1,153 research outputs found
Horizontal rotation signals detected by "G-Pisa" ring laser for the Mw=9.0, March 2011, Japan earthquake
We report the observation of the ground rotation induced by the Mw=9.0, 11th
of March 2011, Japan earthquake. The rotation measurements have been conducted
with a ring laser gyroscope operating in a vertical plane, thus detecting
rotations around the horizontal axis. Comparison of ground rotations with
vertical accelerations from a co-located force-balance accelerometer shows
excellent ring laser coupling at periods longer than 100s. Under the plane wave
assumption, we derive a theoretical relationship between horizontal rotation
and vertical acceleration for Rayleigh waves. Due to the oblique mounting of
the gyroscope with respect to the wave direction-of-arrival, apparent
velocities derived from the acceleration / rotation rate ratio are expected to
be always larger than, or equal to the true wave propagation velocity. This
hypothesis is confirmed through comparison with fundamental-mode, Rayleigh wave
phase velocities predicted for a standard Earth model.Comment: Accepted for publication in Journal of Seismolog
Influence of Mandrel s Surface on the Mechanical Properties of Joints Produced by Electromagnetic Compression
Electromagnetic compression of tubular profiles with high electrical conductivity is an innovative joining process for the manufacturing of lightweight structures. Taking conventional interference fits into account, the contact area s influence on the joint s quality seems to be of significance, as e.g. the contact area and the friction coefficient between the joining partners determine an allowed axial load or torsional momentum proportionally. Therefore, different contact area surfaces were prepared by shot peening and different machining operations and strategies. The mandrel s surfaces were prepared by shot peening with glass beads and Al2O3 particles. Alternatively, preparation was done using simultaneous five axis milling, because potential joining partners in lightweight frame structures within the Transregional Collaborative Research Centre SFB/TR10 would be manufactured similarly. After that, the manufactured surfaces were characterized by measuring the surface roughness and using confocal whitelight microscopy. After joining by electromagnetic compression, the influence of different mandrel s surface conditions on the joint s mechanical properties were analyzed by tensile tests. Finally, conclusions and design rules for the manufacturing of joints by electromagnetic compression are given
Beam Test of Silicon Strip Sensors for the ZEUS Micro Vertex Detector
For the HERA upgrade, the ZEUS experiment has designed and installed a high
precision Micro Vertex Detector (MVD) using single sided micro-strip sensors
with capacitive charge division. The sensors have a readout pitch of 120
microns, with five intermediate strips (20 micron strip pitch). An extensive
test program has been carried out at the DESY-II testbeam facility. In this
paper we describe the setup developed to test the ZEUS MVD sensors and the
results obtained on both irradiated and non-irradiated single sided micro-strip
detectors with rectangular and trapezoidal geometries. The performances of the
sensors coupled to the readout electronics (HELIX chip, version 2.2) have been
studied in detail, achieving a good description by a Monte Carlo simulation.
Measurements of the position resolution as a function of the angle of incidence
are presented, focusing in particular on the comparison between standard and
newly developed reconstruction algorithms.Comment: 41 pages, 21 figures, 2 tables, accepted for publication in NIM
A translational research experience in Argentina.
Background: The Argentinean programwas initiatedmore than a decade ago as the first experience of systematic
translational research focused on NCL in Latin America. The aim was to overcome misdiagnoses and
underdiagnoses in the region.
Subjects: 216 NCL suspected individuals from 8 different countries and their direct family members.
Methods: Clinical assessment, enzyme testing, electron microscopy, and DNA screening.
Results and discussion: 1) The study confirmed NCL disease in 122 subjects. Phenotypic studies comprised
epileptic seizures and movement disorders, ophthalmology, neurophysiology, image analysis, rating scales,
enzyme testing, and electron microscopy, carried out under a consensus algorithm; 2) DNA screening and
validation of mutations in genes PPT1 (CLN1), TPP1 (CLN2), CLN3, CLN5, CLN6, MFSD8 (CLN7), and CLN8:
characterization of variant types, novel/knownmutations and polymorphisms; 3) Progress of the epidemiological
picture in Latin America; and 4) NCL-like pathology studies in progress. The Translational Research Program was
highly efficient in addressing the misdiagnosis/underdiagnosis in the NCL disorders. The study of “orphan
diseases” in a public administrated hospital should be adopted by the health systems, as it positively impacts
upon the family's quality of life, the collection of epidemiological data, and triggers research advances. This article
is part of a Special Issue entitled: “Current Research on the Neuronal Ceroid Lipofuscinoses (Batten Disease)”publishedVersio
Uma Metodologia para o Desenvolvimento de Ontologias
Ontologias são um importante meio de representar, formalizar e compartilhar conhecimento. No contexto da Engenharia de Ontologias, várias metodologias de desenvolvimento são propostas, cada qual com suas características em relação ao ciclo de vida de ontologias. Por conseguinte, não há uma metodologia estabelecida como padrão para o propósito geral de desenvolvimento de ontologias. Por isso, na literatura acadêmica enfatiza-se a combinação de metodologias. Mediante o estudo de algumas metodologias, atentando as características de simplicidade, expressividade e funcionalidade, é abstraído um conjunto de elementos para o desenvolvimento de ontologias. Como resultado, tem-se uma nova metodologia, a qual compreende as atividades, as tarefas e a sugestão de ferramentas em um processo de desenvolvimento de ontologias, sendo que tal metodologia foi validada em pesquisas exploratórias e/ou aplicadas
The wavefront of the radio signal emitted by cosmic ray air showers
Analyzing measurements of the LOPES antenna array together with corresponding
CoREAS simulations for more than 300 measured events with energy above
eV and zenith angles smaller than , we find that the radio
wavefront of cosmic-ray air showers is of approximately hyperbolic shape. The
simulations predict a slightly steeper wavefront towards East than towards
West, but this asymmetry is negligible against the measurement uncertainties of
LOPES. At axis distances m, the wavefront can be approximated by
a simple cone. According to the simulations, the cone angle is clearly
correlated with the shower maximum. Thus, we confirm earlier predictions that
arrival time measurements can be used to study the longitudinal shower
development, but now using a realistic wavefront. Moreover, we show that the
hyperbolic wavefront is compatible with our measurement, and we present several
experimental indications that the cone angle is indeed sensitive to the shower
development. Consequently, the wavefront can be used to statistically study the
primary composition of ultra-high energy cosmic rays. At LOPES, the
experimentally achieved precision for the shower maximum is limited by
measurement uncertainties to approximately g/cm. But the simulations
indicate that under better conditions this method might yield an accuracy for
the atmospheric depth of the shower maximum, , better than
g/cm. This would be competitive with the established air-fluorescence
and air-Cherenkov techniques, where the radio technique offers the advantage of
a significantly higher duty-cycle. Finally, the hyperbolic wavefront can be
used to reconstruct the shower geometry more accurately, which potentially
allows a better reconstruction of all other shower parameters, too.Comment: accepted by JCA
- …