We have calculated the thermal emission spectrum of the dust of comet P/Borrelly (1994l), a short-period comet (Jupiter family), from 3 μm to 14 μm as well as the 10 μm silicate feature in terms of the comet dust model as porous aggregates of interstellar grains. Compared to comet P/Halley dust, the dust grains of P/Borrelly appear to be relatively more processed (more carbonized), less fluffy,...

A siliceous porous material containing nickel was synthesized by means of an intercalation treatment method using a layered sodium octosilicate ilerite as a starting base material. The sodium ions between the crystalline silicate sheets in the octosilicate were exchanged for hydrogen ions in dilute hydrochloric acid, and then the basal spaces between the silicate sheets were extended by introdu...

The purpose of this study was to synthesize biomaterials from daily dental waste. Since alginate impression material contains silica and calcium salts, we aimed to synthesize calcium silicate cement from alginate impression material. Gypsum-based investment material was also investigated as control. X-ray diffraction analyses revealed that although firing the set gypsum-based and modified inves...

A technique for doping of porous films by surface adsorption of ions from aqueous solution is demonstrated. Fabrication of the films by use of the solgel technique gives a nanometer-scale porosity, which provides high doping levels and homogeneity. Doping through a masking layer patterned by photolithography is thus possible. With Pb as a dopant, lead silicate films with refractive indices of 1...

Two different evolutionary types of comets proved by polarimetric and infrared properties of their dust ABSTRACT Aims. We consider polarimetric and thermal-emission properties of comet dust and show how and why they can be used for classification of comets. Methods. We provide a statistical analysis of comet polarimetric, thermal, and orbital characteristics. We perform computer simulations of ...

We model the 10 µm absorption spectra of nonspherical particles composed of amorphous silicate. We consider two classes of particles, compact ones and fractal aggregates composed of homogeneous spheres. For the compact particles we consider Gaussian random spheres with various degrees of non-sphericity. For the fractal aggregates we compute the absorption spectra for various fractal dimensions....

The Stardust mission returned the first sample of a known outer solar system body, comet 81P/Wild 2, to Earth. The sample was expected to resemble chondritic porous interplanetary dust particles because many, and possibly all, such particles are derived from comets. Here, we report that the most abundant and most recognizable silicate materials in chondritic porous interplanetary dust particles...

Nuclear magnetic resonance (NMR) relaxation experimentation is an effective technique for probing the dynamics of proton spins in porous media, but interpretation requires the application of appropriate spin-diffusion models. Molecular dynamics (MD) simulations of porous silicate-based systems containing a quasi-two-dimensional water-filled pore are presented. The MD simulations suggest that th...

The Electrochemical Society Interface • Fall 2001 here has been tremendous recent interest in the design and assembly of porous nanostructured materials.1 Synthetic approaches range from coordination-polymer formation to surfactant-templated alumino-silicate growth to semiconductor nanoparticle aggregation, while functions include chemical catalysis, chemical sensing, energy storage, and energy...