Importance of Granular Structure in the Initial Conditions for the Elliptic Flow

We show effects of granular structure of the initial conditions (IC) of hydrodynamic description of high-energy nucleus-nucleus collisions on some observables, especially on the elliptic-flow parameter v2. Such a structure enhances production of isotropically distributed high-pT particles, making v2 smaller there. Also, it reduces v2 in the forward and backward regions where the global matter density is smaller, so where such effects become more efficacious.Comment: 4 pages, 5 figure

Fluctuation of the Initial Conditions and Its Consequences on Some Observables

We show effects of the event-by-event fluctuation of the initial conditions (IC) in hydrodynamic description of high-energy nuclear collisions on some observables. Such IC produce not only fluctuations in observables but, due to their bumpy structure, several non-trivial effects appear. They enhance production of isotropically distributed high-pT particles, making v2 smaller there. Also, they reduce v2 in the forward and backward regions where the global matter density is smaller, so where such effects become more efficacious. They may also produce the so-called ridge effect in the two large-pT particle correlation.Comment: 6 pages, 6 figures, presented at the IV Workshop on Particle Correlations and Femtoscopy (WPCF2008), Krakow, Poland, 11-14 Sep 200

Third post-Newtonian dynamics of compact binaries: Equations of motion in the center-of-mass frame

The equations of motion of compact binary systems and their associated Lagrangian formulation have been derived in previous works at the third post-Newtonian (3PN) approximation of general relativity in harmonic coordinates. In the present work we investigate the binary's relative dynamics in the center-of-mass frame (center of mass located at the origin of the coordinates). We obtain the 3PN-accurate expressions of the center-of-mass positions and equations of the relative binary motion. We show that the equations derive from a Lagrangian (neglecting the radiation reaction), from which we deduce the conserved center-of-mass energy and angular momentum at the 3PN order. The harmonic-coordinates center-of-mass Lagrangian is equivalent, {\it via} a contact transformation of the particles' variables, to the center-of-mass Hamiltonian in ADM coordinates that is known from the post-Newtonian ADM-Hamiltonian formalism. As an application we investigate the dynamical stability of circular binary orbits at the 3PN order.Comment: 31 pages, to appear in Classical and Quantum Gravit

SPRINKMOD - Simulation of pressure and discharge distributions in pressurized irrigation systems: graphical interface and strategy of design.

SPRINKMOD is a computer model that simulates pressure and flow rate distributions along pipes and laterals of pressurized irrigation systems. The software runs in a WINDOWS environment and simulates irrigation systems having multiple pump stations combined in series and/or in parallel, booster pump stations, parallel pipes and looping pipes in addition to more traditional, branched pressurized irrigation systems. Lateral types include hand-move, wheel line and center pivot lateral that may utilize pressure regulators and booster pumps. Leakage is included in the main pipe network and along the laterals and effects of plugged or worn nozzles are accounted for. Pratically any type of nozzle and pump can be simulated since cubic spline functions are used to interpolate values from head-flow rate sets of data. Algorithms were developed and adapted to convert laterals into a single set of head-flow rate data so that a simplified algorithm can be used to solve the entire pipe network. A user-friendly interface is used to allow data for pumps, nozzle and pressure regulators to be interactively entered, edited and analyzed. The layout of the irrigation system is drawn on screen using the mouse