Fan noise reduction of household refrigerator

The authors describe the method of reducing the fan noise, especially the impeller noise, of a household refrigerator. The fan in the refrigerator tested is a propeller fan, and the fan unit consists of an impeller, which has four blades, a rear board, which covers the evaporator, and a front board, which has a number of openings. The flow through the openings freezes food in the freezer. By measuring the internal flow with a laser Doppler velocimeter, it was made clear that the flow through the impeller was not symmetrical to the axis. The unsymmetrical flow seems to be caused by the restrictions of flow passages, and it might produce the impeller noise. The search for the sound source by the sound intensity method indicated that the noise was radiated through the openings of the front board. Guiders were installed on the rear board in the fan unit to guide the flow away from the openings. As a result, the impeller noise was reduced, whereas the flow was kept almost the same     

Purification and some properties of a chitinase from Xanthomonas sp. strain AK

Chitinase B (ChiB) was purified from the culture supernatant of Xanthomonas sp. strain AK by Phenyl-Toyopearl 650M and DEAE-Toyopearl 650M column chromatographies. The purified enzyme preparation gave a single band on SDS-polyacrylamide gel electrophoresis and the molecular weight of ChiB was estimated to be 48,000. The enzyme was optimally active at pH 6.0 and 60 degrees C. N-Terminal amino acid sequence analysis suggested that ChiB is a member of glycosyl hydrolase family 18 and that it is genetically different from ChiA recently reported (Sakka et al., J. Ferment. Bioeng., 86, 527-533, 1998). Immunological analysis suggested that ChiB was the major chitinase species in the culture supernatant of Xanthomonas sp. strain AK and that production of the enzyme was induced by the presence of chitin.     

Recent development of nucleic acid drug

The dynamics of ovarian follicular development and the pattern of pituitary and ovarian hormone concentration were investigated during the luteal phase in ewes with autotransplanted ovaries. The follicles were measured by ultrasound and samples of ovarian and jugular venous blood were collected at intervals of 12 h. Blood samples were collected before and after a GnRH challenge (250 ng GnRH, i.v.) to allow the determination of basal and LH-stimulated concentration of ovarian steroids. Throughout the luteal phase, large antral follicles developed in three waves, each of which was preceded by a rise in the concentration of FSH (P < 0.05). The concentrations of oestradiol and androstenedione in the unstimulated and LH-stimulated samples were similar (P > 0.05) during the first 3 days of the luteal phase but differed thereafter, with the LH-stimulated being significantly higher than the basal concentrations (P < 0.05). In the first wave of follicular development the changes in follicular size were accompanied by an increase in the concentration of ovarian steroids and inhibin A. During the second follicular wave, although changes in follicle diameter were similar to the first wave (P > 0.05), the basal concentration of ovarian steroids and inhibin A remained unchanged throughout the period of emergence and demise of the large follicles. These results confirm that the development of large antral follicles during the luteal phase of the sheep occurs in successive waves that are associated with fluctuations in FSH secretion. However while the results strongly suggest that fluctuations in both inhibin A and oestradiol secretion control FSH during the first follicular wave, the cause of the FSH fluctuations associated with waves two and three is unclear. Final resolution of this issue may need to await the development of a specific assay for dimeric inhibin B.     

Surface structures of synthetic diamonds

Diamond crystals of about 2 mm in size were grown by the temperature gradient method using Ni, Ni-Fe alloy and Fe as solvent metals. Several characteristic patterns were seen on the surfaces of the grown diamonds and were found to correspond to the texture of the quenched solvent metals. A vague vein-like pattern appeared when Ni was used. The surface patterns became finer with the increase of the content of Fe in Ni-Fe alloy, and when 70 wt% Fe-30 wt% Ni alloy was used, very fine dendritic patterns were seen on all of the faces of diamond in accordance with the symmetries of the lattice. The patterns are formed by the precipitation of carbon atoms in the space of the dendrites of the solvent metals during the quenching process. Lamellar patterns and etch pits were seen when Fe was used. The patterns are formed when Fe dissolves the diamond surfaces to produce Fe₃C during the quenching process.     

Improvement of the precision of the gradient method and object tracking using optical flow

In this study, the spatial local optimization method was improved to obtain high precision of optical flow for cases in which the object movement changes substantially and a method to trace the loci of moving objects was considered. In the spatial local optimization method, the precision of the optical flow when the object movement changes substantially becomes a problem. Therefore, to make the object movement relatively small, we obtained flow vectors from the image sequence to drop the resolution of the original input image sequence to half the initial resolution. flow vectors were then obtained from the original input image sequence that were smaller than the threshold value. We show that the precision of the optical flow when the object movement changes substantially is improved by this method. Method used to trace the loci of moving objects was demonstrated. We obtained clusters from histograms of flow vectors and pursued each cluster. We show that it is possible to trace moving objects by this method. This work was presented, in part, at the 7th International Symposium on Artificial Life and Robotics, Oita, Japan, January 16–18, 2002     

THE SEPARATION OF NEPTUNIUM AND TECHNETIUM IN AN ADVANCED PUREX PROCESS

ABSTRACT

An advanced PUREX process has been developed which can reduce TRU waste volume and the environmental hazard risk due to long-lived nuclides. The separation of neptunium and technetium from plutonium and uranium solutions has been studied before the U/ Pu partitioning step in the PUREX process. The effectiveness of normal-butyraldehyde as a reductant of Np( VI) to Np( V) and of high acid scrubbing of technetium was shown in a basic study and a chemical flowsheet study.     

DISTRIBUTION OF N- AND ISO- BUTYRALDEHYDES BETWEEN TRI-N-BUTYL PHOSPHATE/ N-DODECANE AND NITRIC ACID

ABSTRACT

The distribution of n- and iso-butyraldehydes between tri-n-butyl phosphate(TBP) n-dodecane(nDD) and HNO₃ were measured. The distribution ratio of n-butyraldehyde in the TBP/nDD and HNO₃ system was nearly the same as that of iso-butyraldehyde. The distribution ratios of n- and iso-butyraldehydes increased with TBP concentration in the organic phase. The equilibrium constant of the extraction reaction was about 2. In a uranium, neptunium and plutonium separation process, most of the n- and iso-butyra1dehydes fed into theNp separation stepor into thePu/U partition will be left with the TBP solvent. The two compounds will be partly back-extracted to the aqueous phase in the U purification and in the solvent washing steps of the PUREX process.     

Surgical therapy for hepatocellular carcinoma with liver cirrhosis

Approximately 80% of hepatocellular carcinoma (HCC) patients in Japan have associated liver cirrhosis, which increases the difficulty of surgical treatment. Liver dysfunction associated with liver cirrhosis is one of the most important predictive prognostic factors for HCC patients. Percutaneous ethanol injection therapy (PEIT) is useful for patients with small HCC or with poor hepatic functional reserve. Transcatheter arterial chemoembolization (TACE) is also useful both for patients with unresectable HCC and patients with multiple intrahepatic recurrence. Liver resection, however, lead to better outcome than other treatments when liver function is maintained after surgery. To determine operative procedures, it is important to evaluate the exact function of remnant liver, based on the preoperative liver function test and the evaluation of tumor character. For advanced HCC patients with vascular invasion, non-surgical treatments such as PEIT or TACE are not indicated, and surgical intervention can be an effective modality to improve their survival. Improvements of surgical technique and perioperative management have decreased fatal complications at a major liver resection and allowed us to carry out liver resection on patients with advanced HCC.     

Interfacial microstructure and strength of steel/aluminum alloy joints welded by resistance spot welding with cover plate

We joined aluminum alloy A5052 to cold-rolled steel SPCC (Steel Plate Cold Commercial) and austenitic stainless steel SUS304 using resistance spot welding with a cover plate. The interfacial microstructure was observed using transmission electron microscopy. A thick two-layered reaction layer contains Fe₂Al₅ and FeAl₃ and a thin serration reaction layer contains Fe₂Al₅ and FeAl₃ were observed at the A5052/SPCC and A5052/SUS304 interface, respectively. Mechanical property analysis suggested that the reaction layer has no effect on the tensile shear strength of the A5052/SUS304 joint and that the tensile shear strength of the A5052/SPCC joint is influenced by the reaction layer formed at its interface.     

Photocatalytic Inactivation of Legionella Pneumophila and an Aerobic Bacteria Consortium in Water over TiO2/SiO2 Fibres in a Continuous Reactor

A continuous photoreactor, working in a total recycle mode and irradiated by a low-pressure Hg lamp, has been used to study the bactericidal effect of a photocatalyst, formed by TiO₂ embedded in SiO₂ fibres, on Legionella pneumophila and a consortium of common gram-negative aerobic bacteria: (Escherichia coli, Klebsiella sp., Pseudomona sp. and Proteus sp.) in water. The kinetic modeling of the inactivation process, carried out with the measured values of viable bacteria concentration at the outlet of photoreactor, evidenced that for each pass inside the photoreactor the ratio between the outlet and inlet cell concentrations was of order of 0.01 for the inactivation of L. pneumophila. For the other aerobic bacteria, which are usually taken as reference in photocatalytic bacteria inactivation studies, this ratio was of order of 0.3 for the first hour of illumination, while upon prolonged irradiation (up to 9 h) this ratio increased to 0.7. Several factors inducing this latter decrease of efficiency are possible, as e.g. competition for photocatalytic attack between microorganisms and organic compounds released by damaged bacteria or photoinduced alteration of a small fraction of still viable bacteria making them less interactive with the photocatalyst. The inactivation mechanism normally proposed for common bacteria involves an initial attack of the photogenerated radicals to the outer membrane; the consequent membrane dispersion allows the radicals to damage the cytoplasmic membrane. The higher lethality of the photocatalytic method observed towards Legionella: (in comparison to the other aerobic bacteria) is explained considering that the radicals attack the Legionella secretion system, which is adapted for high virulence and would become activated for and through adhesion to the TiO₂ surface. This attack would then be able to inactivate L. pneumophila without dispersing the outer membrane. Apart from this, the water flow through the catalyst fibres can facilitate the bacteria transport towards the anatase surface, and additionally the generated shear stress may help adhesion, at least for some bacteria as E. coli, contributing further to improve the photokilling efficiency; both factors may contribute to the efficiency of this photoreactor configuration.