Active vibration control of a flexible beam subjected to arbitrary, unmeasurable disturbance forces is investigated in this paper. The concept of independent modal space control is adopted. Both the feedforward and feedback control is implemented here to reduce the beam vibration. Because of the existence of the disturbance forces, the feedforward control is applied by employing the idea of force cancellation. A modal space disturbance force observer is then established in this paper to observe the disturbance modal forces for the feedforward control. For obtaining the feedforward and feedback control gains with the optimal sense, the nearly optimal control law is derived, where the modal disturbance forces are regarded as additional states. The vibration control performances and the asymptotic properties of the control law are discussed.

This study develops a kinematic/kinetic model to evaluate the effect of different handle angles on wrist loading during lifting task. An imaged-based motion analysis system is used to study the movement pattern, force and moment of the wrist joint among nine different handle angles. Six CCD cameras were used to record 3-D trajectories of limb-mounted markers based on the laboratory coordination system as defined by an 8-marker cube. Euler angles are used to describe the orientation of a distal segment reference frame relative to a proximal segment reference frame. Each segment of the upper extremities is regarded as a uniform rigid body with six degrees of freedom. The resultant loading of the wrist joints was determined using an inverse dynamic procedure.

This study indicates that tool handles can be designed or selected to reduce manual loading and the potential for injury during tool use. The mean curve of joint force and moment provided consultations and understandings of the wrist loading during lifting task. In this study, handles that kept the wrist joints in a dorsiflexed and radial deviated position, showed significant reduction in stresses around the surrounding soft tissue.

This work presents a rigorous three-dimensional finite element procedure to analyze belt transmission systems. The frictional contact behavior between the belt and the pulley, which accounts for the power loss of the system and the wear of the belt, is investigated in detail. In addition to adopting the transformation matrix to satisfy the geometric conditions on the contact surfaces, the proposed procedure also uses the modified elements with incremental Wilson displacement modes to improve the accuracy due to bending at the end zones of the contact area for the belt. To demonstrate the accuracy and feasibility of the proposed procedure, the analyses for flat and V belt drives are carried out. Excellent correlations between the calculated results and referenced theoretical/experimental solutions are found. The influences of friction coefficients on the deformation, normal and tangential contact forces on the contact surfaces are studied as well. Those will be helpful for the estimation of wear properties and operation efficiency for belt transmission systems.

To study the effect of lubrication on the performance and dynamic loads of scroll compressors, a theoretical model is proposed in this paper. The model includes both thermal and dynamic analyses in which the lubrication theory is emphasized in particular. A computer simulation program is written accordingly, and the effects of different design parameters including oil flow rate, injection position, injection temperature and rotating speed are investigated. The output variables such as gas force, contact force, contact moment and thermal performance of the compressor are obtained. Some of the results are compared with experimentally measured data, and good agreements are found between the simulation results and the measured data. The applicability of the simulation program is thus verified.Analytical results from running this program can provide us valuable information on the design improvement of a scroll compressor.

During the past several decades, nearly symmetrical tidal appearances, both the time of high water elevation and the tidal range, were noted along the western coast of Taiwan. Research corresponding to anomalous amplifications of tidal range have been well studied by Lin, et al. [1,2], but the particular symmetrical tidal appearance of high water time has not yet been clarified. In this paper, we firstly apply a harmonic analysis to tidal data compiling. Based on the results, the important symmetric appearances of high water time and tidal range can be located. Emphasis is given on the investigation of symmetrical distribution of high water time by superposing two progressive waves that interfere on a topographic shelf with specific width. A conceptual configuration of co-oscillating standing tides is proposed to demonstrate the symmetrical tidal range distributing in the space domain and oscillating in the time domain.

A three-dimensional Navior-Stokes analyzer based on control volume method is developed to simulate the complex flow field within a turbomachinery. With VKI-CT2 turbine blade as the test model, numerical results are compared with experimented data and shows the existence of separation-transition bubble and the interaction of shock with turbulent boundary layer flow. The governing Navier-Stokes equations are solved by an improved numerical method that uses an upwind flux-difference split scheme for spatial descretization and an explicit optimally smoothing multi-stage scheme for time integration. Turbulent stresses are approximated by modifying Baldwin-Lomax algebraic, k-ε, R-k-ε and RNG k-ε turbulence models. According to the results of this research, this analyzer can indeed effectively modulate and simulate the aerodynamic characteristic of the transonic turbine rotor near the endwall.