COMPARISON OF PAHS,NITRO-PAHS AND OXY-PAHS ASSOCIATED WITH AIRBORNE PARTICULATE MATTER AT ROADSIDE AND URBAN BACKGROUND SITES IN DOWNTOWN TOKYO,JAPAN

Atmospheric polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs and oxy-PAHs are emitted from primary sources. Some nitro-PAHs and oxy-PAHs can also arise from secondary formation in the atmosphere. To assess the relative importance of these sources, the polycyclic aromatic compound (PAC) concentrations were determined at a roadside (Roadside site) and on a rooftop (Urban Background site) in downtown Tokyo Japan. The concentrations of PAHs, 1-nitropyrene and oxy-PAHs at the Roadside site were higher than those at the Urban Background site, while 2-nitrofluoranthene levels were the same at both sites. However, the mean ratios of concentrations at the Urban Background site to the Roadside site were in the order 1,8-naphthalic anhydride>9,10-anthraquinone>PAHs or 1-nitropyrene or acenaphthenequinone or benzanthrone. This suggests that in addition to vehicle emissions, a considerable fraction of some of the oxy-PAHs studied originates from another source, which might be secondary formation by atmospheric PAH degradation, and this contribution varied among the oxy-PAHs.     

Pore‐size evaluation and gas transport behaviors of microporous membranes: An experimental and theoretical study

A modified gas‐translation (GT) model based on a GT mechanism was successfully applied to the pore‐size evaluation and gas transport behavior analysis of microporous membranes with different pore‐size distributions. Based on the gas permeation results of three microporous membranes derived from different alkoxides, the effects of activation energy and the selection of a standard gas on the pore‐size evaluation were discussed in a comparative study. The presence of nano‐sized defects had an important influence on the gas permeation performance of microporous membranes, depending largely on the original pore size of the membrane in question. Moreover, the gas‐separation effect of the pore‐size distribution in a silica membrane was theoretically studied and revealed a significant increase in gas permeance for relatively large gas species but not for small ones. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2268–2279, 2015     

Gas permeability of thin dense films from polymer blend of thermoplastic elastomer and polyolefin

Stretched thin films composed of a thermoplastic elastomer, a polystyrene‐block‐poly(ethylene butylene)‐block‐polystyrene triblock copolymer (SEBS), and polyolefins, poly(ethylene‐co‐ethylacrylate) and poly(ethylene‐co‐propylene), were obtained by blow‐molding, uniaxial stretching, and cooling to room temperature and the gas permeability of the stretched films was investigated. When the as‐blown annealed film was subjected to uniaxial stretching in the machine direction, P_O2 and P_N2 increased with an increase in the stretching ratio K and approached a constant value at high stretching ratios. In addition, P_O2/P_N2 decreased gradually with K and approached a value of 2.95–3.0. The reason for this unique gas permeation behavior is that the molecular mobility of poly(ethylene butylene) chains in a direction normal to the film increases and reaches an equilibrium state at around K = 4.5. The change in gas permeability of the stretched films can be explained using a deformation model for the SEBS matrix. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39386.     

Zeolite nanocrystals prepared from zeolite microparticles by a centrifugation-assisted grinding method

Different sizes of zeolite nanocrystals were fabricated from zeolite microparticles using a centrifugation-assisted grinding method. The zeolite nanocrystal formation can be attributed to the Al₂O₃ bowl mill generation of mechanical stress that fractured zeolite microparticles into smaller fragments. In the present study, the smaller fragments had a wide distribution of size and morphology. Therefore, different sizes of zeolite nanocrystals could be recovered from these smaller fragments by varying the centrifugation process. Zeolite nanocrystal product yields were measured by periodically recovering the nanocrystals from the smaller fragments based on milled zeolite powder. The larger crystals of zeolite were typically irregular in shape, whereas the smaller zeolite nanocrystals tended to be spherical. High product yield of the zeolite nanocrystals was obtained by periodically removing nanocrystals from the milled zeolite powder and recycling the large zeolite particles. Thus, the results from this new hybrid process suggest that it can be used to fabricate differing sizes of zeolite nanocrystals. In addition, the size of the recovered zeolite nanocrystal products was narrow, and the initial zeolite nanocrystal structure was not destroyed by the mechanical stress.     

Preparation of a novel bimodal catalytic membrane reactor and its application to ammonia decomposition for COx-free hydrogen production

A novel bimodal catalytic membrane reactor (BCMR) consisting of a Ru/γ-Al₂O₃/α-Al₂O₃ bimodal catalytic support and a silica separation layer was proposed. The catalytic activity of the support was successfully improved due to enhanced Ru dispersion by the increased specific surface area for the γ-Al₂O₃/α-Al₂O₃ bimodal structure. The silica separation layer was prepared via a sol–gel process, showing a H₂ permeance of 2.6 × 10⁻⁷ mol Pa⁻¹ m⁻² s⁻¹, with H₂/NH₃ and H₂/N₂ permeance ratios of 120 and 180 at 500 °C. The BCMR was applied to NH₃ decomposition for CO_x-free hydrogen production. When the reaction was carried out with a NH₃ feed flow rate of 40 ml min⁻¹ at 450 °C and the reaction pressure was increased from 0.1 to 0.3 MPa, NH₃ conversion decreased from 50.8 to 35.5% without H₂ extraction mainly due to the increased H₂ inhibition effect. With H₂ extraction, however, NH₃ conversion increased from 68.8 to 74.4% due to the enhanced driving force for H₂ permeation through the membrane.     

Absolute quantitation of quercetin and the glycosides in natural food additives by quantitative NMR

We are developing a simple absolute quantitation method for organic compounds, by means of quantitative nuclear magnetic resonance (qNMR), with traceability to the International System of Units (SI units). The qNMR method was applied to the absolute quantitation of rutin, isoquercitrin and quercetin in natural food additives, rutin (extract), enzymatically decomposed rutin extract and quercetin, and those compounds as commercial reagents. In this study, 1,4-bis-(trimethylsilyl)benzene-d(4) (1,4-BTMSB-d(4)) whose purity was precisely evaluated on the basis of metrology, was newly used as a qNMR reference material, to be added to the sample solution as an internal standard. The contents of quercetin and quercetin glycosides were calculated from the ratio of the signal intensities of each aromatic proton at the 2' position of the three compounds (these are observed at different chemical shifts) to the eighteen protons of the six methyl groups on 1,4-BTMSB-d(4) used as a qNMR reference material. Rapid and simple qNMR method with only one step process was carried by using 1,4-BTMSB-d(4). It was demonstrated that the purities of rutin, isoquercitrin and quercetin can be separately determined by qNMR without the need for a separation process or reference materials for all the target compounds.     

Diagnosis of Electric Power Apparatus using the Decision Tree Method

To diagnose the electric power apparatus, the decision tree method can be a highly recommended classification tool because it provides the if-then-rule in visible, and thus we may have a possibility to connect the physical phenomena to the observed signals. The most important point in constructing the diagnosing system is to make clear the relations between the faults and the corresponding signals. Such a database system can be built up in the laboratory using a model electric power apparatus, and we have made it. The next important thing is the feature extraction. We used ø - V - n patterns and POW patterns for feature variables, and feature extraction is made by the extended moments, usual moments, and the parameters in the underlying distributions such as the generalized normal distribution and the Weibull distribution. By simple arrangements, we will be able to classify the faults and noise with high accuracy such that the misclassification rate is lower than 5%. If we set appropriate pre-processing procedure carefully, we might have a possibility of classification accuracy of less than 2%. Therefore, the decision tree with adequate feature extraction is considered to be a promising method as one of the classification tools     

Selective Triplet–Singlet Förster-Resonance Energy Transfer for Bright Red Afterglow Emission

Förster-resonance energy transfer (FRET_T-S) from the lowest excited triplet state (T₁) of a donating sensitizer to a fluorescence acceptor can be used to obtain bright room-temperature afterglow emission at long wavelengths. However, the energy transfer from the lowest excited singlet state of the donor to the acceptor is an undesirable deactivation pathway that prevents FRET_T-S. Herein, heteroatoms in chromophores are shown to allow selective and efficient FRET_T-S for enhanced triplet emission for bright room-temperature afterglow emission at long wavelengths. Different transition characteristics between the lowest singlet excited state and triplet states in heteroatom-containing chromophores accelerate triplet generation, enabling near-zero fluorescence yields. Out-of-plane vibrations of the heteroatoms in aromatic fused rings greatly enhance the radiative rate from T₁ by a factor of 88 relative to non-heteroatom-containing fused chromophore. The compatibility of the near-zero fluorescence and the enhanced triplet emission in a heteroatom-containing fused chromophore enable selective and efficient FRET_T-S pathways, resulting in room-temperature red afterglow emission with a yield of 17%. The bright emission at long-wavelengths allows distinguishable, multiple spectral signals in ambient white light.     

Translation among CNFs, characteristic models and ordered binary decision diagrams

We consider translation among conjunctive normal forms (CNFs), characteristic models, and ordered binary decision diagrams (OBDDs) of Boolean functions. It is shown in this paper that Horn OBDDs can be translated into their Horn CNFs in polynomial time. As for the opposite direction, the problem can be solved in polynomial time if the ordering of variables in the resulting OBDD is specified as an input. In case that such ordering is not specified and the resulting OBDD must be of minimum size, its decision version becomes NP-complete. Similar results are also obtained for the translation in both directions between characteristic models and OBDDs. We emphasize here that the above results hold on any class of functions having a basis of polynomial size.