34 research outputs found
Aspiration of biological viscoelastic drops
Spherical cellular aggregates are in vitro systems to study the physical and
biophysical properties of tissues. We present a novel approach to characterize
the mechanical properties of cellular aggregates using micropipette aspiration
technique. We observe an aspiration in two distinct regimes, a fast elastic
deformation followed by a viscous flow. We develop a model based on this
viscoelastic behavior to deduce the surface tension, viscosity, and elastic
modulus. A major result is the increase of the surface tension with the applied
force, interpreted as an effect of cellular mechanosensing.Comment: 4 pages, 4 figures
Optimierung des Einsatzes von Mehrzweck- und Schwerlast-Geraetetraegern sowie Lkw (als Geraetetraeger) im Strassenbetriebsdienst
Every year large amounts of money must be spent for vehicles and equipment used in the high-way operation services. The main objective of this investigation was therefore to seek areas for cost savings by optimized equipping the vehicles and devices at autobahn and highway surveillance centres through improved use of equipment carriers. In addition to the aspect of economic efficiency, technical, operational, ergonomic and ecological criteria were brought into the evaluation of the vehicle types relevant for the investigation. On the basis of this analysis, recommendations were able to be made on the equipping of autobahn and highway surveillance centres, whereby these recommendations are based in the main on the investigation results obtained on the use of the vehicles in summer months services; an investigation of the use of the vehicles and equipment for the winter services is recommended but has not yet been carried out. In addition to the multipurpose equipment carriers commonly used at the present time-trucks as equipment carriers as well as the newly developed heavy-duty equipment carriers can be put to use very well in the summer-month services. Heavy-duty equipment carriers can be used on the one hand as equipment carriers and, on the other hand, in the same way as large trucks for winter services, road safety work and transporting. The cost comparison calculations carried out show that significant reductions in annual overall costs for autobahn and highway surveillance centres are capable of being obtained in many cases by the use of medium-sized trucks capable of being used as full-value equipment carriers. The savings are achieved by means of a reduction in the number of vehicles at a surveillance centre by reason of better levels of utilization of the existing vehicles or the vehicles to be procured in the future. Accordingly for typical autobahn surveillance centres in rural areas with average levels of traffic and average to unfavourable growth conditions 1 multipurpose equipment carrier as well as 1 universal vehicle are sufficient in addition to 4 conventional trucks. For a highway surveillance centre with an average profile of tasks, the vehicle fleet can be reduced to 3 vehicles (1 conventional truck, 1 multipurpose equipment carrier and 1 universal vehicle). A heavy-duty equipment carrier, a medium-sized truck as equipment carrier or a multipurpose equipment carrier with a permissible overall weight of at least 14 t can be used as the universal vehicle, whereby the selection should be made in accordance with the specific requirements of each surveillance centre. (orig./HK)Available from TIB Hannover: ZA 4681(708)+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman
Einsatzuntersuchung im Strassenbetriebsdienst Taetigkeitsfeld und Auslastung der Fahrzeuge und Geraete und Leistungsermittlung verschiedener Anbaugeraete untersucht in 5 hessischen Strassenmeistereien. Berichtszeitraum: 1985-1986
TIB: FR 244 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman