The gear transmission system directly affects the operational performance of high-speed trains(HST).However,current research on gear transmission systems of HST often overlooks the effects of gear eccentricity and run...The gear transmission system directly affects the operational performance of high-speed trains(HST).However,current research on gear transmission systems of HST often overlooks the effects of gear eccentricity and running resistance,and the dynamic models of gear transmission system are not sufficiently comprehensive.This paper aims to establish an electromechanical coupling dynamic model of HST traction transmission system and study its electromechanical coupling vibration characteristics,in which the internal excitation factors such as gear eccentricity,time-varying meshing stiffness,backlash,meshing error,and external excitation factors such as electromagnetic torque and running resistance are stressed.The research results indicate that gear eccentricity and running resistance have a significant impact on the stability of the system,and gear eccentricity leads to intensified system vibration and decreased anti-interference ability.In addition,the characteristic frequency of gear eccentricity can be extracted from mechanical signals and current signals as a preliminary basis for eccentricity detection,and electrical signals can also be used to monitor changes in train running resistance in real time.The results of this study provide some useful insights into designing dynamic performance parameters for HST transmission systems and monitoring train operational states.展开更多
Purpose We aimed to investigate the effects of running shoe longitudinal bending stiffness(LBS)and midsole energy return on running economy and ankle mechanics and energetics.Methods PubMed,Scopus,SPORTDiscus,Embase,C...Purpose We aimed to investigate the effects of running shoe longitudinal bending stiffness(LBS)and midsole energy return on running economy and ankle mechanics and energetics.Methods PubMed,Scopus,SPORTDiscus,Embase,CINAHL,and Web of Science were systematically searched for this meta-analysis.Crossover studies comparing the effects of running shoe LBS and/or midsole energy return on at least 1 of the following outcomes:running economy,ankle plantarflexion moment,work,power,or angular velocity were included.Results Of the 2453 studies screened,48 were included(n=878).Results indicated that advanced footwear technologies(AFTs)significantly reduced oxygen consumption(standardized mean difference=–0.44,95%confidence interval:–0.60 to–0.28),p<0.001)as well as peak ankle moments and positive/negative ankle work and power.However,neither LBS nor midsole energy return alone significantly affected oxygen consumption,ankle moments,positive and negative work,or positive power.The effects of AFTs were moderated by the training status and speed of the runner.The quality of evidence for all outcomes were low or very low for all outcomes except the effect of LBS on negative ankle work.Conclusion AFT may improve running economy by minimizing ankle moments,work,and power.The absence of significant independent effects of LBS and midsole energy return suggests that the benefits of AFTs arise from the interaction of these properties.Further research is necessary to understand the mechanisms for improved running performance in AFTs.展开更多
This study investigated the validity and sensitivity of a custom-made shoelace tensile testing system.The aim was to analyze the distribution pattern of shoelace tension in different positions and under different tigh...This study investigated the validity and sensitivity of a custom-made shoelace tensile testing system.The aim was to analyze the distribution pattern of shoelace tension in different positions and under different tightness levels during running.Mechanical tests were conducted using 16 weights,and various statistical analyses,including linear regression,Bland-Altman plots,coefficient of variation,and intraclass correlation coefficient,were performed to assess the system’s validity.Fifteen male amateur runners participated in the study,and three conditions(loose,comfortable,and tight)were measured during an upright stance.The system utilized VICON motion systems,a Kistler force plate,and a Photoelectric gate speed measurement system.Results showed a linear relationship between voltage and load at the three sensors(R2≥0.9997).Bland-Altman plots demonstrated 95%prediction intervals within±1.96SD from zero for all sensors.The average coefficient of variation for each sensor was less than 0.38%.Intraclass correlation coefficient values were larger than 0.999(p<0.0001)for each sensor.The peak tension of the front shoelace was greater than that of the front and middle when the shoelace was loose and tight.The rear shoelace had the highest tension force.The study also found that shoelace tension varied throughout the gait cycle during running.Overall,this research provides a novel and validated method for measuring shoelace tensile stress,which has implications for developing automatic shoelace fastening systems.展开更多
Objective:Running-related musculoskeletal injuries(RRMIs),especially stemming from overuse,frequently occur in runners.This study aimed to systematically review the literature and determine the incidence and prevalenc...Objective:Running-related musculoskeletal injuries(RRMIs),especially stemming from overuse,frequently occur in runners.This study aimed to systematically review the literature and determine the incidence and prevalence proportion of RRMIs by anatomic location and specific pathology.Methods:An electronic database search with no date beginning restrictions was performed in SPORTDiscus,PubMed,and MEDLINE up to June 2020.Prospective studies were used to find the anatomic location and the incidence proportion of each RRMI,whereas retrospective or cross-sectional studies were used to find the prevalence proportion of each RRMI.A separate analysis for ultramarathon runners was performed.Results:The overall injury incidence and prevalence were 40.2%±18.8%and 44.6%±18.4%(mean±SD),respectively.The knee,ankle,and lower leg accounted for the highest proportion of injury incidence,whereas the knee,lower leg,and foot/toes had the highest proportion of injury prevalence.Achilles tendinopathy(10.3%),medial tibial stress syndrome(9.4%),patellofemoral pain syndrome(6.3%),plantar fasciitis(6.1%),and ankle sprains(5.8%)accounted for the highest proportion of injury incidence,whereas patellofemoral pain syndrome(16.7%),medial tibial stress syndrome(9.1%),plantar fasciitis(7.9%),iliotibial band syndrome(7.9%),and Achilles tendinopathy(6.6%)had the highest proportion of injury prevalence.The ankle(34.5%),knee(28.1%),and lower leg(12.9%)were the 3 most frequently injured sites among ultramarathoners.Conclusion:The injury incidence proportions by anatomic location between ultramarathoners and non-ultramarathoners were not significantly different(p=0.798).The pathologies with the highest incidence proportion of injuries were anterior compartment tendinopathy(19.4%),patellofemoral pain syndrome(15.8%),and Achilles tendinopathy(13.7%).The interpretation of epidemiological data in RRMIs is limited due to several methodological issues encountered.展开更多
The governmental electric utility and the private sector are joining hands to meet the target of electrifying all households by 2024.However,the aforementioned goal is challenged by households that are scattered in re...The governmental electric utility and the private sector are joining hands to meet the target of electrifying all households by 2024.However,the aforementioned goal is challenged by households that are scattered in remote areas.So far,Solar Home Systems(SHS)have mostly been applied to increase electricity access in rural areas.SHSs have continuous constraints to meet electricity demands and cannot run income-generating activities.The current research presents the feasibility study of electrifying Remera village with the smart microgrid as a case study.The renewable energy resources available in Remera are the key sources of electricity in that village.The generation capacity is estimated based on the load profile.The microgrid configurations are simulated with HOMER,and the genetic algorithm is used to analyze the optimum cost.By analyzing the impact of operation and maintenance costs,the results show that the absence of subsidies increases the levelized cost of electricity(COE)five times greater than the electricity price from the public utility.The microgrid made up of PV,diesel generator,and batteries proved to be the most viable solution and ensured continuous power supply to customers.By considering the subsidies,COE reaches 0.186$/kWh,a competitive price with electricity from public utilities in Rwanda.展开更多
Running safety assessment and tracking irregularity parametric sensitivity analysis of high-speed maglev train-bridge system are of great concern,especially need perfect refinement models in which all properties can b...Running safety assessment and tracking irregularity parametric sensitivity analysis of high-speed maglev train-bridge system are of great concern,especially need perfect refinement models in which all properties can be well characterized based on various stochastic excitations.A three-dimensional refined spatial random vibration analysis model of high-speed maglev train-bridge coupled system is established in this paper,in which multi-source uncertainty excitation can be considered simultaneously,and the probability density evolution method(PDEM)is adopted to reveal the system-specific uncertainty dynamic characteristic.The motion equation of the maglev vehicle model is composed of multi-rigid bodies with a total 210-degrees of freedom for each vehicle,and a refined electromagnetic force-air gap model is used to account for the interaction and coupling effect between the moving train and track beam bridges,which are directly established by using finite element method.The model is proven to be applicable by comparing with Monte Carlo simulation.By applying the proposed stochastic framework to the high maglev line,the random dynamic responses of maglev vehicles running on the bridges are studied for running safety and stability assessment.Moreover,the effects of track irregularity wavelength range under different amplitude and running speeds on the coupled system are investigated.The results show that the augmentation of train speed will move backward the sensitive wavelength interval,and track irregularity amplitude influences the response remarkably in the sensitive interval.展开更多
Dynamic running law of the hydraulic driving system decides the hoisting cage velocity curve in a hoisting cycle and is decided by the characteristic of the hydraulic driving system and by the operating speed of hoist...Dynamic running law of the hydraulic driving system decides the hoisting cage velocity curve in a hoisting cycle and is decided by the characteristic of the hydraulic driving system and by the operating speed of hoist driver. The paper studies the dynamic running law of hydraulic driving system, analyses the influence of driver operating speed on the dynamic running characteristic, and points out the reasonable driver operating speed to control the dynamic stress in rope and to reduce the oscillation of rope system.展开更多
An integrated monitoring system for running parameters of key mining equipmenton the basis of condition monitoring technology and modern communication networktechnology was developed.The system consists of a client co...An integrated monitoring system for running parameters of key mining equipmenton the basis of condition monitoring technology and modern communication networktechnology was developed.The system consists of a client computer with functions ofsignal acquisition and processing, and a host computer in the central control room.Thesignal acquisition module of the client computer can collect the running parameters fromvarious monitoring terminals in real-time.The DSP high-speed data processing system ofthe main control module can quickly achieve the numerical calculation for the collectedsignal.The signal modulation and signal demodulation are completed by the frequencyshift keying circuit and phase-locked loop frequency circuit, respectively.Finally, the signalis sent to the host computer for logic estimation and diagnostic analysis using the networkcommunication technology, which is helpful for technicians and managers to control therunning state of equipment.展开更多
Spinal cord injury necessitates effective rehabilitation strategies, with exercise therapies showing promise in promoting recovery. This study investigated the impact of rehabilitation exercise on functional recovery ...Spinal cord injury necessitates effective rehabilitation strategies, with exercise therapies showing promise in promoting recovery. This study investigated the impact of rehabilitation exercise on functional recovery and morphological changes following thoracic contusive spinal cord injury. After a 7-day recovery period after spinal cord injury, mice were assigned to either a trained group(10 weeks of voluntary running wheel or forced treadmill exercise) or an untrained group. Bi-weekly assessments revealed that the exercise-trained group, particularly the voluntary wheel exercise subgroup, displayed significantly improved locomotor recovery, more plasticity of dopaminergic and serotonin modulation compared with the untrained group. Additionally, exercise interventions led to gait pattern restoration and enhanced transcranial magnetic motor-evoked potentials. Despite consistent injury areas across groups, exercise training promoted terminal innervation of descending axons. In summary, voluntary wheel exercise shows promise for enhancing outcomes after thoracic contusive spinal cord injury, emphasizing the role of exercise modality in promoting recovery and morphological changes in spinal cord injuries. Our findings will influence future strategies for rehabilitation exercises, restoring functional movement after spinal cord injury.展开更多
Purpose This study aimed to investigate whether there is a systematic change of leg muscle activity,as quantified by surface electromyography(EMG),throughout a standard running footwear assessment protocol at a predet...Purpose This study aimed to investigate whether there is a systematic change of leg muscle activity,as quantified by surface electromyography(EMG),throughout a standard running footwear assessment protocol at a predetermined running speed.Methods Thirty-one physically active adults(15 females and 16 males)completed 5 testing rounds consisting of overground running trials at a speed of 3.5 m/s.The level of muscle activity from 6 major leg muscles was recorded using surface EMG.The variables assessed were the EMG total intensity as a function of time and the cumulative EMG overall intensity.Systematic effects of the chronological testing round(independent variable)on the normalized EMG overall intensity(dependent variable)were examined using Friedman analysis of variates and post hoc pairwise Wilcoxon signed-rank tests(α=0.05).Results There was a systematic reduction in overall EMG intensity for all 6 muscles over the time course of the running protocol(p<0.001)until the fourth testing round when EMG intensities reached a steady state.The one exception was the biceps femoris muscle,which showed a significant reduction of EMG intensity during the stance phase(p<0.001)but not the swing phase(p=0.16).Conclusion While running at a predetermined speed,the neuromuscular system undergoes an adaptation process characterized by a progressive reduction in the activity level of major leg muscles.This process may represent an optimization strategy of the neuromuscular system towards a more energetically efficient running style.Future running protocols should include a familiarization period of at least 7 min or 600 strides of running at the predetermined speed.展开更多
Helicopter blade running elevation measurement is an important measure target in helicopter blade dynamic balance experimentation. The elevation influences the helicopter＇ s security and other performance capabilitie...Helicopter blade running elevation measurement is an important measure target in helicopter blade dynamic balance experimentation. The elevation influences the helicopter＇ s security and other performance capabilities. In testing, however, it has been difficult to measure the elevation when the rotor reaches high speeds. To get a simple, fast and highly accurate measurement system, photo electricity technology was applied to measuring the blade running elevation. Discussed is the measurement principle of blade running elevation, tire design of the measurement system and analysis of the measurement precision.展开更多
Since the fi rst cases of coronavirus disease 2019(COVID-19)caused by severe acute respiratory syndrome coro-navirus 2(SARS-CoV-2)were reported at the end of 2019,this infection has spread around the globe,becoming a ...Since the fi rst cases of coronavirus disease 2019(COVID-19)caused by severe acute respiratory syndrome coro-navirus 2(SARS-CoV-2)were reported at the end of 2019,this infection has spread around the globe,becoming a pandemic.The use of face masks and respirators is an important public health measure to reduce or prevent transmission of SARS-CoV-2.Here we discuss the hypothetical mechanisms by which exercise with face masks or respirators can induce detrimental effects on the cardiovascular system,potentially explaining adverse events such as cardiac arrhythmias and spontaneous pneumothorax.Although sudden death associated with the wearing of a face mask during running is a rare event,the risk is higher especially in those with existing cardiac comorbidities.In such cases,a mask designed specifi cally for runners with no or few side effects of oxygen defi ciency should be considered instead.展开更多
Urban environments offer a wealth of opportunities for residents to respite from their hectic life.Outdoor running or jogging becomes increasingly popular of an option.Impacts of urban environments on outdoor running,...Urban environments offer a wealth of opportunities for residents to respite from their hectic life.Outdoor running or jogging becomes increasingly popular of an option.Impacts of urban environments on outdoor running,despite some initial studies,remain underexplored.This study aims to establish an analytical framework that can holistically assess the urban environment on the healthy vitality of running.The proposed framework is applied to two modern Chinese cities,i.e.,Guangzhou and Shenzhen.We construct three interpretable random forest models to explore the non-linear relationship between environmental variables and running intensity(RI)through analyzing the runners'trajectories and integrating with multi-source urban big data(e.g.,street view imagery,remote sensing,and socio-economic data)across the built,natural,and social dimensions,The findings uncover that road density has the greatest impact on RI,and social variables(e.g.,population density and housing price)and natural variables(e.g.,slope and humidity)all make notable impact on outdoor running.Despite these findings,the impact of environmental variables likely change across different regions due to disparate regional construction and micro-environments,and those specific impacts as well as optimal thresholds also alter.Therefore,construction of healthy cities should take the whole urban environment into account and adapt to local conditions.This study provides a comprehensive evaluation on the influencing variables of healthy vitality and guides sustainable urban planning for creating running-friendly cities.展开更多
BACKGROUND Wound management is an essential part of emergency medicine practice.A good suture technique should deal a complex irregular traumatic wound without any complications of dehiscence/gaping,infection,delayed ...BACKGROUND Wound management is an essential part of emergency medicine practice.A good suture technique should deal a complex irregular traumatic wound without any complications of dehiscence/gaping,infection,delayed wound healing,frequent dressings and further stay in hospital.There is no ideal technique of suturing for any wound.In pursuit of the new techniques,we have introduced a new suturing technique called combined oblique and vertical everting running(COVER)stitch which has showed good healing with less complications.AIM To compare the outcomes between the COVER stitch and conventional suturing group.METHODS In this study,we included 40 cases which were divided into two groups.Group 1 patients were managed by COVER stitch,and group 2 patients underwent conventional suturing for their wounds.The outcomes were measured in terms of scar quality,suturing duration and length of suture material used,suturing related complications and suture removal time which were compared by t-test usingχ^(2) test.RESULTS Better results were seen in COVER stitch than the conventional suturing.COVER group had significantly better results in terms of time taken for suture,amount suture material used and time taken for suture removal compared to the conventional group.No wound related complications were seen in this group.Moreover,scar formed was also better in COVER group.CONCLUSION COVER stitch is another new technique which can be used to deal simple to complex wounds and it is an emerging idea with good healthy scars with less complications.展开更多
Poplars and the Gobi,camels and the desert,mulberry trees and the Silk Road,yaks and the snowcapped mountains,even the monkshood with its lovely but poisonous blossoms once used by hunters,and the mythical Cordyceps s...Poplars and the Gobi,camels and the desert,mulberry trees and the Silk Road,yaks and the snowcapped mountains,even the monkshood with its lovely but poisonous blossoms once used by hunters,and the mythical Cordyceps sinensis,a creature that is grass in summer and worm in winter.These plants and animals,wrapped in legend and story,have long captured the imagination.They are the emblematic life forms of China’s vast western lands.展开更多
Subgrade settlement is a common issue in soil ground within earthquake-prone regions,posing a threat to the safe operation of train-slab track coupled system(TSCS)in high-speed railways(HSRs).This study aims to analyz...Subgrade settlement is a common issue in soil ground within earthquake-prone regions,posing a threat to the safe operation of train-slab track coupled system(TSCS)in high-speed railways(HSRs).This study aims to analyze the mechanical behavior evolution of TSCS under subgrade settlement and earthquake excitation.The refined numerical model of slab track under subgrade differential settlement is established.The short settlement wavelength of 10 m causes the separation between the base and subgrade.The dynamic model of TSCS under subgrade settlement and earthquake excitation is developed.The dynamic response of TSCS exhibits more pronounced fluctuations under the combined effects of subgrade settlement and earthquake excitation than under the effects of settlement or earthquake alone.The evaluation indexes for the running safety of train on slab track under different settlement wavelengths exhibit varying degrees of increase with settlement amplitude and are particularly sensitive to the short settlement wavelength of 10 m.The wheel unloading rate and derailment coefficient of TSCS increase with earthquake intensity.Under the settlement wavelength of 10 m and amplitude of 20 mm,the wheel unloading rate of TSCS exceeds the allowable limit when the earthquake intensity exceeds 0.17g,and the derailment coefficient exceeds the allowable limit when the earthquake intensity surpasses 0.29g.展开更多
A real-life milk run system designing problem of an engine manufacturer adopted JIT(just-in-time)production is studied.In the process of milk run system planning and design,the supply base is identified and a supplier...A real-life milk run system designing problem of an engine manufacturer adopted JIT(just-in-time)production is studied.In the process of milk run system planning and design,the supply base is identified and a supplier site map is plotted for an arrangement of routes on which parts are periodically collected in a JIT manner from many scattered suppliers.With unit load designing,vehicle choosing and fleet sizing,pickup routing,vehicle assigning and scheduling problems are studied.Among these problems,a CVRP problem is identified and formulated as the key optimization in designing this milk run system,and it is solved through an optimization process.This tactical planning and optimization process gives a good solution to the real problem,and may shed light on the planning of similar systems.展开更多
According to the characteristics of circular agricultural mode focusing on pig farming and by dint of system dynamics mode-based analysis techniques to analyze the characteristics,the operation force for the recycling...According to the characteristics of circular agricultural mode focusing on pig farming and by dint of system dynamics mode-based analysis techniques to analyze the characteristics,the operation force for the recycling agricultural system focusing on pig farming was put forward.展开更多
基金supported by Sichuan Science and Technology Program(Grant No.2020YFH0080)the National Natural Science Foundation of China(Grant No.51475386)the National Basic Research Project of China(973 Program,Grant No.2015CB654801).
文摘The gear transmission system directly affects the operational performance of high-speed trains(HST).However,current research on gear transmission systems of HST often overlooks the effects of gear eccentricity and running resistance,and the dynamic models of gear transmission system are not sufficiently comprehensive.This paper aims to establish an electromechanical coupling dynamic model of HST traction transmission system and study its electromechanical coupling vibration characteristics,in which the internal excitation factors such as gear eccentricity,time-varying meshing stiffness,backlash,meshing error,and external excitation factors such as electromagnetic torque and running resistance are stressed.The research results indicate that gear eccentricity and running resistance have a significant impact on the stability of the system,and gear eccentricity leads to intensified system vibration and decreased anti-interference ability.In addition,the characteristic frequency of gear eccentricity can be extracted from mechanical signals and current signals as a preliminary basis for eccentricity detection,and electrical signals can also be used to monitor changes in train running resistance in real time.The results of this study provide some useful insights into designing dynamic performance parameters for HST transmission systems and monitoring train operational states.
基金supported by a National Health and Medical Research Council(NHMRC)Investigator Grant Emerging Leadership Level 1(Grant No.2017012).
文摘Purpose We aimed to investigate the effects of running shoe longitudinal bending stiffness(LBS)and midsole energy return on running economy and ankle mechanics and energetics.Methods PubMed,Scopus,SPORTDiscus,Embase,CINAHL,and Web of Science were systematically searched for this meta-analysis.Crossover studies comparing the effects of running shoe LBS and/or midsole energy return on at least 1 of the following outcomes:running economy,ankle plantarflexion moment,work,power,or angular velocity were included.Results Of the 2453 studies screened,48 were included(n=878).Results indicated that advanced footwear technologies(AFTs)significantly reduced oxygen consumption(standardized mean difference=–0.44,95%confidence interval:–0.60 to–0.28),p<0.001)as well as peak ankle moments and positive/negative ankle work and power.However,neither LBS nor midsole energy return alone significantly affected oxygen consumption,ankle moments,positive and negative work,or positive power.The effects of AFTs were moderated by the training status and speed of the runner.The quality of evidence for all outcomes were low or very low for all outcomes except the effect of LBS on negative ankle work.Conclusion AFT may improve running economy by minimizing ankle moments,work,and power.The absence of significant independent effects of LBS and midsole energy return suggests that the benefits of AFTs arise from the interaction of these properties.Further research is necessary to understand the mechanisms for improved running performance in AFTs.
文摘This study investigated the validity and sensitivity of a custom-made shoelace tensile testing system.The aim was to analyze the distribution pattern of shoelace tension in different positions and under different tightness levels during running.Mechanical tests were conducted using 16 weights,and various statistical analyses,including linear regression,Bland-Altman plots,coefficient of variation,and intraclass correlation coefficient,were performed to assess the system’s validity.Fifteen male amateur runners participated in the study,and three conditions(loose,comfortable,and tight)were measured during an upright stance.The system utilized VICON motion systems,a Kistler force plate,and a Photoelectric gate speed measurement system.Results showed a linear relationship between voltage and load at the three sensors(R2≥0.9997).Bland-Altman plots demonstrated 95%prediction intervals within±1.96SD from zero for all sensors.The average coefficient of variation for each sensor was less than 0.38%.Intraclass correlation coefficient values were larger than 0.999(p<0.0001)for each sensor.The peak tension of the front shoelace was greater than that of the front and middle when the shoelace was loose and tight.The rear shoelace had the highest tension force.The study also found that shoelace tension varied throughout the gait cycle during running.Overall,this research provides a novel and validated method for measuring shoelace tensile stress,which has implications for developing automatic shoelace fastening systems.
文摘Objective:Running-related musculoskeletal injuries(RRMIs),especially stemming from overuse,frequently occur in runners.This study aimed to systematically review the literature and determine the incidence and prevalence proportion of RRMIs by anatomic location and specific pathology.Methods:An electronic database search with no date beginning restrictions was performed in SPORTDiscus,PubMed,and MEDLINE up to June 2020.Prospective studies were used to find the anatomic location and the incidence proportion of each RRMI,whereas retrospective or cross-sectional studies were used to find the prevalence proportion of each RRMI.A separate analysis for ultramarathon runners was performed.Results:The overall injury incidence and prevalence were 40.2%±18.8%and 44.6%±18.4%(mean±SD),respectively.The knee,ankle,and lower leg accounted for the highest proportion of injury incidence,whereas the knee,lower leg,and foot/toes had the highest proportion of injury prevalence.Achilles tendinopathy(10.3%),medial tibial stress syndrome(9.4%),patellofemoral pain syndrome(6.3%),plantar fasciitis(6.1%),and ankle sprains(5.8%)accounted for the highest proportion of injury incidence,whereas patellofemoral pain syndrome(16.7%),medial tibial stress syndrome(9.1%),plantar fasciitis(7.9%),iliotibial band syndrome(7.9%),and Achilles tendinopathy(6.6%)had the highest proportion of injury prevalence.The ankle(34.5%),knee(28.1%),and lower leg(12.9%)were the 3 most frequently injured sites among ultramarathoners.Conclusion:The injury incidence proportions by anatomic location between ultramarathoners and non-ultramarathoners were not significantly different(p=0.798).The pathologies with the highest incidence proportion of injuries were anterior compartment tendinopathy(19.4%),patellofemoral pain syndrome(15.8%),and Achilles tendinopathy(13.7%).The interpretation of epidemiological data in RRMIs is limited due to several methodological issues encountered.
文摘The governmental electric utility and the private sector are joining hands to meet the target of electrifying all households by 2024.However,the aforementioned goal is challenged by households that are scattered in remote areas.So far,Solar Home Systems(SHS)have mostly been applied to increase electricity access in rural areas.SHSs have continuous constraints to meet electricity demands and cannot run income-generating activities.The current research presents the feasibility study of electrifying Remera village with the smart microgrid as a case study.The renewable energy resources available in Remera are the key sources of electricity in that village.The generation capacity is estimated based on the load profile.The microgrid configurations are simulated with HOMER,and the genetic algorithm is used to analyze the optimum cost.By analyzing the impact of operation and maintenance costs,the results show that the absence of subsidies increases the levelized cost of electricity(COE)five times greater than the electricity price from the public utility.The microgrid made up of PV,diesel generator,and batteries proved to be the most viable solution and ensured continuous power supply to customers.By considering the subsidies,COE reaches 0.186$/kWh,a competitive price with electricity from public utilities in Rwanda.
基金Project(2023YFB4302500)supported by the National Key R&D Program of ChinaProject(52078485)supported by the National Natural Science Foundation of ChinaProjects(2021-Major-16,2021-Special-08)supported by the Science and Technology Research and Development Program Project of China Railway Group Limited。
文摘Running safety assessment and tracking irregularity parametric sensitivity analysis of high-speed maglev train-bridge system are of great concern,especially need perfect refinement models in which all properties can be well characterized based on various stochastic excitations.A three-dimensional refined spatial random vibration analysis model of high-speed maglev train-bridge coupled system is established in this paper,in which multi-source uncertainty excitation can be considered simultaneously,and the probability density evolution method(PDEM)is adopted to reveal the system-specific uncertainty dynamic characteristic.The motion equation of the maglev vehicle model is composed of multi-rigid bodies with a total 210-degrees of freedom for each vehicle,and a refined electromagnetic force-air gap model is used to account for the interaction and coupling effect between the moving train and track beam bridges,which are directly established by using finite element method.The model is proven to be applicable by comparing with Monte Carlo simulation.By applying the proposed stochastic framework to the high maglev line,the random dynamic responses of maglev vehicles running on the bridges are studied for running safety and stability assessment.Moreover,the effects of track irregularity wavelength range under different amplitude and running speeds on the coupled system are investigated.The results show that the augmentation of train speed will move backward the sensitive wavelength interval,and track irregularity amplitude influences the response remarkably in the sensitive interval.
文摘Dynamic running law of the hydraulic driving system decides the hoisting cage velocity curve in a hoisting cycle and is decided by the characteristic of the hydraulic driving system and by the operating speed of hoist driver. The paper studies the dynamic running law of hydraulic driving system, analyses the influence of driver operating speed on the dynamic running characteristic, and points out the reasonable driver operating speed to control the dynamic stress in rope and to reduce the oscillation of rope system.
基金Supported by the National Hi-tech Research and Development Program of China(2007AA04Z415)the Hunan Province and Xiangtan City Natural Science Joint Foundation(09JJ8005)the Torch Program Project of Hunan Province(2008SH044)
文摘An integrated monitoring system for running parameters of key mining equipmenton the basis of condition monitoring technology and modern communication networktechnology was developed.The system consists of a client computer with functions ofsignal acquisition and processing, and a host computer in the central control room.Thesignal acquisition module of the client computer can collect the running parameters fromvarious monitoring terminals in real-time.The DSP high-speed data processing system ofthe main control module can quickly achieve the numerical calculation for the collectedsignal.The signal modulation and signal demodulation are completed by the frequencyshift keying circuit and phase-locked loop frequency circuit, respectively.Finally, the signalis sent to the host computer for logic estimation and diagnostic analysis using the networkcommunication technology, which is helpful for technicians and managers to control therunning state of equipment.
基金supported by the NIH (R01NS103481, R01NS111776, and R01NS131489)Indiana Department of Health (ISDH58180)(all to WW)。
文摘Spinal cord injury necessitates effective rehabilitation strategies, with exercise therapies showing promise in promoting recovery. This study investigated the impact of rehabilitation exercise on functional recovery and morphological changes following thoracic contusive spinal cord injury. After a 7-day recovery period after spinal cord injury, mice were assigned to either a trained group(10 weeks of voluntary running wheel or forced treadmill exercise) or an untrained group. Bi-weekly assessments revealed that the exercise-trained group, particularly the voluntary wheel exercise subgroup, displayed significantly improved locomotor recovery, more plasticity of dopaminergic and serotonin modulation compared with the untrained group. Additionally, exercise interventions led to gait pattern restoration and enhanced transcranial magnetic motor-evoked potentials. Despite consistent injury areas across groups, exercise training promoted terminal innervation of descending axons. In summary, voluntary wheel exercise shows promise for enhancing outcomes after thoracic contusive spinal cord injury, emphasizing the role of exercise modality in promoting recovery and morphological changes in spinal cord injuries. Our findings will influence future strategies for rehabilitation exercises, restoring functional movement after spinal cord injury.
基金The authors would like to acknowledge Jordyn Vienneau,Aimee(Smith)Mears,Christian Meyer,and Antonio Blago for their support in collecting data for this study.The authors would like to thank Adidas(Herzogenaurach,Germany)for providing the test shoes.
文摘Purpose This study aimed to investigate whether there is a systematic change of leg muscle activity,as quantified by surface electromyography(EMG),throughout a standard running footwear assessment protocol at a predetermined running speed.Methods Thirty-one physically active adults(15 females and 16 males)completed 5 testing rounds consisting of overground running trials at a speed of 3.5 m/s.The level of muscle activity from 6 major leg muscles was recorded using surface EMG.The variables assessed were the EMG total intensity as a function of time and the cumulative EMG overall intensity.Systematic effects of the chronological testing round(independent variable)on the normalized EMG overall intensity(dependent variable)were examined using Friedman analysis of variates and post hoc pairwise Wilcoxon signed-rank tests(α=0.05).Results There was a systematic reduction in overall EMG intensity for all 6 muscles over the time course of the running protocol(p<0.001)until the fourth testing round when EMG intensities reached a steady state.The one exception was the biceps femoris muscle,which showed a significant reduction of EMG intensity during the stance phase(p<0.001)but not the swing phase(p=0.16).Conclusion While running at a predetermined speed,the neuromuscular system undergoes an adaptation process characterized by a progressive reduction in the activity level of major leg muscles.This process may represent an optimization strategy of the neuromuscular system towards a more energetically efficient running style.Future running protocols should include a familiarization period of at least 7 min or 600 strides of running at the predetermined speed.
文摘Helicopter blade running elevation measurement is an important measure target in helicopter blade dynamic balance experimentation. The elevation influences the helicopter＇ s security and other performance capabilities. In testing, however, it has been difficult to measure the elevation when the rotor reaches high speeds. To get a simple, fast and highly accurate measurement system, photo electricity technology was applied to measuring the blade running elevation. Discussed is the measurement principle of blade running elevation, tire design of the measurement system and analysis of the measurement precision.
文摘Since the fi rst cases of coronavirus disease 2019(COVID-19)caused by severe acute respiratory syndrome coro-navirus 2(SARS-CoV-2)were reported at the end of 2019,this infection has spread around the globe,becoming a pandemic.The use of face masks and respirators is an important public health measure to reduce or prevent transmission of SARS-CoV-2.Here we discuss the hypothetical mechanisms by which exercise with face masks or respirators can induce detrimental effects on the cardiovascular system,potentially explaining adverse events such as cardiac arrhythmias and spontaneous pneumothorax.Although sudden death associated with the wearing of a face mask during running is a rare event,the risk is higher especially in those with existing cardiac comorbidities.In such cases,a mask designed specifi cally for runners with no or few side effects of oxygen defi ciency should be considered instead.
基金National Natural Science Foundation of China,No.42171455The Hong Kong RGC Research Impact Fund,No.R5011-23The Hong Kong General Research Fund,No.15204121。
文摘Urban environments offer a wealth of opportunities for residents to respite from their hectic life.Outdoor running or jogging becomes increasingly popular of an option.Impacts of urban environments on outdoor running,despite some initial studies,remain underexplored.This study aims to establish an analytical framework that can holistically assess the urban environment on the healthy vitality of running.The proposed framework is applied to two modern Chinese cities,i.e.,Guangzhou and Shenzhen.We construct three interpretable random forest models to explore the non-linear relationship between environmental variables and running intensity(RI)through analyzing the runners'trajectories and integrating with multi-source urban big data(e.g.,street view imagery,remote sensing,and socio-economic data)across the built,natural,and social dimensions,The findings uncover that road density has the greatest impact on RI,and social variables(e.g.,population density and housing price)and natural variables(e.g.,slope and humidity)all make notable impact on outdoor running.Despite these findings,the impact of environmental variables likely change across different regions due to disparate regional construction and micro-environments,and those specific impacts as well as optimal thresholds also alter.Therefore,construction of healthy cities should take the whole urban environment into account and adapt to local conditions.This study provides a comprehensive evaluation on the influencing variables of healthy vitality and guides sustainable urban planning for creating running-friendly cities.
文摘BACKGROUND Wound management is an essential part of emergency medicine practice.A good suture technique should deal a complex irregular traumatic wound without any complications of dehiscence/gaping,infection,delayed wound healing,frequent dressings and further stay in hospital.There is no ideal technique of suturing for any wound.In pursuit of the new techniques,we have introduced a new suturing technique called combined oblique and vertical everting running(COVER)stitch which has showed good healing with less complications.AIM To compare the outcomes between the COVER stitch and conventional suturing group.METHODS In this study,we included 40 cases which were divided into two groups.Group 1 patients were managed by COVER stitch,and group 2 patients underwent conventional suturing for their wounds.The outcomes were measured in terms of scar quality,suturing duration and length of suture material used,suturing related complications and suture removal time which were compared by t-test usingχ^(2) test.RESULTS Better results were seen in COVER stitch than the conventional suturing.COVER group had significantly better results in terms of time taken for suture,amount suture material used and time taken for suture removal compared to the conventional group.No wound related complications were seen in this group.Moreover,scar formed was also better in COVER group.CONCLUSION COVER stitch is another new technique which can be used to deal simple to complex wounds and it is an emerging idea with good healthy scars with less complications.
文摘Poplars and the Gobi,camels and the desert,mulberry trees and the Silk Road,yaks and the snowcapped mountains,even the monkshood with its lovely but poisonous blossoms once used by hunters,and the mythical Cordyceps sinensis,a creature that is grass in summer and worm in winter.These plants and animals,wrapped in legend and story,have long captured the imagination.They are the emblematic life forms of China’s vast western lands.
基金Project(52078501)supported by the National Natural Science Foundation of ChinaProject(2022-Major-14)supported by the Science and Technology Research and Development Program Project of China Railway Group LimitedProject(2023ZZTS0342)supported by the Fundamental Research Funds for the Central Universities,China。
文摘Subgrade settlement is a common issue in soil ground within earthquake-prone regions,posing a threat to the safe operation of train-slab track coupled system(TSCS)in high-speed railways(HSRs).This study aims to analyze the mechanical behavior evolution of TSCS under subgrade settlement and earthquake excitation.The refined numerical model of slab track under subgrade differential settlement is established.The short settlement wavelength of 10 m causes the separation between the base and subgrade.The dynamic model of TSCS under subgrade settlement and earthquake excitation is developed.The dynamic response of TSCS exhibits more pronounced fluctuations under the combined effects of subgrade settlement and earthquake excitation than under the effects of settlement or earthquake alone.The evaluation indexes for the running safety of train on slab track under different settlement wavelengths exhibit varying degrees of increase with settlement amplitude and are particularly sensitive to the short settlement wavelength of 10 m.The wheel unloading rate and derailment coefficient of TSCS increase with earthquake intensity.Under the settlement wavelength of 10 m and amplitude of 20 mm,the wheel unloading rate of TSCS exceeds the allowable limit when the earthquake intensity exceeds 0.17g,and the derailment coefficient exceeds the allowable limit when the earthquake intensity surpasses 0.29g.
基金The National Key Technology R&D Program of China during the 11th Five-Year Plan Period(No.2006BAH02A06)
文摘A real-life milk run system designing problem of an engine manufacturer adopted JIT(just-in-time)production is studied.In the process of milk run system planning and design,the supply base is identified and a supplier site map is plotted for an arrangement of routes on which parts are periodically collected in a JIT manner from many scattered suppliers.With unit load designing,vehicle choosing and fleet sizing,pickup routing,vehicle assigning and scheduling problems are studied.Among these problems,a CVRP problem is identified and formulated as the key optimization in designing this milk run system,and it is solved through an optimization process.This tactical planning and optimization process gives a good solution to the real problem,and may shed light on the planning of similar systems.
基金Supported by National Natural Science Fund(70861004)~~
文摘According to the characteristics of circular agricultural mode focusing on pig farming and by dint of system dynamics mode-based analysis techniques to analyze the characteristics,the operation force for the recycling agricultural system focusing on pig farming was put forward.
