岡山大学工学部
Acta Medica Okayama
0475-0071
13
1979
Numerical Analysis of Oscillatory Combustion Phenomena generated in A Pipe-Type Combustor
1
24
EN
10.18926/15696
In this paper, is proposed a calculating method for the simulation of oscillatory combustion state, and comparisons between estimation results and experimental ones are carried out. With respect to the effects of geometric dimensions of combustion system, and of fueland air-flow rate conditions on characteristics such as an amplitude of oscillation, its fluctuation, and a frequency, a theoretical analysis presents a correct estimation of the phenomena. By use of this analysis, it becomes possible exactly to estimate the changes which take place in the combustion system. On the basis of the quantitative feature of the theoretical results, the influences of the factors such as ignition lag, wall temperature ratio, and heat transmission on the combustion oscillation are studied.
No potential conflict of interest relevant to this article was reported.
岡山大学工学部
Acta Medica Okayama
0475-0071
13
1979
Basic Characteristics of Squarewave Irwerter Circuit with Series R-L Load
45
52
EN
10.18926/15700
In this paper, the steady state operations of the
squarewave inverter circuit with a series R-L load are
discussed. The circuit consists of transistors and
feedback diodes. The basic equation is derived from its
equivalent circuit. Solving the basic equation with
steady state conditions, the instaneous value of the
load current i is derived. The period t(2) for which the
current flows from the supply to the load and the
period t(l) for which the current feedbacks through diodes
from the load to the supply are calculated from (i), and
the ratio of t(l) to t(2) is illustrated using power factor
of fundamental wave, pf, as a variable. The ratios of
transistor mean current I(tr), diode mean current I(D),
supply mean current I(s) to the load current I are illustrated using pf as a variable, too. In result, each current ratios to I is shown in simple expressione. The load current can be calculated simply using the coefficient reading off the figure. In addition, it becomes clear from the figure that the load current is scarcely influenced by the harmonic voltage in less than 0.8 of pf. The ratio t(2)/(t(1)+t(2)) calculated in squarewave voltage, shows the limit of pulse width control whose out put voltage is the squarewave.
No potential conflict of interest relevant to this article was reported.
岡山大学工学部
Acta Medica Okayama
0475-0071
13
1979
AC Chopper Circuit with Lagging Reactive Load
53
64
EN
10.18926/15702
An ac chopper circuit, which chops an ac voltage in a complete cycle for any lagging reactive load, is devised. The circuit is constructed of two ac-switches composed of power transistors and diodes. The load voltage is smoothly controlled by varying the time ratio of ac-switch. Transistors operate in a highfrequency chopping mode, thereby the ripples of the source current and the load current are easily filtered. Furthermore the input power factor of this model is better than that of the thyristor phase control circuit. In this paper, the construction and the driving method of this model are described.
No potential conflict of interest relevant to this article was reported.
岡山大学工学部
Acta Medica Okayama
0475-0071
13
1979
Computer Program for Numerical Evaluation of the work
65
81
EN
10.18926/15704
We try to evaluate the manual work numerically from a point of view of the homogeneousness and the simultaneousness of both hands using the results of the micromotion study. The weighted coefficient and the balance index are used to evaluate the homogeneousness of both hands. And the simultaneous index is used to evaluate the simultaneous movement of both hands. It is necessary to make a program in order to use efficiently the method to calculate the indexes or the coefficients. Therefore the computer program of these methods is mentioned in this paper.
No potential conflict of interest relevant to this article was reported.
岡山大学工学部
Acta Medica Okayama
0475-0071
13
1979
Computer Program of Line Balancing, Regarding Efficiency and Number of Stations as Variables
83
93
EN
10.18926/15706
To assign work elements to the work stations in an assembly or manufacturing line, various computer programs have been developed and used. And it does that the number of stations or the cycle time is even given. But in practice it is desirable to obtain the assignment which shows the highest efficiency of line balancing under all possible combinations of the number of stations and the cycle time. Therefore we propose a computer program of the assignment method in which the efficiency of line balancing, Ebb and the number of stations, NN are regarded as variables. In this method the minimum value (EEb) of efficiency and the constant term (d) by which Ebb is reduced are given previously. And for any COmbination of Ebb (EE<Ebb<lOO) and NN (l<NN<Nm : Nm calculated from EEb), the work elements are assigned to work stations, the precedence restrictions being used. Ebb is reduced by d from the ideal value (100) until the assignment to NN is obtained. The efficiency of
the obtained assignment, Ebo is calculated. As Ebb<Ebo<Ebb+d, the calculation is continued until the assignment to NN, which shows the maximum efficiency, is obtained. In this process NN varies from Nm to 1 by 1 by 1.
No potential conflict of interest relevant to this article was reported.
岡山大学工学部
Acta Medica Okayama
0475-0071
13
1979
Effects of the Fluctuation of Solute Concentration in Al-Zn Alloys on the Aging at Low Temperatures; Ⅰ. Measurements of Electrical Resistivity
95
117
EN
Mutsuo
Ohta
Teruto
Kanadani
Masuo
Yamada
Akira
Sakakibara
10.18926/15709
Aging process in Al-Zn alloys was studied by the measurements of the electrical resistivity when the alloy was quenched from a high temperature, about 300℃ (the first quenching temperature), to an intermediate temperature, between 110℃ and 230℃ (the second quenching temperature), held at this temperature for a time, quenched again into iced water and aged at a low temperature. Variation of the holding time at the second quenching temperature brings about the variation of the isothermal aging curves. Maximum resistivity of the isothermal aging curve, p(max) , decreases at first, passes a minimum and then increases to reach a stationary value as the holding time at the intermediate temperature increases. It is pointed out that this phenomenon is mainly due to the fluctuation of solute concentration and the vacancy concentration decreasing at the intermediate temperature.
No potential conflict of interest relevant to this article was reported.
岡山大学工学部
Acta Medica Okayama
0475-0071
13
1979
Effects of the Fluctuation of Solute Concentration in Al-Zn Alloys on the Aging at Low Temperatures; II. Electron Microscopy and Measurements of SAXS Intensity
119
132
EN
Mutsuo
Ohta
Masuo
Yamada
Teruto
Kanadani
Akira
Sakakibara
10.18926/15712
The effects of the fluctuation of solute concentration on the process of aging in Al-10wt % Zn alloy were studied by measurements of the intensity of small-angle X-ray scattering and by electron microscopy. Specimen was quenched from a higher temperature(T(Ql), mainly 300℃) to an intermediate temperature (T(Q2), 110~230℃), held there for a time, quenched again into iced water and aged isothermally at 0℃ or 40℃. Results obtained are as follows: (1) When the specimen was held at T(Q2) for a sufficient time and aged at relatively high temperatue(e.g. Ihr at 125℃ and aged at 40℃), a two-step increasing of both resistivity and integrated intensity was found. (2)
Each of the steps has characteristics of the formation of G.P. zones by the spinodal decomposition. (3) When the maximum resistivity(p(max)) takes a minimum, Size distribution of the G.P. zones, estimated from the difference between Guinier and Porod radii, is much broader than that at p(max) in the usual direct quenching. (4) When the holding time at T(Q2) is long enough, the size distribution at p(max) is as broad as that at
p(max) in the usual case. (5) After a prolonged aging under the condition that P(max) takes minimum, G.P. zones grow markedly and become oblate ellipsoidal with a major axis of about 20nm. (6) These results are consistently understood in terms of the fluctuation of solute concentration at T(Q2) and the change in the concentration of vacancies during annealing at T(Q2). That is, it is considered that these results are due to the difference in aging behavior between the regions of relatively high concentration and the ones of low concentration induced by the fluctuation.
No potential conflict of interest relevant to this article was reported.
岡山大学工学部
Acta Medica Okayama
0475-0071
13
1979
Aging and Reversion in Dilute Al-Ag Alloys
133
152
EN
Mutsuo
Ohta
Teruto
Kanadani
Masuo
Yamada
Akira
Sakakibara
10.18926/15715
Aging and reversion in dilute Al-Ag alloys are studied by means of the measurements of electrical resistivity. Results obtained are as follows: 1) Increase in the as-quenched resistivity is found for a low quenching temperature. This increase may be due to the fluctuation of solute concentration at the quenching temperature. 2) When the fluctuation exists in the alloy, the aging rate becomes slow and the maximum resistivity in the isothermal aging curve becomes small as the vacancyconcentration becomes low. The maximum resistivity becomes large again when the vacancy concentration becomes further lower, and finally the maximum does not appear. 3) These behaviors are explained in terms of the difference in the rate of growth of the G.P. zones in the regions of higher and lower solute concentration induced by the fluctuation and in terms of the change of this difference with vacancy concentration. 4) G.P. zones may be formed by the spinodal decomposition with indefinite surfaces at first, grown to larger ones with difinite surfaces and changed to ordered nzones in the alloy. 5) It is confirmed that G.P. zones are formed by the nucleation-and-growth mechanism also in Al-Ag alloys above the spinodal temperature.
No potential conflict of interest relevant to this article was reported.
岡山大学工学部
Acta Medica Okayama
0475-0071
13
1979
Coupling-Network Dependence of Locking Phenomena in Microwave Oscillators
153
162
EN
Kiyoshi
Fukui
Shigeji
Nogi
Masuo
Yamada
Akira
Sakakibara
10.18926/15717
A unified treatment of injection and mutual phase locking phenomena in microwave oscillators coupled by a network characterized by a Y-matrix is presented. Under certain simplifying assumptions, steady state solutions such as locking frequency and oscillation phase relation are given with emphasis placed on the coupling-network dependence of locking bandwidth. Also, some examples of locking system specified by y(21)=0, Y(21)= Y(12) and y21= -Y12 are briefly discussed.
No potential conflict of interest relevant to this article was reported.
岡山大学工学部
Acta Medica Okayama
0475-0071
13
1979
A Walsh Waoofonn Analyzer and Its Applications to Filtering of Pulse Signals
163
180
EN
10.18926/15719
A new waveform analyzer based on the Walsh transform is developed and is applied to a real-time filtering of fast pulse signals, and the linear filterings of time signals through the Walsh transform is discussed. The analyzer converts a solitary waveform during 16 μs into the 16 Walsh amplitude spectra in a hybrid manner: it has the sequency band from 62.5 kzps to 500 kzps. The spectra are parallelly held during 16 μs by analog integrators, while serially displayed by the CRT, and one of them is digitally read out. The spectra of the test waves are measured within the error rate of several per cent. The analyzer is applied to the correlative detection of the photoelectric pulse signals in a gasspectroscopic system using a pulse laser, and there composes the matched filter, which is useful for measuring the signals superposed by Gaussian noises with a high accuracy. For the real-time filtering of fast signals, the arithmetic convolution and the frequency power spectra are approximated using the complex Walsh transform.
These approximations are of practical use in 16 or 32 dimensions. Then, the matched filters for pulse peaking are given by the approximate convolution and by the dyadic convolution.
No potential conflict of interest relevant to this article was reported.
岡山大学工学部
Acta Medica Okayama
0475-0071
13
1979
Lower Bounds for Thermodynmnic Quantities of Classical Ionic Mixtures
209
218
EN
10.18926/15724
Exact lower bounds are given for thermodynamic quantities of ionic mixtures in the uniform background in d dimensions with three-dimensional (1/r) Coulomb interaction (d=2 and 3) and with d-dimensional Coulomb interaction (d=1, 2, and 3). It is shown that these lower bounds improve upon known ones and give values close to experimental results which are available in the case of d=3.
No potential conflict of interest relevant to this article was reported.
岡山大学工学部
Acta Medica Okayama
0475-0071
13
1979
Longitudinal Properties of Two-Dimensional Classical Electron Liquids
219
224
EN
10.18926/15726
The dynamic form factor and the dispersion relation of the plasma oscillation of two-dimensional classical systems of electrons with ordinary Coulomb interaction are obtained by numerical experiments in the domain of the plasma parameter 2.24≤√=(πn)(1/2)e(2)/T≤70.7, where n, e, and T are the areal number density, the electronic charge, and the temperature in energy units, respectively.
No potential conflict of interest relevant to this article was reported.
岡山大学工学部
Acta Medica Okayama
0475-0071
13
1979
An Adaptive Observer via Optimal Control Law
225
238
EN
10.18926/15728
This paper deals with the adaptive observer which estimates the states and parameters of unknown system. It is shown that the adaptive observer problem is reduced to the identification of the transformation matrix for an arbitrary designable observer. Moreover, the adaptive process of the unknown parameters is reduced to the linear optimal regulator problem. As the result, a new method is presented to obtain an appropriate adaptive process with good insight. And, in this identification, a linear filter is found to be also useful against noises in input-output data. To achieve high accuracy, a particular nonlinear
filtering can improve SN ratio only in the direction of the unknown vector. Even if SN ratio of input-output data has zero dB, sufficient accuracy can be accomplished within suitable correction time. This design algorithm seems to be rather straightforward and practical. Since input sequence is required to be only sufficiently general, the method
is applicable to on-line identification also.
No potential conflict of interest relevant to this article was reported.
岡山大学工学部
Acta Medica Okayama
0475-0071
13
1979
A GRAPH-THEORETIC STUDY OF THE MINIMUM FILL-IN PROBLEM FOR SPARSE MATRIX METHOD
239
248
EN
10.18926/15729
In this paper the minimum fill-in problem which arises at the application of the sparse matrix method for linear sparse systems is discussed from the graphtheoretic viewpoint and the author gives some results which can be directly introduced in the design of, so called, the optimal elimination ordering algorithm which gives the minimum fill-in(the number of zeros in coefficient matrix which become non-zero during the elimination process). Through this investigation only graphs are treated instead of the coefficient matrices for linear systems, and the elimination process for a matrix is equivalated to the vertx eliminations for the graph. Then, the results by the theoretical investigation are summarized as following: 1. Optimal elimination for each subgraph which is subdivided
appropriately from whole graph leads to the global optimum.
2. In each subgraph there are only two kind of eliminations. Furthermore, some numerical experiments show the characteristics of the subset of vertices, which subdivide a subgraph from the residual.
No potential conflict of interest relevant to this article was reported.
岡山大学工学部
Acta Medica Okayama
0475-0071
13
1979
Asymptotic Theory of Rayleigh Problem in Rarefied Gas
249
258
EN
10.18926/15732
The asymptotic theory of Rayleigh shear flow for large values of time is developed on the basis of the linearized Boltzmann-Krook equation. Asymptotic equations for mean velocity outside the Knudsen layer are obtained by employing the Hilbert expansion. Slip boundary conditions are derived from the analysis of the Knudsen layer adjacent to the wall. A solution of the asymptotic equation is obtained under the slip boundary condition and zero initial condition. Discussions are also made of the flow induced by a slowly oscillating flat plate.
No potential conflict of interest relevant to this article was reported.
岡山大学工学部
Acta Medica Okayama
0475-0071
13
1979
A Notion of Adjoint Spectrum in the Application to Air-pollution Monitoring
181
193
EN
Hiroya
Sano
Ryuji
Koga
Yoshihiro
Tanada
Megumi
Kosaka
10.18926/15722
This report deals with a notion of adjoint spectrum which is applicable to air-pollution monitoring by using pulsed lasers. Both Raman and absorption spectra of multiple gas complex are linear combinations of the spectra, each of which is specific to a gas species and its magnitude is proportional to the density. An extended formulation of the method of least squares is made in terms of a new notion, adjoint spectra, which visualizes the structure of the numerical filter. Applications of the derived numerical filters to the two methods are shown and features are described about the synthesized filters.
No potential conflict of interest relevant to this article was reported.
岡山大学工学部
Acta Medica Okayama
0475-0071
13
1979
A Performance Analysis For An Air-Pollution Monitoring Using A Pulsed Dye Laser
195
207
EN
Hiroya
Sano
Ryuji
Koga
Megumi
Kosaka
10.18926/15723
The maximally attainable accuracy of an airpollution monitoring system is investigated. The system is composed of a tunable pulsed dye laser as the light source, photodiodes as the opto-electric converter and a low noise electronic signal processor specifically designed by the authors. The extreme value of the accuracy is given in terms of the standard deviation of the attenuation. The value is 3.4×10(-4)[Nep√(pulse number)] for an averaged value for multiple laser shots. Also the wavelength reproduceability of a dye laser was examined, which resulted in that a computer should take a part in the wavelength control in order that this method should be feasible.
No potential conflict of interest relevant to this article was reported.