Video Experimental Relacionado
Updated: Jul 15, 2026
10:28
Experimental Measurement of Settling Velocity of Spherical Particles in Unconfined and Confined Surfactant-based Shear Thinning Viscoelastic Fluids
Published on: January 3, 2014
Mecánica estadística de una partícula gas-fluidizada
R P Ojha1, P-A Lemieux, P K Dixon
1Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547, USA.
Nature
|February 7, 2004
Resumen
Los sistemas lejos del equilibrio pueden ser entendidos usando la temperatura efectiva. Este estudio muestra que una sola esfera en el flujo de gas sigue sorprendentemente la mecánica estadística de casi equilibrio, validando el concepto de temperatura efectiva.
Área de la Ciencia:
- La mecánica estadística es la mecánica estadística.
- Los sistemas de no equilibrio no están en equilibrio.
- Sistemas complejos de sistemas complejos.
Sus antecedentes:
- La caracterización de las fluctuaciones microscópicas en sistemas lejos del equilibrio es clave para comprender el comportamiento macroscópico.
- El concepto de "temperatura efectiva" se ha aplicado a varios sistemas complejos, incluidos fluidos, vidrios y materiales granulares.
- La validez de la temperatura efectiva en sistemas de no equilibrio sigue siendo una cuestión abierta.
Objetivo del estudio:
- Investigar experimentalmente la validez del concepto de temperatura efectiva.
- Para determinar si los principios de mecánica estadística cercanos al equilibrio se aplican a los sistemas impulsados lejos del equilibrio.
- Para analizar la dinámica de una sola partícula en un flujo de gas turbulento.
Principales métodos:
- Utilizó una sola esfera en una pantalla en un flujo ascendente de gas, generando turbulencia.
- Empleó imágenes de video para capturar completamente la dinámica de la esfera.
- Analizó el sistema en busca de interacciones partícula-partícula, pero no encontró ninguna.
Principales resultados:
- Se descubrió que el movimiento de la esfera es análogo a una partícula browniana unida armónicamente.
- La fuerza motriz aleatoria y el arrastre dependiente de la frecuencia satisfacían la relación fluctuación-disolución.
- El sistema demostró un comportamiento consistente con la mecánica estadística de casi equilibrio.
Conclusiones:
- La relación fluctuación-disolución, un aspecto fundamental de la mecánica estadística de casi equilibrio, es aplicable a este sistema impulsado por el no equilibrio.
- El concepto de temperatura efectiva es inesperadamente válido para ciertas clases de sistemas lejos del equilibrio.
- Este sistema simplificado de una sola partícula proporciona un modelo tratable para el estudio de los fenómenos de no equilibrio.
Más Videos Relacionados
Videos de Conceptos Relacionados
02:43Basic Postulates of Kinetic Molecular Theory: Particle Size, Energy, and Collision
The ideal-gas equation, which is empirical, describes the behavior of gases by establishing relationships between their macroscopic properties. For example, Charles’ law states that volume and temperature are directly related. Gases, therefore, expand when heated at constant pressure. Although gas laws explain how the macroscopic properties change relative to one another, it does not explain the rationale behind it.
02:34Kinetic Molecular Theory and Gas Laws Explain Properties of Gas Molecules
The test of the kinetic molecular theory (KMT) and its postulates is its ability to explain and describe the behavior of a gas. The various gas laws (Boyle’s, Charles’s, Gay-Lussac’s, Avogadro’s, and Dalton’s laws) can be derived from the assumptions of the KMT, which have led chemists to believe that the assumptions of the theory accurately represent the properties of gas molecules.
01:12Kinetic Theory of an Ideal Gas
A mole is defined as the amount of any substance that contains as many molecules as there are atoms in exactly 12 grams of carbon-12. An Italian scientist Amedeo Avogadro (1776–1856) formed the hypothesis that equal volumes of gas at equal pressure and temperature contain equal numbers of molecules, independent of the type of gas. Later, the hypothesis was developed to form the SI unit for measuring the amount of any substance.
The number of molecules in one mole is called Avogadro's number...
The number of molecules in one mole is called Avogadro's number...
01:27Distribution of Molecular Speeds
The motion of molecules in a gas is random in magnitude and direction for individual molecules, but a gas of many molecules has a predictable distribution of molecular speeds. This predictable distribution of molecular speeds is known as the Maxwell-Boltzmann distribution. The distribution of molecular speeds in liquids is comparable to that of gases but not identical and can help to understand the phenomenon of the boiling and vapor pressure of a liquid. Consider that a molecule requires a...
01:20Maxwell-Boltzmann Distribution: Problem Solving
Individual molecules in a gas move in random directions, but a gas containing numerous molecules has a predictable distribution of molecular speeds, which is known as the Maxwell-Boltzmann distribution, f(v).
This distribution function f(v) is defined by saying that the expected number N (v1,v2) of particles with speeds between v1 and v2 is given by
This distribution function f(v) is defined by saying that the expected number N (v1,v2) of particles with speeds between v1 and v2 is given by
01:24The Kinetic Model of Gases
The kinetic model of gases explains the properties of a perfect gas using three main assumptions: molecules move in ceaseless random motion, their size is negligible compared to the distances between them, and they do not interact except during perfectly elastic collisions. The total energy of a gas is the sum of the kinetic energies of all its constituent molecules. The pressure exerted by the gas arises from the continual bombardment of the container walls by billions of colliding molecules.