SSR and SCAR mapping of a multiple-allele male-sterile gene in Chinese cabbage (Brassica rapa L.)

Feng, Hui,Wei, Peng,Piao, Zhong-Yun,Liu, Zhi-Yong,Li, Cheng-Yu,Wang, Yu-Gang,Ji, Rui-Qin,Ji, Shu-Juan,Zou, Ting,Choi, Su-Ryun,Lim, Yong-Pyo Springer-Verlag 2009 TAG. Theoretical and applied genetics. Theoretisch Vol.119 No.2

Influences of flow loss and inlet distortions from radial inlets on the performances of centrifugal compressor stages

Fenghui Han,Yijun Mao,Jiajian Tan 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.10

Radial inlets are typical upstream components of multistage centrifugal compressors. Unlike axial inlets, radial inlets generate additional flow loss and introduce flow distortions at impeller inlets. Such distortions negatively affect the aerodynamic performance of compressor stages. In this study, industrial centrifugal compressor stages with different radial inlets are investigated via numerical simulations. Two reference models were built, simulated, and compared with each original compressor stage to analyze the respective and coupling influences of flow loss and inlet distortions caused by radial inlets on the performances of the compressor stage and downstream components. Flow loss and inlet distortions are validated as the main factors through which radial inlets negatively affect compressor performance. Results indicate that flow loss inside radial inlets decreases the performance of the whole compressor stage but exerts minimal effect on downstream components. By contrast, inlet distortions induced by radial inlets negatively influence the performance of the whole compressor stage and exert significant effects on downstream components. Therefore, when optimizing radial inlets, the reduction of inlet distortions might be more effective than the reduction of flow loss. This research provides references and suggestions for the design and improvement of radial inlets.

Large-scale flow measurements and analysis for radial inlets of industrial centrifugal compressors based on multi-hole probe system

Fenghui Han,Zhe Wang,Yijun Mao,Yiyun Zhang,Jiajian Tan 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.1

Multi-hole probe (MHP), as a classical measuring instrument, continues to play an important role in the pressure and velocity measurements for industrial applications by virtue of its robust and reliable performance as well as the simple structure and low cost. But the flow directionality limitations and the low efficiency of traditional operations become obstacles to the large-scale measurements of MHPs. In this paper, an improved operating method is adopted for conventional MHPs to extend their measuring range of incidence angles, and a corresponding auto-measuring system has been developed to realize automatic calibration and measurement of MHPs for industrial large-scale flow measurements. Measurement uncertainties of the system have been experimentally analyzed, verifying a good accuracy: errors of 0.36° in pitch angle, 0.40° in yaw angle and 0.83% in velocity magnitude (95% CI). Furthermore, this auto-measuring system has been applied in the large-scale measurements on different radial inlets for industrial centrifugal compressors, which provide valuable flow information that was not previously available for industrial productions and assist with the improvement study. Analysis and applications in this paper prove that the developed system not only reduces the flow directionality limitations of conventional MHPs, but also significantly improves the experimental efficiency and the control-precision of the probe, achieves a good repeatability and ensures the reliability of the experimental data, which satisfies the requirements of large-scale measurements in industrial applications. Meanwhile, the portability of the system makes it more convenient and flexible to be applied in various industrial productions.

Application of inverse reliability method to estimation of flutter safety factors of suspension bridges

Jin Cheng,Fenghui Dong 한국풍공학회 2017 Wind and Structures, An International Journal (WAS Vol.24 No.3

An efficient and accurate algorithm is proposed to estimate flutter safety factor of suspension bridges satisfying prescribed reliability levels. Uncertainties which arise from the basic wind speed at the bridge deck location, critical flutter velocity, the wind conversion factor from a scaled model to the prototype structure and the gust speed factor are incorporated. The proposed algorithm integrates the concepts of the inverse reliability method and the calculation method of the critical flutter velocity of suspension bridges. The unique feature of the proposed method is that it offers a tool for flutter safety assessment of suspension bridges, when the reliability level is specified as a target to be satisfied by the designer. Accuracy and efficiency of this method with reference to three example suspension bridges is studied and numerical results validate its superiority over conventional deterministic method. Finally, the effects of various parameters on the flutter safety factor of suspension bridges are also investigated.

Ensembles of neural network with stochastic optimization algorithms in predicting concrete tensile strength

Juan Hu,Fenghui Dong,Yiqi Qiu,Lei Xi,Ali Majdi,H. Elhosiny Ali 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.45 No.2

Proper calculation of splitting tensile strength (STS) of concrete has been a crucial task, due to the wide use of concrete in the construction sector. Following many recent studies that have proposed various predictive models for this aim, this study suggests and tests the functionality of three hybrid models in predicting the STS from the characteristics of the mixture components including cement compressive strength, cement tensile strength, curing age, the maximum size of the crushed stone, stone powder content, sand fine modulus, water to binder ratio, and the ratio of sand. A multi-layer perceptron (MLP) neural network incorporates invasive weed optimization (IWO), cuttlefish optimization algorithm (CFOA), and electrostatic discharge algorithm (ESDA) which are among the newest optimization techniques. A dataset from the earlier literature is used for exploring and extrapolating the STS behavior. The results acquired from several accuracy criteria demonstrated a nice learning capability for all three hybrid models viz. IWO-MLP, CFOA-MLP, and ESDA-MLP. Also in the prediction phase, the prediction products were in a promising agreement (above 88%) with experimental results. However, a comparative look revealed the ESDA-MLP as the most accurate predictor. Considering mean absolute percentage error (MAPE) index, the error of ESDAMLP was 9.05%, while the corresponding value for IWO-MLP and CFOA-MLP was 9.17 and 13.97%, respectively. Since the combination of MLP and ESDA can be an effective tool for optimizing the concrete mixture toward a desirable STS, the last part of this study is dedicated to extracting a predictive formula from this model.

A Simplified Method for Free Vibration Analysis of Cable-stayed Bridges

Jin Cheng,Fenghui Dong 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.1

A simplified method for the accurate prediction of the natural frequencies of cable-stayed bridges is proposed in this paper. In the proposed method artificial neural network (ANN) is applied to derive a simple formula to predict the natural frequencies of cable-stayed bridges based on existing natural frequency data. Unlike in the existing empirical methods, no functional relationship among the variables is assumed before we can develop an ANN model. ANN automatically constructs the relationships and adapts based on the training data presented to them. Also, the proposed method takes into account the wide range of parameters which may have a significant effect on the natural frequencies of cable-stayed bridges. The proposed method is particularly useful for the preliminary design stage of cable-stayed bridges where free vibration analysis needs to be carried out. The proposed method is compared with two existing empirical methods. It is found that the simplified method proposed in this study can produce a more accurate prediction of the natural frequencies of cable-stayed bridges than the existing empirical methods.

A thermal design method for the performance optimization of multi-stream plate-fin heat exchangers

Zhe Wang,Fenghui Han,Bengt Sundén,Yanzhong Li 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.6

An optimization design method based on field synergy principle is developed for Multi-stream plate-fin heat exchangers (MPHEs)with a segmented differential model. The heat exchanger is divided into a number of sub-exchangers along the main stream, and eachsub-exchanger consists of N passages along the height of the exchanger. Compared with the traditional heat exchanger design, this methodallows temperature and pressure fields to be obtained via coupling calculation with consideration of variable physical properties andthe axial heat loss of the heat exchanger. Finally, the heat exchanger is optimally designed using a temperature-difference uniformityoptimization factor based on field synergy principle. This design model can provide an accurate temperature field and pressure field,because the stream properties are determined by the mean temperature and pressure of each local sub-exchanger. Optimum results indicatethat the temperature distribution on the cross section of the heat exchanger is relatively uniform and that the temperature differenceof heat transfer for each stream is always a small value. These characteristics prove the feasibility and effectiveness of this design model. In this paper, a case of five stream plate-fin heat exchangers for an ethylene plant is designed under a practical cold box operating conditionwith the proposed model, the structure and heat transfer of which are optimally determined. The design model and optimizationmethod proposed in this work can provide theoretical and technical support to the optimization design of MPHEs.

Application of inverse reliability method to estimation of flutter safety factors of suspension bridges

Cheng, Jin,Dong, Fenghui Techno-Press 2017 Wind and Structures, An International Journal (WAS Vol.24 No.3

An efficient and accurate algorithm is proposed to estimate flutter safety factor of suspension bridges satisfying prescribed reliability levels. Uncertainties which arise from the basic wind speed at the bridge deck location, critical flutter velocity, the wind conversion factor from a scaled model to the prototype structure and the gust speed factor are incorporated. The proposed algorithm integrates the concepts of the inverse reliability method and the calculation method of the critical flutter velocity of suspension bridges. The unique feature of the proposed method is that it offers a tool for flutter safety assessment of suspension bridges, when the reliability level is specified as a target to be satisfied by the designer. Accuracy and efficiency of this method with reference to three example suspension bridges is studied and numerical results validate its superiority over conventional deterministic method. Finally, the effects of various parameters on the flutter safety factor of suspension bridges are also investigated.

Probabilistic Analysis on Aerostatic Displacement-dependent Wind Loads on a Stream-lined Box Girder

Feng Shi,Libin Wang,Fenghui Dong,Min Zhao 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.1

Due to the limitations of the bridge deck modeling and wind tunnel installations, the parametricuncertainties of aerostatic displacement-dependent wind loads have become an urgent problem for reliability analysis in bridge engineering. Computational fluid dynamic (CFD) simulations were conducted to investigate the distribution model of aerostatic coefficients. The Monte Carlo simulation (MCS) was used to generate random samples of stream-lined box cross-sections. Among these samples, wind attack angles of -8° – 8° were considered, and the sample size of each angle group was set as 30. Then, the statistical properties for the variation and distribution of aerostatic coefficients were discussed. In addition, sub-samples with sizes of 5 – 20 were randomly sampled from the initial sample group to evaluate the influence of the sample scale. The coefficient of variation (COV) of aerostatic coefficients with respect to geometric uncertainties increased up to 0.217, which occurred at -7° wind attack angle. Lognormal distribution models obtained by hypothesis tests maintained a low deviation for estimating the distribution of aerostatic coefficients. The sample size had a significant effect on quantifying the error between empirical and theoretical distribution models. Simulation method proposed in this paper provides a systematic approach for probabilistic problems involving fluid-structure interaction and parametric uncertainties.

Mechanical Behavior in Perfobond Rib Shear Connector with UHPC-Steel Composite Structure with Coarse Aggregate

Maojun Duan,Shiyu Zhang,Xu Wang,Fenghui Dong 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.4

Using experimental and numerical analysis, this paper aims at investigating the mechanical behavior in Perfobond rib (PBL) shear connectors with ultrahigh-performance concrete (UHPC)-steel composite structures. Twelve push-out specimens fabricated according to the design used for the connectors in the UHPC-steel composite structures in bridges have been investigated. The main objective of this paper was to discuss the mechanism of failure and the influence of different parameters on PBL shear connectors mechanical properties, including the diameter of transverse rebar, hole spacing and number of holes. The results showed that the failure mode of this type is different from that of conventional concrete specimens. During the failure of specimens, there are few cracks and the overall stiffness still maintain a high level, and reveal that a balance between the size of transverse rebar and the diameter of the hole. In addition, the basic form of the ultimate bearing capacity of existing PBL shearing bonds is summarized, and a new concept of steel fiber shearing in UHPC is proposed. Finally, based on the elastic foundation beam model, the full curve calculation formula of UHPC single-hole PBL shear bond is derived by using Timoshenko beam element. The formula calculation results are in good agreement with the experimental values.