In the present study, the structural and dynamical properties of water at hydroxylated silica surfaces are investigated with classical molecular dynamics simulations. Depending on the nature of the interface, water molecules are observed to have well defined ordering and slower dynamics compared to bulk water. These properties include the orientation of water near the surface, reorientational r...

objective: the purpose of the study was to evaluate the influence of adding nanofiller particles to a dentin bonding agent on resin-dentin bond strength. materials and methods: fifty-four human intact premolar teeth were divided in to 6 groups of nine. the teeth were ground on occlusal surfaces and polished with 320 and then 600 grit silicon carbide papers. an experimental bonding system based ...

In the initial papers reporting the thermal instability of chemically bonded stationary phases on irradiation with a high-power neodymium laser, Raman scattering intensity in the region 2285 to 1130 cm was found to depend on the density of coverage of the silica matrix with alkyl ligands. Further research focused on the dependence of the growth of UV absorption in this region, on heating of the...

We propose an optomechanical system to quantify the net force on a strand of cleaved silica optical fiber in situ as laser light is being guided through it. Four strands were bonded both sides macroscopic oscillator, whose movements accurately monitored by Michelson interferometer. The was propagating with variable powers and frequency modulations. Experimentally, we discovered that driving for...

objective: this in vitro study evaluated the fracture strength and bending amount of twotypes of fiber reinforced composite (frc) and cast metal frameworks used for fabrication of inlay fixed partial dentures (ifpds). materials and methods: seventy-two extracted first maxillary premolars and molars (36 each) were embedded in acrylic resin to represent a missing of second maxillary premolar. frc...

Uncontrolled population growth and increased consumption of fossil fuels have led to the emission of pollutants and greenhouse gases. This is mostly a concern for reducing emissions of greenhouse gases, such as carbon dioxide because of its impact on global climate change1,2. The presence of carbon dioxide in the natural gas mixture can lead to lower heating value of gas, corrosion of processin...

We present an ab initio investigation of water adsorption on ordered hydroxylated silica surfaces, using the density functional theory within the ultrasoft pseudopotentials and generalized-gradient approximation. The s100d and s111d surfaces of the hydroxylated cristobalite are used as substrates to adsorb water clusters and overlayers. Water adsorbs through hydrogen bonds formed between water ...

The hydroboration of aldehydes and ketones using a silica-supported zirconium catalyst is reported. Reaction of Zr(NMe2)4 and mesoporous silica nanoparticles (MSN) provides the catalytic material Zr(NMe2)n@MSN. Exhaustive characterization of Zr(NMe2)n@MSN with solid-state (SS)NMR and infrared spectroscopy, as well as through reactivity studies, suggests its surface structure is primarily ≡SiOZr...