Properties of discrete breathers in graphane from ab initio simulations

A density functional theory (DFT) study of the discrete breathers (DBs) in graphane (fully hydrogenated graphene) was performed. To the best of our knowledge, this is the first demonstration of the existence of DBs in a crystalline body from the first-principle simulations. It is found that the DB is a robust, highly localized vibrational mode with one hydrogen atom oscillating with a large amplitude along the direction normal to the graphane plane with all neighboring atoms having much smaller vibration amplitudes. DB frequency decreases with increase in its amplitude, and it can take any value within the phonon gap and can even enter the low-frequency phonon band. The concept of DB is then used to propose an explanation to the recent experimental results on the nontrivial kinetics of graphane dehydrogenation at elevated temperatures.Comment: 20.07.14 Submitted to PhysRev

Measurement of light mesons at RHIC by the PHENIX experiment

The PHENIX experiment at RHIC has measured a variety of light neutral mesons ($\pi^{0}$, K$_{S}^{0}$, $\eta$, $\omega$, $\eta^{\prime}$, $\phi$) via multi-particle decay channels over a wide range of transverse momentum. A review of the recent results on the production rates of light mesons in p+p and their nuclear modification factors in d+Au, Cu+Cu and Au+Au collisions at different energies is presented.Comment: 5 pages, 4 figures, talk given at Hard Probes 2008 conference in La Toja, Spain. submitted to EPJ

Recent Demographic Change in the Rio Grande Valley of Texas: The Importance of Domestic Migration

The present study examines the role of domestic migration in a massive demographic change in the Rio Grande Valley (RGV) of Texas with a special focus on ethnic composition of migration flows. Specifically, using two datasets derived from the Current Population Survey (CPS) and American Community Survey (ACS), this project: (1) outlines demographic profiles of domestic inbound and outbound migrants; (2) identifies determinants of migration for different types of movers; and (3) predicts the change in the Index of Dissimilarity (IT) at the census-tract level in the RGV. Results indicate that: (1) compared to stayers, Anglos were overrepresented among all migrant categories in the RGV; (2) leavers were likely to be motivated by career/employment opportunities outside the Valley, while affordable housing in the Valley was the primary motivating factor for newcomers; (3) recently arrived Hispanic immigrants became more segregated. The most important finding is that, compared to Hispanics, Anglos were not ‘pushed’ from the Valley by a growing Mexican-American population but became more segregated

Radio emission from satellite-Jupiter interactions (especially Ganymede)

Analyzing a database of 26 years of observations of Jupiter from the Nan\c{c}ay Decameter Array, we study the occurrence of Io-independent emissions as a function of the orbital phase of the other Galilean satellites and Amalthea. We identify unambiguously the emissions induced by Ganymede and characterize their intervals of occurrence in CML and Ganymede phase and longitude. We also find hints of emissions induced by Europa and, surprisingly, by Amalthea. The signature of Callisto-induced emissions is more tenuous.Comment: 14 pages, 7 figures, in "Planetary Radio Emissions VIII", G. Fischer, G. Mann, M. Panchenko and P. Zarka eds., Austrian Acad. Sci. Press, Vienna, in press, 201

Plate Heat-exchangers in Modern Waste Heat Recovery Systems of Hot Blast Stoves and Other Metallurgical Equipment

One of the main factors which defines modern economy is energy efficiency, namely, rationality of use of natural resources, first of all fuel resources, their economic use. Energy saving and energy efficiency improvement should be considered as one of the main sources of future economic growth. Keywords: heat recovery system, economic and ecological effect, plate heatexchangers, ribbed panel, laser welding, ribbed panels, heating uni

ϕ\phi- meson Production at RHIC energies using the PHENIX Detector

Light vector mesons are among the most informative probes to understand the strongly coupled Quark Gluon Plasma created at RHIC. The suppression of light mesons at high transverse momentum, compared to expectations from scaled $p+p$ results, reflects the properties of the strongly interacting matter formed. The $\phi$-meson is one of the probes whose systematic measurement in $p+p$, $d+Au$ and $Au+Au$ collisions can provide useful information about initial and final state effects on particle production. The mass, width and branching ratio of the $\phi$-meson decay in the di-kaon and di-electron decay channels could be modified in \au collisions due to the restoration of chiral symmetry in the QGP. The PHENIX experiment at RHIC has measured $\phi$-meson production in various systems ranging form $p+p$, $d+Au$ to $Au+Au$ collisions via both its di-electron and di-kaon decay modes. A summary of PHENIX results on invariant spectra, nuclear modification factor and elliptic flow of the $\phi$-meson are presented here