Eddy current dampers (ECDs) have emerged as highly desirable solutions for vibration control due to theirexceptional damping performance and durability. However, the existing constitutive models present challenges tot...Eddy current dampers (ECDs) have emerged as highly desirable solutions for vibration control due to theirexceptional damping performance and durability. However, the existing constitutive models present challenges tothe widespread implementation of ECD technology, and there is limited availability of finite element analysis (FEA)software capable of accurately modeling the behavior of ECDs. This study addresses these issues by developing anewconstitutivemodel that is both easily understandable and user-friendly for FEAsoftware. By utilizing numericalresults obtained from electromagnetic FEA, a novel power law constitutive model is proposed to capture thenonlinear behavior of ECDs. The effectiveness of the power law constitutive model is validated throughmechanicalproperty tests and numerical seismic analysis. Furthermore, a detailed description of the application process ofthe power law constitutive model in ANSYS FEA software is provided. To facilitate the preliminary design ofECDs, an analytical derivation of energy dissipation and parameter optimization for ECDs under harmonicmotionis performed. The results demonstrate that the power law constitutive model serves as a viable alternative forconducting dynamic analysis using FEA and optimizing parameters for ECDs.展开更多
Spatial heterogeneity and stability are fundamental indices for describing vegetation communities. The spatial distribution characteristics of the vegetation in Nenjiang region of northeastern China were evaluated usi...Spatial heterogeneity and stability are fundamental indices for describing vegetation communities. The spatial distribution characteristics of the vegetation in Nenjiang region of northeastern China were evaluated using a variance power-law model. The data fits the model well with estimates given for the levels of heterogeneity for not only single species but also the community as a whole. The linear regression indicates that the species in the community exhibit a consistently organized spatial pattern, as is often discovered in field surveys but rarely seen in artificial systems. The species deviations from the regression line, which exhibit a leptokurtic distribution, may reflect the variability of the community. Thus, the model provides a general tool for management and regulation of ecosystems, especially where there is human disturbances.展开更多
According to the macromarket law, the total supply will go to equilibrium with the total demand for the world as a whole. Textiles are consumables, the total demand of which must be proportional to the population. For...According to the macromarket law, the total supply will go to equilibrium with the total demand for the world as a whole. Textiles are consumables, the total demand of which must be proportional to the population. For any large district, the share ratio - the ratio of the local productivity world share to the local population world share,will approach unity in long term period. The uncommon prosperity of the textile industry in the developed countries before the Second World War had been established by super economical means of the old era. The developing countries nowadays have no such means, and will never be able to establish the local textile Industry to an uncommon large scale. The development model of the textile industry must be in four stages: the first two are common both for the developed and for the developing countries, namely demand leading - supply leading. The third stage is quite different: uncommon expansion followed by significant declination, for the developed, and the re -展开更多
In this article, a law of iterated logarithm for the maximum likelihood estimator in a random censoring model with incomplete information under certain regular conditions is obtained.
In this paper, analysis of post-treatment of wire coating is presented. Coating material satisfies power law fluid model. Exact solutions for the velocity field, volume flow rate and average velocity are obtained. Mor...In this paper, analysis of post-treatment of wire coating is presented. Coating material satisfies power law fluid model. Exact solutions for the velocity field, volume flow rate and average velocity are obtained. Moreover, the heat transfer results are presented for different cases of linearly varying on the boundaries. The variations of velocity, volume flow rate, radius of coated wire, shear rate and the force on the total wire are presented graphically and discussed.展开更多
The Francis turbine governing system models in PSD-BPA can’t precisely reflect the actual characteristics. Endeavor was done in this paper to solve the problem. An improved model of actuating mechanism was developed,...The Francis turbine governing system models in PSD-BPA can’t precisely reflect the actual characteristics. Endeavor was done in this paper to solve the problem. An improved model of actuating mechanism was developed, which could reflect the step closing characteristic of hydro guide vanes. The effect of the inflection point value of actuating mechanism on load rejection was analyzed based on simulation. The non-linear Francis turbine model with power versus gate position module was researched in this paper. Based on field test, comparisons of simulation results with measured data were presented. The analysis demonstrates that the improved models of Francis turbine and governor proposed in this paper are more realistic than the models of BPA, and can be applied in power system simulation analysis better.展开更多
To study the similitude laws for dynamic ice force model test which is a hot problem in ice mechanics.In this paper,a new modified similitude law for dynamic ice force model test is proposed based on ice-induced virbr...To study the similitude laws for dynamic ice force model test which is a hot problem in ice mechanics.In this paper,a new modified similitude law for dynamic ice force model test is proposed based on ice-induced virbration theory and two reasonable assumptions.And the new law is vertified with an ice-induced pier virbration example.The numerical calculation results show that,firstly,the error of frequency factor between test value and theory value is small as well as that of displacement and velocity;Secondly,the time scale completely meet the similitude relation,the waveforms anastomotic well,and the phenomenon of offset and omit do not occur;Thirdly,as the damping ratio between prototype and model is nearly equal,the improved similitude law will still be applied.Therefore,the new modified similitude law is feasible to study dynamic ice force model test and can provide reference for the ice mechanics.展开更多
Wet compression is an effective way to enhance the performance of gas turbines and it has attracted a good deal of attention in recent years. The one sidedness and inaccuracy of previous studies,which took concentrati...Wet compression is an effective way to enhance the performance of gas turbines and it has attracted a good deal of attention in recent years. The one sidedness and inaccuracy of previous studies,which took concentration gradient as mass transfer potential are discussed. The mass transfer process is analyzed from the viewpoint of non equilibrium thermodynamics,by taking generalized thermodynamic driving force as mass transfer potential,and the corresponding mass transfer coefficient is obtained using the heat and mass transfer equilibrium occurring between moist air and water droplets at wet bulb temperature for the sake of avoiding complex tests and providing more accurate formulas. A mathematical model of wet compression is therefore established,and the general laws of wet compression are investigated. The results show that the performance of atomizer is critical for wet compression and wet compression is more suitable for compressors with higher pressure ratio and longer compression time.展开更多
This paper focuses on the Noether symmetries and the conserved quantities for both holonomic and nonholonomic systems based on a new non-conservative dynamical model introduced by E1-Nabulsi. First, the E1-Nabulsi dyn...This paper focuses on the Noether symmetries and the conserved quantities for both holonomic and nonholonomic systems based on a new non-conservative dynamical model introduced by E1-Nabulsi. First, the E1-Nabulsi dynamical model which is based on a fractional integral extended by periodic laws is introduced, and E1-Nabulsi-Hamilton's canoni- cal equations for non-conservative Hamilton system with holonomic or nonholonomic constraints are established. Second, the definitions and criteria of E1-Nabulsi-Noether symmetrical transformations and quasi-symmetrical transformations are presented in terms of the invariance of E1-Nabulsi-Hamilton action under the infinitesimal transformations of the group. Fi- nally, Noether's theorems for the non-conservative Hamilton system under the E1-Nabulsi dynamical system are established, which reveal the relationship between the Noether symmetry and the conserved quantity of the system.展开更多
We select the per capita gross domestic product and rural residents' per capita net income in Xinjiang as the indicator variables to measure economic growth and farmers' income increase in Xinjiang, respective...We select the per capita gross domestic product and rural residents' per capita net income in Xinjiang as the indicator variables to measure economic growth and farmers' income increase in Xinjiang, respectively. We establish the cointegration equation, the vector error correction (VEC) model, and use the impulse response function to conduct empirical analysis of the evolutive law concerning relationship between economic growth and farmers' income increase in Xinjiang during the period 1978-2010. The results show that there is a cointegration relationship between economic growth in Xinjiang and farmers' income increase; the former plays an important role in promoting the latter, following the evolutive law "first intensify, then abate, intensify again, and finally become stable". We put the following policy recommendations: providing preferential policies for farmers, scientifically and rationally guiding the transfer of rural labor; improving the function of agriculture, increasing the proportion of non-farm income; gradually bridging the widening income gap between urban and rural areas, coordinating urban and rural development.展开更多
Simplified wave models- such as kinematic,diffusion and quasi-steady- are widely employed as a convenient replacement of the full dynamic one in the analysis of unsteady open-channel flows,and especially for flood rou...Simplified wave models- such as kinematic,diffusion and quasi-steady- are widely employed as a convenient replacement of the full dynamic one in the analysis of unsteady open-channel flows,and especially for flood routing.While their use may guarantee a significant reduction of the computational effort,it is mandatory to define the conditions in which they may be confidently applied.The present paper investigates the applicability conditions of the kinematic,diffusion and quasisteady dynamic shallow wave models for mud flows of power-law fluids.The power-law model describes in an adequate and convenient way fluids that at low shear rates fluids do not posses yield stress,such as clay or kaolin suspensions,which are frequently encountered in Chinese rivers.In the framework of a linear analysis,the propagation characteristics of a periodic perturbation of an initial steady uniform flow predicted by the simplified models are compared with those of the full dynamic one.Based on this comparison,applicability criteria for the different wave approximations for mud flood of power-law fluids are derived.The presented results provide guidelines for selecting the appropriate approximation for a given flow problem,and therefore they may represent a useful tool for engineering predictions.展开更多
At present, the polymer solution is usually assumed to be Newtonian fluid or pseudoplastic fluid, and its elasticity is not considered on the study of polymer flooding well testing model. A large number of experiments...At present, the polymer solution is usually assumed to be Newtonian fluid or pseudoplastic fluid, and its elasticity is not considered on the study of polymer flooding well testing model. A large number of experiments have shown that polymer solutions have viscoelasticity, and disregarding the elasticity will cause certain errors in the analysis of polymer solution seepage law. Based on the percolation theory, this paper describes the polymer flooding mechanism from the two aspects of viscous effect and elastic effect, the mathematical model of oil water two-phase three components unsteady flow in viscoelastic polymer flooding was established, and solved by finite difference method, and the well-test curve was drawn to analyze the rule of well test curve in polymer flooding. The results show that, the degree of upward warping in the radial flow section of the pressure recovery curve when considering polymer elasticity is greater than the curve which not considering polymer elasticity. The relaxation time, power-law index, polymer injection concentration mainly affect the radial flow stage of the well testing curve. The relaxation time, power-law index, polymer injection concentration and other polymer flooding parameters mainly affect the radial flow stage of the well testing curve. The larger the polymer flooding parameters, the greater the degree of upwarping of the radial flow derivative curve. This model has important reference significance for well-testing research in polymer flooding oilfields.展开更多
文摘Eddy current dampers (ECDs) have emerged as highly desirable solutions for vibration control due to theirexceptional damping performance and durability. However, the existing constitutive models present challenges tothe widespread implementation of ECD technology, and there is limited availability of finite element analysis (FEA)software capable of accurately modeling the behavior of ECDs. This study addresses these issues by developing anewconstitutivemodel that is both easily understandable and user-friendly for FEAsoftware. By utilizing numericalresults obtained from electromagnetic FEA, a novel power law constitutive model is proposed to capture thenonlinear behavior of ECDs. The effectiveness of the power law constitutive model is validated throughmechanicalproperty tests and numerical seismic analysis. Furthermore, a detailed description of the application process ofthe power law constitutive model in ANSYS FEA software is provided. To facilitate the preliminary design ofECDs, an analytical derivation of energy dissipation and parameter optimization for ECDs under harmonicmotionis performed. The results demonstrate that the power law constitutive model serves as a viable alternative forconducting dynamic analysis using FEA and optimizing parameters for ECDs.
基金Supported by the Japan Society for the Promotion of Science (No. L-02711)
文摘Spatial heterogeneity and stability are fundamental indices for describing vegetation communities. The spatial distribution characteristics of the vegetation in Nenjiang region of northeastern China were evaluated using a variance power-law model. The data fits the model well with estimates given for the levels of heterogeneity for not only single species but also the community as a whole. The linear regression indicates that the species in the community exhibit a consistently organized spatial pattern, as is often discovered in field surveys but rarely seen in artificial systems. The species deviations from the regression line, which exhibit a leptokurtic distribution, may reflect the variability of the community. Thus, the model provides a general tool for management and regulation of ecosystems, especially where there is human disturbances.
文摘According to the macromarket law, the total supply will go to equilibrium with the total demand for the world as a whole. Textiles are consumables, the total demand of which must be proportional to the population. For any large district, the share ratio - the ratio of the local productivity world share to the local population world share,will approach unity in long term period. The uncommon prosperity of the textile industry in the developed countries before the Second World War had been established by super economical means of the old era. The developing countries nowadays have no such means, and will never be able to establish the local textile Industry to an uncommon large scale. The development model of the textile industry must be in four stages: the first two are common both for the developed and for the developing countries, namely demand leading - supply leading. The third stage is quite different: uncommon expansion followed by significant declination, for the developed, and the re -
文摘In this article, a law of iterated logarithm for the maximum likelihood estimator in a random censoring model with incomplete information under certain regular conditions is obtained.
文摘In this paper, analysis of post-treatment of wire coating is presented. Coating material satisfies power law fluid model. Exact solutions for the velocity field, volume flow rate and average velocity are obtained. Moreover, the heat transfer results are presented for different cases of linearly varying on the boundaries. The variations of velocity, volume flow rate, radius of coated wire, shear rate and the force on the total wire are presented graphically and discussed.
文摘The Francis turbine governing system models in PSD-BPA can’t precisely reflect the actual characteristics. Endeavor was done in this paper to solve the problem. An improved model of actuating mechanism was developed, which could reflect the step closing characteristic of hydro guide vanes. The effect of the inflection point value of actuating mechanism on load rejection was analyzed based on simulation. The non-linear Francis turbine model with power versus gate position module was researched in this paper. Based on field test, comparisons of simulation results with measured data were presented. The analysis demonstrates that the improved models of Francis turbine and governor proposed in this paper are more realistic than the models of BPA, and can be applied in power system simulation analysis better.
基金Sponsored by the National Natural Science Foundation of China(Grant No.50678033)
文摘To study the similitude laws for dynamic ice force model test which is a hot problem in ice mechanics.In this paper,a new modified similitude law for dynamic ice force model test is proposed based on ice-induced virbration theory and two reasonable assumptions.And the new law is vertified with an ice-induced pier virbration example.The numerical calculation results show that,firstly,the error of frequency factor between test value and theory value is small as well as that of displacement and velocity;Secondly,the time scale completely meet the similitude relation,the waveforms anastomotic well,and the phenomenon of offset and omit do not occur;Thirdly,as the damping ratio between prototype and model is nearly equal,the improved similitude law will still be applied.Therefore,the new modified similitude law is feasible to study dynamic ice force model test and can provide reference for the ice mechanics.
文摘Wet compression is an effective way to enhance the performance of gas turbines and it has attracted a good deal of attention in recent years. The one sidedness and inaccuracy of previous studies,which took concentration gradient as mass transfer potential are discussed. The mass transfer process is analyzed from the viewpoint of non equilibrium thermodynamics,by taking generalized thermodynamic driving force as mass transfer potential,and the corresponding mass transfer coefficient is obtained using the heat and mass transfer equilibrium occurring between moist air and water droplets at wet bulb temperature for the sake of avoiding complex tests and providing more accurate formulas. A mathematical model of wet compression is therefore established,and the general laws of wet compression are investigated. The results show that the performance of atomizer is critical for wet compression and wet compression is more suitable for compressors with higher pressure ratio and longer compression time.
基金supported by the National Natural Science Foundation of China(Grant Nos.10972151 and 11272227)the Innovation Program for Postgraduate in Higher Education Institutions of Jiangsu Province,China(Grant No.CXLX11_0961)
文摘This paper focuses on the Noether symmetries and the conserved quantities for both holonomic and nonholonomic systems based on a new non-conservative dynamical model introduced by E1-Nabulsi. First, the E1-Nabulsi dynamical model which is based on a fractional integral extended by periodic laws is introduced, and E1-Nabulsi-Hamilton's canoni- cal equations for non-conservative Hamilton system with holonomic or nonholonomic constraints are established. Second, the definitions and criteria of E1-Nabulsi-Noether symmetrical transformations and quasi-symmetrical transformations are presented in terms of the invariance of E1-Nabulsi-Hamilton action under the infinitesimal transformations of the group. Fi- nally, Noether's theorems for the non-conservative Hamilton system under the E1-Nabulsi dynamical system are established, which reveal the relationship between the Noether symmetry and the conserved quantity of the system.
基金Supported by Soft Science Project of Science and Technology Department of Xinjiang Uygur Autonomous Region (200942140)
文摘We select the per capita gross domestic product and rural residents' per capita net income in Xinjiang as the indicator variables to measure economic growth and farmers' income increase in Xinjiang, respectively. We establish the cointegration equation, the vector error correction (VEC) model, and use the impulse response function to conduct empirical analysis of the evolutive law concerning relationship between economic growth and farmers' income increase in Xinjiang during the period 1978-2010. The results show that there is a cointegration relationship between economic growth in Xinjiang and farmers' income increase; the former plays an important role in promoting the latter, following the evolutive law "first intensify, then abate, intensify again, and finally become stable". We put the following policy recommendations: providing preferential policies for farmers, scientifically and rationally guiding the transfer of rural labor; improving the function of agriculture, increasing the proportion of non-farm income; gradually bridging the widening income gap between urban and rural areas, coordinating urban and rural development.
文摘Simplified wave models- such as kinematic,diffusion and quasi-steady- are widely employed as a convenient replacement of the full dynamic one in the analysis of unsteady open-channel flows,and especially for flood routing.While their use may guarantee a significant reduction of the computational effort,it is mandatory to define the conditions in which they may be confidently applied.The present paper investigates the applicability conditions of the kinematic,diffusion and quasisteady dynamic shallow wave models for mud flows of power-law fluids.The power-law model describes in an adequate and convenient way fluids that at low shear rates fluids do not posses yield stress,such as clay or kaolin suspensions,which are frequently encountered in Chinese rivers.In the framework of a linear analysis,the propagation characteristics of a periodic perturbation of an initial steady uniform flow predicted by the simplified models are compared with those of the full dynamic one.Based on this comparison,applicability criteria for the different wave approximations for mud flood of power-law fluids are derived.The presented results provide guidelines for selecting the appropriate approximation for a given flow problem,and therefore they may represent a useful tool for engineering predictions.
文摘At present, the polymer solution is usually assumed to be Newtonian fluid or pseudoplastic fluid, and its elasticity is not considered on the study of polymer flooding well testing model. A large number of experiments have shown that polymer solutions have viscoelasticity, and disregarding the elasticity will cause certain errors in the analysis of polymer solution seepage law. Based on the percolation theory, this paper describes the polymer flooding mechanism from the two aspects of viscous effect and elastic effect, the mathematical model of oil water two-phase three components unsteady flow in viscoelastic polymer flooding was established, and solved by finite difference method, and the well-test curve was drawn to analyze the rule of well test curve in polymer flooding. The results show that, the degree of upward warping in the radial flow section of the pressure recovery curve when considering polymer elasticity is greater than the curve which not considering polymer elasticity. The relaxation time, power-law index, polymer injection concentration mainly affect the radial flow stage of the well testing curve. The relaxation time, power-law index, polymer injection concentration and other polymer flooding parameters mainly affect the radial flow stage of the well testing curve. The larger the polymer flooding parameters, the greater the degree of upwarping of the radial flow derivative curve. This model has important reference significance for well-testing research in polymer flooding oilfields.