Research Field of Sakai-Izumi Lab.

1. Research Field of Sakai-Izumi Lab. 4. Micro-Nano Mechanics • Molecular Dynamics for Semiconductor Processes • Dislocation Dynamics for Semiconductor Devices 1. Risk & Reliability 2. Life Cycle Assessment • Risk Assessment for Train • Optimization of maintenance • Network-based R6 system • Application to sensitivity analysis in LCA 3. Fracture Mechanics • Fractography • High-Temperature Hardness

2. 1. Risk & Reliability

3. ③ 3200mm ② ① ⑨ ⑧ ⑦ ⑥ ⑤ ④ ③ ② 3200mm ① ⑨ ⑧ ⑦ ⑥ ⑤ ④ Interior Module Design of Rolling Stocks where Introduces Risk Assessment T.Yokoyama, S. Izumi, S. Sakai (2001) We attach importance to the decision-making performance in risk assessment. It is investigated to apply the risk assessment in the design stage of railroad train. Specifically, the design of ceiling-shelf module is considered. By introducing the risk evaluation, not only the evaluation of function of single part but also the total performance for safety can easily be treated. After the formulation of risk assessment was stated, the application for several decision-makings in ceiling-shelf module was shown. Risk Assessment Initial model with regular interval fastening positions Improved model with optimized fastening positions

4. C Sensitivity Index Most appropriate point Maintenance Cost ($) A B Most appropriate point B C Unavailability Unavailability Multi-objectiveoptimizationapproach to maintenance of nuclear power plant J. Virulsri, S. Izumi, S. Sakai (2002) • In nuclear power plant, in order to optimize conflicting objectives such as low levels of system unavailability and low costs in maintenance activities of nuclear power plant, the multi-objective optimization is applied. Nevertheless, some areas of the Pareto-solutions may lead to inappropriate optimal solutions because of their high sensitivities. Therefore, the new method of sensitivity analysis for selecting the Pareto optimal solutions is proposed in order to obtain the most suitable set of solutions for the maintenance activities.

5. server R6 system client The development network-based R6 system • The necessity of flaw evaluation system is increasing with a lot of demands in applicable program that is convenient for users to operate. So it is important to share the technique of flaw evaluation all over the world and Java is expected to be a very strong tool to achieve this purpose.We developed R6 system and distributed it by using JavaRMI and XML. (Java) connect R6 method

6. 2. Life Cycle Assessment

7. Formulation of sensitivity analysis in life cycle assessment using a perturbation method S. Sakai, Lu Weizhe, S. Izumi (2001) • A new method for the efficient sensitivity analysis in LCA is proposed. Introduction of a perturbation method to matrix-based life cycle assessment will enable one to evaluate the degree of influence of each element on the total sum of environmental loads. Special emphasis is placed on the advantage that the sensitivity matrix, in which each entity denotes the sensitivity of the corresponding element, is derived as a result of matrix operation. The proposed method is compared with another sensitivity analysis and the validity of current method has been confirmed. Using this formulation, the important elements can be distinguished easily and so the method is expected to be applied to the decision-making process.

8. 3. Fracture Mechanics

9. J. Jiang, S. Sakai (2001) Stereoscopic Fracture AnalysisIt is necessary to clarify the cause of fracture or accident.This research can improve 3-D measuring accuracy and visualize fracture surface in reality. 2 ¼ C r-1Mo Creep-Fatigue fracture surface

10. Characterization of fatigue fracture surface using wavelet transformation K.Yamagiwa(2002) In the fatigue fracture surface, the ratio of the area which the striation covers, namely the striated surface ratio, has been said to be deeply related to DK. Therefore, the striated surface ratio is the important factor for the stress estimation. The wavelet transformation (WT) is well known to be suitable to the local feature characterization. The applicability of WT to the characterization of striated surface ratio is examined. To examine the validity of the method, it was applied to the Cr-Mo fatigue fracture surface. It is evaluated by the method that the non-striated area is 10%, the striated area is 26% and the transition area is 64%. The result is compared with that evaluated from visual observation. The results of the evaluation of the striated and non-striated area show good agreement with the result of the human observation. Wavelet transformation

11. Hardness-temperature curve Hot Hardness RT Hardness The evaluation of the damage of the thermal power plant by using hot hardness test T.Murakami, S. Izumi, S. Sakai (2002) • The thermal power plants play an important role as an electric power supply source in our country. In such a situation, the plants which exceeded the design life increase year after year. So, the establishment of an accurate life prediction method of degradation damage in a state of high temperature components such as boiler and turbine is important. • We evaluate damage of disposal turbine rotor material of the Cr-Mo-V steel by using hot hardness test. More accurate evaluations are realized as compared with room-temperature hardness one.

12. 4. Micro-Nano Mechanics

13. Dislocation Dynamics Simulation T. Miyake, S. Izumi, S. Sakai (2002) In semiconductor devices, it is known that the dislocation causes electrical failures. But observation of dislocation motion in the micro-scale devices is very difficult. Therefore, it is useful for searching the source of dislocation if we can simulate the dislocation movement. Simulation of dislocation annihilation.

14. The development of molecular dynamics potential for an Si-H system and its application to the translationally activated CVD process S. Izumi, S. Sakai (2002) • In order to investigate the reaction probability of silane dissociative adsorption, we developed a new Si-H potential. By using molecular dynamics with our potential, the dependence of the molecular and substrate temperatures on the reaction probability was investigated and was compared the results with the translationally activated process.

15. The Molecular Dynamics Study for the Damage and Etching Properties of Low Energy Ar Ion Implantation S. Izumi, S. Sakai (2001) • Molecular dynamics simulations have been performed for the Ar bombardment to Si surface in order to investigate the damage and etching properties. The dependence of the ion energy, the polar angle of the ion and substrate strain was investigated.

16. Surface energy 1.44±0.03 Amorphous silicon Amorphous silicon S=64 [nm2] Surface stress -0.48±0.06 The interface energy and interface stress of amorphous silicon S. Izumi, S. Hara, S. Sakai (2001) • Surface energy and surface stress is a key parameter for predicting of the intrinsic stress of thin film. We have evaluated the statistical properties of the surface energy and the surface stress of amorphous silicon by using molecular dynamics. For applications in the continuum mechanics, the surface stress can be treated as the initial stress generated in a surface region with a thickness of about 0.4 nm.

17. Brief Presentation

18. Brief Presentation Application of Reliability Engineering to the Field of Life Cycle Assessment The University of Tokyo School of Engineering Shinsuke Sakai

19. Background • Lot of Uncertainty in LCA • Importance of identifying the prioritized elements → sensitivity • all sensitivities for each element must be calculated • conventional evaluation method of sensitivity →consumes much time for the procedure • the mathematical perturbation method combined with matrix-based LCA enables us to perform an efficient sensitivity evaluation

20. Material balance for a Process amount Principle of MLCA Treatment for B.C.

21. Application to sensitivity analysis in LCA Target sensitivity Small variation on Perturbation method • is calculated once

22. Example of steel-making process