Kiyoshi Suzuki

On-machine trueing/dressing of metal bond grinding wheels by electro-discharge machining

Summary This paper describes a newly proposed method for carrying out effective and precise trueing and dressing of metal bond grinding wheels on an NC grinding machine or a machining center by utilizing wire or die sinking electro-discharge machining(EDM). The main feature of this method is that a staple ED unit is mounted on the NC table of the grinding machine. Thereby trueing for eliminating the eccentricity of wheels and for generating or correcting profiled wheels is carried out by the help of NC movement of the table, keeping the grinding wheel on a machine spindle. In order to prevent the influence of wear of a block electrode in die sinking EDM, another new method is proposed for shaping or correcting the form of the electrode with a cutting tool on the grinding machine by the help of NC movement of the table. The superior effects of the proposed methods have been confirmed in the case of grinding of ceramic material with cast iron fiber bond diamond wheels.

Genetic Regulation of GM2 Expression in Liver of Mouse

GM2 containing NeuGc was found to be a major ganglioside in the liver of most inbred strains of mouse we have examined so far. They were DBA/2, C3H/He, C57BL/6, BALB/c, and CBA mice. However, WHT/Ht mouse does not contain a detectable amount of GM2 (NeuGc) but has GM3 containing NeuGc as the major ganglioside in the liver. The positive expression of GM2 (NeuGc) was demonstrated in the liver of F1 hybrids between WHT/Ht and DBA/2 mice, as one of the possible combinations. Moreover, the expression of GM2 (NeuGc) in the liver was proved to be an autosomal dominant trait by ganglioside analysis of 34 individual mice of the F2 and backcross generations. WHT/Ht mouse was demonstrated to be a recessive homozygote lacking GM2 (NeuGc) expression. During the analysis, interestingly enough, the enhanced elongation of the sugar chain in the gangliosides from GM2 (NeuGc) to GM1 (NeuGc) and GD1 was observed in the liver of F1 mice and this elongation was segregated only in half members of F2 and backcross generations.

Congenital Hydrocephalus Revealed in the Inbred Rat, LEW/Jms

We studied the development of congenital hydrocephalus found in a colony of an inbred strain of Wistar-Lewis rats (LEW/Jms) at various intervals after birth. The disorder was transmitted as a simple recessive mendelian character. Hydrocephalic neonates were recognized 2 days after birth by stretching of the skin over the head. Death usually occurred between 10 and 20 days of age. The findings suggested the possibility of a disturbance of cerebrospinal fluid circulation resulting from primary occlusion of the 3rd or lateral ventricles during embryological development. In later phases, the hydrocephalus was aggravated by obliteration of the subarachnoid space and by stenosis of the aqueduct occurring secondary to compression of these structures from increased pressure within the brain. In some animals, external hydrocephalus occurred as a result of rupture of the occipital pole and the establishment of a direct communication between the lateral ventricles and the subdural space. We looked for antibodies against viruses that have been known to produce hydrocephalus in experimental animals and obtained entirely negative results.

Highly Efficient Grinding of Ceramics and Hard Metals on Grinding Center

Summary A machining center provided with necessary counterplans as a grinding center was used with a newly developed cast iron bonded diamond wheel in grinding of ceramics and hard metals. Highly efficient three dimensional form grinding was found to be possible by utilizing the rigidity and numerical control function of the machining center and the high toughness and grinding ratio of the grinding wheel. The maximum stock removal rate of 42000mm 3 /min in deep grinding of alumina and that of 2000mm 3 /mm/min in high feedrate grinding of silicon nitride were obtained. Decrease of grinding force and increase of stock removal rate were attained by inprocess dressing in creep feed grinding. Specially devised, numerically controlled tool paths for improving the grinding ability were proposed and the helical scan grinding among them was found to improve surface roughness.

Structural polymorphism of murine factor B controlled by a locus closely linked to the H-2 complex and demonstration of multiple alleles

New alleles of murine factor B (Bf) protein were demonstrated. When ethylenediaminetetraacetic acid (EDTA)-plasmas from inbred and wild mice were analyzed by isoelectro-focusing (IEF) and immunofixation, murine Bf proteins were visualized as distinct protein bands in all mice tested. Four variants of murine Bf could be demonstrated in a large number of tested mice: Bf 1 (isoelectro-focusing point (P.I.) range of 5.8–6.1) exemplified by B10 and B10.BR, Bf 2 (P.I. range of 5.8–6.0) exemplified by B10.MOL (OHM), Bf 3 (P.I. range of 5.6–5.9) exemplified by B10.MOL (TEN2) and Mus musculus (Mus m.) subspecies Chc, Bf4 (P.I. range of 6.0–6.3) exemplified by Mus m. subspecies Shh. The genetic linkage between S locus and Bf locus was studied with two backcross progenies — [B 10.BR × (B10.BR × Mus m. subspecies Chc)F1] and [B 10.BR × (B10.BR × Mus m. subspecies Shh)F1]. Totally, 256 backcross progenies were typed for Bf type and for Ss type (plasma level of the fourth complement protein regulated by S locus). The results indicated that murine Bf was controlled by a single codominant locus located close to the H-2 complex because no mouse showing recombination between Bf locus and S locus was found.

Development of a New Turning Center for Grinding Ceramic Materials

Abstract A grinding center based on an NC turning center has been developed for efficient external, internal or cam grinding of ceramic mechanical parts. The grinding center is provided with not only various grinding wheels, but also an ultrasonic grinding attachment for reducing grinding force during coring or expanding holes. The grinding center is also equipped with an on-machine wire electro-discharge trueing/dressing unit for metal bond diamond wheels. All the other revisions necessary for grinding ceramic materials have been made on the turning center. The developed grinding center was confirmed to have expected abilities in efficient grinding and form grinding.

Direct nitriding of large grains of aluminum with 2 mm size

Abstract Aluminum grains with 2 mm size have been completely nitrided in one batch process. Aluminum grains with added promoter (13.8 wt.% of Y(NO 3 ) 3 ·6H 2 O) were almost completely nitrided by heating at 1300°C for 2 h in N 2 atmosphere. It was deduced that aluminum was vaporized by heat of initial nitriding to react with nitrogen in vapor phase in a short period of time. Nitriding of large-sized aluminum was also attempted without additive. Electrolytically etched aluminum wires were also used as starting material. The aluminum wires without additive were also completely nitrided at 1300°C by preheating at 600°C for 2 h. It seemed that the oxide layer produced by a trace amount of oxygen in N 2 gas during preheating activated the initial nitriding. Finally, the complete nitriding of aluminum grains was achieved by preheating at 600°C, without the additive. The oxygen content in the product was only 0.3%, in spite of the oxidation of the aluminum surface. This is because the surface area of the aluminum grains with 2 mm size is relatively small.

Immunological properties of athymic nude mice born from homozygous (nu/nu) parents.

No significant differences were observed between nude mice (nu/nu) born of homozygous (nu/nu) parents and those born of heterozygous (nu/+) mothers in the percentage of Thy-1-positive cells or immunoglobulin (Ig)-bearing cells in the spleen as assessed by immunofluorescence. There were no significant differences in the antibody response to thymus-dependent antigen or in the number of background plaque-forming cells to this antigen. The antibody response to thymus-independent antigen was not impaired at all in mice born from homozygous parents as compared with other nude mice or euthymic mice. It was concluded that the Thy-1-bearing (T) cells observed in nu/nu mice and the capacity of these mice to respond to thymus-dependent antigens arose independently of maternal T cells and of the influence of the maternal thymus.

Production of short length steel fibre for composite material on a milling machine

Abstract New manufacturing process of short length steel fibre by maching for Steel Fibre Reinforced Concrete (SFRC) proposed by the authors was experimentally confirmed that the machined fibre has an excellent reinforcing effect in the concrete matrix, if the fibre is manufactured in suitable machining condition. This paper surveys the experimental works on the effect of machining condition to the fibre quality, which are conducted in the development of machined fibre. Furthermore, it is confirmed that this process could be successfully extended to the manufacturing of stainless steel fibre for refractories and fine metal fibre for general composite materials.

Fine Bending With Counter Pressure

Counter pressure bending is a new precision bending method to solve many technical problems in V-shape bending. As the tension side of the material is compressed by the counter plate, most materials including hard and rather brittle materials, can be bent without fracture occuring even when bending to a right angle with zero nose radius. Also, the camber along the bending line and the distortion of the edge as observed in a conventional bent part, is decreased to a great extent by the addition of counter pressure. The bottom shape accuracy of the bent part is also improved. Bottom striking at the end of bending stroke can be omitted and hence spring back can be controlled easily by the adjustment of the press stroke.