Study on Meso-Fracture Behavior and Fractal Characteristics of Sandstone with Different Particle Sizes under Compression-Shear Test Conditions

Rui Peng,Tong Zhuang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.7

In order to explore the micro-cracking behavior and fractal characteristics of sandstone with different particle sizes under the condition of compression-shear test, this paper studies sandstone with different particle sizes by using high-strength concrete wrapped in cylindrical sandstone test specimen to carry out a compression-shear mechanical test, with the assistance of performing 3D optical scanning on the fracture surface of sandstone after shear failure by using MATLAB to re-establish the three-dimensional shape of the fracture surface. The roughness parameter of the joint surface is introduced to quantitatively calculate the fracture structural plane, which found that the roughness parameter manifests the damage of the structural plane well. The roughness of fracture surface is negatively correlated with the particle size of sandstone, that is, the roughness of fracture surface increases with the decrease of particle size. The fractal dimension of the structural trace line and the sampling area is calculated according to the digital model. Obvious anisotropic characteristics are observed in both dimensions, where the fractal dimension is positively correlated with the particle size of sandstone, in another word, the fractal dimension decreases along with the particle size. The above research results provide experimental support in scientific theory for clarifying the instability mechanism of sandy rock roadway under compression-shear conditions.

Application of Three-dimensional Simulation Technology in Reservoir Regulation and Operational Management

Ruipeng Hu,Zongyi He 보안공학연구지원센터 2013 International Journal of Multimedia and Ubiquitous Vol.8 No.5

An Assessment Model of Owner Safety Management and its Application to Real Estate Projects

Ruipeng Tong,Chunlin Wu,Yang Li,Dongping Fang 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.5

Establishing a scientific and applicative safety management assessment system is crucial in improving safety performance oforganizations. Currently, there are few studies on owners’ safety management assessment systems. Based on the behavioral-basedsafety theory, this paper explores the links among safety management system, safety management behavior, safety management stateand safety performance, which constitute an assessment model that characterizes the features of safety management. It then proposesa safety management indicator system that applies to real estate owners. The applicability and effectiveness of the system is verifiedby a four-year case study with a real estate owner. Relationships between safety management system, safety management behavior,safety management state, and their main impacting factors are obtained. Results indicate that the assessment model makes safetyevaluation clearer and demonstrates significant correlations between different safety management issues. Owners’ safetymanagement system is established and implemented favorably under the safety management assessment indicator system. This paperpresents a profound understanding of safety management assessment, in which the safety management assessment model and theindicator system is applied effectively in practice. To improve safety management level, specific theoretical and practicalimplications lead researchers and practitioners to pay more attention to safety management assessment.

Experimental Investigation on the Effect of Volume Loss on Ground Movements Induced by Tunnelling in Sand

Tianzuo Wang,Ruipeng Wang,Fei Xue,Ningbo Tang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.1

Complex ground conditions or support failures during tunnel construction can lead to high ground loss, which may cause damage to surrounding structures. In this paper, a series model tests are carried out in order to clarify tunnelling-induced ground deformation at high ground loss conditions. The model tunnel in this test is shallowly buried in loose sand and the tunnel volume loss (Vl,t) is set from 4% to 10%. The Vl,t is controlled by a water-filling-drainage system and the ground deformation is monitored by digital image correlation (DIC) system. The results show that the Peck-Gaussian function can be used to fit the settlement data well, and the increase of Vl,t has no significant effect on the width of the settlement trough, while the horizontal displacement can be described by modified empirical method. The width of influence aera caused by tunnelling decreases linearly with depth, and the width near the tunnel crown is about 78% of that on the surface. For loose sand ground, it is the shear band rather than the soil arch that dominates the ground deformation. Furthermore, excavation leads to a volume contraction of the ground, which suggests predictions based on tunnel over-excavation trend to underestimate the ground deformation, and that should be taken seriously in consideration of the safety of the engineering project. This study can provide a better understanding of ground deformation induced by tunnelling.

Development of a Transformation System for the Medicinal Fungus Sanghuangporus baumii and Acquisition of High-Value Strain

Liu Zengcai,Liu Ruipeng,Zou Li 한국균학회 2023 Mycobiology Vol.51 No.3

To further explore the molecular mechanism of triterpenoid biosynthesis and acquire highvalue strain of Sanghuangporus baumii, the Agrobacterium tumefaciens-mediated transformation (ATMT) system was studied. The key triterpenoid biosynthesis-associated gene isopentenyl diphosphate isomerase (IDI) was transformed into S. baumii by ATMT system. Then, the qRT-PCR technique was used to analyze gene transcript level, and the widely targeted metabolomics was used to investigate individual triterpenoid content. Total triterpenoid content and anti-oxidant activity were determined by spectrophotometer. In this study, we for the first time established an efficient ATMT system and transferred the IDI gene into S. baumii. Relative to the wild-type (WT) strain, the IDI-transformant (IT) strain showed significantly higher transcript levels of IDI and total triterpenoid content. We then investigated individual triterpenoids in S. baumii, which led to the identification of 10 distinct triterpenoids. The contents of individual triterpenoids produced by the IT2 strain were 1.76–10.03 times higher than those produced by the WT strain. The triterpenoid production showed a significant positive correlation with the IDI gene expression. Besides, IT2 strain showed better anti-oxidant activity. The findings provide valuable information about the biosynthetic pathway of triterpenoids and provide a strategy for cultivating high-value S. baumii strains.

Reachable Set Estimation for Itô Stochastic Semi-Markovian Jump Systems Against Multiple Time Delays

Shaoxin Sun,Xin Dai,Ruipeng Xi,Yuliang Cai,Xiangpeng Xie,Chunhua Zhang 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.9

The work deals with these issues of stochastic finite-time boundedness (SFTB), reachable set estimation with input-output finite-time mean square stabilization (IO-FTMSS) for multiple state delayed semi-Markovian jump models subject to uncertainties, stochastic process as well as input constraint. There are few attempts to perform related studies. Firstly, a nonlinear passive control mechanism is designed. Then, a closed-loop model could be acquired. Through stochastic Lyapunov function, these problems of SFTB, reachable set estimation with IO-FTMSS could be solved. In addition, these stability conditions are provided in the framework of linear matrix inequalities. These controller gain matrices, meanwhile, can be derived. At last, this availability of this described strategy can be proved through one simulation.

Phase Transitions of Formamidinium Lead Iodide Perovskite under Pressure

Jiang, Shaojie,Luan, Yiliang,Jang, Joon I.,Baikie, Tom,Huang, Xin,Li, Ruipeng,Saouma, Felix O.,Wang, Zhongwu,White, Timothy J.,Fang, Jiye American Chemical Society 2018 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.140 No.42

<P>The pressure-induced structural evolution of formamidinium-based perovskite FAPbI<SUB>3</SUB> was investigated using <I>in situ</I> synchrotron X-ray diffraction and laser-excited photoluminescence methods. Cubic α-FAPbI<SUB>3</SUB> (<I>Pm</I>3̅<I>m</I>) partially and irreversibly transformed to hexagonal δ-FAPbI<SUB>3</SUB> (<I>P</I>6<SUB>3</SUB><I>mc</I>) at a pressure less than 0.1 GPa. Structural transitions of α-FAPbI<SUB>3</SUB> followed the sequence of <I>Pm</I>3̅<I>m</I> → <I>P</I>4/<I>mbm</I> → <I>Im</I>3̅ → partial amorphous during compression to 6.59 GPa, whereas the δ-phase converted to an orthorhombic <I>Cmc</I>2<SUB>1</SUB> structure between 1.26 and 1.73 GPa. During decompression, FAPbI<SUB>3</SUB> recovered the <I>P</I>6<SUB>3</SUB><I>mc</I> structure of the δ-phase as a minor component (∼18 wt %) from 2.41-1.40 GPa and the <I>Pm</I>3̅<I>m</I> structure of the α-phase becomes dominant (∼82 wt %) at 0.10 GPa but with an increased fraction of δ-FAPbI<SUB>3</SUB>. The photoluminescence behaviors from both the α- and δ-forms were likely controlled by radiative recombination at the defect levels rather than band-edge emission during pressure cycling. FAPbI<SUB>3</SUB> polymorphism is exquisitely sensitive to pressure. While modest pressures can engineer FAPbI<SUB>3</SUB>-based photovoltaic devices, irreversible δ-phase crystallization may be a limiting factor and should be taken into account.</P> [FIG OMISSION]</BR>

Remote control system based on the internet and machine vision for tracked vehicles

Shuai Wang,Shubing Zhang,Ruoding Ma,E. Jin,Xinhui Liu,He Tian,Ruipeng Yang 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.3

A remote control system based on the Internet and machine vision is designed in this study for tracked vehicles. The system consists of remote monitoring, remote control, and visual navigation subsystems. The on-board computer receives control commands issued by the monitoring center and controls the speed and steering angle of the tracked vehicles. The front camera collects navigation line information, and the collected image is processed by filtering, gray processing, binarization processing, and interference elimination to obtain the center point coordinates of the navigation line. Proportional-integral-derivative (PID), fuzzy PID, and neural network control algorithms are compared based on the distance and angle deviations of the preview point to control the operation of tracked vehicles through simulation. The Internet remote control system with the fuzzy PID control algorithm is then tested on a tracked vehicle. Experimental results indicate that the trajectory of the tracked vehicle fits the navigation path well.