Effective Temperature in Active Brownian Particles

2019 ◽  
Vol 18 (02) ◽  
pp. 1940008 ◽  
Author(s):  
Leticia F. Cugliandolo ◽  
Giuseppe Gonnella ◽  
Isabella Petrelli
Keyword(s):  
Numerical Analysis ◽  
Effective Temperature ◽  
Spherical Particles ◽  
Excluded Volume ◽  
Low Density ◽  
Homogeneous Phase ◽  
Fluctuation Dissipation ◽  
Fluctuation Dissipation Theorem ◽  
Brownian Particles ◽  
The One

In this paper, we perform a numerical analysis of the effective temperature extracted from the deviations from the fluctuation dissipation theorem in a system of active Brownian spherical particles with excluded volume interactions. We show that, in the low density homogeneous phase at fixed Péclet number, the effective temperature decreases when the density of the system is increased. We compare this trend to the one found in the literature with simulations of other active models.

Effective temperature inside living cells

2009 ◽  
Vol 1227 ◽  
Author(s):  
Claire Wilhelm
Keyword(s):  
Effective Temperature ◽  
Magnetic Beads ◽  
Complex Modulus ◽  
Living Cells ◽  
Passive Measurement ◽  
Fluctuation Dissipation ◽  
Fluctuation Dissipation Theorem ◽  
Active Measurement ◽  
Oscillating Magnetic Field ◽  
Magnetic Probes

AbstractThe combination of active and passive microrheology using magnetic probes engulfed inside living cells demonstrates the violation of the fluctuation dissipation theorem in cells. It is proposed to quantify the deviation from the in equilibrium situation with an effective temperature. Each magnetic probe then serves as a local thermometer within the cells. The response of pairs of magnetic beads of two diameters (1 and 2.8 μm) to an oscillating magnetic field is analyzed to measure the viscoelastic complex modulus in the beads environment (active measurement). The spontaneous motion of the beads is tracked to compute their mean square displacements (passive measurement). The effective temperature is derived using an extension of the fluctuation dissipation theorem.

scholarly journals Numerical Analysis of Thermophoresis of a Charged Spheroidal Colloid in Aqueous Media

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 224
Author(s):  
Yi Zhou ◽  
Yang Yang ◽  
Changxing Zhu ◽  
Mingyuan Yang ◽  
Yi Hu
Keyword(s):  
Numerical Analysis ◽  
Aqueous Media ◽  
Concentration Field ◽  
Ion Concentration ◽  
Spherical Particles ◽  
Hydrodynamic Effect ◽  
Oblate Spheroids ◽  
Thermodiffusion Coefficient ◽  
Arbitrary Electric Double Layer ◽  
Dimension Ratio

Thermophoresis of charged colloids in aqueous media has wide applications in biology. Most existing studies of thermophoresis focused on spherical particles, but biological compounds are usually non-spherical. The present paper reports a numerical analysis of the thermophoresis of a charged spheroidal colloid in aqueous media. The model accounts for the strongly coupled temperature field, the flow field, the electric potential field, and the ion concentration field. Numerical simulations revealed that prolate spheroids move faster than spherical particles, and oblate spheroids move slower than spherical particles. For the arbitrary electric double layer (EDL) thickness, the thermodiffusion coefficient of prolate (oblate) spheroids increases (decreases) with the increasing particle’s dimension ratio between the major and minor semiaxes. For the extremely thin EDL case, the hydrodynamic effect is significant, and the thermodiffusion coefficient for prolate (oblate) spheroids converges to a fixed value with the increasing particle’s dimension ratio. For the extremely thick EDL case, the particle curvature’s effect also becomes important, and the increasing (decreasing) rate of thermodiffusion coefficient for prolate (oblate) spheroids is reduced slightly.

scholarly journals Low-Density Insulation Blocks and Hardboards from Amaranth (Amaranthus cruentus) Stems, a New Perspective for Building Applications

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 349
Author(s):  
Philippe Evon ◽  
Guyonne de Langalerie ◽  
Laurent Labonne ◽  
Othmane Merah ◽  
Thierry Talou ◽  
...  
Keyword(s):  
Aerial Part ◽  
Low Density ◽  
Renewable Materials ◽  
Fractionation Process ◽  
Amaranthus Cruentus ◽  
Cosmetic Industry ◽  
New Perspective ◽  
The One ◽  
Promising Source ◽  
Amaranth Oil

Nowadays, amaranth appears as a promising source of squalene of vegetable origin. Amaranth oil is indeed one of the most concentrated vegetable oils in squalene, i.e., up to 6% (w/w). This triterpene is highly appreciated in cosmetology, especially for the formulation of moisturizing creams. It is almost exclusively extracted from the liver of sharks, causing their overfishing. Thus, providing a squalene of renewable origin is a major challenge for the cosmetic industry. The amaranth plant has thus experienced renewed interest in recent years. In addition to the seeds, a stem is also produced during cultivation. Representing up to 80% (w/w) of the plant aerial part, it is composed of a ligneous fraction, the bark, on its periphery, and a pith in its middle. In this study, a fractionation process was developed to separate bark and pith. These two fractions were then used to produce renewable materials for building applications. On the one hand, the bark was used to produce hardboards, with the deoiled seeds acting as natural binder. Such boards are a viable alternative to commercial wood-based panels. On the other hand, the pith was transformed into cohesive and machinable low-density insulation blocks revealing a low thermal conductivity value.

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