December  2016, 5(4): 567-603. doi: 10.3934/eect.2016020

Quasi-stability and exponential attractors for a non-gradient system---applications to piston-theoretic plates with internal damping

1. 

Department of Mathematics, College of Charleston, 66 George Street, Charleston, SC, 29424, United States

2. 

University of Memphis, Department of Mathematical Sciences, 373 Dunn Hall, Memphis, TN 38152

Received  July 2016 Revised  September 2016 Published  October 2016

We consider a nonlinear (Berger or Von Karman) clamped plate model with a piston-theoretic right hand side---which includes non-dissipative, non-conservative lower order terms. The model arises in aeroelasticity when a panel is immersed in a high velocity linear potential flow; in this case the effect of the flow can be captured by a dynamic pressure term written in terms of the material derivative of the plate's displacement. The effect of fully-supported internal damping is studied for both Berger and von Karman dynamics. The non-dissipative nature of the dynamics preclude the use of strong tools such as backward-in-time smallness of velocities and finiteness of the dissipation integral. Modern quasi-stability techniques are utilized to show the existence of compact global attractors and generalized fractal exponential attractors. Specific results here depend on the size of the damping parameter and the nonlinearity in force. For the Berger plate, in the presence of large damping, the existence of a proper global attractor (whose fractal dimension is finite in the state space) is shown via a decomposition of the nonlinear dynamics. This leads to the construction of a compact set upon which quasi-stability theory can be implemented. Numerical investigations for appropriate 1-D models are presented which explore and support the abstract results presented herein.
Citation: Jason S. Howell, Irena Lasiecka, Justin T. Webster. Quasi-stability and exponential attractors for a non-gradient system---applications to piston-theoretic plates with internal damping. Evolution Equations and Control Theory, 2016, 5 (4) : 567-603. doi: 10.3934/eect.2016020
References:
[1]

H. Ashley and G. Zartarian, Piston theory: A new aerodynamic tool for the aeroelastician, Journal of the Aeronautical Sciences, 23 (1956), 1109-1118. doi: 10.2514/8.3740.

[2]

M. Aouadi and A. Miranville, Quasi-stability and global attractor in nonlinear thermoelastic diffusion plate with memory, Evolutions Equations and Control Theory, 4 (2015), 241-263.

[3]

A. V. Babin and M. I. Vishik, Attractors of Evolution Equations, North-Holland Publishing Co., Amsterdam, 1992.

[4]

H. M. Berger, A new approach to the analysis of large deflections of plates, Journal of Applied Mechanics, 22 (1955), 465-472.

[5]

V. V. Bolotin, Nonconservative Problems of the Theory of Elastic Stability, The Macmillan Co., New York, 1963.

[6]

L. Bociu and D. Toundykov, Attractors for non-dissipative irrotational von Karman plates with boundary damping, Journal of Differential Equations, 253 (2012), 3568-3609. doi: 10.1016/j.jde.2012.08.004.

[7]

F. Bucci, I. Chueshov and I. Lasiecka, Global attractor for a composite system of nonlinear wave and plate equations, Communications on Pure and Applied Analysis, 6 (2007), 113-140.

[8]

F. Bucci and I. Chueshov, Long-time dynamics of a coupled system of nonlinear wave and thermoelastic plate equations, Dynamical Systems, 22 (2008), 557-586. doi: 10.3934/dcds.2008.22.557.

[9]

Z. Chbani and H. Riahi, Existence and asymptotic behavior for solutions of dynamical equilibrium systems, Evolution Equations and Control Theory, 3 (2014), 1-14.

[10]

I. Chueshov, Dynamics of Quasi-Stable Dissipative Systems, Springer, 2015. doi: 10.1007/978-3-319-22903-4.

[11]

I. Chueshov and I. Lasiecka, Long-time Behavior of Second Order Evolution Equations with Nonlinear Damping, American Mathematical Soc., 2008.

[12]

I. Chueshov and I. Lasiecka, Von Karman Evolution Equations: Well-posedness and Long Time Dynamics, Springer Science & Business Media, 2010. doi: 10.1007/978-0-387-87712-9.

[13]

I. Chueshov, E. H. Dowell, I. Lasiecka and J. T. Webster, Mathematical aeroelasticity: A survey, Mathematics in Engineering, Science and Aerospace, 7 (2016), 5-29.

[14]

I. Chueshov, E. H. Dowell, I. Lasiecka and J. T. Webster, Nonlinear elastic plate in a flow of gas: Recent results and conjectures, Applied Mathematics and Optimization, 73 (2016), 475-500. doi: 10.1007/s00245-016-9349-1.

[15]

I. Chueshov, I. Lasiecka and J. T. Webster, Attractors for delayed, nonrotational von Karman plates with applications to flow-structure interactions without any damping, Communications in Partial Differential Equations, 39 (2014), 1965-1997. doi: 10.1080/03605302.2014.930484.

[16]

I. Chueshov, I. Lasiecka and J. T. Webster, Evolution semigroups in supersonic flow-plate interactions, Journal of Differential Equations, 254 (2013), 1741-1773. doi: 10.1016/j.jde.2012.11.009.

[17]

P. G. Ciarlet, Mathematical Elasticity: Three-Dimensional Elasticity, Vol. 1, Elsevier, 1993.

[18]

E. Dowell, A Modern Course in Aeroelasticity, Kluwer Academic Publishers, 2004.

[19]

E. H. Dowell, Nonlinear oscillations of a fluttering plate I. AIAA Journal, 4 (1967), 1267-1275. Nonlinear oscillations of a fluttering plate. II. AIAA Journal, 5 (1966), 1856-1862.

[20]

P. Fabrie, C. Galusinski, A. Miranville and S. Zelik, Uniform exponential attractors for a singularly perturbed damped wave equation, Discrete and Continuous Dynamical Systems, 10 (2004), 211-238. doi: 10.3934/dcds.2004.10.211.

[21]

P. G. Geredeli, I. Lasiecka and J. T. Webster, Smooth attractors of finite dimension for von Karman evolutions with nonlinear frictional damping localized in a boundary layer, Journal of Differential Equations, 254 (2013), 1193-1229. doi: 10.1016/j.jde.2012.10.016.

[22]

P. G. Geredeli and J. T. Webster, Qualitative results on the dynamics of a Berger plate with nonlinear boundary damping, Nonlinear Analysis B: Real World Applications, 31 (2016), 227-256. doi: 10.1016/j.nonrwa.2016.02.002.

[23]

A. Haraux and M. Jendoubi, Asymptotics for a second order differential equation with a linear, slowly time decaying damping term, Evolution Equations and Control Theory, 2 (2013), 461-470.

[24]

A. A. Il'yushin, Law of plane sections in the aerodynamics of high supersonic velocities, Prikl. Mat. Mekh, 20 (1956), 733-755 (in Russian).

[25]

V. Kalantarov and S. Zelik, Finite-dimensional attractors for the quasi-linear strongly-damped wave equation, Journal of Differential Equations, 247 (2009), 1120-1155. doi: 10.1016/j.jde.2009.04.010.

[26]

A. K. Khanmamedov, Global attractors for von Karman equations with nonlinear interior dissipation, Journal of Mathematical Analysis and Applications, 318 (2006), 92-101. doi: 10.1016/j.jmaa.2005.05.031.

[27]

J. Lagnese, Boundary Stabilization of Thin Plates, SIAM Studies in Applied Mathematics, 1989. doi: 10.1137/1.9781611970821.

[28]

J. E. Lagnese and G. Leugering, Uniform stabilization of a nonlinear beam by nonlinear boundary feedback, Journal of Differential Equations, 91 (1991), 355-388. doi: 10.1016/0022-0396(91)90145-Y.

[29]

I. Lasiecka and R. Triggiani, Control Theory for Partial Differential Equations: Volume 1, Abstract Parabolic Systems: Continuous and Approximation Theories, Vol. 1, Cambridge University Press, 2000.

[30]

I. Lasiecka and J. Webster, Eliminating flutter for clamped von Karman plates immersed in subsonic flows, Communications on Pure & Applied Analysis, 13 (2014), 1935-1969. Updated version (May, 2015): http://arxiv.org/abs/1409.3308. doi: 10.3934/cpaa.2014.13.1935.

[31]

I. Lasiecka and J. T. Webster, Feedback stabilization of a fluttering panel in an inviscid subsonic potential flow, SIAM Journal on Mathematical Analysis, 48 (2016), 1848-1891. doi: 10.1137/15M1040529.

[32]

M. J. Lighthill, Oscillating airfoils at high mach number, Journal of the Aeronautical Sciences, 20 (1953), 402-406. doi: 10.2514/8.2657.

[33]

T. F. Ma and V. Narciso, Global attractor for a model of extensible beam with nonlinear damping and source terms, Nonlinear Analysis: Theory, Methods & Applications, 73 (2010), 3402-3412. doi: 10.1016/j.na.2010.07.023.

[34]

J. Malek and D. Prazak, Large time behavior via the method of $l$-trajectories, Journal of Differential Equations, 181 (2002), 243-279. doi: 10.1006/jdeq.2001.4087.

[35]

G. P. Menzala and E. Zuazua, Timoshenko's beam equation as limit of a nonlinear one-dimensional von Karman system, Proceedings of the Royal Society of Edinburgh: Section A Mathematics, 130 (2000), 855-875. doi: 10.1017/S0308210500000470.

[36]

G. P. Menzala and E. Zuazua, Timoshenko's plate equation as a singular limit of the dynamical von Karman system, Journal de mathématiques pures et appliquees, 79 (2000), 73-94. doi: 10.1016/S0021-7824(00)00149-5.

[37]

J. L. Nowinski and H. Ohnabe, On certain inconsistencies in Berger equations for large deflections of plastic plates, International Journal of Mechanical Sciences, 14 (1972), 165-170.

[38]

T. Saanouni, A note on global well-posedness and blow up of some semilinear evolution equations, Evolution Equations and Control Theory, 4 (2015), 355-372.

[39]

V. V. Vedeneev, Effect of damping on flutter of simply supported and clamped panels at low supersonic speeds, Journal of Fluids and Structures, 40 (2013), 366-372.

[40]

V. V. Vedeneev, Panel flutter at low supersonic speeds, Journal of Fluids and Structures, 29 (2012), 79-96.

[41]

C. P. Vendhan, A study of Berger equations applied to non-linear vibrations of elastic plates, International Journal of Mechanical Sciences, 17 (1975), 461-468.

[42]

J. T. Webster, Weak and strong solutions of a nonlinear subsonic flow-structure interaction: Semigroup approach, Nonlinear Analysis: Theory, Methods & Applications, 74 (2011), 3123-3136. doi: 10.1016/j.na.2011.01.028.

[43]

Z. Yang, On an extensible beam equation with nonlinear damping and source terms, Journal of Differential Equations, 254 (2013), 3903-3927. doi: 10.1016/j.jde.2013.02.008.

show all references

References:
[1]

H. Ashley and G. Zartarian, Piston theory: A new aerodynamic tool for the aeroelastician, Journal of the Aeronautical Sciences, 23 (1956), 1109-1118. doi: 10.2514/8.3740.

[2]

M. Aouadi and A. Miranville, Quasi-stability and global attractor in nonlinear thermoelastic diffusion plate with memory, Evolutions Equations and Control Theory, 4 (2015), 241-263.

[3]

A. V. Babin and M. I. Vishik, Attractors of Evolution Equations, North-Holland Publishing Co., Amsterdam, 1992.

[4]

H. M. Berger, A new approach to the analysis of large deflections of plates, Journal of Applied Mechanics, 22 (1955), 465-472.

[5]

V. V. Bolotin, Nonconservative Problems of the Theory of Elastic Stability, The Macmillan Co., New York, 1963.

[6]

L. Bociu and D. Toundykov, Attractors for non-dissipative irrotational von Karman plates with boundary damping, Journal of Differential Equations, 253 (2012), 3568-3609. doi: 10.1016/j.jde.2012.08.004.

[7]

F. Bucci, I. Chueshov and I. Lasiecka, Global attractor for a composite system of nonlinear wave and plate equations, Communications on Pure and Applied Analysis, 6 (2007), 113-140.

[8]

F. Bucci and I. Chueshov, Long-time dynamics of a coupled system of nonlinear wave and thermoelastic plate equations, Dynamical Systems, 22 (2008), 557-586. doi: 10.3934/dcds.2008.22.557.

[9]

Z. Chbani and H. Riahi, Existence and asymptotic behavior for solutions of dynamical equilibrium systems, Evolution Equations and Control Theory, 3 (2014), 1-14.

[10]

I. Chueshov, Dynamics of Quasi-Stable Dissipative Systems, Springer, 2015. doi: 10.1007/978-3-319-22903-4.

[11]

I. Chueshov and I. Lasiecka, Long-time Behavior of Second Order Evolution Equations with Nonlinear Damping, American Mathematical Soc., 2008.

[12]

I. Chueshov and I. Lasiecka, Von Karman Evolution Equations: Well-posedness and Long Time Dynamics, Springer Science & Business Media, 2010. doi: 10.1007/978-0-387-87712-9.

[13]

I. Chueshov, E. H. Dowell, I. Lasiecka and J. T. Webster, Mathematical aeroelasticity: A survey, Mathematics in Engineering, Science and Aerospace, 7 (2016), 5-29.

[14]

I. Chueshov, E. H. Dowell, I. Lasiecka and J. T. Webster, Nonlinear elastic plate in a flow of gas: Recent results and conjectures, Applied Mathematics and Optimization, 73 (2016), 475-500. doi: 10.1007/s00245-016-9349-1.

[15]

I. Chueshov, I. Lasiecka and J. T. Webster, Attractors for delayed, nonrotational von Karman plates with applications to flow-structure interactions without any damping, Communications in Partial Differential Equations, 39 (2014), 1965-1997. doi: 10.1080/03605302.2014.930484.

[16]

I. Chueshov, I. Lasiecka and J. T. Webster, Evolution semigroups in supersonic flow-plate interactions, Journal of Differential Equations, 254 (2013), 1741-1773. doi: 10.1016/j.jde.2012.11.009.

[17]

P. G. Ciarlet, Mathematical Elasticity: Three-Dimensional Elasticity, Vol. 1, Elsevier, 1993.

[18]

E. Dowell, A Modern Course in Aeroelasticity, Kluwer Academic Publishers, 2004.

[19]

E. H. Dowell, Nonlinear oscillations of a fluttering plate I. AIAA Journal, 4 (1967), 1267-1275. Nonlinear oscillations of a fluttering plate. II. AIAA Journal, 5 (1966), 1856-1862.

[20]

P. Fabrie, C. Galusinski, A. Miranville and S. Zelik, Uniform exponential attractors for a singularly perturbed damped wave equation, Discrete and Continuous Dynamical Systems, 10 (2004), 211-238. doi: 10.3934/dcds.2004.10.211.

[21]

P. G. Geredeli, I. Lasiecka and J. T. Webster, Smooth attractors of finite dimension for von Karman evolutions with nonlinear frictional damping localized in a boundary layer, Journal of Differential Equations, 254 (2013), 1193-1229. doi: 10.1016/j.jde.2012.10.016.

[22]

P. G. Geredeli and J. T. Webster, Qualitative results on the dynamics of a Berger plate with nonlinear boundary damping, Nonlinear Analysis B: Real World Applications, 31 (2016), 227-256. doi: 10.1016/j.nonrwa.2016.02.002.

[23]

A. Haraux and M. Jendoubi, Asymptotics for a second order differential equation with a linear, slowly time decaying damping term, Evolution Equations and Control Theory, 2 (2013), 461-470.

[24]

A. A. Il'yushin, Law of plane sections in the aerodynamics of high supersonic velocities, Prikl. Mat. Mekh, 20 (1956), 733-755 (in Russian).

[25]

V. Kalantarov and S. Zelik, Finite-dimensional attractors for the quasi-linear strongly-damped wave equation, Journal of Differential Equations, 247 (2009), 1120-1155. doi: 10.1016/j.jde.2009.04.010.

[26]

A. K. Khanmamedov, Global attractors for von Karman equations with nonlinear interior dissipation, Journal of Mathematical Analysis and Applications, 318 (2006), 92-101. doi: 10.1016/j.jmaa.2005.05.031.

[27]

J. Lagnese, Boundary Stabilization of Thin Plates, SIAM Studies in Applied Mathematics, 1989. doi: 10.1137/1.9781611970821.

[28]

J. E. Lagnese and G. Leugering, Uniform stabilization of a nonlinear beam by nonlinear boundary feedback, Journal of Differential Equations, 91 (1991), 355-388. doi: 10.1016/0022-0396(91)90145-Y.

[29]

I. Lasiecka and R. Triggiani, Control Theory for Partial Differential Equations: Volume 1, Abstract Parabolic Systems: Continuous and Approximation Theories, Vol. 1, Cambridge University Press, 2000.

[30]

I. Lasiecka and J. Webster, Eliminating flutter for clamped von Karman plates immersed in subsonic flows, Communications on Pure & Applied Analysis, 13 (2014), 1935-1969. Updated version (May, 2015): http://arxiv.org/abs/1409.3308. doi: 10.3934/cpaa.2014.13.1935.

[31]

I. Lasiecka and J. T. Webster, Feedback stabilization of a fluttering panel in an inviscid subsonic potential flow, SIAM Journal on Mathematical Analysis, 48 (2016), 1848-1891. doi: 10.1137/15M1040529.

[32]

M. J. Lighthill, Oscillating airfoils at high mach number, Journal of the Aeronautical Sciences, 20 (1953), 402-406. doi: 10.2514/8.2657.

[33]

T. F. Ma and V. Narciso, Global attractor for a model of extensible beam with nonlinear damping and source terms, Nonlinear Analysis: Theory, Methods & Applications, 73 (2010), 3402-3412. doi: 10.1016/j.na.2010.07.023.

[34]

J. Malek and D. Prazak, Large time behavior via the method of $l$-trajectories, Journal of Differential Equations, 181 (2002), 243-279. doi: 10.1006/jdeq.2001.4087.

[35]

G. P. Menzala and E. Zuazua, Timoshenko's beam equation as limit of a nonlinear one-dimensional von Karman system, Proceedings of the Royal Society of Edinburgh: Section A Mathematics, 130 (2000), 855-875. doi: 10.1017/S0308210500000470.

[36]

G. P. Menzala and E. Zuazua, Timoshenko's plate equation as a singular limit of the dynamical von Karman system, Journal de mathématiques pures et appliquees, 79 (2000), 73-94. doi: 10.1016/S0021-7824(00)00149-5.

[37]

J. L. Nowinski and H. Ohnabe, On certain inconsistencies in Berger equations for large deflections of plastic plates, International Journal of Mechanical Sciences, 14 (1972), 165-170.

[38]

T. Saanouni, A note on global well-posedness and blow up of some semilinear evolution equations, Evolution Equations and Control Theory, 4 (2015), 355-372.

[39]

V. V. Vedeneev, Effect of damping on flutter of simply supported and clamped panels at low supersonic speeds, Journal of Fluids and Structures, 40 (2013), 366-372.

[40]

V. V. Vedeneev, Panel flutter at low supersonic speeds, Journal of Fluids and Structures, 29 (2012), 79-96.

[41]

C. P. Vendhan, A study of Berger equations applied to non-linear vibrations of elastic plates, International Journal of Mechanical Sciences, 17 (1975), 461-468.

[42]

J. T. Webster, Weak and strong solutions of a nonlinear subsonic flow-structure interaction: Semigroup approach, Nonlinear Analysis: Theory, Methods & Applications, 74 (2011), 3123-3136. doi: 10.1016/j.na.2011.01.028.

[43]

Z. Yang, On an extensible beam equation with nonlinear damping and source terms, Journal of Differential Equations, 254 (2013), 3903-3927. doi: 10.1016/j.jde.2013.02.008.

[1]

Moncef Aouadi, Alain Miranville. Quasi-stability and global attractor in nonlinear thermoelastic diffusion plate with memory. Evolution Equations and Control Theory, 2015, 4 (3) : 241-263. doi: 10.3934/eect.2015.4.241

[2]

Dalibor Pražák. Exponential attractor for the delayed logistic equation with a nonlinear diffusion. Conference Publications, 2003, 2003 (Special) : 717-726. doi: 10.3934/proc.2003.2003.717

[3]

Francesca Bucci, Igor Chueshov, Irena Lasiecka. Global attractor for a composite system of nonlinear wave and plate equations. Communications on Pure and Applied Analysis, 2007, 6 (1) : 113-140. doi: 10.3934/cpaa.2007.6.113

[4]

Azer Khanmamedov, Sema Simsek. Existence of the global attractor for the plate equation with nonlocal nonlinearity in $ \mathbb{R} ^{n}$. Discrete and Continuous Dynamical Systems - B, 2016, 21 (1) : 151-172. doi: 10.3934/dcdsb.2016.21.151

[5]

I. D. Chueshov, Iryna Ryzhkova. A global attractor for a fluid--plate interaction model. Communications on Pure and Applied Analysis, 2013, 12 (4) : 1635-1656. doi: 10.3934/cpaa.2013.12.1635

[6]

Wided Kechiche. Regularity of the global attractor for a nonlinear Schrödinger equation with a point defect. Communications on Pure and Applied Analysis, 2017, 16 (4) : 1233-1252. doi: 10.3934/cpaa.2017060

[7]

Wided Kechiche. Global attractor for a nonlinear Schrödinger equation with a nonlinearity concentrated in one point. Discrete and Continuous Dynamical Systems - S, 2021, 14 (8) : 3027-3042. doi: 10.3934/dcdss.2021031

[8]

Tingting Liu, Qiaozhen Ma, Ling Xu. Attractor of the Kirchhoff type plate equation with memory and nonlinear damping on the whole time-dependent space. Discrete and Continuous Dynamical Systems - B, 2022  doi: 10.3934/dcdsb.2022046

[9]

Jianhua Huang, Yanbin Tang, Ming Wang. Singular support of the global attractor for a damped BBM equation. Discrete and Continuous Dynamical Systems - B, 2021, 26 (10) : 5321-5335. doi: 10.3934/dcdsb.2020345

[10]

Biyue Chen, Chunxiang Zhao, Chengkui Zhong. The global attractor for the wave equation with nonlocal strong damping. Discrete and Continuous Dynamical Systems - B, 2021, 26 (12) : 6207-6228. doi: 10.3934/dcdsb.2021015

[11]

S.V. Zelik. The attractor for a nonlinear hyperbolic equation in the unbounded domain. Discrete and Continuous Dynamical Systems, 2001, 7 (3) : 593-641. doi: 10.3934/dcds.2001.7.593

[12]

Dalibor Pražák. On the dimension of the attractor for the wave equation with nonlinear damping. Communications on Pure and Applied Analysis, 2005, 4 (1) : 165-174. doi: 10.3934/cpaa.2005.4.165

[13]

Zhiming Liu, Zhijian Yang. Global attractor of multi-valued operators with applications to a strongly damped nonlinear wave equation without uniqueness. Discrete and Continuous Dynamical Systems - B, 2020, 25 (1) : 223-240. doi: 10.3934/dcdsb.2019179

[14]

Rolci Cipolatti, Otared Kavian. On a nonlinear Schrödinger equation modelling ultra-short laser pulses with a large noncompact global attractor. Discrete and Continuous Dynamical Systems, 2007, 17 (1) : 121-132. doi: 10.3934/dcds.2007.17.121

[15]

Oleksiy V. Kapustyan, Pavlo O. Kasyanov, José Valero. Structure and regularity of the global attractor of a reaction-diffusion equation with non-smooth nonlinear term. Discrete and Continuous Dynamical Systems, 2014, 34 (10) : 4155-4182. doi: 10.3934/dcds.2014.34.4155

[16]

Antonio Segatti. Global attractor for a class of doubly nonlinear abstract evolution equations. Discrete and Continuous Dynamical Systems, 2006, 14 (4) : 801-820. doi: 10.3934/dcds.2006.14.801

[17]

Wenxian Shen. Global attractor and rotation number of a class of nonlinear noisy oscillators. Discrete and Continuous Dynamical Systems, 2007, 18 (2&3) : 597-611. doi: 10.3934/dcds.2007.18.597

[18]

Wenjun Liu, Hefeng Zhuang. Global attractor for a suspension bridge problem with a nonlinear delay term in the internal feedback. Discrete and Continuous Dynamical Systems - B, 2021, 26 (2) : 907-942. doi: 10.3934/dcdsb.2020147

[19]

Olivier Goubet, Ezzeddine Zahrouni. Global attractor for damped forced nonlinear logarithmic Schrödinger equations. Discrete and Continuous Dynamical Systems - S, 2021, 14 (8) : 2933-2946. doi: 10.3934/dcdss.2020393

[20]

Milena Stanislavova. On the global attractor for the damped Benjamin-Bona-Mahony equation. Conference Publications, 2005, 2005 (Special) : 824-832. doi: 10.3934/proc.2005.2005.824

2020 Impact Factor: 1.081

Metrics

  • PDF downloads (109)
  • HTML views (0)
  • Cited by (4)

[Back to Top]