We present the numerical analysis of a coupled method for the numerical simulation of transient viscoelastic flow obeying a differential constitutive equation with a Newtonian viscosity. The scheme used is based on Eu...We present the numerical analysis of a coupled method for the numerical simulation of transient viscoelastic flow obeying a differential constitutive equation with a Newtonian viscosity. The scheme used is based on Euler implicit method in time and maintains at each time step a couple of the velocity u and the viscoelastic part of the stress σ. Approximation in space is made by finite element method. The approximate stress, velocity and pressure are, respectively, P1-continuous, p2-continuous, and p1continuous. Upwinding needed for convection of σ is made by a 'Streamline Upwind Petrov Galerkin' method (SUPG).展开更多
Wind power has made rapid progress and should gain significance as an energy resource,given growing interest in renewable energy and clean energy.Offshore wind energy resources have attracted significant attention,as,...Wind power has made rapid progress and should gain significance as an energy resource,given growing interest in renewable energy and clean energy.Offshore wind energy resources have attracted significant attention,as,compared with land-based wind energy resources,offshore wind energy resources are more promising candidates for development.Sea winds are generally stronger and more reliable and with improvements in technology,the sea has become a hot spot for new designs and installation methods for wind turbines.In the present paper,based on experience building offshore wind farms,recommended foundation styles have been examined.Furthermore,wave effects have been investigated.The split installation and overall installation have been illustrated.Methods appropriate when installing a small number of turbines as well as those useful when installing large numbers of turbines were analyzed.This investigation of installation methods for wind turbines should provide practical technical guidance for their installation.展开更多
The study discusses accuracy evaluation methods for offshore wind energy resources by using scatterometer SeaWinds-derived wind speed and Weibull parameters. The purpose of this study is to evaluate accuracies of SeaW...The study discusses accuracy evaluation methods for offshore wind energy resources by using scatterometer SeaWinds-derived wind speed and Weibull parameters. The purpose of this study is to evaluate accuracies of SeaWinds-derived Weibull mean wind speed and energy density by considering uncertainties inherent in SeaWinds wind speed estimates. In this study, 1159 SeaWinds-derived wind speeds covering the KEO buoy are used for estimating two Weibull parameters, scale and shape. On the other hand, observed wind speeds from 2004 to 2008 at the KEO buoy are used for simulating three kinds of wind speeds in order to quantify some uncertainties inherent in SeaWinds-derived wind speeds. It is found that uncertainties associated with wind speed estimates （operational wind speed range, sampling time） show small differences in scale, shape and Weibull mean wind speed except energy density among the simulated datasets. Furthermore, the upper and lower bounds of 90% confidence interval corresponding to SeaWinds number of observations indicate 4-2.5% error of Weibull mean wind speed and 4-6.8% error of energy density, respectively.展开更多
In this paper a new methodological approach, life cycle cost assessment （LCCA）, is applied to evaluate the investment concerning a wind offshore plant location in Sicily East Coast. In particular, we analyze economi...In this paper a new methodological approach, life cycle cost assessment （LCCA）, is applied to evaluate the investment concerning a wind offshore plant location in Sicily East Coast. In particular, we analyze economic quantification of the damage deriving from the construction of the system, divided into environmental impacts deriving from the construction of a single turbine, and environmental impacts as a consequence of the construction of the foundations. The preliminary economic information for the LCCA analysis of the examined wind park offshore regards the management of the monetary capital initially invested, choice of the interest rate and of other necessary financial features, used to compute the net present value of the cash-flows accrued during the project lifetime. In this way, a more precise implementation of the LCCA in whatever type of structural investment is made possible, allowing the examination of all information useful for supporting the decision process.展开更多
Increasing size of wind turbine and deep water deployment have raised the issue of appropriate selection of the most suitable support structure to make offshore wind energy cost competitive.The paper presents an optim...Increasing size of wind turbine and deep water deployment have raised the issue of appropriate selection of the most suitable support structure to make offshore wind energy cost competitive.The paper presents an optimization methodology for decision making process of bottom mounted supports of offshore wind turbines （OWTs） through reasonable engineering attributes derivation.Mathematic models of support structures are reduced by the generalized single-degree-of-freedom theory with relatively fewer structural parameters.Soft-stiff design optimization based on dynamic properties of OWTs is performed for monopile and lattice supports with different wind turbines,water depth and hub height.Attributes of support structures,wind turbines and environment conditions are applied in the multi-criteria decision making method——TOPSIS for benchmarking of those options.The results illustrate the effectiveness of the proposed optimazation methodology combined with economical and environmental attributes together.展开更多
Objective To explore the effect of meridian sinew row needling combined with dermal needling on spasticity of post-stroke patients with upper limb hemiparalysis. Methods Four hundred and eighty-eight cases of post-str...Objective To explore the effect of meridian sinew row needling combined with dermal needling on spasticity of post-stroke patients with upper limb hemiparalysis. Methods Four hundred and eighty-eight cases of post-stroke patients with upper limb spasticity were randomly divided into two groups at the ratio of 1： 1, the group of meridian sinew row needling combined with dermal needling （group A, 244 cases） and western medication group （group B, 244 cases）. Coupled with rehabilitation, the patients in the group A were given meridian sinew row needling combined with dermal needling where five shu points were specifically selected, and three yang meridians of the hand were treated with acupuncture with muscle region, and three yin meridians of the hand were treated with dermal needles; the patients in the group B was treated with conventional western medication with piracetam injection and cerebroprotein hydrolysate included. Clinical efficacy was evaluated among patients in the two groups after three weeks of continuous treatment, and upper limb spasticity and motor functions were observed through modified Asworth Scale and FugI-Meyer Assessment Scale （FMA） before and after treatment. Results For Asworth Scale, group A was significantly superior to group B （3.04 ± 1.29 vs 3.88 ± 1.54, P〈0.05）; for FMA scale, group A was also significantly superior to group B （48.67± 15.64 vs 42.96±14.72, P〈0.05）; mitigations of motor status of upper limb joints in group A, such as remission of shoulder adduction （90.5%）, pronation of forearm （70.7%）, elbow joint flexion （73.1%）, wrist joint flexion （80.9%） and finger flexion （88.1%）, were superior to those of group B （70.0%, 60.0%, 61.9%, 57.4%, 63.2%, all P〈0.05）. Conclusion Good clinical efficacy of the treatment with combined with dermal needling on spasticity of post-stroke patients with upper limb hemiparalysis is achieved.展开更多
文摘We present the numerical analysis of a coupled method for the numerical simulation of transient viscoelastic flow obeying a differential constitutive equation with a Newtonian viscosity. The scheme used is based on Euler implicit method in time and maintains at each time step a couple of the velocity u and the viscoelastic part of the stress σ. Approximation in space is made by finite element method. The approximate stress, velocity and pressure are, respectively, P1-continuous, p2-continuous, and p1continuous. Upwinding needed for convection of σ is made by a 'Streamline Upwind Petrov Galerkin' method (SUPG).
基金Supported by 111 Project Foundation under Grant No.B07019the National Natural Science Foundation of China under Grand No.50979020
文摘Wind power has made rapid progress and should gain significance as an energy resource,given growing interest in renewable energy and clean energy.Offshore wind energy resources have attracted significant attention,as,compared with land-based wind energy resources,offshore wind energy resources are more promising candidates for development.Sea winds are generally stronger and more reliable and with improvements in technology,the sea has become a hot spot for new designs and installation methods for wind turbines.In the present paper,based on experience building offshore wind farms,recommended foundation styles have been examined.Furthermore,wave effects have been investigated.The split installation and overall installation have been illustrated.Methods appropriate when installing a small number of turbines as well as those useful when installing large numbers of turbines were analyzed.This investigation of installation methods for wind turbines should provide practical technical guidance for their installation.
文摘The study discusses accuracy evaluation methods for offshore wind energy resources by using scatterometer SeaWinds-derived wind speed and Weibull parameters. The purpose of this study is to evaluate accuracies of SeaWinds-derived Weibull mean wind speed and energy density by considering uncertainties inherent in SeaWinds wind speed estimates. In this study, 1159 SeaWinds-derived wind speeds covering the KEO buoy are used for estimating two Weibull parameters, scale and shape. On the other hand, observed wind speeds from 2004 to 2008 at the KEO buoy are used for simulating three kinds of wind speeds in order to quantify some uncertainties inherent in SeaWinds-derived wind speeds. It is found that uncertainties associated with wind speed estimates （operational wind speed range, sampling time） show small differences in scale, shape and Weibull mean wind speed except energy density among the simulated datasets. Furthermore, the upper and lower bounds of 90% confidence interval corresponding to SeaWinds number of observations indicate 4-2.5% error of Weibull mean wind speed and 4-6.8% error of energy density, respectively.
文摘In this paper a new methodological approach, life cycle cost assessment （LCCA）, is applied to evaluate the investment concerning a wind offshore plant location in Sicily East Coast. In particular, we analyze economic quantification of the damage deriving from the construction of the system, divided into environmental impacts deriving from the construction of a single turbine, and environmental impacts as a consequence of the construction of the foundations. The preliminary economic information for the LCCA analysis of the examined wind park offshore regards the management of the monetary capital initially invested, choice of the interest rate and of other necessary financial features, used to compute the net present value of the cash-flows accrued during the project lifetime. In this way, a more precise implementation of the LCCA in whatever type of structural investment is made possible, allowing the examination of all information useful for supporting the decision process.
基金Supported by the National Natural Science Foundation of China （No.51309209,51279186） and the National Basic Research Program of China （No.2011CB013704）.
文摘Increasing size of wind turbine and deep water deployment have raised the issue of appropriate selection of the most suitable support structure to make offshore wind energy cost competitive.The paper presents an optimization methodology for decision making process of bottom mounted supports of offshore wind turbines （OWTs） through reasonable engineering attributes derivation.Mathematic models of support structures are reduced by the generalized single-degree-of-freedom theory with relatively fewer structural parameters.Soft-stiff design optimization based on dynamic properties of OWTs is performed for monopile and lattice supports with different wind turbines,water depth and hub height.Attributes of support structures,wind turbines and environment conditions are applied in the multi-criteria decision making method——TOPSIS for benchmarking of those options.The results illustrate the effectiveness of the proposed optimazation methodology combined with economical and environmental attributes together.
基金Supported by Hebei Administration of Traditional Chinese Medicine(2009180)
文摘Objective To explore the effect of meridian sinew row needling combined with dermal needling on spasticity of post-stroke patients with upper limb hemiparalysis. Methods Four hundred and eighty-eight cases of post-stroke patients with upper limb spasticity were randomly divided into two groups at the ratio of 1： 1, the group of meridian sinew row needling combined with dermal needling （group A, 244 cases） and western medication group （group B, 244 cases）. Coupled with rehabilitation, the patients in the group A were given meridian sinew row needling combined with dermal needling where five shu points were specifically selected, and three yang meridians of the hand were treated with acupuncture with muscle region, and three yin meridians of the hand were treated with dermal needles; the patients in the group B was treated with conventional western medication with piracetam injection and cerebroprotein hydrolysate included. Clinical efficacy was evaluated among patients in the two groups after three weeks of continuous treatment, and upper limb spasticity and motor functions were observed through modified Asworth Scale and FugI-Meyer Assessment Scale （FMA） before and after treatment. Results For Asworth Scale, group A was significantly superior to group B （3.04 ± 1.29 vs 3.88 ± 1.54, P〈0.05）; for FMA scale, group A was also significantly superior to group B （48.67± 15.64 vs 42.96±14.72, P〈0.05）; mitigations of motor status of upper limb joints in group A, such as remission of shoulder adduction （90.5%）, pronation of forearm （70.7%）, elbow joint flexion （73.1%）, wrist joint flexion （80.9%） and finger flexion （88.1%）, were superior to those of group B （70.0%, 60.0%, 61.9%, 57.4%, 63.2%, all P〈0.05）. Conclusion Good clinical efficacy of the treatment with combined with dermal needling on spasticity of post-stroke patients with upper limb hemiparalysis is achieved.
