1,833 research outputs found

    Anomalous diffusion and Tsallis statistics in an optical lattice

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    We point out a connection between anomalous quantum transport in an optical lattice and Tsallis' generalized thermostatistics. Specifically, we show that the momentum equation for the semiclassical Wigner function that describes atomic motion in the optical potential, belongs to a class of transport equations recently studied by Borland [PLA 245, 67 (1998)]. The important property of these ordinary linear Fokker--Planck equations is that their stationary solutions are exactly given by Tsallis distributions. Dissipative optical lattices are therefore new systems in which Tsallis statistics can be experimentally studied.Comment: 4 pages, 1 figur

    Особенности вербализации концептов «инновация» и «innovation» в русском и английском языках (на материале научно-технических текстов)

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    Особенности вербализации концептов "инновация" и "innovation" в русском и английском языках . Цель работы - моделирование структур концептов инновация и innovation, а также их описание и сравнение. Объект исследования – группы признаков, образующие структуры концептов инновация и innovation.Concept "innovation" in Russian and English. The aim of the work is to model the structures of concepts of innovation and innovation, as well as their description and comparison. The object of the study is the groups of features that form the structure of concepts innovation and innovation

    Analysis of Oscillating Combustion for NOx-Reduction in Pulverized Fuel Boilers

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    Thermal power plants in different fields are regularly adapted to the state-of-the-art emissions standards, applying “The Best Available Techniques Reference”. Since 2016 in the power plant area new, more stringent limits for power plant units with a thermal output of more than 300 MW operated with black coal are valid. Usually, in order to reach the new limits e.g., for NOX emissions, downstream reduction processes (Selective Non-Catalytic Reduction, SNCR or Selective Catalytic eduction) are applied, which use of operating resources (essentially ammonia water) thereby increase. By the means of an xperimentally validated process, by which pulverized fuel is fed by oscillation through a swirl burner into a pilot ombustion chamber with a thermal output of 2.5 MW, nitrogen oxides can be reduced without further activities, for nstance from 450 mg/mN3 in non-oscillation operation mode (0 Hz) to 280 mg/mN3 in oscillation operation mode (3.5 Hz), normalized to an O2–content of 6% each. These findings were patented in EP3084300. Particularly promising are the experiments which utilize oscillation of a large portion of the burn out air instead of the fuel in order to minimize the fatigue of the pulverized fuel oscillator, amongst others. Thereby, the nitrogen conversion rate, which describes the ratio of NOX to fuel nitrogen, including thermal NOX can be reduced from 26% for non-oscillation operation mode down to 6%. The present findings show that fuel oscillation alone is not sufficient to achieve nitrogen oxides concentrations below the legislative values. Therefore, a combination of different primary (and secondary) measures is required. This paper presents the experimental results for oscillating coal-dust firing. Furthermore, an expert model based on a multivariate regression is developed to evaluate the experimental results

    FLORISTIC AND PHYTOGEOGRAPHIC ASPECTS OFARACEAE IN CERRO PIRRE (DARIEN, PANAMA)

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    The aroid flora in Panama includes 436 described species in 26 genera, representing the richest country of Araceae in Central America. Much of the existing knowledge of the Panamanian aroids has been generated in the last 50 years, mainly due to extensive taxonomic studies and, to a lesser extent, by floristic studies. Floristic studies generated valuable information to better understand biodiversity, especially in the poorly-explored areas. For this reason, the main objective of this work is to study the floristic composition of the aroids of a botanically important region: Cerro Pirre (Darién Province). As a result, 430 specimens were studied, comprising 94 species in 12 genera. The Aroid flora of Cerro Pirre is formed by species of wide geographic distribution (53%) and, to a lesser extent, endemic species (27%). Of the total species, approximately 43% are nomadic vines, 33% epiphytes, 23% terrestrial and a single species epilithic (1%). Ten new records for the flora of Cerro Pirre were recorded and one new record for Panama. Nine species new to science were discovered. The surprisingly high number of new records and new species emphasizes the need for complementary inventories, through field work in unexplored areas and herbarium work through the comprehensive review of botanical material

    Starve to Sustain - An Ancient Syrian Landrace of Sorghum as Tool for Phosphorous Bio-Economy?

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    Phosphorus (P) is an essential macronutrient, playing a role in developmental and metabolic processes in plants. To understand the local and systemic responses of sorghum to inorganic phosphorus (Pi) starvation and the potential of straw and ash for reutilisation in agriculture, we compared two grain (Razinieh) and sweet (Della) sorghum varieties with respect to their morpho-physiological and molecular responses. We found that Pi starvation increased the elongation of primary roots, the formation of lateral roots, and the accumulation of anthocyanin. In Razinieh, lateral roots were promoted to a higher extent, correlated with a higher expression of SbPht1 phosphate transporters. Infrared spectra of straw from mature plants raised to maturity showed two prominent bands at 1371 and 2337 cm−1, which could be assigned to P-H(H2) stretching vibration in phosphine acid and phosphinothious acid, and their derivates, whose abundance correlated with phosphate uptake of the source plant and genotype (with a higher intensity in Razinieh). The ash generated from these straws stimulated the shoot elongation and root development of the rice seedlings, especially for the material derived from Razinieh raised under Pi starvation. In conclusion, sorghum growing on marginal lands has potential as a bio-economy alternative for mineral phosphorus recycling

    Proton-Radical Interaction in Crude Oil - A Combined NMR and EPR Study

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    © 2018 American Chemical Society. We present a detailed study of electron/nuclear interaction in a specific crude oil by continuous-wave and pulsed EPR, electron-nuclear double resonance (ENDOR) at W-band (94 GHz), and fast field-cycling dynamic nuclear polarization (FFC-DNP) at X-band. A perceptible non-Overhauser (solid) effect is found at room temperature as a result of the polarization transfer from the intrinsic oil "free" radicals to the 1H nuclei with different dynamics. On the basis of the analysis of the longitudinal nuclear relaxation times, three dynamical components described by different electron-proton coupling parameters were found, which in combination with ENDOR provides information about the distribution of the radicals in the high-molecular oil components

    Supercooled confined water and the Mode Coupling crossover temperature

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    We present a Molecular Dynamics study of the single particle dynamics of supercooled water confined in a silica pore. Two dynamical regimes are found: close to the hydrophilic substrate molecules are below the Mode Coupling crossover temperature, TCT_C, already at ambient temperature. The water closer to the center of the pore (free water) approaches upon supercooling TCT_C as predicted by Mode Coupling Theories. For free water the crossover temperature and crossover exponent γ\gamma are extracted from power-law fits to both the diffusion coefficient and the relaxation time of the late α\alpha region.Comment: To be published, Phys. Rev. Lett., 4 pages, 3 figures, revTeX, minor changes in the figures, references added, changes in the tex

    Molecular velocity auto-correlation of simple liquids observed by NMR MGSE method

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    The velocity auto-correlation spectra of simple liquids obtained by the NMR method of modulated gradient spin echo show features in the low frequency range up to a few kHz, which can be explained reasonably well by a t3/2t^{-3/2} long time tail decay only for non-polar liquid toluene, while the spectra of polar liquids, such as ethanol, water and glycerol, are more congruent with the model of diffusion of particles temporarily trapped in potential wells created by their neighbors. As the method provides the spectrum averaged over ensemble of particle trajectories, the initial non-exponential decay of spin echoes is attributed to a spatial heterogeneity of molecular motion in a bulk of liquid, reflected in distribution of the echo decays for short trajectories. While at longer time intervals, and thus with longer trajectories, heterogeneity is averaged out, giving rise to a spectrum which is explained as a combination of molecular self-diffusion and eddy diffusion within the vortexes of hydrodynamic fluctuations.Comment: 8 pages, 6 figur
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