S. K. Kor

Pseudo-Grüneisen parameter for liquid argon

Abstract The pseudo-Gruneisen parameter Γ, characterising the lattice behaviour of liquids, has been evaluated for liquid argon at temperatures ranging from 100 to 150°K and pressure from 10 to 500 atm. The parameter is found to fall with increase in temperature and at high pressures, the liquid starts behaving like a solid.

Ultrasonic attenuation in cesium halides

The attenuation of longitudinal ultrasonic waves originating from their interaction with phonon gas and from other thermoelastic causes has been evaluated in CsCl, CsBr, and CsI at 300°K by using second‐order elastic moduli and third‐order elastic moduli, in the 〈100〉 and 〈110〉 directions, and shear waves polarized along the 〈100〉 and 〈110〉 directions. The phonon viscosity and dislocation drag along the 〈100〉 and 〈110〉 directions are also discussed.

Ultrasonic attenuation in GaAs and InSb

Second−and third−order elastic moduli have been used to evaluate the attenuation suffered by compressional and shear acoustic waves propagating along 〈100〉 and 〈110〉 directions and shear waves polarized along 〈100〉, 〈110〉, and 〈001〉 directions for GaAs and InSb, due to phonon viscosity and thermoelastic phenomena at 298 °K. The Gruneisen mode 〈γ〉, the average square Gruneisen 〈γ2〉, nonlinearity constant D, phonon viscosity, and the dislocation drag along 〈100〉 and 〈110〉 directions are also discussed.

Study of phonon−phonon interaction and electron−lattice interaction in alkali metals

Second− and third−order elastic constants have been used to evaluate the ultrasonic attenuation suffered by longitudinal waves propagating along 〈100〉 and 〈110〉 directions and by shear waves polarized along 〈100〉 and 〈110〉 directions for lithium, sodium, potassium, rubidium, and cesium, through the Gruneisen constant 〈γ〉, the average square Gruneisen constant 〈γ2〉, and the nonlinearity constant D, due to phonon viscosity (Akhieser loss) and thermoelastic phenomena at 300 °K. The Akhieser loss is found to be the dominating one. In metals, both electrons and phonons carry thermal energy, but in equilibrating the phonon temperature only the thermal energy carried by phonons comes into play. Hence all the evaluations except the thermoelastic loss have been made by separating the lattice conductivity from the electronic conductivity. Phonon viscosity and both types of dislocation drag coefficients (screw and edge) are also discussed. Moreover, the low−temperature ultrasonic attenuation due to electron−lattice...

Ultrasonic attenuation in aluminium

Abstract Second- and third-order elastic-constant data have been used to determine the Gruneisen mode, 〈γ〉, average-square Gruneisen constant, 〈γ 2 〉 and nonlinearity constant D , for Aluminium. The attenuation suffered by longitudinal ultrasonic wave propagating in 〈100〉 and 〈110〉 directions and shear wave polarized along 〈100〉 and 〈1 1 0〉 directions, due to phonon viscosity and thermoelastic phenomena have been evaluated from two different values of TOEM at 289°K and comparison with observed experimental results has been made also.

Pressure dependence of ultrasonic absorption and compressional viscosity due to structural rearrangement in hexane and toluene

SummaryHirai and Eyring’s notion of holes in a liquid lattice has been employed to demonstrate the effect of pressure on the various contributions to the total ultrasonic absorption in toluene and hexane in the pressure range (1⧀v10000) kg/cm2. Under some specific assumpons, the pressure dependence of the thermal relaxation time for these Kneser-type liquids has also been exploited.RiassuntoSi è usato il concetto di buche in un reticolo liquido dovuto a Hirai ed Eyring per dimostraıe l’effetto della pressione sui vari contributi all’assorbimento ultrasonico totale nel toluene e nell’esano nel campo di pressioni (1⧀v10000) kg/cm2. Facendo alcune ipotesi specifiche, si è anche sfruttata la dipendenza del tempo di rilassamento termico della pressione per questi liquidi del tipo di Kneser.РезюмеБыло использовано описание Хирея и Иринга дырок в жидкой решетке для исследования влияния давления на различные вклады в полное ультразвуковое поглощение в толуоле и гексане в области давлений от 1 до 10000 кг/см2. С помощью некоторых специальных предположений была также изучена зависимость от давления времени тепловой релаксации t для этих жидкостей, кнесеровского типа.

ULTRASONIC STUDY IN BINARY MIXTURES OF WATER AND HEAVY WATER.

SummaryAn experimental study of ultrasonic absorption in water and heavy-water mixtures has been made at three concentrations from 10 to 50 ‡C. Because of the close similarities in the behaviour of the aforesaid components an ideal mixing has been assumed. To explain the excess absorption, Hall’s two-state model of structural absorption has been used. The results are as expected, and the experimentally observed excess and the theoretically calculated structural absorption are in close agreement with each other in the present temperature range. The values δV/V = 0.47 and Β∞ = 17·10−12 cm2/dyn have been assumed for computations.RiassuntoSi è eseguito uno studio sperimentale dell’assorbimento ultracustico neue miscele di acqua ed acqua pesante a tre concentrazioni tra 10 e 50 ‡C. A causa delle strette somiglianze nel comportamento dei suddetti componenti si è supposta una miscelazione ideale. Per spiegare l’eccesso di assorbimento si è usato il modello a due stati di Hall per l’assorbimento strutturale. I risultati sono quelli attesi e l’eccesso osservato sperimentalmente e 1’assorbimento strutturale calcolato teoricamente sono in stretto accordo l’uno eon l’altro nell’attuale intervallo di temperature. Per i calcoli si sono adottati i valori δV/V = 0.47 e Β∞ = 17·10−12 cm2/dyn.РЕжУМЕБылО пРОВЕДЕНО ЁкспЕ РИМЕНтАльНОЕ ИсслЕДОВАНИЕ УльтРА жВУкОВОгО пОглОЩЕНИь В сМЕсьх В ОДы И тьжЕлОИ ВОДы пРИ тРЕх кОНцЕНтРАцИьх От 10‡ ДО 50 ‡с. ВслЕДстВИЕ тЕсНОгО с хОДстВА В пОВЕДЕНИИ ВышЕУпОМьНУтых кОМп ОНЕНт, БылО пРЕДпОлОж ЕНО ИДЕАльНОЕ сМЕшИВАНИ Е. Дль ОБЩьсНЕНИь ИжБы тОЧНОгО пОглОЩЕНИь БылА ИспОльжОВАНА МОДЕль хОллА с ДВУМь сОстОьН ИьМИ Дль стРУктУРНОгО пОглОЩ ЕНИь. В РАссМАтРИВАЕМОИ ОБ лАстИ тЕМпЕРАтУР ЁкспЕРИМЕНтАльНО НА БлУДЕННОЕ ИжБытОЧНО Е пОглОЩЕНИЕ И тЕОРЕтИ ЧЕскИ ВыЧИслЕННОЕ ст РУктУРНОЕ пОглОЩЕНИЕ сОглАсУУ тсь ДРУг с ДРУгОМ. Дль ВыЧИслЕН ИИ БылИ пРЕДпОлОжЕНы жНАЧЕНИь ВЕлИЧИН δV/V =0.47 И Β∞=17·1012 сМ2/ДИН.

Phonon viscosity and dislocation drag in GaSb and CdS

Abstract Phonon viscosity, dislocation drag of both types (screw and edge) and attenuation caused by phonon-phonon interaction and thermoelastic loss have been discussed with the help of SOEM and TOEM for GaSb and CdS along different directions of propagation and polarisation at 295 K using the Akhieser and Mason approaches.

Volume viscosity and structure of D2O using ultrasonics

Abstract Halls theory of structural relaxation has been applied to calculating two adiabatic volume viscosities ηv and η′v, the mole fraction in the open packed state x2 and the relaxational thermal expansion βr of D2O in the temperature range 5 to 50 °C. The values KT, ∞ = 17 × 10-12 cm2/dyn and ΔV/V = 0.47 have been taken for computation. The results agree fairly well at low temperatures with those available for H2O and D2O. The value of thermodynamical parameters give support to Halls two state model upto 10 °C.

Ultrasonic absorption in 1-1 electrolytes

Abstract Ultrasonic absorption measurements have been made in some halides of Li, Na and K in 50% glycolwater mixture at 25°C in the frequency region 30 Mcs using pulswe technique. The absorption α f 2 is found to be frequency independent for all the salts studied and is, in general, lower than of the solvent. The depression in absorption is found to increase in the order — chloride, bromide and iodide — the same order or variation as found in Raman spectral shifts of water caused by alkali halides. A qualitative interpretation of the present results and also of Tamm,s results in water is given.