Cellular Automata Simulations of Thermal Transport Properties of Thin-Film Polymer/CNTs Nano-Composites for Improved Design

2014 ◽  
Vol 1619 ◽  
Author(s):  
P. Kalakonda ◽  
A. Casey ◽  
G. S. Iannacchione ◽  
G. Y. Georgiev ◽  
Y. Cabrera ◽  
...  
Keyword(s):  
Thin Film ◽  
Thermal Conductivity ◽  
Cellular Automata ◽  
Transport Properties ◽  
Thermal Transport ◽  
Film Plane ◽  
Property Relation ◽  
Improved Design ◽  
Film Polymer ◽  
Film Nanocomposites

ABSTRACTA computational algorithm has been developed to simulate the transport properties of oriented and un-oriented thin film nanocomposites of isotactic Polypropylene (iPP) and carbon nanotubes (CNT) with increasing CNT concentration. Our goal is to be able to design materials with optimal properties using these simulations. We use a cellular automata approach in a Matlab 3-D array environment. The percolation threshold is reproduced in the simulations, matching experimental data. Upon percolation, the thermal transport in the films increases sharply, due to the large difference in the thermal conductivities of the CNTs and the polymer. To verify the simulation, the thin-film samples were sheared in the melt at 200C at 1 Hz in a Linkan microscope shearing hot stage. The thermal conductivity measurements were performed on the same cell arrangement with the transport perpendicular to the thin-film plane using a DC method. The thermal conductivity is higher for the un-sheared as compared to the sheared samples. Our cellular automata simulations provide information about the microstructuremacroscopic property relation in the thin film nanocomposites and can be extended to simulations of other important materials.

scholarly journals Study of anisotropic thermal conductivity in textured thermoelectric alloys by Raman spectroscopy

RSC Advances ◽  
2021 ◽  
Vol 11 (39) ◽  
pp. 24456-24465
Author(s):  
Rapaka S. C. Bose ◽  
K. Ramesh
Keyword(s):  
Crystal Structure ◽  
Thermal Conductivity ◽  
Raman Spectroscopy ◽  
Transport Properties ◽  
Thermal Transport ◽  
Layered Crystal ◽  
Layered Crystal Structure ◽  
Thermal Transport Properties ◽  
Anisotropic Thermal Conductivity ◽  
P Type

Polycrystalline p-type Sb1.5Bi0.5Te3 (SBT) and n-type Bi2Te2.7Se0.3 (BTS) compounds possessing layered crystal structure show anisotropic electronic and thermal transport properties.

scholarly journals Thermal transport properties of decagonal quasicrystals and their approximants

2013 ◽  
Vol 1517 ◽  
Author(s):  
Petar Popčević ◽  
Ante Bilušić ◽  
Kristijan Velebit ◽  
Ana Smontara
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Transport Properties ◽  
Heat Transport ◽  
Thermal Transport ◽  
Strong Relationship ◽  
Decagonal Quasicrystal ◽  
Decagonal Quasicrystals ◽  
Plane Anisotropy ◽  
Out Of Plane

ABSTRACTTransport properties (thermal conductivity, electrical resistivity and thermopower) of decagonal quasicrystal d-AlCoNi, and approximant phases Y-AlCoNi, o-Al13Co4, m-Al13Fe4, m-Al13(Fe,Ni)4 and T-AlMnFe have been reviewed. Among all presented alloys the stacking direction (periodic for decagonal quasicrystals) is the most conductive one for the charge and heat transport, and the in/out-of-plane anisotropy is much larger than the in-plane anisotropy. There is a strong relationship between periodicity length along stacking direction and anisotropy of transport properties in both quasicrystals and their approximants suggesting a decrease of the anisotropy with increasing number of stacking layers.

Thermal transport properties of an oriented thin film of a paraffinic tripodal triptycene

2021 ◽  
Vol 60 (3) ◽  
pp. 038002
Author(s):  
Takaki Imaizumi ◽  
Ryosuke Takehara ◽  
Yuichiro Yamashita ◽  
Takashi Yagi ◽  
Fumitaka Ishiwari ◽  
...  
Keyword(s):  
Thin Film ◽  
Transport Properties ◽  
Thermal Transport ◽  
Thermal Transport Properties

Thermal transport properties of monolayer MoSe2 with defects

2020 ◽  
Vol 22 (10) ◽  
pp. 5832-5838 ◽  
Author(s):  
Jiang-Jiang Ma ◽  
Jing-Jing Zheng ◽  
Wei-Dong Li ◽  
Dong-Hong Wang ◽  
Bao-Tian Wang
Keyword(s):  
Thermal Conductivity ◽  
Transport Properties ◽  
Thermal Transport ◽  
Lattice Thermal Conductivity ◽  
Thermal Transport Properties

The defects in monolayer MoSe2 have a significant effect on its lattice thermal conductivity.

scholarly journals Reduction of Lattice Thermal Conductivity in PbTe Induced by Artificially Generated Pores

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Jae-Yeol Hwang ◽  
Eun Sung Kim ◽  
Syed Waqar Hasan ◽  
Soon-Mok Choi ◽  
Kyu Hyoung Lee ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Pore Structure ◽  
Transport Properties ◽  
Thermoelectric Materials ◽  
Thermal Transport ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Phonon Modes ◽  
Thermal Transport Properties

Highly dense pore structure was generated by simple sequential routes using NaCl and PVA as porogens in conventional PbTe thermoelectric materials, and the effect of pores on thermal transport properties was investigated. Compared with the pristine PbTe, the lattice thermal conductivity values of pore-generated PbTe polycrystalline bulks were significantly reduced due to the enhanced phonon scattering by mismatched phonon modes in the presence of pores (200 nm–2 μm) in the PbTe matrix. We obtained extremely low lattice thermal conductivity (~0.56 W m−1 K−1at 773 K) in pore-embedded PbTe bulk after sonication for the elimination of NaCl residue.

Annealing Studies of Re Doped AlPdMn Quasicrystals

2001 ◽  
Vol 691 ◽  
Author(s):  
Donny W. Winkler ◽  
Terry M. Tritt ◽  
Robert Gagnon ◽  
J. Strom-Olsen
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Transport Properties ◽  
Thermal Transport ◽  
Amorphous Materials ◽  
Annealed Sample ◽  
Annealing Conditions ◽  
Thermal Transport Properties ◽  
The Relationship

ABSTRACTQuasicrystals have properties associated with both crystalline and amorphous materials. These properties appear to be sensitive to both composition and annealing conditions. Therefore, it is important to investigate the influence of the microstructure on the electrical and thermal transport properties of quasicrystals. AlPdMn quasicrystal samples were prepared with various levels of Re substituted for the Mn (Al70Pd20Mn10−XReX) and then subjected to different annealing conditions. Electrical resistivity, thermopower and thermal conductivity were measured on each as grown and annealed sample over a broad range of temperature, 10 K < T < 300 K. The relationship between the electrical and thermal transport properties and microstructure will be presented and discussed.

Evidence of a Order-Disorder Transition in the Crystalline Phase of Cd6Yb, 1/1 cubic approximant of icosahedral Cd 5.7 Yb

2003 ◽  
Vol 793 ◽  
Author(s):  
N. Sorloaica ◽  
A. L. Pope ◽  
D. W. Winkler ◽  
Terry M. Tritt ◽  
V. Keppens ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Temperature Dependence ◽  
Transport Properties ◽  
Crystalline Phase ◽  
Thermal Transport ◽  
Hysteretic Behavior ◽  
Disorder Transition ◽  
Temperature Range ◽  
Thermal Transport Properties

ABSTRACTThe electrical and thermal transport properties (electrical resistivity, thermopower, heat capacity and thermal conductivity) of the crystalline phase of the binary Cd6Yb system has been measured over a temperature range from 10 K to 300 K. Evidence for a phase transition in Cd6Yb is observed in the electrical transport properties with distinct changes in the temperature dependence of the resistivity and thermopower around T ≈ 110K. An anomaly in the heat capacity and a thermal conductivity is also observed at this same temperature. Hysteretic behavior is not evident in the temperature dependence of any of the electrical and thermal transport properties. In addition, the elastic properties using resonant ultrasound (RUS) techniques have been investigated over a similar temperature range. A large “resonance dip” is observed in the RUS data at T ≈ 110K, which is indicative of some type of structural change in the crystalline material at this temperature. These data will be presented and discussed in context of the undergoes reversible order-disorder transition in the 1/1 cubic approximant at about 110 K, which makes the system very interesting compared to the quasicrystal phase Cd5.7Yb

Thermal Transport Properties of Various Thin Films for MEMS Applications

2006 ◽  
Vol 326-328 ◽  
pp. 293-296
Author(s):  
Sun Rock Choi ◽  
Dong Sik Kim ◽  
Sung Hoon Choa
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Transport Properties ◽  
Thermal Transport ◽  
Metallic Thin Films ◽  
Micro Electro Mechanical Systems ◽  
Thermal Transport Properties ◽  
Atomic Force Microscope Measurement ◽  
Evaporation Technique ◽  
Thermal Diffusivities

The thermal properties of thin films, such as thermal conductivity and diffusivity, are important in design and analysis of MEMS (micro electro mechanical systems), particularly in microscale thermal systems and high-power electronic/optoelectronic devices. In the present study, the thermal conductivity and diffusivity of a variety of thin film materials, which are commonly used in MEMS applications, are measured. The samples include Au, Sn, Mo, Al/Ti alloy, AlN, and SiC. The Au sample is deposited by the e-beam evaporation technique while the rest of the metallic samples are deposited by sputtering processes. The AlN and SiC films are also prepared by sputtering processes. In the experiment, the thermal diffusivities of metallic thin films are measured by two independent methods — the AC calorimetric method and photothermal mirage technique. The thermal conductivities of dielectric thin films are measured by the 3 omega technique. The results show that the thermal transport properties of some of the films are significantly smaller than those of the same material in bulk form. Especially, the AlN and SiC thin films exhibit pronounced thermal conductivity reduction because of the size effect. The electrical conductivities of the metallic thin films are measured as well. The results for Au and Sn are consistent with the thermal conductivity, confirming the Wiedmann-Franz law. However, Al/Ti and Mo thin films show considerable deviation from the law. The results are analyzed based on the XRD (X-Ray diffraction) and AFM (Atomic Force Microscope) measurement.

scholarly journals Effect of magnetic field on the charge and thermal transport properties of hot and dense QCD matter

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Shubhalaxmi Rath ◽  
Binoy Krishna Patra
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Transport Properties ◽  
Strong Magnetic Field ◽  
Knudsen Number ◽  
Thermal Transport ◽  
Isotropic Medium ◽  
Chemical Potential ◽  
Lorenz Number

Abstract We have studied the effect of strong magnetic field on the charge and thermal transport properties of hot QCD matter at finite chemical potential. For this purpose, we have calculated the electrical conductivity ($$\sigma _\mathrm{el}$$σel) and the thermal conductivity ($$\kappa $$κ) using kinetic theory in the relaxation time approximation, where the interactions are subsumed through the distribution functions within the quasiparticle model at finite temperature, strong magnetic field and finite chemical potential. This study helps to understand the impacts of strong magnetic field and chemical potential on the local equilibrium by the Knudsen number ($$\Omega $$Ω) through $$\kappa $$κ and on the relative behavior between thermal conductivity and electrical conductivity through the Lorenz number (L) in the Wiedemann–Franz law. We have observed that, both $$\sigma _\mathrm{el}$$σel and $$\kappa $$κ get increased in the presence of strong magnetic field, and the additional presence of chemical potential further increases their magnitudes, where $$\sigma _\mathrm{el}$$σel shows decreasing trend with the temperature, opposite to its increasing behavior in the isotropic medium, whereas $$\kappa $$κ increases slowly with the temperature, contrary to its fast increase in the isotropic medium. The variation in $$\kappa $$κ explains the decrease of the Knudsen number with the increase of the temperature. However, in the presence of strong magnetic field and finite chemical potential, $$\Omega $$Ω gets enhanced and approaches unity, thus, the system may move slightly away from the equilibrium state. The Lorenz number ($$\kappa /(\sigma _\mathrm{el} T))$$κ/(σelT)) in the abovementioned regime of strong magnetic field and finite chemical potential shows linear enhancement with the temperature and has smaller magnitude than the isotropic one, thus, it describes the violation of the Wiedemann–Franz law for the hot and dense QCD matter in the presence of a strong magnetic field.

scholarly journals Impact of screw and edge dislocations on the thermal conductivity of individual nanowires and bulk GaN: a molecular dynamics study

2018 ◽  
Vol 20 (7) ◽  
pp. 5159-5172 ◽  
Author(s):  
Konstantinos Termentzidis ◽  
Mykola Isaiev ◽  
Anastasiia Salnikova ◽  
Imad Belabbas ◽  
David Lacroix ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Transport Properties ◽  
Thermal Transport ◽  
Thermal Transport Properties ◽  
Bulk Gan ◽  
Dynamics Simulations ◽  
Edge Dislocations

The thermal transport properties of nanowires and bulk GaN in the presence of different dislocations using molecular dynamics simulations are reported.

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