Applied Science Private University

About: Applied Science Private University is a education organization based out in Amman, Jordan. It is known for research contribution in the topics: Population & Catalysis. The organization has 4124 authors who have published 5299 publications receiving 116167 citations.

Complementarity Relation for Irreversible Process Derived from Stochastic Energetics

Abstract: When the process of a system in contact with a heat bath is described by the classical Langevin equation, use of the method of stochastic energetics [K. Sekimoto: J. Phys. Soc. Jpn. 66 (1997) 1234] enables us to derive the form of Helmholtz free energy and the dissipation function of the system. We are able to prove that the irreversible heat Q irr and the time lapse Δ t of an isothermal process obey the complementarity relation, Q irr Δ t ≥ k B T S min , where S min depends on the initial and the final values of the control parameters, but does not depend on the pathway between these values.

Dust-bounded ultraluminous infrared galaxies: model predictions for infrared spectroscopic surveys

Abstract: The observed faintness of infrared fine-structure line emission along with the warm far-infrared (FIR) colors of ultraluminous infrared galaxies (ULIRGs) is a long-standing problem. In this work, we calculate the line and continuum properties of a cloud exposed to an active galactic nucleus (AGN) and starburst spectral energy distribution. We use an integrated modeling approach, predicting the spectrum of ionized, atomic, and molecular environments in pressure equilibrium. We find that the effects of high ratios of impinging ionizing radiation density to particle density (i.e., high-ionization parameters, or U) can reproduce many ULIRG observational characteristics. Physically, as U increases, the fraction of UV photons absorbed by dust increases, corresponding to fewer photons available to photoionize and heat the gas, producing what is known as a 'dust-bounded' nebula. We show that high-U effects can explain the '[C II] deficit', the {approx}1 dex drop in the [C II] 158 {mu}m/FIR ratio seen in ULIRGs when compared with starburst or normal galaxies. Additionally, by increasing U through increasing the ionizing photon flux, warmer dust and thus higher IRAS F(60 {mu}m)/F(100 {mu}m) ratios result. High-U effects also predict an increase in [O I] 63 {mu}m/[C II] 158 {mu}m and a gradual decline in [O III]more » 88 {mu}m/FIR, similar to the magnitude of the trends observed, and yield a reasonable fit to [Ne V] 14 {mu}m/FIR ratio AGN observations.« less