MD Simulations of Nano-Scale Gas Flows: A Case Study of Couette Flow at Kn = 10

2011 ◽  
Author(s):  
M. Barisik ◽  
A. Beskok
Keyword(s):  
Couette Flow ◽  
Md Simulations ◽  
Gas Flows ◽  
Nano Scale

A Case Study of Defects Due to Process-Design Interaction in Nano Scale Technology

2007 ◽  
Author(s):  
Hung-Sung Lin ◽  
Ying-Chin Hou ◽  
Juimei Fu ◽  
Mong-Sheng Wu ◽  
Vincent Huang ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Circuit Design ◽  
Process Design ◽  
Integrated Circuit ◽  
Photon Emission ◽  
Integrated Circuit Design ◽  
Nano Scale ◽  
Leakage Path ◽  
Related Defect

Abstract The difficulties in identifying the precise defect location and real leakage path is increasing as the integrated circuit design and process have become more and more complicated in nano scale technology node. Most of the defects causing chip leakage are detectable with only one of the FA (Failure Analysis) tools such as LCD (Liquid Crystal Detection) or PEM (Photon Emission Microscope). However, due to marginality of process-design interaction some defects are often not detectable with only one FA tool [1][2]. This paper present an example of an abnormal power consumption process-design interaction related defect which could only be detected with more advanced FA tools.

scholarly journals Bacterial Outer Membrane Vesicles as Nano‐Scale Bioreactors: A Fatty Acid Conversion Case Study

ChemCatChem ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 4080-4086
Author(s):  
Ji‐Won Song ◽  
Yoonjin Baeg ◽  
Ha‐Yeon Jeong ◽  
Jinwon Lee ◽  
Deok‐Kun Oh ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Outer Membrane ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Nano Scale ◽  
Bacterial Outer Membrane

scholarly journals Decomposition of the temporal growth rate in linear instability of compressible gas flows

2015 ◽  
Vol 778 ◽  
pp. 120-132 ◽  
Author(s):  
Mario Weder ◽  
Michael Gloor ◽  
Leonhard Kleiser
Keyword(s):  
Growth Rate ◽  
Energy Balance ◽  
Linear Stability ◽  
Couette Flow ◽  
Stability Theory ◽  
Compressible Flows ◽  
Linear Instability ◽  
Linear Stability Theory ◽  
Gas Flows ◽  
Temporal Growth Rate

We present a decomposition of the temporal growth rate ${\it\omega}_{i}$ which characterises the evolution of wave-like disturbances in linear stability theory for compressible flows. The decomposition is based on the disturbance energy balance by Chu (Acta Mech., vol. 1 (3), 1965, pp. 215–234) and provides terms for production, dissipation and flux of energy as components of ${\it\omega}_{i}$. The inclusion of flux terms makes our formulation applicable to unconfined flows and flows with permeable or vibrating boundaries. The decomposition sheds light on the fundamental mechanisms determining temporal growth or decay of disturbances. The additional insights gained by the proposed approach are demonstrated by an investigation of two model flows, namely compressible Couette flow and a plane compressible jet.

Smoothed particles as a non-Newtonian fluid: A case study in Couette flow

2010 ◽  
Vol 65 (6) ◽  
pp. 2258-2262 ◽  
Author(s):  
Guangzheng Zhou ◽  
Wei Ge ◽  
Jinghai Li
Keyword(s):  
Couette Flow ◽  
Newtonian Fluid

Size dependence and stochastic nature of yield strength of micron-sized crystals: a case study on Ni 3 Al

2006 ◽  
Vol 462 (2070) ◽  
pp. 1661-1681 ◽  
Author(s):  
A.H.W Ngan ◽  
L Zuo ◽  
P.C Wo
Keyword(s):  
Strong Dependence ◽  
Md Simulations ◽  
Al Alloy ◽  
Dislocation Generation ◽  
Embedded Atom ◽  
Incipient Plasticity ◽  
Material Volume ◽  
General Material ◽  
Atom Potential

Recent experiments indicate that the first yield point of micron-sized metals exhibits significant statistical scatter as well as strong dependence on the specimen size. In this work, molecular dynamics (MD) simulations are carried out to investigate the onset of shear deformation in a small block of material, using an embedded atom potential for the intermetallic Ni 3 Al alloy. Incipient plasticity in the form of homogeneous dislocation generation is observed to occur at atomic sites with interatomic displacements approaching one-half of the Shockley partial Burgers vector. From the distribution function of the interatomic displacements observed in the MD simulations, the probability of a general material volume surviving under given loading conditions is predicted. The survival probability is then calculated for several situations, including homogeneous deformation and nanoindentation, to predict the critical load for incipient plasticity to occur in these situations. The predicted results are compared to micro-pillar compression and nanoindentation experiments on Ni 3 Al available in the literature.

Multiscale Study of Gas Slip Flows in Nanochannels

2015 ◽  
Vol 137 (9) ◽  
Author(s):  
Quy Dong To ◽  
Thanh Tung Pham ◽  
Vincent Brites ◽  
Céline Léonard ◽  
Guy Lauriat
Keyword(s):  
Density Functional ◽  
Interaction Model ◽  
Maxwell Model ◽  
Theoretical Models ◽  
Md Simulations ◽  
Gas Flows ◽  
Simulation And Modeling ◽  
Slip Effects ◽  
Accommodation Coefficients ◽  
Ar Gas

A multiscale modeling of the anisotropic slip phenomenon for gas flows is presented in a tree-step approach: determination of the gas–wall potential, simulation and modeling of the gas–wall collisions, simulation and modeling of the anisotropic slip effects. The density functional theory (DFT) is used to examine the interaction between the Pt–Ar gas–wall couple. This potential is then passed into molecular dynamics (MD) simulations of beam scattering experiments in order to calculate accommodation coefficients. These coefficients enter in an effective gas–wall interaction model, which is the base of efficient MD simulations of gas flows between anisotropic surfaces. The slip effects are quantified numerically and compared with simplified theoretical models derived in this paper. The paper demonstrates that the DFT potential is in good agreement with empirical potentials and that an extension of the Maxwell model can describe anisotropic slip effects due to surface roughness, provided that two tangential accommodation parameters are introduced. MD data show excellent agreement with the tensorial slip theory, except at large Kundsen numbers (for example, Kn ≃0.2) and with an analytical expression which predicts the ratio between transverse and longitudinal slip velocity components.

Nano-Droplet Impingement Heat Transfer on a Solid Surface

2010 ◽  
Author(s):  
Geoffrey Haas ◽  
Aaron P. Wemhoff
Keyword(s):  
Solid Surface ◽  
Md Simulations ◽  
Maximum Efficiency ◽  
Attractive Alternative ◽  
Droplet Impingement ◽  
Nano Scale ◽  
Simulation Techniques ◽  
Impingement Heat Transfer ◽  
Alternative Approach ◽  
Cooling Methods

The reduction of electronic components towards the nano-scale drives the development of novel cooling methods to keep up with the increasing thermal demands of the electronics industry. Since transistor dimensions are shrinking to the order of 1–10 nm, pinpointed cooling may be required for maximum efficiency. Many nano-scale cooling methods are difficult to observe in direct experimentation, so simulation techniques present an attractive alternative approach. In this respect, molecular dynamics (MD) simulations of nano-droplet impingement on a solid surface is being investigated as a potential means for pinpointed cooling. Various observations of thermophysical phenomena associated with the impingement are discussed, including the temperature rise at the collision point, the acceleration of the droplet prior to impact, and and the ordering of molecules in the liquid due to the influence of the solid.

Case Study of Dynamic Simulation

2006 ◽  
Author(s):  
Vasily Bulatov ◽  
Wei Cai
Keyword(s):  
Energy Minimization ◽  
Initial Conditions ◽  
Dislocation Core ◽  
Md Simulations ◽  
Dislocation Motion ◽  
Displacement Fields ◽  
Direct Observations ◽  
Elasticity Solutions

The preceding chapter focused on the dislocation core structure at zero temperature obtained by energy minimization. In this chapter we will discuss a case study of dislocation motion at finite temperature by molecular dynamics (MD) simulations. MD simulations offer unique insights into the mechanistic and quantitative aspects of dislocation mobility because accurate measurements of dislocation velocity are generally difficult, and direct observations of dislocation motion in full atomistic detail are still impossible. The discussion of this case study is complete in terms of relevant details, including boundary and initial conditions, temperature and stress control, and, finally, visualization and data analysis. In Section 3.1 we discussed a method for introducing a dislocation into a simulation cell. It relies on the linear elasticity solutions for dislocation displacement fields. To expand our repertoire, let us try another method here. The idea is to create a planar misfit interface between two crystals, such that subsequent energy minimization would automatically lead to dislocation formation.

Molecular Dynamics Simulations of Thermal Interactions in Nanoscale Liquid Channels

2008 ◽  
Author(s):  
BoHung Kim ◽  
Ali Beskok ◽  
Tahir Cagin
Keyword(s):  
Molecular Dynamics ◽  
Thermal Resistance ◽  
Md Simulations ◽  
Kapitza Resistance ◽  
Fourier Law ◽  
Thermal Exchange ◽  
Nano Scale ◽  
Thermal Oscillation ◽  
Temperature Jumps ◽  
Dynamics Simulations

Molecular Dynamics (MD) simulations of nano-scale flows typically utilize fixed lattice crystal interactions between the fluid and stationary wall molecules. This approach cannot properly model thermal exchange at the wall-fluid interface. Therefore, we use an interactive thermal wall model that can properly simulate the flow and heat transfer in nano-scale channels. Using the interactive thermal wall, Fourier law of heat conduction is verified for the 3.24 nm channel, while the thermal conductivity obtained from Fourier law is verified using the predictions of Green-Kubo theory. Moreover, temperature jumps at the liquid/solid interface, corresponding to the well known Kapitza resistance, are observed. Using systematic studies thermal resistance length at the interface is characterized as a function of the surface wettability, thermal oscillation frequency, wall temperature and thermal gradient. An empirical model for the thermal resistance length, which could be used as the jump-coefficient of a Navier boundary condition, is developed.

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