Normal Vibrations in Near-Conservative Self-Excited and Viscoelastic Nonlinear Systems

International audienceA perturbation methodology and power series are utilized to the analysis of nonlinear normal vibration modes in broad classes of finite-dimensional self-excited nonlinear systems close to conservative systems taking into account similar nonlinear normal modes. The analytical construction is presented for some concrete systems. Namely, two linearly connected Van der Pol oscillators with nonlinear elastic characteristics and a simplest two-degrees-of-freedom nonlinear model of plate vibrations in a gas flow are considered. Periodical quasinormal solutions of integro-differential equations corresponding to viscoelastic mechanical systems are constructed using a convergent iteration process. One assumes that conservative systems appropriate for the dominant elastic interactions admit similar nonlinear normal modes

Pentaquarks in the Jaffe-Wilczek approximation

The masses of $uudd\bar s$, $uudd\bar d$ and $uuss\bar d$ pentaquarks are evaluated in a framework of both the Effective Hamiltonian approach to QCD and spinless Salpeter using the Jaffe--Wilczek diquark approximation and the string interaction for the diquark--diquark--antiquark system. The pentaquark masses are found to be in the region above 2 GeV. That indicates that the Goldstone boson exchange effects may play an important role in the light pentaquarks. The same calculations yield the mass of $[ud]^2\bar c$ pentaquark $\sim$ 3250 MeV and $[ud]^2\bar b$ pentaquark $\sim$ 6509 MeV.Comment: 14 pages, 2 tables, LaTeX2e. References correcte

Vibrating the QCD string

The large distance behaviour of the adiabatic hybrid potentials is studied in the framework of the QCD string model. The calculated spectra are shown to be the result of interplay between potential-type longitudinal and string-type transverse vibrations.Comment: LaTeX2e, 9 pages, 2 Postscript figures, final version to appear in Yad.Fi

Kazakhstan-Siberian spring common wheat identification according to glutenin and gliadin composition

Within ten years, the Kazakhstan-Siberian nursery net for spring common wheat improvement (KASIB) working under the auspices of CIMMYT (Intenational Maize and Wheat Improvement Center) characterized accessions of five cultivar blocks with regard to the compositions of gliadin (1B/1R translocation), glutenin HMW and LMW subunits, and grain hardness. HMW glutenin compositions for 188 homogeneous variety samples are given in accordance with UPOV (Union for the Protection of New Varieties of Plants) regulations and 27, 28 and 29 features in tests for uniformity, distinctness, and stability. Most spring wheat cultivars possess the glutenin spectra 2* 7+9 5+10” (40 %), “2* 7+9 2+12” (up to 30 %), and “17+95+10” (8 %). The Kazakhstan varietal gene pool includes genotypes with a new subunit 4 + 10 on 1D in samples of Erythrospermum 55/94-01-20 and Phyton 41. Cultivar Iridost is noted as carrying the relatively rare allele 5,5 + 10 on chromosome 1D. This allele was previously identified in Tselinogradka, Tselinnaya 24, and Akmola 3 cultivars. The rare subunit 7*+ 8 is typically present in E-607 and E-757. The last three KASIB blocks (8-9; 10-11; 12-13) show higher levels of uniformity: up to 74–84 %. The 1BL.1RS wheat-rye translocation is more frequently identified in accessions by Siberian Scientific Research Institute of Agriculture and Eastern Kazakhstan Research Institute of Agriculture breeding in each KASIB block and also in all the accessions presented by the companies Kurgansemena and Agrosemkonsal and selected by the Fiton company. Varieties Altaiskaya 105, Kurganskaya 5, Lutescens 1300, Phyton 42, Lutescens 53/95-98-1, Lutescens 53/88-94-12, Lutescens 54; Lutescens 30-94, Erythrospermum 607, and Aktobe 1574 showed the whole range of variability in grain hardness (from middle soft to hard) under different growth conditions

Theoretical Research on the Pipe Rolling Process in Order to Determine the Deformation of the Pipe Billet and the Load on the Rolling Tool

The technology of the shell case rolling into the rough pipe on an automatic mill of the pipe-rolling plant PRP 220 was considered. In case of the pipe rear end stability losing for a special thin-walled assortment of rolling products the theoretical research was carried out based on the FEM. As the result of the research the nature of such flaw as a "fin" on the end of the pipe was investigated, the evaluation of the loading on the automatic mill for the PRP 220 was obtained for different process parameters. © Published under licence by IOP Publishing Ltd

Glueballs, gluerings and gluestars in the d=2+1 SU(N) gauge theory

The 3d gluodynamics which governs the large T quark gluon plasma is studied in the framework of the field correlator method. Field correlators and spacial string tension are derived through the gluelump Green's functions. The glueball spectrum is calculated both in C=-1 as well as in C=+1 sectors, and multigluon bound states in the form of "gluon rings" and "gluon stars" are computed explicitly. Good overall agreement with available lattice data is observed.Comment: 19 page

Di-Pion Decays of Heavy Quarkonium in the Field Correlator Method

Mechanism of di-pion transitions $nS\to n'S\pi\pi(n=3,2; n'=2,1)$ in bottomonium and charmonium is studied with the use of the chiral string-breaking Lagrangian allowing for the emission of any number of $\pi(K,\eta),$ and not containing fitting parameters. The transition amplitude contains two terms, $M=a-b$, where first term (a) refers to subsequent one-pion emission: $\Upsilon(nS)\to\pi B\bar B^*\to\pi\Upsilon(n'S)\pi$ and second term (b) refers to two-pion emission: $\Upsilon(nS)\to\pi\pi B\bar B\to\pi\pi\Upsilon(n'S)$. The one-parameter formula for the di-pion mass distribution is derived, $\frac{dw}{dq}\sim$(phase space) $|\eta-x|^2$, where $x=\frac{q^2-4m^2_\pi}{q^2_{max}-4m^2_\pi},$ $q^2\equiv M^2_{\pi\pi}$. The parameter $\eta$ dependent on the process is calculated, using SHO wave functions and imposing PCAC restrictions (Adler zero) on amplitudes a,b. The resulting di-pion mass distributions are in agreement with experimental data.Comment: 62 pages,8 tables,7 figure

Magnetostimulated Chandges of Microhardness in Potassium Acid Phthalate Crystals

A decrease in microhardness along the (010) cleavage in potassium acid phthalate single crystals by 15--18% after the application of a permanent magnetic field was revealed for the first time. It is shown that the effect revealed is of the volume character. The role of interlayer water in the processes stimulated by a magnetic field is studied., Interlayer water plays does not cause the observed changes it only plays the part of an indicator of these changes in potassium acid phthalate crystals in a magnetic field. It is established that microhardness in the (100) plane of the crystal in an applied a magnetic field first increases by 12--15% and then remains constant in time within the accuracy of the experiment. The possibility of varying the crystal structure of potassium acid phthalate crystals by applying magnetic fields inducing rearrangement in the system of hydrogen bonds or in the defect structure is discussed.Comment: 6 pages, 7 figure

Baryon magnetic moments in the QCD string approach

Magnetic moments of baryons composed of light and strange quarks are computed for the first time through the only parameter of the model -- string tension $\sigma$. Resulting theoretical values differ from the experimental ones typically by about 10%.Comment: LaTeX, 13 pages; misprints are correcte

Glueball spectrum and the Pomeron in the Wilson loop approach

Using a nonperturbative method based on asymptotic behaviour of Wilson loops we calculate masses of glueballs and corresponding Regge-trajectories. The only input is string tension fixed by meson Regge slope, while perturbative contributions to spin splittings are defined by standard alpha_s values. The masses of lowest glueball states are in a perfect agreement with lattice results. The leading glueball trajectory which is associated with Pomeron is discussed in details and its mixing with f and f' trajectories is taken into account.Comment: LaTeX2e, 49 pages, 2 figure