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Performances of fissured red sandstone after thermal treatment with constant-amplitude and low-cycle impacts

Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 561-587页

作者： Yongjun Chen Tubing Yin P.G.Ranjith Xibing Li Qiang Li Dengdeng Zhuang school of Resources and Safety Engineering Central South UniversityChangsha410083China Department of Civil Engineering Monash UniversityMelbourne3800Australia oulu mining school University of OuluOuluFI-90014Finland

In the engineering practices,it is increasingly common to encounter fractured rocks perturbed by temperatures and frequent dynamic *** this paper,the dynamic behaviors and fracture characteristics of red sandstone considering temperatures(25℃,200℃,400℃,600℃,and 800℃)and fissure angles(0°,30°,60°,and 90°)were evaluated under constant-amplitude and low-cycle(CALC)impacts actuated by a modified split Hopkinson pressure bar(SHPB)***,fracture morphology and second-order statistics within the grey-level co-occurrence matrix(GLCM)were examined using scanning electron microscopy(SEM).Meanwhile,the deep analysis and discussion of the mechanical response were conducted through the synchronous thermal analyzer(STA)test,numerical simulations,one-dimensional stress wave theory,and material *** multiple regression models between response variables and interactive effects of independent variables were established using the response surface method(RSM).The results demonstrate the fatigue strength and life diminish as temperatures rise and increase with increasing fissure angles,while the strain rate exhibits an inverse ***,the peak stress intensification and strain rate softening observed during CALC impact exhibit greater prominence at increased fissure *** failure is dominated by tensile damage with concise evolution paths and intergranular cracks as well as the compressor-crushed zone which may affect the failure mode after 400℃.The second-order statistics of GLCM in SEM images exhibit a considerable dependence on the ***,thermal damage dominated by thermal properties controls the material structure and wave impedance and eventually affects the incident wave *** tensile wave reflected from the fissure surface is the inherent mechanism responsible for the angle effect exhibited by the fatigue strength and ***,the peak stress intensification and strain rate softening during impact are determ

关键词： Red sandstone Temperature Fissure Constant-amplitude and low-cycle(CALC) impact Fatigue failure Response surface method(RSM)

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Predicting dynamic compressive strength of frozen-thawed rocks by characteristic impedance and data-driven methods

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2591-2606页

作者： Shengtao Zhou Zong-Xian Zhang Xuedong Luo Yifan Huang Zhi Yu Xiaowei Yang Faculty of Engineering China University of GeosciencesWuhan430074China oulu mining school University of OuluOulu90570Finland Zijin school of Geology and mining Fuzhou UniversityFuzhou350116China Department of Earth Science&Engineering Imperial College LondonLondonSW72AZUK

In cold regions,the dynamic compressive strength(DCS)of rock damaged by freeze-thaw weathering significantly influences the stability of rock ***,testing the dynamic strength under freeze-thaw weathering conditions is often both time-consuming and ***,this study considers the effect of characteristic impedance on DCS and aims to quickly determine the DCS of frozen-thawed rocks through the application of machine-learning ***,a database of DCS for frozen-thawed rocks,comprising 216 rock specimens,was *** external load parameters(freeze-thaw cycle number,confining pressure,and impact pressure)and two rock parameters(characteristic impedance and porosity)were selected as input variables,with DCS as the predicted *** research optimized the kernel scale,penalty factor,and insensitive loss coefficient of the support vector regression(SVR)model using five swarm intelligent optimization algorithms,leading to the development of five hybrid *** addition,a statistical DCS prediction equation using multiple linear regression techniques was *** performance of the prediction models was comprehensively evaluated using two error indexes and two trend indexes.A sensitivity analysis based on the cosine amplitude method has also been *** results demonstrate that the proposed hybrid SVR-based models consistently provided accurate DCS *** these models,the SVR model optimized with the chameleon swarm algorithm exhibited the best performance,with metrics indicating its effectiveness,including root mean square error(RMSE)﹦3.9675,mean absolute error(MAE)﹦2.9673,coefficient of determination(R^(2))﹦0.98631,and variance accounted for(VAF)﹦*** suggests that the chameleon swarm algorithm yielded the most optimal results for enhancing SVR ***,impact pressure and characteristic impedance emerged as the two most influential parameters in DCS *** research is

关键词： Freeze-thaw cycle Characteristic impedance Dynamic compressive strength Machine learning Support vector regression

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基于注汞法的液冷花岗岩微观特性实验研究

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Journal of Central South University 2024年第1期31卷 169-181页

作者：尹土兵苏巨振庄登登李夕兵 school of Resources and Safety Engineering Central South UniversityChangsha 410083China oulu mining school University of OuluFI-90014 OuluFinland

在开采高温储层的过程中,微观特征变化重要影响深部热储层人工裂隙网络的建立。因此,研究该过程中微观特征的变化对深部地热能的安全高效开采具有重要意义。采用液体冷却(包括酸冷却和水冷却)处理高温花岗岩,模拟向高温储层注酸情况,以... 详细信息

在开采高温储层的过程中,微观特征变化重要影响深部热储层人工裂隙网络的建立。因此,研究该过程中微观特征的变化对深部地热能的安全高效开采具有重要意义。采用液体冷却(包括酸冷却和水冷却)处理高温花岗岩,模拟向高温储层注酸情况,以获取相应条件下的花岗岩试样。随后,使用扫描电子显微镜-能量散射谱(SEM-EDS)和高压注汞法对样品进行测试。SEM-EDS结果显示,水冷却几乎不会影响元素的组成,酸冷却导致氧、硅和金属元素减少。在两种情况下,都观察到了孔隙和裂缝的形成。此外,与水冷却相比,酸冷却的样品表面更加不平整、疏松和粗糙。注汞法测试结果显示,随着处理温度的升高,液冷花岗岩样品的孔隙率、孔隙体积和比表面积有增加,但分形维数呈相反的趋势。研究结果表明,与水冷却相比,酸冷却条件对花岗岩的腐蚀作用使各项参数的变化更加显著,在酸冷却过程中产生更多的孔隙,提供更好的运输空间,使孔隙结构的复杂性降低。在高温储层的地热能有效提取方面,酸冷却具有更大应用潜力。

关键词：孔隙结构微观结构液体冷却土酸溶液注汞法花岗岩分形理论

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高压电脉冲刺激对于热处理花岗岩影响的实验研究

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Journal of Central South University 2024年第5期31卷 1526-1541页

作者：尹土兵刘程辉庄登登李夕兵 school of Resources and Safety Engineering Central South UniversityChangsha 410083China oulu mining school University of OuluOulu FI-90014Finland

高压电脉冲技术作为一种环保、可控、高效的破碎坚硬岩石的方法,其潜在应用场景值得进一步深入发掘。本文研究了高压电脉冲诱导干热岩产生预损伤和劣化方法的效果。对热处理后花岗岩薄片试样施加了不同峰值电压的高压电脉冲刺激,探讨了... 详细信息

高压电脉冲技术作为一种环保、可控、高效的破碎坚硬岩石的方法,其潜在应用场景值得进一步深入发掘。本文研究了高压电脉冲诱导干热岩产生预损伤和劣化方法的效果。对热处理后花岗岩薄片试样施加了不同峰值电压的高压电脉冲刺激,探讨了高压电脉冲对于热处理花岗岩的影响。此外,还研究了初始温度对高压电脉冲刺激花岗岩的影响。结果表明:当外加峰值电压超过96 kV时,热处理花岗岩试样发生贯穿性的破裂,峰值电压越高,贯穿裂纹网络越复杂。当电压从96 kV增加到144kV时,花岗岩试样的微裂纹密度从8.63 mm/mm^(2)增加到13.26 mm/mm^(2)。随着热处理温度的升高,花岗岩发生电击穿的难度逐渐降低。在120 kV电脉冲放电刺激3次后,所有热处理温度高于400℃的花岗岩试样均能发生贯穿破裂。高压电脉冲刺激造成花岗岩产生的最大损伤发生在300~400℃的温度区间内。通过扫描电子显微镜观察到,随着试样处理温度的升高,内部孔隙和裂缝的发育情况逐渐加剧,孔隙大小、裂缝宽度和深度也随之增加。这项研究有望为建造干热岩人工储层提供新的见解。

关键词：干热岩高压电脉冲破岩技术温度断裂模式岩石结构

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Temperature-jump tensile tests to induce optimized TRIP/TWIP effect in a metastable austenitic stainless steel

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International Journal of Minerals,Metallurgy and Materials 2024年第9期31卷 2025-2036页

作者： Mohammad Javad Sohrabi Hamed Mirzadeh Saeed Sadeghpour Abdol Reza Geranmayeh Reza Mahmudi school of Metallurgy and Materials Engineering College of EngineeringUniversity of Tehran14395-515TehranIran Centre for Advanced Steels Research Materials and Mechanical EngineeringUniversity of Oulu90014 OuluFinland

In the present work,plastic deformation mechanisms were initially tailored by adjusting the deformation temperature in the range of 0 to 200℃ in AISI 304L austenitic stainless steel,aiming to optimize the strength-ductility *** was shown that the combined twinning-induced plasticity(TWIP)/transformation-induced plasticity(TRIP)effects and a wider strain range for the TRIP effect up to higher strains by adjusting the deformation temperature are good strategies to improve the strength-ductility synergy of this metastable stainless *** this regard,by consideration of the observed temperature-dependency of plastic deformation,the controlled sequence of TWIP and TRIP effects for archiving superior strength-ductility trade-off was intended by the pre-designed temperature jump tensile ***,the optimum tensile toughness of 846 MJ/m^(3) and total elongation to 133% were obtained by this strategy via exploiting the advantages of the TWIP effect at 100℃ and the TRIP effect at 25℃ at the later stages of the ***,a deformation-temperature-transformation(DTT)diagram was developed for this metastable ***,based on work-hardening analysis,it was found that the main phenomenon constraining further improvement in the ductility and strengthening was the yielding of the deformation-induced α′-martensite.

关键词： metastable stainless steels transformation-induced plasticity twinning-induced plasticity stacking fault energy mechanical properties

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高压电脉冲刺激对于热处理花岗岩影响的实验研究（英文）

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Journal of Central South University 2024年

作者：尹土兵刘程辉庄登登李夕兵 school of Resources and Safety Engineering Central South University oulu mining school University of Oulu

高压电脉冲技术作为一种环保、可控、高效的破碎坚硬岩石的方法，其潜在应用场景值得进一步深入发掘。本文研究了高压电脉冲诱导干热岩产生预损伤和劣化方法的效果。对热处理后花岗岩薄片试样施加了不同峰值电压的高压电脉冲刺激，探讨... 详细信息

高压电脉冲技术作为一种环保、可控、高效的破碎坚硬岩石的方法，其潜在应用场景值得进一步深入发掘。本文研究了高压电脉冲诱导干热岩产生预损伤和劣化方法的效果。对热处理后花岗岩薄片试样施加了不同峰值电压的高压电脉冲刺激，探讨了高压电脉冲对于热处理花岗岩的影响。此外，还研究了初始温度对高压电脉冲刺激花岗岩的影响。结果表明：当外加峰值电压超过96 kV时，热处理花岗岩试样发生贯穿性的破裂，峰值电压越高，贯穿裂纹网络越复杂。此外，通过制备光学薄片的手段在一定程度上证实了高压电脉冲刺激增加花岗岩微裂纹发育情况的有效性。当电压从96 kV增加到144 kV时，花岗岩试样的微裂纹密度从8.63 mm/mm2增加到13.26 mm/mm2。随着热处理温度的升高，花岗岩发生电击穿的难度逐渐降低。在120 kV电脉冲放电刺激三次后，所有热处理温度高于400℃的花岗岩试样均能发生贯穿破裂。高压电脉冲刺激造成花岗岩产生的最大损伤发生在300-400℃的温度区间内。通过扫描电子显微镜观察到，随着试样处理温度的升高，内部孔隙和裂缝的发育情况逐渐加剧，孔隙大小、裂缝宽度和深度也随之增加。这项研究有望为建造干热岩人工储层提供新的见解。

关键词：干热岩高压电脉冲破岩技术温度断裂模式岩石结构

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Data Driven Vibration Control:A Review

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IEEE/CAA Journal of Automatica Sinica 2024年第9期11卷 1898-1917页

作者： Weiyi Yang Shuai Li Xin Luo Chongqing Institute of Green and Intelligent Technology Chinese Academy of SciencesChongqing 400714 Chongqing school University of Chinese Academy of SciencesChongqing 400714China Faculty of Information Technology and Electrical Engineering University of OuluOulu 90570 VTT-Technology Research Center of Finland Oulu 90570Finlan College of Computer and Information Science Southwest UniversityChongqing 400715China

With the ongoing advancements in sensor networks and data acquisition technologies across various systems like manufacturing,aviation,and healthcare,the data driven vibration control(DDVC)has attracted broad interests from both the industrial and academic *** shaping(IS),as a simple and effective feedforward method,is greatly demanded in DDVC *** convolves the desired input command with impulse sequence without requiring parametric dynamics and the closed-loop system structure,thereby suppressing the residual vibration *** on a thorough investigation into the state-of-the-art DDVC methods,this survey has made the following efforts:1)Introducing the IS theory and typical input shapers;2)Categorizing recent progress of DDVC methods;3)Summarizing commonly adopted metrics for DDVC;and 4)Discussing the engineering applications and future trends of *** doing so,this study provides a systematic and comprehensive overview of existing DDVC methods from designing to optimizing perspectives,aiming at promoting future research regarding this emerging and vital issue.

关键词： Data driven vibration control(DDVC) data science designing method feedforward control industrial robot input shaping optimizing method residual vibration

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Interplay between temperature-dependent strengthening mechanisms and mechanical stability in high-performance austenitic stainless steels

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International Journal of Minerals,Metallurgy and Materials 2024年第10期31卷 2182-2188页

作者： Mohammad Javad Sohrabi Hamed Mirzadeh Saeed Sadeghpour Milad Zolfipour Aghdam Abdol Reza Geranmayeh Reza Mahmudi school of Metallurgy and Materials Engineering College of EngineeringUniversity of Tehran14395-515 TehranIran Centre for Advanced Steels Research Materials and Mechanical EngineeringUniversity of Oulu90014 OuluFinland Department of Mechanical Engineering College of EngineeringUniversity of Tehran14395-515 TehranIran

The effects of deformation temperature on the transformation-induced plasticity(TRIP)-aided 304L,twinning-induced plasti-city(TWIP)-assisted 316L,and highly alloyed stable 904L austenitic stainless steels were compared for the first time to tune the mechan-ical properties,strengthening mechanisms,and strength-ductility *** this purpose,the scanning electron microscopy(SEM),electron backscattered diffraction(EBSD),X-ray diffraction(XRD),tensile testing,work-hardening analysis,and thermodynamics calcu-lations were *** induced plasticity effects led to a high temperature-dependency of work-hardening behavior in the 304L and 316L stainless *** the deformation temperature increased,the metastable 304L stainless steel showed the sequence of TRIP,TWIP,and weakening of the induced plasticity mechanism;while the disappearance of the TWIP effect in the 316L stainless steel was also ***,the solid-solution strengthening in the 904L superaustenitic stainless steel maintained the tensile properties over a wide temper-ature range,surpassing the performance of 304L and 316L stainless *** this regard,the dependency of the total elongation on the de-formation temperature was less pronounced for the 904L alloy due to the absence of additional plasticity *** results re-vealed the importance of solid-solution strengthening and the associated high friction stress for superior mechanical behavior over a wide temperature range.

关键词： austenitic stainless steels mechanical behavior stacking fault energy metastability mechanical twinning

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Damage evolution and fragmentation behavior of pyramid cut blasting under uniaxial compression

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Journal of Mountain Science 2022年第5期19卷 1475-1486页

作者： CHEN Si-yu YANG Li-yun YANG Ai-yun HUANG Chen XIE Huan-zhen school of Mechanics and Civil Engineering China University of Mining and Technology-BeijingBeijing 100083China oulu mining school University of OuluOulu 90014Finland

Pyramid cut blasting is an essential form of inclined hole cut blasting,but the in-situ stress effect of pyramid cut blasting is rarely *** on the research background of pyramid cut blasting in a deep rock mass,the size,volume,and fragment size distribution of the blasting cavity before and after uniaxial compression were analysed by a model ***,the damage and effective stress of the pyramid cut blasting were analysed with LS-DYNA numerical *** results show that the damage and fragmentation of pyramid cut blasting are not only affected by blasting stress wave and blasting gas,but also affected by uniaxial *** the influence of uniaxial compression,the blasting stress wave and blasting gas are more likely to damage the rock mass parallel to the uniaxial compression direction near the connecting line of blasting hole,and make the volume of cavity larger and the fragment rate ***,uniaxial compression has a prominent influence during the middle and late stages of blasting.

关键词： Model test Pyramid cut blasting Blasting cavity sizes Uniaxial compression Fragment size

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Elucidating the anti-obesity phytochemicals in Chenpi and their molecular mechanisms

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Food Science and Human Wellness 2024年

作者： Jinhai Luo Weiqi Yan Zhi Chen Baojun Xu Guangdong Provincial Key Laboratory IRADS and Department of Life Sciences， BNU-HKBU United International College Centre for Cancer and Inflammation Research， school of Chinese Medicine， Hong Kong Baptist University Faculty of Biochemistry and Molecular Medicine， University of oulu

Obesity has become a significant global public health issue. Previous studies have found that the Chenpi has the anti-obesity activity. However， the anti-obesity phytochemicals and their mechanisms are still unclear. This study investigated the anti-obesity phytochemicals and molecular mechanisms involved in treating obesity by Chenpi through network pharmacology and molecular docking. Seventeen bioactive phytochemicals from Chenpi and its 475 related anti-obesity targets have been identified. The KEGG pathway analysis showed that the PI3K/Akt signaling pathway， MAPK signaling pathway， AMPK signaling pathway， and NF-kappa B signaling pathway are the main signaling pathways involved in the anti-obesity effect of Chenpi. According to molecular docking analysis， the phytochemicals of Chenpi can bind to central anti-obesity targets. Based on the ADMET analysis and network pharmacology results， tangeretin exhibited the lowest predicted toxicity and the highest potential for anti-obesity effects. In the in vitro lipid accumulation model， tangeretin effectively suppressed the FFA-induced lipid in HepG2 cells by upregulating the PI3K/Akt/GSK3β signaling pathway based on the result of q-PCR and Western Blotting. The outcomes of this research give insights for future research on the anti-obesity phytochemicals and molecular mechanisms derived from Chenpi， also providing the theoretical basis for developing anti-obesity functional foods based on Chenpi.

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