Thermal conductivity of ice polymorphs: a computational study

2018 ◽  
Vol 20 (16) ◽  
pp. 11028-11036
Author(s):  
Irene Iriarte-Carretero ◽  
Miguel A. Gonzalez ◽  
Fernando Bresme
Keyword(s):  
Thermal Conductivity ◽  
State Of The Art ◽  
Computational Study ◽  
Water Models

Testing the accuracy of state of the art water models in predicting the thermal conductivity of ice polymorphs.

Localized vibration and avoided crossing in SrTi11O20 for oxide thermoelectrics with intrinsically low thermal conductivity

2021 ◽  
Author(s):  
Yi Li ◽  
Shinya Yamamoto ◽  
Kaleem Ahmad ◽  
Zeyad Ammar Almutairi ◽  
Koumoto Kunihito ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Chemical Bonding ◽  
State Of The Art ◽  
Electron Conduction ◽  
Low Thermal Conductivity ◽  
Oxide Thermoelectrics ◽  
Avoided Crossing ◽  
Conduction Pathway ◽  
Electron Crystal

Many state-of-the-art thermoelectric alloys achieve phonon glass and electron crystal (PGEC) via chemical bonding hierarchy (CBH), which can provide a rigid network for electron conduction pathway and loosely bonded atoms...

Development of high-insulating materials with aerogel for protective clothing applications – an overview

2021 ◽  
Vol 112 (2) ◽  
pp. 164-172
Author(s):  
Agnieszka Greszta ◽  
Sylwia Krzemińska ◽  
Grażyna Bartkowiak ◽  
Anna Dąbrowska
Keyword(s):  
Thermal Conductivity ◽  
Thermal Insulation ◽  
Protective Clothing ◽  
State Of The Art ◽  
Knitted Fabrics ◽  
Insulating Materials ◽  
Textile Materials ◽  
Wide Range ◽  
Properties Of Materials ◽  
Hot Environments

Abstract Aerogels are ultra-light solids with extremely low thermal conductivity (even lower than air), thanks to which they have a huge potential in a wide range of applications. The purpose of this publication is to present the state-of-the art knowledge of the possibility of using aerogels to increase the thermal insulation properties of clothing materials intended for use in both cold and hot environments. Various methods of aerogels application to textile materials (non-woven, woven and knitted fabrics) are discussed, indicating their advantages and limitations. Numerous research studies confirm that aerogels significantly improve the thermal insulation properties of materials, but due to their delicate and brittle structure and their tendency to dusting, their application still poses considerable problems.

Data-Driven Optimization of Reward-Risk Ratio Measures

2020 ◽  
Author(s):  
Ran Ji ◽  
Miguel A. Lejeune
Keyword(s):  
Optimization Problems ◽  
State Of The Art ◽  
Convergence Property ◽  
Computational Study ◽  
Data Driven ◽  
Mixed Integer ◽  
Finite Convergence ◽  
Integer Nonlinear Programming ◽  
Distributionally Robust ◽  
Risk Ratios

We investigate a class of fractional distributionally robust optimization problems with uncertain probabilities. They consist in the maximization of ambiguous fractional functions representing reward-risk ratios and have a semi-infinite programming epigraphic formulation. We derive a new fully parameterized closed-form to compute a new bound on the size of the Wasserstein ambiguity ball. We design a data-driven reformulation and solution framework. The reformulation phase involves the derivation of the support function of the ambiguity set and the concave conjugate of the ratio function. We design modular bisection algorithms which enjoy the finite convergence property. This class of problems has wide applicability in finance, and we specify new ambiguous portfolio optimization models for the Sharpe and Omega ratios. The computational study shows the applicability and scalability of the framework to solve quickly large, industry-relevant-size problems, which cannot be solved in one day with state-of-the-art mixed-integer nonlinear programming (MINLP) solvers.

Thermal conductivity and the microstructure of state-of-the-art chemical-vapor-deposited (CVD) diamond

1993 ◽  
Vol 2 (5-7) ◽  
pp. 1059-1063 ◽  
Author(s):  
J.E. Graebner ◽  
S. Jin ◽  
G.W. Kammlott ◽  
Y.-H. Wong ◽  
J.A. Herb ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
State Of The Art ◽  
Chemical Vapor ◽  
Cvd Diamond ◽  
Chemical Vapor Deposited

scholarly journals Thermal transport in nanocrystalline Si and SiGe by ab initio based Monte Carlo simulation

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Lina Yang ◽  
Austin J. Minnich
Keyword(s):  
Thermal Conductivity ◽  
Monte Carlo ◽  
Ab Initio ◽  
Grain Boundaries ◽  
Thermal Transport ◽  
Phonon Scattering ◽  
Phonon Dispersion ◽  
Computational Study ◽  
Phonon Transport ◽  
Nanocrystalline Si

Abstract Nanocrystalline thermoelectric materials based on Si have long been of interest because Si is earth-abundant, inexpensive, and non-toxic. However, a poor understanding of phonon grain boundary scattering and its effect on thermal conductivity has impeded efforts to improve the thermoelectric figure of merit. Here, we report an ab-initio based computational study of thermal transport in nanocrystalline Si-based materials using a variance-reduced Monte Carlo method with the full phonon dispersion and intrinsic lifetimes from first-principles as input. By fitting the transmission profile of grain boundaries, we obtain excellent agreement with experimental thermal conductivity of nanocrystalline Si [Wang et al. Nano Letters 11, 2206 (2011)]. Based on these calculations, we examine phonon transport in nanocrystalline SiGe alloys with ab-initio electron-phonon scattering rates. Our calculations show that low energy phonons still transport substantial amounts of heat in these materials, despite scattering by electron-phonon interactions, due to the high transmission of phonons at grain boundaries, and thus improvements in ZT are still possible by disrupting these modes. This work demonstrates the important insights into phonon transport that can be obtained using ab-initio based Monte Carlo simulations in complex nanostructured materials.

Thermal Conductivity of Zn4−xCdxSb3 Solid Solutions

1997 ◽  
Vol 478 ◽  
Author(s):  
T. Caillat ◽  
A. Borshchevsky ◽  
J. -P. Fleurial
Keyword(s):  
Thermal Conductivity ◽  
High Performance ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
State Of The Art ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Jet Propulsion ◽  
P Type ◽  
Electrical Conductors

Abstractβ-Zn4Sb3 was recently identified at the Jet Propulsion Laboratory as a new high performance p-type thermoelectric material with a maximum dimensionless thermoelectric figure of merit ZT of 1.4 at a temperature of 673K. A usual approach, used for many state-of-the-art thermoelectric materials, to further improve ZT values is to alloy β-Zn4Sb3 with isostructural compounds because of the expected decrease in lattice thermal conductivity. We have grown Zn4−xCdxSb3 crystals with 0.2≤x<1.2 and measured their thermal conductivity from 10 to 500K. The thermal conductivity values of Zn4−xCdxSb3 alloys are significantly lower than those measured for β-Zn4Sb3 and are comparable to its calculated minimum thermal conductivity. A strong atomic disorder is believed to be primarily at the origin of the very low thermal conductivity of these materials which are also fairly good electrical conductors and are therefore excellent candidates for thermoelectric applications.

Rational design of novel fluorescent analogues of cholesterol: a “step-by-step” computational study

2019 ◽  
Vol 21 (28) ◽  
pp. 15487-15503 ◽  
Author(s):  
Andrea Bonvicini ◽  
Peter Reinholdt ◽  
Vincent Tognetti ◽  
Laurent Joubert ◽  
Daniel Wüstner ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Quantum Chemical ◽  
Rational Design ◽  
State Of The Art ◽  
Computational Study ◽  
Dynamics Simulations ◽  
Fluorescent Analogues

State-of-the-art quantum chemical and molecular dynamics simulations are used as guidelines in design of novel fluorescent analogues of cholesterol.

Strain engineering and thermal conductivity of a penta-BCN monolayer: a computational study

2021 ◽  
Author(s):  
Klichchupong Dabsamut ◽  
Thanasee Thanasarnsurapong ◽  
Tosapol Maluangnont ◽  
Jiraroj T-Thienprasert ◽  
Sirichok Jungthawan ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Computational Study ◽  
Strain Engineering

Prediction of the Temperature-Dependent Thermal Conductivity and Shear Viscosity for Rigid Water Models

2012 ◽  
Vol 3 (3) ◽  
Author(s):  
Yijin Mao ◽  
Yuwen Zhang
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Shear Viscosity ◽  
Liquid Water ◽  
Nonequilibrium Molecular Dynamics ◽  
Temperature Dependent ◽  
Temperature Range ◽  
Site Model ◽  
Water Models ◽  
Temperature Dependent Thermal Conductivity

The temperature-dependent thermal conductivity and shear viscosity of liquid water between 283 and 363 K are evaluated for eight rigid models with reverse nonequilibrium molecular dynamics (RNEMD). In comparison with experimental data, five-site models (TIP5P and TIP5P-Ew) have apparent advantages in estimating thermal conductivities than other rigid water models that overestimate the value by tens of percent. For shear viscosity, no single model can reproduce all experimental data; instead, five- and four-site models show their own strength in a certain temperature range. Meanwhile, all of the current rigid models obtain lower values than experimental data when temperature is lower than 298 K, while the TIP5P and TIP5P-Ew models can relatively accurately predict the values over others at a temperature range from 298 to 318 K. At a higher temperature range shear viscosity of liquid water can be reproduced with a four-site model (TIP4P-2005, TIP4P-Ew) fairly well.

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