岡山大学工学部Acta Medica Okayama0475-00711021976The Effects of Time Constant and Absorption on Stress Measured by X-ray Diffraction Method113EN10.18926/15681The diffracted intensity of X-ray depends upon several physical and geometrical factors such as structure, multiplicity, absorption and Lorentzpolarization and measuring conditions such as time constant and scanning speed of detector on counter method[l]. For analyzing on the X-ray stress measurement, especially, profile shape of X-ray diffraction which is affected by geometrical factors such as absorption and Lorentz-polarization is very important. In order to eliminate these factors affecting the stress measured by using X-ray, the correcting factors were introduced and those theoretical values were calculated. After this theoretical calculation, it is found that as the half value breadth increases the difference between the stress measured by using X-ray and the corrected one becomes larger and larger under same measuring condition. When the ideal diffracted intensity of X-ray is assumed Cauchy distribution the measured stress depends upon measuring condition for same specimen, but it is independent of measuring condition in Gauss, distribution. Consequently, it is found that the stress measured by using X-ray must be corrected under each measuring condition and the method of correction is made clear and proved experimentally in this paper.No potential conflict of interest relevant to this article was reported.Acta Medica Okayama11991High-speed processing for obtaining three-dimensional distance image and its application365370ENYutakaTanakaHidekiTsukaokaHidetoshiTakedaKazuoHondaTakaakiSarai<p>A high-speed method of 3-D distance acquisition based on the triangulation principle is presented. This method uses conventional devices such as a CCD camera, a laser emitting semiconductor, and scanning mirrors; however, new circuits have been developed for detecting the position of spot image on the CCD. This development enables the high speed measurement and reduces the cost of the apparatus. Experiments showed that the apparatus and the method gave the practical measuring accuracy and speed, and it was found that the system is useful for image recognition. This method can easily display the stereoscopic image and cross-sectional figure of the object body. The method of real time processing has also been developed with the view to apply the device to the range finders for robots and blind persons</p>
No potential conflict of interest relevant to this article was reported.Okayama University Medical SchoolActa Medica Okayama0386-300X6932015Dynamic Finite Element Analysis of Impulsive Stress Waves Propagating from the Greater Trochanter of the Femur by a Sideways Fall165171ENTakaakiSaraiAkihiroTokumotoOriginal Article10.18926/AMO/53523Fall accidents are a common cause of femoral fracture in the elderly. The greater trochanter of the femur is often subjected to impact loading by a sideways fall, and thus it is worth studying the impulsive stress waves propagating in the femur. In this study, the impulsive stress was analyzed by the dynamic finite element method using a 3-dimensional model of the femur, and the influence of the fall configuration on the stress was discussed. The stress was concentrated around the femoral neck during the propagation of the stress wave, and the tensile maximum principal stress changed into compressive minimum principle stress on the anterior and medial sides of the neck. On the other hand, the compressive minimum principal stress changed into tensile maximum principle stress on the lateral side of the neck. The largest maximum principal stress during the impact loading was always larger in the neck than in the impact region. The largest absolute value of the minimum principal stress was found in the neck or the impact region depending on the fall configuration. The largest absolute values of the maximum and minimum principal stress were nearly equal, indicating that the bone fracture due to the tensile stress may occur around the femoral neck.No potential conflict of interest relevant to this article was reported.