World Library  
Flag as Inappropriate
Email this Article

Brownian motor

Article Id: WHEBN0000508390
Reproduction Date:

Title: Brownian motor  
Author: World Heritage Encyclopedia
Language: English
Subject: Molecular motor, Nanotechnology, Thermodynamics, Quantum biology, Brownian ratchet
Collection: Nanotechnology, Thermodynamics
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Brownian motor

Brownian motors are nano-scale or molecular devices by which thermally activated processes (chemical reactions) are controlled and used to generate directed motion in space and to do mechanical or electrical work. These tiny engines operate in an environment where viscosity dominates inertia, and where thermal noise makes moving in a specific direction as difficult as walking in a hurricane: the forces impelling these motors in the desired direction are minuscule in comparison with the random forces exerted by the environment. Because this type of motor is so strongly dependent on random thermal noise, Brownian motors are feasible only at the nanometer scale.

The term "Brownian motor" was originally coined by Peter Hänggi in 1995: A distinct feature of a Brownian motor is—in contrast to a molecular motor—that the output response is typically coupled only loosely to the input perturbation and action of fluctuations; see in Hänggi, Peter; Marchesoni, Fabio (2009). "Artificial Brownian motors: Controlling transport on the nanoscale" (PDF). Reviews of Modern Physics 81 (1): 387.  .

In biology, many protein-based molecular motors in the cell may in fact be Brownian motors. These molecular motors convert the chemical energy present in ATP into mechanical energy. One example of a Brownian motor would be an ATPase motor that hydrolyzes ATP to generate fluctuating anisotropic energetic potentials. The anisotropic potentials along the path would bias the motion of a particle (like an ion or polypeptide); the result would essentially be diffusion of a particle whose net motion is strongly biased in one direction. The translocation of the particle would only be loosely coupled to hydrolysis of ATP.

The dynamics and activity of Brownian motors are current topics of study in theoretical and experimental biophysics. Brownian motors are sometimes modeled using the Fokker-Planck equation or with Monte Carlo methods. Many researchers are presently engaged in understanding how molecular-scale motors operate in environments with non-negligible thermal noise. The thermodynamics of such motors is constrained by the ramifications of the Fluctuation Theorems, Pumping Quantization Theorems,[1] and Pumping-Restriction Theorems.[2]

See also

Notes

  1. ^ V. Y. Chernyak and N. A. Sinitsyn (2009). "Robust quantization of a molecular motor motion in a stochastic environment". J. Chem. Phys. 131 (18): 181101.  
  2. ^ V. Y. Chernyak and N. A. Sinitsyn (2008). "Pumping-Restriction Theorem for stochastic networks". Phys. Rev. Lett. 101 (16): 160601.  

External links

  • Magnasco, M. O. (1993). "Forced thermal ratchets". Phys. Rev. Lett. 71 (10): 1477–1481.  
  • Magnasco, M. O. (1994). "Molecular Combustion Motors". Phys. Rev. Lett. 72 (16): 2656–2659.  
  • Astumian, R. D. (1997). "Thermodynamics and kinetics of a Brownian motor". Science 276 (5314): 917–922.  
  • Astumian, R. D.; Hänggi, P. (2002). "Brownian Motors" (PDF). Physics Today 55 (11): 33–39.  
  • Hänggi, P.; Marchesoni, F.; Nori, F. (2005). "Brownian Motors" (PDF). Ann Physik 14 (1-3): 51–70.  
  • Freund, J. A.; Pöschel, T. (2000). "Stochastic processes in physics, chemistry, and biology". Lecture notes in physics, vol. 557. Berlin: Springer.  
  • Lukasz Machura: Performance of Brownian Motors. University of Augsburg, 2006 (PDF)
  • Brownian motor on arxiv.org
  • Hänggi, Peter; Marchesoni, Fabio (2009). "Artificial Brownian motors: Controlling transport on the nanoscale" (PDF). Reviews of Modern Physics 81 (1): 387.  
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.