The importance of Fe loading on the N2O reduction with NH3 over Fe-MFI: Effect of acid site formation on Fe species

Effect of the loading amount of Fe over ion-exchanged Fe-MFI catalysts on the catalytic performance of N₂O reduction with NH₃ was investigated, and the results indicated that the turnover frequency (TOF) was almost constant in the Fe/Al range between 0.05 and 0.40. The activity of N₂O + NH₃ reaction was much lower than that of N₂O + CH₄ reaction over Fe-MFI (Fe/Al = 0.40), and the preadsorption of NH₃ decreased drastically the activity of N₂O + CH₄ reaction. The temperature-programmed desorption (TPD) of NH₃ showed the formation of stronger acid sites on Fe-MFI (Fe/Al = 0.24 and 0.40), and the amount of the acid sites agrees well with the desorption amount O₂ in O₂-TPD in the low temperature range. The acid sites gave a 3610 cm⁻¹ peak (Brønsted acid) in FTIR observation. These results suggest that the acid sites were formed on the bridge oxide ions in binuclear Fe species. Adsorbed NH₃ on the strong acid sites inhibited N₂O dissociation, which can be related to the low activity of N₂O + NH₃ reaction over Fe-MFI with high Fe loading.     

Effect of fermented papaya preparation on dermal and intestinal mucosal immunity and allergic inflammations

BACKGROUND: Fermented papaya preparation (FPP) from yeast fermentation of Carica papaya Linn is a natural health food that is commercially sold in Japan. A previous study revealed that FPP has antioxidant activity. However, the effect of FPP on allergic diseases remains unclear. The aim of the present work was to examine whether the oral administration of FPP to mice restrained two types of contact hypersensitivity models, FITC (Th2 type) induced ear and colon oedema, and oxazolone (Th1 type) induced ear and colon oedema. RESULTS: The sensitisation of FITC or oxazolone increased the plasma levels of IL‐10, IFN‐γ, and TNF‐α. Histological examinations revealed a marked increase of IgA, dendritic cells and inflammatory cells in the colon. When the animals were given FPP before sensitisation by FITC or oxazolone, all the events induced by either FITC or oxazolone decreased markedly. CONCLUSION: These results suggest that the oral administration of the FPP may have a therapeutic potential for the prevention of contact hypersensitive immuno‐response. Copyright © 2008 Society of Chemical Industry     

Silicon microoptical mirrors to make close parallel beams with conventional laser diodes

We have fabricated two kinds of silicon microoptical mirrors to make optical axes of two high-power laser diodes close at an interval of 100 /spl mu/m, utilizing anisotropic etching of silicon with the self-alignment mask. One of them is a microrectangular prism mirror (MRPM). It has two orthogonal reflection mirrors, composed of polished [110] and anisotropically etched (111) planes of silicon. The other is a micro two-reflection mirror (MTRM). It has two pairs of two reflectors facing each other in parallel. The use of MTRM made the mounting process easier than that of MRPM. The use of the self-alignment mask made mirror surface smoother and it has been confirmed that full widths at half maximum (FWHM) are almost the same with and without reflections by MRPM or MTRM, respectively. It has also been shown that the etched (111) plane has the etching-condition dependence of surface roughness.     

Modeling of the I–V curves of the PV modules using linear interpolation/extrapolation

Translation of the I–V curves of solar cells and modules for irradiance G and device temperature T is investigated. A new translation procedure based on the linear interpolation/extrapolation is proposed, in order to translate the I–V curves to target conditions of G and T. The accuracy of the method is investigated based on the indoor and outdoor experimental I–V curves of various kinds of photovoltaic (PV) cells and modules. The calculated the I–V curves over a wide range of G and T well agree with experimental results for various kinds of PV cells and modules. These results indicate that the translation of the I–V curve based on the method is effective for estimating the performance of the PV devices under various climatic conditions.     

Removal properties of low-thermal-expansion materials with rotating-sphere elastic emission machining

Optical mirrors used in extreme ultraviolet lithography systems require a figure accuracy and a roughness of about 0.1 nm rms. In addition, mirror substrates must be low-thermal-expansion materials. Thus, in this study, we processed two low-thermal-expansion materials, ULE [K. Hrdina, B. Hanson, P. Fenn, R. Sabia, Proc. SPIE 4688 (2002) 454.] (Corning Inc.) and Zerodur [I. Mitra, M.J. Davis, J. Alkemper, Rolf Müller, H. Kohlmann, L. Aschke, E. Mörsen, S. Ritter, H. Hack, W. Pannhorst, Proc. SPIE 4688 (2002) 462.] (SCHOTT AG), with elastic emission machining (EEM) in order to evaluate the removal properties. Consequently, we successfully calculated the respective removal rates, because removal volumes were found to be proportional to process times in EEM. Moreover, we demonstrated that the surface roughness of Zerodur is reduced to 0.1 nm rms in the spatial wavelength range from 100 μm to 1 mm.     

Surface layer of Pt-O-Ce bonds on CeOx nanowire with high ORR activity converted by proton beam irradiation

To develop the state-of-the-art polymer membrane fuel cells. Both maximization of oxygen reduction reaction (ORR) activity on Pt cathode and minimization of Pt content in the cathode are required. For this challenge, the defect interface on oxide support was modified by proton beam irradiation method. Pt-CeO_x nanowire/C (Pt/C = 0.02) was fabricated using the proton beam irradiation method. Since the radical density generated by proton beam irradiation is two orders of magnitude greater than that of electron beam irradiation, the CeO_x nanowire surface was fully converted to a thin layer of Pt-O-Ce bonds under proton beam irradiation. The ORR activity observed for fabricated sample with above active surface layer was higher than that of conventional Pt/C (Pt/C = 0.2) and comparable to that of Pt-CeO_x nanowire/C (Pt/C = 0.2) fabricated by conventional methods. From the combination of microanalysis characterization and surface atomistic simulation, we concluded that the Pt-O-Ce bond was formed on defect-rich regions of the CeO_x nanowire and this leads to a maximized ORR activity on the fabricated sample. Based on all experimental data, it is concluded that the surface modification of CeO_x nanowire support using proton beam irradiation is useful for a lowering the Pt content of the cathode with high ORR activity.     

Exploring the possibility of assessing the damage degree of liquefaction based only on seismic records by artificial neural networks

This study presents a new approach to determine the damage degree of liquefaction caused by a large earthquake. We propose an artificial neural network (ANN) model based only on the seismic records of ground and define the degree of liquefaction “DDL” as a damage index. This ANN model predicts the degree of excess pore water pressure increase as the correct output label based on the seismic records obtained from the three-dimensional shaking table test. The proposed model achieved high accuracy, and the outcomes from training data indicated that the ANN model is suitable to function as a liquefaction assessment system. Further, to evaluate the applicability of the proposed ANN model in the real world, the datasets of waves from three actual seismic records were input to the ANN as validation data. The DDL judgment obtained was a good fit with the real phenomena observed.     

On three concepts in robust design optimization: absolute robustness,relative robustness,and less variance

Structural and Multidisciplinary Optimization - This paper provides a clear perspective on existing several different approaches to robust design optimization of structures. We primarily consider...