Research

15692 KiB

Open AccessArticle

Dynamic Analysis of Jacket Substructure for Offshore Wind Turbine Generators under Extreme Environmental Conditions

by Wen-Jeng Lai, Chin-Yu Lin, Chin-Cheng Huang and Rong-Mao Lee

Appl. Sci. 2016, 6(10), 307; https://doi.org/10.3390/app6100307 - 21 Oct 2016

Cited by 14 | Viewed by 10556

In order to develop dynamic analysis technologies regarding the design of offshore wind turbine generators (OWTGs), a special project called Offshore Code Comparison Collaboration Continuation (OC4) was conducted by IEA (International Energy Agency) in 2010. A similar project named INER-OC4 has been performed [...] Read more.

In order to develop dynamic analysis technologies regarding the design of offshore wind turbine generators (OWTGs), a special project called Offshore Code Comparison Collaboration Continuation (OC4) was conducted by IEA (International Energy Agency) in 2010. A similar project named INER-OC4 has been performed by the Institute of Nuclear Energy Research (INER) to develop the OWTG technologies of Taiwan. Since the jacket substructure will be applied to Taiwan OWTGs before 2020, the INER-OC4 project has been devoted to the design and analysis of jacket support structure. In this work, the preliminary result of INER-OC4 is presented. A simplified analysis procedure for jacket support structure has been proposed. Both of the NREL (National Renewable Energy Laboratory) 5 MW OWTG FAST model and OC4 jacket substructure model have been built and analyzed under severe design load cases (DLCs) of IEC (International Electrotechnical commission) 61400-3. Simulation results of six severe DLCs are performed in this work and the results are in agreement with the requirements of API (American Petroleum Institute) and NORSOK (Norwegian Petroleum Industry) standards. Full article

(This article belongs to the Special Issue Selected Papers from the 2015 International Conference on Inventions)

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4809 KiB

Open AccessArticle

Development of Dual-Axis MEMS Accelerometers for Machine Tools Vibration Monitoring

by Chih-Yung Huang and Jian-Hao Chen

Appl. Sci. 2016, 6(7), 201; https://doi.org/10.3390/app6070201 - 12 Jul 2016

Cited by 14 | Viewed by 8836

Abstract

With the development of intelligent machine tools, monitoring the vibration by the accelerometer is an important issue. Accelerometers used for measuring vibration signals during milling processes require the characteristics of high sensitivity, high resolution, and high bandwidth. A commonly used accelerometer is the [...] Read more.

With the development of intelligent machine tools, monitoring the vibration by the accelerometer is an important issue. Accelerometers used for measuring vibration signals during milling processes require the characteristics of high sensitivity, high resolution, and high bandwidth. A commonly used accelerometer is the lead zirconate titanate (PZT) type; however, integrating it into intelligent modules is excessively expensive and difficult. Therefore, the micro electro mechanical systems (MEMS) accelerometer is an alternative with the advantages of lower price and superior integration. In the present study, we integrated two MEMS accelerometer chips into a low-pass filter and housing to develop a low-cost dual-axis accelerometer with a bandwidth of 5 kHz and a full scale range of ±50 g for measuring machine tool vibration. In addition, a platform for measuring the linearity, cross-axis sensitivity and frequency response of the MEMS accelerometer by using the back-to-back calibration method was also developed. Finally, cutting experiments with steady and chatter cutting were performed to verify the results of comparing the MEMS accelerometer with the PZT accelerometer in the time and frequency domains. The results demonstrated that the dual-axis MEMS accelerometer is suitable for monitoring the vibration of machine tools at low cost. Full article

(This article belongs to the Special Issue Selected Papers from the 2015 International Conference on Inventions)

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2377 KiB

Open AccessArticle

A Fast Reactive Power Optimization in Distribution Network Based on Large Random Matrix Theory and Data Analysis

by Wanxing Sheng, Keyan Liu, Hongyan Pei, Yunhua Li, Dongli Jia and Yinglong Diao

Appl. Sci. 2016, 6(6), 158; https://doi.org/10.3390/app6060158 - 24 May 2016

Cited by 13 | Viewed by 5224

Abstract

In this paper, a reactive power optimization method based on historical data is investigated to solve the dynamic reactive power optimization problem in distribution network. In order to reflect the variation of loads, network loads are represented in a form of random matrix. [...] Read more.

In this paper, a reactive power optimization method based on historical data is investigated to solve the dynamic reactive power optimization problem in distribution network. In order to reflect the variation of loads, network loads are represented in a form of random matrix. Load similarity (LS) is defined to measure the degree of similarity between the loads in different days and the calculation method of the load similarity of load random matrix (LRM) is presented. By calculating the load similarity between the forecasting random matrix and the random matrix of historical load, the historical reactive power optimization dispatching scheme that most matches the forecasting load can be found for reactive power control usage. The differences of daily load curves between working days and weekends in different seasons are considered in the proposed method. The proposed method is tested on a standard 14 nodes distribution network with three different types of load. The computational result demonstrates that the proposed method for reactive power optimization is fast, feasible and effective in distribution network. Full article

(This article belongs to the Special Issue Selected Papers from the 2015 International Conference on Inventions)

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6719 KiB

Open AccessArticle

Innovative Methodology for Multi-View Point Cloud Registration in Robotic 3D Object Scanning and Reconstruction

by Liang-Chia Chen, Dinh-Cuong Hoang, Hsien-I Lin and Thanh-Hung Nguyen

Appl. Sci. 2016, 6(5), 132; https://doi.org/10.3390/app6050132 - 05 May 2016

Cited by 19 | Viewed by 8061

Abstract

The paper is concerned with the problem of multi-view three-dimensional (3D) point cloud registration. A novel global registration method is proposed to accurately register two series of scans into an object model underlying 3D imaging digitization by using the proposed oriented bounding box [...] Read more.

The paper is concerned with the problem of multi-view three-dimensional (3D) point cloud registration. A novel global registration method is proposed to accurately register two series of scans into an object model underlying 3D imaging digitization by using the proposed oriented bounding box (OBB) regional area-based descriptor. A robot 3D scanning strategy is nowadays employed to generate the complete set of point cloud of physical objects by using 3D robot multi-view scanning and data registration. The automated operation has to successively digitize view-dependent area-scanned point cloud from complex-shaped objects by simultaneous determination of the next best robot pose and multi-view point cloud registration. To achieve this, the OBB regional area-based descriptor is employed to determine an initial transformation matrix and is then refined employing the iterative closest point (ICP) algorithm. The key technical breakthrough can resolve the commonly encountered difficulty in accurately merging two neighboring area-scanned images when no coordinate reference exists. To verify the effectiveness of the strategy, the developed method has been verified through some experimental tests for its registration accuracy. Experimental results have preliminarily demonstrated the feasibility and applicability of the developed method. Full article

(This article belongs to the Special Issue Selected Papers from the 2015 International Conference on Inventions)

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1451 KiB

Open AccessArticle

Characterization and Clinical Trial of an Innovative High-Speed Lancing Device

by Ho Chang, Yao-Jen Yeh, Rahnfong Lee, Chia-Chun Lee and Jenq-Huey Shyu

Appl. Sci. 2016, 6(4), 111; https://doi.org/10.3390/app6040111 - 18 Apr 2016

Cited by 1 | Viewed by 4833

Abstract

An innovative high-speed lancing device has a lancet that moves so fast that it is not affected at all by the vibration of its spring, and does not pierce the skin repeatedly, greatly reducing the pain that is caused to diabetes mellitus (DM) [...] Read more.

An innovative high-speed lancing device has a lancet that moves so fast that it is not affected at all by the vibration of its spring, and does not pierce the skin repeatedly, greatly reducing the pain that is caused to diabetes mellitus (DM) patients during blood sampling. As revealed by experimental measurements of the acceleration of a lancet using an accelerometer, the lancet pierces the skin only once. The maximum acceleration and the instant piercing velocity of the lancet are 9.4 times and 1.78 times those of a conventional lancing device, respectively. Meanwhile, the period for which the lancet remains in the skin is 0.014 s shorter than that of the conventional lancing device. A clinical trial that involved 100 participants yielded statistical results concerning the numeric rating of pain scale (NRS) of pain intensity, which is internationally recognized as the pain with the highest validity, that showed that the NRS of participants who used the innovative high-speed lancing device was 2.65 less than that of those who used the conventional lancing device, and the duration of the pain after blood sampling was 76.1 min shorter. Full article

(This article belongs to the Special Issue Selected Papers from the 2015 International Conference on Inventions)

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5124 KiB

Open AccessArticle

Relationship between ISO 230-2/-6 Test Results and Positioning Accuracy of Machine Tools Using LaserTRACER

by Hau-Wei Lee, Jr-Rung Chen, Shan-Peng Pan, Hua-Chung Liou and Po-Er Hsu

Appl. Sci. 2016, 6(4), 105; https://doi.org/10.3390/app6040105 - 12 Apr 2016

Cited by 13 | Viewed by 8382

Abstract

To test the positioning accuracy and repeatability of the linear axes of machine tools, ISO (International Standards Organization) 230-2 and ISO 230-6 are usually adopted. Auto-tracking laser interferometers (ATLI) can perform the testing for the positioning accuracy and the repeatability including x-, [...] Read more.

To test the positioning accuracy and repeatability of the linear axes of machine tools, ISO (International Standards Organization) 230-2 and ISO 230-6 are usually adopted. Auto-tracking laser interferometers (ATLI) can perform the testing for the positioning accuracy and the repeatability including x-, y- and z-axes according to ISO 230-2 as well as xy, xz, yz, and xyz diagonal lines following ISO 230-6. LaserTRACER is a kind of ATLI. One of the steps of the ISO 230-2 and -6 tests using LaserTRACER is to determine the coordinate of the LaserTRACER with respect to the home point of the machine tool. Positioning accuracy of the machine tool causes the coordinate determined error, which might influence the test result. To check on this error, this study performs three experiments. The experiment results show that the positioning error appears on the testing results. Full article

(This article belongs to the Special Issue Selected Papers from the 2015 International Conference on Inventions)

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2409 KiB

Open AccessArticle

Investigation of Polishing Pads Impregnated with Fe and Al₂O₃ Particles for Single-Crystal Silicon Carbide Wafers

by Jihng-Kuo Ho, Chih-Yung Huang, Ming-Yi Tsai and Che-Cheng Tsai

Appl. Sci. 2016, 6(3), 89; https://doi.org/10.3390/app6030089 - 22 Mar 2016

Cited by 15 | Viewed by 6754

Abstract

This study focuses on the development of a novel polishing pad for SiC wafers. Fe and Al₂O₃ particles were impregnated in a polyurethane matrix, thus forming a fixed abrasive polishing pad. Four types of pads with different compositions of Fe [...] Read more.

This study focuses on the development of a novel polishing pad for SiC wafers. Fe and Al₂O₃ particles were impregnated in a polyurethane matrix, thus forming a fixed abrasive polishing pad. Four types of pads with different compositions of Fe and Al₂O₃ were fabricated. A combination of loose and fixed polishing methods was used for polishing with the fabricated pads and was investigated to improve the polishing process. The surface characteristics of the polished SiC wafer and the SiC removal rate during polishing using the designed pads were examined and compared with those for SiC polished with a conventional polyurethane pad. Experimental results showed that the removal rate for SiC in the case of polishing with the pads consisting 1 wt % Fe and 3 wt % Al₂O₃ particles was approximately 73% higher than that observed when polishing using the conventional polyurethane polishing pad. Additionally, the surface roughness of the resulting SiC wafers after polishing with the Fe and Al₂O₃-impregnated pads was identical to that when using the conventional polyurethane pad, without any surface damage. The results indicated that the Fe and Al₂O₃-impregnated pads can be effectively used for SiC wafer polishing. When the proposed process was employed for polishing single-crystal SiC, both the polishing time and cost were reduced. This novel design can facilitate the extensive use of single-crystal SiC wafers in the future. Full article

(This article belongs to the Special Issue Selected Papers from the 2015 International Conference on Inventions)

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1103 KiB

Open AccessArticle

Optimization of Minimum Quantity Lubricant Conditions and Cutting Parameters in Hard Milling of AISI H13 Steel

by The-Vinh Do and Quang-Cherng Hsu

Appl. Sci. 2016, 6(3), 83; https://doi.org/10.3390/app6030083 - 16 Mar 2016

Cited by 52 | Viewed by 5550

Abstract

As a successful solution applied to hard machining, the minimum quantity lubricant (MQL) has already been established as an alternative to flood coolant processing. The optimization of MQL parameters and cutting parameters under MQL condition are essential and pressing. The study was divided [...] Read more.

As a successful solution applied to hard machining, the minimum quantity lubricant (MQL) has already been established as an alternative to flood coolant processing. The optimization of MQL parameters and cutting parameters under MQL condition are essential and pressing. The study was divided into two parts. In the first part of this study, the Taguchi method was applied to find the optimal values of MQL condition in the hard milling of AISI H13 with consideration of reduced surface roughness. The L9 orthogonal array, the signal-to-noise (S/N) ratio and analysis of variance (ANOVA) were employed to analyze the effect of the performance characteristics of MQL parameters (i.e., cutting fluid type, pressure, and fluid flow) on good surface finish. In the results section, lubricant and pressure of MQL condition are determined to be the most influential factors which give a statistically significant effect on machined surfaces. A verifiable experiment was conducted to demonstrate the reliability of the results. In the second section, the optimized MQL parameters were applied in a series of experiments to find out cutting parameters of hard milling. The Taguchi method was also used to optimize the cutting parameters in order to obtain the best surface roughness. The design of the experiment (DOE) was implemented by using the L27 orthogonal array. Based on an analysis of the signal-to-noise response and ANOVA, the optimal values of cutting parameters (i.e., cutting speed, feed rate, depth-of-cut and hardness of workpiece) were introduced. The results of the present work indicate feed rate is the factor having the most effect on surface roughness. Full article

(This article belongs to the Special Issue Selected Papers from the 2015 International Conference on Inventions)

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5171 KiB

Open AccessArticle

Mechanical Behavior and Fracture Properties of NiAl Intermetallic Alloy with Different Copper Contents

by Tao-Hsing Chen and Jian-Hong Wu

Appl. Sci. 2016, 6(3), 70; https://doi.org/10.3390/app6030070 - 02 Mar 2016

Cited by 12 | Viewed by 5970

Abstract

The deformation behavior and fracture characteristics of NiAl intermetallic alloy containing 5~7 at% Cu are investigated at room temperature under strain rates ranging from 1 × 10⁻³ to 5 × 10³ s⁻¹. It is shown that the [...] Read more.

The deformation behavior and fracture characteristics of NiAl intermetallic alloy containing 5~7 at% Cu are investigated at room temperature under strain rates ranging from 1 × 10⁻³ to 5 × 10³ s⁻¹. It is shown that the copper contents and strain rate both have a significant effect on the mechanical behavior of the NiAl alloy. Specifically, the flow stress increases with an increasing copper content and strain rate. Moreover, the ductility also improves as the copper content increases. The change in the mechanical response and fracture behavior of the NiAl alloy given a higher copper content is thought to be the result of the precipitation of β-phase (Ni,Cu)Al and γ'-phase (Ni,Cu)₃Al in the NiAl matrix. Full article

(This article belongs to the Special Issue Selected Papers from the 2015 International Conference on Inventions)

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5243 KiB

Open AccessArticle

Photonic Crystal-Based Sensors for Detecting Alcohol Concentration

by Wen-Kai Kuo, Hsueh-Ping Weng, Jyun-Jheng Hsu and Hsin Her Yu

Appl. Sci. 2016, 6(3), 67; https://doi.org/10.3390/app6030067 - 26 Feb 2016

Cited by 45 | Viewed by 9118

Abstract

Polystyrene (PS) opal and titania (TiO₂) inverse opal films were fabricated by the self-assembly colloidal crystal template technique. Based on Bragg’s law, these sensors were used to detect the different concentrations of ethanol solution. The results indicated that TiO₂ inverse [...] Read more.

Polystyrene (PS) opal and titania (TiO₂) inverse opal films were fabricated by the self-assembly colloidal crystal template technique. Based on Bragg’s law, these sensors were used to detect the different concentrations of ethanol solution. The results indicated that TiO₂ inverse opal films were advantageous over PS opal film for detecting the ethanol concentration. TiO₂ inverse opal films sintered at 600 °C retained the highest sensitivity for ethanol concentration identification, since the anatase phase was transformed into the rutile phase, which resulted in an enhancement of the refractive index, i.e., an increase in the amount of the red shift. Full article

(This article belongs to the Special Issue Selected Papers from the 2015 International Conference on Inventions)

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1654 KiB

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Investigations on the Cosputtered ITO-ZnO Transparent Electrode Ohmic Contacts to n-GaN

by Wei-Hua Hsiao, Tai-Hong Chen, Li-Wen Lai, Ching-Ting Lee, Jyun-Yong Li, Hong-Jyun Lin, Nan-Jay Wu and Day-Shan Liu

Appl. Sci. 2016, 6(2), 60; https://doi.org/10.3390/app6020060 - 22 Feb 2016

Cited by 2 | Viewed by 7232

Abstract

Transparent indium tin oxide (ITO) and cosputtered ITO-zinc oxide (ZnO) films’ contacts to an n-GaN epilayer were investigated. Both of these electrodes’ contact to the n-GaN epilayer showed Schottky behavior, although the contact resistance of the ITO-ZnO/n-GaN system was [...] Read more.

Transparent indium tin oxide (ITO) and cosputtered ITO-zinc oxide (ZnO) films’ contacts to an n-GaN epilayer were investigated. Both of these electrodes’ contact to the n-GaN epilayer showed Schottky behavior, although the contact resistance of the ITO-ZnO/n-GaN system was lower than that of the ITO/n-GaN system. By placing a thin Ti interlayer between the ITO-ZnO/n-GaN interface, nonalloyed ohmic contact was achieved. The inset Ti interlayer was both beneficial both for enhancing the outdiffusion of the nitrogen atoms at the surface of the n-GaN and suppressing the indiffusion of oxygen atoms from the surface of the ITO-ZnO to n-GaN. The figure-of-merit (FOM), evaluated from the specific contact resistance and optical property of the Ti/ITO-ZnO system’s contact to the n-GaN epilayer, was optimized further at an adequate thickness of the Ti interlayer. Full article

(This article belongs to the Special Issue Selected Papers from the 2015 International Conference on Inventions)

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3230 KiB

Open AccessArticle

Implementation of FPGA-Based Charge Control for a Self-Sufficient Solar Tracking Power Supply System

by Jui-Ho Chen, Her-Terng Yau and Jin-Han Lu

Appl. Sci. 2016, 6(2), 41; https://doi.org/10.3390/app6020041 - 02 Feb 2016

Cited by 12 | Viewed by 7321

Abstract

This study used a field-programmable gate array (FPGA) with a Xilinx Spartan-3 FPGA to implement Reflex charge control in a dual-axis solar tracking system with maximum power point tracking (MPPT). The chaos embedded particle swarm optimization method was used to search for the [...] Read more.

This study used a field-programmable gate array (FPGA) with a Xilinx Spartan-3 FPGA to implement Reflex charge control in a dual-axis solar tracking system with maximum power point tracking (MPPT). The chaos embedded particle swarm optimization method was used to search for the optimum gain constants of the PI controller and the Reflex charging frequency. This scheme not only increases the output power of solar panels but also has a significant effect on switching loss and oscillation of solar charging. The experiment results showed that the proposed method can also significantly improve temperature rise, and that charging efficiency is also better than it is in a traditional charge mode. The results also showed that charging power was enough for solar tracking and the requirements of the charging system. The most significant contribution of this paper is that the scheme can be applied to any active solar tracking and charging system. Full article

(This article belongs to the Special Issue Selected Papers from the 2015 International Conference on Inventions)

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1292 KiB

Open AccessArticle

The Effects of Adhesive and Bonding Length on the Strain Transfer of Optical Fiber Sensors

by Shiuh-Chuan Her and Chih-Ying Huang

Appl. Sci. 2016, 6(1), 13; https://doi.org/10.3390/app6010013 - 11 Jan 2016

Cited by 27 | Viewed by 4839

Abstract

Optical fiber sensors have been extensively adapted as structural health monitoring devices. Due to the existence of the adhesive layer, a portion of the strain is absorbed by the adhesive. As a result, the structural strain sensed by the optical fiber is underestimated [...] Read more.

Optical fiber sensors have been extensively adapted as structural health monitoring devices. Due to the existence of the adhesive layer, a portion of the strain is absorbed by the adhesive. As a result, the structural strain sensed by the optical fiber is underestimated and required to be corrected. An analytical solution is presented through which it is possible to establish the relationship between the strains in the host structure and the surface bonded optical fiber sensor. Experimental measurements based on the Mach–Zehnder interferometric technique were performed to validate the theoretical prediction and reveal the differential strains between the optical fiber strain sensor and test specimen. Parametric studies show that the percentage of the strain in the test specimen actually transferred to the optical fiber is dependent on the bonding length of the optical fiber and the adhesive. The strain transfer is increasing from 56% to 82% as the bonding length increases from 5 cm to 12 cm with the epoxy adhesive. The general trend of the strain transfer obtained from both experimental tests and theoretical predictions shows that the longer the bonding length and the stiffer the adhesive, the more strain is transferred to the optical fiber. Full article

(This article belongs to the Special Issue Selected Papers from the 2015 International Conference on Inventions)

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2471 KiB

Open AccessArticle

A Notched Long-Period Fiber Grating Magnetic Field Sensor Based on Nanoparticle Magnetic Fluid

by Sheng-Feng Wang and Chia-Chin Chiang

Appl. Sci. 2016, 6(1), 9; https://doi.org/10.3390/app6010009 - 04 Jan 2016

Cited by 13 | Viewed by 5778

Abstract

In this paper, we propose using an inductively coupled plasma (ICP) etching technique to fabricate a notched long-period fiber grating (NLPFG) for magnetic sensing application. An optical fiber magnetic field sensor based on NLPFG filled with nanoparticle magnetic fluid is proposed and demonstrated. [...] Read more.

In this paper, we propose using an inductively coupled plasma (ICP) etching technique to fabricate a notched long-period fiber grating (NLPFG) for magnetic sensing application. An optical fiber magnetic field sensor based on NLPFG filled with nanoparticle magnetic fluid is proposed and demonstrated. The magnetic fluid nanoparticles were attached on the grating structure section and used as a magneto-optical sensing layer to measure magnetic flux density. The external applied magnetic flux density ranged from 0 to 27.74 mT. As the magnetic flux density was increased, the spectra of the NLPFG were changed. The resonant wavelength of the attenuation band did not shift obviously, but the transmission loss of the resonant dip was increased by 3.48 dB from −19.41 dB to −15.93 dB. The experimental results indicated that the sensitivity of the sensor is approximately 0.125 dB/mT. Full article

(This article belongs to the Special Issue Selected Papers from the 2015 International Conference on Inventions)

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