Background:Recently,Mullen et al.(2011)presented an 8-item version of the Physical Activity Enjoyment Scale(PACES)that provides a valid instrument for assessing enjoyment in physical activity.The present paper investi...Background:Recently,Mullen et al.(2011)presented an 8-item version of the Physical Activity Enjoyment Scale(PACES)that provides a valid instrument for assessing enjoyment in physical activity.The present paper investigated the psychometric properties of a Portuguese adaptation of PACES.Methods:After a process of back-to-back translation into Portuguese,395 members of fitness centers who ranged in age from 18 to 66 years(31.11§8.90,mean§SD)completed the translated version of the PACES.On average,participants had 3.2 years of experience in fitness group classes and practiced for approximately 3.3 times per week.Results:An initial exploratory factor analysis(n=139)revealed a unidimensional structure with factor loadings ranging from 0.79 to 0.89.Results also showed acceptable internal consistency.A confirmatory factor analysis in an independent sample(n=256)provided additional support for the unidimensional structure of the questionnaire.In addition,moderate positive correlations between enjoyment and intrinsic and identified regulation,and moderate negative correlations between enjoyment and external and amotivation,demonstrate the convergent validity of the instrument.Finally,measurement invariance between 2 independent samples was also found.Conclusion:The 8-item Portuguese version of PACES is a valid and reliable instrument for measuring enjoyment of physical activity in Portuguese adult fitness exercisers,and it is therefore suitable to use as a measure of affect in exercise adherence interventions studies.展开更多
Multi-layer pressure vessels are widely used in every field of high pressure technology.For the purpose of enhancing a vessels＇ load bearing capacity,a beneficial process like shrink-fit is usually employed.However,f...Multi-layer pressure vessels are widely used in every field of high pressure technology.For the purpose of enhancing a vessels＇ load bearing capacity,a beneficial process like shrink-fit is usually employed.However,few documents on optimum design for multi-layer shrink-fit vessels made of different strength materials can be found,available data are mainly on two-layer vessels.In this paper,an optimum design approach is developed for shrink-fit multi-layer vessels under ultrahigh pressure by using different materials.Maximum shear stress theory is applied as design criteria.The inner and outer radii of a multi-layer vessel,as well as the material of each layer,are assumed to be known.The optimization mathematical model is,thereby,built.Lagrange multipliers method is required to obtain the optimal design formula of wall ratio（ratio of outer to inner radii） of each layer,from which the optimum formulas of shrinkage pressure and radial interference are derived with the superposition principle employed.These formulas are applicable for the optimization design of all multi-layer vessels made of different materials,or same materials.The formulas of the limit working pressure and the contact pressure show that the optimum wall ratio of each layer and limit working pressure are only related to all selected material strength and unrelated to the position of the layer placement in the vessel.However,shrinkage pressure is related to the position of the layer placement in the vessel.Optimization design of an open ended shrink-fit three-layer vessel using different materials and comparisons proved that the optimized multi-layer vessels have outstanding characteristics of small radial interference and are easier for assembly.When the stress of each layer is distributed more evenly and appropriately,the load bearing capability and safety of vessels are enhanced.Therefore,this design is material-saving and cost-effective,and has prospect of engineering application.展开更多
This study discusses the application of the regulatory focus of the individual motivation systems to green public service advertisements advocating environmental protection. First, it aims to determine whether the pre...This study discusses the application of the regulatory focus of the individual motivation systems to green public service advertisements advocating environmental protection. First, it aims to determine whether the previously proposed regulatory fit theory can be applied to public service advertisements with characteristics different from those of commercial advertisements. Second, it aims to understand how to design messages to achieve the best effect on audiences with different foci. This study takes the regulatory focus theory as the basis and green public service advertisements as the films. After adopting 2 ~ 2 ~ 2 three-factor design to test the interaction relations among the individual regulatory focus, message regulatory focus, and message framing. The results from the 217 college respondents indicate that the audience is influenced by regulatory focus when receiving messages from public service advertisements, which is similar to the influence of commercial advertisements. That is, when audience with a promotion focus, films with promotion focus and positive framing have a best advertisement effect. On the other hand, the audience with a prevention focus, films with prevention focus and negative framing also has a better advertisement effect.展开更多
文摘Background:Recently,Mullen et al.(2011)presented an 8-item version of the Physical Activity Enjoyment Scale(PACES)that provides a valid instrument for assessing enjoyment in physical activity.The present paper investigated the psychometric properties of a Portuguese adaptation of PACES.Methods:After a process of back-to-back translation into Portuguese,395 members of fitness centers who ranged in age from 18 to 66 years(31.11§8.90,mean§SD)completed the translated version of the PACES.On average,participants had 3.2 years of experience in fitness group classes and practiced for approximately 3.3 times per week.Results:An initial exploratory factor analysis(n=139)revealed a unidimensional structure with factor loadings ranging from 0.79 to 0.89.Results also showed acceptable internal consistency.A confirmatory factor analysis in an independent sample(n=256)provided additional support for the unidimensional structure of the questionnaire.In addition,moderate positive correlations between enjoyment and intrinsic and identified regulation,and moderate negative correlations between enjoyment and external and amotivation,demonstrate the convergent validity of the instrument.Finally,measurement invariance between 2 independent samples was also found.Conclusion:The 8-item Portuguese version of PACES is a valid and reliable instrument for measuring enjoyment of physical activity in Portuguese adult fitness exercisers,and it is therefore suitable to use as a measure of affect in exercise adherence interventions studies.
基金supported by Key Scientific Research Project of Baoji University of Arts and Sciences of China (Grant No.ZK0727)Shanxi Provincial Special Foundation Project of Key Discipline Construction of China
文摘Multi-layer pressure vessels are widely used in every field of high pressure technology.For the purpose of enhancing a vessels＇ load bearing capacity,a beneficial process like shrink-fit is usually employed.However,few documents on optimum design for multi-layer shrink-fit vessels made of different strength materials can be found,available data are mainly on two-layer vessels.In this paper,an optimum design approach is developed for shrink-fit multi-layer vessels under ultrahigh pressure by using different materials.Maximum shear stress theory is applied as design criteria.The inner and outer radii of a multi-layer vessel,as well as the material of each layer,are assumed to be known.The optimization mathematical model is,thereby,built.Lagrange multipliers method is required to obtain the optimal design formula of wall ratio（ratio of outer to inner radii） of each layer,from which the optimum formulas of shrinkage pressure and radial interference are derived with the superposition principle employed.These formulas are applicable for the optimization design of all multi-layer vessels made of different materials,or same materials.The formulas of the limit working pressure and the contact pressure show that the optimum wall ratio of each layer and limit working pressure are only related to all selected material strength and unrelated to the position of the layer placement in the vessel.However,shrinkage pressure is related to the position of the layer placement in the vessel.Optimization design of an open ended shrink-fit three-layer vessel using different materials and comparisons proved that the optimized multi-layer vessels have outstanding characteristics of small radial interference and are easier for assembly.When the stress of each layer is distributed more evenly and appropriately,the load bearing capability and safety of vessels are enhanced.Therefore,this design is material-saving and cost-effective,and has prospect of engineering application.
文摘This study discusses the application of the regulatory focus of the individual motivation systems to green public service advertisements advocating environmental protection. First, it aims to determine whether the previously proposed regulatory fit theory can be applied to public service advertisements with characteristics different from those of commercial advertisements. Second, it aims to understand how to design messages to achieve the best effect on audiences with different foci. This study takes the regulatory focus theory as the basis and green public service advertisements as the films. After adopting 2 ~ 2 ~ 2 three-factor design to test the interaction relations among the individual regulatory focus, message regulatory focus, and message framing. The results from the 217 college respondents indicate that the audience is influenced by regulatory focus when receiving messages from public service advertisements, which is similar to the influence of commercial advertisements. That is, when audience with a promotion focus, films with promotion focus and positive framing have a best advertisement effect. On the other hand, the audience with a prevention focus, films with prevention focus and negative framing also has a better advertisement effect.
