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The Boundary Element Method for Ordinary State-Based Peridynamics

Computer Modeling in Engineering & Sciences 2024年第6期139卷 2807-2834页

作者： Xue Liang Linjuan Wang State Key Laboratory for Turbulence and Complex Systems Department of Mechanics and Engineering ScienceCollege of EngineeringPeking UniversityBeijing100871China CAPT-HEDPS and IFSA Collaborative Innovation Center of MoECollege of EngineeringPeking UniversityBeijing100871China School of Astronautics Beihang UniversityBeijing100191China

The peridynamics(Pd),as a promising nonlocal continuum mechanics theory,shines in solving discontinuous *** to now,various numerical methods,such as the peridynamic mesh-free particlemethod(Pd-MPM),peridynamic finite element method(Pd-FEM),and peridynamic boundary element method(Pd-BEM),have been ***-BEM,in particular,outperforms other methods by eliminating spurious boundary softening,efficiently handling infinite problems,and ensuring high computational ***,the existing Pd-BEM is constructed exclusively for bond-based peridynamics(BBPd)with fixed Poisson’s ratio,limiting its applicability to crack propagation problems and scenarios involving infinite or semi-infinite *** this paper,we address these limitations by introducing the boundary element method(BEM)for ordinary state-based peridynamics(OSPd-BEM).Additionally,we present a crack propagationmodel embeddedwithin the framework ofOSPd-BEM to simulate crack *** validate the effectiveness of OSPd-BEM,we conduct four numerical examples:deformation under uniaxial loading,crack initiation in a double-notched specimen,wedge-splitting test,and threepoint bending *** results demonstrate the accuracy and efficiency of OSPd-BEM,highlighting its capability to successfully eliminate spurious boundary softening phenomena under varying Poisson’s ***,OSPdBEMsignificantly reduces computational time and exhibits greater consistencywith experimental results compared to Pd-MPM.

关键词： Ordinary state-based peridynamics boundary element method crack propagation fracture toughness

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Effect of red clover isoflavones on ruminal microbial composition and fermentation in dairy cows

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APPLIEd MICrOBIOLOGY ANd BIOTECHNOLOGY 2025年第1期109卷 1-13页

作者： Bu, Ying Zhang, Xiaoyin Xiong, Zhanbo Li, Kexin Zhang, Shiqi Lin, Miao Zhao, Guoqi Zheng, Nan Wang, Jiaqi Zhao, Shengguo Chinese Acad Agr Sci State Key Lab Anim Nutr & Feeding Inst Anim Sci Beijing 100193 Peoples R China Yangzhou Univ Yangzhou 225000 Peoples R China

red clover isoflavones, particularly biochanin A and formononetin, are known for their benefits in enhancing feed efficiency and nitrogen utilization in ruminants. However, their specific effects on rumen fermentation and microbial diversity remain insufficiently explored. This study investigated the impacts of red clover isoflavones on rumen function and bacterial diversity in dairy cows, utilizing both in vivo and in vitro methodologies. In the in vivo study, 40 Holstein dairy cows were allocated to four groups, each receiving red clover isoflavones at doses of 0, 0.4, 0.8, and 1.6 g/kg. rumen fluid was collected for analysis of fermentation parameters, enzyme activity, and microbial composition through shotgun metagenomic sequencing. Concurrently, an in vitro rumen fermentation trial was conducted to evaluate the effects of biochanin A and formononetin on urea hydrolysis. results from the in vivo experiments showed that red clover isoflavones significantly decreased ammonia nitrogen (NH3-N) concentrations and urease activity in the rumen (P < 0.05). Species level metagenomic analysis indicated a reduced abundance of proteolytic and ureolytic bacteria, such as Prevotella sp002317355 and Treponema_d bryantii_C, with a corresponding increase in cellulolytic bacteria, including ruminococcus_d sp900319075 and ruminococcus_C sp000433635 (P < 0.05). The in vitro trial further demonstrated that biochanin A and formononetin significantly reduced urea decomposition rates (P < 0.05), with biochanin A exerting a more pronounced effect. These findings align with the observed reduction in ureolytic and proteolytic bacteria, along with an increase in cellulolytic bacteria across both trials. In conclusion, biochanin A emerged as the primary active component of red clover isoflavones, modulating urea nitrogen hydrolysis and rumen fermentation. This study substantiates previous findings and highlights the potential of red clover isoflavones for enhancing rumen microbial fermentat

关键词： red clover isoflavones rumen microbiome Fermentation dairy cows Microbial composition

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Staying for food by urban birds: Insights from neural network analysis into adaptive strategies

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ENVIrONMENTAL MANAGEMENT 2025年第4期75卷 896-905页

作者： Liu, Yuran Wei, Yidong Liu, Qiqi Liang, Wei Hainan Normal Univ Coll Life Sci Minist Educ Key Lab Ecol Trop Isl Key Lab Trop Anim & Plant Ecol Hainan Prov Haikou 571158 Peoples R China

Previous work showed that animals have demonstrated remarkable adaptability by actively integrating into urban environments. However, there is no essential difference between urban and rural areas but food availability. The behavioral mechanisms and processes by which animals adapt to cities still require further experimental validation. In this study, field surveys of the flight initiation distance (FId) of black-headed gulls (Chroicocephalus ridibundus) were performed at three scenic sites in Kunming City, Yunnan, southwest china. Our results showed that, within the same area, the FId of black-headed gulls was significantly shorter in areas with increased human activity. Moreover, in areas with earlier human contact, black-headed gulls showed shorter FId. The FId data were further analyzed by a multilayer perceptron regression model with a neural network (ANN-MLP) approach to delineate FId thresholds for black-headed gulls in different human disturbance spots. The analysis revealed that black-headed gulls exhibit a high degree of behavioral flexibility in cities, with food availability playing a key role in increasing the birds' tolerance to humans. These findings highlight the significant impact of human behaviors, such as feeding, on wildlife behavior patterns. Understanding this mechanism is essential for understanding the coexistence of humans and wildlife. The establishment of FId models for black-headed gulls will provide new possibilities and tools for animal behavior research.

关键词： Artificial feeding Behavioral adaptation Flight initiation distance Neural network Urbanization

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The single machine scheduling problem with bio-mathematical fatigue constraints

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INTErnational JOUrNAL OF PrOdUCTION rESEArCH 2025年

作者： Wang, Zhaotong deng, Tianhu Meng, Yize Guo, Han Tsinghua Univ Dept Ind Engn Beijing 100084 Peoples R China Qingzhi Optimizat Beijing Technol Co Ltd Beijing Peoples R China Univ Sci & Technol China Sch Management Hefei Anhui Peoples R China

despite the adverse impacts of occupational fatigue such as accidents and injuries in the manufacturing industry, it has not been systematically examined in the literature on production scheduling. In this paper, we integrate the classic bio-mathematical fatigue prediction model from the brain science literature into the simple single machine scheduling problem with sequence-dependent setup times. Then, we formulate the problem as a mixed-integer linear programming model and propose an adaptive large neighborhood search heuristic. The effectiveness of the heuristic is numerically validated through real cases. Finally, we argue that considering bio-mathematical fatigue prediction can lead to safer production schedules, notably reducing the fatigue working hours in our real case.

关键词： Single machine scheduling bio-mathematical fatigue constraints adaptive large neighborhood search occupational safety and health mixed-integer linear programming

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Investigation of the enhanced cavitation model considering turbulence effects of fuel flow in the injector nozzle holes

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INTErnational JOUrNAL OF ENGINE rESEArCH 2025年第6期26卷 796-810页

作者： Liu, Weilong Zhao, Jianhui Markov, Vladimir Wu, Han Grekhov, Leonid Harbin Engn Univ Coll Power & Energy Engn Dongli Bldg1212 RoomNantong St 145 Harbin Peoples R China Beijing Inst Technol Sch Mech Engn Beijing Peoples R China

The cavitation model is essential in simulating cavitation flow characteristics of injector nozzles, with its accuracy directly impacting simulation precision. This paper developed a quantitative relationship between critical cavitation pressure, turbulent kinetic energy, and shear stress, and introduced a modified cavitation model that considers turbulence effects. A simulation study was conducted on the fuel flow characteristics inside the nozzle of a high-pressure common rail diesel injector with seven nozzle holes. The results indicate that compared to the original model, the cavitation development calculated by the modified model is enhanced at different injection pressures. In terms of axial distribution, cavitation inside the nozzle hole increases, but the impact on cavitation of different intensities varies, with the development of moderate to low-intensity cavitation being promoted, while strong cavitation is inhibited. In terms of radial distribution, the intensity of cavitation on the upper wall inside the nozzle hole increases, which is caused by the higher mass transfer rate near the upper wall at the nozzle hole inlet. As the injection pressure increases from 120 to 240 MPa, the change rate of cavitation volume ratio inside the nozzle holes calculated by the original and modified models increases from 5.1% to 9.7%. It is necessary to use the modified model for the calculations of gas/liquid two-phase flow within the nozzle hole, especially at high injection pressure.

关键词： Turbulent kinetic energy shear stress gas/liquid two-phase flow modification of cavitation model injector nozzles

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H¹-norm Analysis of an Integral-Averaged L1 Method on Nonuniform Time Meshes for a Time-Fractional diffusion Problem

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JOUrNAL OF SCIENTIFIC COMPUTING 2025年第3期103卷

作者： Zheng, Zi-Yun Wang, Yuan-Ming East China Normal Univ Sch Math Sci Key Lab Math & Engn Applicat Shanghai Key Lab Pure Math & Math PracticeMinist Shanghai 200241 Peoples R China

A time-fractional diffusion problem with a Caputo time-fractional derivative of order alpha is an element of (0, 1) is considered, the solution of which is typically weakly singular at the initial time. For this problem, we give an H-1-norm analysis of the stability and convergence of an integral-averaged L1 method on nonuniform time meshes. The averaging of the L1 scheme that we use is known as the L1(+) or L1rline> scheme. A new positive definiteness result for the integral-averaged L1 fractional-derivative operator is established. It improves the previous positive definiteness results in the literature and plays an important role in the analysis of H-1-norm error of the integral-averaged L1 method. The H-1-norm stability holds for the general nonuniform time meshes, while the H-1-norm convergence is proved for the time graded meshes and the H-1-norm convergence order in time is min{3 + alpha, gamma alpha}/2 for all alpha is an element of (0, 1), where gamma >= 1 is the mesh grading parameter. Two full discretization methods using finite differences and finite elements in space are considered. The theoretical results are illustrated by numerical results.

关键词： Time-fractional diffusion problem Integral-averaged L1 method Nonuniform time meshes Positive definiteness H-1-norm stability and convergence

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ON THE EMPTY BALLS OF A CrITICAL Or SUBCrITICAL BrANCHING rANdOM WALK

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Acta Mathematica Scientia 2024年第5期44卷 2051-2072页

作者： Shuxiong ZHANG Jie XIONG School of Mathematics and Statistics Anhui Normal UniversityWuhu241002China Department of Mathematics and SUSTech International Center for Mathematics Southern University of Science and TechnologyShenzhen518055China

Let{Z_(n)}_(n)≥0 be a critical or subcritical d-dimensional branching random walk started from a Poisson random measure whose intensity measure is the Lebesugue measure on r^(d).denote by r_(n):=sup{u>0:Z_(n)({x∈r^(d):∣x∣radius of the largest empty ball centered at the origin of Z_(n).In this work,we prove that after suitable renormalization,rn converges in law to some non-degenerate distribution as n→∞.Furthermore,our work shows that the renormalization scales depend on the offspring law and the dimension of the branching random *** completes the results of révész[13]for the critical binary branching Wiener process.

关键词： empty ball dimension branching random walk super-Brownian motion

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An original feature retention deconvolution algorithm and its application to bearing fault diagnosis

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MEASUrEMENT SCIENCE ANd TECHNOLOGY 2025年第1期36卷 015052-015052页

作者： Cheng, Lei Yang, Gang Southwest Jiaotong Univ Tangshan Res Inst Tangshan 063000 Peoples R China Southwest Jiaotong Univ Coll Mech Engn Chengdu 610036 Peoples R China

Traditional blind deconvolution algorithms perform well in estimating the repetition rate of impulses within signals;however, they fall short in preserving the original features of the signal. In engineering applications, particularly for cyclic impulse signals, maintaining signal fidelity is as crucial as accurately estimating impulse counts, making pure impulse count estimation insufficient for practical needs. To address this limitation, we propose a novel deconvolution algorithm-maximum correlation Pearson fidelity coefficient deconvolution (MCPSFd). This method constructs an objective function based on two key metrics: the correlation Pearson coefficient (CPC), which quantifies the periodicity of impulses, and the signal fidelity coefficient (SFC), which measures the similarity between the original and recovered signals. By combining CPC and SFC, we introduce a new objective function, termed the correlated Pearson fidelity factor (CPSF), which simultaneously considers both the number of impulses and the original characteristics of the filtered signal without introducing redundant parameters. The MCPSFd algorithm is derived by maximizing the CPSF function. Extensive experiments on simulated and measured bearing signals demonstrate that the proposed method significantly outperforms existing deconvolution algorithms in recovering periodic impulses and minimizing signal distortion.

关键词： blind deconvolution fault diagnosis correlation Pearson correlation coefficient signal fidelity coefficient maximum correlation Pearson coefficient fidelity deconvolution

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Quality difference Analysis Among Soy Whey Produced by different Processing Methods

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FLAVOUr ANd FrAGrANCE JOUrNAL 2025年第0期

作者： Yang, Minhui Zhu, danshi Zhang, Xuan Huo, dafei Liu, Jun Zhou, dayu Liu, He Bohai Univ Coll Food Sci & Technol Natl & Local Joint Engn Res Ctr Storage Jinzhou Peoples R China Liaoning Douhua Tianbao Food Technol Co Ltd Shenyang Peoples R China Shandong Yuwang Ecog Food Ind Co Ltd Yucheng Peoples R China

The objective of this study was to analyse the difference in sensory flavour and volatile compounds among the three processing methods of soy whey, as well as to establish an evaluation model representing the correlation between sensory flavour and volatile compounds. The results showed that the soy whey produced by the boiling-to-filtering method (BFM) exhibited a higher total soluble solid (TSS) content and total flavonoid content (TFC) compared to that of the repeated boiling-to-filtering method (rBFM) and the filtering-to-boiling method (FBM), while rBFM soy whey showed a higher total protein content (TPC). The sensory analysis showed that the FBM soy whey exhibited an intense beany flavour and grease odour. The SPME/GC-MS results showed that FBM soy whey exhibited more categories and higher contents of flavour compounds, particularly for alcohols and aldehydes. 1-Octen-3-ol, n-hexanol, hexanal and nonanal were the main volatile compounds influencing soy whey with different processing methods. The evaluation model revealed that the beany flavour was close to FBM soy whey and highly correlated with 1-octen-3-ol, n-hexanol, hexanal, heptanal and 2-ethyl furan. (E, E)-2,4-Heptadienal, (E, E)-2,4-nonadienal and octanal were close to FBM and highly correlated with grease and bean fragrance. decanal, ethyl caproate and ethyl caprylate were highly correlated with the floral aroma and close to FBM soy whey. Sweet and fruity aromas were associated with rBFM soy whey and highly correlated with 3-methyl butanal, (E)-2-nonenal and nonanal. The milk aroma was close to BFM soy whey and highly correlated with 2-ethylfuran, decanal, ethyl caprylate and ethyl caproate. Overall, rBFM and BFM soy whey contained higher levels of protein and flavonoids and exhibited less beany flavour, potentially offering greater nutritional value. In contrast, the FBM soy whey exhibited a higher content of volatile flavour compounds, especially 1-octen-3-ol, n-hexanol, hexanal and 2-ethyl furan.

关键词： OPLS-dA quantitative descriptive analysis sensory flavour soy whey volatile compounds

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Otud6a Knockout Leads to Male Subfertility in Mice

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MOLECULAr rEPrOdUCTION ANd dEVELOPMENT 2025年第3期92卷 e70022页

作者： Yang, Fulin Wang, Zhuangfei Li, danyang Gao, Fei Hou, Xiaohui Zunyi Med Univ Dept Basic Med Sci Zunyi Peoples R China Lanzhou Univ Sch Life Sci Gansu Prov Key Lab Gene Editing Breeding Lanzhou Peoples R China Chinese Acad Sci Inst Zool State Key Lab Stem Cell & Reprod Biol Beijing Peoples R China Univ Chinese Acad Sci Beijing Peoples R China

Ovarian tumor ubiquitinating 6A (OTUd6A) is a deubiquitinating enzyme whose aberrant expression has been linked to various diseases, including inflammation and prostate cancer. research indicates that deubiquitinating enzymes (dUBs) play a significant role in spermatogenesis in mice. However, the role of OTUd6A in spermatogenesis remains unclear. To investigate the function of OTUd6A in mouse spermatogenesis, we generated Otud6a-knockout mice using the CrISPr/Cas9 system. Our results showed that OTUd6A is predominantly expressed in the testis and localized to the cytoplasm of spermatogonia and spermatocytes. Although no significant differences were observed in testicular size or morphology between Otud6a-knockout and wild-type mice, the knockout mice exhibited increased germ cell apoptosis, decreased epididymal sperm counts, abnormalities in sperm motility and subfertility. These findings indicate that Otud6a-knockout leads to male subfertility in mice.

关键词： apoptosis OTUd6A spermatogenesis subfertility

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