ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Berechnung der Wirbelstromdichten und-kräfte in der Umgebung großer supraleitender Spulen für den magnetischen Einschluß bei der Kernfusion (1995)
    Springer
    Electrical engineering 78 (1995), S. 223-228 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents The reliable operation of the superconducting magnet systems used for the magnetic confinement in nuclear fusion research requires the ability of a fast discharge of the stored magnetic energy. The corresponding magnetic field variation gives rise to high eddy currents by inductive coupling with surrounding conductive components. The eddy current forces can lead to a mechanical overload of some of these components. A simple numerical-analytical method was developed in order to calculate these forces. This method is presented and compared with the Finite Element Method.
    Notes: Übersicht Um die Betriebssicherheit großer supraleitender Magnetsysteme für die Kernfusionsforschung zu gewährleisten, muß die im Magnetsystem gespeicherte Energie schnell entladen werden können. Durch die veränderlichen großvolumigen Magnetfelder werden in benachbarten leitfähigen Strukturen durch Induktion hohe Wirbelströme hervorgerufen. Durch sie treten dort elektromagnetische Kräfte. auf, die einzelne Komponenten mechanisch überlasten können. Zur Berechnung dieser Kräfte wurde eine einfache numerischanalytische Methode entwickelt, die im folgenden vorgestellt und mit Finite-Elemente-Verfahren verglichen wird.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01240226
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Plastic deformation of polyethylene and ethylene copolymers: Part I Homogeneous crystal slip and molecular mobility (1998)
    Springer
    Journal of materials science 33 (1998), S. 1273-1279 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The plastic behaviour of polyethylene and ethylene copolymers is studied under uniaxial tensile testing in parallel with the viscoelastic properties. Homogeneous plastic deformation is shown to take place at temperatures above the crystalline mechanical relaxation. The activation of homogeneous crystal slip is discussed in relation to the crystal lamella thickness and the molecular mobility of the crystalline chain stems. The thermally activated process of nucleation and propagation of screw dislocations that is proposed for the mechanism of the homogeneous crystal slip relies on the generation of 180° chain twists in the crystal stems of the sheared crystals. This kind of conformational chain defect is the basic link between the plastic and the viscoelastic properties of the materials. Homogeneous crystal slip can take place as long as the applied strain rate is consistent with the strain rate affordable by the screw dislocation propagation. The dependence on draw temperature of the crystal thickness in the fibre structure is ascribed to the stress-induced activation of 180° chain twists which allows an adjustment of the crystal thickness to the temperature of the experiment faster than an annealing treatment will. © 1998 Chapman & Hall
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004342113141
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Water response of the hygrochastic skeletons of the true rose of Jericho (Anastatica hierochuntica L.) (1978)
    Springer
    Oecologia 32 (1978), S. 289-301 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The hygrochastic apparatus in Anastatica hierochuntica was investigated from the standpoint of morphology of the skeleton and fruit and its contribution to the regulation of seed dispersal in accordance with the water conditions. Water absorption by the dry skeletons upon shoot immersion under laboratory conditions is a rapid process requiring only a few minutes. It is followed by a slow opening of the curled branches of the skeleton. Maximal opening is attained by the saturated skeletons in approximately 2h. Absorption of water and subsequent opening occur also when only the main root of the skeleton is immersed in water. The process was duplicated also by intact skeletons irrigated in situ. Skeletons closure in response to evaporation is initially slow, noticable curling of the branches obtained only after 60% of the water is lost from the saturated skeletons. Opening of the skeleton exposes most of the fruits to the force of falling raindrops. The fact that no spontaneous opening of fruits occurred under most laboratory procedures of skeleton immersion suggests that in nature two successive processes occur: the skeletons must first uncurl-hygrochasticly so that raindrops can impinge forcefully on the appendages of the fruit valves and thus cause seed release by ombrohydrochory. Under adequate rainfall, the first fruits to open are those at the outer infructescences; heavier rainfall will release seeds from the upper fruits of the inner infructescences, and later, from fruits at their bases. The force that binds the valves of the fruits to the septa is variable, its strength correlated with different structure of the fruist at different positions on the skeleton. This ensures a rate of seed release commensurate with the rainfall, and secures at least a minimum of water for the first seeds. The heterogeneity of skeleton populations insofar as age of the plants is concerned, further ensures that seed dispersal in a given area will be proportional to the amount of rainfall.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00345108
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Modeling and Realization of n-Dimensional Linear Discrete Systems (1998)
    Springer
    Multidimensional systems and signal processing 9 (1998), S. 241-253 
    Details
    ISSN: 1573-0824
    Keywords: behaviours ; n-D linear systems ; AR representations ; ARMA representations ; minimality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Using a general model for multidimensional linear discrete systems, a new non-minimal real ARMA realization is given for n-dimensional systems in AR forms. A definition of minimality which is compatible with both the underlying theory and its engineering applications, and some necessary conditions for minimality of multidimensional systems are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008276619008
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Plastic deformation of polyethylene and ethylene copolymers: Part II Heterogeneous crystal slip and strain-induced phase change (1998)
    Springer
    Journal of materials science 33 (1998), S. 1801-1807 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The plastic behaviour of polyethylene and ethylene copolymers is studied under uniaxial tensile testing with particular attention to the development of plastic instability. Heterogeneous crystal slip is suggested to take place when homogeneous crystal slip either is not allowed at the temperature and strain rate of the experiment or is exhausted owing to extension of the chain folds. The chain unfolding concomitant to the fragmentation of the crystalline lamellae is suspected to have a low strain hardening that is responsible for the phenomenon. Partial screw dislocations with a shorter Burgers vector than in the case of homogeneous slip are proposed to become operative because of the activation of 90 ° chain twists in the crystalline stems. Dissociation of dislocations into partials involves stacking faults in the orthorhombic structure that may turn into monoclinic structure through a martensitic-like transformation. Crystal slip is likely to concentrate in these faulty regions owing to the reduced molecular interactions and lower density. Two types of correspondence of the transformed monoclinic phase with the parent orthorhombic structure are observed. The modification of the chain-folding macroconformation as a function of the crystallinity of the materials is suspected to influence the transformation shear mode. © 1998 Chapman & Hall
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004340902180
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    facet.materialart.
    Unknown
    Infection of phytoplankton by aerosolized marine viruses (2015)
    National Academy of Sciences
    Details
    Publication Date: 2015-05-11
    Description: Marine viruses constitute a major ecological and evolutionary driving force in the marine ecosystems. However, their dispersal mechanisms remain underexplored. Here we follow the dynamics ofEmiliania huxleyiviruses (EhV) that infect the ubiquitous, bloom-forming phytoplanktonE. huxleyiand show thatEhV are emitted to the atmosphere as primary marine aerosols. Using a laboratory-based setup, we showed that the dynamic ofEhV aerial emission is strongly coupled to the host–virus dynamic in the culture media. In addition, we recoveredEhV DNA from atmospheric samples collected over anE. huxleyibloom in the North Atlantic, providing evidence for aerosolization of marine viruses in their natural environment. Decay rate analysis in the laboratory revealed that aerosolized viruses can remain infective under meteorological conditions prevailing duringE. huxleyiblooms in the ocean, allowing potential dispersal and infectivity over hundreds of kilometers. Based on the combined laboratory and in situ findings, we propose that atmospheric transport ofEhV is an effective transmission mechanism for spreading viral infection over large areas in the ocean. This transmission mechanism may also have an important ecological impact on the large-scale host–virus “arms race” during bloom succession and consequently the turnover of carbon in the ocean.
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 7
    facet.materialart.
    Unknown
    Endocytosis as a stabilizing mechanism for tissue homeostasis (2018)
    National Academy of Sciences
    Details
    Publication Date: 2018-02-02
    Description: Cells in tissues communicate by secreted growth factors (GF) and other signals. An important function of cell circuits is tissue homeostasis: maintaining proper balance between the amounts of different cell types. Homeostasis requires negative feedback on the GFs, to avoid a runaway situation in which cells stimulate each other and grow without control. Feedback can be obtained in at least two ways: endocytosis in which a cell removes its cognate GF by internalization and cross-inhibition in which a GF down-regulates the production of another GF. Here we ask whether there are design principles for cell circuits to achieve tissue homeostasis. We develop an analytically solvable framework for circuits with multiple cell types and find that feedback by endocytosis is far more robust to parameter variation and has faster responses than cross-inhibition. Endocytosis, which is found ubiquitously across tissues, can even provide homeostasis to three and four communicating cell types. These design principles form a conceptual basis for how tissues maintain a healthy balance of cell types and how balance may be disrupted in diseases such as degeneration and fibrosis.
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 8
    facet.materialart.
    Unknown
    Structural insights into species-specific features of the ribosome from the pathogen Staphylococcus aureus (2015)
    National Academy of Sciences
    Details
    Publication Date: 2015-10-13
    Description: The emergence of bacterial multidrug resistance to antibiotics threatens to cause regression to the preantibiotic era. Here we present the crystal structure of the large ribosomal subunit from Staphylococcus aureus, a versatile Gram-positive aggressive pathogen, and its complexes with the known antibiotics linezolid and telithromycin, as well as with a new, highly potent pleuromutilin derivative, BC-3205. These crystal structures shed light on specific structural motifs of the S. aureus ribosome and the binding modes of the aforementioned antibiotics. Moreover, by analyzing the ribosome structure and comparing it with those of nonpathogenic bacterial models, we identified some unique internal and peripheral structural motifs that may be potential candidates for improving known antibiotics and for use in the design of selective antibiotic drugs against S. aureus.
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 9
    facet.materialart.
    Unknown
    All-trans-retinal shuts down rod cyclic nucleotide-gated ion channels: A novel role for photoreceptor retinoids in the response to bright light? (2002)
    National Academy of Sciences
    Details
    Publication Date: 2002-05-28
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    Possible cooption of a VEGF-driven tubulogenesis program for biomineralization in echinoderms (2019)
    National Academy of Sciences
    Details
    Publication Date: 2019-05-31
    Description: Biomineralization is the process by which living organisms use minerals to form hard structures that protect and support them. Biomineralization is believed to have evolved rapidly and independently in different phyla utilizing preexisting components. The mechanistic understanding of the regulatory networks that drive biomineralization and their evolution is far from clear. Sea urchin skeletogenesis is an excellent model system for studying both gene regulation and mineral uptake and deposition. The sea urchin calcite spicules are formed within a tubular cavity generated by the skeletogenic cells controlled by vascular endothelial growth factor (VEGF) signaling. The VEGF pathway is essential for biomineralization in echinoderms, while in many other phyla, across metazoans, it controls tubulogenesis and vascularization. Despite the critical role of VEGF signaling in sea urchin spiculogenesis, the downstream program it activates was largely unknown. Here we study the cellular and molecular machinery activated by the VEGF pathway during sea urchin spiculogenesis and reveal multiple parallels to the regulation of vertebrate vascularization. Human VEGF rescues sea urchin VEGF knockdown, vesicle deposition into an internal cavity plays a significant role in both systems, and sea urchin VEGF signaling activates hundreds of genes, including biomineralization and interestingly, vascularization genes. Moreover, five upstream transcription factors and three signaling genes that drive spiculogenesis are homologous to vertebrate factors that control vascularization. Overall, our findings suggest that sea urchin spiculogenesis and vertebrate vascularization diverged from a common ancestral tubulogenesis program, broadly adapted for vascularization and specifically coopted for biomineralization in the echinoderm phylum.
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...