scholarly journals Graphene-Based Composite Membrane Prepared from Solid Carbon Source Catalyzed by Ni Nanoparticles

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3392
Author(s):  
Jing Li ◽  
Jialiang Liu ◽  
Jinshui Liu ◽  
Jinfeng Lai ◽  
Yuxun Chen ◽  
...  
Keyword(s):  
High Temperature ◽  
Thermal Management ◽  
Composite Membrane ◽  
Hot Spots ◽  
Heat Dissipation ◽  
Methyl Cellulose ◽  
Phonon Transport ◽  
Multilayer Graphene ◽  
Ni Nanoparticles ◽  
Hydroxypropyl Methyl Cellulose

Emerging as a light, flexible and highly thermally conductive material, graphene-based membranes have attracted extensive attention in thermal management field. However, the preparation of high-quality graphene-based membranes usually involves complex processes and thermal annealing at ultra-high temperature, which limits their large-scale application in thermal management field. In our study, reduced graphene oxide-Ni-hydroxypropyl methyl cellulose (RGO-Ni-HPMC) composite membrane was prepared from catalytic pyrolysis of hydroxypropyl methyl cellulose (HPMC) with Ni nanoparticles to generate multilayer graphene and form phonon transport channels between adjacent graphene layers. Further, our study shows that the RGO-Ni-HPMC composite membrane has a good heat dissipation effect at the hot spots at high temperature. The average temperature of hot spots is reduced by 11.5 °C. It is expected to solve the heat dissipation problem of high-power electronic equipment.

High temperature thermal management with boron nitride nanosheets

Nanoscale ◽  
2018 ◽  
Vol 10 (1) ◽  
pp. 167-173 ◽  
Author(s):  
Yilin Wang ◽  
Lisha Xu ◽  
Zhi Yang ◽  
Hua Xie ◽  
Puqing Jiang ◽  
...  
Keyword(s):  
High Temperature ◽  
Boron Nitride ◽  
Thermal Management ◽  
Power Density ◽  
High Power ◽  
Heat Dissipation ◽  
Rapid Development ◽  
High Power Density ◽  
Boron Nitride Nanosheets

The rapid development of high power density devices requires more efficient heat dissipation.

scholarly journals Manipulation of the Glass Transition Properties of a High-Solid System Made of Acrylic Acid-N,N′-Methylenebisacrylamide Copolymer Grafted on Hydroxypropyl Methyl Cellulose

2021 ◽  
Vol 22 (5) ◽  
pp. 2682
Author(s):  
Nazim Nassar ◽  
Felicity Whitehead ◽  
Taghrid Istivan ◽  
Robert Shanks ◽  
Stefan Kasapis
Keyword(s):  
Glass Transition ◽  
Acrylic Acid ◽  
Methyl Cellulose ◽  
Small Deformation ◽  
Polymerization Reaction ◽  
Solid Matrix ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
High Solid ◽  
Hydroxypropyl Methyl Cellulose

Crosslinking of hydroxypropyl methyl cellulose (HPMC) and acrylic acid (AAc) was carried out at various compositions to develop a high-solid matrix with variable glass transition properties. The matrix was synthesized by the copolymerisation of two monomers, AAc and N,N′-methylenebisacrylamide (MBA) and their grafting onto HMPC. Potassium persulfate (K2S2O8) was used to initiate the free radical polymerization reaction and tetramethylethylenediamine (TEMED) to accelerate radical polymerisation. Structural properties of the network were investigated with Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), modulated differential scanning calorimetry (MDSC), small-deformation dynamic oscillation in-shear, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The results show the formation of a cohesive macromolecular entity that is highly amorphous. There is a considerable manipulation of the rheological and calorimetric glass transition temperatures as a function of the amount of added acrylic acid, which is followed upon heating by an extensive rubbery plateau. Complementary TGA work demonstrates that the initial composition of all the HPMC-AAc networks is maintained up to 200 °C, an outcome that bodes well for applications of targeted bioactive compound delivery.

scholarly journals A Thermal Transport Study of Branched Carbon Nanotubes with Cross and T-Junctions

2021 ◽  
Vol 11 (13) ◽  
pp. 5933
Author(s):  
Wei-Jen Chen ◽  
I-Ling Chang
Keyword(s):  
Heat Transfer ◽  
Carbon Nanotubes ◽  
Thermal Management ◽  
Thermal Transport ◽  
Topological Defects ◽  
Branch Length ◽  
Phonon Transport ◽  
Heat Current ◽  
Transport Mechanisms ◽  
Non Equilibrium Molecular Dynamics

This study investigated the thermal transport behaviors of branched carbon nanotubes (CNTs) with cross and T-junctions through non-equilibrium molecular dynamics (NEMD) simulations. A hot region was created at the end of one branch, whereas cold regions were created at the ends of all other branches. The effects on thermal flow due to branch length, topological defects at junctions, and temperature were studied. The NEMD simulations at room temperature indicated that heat transfer tended to move sideways rather than straight in branched CNTs with cross-junctions, despite all branches being identical in chirality and length. However, straight heat transfer was preferred in branched CNTs with T-junctions, irrespective of the atomic configuration of the junction. As branches became longer, the heat current inside approached the values obtained through conventional prediction based on diffusive thermal transport. Moreover, directional thermal transport behaviors became prominent at a low temperature (50 K), which implied that ballistic phonon transport contributed greatly to directional thermal transport. Finally, the collective atomic velocity cross-correlation spectra between branches were used to analyze phonon transport mechanisms for different junctions. Our findings deeply elucidate the thermal transport mechanisms of branched CNTs, which aid in thermal management applications.

scholarly journals Heat transport through propagon-phonon interaction in epitaxial amorphous-crystalline multilayers

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Takafumi Ishibe ◽  
Ryo Okuhata ◽  
Tatsuya Kaneko ◽  
Masato Yoshiya ◽  
Seisuke Nakashima ◽  
...  
Keyword(s):  
Group Velocity ◽  
Density Of States ◽  
Heat Dissipation ◽  
Lattice Mismatch ◽  
Lead Telluride ◽  
Amorphous Layer ◽  
Interface Layer ◽  
Phonon Transport ◽  
Nanoscale Systems ◽  
Phonon Group Velocity

AbstractManaging heat dissipation is a necessity for nanoscale electronic devices with high-density interfaces, but despite considerable effort, it has been difficult to establish the phonon transport physics at the interface due to a “complex” interface layer. In contrast, the amorphous/epitaxial interface is expected to have almost no “complex” interface layer due to the lack of lattice mismatch strain and less associated defects. Here, we experimentally observe the extremely-small interface thermal resistance per unit area at the interface of the amorphous-germanium sulfide/epitaxial-lead telluride superlattice (~0.8 ± 4.0 × 10‒9 m2KW−1). Ab initio lattice dynamics calculations demonstrate that high phonon transmission through this interface can be predicted, like electron transport physics, from large vibron-phonon density-of-states overlapping and phonon group velocity similarity between propagon in amorphous layer and “conventional” phonon in crystal. This indicates that controlling phonon (or vibron) density-of-states and phonon group velocity similarity can be a comprehensive guideline to manage heat conduction in nanoscale systems.

scholarly journals Bi-Functional Composting the Sulfonic Acid Based Proton Exchange Membrane for High Temperature Fuel Cell Application

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1000
Author(s):  
Guoxiao Xu ◽  
Juan Zou ◽  
Zhu Guo ◽  
Jing Li ◽  
Liying Ma ◽  
...  
Keyword(s):  
High Temperature ◽  
Fuel Cell ◽  
Composite Membrane ◽  
Sulfonic Acid ◽  
Elevated Temperatures ◽  
Mechanical Stability ◽  
Strong Dependence ◽  
Proton Exchange ◽  
Nafion Membrane ◽  
Silica Nanofiber

Although sulfonic acid (SA)-based proton-exchange membranes (PEMs) dominate fuel cell applications at low temperature, while sulfonation on polymers would strongly decay the mechanical stability limit the applicable at elevated temperatures due to the strong dependence of proton conduction of SA on water. For the purpose of bifunctionally improving mechanical property and high-temperature performance, Nafion membrane, which is a commercial SA-based PEM, is composited with fabricated silica nanofibers with a three-dimensional network structure via electrospinning by considering the excellent water retention capacity of silica. The proton conductivity of the silica nanofiber–Nafion composite membrane at 110 °C is therefore almost doubled compared with that of a pristine Nafion membrane, while the mechanical stability of the composite Nafion membrane is enhanced by 44%. As a result, the fuel cell performance of the silica nanofiber-Nafion composite membrane measured at high temperature and low humidity is improved by 38%.

scholarly journals Thermal Analysis of Cold Plate with Different Configurations for Thermal Management of a Lithium-Ion Battery

Batteries ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 17
Author(s):  
Seyed Saeed Madani ◽  
Erik Schaltz ◽  
Søren Knudsen Kær
Keyword(s):  
Thermal Analysis ◽  
Temperature Distribution ◽  
Lithium Ion Battery ◽  
Thermal Management ◽  
Electric Vehicles ◽  
Heat Dissipation ◽  
Lithium Ion ◽  
Cold Plate ◽  
Liquid Cooling ◽  
Cooling Design

Thermal analysis and thermal management of lithium-ion batteries for utilization in electric vehicles is vital. In order to investigate the thermal behavior of a lithium-ion battery, a liquid cooling design is demonstrated in this research. The influence of cooling direction and conduit distribution on the thermal performance of the lithium-ion battery is analyzed. The outcomes exhibit that the appropriate flow rate for heat dissipation is dependent on different configurations for cold plate. The acceptable heat dissipation condition could be acquired by adding more cooling conduits. Moreover, it was distinguished that satisfactory cooling direction could efficiently enhance the homogeneity of temperature distribution of the lithium-ion battery.

Evaluation of Hydroxypropyl Cellulose and Hydroxypropyl Methyl Cellulose as Aqueous Based Film Coatings

1981 ◽  
Vol 7 (6) ◽  
pp. 693-716 ◽  
Author(s):  
Gilbert Banker ◽  
Garnet Peck ◽  
Steve Ja ◽  
Pichai Pirakitikulr ◽  
Deeni Taylor
Keyword(s):  
Methyl Cellulose ◽  
Hydroxypropyl Cellulose ◽  
Hydroxypropyl Methyl Cellulose ◽  
Film Coatings

Scanning Thermal Microscopy of Carbon Nanotubes

2000 ◽  
Author(s):  
Li Shi ◽  
Sergei Plyasunov ◽  
Adrian Bachtold ◽  
Paul L. McEuen ◽  
Arunava Majumdar
Keyword(s):  
Carbon Nanotubes ◽  
Thermal Imaging ◽  
Heat Dissipation ◽  
Energy Transport ◽  
Imaging Technique ◽  
Mechanical Deformation ◽  
Phonon Transport ◽  
Scanning Thermal Microscopy ◽  
Thermal Microscopy ◽  
Nanoelectronic Circuits

Abstract This paper reports the use of scanning thermal microscopy (SThM) for studying heat dissipation and phonon transport in nanoelectronic circuits consisting of carbon nanotubes (CNs). Thermally designed and batch fabricated SThM probes were used to resolve the phonon temperature distribution in the CN circuits with a spatial resolution of 50 nm. Heat dissipation at poor metal-CN contacts could be readily found by the thermal imaging technique. Important questions regarding energy transport in nanoelectronic circuits, such as where is heat dissipated, whether the electrons and phonons are in equilibrium, how phonons are transported, and what are the effects of mechanical deformation on the transport and dissipation properties, are addressed in this work.

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