Quasi-generalized variables

The numerical solution of a system of differential and algebraic equations is difficult, due to the appearance of numerical instabilities. A method is presented here which permits numerical solutions of such a system to be obtained which satisfy the algebraic constraint equations exactly without reducing the order of the differential equations. The method is demonstrated using examples from mechanics

On the GPU computing of massive forming process simulations

This contribution presents a modelling tool for massive forming processes that is based on a particle method. The introduced model is able to represent the realistic behaviour of different types of forming processes. As these systems usually require large amounts of particles, the potential of GPU Computing with CUDA as a possibility for performance enhancement of particle simulations is analyzed as well

Simulating and Evaluating Synchronized Vibrations in Macroscopic Tribological Contacts

High-frequency synchronized vibrations in the friction contact constitute one known triggering mechanism of certain types of NVH phenomena in automotive brakes. Towards an improved understanding of the associated physical processes, vibrations of contact patches in the tribological boundary layer are computed using the Abstract Cellular Automaton simulation program. Various studies are presented, each illustrating unique types of local phenomena and observable global behaviors. For example, simulations are carried out on multiple timescales, enabling investigations into the emergence of global patch coverage states and the resulting vibrational behavior in the tribological contact. Relevant means for analyzing and interpreting these results are introduced, including a qualitative visual representation scheme, frequency analyses of the global coefficient of friction, and a new method for quantifying the synchronization of multiple oscillating bodies

Lipid droplets: a classic organelle with new outfits

Lipid droplets are depots of neutral lipids that exist virtually in any kind of cell. Recent studies have revealed that the lipid droplet is not a mere lipid blob, but a major contributor not only to lipid homeostasis but also to diverse cellular functions. Because of the unique structure as well as the functional importance in relation to obesity, steatosis, and other prevailing diseases, the lipid droplet is now reborn as a brand new organelle, attracting interests from researchers of many disciplines

Mechanisms of leukocyte lipid body formation and function in inflammation

An area of increasingly interest for the understanding of cell signaling are the spatio-temporal aspects of the different enzymes involved in lipid mediator generation (eicosanoid-forming enzymes, phospholipases and their regulatory kinases and phosphatases) and pools of lipid precursors. The compartmentalization of signaling components within discrete and dynamic sites in the cell is critical for specificity and efficiency of enzymatic reactions of phosphorilation, enzyme activation and function. We hypothesized that lipid bodies - inducible non-membrane bound cytoplasmic lipid domains - function as specialized intracellular sites of compartmentalization of signaling with major roles in lipid mediator formation within leukocytes engaged in inflammatory process. Over the past years substantial progresses have been made demonstrating that all enzymes involved in eicosanoid synthesis localize at lipid bodies and lipid bodies are distinct sites for eicosanoid generation. Here we will review our current knowledge on the mechanisms of formation and functions of lipid bodies pertinent to inflammation

On the GPU computing of massive forming process simulations

This contribution presents a modelling tool for massive forming processes that is based on a particle method. The introduced model is able to represent the realistic behaviour of different types of forming processes. As these systems usually require large amounts of particles, the potential of GPU Computing with CUDA as a possibility for performance enhancement of particle simulations is analyzed as well