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I.Introduction A.Objectives for this lab: 1.Learn about statistical physics in a system, specifically the two-dimensional random walk 2.Understand how the motion of self-propelled organisms differs from Brownian motion B.In this lab, you'll explore Brownian motion. You'll observe a micron-sized sphere under a microscope and watch as it undergoes a random walk in two dimensions. You'll then quantitatively analyze its motion and measure its diffusion constant. Using known properties of the sphere, you can then experimentally determine Boltzmann's constant and Avogadro's number, just as Einstein and Perrin did in the early 20th century (which led to Perrin's 1926 Nobel Prize in Physics). Finally, you'll get a chance to observe motion that is not Brownian, but rather due to self-propelled micro-organisms.
You'll observe a micron-sized sphere under a microscope and watch as it undergoes a random walk in two dimensions.
1.At the sample preparation station, there are also solutions containing biological samples. Make up a microscope slide containing one of these solutions.
2. Perform a short video analysis (~30 seconds) on one of the creatures you find. Be sure to uncheck "Time Lapse".
3. What is the creature's typical speed as it moves around?
4. What do you notice qualitatively about the motion of these biological samples? How does it differ from the Brownian motion of the microspheres?
originally posted by: TEOTWAWKIAIFF
a reply to: TheLotLizard
You missed the term, "crystal homology", where crystals are defined by "sp" orbital bonds. Graphene is sp-2 and is grown atomically flat. Sp-3 bonds include diamond and buckyballs (actually, that one is more like sp-2.5).
A plane has two sides, do you call that 3D? No, you do not. As far as crystals go, which graphene is one, it is considered a 2D material with all the properties associated therein. Including being affected by Brownian motion in a 2D plane (this has never occurred in a 3D material) which is the point of the OP.
A previous attempt at extracting energy from Brownian Motion was the Brownian Ratchet, researched by famous physicist Richard Feynman. The ratchet failed since particles hit the pawl (latch) which made the ratchet erratic and bounce back and forth. In the Olson thought experiments, no pawl is needed to separate hot and cold since vibrations are exploited without any ratchet device. Separating hot from cold is the primary concern in the Olson devices rather than directed motion. Static discharges of electricity or eddy currents (creating heat) or viscosity (liquid friction) are used in the Olson thought experiments to separate hot from cold. How does one extract energy from the devices? Once one separates hot from cold he can extract energy later – the primary concern is to separate hot and cold first, not to obtain ordered motion in a ratchet-like device.
The Brownian Ratchet tried to force Brownian motion into one directional movement in a system where particles were everywhere (hitting the pawl). The Olson systems are engineered without pawls and are like regenerative nano brakes. They dissipate heat or generate random electrical charges which could be stored later in a capacitor, all without any cold sink. A cold sink is emulated by taking advantage of nonequilibrium properties such as viscosity differential and electrostatic electron affinity differential.
Does Brownian motion produce heat? Or take up the heat?
If it takes up the heat or converts the heat to it's (kinetic) motion, where does the energy then go? In other words, what is the energy then converted to?
If Brownian motion produces heat the moving particles must be losing mass ....no?
Static discharges of electricity or eddy currents (creating heat) or viscosity (liquid friction) are used in the Olson thought experiments to separate hot from cold. How does one extract energy from the devices? Once one separates hot from cold he can extract energy later – the primary concern is to separate hot and cold first, not to obtain ordered motion in a ratchet-like device.
The Brownian Ratchet tried to force Brownian motion into one directional movement in a system where particles were everywhere (hitting the pawl). The Olson systems are engineered without pawls and are like regenerative nano brakes. They dissipate heat or generate random electrical charges which could be stored later in a capacitor, all without any cold sink. A cold sink is emulated by taking advantage of nonequilibrium properties such as viscosity differential and electrostatic electron affinity differential.
Why it fails[edit]
Although at first sight, the Brownian ratchet seems to extract useful work from Brownian motion, Feynman demonstrated that if the entire device is at the same temperature, the ratchet will not rotate continuously in one direction but will move randomly back and forth, and therefore will not produce any useful work. The reason is that the pawl, since it is at the same temperature as the paddle, will also undergo Brownian motion, "bouncing" up and down. It, therefore, will intermittently fail by allowing a ratchet tooth to slip back under the pawl while it is up. Another issue is that when the pawl rests on the sloping face of the tooth, the spring which returns the pawl exerts a sideways force on the tooth which tends to rotate the ratchet in a backward direction. Feynman demonstrated that if the temperature
T 2 [displaystyle T_[2]]
of the ratchet and pawl is the same as the temperature
T 1 [displaystyle T_[1]]
of the paddle, then the failure rate must equal the rate at which the ratchet ratchets forward so that no net motion results over long enough periods or in an ensemble-averaged sense.[2] A simple but rigorous proof that no net motion occurs no matter what shape the teeth are was given by Magnasco.[3]
If, on the other hand,
T 2 [displaystyle T_[2]]
is smaller than
1 [displaystyle T_[1]]
, the ratchet will indeed move forward and produce useful work. In this case, though, the energy is extracted from the temperature gradient between the two thermal reservoirs, and some waste heat is exhausted into the lower temperature reservoir by the pawl. In other words, the device functions as a miniature heat engine, in compliance with the second law of thermodynamics. Conversely, if
T 2 [displaystyle T_[2]]
is greater than
T 1 [displaystyle T_[1]]
, the device will rotate in the opposite direction.The Feynman ratchet model led to the similar concept of Brownian motors, nanomachines which can extract useful work not from thermal noise but from chemical potentials and other microscopic nonequilibrium sources, in compliance with the laws of thermodynamics.[3][4] Diodes are an electrical analog of the ratchet and pawl, and for the same reason cannot produce useful work by rectifying Johnson noise in a circuit at a uniform temperature.
Millions [5], as well as Mahato [6], extended the same notion to correlation ratchets driven by mean-zero (unbiased) nonequilibrium noise with a nonvanishing correlation function of odd order greater than one.
originally posted by: Phage
a reply to: Kashai
So build one. The world will beat a path to your door.
Resonant frequency problems are often encountered in mechanical systems. When this occurs, the level of vibration is generally quite high, and this in turn often causes premature failure of machine components. Often, attempts are made to address the problem by reducing the forcing function. Such courses of action include dynamic balancing of rotating elements and aligning coupled components. It is very important to maintain good balance and alignment. However, in the case of a resonant condition, the primary problem is generally not the magnitude of the forcing function. The problem is that a forcing function, which may be of modest magnitude, matches a system resonance or natural frequency. In such a case, the amplification factor of the vibration can be many fold. The amplification factor is the ratio of the peak dynamic displacement imparted on a system by an oscillating force with a given peak magnitude compared with the displacement imparted by a static force of the same magnitude. Figure 1 is a plot of the amplification factor versus resonant frequency ratio for several systems each with a different level of damping. The resonant frequency ratio is the ratio of the forcing frequency to the resonant frequency. A value of one indicates that the system is at resonance.
Brownian Particles area about 1 micron in diameter (1/1000th of a millimeter), Water Molecules are about 10,000 times smaller in diameter!
A discussion that theoretically explains the main reasons why the constructed state space model can result in high remaining useful life prediction accuracies are provided. Finally, the proposed state space model and its associated Kalman filtering gain are applied to battery prognostics.
originally posted by: TEOTWAWKIAIFF
a reply to: chr0naut
Why not do both?
Ambient heat and ambient EM waves all being turned back into electricity for repurpose.
Purpose driven recycling. You might need it if you heading off to Mars or Deep Space 9!