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 $\varepsilon$ and the magnets as classical $\pm 1$ spin variables interacting via an Ising type energy. Under surface scaling of the energy we prove, in terms of $\Gamma$-convergence that, up to subsequences, the (continuum) $\Gamma$-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 $\Gamma$-limit exists and that the integrand is given by an asymptotic homogenization formula which becomes deterministic if the lattice is ergodic.Comment: 31 page

Absorptive Effects and Classical Black Hole Scattering

We describe an approach to incorporating the physical effects of the absorption of energy by the event horizon of black holes in the scattering amplitudes based post-Minkowskian, point-particle effective description. Absorptive dynamics are incorporated in a model-independent way by coupling the usual point-particle description to an invisible sector of gapless internal degrees-of-freedom. The leading order dynamics of this sector are encoded in the low-energy expansion of a spectral density function obtained by matching an absorption cross section in the ultraviolet description. This information is then recycled using the scattering amplitudes based Kosower-Maybee-O'Connell in-in formalism to calculate the leading absorptive contribution to the impulse and change in rest mass of a Schwarzschild black hole scattering with a second compact body sourcing a massless scalar, electromagnetic or gravitational field. The results obtained are in complete agreement with previous worldline Schwinger-Keldysh calculations and provide an alternative on-shell scattering amplitudes approach to incorporating horizon absorption effects in the gravitational two-body problem.Comment: 36 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

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