Nitrogen-doped TiO2 nanotube array films with enhanced photocatalytic activity under various light sources

Highly ordered nitrogen-doped titanium dioxide (N-doped TiO(2)) nanotube array films with enhanced photocatalytic activity were fabricated by electrochemical anodization, followed by a wet immersion and annealing post-treatment. The morphology, structure and composition of the N-doped TiO(2) nanotube array films were investigated by FESEM, XPS, UV-vis and XRD. The effect of annealing temperature on the morphology, structures, photoelectrochemical property and photo-absorption of the N-doped TiO(2) nanotube array films was investigated. Liquid chromatography and mass spectrometry were applied to the analysis of the intermediates coming from the photocatalytic degradation of MO. The experimental results showed that there were four primary intermediates existing in the photocatalytic reaction. Compared with the pure TiO(2) nanotube array film, the N-doped TiO(2) nanotubes exhibited higher photocatalytic activity in degradating methyl orange into non-toxic inorganic products under both UV and simulated sunlight irradiation.     

Electronics and chemistry: varying single-molecule junction conductance using chemical substituents

We measure the low bias conductance of a series of substituted benzene diamine molecules while breaking a gold point contact in a solution of the molecules. Transport through these substituted benzenes is by means of nonresonant tunneling or superexchange, with the molecular junction conductance depending on the alignment of the metal Fermi level to the closest molecular level. Electron-donating substituents, which drive the occupied molecular orbitals up, increase the junction conductance, while electron-withdrawing substituents have the opposite effect. Thus for the measured series, conductance varies inversely with the calculated ionization potential of the molecules. These results reveal that the occupied states are closest to the gold Fermi energy, indicating that the tunneling transport through these molecules is analogous to hole tunneling through an insulating film.     

Stabilization of thermal degradation of poly(methyl methacrylate) by polysulfide polymers

The thermal degradation of poly(methyl methacrylate) (PMMA) in the presence of polysulfide polymers, namely, poly(styrene disulfide) (PSD) and poly(styrene tetrasulfide) (PST) was studied using thermogravimetry (TG) and direct pyrolysis-mass spectrometric (DP-MS) analysis. Both PSD and PST were found to stabilize the PMMA degradation, which was explained by both radical recombination and a chain-transfer mechanism. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 2149–2156, 1997     

Mechanical properties of carbon nanotube–alumina nanocomposites synthesized by chemical vapor deposition and spark plasma sintering

Carbon nanotubes–alumina (CNT–Al₂O₃) nanocomposites with variable CNT content were directly synthesized by chemical vapor deposition (CVD). The as-grown CNT–Al₂O₃ mixture was densified by spark plasma sintering (SPS) at 1150 and 1450 °C. Vickers hardness of 9.98 GPa and fracture toughness of 4.7 MPam^1/2 were obtained for 7.39 wt.% CNT–Al₂O₃ nanocomposite. The addition of CNTs gives rise to 8.4% increase in hardness and 21.1% increase in toughness over that of the pure Al₂O₃. The optimum amount of CNTs is considered to be able to significantly enhance the mechanical property of ceramics in composites.     

Thermal properties of PMMA/montmorillonite clay nanocomposites

Polymer/Clay offer tremendous improvement in wide range of physical and engineering properties for polymers with low filler loading. In nanotechnology polymer/clay nanocomposites use smectitetype clays that have layered structures. In this work, Poly (methyl methacrylate) (PMMA) was synthesized by free radical addition polymerization in the presence of high power ultrasound. The Poly (methyl methacrylate) (PMMA)-Montmorillonite (MMT) clay nanocomposites were synthesized by two different techniques viz., ultrasonic mixing and magnetic stirring. An analysis of the XRD data confirms that the composites are in the nanometer scale. The FTIR spectra show that there is strong interaction between the clay and the polymer that enhances the thermal stability. The thermal stability of the experimental nanocomposite prepared by the two processes is compared. Further analysis of XRD data shows that intercalation as well as exfoliation has taken place in both the types of nanocomposites preparation. An analysis of the TG, DTG curves reveal that the thermal stability is found to increase by nearly 30% for ultrasonic mixing than that of magnetic stirring.     

Microstructural changes in alloy 625 due to creep and characterization using NDE techniques

Alloy 625 exposed to 60,000 hours of service was re- solution annealed at 1433 K and thermally aged at various temperatures in the range of 923–1123 K to produce different microstructures. The microstructures were characterised using scanning electron microscope. Tensile properties and hardness were determined using nondestructive ball indentation technique. Precise ultrasonic velocity measurements were carried out to evaluate the microstructures. A direct correlation has been observed between ultrasonic velocity and mechanical properties. This study demonstrates the feasibility of applying ultrasonic velocity measurements on-line for nondestructive evaluation of mechanical properties of alloy 625.     

Enhanced hybrid CBIR based on multichannel LBP oriented color descriptor and HSV color statistical feature

Multimedia Tools and Applications - Internet applications stores vast quantity of images into databases of server and also several quantities of images are also retrieved from databases. This...     

Assessment of severity in neuropsychiatric disorders based on radiomic features with prior shape level set and metaheuristic algorithms

The diagnostic and clinical overlap between schizophrenia (SZ) and schizoaffective (SA) is vital oncological issue in psychiatry disorder. This study is designed to examine tissue variation in cerebellum region. Shape prior levelset method is used to segment cerebellum from MR image, and is subdivided by symmetry line detection. Radiomic features are extracted and subjected to Binary PSO (BPSO) fuzzy-SVM classifier. This work is evaluated on COBRE database. The results show that, shape prior levelset could segment cerebellum region with better similarity values. The Laplacian of Gaussian and structure tensor features extracted from right cerebellum gives high significance between SA and SZ (P < 0.00001). The BPSO-FSVM could classify the normal, SA, and SZ with an accuracy of 88.33%. The AUC is 0.913 for the combined features extracted from right cerebellum. It is concluded that optimized feature selection-based classifier gives better results. This study is clinically helpful in the investigation of psychiatry disorder.     

Security Scheme in Cloud System Using Hyper Elliptic Curve and SIFT Technique with QR Code

Wireless Personal Communications - When concerned about cloud the security has to be the major factor considered by providers of service. Double encryption is a tool used by the storage server to...