This paper presents an experimental analysis of a solar-assisted powered underfloor heating system,designed primarily to boost energy efficiency and achieve reliable desired steady-state temperature in buildings.We th...This paper presents an experimental analysis of a solar-assisted powered underfloor heating system,designed primarily to boost energy efficiency and achieve reliable desired steady-state temperature in buildings.We thoroughly tested the system’s thermal and operational features by subjecting it to three distinct scenarios that mimicked diverse solar irradiance and environmental conditions.Our findings reveal a strong correlation between variations in solar input and overall system performance.The Solar Fraction(SF),our key energy efficiency metric,varied significantly across the cases,ranging from 63.1%up to 88.7%.This high reliance on renewables resulted in a substantial reduction in backup power;consequently,the auxiliary electric heater was only required to supply between 1.82 and 3.00 kWh over the test periods.The circulation pump operated on a precise control logic,engaging below 20℃ and disengaging at 21℃.Crucially,the experiments verified the system’s ability not only tomeet the air temperature setpoint but also to ensure the floor surface temperature stayed within required international comfort criteria.These robust results directly support the study’s main objective.For practical application,we advise increasing the total length of the embedded pipe network.This crucial adjustment would allow for a reduction in the required circulating water temperature,which in turn maximizes the utilization of low-grade solar heat and optimizes radiant heat delivery toward achieving the desired steady-state temperature.Ultimately,the study confirms that solar-assisted underfloor heating offers a technically viable,sustainable,and energy-efficient solution with the potential to significantly cut fossil fuel consumption.展开更多
Water inrush hazards from the floor strata of longwall workingface are commonly encountered in North China coalfields,which essentially result from the evolution of permeability in the floor rock under complex mining-...Water inrush hazards from the floor strata of longwall workingface are commonly encountered in North China coalfields,which essentially result from the evolution of permeability in the floor rock under complex mining-induced stress conditions.Current research rarely addresses the evolution of rock permeability under such complex stress paths.Describing this evolution using only one stress parameter,such as effective stress,deviatoric stress,axial stress,or confining stress,is highly challenging.In this study,we developed a laboratory loading scheme that simulates mining-induced stress evolution.Hydro-mechanical experiments were conducted to investigate the evolution of rock permeability under mining stress.The mechanism on the change of stress-permeability relationships in mining-disturbed rock is revealed,supporting to the analysis of management strategies for floor water-inrush disasters.The results show that rock permeability evolves through four stages,including rapid decline,gradual fluctuation,sharp increase,and slow attenuation.1–2 permeability surges occurred during mining-stress loading,closely linked to the emergence and reversal of deviatoric stress in magnitude and direction.With the first permeability surge,the deviatoric stress within the mudstone reached approximately 1.7 MPa,whereas that of the sandstone was about 1 MPa.The second permeability surge in the mudstone corresponded to the secondary rotation of the principal stress direction.CT and ultrasonic tests suggested an increase in microcracks in both rocks during the first permeability surge.However,the deviatoric stress-permeability plot before and after mining indicated that the fracture of mudstone sample changed significantly,while that of the sandstone remained unchanged.The permeability surges observed at different stages are interpreted as resulting from shear-induced reopening of pre-existing fractures and the formation of new shear-failure fractures.A stress-permeability model jointly governed by effective mean stress and deviatoric stress was established.Furthermore,two strategies are proposed for the floor water-inrush disasters prevention,(i)timely backfilling to reduce deviatoric stress,(ii)grouting after the first permeability surge.This work provides insights into stress-seepage behavior in rocks under complex stress evolution and offers new perspectives for identifying potential water inrush pathways in the floor strata of coal seam during longwall mining.展开更多
Objectives:Postmenopausal women with stress urinary incontinence(SUI)exhibit low androgen expression.This study aimed to evaluate the efficacy and safety of vaginal androgen combined with pelvic floor muscle training(...Objectives:Postmenopausal women with stress urinary incontinence(SUI)exhibit low androgen expression.This study aimed to evaluate the efficacy and safety of vaginal androgen combined with pelvic floor muscle training(PFMT)in the treatment of SUI in postmenopausal women.Methods:Postmenopausal women with SUI were recruited from Hainan West Central Hospital between January 2024 and March 2025.Participants were randomly assigned in a double-blind manner to receive either vaginal androgen cream combined with PFMT(treatment group)or a visually identical placebo cream(without androgens)combined with PFMT(control group).The vaginal cream was applied to the vaginal wall at a dose of 0.5 g per application,twice weekly for a total of 10 applications,while PFMT was conducted for 8 weeks.The clinical efficacy and safety were compared between the two groups.Results:A total of 61 patients were finally enrolled,with 31 in the treatment group and 30 in the control group.At both 3-month and 6-month follow-ups,the treatment group demonstrated significantly lower values in daily pad usage(p<0.05),24-h pad test scores(p<0.05),and ICIQ-UI SF scores(p<0.05)compared to the control group.The improvement rate of urinary incontinence was significantly higher in the treatment group(p<0.05).Compared to baseline,the treatment group showed statistically significant reductions in all three outcome measures(all p<0.05).No severe adverse events were reported in either group during the treatment period.Conclusions:Androgen therapy combined with PFMT significantly improved the urinary incontinence remission rate in postmenopausal women with SUI,with no severe adverse effects observed.These findings suggest that androgen therapy may represent a novel therapeutic approach for SUI management in postmenopausal women.展开更多
Vaginal delivery is a fascinating physiological process,but also a high-risk process.Up to 85%–90%of vaginal deliveries lead to perineal trauma,with nearly 11%of severe perineal tearing.It is a common occurrence,espe...Vaginal delivery is a fascinating physiological process,but also a high-risk process.Up to 85%–90%of vaginal deliveries lead to perineal trauma,with nearly 11%of severe perineal tearing.It is a common occurrence,especially for first-time mothers.Computational childbirth plays an essential role in the prediction and prevention of these traumas,but fast personalization of the pelvis and floor muscles is challenging due to their anatomical complexity.This study introduces a novel shape-prediction-based personalization of the pelvis and floor muscles for perineal tearing management and childbirth simulation.300 subjects were selected from public Computed Tomography(CT)databases.The pelvic bone nmjmeshes were generated using a coarse-to-fine non-rigid mesh alignment procedure.The floor muscle meshes were personalized using the bone mesh deformation information.A feature-to-pelvic structure reconstruction pipeline was proposed,incorporating various strategies.Ten-fold cross-validation helped determine the optimal reconstruction strategy,regression method,and feature sizes.The mesh-to-mesh distance metric was employed for evaluating.The statistical shape relation-based strategy,coupled with multi-output ridge regression,was the optimal approach for pelvic structure reconstruction.With a feature set ranging from 3 to 38,the mean errors were 2.672 to 1.613 mm,and 3.237 to 1.415 mm in muscle attachment regions.The best-and worst-case predictions had errors of 1.227±0.959 mm and 2.900±2.309 mm,respectively.This study provides a novel approach to achieving fast personalized childbirth modeling and simulation for perineal tearing management.展开更多
Objective:Stress urinary incontinence(SUI)is a common condition among women that severely impairs quality of life.Pelvic floor proprioceptive training(PFPT)has attracted increasing attention for its potential to enhan...Objective:Stress urinary incontinence(SUI)is a common condition among women that severely impairs quality of life.Pelvic floor proprioceptive training(PFPT)has attracted increasing attention for its potential to enhance pelvic floor muscle function and alleviate SUI symptoms.This study aims to observe and compare the clinical efficacy of PFPT combined with electroacupuncture,electrical stimulation,and biofeedback therapy versus conventional therapy consisting of electroacupuncture,electrical stimulation,and biofeedback alone in women with SUI,and to explore the role of PFPT in improving symptom and functional outcomes.Methods:In this randomized controlled trial,72 women with mild to moderate SUI were recruited from the Department of Rehabilitation Medicine at Third Xiangya Hospital,Central South University,between December 2021 and October 2023.Participants were randomly assigned to an experimental group(n=36)or a control group(n=36).Both groups received health education.The control group underwent electroacupuncture combined with electrical stimulation and biofeedback therapy,while the experimental group additionally received PFPT 3 times per week for 4 weeks.The primary outcome was assessed using the International Consultation on Incontinence Questionnaire-Short Form(ICIQ-SF).Secondary outcomes included pelvic floor muscle strength,bladder neck mobility,and balance ability.The ICIQ-SF was reassessed at 1,3,6,and 12 months post-treatment.Results:Both groups showed statistically significant improvements in all parameters after treatment(all P<0.05).However,there were no statistically significant differences between groups in most measures(all P>0.05).The experimental group demonstrated longer singleleg stance duration with eyes closed than the control group(left leg:P=0.026;right leg:P=0.006),with a significant increase from baseline(P<0.001).At 6 months post-treatment,the cure rate in the experimental group was significantly higher than that in the control group(P=0.037).Conclusion:Conventional therapy effectively improves SUI symptoms,but adding PFPT provides notable additional benefits,including enhanced balance ability and sustained midterm cure rates.These findings suggest that PFPT is a valuable adjunct to standard SUI management strategies.展开更多
The seismic design forces of nonstructural components(NSCs)in buildings are closely related to floor acceleration response amplification.To investigate the differences in acceleration responses of structures with diff...The seismic design forces of nonstructural components(NSCs)in buildings are closely related to floor acceleration response amplification.To investigate the differences in acceleration responses of structures with different structural types,fundamental periods,and seismic design levels,56 reinforced concrete and steel structures with fundamental periods ranging from 0.37 s to 5.68 s were selected.For each structure,100 sets of earthquake motions were used as inputs for elastic time history analysis.Based on the resulting 26,500 sets of floor acceleration response data,the amplification rules of peak floor acceleration/peak ground acceleration(PFA/PGA)along the height of various structures and the corresponding floor response spectrum characteristics were studied.The nonlinear changes of PFA/PGA along the height of long period structures were compared with the codes of different countries.Moreover,more suitable prediction equations were proposed based on the structural characteristics.Finally,to solve the issue that existing research still cannot accurately reflect the acceleration amplification coefficient of NSCs with different dynamic characteristics in main structures with different periods,a normalized floor response spectrum is proposed that can simultaneously consider the effects of input ground motion characteristics and the main structure,which can be better used in the seismic design of NSCs.展开更多
In this editorial,we comment on an article by Wang et al.Recent literature shows an increase in research on pelvic organ prolapse(POP).Although the true incidence of POP remains uncertain,its impact on quality of life...In this editorial,we comment on an article by Wang et al.Recent literature shows an increase in research on pelvic organ prolapse(POP).Although the true incidence of POP remains uncertain,its impact on quality of life is substantial.Anatomical studies report high incidence rates,surpassing those observed in symptom-based surveys.Weakness of the endopelvic fascia is a primary anatomical risk factor for POP.Additionally,gestational diabetes mellitus(GDM)has emerged as a growing concern,as poor glycemic control increases complications for both mother and fetus.GDM and POP are interconnected,with factors like maternal obesity,macrosomia,and hormonal changes exacerbating pelvic floor dysfunction.Modifiable risk factors,such as obesity and chronic hyperglycemia,along with multiparity,instrumental deliveries,and obstetric trauma,further increase susceptibility.For patients with GDM,gynecological exams,Pelvic Organ Prolapse Quantification staging,and pelvic floor ultrasonography are valuable diagnostics,with proctological exams and magnetic resonance defecography aiding in multi-compartment prolapse diagnoses.Imaging,though uncomfortable during pregnancy,is safe in the early postpartum period.This editorial emphasizes the need for further research on the pathophysiology of GDM-related POP and offers recommendations for improving diagnosis and clinical management of patients with GDM.展开更多
With the depletion of shallow mineral resources,mining operations are extending to greater depths and larger scales,increasing the risk of water inrush disasters,particularly from confined aquifers intersected by faul...With the depletion of shallow mineral resources,mining operations are extending to greater depths and larger scales,increasing the risk of water inrush disasters,particularly from confined aquifers intersected by faults.This paper reviews the current state of research on fault-induced water inrushes in mining faces,examining the damage characteristics and permeability of fractured floor rock,the mechanical behavior of faults under mining stress,and the mechanisms driving water inrush.Advances in prevention technologies,risk assessment,and prediction methods are also summarized.Research shows that damage evolution in fractured floor rock,coupled with fluid-solid interactions,provides the primary pathways for water inrush.Stress-seepage coupling in porous media plays a decisive role in determining inrush potential.Mining-induced stress redistribution can activate faults,with parameters such as dip angle and internal friction angle controlling stress evolution and slip.Critical triggers include the hydraulic connectivity among faults,aquifers,and mining-induced fracture networks,followed by hydraulic erosion.A multi-pronged prevention framework has been developed,integrating precise fault detection,targeted grouting for water sealing,drainage to reduce water pressure,optimized waterproof coal pillar design,and dynamic risk assessment and prediction.However,gaps remain in understanding multi-physical field coupling under deep mining conditions,establishing quantitative criteria for fault activation-induced water inrush,and refining control technologies.Future work should focus on multi-scale numerical simulations,advanced active control measures,and intelligent,integrated prevention systems to clarify the mechanisms of fault-induced water inrush and enhance theoretical and technical support for mine safety.展开更多
Objective:Pelvic floor dysfunction is common among pregnant and postpartum women and significantly impacts quality of life.This study aims to translate the German Pelvic Floor Questionnaire for Pregnant and Postpartum...Objective:Pelvic floor dysfunction is common among pregnant and postpartum women and significantly impacts quality of life.This study aims to translate the German Pelvic Floor Questionnaire for Pregnant and Postpartum Women into Chinese and to evaluate its reliability and validity in the Chinese population.Methods:The questionnaire was translated using the Brislin model.A cross-sectional study was conducted among pregnant and postpartum women to assess the content validity,construct validity,Cronbach’sαcoefficient,test-retest reliability,and split-half reliability of the Chinese version.Results:A total of 72 women were included,with 6.9% being pregnant and 93.1% postpartum;the age was(32.3±3.6)years.The Chinese version of the questionnaire contains 4 dimensions and 45 items.The content validity index of individual items ranged from 0.833 to 1.000,with a scale-level content validity index of 0.977 and intraclass correlation coefficients(ICCs)exceeding 0.90.The overall Cronbach’s α coefficient was 0.891,with subscale coefficients ranging from 0.732 to 0.884(all ICCs>0.70).The testretest reliability of the total scale was 0.833,and for the 4 dimensions,bladder,bowel,prolapse,and sexual function,the values were 0.776,0.579,0.732,and 0.645,respectively.The split-half reliability was 0.74.Conclusion:The Chinese version of the questionnaire demonstrated good reliability and validity,indicating its applicability in assessing pelvic floor dysfunction and associated risk factors during pregnancy and postpartum.展开更多
Conversation A(in a department store)Sara:Department store directories are helpful.Sam:They are.Today,I have to buy new furniture and bedding for my apartment.They're on the sixth floor.
BACKGROUND Postpartum women are at an increased risk of generalized anxiety disorder(GAD),which can negatively affect both mental health and physical recovery.Pelvic floor dysfunction,common in this population,can exa...BACKGROUND Postpartum women are at an increased risk of generalized anxiety disorder(GAD),which can negatively affect both mental health and physical recovery.Pelvic floor dysfunction,common in this population,can exacerbate psychological distress.Although pelvic floor rehabilitation is effective in physical recovery,its potential to improve psychological outcomes,especially in women with GAD,remains underexplored.AIM To evaluate the effectiveness of an individualized pelvic floor rehabilitation program in improving anxiety,pelvic floor function,and quality of life in postpartum women with GAD.METHODS A retrospective study was performed to analyze 80 postpartum women with GAD who completed a 12-week individualized pelvic floor rehabilitation program(January 2020-December 2024),combining supervised pelvic floor muscle training and psychological support.Primary outcomes were changes in GAD-7 and Hamilton anxiety rating scale(HAM-A)scores and pelvic floor function measured by surface electromyography(sEMG).Secondary outcomes included World Health Organization quality of life-BREF,pelvic floor symptom severity,and impact on daily activities(pelvic floor impact questionnaire).Assessments were conducted at baseline and 6 and 12 weeks during the intervention period.RESULTS Significant improvements were observed in anxiety measures,with mean GAD-7 scores decreasing from 14.8±3.2 at baseline to 8.2±2.9 at week 12(P<0.001)and HAM-A scores decreasing from 22.6±4.5 to 12.4±3.8(P<0.001).Pelvic floor function showed substantial enhancement,with sEMG amplitude increasing from 22.4±5.6μV to 35.9±6.8μV(P<0.001).Quality of life improved across all domains,with the most significant improvements in psychological(28.5%increase)and physical health(25.8%increase).Program adherence was 91.5%for the supervised sessions,and no serious adverse events were reported.CONCLUSION Individualized pelvic floor rehabilitation training effectively improves both psychological and functional outcomes in postpartum women with GAD.The high adherence and significant outcomes make this integrated approach feasible and effective.展开更多
Pelvic floor dysfunction(PFD),including conditions such as stress urinary incontinence,pelvic organ prolapse,and fecal incontinence,significantly affects women's quality of life and their physical and mental healt...Pelvic floor dysfunction(PFD),including conditions such as stress urinary incontinence,pelvic organ prolapse,and fecal incontinence,significantly affects women's quality of life and their physical and mental health.With advancement of digital medicine,the systematic collection of data and the high-quality development of database platforms have increasingly become central pillars of PFD research and management.We systematically review the developmental stages of PFDrelated databases.We then conduct a comparative analysis of representative international and domestic platforms,examining key aspects including organizational structures and construction models,data sources and integration strategies,core functionalities,data quality control and standardization,data security and access management,and research applications.Finally,based on the current status of PFD database development both globally and in China,we offer recommendations to strengthen data infrastructure and guide future directions.The findings may serve as a valuable reference for the optimization of PFD databases worldwide.展开更多
The duration of snow cover has shortened in the boreal region,and the amount of seasonal snow decreased.This affects the coupling between soil and air temperatures and may thus lead to colder soil and deeper soil fros...The duration of snow cover has shortened in the boreal region,and the amount of seasonal snow decreased.This affects the coupling between soil and air temperatures and may thus lead to colder soil and deeper soil frost.We prevented snow reaching the forest floor for two winters in mature boreal forest and studied how that affects tree and forest floor processes.The studied species were Scots pine,Norway spruce,silver birch,and a dwarf shrub bilberry.Decreased soil temperature,due to the lack of snow cover,decreased forest floor respiration in winter and spring.Simultaneously,response of respiration to temperature seemed to increase,perhaps due to the exposure of forest floor vegetation to cold air temperature.Indeed,lack of snow cover induced mortality of bilberry,but the remaining ramets grew more in height and their average leaf size was larger likely to compensate for the lost plant biomass.Lack of snow cover also affected tree hydraulics as tree water uptake was decreased in spring,and the start of the sap season delayed in birch.Pine and birch tended to grow less in the snow exclusion treatment(differences not statistically significant),whereas spruce grew more.Coarse root traits,e.g.water content and cellular frost damages,were not affected by the snow exclusion treatment.The results of this case study increase our understanding on the effects of changing snow cover on spring-time tree and forest floor processes in mature boreal forest,but also reveal the need for further studies on mature trees.展开更多
Floor heave is a common water-induced issue of loess tunnels.However,the mechanism of tunnel floor heave induced by repeated rainfall or irrigation remains poorly understood.This study analyzes moisture variation at t...Floor heave is a common water-induced issue of loess tunnels.However,the mechanism of tunnel floor heave induced by repeated rainfall or irrigation remains poorly understood.This study analyzes moisture variation at the tunnel base and invert deformation through a 15-year survey of an operational loess tunnel.An improved Green-Ampt model was developed to capture the effects of interannual repeated infiltration on water content,permeability,and matric suction at the tunnel base.The model was validated using soil column infiltration tests.The calculated wetting front depth was incorporated into the tunnel numerical simulation to analyze the development of floor heave and assess its several influencing factors.Results show the base average water content at the tunnel base increases exponentially with operational years.After 15 years,over 50%of the monitored sections reach saturation,leading to significant invert uplift.Based on the plastic limit,saturation water content,and liquid limit of loess,floor heave is categorized into four levels with deformation thresholds at 10,25,and 50 mm.The modified Green-Ampt model is suitable for repeated infiltration conditions and offers practical guidance.Neglecting hydraulic deterioration due to repeated infiltration may lead to significant prediction errors.Numerical simulations reveal that the inverted arch uplift height,width,and height-to-width ratio increase linearly with the rise in the number of infiltration events.The uplift deformation follows Gaussian distribution in both cross and longitudinal sections,forming aΛ-shaped floor heave.The influence of infiltration duration,water content,horizontal infiltration,asymmetric infiltration,burial depth,and the number of infiltration events enhanced successively on floor heave.This model facilitates the prediction of floor heave under dynamic hydrological conditions during long-term tunnel operation.展开更多
The shop floor dynamic scheduling system based on human-computer interaction is the use of computer-aided decision-making and human-computer interaction to solve the dynamic scheduling problem.A human-computer interac...The shop floor dynamic scheduling system based on human-computer interaction is the use of computer-aided decision-making and human-computer interaction to solve the dynamic scheduling problem.A human-computer interaction interface based on Gantt chart is designed,which can not only comprehensively and quantitatively represent the scheduling process and scheduling scheme,but also have friendly human-computer interaction performance.The data transmission and interaction architecture is constructed to realize the rapid response to shop floor disturbance events.A priority calculation algorithm integrating priority rules and dispatcher preference is proposed,which realizes the automatic calculation of priority for the dispatcher's reference and reduces theirburden.A man-machine interactive shop floor dynamic scheduling strategy is proposed.When solving the dynamic flexible job shop scheduling problem caused by machine tool breakdown and urgent order,the origin moments obtained by using this strategy are 0.4190 and 0.3703 respectively.As can be seen from the origin moment indicator,the dynamic shop floor scheduling system based on the human-computer interaction is efficient and reliable in solving dynamic scheduling problems,and related strategies of this system are also feasible and stable.展开更多
Floor heave is a common defect in mountainous tunnels.It is critical but challenging to predict the risk of floor heave,as traditional methods often fail to characterize this phenomenon effectively.This study proposes...Floor heave is a common defect in mountainous tunnels.It is critical but challenging to predict the risk of floor heave,as traditional methods often fail to characterize this phenomenon effectively.This study proposes a data-driven approach utilizing a support vector machine(SVM)optimized by the sparrow search algorithm(SSA)to address the issue.The model was developed and validated using a dataset collected from 100 tunnels.Shapley value analysis was conducted to identify the key features influencing floor heave defects.Moreover,a committee-based uncertainty quantification method is presented to evaluate the reliability of each prediction.The results show that:(1)Data feature engineering and SSA play pivotal roles in expediting the convergence of the SVM model.(2)Groundwater and high in situ stress are key factors contributing to tunnel floor heave.(3)In comparison to backpropagation(BP)neural networks,the SSA-SVM demonstrates superior robustness in handling imperfect and limited data.(4)The committee-based uncertainty quantification method is proven effective to evaluate the trustworthiness of each prediction.This data-driven surrogate model offers an effective strategy for understanding the factors that impact tunnel floor defects and accurately predicting tunnel floor heave deformation.展开更多
This paper presents a comprehensive experimental and numerical investigation of radiant floor heating(RFH)systems integrated with phase changematerial(PCM)-based thermal energy storage(TES).The study compares two unde...This paper presents a comprehensive experimental and numerical investigation of radiant floor heating(RFH)systems integrated with phase changematerial(PCM)-based thermal energy storage(TES).The study compares two underfloor pipe configurations:double serpentine and spiral.It also looks at how well a paraffin wax PCM system works with compact heat exchanger-type TES units during winter in Iraq.Key performance indicators including discharge temperature,heat transfer rate,liquid fraction evolution,and temperature uniformity were assessed through in situ experimental measurements and ANSYS fluent simulations.Results demonstrate that the spiral design provides slightly more uniform temperature distribution on the tile surface at an inlet water temperature of 55℃,with an average difference of approximately 0.5%,the serpentine layout exhibits higher slab temperature distribution by about 0.66%.Notably,the serpentine configuration shows superior thermal homogeneity and heat distribution,with a 15.05%increase in heat gain at a 55℃ inlet temperature compared to the spiral design.The performance gap between the two layouts narrows as the inlet temperature increases from 50℃ in 5℃ increments by approximately 4.1%,3.7%,and 1.7%,respectively.Higher inlet temperatures also improve PCM discharging and charging rates,improving energy storage utilization.The findings provide significant design guidelines for sustainable heating systems for cold climates.展开更多
Gateways at faces of great mining heights are mostly driven along the roof of coal seams.For gateway height restrictions,a 1-3 m floor coal is retained,leaving a triangular floor coal at the face ends,causing a loss o...Gateways at faces of great mining heights are mostly driven along the roof of coal seams.For gateway height restrictions,a 1-3 m floor coal is retained,leaving a triangular floor coal at the face ends,causing a loss of coal.In order to improve coal recovery rates and to ensure efficiency of equipment at coal mining faces,we investigated suitable retention methods and recovery technology of floor coal at face ends.The upper floor coal can directly be recovered by a shearer with floor dinting.The lower floor coal is recovered by shearer with floor dinting after advanced floor dinting and retaining a step for protecting coal sides in a haulage gateway.Field practice shows that this method can improve the coal recovery rates at fully mechanized working faces with great mining heights.展开更多
To evaluate the thermal performance of a low-temperature electrical radiant floor heating system,an experimental facility equipped with a constant temperature chamber and different specimen floors is designed and buil...To evaluate the thermal performance of a low-temperature electrical radiant floor heating system,an experimental facility equipped with a constant temperature chamber and different specimen floors is designed and built.The heating cable is installed in the floor slab with a unit-rated power of 30 W/m.Twenty-four different schemes are worked out and tested,which include three kinds of composite floor structures and eight kinds of cable distances.The cable distances are 30,40,50,60,80,100,130,150 mm.The main affective factors of the thermal performance and their influencing regularity are discussed.The experimental results show that the system has good stability and reliability,and the ratio of the radiation heat-transfer rate to the gross heat-transfer rate is greater than 50%.When the floor structure and the cable distance are fixed,the gross heat-transfer rate of the upper floor surface has a maximum value at an optimal cable distance.Under the experimental conditions in this paper,the optimal cable distance is 50 mm.展开更多
Estimating the overall floor stability in a coal mine using deterministic methods which require complex engineering properties of floor strata is desirable,but generally it is impractical due to the difficulty of gath...Estimating the overall floor stability in a coal mine using deterministic methods which require complex engineering properties of floor strata is desirable,but generally it is impractical due to the difficulty of gathering essential input data.However,applying a quantitative methodology to describe floor quality with a single number provides a practical estimate for preliminary assessment of floor stability.The coal mine floor rating(CMFR)system,developed by the University of New South Wales(UNSW),is a rockmass classification system that provides an indicator for the competence of floor strata.The most significant components of the CMFR are uniaxial compressive strength and discontinuity intensity of floor strata.In addition to the competence of the floor,depth of cover and stress notch angle are input parameters used to assess the preliminary floor stability.In this study,CMFR methodology was applied to a Central Appalachian Coal Mine that intermittently experienced floor heave.Exploratory drill core data,overburden maps,and mine plans were utilized for the study.Additionally,qualitative data(failure/non-failure)on floor conditions of the mine entries near the core holes was collected and analyzed so that the floor quality and its relation to entry stability could be estimated by statistical methods.It was found that the current CMFR classification system is not directly applicable in assessing the floor stability of the Central Appalachian Coal Mine.In order to extend the applicability of the CMFR classification system,the methodology was modified.A calculation procedure of one of the CMFR classification system’s components,the horizontal stress rating(HSR),was changed and new parameters were added to the HSR.展开更多
文摘This paper presents an experimental analysis of a solar-assisted powered underfloor heating system,designed primarily to boost energy efficiency and achieve reliable desired steady-state temperature in buildings.We thoroughly tested the system’s thermal and operational features by subjecting it to three distinct scenarios that mimicked diverse solar irradiance and environmental conditions.Our findings reveal a strong correlation between variations in solar input and overall system performance.The Solar Fraction(SF),our key energy efficiency metric,varied significantly across the cases,ranging from 63.1%up to 88.7%.This high reliance on renewables resulted in a substantial reduction in backup power;consequently,the auxiliary electric heater was only required to supply between 1.82 and 3.00 kWh over the test periods.The circulation pump operated on a precise control logic,engaging below 20℃ and disengaging at 21℃.Crucially,the experiments verified the system’s ability not only tomeet the air temperature setpoint but also to ensure the floor surface temperature stayed within required international comfort criteria.These robust results directly support the study’s main objective.For practical application,we advise increasing the total length of the embedded pipe network.This crucial adjustment would allow for a reduction in the required circulating water temperature,which in turn maximizes the utilization of low-grade solar heat and optimizes radiant heat delivery toward achieving the desired steady-state temperature.Ultimately,the study confirms that solar-assisted underfloor heating offers a technically viable,sustainable,and energy-efficient solution with the potential to significantly cut fossil fuel consumption.
基金supported by the National Natural Science Foundation of China(Nos.U22A20165 and 52474156)the Key Research and Development Program of Xinjiang Uyghur Autonomous Region(No.2023B01010-1)the China Scholarship Council(No.202406420054).
文摘Water inrush hazards from the floor strata of longwall workingface are commonly encountered in North China coalfields,which essentially result from the evolution of permeability in the floor rock under complex mining-induced stress conditions.Current research rarely addresses the evolution of rock permeability under such complex stress paths.Describing this evolution using only one stress parameter,such as effective stress,deviatoric stress,axial stress,or confining stress,is highly challenging.In this study,we developed a laboratory loading scheme that simulates mining-induced stress evolution.Hydro-mechanical experiments were conducted to investigate the evolution of rock permeability under mining stress.The mechanism on the change of stress-permeability relationships in mining-disturbed rock is revealed,supporting to the analysis of management strategies for floor water-inrush disasters.The results show that rock permeability evolves through four stages,including rapid decline,gradual fluctuation,sharp increase,and slow attenuation.1–2 permeability surges occurred during mining-stress loading,closely linked to the emergence and reversal of deviatoric stress in magnitude and direction.With the first permeability surge,the deviatoric stress within the mudstone reached approximately 1.7 MPa,whereas that of the sandstone was about 1 MPa.The second permeability surge in the mudstone corresponded to the secondary rotation of the principal stress direction.CT and ultrasonic tests suggested an increase in microcracks in both rocks during the first permeability surge.However,the deviatoric stress-permeability plot before and after mining indicated that the fracture of mudstone sample changed significantly,while that of the sandstone remained unchanged.The permeability surges observed at different stages are interpreted as resulting from shear-induced reopening of pre-existing fractures and the formation of new shear-failure fractures.A stress-permeability model jointly governed by effective mean stress and deviatoric stress was established.Furthermore,two strategies are proposed for the floor water-inrush disasters prevention,(i)timely backfilling to reduce deviatoric stress,(ii)grouting after the first permeability surge.This work provides insights into stress-seepage behavior in rocks under complex stress evolution and offers new perspectives for identifying potential water inrush pathways in the floor strata of coal seam during longwall mining.
基金supported by Joint Program on Health Science&Technology Innovation of Hainan Province(WSJK2024QN093)Discipline Leader Development Program for Outstanding Talents of Hainan West Central Hospital.
文摘Objectives:Postmenopausal women with stress urinary incontinence(SUI)exhibit low androgen expression.This study aimed to evaluate the efficacy and safety of vaginal androgen combined with pelvic floor muscle training(PFMT)in the treatment of SUI in postmenopausal women.Methods:Postmenopausal women with SUI were recruited from Hainan West Central Hospital between January 2024 and March 2025.Participants were randomly assigned in a double-blind manner to receive either vaginal androgen cream combined with PFMT(treatment group)or a visually identical placebo cream(without androgens)combined with PFMT(control group).The vaginal cream was applied to the vaginal wall at a dose of 0.5 g per application,twice weekly for a total of 10 applications,while PFMT was conducted for 8 weeks.The clinical efficacy and safety were compared between the two groups.Results:A total of 61 patients were finally enrolled,with 31 in the treatment group and 30 in the control group.At both 3-month and 6-month follow-ups,the treatment group demonstrated significantly lower values in daily pad usage(p<0.05),24-h pad test scores(p<0.05),and ICIQ-UI SF scores(p<0.05)compared to the control group.The improvement rate of urinary incontinence was significantly higher in the treatment group(p<0.05).Compared to baseline,the treatment group showed statistically significant reductions in all three outcome measures(all p<0.05).No severe adverse events were reported in either group during the treatment period.Conclusions:Androgen therapy combined with PFMT significantly improved the urinary incontinence remission rate in postmenopausal women with SUI,with no severe adverse effects observed.These findings suggest that androgen therapy may represent a novel therapeutic approach for SUI management in postmenopausal women.
基金funded by Vietnam National University Ho Chi Minh City(VNU-HCM)under grant number DS.C2025-28-06.
文摘Vaginal delivery is a fascinating physiological process,but also a high-risk process.Up to 85%–90%of vaginal deliveries lead to perineal trauma,with nearly 11%of severe perineal tearing.It is a common occurrence,especially for first-time mothers.Computational childbirth plays an essential role in the prediction and prevention of these traumas,but fast personalization of the pelvis and floor muscles is challenging due to their anatomical complexity.This study introduces a novel shape-prediction-based personalization of the pelvis and floor muscles for perineal tearing management and childbirth simulation.300 subjects were selected from public Computed Tomography(CT)databases.The pelvic bone nmjmeshes were generated using a coarse-to-fine non-rigid mesh alignment procedure.The floor muscle meshes were personalized using the bone mesh deformation information.A feature-to-pelvic structure reconstruction pipeline was proposed,incorporating various strategies.Ten-fold cross-validation helped determine the optimal reconstruction strategy,regression method,and feature sizes.The mesh-to-mesh distance metric was employed for evaluating.The statistical shape relation-based strategy,coupled with multi-output ridge regression,was the optimal approach for pelvic structure reconstruction.With a feature set ranging from 3 to 38,the mean errors were 2.672 to 1.613 mm,and 3.237 to 1.415 mm in muscle attachment regions.The best-and worst-case predictions had errors of 1.227±0.959 mm and 2.900±2.309 mm,respectively.This study provides a novel approach to achieving fast personalized childbirth modeling and simulation for perineal tearing management.
基金supported by the Natural Science Foundation of Hunan Province(2024JJ8121,2024JJ6626)the Hunan Provincial Key Research and Development Program(2023SK2038),China.
文摘Objective:Stress urinary incontinence(SUI)is a common condition among women that severely impairs quality of life.Pelvic floor proprioceptive training(PFPT)has attracted increasing attention for its potential to enhance pelvic floor muscle function and alleviate SUI symptoms.This study aims to observe and compare the clinical efficacy of PFPT combined with electroacupuncture,electrical stimulation,and biofeedback therapy versus conventional therapy consisting of electroacupuncture,electrical stimulation,and biofeedback alone in women with SUI,and to explore the role of PFPT in improving symptom and functional outcomes.Methods:In this randomized controlled trial,72 women with mild to moderate SUI were recruited from the Department of Rehabilitation Medicine at Third Xiangya Hospital,Central South University,between December 2021 and October 2023.Participants were randomly assigned to an experimental group(n=36)or a control group(n=36).Both groups received health education.The control group underwent electroacupuncture combined with electrical stimulation and biofeedback therapy,while the experimental group additionally received PFPT 3 times per week for 4 weeks.The primary outcome was assessed using the International Consultation on Incontinence Questionnaire-Short Form(ICIQ-SF).Secondary outcomes included pelvic floor muscle strength,bladder neck mobility,and balance ability.The ICIQ-SF was reassessed at 1,3,6,and 12 months post-treatment.Results:Both groups showed statistically significant improvements in all parameters after treatment(all P<0.05).However,there were no statistically significant differences between groups in most measures(all P>0.05).The experimental group demonstrated longer singleleg stance duration with eyes closed than the control group(left leg:P=0.026;right leg:P=0.006),with a significant increase from baseline(P<0.001).At 6 months post-treatment,the cure rate in the experimental group was significantly higher than that in the control group(P=0.037).Conclusion:Conventional therapy effectively improves SUI symptoms,but adding PFPT provides notable additional benefits,including enhanced balance ability and sustained midterm cure rates.These findings suggest that PFPT is a valuable adjunct to standard SUI management strategies.
基金Natural Science Foundation of China under Grant Nos.52078471,52078472 and 52208509National Key Research and Development Plan of China under Grant No.2019YFE0112700+2 种基金Natural Science Foundation of Heilongjiang Province under Grant No.LH2022E121Special Project for Basic Scientific Research Business Expenses of the Institute of Engineering Mechanics,China Earthquake Administration under Grant No.2022C04Director’s Fund Director’s Fund of Earthquake Agency of Inner Mongolia Autonomous Region under Grant No.2023MS10。
文摘The seismic design forces of nonstructural components(NSCs)in buildings are closely related to floor acceleration response amplification.To investigate the differences in acceleration responses of structures with different structural types,fundamental periods,and seismic design levels,56 reinforced concrete and steel structures with fundamental periods ranging from 0.37 s to 5.68 s were selected.For each structure,100 sets of earthquake motions were used as inputs for elastic time history analysis.Based on the resulting 26,500 sets of floor acceleration response data,the amplification rules of peak floor acceleration/peak ground acceleration(PFA/PGA)along the height of various structures and the corresponding floor response spectrum characteristics were studied.The nonlinear changes of PFA/PGA along the height of long period structures were compared with the codes of different countries.Moreover,more suitable prediction equations were proposed based on the structural characteristics.Finally,to solve the issue that existing research still cannot accurately reflect the acceleration amplification coefficient of NSCs with different dynamic characteristics in main structures with different periods,a normalized floor response spectrum is proposed that can simultaneously consider the effects of input ground motion characteristics and the main structure,which can be better used in the seismic design of NSCs.
文摘In this editorial,we comment on an article by Wang et al.Recent literature shows an increase in research on pelvic organ prolapse(POP).Although the true incidence of POP remains uncertain,its impact on quality of life is substantial.Anatomical studies report high incidence rates,surpassing those observed in symptom-based surveys.Weakness of the endopelvic fascia is a primary anatomical risk factor for POP.Additionally,gestational diabetes mellitus(GDM)has emerged as a growing concern,as poor glycemic control increases complications for both mother and fetus.GDM and POP are interconnected,with factors like maternal obesity,macrosomia,and hormonal changes exacerbating pelvic floor dysfunction.Modifiable risk factors,such as obesity and chronic hyperglycemia,along with multiparity,instrumental deliveries,and obstetric trauma,further increase susceptibility.For patients with GDM,gynecological exams,Pelvic Organ Prolapse Quantification staging,and pelvic floor ultrasonography are valuable diagnostics,with proctological exams and magnetic resonance defecography aiding in multi-compartment prolapse diagnoses.Imaging,though uncomfortable during pregnancy,is safe in the early postpartum period.This editorial emphasizes the need for further research on the pathophysiology of GDM-related POP and offers recommendations for improving diagnosis and clinical management of patients with GDM.
基金supported by the Natural Science Foundation of Henan Province(242300421246)the National Natural Science Foundation of China(52004082,U24B2041,52174073,52274079)+2 种基金the Key Research and Development Program of Henan Province(251111320400)the Program for Science&Technology Innovation Talents in Universities of Henan Province(24HASTIT021)the Program for the Scientific and Technological Innovation Team in Universities of Henan Province(23IRTSTHN005).
文摘With the depletion of shallow mineral resources,mining operations are extending to greater depths and larger scales,increasing the risk of water inrush disasters,particularly from confined aquifers intersected by faults.This paper reviews the current state of research on fault-induced water inrushes in mining faces,examining the damage characteristics and permeability of fractured floor rock,the mechanical behavior of faults under mining stress,and the mechanisms driving water inrush.Advances in prevention technologies,risk assessment,and prediction methods are also summarized.Research shows that damage evolution in fractured floor rock,coupled with fluid-solid interactions,provides the primary pathways for water inrush.Stress-seepage coupling in porous media plays a decisive role in determining inrush potential.Mining-induced stress redistribution can activate faults,with parameters such as dip angle and internal friction angle controlling stress evolution and slip.Critical triggers include the hydraulic connectivity among faults,aquifers,and mining-induced fracture networks,followed by hydraulic erosion.A multi-pronged prevention framework has been developed,integrating precise fault detection,targeted grouting for water sealing,drainage to reduce water pressure,optimized waterproof coal pillar design,and dynamic risk assessment and prediction.However,gaps remain in understanding multi-physical field coupling under deep mining conditions,establishing quantitative criteria for fault activation-induced water inrush,and refining control technologies.Future work should focus on multi-scale numerical simulations,advanced active control measures,and intelligent,integrated prevention systems to clarify the mechanisms of fault-induced water inrush and enhance theoretical and technical support for mine safety.
基金supported by the Natural Science Foundation of Hunan Province(2024JJ6626)the Hunan Provincial Key Laboratory of Regional Hereditary Birth Defects Prevention and Control(HPKL202320),China.
文摘Objective:Pelvic floor dysfunction is common among pregnant and postpartum women and significantly impacts quality of life.This study aims to translate the German Pelvic Floor Questionnaire for Pregnant and Postpartum Women into Chinese and to evaluate its reliability and validity in the Chinese population.Methods:The questionnaire was translated using the Brislin model.A cross-sectional study was conducted among pregnant and postpartum women to assess the content validity,construct validity,Cronbach’sαcoefficient,test-retest reliability,and split-half reliability of the Chinese version.Results:A total of 72 women were included,with 6.9% being pregnant and 93.1% postpartum;the age was(32.3±3.6)years.The Chinese version of the questionnaire contains 4 dimensions and 45 items.The content validity index of individual items ranged from 0.833 to 1.000,with a scale-level content validity index of 0.977 and intraclass correlation coefficients(ICCs)exceeding 0.90.The overall Cronbach’s α coefficient was 0.891,with subscale coefficients ranging from 0.732 to 0.884(all ICCs>0.70).The testretest reliability of the total scale was 0.833,and for the 4 dimensions,bladder,bowel,prolapse,and sexual function,the values were 0.776,0.579,0.732,and 0.645,respectively.The split-half reliability was 0.74.Conclusion:The Chinese version of the questionnaire demonstrated good reliability and validity,indicating its applicability in assessing pelvic floor dysfunction and associated risk factors during pregnancy and postpartum.
文摘Conversation A(in a department store)Sara:Department store directories are helpful.Sam:They are.Today,I have to buy new furniture and bedding for my apartment.They're on the sixth floor.
基金2022 Annual Medical Science Research Project Plan of Hebei Province,No.20221111.
文摘BACKGROUND Postpartum women are at an increased risk of generalized anxiety disorder(GAD),which can negatively affect both mental health and physical recovery.Pelvic floor dysfunction,common in this population,can exacerbate psychological distress.Although pelvic floor rehabilitation is effective in physical recovery,its potential to improve psychological outcomes,especially in women with GAD,remains underexplored.AIM To evaluate the effectiveness of an individualized pelvic floor rehabilitation program in improving anxiety,pelvic floor function,and quality of life in postpartum women with GAD.METHODS A retrospective study was performed to analyze 80 postpartum women with GAD who completed a 12-week individualized pelvic floor rehabilitation program(January 2020-December 2024),combining supervised pelvic floor muscle training and psychological support.Primary outcomes were changes in GAD-7 and Hamilton anxiety rating scale(HAM-A)scores and pelvic floor function measured by surface electromyography(sEMG).Secondary outcomes included World Health Organization quality of life-BREF,pelvic floor symptom severity,and impact on daily activities(pelvic floor impact questionnaire).Assessments were conducted at baseline and 6 and 12 weeks during the intervention period.RESULTS Significant improvements were observed in anxiety measures,with mean GAD-7 scores decreasing from 14.8±3.2 at baseline to 8.2±2.9 at week 12(P<0.001)and HAM-A scores decreasing from 22.6±4.5 to 12.4±3.8(P<0.001).Pelvic floor function showed substantial enhancement,with sEMG amplitude increasing from 22.4±5.6μV to 35.9±6.8μV(P<0.001).Quality of life improved across all domains,with the most significant improvements in psychological(28.5%increase)and physical health(25.8%increase).Program adherence was 91.5%for the supervised sessions,and no serious adverse events were reported.CONCLUSION Individualized pelvic floor rehabilitation training effectively improves both psychological and functional outcomes in postpartum women with GAD.The high adherence and significant outcomes make this integrated approach feasible and effective.
文摘Pelvic floor dysfunction(PFD),including conditions such as stress urinary incontinence,pelvic organ prolapse,and fecal incontinence,significantly affects women's quality of life and their physical and mental health.With advancement of digital medicine,the systematic collection of data and the high-quality development of database platforms have increasingly become central pillars of PFD research and management.We systematically review the developmental stages of PFDrelated databases.We then conduct a comparative analysis of representative international and domestic platforms,examining key aspects including organizational structures and construction models,data sources and integration strategies,core functionalities,data quality control and standardization,data security and access management,and research applications.Finally,based on the current status of PFD database development both globally and in China,we offer recommendations to strengthen data infrastructure and guide future directions.The findings may serve as a valuable reference for the optimization of PFD databases worldwide.
基金supported by the European Union-Next Generation EU instrument and the Research Council of Finland funding(grants 323843,347782,353218,355142,and 357902)INAR RI research infrastructure。
文摘The duration of snow cover has shortened in the boreal region,and the amount of seasonal snow decreased.This affects the coupling between soil and air temperatures and may thus lead to colder soil and deeper soil frost.We prevented snow reaching the forest floor for two winters in mature boreal forest and studied how that affects tree and forest floor processes.The studied species were Scots pine,Norway spruce,silver birch,and a dwarf shrub bilberry.Decreased soil temperature,due to the lack of snow cover,decreased forest floor respiration in winter and spring.Simultaneously,response of respiration to temperature seemed to increase,perhaps due to the exposure of forest floor vegetation to cold air temperature.Indeed,lack of snow cover induced mortality of bilberry,but the remaining ramets grew more in height and their average leaf size was larger likely to compensate for the lost plant biomass.Lack of snow cover also affected tree hydraulics as tree water uptake was decreased in spring,and the start of the sap season delayed in birch.Pine and birch tended to grow less in the snow exclusion treatment(differences not statistically significant),whereas spruce grew more.Coarse root traits,e.g.water content and cellular frost damages,were not affected by the snow exclusion treatment.The results of this case study increase our understanding on the effects of changing snow cover on spring-time tree and forest floor processes in mature boreal forest,but also reveal the need for further studies on mature trees.
基金financially supported by the National Natural Science Foundation of China(grant numbers:42077265,41927806)the Science and Technology Project of Gansu Provincial Department of Transportation(grant number:2023-12)the Gansu Science and Technology Department of Key Projects(grant number:21YF5FA002)。
文摘Floor heave is a common water-induced issue of loess tunnels.However,the mechanism of tunnel floor heave induced by repeated rainfall or irrigation remains poorly understood.This study analyzes moisture variation at the tunnel base and invert deformation through a 15-year survey of an operational loess tunnel.An improved Green-Ampt model was developed to capture the effects of interannual repeated infiltration on water content,permeability,and matric suction at the tunnel base.The model was validated using soil column infiltration tests.The calculated wetting front depth was incorporated into the tunnel numerical simulation to analyze the development of floor heave and assess its several influencing factors.Results show the base average water content at the tunnel base increases exponentially with operational years.After 15 years,over 50%of the monitored sections reach saturation,leading to significant invert uplift.Based on the plastic limit,saturation water content,and liquid limit of loess,floor heave is categorized into four levels with deformation thresholds at 10,25,and 50 mm.The modified Green-Ampt model is suitable for repeated infiltration conditions and offers practical guidance.Neglecting hydraulic deterioration due to repeated infiltration may lead to significant prediction errors.Numerical simulations reveal that the inverted arch uplift height,width,and height-to-width ratio increase linearly with the rise in the number of infiltration events.The uplift deformation follows Gaussian distribution in both cross and longitudinal sections,forming aΛ-shaped floor heave.The influence of infiltration duration,water content,horizontal infiltration,asymmetric infiltration,burial depth,and the number of infiltration events enhanced successively on floor heave.This model facilitates the prediction of floor heave under dynamic hydrological conditions during long-term tunnel operation.
基金supported by the Tianjin Enterprise Science and Technology Commissioner Project(Grant No.23YDTPJC00740,Grant No.24YDTPJC00610)the Tianjin Tiankai Higher Education Science and Technology Innovation Park Enterprise R&D Special Project(Grant No.23YFZXYC00027).
文摘The shop floor dynamic scheduling system based on human-computer interaction is the use of computer-aided decision-making and human-computer interaction to solve the dynamic scheduling problem.A human-computer interaction interface based on Gantt chart is designed,which can not only comprehensively and quantitatively represent the scheduling process and scheduling scheme,but also have friendly human-computer interaction performance.The data transmission and interaction architecture is constructed to realize the rapid response to shop floor disturbance events.A priority calculation algorithm integrating priority rules and dispatcher preference is proposed,which realizes the automatic calculation of priority for the dispatcher's reference and reduces theirburden.A man-machine interactive shop floor dynamic scheduling strategy is proposed.When solving the dynamic flexible job shop scheduling problem caused by machine tool breakdown and urgent order,the origin moments obtained by using this strategy are 0.4190 and 0.3703 respectively.As can be seen from the origin moment indicator,the dynamic shop floor scheduling system based on the human-computer interaction is efficient and reliable in solving dynamic scheduling problems,and related strategies of this system are also feasible and stable.
基金financially supported by the National Natural Science Foundation of China(Grant No.52008039)the Guizhou Provincial Department of Transportation Science and Technology Project(Project No.2024-121-043)the Changsha University of Science and Technology Graduate Research Innovation Project(Grant No.CLSJCX23036).
文摘Floor heave is a common defect in mountainous tunnels.It is critical but challenging to predict the risk of floor heave,as traditional methods often fail to characterize this phenomenon effectively.This study proposes a data-driven approach utilizing a support vector machine(SVM)optimized by the sparrow search algorithm(SSA)to address the issue.The model was developed and validated using a dataset collected from 100 tunnels.Shapley value analysis was conducted to identify the key features influencing floor heave defects.Moreover,a committee-based uncertainty quantification method is presented to evaluate the reliability of each prediction.The results show that:(1)Data feature engineering and SSA play pivotal roles in expediting the convergence of the SVM model.(2)Groundwater and high in situ stress are key factors contributing to tunnel floor heave.(3)In comparison to backpropagation(BP)neural networks,the SSA-SVM demonstrates superior robustness in handling imperfect and limited data.(4)The committee-based uncertainty quantification method is proven effective to evaluate the trustworthiness of each prediction.This data-driven surrogate model offers an effective strategy for understanding the factors that impact tunnel floor defects and accurately predicting tunnel floor heave deformation.
文摘This paper presents a comprehensive experimental and numerical investigation of radiant floor heating(RFH)systems integrated with phase changematerial(PCM)-based thermal energy storage(TES).The study compares two underfloor pipe configurations:double serpentine and spiral.It also looks at how well a paraffin wax PCM system works with compact heat exchanger-type TES units during winter in Iraq.Key performance indicators including discharge temperature,heat transfer rate,liquid fraction evolution,and temperature uniformity were assessed through in situ experimental measurements and ANSYS fluent simulations.Results demonstrate that the spiral design provides slightly more uniform temperature distribution on the tile surface at an inlet water temperature of 55℃,with an average difference of approximately 0.5%,the serpentine layout exhibits higher slab temperature distribution by about 0.66%.Notably,the serpentine configuration shows superior thermal homogeneity and heat distribution,with a 15.05%increase in heat gain at a 55℃ inlet temperature compared to the spiral design.The performance gap between the two layouts narrows as the inlet temperature increases from 50℃ in 5℃ increments by approximately 4.1%,3.7%,and 1.7%,respectively.Higher inlet temperatures also improve PCM discharging and charging rates,improving energy storage utilization.The findings provide significant design guidelines for sustainable heating systems for cold climates.
基金the Independent Research of the State Key Laboratory of Coal Resources and Mine Safety(No. SKLCRSM09X02)the Open Research Fund of the State Key Laboratory of Coal Resources and Mine Safety(No.08KF12)the Graduate Students of Jiangsu Province Innovation Program Funded Projects(No.CX09B_120Z) for their financial support
文摘Gateways at faces of great mining heights are mostly driven along the roof of coal seams.For gateway height restrictions,a 1-3 m floor coal is retained,leaving a triangular floor coal at the face ends,causing a loss of coal.In order to improve coal recovery rates and to ensure efficiency of equipment at coal mining faces,we investigated suitable retention methods and recovery technology of floor coal at face ends.The upper floor coal can directly be recovered by a shearer with floor dinting.The lower floor coal is recovered by shearer with floor dinting after advanced floor dinting and retaining a step for protecting coal sides in a haulage gateway.Field practice shows that this method can improve the coal recovery rates at fully mechanized working faces with great mining heights.
文摘To evaluate the thermal performance of a low-temperature electrical radiant floor heating system,an experimental facility equipped with a constant temperature chamber and different specimen floors is designed and built.The heating cable is installed in the floor slab with a unit-rated power of 30 W/m.Twenty-four different schemes are worked out and tested,which include three kinds of composite floor structures and eight kinds of cable distances.The cable distances are 30,40,50,60,80,100,130,150 mm.The main affective factors of the thermal performance and their influencing regularity are discussed.The experimental results show that the system has good stability and reliability,and the ratio of the radiation heat-transfer rate to the gross heat-transfer rate is greater than 50%.When the floor structure and the cable distance are fixed,the gross heat-transfer rate of the upper floor surface has a maximum value at an optimal cable distance.Under the experimental conditions in this paper,the optimal cable distance is 50 mm.
基金The authors would like to thank Dr.Serkan Saydam and Dr.Sungsoon Mo from the University of New South Wales for their kind support and guidance during the preparation of this manuscript.
文摘Estimating the overall floor stability in a coal mine using deterministic methods which require complex engineering properties of floor strata is desirable,but generally it is impractical due to the difficulty of gathering essential input data.However,applying a quantitative methodology to describe floor quality with a single number provides a practical estimate for preliminary assessment of floor stability.The coal mine floor rating(CMFR)system,developed by the University of New South Wales(UNSW),is a rockmass classification system that provides an indicator for the competence of floor strata.The most significant components of the CMFR are uniaxial compressive strength and discontinuity intensity of floor strata.In addition to the competence of the floor,depth of cover and stress notch angle are input parameters used to assess the preliminary floor stability.In this study,CMFR methodology was applied to a Central Appalachian Coal Mine that intermittently experienced floor heave.Exploratory drill core data,overburden maps,and mine plans were utilized for the study.Additionally,qualitative data(failure/non-failure)on floor conditions of the mine entries near the core holes was collected and analyzed so that the floor quality and its relation to entry stability could be estimated by statistical methods.It was found that the current CMFR classification system is not directly applicable in assessing the floor stability of the Central Appalachian Coal Mine.In order to extend the applicability of the CMFR classification system,the methodology was modified.A calculation procedure of one of the CMFR classification system’s components,the horizontal stress rating(HSR),was changed and new parameters were added to the HSR.
