Treatment of radioactive waste phenol with Fenton's oxidation

A new procedure was developed for the waste treatment of radioactive phenol on a laboratory scale. Waste phenol was dissolved in water (2% as phenol), and ferrous ion (10 mg/l as Fe2+) was added. Hydrogen peroxide (6% as H2O2) was added separately in three steps, 20, 30, and 50% of the volume, in order to avoid rapid reaction. The solution was heated at 80-90 degrees C for several hours in a beaker covered with a watch glass till the color of the solution changes from red purple to pale yellow. Then, the solution was neutralized with sodium hydroxide and heated for 1 h to decompose excess hydrogen peroxide. When the procedure is carried out with four 2 l beakers on a hot plate, 100 ml of phenol (1,200 ml of the aqueous solution saturated with phenol) can be oxidized simultaneously.     

Highly Blood Compatible Titania Gel

We examined blood compatibility of titania gels prepared through a sol-gel processing or yielded on titanium substrates by treating with hydrogen peroxide or simple heating. The blood compatibility was evaluated in terms of blood clotting time and correlated to the crystalline phases, roughness, specific surface area, and wettability. The sol-gel derived titania gel heated above 200°C had good blood compatibility. Ti substrate treated with hydrogen peroxide and subsequently heated at 550°C showed the best blood compatibility among the Ti substrates with or without the chemical treatment and heat-treatment. The specimen consisted of rutile and anatase phases, and had hydrophilic surface.     

Determination of99Tc in coastal seawater collected in Fukuoka,Japan

Concentrations of⁹⁹Tc were determined by inductively coupled plasma mass spectrometry (ICP-MS) on coastal seawater in the general environment in Japan. Technetium was enriched on iron hydroxide by repetitive co-precipitation method from a large volume of seawater and separated from impurities by solvent extraction and ion-exchange techniques. The concentrations of⁹⁹Tc were 1.0 to 7.4 Bq1^–1, which was one order of magnitude lower than the level reported on seawater from general environment by beta-ray counting. Concentrations of¹³⁷Cs determined on the same seawater were 3.7 and 3.9 mBq1^–1. The activity ratio of⁹⁹Tc/¹³⁷Cs was calculated to be 2.7×10^–4. This ratio was very close to the value expected for fallout from nuclear tests.     

Preparation of manganese-53

The nuclide⁵³Mn was produced by the following three nuclear reactions,⁵²Cr(d, n)⁵³Mn,⁵¹V(³He n)⁵³Mn and⁵⁰Cr(α, n), (α, p)⁵³Mn. Enriched⁵²Cr and⁵⁰Cr metal targets were prepared on copper plate holder by electrodeposition. The commercially available natural vanadium foil was used for the⁵¹V(³He, n)⁵³Mn reaction. Each target was bombarded in a cyclotron. Manganese was extracted and purified without using carrier from the bombarded targets by anion and cation exchanges and solvent extraction. The isotopic ratio⁵³Mn/⁵⁵Mn was measured by mass spectrometry and the amount of⁵⁵Mn was determined by neutron activation analysis. The activity of⁵³Mn obtained was 7 dpm by 750 millicoulombs in³He bombardment (E³He=20 MeV). The activity due to by-product⁵⁴Mn was about several thousands times higher than that of⁵³Mn in³He and deuteron bombardments, which were produced through⁵¹V(³He, γ)⁵⁴Mn and⁵³Cr(d, n)⁵⁴Mn. In alpha bombardment (E_α=15 MeV), the activity of⁵³Mn produced was 8 dpm by 95 millicoulombs. The activity ratio, dpm⁵⁴Mn/dpm⁵³Mn, was about 3, and this ratio was the best one among the results so far obtained.     

Mössbauer spectroscopic study of gamma-ray irradiated potassium phosphate glasses

A Mössbauer spectroscopic study was performed to investigate the effect of γ-ray irradiation on the formation of non-bridging oxygens in the potassium phosphate glasses denoted by the formula x K₂O · (100 ? x)P₂O₅ · 7 Fe₂O₃ (0 ? x ? 50 mol.%). Mössbauer spectra for these glass samples consisted of two kinds of doublets due to Fe²⁺ and Fe³⁺ ions of octahedral symmetries. Only small changes occurred in the Mössbauer parameters as a result of irradiation at room temperature in a dry nitrogen atmosphere, except for the decrease in the absorption area for the Fe²⁺ ions. The decrease in the absorption area was attributed to the electron transfer from the Fe²⁺ ions to the neighboring oxygens. Thermal annealing experiments for a few non-irradiated glass samples indicated that the decrease in the absorption area was confirmed to be due to γ-rays rather than heating during the irradiation.     

Unexpected chain length dependence on a chiral memory effect of ‘meta-ethynylpyridine’ oligomers

The chain length dependence involving a chiral memory effect of 2,6-pyridylene ethynylene oligomers ‘meta-ethynylpyridines’ was investigated. The meta-ethynylpyridine oligomers associated with octyl β-d-glucopyranoside form a helical complex giving induced CD; the induced chirality could be memorized with the help of Cu(OTf)₂ as an additive. Contrary to our expectations, the study of the length dependence revealed that the 12-meric oligomer showed a more sustainable chiral memory effect than those observed in both of the shorter 6-meric and longer 18-meric oligomers.     

Second-order necessary conditions for domain optimization problems in elastic structures,part 1: Surface traction given as a field

In this paper, domain optimization problems for both linear and nonlinear elastic structures are studied. The first variation and the second variation of the objective function are calculated in terms of the solution, of the first variation of the solution for the primal elastic system, and of the adjoint variables introduced. The adjoint variables obey a (fictitious) linear elastic system in contrast with the nonlinear adjoint systems introduced by Dems and Mróz, and by Dems and Haftka. From these results, the first-order and the second-order necessary conditions that an optimal domain should satisfy are immediately derived.Portions of this paper were presented at the 5th IFAC Symposium on Control of Distributed Parameter Systems, Perpignan, France, 1989. The authors would like to express their sincere thanks to the referees for their critical readings.     

Indomethacin sustained-release suppositories containing sugar ester

We prepared indomethacin (IM) sustained-release suppositories using sugar ester (SE) as an additive. The suppositories were prepared by the fusion method with IM, SE, and Witepsol H-15 (H-15) and their availabilities in vitro and in vivo were evaluated mainly by the drug release test and the absorption test in rabbits, respectively. The softening point of the suppositories increased with increasing SE content. In the release test with the Muranishi method, slow-release profiles were obtained when the SE content was more than 52.5%. The absorption of IM from these suppositories, however, was very little. In the other release test, e.g. immersion method with gauze, all of the suppositories with SE showed slow-release profiles, and the drug release rates clearly depended on the SE content. The drug was released from the suppositories by the following leaching-type mechanism proposed by Higuchi. The suppository with a 30% SE content showed a sustained-plasma level of IM, but the other suppositories did not. It was concluded that an appropriate content of SE (i.e. 30%) in the suppository base was required to obtain sustained-release because it reasonably regulated the infiltration of rectal fluid into the suppository and the mechanical strength of the suppository against disintegration.