1,429 research outputs found
On a Possibility to Determine the Sign of the Polarized Gluon Distribution
We investigate the possibility to draw conclusions on the sign of the
spin-dependent gluon distribution, , from existing polarized
DIS data. The spin-dependent parton distributions , and are constructed
in the framework of a phenomenological procedure taking into account some
assumptions on signs of valence and sea parton distributions motivated by 't
Hooft's mechanism of quark-quark interaction induced by instantons. The axial
gluon anomaly and data on integral quark contributions to the proton spin,
, and , are also taken into
account. Predictions for the - and -dependencies of the polarized
proton and neutron structure functions, and , are compared to
experimental data. It is shown that the neutron structure function, , is
especially sensitive to the sign of . The results of our
analysis supports the conclusion that this sign should be positive.Comment: 14 pages, latex, 12 figure
A rationale for some directions of the development of resource territories: the complex ''meso-level'' problem
The article presents an approach to the analysis and evaluation of integrated investment projects, which consist of infrastructure facilities and industrial clusters allocated to poorly developed areas rich in natural resources. This study shows the feasibility of a public-private partnership during the construction of infrastructure facilities in order to minimize the risks and maximize the benefits. The conceptual framework of the resulting approach is associated with the ideas and principles of «impact investing» («creation of shared values») and inclusive economic development. These are increasingly used worldwide, especially to accelerate the socio-economic development of backward countries and territories. The article presents an international experience and explains the relevance of best practices in Russia. The authors identified methodological problems associated with the application of traditional methods to the evaluation of economic effects of project investing under the conditions of high uncertainty. The authors explain why it is necessary to use models and methods (real options analysis and fuzzy cognitive models) that allow researchers to directly take into account the uncertainty and project risks. The novelty of the article is the methodological tools for evaluating the socio-economic efficiency of complex projects combining the development of infrastructure and minerals. The proposed approach was used to provide a rationale for a road construction project in the Berezovsky district of the Khanty-Mansi Autonomous Okrug. The authors showed opportunities to generate a set of institutional, organizational, and financial conditions under which the implementation of the project will be attractive to both investors and government and will bring socio-economic benefits to this territory. The proposed approach and tools can be used for a socio-economic strategic decision-making process to justify infrastructure projects in resource-rich regions.The theoretical and methodological results presented in the article were obtained during the research funded by the Russian Science Foundation (Project No. 14–18–02345)
Z-Scaling and Inclusive Particle Production in p-p Collisions at High-pT
The properties of particle production in pp collisions are basis for analysis
of pA and AA interactions and verification of theory. We analyzed inclusive
particle production using z-scaling established in proton-proton and
proton-antiproton collisions at the U70, ISR, Tevatron and RHIC. This scaling
reflects symmetry of hadron structure, interaction and particle formation. It
is shown that new data on charged hadron and pi0-meson spectra obtained in pp
collisions at the Relativistic Heavy Ion Collider confirm the z-scaling.Comment: 7 pages, LaTeX, 4 figures, presented at the XVII International
Conference on Ultra Relativistic Nucleus-Nucleus Collisions "Quark
Matter'2004", January 11-17, 2004, Oakland, US
Anodic dissolution of gallium in alkali metal chloride melts
Gallium and gallium based alloys can be potentially used in pyrochemical and pyroelectrochemical reprocessing of spent nuclear fuels, particularly for separating actinides and rare earth fission products. However, the electrochemical behavior of gallium in high temperature molten salt electrolytes is very little studied. The present work was aimed at investigating the processes taking place during anodic dissolution of gallium in fused alkali chlorides (the ternary 6NaCl–9KCl–5CsCl eutectic mixture) and determining the ratio of gallium chloro-species in different oxidation states formed and remained in the melt. The experiments were performed between 550 and 750 °C, and the anodic current density varied from 0.024 to 0.094 A/cm2. Anodic polarization and coulometry were used, and the results obtained demonstrated that two gallium species, Ga(I) and Ga(III), were formed as a result of gallium anodic dissolution. The ratio between these two oxidation states depended on temperature and anodic current density. The method of processing the experimental data and the calculated values of the ratio of gallium ionic forms in the system under various conditions are presented
Jet Energy Density in Hadron-Hadron Collisions at High Energies
The average particle multiplicity density dN/deta is the dynamical quantity
which reflects some regularities of particle production in low-pT range. The
quantity is an important ingredient of z-scaling. Experimental results on
charged particle density are available for pp, pA and AA collisions while
experimental properties of the jet density are still an open question. The goal
of this work is to find the variable which will reflect the main features of
the jet production in low transverse energy range and play the role of the
scale factor for the scaling function psi(z) and variable z in data
z-presentation. The appropriate candidate is the variable we called "scaled jet
energy density". Scaled jet energy density is the probability to have a jet
with defined ET in defined xT and pseudorapidity regions. The PYTHIA6.2 Monte
Carlo generator is used for calculation of scaled jet energy density in
proton-proton collisions over a high energy range (sqrt s = 200-14000 GeV) and
at eta = 0. The properties of the new variable are discussed and sensitivity to
"physical scenarios" applied in the standard Monte Carlo generator is noted.
The results of scaled jet energy density at LHC energies are presented and
compared with predictions based on z-scaling.Comment: 11 pages, LaTeX, 8 figures, Presented at the XVII International
Baldin Seminar on High Energy Physics Problems "Relativistic Nuclear Physics
& Quantum Chromodynamics", Dubna, Russia, September 27 - October 2, 200
Influence of Silicon on Temperature Dependence of Thermal Conductivity of Al–Si–Fe Alloys
Temperature dependence analysis of thermal conductivity was carried out for series of aluminum alloys with 1% Fe (mass%) and different content of silicon starting from 0% to 6% (mass%). It is shown that the best alloy for heat exchange applications is alloy with 4% of silicon (mass%). Temperature dependence of thermal conductivity shows the strong decreasing character for silicon-alloyed samples in comparison to pure aluminum.
Keywords: aluminum–silicon alloys, thermal conductivity, heat exchange, iron, cast alloys, structure, temperatur
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