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Journal of Marine Science and Technology–Taiwan

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Articles 1171 - 1200 of 1299

Full-Text Articles in Engineering

Effects Of Earthquake Excitation On The Strength Properties Of Newly Poured Concrete, Jen-Hui Su, Tsong Yen Feb 2004

Effects Of Earthquake Excitation On The Strength Properties Of Newly Poured Concrete, Jen-Hui Su, Tsong Yen

Journal of Marine Science and Technology–Taiwan

This study examines the 28-day strength properties of concrete under shaking, such as from an earthquake, during its strength development period. With a concrete strength of 20.59 MPa (3,000 psi), groups of concrete cylinders were made and tested on a shaking table. The peak value of ground acceleration (PGA) level of the simulated earthquake and the cylinder age are the two variables considered. The test results are as follows. If the concrete is older than three days, the earthquake excitation will not significantly reduce its 28-day strength. At younger than two days, earthquake excitation will reduce the strength of the …

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Investigation Of Seakeeping Characteristics Of High-Speed Catamarans In Waves, Chih-Chung Fang, Hoi-Sang Chan Feb 2004

Investigation Of Seakeeping Characteristics Of High-Speed Catamarans In Waves, Chih-Chung Fang, Hoi-Sang Chan

Journal of Marine Science and Technology–Taiwan

This paper presents the motion characteristics for high-speed catamarans travelling in waves. Two mathematical models, threedimensional translating-pulsating source distribution technique and three-dimensional pulsating source distribution technique, are used for predicting the motions of the wave-piercing catamaran in oblique waves. The comparison between numerical predictions and experimental data carried out in SSPA shows a good agreement except the one around the resonance regions of pitch motion. It may be due to the nonlinear effects of centre bow with large pitch motions in waves. The phase angles show some scatters in the high frequencies region at stern waves. The dynamic motions of …

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Laterial Performance Of Drilled Shaft Considering Nonlinear Soil And Structure Material Behavior, Chao-Kuang Hsueh, San-Shyan Lin, Shuh-Gi Chern Feb 2004

Laterial Performance Of Drilled Shaft Considering Nonlinear Soil And Structure Material Behavior, Chao-Kuang Hsueh, San-Shyan Lin, Shuh-Gi Chern

Journal of Marine Science and Technology–Taiwan

In addition to nonlinear soil behavior has been assumed in conventional analytical method, performance of the laterally loaded drilled-shaft is also strongly influenced by possible concrete cracking, steel yielding, and shaft/soil separation and interaction. However, these factors are often neglected in the most of available methods and studied results. The main purpose of this paper is to investigate the importance of the above-mentioned effects on lateral performance of drilled reinforced-concrete shaft. The finite element code, ABAQUS, which is available in the three-dimensional analysis is adopted for taking into account the nonlinearity in shaft and soil materials, pilesoil interaction and nonlinear …

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Unveiling The Crucial Role Of Impact Nergy Loss For So-Called Incompressible Fluid Flow, Jiunn-Shean Chiang, Shu-Hao Chuang, Hsing-Juin Lee Feb 2004

Unveiling The Crucial Role Of Impact Nergy Loss For So-Called Incompressible Fluid Flow, Jiunn-Shean Chiang, Shu-Hao Chuang, Hsing-Juin Lee

Journal of Marine Science and Technology–Taiwan

Experiments show that pipe flows with large expansion angle and area ratio always accompany with significant amount of energy loss, actually energy loss ratios over 70% of incoming flow kinetic energy are commonplace. It is generally believed that all the energy loss is entirely due to viscous dissipation effect. In this paper, several interesting demonstrations have been given to prove the existence and importance of impact energy loss. Literally, impact energy loss is usually more important than viscous energy loss in many cases. In fact, the pipe expansion flow can be configured as high-speed flow ramming into low-speed flow and …

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Selection Of Area Suitable For Performing Partial-Depth Repair Of Corner Damage Of Concrete Paving Slab Under Wheel Load, Chau Lee, Xin-Hua Huang, Jhao-Bin Lin Feb 2004

Selection Of Area Suitable For Performing Partial-Depth Repair Of Corner Damage Of Concrete Paving Slab Under Wheel Load, Chau Lee, Xin-Hua Huang, Jhao-Bin Lin

Journal of Marine Science and Technology–Taiwan

This study reveals the characteristics of using different repair materials and different repair outline designs for the partial-depth repair of the damage to corners of concrete paving slabs under wheel load. 3D finite element models were used to study how the changes to the outlines of the repaired area affect the maximum-stress and lowstress proportions in concrete elements that are attached to repaired interface when different repairing materials are used. The results indicate that the maximum stress increased but the proportion of lowstress shrank as the repaired area became larger. When cementitious repair materials were used, the depth of a …

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Thermal Analysis Of Welding On Aluminum Plates, Rong-Hua Yeh, Shih-Pin Liaw, Hong-Bin Yu Dec 2003

Thermal Analysis Of Welding On Aluminum Plates, Rong-Hua Yeh, Shih-Pin Liaw, Hong-Bin Yu

Journal of Marine Science and Technology–Taiwan

This study investigated the temperature distribution of aluminum plates welded by gas tungsten arc. The heat of fusion, the size and distribution of heat source, the travel speed, the heat conduction in the welding direction and the surface heat loss during welding were considered. A numerical scheme was developed to solve the threedimensional problem. With the help of a mathematical model, the effect of welding parameters such as heat input of the weld, preheating of the workpiece and moving velocity of heat source on weld penetration in moderately thick plates were discussed. The steady-state temperature profiles of the welded plate …

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A Novel Approach To Determine The Astronomical Vessel Position, Chih-Li Chen, Tien-Pen Hsu, Jiang-Ren Chang Dec 2003

A Novel Approach To Determine The Astronomical Vessel Position, Chih-Li Chen, Tien-Pen Hsu, Jiang-Ren Chang

Journal of Marine Science and Technology–Taiwan

In this paper, a novel approach based on the trigonometric equation solving technique is developed to solve the classical problem of celestial navigation. It is shown that this approach, namely, the simultaneous equal-altitude equations method (SEEM), can directly calculate the astronomical vessel position (AVP) without an additional graphical procedure. It is also found that the SEEM is not only simpler than the matrix method but is also more straightforward as compared with the spherical triangle method. In addition, aimed at the drawbacks of the intercept method, an improved approach with the new computation procedure is presented to plot the celestial …

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Cost Comparison Of Straddle Carrier Direct And Relay Systems In Container Terminals, Wen-Chih Huang, Chin-Yuan Chu Dec 2003

Cost Comparison Of Straddle Carrier Direct And Relay Systems In Container Terminals, Wen-Chih Huang, Chin-Yuan Chu

Journal of Marine Science and Technology–Taiwan

The main characteristics of straddle carrier direct system and straddle carrier relay system are stated and factors affecting the economics of this two handling systems are also studied. A cost function model is proposed to make the comparison. It includes land cost, equipment cost, transportation cost between quayside and storage yard, annual throughput, handling efficiency, labor cost and their constituent factors. A "handling cost comparison indicator" (RD) is also submitted to determine the preferred system. For RD > 1 scenario, straddle carrier direct system is preferred, and on the contrary, straddle carrier relay system is preferred, if RD < 1.

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Computer-Aided Optimal Design Of A Single-Chamber Muffler With Side Inlet/Outlet Under Space Constraints, Long-Jyi Yeh, Ying-Chun Chang, Min-Chie Chiu, Gaung-Jer Lay Dec 2003

Computer-Aided Optimal Design Of A Single-Chamber Muffler With Side Inlet/Outlet Under Space Constraints, Long-Jyi Yeh, Ying-Chun Chang, Min-Chie Chiu, Gaung-Jer Lay

Journal of Marine Science and Technology–Taiwan

Whilst the muffler dimension is often limited inside a building or machine room, the consideration of maximal sound transmission loss (STL) under space constraints becomes important and essential to the field of acoustics. In this paper, the optimal design of a singlechamber muffler with side inlet/outlet is comprehensively presented. Both the graphic analysis and the computer-aided numerical assessments are also fully described in this study. With the computer graphic analysis on sensitivity, one set of design data is derived primarily, and the numerical searching algorithm of iteration technique and the initial design data are then carried out. These results are …

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A Normalization Scheme Of Bidirectional Reflectances And Normalized Vegetation Indices For Short-Term Multi-Angular Spot Satellite Images, Chien-Hui Liu Dec 2003

A Normalization Scheme Of Bidirectional Reflectances And Normalized Vegetation Indices For Short-Term Multi-Angular Spot Satellite Images, Chien-Hui Liu

Journal of Marine Science and Technology–Taiwan

Though the view angle range of SPOT HRV is smaller as compared to those of NOAA AVHRR, EOS MODIS/MISR and ADEOS POLDER, numerous researchers had showed significant bi-directional effect of ground reflectance for decades. Currently, there's no existing normalization method of bidirectional reflectances for multitemporal SPOT images. In this study, a normalization scheme for multi-angular SPOT data is proposed. This scheme will correct both atmospheric and bidirectional effect for short-term multi-temporal SPOT data. Five SPOT images scanned within twelve days are used. The results show that the variation of trees reflectance to viewing zenith angle is very significant. The proposed …

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A Novel Earplug System For Filtering Out Dental Noise, Jiang-Ren Chang, Huan-Kun Cheng, Sheng-Yang Lee, Mingsian R. Bai, Rong-I Lean Dec 2003

A Novel Earplug System For Filtering Out Dental Noise, Jiang-Ren Chang, Huan-Kun Cheng, Sheng-Yang Lee, Mingsian R. Bai, Rong-I Lean

Journal of Marine Science and Technology–Taiwan

Undergoing dental treatment is usually a very unpleasant experience for people who have toothaches, especially when they are hurting and there exists some intolerable mechanical noise. To reduce the noise and promote the work efficiency of dentists, a new noisefiltering earplug system with optional music was developed to filter out dental machine noise; if necessary, it can also be adopted as a solution to reduce pain and anxiety of patients during treatments. Furthermore, it can also simultaneously serve as a communication tool between the patient and dentist. In this study, various kinds of noises were initially collected through an off-line …

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A Simplified Approach To Estimate The Ultimate Longitudinal Strength Of Ship Hull, Hsin-Chuan Kuo, Jiang-Ren Chang Sep 2003

A Simplified Approach To Estimate The Ultimate Longitudinal Strength Of Ship Hull, Hsin-Chuan Kuo, Jiang-Ren Chang

Journal of Marine Science and Technology–Taiwan

In this paper, the calculation of the ultimate longitudinal strength of the ship hull is revisited. A simplified approach dealing with the longitudinal ultimate strength of ship hull has been developed and an effective numerical program is implemented based on the individual components of ship structures. It is, then, possible to find the ultimate strength of the whole ship structure by evaluating those individual components. Comparisons of numerical results from the proposed approach and published literatures are conducted for further validation. Since relative errors of calculations of the current approach to the literature with respect to the experimental data are …

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An Analytical Model For Deflection Of Laterally Loaded Piles, Jen-Cheng Liao, San-Shyan Lin Sep 2003

An Analytical Model For Deflection Of Laterally Loaded Piles, Jen-Cheng Liao, San-Shyan Lin

Journal of Marine Science and Technology–Taiwan

Load-deflection responses of laterally loaded piles are often obtained via in-situ lateral pile load tests. Problems of such tests are the difficulties occurring during data interpretation. In an effort to develop an efficient analytical method for analyzing deformation data of lateral loaded piles, an analytical model is proposed based on energy conservation of pile-soil system. The proposed analytical model not only provides a direct solution of the pile deflection function, but also has less need of complicated subsurface soil properties. In this paper, the authors present the theory and analytical model development of the proposed method. Two real cases are …

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Model-Based Fuzzy Modeling And Control For Autonomous Underwater Vehicles In The Horizontal Plane, Wen-Jer Chang, Wei Chang, Hsien-Hsueh Liu Sep 2003

Model-Based Fuzzy Modeling And Control For Autonomous Underwater Vehicles In The Horizontal Plane, Wen-Jer Chang, Wei Chang, Hsien-Hsueh Liu

Journal of Marine Science and Technology–Taiwan

In this paper, the modeling and control of nonlinear Autonomous Underwater Vehicle (AUV) system is considered by using a TakagiSugeno (T − S) type fuzzy model. Applying the AUV T − S fuzzy model, one can develop a model-based fuzzy controller design utilizing the concept of Parallel Distributed Compensation (PDC). The main idea of the controller design approach is to derive each control rule so as to compensate each rule of a fuzzy system. The design procedure is conceptually simple and natural. Finally, the responses of states of AUV dynamic real system and AUV dynamic T − S fuzzy model …

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A Practical Experience About Dynamic Performance And Stability Improvement Of Synchronous Generators, Chi-Jui Wu, Yung-Sung Chuang Sep 2003

A Practical Experience About Dynamic Performance And Stability Improvement Of Synchronous Generators, Chi-Jui Wu, Yung-Sung Chuang

Journal of Marine Science and Technology–Taiwan

This paper describes the practical experiences about the no-load dynamic performance test, parameter identification, and tuning of static excitation systems (SESs) of the synchronous generators in the Tong-Shiao Generation Station of the Taiwan Power System. The dynamic stability of under-load generators has also been improved. The hardware circuits of SESs had been modified. This caused the detuning of parameter values, so that the generators did not have enough ability to sustain voltage fluctuation disturbances. Several SESs had been preliminarily retuned according to the results from simple field tests. However, step signal responses in field tests revealed that the characteristics of …

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Experimental Study Of The Rheological Behaviors Of Fresh Concrete, Mortar, And Clay Grout, Cho-Liang Tsai, Yun Du, Yi-Shiun Tsai Sep 2003

Experimental Study Of The Rheological Behaviors Of Fresh Concrete, Mortar, And Clay Grout, Cho-Liang Tsai, Yun Du, Yi-Shiun Tsai

Journal of Marine Science and Technology–Taiwan

Most studies assume that fresh concrete is a Bingham fluid, but few studies precisely measure its Bingham constants, shear yield stress and viscosity, especially for normal fresh concrete. In stead of using commercial viscometer, this work developed a new experimental method and analytical procedure, based on the Stokes’ flow, for characterizing rheological properties of fluids. The experimental method developed here involved dragging a sphere submerged in the specimen fluid at a constant speed and measuring the resistance. Rheological properties of the specimen fluid can be calculated from the theoretical function correlating the drag velocity, drag force, and rheological properties of …

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Magneto-Hydrodynamic Squeeze Film Characteristics Between A Sphere And A Plane Surface, Tsu-Liang Chou, Jen-Wen Lai, Jaw-Ren Lin Sep 2003

Magneto-Hydrodynamic Squeeze Film Characteristics Between A Sphere And A Plane Surface, Tsu-Liang Chou, Jen-Wen Lai, Jaw-Ren Lin

Journal of Marine Science and Technology–Taiwan

Based upon the thin-film magneto-hydrodynamic (MHD) theory, this paper analyzes the squeeze-film characteristics between a sphere and plane surface lubricated with an electrically conducting fluid in the presence of a transverse magnetic field. The MHD Reynolds-type equation governing the squeeze-film pressure is derived using the continuity equation and the magneto-hydrodynamic motion equations. A closed-form solution for the squeezing film pressure is obtained, and applied to predict the MHD squeeze-film characteristics. According to the results obtained, the presence of externally applied magnetic fields signifies an enhancement in the squeeze-film pressure. On the whole, the magnetic-field effects characterized by the Hartmann number …

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Comparison Matrix Method And Its Applications To Damage Evaluation For Existing Reinforced Concrete Bridges, Ming-Te Liang, Chin-Ming Lin, Chi-Jang Yeh Jun 2003

Comparison Matrix Method And Its Applications To Damage Evaluation For Existing Reinforced Concrete Bridges, Ming-Te Liang, Chin-Ming Lin, Chi-Jang Yeh

Journal of Marine Science and Technology–Taiwan

The main purpose of this paper was adopting the comparison matrix method, which is generated from both the analytic hierarchy process and the principle of moment equilibrium, to assess the repair order of existing reinforced concrete (RC) bridges. Ten existing RC bridges in Keelung, Taiwan, were given as an illustrative example. In order to verify the feasibility and reliability of the proposed method, the D (Degree) E (Extend) R (Relevancy) evaluation method, which is now widely used to evaluate the damage grade for existing RC bridges in Taiwan, was also applied to assessing the same ten existing RC bridges. The …

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Design Of Fuzzy Nonlinear Robust Compensator And Its Application On Submarines, Cheng-Neng Hwang, Joe- Ming Yang Jun 2003

Design Of Fuzzy Nonlinear Robust Compensator And Its Application On Submarines, Cheng-Neng Hwang, Joe- Ming Yang

Journal of Marine Science and Technology–Taiwan

A robust nonlinear composite controller, which is simple in structure and has the characteristics of good tracking performance and guaranteed system stability, is designed in this study. A pre-compensator is proposed to eliminate uncertainties or disturbances so that the tracking error is bounded in a pre-specified ball. The composite control law proposed in this study guarantees system tracking precision and stability by the aid of a third-order differential equation that has been derived in this research. The control parameters in the proposed controller can be adjusted systematically. For unknown serious variation in system surrounding, a composite control law with fuzzy-type …

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Parameter Analysis And Optimization Of Electrolytic In-Process Dressing Grinding On Ceramics, Chang-Pin Lin, Kuei-Miao Hsiao, Chun-Chung Wu Jun 2003

Parameter Analysis And Optimization Of Electrolytic In-Process Dressing Grinding On Ceramics, Chang-Pin Lin, Kuei-Miao Hsiao, Chun-Chung Wu

Journal of Marine Science and Technology–Taiwan

Ceramic materials have been studied and used in considerable industrial applications due to their high hardness and strength at high temperature and extreme wear resistance. However, the machining costs of these materials may reach as high as 90% of their total component costs and the grinding of these materials are much more susceptible to surface damage as compared to metals. Electrolytic InProcess Dressing (ELID) grinding can be used to machine hard and brittle materials, such as aluminum oxide (Al2O3), that are difficult to be machined by conventional grinding processes to achieve high surface quality and high material removal rate. The …

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Study Of Yuen-Lin Liquefaction During Chi-Chi Earthquake, Shuhgi Chern, Juei-Hsing Tsai, Ching-Yinn Lee Jun 2003

Study Of Yuen-Lin Liquefaction During Chi-Chi Earthquake, Shuhgi Chern, Juei-Hsing Tsai, Ching-Yinn Lee

Journal of Marine Science and Technology–Taiwan

Extensive subsurface exploration of Yuen-Lin liquefaction area was conducted by National Science Council after Chi-Chi earthquakes. Data obtained from the subsurface exploration in Yuen-Lin area had been studied and three widely used liquefaction evaluation methods, i.e. Seed method, T-Y method and JRA method, were employed for liquefaction evaluation. The depth of the liquefied soil layer was also identified by comparison of grain size distribution curve of explored sample and field data. Iwasaki's liquefaction potential index was further used to analyze liquefaction induced risk of damage. Finally, Multiple Additive Decision Making method (MADM) was applied to determine the suitability of the …

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Dynamics Of Asymmetric Nonlinear Vibration Absorber, Chiou-Fong Chung, Chiang-Nan Chang Mar 2003

Dynamics Of Asymmetric Nonlinear Vibration Absorber, Chiou-Fong Chung, Chiang-Nan Chang

Journal of Marine Science and Technology–Taiwan

A dynamics of stability and bifurcation analysis of an asymmetrically nonlinear absorber system that contains a main part and a nonlinear spring is proposed. For this study, the analytical works on this nonlinear vibration absorber were performed by the harmonic balance method and the Floquet theory. Dynamic phenomena due to changing of periodic excitation are analyzed. The investigation fulfils that the bifurcation sequences illustrate completely the complex phenomena of system dynamics. Furthermore, this study show that the primary bifurcation orbit coexist with orbit of the secondary responses via a saddle-node bifurcation in a specific period excitation range. The results demonstrate …

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Mathematical Modeling And Applications For Concrete Carbonation, Ming-Te Liang, Shieng-Min Lin Mar 2003

Mathematical Modeling And Applications For Concrete Carbonation, Ming-Te Liang, Shieng-Min Lin

Journal of Marine Science and Technology–Taiwan

A new concept, carbon dioxide (CO2) transport in concrete, is proposed in this paper to describe solute-transport processes. Using this concept, a new one-dimensional mathematical model was developed to describe the transport phenomena of carbon dioxide in concrete structures. By treating transport phenomena as a concrete carbonation process, a one-dimensional linear partial differential equation was derived based on the principle of mass balance and convective-dispersive equation and was found the analytical solution by the separation of variables and the Laplace transform methods combined with some substitution approaches. The concrete carbonation numerical results were determined using parameters, such as the diffusion …

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Study On Vortex-Excited Nonlinear Vibration Of Casing Pipes In Wave-Current, You-Gang Tang, Jian-Qin Min, Hong-Yu Zheng, Jia-Yang Gu Mar 2003

Study On Vortex-Excited Nonlinear Vibration Of Casing Pipes In Wave-Current, You-Gang Tang, Jian-Qin Min, Hong-Yu Zheng, Jia-Yang Gu

Journal of Marine Science and Technology–Taiwan

The vortex-induced nonlinear vibration of casing pipes in the deep water is studied considering the loads of current and combined wave-current. The vortex-induced vibration equation of a casing pipe is set up with considering the beam mode and Morison's nonlinear fluid damp as well as the vortex-excited loads. The approach of calculating vortex-excited nonlinear vibration by Galerkin's method is proposed. The natural vibration characteristics and the vortexexcited vibration response of 170m long casing pipe in the 160m depth of water are investigated, the resonance induced by wave and the resonance under combined wave-current were investigated, which is shown that the …

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Data Compression Applied To Electric Power Quality Tracking Of Arc Furnace Load, Chi-Jui Wu, Tsu-Hsun Fu Mar 2003

Data Compression Applied To Electric Power Quality Tracking Of Arc Furnace Load, Chi-Jui Wu, Tsu-Hsun Fu

Journal of Marine Science and Technology–Taiwan

The data compression techniques are used to enhance the storage capability of electric power quality instruments in monitoring distorted waveforms of electric arc furnaces. Both voltage flicker in voltage waveforms and harmonic components in current waveforms are major disturbances. The compression approaches by multiresolution analysis developed from the discrete wavelet transform with threshold coding and vector quantization coding are compared. The results from spectrum analysis show high compression ratios while keep low information loss. The error levels between original and reconstructed waveforms are discussed. Field measured waveforms from arc furnace loads are used to show the goodness of the data …

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Study On The Vibration Reduction Of The Double Pistons Hydraulic Engine Mount, You-Gang Tang, Hong-Yu Zheng, Jia-Yang Gu, Da-Ning Jiang Mar 2003

Study On The Vibration Reduction Of The Double Pistons Hydraulic Engine Mount, You-Gang Tang, Hong-Yu Zheng, Jia-Yang Gu, Da-Ning Jiang

Journal of Marine Science and Technology–Taiwan

A novelty style metal hydraulic engine mount (HEM) is developed. The HEM designed in this paper consists of hydraulic cylinder, bar, two pistons and the spring on the bottom. The mechanical model and the dynamic equations are set up by considering kinematics and continuous of fluid, and the analytical method for dynamic behavior including dynamic stiffness and transfer function of HEM are suggested herein. The dynamic characteristics of HEM are investigated. It is shown that the HEM proposed herein can be employed in the practical engineering for vibration reduction.

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Port Competitiveness Evaluation By Fuzzy Multicriteria Grade Classification Model, Wen-Chih Huang, Junn-Yuan Teng, Miin-Jye Huang, Ming-Shin Kou Mar 2003

Port Competitiveness Evaluation By Fuzzy Multicriteria Grade Classification Model, Wen-Chih Huang, Junn-Yuan Teng, Miin-Jye Huang, Ming-Shin Kou

Journal of Marine Science and Technology–Taiwan

Competitiveness measurement of ports should be different from business/enterprises of the private sector. It needs to consider operational efficiency and overall effectiveness. Therefore, this paper attempts to establish a multi-criteria evaluation model. We develop Fuzzy Multi-criteria Grade Classification (FMGC) model to serve the purpose. This model is primarily for qualitative analysis, but this study invites quantitative indicators. It concurrently takes efficiency and effectiveness indicators into consideration. FMGC evaluates port competitiveness classification by partial order based on five grades. Partial order is sufficient to present superiority of port competitiveness. This paper takes eight East Asian container seaports for empirical study, also …

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Monitoring Of Sandstorms With Rocsat-1 Oci Data, Shih-Jen Huang, Gin-Rong Liu, Tsung-Hua Kuo, Tang-Huang Lin, Chih-Kang Liang Dec 2002

Monitoring Of Sandstorms With Rocsat-1 Oci Data, Shih-Jen Huang, Gin-Rong Liu, Tsung-Hua Kuo, Tang-Huang Lin, Chih-Kang Liang

Journal of Marine Science and Technology–Taiwan

The Ocean Color Imager (OCI) onboard the ROCSAT-1 Satellite was employed to demonstrate its capability in monitoring sandstorm events around Mongolia and northwestern China where they have been occurring in great frequency over these past few years. The OCI measures the radiance from the visible to near infrared regions in six spectral channels. The radiance can be used to calculate the aerosol optical depth (AOD) of the atmosphere through an atmospheric correction algorithm. The variation in the AOD during January and February of 2001 is investigated in this study. A set of OCI images covering the Yellow Sea was selected …

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Experimental Nonlinear Modeling Of A Rotating Machine With An Oil Film Bearing, Chiou-Fong Chung, Pi-Cheng Tung, Chiang-Nan Chang Dec 2002

Experimental Nonlinear Modeling Of A Rotating Machine With An Oil Film Bearing, Chiou-Fong Chung, Pi-Cheng Tung, Chiang-Nan Chang

Journal of Marine Science and Technology–Taiwan

In this study the system identification method is applied to obtain a nonlinear equation for an oil film rotating system. The centrifugal force induced by an unbalanced mass is used as the input signal for identification, and the phase between the input signal and the measured output vibration amplitude is calculated to perform the identification. Stability analysis and system performance are evaluated by using the root locus and the Floquet-Liapunov theorem. Based on the model, the oil whirl of the journal bearing can be predicted. A comparison between the simulation results and some experimented data shows the feasibility of the …

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Fast Convergence Control Approach For High Dimensional Chaotic Systems, Hsun-Heng Tsai, Chyun-Chau Fuh, Pi-Cheng Tung Dec 2002

Fast Convergence Control Approach For High Dimensional Chaotic Systems, Hsun-Heng Tsai, Chyun-Chau Fuh, Pi-Cheng Tung

Journal of Marine Science and Technology–Taiwan

A simple and efficient method for controlling high dimensional discrete-time chaotic systems is proposed in this paper. This method is implemented similar to the OGY method, and is feasible for practical experiments. The key component is to assign the eigenvalues of a linearized map by using the well-known pole placement technique. According to the Cayley-Hamilton theorem, the trajectory will converge to the desired fixed point after n iterations at most (n is the dimension of the map), if the real trajectory of the chaotic system falls within the neighborhood of the desired fixed point. The proposed approach improves the convergence …

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