Hiroshi Tajima

Site-specificities in the interactions of Cu(II) with aldopentopyranoses in dimethyl sulfoxide

Abstract Interactions of Cu(II) with aldopentoses having different C3 and C4 hydroxy configuration, D-arabinose, D-xylose, and their methyl glycosides, in water-dimethyl sulfoxide (dmso) solutions were studied by 13 C NMR with specific line broadening techniques and electronic and ESR spectrometries. When monosaccharides had the arabinopyranose-type ring configuration, site-specific interaction involving C3 and C4 hydroxy groups was observed in dmso, and Cu(II) was shown to suffer tetragonal distortion upon coordination of monosaccharides. Anomer- and site-specificity of the interaction between monosaccharides and Cu(II) were sensitive to the nature of the solvent.

Modeling, Motion and Vibration Control for Flexible Rotor Supported by Active Magnetic Bearings

This paper proposes a new modeling technique and control system design for flexible rotors using active magnetic bearings (AMB) to pass through many critical speeds and fulfill high-speed rotation. To achieve this purpose, it is necessary to control not only motion but also many modes of bending vibration. For the purpose, an extended reduced order physical model that is able to express simultaneously the motion and bending vibration of the flexible rotor, is proposed. Furthermore, a new controller combined PID with LQ control is adapted to control the flexible rotor. Effectiveness of the proposed modeling and control approach for the flexible rotor is verified through simulations and experiments.Copyright

Modeling Method for Flexible Multibody Systems with Arbitrary Boundary Conditions by Using Extended Reduced-Order Physical Model (1st Report, The Proposal of Modeling Method and Verification of Modeling Accuracy)

This paper proposes a modeling method of an Extended Reduced-Order Physical Model (Extended Model) with arbitrary boundary condition. The Extended Model is proposed to apply to the simultaneous motion and vibration control of elastic structures. The Extended Model consists of some rigid bodies which are called as rigid body elements and stiffness elements. To design rigid body elements, four dynamical conditions are used ; (1) Total mass and Total moments of inertia, (2) Position of center of gravity, (3) Modal mass and Orthogonality, (4) Modal momentum and Modal angular momentum. The (1) - (4) values of a modeling object are needed to identify masses and moments of inertia of rigid body elements. In the case of that an elastic body has free boundary conditions, the values of the Modal momentum and the Modal angular momentum are zero. On the other hand, in the case of that an elastic body has general boundary conditions, these values are not zero and needed to be identified by any means. However, it is not always any to identify these values. Therefore, a novel formulation to identify mass and inertia matrices is presented that utilizes dynamical conditions for the original object subjected to free boundary conditions. The effectiveness of the presented formulation is examined by using a simple beam. Numerical analysis is carried out and the effectiveness of the presented modeling procedure is verified.

Stability and Controllability Analysis of a Motorcycle

In this paper, we present a linearized system of a motorcycle and its stability and controllability analysis is done. The equation of motion for the motorcycle have been obtained using the multi-body dynamics analysis assuming that the motorcycle consists of four rigid parts with nine degrees of freedom. In this model the cross-sectional shape of the tire was described as a half circle and its deformation has been taken into account. By carrying out simulations it has been verified that the responses to the front-steering impulsive torque are in good agreement with those of a marketed dynamics analysis software. Two inputs of the steering torque and the driving torque of the rear wheel are taken into consideration. By using the balanced realization method the gramians of the linearized system are obtained to examine the reduced-order model with the frequency responses and the impulsive responses.Copyright

Toward the Improvement of Education in Mechanics

Two catch phrases of my half year lectures of Mechanics, which are given at two Universities, are as follows: “Three dimensions from the beginning”, and “Various methods to derive the equations of motion”. We often do not have enough time to teach kinematics and dynamics from two-dimensional matters first and then proceed to three dimensions. In many cases three-dimensional subjects are considered to be something advanced, or something which two-dimensional methods can be applied to. As a result we often lose chances to teach three-dimensional matters. I think there are few universities that give clear and firm teaching of three dimensional kinematics and dynamics. Many teachers often escape from three-dimensional discussions saying two dimensions are fundamental. I feel that there are very few teachings and discussions in Japan on the methods for deriving the equations of motion. There are many teachers who tell the importance of the equations of motion, but there are few who can discuss various methods to derive them. Discussion and Recognition of various methods not only broaden the application ability but also give clearer understanding in mechanics itself that will connect to the creation of new methodology. My lecture is a direct answer to these points, and my five year experience gives me more confidence in the importance of them. My recent effort is to get more chances to teach it not only within the universities, but also outside of them, getting more sympathetic people. At present I feel that my lecture will surely give some certain effects to the engineering education in mechanics in Japan.Copyright

Technique to Handle Local Constraints in Multibody Dynamics

Sometimes we have a system that can be expressed basically by independent variables, with some redundant variable groups to decide only small parts of the system respectively. If the constrains of these redundant variables in each group are not coupled with each other, namely these are no common variables, we call them as local constraints. Example of local constrains are Euler parameter constraint and constrains of link mechanism of car suspension system. The necessity of redundant variables can also be limited for position level. Within the simple nonholonomic system we can always select the appropriate independent velocities to express the other velocity level variables. If the system has only local constraints, it is inefficient to use the typical DAE formulation, which handled all the constraints simultaneously. The technique we explain in this paper has advantage in calculation time and also in the sense of constrain stabilization. This paper gives a basic idea of the technique and its general formulation. Also three examples are explained which we used to confirm the effectiveness of the technique. We got a good result of constrains stabilization. More detailed examination about the calculation time and the constraint stabilization is planned in near future before we proceed to construct a simulation program of complex elastic vehicle model.Copyright