Flow Induced Acoustic Resonance in In-line Tube Banks

In the present paper the attention is focused on the relation between vortex shedding phenomena andacoustic resonance which occurred in the two-dimensional model of boiler.There were tube bankswith in-line arrangement for small tube pitch ratio.We measured the sound pressure level,the phasedelay of acoustic pressures,the spectrum of velocity fluctuation and the gap velocity.As a result, wefound two peak frequencies of sound pressure level with different Strouhal numbers S_t,mainly about0.26 and 0.52.The noise of S_t=0.26 was the resonance of transverse mode and S_t=0.52 waslongitudinal mode.The vortex shedding of S_t=0.15 was generated inside the tube banks withoutacoustic resonance. As gap velocity increased, we observed that the peak level of spectrum was weakand broad-banded. The onset velocity of the acoustic resonance of longitudinal mode was lower thanthat of transverse mode.     

Microbeam line with 1.5 MeV helium ions and protons at Osaka

A microprobe for Rutherford backscattering (RBS) and particle-induced X-ray emission (PIXE) measurements has been realized by focusing 1.5 MeV helium-ion or proton beams with a demagnification system consisting of piezo-driven objective slits and a magnetic quadrupole doublet. Minimum beam spot sizes of 1.3 × 2.2 μm² for helium ions and 2.2 × 4.0 μm² for protons have been achieved. The factors which may limit the minimum spot size are discussed using a Monte Carlo simulation procedure. Rutherford backscattering image mapping of 3-dimensional structures is demonstrated.     

On the combination of sulphite with food ingredients (aldehydes, ketones and sugars). II.

Summary Three kinds of combined sulphites (bisulphite adducts of acetaldehyde, pyruvic acid and D-mannose), different in combination strength, were prepared to provide a model system for comparative studies on the accuracy of several determination methods for combined sulphites. The purity of the combined sulphites, obtained either as crystals or amorphous powder, was shown to be not less than 99%.Five methods, formerly applied on the determination of residual sulphites in foods, were subjected to the determination of these combined sulphites. A modified Monier-Williams method, iodimetry and distillation-colorimetry were effective for the determination of combined sulphite, whilst a microdiffusion method and direct colorimetry (by use of mercuric chloride) were shown to be inadequate for the determination of combined sulphite.Three combined sulphites were shown to be produced by the reaction between free sulphite and acetaldehyde, pyruvic acid or D-mannose at room temperature within a short time in the weak acid to slightly alkaline pH range. About 50% of combined sulphite were produced by the reaction of equimolar amounts of sodium bisulphite and acetaldehyde or pyruvic acid.

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Über die Bindung des Sulfits an Lebensmittelbestandteilen (Aldehyde, Ketone und Zucker). II.

Zusammenfassung Es wird die Darstellung der Bisulfit-Anlagerungsverbindungen von Acetaldehyd, Brenztraubensäure undd-Mannose beschrieben. Die Reinheit der gen. Verbindungen beträgt 99%.fünfAn Hand dieser Verbindungen wird überprüft, welche von fünf Standardmethoden zur Sulfitbestimmung in Lebensmitteln für die Bestimmung des gebundenen Sulfits geeignet ist. Hierbei ergeben die abgeänderte Monier-Williams-Methode, die Jodometrie und die Wasserdampfdestillation/Colorimetrie befriedigende Ergebnisse, während die Mikrodiffusion und die direkte Colorimetrie ungeeignet erscheinen.Die gen. Anlagerungsverbindungen bilden sich bei Zimmertemperatur im schwach sauren bis schwach alkalischen Milieu innerhalb kurzer Zeit. In einer äquimolaren Lösung aus Acetaldehyd bzw. Brenztraubensäure und Natriumhydrogensulfit liegt nach kurzer Zeit 50% des Sulfits als Anlagerungsverbindung vor.

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Studies on the Analyses of Sulphites in Food (II)     

Comparative determination of free and combined sulphites in foods by the modified rankine method and flame photometric detection gas chromatography. V.

Summary Application of the modified Rankine (MR), GLC and present official Monier-Williams methods to the determination of sulphites in a variety of foods was attempted. Generally, sulphite contents determined by these three methods were in good agreement although the values obtained by the modified Monier-Wiliams method were slightly higher than by the other two. A marked interfering effect of other sulphur compounds was observed in the case of determinations by the Monier-Williams method. On the other hand, the determined sulphite values by the MR and GLC methods were independent of the coexisting sulphur compounds. The ratios of free or combined sulphites to total sulphites were compared among the two methods, and in most foods tested the rations of combined to total sulphites were not less than 65%. We conclude that both the MR and GLC methods are valid for the separate determination of free and combined sulphites in most foods, and these two methods will be preferred for routine analysis because of their simplicity and speed.

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Vergleichende Bestimmungen der freien und gebundenen Sulphite in Lebensmitteln mittels der modifizierten Rankinemethode und der Gaschromatographie mit Flammenphotometer-Detektor. V.

Zusammenfassung Es wurde eine vergleichende Sulfitbestimmung in verschiedenen Lebensmitteln mit Hilfe der modifizierten Rankinemethode (MR), der Gaschromatographie und der Monier-Williams-Methode durchgeführt. Die Ergebnisse stimmen gut überein, wobei die Monier-Williams-Methode geringfügig höhere Werte erbrachte. Diese Methode wird durch schwefelhaltige Lebensmittelinhaltsstoffe empfindlich gestört.Des weiteren wurde in verschiedenen Lebensmitteln die Relation von freiem zu gebundenem Sulfit ermittelt. Dabei stellte sich heraus, daß in den meisten Lebensmitteln 65% des Sulfits in gebundener Form vorliegen. Sowohl MR-Methode als auch Gaschromatographie erlauben eine getrennte Bestimmung von freiem und gebundenem Sulfit. Da beide Methoden einfach und schnell durchzuführen sind, eignen sie sich für die Routinebestimmung.

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Studies on the Analyses of Sulphites in Foods (V).     

Four Promising Multimedia Databases and Their Embodiments

Multimedia database systems have become more and more important as the tool to extract and generate additional values from multimedia Contents. In this paper, four multimedia database systems are proposed from the view point of promising contents sources; the Network multimedia databases, the Stream MM database systems, the Library MM database systems, and the Real world MM database systems. Important problems to be solved, i.e., what to do, are also discussed for each databases. Three concrete multimedia systems by authors' research group, are then introduced and discussed as the embodiments of these multimedia systems; (1) the open Global Image Retrieval and Linking System, GIRLS, for mediation WWW data pace as the network MM database systems, (2) the flexible multimedia database platform GOLS, and (3) the higher level authoring system for the Stream MM environments.     

Morphological Study of Cavity and Worthington Jet Formations for Newtonian and Non-Newtonian Liquids

In this article a morphological study of the cavity formation and the liquid column formation of the Worthington jet with lapse of time for the Newtonian liquids of water and glycerine wt 70% solution and for non-Newtonian liquids of acrylic copolymer solution of ACA-wt1%, ACA-wt2%, and ACA-wt3% by a droplet falling to the free surface of the target liquid in the cylindrical container from a height of H = 100, 200, 300, 400, and 500 mm is described. The calculated results by the energy equation for the maximum cavity radius Rmax/d and for the morphological size D · h/d² of the Worthington jet are in agreement with the experimental results. In order to take photographs of the cavity formation and the Worthington jet formation with lapse of time, a CCD camera was used. The falling droplet and the target liquid are the same material. Here d is the mean diameter of the droplet and D and h are the mean diameter and maximum height of the liquid column of the Worthington jet.     

Prediction of thermal coagulation by AC inductive heating of Mg1-xCaxFe2O4 ferrite powder

The purpose of this study is to investigate the thermal characteristics of Mg_1−XCa_XFe₂O₄ ferrite powder by applying AC magnetic field and to predict the effect of thermal coagulation in vivo. We found that heating characteristics of the ferrite powder became greater as the frequency through the 400 kHz to 700 kHz range. The highest heat generation was attained using 7–15 nm ferrite powder. We also carried out a heat transfer simulation in which we were able to demonstrate that this material has sufficient heat generating characteristics to thermally coagulate a tumor cell and that it is possible to predict the range of the coagulation from the present simulation.     

Enhancement of the thermoelectric power factor in Ag/Bi-Te/Ag composite devices

The resultant thermoelectric properties of the p- and n-type Ag/Bi-Te/Ag composite devices welded with pure Bi were measured at 298 K as a function of relative thickness of x, where x is the ratio of thickness of Bi-Te compound to the interval between two thermocouples and the chemical compositions of the p- and n-type Bi-Te compounds used here are (Bi_0.25Sb_0.75)₂Te₃ and Bi₂(Te_0.94Se_0.06)₃, respectively. Consequently, the electrical resistivities ρ of the p- and n-type Ag/Bi-Te/Ag devices increased linearly with an increase of x, while the Seebeck coefficients α were enhanced significantly in the range from x = 0.03 to 0.10, so that their observed P values have a large local maximum at x = 0.06. The x-dependence of P values was found to be explained roughly with the simple model proposed here when some reduction in the thermal conductivity κ of Ag and Bi was taken into the calculation. The maximum P of the p- and n-type Ag/Bi-Te/Ag devices reached extremely large values of 27.8 and 88.3 mW/K²m, which are higher than 25.7 mW/K²m obtained for the previous n-type Ni/Bi/Cu device.