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Now showing items 145 - 160 of 210

  • Preparation and characterization of hydrophilic surface modifier macromolecule modified poly (ether sulfone) photocatalytic membrane for phenol removal

    Salim, Noor Elyzawerni   Jaafar, Juhana   Ismail, A. F.   Othman, M. H. D.   Rahman, Mukhlis A.   Yusof, N.   Qtaishat, M.   Matsuura, T.   Aziz, F.   Salleh, W. N. W.  

    A modified poly (ether sulfone) (PES) by hydrophilic surface modifying macromolecules (LSMM) incorporated with oxygenated graphitic carbon nitride (OGCN) photocatalyst (PES/OGCN-LSMM) was successfully prepared as a hybrid photocatalytic membrane. The effect of solvent evaporation time during membrane fabrication was studied by focusing on the positioning of LSMM in order to provide the desirable properties of the PES/OGCNLSMM hybrid membrane for phenol removal performance by photocatalytic and separation. The PES/OGCNLSMM membranes exhibited a decreased value of contact angle as the solvent evaporation time increased. The SEM images revealed a dense top layer supported by finger-like structures underneath, which was formed for the membranes at 0-4 min solvent evaporation time, while a sponge-like microvoid structure was observed at 5 min of solvent evaporation time. It is interesting to highlight that as the evaporation time increased, the pure water flux decreased as the result of compact denser membrane. Benefitting the special feature of LSMM that tends to migrate upwards upon mixing, the LSMM effectively assisted OGCN photocatalyst to the top layer of the membrane. This was revealed by SEM top surface images that more OGCN photocatalyst particles were seen distributed on the dense top layer of the membrane upon longer solvent evaporation time supported by the membrane topography analysis. It was found that the phenol reduction by rejection and photocatalytic tests was the highest at 5 min solvent evaporation time, whilst water flux was the lowest. The obtained results showed that the LSMM has indeed assisted the positioning of OGCN towards the top layer of the membrane and consequently increased the photocatalytic activity of the membrane on phenol.
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  • The art of surface modification of synthetic polymeric membranes

    Khulbe, K.C.   Feng, C.   Matsuura, T.  

    The development in the area of surface modification of polymeric synthetic membranes since 2000 is reviewed. Many patents, articles, and reviews have been written on the development in the area of surface modification of polymeric synthetic membranes subjected to RO, UF, NF, gas separation (GS), and biomedical applications, mainly since 2000, but recently more attention has been given to the modification of their surfaces to obtain desirable results. In particular, most emphasis has been given to plasma treatment, grafting of polymers on the surface, and modifying the surfaces by adding SMMs (surface-modifying molecules). New additives are synthesized to make the polymeric membrane surfaces either to be more hydrophilic or hydrophobic, aimed at improvement in selectivity and permeability of the membranes for GS, NF, and RO. Improvement in antifouling by surface modification is also a popular topic in the membrane industries. In the last 8 years, tremendous research efforts have been made on the development of antifouling membranes. copy 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010.
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  • Effect of dispersion state of Cloisite15A (R) on the performance of SPEEK/Cloisite15A nanocomposite membrane for DMFC application

    Jaafar, Juhana   Ismail, A. F.   Matsuura, T.  

    The introduction of 2,4,6-triaminopyrimidine (TAP) into sulfonated poly(ether ether ketone) (SPEEK)/Cloisite15A(R) nanocomposite membranes were investigated for the purpose of maintaining low methanol permeability and suppressing swelling in direct methanol fuel cell (DMFC). SPEEK with 63% of degree of sulfonation (DS) was prepared by sulfonation of PEEK. Cloisite15A (7.5 wt %) along with various weight loading of TAP was incorporated into SPEEK matrix via solution intercalation method. The effect of TAP loading on the SPEEK/Cloisite15A/TAP morphology was studied. The beneficial impact of the SPEEK/Cloisite15A/TAP morphology on the physicochemical properties of the membrane was further discussed. Swelling behavior, ion exchange capacity (IEC), proton conductivity, and methanol permeability of the resultant membranes were determined as a function of Cloisite15A and TAP loadings. Uniform distribution of Cloisite15A particles in the SPEEK polymer matrix in the homogenous SPEEK/Cloisite15A/TAP nanocomposite membranes was confirmed by scanning electron microscopy and X-ray diffraction. The water uptake of the SPEEK nanocomposite membranes decreased dramatically in the presence of TAP. The significant selectivity of SP/7.5/7.5 nanocomposite membranes could indicate a potential feasibility as a promising electrolyte for DMFC. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
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  • Characterization and mechanical properties of polyacrylonitrile/silica composite fibers prepared via dry-jet wet spinning process

    Mataram, A.   Ismail, A. F.   Mahmod, D. S. A.   Matsuura, T.  

    Polyacrylonitrile (PAN)/silica composite fibers were fabricated by dry-jet wet spinning process. PAN/silica composite fibers were characterized with SEM and FIR. The former revealed that beads were formed and aggregated when silica content was more than 1 wt.%, while the latter confirmed the presence and increment of silica content. The tensile test was performed to obtain the mechanical properties of PAN/silica composite fibers, which showed an optimum Young's modulus at 5.94 GPa and tensile strength at 1.07 MPa at 1 wt.% silica. Therefore, the addition of silica particle at 1 wt.% has enhanced the mechanical properties of PAN/silica composite fibers. (C) 2010 Elsevier B.V. All rights reserved.
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  • Effect of different additives on the physical and chemical CO2 absorption in polyetherimide hollow fiber membrane contactor system

    Rahbari-Sisakht, M.   Ismail, A. F.   Rana, D.   Matsuura, T.  

    Porous asymmetric polyetherimide (PEI) hollow fiber membranes were fabricated via a phase-inversion method using ethanol, glycerol and acetone as the additives in the spinning dope. Also, hollow fiber PEI membrane without additives was fabricated. An aqueous solution of 1-methyl-2-pyrrolidone (80 wt.%) was used as bore fluid to prevent forming of an inner dense skin layer. The precipitation rate of the polymer dopes with the different additives was studied using cloud point measurement. The effect of the additives on the resulting membrane structure, surface porosity, pore size, critical water entry pressure, collapsing pressure and physical and chemical CO2 absorption performance by distilled water and NaOH (1 M) solution in a gas liquid membrane contactor system were investigated and compared. Cloud point diagrams indicated that the precipitation rate of the polymer dopes increased following the trend of ethanol > acetone > glycerol. Results of gas permeation tests showed that ethanol and glycerol as additives provided the membranes with the largest and smallest pore size, respectively. Moreover, all the additives resulted in an increase in the effective surface porosity. The cross-section of the membranes was examined via a scanning electron microscopy. Ethanol in the spinning dope provided the membrane structure with a sublayer with finger-like macrovoids, originating from the inner and outer surfaces of the hollow fiber and extending to the middle section of the hollow fiber wall, which resulted in a larger pore size and higher CO2 absorption rate than the other PEI hollow fiber membranes. (C) 2012 Elsevier B.V. All rights reserved.
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  • Cyclodextrin production in hollow fiber membrane reactor system: Effect of substrate preparation

    Sakinah, A. M. Mimi   Ismail, A. F.   Illias, R. M.   Zularisam, A. W.   Hassan, O.   Matsuura, T.  

    Production and separation of cyclodextrins (CDs) were assessed by employing an enzymatic membrane reactor (EMR) system. Comparison between gelatinized and ungelatinized tapioca starch was conducted to identify the pre-eminent type of tapioca starch via its reaction kinetic and the behavior of the ultrafiltration membrane in an EMR system. Results showed that the Michaelis constant value (K-m) for gelatinized tapioca starch was 47% lesser than the ungelatinized tapioca starch, which indicates higher affinity and strong substrate binding with the employed cyclodextrin glycosyltransferase (CGTase). However, gelatinized tapioca starch generated high membrane fouling, which demonstrated 60% higher hydraulic resistances and 7% lower percentage of flux recovery than ungelatinized tapioca starch, due to the cake deposition associated with large swollen tapioca starch molecules. (C) 2008 Elsevier B.V. All rights reserved.
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  • SANS study on rapid shrinking of comb-type poly(N-isopropylacrylamide) gels

    Annaka, M.   Sugiyama, M.   Matsuura, T.   Hino, M.   Fukunaga, T.   Hara, Y.   Okano, T.  

    The shrinking mechanism of comb-type poly(N-isopropylacrylamide) (NIPA) gel was investigated by small-angle neutron scattering (SANS). The SANS reveals that the microdomain structure with characteristic spacing of 460 angstrom is developed in the comb-type NIPA gel during the shrinking process. This suggests that the freely mobiles grafted chains show the rapid dehydration to make tightly packed globules with temperature, followed by the subsequent hydrophobic intermolecular aggregation of the dehydrated graft chains. These aggregations of the NIPA chains contribute to an increase in void volume, which allows the gel having a pathway of water. (C) 2004 Elsevier B. V. All rights reserved.
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  • 1.2 V mixed analog/digital circuits using 0.3 mum CMOS LSI technology

    Matsuura, T.   Yano, K.   Hiraki, M.   Sasaki, Y.   Miyamoto, M.   Ishii, T.   Nagai, R.   Nishida, T.   Seki, K.   Imaizumi, E.   Anbo, T.   Sumi, N.   Rikino, K.  

    Although dropping the supply voltage below 2 V is effective in reducing power consumption of LSIs for low-power systems, it has not been adopted because it severely degrades the system performance. This paper reports an experimental 1.2 V mixed analog/digital LSI based on 0.3 mum laterally-doped buried-layer (LDB) CMOS with plusmn0.4 V threshold voltages. Based on circuits such as a double feedforward phase-compensated amplifier and a self current cut-off sense amplifier, a 9b 2 MHz 4 mW pipelined A/D converter, a 16 kb 2 mW SRAM with 32 ns access time, and a basic logic gate with a 400 ps delay and 0.4 muW/MHz dissipation are realized
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  • A mixed analog/digital video signal processing LSI with on-chip AD and DA converters

    Okada, Y.   Matsumoto, Y.   Matsuura, T.   Shinmi, T.   Nishijima, H.   Masuda, M.   Ueda, S.  

    A special-purpose video signal processing (picture-in-picture processing) CMOS LSI with a 4-K gate digital section and on-chip video analog-to-digital and digital-to-analog converters has been realized. This mixed analog/digital system-on-chip VLSI (5.98 mm*6.86 mm) is designed using mixed-mode simulation and testing architecture and a noise suppression scheme; and is fabricated in a 2- mu m CMOS process. The mixed analog/digital integration is a very attractive LSI feature for video system applications and satisfies future needs of system-on-chip VLSIs.
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  • A high efficiency transmitter with a delta-sigma modulator and a noise cancellation circuit

    Matsuura, T.   Adachi, H.  

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  • A 185 K×6 field memory for TV/VTR pictures: Y Murakami, T Imai, K Inoue, K Hattori, Y Matsuura, M Hayashi, K Miki, Y Torimaru (Sharp. Corp., Nara, Japan) Proceedings of the IEEE 1988 Custom Integrated Circuits Conference (Cat. No. 88CH2584-1), Rochester, NY, USA, 16–19 May 1988 (New York, NY, USA: IEEE 1988), pp. 4.5/1–4

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  • Micro-optical switch with uni-directional I/O fibers

    Yokoyama, Y.   Ota, H.   Takeda, M.   Matsuura, T.   Chabloz, M.   Kaneko, S.   Uemura, A.  

    The authors have developed a new 2times2 micro-optical switch. The switch features a uni-directional input/output and a drive mechanism with latch functions. The newly developed structure combines two moving mirrors and a fixed V mirror to implement a 2times2 micro-optical switch with uni-directional input/output. Furthermore, the moving mirrors have been reduced in size by integrating the drive and latch functions by the use of magnetic shaft mirrors and driving coils. The micro-optical switch has been implemented as a module mounted in a ceramic package. The modular switch is 23.5times9.86times6.76 mm in size and provides a switching time of 1.3 ms for 15 V (469 mA) and an input pulse width of 1 ms. The reflectivity of the moving mirror is 98.6% (reflection loss: 0.06 dB) and the connection loss between the fixed mirror surfaces is 5.4 dB
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  • Sulfonated Polyethersulfone (SPES) - Charged Surface Modifying Macromolecules (cSMMs) Blends as a Cation Selective Membrane for Fuel Cells

    Muthumeenal, A.   Neelakandan, S.   Rana, D.   Matsuura, T.   Kanagaraj, P.   Nagendran, A.  

    Polyethersulfone (PES) was sulfonated by chlorosulfonic acid and concentrated sulfuric acid. The pure sulfonated PES (SPES) and modified SPES membranes were prepared by blending with different charged surface modifying macromolecules (cSMMs) namely, SPES/DEG-HBS, SPES/PEG-HBS, and SPES/PPG-HBS. Membranes were characterized for their morphology, physical properties, and electrochemical properties in order to evaluate these membranes as cation exchange membranes. The blended membranes showed an increase in hydrophilicity, water uptake, and proton conductivity compared to the pure SPES membranes. The highest values of water uptake and proton conductivity were obtained for the SPES/PPG-HBS blended membrane. Morphological studies revealed that the nodule size and surface roughness also influenced the water uptake, apart from the additional -SO3H group. Among the modified membranes, the SPES/DEG-HBS blended membrane exhibited a lower methanol permeability value of 8.895 x 10(-8) cm(2) s(-1) than the corresponding SPES membrane. The other two cSMM blended membranes showed higher methanol permeability values than SPES but still a smaller value than Nafion 117. The highest selectivity ratio (i.e., ratio of proton conductivity to methanol permeability) was obtained with the SPES/DEG-HBS cSMM blended membrane. These results showed that the SPES/cSMM blended membranes have promise for possible use as a cation exchange membrane in fuel cells and electrolyzer applications.
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  • Development of asymmetric polysulfone hollow fiber membrane contactor for CO2 absorption

    Rahbari-Sisakht, M.   Ismail, A. F.   Matsuura, T.  

    Porous asymmetric polysulfone (PSf) hollow fiber membranes were fabricated via wet spinning process. A mixture of 1-methyl-2-pyrrolidone (NMP) and distilled water (90 wt.% NMP) was used as bore fluid to make hollow fiber membranes without inner skin layers, whereas glycerol with 2 and 4 wt.% was used as additives to the spinning dope. The effect of the additives concentration on the structure, surface porosity, pore size, critical water entry pressure (CEPw), and CO2 absorption flux of the fabricated membranes were investigated. The cross-section and inner surface of the membranes were examined via scanning electronic microscopy (SEM). Using glycerol as the additive in the spinning dope provided the membrane structure with a thin finger-like and a thick sponge-like layer, which resulted in a high CEPw and CO2 absorption rate. Results of gas permeation tests showed with increasing glycerol concentration the N-2 permeance increase significantly and the wetting resistance decrease slightly. CO2 absorption by distilled water was conducted through the gas-liquid membrane contactors. By using 4% glycerol in the spinning dope, the PSf membrane showed a CO2 flux of approximately 57% higher than the PSf membrane with 2% glycerol at the absorbent flow rate of 200 ml/min. (C) 2011 Elsevier B.V. All rights reserved.
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  • Long-term reliability of iron base amorphous alloy cores for oil-immersed transformer

    Matsuura, T.   Nagayama, K.   Hagiwara, S.   Higaki, M.  

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  • Photochemistry on Solid Surfaces. (Reihe: Studies in Surface Science and Catalysis, Vol. 47). Herausgegeben von M. Anpo und T. Matsuura. Elsevier, Amsterdam 1989. XX, 585 S., geb. HFI. 360.00 — ISBN 0–444-87413–5

    Gerd Kaupp  

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