On simple scaling laws for pumping fluids with electrically-charged particles

2018 ◽  
Vol 123 ◽  
pp. 73-80 ◽  
Author(s):  
Tarek I. Zohdi
Keyword(s):  
Scaling Laws ◽  
Charged Particles ◽  
Simple Scaling ◽  
Electrically Charged

Micro Thermal Engines: Is There Any Room at the Bottom?

1999 ◽  
Author(s):  
Richard B. Peterson
Keyword(s):  
Heat Transfer ◽  
Scaling Laws ◽  
Critical Role ◽  
Heat Engine ◽  
Engine Performance ◽  
Characteristic Size ◽  
Operating Efficiency ◽  
Simple Scaling ◽  
Small Structure ◽  
Micro Heat Engine

Abstract Richard P. Feynman introduced the field of microscale and nanoscale engineering in 1959 by giving a talk on how to make things very small. Feynman’s premise was that no fundamental physical laws limit the size of a machine down to the microscopic level. Is this true for all types of machines? Are micro thermal devices fundamentally different than mechanically-based machines with respect to their scaling laws? This paper demonstrates that micro thermal engines do indeed suffer serious performance degradation as their characteristic size is reduced. A micro thermal engine, and more generally, any thermally-based micro device, depends on establishing a temperature difference between two regions within a small structure. In this paper, the performance of a micro thermal engine is explored as a function of the characteristic length parameter, L. In the development, the important features of thermal engines are discussed in the context of developing simple scaling laws predicting the dependency of the operating efficiency on L. After this is accomplished, a general model is derived for a heat engine operating between two temperature reservoirs and having both intrinsic and extrinsic sources of irreversibility, i.e. thermal conductances and heat leakage paths for the heat flow. With this model and typical numerical values for the conductances, micro heat engine performance is predicted as the characteristic size is reduced. This paper demonstrates that under at least one particular formulation of the problem, there may indeed be some room at the bottom. However, heat transfer does play a critical role in determining micro engine performance and depending on how the heat transfer through the engine is modeled, vanishingly small efficiencies can result as the characteristic engine size goes to zero.

scholarly journals Rising obstacle in a one-layer granular bed induced by continuous vibrations: two dynamical regimes governed by vibration velocity

Soft Matter ◽  
2020 ◽  
Vol 16 (37) ◽  
pp. 8612-8617
Author(s):  
Hui Zee Then ◽  
Teruyo Sekiguchi ◽  
Ko Okumura
Keyword(s):  
Scaling Laws ◽  
Vibration Velocity ◽  
Granular Bed ◽  
Simple Scaling ◽  
Dynamical Regimes

We investigate the rising motion of an obstacle in a vertically positioned one-layer granular bed under continuous vibrations, and find that the rising motion is composed of two distinct regimes well characterized by simple scaling laws.

Hydrodynamic interactions for the measurement of thin film elastic properties

2011 ◽  
Vol 674 ◽  
pp. 389-407 ◽  
Author(s):  
S. LEROY ◽  
E. CHARLAIX
Keyword(s):  
Elastic Moduli ◽  
Scaling Laws ◽  
Surface Forces ◽  
Force Response ◽  
Elastic Surface ◽  
Dynamic Surface ◽  
Force Microscopy ◽  
Atomic Force ◽  
Experimental Parameters ◽  
Simple Scaling

We study the elasto-hydrodynamic (EHD) interaction of a sphere with a flat elastic surface in the prospect of measuring the elastic moduli of soft supported thin films, with non-contact dynamic surface forces or atomic force microscopy measurements. When the sphere is oscillated at a very small amplitude close to the surface, the linear force response undergoes a dynamic transition from a viscous-dominated behaviour at large distance to an elastic-dominated behaviour at short distance. In the limit of very thin or very thick supported layers, we show that the force response obeys simple scaling laws which allow to unambiguously determine the absolute elastic modulus of the layer. In the general case, we establish the very rich phase diagram of the EHD interaction and discuss its application for optimizing experimental parameters.

Spectral laser damage testing of optical materials

2017 ◽  
Vol 6 (5) ◽  
Author(s):  
Sven Schröder ◽  
Méabh Garrick ◽  
Anne-Sophie Munser ◽  
Marcus Trost
Keyword(s):  
Scaling Laws ◽  
Near Infrared ◽  
Damage Threshold ◽  
Testing Procedure ◽  
Laser Source ◽  
Spectral Variation ◽  
Significant Drop ◽  
New Instrument ◽  
Simple Scaling ◽  
Laser Induced Damage

AbstractThe spectral laser-induced damage of optical components was measured using a new instrument based on combining a laser-induced damage threshold (LIDT) testing procedure with angle-resolved light scattering and using a tunable optical parametric oscillator laser source. Tests on aluminum mirrors revealed a significant drop of the LIDT around 800 nm, which is not predicted by simple scaling laws. For near-infrared edge filters, remarkable changes in the LIDT around the band edge were observed, which are linked to the spectral variation of the field distribution in the interference coating.

scholarly journals Contact area of rough spheres: Large scale simulations and simple scaling laws

2016 ◽  
Vol 108 (22) ◽  
pp. 221601 ◽  
Author(s):  
Lars Pastewka ◽  
Mark O. Robbins
Keyword(s):  
Contact Area ◽  
Large Scale ◽  
Scaling Laws ◽  
Simple Scaling ◽  
Large Scale Simulations
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