Preparation of zeolitic adsorbents from waste coal fly ash

Power plants burning coal generate a large amount of fly ash as waste matter. The objective of this study is to produce zeolitic adsorbents that possesses high adsorptive capacity for toxic cations. The sample was first pretreated with a High Intensity Magnetic Separator for the removal of iron and magnetic materials (mainly Fe₂O₃ and TiO₂). The zeolitic adsorbents were prepared under the various conditions of NaOH concentration (1–5 N), reaction time from 3 to 96 hours and at the various temperatures of 60, 80 and 100°C. The results of the experiment showed that the coal fly ash should be synthesized with 4 N NaOH for 48 hours at 100°C in order to have good adsorptive capacity. The zeolitic adsorbents showed higher cation exchange capacity values than the natural zeolite in removing NH ₄ ⁺ , Pb²⁺, Ca²⁺and Cd²⁺ions.     

Reflective color display using thermochromic pigments

A reflective thermochromic display fabricated by a very simple method using three kinds of thermochromic pigments is produced and its thermo-optical characteristics are investigated. The display exhibits maximum red, green, and blue reflectances of 38%, 30%, and 35%, respectively. The reflective display cell shows continuous gray color with changing temperature, which is crucial for multicolor displays. It also shows an excellent viewing angle above 80° without any of the additional optical components that are required in liquid crystal displays. We expect that this display technology will be used for outdoor billboard information display applications.     

Fabrication of high-density In(3)Sb(1)Te(2) phase change nanoarray on glass-fabric reinforced flexible substrate

Mushroom-shaped phase change memory (PCM) consisting of a Cr/In(3)Sb(1)Te(2) (IST)/TiN (bottom electrode) nanoarray was fabricated via block copolymer lithography and single-step dry etching with a gas mixture of Ar/Cl(2). The process was performed on a high performance transparent glass-fabric reinforced composite film (GFR Hybrimer) suitable for use as a novel substrate for flexible devices. The use of GFR Hybrimer with low thermal expansion and flat surfaces enabled successful nanoscale patterning of functional phase change materials on flexible substrates. Block copolymer lithography employing asymmetrical block copolymer blends with hexagonal cylindrical self-assembled morphologies resulted in the creation of hexagonal nanoscale PCM cell arrays with an areal density of approximately 176?Gb/in(2).     

Effectively reinforcing roles of the networked silica prepared using 3,3′-bis(triethoxysilylpropyl)tetrasulfide in the physical properties of SBR compounds

The networked silica having pre-fabricated networks among silica particles is a new concept for the reinforcement of rubber compounds. The networked silica was designed to improve the fuel efficiency of tires while eliminating the disadvantages such as precure and ethanol production that arise in the conventional reinforcing system using coupling reagents. The networked silica was prepared using bis(triethoxysilylpropyl)tetrasulfide (TESPT) as a connecting chemical at various loading levels. The styrene–butadiene rubber (SBR) compounds reinforced with the networked silica exhibited low filler–filler interaction and high rubber–filler interaction due to the entanglements between the rubber molecules and the connecting chains of the networked silica. The increased physical interaction improved the elastic properties and wear resistance, while lowering the rolling resistance of the rubber compounds, resulting in long tire service life and high automobile fuel efficiency. The enhanced physical properties of the SBR compounds reinforced with the networked silica supported their promising potential as reinforcing fillers for tire manufacture. The networked silica can readily replace the conventional silica-reinforced system, without requiring major modification of the processing conditions.     

Effect of isocyanate‐modified fumed silica on the properties of poly(butylene succinate) nanocomposites

Using the grafting method on a silica surface with PBS molecules, we prepared novel poly(butylene succinate) (PBS)/silica nanocomposites to enhance dispersibility and interfacial adhesion between silica particles and the PBS matrix, and also investigated the effects of silica‐g‐PBS on the PBS matrix using differential scanning calorimetry, thermogravimetric analysis, transmission electron microscopy, a tensile testing machine, and rheometry. The thermal stability, mechanical properties, and rheological properties of PBS nanocomposites containing silica‐g‐PBS was remarkably improved because of the surface characteristics of the silica grafted with PBS molecules, which provided good compatibility and dispersion. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effect of buffer layer thickness on the growth properties of hydrothermally grown ZnO nanorods

We investigated the effect of ZnO buffer layer thickness on the growth of hydrothermally grown ZnO nanorods. A series of ZnO buffer layers with different thicknesses was deposited on a p-Si (111) substrate using a co-sputtering system. After annealing the ZnO buffer layer, ZnO nanorods grown were grown hydrothermally at 95 degrees C. Unlike ZnO nanorods grown on as-deposited ZnO buffer layer, the diameter and length of ZnO nanorods grown on annealed ZnO buffer layers can be controlled. The structural and optical properties of ZnO nanorods grown on annealed ZnO buffer layers were analyzed by field-emission scanning electron microscopy, X-ray diffraction, and photoluminescence. The influence of ZnO buffer layer thickness on ZnO nanorods growth is discussed.     

Synthesis and characterization of 3-[131I]iodo-L-tyrosine grafted Fe3O4@SiO2 nanocomposite for single photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI)

In this study, we have successfully developed 3-[131I]iodo-tyrosine grafted Fe3O4@SiO2 nanocomposites for dual potential tumor imaging agent for SPECT and MRI. Fe3O4 nanoparticle was synthesized through thermal decomposition and Fe3O4@SiO2 was prepared by reverse microemulsion method. After conjugating aminopropyltriethoxysiliane, L-tyrosine was introduced by amide coupling reaction. Finally, [131I]iodide was labeled on L-tyrosine grafted Fe3O4@SiO2 nanocomposite by aromatic iodination using chloramine-T.     

Morphologies of nano-sized apatite formed on titanium substrate by biomimetic process

The apatite was formed on the titanium plates with NaOH and heat treatments by biomimetic process. The influence of titanium surface microstructure on the apatite formation onto titanium substrate in SBF solution was investigated. After biomimetic process, nano-sized apatite layers were found on the Ti plates with NaOH and heat treatments. However, the morphologies of formed apatite on substrate had different shapes such as coated, load-like, and linked. The morphology of apatite formed by biomimetic process would be affected by alkaline treatment, and substrate morphology and phase.     

Experimental study of honeycomb regenerator system for oxy-fuel combustion

An experimental study of a honeycomb regenerator for oxy-fuel combustion has been performed. A laboratory-scale test rig is set up and various experimental parameters such as cell density and length of the honeycomb regenerator, switching time, and bypass effect are investigated. The typical temperature trend of the heating and regenerating process is obtained for the oxy-fuel combustion. The regenerative characteristics for various combinations of these parameters are shown. It is found that part of the exhaust gas should be bypassed to use waste heat more efficiently and to optimize the efficiency of the honeycomb regenerator system for oxy-fuel combustion.