Reply to a comment by S.N. Semenov and M.E. Schimpf on ‘Role of the velocity frame of reference in thermodiffusion in liquid mixtures’, Philosophical Magazine vol. 92, 705 (2012), by M. Eslamian,C.G. Jian and M.Z. Saghir.

A small angle X-ray scattering (SAXS) study of nanovoids in 99.988 and 99.995?at.% aluminium is presented. Absolute intensity calibration using a glassy carbon standard is used to extract the weak SAXS signature from nanovoids introduced by thermal quenching. SAXS analysis methods, including Guinier, Porod and Indirect Transform, are used to obtain values for the void–size, number distribution and volume fraction, as well as measures of the void-metal matrix interface structure in quenched aluminium samples. The SAXS analysis has identified a residual impurity effect on void formation and has been used to characterize trends in nanovoid size, number distribution and interface structure as a function of ageing time at elevated temperatures (artificial ageing). The work presented here, including identification of experimental tools that can be readily improved, demonstrates that SAXS studies are capable of providing precise characterization of nanovoid structure in aluminium. This level of information will be useful in developing phenomenological models of void nucleation and growth capable of linking atomic scale phenomena to macroscopic material properties.     

Comment on “Role of the velocity frame of reference in thermodiffusion in liquid mixtures” by M. Eslamian,C.G. Jiang and M.Z. Saghir

We analyze the material transport equations (MTE) derived by Eslamian and co-authors and address the criticism expressed regarding the approach formulated in our previous work. In doing so, we show that the MTE formulated by Eslamian and co-authors are valid only in closed stationary non-isothermal systems in combination with the restrictions on the Onsager coefficients formulated in our work which is criticized, and that for non-stationary systems the approach we took can be used.     

Reply to the Commentary by E.M. Terentjev and M. Warner on “Mechanical properties of mono-domain side-chain nematic elastomers”

We argue that all dynamic mechanical experiments on side-chain liquid-crystalline elastomers performed up to now can be described without invoking the picture of dynamic soft or semi-soft elasticity.Received: 18 June 2004, Published online: 24 August 2004PACS: 83.80.Va Elastomeric polymers - 61.30.-v Liquid crystals - 83.60.Bc Linear viscoelasticity     

Kinetic study of the thermal transformation of limonite to hematite by X-ray diffraction, ��-Raman and M?ssbauer spectroscopy

A kinetic study about the phase limonite (FeO(OH)-nH₂O) was performed through X-ray diffraction, ??-Raman spectroscopy and Mössbauer spectroscopy. The oxide powder sample was extracted from Taraco district, Huancané province of Puno (Peru). X-ray diffraction identified the phase goethite as the main mineralogical component, and then the sample was subjected to in-situ heat treatment in the temperature range: 100 to 500°C in oxidizing (air) and inert (nitrogen) atmospheres. The goethite phase remains stable in this range: room temperature to 200°C. Between 200°C to 250°C there is a phase transition: ??-Fe^3?+?O(OH) ?? ??-Fe₂O₃, i.e., from goethite to hematite phase, taking as evidence the evolution of the diffraction profiles. At 200°C spectra shows the start of broadened magnetic component and it was adjusted through of a magnetic distribution giving a mean field of 38.6T and a relative area of 52.9%, which is a characteristic of goethite. Also, it is noticed the presence of a small amount of hematite with a mean field of 49.0T linked with a superparamagnetic broadened doublet of relative area of 47.1% where the domains of the particles have sizes smaller than 100 Å and it is evidence the superparamagnetic limit; i.e., the superparamagnetic effect tends toward a distribution of magnetic fields. Moreover, the Raman spectra of the in-situ thermal treatment, support the transition at 290°C through the transformation of characteristic bands of goethite to hematite phase at the frequency range from 200 to 1,800 cm^???1.     

Dust in the Universe – Similarities and Differences,by K.S. Krishna Swamy

A simple microscopic deduction of Archimedes' principle as applied to gases is given in terms of the kinetic theory, and some conventional explanations of barometric effects are queried.     

Comment on¶“On the relationship between the entropy and enthalpy of interfacial segregation” by L. Rubinovich and M. Polak

The paper of L. Rubinovich and M. Polak [Eur. Phys. J. B 22, 267 (2001)] contains some controversial items. The notation “excess” in connection with various thermodynamic quantities describing solute segregation on the basis of the Langmuir-McLean isotherm is used in a meaning contradictory to general thermodynamics. The approach used to interpret the linear relationship between segregation entropy and enthalpy results in rather strange conclusions. These items are discussed, and it is shown how a formulation with standard terms is in accordance with general thermodynamics. Received 14 January 2002 / Received in final form 27 September 2002 Published online 14 February 2003 RID="a" ID="a"e-mail: lejcekp@fzu.cz     

Reply to “on one of the ways of application of the lattice-gas model to describe the kinetics of desorption” by V.P. Zhdanov

Zhdanov's criticism on the applicability of our desorption rate which is proportional to the factor θ/(1−θ), where θ is the surface coverage, is shown to be irrelevant. To be precise, the difference between our and former conventional transition state theory is clarified. Also, the differences between our model and the precursor model are stressed, although these two models result in a similar desorption rate.     

Separation of Contributions of the Magnetic Relaxation and Diffusion of Nanoparticles in Ferrofluids by Analyzing the Hyperfine Structure of Mössbauer Spectra

The theory and method for analysis of Mössbauer spectra of magnetic nanoparticles in a fluid have been developed by generalizing the model of the magnetic dynamics of a Néel ensemble of antiferromagnetic particles to the case of ferrimagnetic iron oxides. The resulting model describing the “superposition” of the magnetic dynamics and translational motion of nanoparticles in ferrofluids has been tested in application to the simultaneous analysis of Mössbauer spectra of “dry” magnetite nanoparticles and the same particles in glycerol.     

Comment on “Foam imbibition in microgravity. An experimental study” by H. Caps,H. Decauwer,M.-L. Chevalier,G. Soyez,M. Ausloos and N. Vandewalle

In a recent paper, [1] described parabolic flight experiments showing the movement of liquid into the foam during the microgravity phase. In this comment, we present a detailed theory of this process, supported by numerical calculations, confirming their conclusion that the wetting front moves with the square root of time. We further show that this diffusion process is similar for different surfactant systems, which allows us to provide bounds on the value of the diffusion coefficient.Received: 28 April 2004, Published online: 3 August 2004PACS: 82.70.Rr Aerosols and foams - 83.80.Iz Emulsions and foams     

Basics of Statistical Physics,by Harald J.W. Müller-Kirsten

Reactor Physics. By R. Schulten and W. Güth. Translated by W. K. Mansfield. In two volumes. (Harrap, 1967.) [Vol. I: pp. viii + 144; Vol. II: pp. vi+ 154.] 22s. 6d. each volume.

Principles of Atomic Spectra. By B. W. Shore and D. H. Menzel. (John Wiley, 1968.) [Pp. xiv + 538.] £8. 18s. 0d.

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Progress in High Temperature Physics and Chemistry. Edited by C. A. Rouse. (Pergamon Press, 1968.) [Pp. 176.] 75s.

Ondes dans las Plasmas. By Daniel Quémada. (Paris: Hermann, 1968.) [Pp. 384.] 48 Fr.

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Ultracold Gases and Quantum Information: Lecture Notes of the Les Houches Summer School in Singapore,edited by C. Miniatura,L-C. Kwek,M. Ducloy,B. Grémaud,B-G. Englert,L.F. Cugliandolo,A. Ekert and K. K. Phua

Measurements of the Faraday magneto-optical effect and of optical absorption in magnetic garnet crystals and films are reviewed. Earlier work was restricted to measurements in the visible spectrum; these measurements showed that the transparency was sufficient to allow magnetic domains to be studied in relatively thick slabs. Within the last year or so interest has been renewed in extending magneto-optical measurements beyond the visible spectrum. In particular, extremely low absorptions are found in the wavelength range of approximately 1–5 microns. Thie work is, in no small way, spurred by the possibility of developing a light-beam modulator using the Faraday effect in this wavelength range. Recent measurements at very short wavelengths using garnet films are also reported. By extending the short wavelength measurements to 3000 Å, about two orders of magnitude increase in Fareday rotation and optical absorption are observed, compared with the visible spectrum measurements.

The Faraday effect has been used to measure magnetic hysteresis loops in single-crystal garnet slabs. Magneto-optical observation of the corresponding domain structures shows them to be particularly simple. Detailed correlation of domain structure and hysteresis loops is described; in addition, an estimate of the domain wall energy and its width is made from these measurements.

The garnets referred to in this review are yttrium iron garnet (YIG), gadolinium iron garnet (GdIG), and YIG doped with gallium (YGaIG).