Fully-Coupled Balanced-Force VOF Framework for Arbitrary Meshes with Least-Squares Curvature Evaluation from Volume Fractions

A fully-coupled balanced-force numerical framework for two-phase flows with surface tension on arbitrary collocated meshes is presented, including a novel method to evaluate the curvature from volume fractions. The presented framework reduces the imbalances at the interface to solver tolerance and provides stable and reliable results for density ratios of 10⁶ and larger. The new method to evaluate the curvature is based on a least-squares fit, providing better or equal accuracy compared to implementations found in the literature, which are generally limited to structured meshes, and the accuracy on Cartesian and tetrahedral meshes is shown to be comparable.     

Locally adaptive Bayesian P-splines with a Normal-Exponential-Gamma prior

An implementation of locally adaptive penalized spline smoothing using a class of heavy-tailed shrinkage priors for the estimation of functional forms with highly varying curvature or discontinuities is presented. These priors utilize scale mixtures of normals with locally varying exponential-gamma distributed variances for the differences of the P-spline coefficients. A fully Bayesian hierarchical structure is derived with inference about the posterior being based on Markov Chain Monte Carlo techniques. Three increasingly flexible and automatic approaches are introduced to estimate the spatially varying structure of the variances. An extensive simulation study for Gaussian, Poisson, and Binomial responses shows that the performance of this approach on a number of benchmark functions is competitive to that of previous approaches. Results from applications with Gaussian and Poisson responses support the simulation results.     

Reconstruction of graphs based on random walks

The analysis of complex networks is of major interest in various fields of science. In many applications we face the challenge that the exact topology of a network is unknown but we are instead given information about distances within this network. The theoretical approaches to this problem have so far been focusing on the reconstruction of graphs from shortest path distance matrices. Often, however, movements in networks do not follow shortest paths but occur in a random fashion. In these cases an appropriate distance measure can be defined as the mean length of a random walk between two nodes — a quantity known as the mean first hitting time.In this contribution we investigate whether a graph can be reconstructed from its mean first hitting time matrix and put forward an algorithm for solving this problem. A heuristic method to reduce the computational effort is described and analyzed. In the case of trees we can even give an algorithm for reconstructing graphs from incomplete random walk distance matrices.     

Modification of CaCO3 precipitation rates by water-soluble nacre proteins

Mineral growth in nacre and other CaCO₃-containing biominerals is controlled by biopolymers. Water-soluble proteins were extracted from nacre of the sea snail Haliotis laevigata by dissolving the mineral phase with 6% acetic acid. The influence of this protein mixture on CaCO₃ precipitation rates was investigated at different concentrations. A well-established assay for measuring the pH-value during CaCO₃ precipitation with and without protein additives was extended by calculating maximum precipitation rates from the pH-values. It could be shown that precipitation rates are greatly influenced by the mixtures of water-soluble nacre proteins. At very low protein concentrations (0.02 μg/ml) a rate enhancement in comparison to the pure supersaturated calcium carbonate solution by a factor of 1.4 was observed. At higher protein concentrations, a strong inhibitory effect occurred, with total inhibition at concentrations of 1.0 μg/ml and higher. Two unspecific proteins (bovine serum albumin and lysozyme) showed little or no modification of precipitation rates. In vivo, the function of the strong inhibition of CaCO₃ precipitation by nacre proteins at higher concentrations is presumably to prevent uncontrolled crystallization in the extrapallial fluid. The rate-enhancing capability of proteins at low concentrations may be explained by the presence of acidic and/or hydrophilic moieties.     

Diesel exhaust particles modulate the tight junction protein occludin in lung cells in vitro

Background  

Using an in vitro triple cell co-culture model consisting of human epithelial cells (16HBE14o-), monocyte-derived macrophages and dendritic cells, it was recently demonstrated that macrophages and dendritic cells create a transepithelial network between the epithelial cells to capture antigens without disrupting the epithelial tightness. The expression of the different tight junction proteins in macrophages and dendritic cells, and the formation of tight junction-like structures with epithelial cells has been demonstrated. Immunofluorescent methods combined with laser scanning microscopy and quantitative real-time polymerase chain reaction were used to investigate if exposure to diesel exhaust particles (DEP) (0.5, 5, 50, 125 μg/ml), for 24 h, can modulate the expression of the tight junction mRNA/protein of occludin, in all three cell types.     

A rule-based weighted rating system forconcrete culverts

This paper demonstrates the use of a rule-based weighted rating system (RWRS) developed for improving the rating of concrete culverts. RWRS combines the qualitative rating based on a guideline commonly used by the Department of Transportation, the quantitative rating based on a regression model, and the inspector's own judgment on the culvert's rating. Weight on each rating is provided by the supervisor. A case study is presented to demonstrate the use of RWRS.     

Modular visions: Referents, context and strategies for database open media works

The processes of constructing meaning in digital database environments entail a paradigm shift from previous models of audio-visual communication. Media emerging from the Electro-mechanical era (film/TV/video) present fixed spatio-temporal linearity and material conditions which objectify and render passive viewer and process. The problematic aspects of cinematic communication were addressed by Latin American filmmakers of the Third Cinema movement. Their concerns and approach presaged and assisted an understanding of the radical redefinition of audio-visual communication possible with digital databases. The conceptual and aesthetic aspirations of Third Cinema artists such as Julio Garcia Espinosa and Fernando Solanas were ultimately contradictory to linear media and find their fitting medium in digital modular construction. The materiality of database expression lacks an intrinsic temporal or spatial state and permits a more dynamic and multidirectional set of power relationships between author/s, piece, viewer/s. Other important referents for contextualising database art are modern art practitioners that rejected linear representational space and fractured the centrality of authorship. The author's own work, ...two, three, many Guevaras, an exploratory database environment, embraces the redefinition of process as artistic expression, the empowerment of interacting generative forces, and serves to illustrate the revolutionary potential of the new media.     

Syndiospecific polymerization of propene under different processes with different bridged [(RPh)2C(Cp)(2,7-BuFlu)]ZrCl2 metallocene catalysts

The synthesis of syndiotactic polypropene was achieved by using new C_S-symmetric ansa-metallocene catalysts of the type [Ph′₂C(Cp)(2,7-^tertBu₂Flu)]ZrCl₂ (Ph′₂=Ph₂, (4-MePh)₂, 3,4′-Me₂Ph₂, (4-OCH₃Ph)₂). Applying these catalysts, the influence of the substitution pattern of the bridge on the polymerization performance can be studied and highly syndiotactic polypropene (rrrr>99%) with high molar masses and high melting temperatures (up to 153 °C) was obtained.Propene was polymerized at different temperatures under four sets of conditions: in toluene solution, bulk, toluene slurry, and gas phase with NaCl as stirred bed material. Methylaluminoxane (MAO) and methylaluminoxane supported on silicagel (MAO/SiO₂) were used as cocatalyst, respectively. In order to estimate the influence of the process on the single site properties of the catalysts, comparisons were made between polymer properties, i.e. microstructure, melting temperature, molar mass, and polymer morphology, thus allowing the effect of the support on the catalyst to be observed.     

Biomechanical assessment of new hand-powered pruning shears

The aim of the study was to assess the biomechanical strains on the hand-wrist system during grapevine pruning with newly designed pruning shears. Surface electromyography of the finger flexor muscle and wrist postures were analyzed in four vineyard workers during actual work with the new and reference hand-powered pruning shears. Due to the large inter-individual differences in biomechanical data observed with both pruning shears, no systematic effect of the new pruning shears on "extreme" flexion/extension (F/E) and ulnar/radial (U/R) wrist deviations was demonstrated. However, the use of the new pruning shears was associated with a higher frequency of "neutral and moderate" U/R deviations (U/R < 20%(max)) and, to a lesser extent, of "neutral and moderate" F/E deviations (F/E < 20%(max)). Due to the small sample of workers, this result must be confirmed in a larger population of vineyard workers.