Hydrogen production from water by reduced tin oxide

The production of hydrogen from water by reduced tin oxide has been examined under various experimental conditions. It has been concluded that the reactive species decomposing water is metallic tin. The coexistence of SnO₂ with metallic tin enhances the rate of hydrogen production remarkably. The effect of SnO₂ has been ascribed to the enlargement of surface area of tin metal by its dispersion on the surface of SnO₂. Solid additives such as Pd, Pt, WO₃, CuO and CaO showed a large promoting effect for hydrogen production. The effect of the additives may be explained by increase in the surface area of tin metal or by the spill-over of the activated water by additives onto the surface of SnO₂ or tin metal.     

Contact force detection on a minute aperture mounted optical contact slider using an acoustic emission sensor

Advances in the digital network society require both higher density and higher transfer rates in all sorts of storage systems. Especially in optical recording, the trend toward higher density and larger capacity requires novel surface-recording technologies that can drastically diminish head-to-medium spacing, resulting in an improvement in spatial resolution and, finally, a higher recording density. To this end, we have already proposed a novel contact optical head slider that is able to almost cancel the suspension load by generating hydrodynamic pressure, thus realizing a lower net contact force. Evaluating the dynamic contact force is requisite in realizing its stable sliding operation and higher signal readout performance. In this study, a continuous acoustic emission (AE) signal was utilized to detect the dynamic contact force. AE signal modulation was compared with the applied out-of-plane acceleration on a medium generated by a spindle combined piezo-electric actuator. It was clarified that the detected AE modulation amplitude was approximately proportional to the applied acceleration, and that utilizing AE modulation will be a useful method for evaluating dynamic contact force.     

Thermal properties of ionomer

A series of resol-type phenol-formaldehyde resins with varying phenol/formaldehyde (P/F) molar ratio were investigated by infrared spectroscopy. The infrared spectroscopic data suggest that absorbance ratio of D₂₉₂₀, D₁₆₁₀, D₁₁₅₀, D₁₀₁₀, and D₇₆₀ based on 1 590 cm^?1 band can be used for the determination of phenol/formaldehyde molar ratio of the resins.     

Graphical editing and analysis system for network system (Geans)

Network analysis is powerful in building formal network models of various computational systems or social systems and obtaining their functions and performance exactly because of simplicity of binary relations in networks. Traditionally, it takes lots of effort in network analysis because network analysis was performed by the use of lots of numerical data in batch processing form. Effective network analysis activity, satisfying the system requirements based on consideration for such traditional manner with high cost, requires semiautomatic or computer aided man-machine facilities with interactive editing, analysis, and result viewing functions. We have developed Graphical Editing and Analysis system for Network System (Geans) on DEC PDP-11/34 minicomputer with a graphic display which enables us to edit or modify various network representations and analyze their qualitative and quantitative property, smoothly and interactively with the use of graphics and data abstraction. Geans is composed of a network editing system with effective use of a graphic display, a network data management system with systematic use of network data abstraction, a network analysis system with construction of shared library routines and specific object problem oriented routines, and a node/arc shape definition system. Geans has been applied to various network models such as a transportation analysis problem, PERT/CPM planning, Petri Net analysis and a guidance system for an urban railway network, and moreover it is being applied to other analysis areas as evolving itself.     

Improvement in the remaining activity of freeze-dried xanthine oxidase with the addition of a disaccharide–polymer mixture

In order to improve the remaining activity of a practically important freeze-dried enzyme, xanthine oxidase (XOD), the effects of disaccharide (sucrose and trehalose), polymer (bovine serum albumin: BSA and dextran) and a mixture of them on the loss of XOD activity during freeze-drying and subsequent storage were investigated. All samples were amorphous solids and their glass transition temperatures (T_g) were evaluated by using differential scanning calorimetry. Although dextran showed no stabilizing effect on the freeze-dried XOD, the others protected XOD from the activity loss during freeze-drying to a certain extent. It was found that the mixture of disaccharide (sucrose or trehalose) and BSA improved the XOD activity synergistically. The XOD activity of the samples decreased gradually during storage at a temperature range of between 25 and 60 °C. Samples stored at temperatures below the T_g showed a lower loss of XOD activity than those stored at just the T_g.     

Oligomer Deposition on the Surface of PET Fiber in Supercritical Carbon Dioxide Fluid

Summary: Spin‐drawing yarn (SDY) and high‐speed spun (HSS) fibers were produced from recycled poly(ethylene terephthalate) pellets, and the oligomer deposition on the surface of fiber in supercritical carbon dioxide fluid was compared. The oligomer deposition was obvious for SDY, which corresponded to the fact that the amount of imperfect small crystallites generated in amorphous regions through s‐CO₂ treatment was much smaller for SDY as compared to that with HSS. The imperfect small crystallites generated in amorphous regions will work as a barrier to the oligomer migration. In order to suppress the deposition of oligomer for SDY, the combination of a heatset treatment and an alkaline etching was useful. At a heatset process, the oligomer migration to the surface layer tends to occur, and the layer becomes rich in oligomer. The following topochemical hydrolysis reaction at alkaline etching removes such layer. Accordingly, the total content of oligomer in etched fiber is reduced. As a result, the oligomer deposition in s‐CO₂ treatment becomes not so serious. In addition, the heatset treatment gives the shrinkproof property to SDY, and the property is still retained after the alkaline etching.

     

Development of in-process visualization system for laser-assisted three-dimensional microfabrication using photocatalyst nanoparticles

Recently, microfabrication technology has been used to develop micro-electro-mechanical systems (MEMSs), micro-total analysis systems (μ-TASs), and photonic crystals. Various microfabrication techniques have been proposed; however, a technique that can be used to efficiently fabricate 3-D structures via a simple procedure has not been reported thus far. Because 3-D metal structures have not only mechanical functions but also electromagnetic functions, it is desirable to develop such a technique. Our research group is in the process of developing a new technique for 3-D microfabrication that involves the use of a lower power continuous wave laser. Our technique is characterized by the reduction of silver ions via the photocatalysis of titanium dioxide (TiO2) excited at the laser beam waist. For the analysis and development of our microfabrication technique, we developed a microscope system that enabled us to observe the microfabrication process along the fabrication beam optical axis and its radial direction. We successfully visualized the microfabrication process in 3-D. The visualization showed that when the beam waist was swept, the silver structure grew in 3-D following its path. The effect of the substrate on the deposition condition was examined.     

Contrasting diurnal variations in fossil and nonfossil secondary organic aerosol in urban outflow, Japan

Diurnal variations of fossil secondary organic carbon (SOC) and nonfossil SOC were determined for the first time using a combination of several carbonaceous aerosol measurement techniques, including radiocarbon (1?C) determinations by accelerator mass spectrometry, and a receptor model (chemical mass balance, CMB) at a site downwind of Tokyo during the summer of 2007. Fossil SOC showed distinct diurnal variation with a maximum during daytime, whereas diurnal variation of nonfossil SOC was relatively small. This behavior was reproduced by a chemical transport model (CTM). However, the CTM underestimated the concentration of anthropogenic secondary organic aerosol (ASOA) by a factor of 4-7, suggesting that ASOA enhancement during daytime is not explained by production from volatile organic compounds that are traditionally considered major ASOA precursors. This result suggests that unidentified semivolatile organic compounds or multiphase chemistry may contribute largely to ASOA production. As our knowledge of production pathways of secondary organic aerosol (SOA) is still limited, diurnal variations of fossil and nonfossil SOC in our estimate give an important experimental constraint for future development of SOA models.     

Potato and soy peptides alter caecal fermentation and reduce serum non‐HDL cholesterol in rats fed cholesterol

We examined the effect of potato peptides (PPC) in rats fed a cholesterol‐enriched diet, in comparison with two cholesterol‐enriched diets containing soy peptides (SPC) or casein (CNC), and a cholesterol‐free diet containing casein (CN) for 4 weeks. The serum non‐high‐density lipoprotein (HDL) cholesterol level was lower in the PPC‐ (–18.39%) and SPC‐fed (–32.76%) groups (p <0.05) than in the CNC‐fed group at the end of the feeding period. The low‐density lipoprotein receptor mRNA level in the PPC‐fed group, and cholesterol 7α‐hydroxylase and scavenger receptor class B type 1 mRNA levels in the SPC‐fed group, were higher (p <0.05) than in the CN‐ and CNC‐fed groups. Faecal neutral sterol and caecal short‐chain fatty acid concentrations in the PPC‐ and SPC‐fed groups were higher (p <0.05) than in the CN‐ and CNC‐fed groups. The faecal total acidic sterol concentration was higher in the SPC‐fed group than in the CN‐ and PPC‐fed groups. Caecal anaerobe and Bifidobacterium populations were higher (p <0.05) in the PPC‐ and SPC‐fed groups than in the CN‐fed group. This study suggests that potato peptides, as soy peptides, alter caecal fermentation and steroid absorption and reduce the serum non‐HDL cholesterol level in rats fed cholesterol.     

Preparation and photocatalytic activity of Keggin-ion tungstate and TiO2 hybrid layer-by-layer film composites

Keggin ions (PW₁₂O₄₀³⁻ (PW₁₂), SiW₁₂O₄₀⁴⁻ (SiW₁₂), H₂W₁₂O₄₀⁶⁻ (H₂W₁₂)) and TiO₂ hybrid thin films were prepared using the layer-by-layer method. Their photocatalytic activities were investigated using gaseous 2-propanol decomposition. All films were transparent in the visible wavelength range. For 2-propanol decomposition, H₂W₁₂ was the most effective for the combination with TiO₂ despite having the smallest TiO₂ deposition amount. The photocatalytic activity of the PW₁₂–TiO₂ hybrid film was increased 2.3 times by visible light with UV illumination. This increase was less remarkable for hybrid films of other Keggin ions, suggesting that the visible light excitation of reduced PW₁₂ plays an important role in the enhancement of 2-propanol decomposition.