203 research outputs found

    Recycling and Networking

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    In recent years, the notion that for environmental and legislative reasons improvements The national environmental policies and practice, including recycling strategies, are desirable and in many cases might be economically beneficial has been gaining ground. Although according to recent surveys the state of the environment in Hungary is in line with average values of the European Union, the main challenge for the country is to achieve sustainability in economic, environmental and technological terms. With a view to accession to the European Union, a harmonisation strategy must be worked out and implemented. This harmonisation strategy includes not only legislative aspects, but also social, technological, financial and logistic considerations.Because of the high logistic costs of achieving closed loop recycling systems, the author focuses on logistic aspects and tasks of the improvement phases and concentrates on the possibilities of networking and co-operation. The paper describes some possible alternative solutions for co-operative recycling processes, to improve the following logistic parameters: delivery times, accuracy of supply, running times, utilization of capacities, stock quantities, flexibility, transparency of the system, high forwarding capability, quality of product. The logistic aspects of co-operation will be analysed from the viewpoint of a closed loop economy

    Kinetics of four-wave mixing for a 2D magneto-plasma in strong magnetic fields

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    We investigate the femtosecond kinetics of an optically excited 2D magneto-plasma at intermediate and high densities under a strong magnetic field perpendicular to the quantum well (QW). We assume an additional weak lateral confinement which lifts the degeneracy of the Landau levels partially. We calculate the femtosecond dephasing and relaxation kinetics of the laser pulse excited magneto-plasma due to bare Coulomb potential scattering, because screening is under these conditions of minor importance. In particular the time-resolved and time-integrated four-wave mixing (FWM) signals are calculated by taking into account three Landau subbands in both the valance and the conduction band assuming an electron-hole symmetry. The FWM signals exhibit quantum beats mainly with twice the cyclotron frequency. Contrary to general expectations, we find no pronounced slowing down of the dephasing with increasing magnetic field. On the contrary, one obtains a decreasing dephasing time because of the increase of the Coulomb matrix elements and the number of states in a given Landau subband. In the situation when the loss of scattering channels exceeds these increasing effects, one gets a slight increase at the dephasing time. However, details of the strongly modulated scattering kinetics depend sensitively on the detuning, the plasma density, and the spectral pulse width relative to the cyclotron frequency.Comment: 13 pages, in RevTex format, 10 figures, Phys. Rev B in pres

    Coherent Control for a Two-level System Coupled to Phonons

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    The interband polarizations induced by two phase-locked pulses in a semiconductor show strong interference effects depending on the time tau_1 separating the pulses. The four-wave mixing signal diffracted from a third pulse delayed by tau is coherently controlled by tuning tau_1. The four-wave mixing response is evaluated exactly for a two-level system coupled to a single LO phonon. In the weak coupling regime it shows oscillations with the phonon frequency which turn into sharp peaks at multiples of the phonon period for a larger coupling strength. Destructive interferences between the two phase-locked pulses produce a splitting of the phonon peaks into a doublet. For fixed tau but varying tau_1 the signal shows rapid oscillations at the interband-transition frequency, whose amplitude exhibits bursts at multiples of the phonon period.Comment: 4 pages, 4 figures, RevTex, content change

    Biolubricant production in ionic liquids by enzymatic esterification

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    Esterification of oleic acid with short carbon chain alcohols gives biofuels, with long chain alcohols biolubricants can be produced. Previously biolubricants was successfully produced from fusel oil and isoamyl-alcohol substrates by enzyme catalised esterification, but solution of polar substrates was problematic, that was solved by using ionic liquids. The optimal reaction parameters such as substrate molar ratios, initial water content, amount of enzyme and type of ionic liquid were determined by experimental design using Statistica software. Some of the ionic liquids have catalytic effect by itself, therefore control reactions were necessary to determine which ionic liquid has negligible catalytic effect. In five of the six investigated ionic liquid the yield was the same without enzyme, while in case of B[mim]PF6, the yield was negligible. In shorter time higher yield was achieved in presence of ionic liquid against other methods. Increasing the temperature results higher yield till a limit, higher temperature does not make more product, but thermal desactivation of the enzyme was not occur

    Variability of M giant stars based on Kepler photometry: general characteristics

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    M giants are among the longest-period pulsating stars which is why their studies were traditionally restricted to analyses of low-precision visual observations, and more recently, accurate ground-based data. Here we present an overview of M giant variability on a wide range of time-scales (hours to years), based on analysis of thirteen quarters of Kepler long-cadence observations (one point per every 29.4 minutes), with a total time-span of over 1000 days. About two-thirds of the sample stars have been selected from the ASAS-North survey of the Kepler field, with the rest supplemented from a randomly chosen M giant control sample. We first describe the correction of the light curves from different quarters, which was found to be essential. We use Fourier analysis to calculate multiple frequencies for all stars in the sample. Over 50 stars show a relatively strong signal with a period equal to the Kepler-year and a characteristic phase dependence across the whole field-of-view. We interpret this as a so far unidentified systematic effect in the Kepler data. We discuss the presence of regular patterns in the distribution of multiple periodicities and amplitudes. In the period-amplitude plane we find that it is possible to distinguish between solar-like oscillations and larger amplitude pulsations which are characteristic for Mira/SR stars. This may indicate the region of the transition between two types of oscillations as we move upward along the giant branch.Comment: 12 pages, 13 figures, accepted for publication in MNRAS. The normalized light curves are available upon reques

    Associations between plant density and yield components using different sowing times in wheat (Triticum aestivum L.)

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    The yield potential of wheat depends not only on genetic × environmental interactions, but also on various agronomic factors such as sowing date or the seed rate used for sowing. The main aim of this work was to determine possible correlations between the effects of different sowing dates and plant densities on the yield components of a collection of 48 wheat genotypes. Two-way analysis of variance on the data revealed that both sowing date and plant density, as main components, only had a minor effect on the yield component patterns. Correlation analysis, however, indicated that the sowing date had a greater effect on the yield components, while plant density was in closer correlation with the heading time (r = 0.90). The patterns determined for individual yield components at two different sowing dates and plant densities showed significant differences for spike length, spike fertility, grain number in the main spike, number of productive tillers, grain number on side tillers, mean grain number and grain weight. Genotypes that carry the winter (recessive) alleles of genes regulating vernalisation processes (VRN-A1, VRN-B1, VRN-D1) and the sensitive (recessive) alleles of the two genes responsible for photoperiod sensitivity (PPD-B1, PPD-D1) may have better tillering and consequently higher grain yield, though this may depend greatly on the year

    First isolation and characterization of Brucella microti from wild boar

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    Background: Brucella microti was first isolated from common vole ( Microtus arvalis ) in the Czech Republic in Central Europe in 2007. As B. microti is the only Brucella species known to live in soil, its distribution, ecology, zoonotic potential, and genomic organization is of particular interest. The present paper is the first to report the isolation of B. microti from a wild boar ( Sus scrofa ), which is also the first isolation of this bacterial species in Hungary. Results: The B. microti isolate was cultured, after enrichment in Brucella -selective broth, from the submandibular lymph node of a female wild boar that was taken by hunters in Hungary near the Austrian border in September 2014. Histological and immunohistological examinations of the lymph node sections with B. abortus- , B. suis- and B. canis -specific sera gave negative results. The isolate did not require CO 2 for growth, was oxidase, catalase, and urease positive, H 2 S negative, grew well in the presence of 20 μ g/ml basic fuchsin and thionin, and had brownish pigmentation after three days of incubation. It gave strong positive agglutination with anti-A and anti-M but had a negative reaction with anti-R monospecific sera. The API 20 NE test identified it as Ochrobactrum anthropi with 99.9 % identity, and it showed B. microti -specific banding pattern in the Bruce- and Suis-ladder multiplex PCR systems. Whole genome re-sequencing id entified 30 SNPs in orthologous loci when compared to the B. microti reference genome available in GenBank, and the ML VA analysis yielded a unique profile. Conclusions: Given that the female wild boar did not develop any clinical disease, we hypothesize that this host species only harboured the bacterium, serving as a possible reservoir capable of maintaining and spreading this pathogen. The infectious source could have been either a rodent, a carcass that had been eaten or infection occurred via the boar rooting in soil. The low number of discovered SNPs suggests an unexpectedly high level of genetic homogeneity in this Brucella species. Keywords: Biochemistry, Brucella microti , Immunohistochemistry, MLVA, Morphology, Wild boar, Whole genome sequencing, Hungary

    Microscopic modeling of photoluminescence of strongly disordered semiconductors

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    A microscopic theory for the luminescence of ordered semiconductors is modified to describe photoluminescence of strongly disordered semiconductors. The approach includes both diagonal disorder and the many-body Coulomb interaction. As a case study, the light emission of a correlated plasma is investigated numerically for a one-dimensional two-band tight-binding model. The band structure of the underlying ordered system is assumed to correspond to either a direct or an indirect semiconductor. In particular, luminescence and absorption spectra are computed for various levels of disorder and sample temperature to determine thermodynamic relations, the Stokes shift, and the radiative lifetime distribution.Comment: 35 pages, 14 figure
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