Ball Lightning as Source of High-Energy Particles When It Enters a Dense Medium

Experiments have been carried out to study the anomalous passage of laboratory-produced ball lightning through solid-state sheets. The passing of the ball lightning within the standard model can be explained by cascading generation of particles at entering of high-energetic protons of the ball lightning into a dense matter. The process of energy conversion of its own poloidal magnetic field of the ball lightning into the kinetic energy of its charged particles occurs in this case. The energy of protons becomes sufficient for the generation of charged pions and their subsequent cascade decay. The decay of pions leads to the appearance of negative and positive muons, as well as muon antineutrino and muon neutrino. This fact is confirmed by the presence of a passed ball lightning and a high potential of variable polarity in the region above the solid-state sheet after the ball lightning passing through it. The dark ball lightning also found was in the experiments. The laboratory ball lightning opens up new perspectives in many areas of research and applications and may have a positive impact on attempts to solve the energy problem based on muon-catalyzed nuclear fusion.

Effect of Milling Time on Co<SUB>0.5</SUB>Zn<SUB>0.5</SUB>Fe<SUB>2</SUB>O<SUB>4</SUB>Microstructure and Particles Size Evolution via the Mechanical Alloying Method

Nanocrystalline CoZn-ferrite was fabricated by a high-energy milling method by mixing Fe3O4+CoO+ZnO. The structural properties of the milled powder at different milling times were analysed so to ascertain the diffusion of CoO and ZnO into the tetrahedral and octahedral sites using mechanical alloying method. The effect of mechanical alloying towards particle size was also investigated. The XRD spectra indicated the precursors reacted during milling with the diffusion of ZnO and followed by CoO into their respective crystallographic sites. SEM micrographs showed the agglomeration of powders due to high energy milling and TEM images confirmed that the particles of the materials were of nanosize dimension. In addition, the results show that the grain possesses a single-phase CoZn-ferrite structure in a typical size of ~16–30 nm. The experiment reveals that nanosize CoZn-ferrite can be obtained after the powder is milled for about 8 hours at room temperature. The mechanism and efficiency of the synthesis of the technique are also discussed in this paper.

BASKETBALL SCORING IN NBA GAMES:AN EXAMPLE OF COMPLEXITY

Scoring in a basketball game is a highly dynamic, non-linear process. NBA teams try to be more and more competitive each season. For instance, they incorporate into their rosters the best players in the world. This and other mechanisms concur to make the scoring process in NBA games exciting and rarely predictable. This paper is to study the behavior of timing and scoring in basketball gaines. The authors analyze all the games in five NBA regular seasons （2005-06, 2006-07, 2007-08, 2008-09, 2009-10）, for a total of 6150 games. Scoring does not behave uniformly; therefore, the authors also analyze the distributions of the differences in points in the basketball games. To further analyze the behavior of the tail of the distribution, the authors also carry out a semilog-plot and a log-log plot to verify whether this trend approaches a Poisson distribution or a PL. This paper reveals different areas of behavior related to the score, with specific instances of time that could be considered tipping points of the game. The presence of these critical points suggests that there are phase transitions where the dynamic scoring of the games varies significantly.

Down-and up-conversion processes in Nd^(3+)/Yb^(3+)co-doped sodium calcium silicate glasses with concomitant Yb^(2+)assessment

Novel Nd^(3+)/Yb^(3+)co-doped sodium calcium silicate glasses were prepared by melting quenching method:Spectroscopic study was carried out as a function of doping content by fixing sensitizer(Nd^(3+))concentration to 0.2 mol%and adjusting activator(Yb^(3+))from 0 to 1.0 mol%.The energy transfer(ET)mechanisms between Nd^(3+)and Yb^(3+)are discussed based on their energy levels and excitation powerdependence emission intensity.Results show that the presence of Yb^(2+)might be considered for the Nd^(3+)-free and co-doped samples.The ET was confirmed by the down-conversion NIR emission spectra of the doped and co-doped samples under excitation at 808 nm.The mechanisms observed seem to involve only one VIS absorbed photon for each NIR emitted via direct energy transfer between^(4)F_(3/2)of Nd^(2+)and^(2)F_(5/2)of Yb^(3+)compensated by phonon assistance due to energy gap between these levels.The efficiency of ET increases with the ytterbium content up to almost 90%for the sample with 1 mol%of Yb2O3,which was evaluated by lifetime measurements.Up-conversion photoluminescence by exciting trivalent ions of neodymium(808 nm)and ytterbium(975 nm)is reported.The observed up-converted emission bands are related to the 4f-4f transitions of Nd^(3+)and the spin-forbidden 5d-4f transition of Yb^(2+).Nd^(3+)upconversion emission is observed under 975 nm excitation,presenting an almost quadratic emission dependence with power excitation,which suggests that two laser photons participate in the up-conversion(UC)process,showing that ET occurs by a phonon-assisted energy transfer and cooperative energy transfer.