An a.c. calorimetric study has been carried out on octylphenylthiolpentyloxybenzoate (8ÂS5) in three silica aerogels with mass densities r=0 0́8, 0 1́7 and 0 3́6 g cm Õ 3 . Results for the least porous aerogel (r=0 3́6) are completely consistent with those reported previously for 8CB in the same aerogel. Freezing of 8ÂS5 damaged the more porous r=0 0́8 and 0 1́7 aerogels by creating internal voids an...

Silica aerogels functionalized with strongly fluorescent carbon quantum dots were first prepared and used for simple, sensitive, and selective sensing of NO2 gas. In the presence of ethanol, homemade silica aerogels with a large specific surface area of 801.17 m(2)/g were functionalized with branched polyethylenimine-capped quantum dots (BPEI-CQDs) with fluorescence quantum yield higher than 40...

We have investigated the dissipation (Q-1) using the torsion pendulum technique for pure 3He and 3He-4He mixtures in silica aerogel near the 3He superfluid transition (T(c)) in aerogel. With pure 3He the Q-1 decreases at the onset of superfluidity. When phase separated 3He-4He mixtures are introduced into the aerogel, the Q-1 does not decrease as rapidly and eventually increases for the highest...

Reported silica aerogels have a thermal conductivity as low as 15 mW/mK. The fragility of silica aerogels, however, makes them impractical for structural applications. The purpose of the study is to improve the ductility of aerogels while retain the low thermal conductivity of silica aerogels. We have established a new synthesis route, a 3-step sol-gel processing method. The method provides bet...

Phenol-formaldehyde/silica hybrid gel with hydrophobic character, high porosity, and thesmall pore size mean was prepared via sol-gel polymerization under solvent saturated vaporatmosphere and was dried by ambient drying method. The silica sols were prepared based onTetraethoxysilane (TEOS) and Methyltrimethoxysilane (MTES) as hydrophilic and hydrophobicprecursors, respectively. Phenol-formalde...

Silica aerogels are popular in terms of production volume and real-world applications. Although the current market growth rate is driven exclusively by thermal insulation, may also be attractive for acoustic applications with potential aiding sound absorption/insulation. This paper a summary acoustics related studies silica aerogel-based products. It introduces aerogels, some characterization m...

G. Lawes,1 S. C. J. Kingsley,1,* N. Mulders,2 and J. M. Parpia1 1Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 2Department of Physics and Astronomy, University of Delaware, Newark, Delaware (Received 15 December 1999) We have investigated the superfluid transition of 3He in different samples of silica aerogel. By comparing new measurements on a 99.5% sample ...

Introduction: The hypervelocity impacts of comet particles at 6.1 km/s have left tracks in the Stardust aerogel. The terminal particles are usually coarse grained minerals but abundant material is also present along the track walls as illustrated by synchrotron X-rays fluorescence spectroscopy [1]. This configuration suggests that the Wild 2 particles are made of poorly cohesive assemblages tha...

Silica aerogel possesses an ultra-low thermal conductivity by virtue of its nano-structure. Owing to the fragility monolithic aerogel, development and production aerogel-based insulation materials involve incorporation granular with other form composite materials. In present study, application silica-aerogel-incorporated cement paste as render on roof-top surface is coupled installation a novel...