University of Stuttgart

About: University of Stuttgart is a education organization based out in Stuttgart, Germany. It is known for research contribution in the topics: Laser & Finite element method. The organization has 27715 authors who have published 56370 publications receiving 1363382 citations. The organization is also known as: Universität Stuttgart.

Carbon Fibers: Precursors, Manufacturing, and Properties

Abstract: The properties, structure, and processing of carbon fibers are reviewed. Carbon fibers are made from several precursors, with PAN being the dominating precursor in the market. Carbon fibers have high tensile strength, high modulus (up to the theoretical limit of around 1000 GPa), and low density, depending on the structure and processing in very limited combinations. Both the structure and composition of the precursor affect the properties of the resulting carbon fibers significantly. Although the essential processes for carbon fiber production are similar, different precursors require different processing conditions in order to achieve improved performance. Future developments are discussed.

Parametric analysis of queuing networks

Abstract: We consider a queuing network with M exponential service stations and with N customers. We study the behavior of a subsystem σ, which has a single node as input and a single node as output, when th...

Topographical pathways guide chemical microswimmers

Abstract: Achieving control over the directionality of active colloids is essential for their use in practical applications such as cargo carriers in microfluidic devices. So far, guidance of spherical Janus colloids was mainly realized using specially engineered magnetic multilayer coatings combined with external magnetic fields. Here we demonstrate that step-like submicrometre topographical features can be used as reliable docking and guiding platforms for chemically active spherical Janus colloids. For various topographic features (stripes, squares or circular posts), docking of the colloid at the feature edge is robust and reliable. Furthermore, the colloids move along the edges for significantly long times, which systematically increase with fuel concentration. The observed phenomenology is qualitatively captured by a simple continuum model of self-diffusiophoresis near confining boundaries, indicating that the chemical activity and associated hydrodynamic interactions with the nearby topography are the main physical ingredients behind the observed behaviour. Self-propelled colloids can be used as cargo carriers, but it is challenging to control their motion without external fields. Here, Simmchen et al. use submicron patterns on a solid substrate to effectively confine the motion of the chemically active Janus microswimmers along the edges of the patterns.