scholarly journals Effect of Liquid Phase Additions on Microstructure and Thermal Properties in Copper and Copper-Diamond Composites

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
A. Rape ◽  
X. Liu ◽  
A. Kulkarni ◽  
J. Singh
Keyword(s):  
Thermal Conductivity ◽  
Liquid Phase ◽  
Thermal Management ◽  
Diamond Particle ◽  
Two Phase ◽  
New Approach ◽  
The Matrix ◽  
Reactive Liquid ◽  
Field Assisted Sintering ◽  
Solid Liquid

This study details a new approach to creating copper-diamond composite materials for thermal management applications by using a two-phase (solid-liquid) approach in powder metallurgy using Field Assisted Sintering Technology (FAST). Silver-copper alloyed powder at eutectic compositions was used as a nonreactive liquid phase while Cu5Si was used as a reactive liquid phase. Microstructure results are reported favorably comparing the additions of a small amount of liquid phase to pure solid state sintering. Additionally, EDX results indicate that the liquid phase material fills gaps at the interface of the matrix and diamond particle resulting in improved microstructure and density. Thermal conductivity results show that liquid phase additions improve the thermal conductivity of composites compared to composites without any liquid phase, but Si additions cause a severe drop in baseline conductivity.

Hydrocyclone Two Phase Flow Experimental Research Based on Fluid Mechanics

2012 ◽  
Vol 625 ◽  
pp. 117-120
Author(s):  
Hui Xu ◽  
Xiao Hong Chen
Keyword(s):  
Numerical Simulation ◽  
Liquid Phase ◽  
Fluid Mechanics ◽  
Production Capacity ◽  
Phase Flow ◽  
Input Flow ◽  
Two Phase ◽  
Output Flow ◽  
Input Pressure ◽  
Solid Liquid

The liquid phase experiment is finished ,and the relation curve of input- pressure and input-flow、output-flow、distributary rate are worked out.We are bout to calculate the production capacity and define the best distribution rate of the operation parameters.At the same time , the solid-liquid phase separating experiment are made too and we conclude the relation curve of input-pressure and consistency 、separating efficiency .Comparing with the numerical simulation ,the result is reasonable.

Stretching-Induced Thermal Conductivity Change in Shape-Memory Polymer Composites

2020 ◽  
Author(s):  
Stephen Hostler ◽  
Mohnish Peswani ◽  
Han Yang ◽  
Harrison Paul ◽  
Stuart J. Rowan ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Shape Memory ◽  
Thermal Management ◽  
Energy Savings ◽  
Thermal State ◽  
Shape Memory Polymer ◽  
Applied Strain ◽  
Proof Of Concept ◽  
Conductivity Change ◽  
The Matrix

Abstract Active thermal materials like thermal diodes, regulators, and switches have the potential to revolutionize thermal management, creating an opportunity for significant energy savings. We present results on a thermal switching composite that changes its thermal conductivity based on applied strain. The composite is constructed of highly-crystalline, high aspect ratio cellulose nanocrystal (CNC) nanorods embedded in a shape-memory polymer matrix. The properties of the matrix allow for changes to the thermal state to be indefinitely retained and also for the state to be reversed. A switching ratio of two is achieved for this proof-of-concept composite. By comparing the measured results to a Maxwell mixing model, the primary drivers of the thermal conductivity change are traced to changes in crystallinity of the matrix and CNC alignment.

scholarly journals Thermal Conductivity and Cure Kinetics of Epoxy-Boron Nitride Composites—A Review

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3634
Author(s):  
John M. Hutchinson ◽  
Sasan Moradi
Keyword(s):  
Thermal Conductivity ◽  
Boron Nitride ◽  
Thermal Management ◽  
Filler Content ◽  
Electronic Devices ◽  
Cure Kinetics ◽  
The Matrix ◽  
Thermally Conductive ◽  
Filler Particles ◽  
Kinetics Of

Epoxy resin composites filled with thermally conductive but electrically insulating particles play an important role in the thermal management of modern electronic devices. Although many types of particles are used for this purpose, including oxides, carbides and nitrides, one of the most widely used fillers is boron nitride (BN). In this review we concentrate specifically on epoxy-BN composites for high thermal conductivity applications. First, the cure kinetics of epoxy composites in general, and of epoxy-BN composites in particular, are discussed separately in terms of the effects of the filler particles on cure parameters and the cured composite. Then, several fundamental aspects of epoxy-BN composites are discussed in terms of their effect on thermal conductivity. These aspects include the following: the filler content; the type of epoxy system used for the matrix; the morphology of the filler particles (platelets, agglomerates) and their size and concentration; the use of surface treatments of the filler particles or of coupling agents; and the composite preparation procedures, for example whether or not solvents are used for dispersion of the filler in the matrix. The dependence of thermal conductivity on filler content, obtained from over one hundred reports in the literature, is examined in detail, and an attempt is made to categorise the effects of the variables and to compare the results obtained by different procedures.

scholarly journals Ultra-Robust Thermoconductive Films Made from Aramid Nanofiber and Boron Nitride Nanosheet for Thermal Management Application

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2028
Author(s):  
Li-Hua Zhao ◽  
Yun Liao ◽  
Li-Chuan Jia ◽  
Zhong Wang ◽  
Xiao-Long Huang ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Boron Nitride ◽  
Thermal Management ◽  
Electrical Insulation ◽  
Interfacial Thermal Resistance ◽  
Conductive Composites ◽  
Boron Nitride Nanosheet ◽  
Brick And Mortar ◽  
The Matrix ◽  
Liquid Phase Exfoliation

The development of highly thermally conductive composites with excellent electrical insulation has attracted extensive attention, which is of great significance to solve the increasingly severe heat concentration issue of electronic equipment. Herein, we report a new strategy to prepare boron nitride nanosheets (BNNSs) via an ion-assisted liquid-phase exfoliation method. Then, silver nanoparticle (AgNP) modified BNNS (BNNS@Ag) was obtained by in situ reduction properties. The exfoliation yield of BNNS was approximately 50% via the ion-assisted liquid-phase exfoliation method. Subsequently, aramid nanofiber (ANF)/BNNS@Ag composites were prepared by vacuum filtration. Owing to the “brick-and-mortar” structure formed inside the composite and the adhesion of AgNP, the interfacial thermal resistance was effectively reduced. Therefore, the in-plane thermal conductivity of ANF/BNNS@Ag composites was as high as 11.51 W m−1 K−1, which was 233.27% higher than that of pure ANF (3.45 W m−1 K−1). The addition of BNNS@Ag maintained tensile properties (tensile strength of 129.14 MPa). Moreover, the ANF/BNNS@Ag films also had good dielectric properties and the dielectric constant was below 2.5 (103 Hz). Hence, the ANF/BNNS@Ag composite shows excellent thermal management performance, and the electrical insulation and mechanical properties of the matrix are retained, indicating its potential application prospects in high pressure and high temperature application environments.

scholarly journals Synthesis of Methyl 4,6-Di-O-ethyl-α-d-glucopyranoside-Based Azacrown Ethers and Their Effects in Asymmetric Reactions

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4668
Author(s):  
István Orbán ◽  
Bertalan Varga ◽  
Péter Bagi ◽  
László Hegedűs ◽  
Péter Bakó ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Liquid Phase ◽  
Crown Ethers ◽  
Asymmetric Induction ◽  
Crown Compounds ◽  
Two Phase ◽  
Azacrown Ethers ◽  
Negative Effect ◽  
Darzens Condensation ◽  
Solid Liquid

Carbohydrate-based crown ethers have been reported to be able to generate asymmetric induction in certain reactions. Previously, it was proved that the monosaccharide unit, the anomeric substituent, and the sidearm could influence the catalytic activity of the monoaza-15-crown-5 macrocycles derived from sugars. In order to gain information about the effect of the flexibility, 4,6-di-O-ethyl-glucoside-based crown compounds were synthesized, and their efficiency was compared to the 4,6-O-benzylidene analogues. It was found that the absence of the two-ring annulation has a negative effect on the enantioselectivity in liquid-liquid two-phase reactions: in the Darzens condensation of 2-chloroacetophenone and in the epoxidation of chalcone. The same trend was observed in the solid-liquid phase Michael addition of diethyl acetamidomalonate. Surprisingly, in the solid-liquid phase cyclopropanation of benzylidenemalononitrile, one of the new catalysts was highly enantioselective (99% ee).

scholarly journals Acid and enyzymatic hyrolysis of Solarium tuberosum L. Glycoalkaloids: Comparison results

2006 ◽  
Vol 12 (4) ◽  
pp. 241-245 ◽  
Author(s):  
Nada Nikolic ◽  
Mihajlo Stankovic ◽  
Milorad Cakic
Keyword(s):  
Liquid Phase ◽  
Enzymatic Hydrolysis ◽  
Acid Hydrolysis ◽  
Liquid System ◽  
Two Phase ◽  
Comparison Results ◽  
Phase Liquid ◽  
Comparison Of The Results ◽  
Solid Liquid ◽  
Hydrolysis Of

A comparison of the results of the acid and enzymatic hydrolysis of GA from potato haulm and tuber sprouts is presented in this paper. Different systems were used for acid hydrolysis: monophase liquid, two-phase liquid-liquid or solid-liquid and three-phase solid-liquid-liquid systems. Enzymatic hydrolysis was carried out by enzymes present in fresh haulm and fresh tuber sprouts and the fresh juice obtained from fresh plant material. The procedure of acid hydrolysis of GA from potato sprouts in a two-phase liquid-liquid system was selected as the optimal procedure for obtaining solanidine. The liquid-liquid system was composed of GA extract with hydrochloric acid as the first liquid phase and chloroform as the second liquid phase. A degree of GA hydrolysis of 96% and a solanidine yield of 1.50 g per 100 g of dried tuber sprouts after 90 minutes were then achieved.

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