Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 29 2 1995 Backward Scheduling to Minimize the Actual Mean Flow Time with Dependent and Independent Setup Times 89 94 EN Kenji Sekoguchi Shigeji Miyazaki /10.18926/15430 The present paper deals with a new perfomance measure, the actual mean flow time, defined as a mean of the elapsed time of each job counted from the start time on a schedule to the corresponding due date. For the one machine backward scheduling model with a common due date and independent setup times, LPT schedule is shown as the optimal solution for the proposed measure. An optimal algorithm is presented for the case with dependent setup times on the basis of the algorithm by Arcelus and Chandra for a n / 1 / F forward scheduling problem. The proposed algorithm is coded in C-language and a computational experience is reported through a 16-bit computer. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 29 2 1995 Effect of Alcohol on Bioactivity of Glasses 83 88 EN Kanji Tsuru Chikara Ohtsuki Akiyoshi Osaka /10.18926/15428 One of the CaO,SiO(2)-based bioactive glasses(5OCaO･ 5OSiO (2) in mol%) were soaked for various periods in a simulated body fluid(SBF) with or without containing alcohols such as methanol, ethanol, and 1-propanol. Effect of the alcohols was investigated on the apatite formation on the glass surface with thin-film X-ray diffraction, FT-IR reflection spectroscopy and scanning electron microscopy. Under the presence of alcohols up to 0.1mol/l in the SBF an apatite layer was formed on the glass, while it consisted of crystallites similar in morphology but larger in size than that found for the SBF without the alcohols. It was concluded that the alcohols little influenced the the apatite forming ability of the CaO,SiO(2)-based glasses. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 29 2 1995 Ultrasonic Implantation of Bioactive Glass Particles into Poly(methyl methacrylate) Substrates 77 81 EN Kanji Tsuru Chikara Ohtsuki Akiyoshi Osaka 10.18926/15426 Poly(methyl methacrylate) substrates were immersed in suspensions containing bioactive 50CaO･50SiO(2) (mol%) glass particles (45 μm in diameter) and a 6:4 (volume fraction) mixture of ethanol and THF, and an ultrasonic energy was applied to the system. A layer of glass particles was implanted and covered more than 50% of the substrate surface. Thin film X-ray diffraction patterns and FT-IR reflection spectra indicated deposition of apatite on the glass-implanted substrates after they were soaked for 12 h in a simulated body fluid similar in apatite-deposition ability to the human blood plasma. Flake-like apatite crystallites formed on the substrate soaked in SBF for 3 days. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 29 2 1995 The Electronic Structure of C(60) Molecule -Structure of π-electron Band- 67 76 EN Chieko Totsuji 10.18926/15424 The π-electron band of C(60) molecule has been obtained by the tight binding approximation. Application of molecular orbital wave functions derived on the basis of the optimized bond orbital model gives, with simpler calculations, the results in satisfactory agreement with those of previous theoretical analyses. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 29 2 1995 One-Dimensional Classical Plasmas in Ion Traps, Ion Storage Rings, and Semiconductor Quantum Wires 57 65 EN Hiroo Totsuji /10.18926/15422 As plasmas with extremely reduced dimensionality, properties of one-dimensional classical plasmas are analyzed in the domain of strong coupling and static and dynamic structure factors and the plasmon dispersion relation are obtained. These plasmas may be realized in Penning traps with sufficiently strong confinement and also in semiconductor quantum wires under appropriate conditions. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 29 2 1995 Evaluation of Eigenmodes of Dielectric Waveguides by a Numerical Method Based on the BPM 49 55 EN Anis Ahmed Shinji Taniguchi Osami Wada Ming Wang Ryuji Koga /10.18926/15419 For weakly guiding dielectric waveguides, the eigenmode field distributions are calculated numerically with a simple algorithm. In this numerical method, the transverse sampling space can be chosen arbitrarily, and hence a narrow waveguide can be analyzed. The field satisfying scalar wave equation is expressed by the discrete Fourier transform and the mode eigenvalues and eigenfunctions are calculated by solving an eigenvalue equation numerically. The validity of this method is checked for 2-D waveguides having step and parabolic or square index distributions. It is found that for the well guided TE modes of the slab waveguide, the accuracy of this method is remarkably good, but some discrepancies are found if the mode is near cut off. In the problems where the normalized guide index b is small, caution should be taken in applying the results of this numerical method. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 29 2 1995 Correction of Apparent Viscoelasticity of Skin Surface 39 47 EN Hisao Oka Shun-ya Sakamoto 10.18926/15417 The body structures under the skin surface, such as bones and tendon, have an influence on the stiffness evaluation observed from the surface. In this case, the observed stiffness should be called an apparent stiffness. To obtain the biomechanical properties of skin itself, the influence of body structure should be removed. This study deals with the correction method of apparent viscoelasticity which calculated from apparent biomechanical impedance. This method is applied to the measured result of the forearm and the right chest to confirm its effectiveness. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 29 2 1995 Estimation of Body Structure by Biomechanical Impedance 29 37 EN Hisao Oka Takashi Fukuda 10.18926/15415 In the stiffness evaluation from the skin surface, the body structure under the skin, like a bone and muscle, influences on the measurement results. The authors developed the measurement system of biomechanical impedance with applying a vibration of acoustic frequency onto the body surface. We measured the viscoelasticity of the silicone-gel model, which involves metal blocks, from the gel surface by using this system. The internal structure of model is estimated from the relation between the viscoelasticity and the distance from the gel surface to the internal block. Applying this method, the shape of ribs of the right chest are estimated. The shapes and viscoelasticity of silicone-gel tumor model, which has two different tumors, are also estimated. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 29 2 1995 An Expert System for Reducing the Variety of Parts in Multi-item Production 23 27 EN Yasuhiro Kajihara Hirokazu Osaki /10.18926/15413 A method for reducing the variety of parts is proposed. The variety of parts in a product and the variety of parts among products are evaluated in consideration of some factors that influence the production cost. Rules are formulated for selecting parts which should be eliminated or whose designs should be changed to reduce these varieties. An expert system is developed based on this method for reducing the variety of parts. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 29 2 1995 A Method for Designing the Supplying Method of Parts to an Assembly Line 13 21 EN Hirokazu Osaki Yasuhiro Kajihara 10.18926/15411 We propose a method to design the supplying method of parts to an assembly line. Three types of supplying model (Serial, Parallel, and Mixed) are proposed based on the relation between the area of part and that of the transportation equipment. The part is supplied by the pallet on which the all parts of one product are arranged or by the lot of one part. AGV or conveyor are used to transport the pallet. The supplying model is evaluated from the total transportation cost calculated from the price of the transportation equipment and of land. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 29 2 1995 Numerical Study on Transient Heat Characteristics of a Rectangular Latent Heat Storage Vessel 5 12 EN Hideo Inaba Koichi Ozaki /10.18926/15409 Transient characteristics of the rectangular latent heat storage vessel packed with shape-stabilized phase change (solid-liquid) material (PCM) are investigated numerically by solving the governing equations of both the PCM and the heat transfer medium(water) simultaneously as a conjugate problem with the finite difference technique. It's found that the heat storage characteristics are greatly affected by the flow direction of the heat transfer medium since the natural and forced convection coexists in the heat storage vessel. That is, it is classified that the effectively thermal efficiency of the latent heat storage system is obtained by the downflow along vertical PCM for heat storage process and the upflow for heat release process. The effect of the inlet velocity of heat transfer medium(water) on transient heat characteristics of the latent heat storage system is also revealed in the present study. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 29 2 1995 Low Temperature Age-Hardening of Al-12mass % Zn-0.5mass % Cu Alloy 1 4 EN Akira Sakakibara Keiyu Nakagawa Teruto Kanadani 10.18926/15408 Effect of addition of a small amount of copper to Al- 12mass % Zn binary alloy on the process of low temperature aging is studied by hardness test and transmission electron microscopy. Age hardening rate after quenching from various temperatures is slowed down by addition of 0.5mass % copper to the binary alloy. The hardness obtained after long aging, however, is increased a little by the addition of copper. The extent of soft surface layer formed by aging in the copper-added alloy is nearly equal to that obtained in the binary alloy. No potential conflict of interest relevant to this article was reported.