Polycyclic aromatic hydrocarbons (PAHs) are known to be present in many astrophysical objects and environments, but our understanding of their formation mechanism(s) is far from satisfactory. In this paper, we describe an investigation of the catalytic conversion reaction of acetylene gas to PAHs over pyroxene and alumina. Crystalline silicates such as pyroxenes (with general formula [Mg, Fe]Si...

The silver toughened alumina ceramics, which were fabricated via a conventional ceramic processing route using commercially available alumina and silver oxide powders as the starting materials, exhibit a higher fracture toughness (6 to 9 MPamo.5) than the monolithic alumina ceramic ( 2.5 to 3.0 MPamo.5). The weak interfacial bonding between the silver inclusions and the alumina matrix is charac...

In the present study, porous alumina/silica materials were prepared by selective leaching of silicon/aluminum constituents from thermal-activated kaolinite in inorganic acid or alkali liquor. The correlations between the characteristics of the prepared porous materials and the dissolution properties of activated kaolinite were also investigated. The results show that the specific surface area (...

Superhydrophobic nanoporous anodic aluminum oxide (alumina) surfaces were prepared using treatment with vapor-phase hexamethyldisilazane (HMDS). Nanoporous alumina substrates were first made using a two-step anodization process. Subsequently, a repeated modification procedure was employed for efficient incorporation of the terminal methyl groups of HMDS to the alumina surface. Morphology of the...

Alumina-based nanocomposites reinforced with niobium and/or carbon nanotubes (CNT) were fabricated by advanced powder processing techniques and consolidated by spark plasma sintering. Raman spectroscopy revealed that single-walled carbon nanotubes (SWCNT) begin to break down at sintering temperatures >1150 C. Nuclear magnetic resonance showed that, although thermodynamically unlikely, no Al4C3 ...

Nanotechnology is a rapidly growing industry that has elicited much concern because of the lack of available toxicity data. Exposure to ultrafine particles may be a risk for the development of vascular diseases due to dysfunction of the vascular endothelium. Increased endothelial adhesiveness is a critical first step in the development of vascular diseases, such as atherosclerosis. The hypothes...

BACKGROUND Zirconia was introduced as an alternative to alumina for use in the femoral head. The yttria stabilized zirconia material was improved by adding alumina. We evaluated highly cross-linked polyethylene wear performance of zirconia in total hip arthroplasty. The hypothesis was that alumina stabilized zirconia could decrease highly cross-linked polyethylene wear. METHODS Highly cross-l...

Purpose: The aim of the study is to evaluate color stability a conventional composite resin and bulk-fill resins.
 Material Methods: A total 120 samples 10 mm diameter 2 thickness were prepared from three (Beautifil Bulk-Fill, Filtek One Tetric N-Ceram Bulk-Fill) one (Z250) light cured. Initial measurements made with spectrophotometer. Samples for each randomly divided into 3 groups (black...

Alumina nanotubes (ANTs) with unique fusiform morphologies were synthesized via a simple electrochemical route; the fluctuation of the electronic current density during the anodization process is considered to be the main reason for the formation of such new alumina nanostructures.

A "sandwich" type polyoxometalate catalyst ([MeN(n-C8H17)3]12[WZn3(ZnW9O34)2]) was very efficiently recycled by nanofiltration with almost quantitative retention, using an alpha-alumina supported mesoporous gamma-alumina membrane.