A Novel Hyperspectral Microscopic Imaging System for Evaluating Fresh Degree of Pork

Yi Xu,Quansheng Chen,Yan Liu,Xin Sun,Qiping Huang,Qin Ouyang,Jiewen Zhao 한국축산식품학회 2018 한국축산식품학회지 Vol.38 No.2

This study proposed a rapid microscopic examination method for pork freshness evaluation by using the self-assembled hyperspectral microscopic imaging (HMI) system with the help of feature extraction algorithm and pattern recognition methods. Pork samples were stored for different days ranging from 0 to 5 days and the freshness of samples was divided into three levels which were determined by total volatile basic nitrogen (TVB-N) content. Meanwhile, hyperspectral microscopic images of samples were acquired by HMI system and processed by the following steps for the further analysis. Firstly, characteristic hyperspectral microscopic images were extracted by using principal component analysis (PCA) and then texture features were selected based on the gray level co-occurrence matrix (GLCM). Next, features data were reduced dimensionality by fisher discriminant analysis (FDA) for further building classification model. Finally, compared with linear discriminant analysis (LDA) model and support vector machine (SVM) model, good back propagation artificial neural network (BP-ANN) model obtained the best freshness classification with a 100 % accuracy rating based on the extracted data. The results confirm that the fabricated HMI system combined with multivariate algorithms has ability to evaluate the fresh degree of pork accurately in the microscopic level, which plays an important role in animal food quality control.

Experimental and Mechanical Behavior of Rubber-Sleeved Group Studs

Yuxuan Chen,Quansheng Yan,Buyu Jia,Xiaolin Yu,Yu Wu,Yufan Luo 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.9

The group studs used in precast steel-concrete composite bridges can reduce the volume of cast-in-place concrete, consequently accelerating the construction process and improving the construction quality. However, the small spacing of the studs in the group studs may result in a decrease in shear strength and ductility, and a nonuniform distribution of shear force at the root of the studs. Hence, rubber-sleeved group studs, whose studs are wrapped by a rubber sleeve at the root, are proposed to redistribute the shear force at the steel–concrete interface and improve the ductility of the shear connector. In this study, four push-out tests were conducted to demonstrate the composite mechanism of rubber-sleeved group studs. Results show that the rubber-sleeved group studs exhibit better ductility than ordinary group studs. Finite element models verified using the test results were also established for parametric analysis. The mechanism analysis shows that the concrete compression regions around stud roots are sufficiently utilized. Based on the parametric analysis, designing suggestions for rubber-sleeved group studs were provided.

Modal identification of Canton Tower under uncertain environmental conditions

Xijun Ye,Quansheng Yan,Weifeng Wang,Xiaolin Yu 국제구조공학회 2012 Smart Structures and Systems, An International Jou Vol.10 No.4

The instrumented Canton Tower is a 610 m high-rise structure, which has been considered as a benchmark problem for structural health monitoring (SHM) research. In this paper, an improved automatic modal identification method is presented based on a natural excitation technique in conjunction with the eigensystem realization algorithm (NExT/ERA). In the proposed modal identification method, damping ratio, consistent mode indicator from observability matrices (CMI_O) and modal amplitude coherence (MAC) are used as criteria to distinguish the physically true modes from spurious modes. Enhanced frequency domain decomposition (EFDD), the data-driven stochastic subspace identification method (SSI-DATA) and the proposed method are respectively applied to extract the modal parameters of the Canton Tower under different environmental conditions. Results of modal parameter identification based on output-only measurements are presented and discussed. User-selected parameters used in those methods are suggested and discussed. Furthermore, the effect of environmental conditions on the dynamic characteristics of Canton tower is investigated.

Modal identification of Canton Tower under uncertain environmental conditions

Ye, Xijun,Yan, Quansheng,Wang, Weifeng,Yu, Xiaolin Techno-Press 2012 Smart Structures and Systems, An International Jou Vol.10 No.4

The instrumented Canton Tower is a 610 m high-rise structure, which has been considered as a benchmark problem for structural health monitoring (SHM) research. In this paper, an improved automatic modal identification method is presented based on a natural excitation technique in conjunction with the eigensystem realization algorithm (NExT/ERA). In the proposed modal identification method, damping ratio, consistent mode indicator from observability matrices (CMI_O) and modal amplitude coherence (MAC) are used as criteria to distinguish the physically true modes from spurious modes. Enhanced frequency domain decomposition (EFDD), the data-driven stochastic subspace identification method (SSI-DATA) and the proposed method are respectively applied to extract the modal parameters of the Canton Tower under different environmental conditions. Results of modal parameter identification based on output-only measurements are presented and discussed. User-selected parameters used in those methods are suggested and discussed. Furthermore, the effect of environmental conditions on the dynamic characteristics of Canton tower is investigated.

Experimental and Numerical Research on Uplift-Restricted and Slip-Permitted Screw-Shaped Connectors

Yuxuan Chen,Quansheng Yan,Xiaolin Yu,Buyu Jia,Yu Wu,Yufan Luo 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.1

Improving mechanical performance of the negative moment regions of continuous composite beams is essential for composite beam bridges. Uplift-restricted and slip-permitted (URSP) screw-shaped connectors can enhance the crack resistance of a concrete slab through free slip between the concrete slab and the steel beam. Furthermore, URSP screw-shaped connectors are more adaptable to the requirements of rapid construction than URSP T-shaped connectors. To investigate the slip and mechanical behavior of URSP screw-shaped connectors, nine push-out tests with various parameters were conducted. In these tests, the thickness of the foam sleeve wrapped outside the screw exerted a highly signifi cant eff ect on free slip performance. A refi ned 3D nonlinear fi nite element model with the foam’s constitutive model was established using ABAQUS. The stress mechanism and failure modes of the FE models were analyzed. Lastly, to estimate the slip performance of URSP screw-shaped connectors, an equation with a simple form was proposed via mechanism analysis and a regression method.

A New Analytical Method for Link Slab Analysis

Yufan Luo,Quansheng Yan,Xiaogang Yue,Buyu Jia,Xiaolin Yu,Yuxuan Chen 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.2

Link slabs have been widely used to reduce the number of expansion joints. However, traditional reinforced concrete link slabs are prone to cracking issues, making it crucial to accurately calculate their internal forces. Currently, the most advanced link slab analysis methods treat the link slab and adjacent span as a rotational spring to simulate their restriction on the girder end rotation. However, this method does not comprehensively consider the link slab's influence, leading to conservative results. To address this issue, this study further considers the influence of girder end deformations on adjacent span, resulting in more accurate calculations of the link slab's internal forces. Additionally, the concept of the girder end rotation reduction coefficient is put forward for the first time, which provides a clearer and more quantified understanding of the link slab's influence. The proposed method is verified by a model test and a site test, which shows a significant improvement in accuracy compared to existing analytical methods. On this basis, a parametric study is conducted to investigate the influence of various parameters on the girder end rotation reduction coefficient, which indicates that span length, girder spacing, and support configuration have the greatest influence.

Statistical Analysis of the Vertical Temperature Gradient of the Web Plate of Steel Box Girder Bridges in Cold Regions

Dandan Hu,Baozhen Yan,Kai Xie,Yancheng Liu,Quansheng Sun 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.9

To understand the actual vertical temperature gradient mode of steel box girder webs in cold regions, nearly 1.5 million data measured for over a year by a comprehensive temperature collection system of a steel box girder bridge in a cold region were used to verify the typicality of the temperature screening samples, and a cluster analysis was performed to verify the statistical symmetry of temperature at the symmetry points of webs on both sides of the bridge. One years’ worth of daily temperature difference data were used to investigate the vertical temperature difference distribution on the web and to determine the probability distribution curve form. After selecting the extreme temperature difference samples, the standard vertical temperature difference of the web was calculated, and the actual vertical temperature gradient model of the steel box girder web was established. Results show that the probability distribution model of temperature at the symmetrical points of webs on both sides of the steel box girder was symmetric. The vertical temperature differences of the web demonstrated significant seasonal changes. The probability distribution of the positive and negative temperature differences can be described based on the sum of two Weibull distributionfunctions. The temperature gradients at all levels in the proposed vertical temperature gradient model were generally greater than the values indicated in the relevant specifications.