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2007

Journal of Marine Science and Technology

Articles 1 - 7 of 7

Full-Text Articles in Mechanical Engineering

Study On The Characteristics Of Tiller Blade Shapes By Spray-Welding Hardening, Jain-Song Ju Jun 2007

Study On The Characteristics Of Tiller Blade Shapes By Spray-Welding Hardening, Jain-Song Ju

Journal of Marine Science and Technology

This study attempts to validate and analyze the mathematical models of the plowing dynamics and trajectory curve for tiller and cultivation blades of a rotary cultivator. Both blades are extensively used in Taiwan. The blade must be protected from intertwisting to ensure high efficiency and uniform resistance of the plow to soil. Theoretical and calculated cutting angles are found to be 85.88° and 84.28°, respectively, while the theoretical and calculated edge-curve angles are 59.70° and 58.31°. The present data confirmed that the tiller blades developed by local companies are suitable for the plowing environment in Taiwan. In order to reduce …

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Modeling And Control Of A New 1/4t Servo-Hydraulic Vehicle Active Suspension System, Jyh-Chyang Renn, Tsung-Han Wu Jun 2007

Modeling And Control Of A New 1/4t Servo-Hydraulic Vehicle Active Suspension System, Jyh-Chyang Renn, Tsung-Han Wu

Journal of Marine Science and Technology

Nowadays, the active suspension is the key technology for vehicles to achieve both ride comfort and control performance. In this paper, a new 1/4T servo-hydraulic vehicle active suspension system is developed and two control schemes are utilized. The first one is a conventional PID controller obtained from Ziegler-Nichols method and the second one is the neural network controller. Though these two controllers are quite simple and not new, it is still worth mentioning that this paper emphasizes on the engineering aspects including the design of a servo-hydraulic test rig, the implementation technology of the controllers and the subsequent experimental study. …

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Piv Measurements Of Exit Flow Field Of Centrifugal Fans With Conditional Sampling, Shun-Chang Yen, Jung-Hsuan Liu Jun 2007

Piv Measurements Of Exit Flow Field Of Centrifugal Fans With Conditional Sampling, Shun-Chang Yen, Jung-Hsuan Liu

Journal of Marine Science and Technology

In this research, we have experimented with two centrifugal fans with the same geometrical configuration. These two fans are designed to rotate at different speeds driven with the same voltage. The Particle Image Velocimetry (PIV) method is applied to measure the instantaneous flow fields at the near-exit region. The AMCA 210 wind tunnel is used to find the efficiency and the performance coefficients. The velocity vectors, streamlines, vorticity contours, velocity distributions, flow rate, and performances are also presented and discussed. We find that higher rotation speed yields better efficiency.

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Stochastic Chaotic Motion Of Ships In Beam Seas, Li-Qin Liu, You-Gang Tang, Hong-Xia Li Apr 2007

Stochastic Chaotic Motion Of Ships In Beam Seas, Li-Qin Liu, You-Gang Tang, Hong-Xia Li

Journal of Marine Science and Technology

The stochastic chaotic motion and the threshold intensity of the external excitation force for onset of chaos of the ships in random beam waves are studied by the nonlinear stochastic dynamics theory. The random differential equation of ships’ rolling motion is established with considering the nonlinear damping, nonlinear restoring moment and the white noise wave excitation. The random Melnikov mean-square criterion is used to determine the threshold intensity for onset of chaos. The probability density function of the rolling response is calculated through solving the stochastic differential equations by applying the path integral method in the chaotic region. It is …

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Study Of The Flow Field And Scalar Transport Of Indoor Ventilating Space Under The Impact Of Coanda Vortex, Je-Ee Ho, Hong-Tsu Young Apr 2007

Study Of The Flow Field And Scalar Transport Of Indoor Ventilating Space Under The Impact Of Coanda Vortex, Je-Ee Ho, Hong-Tsu Young

Journal of Marine Science and Technology

The vortex in the flow field will isolate the space to further reduce the indoor air exchange and convective efficiency. The Coanda vortex accompanied by the inlet jet usually has the most active effect on the flow field. Both its location and scalar size which are primary determined by the strength of the injected flow and the arrangement of inlet; outlet will deeply affect the air-exchange volume, even reduce the available ventilation space. A 2-D turbulent model with SIMPLE method is set up to simulate the air motion of indoors; it can easily describe the working of Coanda vortex in …

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Optimal Allocation Of Heat Transfer Area For A Refrigeration Plant, Tong-Bou Chang Feb 2007

Optimal Allocation Of Heat Transfer Area For A Refrigeration Plant, Tong-Bou Chang

Journal of Marine Science and Technology

For an internally reversible refrigerant plant, Bejan proposed an optimal way of dividing the area ratio of heat transfer for the hot end and cold end heat exchangers. In the present study, an optimal design of a refrigeration plant has been developed by considering both the external and internal irreversibilities. The internal irreversibility is modeled by a heat bypass which represents the actual internal heat leak and the friction losses due to mechanism movement. A more general formulation than previous study of optimal area-ratio is obtained in this study. For the case of no internal irreversibility, this formulation is exactly …

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The Relationship Between The Location Of Obstacle And Indoor Particle Deposition, Je-Ee Ho, Hong T. Young Feb 2007

The Relationship Between The Location Of Obstacle And Indoor Particle Deposition, Je-Ee Ho, Hong T. Young

Journal of Marine Science and Technology

An appropriate ventilation system design not only increases the indoor ventilation effect but effectively improves the particle concentration distribution. The locations of indoor furniture are used to analyze the indoor airflow and particle distribution by numerical skill in this study. Also, a 45 cm × 45 cm × 45 cm chamber is setup as experiment apparatus which is made by acrylic resin board with 16 holes connected to supply air flow. In order to simulate the furniture effect, some wooden blocks are located at the chamber. The temperature and humidity sensors are connected to the data acquisition system with a …

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