To enhance the deformation capacity of vertical support columns of underground structures and improve their overall seismic performance,a new truncated column connected by unbonded prestressed tendons is proposed,insp...To enhance the deformation capacity of vertical support columns of underground structures and improve their overall seismic performance,a new truncated column connected by unbonded prestressed tendons is proposed,inspired by the concepts of the toughness seismic resistance and rocking design.Although many experimental and numerical studies have focused on underground structures,research on the behavior of truncated columns remains limited.This paper develops threedimensional(3D)finite element(FE)models for various columns,including cast-in-place column(CIPC)and prestressed tendon truncated column(PTTC),to evaluate the effects of three parameters,including axial compression ratio(ACR),initial tendon stress,and the effect of hole diameter on mechanical performance—specifically deformation capacity,strength,residual deformation and gap width.The results indicate that the deformability and self-centering ability of the prestressed tendon truncated column is obviously superior to the cast-in-place column,but its strength was comparatively lower.The axial compression ratio has obvious effects on seismic performance,especially deformation and residual deformation,while initial tendon stress and hole diameter influence performance only in the case of a small axial compression ratio.This study systematically identifies the influence of various factors on seismic performance.Additionally,this study proposes a method to evaluate the self-centering capability of structures and establishes an empirical relationship between maximum recoverable deformation and the axial compression ratio.The developed numerical model can serve as a tool for future studies to predict the seismic responses of overall subway stations that feature truncated columns.展开更多
This study proposes a new post-tensioned precast bridge column(PT-PBC)with a socket connection.Compared to conventional PBCs connected by PT tendons,the combination of the PT tendons with the socket connection can avo...This study proposes a new post-tensioned precast bridge column(PT-PBC)with a socket connection.Compared to conventional PBCs connected by PT tendons,the combination of the PT tendons with the socket connection can avoid tensioning the PT tendons on site,which further accelerates construction speed while improving construction quality and safety.In addition,compared to conventional PBCs with a socket connection,a rocking interface can avoid the formation of a plastic hinge in a column,which greatly alleviates seismic damage to that area.One specimen for quasi-static testing is used to validate the feasibility of this connection type.Subsequently,finite element models(FEM)are established to systematically predict the responses of the proposed columns under lateral cyclic loading.The accuracy of the FEM is verified through quasistatic testing.Next,the influences of the key design parameters of the PT-PBC,including the area ratio and prestress level of the PT tendons,the area ratio of energy dissipation(ED)steel rebars,and the total axial compression ratio on the seismic performances of PT-PBC are systematically investigated.The use of shape memory alloy(SMA)rods as energy dissipation devices and their performances also are investigated.The results show that increasing the area ratio and prestress level of PT tendons has an overall positive impact on the self-centering capacity of the column.The prestress level of PT tendons should be kept between 35%and 55%,depending on different conditions.The total compression axial ratio of the columns should be maintained between 0.3 and 0.4.Both ED steel rebars and SMA rods can boost the column’s energy dissipation capacity,while SMA rods can reduce residual deformation due to their inherent mechanical properties.展开更多
Tendon-related diseases(TRDs)are increasingly common in the current aging society and impose a significant burden on patients.Despite therapeutic advances,the pathophysiology of TRDs remains poorly understood,hinderin...Tendon-related diseases(TRDs)are increasingly common in the current aging society and impose a significant burden on patients.Despite therapeutic advances,the pathophysiology of TRDs remains poorly understood,hindering effective clinical management.The macrophages are highly plastic immune cells involved in the maintenance of in vivo homeostasis and the injury-healing process.Their dual role in TRDs has been widely investigated,either promoting tenogenic and chondrogenic differentiation or amplifying inflammatory response,underscoring their therapeutic potential for TRDs treatment.Therefore,the review aims to summarize the roles of macrophages in the healing of TRDs,characterized by limited regenerative capacity,and examine strategies for the modulation of macrophage phenotypes to accelerate the regeneration process.Finally,we review applications involving macrophage modulation within the context of tissue engineering of TRDs,providing novel insights for the design of biomaterials-based targeted delivery systems.展开更多
Automation and intelligence have become the primary trends in the design of investment casting processes.However,the design of gating and riser systems still lacks precise quantitative evaluation criteria.Numerical si...Automation and intelligence have become the primary trends in the design of investment casting processes.However,the design of gating and riser systems still lacks precise quantitative evaluation criteria.Numerical simulation plays a significant role in quantitatively evaluating current processes and making targeted improvements,but its limitations lie in the inability to dynamically reflect the formation outcomes of castings under varying process conditions,making real-time adjustments to gating and riser designs challenging.In this study,an automated design model for gating and riser systems based on integrated parametric 3D modeling-simulation framework is proposed,which enhances the flexibility and usability of evaluating the casting process by simulation.Firstly,geometric feature extraction technology is employed to obtain the geometric information of the target casting.Based on this information,an automated design framework for gating and riser systems is established,incorporating multiple structural parameters for real-time process control.Subsequently,the simulation results for various structural parameters are analyzed,and the influence of these parameters on casting formation is thoroughly investigated.Finally,the optimal design scheme is generated and validated through experimental verification.Simulation analysis and experimental results show that using a larger gate neck(24 mm in side length) and external risers promotes a more uniform temperature distribution and a more stable flow state,effectively eliminating shrinkage cavities and enhancing process yield by 15%.展开更多
BACKGROUND Anterior cruciate ligament(ACL)reconstruction using bone-patellar tendon-bone(BPTB)autografts remains the gold standard for young,active individuals due to its superior biomechanical strength and bone-to-bo...BACKGROUND Anterior cruciate ligament(ACL)reconstruction using bone-patellar tendon-bone(BPTB)autografts remains the gold standard for young,active individuals due to its superior biomechanical strength and bone-to-bone healing.However,donor site morbidity,particularly anterior knee pain(AKP),limits its utilization despite its advantages.Various techniques have been proposed to reduce AKP,but they show variable outcomes and several limitations.AIM To assess the incidence and severity of AKP following BPTB ACL reconstruction using an autologous bone grafting technique.METHODS We conducted a retrospective observational study of 24 patients aged 20-45 years,who had primary ACL reconstruction with BPTB grafts.During surgery,autologous cancellous bone generated from tunnel drilling was used to fill the patellar and tibial donor site voids after graft fixation.All patients were followed up for at least twelve months.Using the Kujala Anterior Knee Pain Score,clinical outcomes were evaluated,including the pain-specific subcomponent.RESULTS With scores ranging from 86 to 100,the average overall Kujala score was 95.67±4.01.No patient scored below 85.There was no complication such as patellar fracture,tibial tuberosity fracture,or infection.Grouped data showed 20.8%of patients scored 100,whereas 54.2%scored between 95 and 99,and 25%scored between 86 and 94.One patient(4.2%)had an 8/10 pain subcomponent,whereas 23 patients(95.8%)had a 10/10.CONCLUSION This procedure is easy to incorporate into routine surgical practice,cost-effective and reproducible without requiring extra incisions or raising the patient’s surgical expenses.Excellent short-term results back up this technique.展开更多
In this study,the dynamics of the tendon/top tension riser(TTR)system of a tension-leg platform(TLP)are investigated through an experiment and by using absolute nodal coordinate formulation(ANCF).First,the model test ...In this study,the dynamics of the tendon/top tension riser(TTR)system of a tension-leg platform(TLP)are investigated through an experiment and by using absolute nodal coordinate formulation(ANCF).First,the model test of the TLP system is conducted in the water tank of Harbin Engineering University to examine the motion response of the TLP and the dynamic response characteristics of the tendon and TTR.The test scale ratio is set to 1:66.3.Then,on the basis of the ANCF,the stiffness,external load,and mass matrices of the element are deduced to establish the motion equation of the tendon/riser.Finally,the static and dynamic characteristics of the tendon/TTR system of TLP are analyzed systematically by using the ANCF method.The results are compared with commercial software and test results.The motion response of tendon/TTR is affected by the TLP movement and environmental load simultaneously.The analysis proves the effectiveness and accuracy of the ANCF method despite the low number of riser units,suggesting the superiority of the ANCF method for calculating the dynamics of tendon/riser in the field of ocean engineering.展开更多
Mechanical stress modulates bone formation and organization of the extracellular matrix(ECM),the interaction of which affects heterotopic ossification(HO).However,the mechanically sensitive cell populations in HO and ...Mechanical stress modulates bone formation and organization of the extracellular matrix(ECM),the interaction of which affects heterotopic ossification(HO).However,the mechanically sensitive cell populations in HO and the underlying mechanism remain elusive.Here,we show that the mechanical protein Polysyctin-1(PC1,Pkd1)regulates CTSK lineage tendon-derived mesenchymal stem cell(TDMSC)fate and ECM organization,thus affecting HO progression.First,we revealed that CTSK lineage TDMSCs are the major source of osteoblasts and fibroblasts in HO and are responsive to mechanical cues via single-cell RNA sequencing analysis and experiments with a lineage tracing mouse model.Moreover,we showed that PC1 mediates the mechanosignal transduction of CTSK lineage TDMSCs to regulate osteogenic and fibrogenic differentiation and alters the ECM architecture by facilitating TAZ nuclear translocation.Conditional gene depletion of Pkd1 or Taz in CTSK lineage cells and pharmaceutical intervention in the PC1-TAZ axis disrupt osteogenesis,fibrogenesis and ECM organization,and consequently attenuate HO progression.These findings suggest that mechanically sensitive CTSK-lineage TDMSCs contribute to heterotopic ossification through PC1-TAZ signaling axis mediated cell fate determination and ECM organization.展开更多
Steel catenary riser represents the pioneering riser technology implemented in China’s deep-sea oil and gas opera-tions.Given the complex mechanical conditions of the riser,extensive research has been conducted on it...Steel catenary riser represents the pioneering riser technology implemented in China’s deep-sea oil and gas opera-tions.Given the complex mechanical conditions of the riser,extensive research has been conducted on its dynamic analysis and structural design.This study investigates a deep-sea oil and gas field by developing a coupled model of a semi-submersible platform and steel catenary riser to analyze it mechanical behavior under extreme marine condi-tions.Through multi-objective optimization methodology,the study compares and analyzes suspension point tension and touchdown point stress under various conditions by modifying the suspension position,suspension angle,and catenary length.The optimal configuration parameters were determined:a suspension angle of 12°,suspension position in the southwest direction of the column,and a catenary length of approximately 2000 m.These findings elucidate the impact of configuration parameters on riser dynamic response and establish reasonable parameter layout ranges for adverse sea conditions,offering valuable optimization strategies for steel catenary riser deployment in domestic deep-sea oil and gas fields.展开更多
This study examines the slug-induced vibration(SIV)response and fatigue behavior of offshore risers subjected to internal slug flow.A structural model incorporating internal slug flow dynamics is developed using the A...This study examines the slug-induced vibration(SIV)response and fatigue behavior of offshore risers subjected to internal slug flow.A structural model incorporating internal slug flow dynamics is developed using the Absolute Nodal Coordinate Formulation(ANCF)and a spatial-temporal density variation equation to analyze how slug flow parameters affect the SIV response of risers.Structural displacement,stress,and fatigue responses are systematically evaluated to characterize the structural behavior under SIV conditions.Longer slugs induce more pronounced traveling wave characteristics,while shorter slugs facilitate a mixed traveling-standing wave mode.Moreover,higher slug frequencies lead to increased fatigue accumulation,especially over an extended touchdown zone,thereby compromising the structural integrity of the riser.The findings yield valuable insights into the dynamic interactions between slug flow and riser response.This research advances the understanding of SIV mechanisms and provides a theoretical foundation for fatigue assessment and structural optimization,contributing to the safe and efficient design of offshore risers in deepwater environments.展开更多
An experimental analysis of the slug-induced vibration(SIV)of a flexible catenary riser with an aspect ratio of 130 is reported in this work.The vibration responses and internal slug flow details at different gas-liqu...An experimental analysis of the slug-induced vibration(SIV)of a flexible catenary riser with an aspect ratio of 130 is reported in this work.The vibration responses and internal slug flow details at different gas-liquid ratios(Q_(g)/Q_(l))and mixture velocities(vm)are non-intrusively and simultaneously captured by high-speed cameras.Both the in-plane and out-of-plane responses of the catenary riser are excited in all considered cases.The slug flow characteristics,including translational velocities,slug lengths,recurrence frequencies,and pressure variations,are analyzed and dis-cussed,as are the dynamic responses of the riser in terms of the amplitudes,space-varying frequency,and modal weight.The dominant modal response based on the root-mean-square amplitude profiles does not match that based on the dominant frequency.Three mode switching types are identified based on the RMS amplitude profiles and the dominant frequency.When vm is small,no mode switching(NMS)is observed in either the in-plane or out-of-plane responses.For mode switching I(MS I),the switching between the first and second modes in the in-plane response is induced by slug flow with different recurrence frequencies in cases of large Q_(g)/Q_(l).However,there is no mode switching in the out-of-plane response.The switching between the first and third modes for the in-plane response and the second and fourth modes for the out-of-plane response(MS II)occurs in cases of relatively high vm and low Q_(g)/Q_(l).展开更多
This study examines the adaptive boundary control problem of flexible marine riser with internal flow coupling.The dynamic model of the flexible marine riser system with internal flow coupling is derived using the Ham...This study examines the adaptive boundary control problem of flexible marine riser with internal flow coupling.The dynamic model of the flexible marine riser system with internal flow coupling is derived using the Hamiltonian principle.An analysis of internal flow’s influence on the vibration characteristics of flexible marine risers is conducted.Then,for the uncertain environmental disturbance,the adaptive fuzzy logic system is introduced to dynamically approximate the boundary disturbance,and a robust adaptive fuzzy boundary control is proposed.The uniform boundedness of the closed-loop system is proved based on Lyapunov theory.The well-posedness of the closed-loop system is proved by operator semigroup theory.The proposed control’s effectiveness is validated through comparison with existing control methods.展开更多
Mitigating vortex-induced vibrations(VIV)in flexible risers represents a critical concern in offshore oil and gas production,considering its potential impact on operational safety and efficiency.The accurate predictio...Mitigating vortex-induced vibrations(VIV)in flexible risers represents a critical concern in offshore oil and gas production,considering its potential impact on operational safety and efficiency.The accurate prediction of displacement and position of VIV in flexible risers remains challenging under actual marine conditions.This study presents a data-driven model for riser displacement prediction that corresponds to field conditions.Experimental data analysis reveals that the XGBoost algorithm predicts the maximum displacement and position with superior accuracy compared with Support vector regression(SVR),considering both computational efficiency and precision.Platform displacement in the Y-direction demonstrates a significant positive correlation with both axial depth and maximum displacement magnitude.The fourth point displacement exhibits the highest contribution to model prediction outcomes,showing a positive influence on maximum displacement while negatively affecting the axial depth of maximum displacement.Platform displacement in the X-and Y-directions exhibits competitive effects on both the riser’s maximum displacement and its axial depth.Through the implementation of XGBoost algorithm and SHapley Additive exPlanation(SHAP)analysis,the model effectively estimates the riser’s maximum displacement and its precise location.This data-driven approach achieves predictions using minimal,readily available data points,enhancing its practical field applications and demonstrating clear relevance to academic and professional communities.展开更多
The carcass layer is the innermost structure of flexible marine risers and is responsible for resisting external pressure.It has an“S”section with a spiral interlocking feature.After the multi-pass roll forming of a...The carcass layer is the innermost structure of flexible marine risers and is responsible for resisting external pressure.It has an“S”section with a spiral interlocking feature.After the multi-pass roll forming of a flat steel strip,a carcass layer is formed by lock forming.During roll forming,the steel strip undergoes significant plastic deformation,and its local area accumulates residual stress owing to multiple loading and unloading cycles.These phenomena complicate the design and analysis of the carcass layer multi-pass roll forming(CLMRF)process and cause issues in the carcass layer during manufacturing,such as strip fracture and low forming quality.Thus,herein,CLMRF was investigated to clarify the stress distribution,and a parameter analysis was performed.First,the CLMRF process was designed on the basis of classical roll-forming design theory.Second,a finite element model was established,and CLMRF was simulated.Third,the distributions of the forming stress and residual stress of the strip during CLMRF were investigated.Finally,the influences of the strip thickness,roll gap,roll distance,and angular increment were investigated.The conclusions of this study can be used to provide technical guidance in the manufacturing of flexible risers.展开更多
BACKGROUND Thumb replantation following complete traumatic avulsion requires complex techniques to restore function,especially in cases of avulsion at the level of the metacarpophalangeal joint(MCP I)and avulsion of t...BACKGROUND Thumb replantation following complete traumatic avulsion requires complex techniques to restore function,especially in cases of avulsion at the level of the metacarpophalangeal joint(MCP I)and avulsion of the flexor pollicis longus(FPL)at the musculotendinous junction.Possible treatments include direct tendon suture or tendon transfer,most commonly from the ring finger.To optimize function and avoid donor finger complications,we performed thumb replantation with flexion restoration using brachioradialis(BR)tendon transfer with palmaris longus(PL)tendon graft.CASE SUMMARY A 20-year-old left-handed male was admitted for a complete traumatic left thumb amputation following an accident while sliding from the top of a handrail.The patient presented with skin and bone avulsion at the MCP I,avulsion of the FPL tendon at the musculotendinous junction(zone 5),avulsion of the extensor pollicis longus tendon(zone T3),and avulsion of the thumb’s collateral arteries and nerves.The patient was treated with two stage thumb repair.The first intervention consisted of thumb replantation with MCP I arthrodesis,resection of avulsed FPL tendon and implantation of a silicone tendon prosthesis.The second intervention consisted of PL tendon graft and BR tendon transfer.Follow-up at 10 months showed good outcomes with active interphalangeal flexion of 70°,grip strength of 45 kg,key pinch strength of 15 kg and two-point discrimination threshold of 4 mm.CONCLUSION Flexion restoration after complete thumb amputation with FPL avulsion at the musculotendinous junction can be achieved using BR tendon transfer with PL tendon graft.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
As oil and gas exploration moves into deeper waters,marine risers are subjected to increasingly complex service conditions,including vessel motions,ocean currents,seabed-soil interactions,and internal flow effects.Thi...As oil and gas exploration moves into deeper waters,marine risers are subjected to increasingly complex service conditions,including vessel motions,ocean currents,seabed-soil interactions,and internal flow effects.This work establishes a dynamic behavior model of steel catenary risers(SCRs)with varying curvatures subjected to internal flow and external currents and considers the effects of pipe-soil interactions on the curvature profile.The governing equation is solved via the generalized integral transform technique(GITT),which yields a semi-analytical solution of a high-order nonlinear partial differential equation.Parametric studies are then performed to analyze the effects of varying curvature on the vibration frequency and amplitude of SCRs.The vibration frequency and amplitude increase with the touchdown angle and hang-off angle,although the effect of the hang-off angle is negligible.Additionally,as the curvature increases along the centerline axis,the position of the maximum amplitude of the SCR moves upward.展开更多
With the increasing exploration of oil and gas into deep waters,the necessity for material development increases for lighter conduits such as composite marine risers,in the oil and gas industry.To understand the resea...With the increasing exploration of oil and gas into deep waters,the necessity for material development increases for lighter conduits such as composite marine risers,in the oil and gas industry.To understand the research knowledge on this novel area,there is a need to have a bibliometric analysis on composite marine risers.A research methodology was developed whereby the data retrieval was from SCOPUS database from 1977–2023.Then,VOSviewer was used to visualize the knowledge maps.This study focuses on the progress made by conducting knowledge mapping and scientometric review on composite marine risers.This scientometric analysis on the subject shows current advances,geographical activities by countries,authorship records,collaborations,funders,affiiliations,co‑occurrences,and future research areas.It was observed that the research trends recorded the highest publication volume in the U.S.A.,but less cluster affiiliated,as it was followed by countries like the U.K.,China,Nigeria,Australia and Singapore.Also,thisfiield has more conference papers than journal papers due to the challenge of adaptability,acceptance,qualifiication,and application of composite marine risers in the marine industry.Hence,there is a need for more collaborations on composite marine risers and more funding to enhance the research trend.展开更多
Tendon adhesion,a prevalent complication affecting over 30%of patients after a tendon injury or surgery,results in joint stiffness and impaired mobility.Although current treatments facilitate tendon repair,they are of...Tendon adhesion,a prevalent complication affecting over 30%of patients after a tendon injury or surgery,results in joint stiffness and impaired mobility.Although current treatments facilitate tendon repair,they are often insufficient in preventing adhesions and promoting optimal healing outcomes.To address these challenges,we developed an oriented cryostructured silk fibroin bandage(OCSFB)using the directional freeze-casting methodology.In vitro studies demonstrated that OCSFB provided a favorable microenvironment for cell viability,proliferation,and alignment,concurrently upregulating the expression of tendon-specific genes.In a rat Achilles tendon model,OCSFB significantly reduced adhesion formation and improved tendon healing.RNA-seq analysis further revealed modulation of cell adhesion molecules,substantiating its role in tissue regeneration.The integration of silk fibroin biocompatibility with a unique microstructure that facilitates cellular adhesion and proliferation renders OCSFB a promising approach for mitigating tendon adhesions and improving repair outcomes,establishing it as a robust candidate for clinical application.展开更多
BACKGROUND To treat flexor pollicis longus(FPL)muscle function loss,the 4th flexor digitorum superficialis(FDS)to the FPL tendon transfer is preferred as a reconstruction method.Various complications can occur during ...BACKGROUND To treat flexor pollicis longus(FPL)muscle function loss,the 4th flexor digitorum superficialis(FDS)to the FPL tendon transfer is preferred as a reconstruction method.Various complications can occur during transfer.However,median nerve neuropathy has not been reported yet.We present a case of median nerve neuropathy caused by irritation of suture knots of the 4th FDS to the FPL tendon transfer with a review of the literature.CASE SUMMARY A 52-year-old male patient presented with paresthesia along median nerve distribution of right hand after tendon transfer.He complained of right thumb flexion limitation due to FPL function loss so authors performed the 4th FDS to FPL transfer using Pulvertaft weave technique.FPL function loss was due to adhesion resulting from repeated surgery of radius shaft.He had a history of radius shaft open fracture 9 years ago and nonunion 7 years ago.During surgery,FPL muscle was severely adhered and indistinguishable.However,tendon continuity remained intact.After tendon transfer,he experienced paresthesia along median nerve distribution upon movement of thumb.He was diagnosed with median nerve neuropathy caused by irritation of tendon suture knots.Exploration was then performed.The median nerve was irritated by suture knots of transferred tendon.Thus,knots were removed.Twelve months later,he demonstrated thumb flexion of 80°.Additionally,median nerve neuropathy symptoms fully resolved.CONCLUSION Median nerve neuropathy can occur after tendon transfer from irritation of suture knots.Covering knots using surrounding tissue is recommended.展开更多
This article offers additional clinical and biomechanical insights into using the peroneus longus tendon(PLT)autograft in posterior cruciate ligament recon-struction.While recent studies report favorable knee outcomes...This article offers additional clinical and biomechanical insights into using the peroneus longus tendon(PLT)autograft in posterior cruciate ligament recon-struction.While recent studies report favorable knee outcomes,concerns remain regarding donor site morbidity.The PLT plays a key role in foot biomechanics,and its harvesting may lead to subtle changes,as suggested by imaging and pe-dobarographic studies.Tendon regeneration may limit long-term morbidity,but further studies are needed.We recommend that future research include gait analysis,long-term follow-up,and insights from anterior cruciate ligament li-terature.展开更多
基金National Natural Science Foundation of China under Grant Nos.52478488 and 51908013the National Key Basic Research and Development Program of China under Grant No.2018YFC1504305。
文摘To enhance the deformation capacity of vertical support columns of underground structures and improve their overall seismic performance,a new truncated column connected by unbonded prestressed tendons is proposed,inspired by the concepts of the toughness seismic resistance and rocking design.Although many experimental and numerical studies have focused on underground structures,research on the behavior of truncated columns remains limited.This paper develops threedimensional(3D)finite element(FE)models for various columns,including cast-in-place column(CIPC)and prestressed tendon truncated column(PTTC),to evaluate the effects of three parameters,including axial compression ratio(ACR),initial tendon stress,and the effect of hole diameter on mechanical performance—specifically deformation capacity,strength,residual deformation and gap width.The results indicate that the deformability and self-centering ability of the prestressed tendon truncated column is obviously superior to the cast-in-place column,but its strength was comparatively lower.The axial compression ratio has obvious effects on seismic performance,especially deformation and residual deformation,while initial tendon stress and hole diameter influence performance only in the case of a small axial compression ratio.This study systematically identifies the influence of various factors on seismic performance.Additionally,this study proposes a method to evaluate the self-centering capability of structures and establishes an empirical relationship between maximum recoverable deformation and the axial compression ratio.The developed numerical model can serve as a tool for future studies to predict the seismic responses of overall subway stations that feature truncated columns.
基金Natural Science Foundation of China under Grant No.52178449,the Beijing Natural Science Foundation under Grant No.8234060the Innovation Center of Beijing Association for Science and Technology。
文摘This study proposes a new post-tensioned precast bridge column(PT-PBC)with a socket connection.Compared to conventional PBCs connected by PT tendons,the combination of the PT tendons with the socket connection can avoid tensioning the PT tendons on site,which further accelerates construction speed while improving construction quality and safety.In addition,compared to conventional PBCs with a socket connection,a rocking interface can avoid the formation of a plastic hinge in a column,which greatly alleviates seismic damage to that area.One specimen for quasi-static testing is used to validate the feasibility of this connection type.Subsequently,finite element models(FEM)are established to systematically predict the responses of the proposed columns under lateral cyclic loading.The accuracy of the FEM is verified through quasistatic testing.Next,the influences of the key design parameters of the PT-PBC,including the area ratio and prestress level of the PT tendons,the area ratio of energy dissipation(ED)steel rebars,and the total axial compression ratio on the seismic performances of PT-PBC are systematically investigated.The use of shape memory alloy(SMA)rods as energy dissipation devices and their performances also are investigated.The results show that increasing the area ratio and prestress level of PT tendons has an overall positive impact on the self-centering capacity of the column.The prestress level of PT tendons should be kept between 35%and 55%,depending on different conditions.The total compression axial ratio of the columns should be maintained between 0.3 and 0.4.Both ED steel rebars and SMA rods can boost the column’s energy dissipation capacity,while SMA rods can reduce residual deformation due to their inherent mechanical properties.
基金supported by the Guangxi Natural Science Foundation(AD21220065 to JX)the National Natural Science Foundation of China(82102632 and 82160412 to JX)the Guangdong Basic and Applied Basic Research Foundation(2023A1515220072 to ZHD)。
文摘Tendon-related diseases(TRDs)are increasingly common in the current aging society and impose a significant burden on patients.Despite therapeutic advances,the pathophysiology of TRDs remains poorly understood,hindering effective clinical management.The macrophages are highly plastic immune cells involved in the maintenance of in vivo homeostasis and the injury-healing process.Their dual role in TRDs has been widely investigated,either promoting tenogenic and chondrogenic differentiation or amplifying inflammatory response,underscoring their therapeutic potential for TRDs treatment.Therefore,the review aims to summarize the roles of macrophages in the healing of TRDs,characterized by limited regenerative capacity,and examine strategies for the modulation of macrophage phenotypes to accelerate the regeneration process.Finally,we review applications involving macrophage modulation within the context of tissue engineering of TRDs,providing novel insights for the design of biomaterials-based targeted delivery systems.
基金financially supported by the National Key Research and Development Program of China (2022YFB3706802)。
文摘Automation and intelligence have become the primary trends in the design of investment casting processes.However,the design of gating and riser systems still lacks precise quantitative evaluation criteria.Numerical simulation plays a significant role in quantitatively evaluating current processes and making targeted improvements,but its limitations lie in the inability to dynamically reflect the formation outcomes of castings under varying process conditions,making real-time adjustments to gating and riser designs challenging.In this study,an automated design model for gating and riser systems based on integrated parametric 3D modeling-simulation framework is proposed,which enhances the flexibility and usability of evaluating the casting process by simulation.Firstly,geometric feature extraction technology is employed to obtain the geometric information of the target casting.Based on this information,an automated design framework for gating and riser systems is established,incorporating multiple structural parameters for real-time process control.Subsequently,the simulation results for various structural parameters are analyzed,and the influence of these parameters on casting formation is thoroughly investigated.Finally,the optimal design scheme is generated and validated through experimental verification.Simulation analysis and experimental results show that using a larger gate neck(24 mm in side length) and external risers promotes a more uniform temperature distribution and a more stable flow state,effectively eliminating shrinkage cavities and enhancing process yield by 15%.
文摘BACKGROUND Anterior cruciate ligament(ACL)reconstruction using bone-patellar tendon-bone(BPTB)autografts remains the gold standard for young,active individuals due to its superior biomechanical strength and bone-to-bone healing.However,donor site morbidity,particularly anterior knee pain(AKP),limits its utilization despite its advantages.Various techniques have been proposed to reduce AKP,but they show variable outcomes and several limitations.AIM To assess the incidence and severity of AKP following BPTB ACL reconstruction using an autologous bone grafting technique.METHODS We conducted a retrospective observational study of 24 patients aged 20-45 years,who had primary ACL reconstruction with BPTB grafts.During surgery,autologous cancellous bone generated from tunnel drilling was used to fill the patellar and tibial donor site voids after graft fixation.All patients were followed up for at least twelve months.Using the Kujala Anterior Knee Pain Score,clinical outcomes were evaluated,including the pain-specific subcomponent.RESULTS With scores ranging from 86 to 100,the average overall Kujala score was 95.67±4.01.No patient scored below 85.There was no complication such as patellar fracture,tibial tuberosity fracture,or infection.Grouped data showed 20.8%of patients scored 100,whereas 54.2%scored between 95 and 99,and 25%scored between 86 and 94.One patient(4.2%)had an 8/10 pain subcomponent,whereas 23 patients(95.8%)had a 10/10.CONCLUSION This procedure is easy to incorporate into routine surgical practice,cost-effective and reproducible without requiring extra incisions or raising the patient’s surgical expenses.Excellent short-term results back up this technique.
文摘In this study,the dynamics of the tendon/top tension riser(TTR)system of a tension-leg platform(TLP)are investigated through an experiment and by using absolute nodal coordinate formulation(ANCF).First,the model test of the TLP system is conducted in the water tank of Harbin Engineering University to examine the motion response of the TLP and the dynamic response characteristics of the tendon and TTR.The test scale ratio is set to 1:66.3.Then,on the basis of the ANCF,the stiffness,external load,and mass matrices of the element are deduced to establish the motion equation of the tendon/riser.Finally,the static and dynamic characteristics of the tendon/TTR system of TLP are analyzed systematically by using the ANCF method.The results are compared with commercial software and test results.The motion response of tendon/TTR is affected by the TLP movement and environmental load simultaneously.The analysis proves the effectiveness and accuracy of the ANCF method despite the low number of riser units,suggesting the superiority of the ANCF method for calculating the dynamics of tendon/riser in the field of ocean engineering.
基金National Natural Science Foundation of China(Grant Nos.82261160397,82272560)Central South University Research Programme of Advanced Interdisciplinary Studies(2023QYJC011)+4 种基金National Natural Science Foundation of China(Grant Nos.82472521,81922017)Hunan Provincial Science and Technology Department(2023JJ30896)Key Research and Development Program of Hunan Province(2022SK2023)Science and Technology Innovation Program of Hunan Province(2023RC1027)Major Basic Research Projects in Hunan Province(No.2024JC0004)。
文摘Mechanical stress modulates bone formation and organization of the extracellular matrix(ECM),the interaction of which affects heterotopic ossification(HO).However,the mechanically sensitive cell populations in HO and the underlying mechanism remain elusive.Here,we show that the mechanical protein Polysyctin-1(PC1,Pkd1)regulates CTSK lineage tendon-derived mesenchymal stem cell(TDMSC)fate and ECM organization,thus affecting HO progression.First,we revealed that CTSK lineage TDMSCs are the major source of osteoblasts and fibroblasts in HO and are responsive to mechanical cues via single-cell RNA sequencing analysis and experiments with a lineage tracing mouse model.Moreover,we showed that PC1 mediates the mechanosignal transduction of CTSK lineage TDMSCs to regulate osteogenic and fibrogenic differentiation and alters the ECM architecture by facilitating TAZ nuclear translocation.Conditional gene depletion of Pkd1 or Taz in CTSK lineage cells and pharmaceutical intervention in the PC1-TAZ axis disrupt osteogenesis,fibrogenesis and ECM organization,and consequently attenuate HO progression.These findings suggest that mechanically sensitive CTSK-lineage TDMSCs contribute to heterotopic ossification through PC1-TAZ signaling axis mediated cell fate determination and ECM organization.
基金financially supported by the National Key Research and Development Program of China(Grant No.2022YFC2806100)the National Natural Science Foundation of China(Grant Nos.U22B20126 and 52374020)+1 种基金Science Foundation of China University of Petroleum,Beijing(Grant No.2462025QNXZ009)Beijing Nova Program(Grant No.20250484913).
文摘Steel catenary riser represents the pioneering riser technology implemented in China’s deep-sea oil and gas opera-tions.Given the complex mechanical conditions of the riser,extensive research has been conducted on its dynamic analysis and structural design.This study investigates a deep-sea oil and gas field by developing a coupled model of a semi-submersible platform and steel catenary riser to analyze it mechanical behavior under extreme marine condi-tions.Through multi-objective optimization methodology,the study compares and analyzes suspension point tension and touchdown point stress under various conditions by modifying the suspension position,suspension angle,and catenary length.The optimal configuration parameters were determined:a suspension angle of 12°,suspension position in the southwest direction of the column,and a catenary length of approximately 2000 m.These findings elucidate the impact of configuration parameters on riser dynamic response and establish reasonable parameter layout ranges for adverse sea conditions,offering valuable optimization strategies for steel catenary riser deployment in domestic deep-sea oil and gas fields.
基金financially supported by the National Natural Science Foundation of China(Grant No.52222111)the Science Foundation of China University of Petroleum,Beijing(Grant No.2462025SZBH002)。
文摘This study examines the slug-induced vibration(SIV)response and fatigue behavior of offshore risers subjected to internal slug flow.A structural model incorporating internal slug flow dynamics is developed using the Absolute Nodal Coordinate Formulation(ANCF)and a spatial-temporal density variation equation to analyze how slug flow parameters affect the SIV response of risers.Structural displacement,stress,and fatigue responses are systematically evaluated to characterize the structural behavior under SIV conditions.Longer slugs induce more pronounced traveling wave characteristics,while shorter slugs facilitate a mixed traveling-standing wave mode.Moreover,higher slug frequencies lead to increased fatigue accumulation,especially over an extended touchdown zone,thereby compromising the structural integrity of the riser.The findings yield valuable insights into the dynamic interactions between slug flow and riser response.This research advances the understanding of SIV mechanisms and provides a theoretical foundation for fatigue assessment and structural optimization,contributing to the safe and efficient design of offshore risers in deepwater environments.
基金financially supported by the National Natural Science Foundation of China(Grant No.52301338)the Sichuan Science and Technology Program(Grant No.2024NSFSC0968).
文摘An experimental analysis of the slug-induced vibration(SIV)of a flexible catenary riser with an aspect ratio of 130 is reported in this work.The vibration responses and internal slug flow details at different gas-liquid ratios(Q_(g)/Q_(l))and mixture velocities(vm)are non-intrusively and simultaneously captured by high-speed cameras.Both the in-plane and out-of-plane responses of the catenary riser are excited in all considered cases.The slug flow characteristics,including translational velocities,slug lengths,recurrence frequencies,and pressure variations,are analyzed and dis-cussed,as are the dynamic responses of the riser in terms of the amplitudes,space-varying frequency,and modal weight.The dominant modal response based on the root-mean-square amplitude profiles does not match that based on the dominant frequency.Three mode switching types are identified based on the RMS amplitude profiles and the dominant frequency.When vm is small,no mode switching(NMS)is observed in either the in-plane or out-of-plane responses.For mode switching I(MS I),the switching between the first and second modes in the in-plane response is induced by slug flow with different recurrence frequencies in cases of large Q_(g)/Q_(l).However,there is no mode switching in the out-of-plane response.The switching between the first and third modes for the in-plane response and the second and fourth modes for the out-of-plane response(MS II)occurs in cases of relatively high vm and low Q_(g)/Q_(l).
基金financially supported by Sichuan Science and Technology Program(Grant No.2023NSFSC1980).
文摘This study examines the adaptive boundary control problem of flexible marine riser with internal flow coupling.The dynamic model of the flexible marine riser system with internal flow coupling is derived using the Hamiltonian principle.An analysis of internal flow’s influence on the vibration characteristics of flexible marine risers is conducted.Then,for the uncertain environmental disturbance,the adaptive fuzzy logic system is introduced to dynamically approximate the boundary disturbance,and a robust adaptive fuzzy boundary control is proposed.The uniform boundedness of the closed-loop system is proved based on Lyapunov theory.The well-posedness of the closed-loop system is proved by operator semigroup theory.The proposed control’s effectiveness is validated through comparison with existing control methods.
基金The research work was financially supported by the National Natural Science Foundation of China(Grant Nos.51979238 and 52301338)the Sichuan Science and Technology Program(Grant Nos.2023NSFSC1953 and 2023ZYD0140).
文摘Mitigating vortex-induced vibrations(VIV)in flexible risers represents a critical concern in offshore oil and gas production,considering its potential impact on operational safety and efficiency.The accurate prediction of displacement and position of VIV in flexible risers remains challenging under actual marine conditions.This study presents a data-driven model for riser displacement prediction that corresponds to field conditions.Experimental data analysis reveals that the XGBoost algorithm predicts the maximum displacement and position with superior accuracy compared with Support vector regression(SVR),considering both computational efficiency and precision.Platform displacement in the Y-direction demonstrates a significant positive correlation with both axial depth and maximum displacement magnitude.The fourth point displacement exhibits the highest contribution to model prediction outcomes,showing a positive influence on maximum displacement while negatively affecting the axial depth of maximum displacement.Platform displacement in the X-and Y-directions exhibits competitive effects on both the riser’s maximum displacement and its axial depth.Through the implementation of XGBoost algorithm and SHapley Additive exPlanation(SHAP)analysis,the model effectively estimates the riser’s maximum displacement and its precise location.This data-driven approach achieves predictions using minimal,readily available data points,enhancing its practical field applications and demonstrating clear relevance to academic and professional communities.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.U1906233 and 52201312)Dalian High-Level Talent Innovation Program(Grant No.2021RD16)the Natural Science Foundation of Liaoning Province of China(Grant No.2023-BSBA-052).
文摘The carcass layer is the innermost structure of flexible marine risers and is responsible for resisting external pressure.It has an“S”section with a spiral interlocking feature.After the multi-pass roll forming of a flat steel strip,a carcass layer is formed by lock forming.During roll forming,the steel strip undergoes significant plastic deformation,and its local area accumulates residual stress owing to multiple loading and unloading cycles.These phenomena complicate the design and analysis of the carcass layer multi-pass roll forming(CLMRF)process and cause issues in the carcass layer during manufacturing,such as strip fracture and low forming quality.Thus,herein,CLMRF was investigated to clarify the stress distribution,and a parameter analysis was performed.First,the CLMRF process was designed on the basis of classical roll-forming design theory.Second,a finite element model was established,and CLMRF was simulated.Third,the distributions of the forming stress and residual stress of the strip during CLMRF were investigated.Finally,the influences of the strip thickness,roll gap,roll distance,and angular increment were investigated.The conclusions of this study can be used to provide technical guidance in the manufacturing of flexible risers.
文摘BACKGROUND Thumb replantation following complete traumatic avulsion requires complex techniques to restore function,especially in cases of avulsion at the level of the metacarpophalangeal joint(MCP I)and avulsion of the flexor pollicis longus(FPL)at the musculotendinous junction.Possible treatments include direct tendon suture or tendon transfer,most commonly from the ring finger.To optimize function and avoid donor finger complications,we performed thumb replantation with flexion restoration using brachioradialis(BR)tendon transfer with palmaris longus(PL)tendon graft.CASE SUMMARY A 20-year-old left-handed male was admitted for a complete traumatic left thumb amputation following an accident while sliding from the top of a handrail.The patient presented with skin and bone avulsion at the MCP I,avulsion of the FPL tendon at the musculotendinous junction(zone 5),avulsion of the extensor pollicis longus tendon(zone T3),and avulsion of the thumb’s collateral arteries and nerves.The patient was treated with two stage thumb repair.The first intervention consisted of thumb replantation with MCP I arthrodesis,resection of avulsed FPL tendon and implantation of a silicone tendon prosthesis.The second intervention consisted of PL tendon graft and BR tendon transfer.Follow-up at 10 months showed good outcomes with active interphalangeal flexion of 70°,grip strength of 45 kg,key pinch strength of 15 kg and two-point discrimination threshold of 4 mm.CONCLUSION Flexion restoration after complete thumb amputation with FPL avulsion at the musculotendinous junction can be achieved using BR tendon transfer with PL tendon graft.
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financially supported by the National Natural Science Foundation of China(Grant No.52201312).
文摘As oil and gas exploration moves into deeper waters,marine risers are subjected to increasingly complex service conditions,including vessel motions,ocean currents,seabed-soil interactions,and internal flow effects.This work establishes a dynamic behavior model of steel catenary risers(SCRs)with varying curvatures subjected to internal flow and external currents and considers the effects of pipe-soil interactions on the curvature profile.The governing equation is solved via the generalized integral transform technique(GITT),which yields a semi-analytical solution of a high-order nonlinear partial differential equation.Parametric studies are then performed to analyze the effects of varying curvature on the vibration frequency and amplitude of SCRs.The vibration frequency and amplitude increase with the touchdown angle and hang-off angle,although the effect of the hang-off angle is negligible.Additionally,as the curvature increases along the centerline axis,the position of the maximum amplitude of the SCR moves upward.
基金support of the School of Engineering,Lancaster University,UK,for the Engineering Department Studentship as well as the Engineering and Physical Sciences Research Council(EPSRC)’s Doctoral Training Centre(DTC)。
文摘With the increasing exploration of oil and gas into deep waters,the necessity for material development increases for lighter conduits such as composite marine risers,in the oil and gas industry.To understand the research knowledge on this novel area,there is a need to have a bibliometric analysis on composite marine risers.A research methodology was developed whereby the data retrieval was from SCOPUS database from 1977–2023.Then,VOSviewer was used to visualize the knowledge maps.This study focuses on the progress made by conducting knowledge mapping and scientometric review on composite marine risers.This scientometric analysis on the subject shows current advances,geographical activities by countries,authorship records,collaborations,funders,affiiliations,co‑occurrences,and future research areas.It was observed that the research trends recorded the highest publication volume in the U.S.A.,but less cluster affiiliated,as it was followed by countries like the U.K.,China,Nigeria,Australia and Singapore.Also,thisfiield has more conference papers than journal papers due to the challenge of adaptability,acceptance,qualifiication,and application of composite marine risers in the marine industry.Hence,there is a need for more collaborations on composite marine risers and more funding to enhance the research trend.
基金sponsored by the National Natural Science Foundation of China(Nos.52235007,T2121004,and 52325504)the Key R&D Program of Zhejiang(No.2024SSYS0027)+1 种基金the National Key Research and Development Program of China(Nos.2024YFB4607700 and 2024YFB4607703)the China National Postdoctoral Program for Innovative Talents(No.BX20240312)。
文摘Tendon adhesion,a prevalent complication affecting over 30%of patients after a tendon injury or surgery,results in joint stiffness and impaired mobility.Although current treatments facilitate tendon repair,they are often insufficient in preventing adhesions and promoting optimal healing outcomes.To address these challenges,we developed an oriented cryostructured silk fibroin bandage(OCSFB)using the directional freeze-casting methodology.In vitro studies demonstrated that OCSFB provided a favorable microenvironment for cell viability,proliferation,and alignment,concurrently upregulating the expression of tendon-specific genes.In a rat Achilles tendon model,OCSFB significantly reduced adhesion formation and improved tendon healing.RNA-seq analysis further revealed modulation of cell adhesion molecules,substantiating its role in tissue regeneration.The integration of silk fibroin biocompatibility with a unique microstructure that facilitates cellular adhesion and proliferation renders OCSFB a promising approach for mitigating tendon adhesions and improving repair outcomes,establishing it as a robust candidate for clinical application.
文摘BACKGROUND To treat flexor pollicis longus(FPL)muscle function loss,the 4th flexor digitorum superficialis(FDS)to the FPL tendon transfer is preferred as a reconstruction method.Various complications can occur during transfer.However,median nerve neuropathy has not been reported yet.We present a case of median nerve neuropathy caused by irritation of suture knots of the 4th FDS to the FPL tendon transfer with a review of the literature.CASE SUMMARY A 52-year-old male patient presented with paresthesia along median nerve distribution of right hand after tendon transfer.He complained of right thumb flexion limitation due to FPL function loss so authors performed the 4th FDS to FPL transfer using Pulvertaft weave technique.FPL function loss was due to adhesion resulting from repeated surgery of radius shaft.He had a history of radius shaft open fracture 9 years ago and nonunion 7 years ago.During surgery,FPL muscle was severely adhered and indistinguishable.However,tendon continuity remained intact.After tendon transfer,he experienced paresthesia along median nerve distribution upon movement of thumb.He was diagnosed with median nerve neuropathy caused by irritation of tendon suture knots.Exploration was then performed.The median nerve was irritated by suture knots of transferred tendon.Thus,knots were removed.Twelve months later,he demonstrated thumb flexion of 80°.Additionally,median nerve neuropathy symptoms fully resolved.CONCLUSION Median nerve neuropathy can occur after tendon transfer from irritation of suture knots.Covering knots using surrounding tissue is recommended.
文摘This article offers additional clinical and biomechanical insights into using the peroneus longus tendon(PLT)autograft in posterior cruciate ligament recon-struction.While recent studies report favorable knee outcomes,concerns remain regarding donor site morbidity.The PLT plays a key role in foot biomechanics,and its harvesting may lead to subtle changes,as suggested by imaging and pe-dobarographic studies.Tendon regeneration may limit long-term morbidity,but further studies are needed.We recommend that future research include gait analysis,long-term follow-up,and insights from anterior cruciate ligament li-terature.
