For the purpose of cellobiose production from cellulose, removal of β-glucosidase from cellulase was studied. This purpose can be achieved by an affinity precipitation technique using a reversibly soluble polymer depending on PH. The polymer was hydroxypropyl methyl cellulose acetate succinate (AS-LF). β-glucosidase did not conjugate AS-LF, while the rest of the components did. The conjugated components gave high cellobiohydrolase and endo-β-1,4-glucanase activities. These components were detached by centrifuging with 1.0 M acetate buffer, pH 3.5 from AS-LF, but it was impossible to detach these components by 0.1 M acetate buffer, pH 5.0. Hydrolysis of three kinds (KC-flock, Pulp-flock and Avicel) of cellulose powders with these detached components from AS-LF was carried out. The soluble reducing sugar contained glucose and cellobiose, and the cellobiose content in the product was over 50 mol% for each substrate. Moreover, when the hydrolysis was carried out using the solubilized AS-LF conjugating the components of high cellobiohydrolase and endo-β-1,4-glucanase activities, continuous cellobiose production could be performed by means of repeated affinity precipitation as follows. The reaction products from the insolubilized AS-LF and the residual substrate were separated by adjusting the PH of the reaction medium at an appropriate interval, and the precipitates were dissolved again to continue the reaction.
The separation of Eu from Sm and Gd by combination of electrochemical reduction and solvent extraction was investigated. A two-compartment cell separated by a cation exchange membrane and equipped with a titanium plate electrode was used. Trivalent Eu was reduced to the divalent form by electroreduction in (NH4) 2SO4 aqueous solution containing SmCl3, EuCl3 and GdCl3 to form EuSO4 precipitate selectively. The purity of Eu in the precipitate was more than 97%. The electro-reductive stripping of Eu was studied by using a two-compartment electrochemical cell. In two-phase systems consisting of metal-loaded di-5-methyl-2-(1-methylneohexyl)neodecanoyl phosphoric acid (DP-18) or bis(2-ethylbexyl)phosphoric acid (D2EHPA) diluted with xylene and (NH4) 2SO4 aqueous solutions, Eu3+ was reduced at the aqueous phase/electrode interface and EuSO4 precipitated selectively in the aqueous phase. The recovery of Eu as EuSO4 from an organic solution containing equal amounts of the three elements was dependent on the aqueous-phase pH and attained up to 83.2% at pH 1.8 in the DP-18 system. The purity of Eu in the precipitate was more than 95%.
The vapor-liquid equilibria with chemical reaction equilibrium of a quaternary system, acetic acid-ethanol-water-ethyl acetate, were measured in an equilibrium still by the static method. The experimental data were correlated by using the modified UNIQUAC equation to satisfy the chemical equilibrium condition as well as the vapor-liquid equilibrium condition. The UNIQUAC binary parameters were obtained from experimental vapor-liquid equilibrium data with chemical reaction equilibrium in the liquid phase of the quaternary system and existing equilibrium data for the six binary and the two ternary systems. The correlations of both the vapor-liquid equilibrium and the chemical reaction equilibrium in the liquid phase were found to be in good agreement with the experimental data.
Instead of using Darcy’s law, we have adopted Ergun’s Equation, dP/dz = K1Ua + K2Ua2, for the force balance model proposed by Mamuro et al. The equations we derived give the general expression of the longitudinal distributions of fluid velocity and pressure in the annulus, and of the maximum ratio of spouting to fluidizing pressure drop. Calculated results show that there is no remarkable difference in the longitudinal distribution of fluid velocity in the annulus, even if the form of Ergun’s equation changes between its two extremes, –dP/dz = K1Ua and –dP/dz = K2Ua2. On the other hand, the longitudinal pressure distribution and the maximum ratio of spouting to fluidizing pressure drop change significantly. The maximum ratio of spouting to fluidizing pressure drop changes in the range from 0.75 to 0.63.
The hydraulic permeation properties of water through heat-treated polyvinyl alcohol (PVA) membrane were investigated. It was found that the flux of water is a highly nonlinear function of the applied pressure. The relation vw,o = vw,1(l – bΔP) was proposed for obtaining a modified solution diffusion equation which can describe the hydraulic permeation of water through heat-treated PVA membrane from experimental flux data. The modified solution diffusion equation was successfully tested for validity by three techniques. The data and modified solution diffusion equation appear to be in excellent agreement. The activation energy for water permeability is independent of the applied pressure on the heat-treated PVA membrane.
The present purpose is to study the influence of far-infrared irradiation on pasteurization of Escherichia coli and Staphylococcus aureus on or within a model for wet-solid food. Agar medium was used as the food model. By determining the thermal resistances of the test bacteria, the pasteurization effect of far-infrared irradiation (radiative heating) was compared with that of hot-air heating (a conventional method) from the viewpoint of thermal death kinetics. It was found experimentally that far-infrared irradiation is more effective than hot-air heating for the test bacteria on the agar-plate. Moreover, it is suggested that the surface temperature of the pasteurization sample irradiated by far-infrared radiation is higher than that measured by the thermocouples.
In the previous paper, the authors proposed a simple model which describes elutriations of one particle species from bubbling fluidized beds made up of one- or two-component particles, by consideration of the obstructive effect due to suspended particles in the freeboard. In this report the proposed model was applied to the elutriations of more than one species of particles from multicomponent fluidized beds consisting of glass beads, FCC particles and iron powders. The applicability of the model to such systems and the obtained best-fit values of the model parameters were examined thoroughly. It was proved that the model also describes well the elutriation of more than one species of particles. The virtual elutriation rate constant in the proposed model, which is one of the model parameters and means the imaginary elutriation rate constant without the obstructive effect, agreed well with the conventional elutriation rate constant predicted by the correlation proposed by Wen and Hashinger. The other parameter kp was in proportion to the reciprocal of the slip velocity.
The effect of vibration on mass transfer was studied for two cases, one being local and overall mass transfers from a single cylinder and the other being those from tube banks, i.e., staggered and in-line tube banks. As for a vibrating single cylinder, the local Sherwood numbers showed the highest value at the positions of θ = 0 and 180, and the minimum value at θ = 90. This was because the inner circulation flows near the vibrating cylinder affected the local mass transfer at high Schmidt number. The local mass transfer rates for the tube banks were greater than those for the single cylinder at any position and any pitch. Correlation equations of the overall mass transfer for the tube banks were proposed with the Reynolds number and a voidage function used in a packed bed.
The recycling free-How electrophoretic separation of amino acids has been investigated experimentally and theoretically. An electrophoretic apparatus with dimensions of 200 × 120 × 1 mm and 20 fraction collectors has been constructed. Experiments in separation of p-amino benzoic acid and histidine have been performed to test The behavior of the apparatus in the isoelectric focusing mode. The experimental results have shown that amino acids can be effectively separated under some acceptable operating conditions, Simultaneously, a mathematical model under an assumption of the quasi-steady state has been presented and solved numerically. The theoretical analysis enables us to describe the concentration change of each species in the fraction collectors quantitatively and to select reasonable operating conditions.
For the pancake CVD reactor, a mathematical model for global analysis of beat transfer in the reactor was developed, and the effects of the geometry and location of the RF coil and the frequency of the RF current on the temperature distributions in the reactor, especially on the susceptor, were investigated. It is found that the heat generation rate in the susceptor is strongly affected by the location of the RF coil and the current frequency, and that the temperature variation on the susceptor is large with the plane RF coil. Also, by modifying the geometry of the RF coil, the temperature distributions on the susceptor can be easily improved.
This paper proposes a multi-model control method based on fuzzy set theory and its application. Fuzzy set theory is provided for unification of the multi-step response models built in various operating points. A control strategy for regulatory control and tracking control can be realized by using these models and the design algorithm of a PID controller. This method was applied to stabilize the distillate component in an ethanol/water distillation system. It was experimentally confirmed that multi-model control using fuzzy rules was an effective method for developing a practical control system for the distillation system.
Escherichia coli JM105 harboring an expression plasmid which bears the xylose isomerase gene controlled by tac promoter was cultivated under different conditions in order to find an optimal fermentation condition. By shake-flask cultures it was found that low concentration of organic nitrogen sources such as yeast extract or casamino acids was essential for efficient production of xylose isomerase. By fed-batch culture in a jar-fermentor, we obtained very high cell concentration. Glucose did not hamper gene expression as much as glycerol. Excess addition of yeast extract lowered the specific activity of the gene product. Although the specific activity of the enzyme in high-concentration culture was a half that in batch culture, the amount of enzyme produced by unit volume in a representative high-concentration culture was more than 33-fold that by batch culture.
The separation of amino acids from aqueous solutions was performed using sulforrated polysulfone membrane at various pH values under a pressure gradient. The volume flux and the solute flux were measured under conditions where amino acids dissociated. With increasing concentration of amino acid in the feed solution, the solute flux increased and the volume flux decreased. The effective charge density of the membrane was determined from measurement of the membrane potential. By applying the proposed friction model incorporated with the effective charge density and the degree of dissociation of amino acid, the basic equations of volume flux and amino acid ion fluxes were derived. The effects of the concentration of amino acid and pH in the feed solution on the volume flux and the solute flux were analyzed on the basis of these equations, and the friction parameters were evaluated.
Polyacrylonitrile (PAN) MF membranes were prepared by phase inversion from dimethyl sulfoxide solvent into water, using polyester nonwoven fabrics as the support material. Three kinds of methods for coating nonwoven fabrics with a PAN dope were tested: casting, saturation and ultrasonic-saturation. The ultrasonic-saturation membrane was found to be excellent in structural stability and reproducibility, and the particle retention of the membrane could be controlled by the PAN-dope concentration and the gelation temperature. The laboratory-made PAIN membrane was almost symmetric, with a pure-water flux higher than that of commercial MF membranes when the pore size was less than 0.1 μm.
Biocatalyst immobilization carrier was coated with calcium alginate gel by a two-step preparation procedure for prevention of leakage of the biocatalyst from the carrier. A uniform gel coating film could be formed around not only calcium alginate get beads but also chitosan beads. The thickness of calcium alginate gel coating increased with decreasing sodium alginate concentration and stirring rate, and with increasing concentration of calcium ion and diameter of the core bead. The volume of gel coating film was shown to be proportional to the mass of calcium ion initially contained in the core bead. It was also found that the thickness of gel coating film could be controlled by adjusting the calcium concentration in the core bead.
Computer-aided methods are applied to the development of an estimation method for aqueous solubilities of organic compounds. Multivariate linear regression models in terms of various molecular descriptors, in particular molecular size and polar descriptors, are examined. The proposed model has been tested by predicting the aqueous solubilities of about 500 organic compounds having diverse structures and functionalities. For the majority of compounds studied, good agreement between observed and estimated solubility is confirmed. This study gives new insight into the effect of atomic charges on the solubility of organic compounds in water.
Etch rates of (100) silicon wafers in KOH solutions were measured and correlated in a wide range of KOH concentration and solution temperature where etching proceeded anisotropically. The operating conditions to provide surfaces free from micropyramids (MPs) were empirically determined for the case of preparing silicon thin diaphragms from 4-in. wafers for use as pressure sensors. The relations between operating conditions and the presence of NIPS were shown diagrammatically in terms of KOH concentrations and temperatures, such as the findings that etched surfaces were smooth and free from MPs primarily at higher KOH concentrations and secondarily at higher temperatures. MP formation was assumed to be caused by silicon oxide precipitates existing in the wafers which dissolved in KOH solutions at rates much lower than the etch rates of silicon crystals under the operating conditions examined. In addition to these precipitates some silicon complexes and/or contaminants in the KOH solutions were also suggested to participate in NIP formation.
This study examined the effects of an additive, Bismarck Brown dye, on the crystallization kinetics of potassium alum crystals in a well-mixed continuous crystallizer. In the data analysis, size-dependent growth kinetics was assumed. The addition of Bismarck Brown dye depressed crystal growth and nucleation rates. The supersaturation of solution at steady state in the crystallizer increased as the Bismarck Brown concentration increased under the constraint of constant retention time and magma density. In this case the growth rate was enhanced but the nucleation rate was reduced. The predicted kinetic behaviors influenced by the addition of Bismarck Brown dye were in good agreement with the experimental results.