Structural Transformation in Pyrolytic Graphite Accompanying Deformation

Pyrolytic graphite deformation and structural transformatio

The genotype-phenotype relationship in multicellular pattern-generating models - the neglected role of pattern descriptors

Background: A deep understanding of what causes the phenotypic variation arising from biological patterning processes, cannot be claimed before we are able to recreate this variation by mathematical models capable of generating genotype-phenotype maps in a causally cohesive way. However, the concept of pattern in a multicellular context implies that what matters is not the state of every single cell, but certain emergent qualities of the total cell aggregate. Thus, in order to set up a genotype-phenotype map in such a spatiotemporal pattern setting one is actually forced to establish new pattern descriptors and derive their relations to parameters of the original model. A pattern descriptor is a variable that describes and quantifies a certain qualitative feature of the pattern, for example the degree to which certain macroscopic structures are present. There is today no general procedure for how to relate a set of patterns and their characteristic features to the functional relationships, parameter values and initial values of an original pattern-generating model. Here we present a new, generic approach for explorative analysis of complex patterning models which focuses on the essential pattern features and their relations to the model parameters. The approach is illustrated on an existing model for Delta-Notch lateral inhibition over a two-dimensional lattice. Results: By combining computer simulations according to a succession of statistical experimental designs, computer graphics, automatic image analysis, human sensory descriptive analysis and multivariate data modelling, we derive a pattern descriptor model of those macroscopic, emergent aspects of the patterns that we consider of interest. The pattern descriptor model relates the values of the new, dedicated pattern descriptors to the parameter values of the original model, for example by predicting the parameter values leading to particular patterns, and provides insights that would have been hard to obtain by traditional methods. Conclusion: The results suggest that our approach may qualify as a general procedure for how to discover and relate relevant features and characteristics of emergent patterns to the functional relationships, parameter values and initial values of an underlying pattern-generating mathematical model

Blood flow dynamics in patient specific arterial network in head and neck

This paper shows a steady simulation of blood flow in the major head and neck arteries as if they had rigid walls, using patient specific geometry and CFD software FLUENT R . The Artery geometry is obtained by CT–scan segmentation with the commercial software ScanIPTM. A cause and effect study with various Reynolds numbers, viscous models and blood fluid models is provided. Mesh independence is achieved through wall y+ and pressure gradient adaption. It was found, that a Newtonian fluid model is not appropriate for all geometry parts, therefore the non–Newtonian properties of blood are required for small vessel diameters and low Reynolds numbers. The k–! turbulence model is suitable for the whole Reynolds numbe

Relaxation in yield stress systems through elastically interacting activated events

We study consequences of long-range elasticity in thermally assisted dynamics of yield stress materials. Within a two-dimensinal mesoscopic model we calculate the mean-square displacement and the dynamical structure factor for tracer particle trajectories. The ballistic regime at short time scales is associated with a compressed exponential decay in the dynamical structure factor, followed by a subdiffusive crossover prior to the onset of diffusion. We relate this crossover to spatiotemporal correlations and thus go beyond established mean field predictions.Comment: 5 pages, 2 figures, to appear in PR

Why must we work in the phase space?

We are going to prove that the phase-space description is fundamental both in the classical and quantum physics. It is shown that many problems in statistical mechanics, quantum mechanics, quasi-classical theory and in the theory of integrable systems may be well-formulated only in the phase-space language.Comment: 130 page

Tensile Properties of Five Low-Alloy and Stainless Steels Under High-Heating-Rate and Constant-Temperature Conditions

Tensile properties of five low-alloy and stainless steels under high heating rate and constant temperatur