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.

Physical characteristics and triggering mechanisms of the 2009-2010 landslide crisis at Montagne Pelée volcano, Martinique: : implication for erosional processes and debris-flow hazards

Abstract: Flank destabilizations are common processes in the life of a volcano. Apart from giant landslides with recurrence times of tens of thousands of years and whose deposits are identified in the bathymetry around the islands, less voluminous but more frequent erosional landslides contribute significantly to the morphological development of the topography. In this paper, we present a detailed description of a landslide sequence that occurred in 2009 and 2010 on the western flank of Montagne Pelee volcano, originating at the Samperre cliff. This sequence is characterized by two main events, in August 2009 and May 2010, and hundreds of smaller collapses. From seismic data and high resolution topographic data from airborne Lidar, collapses are counted and volumes of the main events are estimated. The May 2010 landslide has removed 2.1 millions of m3 of debris, which were subsequently remobilized during several hazardous lahars. The mean rates of erosion deduced from these volumes indicate that this kind of erosional landslide could represent a long term contribution of the same order of magnitude as giant flank collapses. The characterization of the runout of the landslides and of the Samperre cliff slopes provide important information for risk assessment, in particular for the risk of lahars that threaten the population living on the lower slopes.

10 W single-mode single frequency Tm-doped fiber amplifiers optimized for 1800-2020-nm band

Abstract: For the first time, a >10W single-mode Tm-doped amplifier is demonstrated. The all fiber format is optimized for single frequency signals in the 1800 - 2020 nm band. Natural Tm 3+ gain bandwidth is shifted towards the 1800nm and 2000nm region by selecting the fiber composition and length. No SBS-related issues were observed at levels of >10W of output power while using a single-frequency seed source. A simple model allowing the prediction of amplifier gain is presented.

Manganese accommodation in fossilised mastodon ivory and heat-induced colour transformation Evidence by EXAFS

Abstract: Odontolite or bone turquoise, a turquoise-blue coloured heated fossilised mastodon ivory or bone, is an imitation of the mineral turquoise used for the decoration of medieval art objects. Its colour origin can be ascribed to Mn 5+ traces in a tetrahedral environment of four oxygen atoms in an apatite matrix. The structural environment of Mn was investigated by means of extended X-ray absorption fine structure (EXAFS) in order to shed new light on the colour transformation of fossilised ivory induced by a thermal treatment. This was particularly difficult as the manganese concentration does not exceed trace amounts in fossilised ivory. EXAFS experiments confirm the presence of Mn 2+/3+/4+ ions before and Mn 5+ ions after thermal treatment in fossilised ivory and the location of Mn 5+ ions on a P analogous site in apatite.

Rotations in Lebanon inferred from new palaeomagnetic data and implications for the evolution of the Dead Sea Transform system

Abstract: Abstract A study carried out on widespread sites of the Aptian–Albian formations in Lebanon led to two palaeomagnetic directions corresponding to the primary magnetization (N=37 sites, D=307.1°, I=23.7°, k=18 and α95=5.5° after tilt correction and to a post-folding remagnetization (N=18 sites, D=346.3°, I=49.2°, k=108 and α95=3.2° before tilt correction). Comparison of these data with previous palaeomagnetic results for the Jurassic age in Lebanon and expected directions from African apparent polar wander path yields evidence of three different counter-clockwise regional rotations, of the order of 33° before Aptian deposition, of 11° during Late Miocene times, and of 18° since Miocene period. The two last rotations are related to the relative displacement of the African and Arabian plates. A model is proposed for the evolution of this particular Middle East area, in which the Dead Sea Transform shows a strong deviation relative to its main north–south orientation.

Robotic laser seam stepper

Abstract: A robotically operated laser seam stepper is configured with an elongated support column extending along a longitudinal axis and made from lightweight material. A support plate is displaceably mounted to the column while supporting thereon an optical head which is provided with optics. The optics is configured to direct a laser beam along a path towards a welding zone through a protective window of the optical head. The laser seam stepper further is structured with a first arm mounted to the support plate and extending along a longitudinal axis of the stepper diametrically opposite to the optical head. The inner surface of the displaceable arm defines a tunnel which is aligned with the optical head and axially traversed by the laser beam, a first axially flowing stream of pressurized gaseous medium, and by a second axially flowing stream of gaseous medium. The second stream, entering the tunnel at a pressure lower than that one of the first stream in response to a pressure gradient generated in the column, does not generate vortexes within the column. The first and second streams exit through the downstream end of the tunnel next to the welding zone. As the streams flow out, they carry out welding debris from the tunnel.