IPG Photonics

About: IPG Photonics is a based out in . It is known for research contribution in the topics: Laser & Fiber laser. The organization has 903 authors who have published 1241 publications receiving 63339 citations.

Stereological Analysis of Fracture Networks along Cylindrical Galleries

Abstract: The intersections between three-dimensional fracture networks consisting of constant- and variable-size disks with a gallery were systematically analyzed. Exact and approximate analytical formulae were derived for the numbers of partial or full intersections. These predictions were verified by Monte Carlo simulations. Trace length distributions were studied by numerical techniques for various disk distributions. These simulations showed that differences between various disk distributions are very small when trace length distributions with the same average and standard deviations are compared.

Numerical Modeling of Two-Phase Gravitational Granular Flows with Bottom Topography

Abstract: We study a depth-averaged model of gravity-driven mixtures of solid grains and fluid moving over variable basal surface. The particular application we are interested in is the numerical description of geophysical flows such as avalanches and debris flows, which typically contain both solid material and interstitial fluid. The depth-averaged mass and momentum equations for the solid and fluid components form a non-conservative system, where non-conservative terms involving the derivatives of the unknowns couple together the sets of equations of the two phases. The system can be shown to be hyperbolic at least when the difference of velocities of the two constituents is sufficiently small. We numerically solve the model equations in one dimension by a finite volume scheme based on a Roe-type Riemann solver. Well-balancing of topography source terms is obtained via a technique that includes these contributions into the wave structure of the Riemann solution.

Role of Structural Fe(III) and Iron Oxide Nanophases in Mullite Coloration

Abstract: Six mullite samples, derived from heat-treated natural kaolinites with various iron content, were investigated and compared to synthetic monophasic mullite. They were analyzed by X-ray diffraction, diffuse reflectance spectroscopy, and electron paramagnetic resonance. To quantify mullite coloration, the CIE colorimetric system was used. In contrast to synthetic mullite, samples showed charge transfer bands involving O2− and Fe3+ ions as well as ferric crystal-field transitions due to Fe3+ ions in iron oxide nanoparticles. Absorption edges showed red shifts. The resulting yellowness, saturation of which increased with the content of iron oxide nanoparticles, is direct evidence for the coloring effect of Fe3+ ions.

Explosive style, magma degassing and evolution in the Chaimilla eruption, Villarrica volcano, Southern Andes

Abstract: Villarrica (Chile) is a basaltic stratovolcano, cur- rently in an open-conduit condition. It now has relatively fre- quent Strombolian and effusive eruptions, but it had large explosive eruptions in prehistoric times. Among them, the most recent eruption was Chaimilla, which occurred about 3100 years ago and produced deposits that indicate complex, multiphase eruptive dynamics. Significant differences in min- eralogy and glass compositions of the erupted scoria suggest the eruption was fed by two distinct magma batches with similar bulk compositions but distinct crystallization and degassing histories. The lower sequence scoria has a complex crystal assemblage with several crystal populations produced by mixing between a relatively degassed magma containing Fo75-79 olivine, normally or reversely zoned plagioclase (An70-94) and augite (type 1 magma), and a subordinate vol- ume of more-primitive and more volatile-rich magma rising from depth (type 2 magma) and carrying normally zoned pla- gioclaseandhigher-Mg(Fo81-85)olivinecrystals.Type2mag- ma was the main component emitted during the larger and more explosive eruptive phase that deposited the upper sequence. The Chaimilla eruption occurred under closed- vent conditions and was fed by water-rich magmas. When comparedwiththe petrologicalfeaturesofthe magma current- ly erupted at Villarrica, which has slightly more-evolved bulk compositions, lower crystal content and lower water content, these results suggest that the evolution in eruptive style of the volcano from highly explosive to a lava lake/Strombolian ac- tivity corresponds to significant changes in the shallow plumbing system (which is now at much shallower depths); these plumbing-system changes were not associated with sig- nificant changes in the parental magma compositions.