We thoroughly and critically review studies reporting the real (refractive index)
 and imaginary (absorption index) parts of the complex refractive index of silica glass
 over the spectral range from 30 nm to 1000 μm The general features of the optical
 constants over the electromagnetic spectrum are relatively consistent throughout the
 literature In particular, silica glass is effectively opaque for wavelengths shorter
 than 200 nm and larger than 35-40 μm Strong absorption bands are observed (i) below
 160 nm due to the interaction with electrons, absorption by impurities, and the presence
 of OH groups and point defects; (ii) at ~273-285, 35, and 43 μm also caused by OH
 groups; and (iii) at ~9-95, 125, and 21-23 μm due to SiOSi resonance modes of
 vibration However, the actual values of the refractive and absorption indices can vary
 significantly due to the glass manufacturing process, crystallinity, wavelength, and
 temperature and to the presence of impurities, point defects, inclusions, and bubbles,
 as well as to the experimental uncertainties and approximations in the retrieval
 methods Moreover, new formulas providing comprehensive approximations of the optical
 properties of silica glass are proposed between 7 and 50 μm These formulas are
 consistent with experimental data and substantially extend the spectral range of 021-7
 μm covered by existing formulas and can be used in various engineering applications

/pdf/optical-constants-of-silica-glass-from-extreme-ultraviolet-2d35kotg3x.pdf

Optical constants of silica glass from extreme ultraviolet to far infrared at near room temperature.

Advanced models of fuel droplet heating and evaporation

Nanofluids—a simple product of the emerging world of nanotechnology—are suspensions of nanoparticles (nominally 1–100 nm in size) in conventional base fluids such as water, oils, or glycols. Nanofluids have seen enormous growth in popularity since they were proposed by Choi in 1995. In the year 2011 alone, there were nearly 700 research articles where the term nanofluid was used in the title, showing rapid growth from 2006 (175) and 2001 (10). The first decade of nanofluid research was primarily focused on measuring and modeling fundamental thermophysical properties of nanofluids (thermal conductivity, density, viscosity, heat transfer coefficient). Recent research, however, explores the performance of nanofluids in a wide variety of other applications. Analyzing the available body of research to date, this article presents recent trends and future possibilities for nanofluids research and suggests which applications will see the most significant improvement from employing nanofluids.

Small particles, big impacts: A review of the diverse applications of nanofluids

In 1982, the Belgian Pilots' Guild raised the question of what effect exposure to radar radiation--for example, that encountered in passing a pilot launch's radar--might have on the human body. Recapitulating investigations of this question, this article states that in 25 years of experience with radar, there have been no known incidents of pilots being affected by radar waves. In the future, however, involvement by some pilots with Vessel Traffic Service shore-based radar could affect pilots somewhat differently from limited exposure to pilot launch radar. Pilots who find themselves in new working conditions close to an emitting source should exercise care all times.

About heat waves

THE difficulty of reconciling line spectra with the kinetic theory of gases, has been referred to by Prof. Fitzgerald (NATURE, January 3, p. 221). The following considerations show that it is possible under certain suppositions to have a number of spectral rays with a very restricted number of degrees of freedom. Most of us, I believe, now accept a definite atomic charge of electricity, and if each charge is imagined to be capable of moving along the surface of an atom, it would represent two degrees of freedom. If a molecule is capable of sending out a homogeneous vibration, it means that there must be a definite position of equilibrium of the “electron.” If there are several such positions, the vibrations may take place in several periods. Any one molecule may perform for a certain time a simple periodic oscillation about one position of equilibrium, and owing to some impact the electron may be knocked over into a new position. The vibrations under these circumstances would not be quite homogeneous, but if the electron oscillates about any one position sufficiently long to perform a few thousand oscillations, we should hardly notice the want of homogeneity. Each electron at a given time would only send out vibrations which in our instruments would appear as homogeneous. Each molecule could thus successively give rise to a number of spectral rays, and at any one time the electron in the different molecules would, by the laws of probability, be distributed over all possible positions of equilibrium, so that we should always see all the vibrations which any one molecule of the gas is capable of sending out. The probability of an electron oscillating about one of its positions of equilibrium need not be the same in all cases. Hence a line may be weak not because the vibration has a smaller amplitude, but because fewer molecules give rise to it. The fact that the vibrations of a gas are not quite homogeneous, is borne out by experiment. If impacts become more frequent by increased pressure, we should expect from the above views that the time during which an electron performs a certain oscillation is shortened; hence the line should widen, which is the case. I have spoken, for the sake of simplicity, as if an electron vibrating about one position of equilibrium could only do so in one period. If the forces called into play, by a displacement, depend on the direction of the displacement, there would be two possible frequencies. If the surface is nearly symmetrical, we should have double lines.

/pdf/the-kinetic-theory-of-gases-13lklkm24y.pdf

The Kinetic Theory of Gases

The physical basis of the majority of solutions considered in this book is the notion of radiation transfer in an absorbing and scattering medium as some macroscopic process, which can be described by a phenomenological transfer theory and radiative transfer equation for spectral radiation intensity. The book is divided into four chapters. Chapter 1 deals with computational models for radiative transfer in disperse systems. The main attention is given to simple approximate models, both traditional and modified, which have a clear physical sense and enable one to derive some useful analytical solutions to classic problems. Spectral radiative properties of single particles and fibers are considered in some detail in Chapter 2. The theoretical part of this chapter includes the Mie solution for homogeneous spherical particles and more general solutions for hollow and core-mantled spheres. Chapter 3 presents an engineering approach for both theoretical prediction and experimental determination of spectral radiative properties of quite different dispersed materials containing the morphology elements of arbitrary shape. A general theoretical basis of radiative properties determination and present-day principles of experimental characterization with identification procedure are recalled. Physical limitations of independent scattering theory are also discussed in this chapter. Some radiative and combined heat transfer problems in various disperse systems are considered in Chapter 4. For a topic that is as broad as the one considered in this book, it is very difficult to be comprehensive. However, we hope that enough key references are cited in the book to enable an interested reader to undertake a more detailed study of specific thermal radiation problems in disperse systems.
 689 pages, 
© 2010

/pdf/thermal-radiation-in-disperse-systems-an-engineering-mhbnubjm07.pdf

Thermal Radiation in Disperse Systems: An Engineering Approach

A number of technical processes and natural phenomena involve heat transfer by thermal radiation. The physical basis of all solutions considered in this book isthe notion considered in this book is the notion of radiation transfer in an absorbing and scattering medium as a macroscopic process which can be described by a phenomenological transfer theory and kinetic equations for spectral radiation intensity. In addition to covering approximate methods for the solution of the radiation transfer equation, the book discusses radiative properties of some disperse systems, and radiative and combined heat transfer problems. The appendix includes computer codes for studying the methods discussed in the book.
"This reviewer found Radiation Heat Transfer in Disperse Systems to be very interesting and useful. The extensive comparisons between approximate and exact solutions, combined with the physical explanations for the differences, provide important insights into the complexities and subtleties of this subject. It serves as an excellent reference volume for this specific topic."
-Applied Mechanics Reviews
 
256 pages, © 1996

/pdf/radiation-heat-transfer-in-disperse-systems-2j9lixs7zx.pdf

Radiation Heat Transfer in Disperse Systems

The paper presents a discussion of the use of both transport approximation for scattering phase function and diffusionbased models for radiative transfer in absorbing and anisotropically scattering media like many disperse systems in nature and engineering. The main attention is paid to heat transfer problems and traditional methods of identification of spectral radiative properties of dispersed materials when the details of angular distribution of the radiation intensity are not so important. The latter makes reasonable use of the above-mentioned approximations. In more complex applied problems, the diffusion approximation appears to be a good approach as the first step of a combined two-step solution. Some example problems solved recently by the author and his colleagues are used to illustrate the approach considered in the paper.

Leonid A. Dombrovsky

Papers

Thermal Radiation in Disperse Systems: An Engineering Approach

Radiation Heat Transfer in Disperse Systems

The use of transport approximation and diffusion-based models in radiative transfer calculations

A combined transient thermal model for laser hyperthermia of tumors with embedded gold nanoshells

Indirect heating strategy for laser induced hyperthermia: An advanced thermal model