THE LIMITING SENSITIVITY OF SEISMIC DETECTORS

Geophysics ◽  
1942 ◽  
Vol 7 (2) ◽  
pp. 115-122 ◽  
Author(s):  
Alfred Wolf
Keyword(s):  
Brownian Motion ◽  
Ground Motions ◽  
Thermal Fluctuations ◽  
Power Generator ◽  
Recording Apparatus ◽  
Voltage Limit

The theory of Brownian motion is applied to the problem of determination of the limiting sensitivity of seismic detectors. It is shown that a certain minimum suspended mass is requird for the recording of small ground motions. Electromagnetic geophones are studied in detail, and it is shown how spontaneous thermal fluctuations in voltage limit the performance of these instruments. Under certain conditions, a geophone may be treated as a power generator, and the necessary suspended mass is then determined by the power requirements of the recording apparatus.

The Fluctuating Lattice Boltzmann

2018 ◽  
Author(s):  
Sauro Succi
Keyword(s):  
Brownian Motion ◽  
Fluid Flow ◽  
Lattice Boltzmann ◽  
Thermal Fluctuations ◽  
Directed Motion ◽  
Statistical Fluctuations ◽  
Lattice Boltzmann Models ◽  
Motion Versus ◽  
The Way

Fluid flow at nanoscopic scales is characterized by the dominance of thermal fluctuations (Brownian motion) versus directed motion. Thus, at variance with Lattice Boltzmann models for macroscopic flows, where statistical fluctuations had to be eliminated as a major cause of inefficiency, at the nanoscale they have to be summoned back. This Chapter illustrates the “nemesis of the fluctuations” and describe the way they have been inserted back within the LB formalism. The result is one of the most active sectors of current Lattice Boltzmann research.

scholarly journals Channel noise in nerve membranes and lipid bilayers

1975 ◽  
Vol 8 (4) ◽  
pp. 451-506 ◽  
Author(s):  
F Conti ◽  
E. Wanke
Keyword(s):  
Brownian Motion ◽  
Lipid Bilayers ◽  
Fluctuation Phenomena ◽  
Channel Noise ◽  
Fluctuation Analysis ◽  
Electronic Charge ◽  
Basic Principles ◽  
Avogadro’S Number ◽  
Insight Into

The basic principles underlying fluctuation phenomena in thermodynamics have long been understood (for reviews see Kubo, 1957; Kubo, Matsuo & Kazuhiro 1973 Lax, 1960). Classical examples of how fluctuation analysis can provide an insight into the corpuscular nature of matter are the determination of Avogadro's number according to Einstein's theory of Brownian motion (see, e.g. Uhlenbeck & Ornstein, 1930; Kac, 1947) and the evaluation of the electronic charge from the shot noise in vacuum tubes (see Van der Ziel, 1970).

Brownian Motion

2018 ◽  
pp. 1-24
Author(s):  
Giovanni Zocchi
Keyword(s):  
Brownian Motion ◽  
Statistical Mechanics ◽  
Concentration Gradient ◽  
Nonequilibrium Statistical Mechanics ◽  
Thermal Fluctuations ◽  
Nonequilibrium System ◽  
Individual Particle ◽  
Equilibrium Concept ◽  
Self Diffusion ◽  
Main Ideas

This chapter provides an introduction to the main ideas of Brownian motion. Brownian motion connects equilibrium and nonequilibrium statistical mechanics. It connects diffusion—a nonequilibrium phenomenon—with thermal fluctuations—an equilibrium concept. More precisely, diffusion with a net flow of particles, driven by a concentration gradient, pertains to a nonequilibrium system, since there is a net current. Without a concentration gradient, the system is macroscopically in equilibrium, but each individual particle undergoes self-diffusion just the same. In this sense, Brownian motion is at the border of equilibrium and nonequilibrium statistical mechanics.

scholarly journals Thermal Fluctuations in Electric Circuits and the Brownian Motion

2010 ◽  
Vol 61 (4) ◽  
pp. 252-256 ◽  
Author(s):  
Gabriela Vasziová ◽  
Jana Tóthová ◽  
Lukáš Glod ◽  
Vladimír Lisý
Keyword(s):  
Brownian Motion ◽  
Brownian Particle ◽  
Mean Square Displacement ◽  
Thermal Fluctuations ◽  
Stochastic Equations ◽  
Thermal Bath ◽  
Current Fluctuations ◽  
Electric Circuits ◽  
The Mean ◽  
Optically Trapped

Thermal Fluctuations in Electric Circuits and the Brownian MotionIn this work we explore the mathematical correspondence between the Langevin equation that describes the motion of a Brownian particle (BP) and the equations for the time evolution of the charge in electric circuits, which are in contact with the thermal bath. The mean quadrate of the fluctuating electric charge in simple circuits and the mean square displacement of the optically trapped BP are governed by the same equations. We solve these equations using an efficient approach that allows us converting the stochastic equations to ordinary differential equations. From the obtained solutions the autocorrelation function of the current and the spectral density of the current fluctuations are found. As distinct from previous works, the inertial and memory effects are taken into account.

Micromachined Linear Brownian Motor: A Nanosystem Exploting Brownian Motion of Nanobeads for Uni-directional Transport

2008 ◽  
Vol 1096 ◽  
Author(s):  
Ersin Altintas ◽  
Edin Sarajlic ◽  
Karl F. Bohringer ◽  
Hiroyuki Fujita
Keyword(s):  
Brownian Motion ◽  
Three Dimensional ◽  
Thermal Fluctuations ◽  
Random Motion ◽  
Microfluidic Channels ◽  
Switching Sequence ◽  
Brownian Motor ◽  
Speed Performance ◽  
Random Fluctuations ◽  
Directional Transport

AbstractNanosystems operating in liquid media may suffer from random thermal fluctuations. Some natural nanosystems, e.g. biomolecular motors, which survive in an environment where the energy required for bio-processes is comparable to thermal energy, exploit these random fluctuations to generate a controllable unidirectional movement. Inspired by the nature, a transportation system of nanobeads achieved by exploiting Brownian motion were proposed and realized. This decreases energy consumption and saves the energy compared to ordinal pure electric or magnetic drive. In this paper we present a linear Brownian motor with a 3-phase electrostatic rectification aimed for unidirectional transport of nanobeads in microfluidic channels. The transport of the beads is performed in 1 μm deep, 2 μm wide PDMS microchannels, which constrain three-dimensional random motion of nanobeads into 1D fluctuation, so-called tamed Brownian motion. We have experimentally traced the rectified motion of nanobeads and observed the shift in the beam distribution as a function of applied voltage. The detailed computational analysis on the importance of switching sequence on the speed performance of motor is performed and compared with the experimental results showing a good agreement.

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