Effect of Shot-Peening on fatigue Strength of Metals. II : Effects on Decarburized Steels

The effect of shot-peening on the fatigue strength of decarburized Si-Mn spring steels was examined by the rotary-bending and the reversed torsional method. The effect was very striking and it was observed that the endurance limit at 10^7 cycles of decarburized steels, which was reduced by about 50 per cent of limit of the polished specimen on account of the soft layer only about 0.05mm in thickness, increased by 40～50 per cent as the result of shot-peening of the decarburized layer. It might be possible to recover the strength in the non-decarburized state by increasing the peening intensity

Studies on the Reaction of Thorium with Graphite at High Temperatures

The reaction of thorium metal with graphite was studied in the temperature range of 900℃ to 1600℃. It was found that the reaction rate was parabolic and the activation energy for the reaction was 53 kcal/mole below 1200℃. Marker experiments showed that the growth of the carbide film was due mainly to the migration of carbon. From these results the rate determining process of the reaction seems to be the diffusion of carbon through the carbide film formed on the metal surface. Hydrocarbons, yielded by hydrolysis of the carbide film, were analysed by the gas-chromatographic method, from which the ratio of ThC/ThC_2 in the carbide film was determined. The film formed below 1200℃ was composed of ThC only. However, in the film formed above 1300℃ the ratio of ThC/ThC_2 decreased with increasing temperature. These results were confirmed by the X-ray diffraction technique. Parabolic rate constants for ThC and ThC_2 formations and apparent rate constants for the carbide film growth were obtained from the rate constant of the total carbide formation and the ThC/ThC_2 ratio in the carbide. The activation energy for the ThC_2 formation was found to be 120 kcal/mole from the results above 1300℃. The diffusion coefficient of carbon in ThC was calculated from the rate constants for the carbide formation. The amount of thorium carbide which forms in a thorium blanket of a graphite matrix fuel reactor was estimated

The Reaction of Uranium with Graphite at High Temperatures

The reaction of uranium metal with graphite was studied in the temperature range of 800°to 1100℃. It was found that the reaction rate is parabolic and that the activation energy for the reaction is 59 kcal/mole. Marker experiments showed that the growth of the carbide film was due mainly to the migration of carbon. From these results the rate determining process of the reaction seems to be the diffusion of carbon through the carbide film formed on the metal surface. Hydrocarbon, yielded by hydrolysis of the carbide film, was analysed by the gas-chromatographic method. From these results it was confirmed that the film formed in this temperature range was composed of UC only. These results were confirmed by the X-ray diffraction technique. From these parabolic rate constants, the self-diffusion coefficients of carbon in UC were calculated. These values were extrapolated and found to agree well with Chubb\u27s results by tracer technique

Influence of Amines in the Brain and Gastric Wall on Development of Stress Ulcers

With a view to examining the influence of amines in the brain and gastric wall on the development of stress ulcers, the authors loaded rats with the stress of cold restraint after administration of the inhibitory agents of produce and metabolism of amines, and the following findings were obtained. 1. Noradrenalin contents in the brain were significantly reduced after stress. The reduction relatively induced vagotonia and developed ulcers. Accordingly, noradrenalin in the brain associates with the development of stress ulcers. 2. Serotonin contents in the brain were increased significantly after stress, unlike the changes of the noradrenalin contents. But serotonin in the brain was not associated with the development of stress ulcers. 3. Histamine and serotonin contents in the gastric wall were reduced significantly after stress and both amines were associated with the development of stress ulcers. 4. Either of histamine or serotonin in the gastric wall was not be able to be the main cause on the development of stress ulcers, and their association was almost the same degree

Relationship between Bilirubin Decreasing Rate "b" and Morbidity in Patients with Obstructive Jaundice

In the period from 1970 to 1985, 114 patients on whom secondarily operation for obstructive jaundice has been done were surveyed.In order to determine a good clinical indicator for predicting prognosis, we took total bilirubin level and the bilirubin decreasing rate "b". In the relationship between total bilirubin level and morbidity, no significant difference were noted in the groups of total bilirubin level below 4.9mg/dl, at 5.0-9.9mg/dl, and over 10.0mg/dl. While the rate of complication is estimated to be 25% in the good group classified by "b" value, 33.9% in the fair group and 73.5% in the poor group, respectively. Significant difference between morbidity in the good group and the poor (p<0.01), and in the fair and the poor (p<0.01) were noted. Thus we conclude that the bilirubin decreasing rate "b" is much better clinical indicator than total bilirubin level

Changes in Blood Coagulation and Fibrinolysis Systems after Hassab's Procedure for Portal Hypertension

The changes in the coagulation and fibrinolysis systems in 12 patients on whom Hassab's procedure was given for portal hypertension with liver cirrhosis (LC) were studied. The coagulation factors such as the platelet count, prothrombin time (PT) and fibrinogen level showed reduction before operation, while after operation these values showed significant increase. Whereas the fibrinolysis, the fibrinogen degradation products (FDP) showed no positive cases before operation, but after operation a significant rise was noted on the 7th day as the peak. It was observed from these findings that Hassab's procedure given on the cases with LC induced acceleration in the coagulation and fibrinolysis systems after operation, so that ample care should be taken for the complications including disseminated intravascular coagulation (DIC) or gastrointestinal bleeding

The Influence of Truncal Vagotomy on Acute Gastric Mucosal Lesion in Obstructive Jaundice

With a view to examining the influence of truncal vagotomy on acute gastric mucosal lesion (AGML) in obstructive jaundice, the authors prepared the non-vagotomized group and the vagotomized group of rats with obstructive jaundice. Further, cold restraint stress was loaded on the two groups for 30 min, and the following results were obtained: 1) The incidence of AGML in the vagotomized group before stress was inhibited to 17% in both the 3-week group and 4-week group, as compared to 33-38% in the non-vagotomized group. The incidence of AGML in the vagotomized group after stress was inhibited to 17% in the 3-week group and 33% in the 4-week group, as compared to 78% in the non-vagotomized group. 2) Gastric mucosal histamine (HA) contents in the vagotomized group before stress in both the 3-week group and the 4-week group were significantly increased (p < 0.05) as compared with the levels in the non-vagotomized group. As concerns gastric mucosal serotonin (5-HT) contents, however, no significant difference was noted between both groups. The contents of both amines in the gastric mucosa in the non-vagotomized group, a significant decrease (p < 0.05) was observed in both the 3-week group and 4-week group after stress, while in the vagotomized group no significant changes were found

Experimental Studies on Acute Gastric Mucosal Lesion Involved with Obstructive Jaundice: Mainly on the Changes of Amine Contents in the Gastric Mucosa on Cold Restraint Stress

The authors gave load of cold restraint stress to rats with obstructive jaundice and those on which biliary drainage was performed in order to examine the incidence of AGML, amine contents in the gastric mucosa, and gastric mucosal microcirculation, and the following results were obtained: 1) The incidence of AGML in the 3,4-week group of rats with obstructive jaundice and in the 4-week group of rats with biliary drainage after cold restraint for 30 min was increased markedly by 78% for each as compared with 22% in the control group. 2) The contents of histamine and serotonin in the gastric mucosa in the control group showed no significant change after cold restraint for 30 min, whereas the contents of both amines in the 3,4-week group of rats with obstructive jaundice and in the 4-week group of rats with biliary drainage were, respectively, significantly decreased after cold restraint. 3) Gastric mucosal microcirculation in the control group was prevented rather successfully, whereas that in the 4-week group of rats with obstructive jaundice after cold restraint for 30 min developed disturbance of gastric mucosal microcirculation due to congestion

Th-ThC Phase Diagram

The partial phase diagram in the Th-C system between pure Th and ThC was studied by metallographic and X-ray techniques and by measurements of electrical resistivity in quenched and slow cooled Th-C alloys. The peritectic point of the reaction, liq.+ThC⇄α-Th, was found at 16 at%C and about 1875℃ and the peritectic composition of ThC was 33 at%C. The eutectic reaction occurred at 1650℃ and its composition of α-Th and β-Th was 6.5 and <0.5 at%C, respectively. The α⇄β transformation temperature rose gradually with the carbon content up to 2.3 at%C and rose rapidly between the compositions of 2.3 and 3.7 at%C. The phase boundaries of α/ThC+α, ThC+a/ThC. ThC/ThC+ThC_2 and liq.+ThC/ThC were also established

Changes of Histamine Contents and Mast Cell Population in the Gastric Mucosa of Carbon Tetrachloride-Induced Cirrhotic Rats

For the purpose of clarifying the mechanism of gastric mucosal lesion complicated with liver cirrhosis, the authers examined the changes of histamine contents and mast cell population in the gastric mucosa of carbon tetrachloride-induced cirrhotic rats. The histamine contents in the gastric mucosa and the mast cell count in the superficial area of the mucosa were significantly increased spontaneously and reduced with cold restraint stress in cirrhotic rats. However, no reductions in the both factors were observed in normal rats. The incedence of gastric mucosal lesions in cirrhotic rats was 38%, while it was 0% in normal rats, and rose to 100% in the former against 28% in the latter with stress. The hexosamine contents in the gastric mucosa were significantly lower in cirrhotic rats than in normal rats. It is considered that in cirrhotic rats easy release of gastric mucosal histamine with stress, which is associated with degranulation of mast cells in superficial layer, results in development of gastric mucosal lesions, and that the reduction in defensive capacity may be one of the causes for the increase in mast cells