Conventional manipulators with rigid structures and sti ness actuators have poor flexibility,limited obstacle avoidance capability,and constrained workspace.Some developed flexible or soft manipulators in recent years...Conventional manipulators with rigid structures and sti ness actuators have poor flexibility,limited obstacle avoidance capability,and constrained workspace.Some developed flexible or soft manipulators in recent years have the characteristics of infinite degrees of freedom,high flexibility,environmental adaptability,and extended manipulation capability.However,these existing manipulators still cannot achieve the shrinking motion and independent control of specified segments like the animals,which hinders their applications.In this paper,a flexible bio-tensegrity manipulator,inspired by the longitudinal and transversal muscles of octopus tentacles,was proposed to mimic the shrinking behavior and achieve the variable motion patterns of each segment.Such proposed manipulator uses the elastic spring as the backbone,which is driven by four cables and has one variable structure mechanism in each segment to achieve the independent control of each segment.The variable structure mechanism innovatively contains seven lock-release states to independently control the bending and shrinking motion of each segment.After the kinematic modeling and analysis,one prototype of such bionic flexible manipulator was built and the open-loop control method was proposed.Some proof-of-concept experiments,including the shrinking motion,bending motion,and variable structure motion,were carried out by controlling the length of four cables and changing the lock-release states of the variable structure mechanism,which validate the feasibility and validity of our proposed prototype.Meanwhile,the experimental results show the flexible manipulator can accomplish the bending and shrinking motion with the relative error less than 6.8%through the simple independent control of each segment using the variable structure mechanism.This proposed manipulator has the features of controllable degree-of-freedom in each segment,which extend their environmental adaptability,and manipulation capability.展开更多
Modal parameter identification is a mature technology.However,there are some challenges in its practical applications such as the identification of vibration systems involving closely spaced modes and intensive noise ...Modal parameter identification is a mature technology.However,there are some challenges in its practical applications such as the identification of vibration systems involving closely spaced modes and intensive noise contamination.This paper proposes a new time-frequency method based on intrinsic chirp component decomposition(ICCD)to address these issues.In this method,a redundant Fourier model is used to ameliorate border distortions and improve the accuracy of signal reconstruction.The effectiveness and accuracy of the proposed method are illustrated using three examples:a cantilever beam structure with intensive noise contamination or environmental interference,a four-degree-of-freedom structure with two closely spaced modes,and an impact test on a cantilever rectangular plate.By comparison with the identification method based on the empirical wavelet transform(EWT),it is shown that the presented method is effective,even in a high-noise environment,and the dynamic characteristics of closely spaced modes are accurately determined.展开更多
This study investigates the impact of information communication technology(ICT),economic freedom,and economic sustainability on herding behavior,and examines whether the link between economic freedom and economic sust...This study investigates the impact of information communication technology(ICT),economic freedom,and economic sustainability on herding behavior,and examines whether the link between economic freedom and economic sustainability depends on ICT.Using quantile regression on a sample of seven Gulf Cooperation Council stock markets from 2004 to 2020,we find that ICT and economic freedom reduce herding in lower quantiles while promoting it in higher quantiles.Conversely,open market freedom and economic sustainability appear to correct herding in all quantiles.The results show that ICT reinforces the move away from herding seen with economic freedom for the transmission channel of ICT on herding.However,ICT plays a dual role in open market freedom and economic sustainability,weakening(strengthening)the curative effect of economic sustainability(open market freedom)in the lower quantiles and strengthening(weakening)it in higher quantiles.Thus,the highest impact in reducing herding exits through the combination of ICT and economic freedom is skewed to the lower quantiles with ICT-open market freedom and skewed to the upper quantiles with ICT-economic sustainability.These results offer substantial implications for policymakers.展开更多
The essence of academic freedom lies in scholars’autonomy in the pursuit of knowledge,free from external coercion and internal constraints,encompassing various aspects such as freedom of research,teaching,and learnin...The essence of academic freedom lies in scholars’autonomy in the pursuit of knowledge,free from external coercion and internal constraints,encompassing various aspects such as freedom of research,teaching,and learning.Leadership plays a crucial role in safeguarding academic freedom.Drawing on Macfarlane’s conceptualization of intellectual leadership,this article examines faculty-based agency protection,as well as institutional,cultural,and resource-based protections at the university level.展开更多
Padma was 17 when the democratic reform was introduced in Xizang in 1959.Before the reform,the region had been ruled by feudal serfdom under a theocracy for centuries.Nearly one million serfs were subjected to estate-...Padma was 17 when the democratic reform was introduced in Xizang in 1959.Before the reform,the region had been ruled by feudal serfdom under a theocracy for centuries.Nearly one million serfs were subjected to estate-holders'cruel exploitation and oppression.Padma was one of them.展开更多
The dynamic behavior of high-speed craft navigating through variable sea states plays a pivotal role in ensuring maritime safety.However,many existing simulation approaches rely on linear or overly simplified represen...The dynamic behavior of high-speed craft navigating through variable sea states plays a pivotal role in ensuring maritime safety.However,many existing simulation approaches rely on linear or overly simplified representations of the marine environment,thereby limiting the fidelity of motion predictions.This study explores the motion characteristics of a 4.5-t high-speed vessel by conducting fully coupled numerical simulations using the STAR-CCM+software.The analysis considers both calm and varying sea conditions,incorporating fluctuations in wave height,wavelength,and wind speed to reflect more realistic operating scenarios.Simulation results reveal that the vessel’s hydrodynamic response is highly sensitive to changes in sea state.As conditions deteriorate,the free surface becomes increasingly complex,with higher wave amplitudes and more pronounced interactions between the waves generated by the vessel and those imposed by the external environment.These effects lead to significant increases in roll,pitch,heave,and sway motions,thereby imposing greater demands on the vessel’s dynamic stability and operational safety.Furthermore,both hydrodynamic resistance and propulsive thrust exhibit notable dependence on sea state and vessel speed.Total resistance generally increases with rougher sea conditions,while thrust tends to rise with increasing forward speed.Under calm or mildly disturbed waters,a Froude number(Fr)of 0.5 appears to offer an optimal balance for initiating and controlling primary motions such as roll,pitch,heave,and sway.Conversely,in more challenging conditions-such as those represented by a Sea State 3-effective motion control is better achieved at a higher Froude number of approximately 1.0.展开更多
Objective:This study aimed to explore the effect of aromatherapy combined with emotional release technology on recurrence fear and sleep quality of lung cancer survivors.Methods:114 cases of lung cancer survivors were...Objective:This study aimed to explore the effect of aromatherapy combined with emotional release technology on recurrence fear and sleep quality of lung cancer survivors.Methods:114 cases of lung cancer survivors were divided into routine nursing group,emotional release technology group and aromatherapy combined with emotional release technology group.Routine nursing group received routine nursing;Emotional release technology group implemented emotional release technology for one month on the basis of routine nursing group;Aromatherapy combined with emotional release technology group used lavender aromatherapy on the basis of emotional release technology group.Results:After one month of intervention,there were statistically significant differences in the scores of fear of disease progression and sleep quality among the three groups.Conclusion:Aromatherapy combined with emotional release technology can improve the sleep quality of lung cancer survivors and reduce the economic toxicity of cancer to some extent.展开更多
“civil discourse”amongst multiple individuals with diverse viewpoints is necessary to move toward truth,to maintain democratic buoyancy,and to get the most accurate read on how best to move forward toward our collec...“civil discourse”amongst multiple individuals with diverse viewpoints is necessary to move toward truth,to maintain democratic buoyancy,and to get the most accurate read on how best to move forward toward our collective good,civil discourse is nonetheless under catastrophic threat by contemporary forces that include the sloppy use of the term“hate speech”;the“libelling by labeling”(aka“cancelling”)in the public square of social media;technologically powered disinformation campaigns;and the growth of“safetyism”in academia.In light of these threats,the goal must be to convince educators,particularly philosophical educators,of the need to adopt a whole new focus in education,namely one that puts a spotlight on the fact that the utilization of the freedom of speech to destroy the freedom of speech of others utterly undermines the positive value of freedom of speech.In order to motivate individuals to turn their back on the dopamine rush of shutting someone down,educators must also spend a great deal of time showcasing the merits of“civil discourse”by providing young people with extensive experience in engaging in facilitated“civil discourse”(aka Communities of Philosophical Inquiry)so that its value can be woven into a personal commitment.展开更多
The interaction between regular waves and an oscillating wave energy converter(WEC)in front of a vertical seawall is investigated using a 2D analytical model.A three-degree of freedom(DOF)WEC and a WEC hinged to the s...The interaction between regular waves and an oscillating wave energy converter(WEC)in front of a vertical seawall is investigated using a 2D analytical model.A three-degree of freedom(DOF)WEC and a WEC hinged to the seawall(constrained to pitch mode)are considered to examine the influence of the DOF of the WEC on the wave energy extraction performance.Results show that the piston-mode water resonance in the gap and the coupled WEC and water column resonant motion significantly influence the wave energy extraction efficiency.At low frequency,the case with a 3-DOF WEC has a broader high-efficiency bandwidth than that with a heaving WEC.However,3-DOF WEC exhibits worse performance at high frequencies.The frequency response of the wave energy capture width ratio(CWR)for the pitching WEC case shows a trimodal trend under the specified conditions.It showcases the best overall wave energy extraction performance in terms of the high-efficiency bandwidth.Furthermore,a parametric study indicates that the gap distance between the WEC and the seawall has tremendous effects on the CWR of both cases.As the position of the hinge point of the pitching WEC changes,the CWR at the low and high frequencies shows opposite trends.展开更多
This paper aims to evaluate the stochastic response of steel columns subjected to blast loads using the modified single degree of freedom(MSDOF)method,which assessed towards the conventional single degree of freedom(S...This paper aims to evaluate the stochastic response of steel columns subjected to blast loads using the modified single degree of freedom(MSDOF)method,which assessed towards the conventional single degree of freedom(SDOF)and the experimentally validated Finite Element(FE)methods(LSDYNA).For this purpose,special atten-tion is given to calculating the response of H-shaped steel columns under blast.The damage amount is determined based on the support rotation criterion,which is expressed as a function of their maximum lateral mid-span dis-placement.To account for uncertainties in input parameters and obtain the failure probability,the Monte Carlo simulation(MCS)method is employed,complemented by the Latin Hypercube Sampling(LHS)method to reduce the number of simulations.A parametric analysis is hence performed to examine the effect of several input pa-rameters(including both deterministic and probabilistic parameters)on the probability of column damage as a function of support rotation.First,the MSDOF method confirms its higher accuracy in estimating the probability of column damage due to blast,compared to the conventional SDOF.The collected results also show that un-certainties of several input parameters have significant effects on the column behavior.In particular,geometric parameters(including cross-sectional characteristics,boundary conditions and column length)have major effect on the corresponding column response,in the same way of input blast load parameters and material properties.展开更多
A floating horizontal-axis tidal current turbine(HATT)is an underwater power generation device where cavitation inevitably occurs on blade surfaces,severely affecting a turbine’s lifespan.Under wave action,these floa...A floating horizontal-axis tidal current turbine(HATT)is an underwater power generation device where cavitation inevitably occurs on blade surfaces,severely affecting a turbine’s lifespan.Under wave action,these floating turbines exhibit six degrees of freedom motion,potentially intensifying the cavitation on the blade surfaces.This study selects three types of oscillatory motions from the six degrees of freedom:roll,yaw,and pitch.Computational fluid dynamics(CFD)methods are used for numerical calculations,and transient simulations of multiphase flow are conducted on the basis of the Reynolds-Averaged Navier-Stokes(RANS)model.Research has revealed strong correlations between flow velocity,the blade tip speed ratio,and cavitation.During oscillatory motion,the motion period and amplitude also significantly impact cavitation.In roll motion,the cavitation rate can increase by up to 59%with decreasing period,whereas in pitch and yaw motions,the increases are 7.57 times and 36%larger,respectively.With an increase in amplitude during roll motion,the cavitation rate can increase by up to 1.08 times,whereas in pitch and yaw motions,the increases are 3.49 times and 45%,respectively.The cavitation rate on the blade surfaces is the highest in pitch motion,followed by roll and yaw motions.展开更多
基金Supported by National Natural Science Foundation of China(Grant Nos.51705066,51805128)Sichuan Science and Technology Program(Grant No.2019YFG0343)Fundamental Research Funds for the Central Universities of China(Grant Nos.ZYGX2019J041,ZYGX2016KYQD137).
文摘Conventional manipulators with rigid structures and sti ness actuators have poor flexibility,limited obstacle avoidance capability,and constrained workspace.Some developed flexible or soft manipulators in recent years have the characteristics of infinite degrees of freedom,high flexibility,environmental adaptability,and extended manipulation capability.However,these existing manipulators still cannot achieve the shrinking motion and independent control of specified segments like the animals,which hinders their applications.In this paper,a flexible bio-tensegrity manipulator,inspired by the longitudinal and transversal muscles of octopus tentacles,was proposed to mimic the shrinking behavior and achieve the variable motion patterns of each segment.Such proposed manipulator uses the elastic spring as the backbone,which is driven by four cables and has one variable structure mechanism in each segment to achieve the independent control of each segment.The variable structure mechanism innovatively contains seven lock-release states to independently control the bending and shrinking motion of each segment.After the kinematic modeling and analysis,one prototype of such bionic flexible manipulator was built and the open-loop control method was proposed.Some proof-of-concept experiments,including the shrinking motion,bending motion,and variable structure motion,were carried out by controlling the length of four cables and changing the lock-release states of the variable structure mechanism,which validate the feasibility and validity of our proposed prototype.Meanwhile,the experimental results show the flexible manipulator can accomplish the bending and shrinking motion with the relative error less than 6.8%through the simple independent control of each segment using the variable structure mechanism.This proposed manipulator has the features of controllable degree-of-freedom in each segment,which extend their environmental adaptability,and manipulation capability.
基金Project supported by the National Natural Science Foundation of China(Nos.11702170,11320011,and 11802279)the China Postdoctoral Science Foundation(No.2016M601585)
文摘Modal parameter identification is a mature technology.However,there are some challenges in its practical applications such as the identification of vibration systems involving closely spaced modes and intensive noise contamination.This paper proposes a new time-frequency method based on intrinsic chirp component decomposition(ICCD)to address these issues.In this method,a redundant Fourier model is used to ameliorate border distortions and improve the accuracy of signal reconstruction.The effectiveness and accuracy of the proposed method are illustrated using three examples:a cantilever beam structure with intensive noise contamination or environmental interference,a four-degree-of-freedom structure with two closely spaced modes,and an impact test on a cantilever rectangular plate.By comparison with the identification method based on the empirical wavelet transform(EWT),it is shown that the presented method is effective,even in a high-noise environment,and the dynamic characteristics of closely spaced modes are accurately determined.
文摘This study investigates the impact of information communication technology(ICT),economic freedom,and economic sustainability on herding behavior,and examines whether the link between economic freedom and economic sustainability depends on ICT.Using quantile regression on a sample of seven Gulf Cooperation Council stock markets from 2004 to 2020,we find that ICT and economic freedom reduce herding in lower quantiles while promoting it in higher quantiles.Conversely,open market freedom and economic sustainability appear to correct herding in all quantiles.The results show that ICT reinforces the move away from herding seen with economic freedom for the transmission channel of ICT on herding.However,ICT plays a dual role in open market freedom and economic sustainability,weakening(strengthening)the curative effect of economic sustainability(open market freedom)in the lower quantiles and strengthening(weakening)it in higher quantiles.Thus,the highest impact in reducing herding exits through the combination of ICT and economic freedom is skewed to the lower quantiles with ICT-open market freedom and skewed to the upper quantiles with ICT-economic sustainability.These results offer substantial implications for policymakers.
文摘The essence of academic freedom lies in scholars’autonomy in the pursuit of knowledge,free from external coercion and internal constraints,encompassing various aspects such as freedom of research,teaching,and learning.Leadership plays a crucial role in safeguarding academic freedom.Drawing on Macfarlane’s conceptualization of intellectual leadership,this article examines faculty-based agency protection,as well as institutional,cultural,and resource-based protections at the university level.
文摘Padma was 17 when the democratic reform was introduced in Xizang in 1959.Before the reform,the region had been ruled by feudal serfdom under a theocracy for centuries.Nearly one million serfs were subjected to estate-holders'cruel exploitation and oppression.Padma was one of them.
基金funded by the National College Students Innovation and Entrepreneurship Training Program(202411646031)the Zhejiang Xinmiao Talents Program(2024R405A052)the SRIP Research Program of Ningbo University(2025SRIP1707).
文摘The dynamic behavior of high-speed craft navigating through variable sea states plays a pivotal role in ensuring maritime safety.However,many existing simulation approaches rely on linear or overly simplified representations of the marine environment,thereby limiting the fidelity of motion predictions.This study explores the motion characteristics of a 4.5-t high-speed vessel by conducting fully coupled numerical simulations using the STAR-CCM+software.The analysis considers both calm and varying sea conditions,incorporating fluctuations in wave height,wavelength,and wind speed to reflect more realistic operating scenarios.Simulation results reveal that the vessel’s hydrodynamic response is highly sensitive to changes in sea state.As conditions deteriorate,the free surface becomes increasingly complex,with higher wave amplitudes and more pronounced interactions between the waves generated by the vessel and those imposed by the external environment.These effects lead to significant increases in roll,pitch,heave,and sway motions,thereby imposing greater demands on the vessel’s dynamic stability and operational safety.Furthermore,both hydrodynamic resistance and propulsive thrust exhibit notable dependence on sea state and vessel speed.Total resistance generally increases with rougher sea conditions,while thrust tends to rise with increasing forward speed.Under calm or mildly disturbed waters,a Froude number(Fr)of 0.5 appears to offer an optimal balance for initiating and controlling primary motions such as roll,pitch,heave,and sway.Conversely,in more challenging conditions-such as those represented by a Sea State 3-effective motion control is better achieved at a higher Froude number of approximately 1.0.
基金Guiding Science and Technology Program Project of Yichang City in 2024(Project No.:B24-2-002)。
文摘Objective:This study aimed to explore the effect of aromatherapy combined with emotional release technology on recurrence fear and sleep quality of lung cancer survivors.Methods:114 cases of lung cancer survivors were divided into routine nursing group,emotional release technology group and aromatherapy combined with emotional release technology group.Routine nursing group received routine nursing;Emotional release technology group implemented emotional release technology for one month on the basis of routine nursing group;Aromatherapy combined with emotional release technology group used lavender aromatherapy on the basis of emotional release technology group.Results:After one month of intervention,there were statistically significant differences in the scores of fear of disease progression and sleep quality among the three groups.Conclusion:Aromatherapy combined with emotional release technology can improve the sleep quality of lung cancer survivors and reduce the economic toxicity of cancer to some extent.
文摘“civil discourse”amongst multiple individuals with diverse viewpoints is necessary to move toward truth,to maintain democratic buoyancy,and to get the most accurate read on how best to move forward toward our collective good,civil discourse is nonetheless under catastrophic threat by contemporary forces that include the sloppy use of the term“hate speech”;the“libelling by labeling”(aka“cancelling”)in the public square of social media;technologically powered disinformation campaigns;and the growth of“safetyism”in academia.In light of these threats,the goal must be to convince educators,particularly philosophical educators,of the need to adopt a whole new focus in education,namely one that puts a spotlight on the fact that the utilization of the freedom of speech to destroy the freedom of speech of others utterly undermines the positive value of freedom of speech.In order to motivate individuals to turn their back on the dopamine rush of shutting someone down,educators must also spend a great deal of time showcasing the merits of“civil discourse”by providing young people with extensive experience in engaging in facilitated“civil discourse”(aka Communities of Philosophical Inquiry)so that its value can be woven into a personal commitment.
基金supported by the Key R&D Program of Shandong Province,China(No.2021ZLGX04)the National Natural Science Foundation of China(No.52171284)。
文摘The interaction between regular waves and an oscillating wave energy converter(WEC)in front of a vertical seawall is investigated using a 2D analytical model.A three-degree of freedom(DOF)WEC and a WEC hinged to the seawall(constrained to pitch mode)are considered to examine the influence of the DOF of the WEC on the wave energy extraction performance.Results show that the piston-mode water resonance in the gap and the coupled WEC and water column resonant motion significantly influence the wave energy extraction efficiency.At low frequency,the case with a 3-DOF WEC has a broader high-efficiency bandwidth than that with a heaving WEC.However,3-DOF WEC exhibits worse performance at high frequencies.The frequency response of the wave energy capture width ratio(CWR)for the pitching WEC case shows a trimodal trend under the specified conditions.It showcases the best overall wave energy extraction performance in terms of the high-efficiency bandwidth.Furthermore,a parametric study indicates that the gap distance between the WEC and the seawall has tremendous effects on the CWR of both cases.As the position of the hinge point of the pitching WEC changes,the CWR at the low and high frequencies shows opposite trends.
文摘This paper aims to evaluate the stochastic response of steel columns subjected to blast loads using the modified single degree of freedom(MSDOF)method,which assessed towards the conventional single degree of freedom(SDOF)and the experimentally validated Finite Element(FE)methods(LSDYNA).For this purpose,special atten-tion is given to calculating the response of H-shaped steel columns under blast.The damage amount is determined based on the support rotation criterion,which is expressed as a function of their maximum lateral mid-span dis-placement.To account for uncertainties in input parameters and obtain the failure probability,the Monte Carlo simulation(MCS)method is employed,complemented by the Latin Hypercube Sampling(LHS)method to reduce the number of simulations.A parametric analysis is hence performed to examine the effect of several input pa-rameters(including both deterministic and probabilistic parameters)on the probability of column damage as a function of support rotation.First,the MSDOF method confirms its higher accuracy in estimating the probability of column damage due to blast,compared to the conventional SDOF.The collected results also show that un-certainties of several input parameters have significant effects on the column behavior.In particular,geometric parameters(including cross-sectional characteristics,boundary conditions and column length)have major effect on the corresponding column response,in the same way of input blast load parameters and material properties.
基金supported by the National Natural Science Foundation of China(Grant No.52171261).
文摘A floating horizontal-axis tidal current turbine(HATT)is an underwater power generation device where cavitation inevitably occurs on blade surfaces,severely affecting a turbine’s lifespan.Under wave action,these floating turbines exhibit six degrees of freedom motion,potentially intensifying the cavitation on the blade surfaces.This study selects three types of oscillatory motions from the six degrees of freedom:roll,yaw,and pitch.Computational fluid dynamics(CFD)methods are used for numerical calculations,and transient simulations of multiphase flow are conducted on the basis of the Reynolds-Averaged Navier-Stokes(RANS)model.Research has revealed strong correlations between flow velocity,the blade tip speed ratio,and cavitation.During oscillatory motion,the motion period and amplitude also significantly impact cavitation.In roll motion,the cavitation rate can increase by up to 59%with decreasing period,whereas in pitch and yaw motions,the increases are 7.57 times and 36%larger,respectively.With an increase in amplitude during roll motion,the cavitation rate can increase by up to 1.08 times,whereas in pitch and yaw motions,the increases are 3.49 times and 45%,respectively.The cavitation rate on the blade surfaces is the highest in pitch motion,followed by roll and yaw motions.
