Production of lignin peroxidase by a white-rot basidiomycete, Phanerochaete chrysosporium, was investigated experimentally using polyurethane foam as a carrier of immobilized fungal mycelia. The immobilized cell culture using polyurethane foam as a carrier of mycelia yielded significantly greater lignin peroxidase activity than the conventional stationary liquid culture. The effects of operational conditions, such as the kind and number of polyurethane foam cubes, glucose concentration and temperature, on the lignin peroxidase production were examined. Addition of 0.05% Tween 80, 1 mM veratryl alcohol and 1 mM FeSO_4-·7H₂O greatly improved the production of lignin peroxidase up to 2,700 units/ml culture medium. The lignin peroxidase activity in this culture was about three times larger than that obtained from the culture cultivated in the absence of these additives. Step change incubation lowering the temperature from 37°C to 30°C over an incubation time of three days was carried out for the large scale production of lignin peroxidase, and this incubation gave the highest lignin peroxidase activity 3,800 units/ml culture medium.

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The measurements of mass fluxes in binary distillation of the nitrogen-oxygen and argon-oxygen systems in a wetted-wall column were made under total reflux conditions for a wide range of turbulent flows.
The observed diffusion fluxes of each components in binary distillation were found to be proportional to their concentration driving forces, whereas the observed mass fluxes were not. A new correlation for vapor phase diffusion fluxes in the nitrogen-oxygen and argon-oxygen systems was proposed.

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We have developed a symbolic verification method for determining the safety and operability of chemical process sequential control systems. The number of test cases required to verify a system grows exponentially as the number of components of the system increases. This state explosion problem limits our previous automatic verification method (Moon et al., 1992, Moon, 1994) to testing small systems. To mitigate this problem, we have adopted the Symbolic Model Verifier (SMV) which was originally developed by McMillan to test VLSI circuits. The method uses Boolean formulas to represent sets and relations in order to avoid building an explicit state transition graph which occupies most of the computer memory consumed for the computation. Ordered Binary Decision Diagrams are employed to manipulate the formulas efficiently in the model checking process. As a result, the SMV can verify large alarm systems including 10¹²¹ reachable states. The input language of SMV also makes the modeling of chemical processing systems as easy and less error prone processes. The method is demonstrated and the performance of the verifier is studied in a series of multiple alarm designs.

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The two-dimensional velocity and direction of liquid flow were measured in the downcomer of concentric airlift reactors by a cross-correlation method utilizing a three-electrode electrochemical probe. The process of eliminating the part of bubble signals was necessary and developed systematically. The optimum value of the distance between the microelectrodes was decided for the gas-liquid two-phase flow.
The circulation velocities obtained with this probe agreed with those by a solid tracer method. When the ratio of the diameter of the draft tube to that of the column was small (D_i/D_o = 0.29), circumferential components of the liquid velocity as well as vertical components were detected to be significant at higher superficial gas velocities.

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Direct ethanol production from delignified rice straw was performed continuously using a combination of two reversibly soluble-autoprecipitating enzymes, [Meicelase and Cellulase Y-NG were individually immobilized on hydroxypropyl methylcellulose acetate succinate (AS-L)] and Pichia stipitis cells. Cellulase Y-NG immobilized on AS-L (X-AS) as well as Meicelase immobilized on AS-L (M-AS) proposed previously (Hoshino et al., 1994) exhibited a sharper response for the solubility depending on the pH changes; insoluble below 3.5 and soluble above 5.0. When delignified rice straw was hydrolysed using two immobilized enzymes at a ratio of X-AS/M-AS = l, the amount of soluble sugars obtained was higher than that using M-AS alone. Moreover, both immobilized enzymes in an insoluble state had good self-sedimentation properties and were coprecipitated with a large portion of P. stipitis cells.
Ethanol production was performed continuously by a reactor system equipped with a mixing vessel and a separation vessel. Both immobilized enzymes and the yeast cells were separated continuously from a solution containing ethanol by co-precipitation in the separation vessel and they was returned to a main reactor for reuse. In continuous ethanol production from the rice straw, high ethanol productivity of up to 0.113 kg/(m³·h) was achieved at a dilution rate of 0.050 h^-1. This continuous fermentation system suggests potential for effective ethanol production from delignified rice straw.

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The transmission probabilities and the number of molecules reflecting from the wall were computed using a Monte Carlo method for free molecule flow through a conduit containing an orifice of zero thickness. The computed transmission probabilities were compared with a composite transmission rule and a series-resistance equation. The distribution of the molecular number density on the conduit wall along the conduit axis was determined by assuming that the ratio of the molecular number flux reflecting from the conduit wall to that entering into the conduit inlet corresponds to the ratio of the molecular number densities at each position. When the orifice was placed halfway down the length of the conduit, the composite rule and the series-resistance equation, respectively, agreed well with the computed transmission probabilities for the conduits with the aspect ratio L/R ≥ 10, and the cross-sectional area ratio of tube and orifice opening β ≥ 10, and for the conduit with β ≥ 40. The molecular number density distributions were symmetric with respect to the midpoint, and had a minimum in the upstream side and a maximum in the downstream side. The molecular number density distributions exhibited jumps across the orifice, as well as at the inlet and exit of the conduit.

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The present work aims at studying the application of the thermal integration Secondary Reflux and Vaporization (SRV) in extractive distillation. This technique is based on heat exchange between the rectifying and stripping sections, using the natural temperature difference between these two sections of the extractive distillation column for an ethanol/water/ethylene glycol mixture. The calculated results are compared with those relative to extractive distillation for an acetone/methanol/water mixture. A substantial reduction in the energy consumption is observed when comparing integrated columns with conventional ones.

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Interaction forces between a cleaved mica and the SiO₂ surface of an apex of an AFM probe in electrolyte solutions were measured using an Atomic Force Microscope (AFM). It is found that (1) the AFM is a powerful apparatus to measure in-situ the interaction forces between surfaces in solutions on the molecular level, (2) the long-range interaction force between surfaces is estimated well by the classical DLVO theory, (3) the magnitude of the short-range interaction force corresponds to the order of the hydration enthalpy of the ions in the solution. A possible model for the structure of water molecules and ions adsorbed on the surface was discussed.

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The optimum condition for alkaline leaching of roasted zinc concentrate has been studied. The increase in baffle number increased the leaching rate and there existed an optimum pulp density for the highest leaching rate. It was essential to secure complete suspension of particles with a minimum power consumption in designing a leaching reactor. It was required to decrease the vortex depth over complete suspension to increase the leaching rate. The agitation speed for complete suspension (N_s) decreased as the agitator diameter (D) increased, but the dependence of N_s on D increased as the clearance ratio increased.

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A difference of kinetics between powdered and pelletized catalysts for the reaction system obeying Lagmuir-Hinshelwood (L-H) type kinetics was experimentally and theoretically demonstrated. Liquid-phase hydrogenation of 1-methylnaphthalene (1-MN) was performed as a model reaction of hydrogenation of highly aromatic diesel oil feedstock. Using two types of batch autoclave reactors, kinetic data were obtained with powdered, cylindrical and trilobed commercial Co-Mo/γ-Al₂O₃ catalysts, in the range of 583–623K temperature (T) and 5.0–8.0 MPa total pressure (P), with feed liquids of 10 and 30 wt% initial concentration of 1-MN (F_MN) diluted in a C₁₄-C₁₆ normal paraffin mixture. The inhibition effect of 1-MN was clearly observed for the powdered catalyst. L-H type intrinsic kinetic equations including inhibition terms of hydrogen and 1-MN were established. On the other hand, the reaction with the pelletized catalysts behaved as a pseudo first order one with respect to the concentration of 1-MN in the case of lower F_MN. A kinetic model—a combination of intrinsic kinetics and intraparticle mass balance—with a tortuosity factor of 3.1 excellently represented the difference of kinetics, as well as the effect of T, P, F_MN and size and shape of catalyst, on the product yields over the pelletized catalysts. The difference of kinetics was also theoretically explained from the view of the contribution of intraparticle diffusion effects.

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MFI-type zeolite membranes were synthesized by hydrothermal reaction on the surface of porous α-alumina support tubes with different pore sizes. The zeolite membranes consisted of three zones: The top zone was a polycrystalline zeolite layer and the inner zone was a layer of α-alumina macropores, partially filled with deposits. The intermediate zone was a mixture of alumina particles and deposits. The morphology of the zeolite membranes was dependent on the substrates. The permeance of zeolite membranes formed on the substrate possessing pores of 150–170 nm under identical conditions ranged over two orders of magnitude. There was no definite relationship between n-butane/i-butane (n-C₄H₁₀/i-C₄H₁₀) permselectivity and permeance, although permeance was affected by the substrates. The n-C₄H₁₀/i-C₄H₁₀ permselectivity calculated from single-component permeances was in the range of 1.5~12 at 100°C, and the activation energy for the permeances was 11 kJ·mol^-1. The selectivity increased in the case of n-C₁₄H₁₀ separation from a mixture containing a small amount of i-C₄H₁₀. The zeolite membranes thus served as molecular-sieving for C₄ isomers.

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Mass transfer performance and mathematical modeling for the reversed micellar extraction of lysozyme was investigated in a rotating disc contactor (RDC) of 38 mm diameter. The diffusion model was used to describe the extraction performance. The model was solved numerically by changing parameters to fit the calculated two phase concentration profiles with the measured profiles using the Complex optimizing method. The axial dispersion coefficients of two phases and the overall mass transfer coefficients based on the continuous phase in the RDC were determined as parameters. It was found that the correlations for dispersion coefficients in the literatures cannot be used for both continuous and dispersed phases, but the values of mass transfer coefficients obtained from the diffusion model agreed with those of the previous correlations in the literatures fairly well. It is suggested that the diffusion model may be used for mass transfer prediction and column design for the reversed micellar extraction of proteins.

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Surface modification with thiols and redispersion into non-micellar solvents of CdS ultrafine particles prepared in situ in reverse micellar systems have been investigated. An excellent redispersion in pyridine is observed when the CdS ultrafine particles are prepared with 0.4 < y (=[S^2–]/[Cd²⁺]) < 0.9 owing to the binding of the added thiophenol molecules to the excess Cd²⁺ ions adsorbed to the surface of the CdS particles. The particle redispersion ratio, R, is defined as the ratio of absorbance of ultrafine particles redispersed in nonmicellar media to that of particles in the same amount of the original reverse micellar solution. As the time after CdS formation until the addition of thiophenol to the micellar solution (t_SH) increases, the redispersion ratio R into either pyridine or CH₂O₂ decreases. The emission at λ_em=570 nm of the formed CdS particles in reverse micellar solutions before adding thiophenol, which has been attributed to surface sulfur vacancies of CdS, also decreases rapidly after the particle formation. This observation suggests that the surface sulfur vacancies of CdS play an important role in the surface modification by thiols. In the redispersion process of CdS ultrafine particles, the added thiophenol molecules are considered to have two functions: destabilizing the reverse micelles and binding to the surface of the particles ejected from the micelles owing to destabilization. Solvent molecules with both ligand parts and hydrophobic groups are favorable for redispersing the particles covered with thiophenol.

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Automatic fuzzy modeling was studied for Ginjo sake brewing process using a fuzzy neural network (FNN). From the analysis of data for 25 Ginjo sake brewings, the control period was separated into 4 regions. We constructed 4 FNN models for fuzzy control in each control region. Acquired models could estimate the set temperature precisely, and acquired rules coincided well with the experience of Toji. The suitability of acquired models was confirmed by the simulation proposed by us.

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Heat transfer characteristics were investigated in an 80-mm ID jetting fluidized bed with a conical distributor and center nozzle using 0.262-mm alumina particles as the bed material. The temperature profiles at different nozzle diameters, different nozzle gas velocities and temperatures were measured by means of very thin thermocouples. Analysis of experimental data suggests that the axial temperature profiles mainly depend on the nozzle gas momentum. The axial temperature dissipation rate is related to Froude number and the nozzle number. Transverse temperature profiles can be represented by an empirical correlation including the nozzle number and the ratio of radius to nozzle diameter. The thermal penetration height and the thermal boundary were also discussed.

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In order to understand the operating feasibility of the ideal heat integrated distillation column (HIDiC), its control systems are studied in both time and frequency domains with respect to three operating conditions (i.e., feed thermal condition, q < 0.5, q = 0.5 and q > 0.5). It was found that the ideal HIDiC could be operated quite smoothly under all these operating conditions. However, the strongest interaction between top and bottom control loops is observed at q=0.5, and the system resilience may be degraded when q strays from 0.5 because of the strong gain directionality of the process.
The feed location also strongly affects the dynamic performance of the ideal HIDiC. Placing feed in the middle of the process could intensify the interaction between the top and bottom control loops. Therefore, the determination of both feed thermal condition and feed location should be based on a careful compromise between steady state energy saving and dynamic resiliency of the system.

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The μVT-NEMD method, a combination of the μVT-MC and the boundary-driven non-equilibrium MD, has been applied for simulating permeation of pure- and mixed-gases through membranes with slit-like pores under the assumption of local adsorption equilibrium with the feed gas at the entrance of the membrane. The model system is a slit-like pore of graphite plane for the membrane and the methane and the ethane for permeating gases. To reach the stationary state in a simulation run, 50,000–60,000 time steps computation and 500–2,000 molecules in a cell are required for obtaining better statistics in the NEMD. Computer graphics animations clearly show that molecules having entered the pore gather together in monolayers on the surface to form downstream surface flow. Under a constant feed pressure condition, the mass fluxes of gases decrease significantly with increasing temperature because of the decrease in pore density in adsorption equilibrium with a feed gas. In the case of binary mixture permeation, enhanced selectivity of more adsorptive substance (ethane) was observed with an decrease in temperature, the reason for which is the significant decrease in pore density of methane, a weaker adsorptive, due to the competitive adsorption of ethane.

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The problem of the interaction between viscous heating, heat transfer and flow in Couette rheometers is investigated. Series solutions, up to 4th order in the Brinkman number (Br), are developed for planar Couette flows of materials whose viscosity and thermal conductivity can be expressed as polynomial functions of temperature with arbitrary coefficients. The derived solutions are validated by extensive comparison to existing closed-form results and to numerical solutions and are found to be highly accurate for a practical range of (Br). The presented solutions provide valuable insight into the functionality of the relevant dependencies, something that is lost in purely numerical solutions. Based on these results, the distribution of velocity, shear rate and temperature, as well as their sensitivity on material and process parameters are investigated. Finally, corrections for viscosity measurements in Couette viscometers, which account for viscous heating and temperature-dependent material properties, are derived.

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Photocatalytic oxidation of cyclohexane forming the organic phase of reverse micellar systems on in situ prepared TiO₂ ultrafine particles has been investigated. The cyclohexane was photo-oxidized on the TiO₂ ultrarine particles to form cyclohexanone and cyclohexanol under air-saturated conditions. In the absence of O₂, H₂ was generated via reduction of water in the micellar waterpools. CO was also generated in the absence of O₂ probably via a photocatalytic side reaction of 1-butanol which was added as a solvent of the precursor of TiO₂ (titanium tetrabutoxide: TTB) to prepare the particles, 1-butoxyl groups of TTB or 1-butanol formed via hydrolysis of TTB. The molar ratio of water to TTB, W_t (=[H₂O]/[TTB]) was a major factor in controlling the photocatalytic reaction behavior of the system. When the irradiation was carried out under air-saturated conditions for 18 h, the consumption rate of O₂ increased monotonously as the value of the parameter W_t decreased, while the quantities of cyclohexanone and cyclohexanol formed decreased at W_t < 10. This can be attributed to a side reaction of 1-butoxyl groups of TTB molecules which is oxidized more easily than cyclohexane. This reaction becomes prominent in the extremely low W_t range owing to incomplete hydrolysis of TTB molecules.

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In order to simplify the complex coal ignition process, a microgravity condition (10^–3g), in which natural convection is negligible, has been employed to observe ignition of single coal particles. The particle was heated and ignited by radiation from spot heaters. Three coals with different volatile matter contents were employed, having particle sizes in a range of 0.8 mm to 1.2 mm.
As expected, under microgravity, a nearly spherical volatile cloud was found to form around the particle. Results clearly show that regardless of the particle size, the ignition is preceded by homogeneous gas-phase volatile ignition, followed by heterogeneous solid-phase char ignition after burn-out of the volatiles. The heterogeneous ignition temperature and time were higher and longer, respectively, under microgravity than under normal gravity condition. The homogeneous ignition also took place at a higher particle temperature under microgravity than under normal gravity. Further, the temperature for heterogeneous ignition increased with the absolute amount of volatiles contained in a coal particle, whereas the particle temperature for the homogeneous ignition decreased.

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The effect of progressive waves on a liquid surface upon gas absorption in unsteady state was investigated theoretically. The convective-diffusion equation for mass transfer under wavy flow was solved on the basis of a boundary layer approximation. An analytical solution for the dimensionless average mass transfer coefficient was obtained as a function of the dimensionless contact time of gas and liquid τ and the wave velocity ratio U_c, which was defined by the ratio of wave velocity to the amplitude of surface velocity fluctuation. The solution is independent of U_c, and corresponds to that based on Higbie’s penetration theory for short contact time of gas and liquid. For long contact time of gas and liquid, it includes as special cases the analytical solution based on an eddy-cell model proposed by Theofanous et al. (1976) as well as an asymptotic solution in the limit of τ → ∞ obtained by Ruckenstein (1968).

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