All issues
Volume 32 (2006)
- Issue 6 Pages 465-
- Issue 5 Pages 385-
- Issue 4 Pages 315-
- Issue 3 Pages 207-
- Issue 2 Pages 103-
- Issue 1 Pages 1-
Predecessor
Volume 32, Issue 4
Displaying 1-11 of 11 articles from this issue
- |<
- <
- 1
- >
- >|
Transport Phenomena and Fluid Engineering
-
Mio Isaji, Shinichi Ookawara, Kohei Ogawa2006 Volume 32 Issue 4 Pages 315-326
Published: 2006
Released on J-STAGE: September 04, 2006
JOURNAL FREE ACCESSTo derive a correlation equation for particle collision frequency with an impeller, the influence on the collision frequency of operational conditions such as impeller speed, particle size and solid–liquid density difference was examined based on a collision detection method using wavelet analysis. It was found that the particle often collided with the impeller at a time interval of several tens of milliseconds. In addition, the relation between the collision frequency and operational conditions was confirmed to depend on a threshold, which is set to detect the collisions. Therefore, the correlation equation was derived as a function of the threshold by experimentally establishing a model in which collision sound pressure has a log-normal distribution independently of operational conditions. Further, it was shown that the correlation equation could estimate collision frequency as a function of collision energy by establishing a relation between the threshold and the collision energy in future.View full abstractDownload PDF (963K) -
Toshiyuki Nonaka, Keisuke Anzo, Takeshi Okutani2006 Volume 32 Issue 4 Pages 327-330
Published: 2006
Released on J-STAGE: September 04, 2006
JOURNAL RESTRICTED ACCESSThe behavior of the interface deformation of a liquid film and the plug formation in a horizontal square pipe under microgravity was observed using the drop-shafts of the Microgravity Laboratory of Japan (MGLAB) and the National Institute of Advanced Industrial Science and Technology (AIST, RIIF).
The shape of the liquid meniscus attached to the lowest solid edge of the square pipe became unstable due to the transition from normal gravity to microgravity, and the liquid film broke into several lobes periodically. Liquid plugs were formed under microgravity in the pipe.
The experimental results of the average wavelength of the lobes spaced along the pipe were in reasonable agreement with the numerical results of the linear stability analysis for the circular pipe.View full abstractDownload PDF (469K)
Particle Engineering
-
Daisuke Nishiura, Atsuko Shimosaka, Yoshiyuki Shirakawa, Jusuke Hidaka2006 Volume 32 Issue 4 Pages 331-340
Published: 2006
Released on J-STAGE: September 04, 2006
JOURNAL RESTRICTED ACCESSThe influences of particle concentration and particle size distribution on particle behavior in hindered settling were investigated by a large-scale hybrid simulation involving a discrete element method for settling particles coupled with direct numerical simulation for fluid flow. The large-scale simulation is able to accept 100,000 particles with particle size distribution by using Earth Simulator. First, the simulation was carried out for the hindered settling of uniform size particles to confirm the reliability of proposed simulation method. The hindered settling velocity of particles decreased with increasing particle concentration, because of the increased drag force resulting from fluid flow induced by settling of particles. The relation between settling velocity of particles and particle concentration agreed with experimental observation.
For hindered settling of particles with two different sizes, the influences of the volume fraction and size ratio of the larger to the smaller particles on settling velocity were investigated by the simulation. The settling velocity of particles of both sizes decreased as the volume fraction of larger particles and the particle size ratio increased, because of the increased fluid velocity caused by the settling of particles. In the laminar flow range, the influence of collision between settling particles was negligibly small, because the contact force between particles was extremely less than the drag force.View full abstractDownload PDF (2354K) -
Daisuke Nishiura, Atsuko Shimosaka, Yoshiyuki Shirakawa, Jusuke Hidaka2006 Volume 32 Issue 4 Pages 341-347
Published: 2006
Released on J-STAGE: September 04, 2006
JOURNAL RESTRICTED ACCESSA new equation for estimating hindered settling velocity of a particle in a polydisperse suspension (in which particle sizes are distributed continuously) was derived by taking into account particle size distribution and particle concentration of the suspension. First, a basic equation of the settling velocity of a particle was proposed on the basis of theoretical consideration of the relation of particle concentration and particle size distribution to drag force and the velocity of fluid flow induced by settling of particles. To determine the unknown parameters included in the basic equation, the influences of particle concentration, the volume fraction of particles and particle size ratio on the settling velocity of particles of two different sizes were investigated by computer simulation using a discrete element method and direct numerical simulation. The influences of fluid velocity and drag force on the settling velocity of particles were represented as a function of particle concentration and particle size distribution, and then the new equation of hindered settling velocity was derived. The estimated values of hindered settling velocity of an individual particle in a polydisperse suspension of particles with continuous particle size distribution agreed well with the experimental values.View full abstractDownload PDF (474K)
Separation Engineering
-
Issei Fujiyoshi2006 Volume 32 Issue 4 Pages 348-351
Published: 2006
Released on J-STAGE: September 04, 2006
JOURNAL RESTRICTED ACCESSExperiments to separate nickel and chromium were carried out at 298 K on a column packed with porous glass powder (43–74 μm) using pyridine-2,6-dicarboxylic acid as an eluent. When 0.02 M PDCA eluent was used in the range of pH 1–4, nickel was not adsorbed but was eluted with the mobile phase liquid, and the retention volume of chromium was maximum near pH 2. The two metals were isocratically and perfectly separated in the ranges of pH 1.3–1.7 and pH 2.5–3.7. Since the retention volumes of these metals were independent of eluent flow rate in the range of 0.15–3.0 cm3/min, the separation time could be shortened by raising the flow rate. Separation was completed in 10 min by using 0.02 M PDCA (pH 1.5) and 13 min by using 0.03 M PDCA (pH 3.0) as an eluent.View full abstractDownload PDF (315K) -
Hideshi Seki, Aya Noguchi, Akira Suzuki, Norio Inoue2006 Volume 32 Issue 4 Pages 352-355
Published: 2006
Released on J-STAGE: September 04, 2006
JOURNAL RESTRICTED ACCESSBiosorption characteristics of cadmium and lead ions onto steam-sterilized Gram-positive bacteria, Lactobacillus Plantarum and Micrococcus Luteus, were determined. A metal-binding model considering the acid-dissociation and metal-binding reactions of acidic sites on/in the bacteria was applied to explain the experimental results. The results showed that the biosorption of bivalent metal ions onto these bacteria was due to monodentate binding to two different types of acidic sites: carboxylic and phosphatic. L. plantarum had 1.5-fold more metal binding sites than M. luteus, but the metal-binding constants of M. luteus were 2–5-fold larger than those of L. plantarum.View full abstractDownload PDF (320K)
Chemical Reaction Engineering
-
Toshiyuki Nonaka, Jumpei Okuno, Taku Michael Aida, Kiyotaka Hatakeda, ...2006 Volume 32 Issue 4 Pages 356-362
Published: 2006
Released on J-STAGE: September 04, 2006
JOURNAL RESTRICTED ACCESSA continuous-flow reactor system for chemical conversions in supercritical water under superhigh pressure (above 100 MPa) has been developed. An aqueous solution was mixed with preheated water in a swirl-injection mixer. At the mixing point, the solution was rapidly heated to its reaction temperature and the reaction was initiated. The residence time in the tubular reactor was less than 1 s. After passing through the reactor, the solution was quickly cooled with a cooling water jacket to terminate the reaction. Superhigh pressure of the reactor system was controlled at the sampling point using back-pressure regulators.
Water-soluble organics (glucose, fructose, etc.) can be converted into useful intermediates and chemicals (glyceraldehyde, 5-hydroxymethylfurfural, lactic acid, etc.) in subcritical and supercritical water at 523–873 K, 20–200 MPa using this system.
As a preliminary study of conversions under supercritical pressure, the fluid behavior in the mixer was investigated using a three-dimensional simulation based on the finite volume method.View full abstractDownload PDF (1318K) -
Hiroshi Obuse, Shingo Yamada, Satoshi Nakai, Makoto Takada, Masaaki Ho ...2006 Volume 32 Issue 4 Pages 363-368
Published: 2006
Released on J-STAGE: September 04, 2006
JOURNAL RESTRICTED ACCESSIn order to clarify the factor related to the removal efficiency of nitrogenous compounds in supercritical water oxidation, the effects of molecular structure of nitrogenous compounds to be decomposed and organic substances as additives were investigated. The effect of molecular structure of nitrogenous compounds was examined by using ammonium carbonate, urea and formamide derivatives, and it was found that nitrogen removal efficiency tended to increase with the number of carbons bound to the nitrogen atom. A similar tendency was observed when methanol or other organic compound was added to the reaction system. The improvement of nitrogen removal efficiency was thought to be caused by the reaction of nitrogenous compounds with ammonia and radical species produced by the supercritical water oxidation of organic substances.View full abstractDownload PDF (490K) -
Yasuhito Kawase, Takayoshi Masuya, Keiji Yasuda, Masaaki Nakamura2006 Volume 32 Issue 4 Pages 369-371
Published: 2006
Released on J-STAGE: September 04, 2006
JOURNAL RESTRICTED ACCESSVOC decomposition by a combination of ultrasonic atomization and ozone irradiation was examined. Aqueous solutions of trichloroethylene (TCE) and dimethyl sulfoxide (DMSO) were used as samples to be decomposed, and gas containing ozone was sparged into the reactor. For the TCE solution, stripping was dominant, but ultrasonic irradiation was also found to contribute to the decomposition. For the DMSO solution, on the other hand, stripping hardly occurred. The contact between liquid droplets atomized by ultrasound and ozone in the gas phase greatly enhanced the decomposition performance.View full abstractDownload PDF (280K)
Biochemical, Food and Medical Engineering
-
Kazuhito Nagayama, Kana Fukuyama, Masanao Imai2006 Volume 32 Issue 4 Pages 372-375
Published: 2006
Released on J-STAGE: September 04, 2006
JOURNAL RESTRICTED ACCESSThe effect of gelatin species on the activity of Candida rugosa lipase immobilized in soybean lecithin microemulsion-based organogel (MBG) was investigated in the esterification of dodecanoic acid with butanol. The species of gelatin were Bloom number 75 and 225. In both gelatin systems, immobilized lipase activity was maintained well for 40 days in repeated batch reactions. The maximal reaction rate was obtained at a water concentration of 60% v/v and a gelatin concentration of 33.5% w/v for Bloom 75 system, while at a water concentration of 70% v/v and a gelatin concentration of 22.5% w/v for Bloom 225 system.View full abstractDownload PDF (283K)
Energy
-
Shiro Kajiyama, Fumio Takemura, Akira Yabe2006 Volume 32 Issue 4 Pages 376-383
Published: 2006
Released on J-STAGE: September 04, 2006
JOURNAL RESTRICTED ACCESSWe constructed and evaluated the process of the liquid-phase method methanol open cycle system. In this system, the methanol is decomposed by waste heat, and the pipe transportation of the decomposition gas is done, and it is made to burn in the heat demand area directly, and it converts into heat of combustion. It is an important element to clarify the selection of the catalyst which is optimum for the system construction, catalysis performance, catalyst life, recovery of the catalyst and behavior of the by-product of the catalyst in order to study the energy transfer system using chemical reaction. From liquid phase methanol decomposition experimental result, Cu–Cr–Mn–Ba catalyst which was optimum for the system construction of the liquid-phase method methanol open cycle system (heat of combustion increase ratio 1.2 at the lower heating value) was found. On the basis of the experimental result, system examination (473 K, 5.86–7.07 MPa) which built in turboexpander and Carina cycle was carried out, and system efficiency in the heat recovery system was estimated with 59.3–73.4% (Carina cycle; 10.6–12.2%) to generate electric power. The liquid-phase method methanol open cycle system can efficiently convert the thermal energy of industry waste heat into chemical energy of heat quantity of the fuel, and can transport over long distance the thermal energy in the condition without heat loss. It was indicated that the liquid-phase method methanol open cycle system was a system for conjugating for the effective utilization of energy resource.View full abstractDownload PDF (672K)
- |<
- <
- 1
- >
- >|