Low-Complexity Decentralized Active Damping of One-Dimensional Structures

In the paper, we propose distributed feedback control laws for active damping of one-dimensional mechanical structures equipped with dense arrays of force actuators and position and velocity sensors. We consider proportional position and velocity feedback from the neighboring nodes with symmetric gains. Achievable control performance with respect to stability margin and damping ratio is discussed. Compared to full-featured complex controllers obtained by modern design methods like LQG, H-infinity, or mu-synthesis, these simplistic controllers are more suitable for experimental fine tuning and are less case-dependent, and they shall be easier to implement on the target future smart-material platforms

Long-Term Cold Acclimation Extends Survival Time at 0°C and Modifies the Metabolomic Profiles of the Larvae of the Fruit Fly Drosophila melanogaster

Drosophila melanogaster is a chill-susceptible insect. Previous studies on this fly focused on acute direct chilling injury during cold shock and showed that lower lethal temperature (LLT, approximately -5°C) exhibits relatively low plasticity and that acclimations, both rapid cold hardening (RCH) and long-term cold acclimation, shift the LLT by only a few degrees at the maximum.We found that long-term cold acclimation considerably improved cold tolerance in fully grown third-instar larvae of D. melanogaster. A comparison of the larvae acclimated at constant 25°C with those acclimated at constant 15°C followed by constant 6°C for 2 d (15°C→6°C) showed that long-term cold acclimation extended the lethal time for 50% of the population (Lt(50)) during exposure to constant 0°C as much as 630-fold (from 0.137 h to 86.658 h). Such marked physiological plasticity in Lt(50) (in contrast to LLT) suggested that chronic indirect chilling injury at 0°C differs from that caused by cold shock. Long-term cold acclimation modified the metabolomic profiles of the larvae. Accumulations of proline (up to 17.7 mM) and trehalose (up to 36.5 mM) were the two most prominent responses. In addition, restructuring of the glycerophospholipid composition of biological membranes was observed. The relative proportion of glycerophosphoethanolamines (especially those with linoleic acid at the sn-2 position) increased at the expense of glycerophosphocholines.Third-instar larvae of D. melanogaster improved their cold tolerance in response to long-term cold acclimation and showed metabolic potential for the accumulation of proline and trehalose and for membrane restructuring

Methode zur direkten Methylierung dünnschichtchromatographisch aufgetrennter Lipide ohne deren Elution aus Kieselgel

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Minutenschnelle Verseifung von Lipiden bei Raumtemperatur

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Relation between Current Transfer Length and Stability of Fe/MgB2MgB_2 and Fe/Nb/MgB2MgB_2 Conductors

This paper treats and confronts the stability of two different composite $MgB_2$ superconductors and searches for relation between the current transfer length and maximum heat flux that conductor can withstand in operational DC regime. It was found that the iron sheathed wire behave more stably than tape-like conductor with outer iron sheath and inner niobium barrier

Properties of doped ex and in situ MgB2 multifilament superconductors

7 pages, 11 figures, 1 table.Four-filament ex and in situ MgB2 wires were prepared with the rectangular wire-in-tube (RWIT) technique. Based on experience with single-core wires, 10 wt% of W was added to the ex situ and 10 wt% of SiC to the in situ powders, which were packed into Fe and Nb/AgMg tubes, respectively, and two-axially rolled into composite conductors. The ex and in situ conductors are compared in terms of field-dependent transport critical current density, effects of filament size reduction and twisting, mechanical behaviour and thermal stability.This work was supported by the Science and Technology Assistance Agency under the contract number APVT-51-029902, and by the EU FP6 contract number NMP3-CT2004-505724. Authors would like to thank T Holúbek for the I–V characteristic measurements.Peer reviewe