JaLCDOI 10.18926/15344
FullText URL Mem_Fac_Eng_OU_35_1.pdf
Author Abe, Takeji| Hualin Song| Akagi Yasuo| Shimizu, Ichiro|
Abstract Free surface of polycrystalline metal becomes roughened after plastic deformation. The surface roughening is closely related to the inhomogeneity of polycrystalline metals, that is, to the inhomogeneous plastic deformation of respective grains. In the present study, inhomogeneous deformation on the free surface of polycrystalline aluminum specimen during uniaxial tension is studied. The inhomogeneous deformation of grains in the central area of the free surface of specimen is observed by the laser scanning microscope, while the inhomogeneous deformation perpendicular to the surface is studied by the laser scanning microscope as well as the stylus measuring instrument. It is shown that the surface roughness and the strain of respective grains increase with the applied strain. Discussions are made on the change in the surface roughness, the strain in each grain and the slip-line angles with the applied strain.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2001-03-27
Volume volume35
Issue issue1-2
Start Page 1
End Page 8
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307340
JaLCDOI 10.18926/46996
FullText URL mfe_36_1_007_016.pdf
Author Li, Yan| Abe, Takeji| Tada, Naoya| Kanazawa, Masanori|
Abstract The change in the surface morphology of polycrystalline titanium during tensile plastic deformation is studied, using the scanning probe microscope as well as the laser scanning microscope. The observation shows that the slip occurs mainly near grain boundary at the strain range of ε < 0.05. The slip develops with the applied strain, and the slip on the second slip system or the crossing of slip lines appear. The surface roughness increases linearly with the applied strain. The height difference between the grain boundary area and the inner grain area also increases with the applied strain, though the increase rate becomes low after the applied strain of about 0.3. The nano-scale height difference of the surface step of slip lines increases with the applied strain, though it remains almost constant after the applied strain of 0.4. The averaged surface roughness measured with the scanning probe microscope is in good agreement with that measured with the laser scanning microscope.
Keywords Plasticity Polycrystalline Titanium Tensile Deformation Surface Morphology Slip Twin Probe Scanning Microscope Laser Scanning Microscope
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2001-12
Volume volume36
Issue issue1
Start Page 7
End Page 16
ISSN 0475-0071
language 英語
File Version publisher
NAID 80012831215
JaLCDOI 10.18926/14135
FullText URL Mem_Fac_Eng_39_1_7.pdf
Author Wang, Xiaoqun| Abe, Takeji| Tada, Naoya| Shimizu, Ichiro|
Abstract Roughening on free surface of polycrystalline metal during plastic deformation is closely related to the inhomogeneous deformation in the respective grain at the surface. Uniaxial tensile tests are carried out on annealed pure aluminum sheet specimens with various averaged grain sizes. The roughening is measured by a 3-dimensional stylus instrument to examine the roughness change in both sides of specimen surfaces at each strain. The irregularities on one side are reversed on the backside, when the averaged grain size is as large as the thickness of the specimen. Discussions are made on the relation between the surface shapes of both sides adopting the cross correlation factor. The strains of respective grains are also measured from the grain boundary shape before and after plastic deformation. There are some deviations in the strains of the grains and their standard deviation increases with the applied strain.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2005-01
Volume volume39
Issue issue1
Start Page 7
End Page 15
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002308149
JaLCDOI 10.18926/19588
FullText URL Mem_Fac_Eng_OU_31_2_1.pdf
Author Arisawa Hideaki| Song Zhi-Yi| Takemoto, Yoshito| Hida, Moritaka|
Abstract The microstructure of oxidizing magnesium at elevated temperatures has been studied using HR-TEM, SEM and EDS. Two kinds of thin magnesium specimen for TEM observation were prepared. One was oxidized after preparing TEM foil of magnesium, the other was prepared from an oxidized bulk magnesium for observing the cross-section of oxide/Mg interfacial region. In the former, several oxides(MgO) morphologies were observed depending on the temperature and time of the oxidization. The growth of needle-like oxides formed at 573K and mottled oxides formed at 773K were recognized as a remarkable phenomenon belonging to the local oxidization. These oxides were composed of poly-crystal. The thin uniform oxidization layer was also observed in all conditions. In the cross-sectional observation, the local oxide layer, nearly 300nm in thickness, on the matrix(Mg) were observed. The thin uniform oxidized layer of bulk samples was identified as a kind of modified layer (~40nm in thickness) in which the formation of HR-TEM lattice fringes were prevented by the strain due to the slight oxidization.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1997-03-28
Volume volume31
Issue issue2
Start Page 1
End Page 10
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002309082
JaLCDOI 10.18926/15454
FullText URL Mem_Fac_Eng_OU_22_63.pdf
Author Myojin Syo| Kishino Keiichi| Yamada Masahito|
Abstract The paper is a case study mode choice in interregional occupational person trips. Disagregate behavioral model of logit type is applied to the occupational person trips from Tsuyama area in Okayama Prefecture to Osaka area. The model turned out to give asignificant explanation of the interregional mode choice characteristics. Travel time, travelling expenses and " with or wi thout heavy baggage " were found to be significant.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1988-03-31
Volume volume22
Start Page 63
End Page 70
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307421
JaLCDOI 10.18926/47001
FullText URL mfe_36_1_059_077.pdf
Author Kanatani, Kenichi|
Abstract Contrasting "geometric fitting", for which the noise level is taken as the asymptotic variable, with "statistical inference", for which the number of observations is taken as the asymptotic variable, we give a new definition of the "geometric AIC" and the "geometric MDL" as the counterparts of Akaike's AIC and Rissanen's MDL. We discuss various theoretical and practical problems that emerge from our analysis. Finally, we show, doing experiments using synthetic and real images, that the geometric MDL does not necessarily outperform the geometric AIC and that the two criteria have very different characteristics.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2001-12
Volume volume36
Issue issue1
Start Page 59
End Page 77
ISSN 0475-0071
language 英語
File Version publisher
NAID 80012855281
JaLCDOI 10.18926/46998
FullText URL mfe_36_1_029_039.pdf
Author Imai, Jun| Wada, Kiyoshi|
Abstract A procedure for control-oriented modeling is proposed for large flexible structures with unknown modal parameters. Techniques on quantification of errors in modal truncated nominal models are developed for the case where a finite number of upper and lower bounds of the unknown modal parameters are given. A feasible set of systems matching the conditions is introduced, and then error bounds covering the feasible set are established in the frequency domain. The bounds are easily checked using linear programming for any user-specified frequency. The feasibility of the proposed scheme is illustrated by numerical study on an ideal flexible beam example.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2001-12
Volume volume36
Issue issue1
Start Page 29
End Page 39
ISSN 0475-0071
language 英語
File Version publisher
NAID 80012887118
JaLCDOI 10.18926/15381
FullText URL Mem_Fac_Eng_OU_30_1_75.pdf
Author Totsuji, Hiroo| Inoue, Yoshihiko| Kishimoto, Tokunari| Totsuji, Chieko| Nara, Shigetoshi|
Abstract Molecular dynamics of the Yukawa system, the system of particles interacting via the Yukawa or the screened Coulomb potential, are formulated for various statistical ensembles and external conditions. The Yukawa potential smoothly interpolates the long-range Coulomb and the short-range interactions by adjusting a single parameter, the screening length. In order to reduce the effect of boundaries, the periodic boundary conditions are imposed and the deformations of the fundamental vectors of periodicity are taken into account. Ewald-type expressions for interaction energy, force, and kinematic pressure are given explicitly.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1995-12-28
Volume volume30
Issue issue1
Start Page 75
End Page 87
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307479
JaLCDOI 10.18926/15361
FullText URL Mem_Fac_Eng_OU_35_77.pdf
Author Kishimoto Tokunari| Totsuji, Chieko| Tsuruta, Kenji| Totsuji, Hiroo|
Abstract In order to perform the large-scale molecular dynamics simulation of the Yukawa system, a mathematical expression for molecular dynamics using the fast multipole method is described. The model simulations are also performed to test the performance of our implementation of the FMM.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2001-03-27
Volume volume35
Issue issue1-2
Start Page 77
End Page 95
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307940
JaLCDOI 10.18926/15418
FullText URL Mem_Fac_Eng_OU_26_1_51.pdf
Author Totsuji, Hiroo| Shirokoshi Hideki| Nara, Shigetoshi|
Abstract Variable shape molecular dynamics is formulated for the one-component plasma and the structural transition from the fcc lattice to the bcc lattice has been observed. It is emphasized that the condition of constant volume should be imposed when deformations of periodic boundary conditions are taken into account.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1991-11-30
Volume volume26
Issue issue1
Start Page 51
End Page 59
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307555
JaLCDOI 10.18926/47024
FullText URL mfe_36_2_043_049.pdf
Author Vaillancourt, Chico|
Abstract In this case study, I will analyse and discuss the results of a survey concerning motivation towards learning a second language conducted in four Canadian schools. This section, part one of the study, was conducted in the Sudbury Region of Ontario, Canada. This region of the world was chosen because bilingualism is quite common there and a large portion of the community has learned a second language. Part two will be conducted in the winter of 2002, in Denmark, a European country that neighbours many countries with different mother tongues, I hope to conclude this case study with part three in the summer of 2002, in Japan, a monolingual island nation.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2002-03
Volume volume36
Issue issue2
Start Page 43
End Page 49
ISSN 0475-0071
language 英語
File Version publisher
NAID 120003497045
JaLCDOI 10.18926/46980
FullText URL mfe_37_2_061_066.pdf
Author Vaillancourt, Chico|
Abstract In this case study, I will analyse and discuss the results of a survey concerning motivation towards learning a second language conducted in one Danish high school. The students surveyed were between the ages of 13-18. This section, part two of the study, was conducted in Copenhagen, Denmark. This region of the world was chosen because bilingualism is quite common there and a large portion of the school-aged community is learning a second language and often a third and even a fourth. Denmark, a European country, is different than Canada (Case Study-Part 1.) because it neighbours many countries, which use different mother tongues.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2003-03
Volume volume37
Issue issue2
Start Page 61
End Page 66
ISSN 0475-0071
language 英語
File Version publisher
NAID 120003457333
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 10.18926/19673
FullText URL Mem_Fac_Eng_OU_33_2_61.pdf
Author Totsuji, Hiroo| Tsuruta, Kenji| Totsuji, Chieko|
Abstract The behavior of multicomponent plasmas in the Penning-Malmberg traps is discussed with the parameters corresponding to experiments with antiprotons and cryogenic electrons. The relaxation times for the energy transfer antiprotons to electrons and between parallel and perpendicular components of electrons are estimated. It is shown that, depending on the values of parameters, both the former and the latter can be the bottleneck in the cooling process.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1999-04-27
Volume volume33
Issue issue2
Start Page 61
End Page 69
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002309106
JaLCDOI 10.18926/15397
FullText URL Mem_Fac_Eng_OU_30_2_1.pdf
Author Takemoto, Yoshito| Hida, Moritaka| Sakakibara, Akira|
Abstract The mechanism of brittle fracture in Ti-14mass % Mo alloy aged for 1x10(6)s at 623K was studied using transmission electron microscopy (TEM) and dynamic hardness test (DHT) on the structure deformed by means of tensile elongation at elevated temperature or cold rolling. Many band products were observed by TEM in either deformed specimens. These band products were identified to neither slips nor twinning bands, moreover, they were different from α , α ' and α " phases. The band product consisted of β phase and granular unknown phase which was transformed by deformation from ω phase. The newly discovered phase, named β" phase, in the band products had a body-centered triclinic structure. The β" was similar to the ω zone with respect to the morphology and the concentration of Mo, but it resembled β in structure. The result of DHT on the band products and the matrix showed that the band products were softer than the matrix. It is suggested that the band products are easily deformed because of the disappearance of obstacles such as ω phase, and consequently behave like paths to lead cracks preferentially.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1996-03-29
Volume volume30
Issue issue2
Start Page 1
End Page 7
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307225
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 10.18926/15358
FullText URL Mem_Fac_Eng_OU_35_63.pdf
Author Shinomiya Shigeru| Totsuji, Chieko| Tsuruta, Kenji| Totsuji, Hiroo|
Abstract We present a theoretical study of Si(1-x)Ge(x) alloys based on tight-binding molecular dynamics (TBMD) calculations. First, we introduce a new set of nonorthogonal tight-binding parameters for silicon and germanium based on the previous work by Menon and Subbaswamy [Phys. Rev. B 55, 9231 (1997); J. Phys: Condens. Matter 10, 10991 (1998)]. We then apply the method to structural analyses of Si(1-x)Ge(x) alloys. The equilibrium volume and atomic structure for a given x are obtained by the TBMD method. We also calculate the bulk modulus B, elastic constants C(11), C(12) and C(44) as a function of x. The results show that the moduli vary monotonically, but nonlinearly, between the values of Si crystal and Ge crystal. The validity of the results is also discussed.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2001-03-27
Volume volume35
Issue issue1-2
Start Page 63
End Page 75
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307673
JaLCDOI 10.18926/20012
FullText URL Mem_Fac_Eng_OU_29_1_15.pdf
Author Totsuji, Chieko| Matsubara, Takeo| Obuchi, Masumi|
Abstract A molecular orbital approach to the electronic structure of C(60) molecule is formulated on the basis of optimized bond orbital model and the stability of the truncated icosahedron structure is examined.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1994-11-30
Volume volume29
Issue issue1
Start Page 15
End Page 22
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002310919
JaLCDOI 10.18926/15461
FullText URL Mem_Fac_Eng_OU_28_2_53.pdf
Author Totsuji, Chieko| Matsubara Takeo| Miyata Satoru|
Abstract One of the best known solid solution of perovskites is the PbTiO(3)-PbZrO(3) system which is usually abbreviated as PZT. In the phase diagram of this system, there is a drastic phase change from tetragonal to rhombohedral at the molar ratio around 50:50. The PZT crystals are widely used as a practical piezoelectric material because of its very strong piezoelectric effect near this morphotropic phase boundary. We try to explain this anomaly in piezoelectric constant by a phenomenological theory.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1994-03-15
Volume volume28
Issue issue2
Start Page 53
End Page 58
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307223
JaLCDOI 10.18926/15440
FullText URL Mem_Fac_Eng_OU_28_1_71.pdf
Author Nishigaki, Makoto| Sudinda Teddy| Hishiya Tomoyuki| Kohno, Iichiro|
Abstract In this paper, method of Eulerian Lagrangian numerical analysis is used to described Advection-Dispersion phenomena. The influence of concentration to the density of fluid is considered. A laboratory model of a two dimensional confined aquifer containing an isotropic, homogeneous porous medium (Hosokawa et.al 1989) was used to validate the applicability of Advection-Dispersion of numerical analysis with steady and unsteady state condition [1].
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1993-11-30
Volume volume28
Issue issue1
Start Page 71
End Page 85
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307975