Ultrasonic studies

The piezoelectric constant studies are perhaps the most unique of the shock studies in the elastic range. The various investigations on quartz and lithium niobate represent perhaps the most detailed investigation ever conducted on shock-compressed matter. The direct measurement of the piezoelectric polarization at large strain has resulted in perhaps the most precise determinations of the linear constants for quartz and lithium niobate by any technique. The direct nature of the shock measurements is in sharp contrast to the ultrasonic studies in which the piezoelectric constants are determined indirectly as changes in wavespeed for various electrical boundary conditions. 

An ultrasonic study of the zinc and cadmium complexes of ILedta has demonstrated a dynamic equilibrium in solution interconverting the pentadentate and hexadentate forms in solution.121 ... 

Cluster Theories. Historically, the most important study of water structure based on the existence of clusters was Stewart s x-ray diffraction work (142). In his theory, clusters ( cybotactic swarms ) were postulated to exist, each containing on the order of 10,000 water molecules. Although this constituted an apparently reasonable theory at the time, this view has now yielded to the concept of clusters of considerably smaller sizes. It is interesting to note that without much critical analysis, Frenkel (57) viewed Stewart s theory of water as essentially correct. In fact, Frenkel apparently expected that further work on liquid structures in general would be along the lines Stewart advocated. Luck has discussed this in some detail (100). Subsequent to Stewart s papers, Nomoto (113) discussed a water model, based on ultrasonic studies, involving clusters of several thousand water molecules. 

Nagata, K., Tagashiva, K., Taki, S. and Takemura, T. Ultrasonic study of high pressure phase in polyethylene, Japan. J. Appl. Physics 19, 985 (1981)... 

Pavlovskaya, G.E., McClements, D.J., Povey, M.J.W. 1992b. Ultrasonic studies of aqueous salt solutions of a globular protein. In Developments in Acoustics and Ultrasonics (M.J. W. Povey, D.J. McClements, eds.), pp. 243-246, Institute of Physics Publishing, Bristol. 

Similarity of 34 values for complexation between Mg2+ and SO2-, Cr02 and S2C) and solvent exchange rates of paramagnetic ions to the 34 values obtained by the present ultrasonic studies give evidence for a dissociative type of mechanism. The removal of a water molecule from the solvated lanthanide in step 3 is probably the rate-determining step. We may then write... 

Pathological, angiographic and ultrasonic studies show that the most common extracranial sites for atheroma are the aortic arch, the proximal subclavian arteries, the carotid... 

Audebrand, M., Kolb, M., and Axelos, M. A. V. 2006. Combined rheological and ultrasonic study of alginate and pectin gels near the sol-gel transition. Biomacromolecules 7( 10) 2811-2817. 

Ultrasonics is in many ways the ideal measurement method for fat crystallization studies. The ultrasonic properties of a fat are strongly sensitive to solids content and can be measured in opaque fats and through container walls. In the present work I will describe the basic physics of ultrasonic waves, their interactions with matter (particularly with semi-solid fats), and their measurement. I will then describe ultrasonic studies of fat crystallization in bulk and emulsified fats. Finally I will use some measurements of the effect of applied shear on fat crystallization as an illustration of a study that could not be easily undertaken by other methods. 

Ultrasonic velocity has been almost exclusively measured in ultrasonic studies of fat crystallization, but the attenuation coefficient also can reveal interesting information. As the sound wave passes, the fluid is alternately compressed and rarefied which results in the formation of rapidly varying temperature gradients. Heat energy is lost because the conduction mechanisms are inefficient (thermal losses) and together with molecular friction (viscous losses) cause an attenuation of the sound given by classical scattering theory (5) ... 

Ltithi B, Rehwald W (1981) Ultrasonic studies near stmctural phase transitions. In KA Muller, H Thomas (eds) Stmctural Phase Transitions I. Topics in Current Physics 23 131-184. Springer Verlag, Berlin, Heidelberg, New York... 

Pena L, Junquera E, Aircart E. Ultrasonic study of the molecular encapsulation and the micellization processes of dodecylethyldimethylammonium bromide-water solutions in the presence of /3-cyclodextrin or 2,6-di-o-methyl-/3-cyclo-dextrin. J Solution Chem 1995 24 1075-1091. 

Diverse investigations of the miscellaneous ternary systems Sn-Pb-Cd, Sn-Ga-In, Sn-Sb-Bi, " Pb-In-Sb, and Pb-Bi-Hg have been undertaken by a number of Russian authors. It was concluded from the results of an ultrasonic study of Sn-Pb-Cd liquid solutions that intermetallic compounds are not formed in this system. Thermodynamic analysis of the Sn-Sb-Bi system shows both positive and negative deviations from ideality in the liquid state.Finally, interpretation of the atomic distribution functions of Pb-In-Sb solutions has led to the conclusion that the melts have a microheterogeneous structure in the fusion... 

The two gray-shaded areas in Figure 2.12 mark two frequency bands typical for ultrasonic studies on sediment cores (50 - 500 kHz) and sediment echosounder surveys (0.5 - 10 kHz). They are displayed in order to point to one characteristic of acoustic measurements. Attenuation coefficients analyzed from ultrasonic measurements on sediment cores cannot directly be transferred to... 

An ultrasonic study of the solvation of inter alia potassium thiocyanate in DMF has shown the solvation number of the solute to be one this is in accord with the formation of a solute-solvent complex involving one mole of each constituent. 

An ultrasonic study of aqueous solutions of alkaline-earth-metal salts has been undertaken." The observations suggest that the stability of the solvated structures depends on the capacity of the ions for hydration and complex formation, their dimension, and their shape. 

Ultrasonic studies of the complexation of Li by 12C4 and other crown ethers in 1,3-dioxalane are consistent with the Eigen-Winkler mechanism given in equation (11), where Li is only partially complexed in Li 12C4 and complexation... 

Diagnostic ultrasound based on sonar technology became so widely accepted that ultrasonic studies are now part of the routine diagnostic workup in many medical specialties. 

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