A quasilinear transmission problem with application to Maxwell equations with a divergence-free D-field

Maxwell equations in the absence of free charges require initial data with a divergence-free displacement field D. In materials in which the dependence D=D(E) is nonlinear the quasilinear problem 07 c5D(E)=0 is hence to be solved. In many applications, e.g. in the modelling of wave packets, an approximative asymptotic ansatz of the electric field E is used, which satisfies this divergence condition at t=0 only up to a small residual. We search then for a small correction of the ansatz to enforce 07 c5D(E)=0 at t=0 and choose this correction in the form of a gradient field. In the usual case of a power type nonlinearity in D(E) this leads to the sum of the Laplace and p-Laplace operators. We also allow for the medium to consist of two different materials so that a transmission problem across an interface is produced. We prove the existence of the correction term for a general class of nonlinearities and provide regularity estimates for its derivatives, independent of the L2-norm of the original ansatz. In this way, when applied to the wave packet setting, the correction term is indeed asymptotically smaller than the original ansatz. We also provide numerical experiments to support our analysis

Li distribution in the ionic conductor Li1+xAlxTi2-x(PO4)3 with 0 ≤ x ≤ 0.6 studied by neutron diffraction

Li1+xAlxTi2-xP3O12 (LATP) is among the most widely investigated solid electrolyte materials for Li ion batteries because of its relatively high ionic conductivity, chemical stability and mechanical strength. Its ionic conductivity is induced by partial substitution of Ti with Al, in combination with the incorporation of additional Li ions into the structure. The electrical conductivity therefore depends strongly on the substitution parameter x. A series of Li1+xAlxTi2-x(PO4)3 powders with 0 ≤ x ≤ 0.6 were prepared by two different syntheses routes, a) solid state reaction and b) a novel sol-gel method leading to high phase purity, densification activity and conductivity. The highest ionic conductivity of 1.0 × 10-3 S cm-1 at 25 °C was obtained for Li1.5Al0.5Ti1.5(PO4)3 with nearly theoretical density. We have studied the distribution of Li ions in this series by neutron diffraction analysis at different temperatures. The refinements revealed that excess Li ions are scattered throughout the crystal structure at temperatures above 600 K, making it difficult to precisely determine Li positions and non-stoichiometry. At low temperatures Li ions may occupy a set of different positions, namely the 6a site identified in our previous study or the 18e and 36f sites discussed in the literature [1-3]. A correlation between the synthesis method and the location of Li ions was observed, which is consistent with the ionic conductivity of these materials. [1] E. Dashjav, F. Tietz, Z. Anorg. Allg. Chem., 2014, 640, 15, 3070 [2] D. Tran Qui, S. Hamdoune, J. L. Soubeyroux, E. Prince, J. Solid State Chem. 1988, 72, 309 [3] M. Catti, A. Comotti, S. di Blas, R. M. Ibberson, J. Mater. Chem., 2004, 14, 83

A preliminary experiment definition for video landmark acquisition and tracking

Six scientific objectives/experiments were derived which consisted of agriculture/forestry/range resources, land use, geology/mineral resources, water resources, marine resources and environmental surveys. Computer calculations were then made of the spectral radiance signature of each of 25 candidate targets as seen by a satellite sensor system. An imaging system capable of recognizing, acquiring and tracking specific generic type surface features was defined. A preliminary experiment definition and design of a video Landmark Acquisition and Tracking system is given. This device will search a 10-mile swath while orbiting the earth, looking for land/water interfaces such as coastlines and rivers

Priming third-party social exclusion does not elicit children's inclusion of out-group members

This study investigates how culture and priming 3- to 7-year-old children (N = 186) with third-party social exclusion affects their subsequent inclusion of out-group members. Children in societies that tend to value social independence (Germany, New Zealand) and interdependence (Northern Cyprus) were randomly assigned to minimal groups. Next, they watched video stimuli depicting third-party social exclusion (exclusion condition) or neutral content (control condition). We assessed children's recognition of the social exclusion expressed in the priming videos and their understanding of the emotional consequences thereof. We furthermore assessed children's inclusion behaviour in a ball-tossing game in which participants could include an out-group agent into an in-group interplay. Children across societies detected third-party social exclusion and ascribed lower mood to excluded than non-excluded protagonists. Children from Germany and New Zealand were more likely to include the out-group agent into the in-group interaction than children from Northern Cyprus. Children's social inclusion remained unaffected by their exposure to third-party social exclusion primes. These results suggest that children from diverse societies recognize social exclusion and correctly forecast its negative emotional consequences, but raise doubt on the notion that social exclusion exposure affects subsequent social inclusion

Associations Between Hearing Performance and Physiological Measures - An Overview and Outlook

The current paper summarises the research investigating associations between physiological data and hearing performance. An overview of state-of-the-art research and literature is given as well as promising directions for associations between physiological data and data regarding hearing loss and hearing performance. The physiological parameters included in this paper are: electrodermal activity, heart rate variability, blood pressure, blood oxygenation and respiratory rate. Furthermore, the environmental and behavioural measurements of physical activity and body mass index, alcohol consumption and smoking have been included. So far, only electrodermal activity and heart rate variability are physiological signals simultaneously associated with hearing loss or hearing performance. Initial findings suggest blood pressure and respiratory rate to be the most promising physiological measures that relate to hearing loss and hearing performance

Synthesis and Raman micro-spectroscopy investigation of Li7La3Zr2O12

The Li+ ion conductor Li7La3Zr2O12 was synthesized by solid state reaction as a ceramic with tetragonal and cubic crystal structure. The synthesis parameterswere varied for these polycrystalline samples, e.g. the starting materials for Li and Zr, the cruciblematerials and the thermal treatments. Product formation is sensitive to the ZrO2 starting powder aswell as the crucible material due to reactions between the powdermixture and the cruciblewall. In this study, only the use of an alumina crucible or the addition of alumina resulted in the successful preparation of cubic Li7La3Zr2O12. For single-crystal preparation, flux growth experiments were carried out at 1000 and 1200 \ub0C either in alumina crucibles lined with a gold foil or in magnesia crucibles and using Li2CO3 (Li2O) as flux. The small crystals were separated from the solidified flux by washing larger lumps in water. Irrespective of the additions of alumina, only tetragonal micro-crystals of Li7La3Zr2O12 were obtained. These micro-crystals were studied by micro-Raman scattering spectroscopy. Polarized Raman spectra were recorded either in nearly backscattering or 90\ub0 geometry. The majority of Raman modes expected for the tetragonal phase (space group I41/acd, Z=8) were satisfactorily displayed. So far, it has not been possible to make unambiguous symmetry assignments of the observed peaks because of the unknown orientation of the micro-crystals

Atomic effects in astrophysical nuclear reactions

Two models are presented for the description of the electron screening effects that appear in laboratory nuclear reactions at astrophysical energies. The two-electron screening energy of the first model agrees very well with the recent LUNA experimental result for the break-up reaction $He3(He3,2p)He^{4}$, which so far defies all available theoretical models. Moreover, multi-electron effects that enhance laboratory reactions of the CNO cycle and other advanced nuclear burning stages, are also studied by means of the Thomas-Fermi model, deriving analytical formulae that establish a lower and upper limit for the associated screening energy. The results of the second model, which show a very satisfactory compatibility with the adiabatic approximation ones, are expected to be particularly useful in future experiments for a more accurate determination of the CNO astrophysical factors.Comment: 14 RevTex pages + 2 ps (revised) figures. Phys.Rev.C (in production

Fluctuation Theorems for Entropy Production and Heat Dissipation in Periodically Driven Markov Chains

Asymptotic fluctuation theorems are statements of a Gallavotti-Cohen symmetry in the rate function of either the time-averaged entropy production or heat dissipation of a process. Such theorems have been proved for various general classes of continuous-time deterministic and stochastic processes, but always under the assumption that the forces driving the system are time independent, and often relying on the existence of a limiting ergodic distribution. In this paper we extend the asymptotic fluctuation theorem for the first time to inhomogeneous continuous-time processes without a stationary distribution, considering specifically a finite state Markov chain driven by periodic transition rates. We find that for both entropy production and heat dissipation, the usual Gallavotti-Cohen symmetry of the rate function is generalized to an analogous relation between the rate functions of the original process and its corresponding backward process, in which the trajectory and the driving protocol have been time-reversed. The effect is that spontaneous positive fluctuations in the long time average of each quantity in the forward process are exponentially more likely than spontaneous negative fluctuations in the backward process, and vice-versa, revealing that the distributions of fluctuations in universes in which time moves forward and backward are related. As an additional result, the asymptotic time-averaged entropy production is obtained as the integral of a periodic entropy production rate that generalizes the constant rate pertaining to homogeneous dynamics

Lattice instabilities of cubic NiTi from first principles

The phonon dispersion relation of NiTi in the simple cubic B2 structure is computed using first-principles density-functional perturbation theory with pseudopotentials and a plane-wave basis set. Lattice instabilities are observed to occur across nearly the entire Brillouin zone, excluding three interpenetrating tubes of stability along the (001) directions and small spheres of stability centered at R. The strongest instability is that of the doubly degenerate M5' mode. The atomic displacements of one of the eigenvectors of this mode generate a good approximation to the observed B19' ground-state structure.Comment: 11 pages, 3 figure

Impact of calcium on salivary α-amylase activity, starch paste apparent viscosity and thickness perception

Thickness perception of starch-thickened products during eating has been linked to starch viscosity and salivary amylase activity. Calcium is an essential cofactor for α-amylase and there is anecdotal evidence that adding extra calcium affects amylase activity in processes like mashing of beer. The aims of this paper were to (1) investigate the role of salivary calcium on α-amylase activity and (2) to measure the effect of calcium concentration on apparent viscosity and thickness perception when interacting with salivary α-amylase in starch-based samples. α-Amylase activity in saliva samples from 28 people was assessed using a typical starch pasting cycle (up to 95 °C). The activity of the enzyme (as measured by the change in starch apparent viscosity) was maintained by the presence of calcium, probably by protecting the enzyme from heat denaturation. Enhancement of α-amylase activity by calcium at 37 °C was also observed although to a smaller extent. Sensory analysis showed a general trend of decreased thickness perception in the presence of calcium, but the result was only significant for one pair of samples, suggesting a limited impact of calcium enhanced enzyme activity on perceived thickness