185 research outputs found
Cryogenic interferometric inertial sensors for penultimate mirror vibration monitoring
No full textThe poster aims to present highly sensitive inertial sensors developed for future gravitational-wave detectors. E-TEST (Einstein Telescope Euregio Meuse-Rhine Site & Technology)[1,2] is an international collaboration that consists of a prototype suspension combining passive and active isolation techniques for a 100 kg silicon mirror cooled down radiatively to 25 K in a suspended cryostat. It is aimed at validating R&D to meet Einstein Telescope’s requirements in the relevant environment [3]. This unprecedented seismic isolation calls for highly sensitive inertial sensors at each stage of the isolation chain to monitor its efficiency, as well as the performance of the low-vibration cooling strategy by characterizing the residual motion at the mirror level. Several sensors have been developed either as part of the isolation stage of the suspension or as witness sensors in the harsh cryogenic environment close to the mirror. Cryogenic and vacuum compatible horizontal and vertical cryogenic inertial sensors were developed to monitor the cryogenic penultimate stage down to 1 fm/√Hz from 1 Hz onwards. [1] A. Sider, C. D. Fronzo, L. Amez-Droz, A. Amorosi, F. Badaracco, P. Baer, A. Bertolini, G. Bruno, P. Cebeci, C. Collette, et al., Classical and Quantum Gravity 40, 165002 (2023), URL https://dx.doi.org/10.1088/1361-6382/ace230 [2] A. Sider, L. Amez-Droz, A. Amorosi, F. Badaracco, P. Baer, G. Bruno, A. Bertolini, C. Collette, P. Cebeci, C. D. Fronzo, et al., E-test prototype design report (2022), 2212.10083. [3] S. Di Pace, V. Mangano, L. Pierini, A. Rezaei, J.-S. Hennig, M. Hennig, D. Pascucci, A. Allocca, I. Tosta e Melo, V. G. Nair, et al., Galaxies 10 (2022), ISSN 2075-4434, URL https://doi.org/10.3390/galaxies10030065Stella
Parasitic copepods from Egyptian Red Sea fishes: Bomolochidae Claus, 1875
No full text© The Author(s) 2015
Open Access - This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The attached file is the published version of the article.NHM Repositor
A Consistency Analysis of Phase-Locked-Loop Testing and Control-Based Continuation for a Geometrically Nonlinear Frictional System
No full textpeer reviewedTwo of the most popular vibration testing methods for nonlinear structures are control-based continuation and phase-locked-loop testing. In this paper, they are directly compared on the same benchmark system, for the first time, to demonstrate their general capabilities and to discuss practical implementation aspects. The considered system, which is specifically designed for this study, is a slightly arched beam clamped at both ends via bolted joints. It exhibits a pronounced softening-hardening behavior as well as an increasing damping characteristic due to the frictional clamping. Both methods are implemented to identify periodic responses at steady-state constituting the phase-resonant backbone curve and nonlinear frequency response curves. To ensure coherent results, the repetition variability is thoroughly assessed via an uncertainty analysis. It is concluded that the methods are in excellent agreement, taking into account the inherent repetition variability of the system
Reading acts of narrative appropriation: four instances of fraudulent memoir
No full textPhDThis thesis examines acts of narrative appropriation, the telling of purportedly‘authentic’ life stories by those for whom the stories are not theirs to tell. This
misuse or subversion of genre - the discipline of historical writing and the category
of autobiography - becomes a means for cultural, social and political dissimulation,
and the analysis focuses both on the act: the event, trespass, or ‘theft’ of another’s
life story, and on the cultural meaning that this event reveals. These narrative acts
are approached theoretically through discussions of what it means to be an author, a
reader, and through the consideration of literary and social genre, category and form.
In exploring identities at particular risk of appropriation, this thesis shows how
fraudulent appropriated narratives affect our reading of the world, and in turn
influence our perception of already marginalized social groups. My primary
examples include prostitution ‘narratives’, Native North American ‘memoir,’ and
fraudulent Holocaust survivor ‘testimony,’ with each text providing decoded
evidence of ‘genre-bending’ exhibiting a social and political intent. These works
seek to be read as authentic personal narratives, as autobiography, and that is how
they have been presented to the reader. However, they are imposters – fictional tales
desiring the elevated status of historical authenticity and willing to bend the rules
and contracts of genre to achieve their end. Here the appearance of authenticity is
achieved through the use of cultural and social ‘myth,’ or perceptions of cultural
identity, and as such its fraudulent construction is first and foremost a social act,
with a social and economic motivation. As this thesis concludes, these texts are
most successful when their own political and social ideologies echo and confirm that
of the readership; when their subjects, the fraudulent ‘I’ at the center of the text is
also a performative elaboration of cultural belief
On magnetorheologic elastomers for vibration isolation, damping, and stress reduction in mass-varying structures
No full textThis article considers two devices based on a magnetorheological elastomer (MRE): an MRE isolator under a frequency-varying harmonic excitation and a MRE Dynamic Vibration Absorber (DVA) mounted on a frequency-varying structure under a random excitation. In the first case, it is shown that the commandability of the elastomer improves the reduction of the RMS value of the body displacement by 10%. In the second case, it is shown on a simple example that a MRE DVA, while not optimal, can reduce the stress in the structure about 50% better than a classical DVA when the mass of the structure changes 35%. This makes them suitable to avoid high stress in mass-varying structures, and delay some damage mechanisms like the emergence of cracks and fatigue. © 2010 The Author(s).SCOPUS: cp.jinfo:eu-repo/semantics/publishe
Local modulation of human brain responses by circadian rhythmicity and sleep debt
No full textpeer reviewe
Age-related decrease in cortical excitability circadian variations during sleep loss and its links with cognition
No full textpeer reviewe
Constraining the p-Mode–g-Mode tidal instability with GW170817
No full textWe analyze the impact of a proposed tidal instability coupling p modes and g modes within neutron stars on GW170817. This nonresonant instability transfers energy from the orbit of the binary to internal modes of the stars, accelerating the gravitational-wave driven inspiral. We model the impact of this instability on the phasing of the gravitational wave signal using three parameters per star: an overall amplitude, a saturation frequency, and a spectral index. Incorporating these additional parameters, we compute the Bayes factor (ln B pg !pg) comparing our p-g model to a standard one. We find that the observed signal is consistent with waveform models that neglect p-g effects, with ln B pg !pg = 0.03 +0.70 -0.58 (maximum a posteriori and 90% credible region). By injecting simulated signals that do not include p-g effects and recovering them with the p-g model, we show that there is a ?50% probability of obtaining similar ln B pg !pg even when p-g effects are absent. We find that the p-g amplitude for 1.4 ?M? neutron stars is constrained to less than a few tenths of the theoretical maximum, with maxima a posteriori near one-tenth this maximum and p-g saturation frequency ~70 Hz. This suggests that there are less than a few hundred excited modes, assuming they all saturate by wave breaking. For comparison, theoretical upper bounds suggest ?103 modes saturate by wave breaking. Thus, the measured constraints only rule out extreme values of the p-g parameters. They also imply that the instability dissipates ?10^51 erg over the entire inspiral, i.e., less than a few percent of the energy radiated as gravitational waves
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