Background： Physical activity （PA） includes muscle activity during exercise, manual work, and leisure time activities including sport. Conflicting results exist regarding health effects of PA that may deteriorate w...Background： Physical activity （PA） includes muscle activity during exercise, manual work, and leisure time activities including sport. Conflicting results exist regarding health effects of PA that may deteriorate with manual work and elite sports, but improve when performed in moderation in accordance with international guidelines and may additionally enhance well-being and productivity. Methods： In Denmark 15 randomized controlled trials have been conducted, introducing exercise at the workplace enrolling 〉3500 workers. The interventions lasted from 10 to 52 weeks and offered -1 h weekly supervised exercise during working hours according to the concept of intelligent physical exercise training （IPET） that is based on evidenced sports sciences training principles and tailored to work exposure, employee health status, and physical capacity. Questionnaire surveys and health checks including blood and muscle sampling were performed at baseline and follow-up. The job groups included： office and computer workers, dentists, industrial technicians, cleaning personnel, health care workers, construction workers, and fighter/helicopter pilots. Results： In all job groups significant improvements were documented regarding health outcomes. These were job group specific： neck pain was reduced among office and computer workers, dentists, industrial laboratory technicians, health care workers as well as fighter pilots. Cardio- respiratory fitness--a health risk indicator for cardio-metabolic diseases--was improved among office and computer workers, health care workers, and construction workers. Additionally, other improvements were evidenced such as increased muscle strength and balance control. Importantly, productivity increased with improved muscle strength and decreased body mass index. Conclusion： IPET does enhance health if an exercise program with evidenced efficacy is implemented by expert trainees with support of the employer. Accordingly, in every study group outcomes of improved health were documented and the effect sizes were of clinical relevance. Cost effectiveness estimates indicate acceptable cost relative to savings on health expenses and lost productivity.展开更多
Considering the effects of particle crushing and intermediate principal stress on material yielding strength, the spatial mobilization plane(SMP) yielding criterion and state parameter model including a general critic...Considering the effects of particle crushing and intermediate principal stress on material yielding strength, the spatial mobilization plane(SMP) yielding criterion and state parameter model including a general critical state line are selected in the analysis of cylindrical cavity expansion.Meanwhile, combining Rowe s flow rule and Bolton s simplification to stress-dilatancy relationship to reflect soil shear dilatancy and softening behavior, this paper analyzes the problem of cylindrical cavity expansion i...展开更多
The part 23 airworthiness standards for small airplanes states minimal standards of the emergency condition for the occupant protection. Under this regulation, the airplane must be designed and certified about static ...The part 23 airworthiness standards for small airplanes states minimal standards of the emergency condition for the occupant protection. Under this regulation, the airplane must be designed and certified about static strength of the fuselage and seats, horizontal and vertical dynamic strength of seats. Human injuries in dynamic crash tests and the survivability in the turnover condition should be also evaluated. The most important part among injuries of human is a head and the head injury is evaluated by Head Injury Criterion （HIC）. KC-100, 4 seats airplane that is manufactured by KAI, was conducted seat dynamic tests. The HIC from tests was well within criteria limits 1,000 and the occupant compartment for head protection provided hazard-free spaces in the occupant＇s head strike envelope for the frontal-horizontal crash impacts. The airplane also was conducted a turnover static test and analysis to especially show living spaces of the head. The airframe could sustain living spaces for occupants in the turnover condition and occupants could escape and be protected. The results of tests and analysis corresponded to the criteria and proved the retention of survivable space in emergency landing condition.展开更多
文摘Background： Physical activity （PA） includes muscle activity during exercise, manual work, and leisure time activities including sport. Conflicting results exist regarding health effects of PA that may deteriorate with manual work and elite sports, but improve when performed in moderation in accordance with international guidelines and may additionally enhance well-being and productivity. Methods： In Denmark 15 randomized controlled trials have been conducted, introducing exercise at the workplace enrolling 〉3500 workers. The interventions lasted from 10 to 52 weeks and offered -1 h weekly supervised exercise during working hours according to the concept of intelligent physical exercise training （IPET） that is based on evidenced sports sciences training principles and tailored to work exposure, employee health status, and physical capacity. Questionnaire surveys and health checks including blood and muscle sampling were performed at baseline and follow-up. The job groups included： office and computer workers, dentists, industrial technicians, cleaning personnel, health care workers, construction workers, and fighter/helicopter pilots. Results： In all job groups significant improvements were documented regarding health outcomes. These were job group specific： neck pain was reduced among office and computer workers, dentists, industrial laboratory technicians, health care workers as well as fighter pilots. Cardio- respiratory fitness--a health risk indicator for cardio-metabolic diseases--was improved among office and computer workers, health care workers, and construction workers. Additionally, other improvements were evidenced such as increased muscle strength and balance control. Importantly, productivity increased with improved muscle strength and decreased body mass index. Conclusion： IPET does enhance health if an exercise program with evidenced efficacy is implemented by expert trainees with support of the employer. Accordingly, in every study group outcomes of improved health were documented and the effect sizes were of clinical relevance. Cost effectiveness estimates indicate acceptable cost relative to savings on health expenses and lost productivity.
基金Supported by National Natural Science Foundation of China (No. 50639010)PhD Start-up Research Fund of Northeast Dianli University (2010)
文摘Considering the effects of particle crushing and intermediate principal stress on material yielding strength, the spatial mobilization plane(SMP) yielding criterion and state parameter model including a general critical state line are selected in the analysis of cylindrical cavity expansion.Meanwhile, combining Rowe s flow rule and Bolton s simplification to stress-dilatancy relationship to reflect soil shear dilatancy and softening behavior, this paper analyzes the problem of cylindrical cavity expansion i...
文摘The part 23 airworthiness standards for small airplanes states minimal standards of the emergency condition for the occupant protection. Under this regulation, the airplane must be designed and certified about static strength of the fuselage and seats, horizontal and vertical dynamic strength of seats. Human injuries in dynamic crash tests and the survivability in the turnover condition should be also evaluated. The most important part among injuries of human is a head and the head injury is evaluated by Head Injury Criterion （HIC）. KC-100, 4 seats airplane that is manufactured by KAI, was conducted seat dynamic tests. The HIC from tests was well within criteria limits 1,000 and the occupant compartment for head protection provided hazard-free spaces in the occupant＇s head strike envelope for the frontal-horizontal crash impacts. The airplane also was conducted a turnover static test and analysis to especially show living spaces of the head. The airframe could sustain living spaces for occupants in the turnover condition and occupants could escape and be protected. The results of tests and analysis corresponded to the criteria and proved the retention of survivable space in emergency landing condition.
