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A Bidimensional Finite Element Study of Crack Propagation in Austempered Ductile Iron

Computers, Materials & Continua 2023年第11期77卷 1411-1424页

作者： gustavo von zeska de frança Roberto Luís de Assumpção Marco Antonio Luersen Carlos Henrique da Silva department of Mechanical Engineering Federal University of Technology–ParanáCuritiba81280-340Brazil

Austempered ductile iron(ADI)is composed of an ausferritic matrix with graphite nodules and has a wide range of applications because of its high mechanical strength,fatigue resistance,and wear resistance compared to other cast *** amount and size of the nodules can be controlled by the chemical composition and austenitizing *** the nodules have lower stiffness than the matrix and can act as stress concentrators,they influence crack ***,the crack propagation mechanism in ADI is not yet fully *** this study,we describe a numerical investigation of crack propagation in ADIs subjected to cyclic *** numerical model used to calculate the stress intensity factors in the material under the given conditions is built with the aid of Abaqus commercial finite element *** crack propagation routine,which is based on the Paris law,is implemented in *** results of the simulation show that the presence of a nodule generates a shear load on the crack ***,even under uniaxial tensile loading,the presence of the nodule yields a non-zero stress intensity factor in mode II,resulting in a deviation in the crack propagation *** is the primary factor responsible for changing the crack propagation direction towards the *** the parameters,for example,increasing the nodule size or decreasing the distance between the nodule and crack tip,can intensify this *** simulations comparing two different ADIs with the same graphite fraction area,the crack in the material with more nodules reaches another nodule in a shorter propagation time(or shorter number of cycles).This suggests that the high fatigue resistance observed in ADIs may be correlated with the number of nodules intercepted by a crack and the additional energy required to nucleate new *** summary,these findings contribute to a better understanding of crack propagation in ADIs,provide insights into the relationship between the presence

关键词： Austempered ductile iron(ADI) fatigue crack propagation graphite nodule

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Physiological and Biochemical Characterization of JilóSeeds (Solanum gilo) in Different Harvest Times

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American Journal of Plant Sciences 2017年第10期8卷 2569-2595页

作者： Marcus Vinicius Prado Alves Edila Vilela de Resende von Pinho Heloisa Oliveira Dos Santos gustavo Costa Prado Alves Rucyan Walace Pereira Agriculture department Federal University of Lavras Lavras Brazil

The evaluation of seed quality during the development process is important for the definition of the moment of harvest. In this context, the objective in this study was to evaluate the quality of Jiló seeds during development through physiological, biochemical and electrophoretic tests of enzymes. Six genetic materials, JIL white, JIL 001, JIL 005, JIL 006, H1 and H2 were used. Fruits were harvested at 35, 40, 45 days after anthesis (DAA). A total of 50% of all fruits harvested at 45 DAA remained at rest for seven days which were labeled as 45 DAAr. The seeds at each maturation stage were extracted from the fruits and evaluated by water content, weight of one thousand seeds, electric conductivity, germination, germination speed index, seedling emergence, and seedling emergence rate index. The chemical composition of the seeds was also evaluated, as well as the expression of the enzymes esterase, isocitrate lyase, malate dehydrogenase, alcohol dehydrogenase, superoxide dismutase, catalase, peroxidase and endo-β-mannanase. The highest values of germination and vigor were found in seeds harvested at 45 DAA and 45 DAAr, mainly for hybrids H1 and H2. The highest values of lipids and proteins and lower carbohydrates were found in the most immature seeds of Jiló. The enzymes analyzed showed higher expression in the initial stages of development, however reduced with the advancement of the maturation stage. Endo-β-mannanase expression increased with seed development. Jiló seeds harvested at 45 DAAr presented the highest of germination and vigor values. This “being” considered as the ideal harvest point.

关键词： Seed Quality Germination Enzyme Harvesting Point Seed development

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Gravitational and Quantum Effects in Neuron Function

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Journal of Life Sciences 2016年第6期10卷 273-278页

作者： gustavo Rodrigues Ferreira Gomes International Center of Condensed Matter Physics University of Brasilia (UnB) Brasilia 70297-400 Distrito Federal Brazil

The relation between microtubules architecture in the cytoskeletal structure inside the dendrites and soma and the emergence of neuron function and firing action potential crosses the tiny line between physics and biology. As decoherence is a fundamental mechanism in some biological process such as photosynthesis and others examples, the gravitational quantum approach may contribute to elucidate if neuron function really emerges from quantum coherence in neuronal microtubules. The Einstein equation correlates the stress-energy tensor Tμv to a specific divergence-free combination Ricci tensor Rμv and the metric. In the semiclassical formulation, we have Gμv = Rμv -1/2gμvR=8πG/C^4〈ψ｜μvψ〉 which describes the quantum field in curved space-time geometry. But for a more precise equation in relation to the stress-energy tensor, we know that in a non-zero temperature, the wave-function is not enough to describe the physical reality. A more precise equation demands a formulation in the density-matrix form but for now there is no Diosi-Penrose model with density-matrix formulation. Such a density-matrix description can be viewed as a probability mixture of different wave-functions. Using some algebra and rules related to the mathematical manipulation of the density-matrix applied to operators, such the stress energy tensor, we found the von Neumann-Einstein equation for the general relativity equation in the density matrix operator form, Gμv = 8πG/C^4Tr[pTμv]. Thus density-matrix operator--instead of just a wave function of pure states--applied to the stress-energy tensor gives the curvature of space time, given by Einstein tensor, Gμv. The quantum fluctuation in the gravitational space-time field might feed back to decohere the quantum density-matrix. As long as decoherence can be viewed as the loss of information from a system to the environment, the density-matrix p is also related to that process and considering the measurement problem, density-matrix /garter is a more

关键词： Semiclassical equation quantum gravity decoherence microtubulin neuron function.

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Complementarity between quantum coherence and mixedness:a majorization approach

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Communications in Theoretical Physics 2023年第5期75卷 73-83页

作者： Yanet Alvarez Marcelo Losada Mariela Portesi gustavo M Bosyk Instituto de Física La Plata CONICET–UNLP1900 La PlataArgentina Facultad de Ciencias Exactas Universidad Nacional de La Plata1900 La PlataArgentina Facultad de Matemática AstronomíaFísica y ComputaciónUniversidad Nacional de Córdoba5000 CórdobaArgentina

Quantum coherence is a relevant resource for various quantum information processing tasks,but it is fragile since it is generally affected by environmental *** is reflected in the loss of purity of the system,which in turn limits the amount of quantum coherence of *** a consequence,a complementarity relation between coherence and mixedness *** works characterize this complementarity through inequalities between theℓ1-norm of coherence and linear entropy,and between the relative entropy of coherence and von Neumann ***,coherence-mixedness complementarity is expected to be a general feature of quantum systems,regardless of the measures ***,an alternative approach to coherence-mixedness complementarity,based on majorization theory,is *** quantifiers of coherence and mixedness,namely the coherence vector and the spectrum,respectively,are used,instead of scalar measures.A majorization relation for the tensor product of both vectorial quantifiers is obtained,capturing general aspects of the trade-off between coherence and *** optimal bound for qubit systems and numerical bounds for qutrit systems are ***,coherence-mixedness complementarity relations are derived for a family of symmetric,concave and additive *** results provide a deeper insight into the relation between quantum coherence and mixedness.

关键词： coherence mixedness complementarity majorization

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