Search

Application of a finite element method that involves an assumed phase state technique helps solve the one- and two-dimensional heat conduction problems in aircraft. The method also helps analyze the impact of surface curvature on the numerical data and simulate the electrothermal de-icer aircraft surface. Curvature effects are negligible when the surface curvature has a less than 0.25 value.

A mathematical temperature based finite element method (FEM) with assumed states is used to solve aircraft deicing problems. The resulting algorithm and formulation are more efficient than conventional FEM procedures, resulting in the use of less computer time. This enables the algorithm to be used for aircraft deicing problems which relate to phase change.

The nanocomposites of gold nanoparticles and multi-walled carbon nanotubes (MWCNTs) have been applied in the enhanced electrochemical detection of DNA hybridization. Gold nanoparticles coated on MWCNTs uniformly were synthesized by simply one step reaction. Target DNA was detected by the peak current difference of differential pulse voltammetry (DPV) signals of the electroactive indicator methylene blue (MB) before and after hybridization on the Au/MWCNTs modified glass carbon electrode (GCE). Due to the excellent electrical conductivity of the novel matrix, the biosensor revealed high sensitivity with the detection level down to 1.0 pM. Excellently selectivity and reproducibility were also discussed. [ABSTRACT FROM AUTHOR]

Abstract: Stannic oxide sensors were developed to monitor CO of 10–250 ppm concentrations. Cross sensitivities of these sensors against 100–2000 ppm methane can be suppressed by evaluating the features extracted from the sensor signals. For this purpose, the working temperature of the sensors was modulated between 250 and 300  C, and the dynamic responses were measured to different concentrations of CO, CH4, and their mixtures were measured. The discrete wavelet transform (DWT) was used to extract important features from the sensor responses. These features were then input to the pattern recognition (neural) method. The species considered can be discriminated with a 100% success rate by using a back propagation network and the concentrations of the gases studied can also be accurately predicted. [Copyright &y& Elsevier]

(Zr,Sn)TiO4 nano-powders for microwave ceramics were prepared by a hydrothermal synthesis route. Raw materials of ZrOCl2, ZrO(NO3)2, SnCl2, TiO2 and de-ionized water were used, and the mixture was stirred in an auto-clave at 160–230 °C. Resulting powders with particle size of 10–120 nm were washed, dried and pressed into pellets, which were then sintered at 1200–1300 °C. The sintering process was analyzed by TGA and DTA. Microstructures of the powder and sintered ceramics were observed by TEM and SEM. Crystalline phases of the ceramics were identified by XRD. Dielectric properties of the samples were: dielectric constant 30–45 and Q*f=10,000–25,000 GHz at 10 GHz. [Copyright &y& Elsevier]

Ba2Ti9O20 nano-powders for microwave ceramics were prepared by a hydrothermal synthesis route. Raw materials of Ba(OH)2·8H2O (AR), TiO2 (CP)and de-ionized water were used, and the mixture was stirred in an auto-clave at 130–200 °C. Resulted powders with particle size of 10–120 nm were washed, dried and pressed into pellets, which were then sintered at 1200–1300 °C. Sintering process was analyzed by TGA and DTA. Microstructures of the powder and sintered ceramics were observed by TEM and SEM. Crystalline phases of the ceramics were identified by X-ray diffraction. Dielectric properties of the samples were also measured, displaying dielectric constant of 25–55 and Qf=1000–15000 GHz at 10 GHz. [Copyright &y& Elsevier]

Sr(Bi1−xNdx)8Ti7O27 ceramics for wireless technologies were prepared by a solid-state reaction route. Raw materials of SrCO3, Bi2O3, Nd2O3 and TiO2 were used. The mixture was ball-milled, dried, and hydro-pressed into pellets or formed into green body by gel-casting, which were then sintered at 1180–1300 °C. Sintering process was analyzed by TGA and DSC. Microstructure of ceramic body was observed by SEM. Crystalline phases of the ceramics were identified by X-ray diffraction. Dielectric properties of the samples were also measured, showing dielectric constant ϵ=80–110 and Qf=120–2100 GHz at 10 GHz. [Copyright &y& Elsevier]