scholarly journals General constitutive equations of heat transport at small length scales and high frequencies with extension to mass and electrical charge transport

2016 ◽  
Vol 52 ◽  
pp. 30-37 ◽  
Author(s):  
Hatim Machrafi ◽  
Georgy Lebon
Keyword(s):  
Charge Transport ◽  
Heat Transport ◽  
Constitutive Equations ◽  
Electrical Charge ◽  
Small Length ◽  
Length Scales ◽  
High Frequencies

scholarly journals Robust Calorimetric Micro-Sensor for Aerodynamic Applications

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 794
Author(s):  
Cécile Ghouila-Houri ◽  
Célestin Ott ◽  
Romain Viard ◽  
Quentin Gallas ◽  
Eric Garnier ◽  
...  
Keyword(s):  
Shear Stress ◽  
Flow Control ◽  
Flow Separation ◽  
Active Flow Control ◽  
Small Length ◽  
High Frequencies ◽  
Small Length Scale ◽  
Micro Sensor ◽  
Active Flow

This paper reports a calorimetric micro-sensor designed for aerodynamic applications. Measuring both the amplitude and the sign of the wall shear stress at small length-scale and high frequencies, the micro-sensor is particularly suited for flow separation detection and flow control. The micro-sensor was calibrated in static and dynamic in a turbulent boundary layer wind tunnel. Several micro-sensors were embedded in various configurations for measuring the shear stress and detecting flow separation. Specially, one was embedded inside an actuator slot for in situ measurements and twelve, associated with miniaturized electronics, were implemented on a flap model for active flow control experiments.

scholarly journals Spin-charge separation at small length scales in the 2D t-J Model

1995 ◽  
Vol 99 (3-4) ◽  
pp. 509-511
Author(s):  
Roser Valent� ◽  
Claudius Gros
Keyword(s):  
Charge Separation ◽  
Small Length ◽  
Length Scales

scholarly journals Transmission x-ray microscopy at low temperatures: Irregular supercurrent flow at small length scales

2018 ◽  
Vol 97 (13) ◽  
Author(s):  
J. Simmendinger ◽  
S. Ruoss ◽  
C. Stahl ◽  
M. Weigand ◽  
J. Gräfe ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Small Length ◽  
Length Scales ◽  
X Ray

High-Frequency Seismic Wave Propagation in Northeastern North America

1990 ◽  
Vol 61 (3-4) ◽  
pp. 193-208 ◽  
Author(s):  
S. E. Hough ◽  
K. H. Jacob ◽  
L. Seeber
Keyword(s):  
North America ◽  
High Frequency ◽  
Characteristic Length ◽  
Body Waves ◽  
Eastern North America ◽  
Western North America ◽  
Energy Propagation ◽  
Length Scales ◽  
Near Surface ◽  
High Frequencies

Abstract A key element in the assessment of seismic hazard is the estimation of how energy propagation from a given earthquake is affected by crustal structure near the receiver and along the more distant propagation path. In this paper, we present data from a variety of sources in eastern North America recorded at epicentral distances of a few to 800 km, and characterize and interpret systematic features. Site effects have been classically considered in terms of amplification either within a sediment-filled valley or from a single topographic feature (Geli et al., 1988). We present evidence of high frequency (5–30 Hz) resonances observed in hard-rock recordings of both body waves and Lg waves, and suggest that site effect should be expanded regionally to include structural and topographic information over sufficiently large areas to include several wavelengths of any features that may interact with seismic waves in the frequency range of interest. A growing body of evidence suggests that ground motions at high frequencies recorded at large epicentral distances in eastern North America are controlled by resonance effects. We hypothesize that a fundamental difference between eastern and western North America spectra stems from a combination of differences in the character of topography and near-surface structure. Active tectonics of western North America gives rise to a complex crust that scatters seismic energy in a random manner and results in very effective attenuation of high frequencies. The older eastern North American crust contains scatterers that are more ordered, with characteristic length scales that give rise to resonance phenomena in the frequency band critical for earthquake hazard. We present preliminary analysis of topographic data from the Adirondack Mountains in New York that demonstrates the existence of characteristic length scales on the order of up to 1–3 kilometers. Features with these length scales will effectively scatter energy at frequencies in the 1 to 10 Hz range.

THREE-DIMENSIONAL PHONON TRANSPORT SIMULATION FOR NANO/MICROSTRUCTURED MATERIALS

2008 ◽  
Vol 07 (02n03) ◽  
pp. 103-112 ◽  
Author(s):  
A. SAKURAI ◽  
S. MARUYAMA ◽  
A. KOMIYA ◽  
K. MIYAZAKI
Keyword(s):  
Radiative Transfer ◽  
Heat Transport ◽  
Characteristic Length ◽  
Transport Phenomena ◽  
Three Dimensional ◽  
Phonon Transport ◽  
Discrete Ordinates ◽  
Complex Geometries ◽  
Transport Mechanisms ◽  
Length Scales

The Discrete Ordinates Radiation Element Method (DOREM), which is radiative transfer code, is applied for solving phonon transport of nano/microscale materials. The DOREM allows phonon simulation with multi-dimensional complex geometries. The objective of this study is to apply the DOREM to the nano/microstructured materials. It is confirmed that significant changes of the heat transport phenomena with different characteristic length scales and geometries are observed. This study also discusses further variations for understanding of heat transport mechanisms.

Vibration Characteristics of Multiwalled Carbon Nanotubes Embedded in Elastic Media by a Nonlocal Elastic Shell Model

2007 ◽  
Vol 74 (6) ◽  
pp. 1087-1094 ◽  
Author(s):  
Renfu Li ◽  
George A. Kardomateas
Keyword(s):  
Carbon Nanotubes ◽  
Shell Model ◽  
Multiwalled Carbon Nanotubes ◽  
Van Der Waals ◽  
Van Der Waals Forces ◽  
Elastic Media ◽  
Small Length ◽  
Multiwalled Carbon ◽  
Resonant Frequencies ◽  
Length Scales

In this paper, the vibrational behavior of the multiwalled carbon nanotubes (MWCNTs) embedded in elastic media is investigated by a nonlocal shell model. The nonlocal shell model is formulated by considering the small length scales effects, the interaction of van der Waals forces between two adjacent tubes and the reaction from the surrounding media, and a set of governing equations of motion for the MWCNTs are accordingly derived. In contrast to the beam models in the literature, which would only predict the resonant frequencies of bending vibrational modes by taking the MWCNT as a whole beam, the current shell model can find the resonant frequencies of three modes being classified as radial, axial, and circumferential for each nanotube of a MWCNT. Big influences from the small length scales and the van der Waals’ forces are observed. Among these, noteworthy is the reduction in the radial frequencies due to the van der Waals’ force interaction between two adjacent nanotubes. The numerical results also show that when the spring constant k0 of the surrounding elastic medium reaches a certain value, the lowest resonant frequency of the double walled carbon nanotube drops dramatically.

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