Prediction of ignition behavior in a tangentially fired pulverized coal boiler using CFD

Prediction of pulverized coal ignition behavior in a 40 MW tangentially fired commercial boiler is studied. Pulverized coal combustion simulation is performed considering radiation properties of particles. Coal devolatilization and char combustion are modeled and the first order spherical harmonic approximation is used to model the radiative transfer equation. To confirm the accuracy of the simulation method, the results are confirmed by available operating data, design data, and the ignition image in the boiler whose inside is observed by the developed high temperature resistant CCD video camera system. The work indicates that the simulation method can be applied to commercial boilers and predict the ignition behavior with considering not only coal properties but also boiler operating conditions.     

Analysis of Human Oral Mucosa Ex Vivo for Fatty Acid Compositions Using Fourier-transform Infrared Spectroscopy

The purpose of this research was to develop an infrared spectroscopic technique (Fourier transform infrared spectroscopy with attenuated total reflectance system; FTIR-ATR) for non-invasive measurement of saturated and unsaturated fatty acid compositions in human oral mucosa obtained from three nationalities; Iranian, Vietnamese, and Indonesian. The histogram patterns of fatty acid compositions for three nationalities suggest that the pattern of unsaturated fatty acids were quite different, although the distribution profiles of fatty acid to lipid ratios in FTIR-ATR has a similar normal pattern with small difference in skewness and mode. The second derivative infrared spectra of the mucosal tissues in the wavenumber regions from 1,600 to 1,760 cm⁻¹ and 2,800 to 3,050 cm⁻¹ were analyzed with partial least squares (PLS) multivariate regression analysis method. With this analysis method we compared predicted values with the measured values of ten categorized fatty acid compositions, i.e., a(saturated C17 or lower), b(C16:1 + C17:1), c(C18:0), d(C18:1), e(C18:2), f(saturated C20 or longer), g(C20:3 + C20:4), h(C22:1 + C24:1), i(C22:6), j(γC18:3). Almost all fatty acid compositions of oral mucosa were well predicted with differences between predicted and measured values within ±5% of total, however, errors were relatively larger in minor components such as C22:6 than major components.     

Development of a catalytic decomposition system for chlorofluorocarbons

It is becoming increasingly important to decompose chlorofluorocarbons (CFC), which destroy the ozone layer. The purpose of this study is to investigate the CFC decomposition activities of a catalyst and a decomposition system. CFC decomposition with H₂O by KI‐100 catalyst, a TiO₂‐based catalyst which we have developed, was investigated. KI‐100 catalyst showed high activity for CFC11, CFC12, and CFC113 decomposition. However, the conversion rate CFC113 decreased with time and was 70% after 1000 h. In order to determine the cause, the KI‐100 catalyst was analyzed. From the results of quantitative analyses, it was found that the weight of TiO₂ in the catalyst decreased from 11.42 g to 1.09 g (–90.5 wt%) and TiO₂ changed to TiOF₂. To prevent the formation of TiOF₂, another component, which was less reactive with CFC than TiO₂, was applied to the catalyst surface. The improved catalyst, KI‐1000, showed long durability for CFC12 decomposition and the conversion rate was above 99.99% over 2000 h. Based on these results, we have commercialized Catalytic Decomposition Equipment for CFCs. © 2000 Scripta Technica, Electr Eng Jpn, 132(1): 57–63, 2000     

Properties and structure of poly(vinyl alcohol)/silica composites

The relationships between the properties and structure are discussed for poly(vinyl alcohol)(PVA)/silica composites prepared through the sol‐gel process. The composites became stiff and brittle with increasing the silica content. The properties of the composites were changed drastically at around the composition of PVA/silica = 70/30 wt %. For example, there was no large change in the Young's modulus above 30 wt % of silica content (Pure PVA: 31.8 MPa, silica 30%: 52.6 MPa, silica 50%: 55.2 MPa). Consequently, it was considered that the three‐dimensional network structure of silica could be formed in the composite with more than 30 wt % of silica in PVA. From this behavior, it could be considered that the crystal growth of PVA was remarkably inhibited by silica network. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 133–138, 1999     

Detection of Immunomodulating Activities in an Extract of Japanese Edible Seaweed,Laminaria japonica (Makonbu)

A significant immunomodulating activity was found in the hot-water-soluble extract of the most popular edible seaweed in Japan, Laminaria japonica (Makonbu in Japanese) which showed an enhancing activity for DNA synthesis of spleen cells from endotoxin-nonresponder, C3H/HeJ mice. This activity was divided into polysaccharide and non-polysaccharide fractions and the former fraction exhibited much higher activity than that of the latter fraction. The polysaccharide fraction caused stimulatory effects on the ingestive activity of mouse phagocytic cells against Staphylococcus aureus and the release of cytokines, interleukin-1α and tumour necrosis factor α from the same cells. Furthermore, the polysaccharide fraction exhibited enhancing effects on polyclonal antibody (IgM and IgG) production in spleen cells. These immunomodulating activities were associated with polysaccharides themselves, but not contaminating endotoxins in the fraction judged by comparative experiments. The significance of this finding is discussed from the viewpoint of the immunopotentiation by edible seaweeds in host animals.     

Polyether-segmented nylon hemodialysis membrane. VI. Effect of polyether segment on morphology and surface structure of membrane

Amorphous nylon, poly(iminoisophthaloyliminomethylene-1,3-cyclohexylenemethylene) (NyBI) and poly(ethylene oxide) (PEO)-segmented NyBI (PEO–NyBI) membranes were prepared by a phase-inversion method using water/dimethyl sulfoxide (DMSO) mixtures as coagulants. The influence of the PEO segment and coagulant compositions on the morphology of the membranes was investigated. The cloud-point curves in the polymer/DMSO/water ternary system showed that PEO–NyBI and NyBI had the same coagulation processes, that is, instantaneous liquid–liquid phase separation occurred, resulting in a fingerlike structure in the cross section of the membranes. The membrane morphologies observed under a scanning electron microscope (SEM) agreed with the prediction. The PEO segment had little or no effect on the membrane morphologies which were prepared in the coagulants with a low DMSO concentration, and it promoted the change of the phase-separation style from the instantaneous to the delayed one in the case of the DMSO-rich coagulant. The PEO segment, however, significantly influenced the ultrafiltration rate. Additionally, the relationship between the surface composition of the PEO–NyBI membrane and the coagulation condition was also investigated by use of electron spectroscopy for chemical analysis (ESCA) and static secondary ion mass spectrometry (SSIMS). A small enrichment of the PEO segment at the top surface of the membranes was observed with the increase of the DMSO concentration in the coagulant. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1645–1659, 1998     

A current sensor using the Faraday effect in optical fiber manufactured from flint glass

For application to current monitoring in electric power facilities, the authors have been developing a current sensor utilizing the Faraday effect of an optical fiber manufactured from flint glass having a very small stress-optic coefficient. This paper describes the result of study on constructing the sensing system, which is composed of a sensor head, a light source, fibers for light transmission and a signal processing circuit. First, results from investigation are reported with respect to causes affecting performance and durability of the sensor, and examinations of countermeasures also are described. As a result of the research, it was confirmed experimentally that several means are effective to improve characteristics of the sensor. Then, design and test results of a sensor model constructed with application of the means are described. From the test results it was proved that the model shows excellent characteristics satisfying basic requirements of the standard for conventional current transformers. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 118 (3): 22–38, 1997     

Polyether-segmented nylon hemodialysis membranes. II. Morphologies and permeability characteristics of polyether-segmented nylon 610 membrane prepared by the phase inversion method

The relationships between the morphologies and the permeability characteristics as dialysis membrane of polyether-segmented nylon 610 (PE-Ny610) have been investigated. PE-Ny610 used are poly(propylene oxide) (PPO)-segmented nylon 610 containing 25 wt % PPO (PPO-Ny610) and poly(ethylene oxide) (PEO)-segmented nylon 610 containing 15 wt % PEO (PEO-Ny610). The morphologies in the cross section of the membranes exhibit the cellular porous structures due to liquid-liquid phase separation. On the other hand, the structures of the surfaces are mainly composed of the crystalline spherulite due to liquid-solid phase separation. These morphologies are little affected by the composition ratio of the coagulant, calcium chloride/methanol/water mixture. PEO-Ny610 membranes have shown superior membrane performances to the PPO-Ny610 membrane. The effect of PEO content in PEO-Ny610 on the adhesion of platelet onto the PEO-Ny610 film surface was investigated and it is concluded that PEO-Ny610 having > 10 wt % PEO shows a good nonthrombogenicity equal to PPO-Ny610. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1713–1721, 1997     

Photocatalytic decomposition of NO under visible light irradiation on the Cr‐ion‐implanted TiO2 thin film photocatalyst

Transparent TiO₂ thin film photocatalysts were prepared on transparent porous Vycor glass (PVG) by the ionized cluster beam (ICB) method. In order to improve the photocatalytic performance of these thin films under visible light irradiation, transition metal ions such as Cr and V were implanted into the deep bulk inside of the films using an advanced metal‐ion‐implantation technique. The UV‐vis absorption spectra of these metal‐ion‐implanted TiO₂ thin films were found to shift smoothly toward visible light regions, its extent depending on the amount and kinds of metal ions implanted. Using these metal‐ion‐implanted TiO₂ thin films as photocatalysts, the photocatalytic decomposition of NO_x into N₂ and O₂ was successfully carried out under visible light (λ 450 nm) irradiation at 275 K. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermodynamics of high swelling of polymer particles with a large amount of monomer utilizing the dynamic swelling method

Recently, we suggested a novel swelling method to make polymer seed particles absorb a large amount of monomer prior to the seeded polymerization for preparing monodispersed polymer particles having diameter above 5μm, which we named the “dynamic swelling method.” This article discusses the thermodynamic background of this method, both theo-retically and experimentally. © 1996 John Wiley & Sons, Inc.