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Volume 33 (2000)
- Issue 6 Pages 823-
- Issue 5 Pages 689-
- Issue 4 Pages 573-
- Issue 3 Pages 353-
- Issue 2 Pages 197-
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Volume 33, Issue 4
Displaying 1-17 of 17 articles from this issue
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Thermodynamics, Physical Properties and Molecular Simulation
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Masashi Yamamoto, Masaru Ishida2000 Volume 33 Issue 4 Pages 638-644
Published: 2000
Released on J-STAGE: April 29, 2004
JOURNAL RESTRICTED ACCESSA material-utilization diagram (MUD), which represents energy and exergy features of phenomena with concentration change, is applied to methanol synthesis. The ordinate of the MUD is ln pj or ln Kp, r, whereas the abscissa is njRT0 or γrRT0, where nj is the number of moles of component j and γr is the extent of r-th reaction. Hence, energy loss caused by the decrease in partial pressure and exergy gain caused by the increase in partial pressure of each individual component relevant to the chemical reaction are displayed by a rectangular area –nj, inRT0ln(pj, out/pj, in) on MUD. The graphical representation of features of chemical reactions gives us intuitive suggestions, which are helpful in improving the process. Based on the information shown on MUD, three improved systems, introduction of membrane separation, addition of CO2, and two-staged pressures for operation, are demonstrated.View full abstractDownload PDF (297K) -
Carmen E. Velezmoro, Alessandra L. Oliveira, Fernando A. Cabral, Anton ...2000 Volume 33 Issue 4 Pages 645-653
Published: 2000
Released on J-STAGE: April 29, 2004
JOURNAL RESTRICTED ACCESSData of water activity in sugar solutions (of sucrose, glucose, fructose, and maltose) were obtained experimentally utilizing a dew point device (Aqua-Lab CX-2) at temperatures of 25, 30, and 35°C, and atmospheric pressure. The thermodynamic models of group contribution (UNIFAC, ASOG) and of equations of state (EOS PR/Classic; EOS PR/SV) were used for modeling and predicting water activity in these solutions. A single set of parameters was obtained for the temperatures tested by fitting the UNIFAC and ASOG models to the experimental data; equations of state were used to determine binary interaction parameters for water-sucrose, water-glucose, water-fructose, and water-maltose. Water activity was predicted for a quaternary mixture (sucrose, glucose, fructose and water), with average relative deviations of 0.5% and 1.3% for the EOS PR/SV and EOS PR/Classic, respectively. For the group contribution methods, the deviations were 0.48% for the ASOG and 0.52% for the UNIFAC.View full abstractDownload PDF (1393K) -
Akihisa Shioi, Ryuji Nagaoka, Yusuke Sugiura2000 Volume 33 Issue 4 Pages 679-683
Published: 2000
Released on J-STAGE: April 29, 2004
JOURNAL RESTRICTED ACCESSDynamic interfacial tension at liquid/liquid interface was measured. Surfactants were supplied to the measured point by a transverse mass-transfer induced by Marangoni instability, and we could make a local interface with surfactants where adjacent bulk phases contained almost no surfactant. The dynamics were dominated by desorption kinetics. A simple model was proposed to explain the results. Attractive interaction between surfactants at the interface was estimated by the model and the experiments.View full abstractDownload PDF (129K)
Transport Phenomena, Fluid Mechanics and Mixing
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Shinichi Ookawara, Kohei Ogawa2000 Volume 33 Issue 4 Pages 582-590
Published: 2000
Released on J-STAGE: April 29, 2004
JOURNAL RESTRICTED ACCESSBlood flow behavior around the arteriosclerosis region, which is often recognized as stenosis of the blood vessel, has been paid much attention of late.
In this study, the flow properties of Newtonian and non-Newtonian blood analogous fluid are investigated in a straight pipe with sudden construction and expansion, which is a model of arterial stenosis.
It is found that introducing pulsation is more effective for the recover of velocity profile downstream of stenosis rather than increasing the Reynolds number in laminar flow range for both fluids.
It is distinctive that the velocity profile is not sensitive to Reynolds number for both steady and pulsating flow regimes of non-Newtonian fluid. Since the recovery of velocity profile means momentum transport by convection in the radial direction, mass transport is also expected to be enhanced by pulsation rather than by the increase of Reynolds number. For Newtonian fluid, however, Reynolds number should be higher than for non-Newtonian to achieve sufficient mixing because of the higher sensitivity.
Further, it is elucidated by wavelet analysis that the structure of momentum transport is substantially different in spite of the similarity of velocity profile at Reynolds number around 500. This analysis also suggests the superiority of pulsating flow of blood.View full abstractDownload PDF (822K) -
Qingfeng Yang, Jie Ding, Ziqiu Shen2000 Volume 33 Issue 4 Pages 591-596
Published: 2000
Released on J-STAGE: April 29, 2004
JOURNAL RESTRICTED ACCESSThe formation of scale on heat transfer surfaces in cooling water systems is a frequent engineering problem. The present paper deals with the scaling process of calcium carbonate on a copper modified heat transfer surface with low surface energy—electroless plating (ELP) surface. The induction period of calcium carbonate scaling is investigated. The results indicate that an ELP surface can reduce the scaling rate and prolong the induction period compared with a copper surface. The scaling rate increases and the induction period is reduced with increasing initial surface temperature and fluid velocity. During the induction period, calcite was formed on ELP surface under experimental conditions, the crystal grains formed on the ELP surface were larger in size than that formed on copper surface, and the distribution of the grains on the ELP surface was different between the upstream and downstream regions. There were more grains formed in the downstream region. The outmost surface morphology of calcium carbonate scale is also studied.View full abstractDownload PDF (1455K) -
Jun Fukai, Tetsushi Ozaki, Haruhisa Asami, Osamu Miyatake2000 Volume 33 Issue 4 Pages 630-637
Published: 2000
Released on J-STAGE: April 29, 2004
JOURNAL RESTRICTED ACCESSA mathematical model describing the deformation and solidification behavior of liquid droplets impinging on substrates is presented. The mathematical model is numerically solved using a finite element method. In the experiment, a molten tin droplet (2.2–4.3 mm diameter) impacts copper, stainless steel and glass substrates at various preimpact velocities (1.4–4.0 m/s). The values of the heat transfer coefficient at the droplet/substrate interface are evaluated by comparing the calculated splat diameters to the experimental ones. The estimated values are within the previously reported ranges. The model almost predicts the Weber number dependence of the experimental splat diameters. The time variations of the numerical splat diameters also agree with the experimental results. The simulation reveals that the frozen layer at the splat edge, rather than at the center region, affects deceleration of the droplet spreading. The effect of the solidification on the splat diameter is explained from the freezing rate at the splat edge.View full abstractDownload PDF (795K) -
Shinichi Ookawara, Kohei Ogawa, Norman Dombrowski, Esmail Amooie-Foume ...2000 Volume 33 Issue 4 Pages 675-678
Published: 2000
Released on J-STAGE: April 29, 2004
JOURNAL RESTRICTED ACCESSIt is shown that the entry flow of a Bingham fluid is not fully developed at the axial position where the center line velocity reaches 99% of the fully developed value, which is the classical definition. Therefore, the entry length of the Bingham fluid is determined based on the newly expanded definition in this study, viz., the axial length where the velocity at the radial position of 95% of plug radius, reaches 99% of the fully developed value. For a power law fluid, the entry length is determined based on the classical definition.
In order to obtain the corrected Reynolds number Re*, Ito’s method is employed in this study. It is shown that the entry lengths of Newtonian, Bingham and power law fluids are correlated by the same equations in the range of Re* < 20.View full abstractDownload PDF (146K)
Separations
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Mikiya Tanaka, Mikio Kobayashi, Junji Shibata2000 Volume 33 Issue 4 Pages 573-581
Published: 2000
Released on J-STAGE: April 29, 2004
JOURNAL RESTRICTED ACCESSThe effects of the extractant concentration, CHAo, and the flow rate of the organic phase, S, on the metal recovery in a steady-state countercurrent multi-stage metal solvent extraction-stripping process (ESP) using cation-exchange reagents have been assessed by computer simulation. The results show that, with increasing CHAo or S, (i) the recovery fraction monotonically increases when the number of stages in the extraction or stripping section (N or N′, respectively) is unity and (ii) the recovery fraction first increases, then reaches a maximum, and thereafter very slowly decreases when N and N′ are larger than unity. The optimum combination of CHAo and S will be determined by using the equi-recovery-fraction and equi-operating-cost curves. In order to obtain in-depth understanding of the simulation results, steady-state local linearization (SLL) analysis which theoretically considers the infinitesimal variations in the metal concentrations in each stage caused by the infinitesimal variation in the operational parameters has been done. As a result, it is proved that the balance between the quantities ψ (CHAo) of the extraction and stripping sections determines the trend of the recovery fraction with CHAo, where ψ (CHAo) is the partial derivative of the metal molarity in the organic phase at the outlet of the extraction or stripping section with respect to CHAo: At the maximum recovery fraction, these values are equal to each other. Similar results are obtained also in the effect of S. Furthermore, it is proved that, with increasing CHAo or S, (i) the maximum of the recovery fraction never appears when N or N′ is unity and (ii) the decrease in the recovery fraction after reaching the maximum is much slower than the increase before reaching the maximum when N and N′ are larger than unity.View full abstractDownload PDF (288K) -
Hamid Reza Mortaheb, Yoichi Iimuro, Hitoshi Kosuge, Koichi Asano2000 Volume 33 Issue 4 Pages 597-604
Published: 2000
Released on J-STAGE: April 29, 2004
JOURNAL RESTRICTED ACCESSAn experimental study on separation performance of a sieve tray column in ternary distillation is made under total reflux conditions with different tray specifications. The effects of operation conditions, tray specifications, and feed concentration on the clear liquid height and mass transfer rate are studied. The dimensionless volumetric vapor phase diffusion flux is correlated with the free area and Reynolds number. Simulation of separation performance of tray column was carried out using the proposed correlations for heat and mass transfer rates and clear liquid height. Predicted values of concentration agree with the experimental data of the present study and some previous works.View full abstractDownload PDF (417K) -
Akihiro Tomita, Tatsuo Kanki, Tsuyoshi Asano, Noriaki Sano2000 Volume 33 Issue 4 Pages 661-664
Published: 2000
Released on J-STAGE: April 29, 2004
JOURNAL RESTRICTED ACCESSIn the process of extraction of the rare earth metals europium and samarium by D2EHPA, we find that solid films form at the organic/aqueous interface. For extraction solution systems of europium and samarium, we specified concentration zones where the solid films should form, and show that the formation of the solid films occurs at the specific zones of hydrogen ion and extractant concentrations. We also determine the atomic constituents of the solid films by inductively coupled plasma emission spectroscopy, and find that the solid films are crystals composed of neutral 1:3 intermediate complexes. We further investigate film formation in the extraction solution system that contains two lanthanide elements, europium and samarium. We determine the atomic ratio of the solid film, and show that the atomic ratio takes the value which is near to that predicted from the separation coefficient in the organic/aqueous solution system.View full abstractDownload PDF (771K) -
Kosuke Araki, Masahiro Yoshida, Kazuya Uezu, Masahiro Goto, Shintaro F ...2000 Volume 33 Issue 4 Pages 665-668
Published: 2000
Released on J-STAGE: April 29, 2004
JOURNAL RESTRICTED ACCESSNeodymium (Nd3+)-imprinted polymers were prepared by the surface template polymerization technique. Two types of phosphonates were utilized as functional molecules. These Nd(III)-imprinted polymers were applied to the mutual separation of lanthanides; La(III) and Nd(III). The relationship between the imprint effect and the chemical properties of the functional molecules was investigated concerning the performance of the Nd(III)-imprinted polymers. A high interfacial property derived from the structure of the functional molecule, was found to be essential for creating high selectivity and high adsorption ability on the Nd(III)-imprinted polymers.View full abstractDownload PDF (126K)
Particle Technology and Fluidization
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Hiroyuki Kage, Koichi Kawaji, Hironao Ogura, Yoshizo Matsuno2000 Volume 33 Issue 4 Pages 605-611
Published: 2000
Released on J-STAGE: April 29, 2004
JOURNAL RESTRICTED ACCESSAttrition experiments with granular slugs were performed in a fluidized bed. A single horizontal nozzle was equipped on the sidewall of the fluidized bed in order to distinguish the effect of jet gas flow on attrition from the auxiliary fluidizing gas supplied from the distributor. The analysis was mainly focussed on the change in the granular slug weight. Reduction of particle size was mainly due to the attrition of its surface or irregularities, and breakage into two or more small particles was not observed.
A new attrition model, where the generation rate of fines is assumed to be in proportion to the weight of particle, and the effect of fluidizing gas supplied from the distributor on the attrition was assumed to be neglected, is proposed. The measured attrition data were correlated well by this model, and its reliability was examined. The coefficient K included in the proposed model, which is concerned with energy transfer to attrition, is almost independent of the initial weight of particles, and increases with jet flow rate.View full abstractDownload PDF (464K) -
Hidehiro Kamiya, Akira Kimura, Masayuki Horio, Jonathan Seville, Esko ...2000 Volume 33 Issue 4 Pages 654-656
Published: 2000
Released on J-STAGE: April 29, 2004
JOURNAL RESTRICTED ACCESSThe increase in the cohesive properties of fly ash under elevated temperature conditions up to 1123 K, was investigated by a diametral compression test of ash powder pellets. Under conditions of relatively low temperatures (below 1000 K), the strength of ash powder pellets increases gradually in proportion to temperature. A remarkable increase in strength of the powder pellets is observed in the high temperature range above 1123 K. At these high temperatures, plastic deformation (during a diametal compression test) and enhancement in the time dependent on increase in fracture load of ash powder pellets is observed.View full abstractDownload PDF (825K)
Process Systems Engineering
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Wei Wu2000 Volume 33 Issue 4 Pages 617-629
Published: 2000
Released on J-STAGE: April 29, 2004
JOURNAL RESTRICTED ACCESSThis paper concerns a class of nonlinear systems with nonlinear inputs. Using the step-by-step design procedure and stable inversion conditions, the proposed dynamic state feedback with numerical implementation can provide asymptotic output regulation. Based on the two-input control scheme and an extended linearization technique, closed-loop stability can be guaranteed. Through a complete theoretical analysis of a two-input process, the additional control freedom of such design can enhance both system performance and robustness. Under a parametric transformation and a step-by-step design procedure, a large control action for suppressing unknown disturbancess can be distributed, and a two-time-scale linearized model can be established. Finally, the proposed methodologies are all evaluated through simulations for the control of two continuous-stirred tank reactors in series.View full abstractDownload PDF (341K)
Biochemical, Food and Medical
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Koreyoshi Imamura, Tetsuo Suzuki, Takayuki Tatsumichi, Shinya Kirii, M ...2000 Volume 33 Issue 4 Pages 657-660
Published: 2000
Released on J-STAGE: April 29, 2004
JOURNAL RESTRICTED ACCESSWater sorption and glass transition of four amorphous sugars (lactose, maltose, sucrose, and trehalose) containing bovine serum albumin (BSA) are investigated. Freeze-dried sugar-BSA samples equilibrated at several water activities ranging from 0 to 0.43 were prepared. Moisture content and glass transition temperature (Tg) were measured. For the all sugars, it is found that BSA lowers Tg at low water activity, and raises it at high water activity. It is also found that the difference between Tg of the sugar-BSA samples and that of the corresponding amorphous sugar samples (Tg0) depends mainly on Tg0.View full abstractDownload PDF (635K)
Safety, Environment and Energy
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Yutaka Tabe, Shuichiro Hirai, Ken Okazaki2000 Volume 33 Issue 4 Pages 612-616
Published: 2000
Released on J-STAGE: April 29, 2004
JOURNAL RESTRICTED ACCESSDissolving CO2 into the ocean by the pumping of liquid CO2 is a strategy to offset the buildup of atmospheric CO2. However, under the high-pressure, low-temperature conditions in the deep ocean a CO2 hydrate film quickly isolates the liquid CO2 from seawater thus suppressing dissolution. The thickness of the hydrate film is one of the most important parameters for understanding the mass transport mechanism through the hydrate film during the liquid CO2 dissolution. We suggest a new method for measuring the thickness of the hydrate film formed at the interface between the liquid CO2 and flowing water. Our method assumes that a unique thickness of hydrate film is kept through hydrate dissolution and growth at the water-, and liquid CO2-hydrate interfaces, respectively. When growth stops, the net dissolution allows estimation of the original hydrate thickness. Under the conditions of our experiment, the CO2 hydrate film thickness is about 0.4 μm.View full abstractDownload PDF (1852K) -
Hyun Ha Kim, Isao Yamamoto, Kazunori Takashima, Shinji Katsura, Akira ...2000 Volume 33 Issue 4 Pages 669-674
Published: 2000
Released on J-STAGE: April 29, 2004
JOURNAL RESTRICTED ACCESSAn experimental approach has been adopted to remove dioxins and other pollutants from incinerator flue gas in a pilot-scale experimental system. The main objective of this study is to investigate the combined system for simultaneous removal of gaseous pollutants and dusts. The combined gas cleaning system consists of a radiator, a scrubber and a wet-type electrostatic precipitator (ESP). Dioxins can be decomposed effectively using after-burners downstream of the incinerator by maintaining the gas temperature around 850 ± 20°C. Fractional removal rates for various kinds of dioxins (PCDDs + PCDFs) were measured in this study. When the combined system is used, dioxin removal rates of 90–92% are achieved over a wide range of initial concentrations of dioxins. The combined system is also found to be effective in the removal of NOx, SOx, HCl, and dust.View full abstractDownload PDF (158K)
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