The authors investigate the failure modes surrounding over-stressed tunnels in rock.Three lines of investigation are employed:failure in over-stressed three-dimensional(3D) models of tunnels bored under 3D stress,fail...The authors investigate the failure modes surrounding over-stressed tunnels in rock.Three lines of investigation are employed:failure in over-stressed three-dimensional(3D) models of tunnels bored under 3D stress,failure modes in two-dimensional(2D) numerical simulations of 1000 m and 2000 m deep tunnels using FRACOD,both in intact rock and in rock masses with one or two joint sets,and finally,observations in TBM(tunnel boring machine) tunnels in hard and medium hard massive rocks.The reason for 'stress-induced' failure to initiate,when the assumed maximum tangential stress is approximately(0.4-0.5)σ_c(UCS,uniaxial compressive strength) in massive rock,is now known to be due to exceedance of a critical extensional strain which is generated by a Poisson's ratio effect.However,because similar 'stress/strength' failure limits are found in mining,nuclear waste research excavations,and deep road tunnels in Norway,one is easily misled into thinking of compressive stress induced failure.Because of this,the empirical SRF(stress reduction factor in the Q-system) is set to accelerate as the estimated ratio σ_(θmax)/σ_c >> 0.4.In mining,similar 'stress/strength' ratios are used to suggest depth of break-out.The reality behind the fracture initiation stress/strength ratio of '0.4' is actually because of combinations of familiar tensile and compressive strength ratios(such as 10) with Poisson's ratio(say0.25).We exceed the extensional strain limits and start to see acoustic emission(AE) when tangential stress σθ ≈ 0.4σc,due to simple arithmetic.The combination of 2D theoretical FRACOD models and actual tunnelling suggests frequent initiation of failure by 'stable' extensional strain fracturing,but propagation in 'unstable' and therefore dynamic shearing.In the case of very deep tunnels(and 3D physical simulations),compressive stresses may be too high for extensional strain fracturing,and shearing will dominate,both ahead of the face and following the face.When shallower,the concept of 'extensional strain initiation but propagation' in shear is suggested.The various failure modes are richly illustrated,and the inability of conventional continuum modelling is emphasized,unless cohesion weakening and friction mobilization at different strain levels are used to reach a pseudo state of yield,but still considering a continuum.展开更多
Research on the mechanical–electrical properties is crucial for designing and preparing high-temperature superconducting(HTS)cables.Various winding core structures can influence the mechanical–electrical behavior of...Research on the mechanical–electrical properties is crucial for designing and preparing high-temperature superconducting(HTS)cables.Various winding core structures can influence the mechanical–electrical behavior of cables,but the impact of alterations in the winding core structure on the mechanical–electrical behavior of superconducting cables remains unclear.This paper presents a 3D finite element model to predict the performance of three cables with different core structures when subjected to transverse compression and axial tension.The three cables analyzed are CORC(conductor-on-round-core),CORT(conductor-on-round-tube),and HFRC(conductor-on-spiral-tube).A parametric analysis is carried out by varying the core diameter and inner-to-outer diameter ratio.Results indicate that the CORT cable demonstrates better performance in transverse compression compared to the CORC cable,aligning with experimental data.Among the three cables,the HFRC cables exhibit the weakest resistance to transverse deformation.However,the HFRC cable demonstrates superior tensile deformation resistance compared to the CORT cable,provided that the transverse compression properties are maintained.Finite element results also show that the optimum inner-to-outer diameter ratios for achieving the best transverse compression performance are approximately 0.8 for CORT cables and 0.6 for HFRC cables.Meanwhile,the study explores the effect of structural changes in HTS cable winding cores on their electromagnetic properties.It recommends utilizing small tape gaps,lower frequencies,and spiral core construction to minimize eddy losses.The findings presented in this paper offer valuable insights for the commercialization and practical manufacturing of HTS cables.展开更多
A deep-sea mining riser is a crucial component of the system used to lift seafloor mineral resources to the vessel.It is prone to damage and failure because of harsh environmental conditions and internal fluid erosion...A deep-sea mining riser is a crucial component of the system used to lift seafloor mineral resources to the vessel.It is prone to damage and failure because of harsh environmental conditions and internal fluid erosion.Furthermore,damage can impact the response characteristics of the riser,but varying environmental loadings easily mask it.Thus,distin-guishing between riser damage and environmental effects poses a considerable challenge.To address this issue,a cantilevered model is created for a deep-sea mining riser via the concentrated mass method,and a time-domain analytical strategy is developed.The vortex-induced vibration(VIV)response characteristics of the riser are initially examined,considering various damage conditions and flow velocities.The study results revealed four primary observations:(a)effective tension can serve as a reliable indicator for identifying damage at lower velocities;(b)there are noticeable differences in displacement between the healthy and damaged risers in the in-line direction rather than the cross-flow direction;(c)frequency characteristics can more effectively distinguish the damage conditions at high flow velocities,with the mean square frequency and frequency variance being more effective than the centroid frequency and root variance frequency;(d)displacement differences are more sensitive to damage occurring near the top and bottom of the riser,while both velocity variations and structural damage can influence displacements,especially in regions between modal nodes.The vibrational behavior and damage indicators are clarified for structural health monitoring of deep-sea mining risers during lifting operations.展开更多
Understanding the mesoscopic tensile fracture damage of rock is the basis of evaluating the deterioration process of mechanical properties of heat-damaged rock. For this, tensile tests of rocks under high-temperature ...Understanding the mesoscopic tensile fracture damage of rock is the basis of evaluating the deterioration process of mechanical properties of heat-damaged rock. For this, tensile tests of rocks under high-temperature treatment were conducted with a ϕ75 mm split Hopkinson tension bar (SHTB) to investigate the mesoscopic fracture and damage properties of rock. An improved scanning electron microscopy (SEM) experimental method was used to analyze the tensile fracture surfaces of rock samples. Qualitative and quantitative analyses were performed to assess evolution of mesoscopic damage of heat-damaged rock under tensile loading. A constitutive model describing the mesoscopic fractal damage under thermo-mechanical coupling was established. The results showed that the high temperatures significantly reduced the tensile strength and fracture surface roughness of the red sandstone. The three-dimensional (3D) reconstruction of the fracture surface of the samples that experienced tensile failure at 900 °C showed a flat surface. The standard deviation of elevation and slope angle of specimen fracture surface first increased and then decreased with increasing temperature. The threshold for brittle fracture of the heat-damaged red sandstone specimens was 600 °C. Beyond this threshold temperature, local ductile fracture occurred, resulting in plastic deformation of the fracture surface during tensile fracturing. With increase of temperature, the internal meso-structure of samples was strengthened slightly at first and then deteriorated gradually, which was consistent with the change of macroscopic mechanical properties of red sandstone. The mesoscopic characteristics, such as the number, mean side length, maximum area, porosity, and fractal dimension of crack, exhibited an initial decline, followed by a gradual increase. The development of microcracks in samples had significant influence on mesoscopic fractal dimension. The mesoscopic fractal characteristics were used to establish a mesoscopic fractal damage constitutive model for red sandstone, and the agreement between the theoretical and experimental results validated the proposed model.展开更多
Mooring cable tension is a crucial parameter for evaluating the safety and reliability of a floating platform mooring system.The real-time mooring tension in an actual marine environment has always been essential data...Mooring cable tension is a crucial parameter for evaluating the safety and reliability of a floating platform mooring system.The real-time mooring tension in an actual marine environment has always been essential data that mooring system designers aim to acquire.To address the need for long-term continuous monitoring of mooring tension in deep-sea marine environments,this paper presents a mooring cable tension monitoring method based on the principle of direct mechanical measurement.The developed tension monitoring sensors were installed and applied in the mooring system of the"Yongle"scientific experimental platform.Over the course of one year,a substantial amount of in-situ tension monitoring data was obtained.Under wave heights of up to 1.24 m,the mooring tension on the floating platform reached 16.5 tons.Through frequency domain and time domain analysis,the spectral characteristics of mooring tension,including waveinduced force,slow drift force,and mooring cable elastic restoring force,were determined.The mooring cable elastic restoring force frequency was approximately half of that of the wave signal.Due to the characteristics of the hinge connection structure of the dual module floating platform,under some specific working conditions the wave-induced force was the maximum of the three different frequency forces,and restoring force was the smallest.展开更多
The deformation and fracture of a third-generation single crystal superalloy during in-situ tension at room temperature were investigated at multiple scales by scanning electron microscope,electron back-scattered diff...The deformation and fracture of a third-generation single crystal superalloy during in-situ tension at room temperature were investigated at multiple scales by scanning electron microscope,electron back-scattered diffractometer,and transmission electron microscope to reveal the deformation and fracture mechanism during tension.The proportion of low angle boundaries(LABs)with angles from 2.5°to 5.5°increases during tension.The change in LABs is particularly pronounced after elongation over 7%.The initiation of microcracks is caused by{111}<110>slip systems.After initiation,the crack size along the stress direction increases whereas the size extension along slip systems is suppressed.The fracture mode of the alloy is quasi-cleavage fracture and the slip lines near the fracture are implicit at room temperature.展开更多
Sodium cocoyl glycinate(SCG),an environmentally friendly anionic amino acid surfactant,is widely used in daily chemical products as an upgraded alternative to traditional surfactants.In this study,crude Camellia oleif...Sodium cocoyl glycinate(SCG),an environmentally friendly anionic amino acid surfactant,is widely used in daily chemical products as an upgraded alternative to traditional surfactants.In this study,crude Camellia oleifera saponin(COS)was purified using AB-8 macroporous adsorption resin,and its composition and structure were analyzed.The effects of different mole fractions of COS(αCOS)on surface tension(γ),oil-water interfacial tension(IFT),emulsification,and foam properties of COS-SCG binary mixed systems were investigated in mixtures of SCG with purified COS.The stability ofγand foamability under diverse environmental conditions were also discussed.The results indicated that the COS-SCG system exhibited remarkable surface-active synergism.The minimum critical micelle concentration(cmc)of the mixed system was lower than that of SCG,and adding a small mole fraction of COS(1%-2%)induced a synergistic reduction ofγ.Specifically,the cmc andγwere 2.50×10-4 mol/L and 23.1 mN/m forαCOS=1%,respectively.The system exhibited exceptional IFT reduction capacity,achieving a minimum value of 1.42 mN/m atαCOS=10%.The mixed system reached a foaming volume(atαCOS=50%)and foam stability(atαCOS=75%)were 51.0 mL and 97.37%,respectively.Microscopic analysis further confirmed these outstanding foam properties.Moreover,the COS-SCG system displayed reducedγwith enhanced foaming volume under elevated temperatures(35-75℃)and salinity(0-20 g/L).However,acidic conditions and hard water compromised bothγstability and foamability.展开更多
OBJECTIVE To investigate the intervention effects of tissue-bone homeostasis manipulation(TBHM)on peripatellar biomechanical parameters and knee joint function in knee osteoarthritis(KOA)patients.METHODS Sixty patient...OBJECTIVE To investigate the intervention effects of tissue-bone homeostasis manipulation(TBHM)on peripatellar biomechanical parameters and knee joint function in knee osteoarthritis(KOA)patients.METHODS Sixty patients with KOA(Kellgren-Lawrence gradeⅡ-Ⅲ)were recruited from the Acupuncture-Moxibustion Rehabilitation Department,Anhui University of Chinese Medicine between October 2024 and May 2025.Participants were randomized into a TBHM group(n=30)or a transcutaneous electrical neuromuscular stimulation(TENS)group(n=30).Using two-way repeated measures ANOVA,biomechanical indicators,including rectus femoris tension,vastus medialis tension,vastus lateralis tension,patellar ligament tension,lateral patellar displacement(LPD),medial patellar displacement(MPD),normalized patellar mobility(LPD/patellar width[PW],MPD/PW),knee flexion range of motion,and functional indicators,including KOOS subscales,time up and go test(TUGT),were compared between groups at baseline and after 6 weeks of intervention.RESULTS After intervention,all biomechanical and knee joint function indicators in the TBHM group were significantly improved(P<0.05,P<0.01),while only the vastus medialis tension,TUGT and KOOS Pain,ADL and QoL scores in the control group were significantly improved(P<0.01).The improvement amplitudes of biomechanical indicators in the TBHM group,including rectus femoris tension,vastus lateralis tension,patellar ligament tension,MPD/PW,LPD/PW and knee flexion range of motion were better than those in the control group(P<0.05,P<0.01).In the functional evaluation,the interaction effects of the TBHM group in all dimensions of the KOOS score and TUGT were statistically significant(P<0.05,P<0.01).Post-hoc simple effect analysis confirmed that there were significant differences in the above indicators between the two groups after intervention(P<0.05),and all indicators showed a significant main effect of time(P<0.01),suggesting that the intervention measures had continuous and cumulative curative effects.CONCLUSION TBHM effectively improves joint function and quality of life in KOA patients by restoring dynamic equilibrium in soft tissue tension and patellar mobility,ultimately achieving the therapeutic goal of concurrent tissue-bone management.展开更多
The electrically assisted(EA)deformation process has received considerable attention in recent years,ac-companied by research on current-induced deformation mechanisms.However,there are still challenges in eliminating...The electrically assisted(EA)deformation process has received considerable attention in recent years,ac-companied by research on current-induced deformation mechanisms.However,there are still challenges in eliminating thermal effects,which have prevented a comprehensive understanding of the underlying current-induced mechanisms.Opting for a single crystal(SC)in research provides advantages in decou-pling the nonthermal effect of electric current at smaller scales and eliminating the complex interactions that exist in polycrystalline materials.Therefore,the innovation of this work lies in decoupling the non-thermal effect of electric current and conducting a comprehensive analysis of anisotropic deformation and mechanisms within a Ni-based SC with different crystallographic axes and various current directions dur-ing electrically assisted tensile simulation.A significant tension axis direction in the SC during EA tension was induced by the combination of a higher current direction factor(|cosθ|)and a dimensionless factor for the current density(|J^(α)/J_(0)^(α)|)along the[100]axis.The stress drop within the SC due to the nonthermal effect of electric current generally increased with increasing current direction.This was attributed to the increased dislocation density differences and decreased temperature.The increased stress anisotropy of the SC at a current direction of 45°was attributed to fewer activated(111)slip systems and the pinning effect of more dislocations within these systems.This study advances our understanding of the thermal and nonthermal effects of electric current and offers valuable insights for the informed application of EA deformations in industrial and aerospace settings with SC superalloys.展开更多
Beyond modern trade tensions and diplomatic milestones,Europe and China’s profound connection stems from a 3,000-year interplay of ideas,goods,and values,shaping their intertwined visions of governance,equality,and s...Beyond modern trade tensions and diplomatic milestones,Europe and China’s profound connection stems from a 3,000-year interplay of ideas,goods,and values,shaping their intertwined visions of governance,equality,and societal progress.展开更多
This paper examines the complex relationship between secular and religious communities in Israel,highlighting the socio-political tensions that arise from competing cultural norms and governance frameworks.Secular Jew...This paper examines the complex relationship between secular and religious communities in Israel,highlighting the socio-political tensions that arise from competing cultural norms and governance frameworks.Secular Jews,who constitute a significant portion of the population,advocate for civil liberties,the separation of religion and state,and the integration of ultra-Orthodox communities into broader society.In contrast,religious groups exert substantial influence within coalition governments,often obstructing the implementation of secular policies and exacerbating political instability.The discussion emphasizes the challenges posed by Israel’s unique legal framework,which intertwines Jewish identity with state governance,thereby complicating the principles of democracy and religious freedom.Key legislation,such as the Law of Return and the Law of the Rabbinical Courts,grants religious authorities substantial control over personal status issues,leading to ongoing disputes over rights and representation.The paper argues for the necessity of egalitarian pluralism as a framework for dialogue,aiming to bridge the divide between secular and religious communities.Fostering mutual respect and understanding is essential for achieving social cohesion and strengthening Israel’s commitment to being both a Jewish and democratic state.展开更多
This study aims to optimize biosurfactant production by Streptomyces gobitricini strain BS-2.After the initial screening,the effective factors on the production of biosurfactant were investigated with the two-level fa...This study aims to optimize biosurfactant production by Streptomyces gobitricini strain BS-2.After the initial screening,the effective factors on the production of biosurfactant were investigated with the two-level factorial statistical.The physical and chemical features and structure of the biosurfactant crafted were analyzed using FTIR,CHNS,EDX,and SEM.The extracted biosurfactant resulted in a decrease in interfacial tension from 72 mN/m to 29 mN/m,with a critical micelle concentration(CMC)of 300 mg/mL.The optimum medium for biosurfactant production that led to utmost diminution in culture broth surface tension(29 mN/m)was:crude oil(1.5%,v/v),hydrolyzed protein(1 g/L),yeast extract(0.5 g/L),molasses(1.5 g/L)and olive oil(1%v/v).The glycolipid organization of the microbial surfactant was confirmed via FTIR,CHNS,EDX,and SEM analysis.Analysis using GC indicated that the presence of biosurfactant increased crude oil degradation by S.gobitricini strain BS-2 dramatically(87%)and this bacterium effectively degraded most of its alkane components.Furthermore,the glycolipid biosurfactant displayed significant development repression against therapeutic bacterial microbes.In summary,the glycolipid biosurfactant produced by S.gobitricini strain BS-2 exhibited diverse functional properties and showed promise for potential biomedical and biotechnological applications.展开更多
The Italian textile machinery sector,renowned for its technological excellence and innovative capacity,continues to navigate a complex global market with a strategic emphasis on digitalization,sustainability,and stron...The Italian textile machinery sector,renowned for its technological excellence and innovative capacity,continues to navigate a complex global market with a strategic emphasis on digitalization,sustainability,and strong customer partnerships.Marco Salvade’,President of ACIMIT,provided insights into the industry’s performance,key trends,and future directions.In the first quarter of 2025,Italian textile machinery exports saw a 6%decrease compared to the same period in 2024,totaling€363 million.This dip reflects ongoing geopolitical tensions and a cautious approach among global clients toward new investments.Despite these challenges,Italian manufacturers maintain a strong reputation for technological leadership and resilience.展开更多
The U.S.imposition of high tariffs on Chinese goods has triggered short-term strains on China’s exports.At the same time,it has also accelerated its strategic pivot toward technological self-reliance,regional integra...The U.S.imposition of high tariffs on Chinese goods has triggered short-term strains on China’s exports.At the same time,it has also accelerated its strategic pivot toward technological self-reliance,regional integration,and domestic demand expansion.展开更多
Model calculations and laboratory experiments were conducted to investigate the influence of surface tension of the molten steel on the agglomeration trend of Al_(2)O_(3) inclusions.The agglomeration trends of inclusi...Model calculations and laboratory experiments were conducted to investigate the influence of surface tension of the molten steel on the agglomeration trend of Al_(2)O_(3) inclusions.The agglomeration trends of inclusions were compared using the calculated attractiveness.When the S content in the steel increased from 2.7×10^(-6) to 789×10^(-6),the surface tension of the molten steel decreased from 1.91 to 1.39 N/m,while the attractive force between inclusions increased from 5×10^(-18) to 5×10^(-16) N,and the critical collision distance of Al_(2)O_(3) inclusions gradually increased from 30 to 70μm.A model of the relationship between the capillary force of inclusions and S content in steel was established.It was found that the capillary force calculated by the model showed the same trend as the attractive force obtained from experiments,and an increase in the S content promoted the attraction between inclusions.展开更多
In an era marked by rising protectionism and geopolitical tensions,the world faces a stark choice:embrace multilateral cooperation or succumb to unilateral hegemony.The United States’punitive tariff policies have exp...In an era marked by rising protectionism and geopolitical tensions,the world faces a stark choice:embrace multilateral cooperation or succumb to unilateral hegemony.The United States’punitive tariff policies have exposed the negative effect of economic coercion and isolation.Meanwhile,China’s commitment to openness,innovation,and shared prosperity offers a contrast,a testament to the enduring vitality of multilateralism and global integration.展开更多
The interfacial strength has a significant impact on mechanical properties of diamond composites.In this work,polycrystalline diamonds(PCDs)with medium-entropy alloy(MEA)binders and traditional Co binder were prepared...The interfacial strength has a significant impact on mechanical properties of diamond composites.In this work,polycrystalline diamonds(PCDs)with medium-entropy alloy(MEA)binders and traditional Co binder were prepared at high-pressure and high-temperature.Microstructures and interfacial strengths are carefully characterized using TEM.The results show that diamond particles are well bonded to form skeletons in all PCDs.The interfaces between MEA binders and diamond can be fully coherent.Due to the effect of Cr element and Cr-carbide,the PCD with Co_(50) Ni_(40) Fe_(10)-Cr_(3)C_(2) binder exhibits the highest interfacial bonding strength(1176.6 MPa)and highest fracture toughness(9.97 MPa m^(1/2)).The mechanical analyses indicate that both the interface and diamond skeleton have important effects on the fracture toughness of PCD.The interface with a higher bonding strength,a higher engineering strain and a higher elastic modulus can endure more stress,thereby improving the fracture toughness.展开更多
In the first half of 2025,the global textile machinery market continued to face significant headwinds,including economic slowdown,persistent inflation,and dampened consumer sentiment.According to Dr.Harald Weber,Manag...In the first half of 2025,the global textile machinery market continued to face significant headwinds,including economic slowdown,persistent inflation,and dampened consumer sentiment.According to Dr.Harald Weber,Managing Director of the VDMA Textile Machinery Association,German exports of textile machinery and accessories saw a yearon-year decrease of approximately 9%between January and May.This trend was not unique to Germany,as exports from all European countries also declined amid ongoing geopolitical tensions and unpredictable trade policies.Despite these challenges,the incoming orders are bottoming out,potentially signaling the beginning of an industry recovery.However,the protectionist policies have contributed to a cautious investment climate worldwide.And the protectionism is not limited to the U.S.,with subsidies and other unfair advantages for domestic companies distorting competition in multiple regions.Now,trade barriers are the most pressing challenge for the global textile industry,urging manufacturers to reduce strategic dependencies to mitigate risks.展开更多
Ice cover on transmission lines is a significant issue that affects the safe operation of the power system.Accurate calculation of the thickness of wire icing can effectively prevent economic losses caused by ice disa...Ice cover on transmission lines is a significant issue that affects the safe operation of the power system.Accurate calculation of the thickness of wire icing can effectively prevent economic losses caused by ice disasters and reduce the impact of power outages on residents.However,under extreme weather conditions,strong instantaneous wind can cause tension sensors to fail,resulting in significant errors in the calculation of icing thickness in traditional mechanics-based models.In this paper,we propose a dynamic prediction model of wire icing thickness that can adapt to extreme weather environments.The model expands scarce raw data by the Wasserstein Generative Adversarial Network with Gradient Penalty(WGAN-GP)technique,records historical environmental information by a recurrent neural network,and evaluates the ice warning levels by a classifier.At each time point,the model diagnoses whether the current sensor failure is due to icing or strong winds.If it is determined that the wire is covered with ice,the icing thickness will be calculated after the wind-induced tension is removed from the ice-wind coupling tension.Our new model was evaluated using data from the power grid in an area with extreme weather.The results show that the proposed model has significant improvements in accuracy compared with traditional models.展开更多
Cranes used at sea have some shortcomings in terms of flexibility,efficiency,and safety.Therefore,a floating multi-robot coordinated towing system is planned to fulfill the offshore towing requirements.It is difficult...Cranes used at sea have some shortcomings in terms of flexibility,efficiency,and safety.Therefore,a floating multi-robot coordinated towing system is planned to fulfill the offshore towing requirements.It is difficult to study the stability of a floating multi-robot coordinated towing system by ancient strategies.First,the minimum tension of the rope and the minimum singular value of the stiffness matrix were separately used to analyze the load stability.The advantages and disadvantages of the two methods were discussed.Then,the two stability analysis methods were normalized and weighted to obtain the method based on minimum tension and minimum singular to comprehensively analyze the stability of the load.Finally,the effect of different weighting coefficients on the load stability was analyzed,which led to a reasonable weighting coefficient to evaluate the load stability by comparing with a single analysis method.The research results provide a basis for the motion planning and coordinated control of the towing system.展开更多
文摘The authors investigate the failure modes surrounding over-stressed tunnels in rock.Three lines of investigation are employed:failure in over-stressed three-dimensional(3D) models of tunnels bored under 3D stress,failure modes in two-dimensional(2D) numerical simulations of 1000 m and 2000 m deep tunnels using FRACOD,both in intact rock and in rock masses with one or two joint sets,and finally,observations in TBM(tunnel boring machine) tunnels in hard and medium hard massive rocks.The reason for 'stress-induced' failure to initiate,when the assumed maximum tangential stress is approximately(0.4-0.5)σ_c(UCS,uniaxial compressive strength) in massive rock,is now known to be due to exceedance of a critical extensional strain which is generated by a Poisson's ratio effect.However,because similar 'stress/strength' failure limits are found in mining,nuclear waste research excavations,and deep road tunnels in Norway,one is easily misled into thinking of compressive stress induced failure.Because of this,the empirical SRF(stress reduction factor in the Q-system) is set to accelerate as the estimated ratio σ_(θmax)/σ_c >> 0.4.In mining,similar 'stress/strength' ratios are used to suggest depth of break-out.The reality behind the fracture initiation stress/strength ratio of '0.4' is actually because of combinations of familiar tensile and compressive strength ratios(such as 10) with Poisson's ratio(say0.25).We exceed the extensional strain limits and start to see acoustic emission(AE) when tangential stress σθ ≈ 0.4σc,due to simple arithmetic.The combination of 2D theoretical FRACOD models and actual tunnelling suggests frequent initiation of failure by 'stable' extensional strain fracturing,but propagation in 'unstable' and therefore dynamic shearing.In the case of very deep tunnels(and 3D physical simulations),compressive stresses may be too high for extensional strain fracturing,and shearing will dominate,both ahead of the face and following the face.When shallower,the concept of 'extensional strain initiation but propagation' in shear is suggested.The various failure modes are richly illustrated,and the inability of conventional continuum modelling is emphasized,unless cohesion weakening and friction mobilization at different strain levels are used to reach a pseudo state of yield,but still considering a continuum.
基金supported by the National Natural Science Foundation of China(12072136).
文摘Research on the mechanical–electrical properties is crucial for designing and preparing high-temperature superconducting(HTS)cables.Various winding core structures can influence the mechanical–electrical behavior of cables,but the impact of alterations in the winding core structure on the mechanical–electrical behavior of superconducting cables remains unclear.This paper presents a 3D finite element model to predict the performance of three cables with different core structures when subjected to transverse compression and axial tension.The three cables analyzed are CORC(conductor-on-round-core),CORT(conductor-on-round-tube),and HFRC(conductor-on-spiral-tube).A parametric analysis is carried out by varying the core diameter and inner-to-outer diameter ratio.Results indicate that the CORT cable demonstrates better performance in transverse compression compared to the CORC cable,aligning with experimental data.Among the three cables,the HFRC cables exhibit the weakest resistance to transverse deformation.However,the HFRC cable demonstrates superior tensile deformation resistance compared to the CORT cable,provided that the transverse compression properties are maintained.Finite element results also show that the optimum inner-to-outer diameter ratios for achieving the best transverse compression performance are approximately 0.8 for CORT cables and 0.6 for HFRC cables.Meanwhile,the study explores the effect of structural changes in HTS cable winding cores on their electromagnetic properties.It recommends utilizing small tape gaps,lower frequencies,and spiral core construction to minimize eddy losses.The findings presented in this paper offer valuable insights for the commercialization and practical manufacturing of HTS cables.
基金financially supported by the National Key Research and Development Program of China(Grant No.2023YFC2811600)the National Natural Science Foundation of China(Grant Nos.52301349 and 52088102)+1 种基金the Qingdao Post-Doctorate Science Fund(No.QDBSH20220202070)the Major Scientific and Technological Innovation Project of Shandong Province(Grant No.2019JZZY010820).
文摘A deep-sea mining riser is a crucial component of the system used to lift seafloor mineral resources to the vessel.It is prone to damage and failure because of harsh environmental conditions and internal fluid erosion.Furthermore,damage can impact the response characteristics of the riser,but varying environmental loadings easily mask it.Thus,distin-guishing between riser damage and environmental effects poses a considerable challenge.To address this issue,a cantilevered model is created for a deep-sea mining riser via the concentrated mass method,and a time-domain analytical strategy is developed.The vortex-induced vibration(VIV)response characteristics of the riser are initially examined,considering various damage conditions and flow velocities.The study results revealed four primary observations:(a)effective tension can serve as a reliable indicator for identifying damage at lower velocities;(b)there are noticeable differences in displacement between the healthy and damaged risers in the in-line direction rather than the cross-flow direction;(c)frequency characteristics can more effectively distinguish the damage conditions at high flow velocities,with the mean square frequency and frequency variance being more effective than the centroid frequency and root variance frequency;(d)displacement differences are more sensitive to damage occurring near the top and bottom of the riser,while both velocity variations and structural damage can influence displacements,especially in regions between modal nodes.The vibrational behavior and damage indicators are clarified for structural health monitoring of deep-sea mining risers during lifting operations.
基金supported by The National Natural Science Foundation of China(Grant Nos.12272411 and 42007259).
文摘Understanding the mesoscopic tensile fracture damage of rock is the basis of evaluating the deterioration process of mechanical properties of heat-damaged rock. For this, tensile tests of rocks under high-temperature treatment were conducted with a ϕ75 mm split Hopkinson tension bar (SHTB) to investigate the mesoscopic fracture and damage properties of rock. An improved scanning electron microscopy (SEM) experimental method was used to analyze the tensile fracture surfaces of rock samples. Qualitative and quantitative analyses were performed to assess evolution of mesoscopic damage of heat-damaged rock under tensile loading. A constitutive model describing the mesoscopic fractal damage under thermo-mechanical coupling was established. The results showed that the high temperatures significantly reduced the tensile strength and fracture surface roughness of the red sandstone. The three-dimensional (3D) reconstruction of the fracture surface of the samples that experienced tensile failure at 900 °C showed a flat surface. The standard deviation of elevation and slope angle of specimen fracture surface first increased and then decreased with increasing temperature. The threshold for brittle fracture of the heat-damaged red sandstone specimens was 600 °C. Beyond this threshold temperature, local ductile fracture occurred, resulting in plastic deformation of the fracture surface during tensile fracturing. With increase of temperature, the internal meso-structure of samples was strengthened slightly at first and then deteriorated gradually, which was consistent with the change of macroscopic mechanical properties of red sandstone. The mesoscopic characteristics, such as the number, mean side length, maximum area, porosity, and fractal dimension of crack, exhibited an initial decline, followed by a gradual increase. The development of microcracks in samples had significant influence on mesoscopic fractal dimension. The mesoscopic fractal characteristics were used to establish a mesoscopic fractal damage constitutive model for red sandstone, and the agreement between the theoretical and experimental results validated the proposed model.
文摘Mooring cable tension is a crucial parameter for evaluating the safety and reliability of a floating platform mooring system.The real-time mooring tension in an actual marine environment has always been essential data that mooring system designers aim to acquire.To address the need for long-term continuous monitoring of mooring tension in deep-sea marine environments,this paper presents a mooring cable tension monitoring method based on the principle of direct mechanical measurement.The developed tension monitoring sensors were installed and applied in the mooring system of the"Yongle"scientific experimental platform.Over the course of one year,a substantial amount of in-situ tension monitoring data was obtained.Under wave heights of up to 1.24 m,the mooring tension on the floating platform reached 16.5 tons.Through frequency domain and time domain analysis,the spectral characteristics of mooring tension,including waveinduced force,slow drift force,and mooring cable elastic restoring force,were determined.The mooring cable elastic restoring force frequency was approximately half of that of the wave signal.Due to the characteristics of the hinge connection structure of the dual module floating platform,under some specific working conditions the wave-induced force was the maximum of the three different frequency forces,and restoring force was the smallest.
文摘The deformation and fracture of a third-generation single crystal superalloy during in-situ tension at room temperature were investigated at multiple scales by scanning electron microscope,electron back-scattered diffractometer,and transmission electron microscope to reveal the deformation and fracture mechanism during tension.The proportion of low angle boundaries(LABs)with angles from 2.5°to 5.5°increases during tension.The change in LABs is particularly pronounced after elongation over 7%.The initiation of microcracks is caused by{111}<110>slip systems.After initiation,the crack size along the stress direction increases whereas the size extension along slip systems is suppressed.The fracture mode of the alloy is quasi-cleavage fracture and the slip lines near the fracture are implicit at room temperature.
文摘Sodium cocoyl glycinate(SCG),an environmentally friendly anionic amino acid surfactant,is widely used in daily chemical products as an upgraded alternative to traditional surfactants.In this study,crude Camellia oleifera saponin(COS)was purified using AB-8 macroporous adsorption resin,and its composition and structure were analyzed.The effects of different mole fractions of COS(αCOS)on surface tension(γ),oil-water interfacial tension(IFT),emulsification,and foam properties of COS-SCG binary mixed systems were investigated in mixtures of SCG with purified COS.The stability ofγand foamability under diverse environmental conditions were also discussed.The results indicated that the COS-SCG system exhibited remarkable surface-active synergism.The minimum critical micelle concentration(cmc)of the mixed system was lower than that of SCG,and adding a small mole fraction of COS(1%-2%)induced a synergistic reduction ofγ.Specifically,the cmc andγwere 2.50×10-4 mol/L and 23.1 mN/m forαCOS=1%,respectively.The system exhibited exceptional IFT reduction capacity,achieving a minimum value of 1.42 mN/m atαCOS=10%.The mixed system reached a foaming volume(atαCOS=50%)and foam stability(atαCOS=75%)were 51.0 mL and 97.37%,respectively.Microscopic analysis further confirmed these outstanding foam properties.Moreover,the COS-SCG system displayed reducedγwith enhanced foaming volume under elevated temperatures(35-75℃)and salinity(0-20 g/L).However,acidic conditions and hard water compromised bothγstability and foamability.
文摘OBJECTIVE To investigate the intervention effects of tissue-bone homeostasis manipulation(TBHM)on peripatellar biomechanical parameters and knee joint function in knee osteoarthritis(KOA)patients.METHODS Sixty patients with KOA(Kellgren-Lawrence gradeⅡ-Ⅲ)were recruited from the Acupuncture-Moxibustion Rehabilitation Department,Anhui University of Chinese Medicine between October 2024 and May 2025.Participants were randomized into a TBHM group(n=30)or a transcutaneous electrical neuromuscular stimulation(TENS)group(n=30).Using two-way repeated measures ANOVA,biomechanical indicators,including rectus femoris tension,vastus medialis tension,vastus lateralis tension,patellar ligament tension,lateral patellar displacement(LPD),medial patellar displacement(MPD),normalized patellar mobility(LPD/patellar width[PW],MPD/PW),knee flexion range of motion,and functional indicators,including KOOS subscales,time up and go test(TUGT),were compared between groups at baseline and after 6 weeks of intervention.RESULTS After intervention,all biomechanical and knee joint function indicators in the TBHM group were significantly improved(P<0.05,P<0.01),while only the vastus medialis tension,TUGT and KOOS Pain,ADL and QoL scores in the control group were significantly improved(P<0.01).The improvement amplitudes of biomechanical indicators in the TBHM group,including rectus femoris tension,vastus lateralis tension,patellar ligament tension,MPD/PW,LPD/PW and knee flexion range of motion were better than those in the control group(P<0.05,P<0.01).In the functional evaluation,the interaction effects of the TBHM group in all dimensions of the KOOS score and TUGT were statistically significant(P<0.05,P<0.01).Post-hoc simple effect analysis confirmed that there were significant differences in the above indicators between the two groups after intervention(P<0.05),and all indicators showed a significant main effect of time(P<0.01),suggesting that the intervention measures had continuous and cumulative curative effects.CONCLUSION TBHM effectively improves joint function and quality of life in KOA patients by restoring dynamic equilibrium in soft tissue tension and patellar mobility,ultimately achieving the therapeutic goal of concurrent tissue-bone management.
基金National Science Fund for Distinguished Young Scholars(No.52225505)the National Sci-ence and Technology Major Project(No.J2019-VII-0014-0154)+1 种基金the National Natural Science Foundation of China(No.52005412)the Tianjin Natural Science Foundation of China-Multi-input key projects(No.22JCZDJC00650)for financial supports given to this research.
文摘The electrically assisted(EA)deformation process has received considerable attention in recent years,ac-companied by research on current-induced deformation mechanisms.However,there are still challenges in eliminating thermal effects,which have prevented a comprehensive understanding of the underlying current-induced mechanisms.Opting for a single crystal(SC)in research provides advantages in decou-pling the nonthermal effect of electric current at smaller scales and eliminating the complex interactions that exist in polycrystalline materials.Therefore,the innovation of this work lies in decoupling the non-thermal effect of electric current and conducting a comprehensive analysis of anisotropic deformation and mechanisms within a Ni-based SC with different crystallographic axes and various current directions dur-ing electrically assisted tensile simulation.A significant tension axis direction in the SC during EA tension was induced by the combination of a higher current direction factor(|cosθ|)and a dimensionless factor for the current density(|J^(α)/J_(0)^(α)|)along the[100]axis.The stress drop within the SC due to the nonthermal effect of electric current generally increased with increasing current direction.This was attributed to the increased dislocation density differences and decreased temperature.The increased stress anisotropy of the SC at a current direction of 45°was attributed to fewer activated(111)slip systems and the pinning effect of more dislocations within these systems.This study advances our understanding of the thermal and nonthermal effects of electric current and offers valuable insights for the informed application of EA deformations in industrial and aerospace settings with SC superalloys.
文摘Beyond modern trade tensions and diplomatic milestones,Europe and China’s profound connection stems from a 3,000-year interplay of ideas,goods,and values,shaping their intertwined visions of governance,equality,and societal progress.
文摘This paper examines the complex relationship between secular and religious communities in Israel,highlighting the socio-political tensions that arise from competing cultural norms and governance frameworks.Secular Jews,who constitute a significant portion of the population,advocate for civil liberties,the separation of religion and state,and the integration of ultra-Orthodox communities into broader society.In contrast,religious groups exert substantial influence within coalition governments,often obstructing the implementation of secular policies and exacerbating political instability.The discussion emphasizes the challenges posed by Israel’s unique legal framework,which intertwines Jewish identity with state governance,thereby complicating the principles of democracy and religious freedom.Key legislation,such as the Law of Return and the Law of the Rabbinical Courts,grants religious authorities substantial control over personal status issues,leading to ongoing disputes over rights and representation.The paper argues for the necessity of egalitarian pluralism as a framework for dialogue,aiming to bridge the divide between secular and religious communities.Fostering mutual respect and understanding is essential for achieving social cohesion and strengthening Israel’s commitment to being both a Jewish and democratic state.
基金Prince Sattam bin Abdulaziz University for funding this research work through the project number(No.PSAU/2023/01/27406).
文摘This study aims to optimize biosurfactant production by Streptomyces gobitricini strain BS-2.After the initial screening,the effective factors on the production of biosurfactant were investigated with the two-level factorial statistical.The physical and chemical features and structure of the biosurfactant crafted were analyzed using FTIR,CHNS,EDX,and SEM.The extracted biosurfactant resulted in a decrease in interfacial tension from 72 mN/m to 29 mN/m,with a critical micelle concentration(CMC)of 300 mg/mL.The optimum medium for biosurfactant production that led to utmost diminution in culture broth surface tension(29 mN/m)was:crude oil(1.5%,v/v),hydrolyzed protein(1 g/L),yeast extract(0.5 g/L),molasses(1.5 g/L)and olive oil(1%v/v).The glycolipid organization of the microbial surfactant was confirmed via FTIR,CHNS,EDX,and SEM analysis.Analysis using GC indicated that the presence of biosurfactant increased crude oil degradation by S.gobitricini strain BS-2 dramatically(87%)and this bacterium effectively degraded most of its alkane components.Furthermore,the glycolipid biosurfactant displayed significant development repression against therapeutic bacterial microbes.In summary,the glycolipid biosurfactant produced by S.gobitricini strain BS-2 exhibited diverse functional properties and showed promise for potential biomedical and biotechnological applications.
文摘The Italian textile machinery sector,renowned for its technological excellence and innovative capacity,continues to navigate a complex global market with a strategic emphasis on digitalization,sustainability,and strong customer partnerships.Marco Salvade’,President of ACIMIT,provided insights into the industry’s performance,key trends,and future directions.In the first quarter of 2025,Italian textile machinery exports saw a 6%decrease compared to the same period in 2024,totaling€363 million.This dip reflects ongoing geopolitical tensions and a cautious approach among global clients toward new investments.Despite these challenges,Italian manufacturers maintain a strong reputation for technological leadership and resilience.
文摘The U.S.imposition of high tariffs on Chinese goods has triggered short-term strains on China’s exports.At the same time,it has also accelerated its strategic pivot toward technological self-reliance,regional integration,and domestic demand expansion.
基金the National Natural Science Foundation of China(Grant No.U22A20171)the National Key Research and Development Program Project of China(2023YFB3709900)+1 种基金the China Baowu Low Carbon Metallurgical Innovation Fund(BWLCF202315)the Pangang-USTB Vanadium and Titanium Research Institute Research Project,the High Steel Center(HSC)at North China University of Technology,Yanshan University and University of Science and Technology Beijing,China.
文摘Model calculations and laboratory experiments were conducted to investigate the influence of surface tension of the molten steel on the agglomeration trend of Al_(2)O_(3) inclusions.The agglomeration trends of inclusions were compared using the calculated attractiveness.When the S content in the steel increased from 2.7×10^(-6) to 789×10^(-6),the surface tension of the molten steel decreased from 1.91 to 1.39 N/m,while the attractive force between inclusions increased from 5×10^(-18) to 5×10^(-16) N,and the critical collision distance of Al_(2)O_(3) inclusions gradually increased from 30 to 70μm.A model of the relationship between the capillary force of inclusions and S content in steel was established.It was found that the capillary force calculated by the model showed the same trend as the attractive force obtained from experiments,and an increase in the S content promoted the attraction between inclusions.
文摘In an era marked by rising protectionism and geopolitical tensions,the world faces a stark choice:embrace multilateral cooperation or succumb to unilateral hegemony.The United States’punitive tariff policies have exposed the negative effect of economic coercion and isolation.Meanwhile,China’s commitment to openness,innovation,and shared prosperity offers a contrast,a testament to the enduring vitality of multilateralism and global integration.
基金financially supported by the Regional Innova-tion and Development Joint Funds of the National Natural Science Foundation of China(No.U20A20236)the Central South Univer-sity Innovation-Driven Research Programme(No.2023CXQD030)the Huaqiao University Engineering Research Center of Brittle Materials Machining(MOE,No.2023IME-002).
文摘The interfacial strength has a significant impact on mechanical properties of diamond composites.In this work,polycrystalline diamonds(PCDs)with medium-entropy alloy(MEA)binders and traditional Co binder were prepared at high-pressure and high-temperature.Microstructures and interfacial strengths are carefully characterized using TEM.The results show that diamond particles are well bonded to form skeletons in all PCDs.The interfaces between MEA binders and diamond can be fully coherent.Due to the effect of Cr element and Cr-carbide,the PCD with Co_(50) Ni_(40) Fe_(10)-Cr_(3)C_(2) binder exhibits the highest interfacial bonding strength(1176.6 MPa)and highest fracture toughness(9.97 MPa m^(1/2)).The mechanical analyses indicate that both the interface and diamond skeleton have important effects on the fracture toughness of PCD.The interface with a higher bonding strength,a higher engineering strain and a higher elastic modulus can endure more stress,thereby improving the fracture toughness.
文摘In the first half of 2025,the global textile machinery market continued to face significant headwinds,including economic slowdown,persistent inflation,and dampened consumer sentiment.According to Dr.Harald Weber,Managing Director of the VDMA Textile Machinery Association,German exports of textile machinery and accessories saw a yearon-year decrease of approximately 9%between January and May.This trend was not unique to Germany,as exports from all European countries also declined amid ongoing geopolitical tensions and unpredictable trade policies.Despite these challenges,the incoming orders are bottoming out,potentially signaling the beginning of an industry recovery.However,the protectionist policies have contributed to a cautious investment climate worldwide.And the protectionism is not limited to the U.S.,with subsidies and other unfair advantages for domestic companies distorting competition in multiple regions.Now,trade barriers are the most pressing challenge for the global textile industry,urging manufacturers to reduce strategic dependencies to mitigate risks.
基金supported by the Science and Technology Project of State Grid Corporation of China(SGXJDK00GYJS2400035).
文摘Ice cover on transmission lines is a significant issue that affects the safe operation of the power system.Accurate calculation of the thickness of wire icing can effectively prevent economic losses caused by ice disasters and reduce the impact of power outages on residents.However,under extreme weather conditions,strong instantaneous wind can cause tension sensors to fail,resulting in significant errors in the calculation of icing thickness in traditional mechanics-based models.In this paper,we propose a dynamic prediction model of wire icing thickness that can adapt to extreme weather environments.The model expands scarce raw data by the Wasserstein Generative Adversarial Network with Gradient Penalty(WGAN-GP)technique,records historical environmental information by a recurrent neural network,and evaluates the ice warning levels by a classifier.At each time point,the model diagnoses whether the current sensor failure is due to icing or strong winds.If it is determined that the wire is covered with ice,the icing thickness will be calculated after the wind-induced tension is removed from the ice-wind coupling tension.Our new model was evaluated using data from the power grid in an area with extreme weather.The results show that the proposed model has significant improvements in accuracy compared with traditional models.
基金the National Natural Science Foundation of China(No.51965032)the Natural Science Foundation of Gansu Province(No.22JR5RA319)+1 种基金the Science and Technology Foundation of Gansu Province(No.21YF5WA060)the Excellent Doctoral Student Foundation of Gansu Province(No.23JRRA842)。
文摘Cranes used at sea have some shortcomings in terms of flexibility,efficiency,and safety.Therefore,a floating multi-robot coordinated towing system is planned to fulfill the offshore towing requirements.It is difficult to study the stability of a floating multi-robot coordinated towing system by ancient strategies.First,the minimum tension of the rope and the minimum singular value of the stiffness matrix were separately used to analyze the load stability.The advantages and disadvantages of the two methods were discussed.Then,the two stability analysis methods were normalized and weighted to obtain the method based on minimum tension and minimum singular to comprehensively analyze the stability of the load.Finally,the effect of different weighting coefficients on the load stability was analyzed,which led to a reasonable weighting coefficient to evaluate the load stability by comparing with a single analysis method.The research results provide a basis for the motion planning and coordinated control of the towing system.
