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Generalized polynomial chaos expansion by reanalysis using static condensation based on substructuring
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作者 D.LEE S.CHANG J.LEE 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第5期819-836,共18页
This paper presents a new computational method for forward uncertainty quantification(UQ)analyses on large-scale structural systems in the presence of arbitrary and dependent random inputs.The method consists of a gen... This paper presents a new computational method for forward uncertainty quantification(UQ)analyses on large-scale structural systems in the presence of arbitrary and dependent random inputs.The method consists of a generalized polynomial chaos expansion(GPCE)for statistical moment and reliability analyses associated with the stochastic output and a static reanalysis method to generate the input-output data set.In the reanalysis,we employ substructuring for a structure to isolate its local regions that vary due to random inputs.This allows for avoiding repeated computations of invariant substructures while generating the input-output data set.Combining substructuring with static condensation further improves the computational efficiency of the reanalysis without losing accuracy.Consequently,the GPCE with the static reanalysis method can achieve significant computational saving,thus mitigating the curse of dimensionality to some degree for UQ under high-dimensional inputs.The numerical results obtained from a simple structure indicate that the proposed method for UQ produces accurate solutions more efficiently than the GPCE using full finite element analyses(FEAs).We also demonstrate the efficiency and scalability of the proposed method by executing UQ for a large-scale wing-box structure under ten-dimensional(all-dependent)random inputs. 展开更多
关键词 forward uncertainty quantification(UQ) generalized polynomial chaos expansion(GPCE) static reanalysis method static condensation SUBSTRUCTURING
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CFD-PBM coupled modeling of the liquid-liquid dispersion characteristics and structure optimization for Kenics static mixer
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作者 Junhai Deng Shilin Lan +4 位作者 Juchang Wu Shenghua Du Weidong Liu Luchang Han Yefeng Zhou 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第6期173-188,共16页
Kenics static mixers(KSM)are extensively used in industrial mixing-reaction processes by virtue of high mixing efficiency,low power homogenization and easy continuous production.Resolving liquid droplet size and its d... Kenics static mixers(KSM)are extensively used in industrial mixing-reaction processes by virtue of high mixing efficiency,low power homogenization and easy continuous production.Resolving liquid droplet size and its distribution and thus revealing the dispersion characteristics are of great significance for structural optimization and process intensification in the KSM.In this work,a computational fluid dynamics-population balance model(CFD-PBM)coupled method is employed to systematically investigate the effects of operating conditions and structural parameters of KSM on droplet size and its distribution,to further reveal the liquid-liquid dispersion characteristics.Results indicate that higher Reynolds numbers or higher dispersed phase volume fractions increase energy dissipation,reducing Sauter mean diameter(SMD)of dispersed phase droplets and with a shift in droplet size distribution(DSD)towards smaller size.Smaller aspect ratios,greater blade twist and assembly angles amplify shear rate,leading to smaller droplet size and a narrower DSD in the smaller range.The degree of impact exerted by the aspect ratio is notably greater.Notably,mixing elements with different spin enhance shear and stretching efficiency.Compared to the same spin,SMD becomes 3.7-5.8 times smaller in the smaller size range with a significantly narrower distribution.Taking into account the pressure drop and efficiency in a comprehensive manner,optimized structural parameters for the mixing element encompass an aspect ratio of 1-1.5,a blade twist angle of 180°,an assembly angle of 90°,and interlaced assembly of adjacent elements with different spin.This work provides vital theoretical underpinning and future reference for enhancing KSM performance. 展开更多
关键词 CFD Population BALANCE LIQUID-LIQUID DISPERSION Kenics static MIXER
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Mechanical behavior and failure mechanisms of rock bolts subjected to static-dynamic loads
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作者 Hongpu Kang Guiyang Yuan +4 位作者 Linpo Si Fuqiang Gao Jinfu Lou Jinghe Yang Shuangyong Dong 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第3期281-288,共8页
This study explores the effects of dynamic and static loading on rock bolt performance a key factor in maintaining the structural safety of coal mine roadways susceptible to coal bursts.Employing a housemade load fram... This study explores the effects of dynamic and static loading on rock bolt performance a key factor in maintaining the structural safety of coal mine roadways susceptible to coal bursts.Employing a housemade load frame to simulate various failure scenarios,pretension-impact-pull tests on rock bolts were conducted to scrutinize their dynamic responses under varied static load conditions and their failure traits under combined loads.The experimental results denote that with increased impact energy,maximum and average impact loads on rock bolts escalate significantly under pretension,initiating plastic deformation beyond a certain threshold.Despite minor reductions in the yield load due to impactinduced damage,pretension aids in constraining post-impact deformation rate and fluctuation degree of rock bolts.Moreover,impact-induced plastic deformation causes internal microstructure dislocation,fortifying the stiffness of the rock bolt support system.The magnitude of this fortification is directly related to the plastic deformation induced by the impact.These findings provide crucial guidance for designing rock bolt support in coal mine roadway excavation,emphasizing the necessity to consider both static and dynamic loads for improved safety and efficiency. 展开更多
关键词 Rock bolt PRETENSION static and dynamic load IMPACT
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Static Stretching Combined with Conscious Slower Breathing May Increase Parasympathetic Activity and Reduce Stress in Adult Women
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作者 Mami Sakurai Yasushi Ikarashi +3 位作者 Masahiro Tabuchi Ailing Hu Takuji Yamaguchi Hiroyuki Kobayashi 《Health》 2024年第3期242-256,共15页
Background: Women are thought to be more susceptible to stress than men in a stressful society, and reducing stress is crucial for women to maintain their health. Static stretching (SST) is applied in various fields t... Background: Women are thought to be more susceptible to stress than men in a stressful society, and reducing stress is crucial for women to maintain their health. Static stretching (SST) is applied in various fields to not only increase muscle flexibility but also reduce stress. Additionally, conscious slower breathing (CSB) predominates parasympathetic activity, causing a relaxing effect. These results indicate that combining SST and CSB may be more useful in reducing stress. However, to the best of our knowledge, the effect of this combination remains unclear. Objective: This study aimed to elucidate the effects of the combination of SST and CSB on autonomic activity and stress in adult women. Methods: Eleven healthy Japanese adult female participants performed SST with nonconscious natural breathing for 20 min. The same participants performed SST in combination with CSB (2 s inspiratory and 4 s expiratory) for 20 min on another day. Salivary cortisol and chromogranin A levels were measured before and after stretching as stress markers of the hypothalamic-pituitary-adrenal axis and sympathetic nervous system. The coefficient of variation of the R-R interval (CVR-R) and high-frequency component (HF), which reflect parasympathetic nerve activity, and heart rate and low-frequency component (LF)/HF ratio, which reflect sympathetic nerve activity, were measured before, during, and after stretching. Results: SST decreased cortisol levels but with no significant changes in chromogranin A, heart rate, CVR-R, HF, or LF/HF ratio. The combination of SST and CSB increased CVR-R and HF levels in addition to decreasing cortisol levels but with no significant changes in chromogranin A, heart rate, or LF/HF levels. Conclusion: These results indicate that the combination of SST and CSB may increase parasympathetic activity and reduce stress. However, future randomized controlled trials with larger sample sizes should support this conclusion. 展开更多
关键词 static Stretching Conscious Slower Breathing Autonomic Activity Heart Rate Variability STRESS
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Acetaminophen overdose-induced acute liver injury can be alleviated by static magnetic field
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作者 Han-Xiao Chen Xin-Yu Wang +11 位作者 Biao Yu Chuan-Lin Feng Guo-Feng Cheng Lei Zhang Jun-Jun Wang Ying Wang Ruo-Wen Guo Xin-Miao Ji Wen-Jing Xie Wei-Li Chen Chao Song Xin Zhang 《Zoological Research》 SCIE CSCD 2024年第3期478-490,共13页
Acetaminophen(APAP),the most frequently used mild analgesic and antipyretic drug worldwide,is implicated in causing 46%of all acute liver failures in the USA and between 40%and 70%in Europe.The predominant pharmacolog... Acetaminophen(APAP),the most frequently used mild analgesic and antipyretic drug worldwide,is implicated in causing 46%of all acute liver failures in the USA and between 40%and 70%in Europe.The predominant pharmacological intervention approved for mitigating such overdose is the antioxidant N-acetylcysteine(NAC);however,its efficacy is limited in cases of advanced liver injury or when administered at a late stage.In the current study,we discovered that treatment with a moderate intensity static magnetic field(SMF)notably reduced the mortality rate in mice subjected to high-dose APAP from 40%to 0%,proving effective at both the initial liver injury stage and the subsequent recovery stage.During the early phase of liver injury,SMF markedly reduced APAPinduced oxidative stress,free radicals,and liver damage,resulting in a reduction in multiple oxidative stress markers and an increase in the antioxidant glutathione(GSH).During the later stage of liver recovery,application of vertically downward SMF increased DNA synthesis and hepatocyte proliferation.Moreover,the combination of NAC and SMF significantly mitigated liver damage induced by high-dose APAP and increased liver recovery,even 24 h post overdose,when the effectiveness of NAC alone substantially declines.Overall,this study provides a noninvasive non-pharmaceutical tool that offers dual benefits in the injury and repair stages following APAP overdose.Of note,this tool can work as an alternative to or in combination with NAC to prevent or minimize liver damage induced by APAP,and potentially other toxic overdoses. 展开更多
关键词 ACETAMINOPHEN Acute liver injury static magnetic fields Oxidative stress DNA synthesis
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Energy mechanism of bolt supporting effect to fissured rock under static and dynamic loads in deep coal mines
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作者 Deyuan Fan Xuesheng Liu +2 位作者 Yunliang Tan Xuebin Li Shenglong Yang 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第3期371-384,共14页
The stability control of fissured rock is difficult,especially under static and dynamic loads in deep coal mines.In this paper,the dynamic mechanical properties,strain rate evolution and energy dissipation of fissured... The stability control of fissured rock is difficult,especially under static and dynamic loads in deep coal mines.In this paper,the dynamic mechanical properties,strain rate evolution and energy dissipation of fissured and anchored rocks were respectively obtained by SHPB tests.It was found that bolt can provide supporting efficiency-improving effect for fissured rock against dynamic disturbance,and this effect increased quadratically with decrease in anchoring angles.Then,the energy dissipation mechanism of anchored rock was obtained by slipping model.Furthermore,bolt energy-absorbing mechanism by instantaneous tensile-shear deformation was expressed based on material mechanics,which was the larger the anchoring angle,the smaller the energy absorption,and the less the contribution to supporting efficiency improvement.On this basis,the functional relationship between energy dissipation of anchored rock and energy absorption of bolt was established.Taking the coal-gangue separation system of Longgu coal mine as an example,the optimal anchoring angle can be determined as 57.5°–67.5°.Field monitoring showed fissured rock with the optimal anchoring angle,can not only effectively control the deformation,but also fully exert the energy-absorbing and efficiency-improving effect of bolt itself.This study provides guidance to the stability control and supporting design for deep engineering under the same or similar conditions. 展开更多
关键词 static and dynamic loads Anchored rock Energy absorption Anchoring angle Engineering verification
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Mechanical behavior of 2G NPR bolt anchored rock samples under static disturbance loading
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作者 WANG Jiong JIANG Jian +4 位作者 WANG Siyu CHANG Yiwen LIU Peng HE Manchao CHENG Shuang 《Journal of Mountain Science》 SCIE CSCD 2024年第7期2494-2516,共23页
The deep mining of coal resources is accompanied by severe environmental challenges and various potential engineering hazards.The implementation of NPR(negative Poisson's ratio)bolts are capable of controlling lar... The deep mining of coal resources is accompanied by severe environmental challenges and various potential engineering hazards.The implementation of NPR(negative Poisson's ratio)bolts are capable of controlling large deformations in the surrounding rock effectively.This paper focuses on studying the mechanical properties of the NPR bolt under static disturbance load.The deep nonlinear mechanical experimental system was used to study the mechanical behavior of rock samples with different anchored types(unanchored/PR anchored/2G NPR anchored)under static disturbance load.The whole process of rock samples was taken by high-speed camera to obtain the real-time failure characteristics under static disturbance load.At the same time,the acoustic emission signal was collected to obtain the key characteristic parameters of acoustic emission such as acoustic emission count,energy,and frequency.The deformation at the failure of the samples was calculated and analyzed by digital speckle software.The findings indicate that the failure mode of rock is influenced by different types of anchoring.The peak failure strength of 2G NPR bolt anchored rock samples exhibits an increase of 6.5%when compared to the unanchored rock samples.The cumulative count and cumulative energy of acoustic emission exhibit a decrease of 62.16%and 62.90%,respectively.The maximum deformation of bearing capacity exhibits an increase of 59.27%,while the failure time demonstrates a delay of 42.86%.The peak failure strength of the 2G NPR bolt anchored ones under static disturbance load exhibits an increase of 5.94%when compared to the rock anchored by PR(Poisson's ratio)bolt.The cumulative count and cumulative energy of acoustic emission exhibit a decrease of 47.16%and 43.86%,respectively.The maximum deformation of the bearing capacity exhibits an increase of 50.43%,and the failure time demonstrates a delay of 32%.After anchoring by 2G NPR bolt,anchoring support effectively reduces the risk of damage caused by static disturbance load.These results demonstrate that the support effect of 2G NPR bolt materials surpasses that of PR bolt. 展开更多
关键词 Anchored rock samples static disturbance load Acoustic emission characteristics Digital speckle Negative Poisson's ratio
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Static and Thermal Analysis of Aluminium (413,390,384 and 332) Piston Using Finite Element Method
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作者 Offei David Inusah Jacob Kwaku Nkrumah Vincent Akolbire Atindana 《Modeling and Numerical Simulation of Material Science》 2024年第1期1-38,共38页
The main objective of this research was to examine the suitability of aluminium alloy to design a piston of an internal combustion engine for improvement in weight and cost reduction. The piston was modelled using Aut... The main objective of this research was to examine the suitability of aluminium alloy to design a piston of an internal combustion engine for improvement in weight and cost reduction. The piston was modelled using Autodesk Inventor 2017 software. The modelled piston was then imported into Ansys for further analysis. Static structural and thermal analysis were carried out on the pistons of the four different materials namely: Al 413 alloy, Al 384 alloy, Al 390 alloy and Al332 alloy to determine the total deformation, equivalent Von Mises stress, maximum shear stress, and the safety factor. The results of the study revealed that, aluminium 332 alloy piston deformed less compared to the deformations of aluminium 390 alloy piston, aluminium 384 alloy piston and aluminium 413 alloy piston. The induced Von Mises stresses in the pistons of the four different materials were found to be far lower than the yield strengths of all the materials. Hence, all the selected materials including the implementing material have equal properties to withstand the maximum gas load. All the selected materials were observed to have high thermal conductivity enough to be able to withstand the operating temperature in the engine cylinders. 展开更多
关键词 Von Mise stress Total deformation Aluminium alloy Thermal analysis. PISTON static structural Heat fux
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Novel Static Security and Stability Control of Power Systems Based on Artificial Emotional Lazy Q-Learning
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作者 Tao Bao Xiyuan Ma +3 位作者 Zhuohuan Li Duotong Yang Pengyu Wang Changcheng Zhou 《Energy Engineering》 EI 2024年第6期1713-1737,共25页
The stability problem of power grids has become increasingly serious in recent years as the size of novel power systems increases.In order to improve and ensure the stable operation of the novel power system,this stud... The stability problem of power grids has become increasingly serious in recent years as the size of novel power systems increases.In order to improve and ensure the stable operation of the novel power system,this study proposes an artificial emotional lazy Q-learning method,which combines artificial emotion,lazy learning,and reinforcement learning for static security and stability analysis of power systems.Moreover,this study compares the analysis results of the proposed method with those of the small disturbance method for a stand-alone power system and verifies that the proposed lazy Q-learning method is able to effectively screen useful data for learning,and improve the static security stability of the new type of power system more effectively than the traditional proportional-integral-differential control and Q-learning methods. 展开更多
关键词 Artificial sentiment static secure stable analysis Q-LEARNING lazy learning data filtering
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Influence of static cartoons combined with dynamic virtual environments on preoperative anxiety of preschool-aged children undergoing surgery
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作者 Ya-Lin Zhang Qi-Ying Zhou +3 位作者 Peng Zhang Lin-Feng Huang Li Jin Zhi-Guo Zhou 《World Journal of Clinical Cases》 SCIE 2024年第22期4947-4955,共9页
BACKGROUND Preschoolers become anxious when they are about to undergo anesthesia and surgery,warranting the development of more appropriate and effective interventions.AIM To explore the effect of static cartoons comb... BACKGROUND Preschoolers become anxious when they are about to undergo anesthesia and surgery,warranting the development of more appropriate and effective interventions.AIM To explore the effect of static cartoons combined with dynamic virtual environments on preoperative anxiety and anesthesia induction compliance in preschool-aged children undergoing surgery.METHODS One hundred and sixteen preschool-aged children were selected and assigned to the drug(n=37),intervention(n=40),and control(n=39)groups.All the children received routine preoperative checkups and nursing before being transferred to the preoperative preparation room on the day of the operation.The drug group received 0.5 mg/kg midazolam and the intervention group treatment consisting of static cartoons combined with dynamic virtual environments.The control group received no intervention.The modified Yale Preoperative Anxiety Scale was used to evaluate the children’s anxiety level on the day before surgery(T0),before leaving the preoperative preparation room(T1),when entering the operating room(T2),and at anesthesia induction(T3).Compliance during anesthesia induction(T3)was evaluated using the Induction Compliance Checklist(ICC).Changes in mean arterial pressure(MAP),heart rate(HR),and respiratory rate(RR)were also recorded at each time point.RESULTS The anxiety scores of the three groups increased variously at T1 and T2.At T3,both the drug and intervention groups had similar anxiety scores,both of which were lower than those in the control group.At T1 and T2,MAP,HR,and RR of the three groups increased.The drug and control groups had significantly higher MAP and RR than the intervention group at T2.At T3,the MAP,HR,and RR of the drug group decreased and were significantly lower than those in the control group but were comparable to those in the intervention group.Both the drug and intervention groups had similar ICC scores and duration of anesthesia induction(T3),both of which were higher than those of the control group.CONCLUSION Combining static cartoons with dynamic virtual environments as effective as medication,specifically midazolam,in reducing preoperative anxiety and fear in preschool-aged children.This approach also improve their compliance during anesthesia induction and helped maintain their stable vital signs. 展开更多
关键词 PRESCHOOL Children static cartoons combined with dynamic virtual environments Preoperative anxiety COMPLIANCE Anesthesia induction
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Study of damage behavior and repair effectiveness of patch repaired carbon fiber laminate under quasi-static indentation loading
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作者 Alok Kumar Chinmaya Kumar Sahoo A.Arockiarajan 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第4期29-41,共13页
Damage caused due to low-velocity impacts in composites leads to substantial deterioration in their residual strength and eventually provokes structural failure.This work presents an experimental investigation on the ... Damage caused due to low-velocity impacts in composites leads to substantial deterioration in their residual strength and eventually provokes structural failure.This work presents an experimental investigation on the effects of different patch and parent laminate stacking sequences on the enhancement of impact strength of Carbon Fiber Reinforced Polymers(CFRP)composites by utilising the adhesively bonded external patch repair technique.Damage evolution study is also performed with the aid of Acoustic Emission(AE).Two different quasi-isotropic configurations were selected for the parent laminate,viz.,[45°/45°/0°/0°]s and[45°/0°/45°/0°]s.Quasi Static Indentation(QSI)test was performed on both the pristine laminates,and damage areas were detected by using the C-scan inspection technique.Damaged laminates were repaired by using a single-sided patch of two different configurations,viz.,[45°/45°/45°/45°]and[45°/0°/0°/45°],and employing a circular plug to fill the damaged hole.Four different combinations of repaired laminates with two configurations of each parent and patch laminate were produced,which were further subjected to the QSI test.The results reveal the effectiveness of the repair method,as all the repaired laminates show higher impact resistance compared to the respective pristine laminates.Patches of[45°/0°/0°/45°]configuration when repaired by taking[45°/45°/0°/0°]s and[45°/0°/45°/0°]s as parents exhibited 68%and 73%higher peak loads,respectively,than the respective pristine laminates.Furthermore,parent and patch of configuration[45°/0°/45°/0°]s and[45°/0°/0°/45°],respectively,attain the highest peak load,whereas[45°/45°/0°/0°]s and[45°/45°/45°/45°]combinations possess the most gradual decrease in the load. 展开更多
关键词 Carbon fiber reinforced polymers(CFRP) Quasi-isotropic laminate Quasi static indentation(QSI) Acoustic emission(AE) Composite repair
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Analysis of the Application of Static Load Test in Bridge Bearing Capacity Testing
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作者 Wei Fu Bo Liu 《Journal of Architectural Research and Development》 2024年第3期36-41,共6页
This article uses real engineering projects as examples to analyze how static load test technology is applied in testing the bridge-bearing capacity.The analysis covers aspects such as testing section layout,test load... This article uses real engineering projects as examples to analyze how static load test technology is applied in testing the bridge-bearing capacity.The analysis covers aspects such as testing section layout,test load and efficiency coefficient,loading plan,evaluation optimization,test result modification,and result evaluation.The aim is to support the accurate detection and evaluation of bridge-bearing capacity. 展开更多
关键词 Bridge engineering Bearing capacity static load test Loading plan Test evaluation
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Quantitative investigation of multi-fracture morphology during TPDF through true tri-axial fracturing experiments and CT scanning 被引量:5
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作者 Ming-Hui Li Fu-Jian Zhou +3 位作者 Jin-Jun Liu Li-Shan Yuan Guo-Peng Huang Bo Wang 《Petroleum Science》 SCIE CAS CSCD 2022年第4期1700-1717,共18页
Due to the reservoir heterogeneity and the stress shadow effect, multiple hydraulic fractures within one fracturing segment cannot be initiated simultaneously and propagate evenly, which will cause a low effectiveness... Due to the reservoir heterogeneity and the stress shadow effect, multiple hydraulic fractures within one fracturing segment cannot be initiated simultaneously and propagate evenly, which will cause a low effectiveness of reservoir stimulation. Temporary plugging and diverting fracturing(TPDF) is considered to be a potential uniform-stimulation method for creating multiple fractures simultaneously in the oilfield. However, the multi-fracture propagation morphology during TPDF is not clear now. The purpose of this study is to quantitatively investigate the multi-fracture propagation morphology during TPDF through true tri-axial fracturing experiments and CT scanning. Critical parameters such as fracture spacing, number of perforation clusters, the viscosity of fracturing fluid, and the in-situ stress have been investigated. The fracture geometry before and after diversion have been quantitively analyzed based on the two-dimensional CT slices and three-dimensional reconstruction method. The main conclusions are as follows:(1) When injecting the high viscosity fluid or perforating at the location with low in-situ stress, multiple hydraulic fractures would simultaneously propagate. Otherwise, only one hydraulic fracture was created during the initial fracturing stage(IFS) for most tests.(2) The perforation cluster effectiveness(PCE) has increased from 26.62% during the IFS to 88.86% after using diverters.(3) The diverted fracture volume has no apparent correlation with the pressure peak and peak frequency during the diversion fracturing stage(DFS) but is positively correlated with water-work.(4) Four types of plugging behavior in shale could be controlled by adjusting the diverter recipe and diverter injection time, and the plugging behavior includes plugging the natural fracture in the wellbore, plugging the previous hydraulic fractures, plugging the fracture tip and plugging the bedding. 展开更多
关键词 Hydraulic fracturing Temporary plugging and diverting fracturing(TPDF) Multiple fracture tri-axial experiment CT scanning
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Hydrologically induced orientation variations of a tri-axial Earth's principal axes based on satellite-gravimetric and hydrological models 被引量:1
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作者 Shen Wenbin Sun Rong 《Geodesy and Geodynamics》 2013年第2期30-39,共10页
The Earth is a tri-axial body, with unequal principal inertia moments, A, B and C. The corresponding principal axes a, b and c are determined by the mass distribution of the Earth, and their orientations vary with the... The Earth is a tri-axial body, with unequal principal inertia moments, A, B and C. The corresponding principal axes a, b and c are determined by the mass distribution of the Earth, and their orientations vary with the mass redistribution. In this study, the hydrologically induced variations are estimated on the basis of satellite gravimetric data, including those from satellite laser ranging (SLR) and gravity recovery and climate experiment (GRACE), and hydrological models from global land data assimilation system (GLDAS). The longitude variations of a and b are mainly related to the variations of the spherical harmonic coefficients C 22 and S 22, which have been estimated to be consisting annual variations of about 1.6 arc seconds and 1.8 arc seconds, respectively, from gravity data. This result is confirmed by land surface water storage provided by the GLDAS model. If the atmospheric and oceanic signals are removed from the spherical harmonic coefficients C 21 and S 21, the agreement of the orientation series for c becomes poor, possibly due to the inaccurate background models used in pre-processing of the satellite gravimetric data. Determination of the orientation variations may provide a better understanding of various phenomena in the study of the rotation of a tri-axial Earth. 展开更多
关键词 SLR GRACE GLDAS tri-axial axes orientation variation
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Determination of Direction of Arrival of Seismic Wave by a Single Tri-axial Fiber Optic Geophone 被引量:1
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作者 CHANG Tianying CUI Hongliang 《Defence Technology(防务技术)》 SCIE EI CAS 2013年第1期1-10,共10页
A fiber Bragg grating (FBG) geophone and a surface seismic wave-based algorithm for detecting the direction of arrival (DOA) are described. The operational principle of FBG geophone is introduced and illustrated with ... A fiber Bragg grating (FBG) geophone and a surface seismic wave-based algorithm for detecting the direction of arrival (DOA) are described. The operational principle of FBG geophone is introduced and illustrated with systematic experimental data, demonstrating an improved FBG geophone with many advantages over the conventional geophones. An innovative, robust, and simple algorithm is developed for obtaining the bearing information on the seismic events, such as people walking, or vehicles moving. Such DOA estimate is based on the interactions and projections of surface-propagating seismic waves generated by the moving personnel or vehicles with a single tri-axial seismic sensor based on FBGs. Of particular interest is the case when the distance between the source of the seismic wave and the detector is less than or comparable to one wavelength (less than 100 m), corresponding to near-field detection, where an effective method of DOA finding lacks. 展开更多
关键词 information processing fiber optic geophone direction of arrival (DOA) tri-axial seismic wave sensing surface seismic wave
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Effects of gradient high-field static magnetic fields on diabetic mice 被引量:3
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作者 Biao Yu Chao Song +11 位作者 Chuan-Lin Feng Jing Zhang Ying Wang Yi-Ming Zhu Lei Zhang Xin-Miao Ji Xiao-Fei Tian Guo-Feng Cheng Wei-Li Chen Vitalii Zablotskii Hua Wang Xin Zhang 《Zoological Research》 SCIE CAS CSCD 2023年第2期249-258,共10页
Although 9.4 T magnetic resonance imaging(MRI) has been tested in healthy volunteers,its safety in diabetic patients is unclear.Furthermore,the effects of high static magnetic fields(SMFs),especially gradient vs.unifo... Although 9.4 T magnetic resonance imaging(MRI) has been tested in healthy volunteers,its safety in diabetic patients is unclear.Furthermore,the effects of high static magnetic fields(SMFs),especially gradient vs.uniform fields,have not been investigated in diabetics.Here,we investigated the consequences of exposure to 1.0-9.4 T high SMFs of different gradients(>10 T/m vs.0-10 T/m)on type 1 diabetic(T1D) and type 2 diabetic(T2D) mice.We found that 14 h of prolonged treatment of gradient(as high as 55.5 T/m) high SMFs(1.0-8.6 T) had negative effects on T1D and T2D mice,including spleen,hepatic,and renal tissue impairment and elevated glycosylated serum protein,blood glucose,inflammation,and anxiety,while 9.4 T quasi-uniform SMFs at 0-10 T/m did not induce the same effects.In regular T1D mice(blood glucose>16.7 mmol/L),the>10 T/m gradient high SMFs increased malondialdehyde(P<0.01) and decreased superoxide dismutase(P<0.05).However,in the severe T1D mice(blood glucose≥30.0 mmol/L),the>10 T/m gradient high SMFs significantly increased tissue damage and reduced survival rate.In vitro cellular studies showed that gradient high SMFs increased cellular reactive oxygen species and apoptosis and reduced MS-1 cell number and proliferation.Therefore,this study showed that prolonged exposure to high-field(1.0-8.6 T)>10 T/m gradient SMFs(35-1 380 times higher than that of current clinical MRI)can have negative effects on diabetic mice,especially mice with severe T1D,whereas 9.4 T high SMFs at 0-10T/m did not produce the same effects,providing important information for the future development and clinical application of SMFs,especially high-field MRI. 展开更多
关键词 Type 2 diabetes Type 1 diabetes Magnetic resonance imaging(MRI) Gradient static magnetic field Quasi-uniform static magnetic field
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Improved Prediction of Slope Stability under Static and Dynamic Conditions Using Tree-BasedModels 被引量:2
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作者 Feezan Ahmad Xiaowei Tang +2 位作者 Jilei Hu Mahmood Ahmad Behrouz Gordan 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第10期455-487,共33页
Slope stability prediction plays a significant role in landslide disaster prevention and mitigation.This paper’s reduced error pruning(REP)tree and random tree(RT)models are developed for slope stability evaluation a... Slope stability prediction plays a significant role in landslide disaster prevention and mitigation.This paper’s reduced error pruning(REP)tree and random tree(RT)models are developed for slope stability evaluation and meeting the high precision and rapidity requirements in slope engineering.The data set of this study includes five parameters,namely slope height,slope angle,cohesion,internal friction angle,and peak ground acceleration.The available data is split into two categories:training(75%)and test(25%)sets.The output of the RT and REP tree models is evaluated using performance measures including accuracy(Acc),Matthews correlation coefficient(Mcc),precision(Prec),recall(Rec),and F-score.The applications of the aforementionedmethods for predicting slope stability are compared to one another and recently established soft computing models in the literature.The analysis of the Acc together with Mcc,and F-score for the slope stability in the test set demonstrates that the RT achieved a better prediction performance with(Acc=97.1429%,Mcc=0.935,F-score for stable class=0.979 and for unstable case F-score=0.935)succeeded by the REP tree model with(Acc=95.4286%,Mcc=0.896,F-score stable class=0.967 and for unstable class F-score=0.923)for the slope stability dataset The analysis of performance measures for the slope stability dataset reveals that the RT model attains comparatively better and reliable results and thus should be encouraged in further research. 展开更多
关键词 Slope stability seismic excitation static condition random tree reduced error pruning tree
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Effect of a static pedestrian as an exit obstacle on evacuation 被引量:1
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作者 胡杨慧 毕钰帛 +3 位作者 张俊 练丽萍 宋卫国 高伟 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第1期615-625,共11页
Building exit as a bottleneck structure is the last and the most congested stage in building evacuation.It is well known that obstacles at the exit affect the evacuation process,but few researchers pay attention to th... Building exit as a bottleneck structure is the last and the most congested stage in building evacuation.It is well known that obstacles at the exit affect the evacuation process,but few researchers pay attention to the effect of stationary pedestrians(the elderly with slow speed,the injured,and the static evacuation guide)as obstacles at the exit on the evacuation process.This paper explores the influence of the presence of a stationary pedestrian as an obstacle at the exit on the evacuation from experiments and simulations.We use a software,Pathfinder,based on the agent-based model to study the effect of ratios of exit width(D)to distance(d)between the static pedestrian and the exit,the asymmetric structure by shifting the static pedestrian upward,and types of obstacles on evacuation.Results show that the evacuation time of scenes with a static pedestrian is longer than that of scenes with an obstacle due to the unexpected hindering effect of the static pedestrian.Different ratios of D/d have different effects on evacuation efficiency.Among the five D/d ratios in this paper,the evacuation efficiency is the largest when d is equal to 0.75D,and the existence of the static pedestrian has a positive impact on evacuation in this condition.The influence of the asymmetric structure of the static pedestrian on evacuation efficiency is affected by D/d.This study can provide a theoretical basis for crowd management and evacuation plan near the exit of complex buildings and facilities. 展开更多
关键词 EVACUATION exit obstacle static pedestrian pathfinder simulation
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Origin of extension twinning-mediated static recrystallization and unique parallel alignment of(0001) poles to transverse direction in Mg-3Al-0.4Mn(mass%) alloy sheet
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作者 T.Nakata C.Xu +1 位作者 L.Geng S.Kamado 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2023年第9期3200-3213,共14页
The origin of unique parallel alignment of(0001) poles to transverse direction(TD) was investigated using Mg-3Al-0.4Mn(mass%)alloy sheets rolled with different process conditions. When rolling was performed with inter... The origin of unique parallel alignment of(0001) poles to transverse direction(TD) was investigated using Mg-3Al-0.4Mn(mass%)alloy sheets rolled with different process conditions. When rolling was performed with intermediate reheating, the alloy showed a sluggish static recrystallization(SRX) behavior during post-annealing, facilitating the nucleation and growth of statically recrystallized grains from extension twins. This resulted in the apparent texture component with the parallel alignment of the(0001) poles to the TD, and the sheet exhibited good ductility for both the rolling direction(RD) and TD. In contrast, continuous rolling without intermediate reheating led to the formation of severely deformed regions near double twins. SRX was promoted at such regions, forming a typical basal textural feature with weak RD-split of the(0001) poles. Although extension twins were formed after the continuous rolling, SRX was facilitated at the severely deformed regions with double twins, and the formation of the unique alignment of the(0001) poles to the TD was suppressed. The RD-split texture led to the large elongation to failure along the RD, while it along the TD decreased owing to the narrow distribution of the(0001)poles toward the TD, resulting in the in-plane anisotropy in ductility. 展开更多
关键词 Magnesium Rolling TWINNING static recrystallization Texture
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Technical Analysis of Highway Bridge Static Load Test 被引量:1
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作者 Ke Tu Yingying Ye +2 位作者 Daqing Wu Yunyong Zhou Wenming Deng 《Journal of Architectural Research and Development》 2023年第3期58-63,共6页
Highway bridges are an important part of the transportation industry and can promote social economic construction and development.In actual operation,highway bridges are often damaged due to overload and natural facto... Highway bridges are an important part of the transportation industry and can promote social economic construction and development.In actual operation,highway bridges are often damaged due to overload and natural factors,which tend to affect the safety and shorten the service life of these bridges.Assessing the overall state and performance of highway bridges is therefore a key element.Static load test,which is a type of sustainable detection experiment,has many advantages,including low cost,high efficiency,and high accuracy.In this paper,the bridge structure is analyzed through the application of theoretical calculations and relevant comparisons,so as to judge the operating state of the bridge. 展开更多
关键词 Highway bridge static load test Detection technology
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