Computational and theoretical aspects of a grain-boundary model that accounts for grain misorientation and grain-boundary orientation

A detailed theoretical and numerical investigation of the infinitesimal single-crystal gradient plasticity and grain-boundary theory of Gurtin (2008) "A theory of grain boundaries that accounts automatically for grain misorientation and grain-boundary orientation". Journal of the Mechanics and Physics of Solids 56 (2), 640-662, is performed. The governing equations and flow laws are recast in variational form. The associated incremental problem is formulated in minimization form and provides the basis for the subsequent finite element formulation. Various choices of the kinematic measure used to characterize the ability of the grain boundary to impede the flow of dislocations are compared. An alternative measure is also suggested. A series of three-dimensional numerical examples serve to elucidate the theory

Review on Slip Transmission Criteria in Experiments and Crystal Plasticity Models

A comprehensive overview is given of the literature on slip transmission criteria for grain boundaries in metals, with a focus on slip system and grain boundary orientation. Much of this extensive literature has been informed by experimental investigations. The use of geometric criteria in continuum crystal plasticity models is discussed. The theoretical framework of Gurtin (2008, J. Mech. Phys. Solids 56, p. 640) is reviewed for the single slip case. This highlights the connections to slip transmission criteria from the literature that are not discussed in the work itself. Different geometric criteria are compared for the single slip case with regard to their prediction of slip transmission. Perspectives on additional criteria, investigated in experiments and used in computational simulations, are given.Comment: in Journal of Materials Science, 201

The equation of state of neutron matter, symmetry energy, and neutron star structure

We review the calculation of the equation of state of pure neutron matter using quantum Monte Carlo (QMC) methods. QMC algorithms permit the study of many-body nuclear systems using realistic two- and three-body forces in a nonperturbative framework. We present the results for the equation of state of neutron matter, and focus on the role of three-neutron forces at supranuclear density. We discuss the correlation between the symmetry energy, the neutron star radius and the symmetry energy. We also combine QMC and theoretical models of the three-nucleon interactions, and recent neutron star observations to constrain the value of the symmetry energy and its density dependence.Comment: 11 pages, 11 figure

KC Two-Way Clustering Algorithms For Multi-Child Semantic Maps In Image Mining

Image mining is now a thriving and expanding field of computer science research. Image mining is linked to the advancement of data mining in image preparation. Image mining is used to extract hidden information and in other situations where the photos do not clearly describe the situation. Image mining combines machine learning, data handling, application autonomy, and image preparation concepts. Semantic maps are used to visualize image data stored in image databases. We recommend using Multi-Child Semantic Maps to build semantic maps which fully display the image. In this study, we propose two path clustering on Multi-Child Semantic Maps (MCSM) using the K-C Means Clustering Algorithm, also known as the MCSMK-C algorithm. This algorithm causes image clustering and instructs the mining system to look at the image's top area. When mining, the MCSMK-C algorithm considers the X and Y coordinates. The system looks for groups by examining each object's territory in the database, and it saves a region if it contains more objects than the required number

Aortic arch tortuosity with PHACE syndrome : a rare case scenario

PHACE syndrome is a rare neurocutaneous disorder characterised by an association of infantile haemangiomas with structural anomalies of brain, cerebral vasculature, eye, aorta and chest wall.1 Coarctation of aorta (COA) is most the common cardiac anomaly reported in PHACE syndrome. COA or interrupted aortic arch in PHACE is unique and complex both in location and character compared to the typical coarctation anatomy. Arterial tortuosity of the cerebral vasculature has been well described in literature in PHACE syndrome. We present a rare case of tortuous aortic arch continuing as descending aorta in an infant with PHACE syndrome.peer-reviewe

Sex determination from adult human humerus by discriminant function analysis

Background: Sex determination of unidentified skeletal remains from crime scenes or excavation sites is an important component in the development of the biological profile in forensics, anthropology and bioarchaeology. The purpose of this research is to determine whether sexing of unknown adult human humerus bones can be done by applying values of morphometric parameters and formulae generated by present study on adult human humerus bones of known sex and to find out the best parameters for sex determination.Methods: Various metric measurements were recorded using osteo metric board, measuring tape, non-elastic thread, sliding calipers and Vernier calipers on adult human humerus bones.Results: Sex was correctly estimated by using stepwise discriminant function analysis, for the clavicle 100% of males and 95% of females, with a total accuracy of 98.1%. Direct discriminant function analysis, correct estimated sex for the clavicle was 100% in males and 95% in females with a total accuracy of 98.1%.Conclusions: Present study exhibited better classification accuracy for multiple variables than those of single variables, the most discriminating variables in stepwise analysis are the weight, total length, transverse diameter of head, circumference of midshaft, trochlear width, capitulum width. In direct analysis, the single most useful variable was the transverse diameter of head