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Nishi K. Bhardwaj,Nishi K. Bhardwaj,Surendra P. Singh 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.22 No.-
Recycled pulp contains large amount of fines having high surface area and amorphous cellulose. Thesefines adsorb water to large extent and dewatering rate is lower compared to virgin pulp. Selectivehydrolysis of these excess ultra fines through cellulase enzymes can be utilized for enhancing thedrainage rate. The concept of monocomponent cellulase treatment of recycled pulp for improvement indrainage and the understanding whether effectiveness depends on a specific type of cellulasecomponent (endoglucanase/cellobiohydrolase) is described. The improvement of 15–23% in pulpdrainability was achieved along with better paper properties.
Small-Angle Neutron Scattering Study on Defect-Controlled Polymer Networks
Nishi, Kengo,Asai, Hanako,Fujii, Kenta,Han, Young-Soo,Kim, Tae-Hwan,Sakai, Takamasa,Shibayama, Mitsuhiro American Chemical Society 2014 Macromolecules Vol.47 No.5
<P>Tetra-PEG gels are classified to near-“ideal” networks with significantly low inhomogeneities, which were confirmed by small-angle neutron scattering (SANS). In this study, we systematically introduced two types of defects into Tetra-PEG gels and investigated effects of defects on structure. First, we prepared defect-rich networks by simply reducing prepolymer concentration, and observed the evolution of network structure by time-resolved SANS during gelation process. In this case, both the scattering intensity and the correlation length increased with reaction time in the ϕ < ϕ* region, while they scarcely changed in the ϕ > ϕ* region. Here, ϕ and ϕ* are the polymer volume fractions at observation and that at chain-overlap concentration, respectively. Second, we prepared “<I>p</I>-tuned” Tetra-PEG gels by tuning the reaction probability, <I>p</I>, and soaked them in water to expose the inhomogeneities. It was revealed that SANS profiles of as-prepared gels did not change noticeably, while those of swollen gels systematically changed with decreasing <I>p</I>. On the basis of these results, we discuss the relationship between the defects of polymer network and inhomogeneities by using simple schematic pictures of polymer network.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/mamobx/2014/mamobx.2014.47.issue-5/ma402590n/production/images/medium/ma-2013-02590n_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ma402590n'>ACS Electronic Supporting Info</A></P>
Radial Thrust of Single-Blade Centrifugal Pump
Nishi, Yasuyuki,Fukutomi, Junichiro,Fujiwara, Ryota Korean Society for Fluid machinery 2011 International journal of fluid machinery and syste Vol.4 No.4
Single-blade centrifugal pumps are widely used as sewage pumps. However, the impeller of a single-blade pump is subjected to strong radial thrust during pump operation because of the geometrical axial asymmetry of the impeller. Therefore, to improve pump reliability, it is necessary to quantitatively understand radial thrust and elucidate the behavior and mechanism of thrust generating. This study investigates the radial thrust acting up on a single-blade centrifugal impeller by conducting experiments and CFD analysis. The results show that the fluctuating component of radial thrust increases as the flow rate deviates from the design flow rate to low or high value. Radial thrust was modeled by a combination of three components, inertia, momentum, and pressure by applying an unsteady conservation of momentum to the impeller. The sum of these components agrees with the radial thrust calculated by integrating the pressure and the shearing stress on the impeller surface. The behavior of each component was shown, and the effects of each component on radial thrust were clarified. The pressure component has the greatest effect on the time-averaged value and the fluctuating component of radial thrust. The time-averaged value of the inertia component is nearly 0, irrespective of the change in the flow rate. However, its fluctuating component has a magnitude nearly comparable with the pressure component at a low flow rate and slightly decreased with the increase in flow rate.
A New Blade Profile for Bidirectional Flow Properly Applicable to a Two-stage Jet Fan
Nishi, Michihiro,Liu, Shuhong,Yoshida, Kouichi,Okamoto, Minoru,Nakayama, Hiroyasu Korean Society for Fluid machinery 2009 International journal of fluid machinery and syste Vol.2 No.4
A reversible axial flow fan called jet fan has been widely used for longitudinal ventilation in road tunnels to secure a safe and comfortable environment cost-effectively. As shifting the flow direction is usually made by only switching the rotational direction of an electric motor due to heavy duty, rotor blades having identical aerodynamic performance for bidirectional flow should be necessary. However, such aerodynamically desirable blades haven't been developed sufficiently, since most of the related studies have been done from the viewpoint of unidirectional flow. In the present paper, we demonstrate a method to profile the blade section suitable for bidirectional flow, which is validated by studying the aerodynamic performances of rotor blades of a two-stage jet fan experimentally and numerically.
An Outlook on the Draft-Tube-Surge Study
Nishi, Michihiro,Liu, Shuhong Korean Society for Fluid machinery 2013 International journal of fluid machinery and syste Vol.6 No.1
If large pressure fluctuation is observed in the draft tube of a Francis turbine at part-load operation, we have generally called it draft-tube-surge. As occurrence of this phenomenon seriously affects the limit of turbine operating range, extensive studies on the surge have been made since proposal of surge-frequency criterion given by Rheingans. According to the literature survey of related topics in recent IAHR symposiums on hydraulic machinery and systems, in which state-of-the-art contributions were mainly presented, a certain review of them may be desirable for an outlook on the future studies in this research field. Thus, in this review paper, the authors' previous attempts for the last three decades to challenge the following topics: a rational method for component test of a draft tube, nature of spiral vortex rope and its behavior in a draft tube and cavitation characteristics of pressure fluctuations, are introduced together with other related contributions, expecting that more useful and significant studies will be accomplished in the future.
Structural Analysis of Lipophilic Polyelectrolyte Solutions and Gels in Low-Polar Solvents
Nishi, Kengo,Tochioka, Saki,Hiroi, Takashi,Yamada, Taihei,Kokado, Kenta,Kim, Tae-Hwan,Gilbert, Elliot Paul,Sada, Kazuki,Shibayama, Mitsuhiro American Chemical Society 2015 Macromolecules Vol.48 No.11
<P>Lipophilic polyelectrolyte gels capable of large swelling in low-polar solvents (3 ≤ ε ≤ 10) were developed by Ono et al. (Nature Mater.<x> </x>2007), where ε is the dielectric constant. These gels were prepared by introducing tetraphenylborate as a lipophilic anion (tetrakis(3,5-bis(trifluoromethyl)phenyl)borate; TFPB<SUP>–</SUP>) and tetraalkylammonium with long alkyl chains as a lipophilic cation (tetra(<I>n</I>-butyl)ammonium; TBA<SUP>+</SUP>) into a poly(octadecyl acrylate) (pODA) backbone chain. Here, we investigated the structure of the lipophilic polyelectrolyte gels and corresponding polymer solutions in CH<SUB>2</SUB>Cl<SUB>2</SUB> with small-angle neutron scattering (SANS) and dynamic light scattering (DLS). From SANS, it was revealed that individual pODA chain is regarded as a rod with the cross-section radius of 15 Å and the length of ca. 160 Å and is little changed by introduction of charges or cross-linking. In addition to this, it was revealed from SANS measurements that the second virial coefficient of pODA in CH<SUB>2</SUB>Cl<SUB>2</SUB> was positive. In combination with DLS measurements, we observed several characteristic features similar to polyelectrolyte aqueous systems such as (i) the clear appearance of slow diffusional motion in polymer solutions, (ii) an increase of diffusion coefficient in gels, and (iii) an increase of osmotic modulus in solutions and gels when ionic groups are incorporated in pODA. These experimental findings clearly show that [TBA<SUP>+</SUP>][TFPB<SUP>–</SUP>] dissociates enough and pODA, accompanying these ionic groups, acts as a polyelectrolyte even in a low-polar solvent such as CH<SUB>2</SUB>Cl<SUB>2</SUB> (ε = 8.9). It is concluded that the good compatibility of pODA with CH<SUB>2</SUB>Cl<SUB>2</SUB> and the introduction of dissociable ionic groups into pODA result in high-swelling capability of the lipophilic polyelectrolyte gels.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/mamobx/2015/mamobx.2015.48.issue-11/acs.macromol.5b00753/production/images/medium/ma-2015-00753f_0012.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ma5b00753'>ACS Electronic Supporting Info</A></P>
Development and use of New Materials Derived from Resource Plants
Nishi Kosaburo 한국자원식물학회 2001 한국자원식물학회 학술심포지엄 Vol.2001 No.-
It is necessary for governmental supporting polices to collect. management and maintain the genetic resource with respects of diversity of useful natural resource plant and domestic variety for plant industry. There are the main tasks of functional plant industry to develope the techniques of systemic management of genetic resources with sufficient life because of having the key of human's fate with life and death and being the valuable thing to be Investigation. collection and introduction of genetic resource with natural resource plants. Agriculture after WTO is putting an emphasis on the development of functional plants with highly competitiveness In world market under long term and organizing plants Genetic resource of plant in the official institution are maintaining and managing to be possible the regeneration and reproduction if necessary. and utilizing whoever need them.