Apparatus for making curved reflectors Patent

Forming mold for polishing and machining curved solar magnesium reflector with reinforcing rib

Process sequence produces strong, lightweight reflectors of excellent quality

Large compound curved surfaces for collecting and concentrating radiation are fabricated by the use of several common machining and forming processes. Lightweight sectors are assembled into large reflectors. With this concept of fabrication, integrally stiffened reflective sectors up to 25 square feet in area have been produced

Method and apparatus for making curved reflectors Patent

Fabrication of curved reflector segments for solar mirro

Interfaces between highly incompatible polymers of different stiffness: Monte Carlo simulations and self-consistent field calculations

We investigate interfacial properties between two highly incompatible polymers of different stiffness. The extensive Monte Carlo simulations of the binary polymer melt yield detailed interfacial profiles and the interfacial tension via an analysis of capillary fluctuations. We extract an effective Flory-Huggins parameter from the simulations, which is used in self-consistent field calculations. These take due account of the chain architecture via a partial enumeration of the single chain partition function, using chain conformations obtained by Monte Carlo simulations of the pure phases. The agreement between the simulations and self-consistent field calculations is almost quantitative, however we find deviations from the predictions of the Gaussian chain model for high incompatibilities or large stiffness. The interfacial width at very high incompatibilities is smaller than the prediction of the Gaussian chain model, and decreases upon increasing the statistical segment length of the semi-flexible component.Comment: to appear in J.Chem.Phy

The Relation between Solar Eruption Topologies and Observed Flare Features I: Flare Ribbons

In this paper we present a topological magnetic field investigation of seven two-ribbon flares in sigmoidal active regions observed with Hinode, STEREO, and SDO. We first derive the 3D coronal magnetic field structure of all regions using marginally unstable 3D coronal magnetic field models created with the flux rope insertion method. The unstable models have been shown to be a good model of the flaring magnetic field configurations. Regions are selected based on their pre-flare configurations along with the appearance and observational coverage of flare ribbons, and the model is constrained using pre-flare features observed in extreme ultraviolet and X-ray passbands. We perform a topology analysis of the models by computing the squashing factor, Q, in order to determine the locations of prominent quasi-separatrix layers (QSLs). QSLs from these maps are compared to flare ribbons at their full extents. We show that in all cases the straight segments of the two J-shaped ribbons are matched very well by the flux-rope-related QSLs, and the matches to the hooked segments are less consistent but still good for most cases. In addition, we show that these QSLs overlay ridges in the electric current density maps. This study is the largest sample of regions with QSLs derived from 3D coronal magnetic field models, and it shows that the magnetofrictional modeling technique that we employ gives a very good representation of flaring regions, with the power to predict flare ribbon locations in the event of a flare following the time of the model

Neutron-irradiation effects in LaO0.9F0.1FeAs superconductor

The effect of atomic disorder induced by neutrons irradiation on superconducting and normal state properties of polycrystalline LaFeAsO_0.9F_0.1 was investigated. The irradiation of the sample by a moderate neutron fluence F = 1.6*1019 cm^-2 at Tirr = 50 +- 10 C leads to the suppression of superconductivity which recovers almost completely after annealing at temperatures Tann < 750 C. It is shown that the reduction of superconducting transition temperature Tc under atomic disordering is not determined solely by the value of Hall concentration nH, i.e. doping level, but is governed by the reduction of electronic relaxation time. This behavior can be described qualitatively by universal Abrikosov-Gorkov equation which presents evidence on the anomalous type of electrons pairing in Fe-based superconductors.Comment: 8 pages, 11 figure