Dynamical theory of stability for elastic rods with nonlinear curvature and twist

Considering non-linear terms in the curvature as well as in the twist, the governing boundary value problem for lateral bending of elastic, transverse loaded rods is formulated by means of Hamilton's principle. Using the method of small vibrations, the associated linearized equations of stability are derived, which complete the currently accepted relations. The example of the simplest lateral bending problem illustrates the improved effect of the proposed equations

Modeling and Dynamic Behavior of Electrostatic Tranducers with Distributed Parameters

The dynamics of an electrostatic transducer as a 2-field system with distributed parameters is studied, here in form of a 1-dimensional capacitor composed of a flexible strip with clamped ends and a rigid plate opposite including inductance and resistance effects. Both electrical and mechanical input signals are taken into consideration, and the influence on the electrical charge between the plates as well the relative displacement of the plates is discussed indetail. First, a formulation of the governing non-linear boundary value problem is presented. Next the simplified time-independent boundary value problem is derived when only a polarization DC voltage is applied. Then, the equations of motion describing the dynamic behavior of the transducer in the neighborhood of the steady state are generated. The RITZ method for discretization is introduced to obtain simplified equation sets for approximate solutions. Starting with the roughest 1-term truncation for both displacement and charge to be interpreted as the classical lumped-parameter transducer, the discussion is finally generalized studying truncations of higher order

Effect of early Ambroxol treatment on lung functions in mechanically ventilated preterm newborns who subsequently developed a bronchopulmonary dysplasia (BPD)

AbstractIn a randomized trial in 102 preterm newborns with respiratory distress syndrome (RDS) it has been shown that early Ambroxol treatment (30 mg kg−1over the first 5 days) significantly reduces the incidence of RDS-associated complications [bronchopulmonary dysplasia (BPD), intraventricular haemorrhage, post-natal acquired pneumonia]. The aim of the present analysis was to investigate the effect of Ambroxol treatment on lung function in newborns who developed BPD.Respiratory function testing (RFT) was performed immediately after extubation and at day 28. Tidal volume (VT) and respiratory frequency (f) were measured during tidal breathing using the deadspace free flow-through technique. The lung mechanic parameter VT/maxPeswas determined by measuring the maximal oesophageal pressure changes, maxPes, with a catheter tip pressure transducer.In the placebo group 36/50 infants were extubated within the first 28 days of life and 13/36 (36%) developed BPD. In the Ambroxol group 44/52 were extubated and 9/44 (20%) developed BPD. After extubation, RFT showed (i) no statistically significant difference in the ventilatory parameters of either treatment group, (ii) improved (P<0·05) lung mechanics (VT/maxPes) in Ambroxol group compared to controls (9·4±2·7 ml kPa−1vs. 8·1±2·6 ml kPa−1) and (iii) no statistically significant difference in lung function between infants with and without BPD. At day 28 we found (i) no effect of early Ambroxol treatment on lung functions, (ii) significantly (P<0·05) higher f (58·5±11·7 min−1vs. 49·7±10·1 min−1) and significantly (P<0·01) lower VT(9·6±1·9 ml vs. 12·3±2·7 ml) and VT/maxPes(8·9±2·6 ml kPa−1vs. 12·0±2·9 ml kPa−1) in infants with BPD compared to infants without and (iii) these differences are not influenced by early Ambroxol treatment.If the process of BPD development is induced, early Ambroxol treatment has no influence on impaired lung function at day 28

Die Mechanik und ihre Fachvertreter an der Universität Karlsruhe : Von den Anfängen bis an die Schwelle des 21. Jahrhunderts

Beschreibung der Mechanik und ihrer Fachvertreter an der Universität Karlsruhe von der Gründung 1825 als Polytechnische Schule bis in die aktuelle Gegenwart 2015 nach der Verschmelzung der Universität Karlsruhe (TH) und des Forschungszentrums Karlsruhe zum Karlsruher Institut für Technologie. Entwicklung der zugehörigen Fakultäten und der Mechanikinstitute. Biografien ausgewählter Professoren