Antioxidant effect of the constituents of susabinori (Porphyra yezoensis)

The antioxidant activities of several extracts from Susabinori (Porphyra yezoensis) were measured by the ferric thiocyanate method and the thiobarbituric acid method. The methanol, acetone, ethyl acetate, and hexane extracts, and the chloroform-soluble and water-soluble fractions from the chloroform-methanol extract exhibited higher activities than α-tocopherol. The hot water extract showed little activity. Thin-layer chromatography analysis of the active extracts suggested the existence of several antioxidants. The activity of the chloroform soluble fraction was due to chlorophyll analogs. A strong antioxidant was isolated from the methanol extract, accompanied by several amino acids such as leucine and phenylalanine. This compound was identified as usujilene, a kind of mycosporine-glycine like amino acid.     

Practical inspection system of drill point geometry by using simple measurement jig and image processing

The proper simple inspection system for drill point geometry will support the skillful drill regrinding operation. In this paper, a newly developed system for practical use in machine shops has been described. The measurement method is based on silhouette image processing described in the author’s previous papers. But, for easy and robust inspection, a simple measurement jig was designed and the identification method of the five geometrical parameters describing its complete geometry was modified. Then, the error motion of the jig was tested and a compensation strategy of its error was proposed. The results show that the drill angles such as the outer clearance angle measured by this system are more precise than those measured by a microscope. Moreover, this system can measure the five geometrical parameters of the drill, which cannot be measured by using the microscope.     

Natural convection and radiation heat transfer in a vertical porous layer with a hexagonal honeycomb core (Part 2: heat transfer experiment)

Combined natural convection and radiation heat transfer characteristics in a vertical porous layer with a hexagonal honeycomb core were investigated experimentally. The temperature distributions on the honeycomb core wall and the combined heat transfer rates through the porous layer were measured. The measurements of the heat transfer were accomplished using the guarded hot plate method. The honeycomb core wall was made of paper and large-mesh foamed resins were inserted into the honeycomb enclosures. The measurements were performed by varying the radiation parameters between 0.5 and 0.65, varying the temperature ratios between 0.01 and 0.1, and varying the Darcy-Rayleigh numbers between 5 and 80, and for a fixed aspect ratio H/L = 1. The experimental results for Nusselt numbers agreed well with our available numerical results. © 1999 Scripta Technica, Heat Trans Asian Res, 28(4): 295–306, 1999     

A solution to the unit commitment problem considering LNG fuel constraints

In this paper, an algorithm is proposed for finding a quasi-optimal schedule for the short-term thermal unit commitment problem taking LNG fuel constraints into account. In recent years, LNG fuel has been used increasingly. As a result, LNG fuel constraints should be considered in making a unit commitment schedule. Generally, unit commitment is a nonlinear combinatorial problem including discrete variables. To solve the problem, a two-step algorithm is developed using mathematical programming methods. First a linear programming problem is solved to determine the amount of LNG fuel to be consumed by each LNG unit, then a Lagrangian relaxation approach is used to obtain a unit commitment schedule. This two-step algorithm simplifies the problem and thus has good convergence characteristics. To test the effectiveness of the proposed algorithm, a numerical simulation was carried out on a 46-unit thermal system over a 24-hour period. A result with a dual gap of 0.00546 was obtained. © 1998 Scripta Technica, Electr Eng Jpn, 125(3): 22–30, 1998     

Grafting reaction of living polymer cations with amino groups on chitosan powder

The grafting of polymers having controlled molecular weight and narrow molecular weight distribution onto chitosan powder by the termination of living polymer cation with amino groups on chitosan powder was investigated in heterogeneous system. The amino groups of chitosan powder successfully reacted with living poly(isobutyl vinyl ether) [poly(IBVE)] and poly(2-methyl-2-oxazoline) [poly(MeOZO)] cation with controlled molecular weight and narrow molecular weight distribution to give the corresponding polymer-grafted chitosan powders. The percentage of poly(MeOZO) grafting gradually increased and reached 24.5% after 4 days. The solubility of poly(MeOZO)-grafted chitosan in water increased with an increase in the amount of grafted polymer. It was suggested that grafting reaction of living polymer cation with chitosan powder proceeds from surface amino groups to inner amino groups of the powder with progress of the reaction. The mole number of grafted polymer chain on chitosan powder decreased with an increase in the molecular weight of the living polymer cation because the steric hindrance of functional groups of chitosan powder increased with the increasing molecular weight of living polymer. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1883–1889, 1998     

Measurement and correlation of supercritical CO2 and ionic liquid systems for design of advanced unit operations

Ionicliquids combined with supercritical fluid technology hold great promise as working solvents for developing compact processes. Ionic liquids, which are organic molten salts, typically have extremely low volatility and high functionality, but possess high viscosities, surface tensions and low diffusion coefficients, which can limit their applicability. CO₂, on the other hand, especially in its supercritical state, is a green solvent that can be used advantageously when combined with the ionic liquid to provide viscosity and surface tension reduction and to promote mass transfer. The solubility of CO₂ in the ionic liquid is key to estimating the important physical properties that include partition coefficients, viscosities, densities, interfacial tensions, thermal conductivities and heat capacities needed in contactor design. In this work, we examine a subset of available high pressure pure component ionic liquid PVT data and high pressure CO₂ - ionic liquid solubility data and report new correlations for CO₂-ionic liquid systems with equations of state that have some industrial applications including: (1) general, (2) fuel desulfurization, (3) CO₂ capture, and (4) chiral separation. New measurements of solubility data for the CO₂ and 1-butyl-3-methylimidazolium octyl sulfate, [bmim][OcSO₄] system are reported and correlated. In the correlation of the CO₂ ionic liquid phase behavior, the Peng-Robinson and the Sanchez-Lacombe equations of state were considered and are compared. It is shown that excellent correlation of CO₂ solubility can be obtained with either equation and they share some common characteristics regarding interaction parameters. In the Sanchez-Lacombe equation, parameters that are derived from the supercritical region were found to be important for obtaining good correlation of the CO₂-ionic liquid solubility data.     

Identification of Lactic Acid Bacteria from Algerian Traditional Cheese,El-Klila

The lactic acid bacteria from dried El-Klila, an Algerian traditional cheese were studied, The cheese was also examined for chemical and physical characteristics. The isolated strains from sample K1 belonged to Enterococcus faecalis , Enterococcus faecium , Lactobacillus confusus and Streptococcus sp. Enterococci were the most frequently found. However, the isolates from sample K3 were identified as Pediococcus sp, Pediococcus acidilactici , Lactobacillus sp, Streptococcus sp and Leuconostoc sp. Pediococci were the predominant strains. The samples had high protein content (538·5 g kg⁻¹ for K1 and 549·8 g kg⁻¹ for K3) and considered as extra-hard cheese.     

Studies on regenerated protein fibers. III. Production of regenerated silk fibroin fiber by the self-dialyzing wet spinning method

The spinnable dope containing 20 wt % of silk fibroin dissolved in the MU solvent (e.g., LiBr · H₂O = 40 wt %, and EtOH : H₂O = 100 : 0 in volume) was spun into a coagulant and subsequently drawn, to give the following results.

• 1 Methanol, ethanol, and isopropanol were a predominant coagulant for the dope, and the coagulant containing 10% LiBr · H₂O is best.
• 2 Spinnability depended upon the ratio of nozzle hole length to diameter (L/D) and was improved by increasing L/D from 4 to 10. Coagulativity was not sufficient at the SF concentration of 16%, but improved by raising it up to 20%. Drawability of the spun filaments in water was improved at a temperature above 60°C.
• 3 The drawn fiber showed excellent mechanical properties, especially tensile toughness when as-spun fiber was drawn in water at 61°C. An X-ray diffraction diagram of the drawn fibers indicated their crystalline axes were partially oriented along the fiber axis. © 1996 John Wiley & Sons, Inc.

     

Wave venation in downward gas-liquid two-phase flow (part II,cluster analysis for huge waves and disturbance waves and characteristics of those waves)

Wave velocities and wave widths were determined using wave-vein analysis for a wide range of air and water flow rates. Cluster analysis by a K-mean algorithm was applied to the discrimination between huge and disturbance waves for the present experimental conditions. Individual waves discriminated by cluster analysis reasonably correspond to those recognized from the relation between wave velocity and wave width. Appearance flow conditions for liquid slug, huge and disturbance waves were clarified. The characteristics of wave velocity, wave width, and maximum liquid holdup for huge and disturbance waves are discussed. Comparison between liquid slug, huge wave and disturbance wave flow parameters reveals that there exist distinct differences in wave width of these waves. © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25 (8): 511–521, 1996     

Purification and Properties of the Raw Starch Digesting Amylase from Penicillium brunneum No. 24

Raw sago starch digesting amylase was obtained from Penicillium brunneum No. 24. The crude enzyme from this strain contains carboxymethylcellulase (CMC-ase), avicelase, α-amylase and α-glucosidase. Affinity chromatography (α-cyclodextrin-Sepharose 6B) of the enzyme after ammonium sulfate fractionation, Toyopearl HW-55F gel filtration, DEAE-Sephadex A-50 and DEAE-cellulose chromatographies fractionation steps, resulted in a homogeneous glucoamylase. SDS-polyacrylamide gel electrophoresis of purified enzyme showed a single band, and a molecular weight of 80,000 for the native glucoamylase from Penicillium brunneum No. 24 was observed. After modification of the native glucoamylase with subtilisin, the molecular weight was reduced to 76,000. It lost the ability to digest and adsorb onto raw starches. However, its ability to digest gelatinized starches was preserved.