Feasibility study of offshore wind turbine substructures for southwest offshore wind farm project in Korea

Shi, Wei,Han, Jonghoon,Kim, Changwan,Lee, Daeyong,Shin, Hyunkyoung,Park, Hyunchul Elsevier 2015 RENEWABLE ENERGY Vol.74 No.-

<P><B>Abstract</B></P> <P>Korea has huge potential for offshore wind energy and the first Korean offshore wind farm has been initiated off the southwest coast. With increasing water depth, different substructures of the offshore wind turbine, such as the jacket and multipile, are the increasing focus of attention because they appear to be cost-effective. However, these substructures are still in the early stages of development in the offshore wind industry. The aim of the present study was to design a suitable substructure, such as a jacket or multipile, to support a 5 MW wind turbine in 33 m deep water for the Korean Southwest Offshore Wind Farm. This study also aimed to compare the dynamic responses of different substructures including the monopile, jacket and multipile and evaluate their feasibility. We therefore performed an eigenanalysis and a coupled aero-hydro-servo-elastic simulation under deterministic and stochastic conditions in the environmental conditions in Korea. The results showed that the designed jacket and multipile substructures, together with the modified monopile, were well located at soft–stiff intervals, where most modern utility-scale wind turbine support structures are designed. The dynamic responses of the different substructures showed that of the three substructures, the performance of the jacket was very good. In addition, considering the simple configuration of the multipile, which results in lower manufacturing cost, this substructure can provide another possible solution for Korean’s first offshore wind farm. This study provides knowledge that can be applied for the deployment of large-scale offshore wind turbines in intermediate water depths in Korea.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A jacket as well as a multipile substructure was designed to support 5MW OWT for Korean offshore demonstration project in 33 m water depth. </LI> <LI> A fully coupled dynamic analysis was conducted based on Korean environmental conditions. </LI> <LI> The dynamic responses of the three substructures were compared to find their feasibility. </LI> <LI> The jacket had the best performance in terms of the investigated loads. </LI> <LI> The multipile results were comparable with the jacket substructure. </LI> </UL> </P>

Dynamic Analysis of Three-Dimensional Drivetrain System of Wind Turbine

Shi, Wei,Park, Hyun-Chul,Na, Sangkwon,Song, Jinseop,Ma, Sangjin,Kim, Chang-Wan Korean Society for Precision Engineering 2014 International Journal of Precision Engineering and Vol.15 No.7

In our previous study, a torsional model was used to perform a dynamic analysis of a wind turbine drivetrain. However, detailed characteristics could not be obtained with this torsional model. In this paper, the mathematical model of the wind turbine drivetrain is extended to a three-dimensional dynamic model. A typical arrangement with one low-speed planetary gear stage and two high-speed spur gear stages is used in this work. The governing equation of the drivetrain is derived by using Lagrange's equation. Lagrange's equation takes into account the kinetic energy of each component and potential energies from the shaft, bearing, and gear mesh. The governing equation is solved numerically using direct numerical integration. A dynamic analysis is carried out to investigate the transient response of the drivetrain system.

Soil-structure interaction on the response of jacket-type offshore wind turbine

Shi, Wei,Park, Hyun Chul,Chung, Chin Wah,Shin, Hyun Kyung,Kim, Sang Hoon,Lee, Sung Soo,Kim, Chang Wan SPRINGER 2015 INTERNATIONAL JOURNAL OF PRECISION ENGINEERING AND Vol. No.

Effects of xonotlite additive and forming pressure on the properties of the SiO2-based nanoporous thermal insulation materials

Shiwei Liu,Jingkun Yu,Lu Han,Beiyue Ma 한양대학교 세라믹연구소 2018 Journal of Ceramic Processing Research Vol.19 No.3

Nanoporous thermal insulation materials prepared with fumed SiO2 possess excellent thermal insulation property, and havebeen attracted much attention, but their mechanical properties are poor. Adding a small amount of fiber materials as atoughening material can improve the mechanical properties of the nanoporous thermal insulation materials. However, toomuch fiber materials additives will seriously affect the thermal insulation property. In this study, SiO2-based nanoporousthermal insulation materials were prepared, and the effects of addition amounts of xonotlite and forming pressure on themechanical performance and thermal insulation performance of as-prepared thermal insulation materials were investigated. It was found that addition of 10% xonotlite and forming pressure of 2MPa were proper for the preparation of SiO2-basednanoporous thermal insulation materials. The compressive strength and thermal conductivity of as-prepared materials were0.34 MPa and 0.031 W·m−1·K−1, respectively.

Study on a New Fault Diagnosis Method Based on Combining Intelligent Technologies

Shiwei Li,Di Zhou 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.6

In allusion to more indeterminate information and higher speed request characteristic in fault diagnosis system, according to the intelligence complementary strategy, a new fault diagnosis(SWPSO-BPN) model based on combining improved particle swarm optimization (PSO) algorithm and Back-propagation(BP) neural network is proposed in this paper. In the SWPSO-BPN method, an improved PSO (SWPSO) algorithm is proposed to optimize the parameters of BP neural network in order to overcome the shortcomings of slow learning speed and being easy to fall into local minimum, and obtain the optimal values of parameter combination in the BP neural network(SWPSO-BPN) model. Then proposed SWPSO-BPN model is applied to diagnose the fault in order to obtain a new fault diagnosis (SWPSO-BPN-FD) method. Finally, the proposed SWPSO-BPN-FD method is used to test the data from bearing data center of CWRU. The experimental results show that the proposed SWPSO-BPN-FD method can accurately and effectively realize high precision fault diagnosis of rolling bearing. And this method takes on strong robustness and generalization ability.

The Ex-Situ Conservation of Ornamental Plants in China

Shiwei Zhao,Zuoshuang Zhang 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

Fucosylated Chondroitin Sulfate From Sea Cucumber Improves Glucose Metabolism and Activates Insulin Signaling in the Liver of Insulin-Resistant Mice

Shiwei Hu,Ying-Ying Tian,Yao-Guang Chang,Zhao-Jie Li,Chang-Hu Xue,Yu-Ming Wang 한국식품영양과학회 2014 Journal of medicinal food Vol.17 No.7

This study investigated the effects of fucosylated chondroitin sulfate (CHS) isolated from sea cucumber on glucose metabolism and insulin signaling in the liver of insulin-resistant C57BL/6 mice fed a high-fat, high-sucrose diet (HFSD). Male C57BL/6J mice were randomly assigned into six groups: control; HFSD; 1mg RSG/kg$body weight (RSG); 80 mg CHS/kg$body weight (CHS); 20 mg CHS + 1mg RSG/kg$body weight (20 CHS + RSG); and 80 mg CHS + 1mg RSG/kg$body weight (80 CHS + RSG). Blood glucose, insulin parameters, glucose metabolism-related enzymes activities and insulin-signaling transducers in the liver were analyzed at 19 weeks. Results showed that CHS significantly decreased body weight gain, adipose tissue weight, and fasting blood glucose and serum insulin levels in insulin-resistant mice. Rosiglitazone (RSG) is an effective thiazolidinedione hypoglycemic agent, and CHS synergistically enhanced the effect of RSG. CHS feeding normalized the activities of hexokinase, pyruvate kinase, glycogen phosphorylase, glucose-6-phosphatase, and increased glycogen reserves in the liver. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis showed that CHS promoted the mRNA expression of insulin receptors (IR), insulin receptor substrate 2 (IRS-2), phosphatidylinositol 3 kinase (PI3K), protein kinase B (PKB), and glycogen synthase (GS) in the liver of insulin resistant mice, and inhibited glycogen synthase kinase-3 (GSK-3b) mRNA expression. The results suggested that CHS treatment improved glucose metabolism by modulating metabolic enzymes and promoting the PI3K/PKB/GSK-3b signaling pathway mediated by insulin at the transcriptional level. These results provided strong justification for the development of CHS as a functional food.

Cloning and Characterization of the Ammonium Transporter Genes BaAMT1;1 and BaAMT1;3 from Chinese Kale

Shiwei Song,Riyuan Chen,Zhenhua He,Xinmin Huang,Lihua Zhong,Houcheng Liu,Guangwen Sun 한국원예학회 2017 Horticulture, Environment, and Biotechnology Vol.58 No.2

Chinese kale (Brassica alboglabra L.) is a popular vegetable rich in important nutrients. Fertilization withappropriate ammonium:nitrate ratios enhances biomass production and quality. AMT-type ammonium transporters havebeen shown to mediate ammonium uptake across the plasma membrane. However, very little is known about themolecular regulation of growth and development by ammonium in Chinese kale, including how ammonium regulatesthe expression of AMT1 genes. In this study, we identified and characterized two AMT1 genes from B. alboglabra,BaAMT1;1 and BaAMT1;3. The full-length open reading frames of BaAMT1;1 and BaAMT1;3 were 1512 bp and1515 bp, respectively. Transient expression of the fusion proteins pBE-EGFP-BaAMT1;1 and pBE-EGFP-BaAMT1;3 inonion epidermal cells indicated that these transporters are located on the plasma membrane. BaAMT1;1 and BaAMT1;3were functional in yeast and complemented a mutant defective in ammonium transport. BaAMT1;1 was expressed invegetative organs and at high levels in roots, while BaAMT1;3 expression was root specific. In addition, we observedopposite responses of BaAMT1;1 and BaAMT1;3 expression to nitrogen starvation and ammonium resupply in roots. These results provide new insights into the molecular mechanisms underlying ammonium absorption in Chinese kale.

Immobilization of Copper in Brown Soil Using Different Amendments

Shiwei Zhou,Zhihong Yu,Fei Lian,Zhongqi Liu,Hua Zhang,Zhengguo Song 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Low Temperature during Seedling Stage Promotes Female Flower Determination but Not Yield of Chieh-qua

Shiwei Song,Hongxing Huang,Houcheng Liu,Guangwen Sun,Riyuan Chen 한국원예학회 2012 Horticulture, Environment, and Biotechnology Vol.53 No.5

Temperature has an important effect on plant growth and sex determination in flowers. The effect of different temperatures (high temperature: 30 /25 (day/night), medium temperature: 25 /18 and low temperature: 15 /10 )on flower sex determination and fruit yield was studied in Chieh-qua (Benincasa hispida Cogn. var. Chieh-qua How. ‘No. 4 Jiang xin’), also the content of absicsic acid (ABA) and indole acetic acid (IAA) in the shoot apex was measured. The results showed that medium and low temperatures during seedling stage boost the female flower differentiation after transplanting, compared with high temperature treatment, and the effect was more obvious when the temperature was lower. Lower temperature increased the content of ABA and IAA in shoot apex of Chieh-qua. There was a positive relationship between the ratio of IAA/ABA and plant female flower determination under different temperature treatments (R = 0.8744). Temperature may affect female flower differentiation of Chieh-qua by changing the contents of ABA and IAA in shoot apex. Fruit yield was not significantly affected by different temperature treatments.