4,803 research outputs found
Domain formation in magnetic polymer composites: an approach via stochastic homogenization
We study the magnetic energy of magnetic polymer composite materials as the
average distance between magnetic particles vanishes. We model the position of
these particles in the polymeric matrix as a stochastic lattice scaled by a
small parameter and the magnets as classical spin
variables interacting via an Ising type energy. Under surface scaling of the
energy we prove, in terms of -convergence that, up to subsequences, the
(continuum) -limit of these energies is finite on the set of
Caccioppoli partitions representing the magnetic Weiss domains where it has a
local integral structure. Assuming stationarity of the stochastic lattice, we
can make use of ergodic theory to further show that the -limit exists
and that the integrand is given by an asymptotic homogenization formula which
becomes deterministic if the lattice is ergodic.Comment: 31 page
Seasonal changes in energy expenditure, body temperature and activity patterns in llamas (Lama glama)
The authors thank Knut Salzmann und Arne Oppermann for technical help and for taking care of the animals and Anna Stölzl for help with the administering of the ruminal unit of the telemetry system. The study was supported by a grant from the German Research Foundation (DFG) to A.R. (RI 1796/3-1).Peer reviewedPublisher PD
Pengembagan Lembar Kerja Siswa Berbasis Kontekstual untuk Membentuk Literasi Sains pada Pembelajaran Fisika Materi Listrik Dinamis Kelas IX SMP
The aim of this research is to produce student worksheet based on contextual to form science literacy that valid. Benefits of this research is the product can be used as teaching material teacher guide, increaseknowledge of science , guiding students in self-development as well as providing literacy skills of science and students\u27 critical thinking skills. The research method used is Research and Development (R & D). Method steps include potentials and problems, literature and information review, product design, validation, and proven design. The result of the research shows the validity of LKS stucture is 100% with High category. In the validity of the contents of the LKS done twice with the results of the first validation of 76, 83% with high category but not valid because there are still indicators Low category. After making the improvement, the second validation result is 80.08% with High category. The Student Worksheet is declared valid and suitable for use by the school as a teaching material and is recommended to continue the research in the form of application as a trial to the school with the manufacture of mass products
Status of Axisymmetric CFD of an Eleven Inch Diameter Hybrid Rocket Motor
Current status of a steady state, axisymmetric analysis of an experimental 11 inch diameter hybrid rocket motor internal flow field is given. The objective of this effort is to develop a steady state axisymmetric model of the 11 inch hybrid rocket motor which can be used as a design and/or analytical tool. A test hardware description, modeling approach, and future plans are given. The analysis was performed with FDNS implementing several finite rate chemistry sets. A converged solution for a two equation and five species set on a 'fine' grid is shown
Bestimmung von Uran in Mineralen durch zerstoerungsfreie Neutronenaktivierungsanalyse ueber U-239
Trennung von Natrium, Caesium und Barium mittels eines Anionenaustauschers und saeurehaltiger waessrig-organischer Solvensmischungen
Aquarius Radiometer Performance: Early On-Orbit Calibration and Results
The Aquarius/SAC-D observatory was launched into a 657-km altitude, 6-PM ascending node, sun-synchronous polar orbit from Vandenberg, California, USA on June 10, 2011. The Aquarius instrument was commissioned two months after launch and began operating in mission mode August 25. The Aquarius radiometer meets all engineering requirements, exhibited initial calibration biases within expected error bars, and continues to operate well. A review of the instrument design, discussion of early on-orbit performance and calibration assessment, and investigation of an on-going calibration drift are summarized in this abstract
Pair production in laser fields oscillating in space and time
The production of electron-positron pairs from vacuum by counterpropagating
laser beams of linear polarization is calculated. In contrast to the usual
approximate approach, the spatial dependence and magnetic component of the
laser field are taken into account. We show that the latter strongly affects
the creation process at high laser frequency: the production probability is
reduced, the kinematics is fundamentally modified, the resonant
Rabi-oscillation pattern is distorted and the resonance positions are shifted,
multiplied and split.Comment: 5 pages, 5 figure
Proposal to Search for Heavy Neutral Leptons at the SPS
A new fixed-target experiment at the CERN SPS accelerator is proposed that
will use decays of charm mesons to search for Heavy Neutral Leptons (HNLs),
which are right-handed partners of the Standard Model neutrinos. The existence
of such particles is strongly motivated by theory, as they can simultaneously
explain the baryon asymmetry of the Universe, account for the pattern of
neutrino masses and oscillations and provide a Dark Matter candidate.
Cosmological constraints on the properties of HNLs now indicate that the
majority of the interesting parameter space for such particles was beyond the
reach of the previous searches at the PS191, BEBC, CHARM, CCFR and NuTeV
experiments. For HNLs with mass below 2 GeV, the proposed experiment will
improve on the sensitivity of previous searches by four orders of magnitude and
will cover a major fraction of the parameter space favoured by theoretical
models.
The experiment requires a 400 GeV proton beam from the SPS with a total of
2x10^20 protons on target, achievable within five years of data taking. The
proposed detector will reconstruct exclusive HNL decays and measure the HNL
mass. The apparatus is based on existing technologies and consists of a target,
a hadron absorber, a muon shield, a decay volume and two magnetic
spectrometers, each of which has a 0.5 Tm magnet, a calorimeter and a muon
detector. The detector has a total length of about 100 m with a 5 m diameter.
The complete experimental set-up could be accommodated in CERN's North Area.
The discovery of a HNL would have a great impact on our understanding of
nature and open a new area for future research
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