| JaLCDOI | 10.18926/15442 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_28_1_87.pdf |
| Author | Motojima Isao| Kono, Iichiro| Nishigaki, Makoto| |
| Abstract | In recent years, construction or planning of large-scale underground structures, such as underground power plants, underground oil storage plants and nuclear power plants have been coming into consideration in Japan. To construct such as large-scale underground structures, one of the most important problems is to make clear beforehand the behavior of groundwater around these structures and the other is to carry out proper countermeasure of groundwater, so that these structures can be constructed safely and maintained stability over a long time period. This report describes the results of theoretical studies on the drain systems and at the same time, discusses the drain systems around the underground cavern for the practical underground power stations. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1993-11-30 |
| Volume | volume28 |
| Issue | issue1 |
| Start Page | 87 |
| End Page | 128 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307220 |
| JaLCDOI | 10.18926/15463 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_28_2_59.pdf |
| Author | Nishigaki, Makoto| Sun Yao| Kohno, Iichiro| |
| Abstract | In this paper, first, an elasto-plastic consitituve equation for unsaturated soil was developed by considering of the basically behavior of unsaturated soil. Second, the results of a number of triaxial test and a set of rigid foundation model tests were simulated by using this constitutive equation, the agreement between observed and computed results was satisfactory and confirms the possibilities of this constitutive equation. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1994-03-15 |
| Volume | volume28 |
| Issue | issue2 |
| Start Page | 59 |
| End Page | 75 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307850 |
| JaLCDOI | 10.18926/15492 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_25_1_59.pdf |
| Author | Kohno, Iichiro| Nishigaki, Makoto| Okada Junji| |
| Abstract | In this paper, we propose a method to determine the coefficients of permeability of the unconfined aquifer consisted of two different permeability layers. With mixing the conventional pumping test and falling head permeability test, the coefficients of permeabilitiy k(1) and k(2) were obtained. The validity of the proposed method is investigated by using the numerical simulation. As the results, it becomes apparent that the proposed method is applicable to real hydarulic problems. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1990-12-14 |
| Volume | volume25 |
| Issue | issue1 |
| Start Page | 59 |
| End Page | 69 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307472 |
| JaLCDOI | 10.18926/15393 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_30_2_15.pdf |
| Author | Oka, Hisao| Fujiwara, Shiro| |
| Abstract | An estimation of muscle fatigue is very important study and many laboratory researchers had done actively in this field. The excellent measurement and analysis methods, however, have not established yet. The aim of this study was to investigate the muscle fatigue of low back, caused by sitting on the vehicle seat for a long time. The muscle viscoelasticity and the EMG (Electromyogram) were measured. The authors proposed the objective muscle fatigue index that was obtained from the result of PCA (Principal Component Analysis) by using the measured varlables. The objective muscle fatigue index suggests an adequate correlation with the subjective fatigue on the vehicle seat. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1996-03-29 |
| Volume | volume30 |
| Issue | issue2 |
| Start Page | 15 |
| End Page | 20 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307965 |
| JaLCDOI | 10.18926/15400 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_27_2_11.pdf |
| Author | Oka, Hisao| Yamamoto, Tatsuma| Saratani Keiji| Tanaka Masahiro| Kawazoe Takayoshi| |
| Abstract | The use of dental implants has increased together with increases in the human life span and it has become an imperative subject for dentists to familiarize themselves with this treatment modality. Unfortunately, there has been no practical and quantitative method for in vivo evaluation of the stability of dental implants. In the tooth mobility examination, the tactile sense of natural teeth is different from that of dental implants. The authors have developed an automatic diagnosis system of tooth mobility for clinical use. The biomechanical mobility of peri-implantium is measured with a pseudo-random vibration, from which the viscoelasticity c1, c2, k of peri-implantium is obtained. The diagnosis system has been applied to the quantitative evaluation of the stability of implants : endodontics endosseous implants (titanium pin), endosseous implants (Bioceram). It has also been applied to the evaluation of the long-term prognoses of dental implantation (Bioceram) and the examination of Intramobile implant (IMZ), and the satisfactory results have been obtained. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1993-03-25 |
| Volume | volume27 |
| Issue | issue2 |
| Start Page | 11 |
| End Page | 17 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002308018 |
| JaLCDOI | 10.18926/15415 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_29_2_29.pdf |
| Author | Oka, Hisao| Fukuda, Takashi| |
| Abstract | 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. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1995-03-27 |
| Volume | volume29 |
| Issue | issue2 |
| Start Page | 29 |
| End Page | 37 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307199 |
| JaLCDOI | 10.18926/15416 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_26_1_43.pdf |
| Author | Bouzidi, Moncef| Koga, Ryuji| Wada, Osami| Kagawa, Naoki| Hai Xu| Kosaka, Megumi| Sano HIroya| |
| Abstract | A numerical technique called as "adjoint spectrum" has been proposed by the authors in a previous work. Two applications of it are presented here. It is demonstrated that by generalizing the aspect of adjoint spectrum it becomes possible to measure densities of mixed gases simultaneously. An experimental proof of this has been carried on and simultaneous measurement of densities of both methane and dinitrogen oxide was realized. On the other hand, it is also reported that frequency shifting of spectra, which is a cause of error in spectrometric measurements, can be corrected by exploiting the adjoint spectrum technique in connection with the Taylor expansion. Numerical examples showing the success of this method are reported as well. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1991-11-30 |
| Volume | volume26 |
| Issue | issue1 |
| Start Page | 43 |
| End Page | 49 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307796 |
| JaLCDOI | 10.18926/15446 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_22_1.pdf |
| Author | Oka, Hisao| Yamamoto, Tatsuma| |
| Abstract | Biomechanical impedance is relatively small compared to industrial mechanical impedance. Thus it is difficult to measure it precisely. A biomechanical impedance measuring system was developed for portable use by means of random excitation. This system doesn't require a fixed body and vibrator supporting apparatus. In order to obtain an impedance spectrum, the FFT processing is performed using a personal computer. The spectra of the biomechanical impedance which is measured on body surfaces depend on body positions and can be roughly classified into three spectra patterns : soft, stiff and intermediate. During the measurement, the measuring conditions (preload, diameter of the vibrating tip etc.) influence the results. However, it became clear that the linearity of the biomechanical impedance was satisfied in the limited measuring conditions. Accordingly it is possible to standardize the impedance and to compare it with the results under different measuring conditions. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1988-03-31 |
| Volume | volume22 |
| Start Page | 1 |
| End Page | 14 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307480 |
| JaLCDOI | 10.18926/15465 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_23_1_49.pdf |
| Author | Oka, Hisao| Yamamoto, Tatsuma| Isayama Yoshiharu| |
| Abstract | In the field of dental study it is most fundamental and necessary to estimate the condition of periodontium. In order to examine a mechanical characteristics of periodontium, the theoretical displacement response to periodontal mechanical model (three elements model) are strictly solved in case of some pulse excitations. Impact excitations (rectangular, triangular and half-cycle sine pulse) are given in physical and mathematical definitions and complete solutions to the impact excitations are provided. The triangular pulse excitation which is obtained by means of a fracture of pencil-lead is most suitable. The mechanical parameters of periodontium are given using this input excitation. This is experimentally confirmed by artificial tooth model. The obtained mechanical characteristic of the periodontal tissues can be applied to clinical diagnosis. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1988-11-22 |
| Volume | volume23 |
| Issue | issue1 |
| Start Page | 49 |
| End Page | 60 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307622 |
| JaLCDOI | 10.18926/15476 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_24_1_63.pdf |
| Author | Yamamoto, Yoshitake| Isshiki Hiromi| Oka, Hisao| Yamamoto, Tatsuma| |
| Abstract | There is no doubt that many people feel the peace of mind or the pleasures of senses in appreciating music. But the estimation of the effect is very difficult and the objective estimation can be hardly done. This study proposed the objective estimating method of human emotion utilizing galvanic skin reflex (GSR) which reflects a human psychological activity. In this method, not by individual response, but by the series of response and pattern of appearance of GSR, the emotional response under appreciating music was investigated. In the case of appreciation of the same classic music to several subjects, the individual GSR responses are random and remarkable characteristic could not be find on the results. However, on the patterns of appearance of GSR, the patterns obtaining from the same generation are much similar each other and the patterns obtaining from different generation are less similar. It was cleared that the same music gave different effect on different generations. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1989-11-29 |
| Volume | volume24 |
| Issue | issue1 |
| Start Page | 63 |
| End Page | 72 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307670 |
| JaLCDOI | 10.18926/15479 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_24_1_73.pdf |
| Author | Oka, Hisao| Isayama Yoshiharu| Yamamoto, Yoshitake| Yamamoto, Tatsuma| |
| Abstract | There is a small vibration which goes undetected by the naked eyes. It is called a microvibration (MV) or a minor tremor (MT). The MV on the body surface is expected to apply to a clinical examination of the autonomic nervous system. It is not cleared why and how the MV occurs, but there are many papers about its occurrence and clinical application. In this study, MV measuring system, its estimation and basic characteristics are examined. The difference between head MV and thenar MV, individual MV and diurnal and seasonal change are discussed. The power spectrum of MV is obtained using an autoregressive model. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1989-11-29 |
| Volume | volume24 |
| Issue | issue1 |
| Start Page | 73 |
| End Page | 80 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307633 |
| JaLCDOI | 10.18926/15488 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_25_1_37.pdf |
| Author | Bouzidi, Moncef| Koga, Ryuji| Wada, Osami| Kagawa, Naoki| Hai, Xu| Kosaka, Megumi| Sano, Hiroya| |
| Abstract | Is proposed a tunable diode laser absorption spectrometer system which employs a pulsed current to drive the diode laser still implementing a second-harmonic detection methods enhancing a signal to noise up to 104 times that the case without it. This system affords the lead-salt diode laser a higher operating temperature which allows a more compact deep cooling system. A principle is based on employing a gated integrator between the preamplifier and the lock-in amplifier. Investigations are made on the optimum selection of the gating aperture time interval as determined by response time of the infrared detector and the pulse width of the laser driving current. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1990-12-14 |
| Volume | volume25 |
| Issue | issue1 |
| Start Page | 37 |
| End Page | 50 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307549 |
| JaLCDOI | 10.18926/15495 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_24_2_31.pdf |
| Author | Oka, Hisao| Isayama Yoshiharu| Nakauchi Makoto| Yamamoto, Tatsuma| |
| Abstract | A small vibration on the body surface is expected to apply to a clinical examination of the autonomic nervous system. The vibration cannot be found by the naked eyes. It is called a microvibration (MV) or a minor tremor (MT). It is not cleared out why and how the MV occurs, but many papers about its occurrence and clinical application have been published. In this study, the typical spectrum of MV and the various causes of MV occurrence are studied. The relationships of MV with heart rate, muscle contraction and MV are discussed. The power spectrum of MV is obtained by using an autoregressive model. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1990-03-29 |
| Volume | volume24 |
| Issue | issue2 |
| Start Page | 31 |
| End Page | 40 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307725 |
| JaLCDOI | 10.18926/19591 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_31_2_21.pdf |
| Author | Oka, Hisao| Nakamura, Takahiko| |
| Abstract | In evaluating the stiffness of skin surface, internal structures such as bone and muscle often affect the measurements. In the present paper, acoustic random vibration is used to estimated the viscoelasticity of a silicone-gel model. This viscoelasticity, which includes two different stiffness strata, is first estimated using a mechanical impedance spectrum, which describes the relation between the depth and viscoelasticity of internal objects. This method is applied to the depth of a silicone-gel tumor model measured by ultrasound imaging and the viscoelasticity of internal gel can be accurately estimated. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1997-03-28 |
| Volume | volume31 |
| Issue | issue2 |
| Start Page | 21 |
| End Page | 27 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002309105 |
| JaLCDOI | 10.18926/19592 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_31_2_29.pdf |
| Author | Oka, Hisao| Ohshima, Masakazu| |
| Abstract | Knee replacement arthroplasty is indicated for the patient with advanced knee pain, knee deformation, and knee functional disorder. The aim of this study was to estimate loosening after a knee replacement arthroplasty. Loosening is measured by a frequency response function, and mobility by random vibration. The modal parameters for the knee joint are obtained by applying a modal analysis to the frequency response function. The values decrease as the knee joint prosthesis loosened. These parameters serve as an index for the condition between a thighbone and the prosthesis. The various indexes will greatly clarify the stage of advance in the loosening of knee-joint prostheses. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1997-03-28 |
| Volume | volume31 |
| Issue | issue2 |
| Start Page | 29 |
| End Page | 37 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002309172 |
| JaLCDOI | 10.18926/19634 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_32_15.pdf |
| Author | Mori, Masahiro| Oka, Hisao| |
| Abstract | In a stiffness estimation of living body, an internal structure under the skin influences the measured results. Because a different stiffness of body caused by bones and muscles is obtained. In this paper, by using a measurement system of mechanical impedance, the relations between a viscoelasticity and a distance from the surface of silicone-gel model is calculated. This relation is applied to silicone-gel tumor model and a shape and a viscoelasticity of semi-sphere silicone-gel tumous are estimated. The obtained results are expressed as a reconstructed 3-D image of shape / viscoelasticity. The revised curve-fitting of mechanical impedance and the cancellation of peripheral vibration influence are proposed in order to increase an estimation acccuracy. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1998-04-20 |
| Volume | volume32 |
| Issue | issue1-2 |
| Start Page | 15 |
| End Page | 22 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002309047 |
| JaLCDOI | 10.18926/19663 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_33_2_39.pdf |
| Author | Yanagi Makoto| Oka, Hisao| |
| Abstract | The acousicmyogram (AMG) is a mechanical phenomenon recorded at the surface of an active muscle. It is used to monitor force production, fatigue, and contractile properties of muscle. In this study, the new electrode with accelerometer for electrostimulation and acoustic detection. It consists of Ag-AgCl active electrode and solid-gel annular groud, and a very light piezoresistive accelerometer. The recorded AMG waveform depends on the pulse amplitude and duration of stimulation current and its lag from the electroatimulation is about 7 ms. The strengh-duration (S-D) curve (the threshold current for stimulation vs. pulse duration) describes the excitability of muscle. The left forearm is electrostimulated by using the same electrode and the muscle vibration (AMG) is recorded with accelerometer. During the muscle fatigue, the S-D curve changes and the current threshold increases under the same pulse duration. The rheobase of S-D curve increases gradually but the chronaxie hardly changes during muscle fatigue. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1999-04-27 |
| Volume | volume33 |
| Issue | issue2 |
| Start Page | 39 |
| End Page | 44 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002309185 |
| JaLCDOI | 10.18926/19666 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_33_2_45.pdf |
| Author | Yamada Nobuya| Oka, Hisao| |
| Abstract | It is difficult to evaluate a biomechanical properties quantitatively. The authors developed the measurement system of biomechanical properties formerly but it is on a large scale because of the use of personal computer. In this study, the portable measurement system of biomechanical impedance/mobility is developed. To establish a rapid measurement, a random vibration is adopted in input signal. The system consists of the measuring probe, amplifier, and a note-typed personal computer. The measurement probe is developed newly, and has an overall length of 9 ㎝ (without a handle) and a total weight of about 500 g. The measurement program is also developed and is available to any computer which is worked under MS DOS compatible in Windows 95/98 operating system. The biomechanical spectra of thigh, temple and forehead are obtained and they show three typical spectrum patterns. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1999-04-27 |
| Volume | volume33 |
| Issue | issue2 |
| Start Page | 45 |
| End Page | 50 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002309193 |
| JaLCDOI | 10.18926/15501 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_24_2_67.pdf |
| Author | Nago, Hiroshi| Maeno, Shiro| |
| Abstract | Many hydraulic structures are damaged by under flood flow and storm waves year after year. Many cases of dike and breakwater failure are caused by the suck out of sand from behind the revetment. This type of failure will be in close relation to the dynamic behavior of sand bed around the revetment. In this paper, from this point of view, we investigated the basic characteristics of such sand movement by small model tests and tried to explain the hydro- and soil-mechanical mechanism of this phenomenon theoretically. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1990-03-29 |
| Volume | volume24 |
| Issue | issue2 |
| Start Page | 67 |
| End Page | 78 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307928 |
| JaLCDOI | 10.18926/15391 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_27_1_33.pdf |
| Author | Shimada, Yukiyasu| Suzuki, Kazuhiko| Sayama, Hayatoshi| |
| Abstract | Neural nets have recently become the focus of much attention, largely because of their wide range of complex and nonlinear problems. This paper presents a new integrated approach using neural networks for diagnosing process failures. The fault propagation in process is modeled by causal relationships from the fault tree and its minimal cut sets. The measurement patterns required for training and testing the neural network were obtained from fault propagation model. The network is able to diagnose even in the presence of malfunction of certain sensors. We demonstrate via a nitric acid cooler process how the neural network can learn and successfully diagnose the faults. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1992-11-25 |
| Volume | volume27 |
| Issue | issue1 |
| Start Page | 33 |
| End Page | 44 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307902 |
