scholarly journals Measurement and study of thermophysical properties of nanofluids with carbon nanotubes

2021 ◽  
Vol 2119 (1) ◽  
pp. 012117
Author(s):  
V Ya Rudyak ◽  
G R Dashapilov ◽  
A A Shupik
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Thermophysical Properties ◽  
Weight Concentration ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Single Walled Cnts ◽  
Walled Cnts

Abstract This article is devoted to the study of the thermophysical properties of nanofluids with single-walled and multi-walled carbon nanotubes (CNT). Their weight concentration varied from 0.05 to 0.2%. Nanofluids, based on ethylene glycol and water, were studied. Dispersants were also used. The diffusion of CNT had been systematically investigated by the method of dynamic light scattering and their effective hydrodynamic dimensions were determined. The rheology and viscosity of all nanofluids were studied. It is shown that nanofluids are either pseu-doplastic or viscoplastic. Their rheology changes with increasing CNT concentration and temperature. However, in all cases, the viscosity of nanofluids with single-walled CNTs is signifi-cantly higher than that of nanofluids with multi-walled CNTs. In the last part, the electrical conductivity of all these nanofluids and the dispersants effect on it are investigated.

Depolarized dynamic light scattering study of multi-walled carbon nanotubes in solution

2013 ◽  
Vol 3 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Takeshi Eitoku ◽  
Masayoshi Tange ◽  
Haruhisa Kato ◽  
Toshiya Okazaki
Keyword(s):  
Carbon Nanotubes ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Multi Walled Carbon Nanotubes ◽  
Scattering Study ◽  
Walled Carbon Nanotubes

scholarly journals Enhancement of Electrical Conductivity of Aluminum-Based Nanocomposite Produced by Spark Plasma Sintering

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1150
Author(s):  
Nicolás A. Ulloa-Castillo ◽  
Roberto Hernández-Maya ◽  
Jorge Islas-Urbano ◽  
Oscar Martínez-Romero ◽  
Emmanuel Segura-Cárdenas ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Spark Plasma Sintering ◽  
Experimental Tests ◽  
Powder Morphology ◽  
Plasma Sintering ◽  
Multi Walled Carbon Nanotubes ◽  
Spark Plasma ◽  
Ball Milling Technique ◽  
Walled Carbon Nanotubes

This article focuses on exploring how the electrical conductivity and densification properties of metallic samples made from aluminum (Al) powders reinforced with 0.5 wt % concentration of multi-walled carbon nanotubes (MWCNTs) and consolidated through spark plasma sintering (SPS) process are affected by the carbon nanotubes dispersion and the Al particles morphology. Experimental characterization tests performed by scanning electron microscopy (SEM) and by energy dispersive spectroscopy (EDS) show that the MWCNTs were uniformly ball-milled and dispersed in the Al surface particles, and undesirable phases were not observed in X-ray diffraction measurements. Furthermore, high densification parts and an improvement of about 40% in the electrical conductivity values were confirmed via experimental tests performed on the produced sintered samples. These results elucidate that modifying the powder morphology using the ball-milling technique to bond carbon nanotubes into the Al surface particles aids the ability to obtain highly dense parts with increasing electrical conductivity properties.

scholarly journals Synthesis, Characterization and Study of DC Electrical Conductivity of Poly[MWCNT/Imidoselenium] Composite

2019 ◽  
Author(s):  
Abeer O. Obeid ◽  
Fatma Al-Yusufy ◽  
Sama A Al-Aghbari ◽  
omar alshujaa ◽  
Yassin Gaber ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Selenium Dioxide ◽  
Chemical Functionalization ◽  
Dc Electrical Conductivity ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

<p>The chemical functionalization of amino multi-walled carbon nanotubes (MWCNT-NH<sub>2</sub>) by selenium dioxide (SeO<sub>2</sub>) was used to produce Poly [MWCNT/Imidoselenium] composite. The prepared poly-composite was characterized by FTIR, SEM, TEM, XRD, UV, DSC and TGA. The DC electrical conductivity of poly-composite was 4.3×10<sup>-4</sup> S/cm due to the interaction between the nanotubes. </p>

The effect of functionalization on structure and electrical conductivity of multi-walled carbon nanotubes

2008 ◽  
Vol 10 (S1) ◽  
pp. 77-88 ◽  
Author(s):  
Cher Hon Lau ◽  
Raoul Cervini ◽  
Stephen R. Clarke ◽  
Milena Ginic Markovic ◽  
Janis G. Matisons ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

STM/STS investigation of carbon nanotubes deposited on Bi2Te3 surface

Open Physics ◽  
2009 ◽  
Vol 7 (2) ◽  
Author(s):  
Maciej Bazarnik ◽  
Maciej Cegiel ◽  
Piotr Biskupski ◽  
Monika Jazdzewska ◽  
SÅ‚awomir Mielcarek ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electronic Structure ◽  
Scanning Tunneling Microscopy ◽  
Structural Defects ◽  
Scanning Tunneling ◽  
Narrow Gap ◽  
Tunneling Microscopy ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Walled Cnts

AbstractThis paper reports our scanning tunneling microscopy and spectroscopy (STM/STS) study of double-walled and multi-walled carbon nanotubes (CNTs) of different diameter deposited on Bi2Te3 (narrow gap semiconductor). The approximate diameter of the studied double-walled and multi-walled CNTs was 2 nm and 8 nm, respectively. Crystalline Bi2Te3 was used as a substrate to enhance the contrast between the CNTs and the substrate in the STS measurements performed to examine peculiarities of CNT morphology, such as junctions, ends or structural defects, in terms of their electronic structure.

A Comparison of the Effect of Hydroxyl Modified Carbon Nanotubes and Graphenes on the Electrical and Mechanical Properties of Their Polyurethane Composites

2012 ◽  
Vol 622-623 ◽  
pp. 781-786
Author(s):  
Sarojini Swain ◽  
Subhendu Bhattacharya ◽  
Ram Avatar Sharma ◽  
Lokesh Chaudhari
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Filler Content ◽  
Graphene Nanosheets ◽  
Three Dimensional ◽  
Conduction System ◽  
Multi Walled Carbon Nanotubes ◽  
Electrical Conduction Mechanisms ◽  
Modified Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Hydroxyl modified multi-walled carbon nanotubes (OH-MWCNT)/ polyurethane (PU) and graphene nanosheets (GNS)/PU composites were prepared by dispersing the OH-MWCNT and GNS at different wt % in to the PU matrix. It was found that the electrical percolation threshold of the GNS/PU composite is much higher compared to that of OH-MWCNT/PU and also the electrical conductivity of the OH-MWCNT/PU composite is higher than the GNS/PU composite in the same level of filler content. This may be due to the two composites having different electrical conduction mechanisms: The OH-MWCNT/PU composite represents a three dimensional conduction system while, the GNS/PU composite represents a two dimensional conduction system. The improvement in the electrical conductivity with the incorporation of GNS as a filler in the composite is far lower than what theoretically expected. It is also observed that the tensile strength of the OH-MWCNT/PU composite is higher compared to the GNS/PU in the same level filler content.

scholarly journals Effect of Multi-Walled Carbon Nanotubes-Based Nanofluids on Marine Gas Turbine Intercooler Performance

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2300
Author(s):  
Salah Almurtaji ◽  
Naser Ali ◽  
Joao A. Teixeira ◽  
Abdulmajid Addali
Keyword(s):  
Carbon Nanotubes ◽  
Gas Turbine ◽  
Thermophysical Properties ◽  
Outlet Temperature ◽  
Gas Temperature ◽  
Pumping Power ◽  
Turbine Engine ◽  
Compressed Gas ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Coolants play a major role in the performance of heat exchanging systems. In a marine gas turbine engine, an intercooler is used to reduce the compressed gas temperature between the compressor stages. The thermophysical properties of the coolant running within the intercooler directly influence the level of enhancement in the performance of the unit. Therefore, employing working fluids of exceptional thermal properties is beneficial for improving performance in such applications, compared to conventional fluids. This paper investigates the effect of utilizing nanofluids for enhancing the performance of a marine gas turbine intercooler. Multi-walled carbon nanotubes (MWCNTs)-water with nanofluids at 0.01–0.10 vol % concentration were produced using a two-step controlled-temperature approach ranging from 10 °C to 50 °C. Next, the thermophysical properties of the as-prepared suspensions, such as density, thermal conductivity, specific heat capacity, and viscosity, were characterized. The intercooler performance was then determined by employing the measured data of the MWCNTs-based nanofluids thermophysical properties in theoretical formulae. This includes determining the intercooler effectiveness, heat transfer rate, gas outlet temperature, coolant outlet temperature, and pumping power. Finally, a comparison between a copper-based nanofluid from the literature with the as-prepared MWCNTs-based nanofluid was performed to determine the influence of each of these suspensions on the intercooler performance.

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