JaLCDOI 10.18926/15506
FullText URL Mem_Fac_Eng_OU_25_2_17.pdf
Author Sakakibara, Akira| Kanadani, Teruto| Kaneeda, Toshiaki| Hosokawa, Norio|
Abstract Effect of the soft surface layer that was formed on low temperature aging of Al-Zn alloy on fatigue strength was studied under repeated tensile loading. Vickers microhardness test revealed that there existed less hardened region in the vicinity of grain boundary and surface, and that the region extends 50 to 100μm from the surface inward. From the plot of the stress amplitude against the number of cycles to failure, it is concluded that the presence of less hardened surface layer strengthens fatigue resistance of the age hardened Al-Zn alloys containing 8 to 16mass % Zn under the repeated tensile loading.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1991-03-28
Volume volume25
Issue issue2
Start Page 17
End Page 23
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307685
JaLCDOI 10.18926/15503
FullText URL Mem_Fac_Eng_OU_25_2_9.pdf
Author Mikuni, Masato| Hida, Moritaka| Nishida, Norihide| Sakakibara, Akira| Yamada, Masuo|
Abstract Strains induced in the Si substrates by TiN film were observed with X-ray topography. The image of the sample with TiN film 0.45μm thick was like that of a dislocation loop observed with transmission electron microscope. The images of the samples with TiN films 1.65, and 1.9μm thick were different; blackening spreaded in the <112> and <110> direction from the ring contrast in shape of four-lobed rosette pattern. Spreading extended 1.6 times longer than the radius of the ring contrast along the <112> direction. The strain field extended 0.1μm in depth from the top surface where TiN was plated. From the topographs of bent Si beam, it was found that the blackness was almost proportional to the strain. The strains induced by TiN film locally ion-plated were smaller than those observed previously when TiN was ion-plated on the whole top surface of the substrate. Fine structures were observed in the topographs which could not be explained by the kinematical theory.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1991-03-28
Volume volume25
Issue issue2
Start Page 9
End Page 15
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307429
JaLCDOI 10.18926/15508
FullText URL Mem_Fac_Eng_OU_25_2_25.pdf
Author Nsunge Felix Chintu| Tomita, Eiji| Hamamoto, Yoshisuke|
Abstract A suddenly started cold methane gas jet issuing from a 1 mm diameter orifice into still air at Mach one has been predicted using the two-equation, high Reynolds number version of k-ε turbulence model and SIMPLE algorithm which employs so called primitive variables and a hybrid scheme for treating combined diffusion and convection. Global trends of predicted radial distributions of velocity, temperature, methane concentration in the steady rear part of the transient jet and axial jet tip penetration compare reasonably well with universal profiles representing measurement for the steady jet particularly in the fully developed turbulent core and semi-empirical relation for the transient jet respectively. The prediction scheme has shown reasonably good accuracy especially in prediction of main flow parameters of a transient, high speed compressible gas jet issuing into a dissimilar surrounding gas(binary gas mixture jet).
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1991-03-28
Volume volume25
Issue issue2
Start Page 25
End Page 38
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307676
JaLCDOI 10.18926/15510
FullText URL Mem_Fac_Eng_OU_25_2_39.pdf
Author Nsunge Felix Chintu| Tomita, Eiji| Hamamoto, Yoshisuke|
Abstract Velocity distributions and related parameters of transient and steady, turbulent air jets issuing under atmospheric conditions at Mach 0.14, 0.33 and 0.5 have been predicted using Navier-Stokes(N-S) equations for compressible flow and incompressible flow independently with the k-ε model. The closeness and consistence of the results predicted by the N-S equations for compressible and incompressible flows as well as with relevant measurement or similar prediction show that the incompressible flow assumption for at least some subsonic gas jets issuing at velocities higher than Mach 0.3, the general limit for incompressible fluid flow, can be reasonably accurate particularly in the main fully developed flow region. This suggests that the divergence term in source terms of the momentum, turbulence energy and its dissipation rate equations have negligible effects for some seemingly compressible high speed, subsonic free gas jets. The computation time is reduced by at least 18 % when incompressible flow assumption is used.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1991-03-28
Volume volume25
Issue issue2
Start Page 39
End Page 54
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307456
JaLCDOI 10.18926/15511
FullText URL Mem_Fac_Eng_OU_25_2_55.pdf
Author Ohkura Akira| Kameyama, Yoshimasa| Sayama, Hayatoshi| Suzuki, Kazuhiko| Fukumoto Shuichi|
Abstract AHP can handle decision-making problems involving several criteria when some of these are difficult or impossible to compare other than numerically. When a small group of decision makers settle the multi-criteria problem by AHP, the members of group could not often reach an agreement with hierarchic structure involving objectives, criteria, sub-criteria and alternatives because they have different positions, interests, and opinions. Further, the members have different importances for criteria and sub-criteria, and have dissimilar preferences for alternatives. In this article, we reveal the troubleness of AHP in case of being used by a small group of decision makers. Moreover, we proposed a procedure of AHP which the members of group could easily agree with the structure of problem and the weights of criteria etc.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1991-03-28
Volume volume25
Issue issue2
Start Page 55
End Page 67
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307741
JaLCDOI 10.18926/15500
FullText URL Mem_Fac_Eng_OU_25_2_1.pdf
Author Okada, Hiroyuki| Hida, Moritaka| Sakakibara, Akira| Takemoto, Yoshito|
Abstract Tensile strength and elongation of cast magnesium reinforced with titanium fiber were measured by tensile test. The pull-out test of a titanium rod partially embedded in a magnesium matrix was performed to evaluate interfacial bonding strength between magnesium and titanium. It was found that when the fiber volume fraction was changed from 1% to 14%, the tensile strength was improved with increase of volume fraction, while the improvement of elongation tended to be restrained beyond the volume fraction of 10%. The interfacial strength was revealed to be strong, and this was substantiated by the scanning electron microscopy showing an excellent wettability between the titanium fiber and the magnesium matrix.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1991-03-28
Volume volume25
Issue issue2
Start Page 1
End Page 8
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307559
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 10.18926/15484
FullText URL Mem_Fac_Eng_OU_25_1_15.pdf
Author Sakakibara, Akira| Kanadani, Teruto|
Abstract Aging of Al-lmass % Ag alloy at 273K after quenching under various conditions was studied by measurement of electrical resistivity. Scattering of the quasi-equilibrium value of resistivity (p(e)) was not random but closely related to the as-quenched value (p(o)); P(e) increased with increasing p(o)' When the quenching temperature (T(q)) was lower than or equal to 773K, the state at p(e) was controlled substantially by the concentration of quenched vacancy. On the other hand, when T(q)>823K, GP zones formed during quenching played an important role, instead of quenched vacancies, in determining the state.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1990-12-14
Volume volume25
Issue issue1
Start Page 15
End Page 21
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307255
JaLCDOI 10.18926/15486
FullText URL Mem_Fac_Eng_OU_25_1_23.pdf
Author Miura, Yoshinari| Takada, Jun| Osaka, Akiyoshi| Kawamura, Toshio|
Abstract Zinc oxide films were prepared on silica glass substrates by the use of an r.f. activated reactive evaporation (ARE) method, and were examined by X-ray diffraction (XRD) and scanning electron micrograph (SEM). XRD measurements indicate that the films were c-axis oriented and that an r.f. plasma of Zn and O was necessary for the ZnO film deposition. Substrate temperature, oxygen gas pressure, evaporation rate, r.f. power and inlet position of oxygen gas effect the c-axis orientation, the growth rate and the microstructure of the films. Optimum conditions for a dense film with a fine texture of the surface and having good crystallinity were as follows: the substrate temperature;400℃, the evaporation rate;5.0(A)/s, the oxygen pressure;2.0x10(-4) Torr, the r.f. power;150 to 200W, and the oxygen gas inlet near the substrate. For the film prepared under the optimum conditions, the standard deviation σ of the rocking curve for the (002) diffraction was 1.9deg, smaller than that of the film prepared by using an r.f. sputtering method.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1990-12-14
Volume volume25
Issue issue1
Start Page 23
End Page 35
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307600
JaLCDOI 10.18926/15490
FullText URL Mem_Fac_Eng_OU_25_1_51.pdf
Author Totsuji, Hiroo|
Abstract The superconductivity proximity effect in the dirty limit is revisited and equations and boundary conditions are obtained for the case of inhomogeneous media with continuously varying characteristic parameters.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1990-12-14
Volume volume25
Issue issue1
Start Page 51
End Page 57
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307188
JaLCDOI 10.18926/15498
FullText URL Mem_Fac_Eng_OU_25_1_99.pdf
Author Nishigaki, Makoto| Takeshita, Yuji| Kono, Iichiro|
Abstract In this paper, a numerical procedure of determining hydraulic properties in multilayered aquifers are presented. From pumping test data in multilayered aquifers, the coefficient of permeability and specific storage for each aquifer are determined by using a combination of finite element analysis and nonlinear least-squares optimization technique. This study especially points out necessity of stress-flow coupling analysis to explain the behaviors of pressure head in multilayered aquifer during pumping test. As a example, practical pumping test data were evaluate and the coefficients of permeability and specific storage of aquifers and aquitard were obtained.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1990-12-14
Volume volume25
Issue issue1
Start Page 99
End Page 109
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307452
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 10.18926/15496
FullText URL Mem_Fac_Eng_OU_25_1_89.pdf
Author Abe, Hirofumi| Oishi Manabu|
Abstract Multidimensional scaling (MDS) has been used in a wide variety of research fields; psychology, political science, anthropology, marketing research, urban and regional planning, and so on. In practical terms, MDS is a statistical method to make a picture of the information in the data. It enables us to examine the "hidden structure" of a set of data. When the set of data is large, MDS is extremely useful, since it is easier and more informative to look at a picture than the data themselves. In this paper, MDS is applied to the interregional migration data of Japanese regions for the years 1960-85. Findings show that the two-dimensional configuration of regions estimated by MDS generally corresponds with the geographical locations of regions, and the structure of interregional migration was very stable over the study years 1960-85. It is also suggested that MDS is a useful tool to identify the relationships between regions using the spatial interaction data.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1990-12-14
Volume volume25
Issue issue1
Start Page 89
End Page 98
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307404
JaLCDOI 10.18926/15494
FullText URL Mem_Fac_Eng_OU_25_1_71.pdf
Author Myojin Sho| Yamada Masahito| Fujii Naoto|
Abstract A transportation planning way of approach is applied to optimal pricing and planning of urban expressway network. Two kinds of network are investigated ; four radials with one ring system and four radials with two rings system. The model is composed of three submodels ; road systell, trip generation-attraction and traffic diversion. Some iaplicative aspects are shown of the optimal solutions that maximize the aggregate number of the trips diverted to expressway under constraints ; equilibrium of revenue and expenditure and traffic capacity constraint. (1) traffic flow has the peaks at junctions on radial expressway that are adjusted to be equal to the traffic capacity. (2) two rings system realizes the larger aggregate number of diverted trips by lower toll rate than one ring system does. (3) well-located second ring has a remarkable effect on improvement in accessibility to expressway and (4) some parameters in the model have curious effects on the optimal system.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1990-12-14
Volume volume25
Issue issue1
Start Page 71
End Page 87
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307618
JaLCDOI 10.18926/15480
FullText URL Mem_Fac_Eng_OU_25_1_1.pdf
Author Gao Hong| Wada, Tsutomu| Noritsugu, Toshiro|
Abstract How to reduce and simplify the calculation for image recognition is a very attractive and important issue in order to realize the real time control of a robot based on the image recognition results. This paper describes a method of extracting 2 - dimensional geometrical features of cubic objects based on the normal vector distributions from the visual information obtained with the laser range finder to reduce the calculation of the image recognition. In this research a laser beam is scanned in the horizontal plane to which the cubic objects stand vertically and the laser spot is detected with a TV camera every sampling time. These spots make an intermittent locus which includes some special lines corresponding to the cubic objects. To extract the features of the cubic objects, we utilize the normal vectors formed on the locus. If some normal vectors distribute in the same direction and the origin of the normal vectors are very close to their neighbor's, these normal vectors can be classified into the same class, -the straight line class. Because the normal vectors on the neighbor surfaces of the cubic objects are vertical to each other, we use this property to determine the pair of straight lines which belong to the cubic objects. Making the histogram based on the normal vectors with the same direction, we obtain the peaks which are supported by the points on the cubic object surfaces. Then, the points can be extracted from the set of points on the whole locus inversely according to the relations with the peaks and the features of the cubic object can be extracted by applying method of least square to these extracted points. The experiments proved the availability of the proposed processing algorithm.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1990-12-14
Volume volume25
Issue issue1
Start Page 1
End Page 13
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002308010
JaLCDOI 10.18926/15502
FullText URL Mem_Fac_Eng_OU_24_2_79.pdf
Author Sato, Yoichiro|
Abstract In asynchronous arbiters, failures may happen, caused by metastable operations. The purpose of this study is to derive a formula to estimate such failures in a ring arbiter as mean time between failures (MTBF), under the condition that incidences of requests issued in all devices are different from each other. The operation of the arbiter is formularized by a markov chain. This chain is used to decide the probability at which each of possible failures contributes to MTBF. The sum of such probabilities gives the MTBF which can be represented as a sum of a finite number of terms. As an example, MTBF of a ring arbiter composed of 3 cells is shown.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1990-03-29
Volume volume24
Issue issue2
Start Page 79
End Page 87
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307486
JaLCDOI 10.18926/15497
FullText URL Mem_Fac_Eng_OU_24_2_41.pdf
Author Totsuji, Hiroo|
Abstract A possibility to control the microscopic superconducting channel based on the proximity effect is theoretically shown by a simple one-dimensional analysis of de Gennes' equation for the order parameter.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1990-03-29
Volume volume24
Issue issue2
Start Page 41
End Page 47
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307289
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 10.18926/15495
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 10.18926/15499
FullText URL Mem_Fac_Eng_OU_24_2_49.pdf
Author Mori, Chuji| Machida Ken-ichi|
Abstract Distance measurements have been more and more easy and accurate to carry out, and it is expected that distance mesurements may provide rather accurate results than angle measurements. Under these circumstances, caracteritics of errors in typical trilateration nets are investigated. The nets investigated are as follows: From single row of chains to pranimetrically extended nets in figure, open and closed networks with respect to external constraint, and with and without as to internal constraint. Computations are performed by use of the method of condition equations, and behaviours of error propagation and errors of coordinates of stations in the nets are shown in case of typical nets. For example, effects for decrease in error by composing a double row of chains and by enforcing external constraints are explained.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1990-03-29
Volume volume24
Issue issue2
Start Page 49
End Page 65
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307544