437 research outputs found

    PYROXENITE VEINS WITHIN SSZ PERIDOTITES – EVIDENCE OF MELT-ROCK INTERACTION (EGIINGOL MASSIF), MAJOR AND TRACE ELEMENT COMPOSITION OF MINERALS

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    Evidence of melt-rock reaction between suprasubduction zone (SSZ) peridotites and island arc boninititc and tholeiitic melts are identified. This process is the cause of replacive dunites and pyroxenite veins forming, which are represent the ways of island-arc melts migration. The peridotite-melt interaction is confirmed by compositional features of rocks and minerals. Influence of boninitic melt in peridotites of South Sandwich island arc leads to increasing of TiO2 and Cr-number (Cr#) in spinels [Pearce et al., 2000] e.g. REE patterns of clinopyroxene from Voykar are equilibrium to boninitic melts [Belousov et al., 2009]. We show that pyroxenites are formed sequential, orthopyroxenites are originated firstly, websterites – after, and the main forming process is interaction of SSZ peridotites with percolating boninite-like melts.Evidence of melt-rock reaction between suprasubduction zone (SSZ) peridotites and island arc boninititc and tholeiitic melts are identified. This process is the cause of replacive dunites and pyroxenite veins forming, which are represent the ways of island-arc melts migration. The peridotite-melt interaction is confirmed by compositional features of rocks and minerals. Influence of boninitic melt in peridotites of South Sandwich island arc leads to increasing of TiO2 and Cr-number (Cr#) in spinels [Pearce et al., 2000] e.g. REE patterns of clinopyroxene from Voykar are equilibrium to boninitic melts [Belousov et al., 2009]. We show that pyroxenites are formed sequential, orthopyroxenites are originated firstly, websterites – after, and the main forming process is interaction of SSZ peridotites with percolating boninite-like melts

    Quantum key distribution using a triggered quantum dot source emitting near 1.3 microns

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    We report the distribution of a cryptographic key, secure from photon number splitting attacks, over 35 km of optical fiber using single photons from an InAs quantum dot emitting ~1.3 microns in a pillar microcavity. Using below GaAs-bandgap optical excitation, we demonstrate suppression of multiphoton emission to 10% of the Poissonian level without detector dark count subtraction. The source is incorporated into a phase encoded interferometric scheme implementing the BB84 protocol for key distribution over standard telecommunication optical fiber. We show a transmission distance advantage over that possible with (length-optimized) uniform intensity weak coherent pulses at 1310 nm in the same system.Comment: 4 pages, 4 figure

    Longitudinal peculiarities of meridional circulation in lower thermosphere and mesosphere

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    Average monthly longitudinal profiles of geostrophic wind in winter are presented. Positive values correspond to meridional movements from north to south. It is concluded that the normal longitudinal meridional circulation is characterized by the presence of sectors where meridional flows do not change their direction in the course of time comparable with synoptic periods. The longitudinal distribution of meridional wind in middle latitudes taken from the analysis results of radiometeor and ionospheric stations observational data obtained in 1976 to 1980 are presented. Meridional winds have a longitudinal variability that is equivalent to both the warm and cold half years

    Use of Non-distractive Testing AU-E Technology to Evaluate Hearth Conditions at CherMK–SEVERSTAL

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    Intensive operation of blast furnace allows increase in production of hot metal and profitability of Iron & Steel Works. However, blast furnace life could be sacrificed if no measures are taken to protect refractory lining and to build stable accretion. CherMK and Hatch developed a systematic approach to monitor conditions of BF hearth lining using Acousto Ultrasonic-Echo (AU-E) non-destructive testing developed by Hatch. Multiple testing of blast furnaces revealed problematic areas with accelerated refractory deterioration and minimal thickness, formation of elephant foot, extent of accretion and speed of refractory wear, cracks and other anomalies. Improvement in coke quality, periodical staves washing, the addition of titania, grouting, etc., were recommended and implemented to prolong furnace life while maintaining the intensity of furnace operation. Keywords: blast furnace inspection and monitoring, non-destructive testing (NDT), refractory deterioration, blast furnace campaig

    PETROGRAPHY AND MINERALOGY OF RETROGRADE METAPERIDOTITES FROM ALAG KHADNY ACCRETIONARY WEDGE (SW MONGOLIA): FLUID MODIFICATION IN SUPRASUBDUCTION ZONE

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    The Main Mongolian Lineament (MML) separates northern “Caledonian” tectonic province from southern “Hercynian” in SW part of Mongolia of the Central Asian Orogenic Belt (CAOB). The position of Eastern part of MML is widely discussed at recent time, since, this is an important for reconstruction of geodynamic evolution of this region. Some researchers suggest that ophiolite from the Erdene Uul and Maykhan Tsakhir Uul mountain ranges are Eastern part of an ophiolitic nappe system thrust northwards over the Dzabkhan-Baydrag continent, namely the Khantaishir and the Dariv ophiolites [Štípská et al., 2010; Buriánek et al., 2017]. Others have a different view, they suggest that investigated ophiolites refers to Gobi-Altai ophiolite system (523±5 – 518±6 Ma), which likely formed in front of the Gobi Altai microcontinent by initiation of a new southdipping subduction zone following arc–microcontinent collision in Northwest Mongolia [Jian et al., 2014]. However, ophiolites of this critical region of Mongolian the CAOB have not been investigated in detail.The Main Mongolian Lineament (MML) separates northern “Caledonian” tectonic province from southern “Hercynian” in SW part of Mongolia of the Central Asian Orogenic Belt (CAOB). The position of Eastern part of MML is widely discussed at recent time, since, this is an important for reconstruction of geodynamic evolution of this region. Some researchers suggest that ophiolite from the Erdene Uul and Maykhan Tsakhir Uul mountain ranges are Eastern part of an ophiolitic nappe system thrust northwards over the Dzabkhan-Baydrag continent, namely the Khantaishir and the Dariv ophiolites [Štípská et al., 2010; Buriánek et al., 2017]. Others have a different view, they suggest that investigated ophiolites refers to Gobi-Altai ophiolite system (523±5 – 518±6 Ma), which likely formed in front of the Gobi Altai microcontinent by initiation of a new southdipping subduction zone following arc–microcontinent collision in Northwest Mongolia [Jian et al., 2014]. However, ophiolites of this critical region of Mongolian the CAOB have not been investigated in detail

    MECHANISMS OF DESTRUCTION AND SYNTHESIS OF LIQUID MEDIA, USED IN THE FOOD INDUSTRY UNDER NON-EQUILIBRIUM CONDITIONS

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    The formation of food liquid medium structures containing at least 70 % of disperse particles with high dispersiveness has been considered. The possible formation mechanisms of food liquid medium structure when slow (hydrodynamic) and quick (acoustic) processes create favorable conditions for cavitation have been studied. The possibility to control these processes for initiation of mechanical and kinetic reactions that change the structure of the medium has been demonstrated. The invert syrup has been selected as the study object. The change in the invert syrup structure before and after such cavitation treatment has been recorded with the use of metallographic microscope Nikon Eclipse MA100. The decrease in disperse phase sizes from 2–3 µm to 0.1–0.4 µm along with establishing the high uniformity of component distribution as compared to the syrup without cavitation process treatment has been detected. The formation of food liquid medium structures containing at least 70 % of disperse particles with high dispersiveness has been considered. The possible formation mechanisms of food liquid medium structure when slow (hydrodynamic) and quick (acoustic) processes create favorable conditions for cavitation have been studied. The possibility to control these processes for initiation of mechanical and kinetic reactions that change the structure of the medium has been demonstrated. The invert syrup has been selected as the study object. The change in the invert syrup structure before and after such cavitation treatment has been recorded with the use of metallographic microscope Nikon Eclipse MA100. The decrease in disperse phase sizes from 2–3 µm to 0.1–0.4 µm along with establishing the high uniformity of component distribution as compared to the syrup without cavitation process treatment has been detected.
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