scholarly journals Thermal-siphon phenomenon and thermal/electric conduction in complex networks

2019 ◽  
Vol 7 (2) ◽  
pp. 270-277 ◽  
Author(s):  
Kezhao Xiong ◽  
Zonghua Liu ◽  
Chunhua Zeng ◽  
Baowen Li
Keyword(s):  
Heat Conduction ◽  
Complex Networks ◽  
Network Structure ◽  
Energy Transport ◽  
Electrical Conductance ◽  
Electric Energy ◽  
Thermal Conductance ◽  
Coupling Scheme ◽  
Regular Lattices ◽  
Good Conductor

Abstract In past decades, a lot of studies have been carried out on complex networks and heat conduction in regular lattices. However, very little attention has been paid to the heat conduction in complex networks. In this work, we study (both thermal and electric) energy transport in physical networks rewired from 2D regular lattices. It is found that the network can be transferred from a good conductor to a poor conductor, depending on the rewired network structure and coupling scheme. Two interesting phenomena were discovered: (i) the thermal-siphon effect—namely the heat flux can go from a low-temperature node to a higher-temperature node and (ii) there exits an optimal network structure that displays small thermal conductance and large electrical conductance. These discoveries reveal that network-structured materials have great potential in applications in thermal-energy management and thermal-electric-energy conversion.

scholarly journals Modelling community structure and temporal spreading on complex networks

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Vesa Kuikka
Keyword(s):  
Community Structure ◽  
Complex Networks ◽  
Community Detection ◽  
Network Structure ◽  
Network Connectivity ◽  
Network Models ◽  
Building Blocks ◽  
Detection Algorithm ◽  
Research Area ◽  
Detection Methods

AbstractWe present methods for analysing hierarchical and overlapping community structure and spreading phenomena on complex networks. Different models can be developed for describing static connectivity or dynamical processes on a network topology. In this study, classical network connectivity and influence spreading models are used as examples for network models. Analysis of results is based on a probability matrix describing interactions between all pairs of nodes in the network. One popular research area has been detecting communities and their structure in complex networks. The community detection method of this study is based on optimising a quality function calculated from the probability matrix. The same method is proposed for detecting underlying groups of nodes that are building blocks of different sub-communities in the network structure. We present different quantitative measures for comparing and ranking solutions of the community detection algorithm. These measures describe properties of sub-communities: strength of a community, probability of formation and robustness of composition. The main contribution of this study is proposing a common methodology for analysing network structure and dynamics on complex networks. We illustrate the community detection methods with two small network topologies. In the case of network spreading models, time development of spreading in the network can be studied. Two different temporal spreading distributions demonstrate the methods with three real-world social networks of different sizes. The Poisson distribution describes a random response time and the e-mail forwarding distribution describes a process of receiving and forwarding messages.

scholarly journals Simultaneously controlling heat conduction and infrared absorption with a textured dielectric film to enhance the performance of thermopiles

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Yunqian He ◽  
Yuelin Wang ◽  
Tie Li
Keyword(s):  
Heat Conduction ◽  
Infrared Absorption ◽  
High Performance ◽  
Performance Enhancement ◽  
Dielectric Film ◽  
Great Influence ◽  
Thermal Conductance ◽  
Molding Process ◽  
Absorption Properties

AbstractThe heat conduction and infrared absorption properties of the dielectric film have a great influence on the thermopile performance. Thinning the dielectric film, reducing its contact area with the silicon substrate, or adding high-absorptivity nanomaterials has been proven to be effective in improving thermopiles. However, these methods may result in a decrease in the structural mechanical strength and increases in the fabrication complexity and cost. In this work, a new performance-enhancement strategy for thermopiles by simultaneously controlling the heat conduction and infrared absorption with a TExtured DIelectric (TEDI) film is developed and presented. The TEDI film is formed in situ by a simple hard-molding process that is compatible with the fabrication of traditional thermopiles. Compared to the control FLat DIelectric (FLDI) film, the intrinsic thermal conductance of the TEDI film can be reduced by ~18–30%, while the infrared absorption can be increased by ~7–13%. Correspondingly, the responsivity and detectivity of the fabricated TEDI film-based thermopile can be significantly enhanced by ~38–64%. An optimized TEDI film-based thermopile has achieved a responsivity of 156.89 V·W−1 and a detectivity of 2.16 × 108 cm·Hz1/2·W−1, while the response time constant can remain <12 ms. These results exhibit the great potential of using this strategy to develop high-performance thermopiles and enhance other sensors with heat transfer and/or infrared absorption mechanisms.

Impact of Nonequilibrium Between Electrons and Phonons on Heat Transfer in Metallic Nanoparticles Suspended in Dielectric Media

2005 ◽  
Vol 127 (12) ◽  
pp. 1400-1402 ◽  
Author(s):  
Y. Sungtaek Ju
Keyword(s):  
Heat Conduction ◽  
Metallic Nanoparticles ◽  
Energy Transport ◽  
Apparent Size ◽  
Dielectric Medium ◽  
Au Nanoparticle ◽  
Conduction Model ◽  
Metallic Structures ◽  
Atomic Vibrations ◽  
Dielectric Interfaces

Controlled heating of nanoparticles is a key enabling technology for various nanomanufacturing and biomedical applications. A theoretical study of energy transport in nanoparticles is conducted to elucidate the role of electron-phonon spatial nonequilibrium in heat conduction across metal-dielectric interfaces. The continuum two-temperature heat conduction model is shown to capture the apparent size dependence of the thermal interface resistance of Au nanoparticle suspensions. Consideration of coupling between electrons and atomic vibrations is important in understanding energy transport in nanoscale metallic structures suspended in a dielectric medium.

Improved influential nodes identification in complex networks

2021 ◽  
pp. 1-9
Author(s):  
Shi Dong ◽  
Wengang Zhou
Keyword(s):  
Theoretical Analysis ◽  
Complex Networks ◽  
Network Structure ◽  
Information Entropy ◽  
Network System ◽  
Weighted Degree ◽  
Identification Methods ◽  
Hybrid Mechanism ◽  
Influential Nodes ◽  
Influential Node

Influential node identification plays an important role in optimizing network structure. Many measures and identification methods are proposed for this purpose. However, the current network system is more complex, the existing methods are difficult to deal with these networks. In this paper, several basic measures are introduced and discussed and we propose an improved influential nodes identification method that adopts the hybrid mechanism of information entropy and weighted degree of edge to improve the accuracy of identification (Hm-shell). Our proposed method is evaluated by comparing with nine algorithms in nine datasets. Theoretical analysis and experimental results on real datasets show that our method outperforms other methods on performance.

Heat Conduction Through a Layered Pressure Vessel Wall

1986 ◽  
Vol 108 (4) ◽  
pp. 418-422
Author(s):  
M. Ueda ◽  
M. Kinugawa ◽  
Y. Hara ◽  
K. Yamazato
Keyword(s):  
Heat Conduction ◽  
Pressure Vessel ◽  
Vessel Wall ◽  
Thermal Contact ◽  
Thermal Conductance ◽  
Postweld Heat Treatment ◽  
Pressure Vessels ◽  
Scale Model ◽  
Thermal Contact Conductance ◽  
Simplified Method

Heat conduction tests of a layered pressure vessel wall were performed using full-scale model pressure vessel courses. Thermal conductance between layers was estimated from the test results. A simplified method, developed for the thermal analysis of layered-wall pressure vessels during postweld heat treatment and actual operation, includes thermal contact conductance at the layer interfaces which depends upon the contact pressure and gap height. Temperature changes calculated using the simplified method agreed well with the experiments.

The adaptive coupling scheme and the heterogeneity in intrinsic frequency and degree distributions of the complex networks

2014 ◽  
Vol 378 (3) ◽  
pp. 139-146 ◽  
Author(s):  
Quansheng Ren ◽  
Mingli He ◽  
Xiaoqian Yu ◽  
Qiufeng Long ◽  
Jianye Zhao
Keyword(s):  
Complex Networks ◽  
Coupling Scheme ◽  
Intrinsic Frequency ◽  
Adaptive Coupling

An Introduction to Complex Networks

2013 ◽  
Author(s):  
Jordi Bascompte ◽  
Pedro Jordano
Keyword(s):  
Complex Systems ◽  
Complex Networks ◽  
Network Structure ◽  
Ecological Networks ◽  
Broad Context ◽  
Network Approach ◽  
Mutualistic Networks ◽  
Plant Animal Interactions

Mutualisms can involve dozens, even hundreds, of species and this complexity has precluded a serious community-wide approach to plant–animal interactions. The most straightforward way to describe such an interacting community is with a network of interactions. In this approach, species are represented as nodes of two types: plants and animals. This chapter provides the tools and concepts for characterizing mutualistic networks and placing them into a broad context. This serves as a background with which to understand the structure of mutualistic networks. The discussions cover a network approach to complex systems, measures of network structure, models of network buildup, and ecological networks.

Neural network representation and optimization of thermoelectric states of multiple interacting quantum dots

2020 ◽  
Vol 22 (28) ◽  
pp. 16165-16173
Author(s):  
Hangbo Zhou ◽  
Gang Zhang ◽  
Yong-Wei Zhang
Keyword(s):  
Neural Network ◽  
Machine Learning ◽  
Quantum Dots ◽  
Seebeck Coefficient ◽  
Master Equation ◽  
Thermoelectric Properties ◽  
Electrical Conductance ◽  
Thermal Conductance ◽  
Quantum Master Equation ◽  
Network Representation

We perform quantum master equation calculations and machine learning to investigate the thermoelectric properties of multiple interacting quantum dots, including electrical conductance, Seebeck coefficient, thermal conductance and ZT.

scholarly journals Thermal conductance between water and nm-thick WS2: extremely localized probing using nanosecond energy transport state-resolved Raman

2020 ◽  
Vol 2 (12) ◽  
pp. 5821-5832
Author(s):  
Hamidreza Zobeiri ◽  
Nicholas Hunter ◽  
Ridong Wang ◽  
Xinman Liu ◽  
Hong Tan ◽  
...  
Keyword(s):  
Thermal Resistance ◽  
Energy Transport ◽  
Thermal Conductance ◽  
Interface Resistance ◽  
Effect Of Water ◽  
Interfacial Thermal Conductance

Interfacial thermal conductance between a nm-thick suspended WS2 film and water is measured using a novel nET-Raman technique. By significantly reducing the effect of water thermal resistance, the interface resistance effect become more preeminent.

A Hybrid Coupling Scheme and Stability Analysis for Coupled Solid/Fluid Turbine Blade Temperature Calculations

1998 ◽  
Author(s):  
Andreas Heselhaus
Keyword(s):  
Heat Conduction ◽  
Steady State ◽  
Turbine Blade ◽  
Gas Flow ◽  
Guide Vane ◽  
Thermal Design ◽  
Navier Stokes ◽  
Coupling Scheme ◽  
Flow Solver ◽  
Turbine Blade Cooling

Efficient thermal design of turbine blade cooling needs to take wall temperature effects on heat transfer into account. This can only be achieved by a coupled calculation of hot gas flow and blade heat conduction. In this paper principle and stability proof of an algorithm are presented that allows to couple a steady state finite element heat conduction solver with a blockstructured steady state finite volume (FV) Navier-Stokes time marching flow solver. The stability of the developed coupling procedure as well as the instability of an alternative algorithm is shown analytically and numerically. The benefits of coupled calculating are shown for a convectively cooled turbine guide vane blade. In the example treated, temperature differences of more than 100 K arise compared to the same calculation performed in an uncoupled way.

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