67 research outputs found
CONVECTIVE HEAT-EXCHANGE FEATURES IN SHORT CHANNELS WITH ULTIMATE ROUGHNESS
Augmentation heat transfer by convection created in channel made by impacted rings screw-shaped spiral of tubing. Results were obtained to calculate the coefficients of hydraulic friction in the Reynolds number range from 5000 to 50000
Extraction of Kaon Formfactors from K^- -> mu^- nu_mu gamma Decay at ISTRA+ Setup
The radiative decay K->mu nu gamma has been studied at ISTRA+ setup in a new
kinematical region. About 22K events of K^- -> mu^- nu_mu gamma have been
observed. The sign and value of Fv-Fa have been measured for the first time.
The result is Fv-Fa=0.21(4)(4).Comment: 11 pages, 21 figures, submitted to Phys. Lett.
Search for Heavy Neutrino in K->mu nu_h(nu_h-> nu gamma) Decay at ISTRA+ Setup
Heavy neutrino nu_h with m_h < 300MeV/c^2 can be effectively searched for in
kaon decays. We put upper limits on mixing matrix element |U_mu_h}|^2 for
radiatively decaying nu_h from K->mu nu_h (nu_h -> nu gamma) decay chain in the
following parameter region: 30MeV/c^2 < m_h < 80MeV/c^2; 10^{-11}sec < tau_h <
10^{-9}sec. For the whole region |U_{mu h}|^2 < 5 x 10^{-5} for Majorana type
of nu_h and | U_{\mu h}|^2 < 8 x 10^{-5} for the Dirac case.Comment: Published in Phys. Lett.
Predicting the Amplitude of a Solar Cycle Using the North-South Asymmetry in the Previous Cycle: II. An Improved Prediction for Solar Cycle~24
Recently, using Greenwich and Solar Optical Observing Network sunspot group
data during the period 1874-2006, (Javaraiah, MNRAS, 377, L34, 2007: Paper I),
has found that: (1) the sum of the areas of the sunspot groups in 0-10 deg
latitude interval of the Sun's northern hemisphere and in the time-interval of
-1.35 year to +2.15 year from the time of the preceding minimum of a solar
cycle n correlates well (corr. coeff. r=0.947) with the amplitude (maximum of
the smoothed monthly sunspot number) of the next cycle n+1. (2) The sum of the
areas of the spot groups in 0-10 deg latitude interval of the southern
hemisphere and in the time-interval of 1.0 year to 1.75 year just after the
time of the maximum of the cycle n correlates very well (r=0.966) with the
amplitude of cycle n+1. Using these relations, (1) and (2), the values 112 + or
- 13 and 74 + or -10, respectively, were predicted in Paper I for the amplitude
of the upcoming cycle 24. Here we found that in case of (1), the north-south
asymmetry in the area sum of a cycle n also has a relationship, say (3), with
the amplitude of cycle n+1, which is similar to (1) but more statistically
significant (r=0.968) like (2). By using (3) it is possible to predict the
amplitude of a cycle with a better accuracy by about 13 years in advance, and
we get 103 + or -10 for the amplitude of the upcoming cycle 24. However, we
found a similar but a more statistically significant (r=0.983) relationship,
say (4), by using the sum of the area sum used in (2) and the north-south
difference used in (3). By using (4) it is possible to predict the amplitude of
a cycle by about 9 years in advance with a high accuracy and we get 87 + or - 7
for the amplitude of cycle 24.Comment: 21 pages, 7 figures, Published in Solar Physics 252, 419-439 (2008
Crystal and molecular structures of 2-[1-(2-aminoethyl)-2-imidazolidinylidene]-2-nitro-acetonitrile (C7H11N5O2) and2,6-dianlino-5-hydroxy-3-nitro4H-pyrazolo[1,5-a]-pyrimidin-7-one monohydrate (C6H6N6O4 center dot H2O) from X-ray, synchroton and neutron powder diffraction data.
The crystal and molecular structures of 2-[1-(2-aminoethyl)-2-imidazolidinylidene]-2-nitroacetonitrile [C7H11N5O2; space group P21/n; Z = 4; a = 7.4889 (8), b = 17.273 (2), c = 7.4073 (8) Å, β = 111.937 (6)°], (I), and 2,6-diamino-5-hydroxy-3-nitro-4H-pyrazolo[1,5-a]pyrimidin-7-one monohydrate [C6H6N6O4·H2O; space group P21/n; Z = 4; a = 17.576 (3), b = 10.900 (2), c = 4.6738 (6) Å, β = 92.867 (8)°], (II), have been determined from X-ray, synchrotron and neutron powder diffraction data using various methods. The structures were originally solved from Guinier photographs with a grid search procedure and the program MRIA using a priori information from NMR and mass spectra on the possible geometry of the molecules. Because the conformation of molecule (I) changed during the bond-restrained Rietveld refinement, solvent water was found in (II) and, moreover, as both Guinier patterns were corrupted by texture, high-resolution texture-free synchrotron data were collected at the BM16 beamline, ESRF, to confirm the original results. Using the set of |F|
2
values derived from the synchrotron patterns after full-pattern decomposition procedures, the structures of (I) and (II) were solved by direct methods via
SHELXS96, SIRPOW.92 and POWSIM without any preliminary models of the molecules, and by Patterson search methods via
DIRDIF96 and PATSEE with the use of rigid fragments from each of the molecules. The neutron patterns allowed (I) and (II) to be solved using the grid search procedure and correct initial models of the molecules including H atoms. The results obtained from powder patterns measured on different devices demonstrate the high level of reproducibility and reliability of various powder software and equipment, with a certain preference for synchrotron facilities.</jats:p
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