A novel, thermophilic filamentous anoxygenic phototrophic bacterium, strain isl-2T, was isolated from the Strokkur Geyser, Iceland. Strain isl-2T formed unbranched multicellular filaments with ...gliding motility. The cells formed no spores and stained Gram-negative. The existence of pili was described in a species of the genus Chloroflexus for the first time, to our knowledge. Optimal growth occurred at a pH range of 7.5-7.7 and at a temperature of 55 °C. Strain isl-2T grew photoheterotrophically under anaerobic conditions in the light and chemoheterotrophically under aerobic conditions in the dark. The major cellular fatty acids were C18 : 1ω9, C16 : 0, C18 : 0 and C18 : 0-OH. The major quinone was menaquinone-10. The photosynthetic pigments were bacteriochlorophylls c and a as well as β- and γ-carotenes. The results of phylogenetic analysis of the 16S rRNA gene sequences placed strain isl-2T into the genus Chloroflexus of the phylum Chloroflexi with Chloroflexus aggregans DSM 9485T as the closest relative (97.0 % identity). The whole-genome sequence of isl-2T was determined. Average nucleotide identity values obtained for isl-2T in comparison to available genomic sequences of other strains of members of the genus Chloroflexus were 81.4 % or less and digital DNA-DNA hybridisation values 22.8 % or less. The results of additional phylogenetic analysis of the PufLM and BchG amino acid sequences supported the separate position of the isl-2T phylotype from the phylotypes of other members of the genus Chloroflexus. On the basis of physiological and phylogenetic data as well as genomic data, it was suggested that isl-2T represents a novel species within the genus Chloroflexus, with the proposed name Chloroflexus islandicus sp. nov. The type strain of the species is isl-2T (=VKM B-2978T,=DSM 29225T,=JCM 30533T).
The paper focuses on the impact of an optically transparent protective coating of an AlSiN system on the short-time ultimate strength of quartz glass discs as delivered and after crater damage by ...impact particles simulating micrometeoroids. The statistical processing of the data discovers a negative correlation between the specimen ultimate strength and the crater damage. This allowed assessing the residual average and assured lifetime of coated space vehicle glass windows.
Dispersion of femtosecond laser pulses propagating in Ar, He, Kr, N(2), Ne, Xe, and their mixtures is measured by spectrally and spatially resolved interferometry. By varying the gas pressure in a ...4.5 m long tube between 0.05 mbar and ambient pressure, the first, second, and third order phase derivatives of broadband laser pulses are determined at 800 nm under standard conditions. The dispersion of gases and gas mixtures obeys the Lorentz-Lorenz formula with an accuracy of 0.7%. Based on the measured pressure dependent dispersion values in the near infrared and the refractive indices available from the literature for the ultraviolet and visible, a pressure dependent Sellmeier-type formula is fitted for each gas. These common form, two-term dispersion equations provide an accuracy between 4.1x10(-9) (Ne) and 4.3x10(-7) (Xe) for the refractive indices, from UV to near IR.
In this work, numerical heat transfer simulations of direct water-cooled gain modules for thin disk (TD) Ti:Sapphire (Ti:Sa) power amplifiers are presented. By using the TD technique in combination ...with the extraction during pumping (EDP) method 100-TW class amplifiers operating around 300 W average power could be reached in the future. Single and double-sided cooling arrangements were investigated for several coolant flow velocities. Simulations which upscale the gain module for multiple kilowatts of average power were also performed for large aperture Ti:Sa disks and for multiple disks with several coolant channels.
In this work, composites based on yttria-stabilized zirconia (3Y-TZP) with additives of 1.5 and 10 wt % multi-walled carbon nanotubes (MWCNTs) were studied. Samples were obtained by spark plasma ...sintering (SPS) at a temperature of 1500°C. It was found that, after high-temperature sintering, MWCNTs retain their structure and are located along the ZrO
2
grain boundaries forming a network structure. It was found that the addition of 1 wt % MWCNTs increases the relative composite density from 98.3 to 99.0%. It was noted that nanotubes can significantly affect the phase composition of composites. The addition of 5 wt % MWCNT partially limits the monoclinic–tetragonal phase transition of ZrO
2
, and the addition of 10 wt % MWCNTs leads to the formation of a cubic phase of zirconium carbide. It was found that fracture toughness of the composite with 10 wt % MWCNTs increases from 4.0 to 5.7 MPa m
1/2
.
The multi-component Al–Si–Re–O coating with a thickness of 3.5 μm was deposited on the quartz glass surface by the method of pulsed magnetron sputtering. Its structural phase state and optical and ...mechanical properties have been investigated. According to X-ray diffractometry and transmission electron microscopy, the structure of the coating is amorphous and has the following elemental composition: Al – 9.29 at.%, Si – 23 at.%, Re – 2.35 at.%, and O – 65.7 at.%. The present work studies the problem of crater formation under the bombardment of the quartz glass surface with Al–Si–Re–O coating by iron particles having a speed of 5–8 m/s. The study discovers protective properties of the Al–Si–Re–O coating manifested as an appreciable decrease of the surface density of the craters formed after impacts of iron microparticles as compared to the uncoated quartz glass. This effect is due to changes in the structure, phase composition, and mechanical properties of the glass surface layer coated by the reinforcing coating. The results show that the quartz glass with the Al–Si– Re–O coating remains transparent in the visible (
T
≥ 77%) and UV ranges (
T
≥ 23.8%).
Abstract
On the quartz glass specimens, visually transparent single-layer SiAlN and two-layer SiAlN/TaN films were applied to compare their protective properties against shock impact of high-velocity ...(5-8 km/s) iron microparticles. The tests performed using a two-stage light-gas gun have shown that the most effective coatings are two-layer films. The structure, optical and mechanical properties of the films were determined.
The propagation of high intensity laser beams is excessively affected by optical nonlinear effects, thereby the knowledge of the nonlinear refractive indices of the beam guiding media is ...indispensable in the design of laser systems and experiments. Apart from undesired self-focusing, several areas of modern laser spectroscopy can utilize optical nonlinearity, from LiDAR measurements to filamentation. In this paper we report on a direct measurement of pressure dependent nonlinear refractive index of Ar, N2, Ne, Xe, and air between 0.05 mbar and 1 bar, based on the powerful technique called spectrally and spatially resolved interferometry. In this way the total value of nonlinear refractive index is measured, that is the sum of all elementary phenomena contributing to the intensity dependent refractivity of the gases.
A new method to determine the peak intensity of focused relativistic laser pulses is experimentally justified. It is based on the measurement of spectra of electrons, accelerated in the beam waist. ...The detected electrons were emitted from the plasma, generated by nonlinear ionization of low-density gases (helium, argon, and krypton) in the focal area of a laser beam with the peak intensity >1020 W/cm2. The measurements revealed generation of particles with the maximum energy of a few MeV, observed at a small angle relative to the beam axis. The results are supported by numerical particle-in-cell simulations of a laser–low-density plasma interaction. The peak intensity in the focal region derived from experimental data reaches the value of 2.5 × 1020 W/cm2.
Wear and tear of concrete and reinforced concrete structures in harsh climatic conditions is analyzed as a fatigue process with various cumulative failures. For the criteria of their prediction, it ...is proposed to use dynamic models containing the kinetics of changes of informative and sensitive indicators of the constructive properties of concrete during cyclical freezing and thawing (CFT). An experimental-analytical generalization of the measurement of the following indicators is presented: strength, components of deformations, cracking, and the energy potential of concrete destruction during the exhaustion of its frost resistance. It is proposed, as a first approximation permissible under the conditions of the onset of fatigue parametric failures, to take the level of external temperature and humidity effects equivalent to (ultimately) 85 ÷ 90% of the frost resistance mark.
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