224 research outputs found

    Thermalization of gluons at RHIC: Dependence on initial conditions

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    We investigate how thermalization of gluons depends on the initial conditions assumed in ultrarelativistic heavy ion collisions at RHIC. The study is based on simulations employing the pQCD inspired parton cascade solving the Boltzmann equation for gluons. We consider independently produced minijets with pT>p0=1.32.0p_T > p_0=1.3 \sim 2.0 GeV and a color glass condensate as possible initial conditions for the freed gluons. It turns out that full kinetic equilibrium is achieved slightly sooner in denser system and its timescale tends to saturate. Compared with the kinetic equilibration we find a stronger dependence of chemical equilibration on the initial conditions.Comment: 8 pages, 4 figures; Contribution to Proceedings of the Quark-Gluon Plasma Thermalization workshop, Vienna, Austria, August 10-12, 200

    Graphene nanoribbons with zigzag and armchair edges prepared by scanning tunneling microscope lithography on gold substrates

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    The properties of graphene nanoribbons are dependent on both the nanoribbon width and the crystallographic orientation of the edges. Scanning tunneling microscope lithography is a method which is able to create graphene nanoribbons with well defined edge orientation, having a width of a few nanometers. However, it has only been demonstrated on the top layer of graphite. In order to allow practical applications of this powerful lithography technique, it needs to be implemented on single layer graphene. We demonstrate the preparation of graphene nanoribbons with well defined crystallographic orientation on top of gold substrates. Our transfer and lithography approach brings one step closer the preparation of well defined graphene nanoribbons on arbitrary substrates for nanoelectronic applications

    Different sensing mechanisms in single wire and mat carbon nanotubes chemical sensors

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    Chemical sensing properties of single wire and mat form sensor structures fabricated from the same carbon nanotube (CNT) materials have been compared. Sensing properties of CNT sensors were evaluated upon electrical response in the presence of five vapours as acetone, acetic acid, ethanol, toluene, and water. Diverse behaviour of single wire CNT sensors was found, while the mat structures showed similar response for all the applied vapours. This indicates that the sensing mechanism of random CNT networks cannot be interpreted as a simple summation of the constituting individual CNT effects, but is associated to another robust phenomenon, localized presumably at CNT-CNT junctions, must be supposed.Comment: 12 pages, 5 figures,Applied Physics A: Materials Science and Processing 201

    Generalized thermodynamic uncertainty relations

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    We analyze ensemble in which energy (E), temperature (T) and multiplicity (N) can all fluctuate and with the help of nonextensive statistics we propose a relation connecting all fluctuating variables. It generalizes Lindhard's thermodynamic uncertainty relations known in literature.Comment: 13 pages, 2 figures, version to occur in Physica A (2011); doi:10.1016/j.physa.2011.05.00

    Opposite tendency between yield and taste of organic tomato by increasing biochar doses in a slightly humous arenosol

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    Received: February 4th, 2022 ; Accepted: April 6th, 2022 ; Published: April 28th, 2022 ; Correspondence: [email protected] tomato is the edible berry of the plant Solanum lycopersicum. Tomato plants are widely grown in temperate climates worldwide and are mostly cultivated as annuals. The objective of this study was to understand the interrelation between fruit quality of tomato, some soil biological parameters, and the addition of increasing biochar (BC) soil amendment doses. BC is an industrial product, made from organic waste by pyrolysis. Its use in the soil is known to improve fertility and several soil functions. Among organic, ecological conditions, a field experiment was performed in a type of slightly humous arenosol soil. Effect of increasing doses of biochar (BC) (0.5-, 1.0-, 2.5-, 5.0, 10 m/m% and control) was studied. Nutrient content and Total Soluble Solid (TSS) of the fruits, the ripeness, and the marketable/non-marketable ratio of yield were assessed. The presence of some cultivable microbial physiological groups (fungi, bacteria) and the soil-dehydrogenase activity (DHA) was estimated. Results represented that the changes of fruit TSS content was not linear with the increasing doses of BC. The increased yield (+53%) had an inverse correlation with the TSS content of the berry's pulps, and the content was lowest at the highest BC dose. Optimum doses of BC were considered, like 1–2.5 m/m%, supported by the nutritive element content (+55% N, +76% P, +83% K) and enhanced microbial activities (+45% DHA). Grouping the parameters by Pearson Correlation Coefficient, the biochar amendment was a driving factor for tomato growth, with certain dose limits in the studied organic agricultural practice

    Canonical Ensemble of Initial States Leading to Chiral Fluctuations

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    In energetic heavy ion collisions, if quark-gluon plasma is formed, its hadronization may lead to observable critical fluctuations, i.e., DCC formation. The strength and observability of these fluctuations depend on the initial state. Here we study the canonical ensemble of initial states of chiral fluctuations in heavy ion collisions and the probability to obtain observable domains of chiral condensates.Comment: 13 pages (figures included) Accepted for publication in Phys. Rev.
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