The adsorption of piperidine vapor on the hydrated alumina (alpha-Al2O3, corundum) (0001) surface was investigated using vibrational broad bandwidth and scanning sum frequency generation (SFG) spectroscopy. The interfacial vibrational signature in the C-H stretching region of piperidine at the alumina (0001) surface is shown to be a sensitive spectroscopic probe revealing the adsorption mechani...

PURPOSE The purpose of this in vitro study is to examine the effects of a nano-structured alumina coating on the adhesion between resin cements and zirconia ceramics using a four-point bending test. MATERIALS AND METHODS 100 pairs of zirconium bar specimens were prepared with dimensions of 25 mm × 2 mm × 5 mm and cementation surfaces of 5 mm × 2 mm. The samples were divided into 5 groups of 2...

The aim of this study was to qualitatively demonstrate surface micro-morphological changes after the employment of different surface conditioning methods on high-alumina and glassy-matrix dental ceramics. Three disc-shaped high-alumina specimens (In-Ceram Alumina, INC) and 4 glassy-matrix ceramic specimens (Vitadur Alpha, V) (diameter: 5 mm and height: 5 mm) were manufactured. INC specimens wer...

The dephasing dynamics of a vibrational coherence may reveal the interactions of chemical functional groups with their environment. To investigate this process at a surface, we employ free induction decay sum frequency generation (FID-SFG) to measure the time that it takes for free OH stretch oscillators at the charged (pH ≈ 13, KOH) interface of alumina/water (Al2O3/H2O) to lose their collecti...

Alumina-reinforced carbon nanofiber nanocomposites were prepared using different routes; powders mixture, colloidal route and sol-gel process followed by spark plasma sintering (SPS). CNFs/xAl2O3 (x=10-50 vol.%) were prepared through nanopowders mixing in a high-energy attrition milling. The main limitations in the preparation of this kind of nanocomposites are related to the difficulty in obta...

the effect of γ-al2o3 nanoparticles on heat transfer rate, baffle spacing and pressure drop in the shell side of small shell and tube heat exchangers was investigated numerically under turbulent regime. γ-al2o3-water nanofluids and pure water were used in the shell side and the tube side of heat exchangers, respectively. since the properties of γ-al2o3-water nanofluids were variable, they were ...

the knoevenagel condensation of aromatic aldehydes with barbituric acid, dimedone and malononitrile occurred in the presence of bf3/nano-γ-al2o3 at room temperature in ethanol. this catalyst is characterized by powder x-ray diffraction (xrd), fourier transform infrared spectroscopy (ft-ir), thermal gravimetric analysis (tga), field emission scanning electron microscopy (fesem) and energy-disper...

The entrance of Cd (II) to aqueous environments causes a major problem to human health. The current article examines the efficiency of TiO2 and γ-Al2O3 nanoparticles in Cd (II) removal from aqueous medium as influenced by different chemical factors, such as pH, initial concentration, background electrolyte, and ionic strength, in accordance with standard experimental methods. It conducts Batch ...

Copper oxide supported on γ-alumina nanoparticles were prepared and were well characterized. In this study catalytic activities of the supported copper oxide for oxidation of cyclohexene to 2-cyclohexene-1-ol, 2-cyclohexene-1-one and cyclohexene oxide with TBHP and H2O2 as the oxidant, in the liquid phase were considered. For the CuO/γalumina nanocomposites, acetonitrile as the solvent was empl...

An efficient and green protocol for the synthesis of αaminonitriles derivatives by one-pot reaction of different aldehydes with amines and trimethylsilyl cyanides has been developed using natural alumina, alumina sulfuric acid (ASA), nano-γ-alumina, nanoalumina sulfuric acid (nano-ASA) under microwave irradiation and solvent-free conditions. The advantages of methods are short reaction times, h...