Experimental and numerical study on pre-peak cyclic shear mechanism of artificial rock joints

Xinrong Liu,Yongquan Liu,Yuming Lu,Miaomiao Kou 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.74 No.3

The pre-peak cyclic shear mechanism of two-order asperity degradation of rock joints in the direct shear tests with static constant normal loads (CNL) are investigated using experimental and numerical methods. The laboratory testing rock specimens contains the idealized and regular two-order triangular-shaped asperities, which represent the specific geometrical conditions of natural and irregular waviness and unevenness of rock joint surfaces, in the pre-peak cyclic shear tests. Three different shear failure patterns of two-order triangular-shaped rock joints can be found in the experiments at constant horizontal shear velocity and various static constant normal loads in the direct and pre-peak cyclic shear tests. The discrete element method is adopted to simulate the pre-peak shear failure behaviors of rock joints with two-order triangular-shaped asperities. The rock joint interfaces are simulated using a modified smooth joint model, where microscopic scale slip surfaces are applied at contacts between discrete particles in the upper and lower rock blocks. Comparing the discrete numerical results with the experimental results, the microscopic bond particle model parameters are calibrated. Effects of cyclic shear loading amplitude, static constant normal loads and initial waviness asperity angles on the pre-peak cyclic shear failure behaviors of triangular-shaped rock joints are also numerically investigated.

Sanshool from Zanthoxylum L. Induces Apoptosis in Human Hepatocarcinoma HepG2 Cells

Yuming You,Min Zhou,Hongjia Lu,Gasper Gerald Shirima,Yajiao Cheng,Xiong Liu 한국식품과학회 2015 Food Science and Biotechnology Vol.24 No.6

Anti-proliferation and apoptosis induction activities of sanshool isolated from Zanthoxylum bungeanum (Rutaceae) in HepG2 cells were investigated. Cell proliferation was analyzed using MTT assays. Apoptotic bodies were observed under scanning electron microscopy. Nucleus staining using dichlorofluorescin diacetate (DAPI) was performed and the mitochondrial membrane potential (ΔΨm) using rhodamine-123 was observed under laser confocal microscopy. Sanshool inhibited cell proliferation in both a dose and time-dependent manner. The anti-proliferation activity was stimulated with apoptosis induction based on an increase in the sub-G1 cell population, DNA fragmentation, and typical apoptotic morphological changes. Sanshool also disrupted ΔΨm and up-regulated mRNA and protein expressions of p53 and caspase-3. Sanshool induced apoptosis via a mitochondrion-dependent pathway. Thus, sanshool is a potential anticancer medicine.

GENERALIZED YANG'S CONJECTURE ON THE PERIODICITY OF ENTIRE FUNCTIONS

Liu, Kai,Wei, Yuming,Yu, Peiyong Korean Mathematical Society 2020 대한수학회보 Vol.57 No.5

On the periodicity of transcendental entire functions, Yang's Conjecture is proposed in [6, 13]. In the paper, we mainly consider and obtain partial results on a general version of Yang's Conjecture, namely, if f(z)ⁿf^(k)(z) is a periodic function, then f(z) is also a periodic function. We also prove that if f(z)ⁿ+f^(k)(z) is a periodic function with additional assumptions, then f(z) is also a periodic function, where n, k are positive integers.

Analysis of Clostridium Cluster I Community Diversity in Pit Mud Used in Manufacture of Chinese Luzhou-flavor Liquor

Maoke Liu,Ke Zhao,Yuming Tang,Daoqun Ren,Wanchun Yao,Xinhui Tian,Xinyu Zhang,Bin Yi,Bo Deng 한국식품과학회 2015 Food Science and Biotechnology Vol.24 No.3

Chinese Luzhou-flavor liquor is prepared using distillation of mixed, fermented grains, such as sorghum and rice. Fermentation occurs in cellars lined with pit mud containing microbes. The identity and community diversity of bacteria in pit mud of fermentation cellars contributes to the aromatic compounds of the liquor. In order to determine the contribution of genus Clostridium to this fermentation, the community diversity of Clostridium cluster I in pit mud of different cellar ages (1, 50, 100, and 400 years) was investigated based on denaturing gradient gel electrophoresis followed by 16S rRNA sequencing. Differences in the community structure within pit mud depended on wall and bottom layer cellar locations. A better understanding of the role of Clostridium in Luzhou-flavor liquor manufacture will be useful.

Study on Model Test of High Slope Supported by Micro-steel Pipe Piles

( Xueling Liu ),( Yuming Men ) 대한지질공학회 2019 대한지질공학회 학술발표회논문집 Vol.2019 No.2

The slope excavation is a commonly-used technology to expand the land space in the urban construction in the mountainous region. Due to the existence of potential slip surfaces developed in high-steep slopes, cutting will destroy initial equilibrium state within the slope body and cause a landslide. It is necessary to pre-support the slope before cutting to enhance the stability of the slope. In this research, a physical model test of using the micro-steel pipe piles to support the high and steep slope was carried out to make a comparison of the slope stabilities and deformation before and after installing the micro-steel pipe piles reinforcement. Test results show the safety factor is 0.93 in the case without using micro-steel pipe piles, and the slope failure occurred along the preset sliding surface after the slope cutting completed. For the slope supported by micro-steel pipe piles, the safety factor increased to 1.5 and no sliding trace and deformation was observed after the slope cutting. The result shows that the micro-steel pipe piles were effective in supporting the high and steep slope and restraining the slope movement, thus enhancing the stability of slope. This study provides an engineering practice for the supporting design of the high and steep slope.

Model-based Visual Servoing for Automatic Docking System of Circular Symmetrical Target with Large Displacement

Tingting Wang,Yuming Zhang,Bo Liu 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.4

In this paper, a model-based visual servoing strategy with dual cameras is proposed for a circular symmetrical target with large displacement. The automatic docking system is composed of the fast-moving stage and the position-based visual servoing (PBVS) control stage, which enables a fast, accurate and stable docking task. A simplified stereo matching method is used in the fast-moving stage, and the CAD model-based tracking method with virtual visual servoing (VVS) method is applied in the PBVS control stage to estimate and update the current pose of the circular symmetrical docking target. Experiments of a robotic docking system validate the effectiveness, precision and flexibility of this strategy. The Root Mean Square errors of the docking results are less than 0.5 millimeters in translation and 0.1 degrees in rotation, and the average time for the whole docking task is no more than 1 minutes.

Current effects on global motions of a floating platform in waves

Shen, Meng,Liu, Yuming Techno-Press 2017 Ocean systems engineering Vol.7 No.2

The purpose of this paper is to understand and model the slow current (~2 m/s) effects on the global response of a floating offshore platform in waves. A time-domain numerical simulation of full wave-current-body interaction by a quadratic boundary element method (QBEM) is applied to compute the hydrodynamic loads and motions of a floating body under the combined influence of waves and current. The study is performed in the context of linearized potential flow theory that is sufficient in understanding the leading-order current effect on the body motion. The numerical simulations are validated by quantitative comparisons of the hydrodynamic coefficients with the WAMIT prediction for a truncated vertical circular cylinder in the absence of current. It is found from the simulation results that the presence of current leads to a loss of symmetry in flow dynamics for a tension-leg platform (TLP) with symmetric geometry, resulting in the coupling of the heave motion with the surge and pitch motions. Moreover, the presence of current largely affects the wave excitation force and moment as well as the motion of the platform while it has a negligible influence on the added mass and damping coefficients. It is also found that the current effect is strongly correlated with the wavelength but not frequency of the wave field. The global motion of a floating body in the presence of a slow current at relatively small encounter wave frequencies can be satisfactorily approximated by the response of the body in the absence of current at the intrinsic frequency corresponding to the same wavelength as in the presence of current. This finding has a significant implication in the model test of global motions of offshore structures in ocean waves and currents.

Optimum design of miniature platforms for marginal fields

Miao, Sha,Liu, Yuming,Yue, Dick K.P. Techno-Press 2021 Ocean systems engineering Vol.11 No.2

Motivated by many recent discoveries of marginal fields in deep water, this paper presents a novel and economical design concept of a minimal floating platform with around 10,000 cubic tons in displacement. The concept characterizes a simple hull geometry and an excellent seakeeping behavior. It incorporates a damping plate at the keel on the basis of a spar-like floater. The design procedure is explained and illustrated. The paper also describes a new design methodology that is capable of efficiently evaluating the seakeeping performance of the platforms with the viscous damping effect included. We integrate this methodology into an Evolutionary Algorithm (EA) to conduct a multi-objective optimization for our novel design. The hull shape is optimized by minimizing the heave motion in waves without sacrificing the cost in construction and installation. Several potential geometric configurations are considered. The optimization results provide a wealth of information that can be used to support practical design decisions.

The development model of PT Visionet Internasional (OVO) in Indonesia

Yuhang Xia,Yuming Liu,최명철,Chuijie Meng,김한얼 국제문화기술진흥원 2023 International Journal of Advanced Culture Technolo Vol.11 No.2

OVO is a digital platform that provides simple payments and smart financial services, as well as one of the largest digital payment platforms in Indonesia. It has wide coverage and security when making payments, and supports multiple settlement currencies. The purpose of this study is to explore the history, business model, and future strategic direction of OVO, an Indonesian e-wallet. To date, OVO has built its own mobile payment ecosystem covering a wide range of consumer scenarios including e-commerce, travel, offline shopping and finance. And it supports mobile banking, online banking, debit cards or selected partner merchants. Its three largest transaction categories are in the transportation, retail and e-commerce sectors. With over 110 million consumers and 1.3 million merchant users, it is one of the dominant e-wallets in Indonesian market and has become the country's e-payment market leader. OVO eWallet's ‘One Card’ model offers convenience and choice for users, thus contributing to the rapid growth of OVO eWallet. And OVO eWallet competes fiercely with other competitors, but OVO eWallet continues to grow in terms of the number of users and market share. Finally, this study analyzes the strategic goals and plans of OVO eWallet, predicts its future direction. OVO eWallet has a huge success, but there are still competition and challenges to face.

Evaluating and predicting net energy value of wheat and wheat bran for broiler chickens

Ning Ran,Cheng Zichen,Liu Xingbo,Ban Zhibin,Guo Yuming,Nie Wei 아세아·태평양축산학회 2022 Animal Bioscience Vol.35 No.11

Objective: It is crucial to accurately determine the net energy (NE) values of feed ingredients because the NE system is expected to be applied to the formulation of broilers feed. The NE values of 5 wheat and 5 wheat brans were determined in 12-to 14-day old Arbor Acres (AA) broilers with substitution method and indirect calorimetry method. Methods: A total of 12 diets, including 2 reference diets (REF) and 10 test diets (5 wheat diets and 5 wheat bran diets) containing 30% of test ingredients, were randomly fed to 864 male AA birds with 6 replicates of 12 birds per treatment. These birds were used to determine metabolizable energy (ME) (8 birds per replicate) in the chicken house and NE (4 birds per replicate) in the chamber respectively at the same time. After a 4-d dietary and environment adaptation period, growth performance, energy values, energy balance and energy utilization were measured during the following 3 d. Multiple linear regression analyses were further performed to generate prediction equations for NE values based on the chemical components and ME values. The NE prediction equation were also validated on another wheat diet and another wheat bran diet with high correlation (r = 0.98, r = 0.75). Results: The NE values of 5 wheat and 5 wheat bran samples are 9.34, 10.02, 10.27, 11.33, and 10.49 MJ/kg, and 5.37, 5.17, 4.87, 5.06, and 4.88 MJ/kg DM, respectively. The equation with the best fit were NE = 1.968AME–0.411×ADF–14.227 (for wheat) and NE = –0.382×CF –0.362×CP–0.244×ADF+20.870 (for wheat bran). Conclusion: The mean NE values of wheat and wheat bran are 10.29 and 5.07 MJ/kg DM in AA broilers. The NE values of ingredients could be predicted by their chemical composition and energy value with good fitness. Objective: It is crucial to accurately determine the net energy (NE) values of feed ingredients because the NE system is expected to be applied to the formulation of broilers feed. The NE values of 5 wheat and 5 wheat brans were determined in 12-to 14-day old Arbor Acres (AA) broilers with substitution method and indirect calorimetry method.Methods: A total of 12 diets, including 2 reference diets (REF) and 10 test diets (5 wheat diets and 5 wheat bran diets) containing 30% of test ingredients, were randomly fed to 864 male AA birds with 6 replicates of 12 birds per treatment. These birds were used to determine metabolizable energy (ME) (8 birds per replicate) in the chicken house and NE (4 birds per replicate) in the chamber respectively at the same time. After a 4-d dietary and environment adaptation period, growth performance, energy values, energy balance and energy utilization were measured during the following 3 d. Multiple linear regression analyses were further performed to generate prediction equations for NE values based on the chemical components and ME values. The NE prediction equation were also validated on another wheat diet and another wheat bran diet with high correlation (r = 0.98, r = 0.75).Results: The NE values of 5 wheat and 5 wheat bran samples are 9.34, 10.02, 10.27, 11.33, and 10.49 MJ/kg, and 5.37, 5.17, 4.87, 5.06, and 4.88 MJ/kg DM, respectively. The equation with the best fit were NE = 1.968AME–0.411×ADF–14.227 (for wheat) and NE = –0.382×CF–0.362×CP–0.244×ADF+20.870 (for wheat bran).Conclusion: The mean NE values of wheat and wheat bran are 10.29 and 5.07 MJ/kg DM in AA broilers. The NE values of ingredients could be predicted by their chemical composition and energy value with good fitness.