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We have developed a small size and high strength spiral bevel gear fabricated by five-axis controlled machining center. In the present report, we propose a novel spiral bevel gear with the rib at the end of face width to reinforce the tooth bending strength, which is machined with a ball-nose end-mill tool. We investigate the influence of the triangular rib on the bending stress both at the tooth root and around the rib and tooth deflection based on 1DCAE model, and demonstrate the effect of rib reinforcement at the proposed spiral bevel gear. Moreover, we compare the calculated stresses by 1DCAE with experimental ones from fabricated spiral bevel gear. As a result, a novel guideline is found to develop the small size and high strength spiral bevel gear with the rib at the end of face width from a view of rib shape.

We have developed a small size and high strength spiral bevel gear fabricated by five axis controlled machining center. In the present report, we propose a novel spiral bevel gear with the rib at the end of face width to reinforce the tooth bending strength, which is machined with a ball-nose end-mill tool. We investigate the influence of the rib shape on the bending stress at the tooth root based on 1D-CAE model and demonstrate the effect of rib reinforcement at the proposed spiral bevel gear. As a result, a novel guideline is found to design the small size and high strength spiral bevel gear with the rib at the end of face width from a view of rib shape.

In previous report, the interlock system of a pneumatic driving system have been studied and proposed based on the principle of safety. In this paper, we propose again that the interlock system is recognized high on the level of integrity as the safety-related parts of the international standard ISO13849. An accident may happen when failure of safety device may occur on the accidentally happened dangerous condition. It is a claim in this paper that in the safety system, failure of safety device shall not be simply in the safe side, it is necessary to stop the system by shutting off the power supply. The interlock system satisfies the function on the condition of fail-safe and it is recognized high level of the evaluation from the point of view of risk-based international standards (ISO12100, ISO13849). And it is further expected an ideal safety-related systems which may not give any harmful effects and that this system is also expected to be recognized as the top-level category of qualification. Conclusion of this paper is that there are no contradiction between differently based validation according to the international standards and the principle of safety.

POLEX program, as a sub-project of GARP, will start the 3 years' observation from 1979. And MAP will be opened from 1982. Based on these projects, the 21 st Japanese Antarctic Research Expedition will be set up with the meteorological satellite tracking and telemetry system at Syowa Station in Antarctica, and will receive the information of surface temperature, cloud, ozone and vertical temperature profiles. The analytic result of described information will make clear the circulation of the atmosphere, sudden warming in the spring, structure of a high latitude atmosphere, and the influence of middle upper atmosphere in the polar region affecting the general circulation of the earth's atmosphere.

Five cases of a persistent primitive olfactory artery are reported. The anomalous artery coursed anteromedially along the ipsilateral olfactory nerve and made a hairpin turn, supplying the circulation of the anterior cerebral artery. It was proposed that a primitive embryonic olfactory artery had remained as this artery. A cerebral aneurysm was located at the hairpin curve of the artery. Hemodynamic stress is considered to have an important role in aneurysm formation. Any aneurysm occurring at an artery should be considered for surgical treatment.

The optic nerve (ON) is sometimes distorted by an atherosclerotic internal carotid artery (IC) which we observe during operations. However the distortion seldom causes visual dysfunction. In this paper, 102 nonoperative cases without severe visual disturbance or marked effect on the visual system were studied, using coronal section of MRI and IC angiography, to ascertion ON distortion by IC. The grading of the distortion was determined by coronal section of MRI. Grade (Gr) 0: No distortion of ON, Gr 1: Distortion of ON without chiasmal dislocation, Gr 2: Distortion of ON with chiasmal dislocation. The rate of Gr 0, Gr 1, and Gr 2 were 62.7, 21.6 and 15.7%, respectively. The age of Gr 0, Gr 1 and Gr 2 were 55.4 +/- 19.6, 63.5 +/- 14.7 and 68.9 +/- 5.0 years old, respectively (Gr 2 was different from Gr 0). The occupying rate was calculated by the following formula. The areas were measured by IC angiography of the optic canal: The area of IC in optic canal/The area of optic anal x 100%. The rate of Gr 0, Gr 1 and Gr 2 were 24.2 +/- 19.8, 76.3 +/- 13.2 and 62.0 +/- 28.2%, respectively (Gr 1 and 2 differed from Gr 0). With a rate of more than 70%, the patient had ON distortion by IC.(ABSTRACT TRUNCATED AT 250 WORDS)

Three cases of intracranial hematomas which showed a fluid level presentation and/or mixed density in the acute stage by X-ray CT were reported. Case 1 is a 7-year-old boy who had the epidural and intracerebral hematomas three hours after the traffic accident. During the course, intracerebral hematomas which showed a fluid-level presentation had grown both 6 and 17 hours after the episode. Case 2 is a 39-year-old female who had received an aortic valve replacement 20 years ago. She was diagnosed as cerebral infarction due to the occlusion of the right middle cerebral artery. Intracerebral hematomas with a fluid level presentation developed in the infarcted area 20 days after the embolectomy. Case 3 is a 67-year-old female who had a mild subarachnoid hemorrhage by the traffic accident. Intracerebral hematoma with mixed density developed 68 hours after the episode and it enlarged again 89 hours after the accident. All three cases showed the abnormalities in the coagulofibrinolytic activities during the hemorrhage and showed a growth of the hematomas. It should be noticed that the case which shows a mixed density and/or a fluid level presentation in the X-ray CT requires more intensive care in both neurosurgical and general management.

Detection of an intraventricular or intratumoral fat-fluid level on the plain craniograms has been known as a characteristic sign indicating the presence of intracranial teratomatous tumors. On CT scans, however, only thirteen cases have been previously reported to be found an intraventricular and/or subarachnoid free fat associated with spontaneous ruptures of these tumors. We reported a case of pineal teratoma with intraventricular free-fat seen on CT scans. A nine-year-old male with precocious puberty was admitted to our hospital complaining a moderate nonpulsatile headache. Neurological examinations were normal without signs of meningeal irritation. The serum and CSF titer of HCG were raised markedly. The laboratory data of the CSF were normal and there were no pathological cells in the CSF. The CT scans revealed a large heterogeneous mass containing multiple areas of negative density in the pineal region. There were negative density droplets in the bilateral frontal horn on the same CT scans indicating a presence of free fats. At surgery, an yellowish oily material was drained from the tumor, but there was no sign of meningitis over the cortical surface of the occipital lobe. An intraventricular free fat on CT scan have been reported in fourteen cases including ours following the first case described by Fawcitt in 1976. Although most of the cases presented headache, only two cases was diagnosed clinically as chemical meningitis. Pathological changes indicating granulomatous meningitis, however, were noted in five cases, all of them presenting seizure attacks.

A case of traumatic occlusion of the bilateral vertebral arteries associated with fracture of the cervical spine is reported. A 34-year-old man, having no previously noted medical problems, fell to the bottom of a bathtub with a depth of 80 cm, and hit the vertex fronto-parietal region of his head. He was transferred to our hospital 6 hours after his fall with a crush fracture of the cervical spine at the C6 level. On admission he was alert, but having pain in the vertex region, dysarthria, blurred vision and hemiparesis. Roentgenograms confirmed a crush fracture of the C6 vertebral body. Computed tomograms of the brain revealed a high density of basilar artery. Cervical traction with a Halo brace was then carried out. Twelve hours after the trauma, left oculomotor and right facial palsy appeared followed by bilateral oculomotor palsy and respiratory difficulty. At the 14th hour, he displayed bilateral Babinski's signs and tetraparesis. Tetraparesis became complete with right-side Horner's syndrome at 16 hours. Cerebral arteriograms performed 20 hours after the trauma showed a complete occlusion of the right vertebral artery and an incomplete occlusion of the left vertebral artery at the C6-7 intervertebral disk space. Conscious level deteriorated to a 200 level on the Japan coma scale 28 hours after the trauma and to a 300 level after 32 hours. Computed tomograms revealed a marked low density on the cerebellum and brain stem 38 hours after the accident. He expired on the 22nd day after the trauma.(ABSTRACT TRUNCATED AT 250 WORDS)