384 research outputs found
Evaluation of a dry EEG system for application of passive brain-computer interfaces in autonomous driving
© 2017 Zander, Andreessen, Berg, Bleuel, Pawlitzki, Zawallich, Krol and Gramann. We tested the applicability and signal quality of a 16 channel dry electroencephalography (EEG) system in a laboratory environment and in a car under controlled, realistic conditions. The aim of our investigation was an estimation how well a passive Brain-Computer Interface (pBCI) can work in an autonomous driving scenario. The evaluation considered speed and accuracy of self-applicability by an untrained person, quality of recorded EEG data, shifts of electrode positions on the head after driving-related movements, usability, and complexity of the system as such and wearing comfort over time. An experiment was conducted inside and outside of a stationary vehicle with running engine, air-conditioning, and muted radio. Signal quality was sufficient for standard EEG analysis in the time and frequency domain as well as for the use in pBCIs. While the influence of vehicle-induced interferences to data quality was insignificant, driving-related movements led to strong shifts in electrode positions. In general, the EEG system used allowed for a fast self-applicability of cap and electrodes. The assessed usability of the system was still acceptable while the wearing comfort decreased strongly over time due to friction and pressure to the head. Fromthese results we conclude that the evaluated system should provide the essential requirements for an application in an autonomous driving context. Nevertheless, further refinement is suggested to reduce shifts of the system due to body movements and increase the headset’s usability and wearing comfort
Enhanced low-energy -decay strength of Ni and its robustness within the shell model
Neutron-capture reactions on very neutron-rich nuclei are essential for
heavy-element nucleosynthesis through the rapid neutron-capture process, now
shown to take place in neutron-star merger events. For these exotic nuclei,
radiative neutron capture is extremely sensitive to their -emission
probability at very low energies. In this work, we present
measurements of the -decay strength of Ni over the wide range
MeV. A significant enhancement is found in the
-decay strength for transitions with MeV. At present,
this is the most neutron-rich nucleus displaying this feature, proving that
this phenomenon is not restricted to stable nuclei. We have performed
-strength calculations within the quasiparticle time-blocking
approximation, which describe our data above MeV very well.
Moreover, large-scale shell-model calculations indicate an nature of the
low-energy strength. This turns out to be remarkably robust with
respect to the choice of interaction, truncation and model space, and we
predict its presence in the whole isotopic chain, in particular the
neutron-rich .Comment: 9 pages, 9 figure
Level densities and thermodynamical properties of Pt and Au isotopes
The nuclear level densities of Pt and Au below the
neutron separation energy have been measured using transfer and scattering
reactions. All the level density distributions follow the constant-temperature
description. Each group of isotopes is characterized by the same temperature
above the energy threshold corresponding to the breaking of the first Cooper
pair. A constant entropy excess and is observed in
Pt and Au with respect to Pt and Au,
respectively, giving information on the available single-particle level space
for the last unpaired valence neutron. The breaking of nucleon Cooper pairs is
revealed by sequential peaks in the microcanonical caloric curve
Completing the nuclear reaction puzzle of the nucleosynthesis of 92Mo
One of the greatest questions for modern physics to address is how elements
heavier than iron are created in extreme, astrophysical environments. A
particularly challenging part of that question is the creation of the so-called
p-nuclei, which are believed to be mainly produced in some types of supernovae.
The lack of needed nuclear data presents an obstacle in nailing down the
precise site and astrophysical conditions. In this work, we present for the
first time measurements on the nuclear level density and average strength
function of Mo. State-of-the-art p-process calculations systematically
underestimate the observed solar abundance of this isotope. Our data provide
stringent constraints on the NbMo reaction rate,
which is the last unmeasured reaction in the nucleosynthesis puzzle of
Mo. Based on our results, we conclude that the Mo abundance
anomaly is not due to the nuclear physics input to astrophysical model
calculations.Comment: Submitted to PR
Statistical properties of Pu, and Pu(n,) cross section calculation
The level density and gamma-ray strength function (gammaSF) of 243Pu have
been measured in the quasi-continuum using the Oslo method. Excited states in
243Pu were populated using the 242Pu(d,p) reaction. The level density closely
follows the constant-temperature level density formula for excitation energies
above the pairing gap. The gammaSF displays a double-humped resonance at low
energy as also seen in previous investigations of actinide isotopes. The
structure is interpreted as the scissors resonance and has a centroid of
omega_{SR}=2.42(5)MeV and a total strength of B_{SR}=10.1(15)mu_N^2, which is
in excellent agreement with sum-rule estimates. The measured level density and
gammaSF were used to calculate the 242Pu(n,gamma) cross section in a neutron
energy range for which there were previously no measured data.Comment: 9 pages, 8 figure
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