthodontic wires of four diameters and two manufacturers (Morelli, Sorocaba, São Paulo, Brazil and GAC, Central Islip, New York, USA) by means of metallic and elastomeric ligatures, at extraoral environment and ambient temperature. A rectangular acrylic plate was manufactured, imitating a fixed appliance section of four double brackets. The ends of each wire were tightly bended to the terminal brackets, in order to eliminate sliding, and were fixed to the brackets by stainless steel ligatures. Each sample, comprising the acrylic plate, as well as the bracket and wire section, was fixed unto a Instron 4411 testing machine (Instron Ltd., High Wycombe, Bucks, United Kingdom), so that each of them was at a 45º inclination, relative to the horizontal plane, thus imitating the extraoral position of the J-hook, relative to the occlusal plane, during upper cusp distalization. The bracket was pulled for 5mm sliding at a speed of 0.5mm/minute. Tests were performed other three times, each for a different bracket/wire combination, over the three groups. The mean values were obtained and frictional forces were calculated. After cutting bracket slots and cleaning wires and brackets, these were analyzed by scanning electron and atomic force microscopy. Also, surface rugosity, in micrometers, was evaluated. Data underwent Variance analysis and Tukey test (5%). Final observations were: twin brackets provide greater frictional forces; brackets and wires manufactured by Morelli showed greater frictional forces than those by GAC; the larger the wire diameter, the greater the frictional forces; elastomeric ligatures resulted in greater friction than stainless steel ligatures; usage made the wires less roughness just in some cases, and GAC manufactured wires presented greater surface smoothness than those by MorelliDoutoradoOrtodontiaDoutor em Radiologia Odontológic

Cophenetic correlation analysis as a strategy to select phylogenetically informative proteins: an example from the fungal kingdom

<p>Abstract</p> <p>Background</p> <p>The construction of robust and well resolved phylogenetic trees is important for our understanding of many, if not all biological processes, including speciation and origin of higher taxa, genome evolution, metabolic diversification, multicellularity, origin of life styles, pathogenicity and so on. Many older phylogenies were not well supported due to insufficient phylogenetic signal present in the single or few genes used in phylogenetic reconstructions. Importantly, single gene phylogenies were not always found to be congruent. The phylogenetic signal may, therefore, be increased by enlarging the number of genes included in phylogenetic studies. Unfortunately, concatenation of many genes does not take into consideration the evolutionary history of each individual gene. Here, we describe an approach to select informative phylogenetic proteins to be used in the Tree of Life (TOL) and barcoding projects by comparing the cophenetic correlation coefficients (CCC) among individual protein distance matrices of proteins, using the fungi as an example. The method demonstrated that the quality and number of concatenated proteins is important for a reliable estimation of TOL. Approximately 40–45 concatenated proteins seem needed to resolve fungal TOL.</p> <p>Results</p> <p>In total 4852 orthologous proteins (KOGs) were assigned among 33 fungal genomes from the Asco- and Basidiomycota and 70 of these represented single copy proteins. The individual protein distance matrices based on 531 concatenated proteins that has been used for phylogeny reconstruction before <abbrgrp><abbr bid="B14">14</abbr></abbrgrp> were compared one with another in order to select those with the highest CCC, which then was used as a reference. This reference distance matrix was compared with those of the 70 single copy proteins selected and their CCC values were calculated. Sixty four KOGs showed a CCC above 0.50 and these were further considered for their phylogenetic potential. Proteins belonging to the cellular processes and signaling KOG category seem more informative than those belonging to the other three categories: information storage and processing; metabolism; and the poorly characterized category. After concatenation of 40 proteins the topology of the phylogenetic tree remained stable, but after concatenation of 60 or more proteins the bootstrap support values of some branches decreased, most likely due to the inclusion of proteins with lowers CCC values. The selection of protein sequences to be used in various TOL projects remains a critical and important process. The method described in this paper will contribute to a more objective selection of phylogenetically informative protein sequences.</p> <p>Conclusion</p> <p>This study provides candidate protein sequences to be considered as phylogenetic markers in different branches of fungal TOL. The selection procedure described here will be useful to select informative protein sequences to resolve branches of TOL that contain few or no species with completely sequenced genomes. The robust phylogenetic trees resulting from this method may contribute to our understanding of organismal diversification processes. The method proposed can be extended easily to other branches of TOL.</p

Soil and plant factors driving the community of soil-borne microorganisms across chronosequences of secondary succession of chalk grasslands with a neutral pH

Although soil pH has been shown to be an important factor driving microbial communities, relatively little is known about the other potentially important factors that shape soil-borne microbial community structure. This study examined plant and microbial communities across a series of neutral pH fields (pH=7.0-7.5) representing a chronosequence of secondary succession after former arable fields were taken out of production. These fields ranged from 17 to >66 years since the time of abandonment, and an adjacent arable field was included as a reference. Hierarchical clustering analysis, nonmetric multidimensional scaling and analysis of similarity of 52 different plant species showed that the plant community composition was significantly different in the different chronosequences, and that plant species richness and diversity increased with time since abandonment. The microbial community structure, as analyzed by phylogenetic microarrays (PhyloChips), was significantly different in arable field and the early succession stage, but no distinct microbial communities were observed for the intermediate and the late succession stages. The most determinant factors in shaping the soil-borne microbial communities were phosphorous and NH4+. Plant community composition and diversity did not have a significant effect on the belowground microbial community structure or diversit

A new crystal plasticity constitutive equation based on crystallographic misorientation theory

Since plastic deformation of polycrystal sheet metal is greatly affected by its initial and plastic deformed textures, multi-scale finite element (FE) analysis based on homogenization with considering micro-polycrystal morphology is required [1]. We formulated a new crystal plasticity constitutive equation to introduce not only the effect of crystal orientation distribution, but also the size of crystal grain and/or the effect of crystal grain boundary for the micro-FE analysis. The hardening evolution equation based on strain gradient theory [2], [3] was modified to introduce curvature of crystal orientation based on crystallographic misorientation theory. We employed two-scale structure, such as a microscopic polycrystal structure and a macroscopic elastic/plastic continuum. Our analysis code predicts the plastic deformation of polycrystal metal in the macro-scale, and simultaneously the crystal texture and misorientation evolutions in the micro-scale. In this study, we try to reveal the relationship between the plastic deformation and the microscopic crystal misorientation evolution by using the homogenized FE procedure with the proposed crystal plasticity constitutive equation. The crystallographic misorientation evolution, which affects on the plastic deformation of FCC polycrystal metal, was investigated by using the multi-scale FE analysis. We confirmed the availability of our analysis code employing the new constitutive equation through the comparison of a uniaxial tensile problem with the numerical result and the experimental one

Microscale electrical contact resistance analysis for resistance spot welding

Electrical contact resistance is an important parameter for resistance spot welding. In this study, a microscale electrical contact resistance analysis method is pro- posed for resistance spot welding. The microscale electrical contact resistance analysis method is combination of an elasto–plastic large deformation contact analysis and an electric current analysis. The electric current analysis is performed for deformed shape of asperity. The tendency of the electrical contact resistance on contact pressure and tem- perature for the electrical contact resistance analysis agrees with that for Babu’s electrical contact resistance model. A multiscale coupled analysis method is also proposed for resistance spot welding. The multiscale analysis consists of macroscale elasto–plastic large deformation contact, electric current and thermal conduction triply coupled analysis and microscale electrical contact resistance analysis. It is confirmed that the resistance spot welding analysis without measurement of electrical contact resistance can be performed by using the microscale electrical contact resistance analysis

Intraspecific Evolution of Rhizoctonia solani AG-1 IA Associated with Soybean and Rice in Brazil based on Polymorphisms at the ITS-5.8S rDNA Operon

Rhizoctonia solani AG-1 IA causes leaf blight on soybean and rice. Despite the fact that R. solani AG-1 IA is a major pathogen affecting soybean and rice in Brazil and elsewhere in the world, little information is available on its genetic diversity and evolution. This study was an attempt to reveal the origin, and the patterns of movement and amplification of epidemiologically significant genotypes of R.solani AG-1 IA from soybean and rice in Brazil. For inferring intraspecific evolution of R. solani AG-1 IA sampled from soybean and rice, networks of ITS-5.8S rDNA sequencing haplotypes were built using the statistical parsimony algorithm from Clement et al. (2000) Molecular Ecology 9: 1657-1660. Higher haplotype diversity (Nei M 1987, Molecular Evolutionary Genetics Columbia University Press, New york: 512p.) was observed for the Brazilian soybean sample of R. solani AG-1 IA (0.827) in comparison with the rest of the world sample (0.431). Within the south-central American clade (3-2), four haplotypes of R.solani AG-1 IA from Mato Grosso, one from Tocantins, one from Maranhão, and one from Cuba occupied the tips of the network, indicating recent origin. The putative ancestral haplotypes had probably originated either from Mato Grosso or Maranhão States. While 16 distinct haplotypes were found in a sample of 32 soybean isolates of the pathogen, the entire rice sample (n=20) was represented by a single haplotype (haplotype 5), with a worldwide distribution. The results from nested-cladistic analysis indicated restricted gene flow with isolation by distance (or restricted dispersal by distance in nonsexual species) for the south-central American clade (3-2), mainly composed by soybean haplotype

Crystal texture evolution analyses in metal drawing processes by using two-scale finite element method

Recently, the crystallographic control technology in the aluminum wire drawing process has been a key technology in the aluminum industries, which produces high-strength wires for the electric, automotive and aircraft parts. This newly proposed “process metallurgy” computational technology in the industrial forming process consists of the two-scale finite element (FE) analyses and the optimum design algorithm.We developed two-scale FE analyses code based on the crystallographic homogenization method by considering the hierarchical structure of polycrystal aluminium alloy metal. It can be characterized as the combination of two-scale structure, such as the microscopic polycrystal structure and the macroscopic elastic plastic continuum. Micro polycrystal structure is modelled as a three dimensional representative volume element (RVE). RVE is featured as 3x3x3 eight-nodes solid finite elements, which has totally 216 crystal orientations. This FE analyses code can predict the deformation, strain and stress evolutions in the wire drawing processes in the macro-scale, and simultaneously the crystal texture and hardening evolutions in the micro-scale. In this study, we analyzed the texture evolution in the “three passes” wire drawing processes by using our two-scale FE analyses code under conditions of various drawing angles of die. We evaluated the texture evolution in the surface and center regions of the wire cross section, and to clarify the effects of processing conditions on the texture evolution