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An analytical solution is presented for the axisymmetric static responses of thick functionally graded (FGM) cylindrical shells with general boundary conditions, which strictly satisfies the boundary conditions along the thickness. The illustrative examples show that the presented solution of thick cylindrical shells under various boundary conditions is of high precision and good convergence. The exact distributions of displacement and stress components along the radial and axial directions are revealed, and the influences of thickness-to-radius ratio, span-to-radius ratio and material gradient index on the static responses of the thick FGM cylindrical shell are analyzed. [ABSTRACT FROM AUTHOR]

A colorimetric sulfur dioxide (SO2) gas sensor based on a core–shell composite was developed. The composite was fabricated with a silicon dioxide core and a mesoporous MCM-41 shell (SiO2@MCM-41), and further loaded with a mixture of zinc chloride (ZnCl2), sodium nitroprusside (SNP) and hexamine as an SO2 indicator. The sensing properties of SiO2@MCM-41 toward SO2 were measured in solid powder, discs and a gas detection tube (GDT), respectively. Each of these sensing configurations showed a distinct color change from pale yellow to red, which indicates good potential for naked-eye detection of SO2. The limit of detection (LOD) is 2 ppm for SiO2@MCM-41 discs, which indicates high sensitivity to SO2. The performance of GDT suggested a linear relationship between the SO2 concentration and the response length of the red portions in a range of 100–1000 ppm. This work shows promising potential of SiO2@MCM-41 as an easy, effective and rapid response sensing material for the in situ detection of SO2. [ABSTRACT FROM AUTHOR]

In this paper, Sr 2 Fe 1.5 Mo 0.4 Nb 0.1 O 6−δ (SFMNb)−xSm 0.2 Ce 0.8 O 2−δ (SDC) (x = 0, 20, 30, 40, 50 wt%) composite cathode materials were synthesized by a one-pot combustion method to improve the electrochemical performance of SFMNb cathode for intermediate temperature solid oxide fuel cells (IT-SOFCs). The fabrication of composite cathodes by adding SDC to SFMNb is conducive to providing extended electrochemical reaction zones for oxygen reduction reactions (ORR). X-ray diffraction (XRD) demonstrates that SFMNb is chemically compatible with SDC electrolytes at temperature up to 1100 °C. Scanning electron microscope (SEM) indicates that the SFMNb-SDC composite cathodes have a porous network nanostructure as well as the single phase SFMNb. The conductivity and thermal expansion coefficient of the composite cathodes decrease with the increased content of SDC, while the electrochemical impedance spectra (EIS) exhibits that SFMNb-40SDC composite cathode has optimal electrochemical performance with low polarization resistance ( R p ) on the La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3 electrolyte. The R p of the SFMNb-40SDC composite cathode is about 0.047 Ω cm 2 at 800 °C in air. A single cell with SFMNb-40SDC cathode also displays favorable discharge performance, whose maximum power density is 1.22 W cm −2 at 800 °C. All results indicate that SFMNb-40SDC composite material is a promising cathode candidate for IT-SOFCs. [ABSTRACT FROM AUTHOR]

A colorimetric sulfur dioxide (SO 2 ) gas sensor based on a core-shell composite was developed. The composite was fabricated with a silicon dioxide core and a mesoporous MCM-41 shell (SiO 2 @MCM-41), and further loaded with a mixture of zinc chloride (ZnCl 2 ), sodium nitroprusside (SNP) and hexamine as an SO 2 indicator. The sensing properties of SiO 2 @MCM-41 toward SO 2 were measured in solid powder, discs and a gas detection tube (GDT), respectively. Each of these sensing configurations showed a distinct color change from pale yellow to red, which indicates good potential for naked-eye detection of SO 2 . The limit of detection (LOD) is 2 ppm for SiO 2 @MCM-41 discs, which indicates high sensitivity to SO 2 . The performance of GDT suggested a linear relationship between the SO 2 concentration and the response length of the red portions in a range of 100-1000 ppm. This work shows promising potential of SiO 2 @MCM-41 as an easy, effective and rapid response sensing material for the in situ detection of SO 2 .