Surface Waves on Superfluid <Superscript>4</Superscript>He Under Reduced Gravity

Superfluid ⁴He was produced on a small jet plane for the first time using a small GM-refrigerator to condense the liquid and a scroll pump to get the superfluid by evaporation. The surface wave on superfluid under 0.5g _E, 0.1g _E and 0.05g _E, together with 2g _E and 1g _E, was successfully examined by an optical method utilizing parabolic flight. Here, g _E is the gravitational constant on the ground. Assuming that only the fundamental mode was excited as determined by the sample cell width, the resonance peak in the frequency domain was well reproduced by the gravity wave with corresponding gravity constant.     

Analysis of terminal voltage waveform of AC exciting synchronous generators

Recently, adjustable speed hydroelectric power systems have been developed. In those power systems, ac exciting synchronous generators are used instead of the ordinary salient-pole-type synchronous machines. However, some higher harmonic sequences are included in the distribution of air-gap magnetic flux density and in the terminal voltage waveform of the ac exciting synchronous machines because these machines have open winding slots. To develop better machines without terminal voltage waveform distortions, an evaluation method of the terminal voltage harmonics has been needed. This paper describes the mechanism of higher harmonics generation qualitatively and proposes an analytical method of no-load terminal voltage waveforms on the basis of two-dimensional magnetic field analysis considering movement of the rotor for quantitative higher harmonics analysis. The analytical results of higher harmonics show good agreement with the experimental ones.     

Long life sealed nickel-zinc cell using a new separator

Because of internal shorting due to zinc (Zn) dendrite formation at the Zn electrode, nickel-zinc (NiZn) secondary cell cycle life is somewhat less than the NiCd cell cycle life. To solve this problem, a new kind of separator was developed which consisted of nylon non-woven cloth coated with poly(vinyl alcohol) (PVA) containing boric acid. This separator has a high ionic conductivity, but is resistant to zincate ion penetration. A large number of additives, effective for Zn dendrite suppression, was also tested. From them, bismuth oxide (Bi₂O₃) was selected and added, together with calcium hydroxide (Ca(OH)₂), to the Zn electrode. A charging method, applying an intermittent anodic pulse, was found to be effective to reduce the Zn electrode shape change and prolong the cycle life of this cell. By using these materials and investigating a cell construction containing an electrolytic solution and hydrogen gas absorber, sizes AA, C, and D sealed NiZn cells were developed whose charging and discharging cycle life achieved over 500 cycles, for a size C cell.     

Preparation of Nd(III) carbonate by precipitation stripping of Nd(III)-loaded VA10

The preparation of fine particles of Nd(III) carbonate from kerosene solution, from which Nd(III) was extracted with versatic acid 10 (VA10) by a precipitation stripping technique using an aqueous NH₃-(NH₄)₂CO₃ solution as stripping medium, was studied. In preliminary experiments, we were unable to recover simple Nd(III) carbonate from Nd(III)-loaded VA10 by CO₂ gas bubbling, when water, (NH₄)₂CO₃, NH₄HCO₃, NaHCO₃, or NA₂CO₃ solution saturated with CO₂ was used as the stripping solution. To obtain simple Nd(III) carbonate, it is necessary to use more than the stoichiometric amount of NH₃ compared to VA10 and about 10 times as much (NH₄)₂CO₃ as Nd(III). The solution mixture of NH₃-(NH₄)₂)CO₃ acts as a pH buffer, an adductor for VA10, and a CO ₃ ²⁻ ion source. Although it was concluded that the precipitates are Nd₂(CO₃)₃·xH₂O (x⊧4), their X-ray pattern does not coincide with that quoted by JCPDS. By heating these precipitates, cubic Nd₂O₃ was obtained at 823 K, while, at 973 K, hexagonal Nd₂O₃ was formed. Since the stripping solution consisting of NH₃-(NH₄)₂CO₃ was highly alkaline, VA10 was also stripped in the aqueous phase. To use a closed-circuit system for the precipitation stripping of Nd(III) carbonate from Nd(III)-loaded VA10, it is important to regenerate VA10 in the organic phase. For this purpose, evaporation of NH₃ by air bubbling was studied. By bubbling air into a stripping solution warmed at 333 K, almost all the VA10 can be transferred to the organic phase.     

Spore fatty acid composition in Bacillus natto, a food microorganism

The levels of fatty acids and their distribution were determined in spores from twenty-five strains of Bacillus natto isolated from a fermented soybean food, natto, or subcultured from the culture collection. The major fatty acid components of spores, consisting of about 80 to 90% of the total, were anteiso-C₁₅, anteiso-C₁₇, iso-C₁₅ and iso-C₁₇; the other fatty acids, at a level of 10 to 20% of the total, were iso-C₁₄, iso-C₁₆, n-C₁₄, n-C₁₆ and n-C₁₈. The amount of fatty acid in spores was highest with anteiso-C₁₅, followed in order by iso-C₁₅. In addition to the nine fatty acids, some of the strains produced six extra fatty acids, three branched (anteiso-C₁₃, iso-C₁₂ and iso-C₁₃) and three normal (n-C₁₂, n-C₁₅ and n-C₁₇).