Showing papers by "IPG Photonics published in 2013"

Multidisciplinary Evidences that Synechocystis PCC6803 Exopolysaccharides Operate in Cell Sedimentation and Protection against Salt and Metal Stresses

Abstract: Little is known about the production of exopolysaccharides (EPS) in cyanobacteria, and there are no genetic and physiological evidences that EPS are involved in cell protection against the frequently encountered environmental stresses caused by salt and metals. We studied four presumptive EPS production genes, sll0923, sll1581, slr1875 and sll5052, in the model cyanobacterium Synechocystis PCC6803, which produces copious amounts of EPS attached to cells (CPS) and released in the culture medium (RPS) as shown here. We show that sll0923, sll1581, slr1875 and sll5052 are all dispensable to the growth of all corresponding single and double deletion mutants in absence of stress. Furthermore, we report that sll0923, sll1581 and slr1875 unambiguously operate in the production of both CPS and RPS. Both sll1581 and slr1875 are more important than sll0923 for CPS production, whereas the contrary is true for RPS production. We show that the most EPS-depleted mutant, doubly deleted for sll1581 and slr1875, lacks the EPS mantle that surrounds WT cells and sorbs iron in their vicinity. Using this mutant, we demonstrate for the first time that cyanobacterial EPS directly operate in cell protection against NaCl, CoCl2, CdSO4 and Fe-starvation. We believe that our EPS-depleted mutants will be useful tools to investigate the role of EPS in cell-to-cell aggregation, biofilm formation, biomineralization and tolerance to environmental stresses. We also suggest using the fast sedimenting mutants as biotechnological cell factories to facilitate the otherwise expensive harvest of the producer cell biomass and/or its separation from products excreted in the growth media.

Industrial grade 100 kW power CW fiber laser

Abstract: 101.3 kW industrial fiber laser emitting at wavelength range 1070 nm would be presented. To the best of our knowledge, this is the most powerful continuous-wave laser system ever developed all over the world for industrial applications.

Raman spectroscopic properties and Raman identification of CaS-MgS-MnS-FeS-Cr2FeS4 sulfides in meteorites and reduced sulfur-rich systems

Abstract: –Raman spectra were acquired on a series of natural and synthetic sulfideminerals, commonly found in enstatite meteorites: oldhamite (CaS), niningerite or keilite((Mg,Fe)S), alabandite (MnS), troilite (FeS), and daubreelite (Cr 2 FeS 4 ). Natural samplescome from three enstatite chondrites, three aubrites, and one anomalous ungroupedenstatite meteorite. Synthetic samples range from pure endmembers (CaS, FeS, MgS) tocomplex solid solutions (Fe, Mg, Ca)S. The main Raman peaks are localized at 225, 285,360, and 470 cm 1 for the Mg-rich sulfides; at 185, 205, and 285 cm 1 for the Ca-richsulfides; at 250, 370, and 580 cm 1 for the Mn-rich sulfides; at 255, 290, and 365 cm 1 for the Cr-rich sulfides; and at 290 and 335 cm 1 for troilite with, occasionally, an extrapeak at 240 cm 1 . A peak at 160 cm 1 is present in all Raman spectra and cannot beused to discriminate between the different sulfide compositions. According to grouptheory, none of the cubic monosulfides oldhamite, niningerite, or alabandite shouldpresent first-order Raman spectra because of their ideal rocksalt structure. The occurrenceof broad Raman peaks is tentatively explained by local breaking of symmetry rules.Measurements compare well with the infrared frequencies calculated from first-principlescalculations. Raman spectra arise from activation of certain vibrational modes due toclustering in the solid solutions or to coupling with electronic transitions in semiconductorsulfides.INTRODUCTIONRecently, particular effort was put intounderstanding the occurrence of sulfur-rich phases inmagmatic systems and meteorites as well as in materialscience and metallurgy (e.g., Sinyakavo and Kosyakov2001; Holzheid and Grove 2002; Keil 2007; Liu et al.2007). The degassing of sulfur from volcanoes plays animportant role in the present and past atmosphereproperties, and in the geochemical cycle of sulfur in theEarth system (e.g., Farquhar et al. 2002; Moretti andOttonello 2005; Liu et al. 2007). Sulfur can take a largenumber of oxidation states, from 2 to 6+, and itoccurs in several gaseous and crystallized forms.Because of this large range of possible oxidation states,it remains a difficult element to study.The sulfide compounds are important phases inmeteorites (e.g., Keil 1989, 2007). Specifically, the majorpart of sulfur in meteorites is found either in troilite;FeS; or in other sulfides like oldhamite, CaS,

Edifice strength and magma transfer modulation at Piton de la Fournaise volcano

Abstract: [1] From 2003 to 2007, eruptive activity at Piton de la Fournaise was shown to follow cycles, comprising many summit/proximal eruptions and finishing by a distal eruption. GPS measurements evidenced striking asymmetric deformation between its western and eastern flanks. Horizontal displacements recorded during interdistal periods showed a characteristic amplitude at the top of the eastern flank. Displacements recorded at the base of the summit cone showed a bimodal distribution, with low amplitudes during interdistal periods and large ones during distal eruptions. To account for displacement asymmetry, characteristic amplitude, and large flank displacement, we modeled the volcanic edifice using a Drucker-Prager elastoplastic rheology. Friction angles of 15° and >30° were needed to model the displacements respectively during distal eruptions and interdistal periods; this change shows that strain weakening occurred during distal events. Large plastic displacement that occurred in the eastern flank during distal eruptions relaxed the horizontal elastic stress accumulated during interdistal periods; it triggered summit deflation, horizontal magma transfer, and distal flank eruption and reset the eruptive cycle. Our elastoplastic models also show that simple source geometries may induce large eastern flank displacements that would be explained by a complex geometry in a linear elastic edifice. Magma supply is often thought to control volcano's eruptive activity, with surface deformation reflecting changes in magma supply rate, the volcano's response being linear. Our results bring some evidences that on Piton de la Fournaise time-space discretization of magma transfer may be the result of the edifice's nonlinear response, rather than changes in magma supply.

Trachyte Phase Relations and Implication for Magma Storage Conditions in the Chaîne des Puys (French Massif Central)

Abstract: Petrological data have been acquired on the natural trachytes from the Chaine des Puys, French Massif Central, and on experimental products from phase equilibria in order to (i) constrain the storage conditions of the trachytic magmas that lead to explosive eruptions (dome destructions as block-and-ash flows or pumice-and-ash flows) and (ii) provide phase relationships and chemical compositions for differentiated alkaline liquids in intraplate continental context. Phase assemblages, proportions, and compositions have been determined on six trachytes with SiO2 contents varying from 62 to 69 wt % and alkali contents of 10.5-12.0 wt %. The samples contain up to 30 % of phenocrysts, mainly consisting of feldspar (15-17 %; plagioclase and/or alkali-feldspar), biotite (2-6 %; except in the SiO2-poorest sample), Fe-Ti oxides (1-3 %) ± amphibole (< 5 %), ± clinopyroxene (~1 %). All samples have apatite and zircon as minor phases and titanite has been found in one sample. Pristine glasses (melt inclusions or residual glasses) in pumice from explosive events are trachytic to rhyolitic (65-73 wt % SiO2 and 10.5-13.0 wt % alkali). H2O dissolved in melt inclusions and the biotite+alkali feldspar+magnetite hygrobarometer both suggest pre-eruptive H2O contents up to 8 wt %. These are so far the highest H2O contents ever reported for alkaline liquids in an intraplate continental context. Melt inclusions also contain ~3400 ppm chlorine, ~700 ppm fluorine, and ~300 ppm sulphur. Crystallisation experiments of the six trachytes have been performed between 200 and 400 MPa, 700 and 900°C, H2O saturation, and oxygen fugacity of NNO +1. The comparison between the natural and experimental phase assemblage, proportion, and composition suggests magma storage conditions at a pressure of 300-350 MPa (~10-12 km deep), melt H2O content ~8 wt % (close to saturation), an oxygen fugacity close to NNO~0.5, and temperatures increasing from 700 to 825°C with decreasing bulk SiO2 of the trachyte. The high H2O contents of the trachytes show that wet conditions may prevail during the differentiation of continental alkaline series. Regardless of the size of the magma reservoir assumed to have fed the trachyte eruptions, calculation of the thermal relaxation timescales indicates that the tapped reservoir(s) are likely to be still partially molten nowadays. The four northernmost edifices may correspond to a single large reservoir with a lateral extension of up to 10 km, which could be possibly reactivated in weeks to months if intercepted by new rising basalt batches.

The Impact of Fiber Laser Technology on the World Wide Material Processing Market

Abstract: The first fiber lasers appeared on the scene in the late 1990’s with the first kilowatt class fiber lasers appearing in early 2002. Since that time the output power of these devices have rapidly increased for both single mode and multimode devices. During 2012 the first 20 kilowatt single mode fiber laser was delivered followed by the first 100 kW multimode fiber laser in early 2013. Fiber Laser technology has gained worldwide acceptance in all major markets involved in material processing.

Thermal instabilities in a yield stress fluid: Existence and morphology

Abstract: We present new laboratory experiments on the development of thermal plumes out of a localized heat source in Carbopol, a yield-stress and shear-thinning fluid. Depending on the yield number Y 0 , which compares the thermally-induced stress to the yield stress, three different regimes obtain. For low Y 0 ( Y 0 (>260), thermal plumes develop. Their morphology differs from the mushroom-shape typically encountered in Newtonian fluids. Combined temperature and velocity field measurements show that a plug flow develops within the plume thermal anomaly, therefore producing a rising finger-shape. Moreover, light scattering highlights the development of a damaged zone prior to the plume onset, and the peculiar structure of the gel around the plume as it rises. This brings new insights into the solid–liquid transition of soft gels.

Implementation of sub-nanoseconds TDC in FPGA: applications to time-of-flight analysis in muon radiography

Abstract: Time-of-flight (tof) techniques are standard techniques in high energy physics to determine particles propagation directions. Since particles velocities are generally close to c, the speed of light, and detectors typical dimensions at the meter level, the state-of-the-art tof techniques should reach sub-nanosecond timing resolution. Among the various techniques already available, the recently developed ring oscillator TDC ones, implemented in low cost FPGA, feature a very interesting figure of merit since a very good timing performance may be achieved with limited processing ressources. This issue is relevant for applications where unmanned sensors should have the lowest possible power consumption. Actually this article describes in details the application of this kind of tof technique to muon tomography of geological bodies. Muon tomography aims at measuring density variations and absolute densities through the detection of atmospheric muons flux's attenuation, due to the presence of matter. When the measured fluxes become very low, an identified source of noise comes from backwards propagating particles hitting the detector in a direction pointing to the geological body. The separation between through-going and backward-going particles, on the basis of the tof information is therefore a key parameter for the tomography analysis and subsequent previsions.

Prominence in Triconstituent Compounds: Pitch Contours and Linguistic Theory

Abstract: According to the widely accepted Lexical Category Prominence Rule (LCPR), prominence assignment to triconstituent compounds depends on the branching direction. Left-branching compounds, that is, compounds with a left-hand complex constituent, are held to have highest prominence on the left-most constituent, whereas right-branching compounds have highest prominence on the second of the three constituents. The LCPR is, however, only poorly empirically supported. The present paper tests a new hypothesis concerning the prominence of triconstituent compounds and suggests a new methodology for the empirical investigation of compound prominence. According to this hypothesis, the prominence pattern of the embedded compound has a decisive influence on the prominence of the whole compound. Using a mixed-effects generalized additive model for the analysis of the pitch movements, it is shown that all triconstituent compounds have an accent on the first constituent irrespective of branching, and that the placement of a second, or even a third, accent is dependent on the prominence pattern of the embedded compound. The LCPR is wrong.

Numerical simulation of thermal plumes in a Herschel–Bulkley fluid

Abstract: We present a three dimensional numerical study of thermal plumes, developing from a localized heat source in a yield stress and shear thinning fluid. We assume that the fluid viscosity follows a Herschel–Bulkley law with a low shear rate viscosity plateau. Comparison of the plume onset time and morphology observed in the numerical study and in laboratory experiments with Carbopol shows good agreement. An extensive parameter study allows us to identify two local non-dimensional parameters that determine whether a plume rises through the fluid. The first parameter is the Bingham number, Bi, which compares the yield stress to the viscous stress. The second parameter, the yield number Ψ, compares the stress induced by the buoyancy of an equivalent hot sphere to the yield stress. We find that a plume develops only if Ψ > Ψc = 5 ± 1.2 and Bi 1. Hot fluid continues to rise from the bottom of the tank but spreads under an unyielded, high viscosity region at the top of the box.

Intermittency in spherical Couette dynamos

Abstract: We investigate dynamo action in three-dimensional numerical simulations of turbulent spherical Couette flows. Close to the onset of dynamo action, the magnetic field exhibits an intermittent behavior, characterized by a series of short bursts of the magnetic energy separated by low-energy phases. We show that this behavior corresponds to the so-called on-off intermittency. This behavior is here reported for dynamo action with realistic boundary conditions. We investigate the role of magnetic boundary conditions in this phenomenon.

Odd prime values of the Ramanujan tau function

Abstract: We study the odd prime values of the Ramanujan tau function, which form a thin set of large primes. To this end, we define LR(p,n):=τ(p n−1) and we show that the odd prime values are of the form LR(p,q) where p,q are odd primes. Then we exhibit arithmetical properties and congruences of the LR numbers using more general results on Lucas sequences. Finally, we propose estimations and discuss numerical results on pairs (p,q) for which LR(p,q) is prime.

Dynamics of iron-bearing borosilicate melts: Effects of melt structure and composition on viscosity, electrical conductivity and kinetics of redox reactions

Abstract: article i nfo Borosilicate melts; Atomic mobility; Dynamic properties; Melt structure; Redox reactions

Welding of high thicknesses using a fibre optic laser up to 30 kW

Abstract: The industrial applications of high-power fibre optic lasers include welding, 2D and 3D cutting, remote cutting and welding, brazing and surface treatments. The availability of fibre optic lasers with power outputs in excess of 10 kW might allow the development of novel fields of application in the welding of high thickness pieces: shipbuilding and offshore industries, pipe and cable manufacture and other heavy industry sectors. Carrying the beam by fibre optics allows high flexibility, even for the production of very large pieces, such as in the shipbuilding sector. This study describes the laser welding of high thickness pieces using a 30 kW laser and a 200 μm diameter fibre. On the one hand, such lasers allow a weld penetration depth of over 30 mm in a single pass, and very high process speeds for thinner materials on the other. Combining lasers with conventional arc welding techniques (hybrid welding) allows further optimization of weld quality and makes it possible to weld butt joints with a ‘gap’ of...

Prominence in triconstituent compounds: Pitch contours and linguistic theory

Abstract: According to the widely accepted Lexical Category Prominence Rule (LCPR), prominence assignment to triconstituent compounds depends on the branching direction. Left-branching compounds, that is, compounds with a left-hand complex constituent, are held to have highest prominence on the left-most constituent, whereas right-branching compounds have highest prominence on the second of the three constituents. The LCPR is, however, only poorly empirically supported. The present paper tests a new hypothesis concerning the prominence of triconstituent compounds and suggests a new methodology for the empirical investigation of compound prominence. According to this hypothesis, the prominence pattern of the embedded compound has a decisive influence on the prominence of the whole compound. Using a mixed-effects generalized additive model for the analysis of the pitch movements, it is shown that all triconstituent compounds have an accent on the first constituent irrespective of branching, and that the placement of a second, or even a third, accent is dependent on the prominence pattern of the embedded compound. The LCPR is wrong. Language and Speech

Lacustrine sediments and lichen transplants: two contrasting and complimentary environmental archives of natural and anthropogenic lead in the South Urals, Russia

Abstract: Lead (Pb) concentrations and isotope ratios of two different geochemical archives are compared; lake sediment cores and lichens (Hypogymnia physodes, naturally growing and transplanted) from a ca. 80 km-long transect centred on the Cu smelter and former mining town of Karabash, Ural Mountains, Russia. Lead concentrations in sediment cores from 10 lakes were generally low near their base and show an abrupt increase in their upper portions interpreted to coincide with the onset of large-scale smelting operations in 1910. Lead isotope ratios derived from 204Pb, 206Pb, 207Pb, 208Pb of the bottom layers differed significantly from those of the top. The top sediments have isotope ratios that show distinct end members, one of which was the stack dust from the Karabash smelter, which is similar to the Pb derived from ores from Sibay, a major mine in the Urals. The composition of the bottom sediment layers generally fall slightly off a mixing line between the top sediments and average Earth’s upper crust. Lichens transplanted from a reference site, as well as naturally growing lichens, sampled from southwest of the smelter have isotope ratios similar to those of the stack dust. Lichens to the northeast contained Pb from the smelter, but are increasingly influenced by other sources probably leaded petrol and local soils, and a signature derived from a source enriched in 207Pb. Vegetables collected from local kitchen gardens contained Pb from an additional atmospheric source, possibly coal. Our work confirms that: (1) Pb isotopes in lake sediments provide a long-term record of inputs and allows the characterisation of natural and anthropogenic sources; (2) Pb isotopes in lichens provide a short-term record of local and long-range atmospheric deposition at high spatial resolution and short time scales as they replace their Pb content within a few months; (3) determination of all four stable Pb isotopes is necessary for the identification of the sources of Pb and is extremely sensitive for discerning minor source signatures, even in an area with a dominant source such as a smelter. Particularly significant for the Karabash area is that ore-smelter-derived airborne Pb is a major component in the lake sediments and lichens but its contribution reaches insignificant levels ca. 40 km from the smelter.

Fe-doped II-VI mid-infrared laser materials for the 3 to 8 μm region

Abstract: We report on recent progress in development of new gain media for tunable (3–8 μm) mid-IR lasers as well as Fe:ZnS/Se lasers operating in CW (>1.5W), gain-switched (>1 mJ@7ns@lkHz) and long-pulse (>0.5 J@20μs) regimes.

Laser lift off systems and methods that overlap irradiation zones to provide multiple pulses of laser irradiation per location at an interface between layers to be separated

Abstract: Laser lift off systems and methods overlap irradiation zones to provide multiple pulses of laser irradiation per location at the interface between layers of material to be separated. To overlap irradiation zones, the laser lift off systems and methods provide stepwise relative movement between a pulsed laser beam and a workpiece. The laser irradiation may be provided by a non-homogeneous laser beam with a smooth spatial distribution of energy across the beam profile. The pulses of laser irradiation from the non-homogenous beam may irradiate the overlapping irradiation zones such that each of the locations at the interface is exposed to different portions of the non-homogeneous beam for each of the multiple pulses of the laser irradiation, thereby resulting in self-homogenization. Thus, the number of the multiple pulses of laser irradiation per location is generally sufficient to provide the self-homogenization and to separate the layers of material.

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.

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.

High power single mode ytterbium fiber laser system with single mode neodymium fiber source

Abstract: A high power fiber laser system emitting a substantially diffraction limited beam with a Gaussian intensity profile includes a single mode (“SM”) neodymium fiber pump source outputting a SM pump light; a seed laser operative to emit a SM signal light at a wavelength greater than that of the pump light; a SM DWM receiving and multiplexing the SM pump and signal lights. The disclosed system further includes a booster fiber amplifier which is configured with a frustoconically-shaped ytterbium (“Yb”) doped core receiving the pump and signal lights and configured with a small diameter input end which supports only a SM and a large diameter output end which is capable of supporting the SM and high order modes (:HOM”). The booster further has a cladding surrounding and coextending with the core, the core being configured for having intensity profiles of respective SMs of pump and signal lights overlap one another so that an overlap integral substantially equals to one (1) along an entire length of the core. The SM of the light signal extracts substantially the entire energy from the pump mode leaving the HOMs without amplification necessary to affect a quality of the diffraction limited beam of the system in a MW peak power range and hundreds of watt average power range.