Modeling the Phonon Transport in Nanowire with Different Cross-Section

The phonon transport in silicon nanowire was simulated by Monte Carlo Method (MCM). The effect on the phonon transport of the boundary reflection mode, cross-section size and cross-section shape was studied. Analysis shows that diffuse reflection can result in phonon accumulation at the circumferential boundary. As the cross-section size decrease, the nonuniformity of the temperature distribution within the cross-section becomes more severe. When the area of the square cross-section silicon nanowire (SCSN) is equal to that of the circular cross-section silicon nanowire (CCSN), the thermal conductivity of them is more close to each other.

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Stochastic Thermal Properties of Laminates Filled with Long Fibers

Materials ◽

10.3390/ma14102511 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2511

Author(s):

Jan Turant

Keyword(s):

Thermal Conductivity ◽

Effective Thermal Conductivity ◽

Cross Section ◽

Circular Cross Section ◽

Saturation Density ◽

Composite Matrix ◽

Number Of Layers ◽

Stochastic Parameters ◽

Multilayer Composites ◽

Long Fibers

In this paper, the stochastic parameters of the effective thermal conductivity of multilayer composites are considered. The examined specimens of composites were built with a different number of layers and each had a different saturation density of a composite matrix with fibers. For each case of laminate built with a prescribed number of layers and assumed saturation density, 10,000 tests of its effective thermal conductivity were carried out using numerical experiments. It was assumed that the fibers located in each layer were rectilinear, had a circular cross-section and that they could take random positions in their repeatable volume elements (RVEs). In view of the mentioned assumptions, the heat flux passing throughout a cross-section of a composite sample, perpendicular to the fibers’ direction, was considered. The probability density functions were fitted to the obtained data and then the chosen stochastic parameters of the effective thermal conductivity coefficients were determined.

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Designing for People’s Safety on Flooded Streets: Uncertainties and the Influence of the Cross-Section Shape, Roughness and Slopes on Hazard Criteria

Water ◽

10.3390/w13152119 ◽

2021 ◽

Vol 13 (15) ◽

pp. 2119

Author(s):

Luís Mesquita David ◽

Rita Fernandes de Carvalho

Keyword(s):

Cross Section ◽

Overland Flow ◽

Rectangular Cross Section ◽

Safety Hazard ◽

Cross Section Shape ◽

Section Shape ◽

Flood Flows ◽

The Cross ◽

Flooding Risk

Designing for exceedance events consists in designing a continuous route for overland flow to deal with flows exceeding the sewer system’s capacity and to mitigate flooding risk. A review is carried out here on flood safety/hazard criteria, which generally establish thresholds for the water depth and flood velocity, or a relationship between them. The effects of the cross-section shape, roughness and slope of streets in meeting the criteria are evaluated based on equations, graphical results and one case study. An expedited method for the verification of safety criteria based solely on flow is presented, saving efforts in detailing models and increasing confidence in the results from simplified models. The method is valid for 0.1 m2/s 0.5 m2/s. The results showed that a street with a 1.8% slope, 75 m1/3s−1 and a rectangular cross-section complies with the threshold 0.3 m2/s for twice the flow of a street with the same width but with a conventional cross-section shape. The flow will be four times greater for a 15% street slope. The results also highlighted that the flood flows can vary significantly along the streets depending on the sewers’ roughness and the flow transfers between the major and minor systems, such that the effort detailing a street’s cross-section must be balanced with all of the other sources of uncertainty.

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Asymptotic Behavior of Stable Structures Made of Beams

Journal of Elasticity ◽

10.1007/s10659-021-09816-w ◽

2021 ◽

Author(s):

Georges Griso ◽

Larysa Khilkova ◽

Julia Orlik ◽

Olena Sivak

Keyword(s):

Asymptotic Behavior ◽

Cross Section ◽

Cross Sections ◽

Linear Elasticity ◽

Circular Cross Section ◽

Linear Elasticity Theory ◽

Linear Elastic ◽

The Cross ◽

Small Rotation ◽

Stable Structures

AbstractIn this paper, we study the asymptotic behavior of an $\varepsilon $ ε -periodic 3D stable structure made of beams of circular cross-section of radius $r$ r when the periodicity parameter $\varepsilon $ ε and the ratio ${r/\varepsilon }$ r / ε simultaneously tend to 0. The analysis is performed within the frame of linear elasticity theory and it is based on the known decomposition of the beam displacements into a beam centerline displacement, a small rotation of the cross-sections and a warping (the deformation of the cross-sections). This decomposition allows to obtain Korn type inequalities. We introduce two unfolding operators, one for the homogenization of the set of beam centerlines and another for the dimension reduction of the beams. The limit homogenized problem is still a linear elastic, second order PDE.

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Validation of Welding Simulations Using Thermal Strains Measured with DIC

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.70.129 ◽

2011 ◽

Vol 70 ◽

pp. 129-134 ◽

Cited By ~ 2

Author(s):

Maarten De Strycker ◽

Pascal Lava ◽

Wim Van Paepegem ◽

Luc Schueremans ◽

Dimitri Debruyne

Keyword(s):

Residual Stresses ◽

Cross Section ◽

Circular Cross Section ◽

Welding Process ◽

Weld Bead ◽

Image Correlation ◽

Steel Tubes ◽

Element Analysis ◽

Strain Evolution ◽

The Cross

Residual stresses can affect the performance of steel tubes in many ways and as a result their magnitude and distribution is of particular interest to many applications. Residual stresses in cold-rolled steel tubes mainly originate from the rolling of a flat plate into a circular cross section (involving plastic deformations) and the weld bead that closes the cross section (involving non-uniform heating and cooling). Focus in this contribution is on the longitudinal weld bead that closes the cross section. To reveal the residual stresses in the tubes under consideration, a finite element analysis (FEA) of the welding step in the production process is made. The FEA of the welding process is validated with the temperature evolution of the thermal simulation and the strain evolution for the mechanical part of the analysis. Several methods for measuring the strain evolution are available and in this contribution it is investigated if the Digital Image Correlation (DIC) technique can record the strain evolution during welding. It is shown that the strain evolution obtained with DIC is in agreement with that found by electrical resistance strain gauges. The results of these experimental measuring methods are compared with numerical results from a FEA of the welding process.

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Oxidation of Suspended Stacked Silicon Nanowire for Sub-10nm Cross-Section Shape Optimization

ECS Transactions ◽

10.1149/1.2911500 ◽

2019 ◽

Vol 13 (1) ◽

pp. 195-199 ◽

Cited By ~ 14

Author(s):

Alexandre Hubert ◽

Jean-Philippe Colonna ◽

Stéphane Bécu ◽

Cécilia Dupré ◽

Virginie Maffini-Alvaro ◽

...

Keyword(s):

Shape Optimization ◽

Cross Section ◽

Silicon Nanowire ◽

Cross Section Shape ◽

Section Shape

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Finite-size analysis and the influence of the cross-section shape of the granular column collapses

10.5194/egusphere-egu21-1647 ◽

2021 ◽

Author(s):

Teng Man ◽

Herbert Huppert ◽

Ling Li ◽

Sergio Galindo-Torres

Keyword(s):

Size Effect ◽

Cross Section ◽

Finite Size ◽

Size Analysis ◽

Cross Section Shape ◽

Section Shape ◽

The Cross ◽

Shape Influence ◽

Deposition Morphology ◽

Granular Column

<p>The collapse of granular columns, which sheds light on the kinematics, dynamics, and deposition morphology of mass-driven flows, is crucial for understanding complex flows in both natural and engineering systems, such as debris flows and landslides. However, our research shows that a strong size effect and cross-section shape influence exist in this test. Thus, it is essential to better understand these effects. In this study, we explore the influence of both relative column sizes and cross-section shapes on the run-out behavior of collapsed granular columns and analyze their influence on the deposition morphology with the discrete element method (DEM) with Voronoi-based spheropolyhedron particles. We link the size effect that occurs in granular column collapse problems to the finite-size scaling functions and investigate the characteristic correlation length associated with the granular column collapses. The collapsing behavior of granular columns with different cross-section shapes is also studied, and we find that particles tend to accumulate in the direction normal to the edge of the cross-section instead of the vertex of it. The differences in the run-out behavior in different directions when the cross-section is no longer a circle can also be explained by the finite-size analysis we have performed in this study. We believe that such a study is crucial for us to better understand how granular material flows, how it deposits, and how to consider the size effect in the rheology of granular flows.</p>

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Thermal conductivity of sandstones from Biot’s coefficient

Geophysics ◽

10.1190/geo2017-0551.1 ◽

2018 ◽

Vol 83 (5) ◽

pp. D173-D185 ◽

Cited By ~ 2

Author(s):

Tobias Orlander ◽

Eirini Adamopoulou ◽

Janus Jerver Asmussen ◽

Adam Andrzej Marczyński ◽

Harald Milsch ◽

...

Keyword(s):

Heat Transfer ◽

Thermal Conductivity ◽

Heat Flow ◽

Cross Section ◽

Geometric Mean ◽

Well Log ◽

Biot’S Coefficient ◽

Model Predictions ◽

The Cross ◽

Rock Texture

Thermal conductivity of rocks is typically measured on core samples and cannot be directly measured from logs. We have developed a method to estimate thermal conductivity from logging data, where the key parameter is rock elasticity. This will be relevant for the subsurface industry. Present models for thermal conductivity are typically based primarily on porosity and are limited by inherent constraints and inadequate characterization of the rock texture and can therefore be inaccurate. Provided known or estimated mineralogy, we have developed a theoretical model for prediction of thermal conductivity with application to sandstones. Input parameters are derived from standard logging campaigns through conventional log interpretation. The model is formulated from a simplified rock cube enclosed in a unit volume, where a 1D heat flow passes through constituents in three parallel heat paths: solid, fluid, and solid-fluid in series. The cross section of each path perpendicular to the heat flow represents the rock texture: (1) The cross section with heat transfer through the solid alone is limited by grain contacts, and it is equal to the area governing the material stiffness and quantified through Biot’s coefficient. (2) The cross section with heat transfer through the fluid alone is equal to the area governing fluid flow in the same direction and quantified by a factor analogous to Kozeny’s factor for permeability. (3) The residual cross section involves the residual constituents in the solid-fluid heat path. By using laboratory data for outcrop sandstones and well-log data from a Triassic sandstone formation in Denmark, we compared measured thermal conductivity with our model predictions as well as to the more conventional porosity-based geometric mean. For outcrop material, we find good agreement with model predictions from our work and with the geometric mean, whereas when using well-log data, our model predictions indicate better agreement.

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