Advanced Materials Research Vols. 622-623

Abstract: PET/Clay nanocomposites were prepared by the melt blending of PET and 3% wt. closite20A nanoparticles. The stretch blow molding machine was used to produce bottles from neat PET and PET nanocomposite. Migration of silicon from PET nanocomposite bottles into acidic food simulnat was studied at two storage temperatures (25°C and 45°C) in different time intervals from 7 to 70 days. A specific surface of sheets (prepared from PET/clay nanocomposite) immersed in acidic food simulnat and two-sided migration of silicon investigated. Using XRD analysis and TEM micrographs displayed both intercalation and exfoliation morphology for PET/clay nanocomposites. Inductive coupled plasma (ICP) used to quantify the amount of Silicon migrated into acidic food simulnat. It was observed that the migration process is depended on the storage time and temperature as well as the morphology of nanocomposites.

Abstract: The use of nanoparticles has spannded many divisions of biological fields including sensors, drug delivery and clinical diagnosis. These functions all based on the most important action in cells called Endocytosis. The study of endocytosis in higher order plants remained inactive for a long period of time. In this work we use Silver Nano Particles (S.N.Ps) as a endocytosic substances were incubated by isolated protoplast of petunia .Concurrently, with the study of internalization, their appear aggregation inter and intracellular were investigated by Transmissions Electron Microscopy (TEM). Results and observations showed that the S.N.Ps crossed the cell membrane and internalized in to the cells. It can be assumed that the particles with the organic functionality – PEG coated – were internalized by the petunia protoplasts.

Abstract: Nitrogen-loaded TiO₂ (N-loaded TiO₂), a visible-light driven catalyst, was successfully synthesized by the modified sol-gel method. Physical characterizations of the as-prepared catalysts have been performed by using X-ray diffraction (XRD), Diffuse reflectance UVvisspectroscopy(DRUVvis), Raman spectroscopyand BETspecific surface areain order to obtain structure-activity relationship. Results from Raman spectroscopy clearly suggested that N atoms were incorporated into the TiO₂ crystal lattice as evidenced by the vibrational peak of TiN in TiO_2-xN_x.DR UVvis results also suggested that the nitrogen dopant might be responsible for narrowing the TiO₂band gap energy, thus resulting in a shift towards the visiblelight region. Photocatalytic activity of N-loaded TiO₂ evaluated through the degradation of methyl orange (MO)under visible light irradiation (l> 400 nm) indicated that all N-loaded photocatalysts exhibited significantly higher activities than the unloaded TiO₂ and Degussa P25 TiO₂. According to the results from DR UV-vis, XRD and BET studies, the enhanced photoactivity observed from N-loaded samples might be due to a decrease in TiO₂ band gap energy and/or changes in chemical and physical properties of the materials upon loading with nitrogen.

Abstract: In this report, we propose a direct silica-coating technique to enhance the stability of silver nanoparticles as a doping additive to enhance the thermal conductivity phase change materials (PCM). Our experimental results show that a thin layer of silica can protect silver nanoparticles and help retain its intrinsic metallic properties, when subjected to harsh corrosive environments found in PCM media. Furthermore, PCM materials can be effectively used to cool the ambient temperature of a building room by up to ~1.2 degree Celsius. Our preliminary results demonstrate a real opportunity in air-conditioning energy-savings for buildings using enhanced PCM.

Abstract: The bioceramics, calcium hydroxyapatite (HA), is a material which is biocompatible to the human body and is well suited to be used in hyperthermia applications for the treatment of bone cancer. We synthesis hydroxyapatite in modified synthetic body fluid (SBF) solutions at 37°C and pH of 7.4 using a novel chemical precipitation technique. Then after heat operation, on filtered precipitated result HA were produced. For loading the silver nanoparticles (Ag NPs) on the hydroxyapatite we use AgNO3 solution. And for reducing Ag+ ions apply sodium borohydrate solution. The formations of the silver nanoparticles on the HAP structure were confirmed by X-ray diffraction, transmission electron microscopy (TEM). TEM image show the nanostructure of silver particles, being formed on hydroxyapatite texture.

Abstract: Polymer-ceramic nanocomposites with controlled dielectric properties are prepared using poly(dimethylsiloxane) elastomer as base matrix and barium titanate as filler. Barium titanate (BaTiO3) used in this study is prepared by solid state reaction at high temperature. The effect of BaTiO3 nanoparticles on electrical and mechanical properties are extensively studied and found that dielectric constant of nanocomposites increases significantly with the increase in BaTiO3 concentration where as volume resistivity decreases continuously. Different mechanical properties are also studied for all the composites in order to find the effect of filler concentration. Morphology of the prepared BaTiO3 was studied by field emission scanning electron microscope (FESEM).

Abstract: Diamond-like carbon (DLC films were deposited on NiFe coupon by Filtered Cathodic Arc (FCA) technique. Two different DLC thicknesses were selected to compare thickness dependency on film properties change. The mechanical property as wear resistance under cyclic heating condition was investigated by nanoindenter (Hysitron). The detail of DLC film composition change was also studied using X-ray Photoelectron Spectroscopy (XPS). The roles of heating in material composition and wear behavior of DLC films are discussed. The effect of DLC film thickness is also considered. The results showed that thinner DLC (2 nm) has higher carbon oxidation resulting that deteriorate in wear resistance as compare to thicker one (5 nm). The heating accelerates these oxidation and wear in this study. .

Abstract: The water molecule, H2O is a very simple and most stable molecule. It displays a discrete but nevertheless exceptional property that has far-reaching consequences, one of them being that without it life would not exist. At ambient conditions, water remains in liquid form, becomes ice below freezing temperatures and turns into vapor form at high temperatures. In this paper, we use molecular dynamics (MD) simulation method to study the hydrodynamic properties of water molecule. The interactions that exist in the water molecule is described using the 3 site transferable inter-molecular potential model. The properties of water molecule that occur at nano level are studied and compared with those at the bulk.

Abstract: In order to improve fracture toughness, nanocrystalline hydroxyapatite (HA) powder was used for fabricate dense HA nanoceramic. The nanocrystalline HA powder was obtained with ball milling for 12 h from calcined natural bovine bone. The green compacts of HA nanopowder were sintered by pressureless sintering with non-linear heating rate sintering at 1200°C for 3 h. Fracture toughness and hardness properties of HA nanoceramic have been assessed using indentation technique. The fracture toughness values of sintered nanosized-HA powder is 3.50.1 MPa.m^1/2, which is within those of human cortical bone. The nanostructure with liquid phase sintering of sintered nanosized-HA powder contributed to the increase of fracture toughness. The toughening mechanisms of pull-out of nanocrystalline HA and grain boundary sliding have been observed.

Abstract: Porous ceramics filter was prepared by sintering of hydroxyapatite (HA) and silica composite nanopowder. Silica nanopowder of 50 wt% are incorporated into HA nanopowder. The mixing powders are uniaxially compact and then sintering at 900°C-1050°C in air. The characterization of the porous was carried out by scanning electron microscopy (SEM). Filtration studies using porous ceramic were performed for agricultural wastewater. The studies of the water filtration and flow through these porous showed that the sintered ceramic filter at all temperatures reduced the TDS, TS, conductivity, and arsenic (As) content. The water permeated through porous ceramic composites could be compared to drinking water quality.