We study the effects of the initial conditions of turbulent molecular clouds on the ionization structure in newly formed H ii regions, using three-dimensional, photon-conserving radiative transfer in a precomputed density field from three-dimensional compressible turbulence. Our results show that the initial density structure of the gas cloud can play an important role in the resulting structur...

The dependence of the e€ective secondary electron yield on the potential distribution and the target materials was investigated by means of electron transport simulation in the sheath with the potential distribution calculated for the di€erent emission characteristics of Be (Zˆ 4), C (Zˆ 6), Mo (Zˆ 42) and W (Zˆ 74) as the target materials. For lower primary energy incidence the e€ective second...

A major weakness of the limited memory BFGS (LBFGS) method is that it may converge very slowly on ill-conditioned problems when the identity matrix is used for initialization. Very often, the LBFGS method can adopt a preconditioner on the identity matrix to speed up the convergence. For this purpose, we propose a class of diagonal preconditioners to boost the performance of the LBFGS method. In...

Innovation is critical to our economic and social prosperity. We rely on industry, university, and government employees to develop, modify, and implement innovative ideas while navigating ambiguous problem contexts, overcoming setbacks, and persisting in competition with courses of action. Research has shown that self-efficacy, or individuals’ belief in their ability, influences the pursuit of ...

We present a description of the early-stage dynamics in relativistic heavy ion collisions, where the free-streaming (FS) of partons is followed by a sudden equilibration (SE) to a thermalized phase, providing initial conditions for the subsequent hydrodynamic evolution. This FS+SE approximation has been proposed by Kolb, Sollfrank, and Heinz [1]. It has been further discussed in the context of ...

Limited data feedback rate, e.g. 1-10 samples per second instead of 25-60, causes adverse effect on wide-area damping control (WADC). An observer driven system copy (OSC) approach is suggested here to deal with low data rates. The basic idea is to use the knowledge of nominal system dynamics to approximate the actual system behavior during intervals when data from phasor measurement units (PMUs...

In comparison to the Tatsumi’s spectral method, the harmonic-Fourier spectral method has two major advantages. 1) The semi-implicit scheme is quite efficient because the solutions of the Poisson and Helmholtz equations are readily derived. 2) The lateral boundary value problem of a limited-area model is easily solved. These advantages are the same as those of the spherical harmonics used in glo...

Unreliable failure detectors are oracles that give information about process failures. Chandra and Toueg were first to study such failure detectors for distributed systems, and they identified a number that enabled the solution of the Consensus problem in asynchronous distributed systems. This paper focuses on two of these, denoted S (strong) and 3S (eventually strong). The characteristics of a...