The pressure dependence of the Grüneisen parameter can be determined by the measurement of temperature changes associated with adiabatic compression using the thermo‐dynamic relationship γ = Bs/T (∂T/∂P)s. Bs, the adiabatic bulk modulus, is known from ultrasonic measurements. The measurement of (∂T/∂P)s is carried out in an end‐loaded piston cylinder apparatus at pressures up to 35 kbar using a fluid cell. Results are presented for a series of fluids, metals, salts, and minerals. For fluids an increase in γ with pressure is observed. For all solids investigated, γ decreases with pressure. A drastic increase in γ is observed when a substance undergoes a phase transition. We find a systematic behavior of (∂T/∂P)s versus volume except for minerals. The average value of q = −(∂ℓ nγ/∂ℓ nV)T is 1.3. The value of γ for iron at a compression equivalent to the core mantle boundary is discussed, but the uncertainties are too large to permit us to predict with confidence γ for iron at the temperatures and pressures of the core.

SummaryThe silanization/hydrosilation bonding method is tested on both a laboratory synthesized and commercial titania. The laboratory titania made by the sol-gel process shows evidence of residual organic material that is removed by an initial acid hydolysis followed by bonding of the hydride (triethoxysilane) under acidic conditions. DRIFT and solid state CP-MAS NMR studies are used to confirm the formation of the hydride layer on the titania and the success of the hydrosilation process for attaching an organic moiety (1-octadecene) to the surface. Chromatographic testing, primarily on the commercial titania based C-18 phase, indicates good reverse phase properties and few residual OH groups, either Ti-OH or Si-OH, as determined by the symmetrical peak shapes obtained for anilines and alkylphenylamines using mobile phases with no buffers or masking agents in the aqueous component.

Changes of sample temperature associated with small adiabatic pressure changes were measured for the metals aluminum, copper, indium, iron, and lead, and the thermodynamic GrUneisen parameter ¾ is calculated from the relation y--(Ks/T) (•T/•P)s where K s is the adiabatic bulk modulus. Measurements were carried out to 33 kbar under hydrostatic conditions in a fluid cell with Bridgman's unsupported seals using an end-loaded piston cylinder apparatus.

The behavior of electrical resistivity in the critical region of three polar + nonpolar binary liquid systems CS2 +(CH3CO)2O, C6H12+(CH3CO)2O, and n-C7H16+(CH3CO)2O is studied. For the mixtures with critical composition, the two phase region shows a conductivity behavior with σ1−σ2∼ (−ε)β with β?0.35. In the one phase region dR/dT has a singularity ε−b with b?0.35. A possible theory of the impurity conduction is given, which broadly explains these results. The possibility of dR/dT being positive or negative is also discussed.

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