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Knowledge of the optical refractive index structure parameter $C_n^2$ is of interest for Free Space Optics (FSO) and ground-based optical astronomy, as it depicts the strength of the expected scintillation on the received optical waves.…

Signal Processing · Electrical Eng. & Systems 2023-01-24 Florian Quatresooz , Danielle Vanhoenacker-Janvier , Claude Oestges

Linear dielectric thermodynamics are formally developed to explore the isothermal and adiabatic temperature - pressure dependence of dielectric constants. The refractive index of optical materials is widely measured in the literature: it is…

Materials Science · Physics 2023-11-15 S. J. Burns

Aims: We systematically explore a plausible subset of the parameter space involving effective temperatures and metallicities of the ionizing stellar sources, the effects of the hardening of their radiation by surrounding leaky HII regions…

Astrophysics of Galaxies · Physics 2019-02-13 J. A. Weber , A. W. A. Pauldrach , T. L. Hoffmann

We describe a simple and robust method using an internal reflection element acting as an infrared waveguide to measure the spectra of near-field thermal emission. We experimentally demonstrate the spectrally-narrow peaks of near-field…

Instrumentation and Detectors · Physics 2020-01-01 Saman Zare , Carl Tripp , Sheila Edalatpour

Two ultracompact H II regions (IRAS 19181+1349 and 20178+4046) and one compact molecular clump (20286+4105) have been observed at far infrared wavelengths using the TIFR 1 m balloon-borne telescope and at mid infrared wavelengths using ISO.…

Astrophysics · Physics 2009-11-07 R. P. Verma , S. K. Ghosh , B. Mookerjea , T. N. Rengarajan

In order to explain the positive temperature coefficient of the visible index of refraction of fused silica I develop a simple model which assumes a single ultraviolet resonance. Assuming thermal broadening and using the Kramers- Kronig…

Materials Science · Physics 2009-10-30 J. I. Katz

The fluorescence detection of ultra high energy cosmic rays requires a detailed knowledge of the fluorescence light emission from nitrogen molecules over a wide range of atmospheric parameters, corresponding to altitudes typical of the…

Astrophysics · Physics 2019-08-13 M. Ave

A surprisingly good holographic description of QCD can be obtained from naive five dimensional gauge theory on a truncated AdS space. We seek to improve the infra-red description of QCD in such models by using a more sophisticated metric…

High Energy Physics - Phenomenology · Physics 2010-10-27 Nick Evans , Andrew Tedder , Tom Waterson

We propose a realistic model of the optical properties of silver, in which inter-band transition with a threshold energy of ~ 4 eV is described phenomenologically by an ensemble of oscillators with same damping constant and a certain…

Materials Science · Physics 2013-12-12 Armen Melikyan , Boris Kryzhanovsky

Long-wave infrared radiation captured by a thermal camera includes (a) emission from an object governed by its temperature and emissivity, and (b) reflected radiation from the surrounding environment. Separating these components is a…

Computer Vision and Pattern Recognition · Computer Science 2026-03-31 Sriram Narayanan , Mani Ramanagopal , Srinivasa G. Narasimhan

We describe the Cool Opacity-sampling Dynamic EXtended (CODEX) atmosphere models of Mira variable stars, and examine in detail the physical and numerical approximations that go in to the model creation. The CODEX atmospheric models are…

Astrophysics · Physics 2009-11-13 M. J. Ireland , M. Scholz , P. R. Wood

The determination of chemical abundances in ionized gas nebulae is based on the detection of auroral emission lines, from which it is possible to deduce the line temperatures of several ions. These lines are weak in low excitation objects,…

Astrophysics · Physics 2007-05-23 Enrique Perez-Montero , Marcelo Castellanos , Angeles I. Diaz

This work focuses on determining the coefficient of thermal diffusivity in a one-dimensional heat transfer process along a homogeneous and isotropic bar, embedded in a moving fluid with heat generation. A first type (Dirichlet) condition is…

Fluid Dynamics · Physics 2022-01-03 Guillermo Federico Umbricht , Diana Rubio

A solar photospheric "thermal profiling" analysis is presented, exploiting the infrared rovibrational bands of carbon monoxide (CO) as observed with the McMath-Pierce Fourier transform spectrometer (FTS) at Kitt Peak, and from above the…

Astrophysics · Physics 2009-11-11 Thomas R. Ayres , Claude Plymate , Christoph U. Keller

Recent analyses of the intergalactic UV background by means of the HeII Lyman alpha forest assume that HeII and HI absorption features have the same line widths. We omit this assumption to investigate possible effects of thermal line…

Astrophysics · Physics 2009-11-11 C. Fechner , D. Reimers

Condensation and sublimation of water vapors (and CO2, CH4, N2O vapors also) in the Earth atmosphere must be accompanied by emission of latent heats on characteristic frequencies marked in absorption spectra. Calculated wave lengths…

Atmospheric and Oceanic Physics · Physics 2009-05-06 Mark E. Perel'man

Dust infrared emission possesses scaling properties. Overall luminosity is never an input parameter of the radiative transfer problem, spectral shape is the only relevant property of the heating radiation when the inner boundary of the…

Astrophysics · Physics 2015-06-24 Zeljko Ivezic , Moshe Elitzur

We present long-slit spectrophotometric observations in the red and near infrared of 12 HII galaxies. The spectral range includes the sulphur lines [SII] at wavelengths 6716, 6731 angstroms and [SIII] at 6312 angstroms and 9069, 9532…

Astrophysics · Physics 2009-11-10 Enrique Perez-Montero , Angeles I. Diaz

The laser flash method for measuring thermal diffusivity of solids involves subjecting the front face of a small sample to a heat pulse of radiant energy and recording the resulting temperature rise on the opposite (rear) surface. For the…

Computational Physics · Physics 2019-09-18 Elliot J. Carr

Using the Cryogenic, High-Accuracy Refraction Measuring System (CHARMS) at NASA's Goddard Space Flight Center, we have measured the absolute refractive index of five specimens taken from a very large boule of Corning 7980 fused silica from…

Optics · Physics 2008-05-02 Douglas B. Leviton , Bradley J. Frey
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