Die Sanddornbeere, eine C-vitaminreiche, zur Herstellung von Marmelade geeignete Frucht

Ohne Zusammenfassung     

CLSVOF as a fast and mass-conserving extension of the level-set method for the simulation of two-phase flow problems

The modeling of two-phase flows in computational fluid dynamics is still an area of active research. One popular method is the coupling of level-set and volume-of-fluid (CLSVOF), which benefits from the advantages of both approaches and results in improved mass conservation while retaining the straightforward computation of the curvature and the surface normal. Despite its popularity, details on the involved complex computational algorithms are hard to find and if found, they are mostly fragmented and inaccurate. In contrast, this article can be used as a comprehensive guide for an implementation of CLSVOF into the existing level-set Navier–Stokes solvers on Cartesian grids in three dimensions.     

Technical Brief: Fatigue Dimples

This technical brief is intended to warn failure analysts against assuming that dimples indicate overload fracture. Dimples simply mean that microvoid processes were active; these processes can occur in cyclic as well as monotonic fractures. The failure analyst must examine the entire fracture, the macroscopic as well as the microscopic features, to be confident of the cracking mode.     

Mathematical modeling and numerical simulation of freezing processes of a supercooled melt under consideration of density changes

In this paper, we derive a model for the two-phase freezing process of supercooled fluids. Especially, we take density changes along the phase interfaces into account. Thus, besides heat diffusion and the interface phenomena, mass transport and convection in the fluid phase which is given by the full Navier–Stokes equations has to be considered. For the 2D case we implemented an algorithm for the numerical solution of the mathematical model using uniform volume cells for a finite difference discretization. Additionally, the phase boundaries are captured by a surface tracking method. We report on the mathematical model and its derivation, describe the numerical algorithm and present numerical experiments. Received: 11 September 1997 / Accepted: 19 June 1998     

Field-programmable smart-pixel arrays: design, VLSI implementation, and applications

A smart-pixel array is a two-dimensional array of optoelectronic devices that combine optical inputs and outputs with electronic processing circuitry. A field-programmable smart-pixel array (FP-SPA) is a smart-pixel array capable of having its electronic functionality dynamically programmed in the field. Such devices could be used in a diverse range of applications, including optical switching, optical digital signal processing, and optical image processing. We describe the design, VLSI implementation, and applications of a first-generation FP-SPA implemented with the 0.8-microm complementary metal-oxide semiconductor-self-electro-optic effect device technology made available through the Lucent Technologies-Advanced Research Projects Agency Cooperative (Lucent/ARPA/COOP) program. We report spice simulations and experimental results of two sample applications: In the first application, we configure this FP-SPA as an array of free-space optical binary switches that can be used in optical multistage networks. In the second, we configure the device as an optoelectronic transceiver for a dynamically reconfigurable free-space intelligent optical backplane called the hyperplane. We also describe the testing setup and the electrical and the optical tests that demonstrate the correct functionality of the fabricated device. Such devices have the potential to reduce significantly the need for custom design and fabrication of application-specific optoelectronic devices in the same manner that field-programmable gate arrays have largely eliminated the need for custom design and fabrication of application-specific gate arrays, except in the most demanding applications.     

Feature sensitive multiscale editing on surfaces

A novel editing method for large triangular meshes is presented. We detect surface features, such as edge and corners, by computing local zero and first surface moments, using a robust and noise resistant method. The feature detection is encoded in a finite element matrix, passed to an algebraic multigrid (AMG) algorithm. The AMG algorithm generates a matrix hierarchy ranging from fine to coarse representations of the initial fine grid matrix. This hierarchy comes along with a corresponding multiscale of basis functions, which reflect the surface features on all hierarchy levels. We consider either these basis functions or distinct sets from an induced multiscale domain decomposition as handles for surface manipulation. We present a multiscale editor which enables Boolean operations on this domain decomposition and simply algebraic operations on the basis functions. Users can interactively design their favorite surface handles by simple grouping operations on the multiscale of domains. Several applications on large meshes underline the effectiveness and flexibility of the presented tool.     

FlipCut Supertrees: Towards Matrix Representation Accuracy in Polynomial Time

In computational phylogenetics, supertree methods provide a way to reconstruct larger clades of the Tree of Life. The supertree problem can be formalized in different ways, to cope with contradictory information in the input. In particular, there exist methods based on encoding the input trees in a matrix, and methods based on finding minimum cuts in some graph. Matrix representation methods compute supertrees of superior quality, but the underlying optimization problems are computationally hard. In contrast, graph-based methods have polynomial running time, but supertrees are inferior in quality. In this paper, we present a novel approach for the computation of supertrees called FlipCut supertree. Our method combines the computation of minimum cuts from graph-based methods with a matrix representation method, namely Minimum Flip Supertrees. Here, the input trees are encoded in a 0/1/?-matrix. We present a heuristic to search for a minimum set of 0/1-flips such that the resulting matrix admits a directed perfect phylogeny. We then extend our approach by using edge weights to weight the columns of the 0/1/?-matrix. In our evaluation, we show that our method is extremely swift in practice, and orders of magnitude faster than the runner up. Concerning supertree quality, our method is sometimes on par with the “gold standard” Matrix Representation with Parsimony.