Outstanding Paper Awards Subcommittee of Journal of Chemical Engineering of Japan has assessed the 187 papers published in volume 40 into 2007, and the editorial board finally selected the four papers for JCEJ Paper Awards of 2007; those are the papers on “Incorporation of Capillary-Like Structures into Dermal Cell Sheets Constructed by Magnetic Force-Based Tissue Engineering,” “Water Quality Control for Intensive Shrimp Culture Ponds in Developing Countries Using Ammonia-Nitrogen Uptake by Seaweed,” “Numerical Analysis of the Mixing Process of a Heterogeneously Viscous System with High Concentration Slurry Liquids in a Stirred Vessel,” and “Production of Fuel Gas through the Hydrothermal Gasification of Wastewater Using Highly Active Carbon-Base Catalyst.”
The characteristics of liposome formation in a micro-tube have been studied to develop a novel production method that forms the liposomes with a desired size homogeneously. In this method, the inner wall of the micro-tube was used to spread the liposomal lipid on. Then, instead of conventional rigorous agitation, an aqueous solution was fed through the tube, which peeled off the thin lipid layer formed liposomes. This resulted in a sharp peak in the size-distribution profile, and the size of liposomes was found to be dependent on the flow velocity and on the micro-tube size. Moreover, the yield of the liposomes of the desired size in our method was much higher than that in the conventional method, because our method produced liposomes uniform in size. From these findings, we concluded that the friction drag in the micro-tube is applicable for the efficient production of liposomes and a microfluidics device consisting of micro-tubes is a promising tool in the production of liposomal formulations.
A new semi-theoretical approach for prediction of gas holdups in the homogeneous flow regime is suggested. The model is based on two different expressions for the gas–liquid interfacial area. It is argued that in the case of oblate ellipsoidal bubbles (formed in the homogeneous regime) some correction factor should be introduced in order to render both expressions equivalent. The correction term is correlated to Eötvös number and a dimensionless gas density ratio. The method was capable of predicting 386 experimental gas holdups measured in 21 organic liquids, 17 liquid mixtures and tap water with an average relative error of 9.6%.
The effect of multi-inlet flow on particle classification performance of hydro-cyclones was examined experimentally and via a simulation study. The type A cyclone with two flow inlets had smaller cut size and sharper separation performance compared to the standard cyclone. Numerical simulation indicated a nearly uniform rotational fluid velocity profile for the type A cyclone. On the other hand, the standard cyclone showed a non-uniform rotational velocity profile near the inlet part of the main flow. The type B cyclone with a small additional flow injection area, showed smaller cut sizes as the flow rate of the additional flow increased. The type B cyclone showed smaller cut size compared to the standard cyclone without the additional flow. The experimental data of the type B cyclone agreed with the proposed new model based on horizontal particle separation theory. The use of a multi-inlet cyclone is quite effective at improving particle separation performance compared to the standard one.
An analysis of the water permeability of a molecular recognition ion gating membrane was performed. The ion gating membrane shows outstanding water permeability switching properties in response to specific ion concentrations, using an ion-responsive polymer consisting of thermosensitive poly(N-isopropylacrylamide) and crown ether moieties, grafted onto a porous substrate pore surface. To investigate the precise properties of the membrane, a polycarbonate track-etched membrane having straight pores with a narrow pore size distribution was used as the substrate, and the ion responsive polymer was grafted onto its pore surfaces. The gating property of the prepared membrane was examined as a function of temperature, specific ion concentration, and filling ratio. Estimates of pore size and dimension of the grafted polymer were obtained using the Hagen–Poiseuille equation. We found that the grafted ion-responsive polymer shows drastic dimensional changes in response to temperature and specific ion concentrations.
Internally heat-integrated distillation columns (HIDiCs) are one of the most attractive alternatives for the conventional distillation columns (CDiCs) since HIDiCs have very high potential to separate a mixture with smaller energy consumption compared to CDiCs. In order to prove the energy saving characteristics of HIDiCs, a pilot plant of the HIDiC was constructed for the separation of multicomponent hydrocarbon mixture. The HIDiC pilot plant was operated at zero external reflux condition, and achieved more than 50% reduction in the energy consumption compared to the simulation results of the existent CDiC.
Titanium oxide (TiO2) thin films were grown on Si(100) substrates using the chemical vapor deposition (CVD) of titanium tetra isopropoxide (TTIP; Ti(OCH(CH3)2)4). The distribution of the growth rate in the reactor and the step coverage of films grown in the range 593–1173 K could was using our “simple reaction model.” The TTIP changed into TiO2 directly via a surface reaction. The surface reaction rate constant was determined by comparing the step coverage of grown and simulated films. The activation energy of the surface reaction was 212 kJ/mol (T < 710 K).
In this paper, a new adaptive single-neuron (ASN) controller is proposed based on the just-in-time learning (JITL) technology for nonlinear process control. To mimic the traditional PID controller, a single neuron is employed in the proposed controller design strategy. Incorporated with the neural network’s learning ability, the proposed controller can control the process adaptively through the updating of its parameters by the adaptive learning algorithm developed and the information provided from the JITL. Compared with the neural network based PID controller designs previously developed, ASN controller is more amenable to on-line implementation. Simulation results are presented to illustrate the proposed method and a comparison with its conventional counterparts is made.
The effect of medium component on manganese peroxidase production by white rot fungus strain L-25 was investigated using a response surface method (RSM). The Mn2+ and Polypepton concentrations had a strong influence compared to the initial pH. The Mn2+ concentration affected the specific activity, while the addition of Polypepton elevated the extracellular protein concentration in the medium. Since the MnP activity depended on both the specific activity and extracellular protein concentration, the MnP production could be expressed as a function of both the Mn2+ and Polypepton concentrations. Based on the response surface plot, the optimum medium components were predicted as 1.0 mM Mn2+, 45 g/L Polypepton and initial pH of 6.2. Large amounts of MnP (about 30 U/mL) were obtained using the optimized medium. This is the highest value reported up to now.
Baculovirus re-infection to already-infected insect cells was assessed by comparing the binding of radio-labeled AcMNPV to Sf-9 cells with the expression of marker proteins, β-galactosidase and variant of green fluorescent protein, respectively coded in the baculoviruses. The binding of baculoviruses to virus-infected Sf-9 insect cells was significantly inhibited with the elapse of time post primary infection (ppi) and completely inhibited by 12 h-ppi. The protein analysis suggested that baculoviruses bound to already-infected cells were internalized into the cells and routed for protein expression. However, the yield of protein coded in 2nd viruses (for re-infection) decreased with delaying re-infection time from the infection with primary viruses, and the expression of 2nd virus protein was not determined on the re-infection at 12 h-ppi. On the contrary, the expression of primary virus protein was inhibited by bringing forward the time of re-infection with 2nd viruses, giving nearly a steady level of total volumetric productivity.
The tube wastage profiles of water walls are discussed in a commercial CFB furnace with two gas exits. The lateral profile of wear rate confirms that tube wastage is influenced mainly by secondary flow, stronger toward the center than in the corners, and somewhat by the wing walls and gas exits. The effect of two superposed secondary flows of the second kind, one caused by the shape of the entire freeboard cross-section and the other by sections between the wing walls, could also be confirmed in lateral profiles of tube erosion rate on the wall connected with wing walls. Appreciable tube erosion rate was confirmed near the center of the rear wall at lower heights and near the center of both sidewalls at heights above the gas exit level. Wastage of wing walls increased with distance into the interior of the furnace.
The process energy efficiency of supercritical water gasification was determined by a detailed calculation of the energy balance. Ten tons (wet) per day of chicken manure, the moisture content of which was adjusted, was employed as the model feedstock. An efficiency ratio of 70% was obtained for chicken manure having a water content of 80%. The key operating parameters for ensuring high process energy efficiency were the heating value of feedstock and heat recovery efficiency. This result, along with the heat exchanger efficiency measured in the pilot plant, clearly indicates the high potential of supercritical water gasification technology as a wet biomass gasification process.
1,4-Dioxane is an EPA priority pollutant found in contaminated groundwater and industrial effluents. The common treatment techniques are not effective for 1,4-dioxane degradation. Thus there is a need to find an efficient degradation method such as a photo-Fenton process and understand the degradation mechanism of 1,4-dioxane during such reactions. In this study, the effect of the reaction parameters such as initial concentration of 1,4-dioxane, H2O2 and FeSO4 dosages, and UV light intensity on 1,4-dioxane degradation has been examined. Under optimal conditions, over 95% of 1,4-dioxane is degraded by photo-Fenton (UV with H2O2 and FeSO4), while little 1,4-dioxane is degraded by FeSO4 alone. It was proposed that 1,4-dioxane was oxidized by OH radicals and sequentially led to formation of malonic acid, formic acid and acrylic acid. Based on the experimental results of 1,4-dioxane, the application of advanced oxidation processes (AOPs) appears to be a promising alternative for 1,4-dioxane removal in various environment systems.