A high-resolution calorimetric study has been made on the smectic-A to nematic phase transition in liquid crystals perturbed by the dispersion of 70-Å-diam silica spheres ~aerosils!. The specific heat peak of this transition decreases in amplitude and shifts to lower temperatures with increasing silica density. However, it remains sharp in comparison to the effects of aerogel confinement at the...

The longitudinal acoustic velocity in silica aerogel is presented as a function of the interstitial gas type and pressure. This was measured using air-coupled ultrasonic transducers configured for differential pulse transit time measurements. The results are interpreted in terms of the thermal relaxation of the acoustic pulse. The microscale temperature oscillations of the gas and solid phases ...

Superfluid He has important implications in studying condensed matter physics, specifically in its phases at very low temperatures. The understanding of these phases not only expands our knowledge of He itself, but is also a paradigm for recently discovered unconventional superconductors such as strontium ruthenate (SrRuO3) and uranium platinum three (UPt3). Superfluid He’s relation to supercon...

Superfluid 3He confined in aerogel offers a unique chance to study the effects of a short mean free path on the properties of a well defined superfluid Fermi liquid with anisotropic pairing. Transport coefficients and collective excitations, e.g. longitudinal sound, are expected to react sensitively to a short mean free path and to offer the possibility for testing recently developed models for...

Charged particle identification at the PANDA experiment will be performed over a wide range of momenta by Čerenkov detectors. One option to identify higher momentum charged particles under small polar angles could be the use of silica aerogels as radiator. Simultaneously, an aerogel Čerenkov counter is being designed for the Kaos spectrometer at the Mainz Microtron MAMI for the discrimination b...

Pore structure and connectivity determine how microstructured materials perform in applications such as catalysis, fluid storage and transport, filtering or as reactors. We report a model study on silica aerogel using a time-of-flight magnetic resonance imaging technique to characterize the flow field and explain the effects of heterogeneities in the pore structure on gas flow and dispersion wi...