JaLCDOI 10.18926/15507
FullText URL Mem_Fac_Eng_OU_24_2_99.pdf
Author Taniguchi, Takeo| Fujiwara Kohji|
Abstract This paper presents an effective solver for a large sparse set of linear algebraic equations, which appears at the application of the finite element and the finite difference methods in engineering field. Proposed method is a family of SKYLINE METHOD, and for faster computation on the vector processors the original skyline is modified with respect to following three items; the use of inner products of matrix operations, the removal of unnecessary numerical operations and the introduction of two-dimensional array for storing the data of coefficient matrix.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1990-03-29
Volume volume24
Issue issue2
Start Page 99
End Page 112
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307515
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 10.18926/15512
FullText URL Mem_Fac_Eng_OU_25_2_69.pdf
Author Tsuchiya Takao| Kagawa, Yukio|
Abstract A finite element approach to the calculation of nonlinear sound propagation is proposed. Under the assumption of a weak nonlinearity, a linearized one-dimensional equation is considered. The equation is discretized in space, and is then solved for time by using Newmark-β integration scheme, in which a numerical damping is devised. Some numerical demonstrations are made for the nonlinear sound propagation of a single-shot pulse in air. It is shown that the shock wave propagation is stably and accurately simulated by the introduction of the numerical damping.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1991-03-28
Volume volume25
Issue issue2
Start Page 69
End Page 80
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307747
JaLCDOI 10.18926/15516
FullText URL Mem_Fac_Eng_OU_25_2_115.pdf
Author Taniguchi, Takeo| Irie Hirotsugu|
Abstract Nested dissection method is an elimination method for a set of linear algebraic equations with minimum fillins. Physically it divides a domain into four subdomains, and each subdomain is again divided into four. This procedure is repeated till all nodes are included in some subdomains. Using this characteristic, the authors examine the efficiency of the method on the transputer.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1991-03-28
Volume volume25
Issue issue2
Start Page 115
End Page 122
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307316
JaLCDOI 10.18926/15762
FullText URL Mem_Sch_Eng_OU_18_1_1.pdf
Author Nakata Takayoshi| Takahashi Norio|
Abstract The quantitative analysis of localized flux distributions in transformer cores has become easy through the progress of numerical field calculations. In this paper, the effects of core constructions, joint configurations, magnetizing characteristics of materials on the flux distributions are examined using newly developed techniques such as a gap element, an approximate method for solving three-dimensional magnetic fields, the time periodicity finite element method, an efficient technique for treating hysteresis characteristics and so on. A method for the optimum design of transformer cores is also discussed. Main results obtained can be summarized as follows: (a) The building factor of the core made of higely-oriented silicon steel is larger than that of the conventional core. (b) The iron losses at joints are much affected by overlap lengths, number of laminations per stagger layer and a small irregularity of the arrangement of sheets. (c) It is clarified that examinations of the optimum construction of core and the most desirable magnetic characteristics of core material are possible using the finite element method.
Publication Title Memoirs of the School of Engineering, Okayama University
Published Date 1984-03-30
Volume volume18
Issue issue1
Start Page 1
End Page 31
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307976
JaLCDOI 10.18926/15764
FullText URL Mem_Sch_Eng_OU_18_1_33.pdf
Author Osaki Hirokazu| Miyake Hirofumi| Kikuchi Susumu| Ogata Masana|
Abstract In this paper, we mentioned the apparatus developed to measure CFFs at the various point of the retina. Eleven CFFs measured at the central retina of both eyes (used usually} simultaneously, at the central retina of each eye separately, and at four points of the peripheral retina of each eye were analyzed together and referred to as the multi-point critical flicker fusion frequency (MCFF) . MCFF can be used to estimate the level of cortex activity, since the temporal and nasal parts of each eye are connected to different visual cortexes through the optic nerve. As the apparatus used to measure the MCFF was controlled by a micro-computer, the order of measurements and the calculation were done automatically.
Publication Title Memoirs of the School of Engineering, Okayama University
Published Date 1984-03-30
Volume volume18
Issue issue1
Start Page 33
End Page 42
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307595
JaLCDOI 10.18926/15767
FullText URL Mem_Sch_Eng_OU_18_1_43.pdf
Author Ohzuku Tsutomu| Hirai Taketsugu|
Abstract An equation on the current-polarization voltage characteristics of single charge transfer redox reaction on a rotating disk electrode (RDE) was given and a curvefitting method to determine kinetic parameters from an observed polarization curve was proposed therefrom. The method was demonstrated for Fe(2+)/Fe(3+)redox reaction in acidic aqueous electrolyte on Pt-RDE and the limitation of the method was discussed. The extension of the method to multistep charge transfer reaction was also considered.
Publication Title Memoirs of the School of Engineering, Okayama University
Published Date 1984-03-30
Volume volume18
Issue issue1
Start Page 43
End Page 56
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307914
JaLCDOI 10.18926/15768
FullText URL Mem_Sch_Eng_OU_18_1_57.pdf
Author Ohzuku Tsutomu| Sawai Keijiro| Hirai Taketsugu|
Abstract Basic kinetic equations of chronopotentiometric potential-time curves, in which the equations for reversible, quasi-reversible and irreversible electron transfer process appeared in special cases, were given and a chronopotentiometric method for determining kinetic parameters was proposed therefrom. The method was demonstrated for Fe(3+)/Fe(2+) redox reaction in acidic aqueous media. The limitations of the method and the double-layer charging effects on the potential-time curve were discussed. The extension of the method to more general electrode processes was also considered.
Publication Title Memoirs of the School of Engineering, Okayama University
Published Date 1984-03-30
Volume volume18
Issue issue1
Start Page 57
End Page 73
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307985
JaLCDOI 10.18926/15771
FullText URL Mem_Sch_Eng_OU_18_1_75.pdf
Author Ohzuku Tsutomu| Hirai Taketsugu|
Abstract A basic kinetic equation of potential-step chronoamperometric current-time curve controlled by the rates of diffusion and electron transfer for a simple one-electron charge transfer reaction was given and various features of current-time curves were deduced from a theoretical treatment. The current-time equations for reversible and irreversible electron transfer processes appear as special cases with limited conditions of the equation reported in the present paper. And a potential-step chronoamperometric method to determine kinetic parameters from a current-time curve was proposed therefrom. The extension of a basic kinetic equation to more general multistep charge-transfer process was also considered.
Publication Title Memoirs of the School of Engineering, Okayama University
Published Date 1984-03-30
Volume volume18
Issue issue1
Start Page 75
End Page 89
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307131
JaLCDOI 10.18926/15774
FullText URL Mem_Sch_Eng_OU_18_1_91.pdf
Author Sano, Hiroya| Koga, Ryuji| Kosaka, Megumi| Wake, Ichiro|
Abstract This paper presents an optical-waveform synthesizer as one of the applications of optical bistable devices. This device is advantageous in terms of faster operation in which width of each pulse obtained is down to the order of subnanosecond, because this device employs both GaAs- and Si-optoelectronic switches as photodetector. Optical pulse shaping as a preliminary experiment is also described.
Publication Title Memoirs of the School of Engineering, Okayama University
Published Date 1984-03-30
Volume volume18
Issue issue1
Start Page 91
End Page 100
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307204
JaLCDOI 10.18926/15775
FullText URL Mem_Sch_Eng_OU_18_1_101.pdf
Author Mori Chuji| Hattori Susumu|
Abstract In stereo matching of images, sample cross-covariances are used commonly as a criterion for deciding whether matched points are truly conjugate. Hereupon window width is a serious parameters to dominate matching stability. This paper argues about relation of matching stability with window width in terms of statistical behavior of sample covariances. For simple circumstances of analysis auto-covariances of a single image are considered instead of cross-covariances of stereo ones. First the mean and variance of sample auto-covariances are derived with parameters, window width and positional lag. Secondly they are evaluated from the correlation function estimated on an aerial image under the assumption of ergodicity to observe how they vary according as two parameters vary. From this result a variation factor is proved usefull to estimate appropriate window width.
Publication Title Memoirs of the School of Engineering, Okayama University
Published Date 1984-03-30
Volume volume18
Issue issue1
Start Page 101
End Page 110
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307207
JaLCDOI 10.18926/15778
FullText URL Mem_Sch_Eng_OU_18_1_111.pdf
Author Taniguchi Takeo| Matsumoto Takumi| Mitsuoka Kazuhiko|
Abstract The convergence condition of the explicit difference method for the heat transfer problem is aiready obtained. On the other hand, if the problem is formulated by using the weighted residual method for spatial axis, we have no tool to estimate the critical timestep width. In this paper, the estimation method is theoretically presented, and its propriety is examined through a number of numerical experiments.
Publication Title Memoirs of the School of Engineering, Okayama University
Published Date 1984-03-30
Volume volume18
Issue issue1
Start Page 111
End Page 130
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307658
JaLCDOI 10.18926/15781
FullText URL Mem_Sch_Eng_OU_19_1_1.pdf
Author Totsuji Hiroo|
Abstract Emission and absorption coefficients of bremsstrahlung by high-temperature partially degenerate electrons are calculated for high-density plasmas where Coulomb coupling between ions is not weak. It is shown that the ion correlation substantially reduces these coefficients.
Publication Title Memoirs of the School of Engineering, Okayama University
Published Date 1984-11-26
Volume volume19
Issue issue1
Start Page 1
End Page 12
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307955
JaLCDOI 10.18926/15782
FullText URL Mem_Sch_Eng_OU_15_2_133.pdf
Author Mori Chuji| Taniguchi Takeo| Kimoto Teruyuki|
Abstract From the theoretical approach to the fill-in minimization problem we present one of the optimal vertex elimination process for a regular finite element mesh M (nxn), and through a number of numerical experiments it is verified that the new process model can always lead to better numerical results comparing to other methods presently in use. Since the process here presented cann't give the actual dissections of M but can clarify how the optimal elimination is, the process includes George's Nested Dissection Method and the method by Duff, Erisman and Reid. By this investigation we can conclude that l) the concept of "Dissection" is neccessary for minimizing the number of fill-ins, 2) the location of the dissection lines can be systematically decided even if n of M is odd or even number, and though the interior area of M is dissected as George's Method, the surrounding area of M is rather irregularily dissected, and 3) the model of the vertex elimination process given in this paper is applied to other kind of regular finite element mesh or finite difference mesh, too.
Publication Title Memoirs of the School of Engineering, Okayama University
Published Date 1981-03-30
Volume volume15
Issue issue2
Start Page 133
End Page 146
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307564
JaLCDOI 10.18926/15783
FullText URL Mem_Sch_Eng_OU_19_1_13.pdf
Author Nago Hiroshi| Maeno Shiro|
Abstract In this paper the theoretical method to analyse the pore water pressures in the sand bed under the oscillating water pressure is developed. In the former researchs the validity of the theoretical treatment for the one-dimensional problem has been verified. However, the one-dimensional treatment is not sufficient to obtain the precise informations concerning the many practical problems. From this point of view, in this study, we derive the fundamental equations for the general three-dimensional sand layer under the oscillating water pressure. The validity of this theoretical method is verified by experiments for the twodimensional problems.
Publication Title Memoirs of the School of Engineering, Okayama University
Published Date 1984-11-26
Volume volume19
Issue issue1
Start Page 13
End Page 32
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307347
JaLCDOI 10.18926/15784
FullText URL Mem_Sch_Eng_OU_15_2_147.pdf
Author Nago Hiroshi| Kawara Osami|
Abstract In this paper, characteristics of hydraulics and water quality in Kojima Bay are discussed based on field observations. The main results obtained are as follows. (1) The variation of flow rate in Kojima Bay has periods for 30 minutes to 2 hours. This characteristic is represented by a two-dimensional numerical simulation fairly well. (2) The local distributions of salinity and suspended solids show increase in the direction to the mouth of Kojima Bay. On the other hand, the distribution of COD(Mn) is nearly uniform in the whole area of the bay. Salinity appears to be influenced by river discharge sensitively but suspended solids does not. (3) The vertical distributions of salinity and suspended solids are similar. There are similar points between the cross-sectional average of water quality and surface water quality. (4) The surface water quality seems to be influenced by the variation of velocity.
Publication Title Memoirs of the School of Engineering, Okayama University
Published Date 1981-03-30
Volume volume15
Issue issue2
Start Page 147
End Page 164
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002308021
JaLCDOI 10.18926/15785
FullText URL Mem_Sch_Eng_OU_19_1_33.pdf
Author Taniguchi Takeo| Soga Akira|
Abstract Numerical error in the solution of the band matrix method based on the elimination method in single precision is investigated theoretically and experimentally, and the behaviour of the truncation error and the roundoff error is clarified. Some important suggestions for the useful application of the band solver are proposed by using the results of above error analysis.
Publication Title Memoirs of the School of Engineering, Okayama University
Published Date 1984-11-26
Volume volume19
Issue issue1
Start Page 33
End Page 44
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307352
JaLCDOI 10.18926/15786
FullText URL Mem_Sch_Eng_OU_15_2_165.pdf
Author Inoue Hiroshi|
Abstract In this paper, the optimal toll-rate and scale of urban expressway is discussed economically. The criterion used is the total surplus of expressway, which is defined as the sum of consumer's surplus of expressway users and producer's surplus on the side of expressway administrator. The total surplus is equivalent to the difference of the value of total saved travel times of expressway users and the total cost required to construct and administrate expressway systems. The flow-dependent travel times is assumed, and traffic demand is induced through equilibrium method. On the other hand, for the management of expressway to be capable, the accounting condition that the fare revenue must repay the total cost should be satisfied. Under this accounting condition, the optimal rate and scale which maximize the total surplus are requested, and their properties are examined. The analysis is practiced for both caces of flowindependent cost function and flow-dependent cost function. One remarkable result is that the maximum feasible scale under the accounting condition does not privide a maximum for total surplus.
Publication Title Memoirs of the School of Engineering, Okayama University
Published Date 1981-03-30
Volume volume15
Issue issue2
Start Page 165
End Page 185
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307222