Effect Of Multi-walled Carbon Research Articles

Effect of multi-wall carbon nanotubes/strontium ferrite nanoparticles on the microstructure, phase, magnetic and electromagnetic behavior of carbon aerogel composites

This research examined the electromagnetic behavior of a carbon aerogel composite containing multi-wall carbon nanotubes and strontium ferrite nanoparticles within the X band range (8.12–2.4 GHz). For this purpose, 10 wt% of carbon nanotubes and 5 wt%, 10 wt%, and 15 wt% of strontium ferrite nanoparticles were applied in the pyrolyzed cellulose aerogel composite. For structural and magnetic characterization of the samples, different techniques such as X-ray diffraction test, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, vector network analyzer, and vibrational magnetometer (VSM) were used. The VSM results indicated that the presence of 10 wt% strontium ferrite nanoparticles in the carbon aerogel substrate caused saturation magnetization of 2.31 emu/g. However, upon adding 10 wt% carbon nanotubes, the saturation magnetization value reached 6.82 emu/g. Based on the results, the greatest shielding efficiency (within the X-band = 110 ± 0.8 dB) occurred in the sample containing 10 wt% carbon nanotube alongside 5 wt% strontium ferrite at thicknesses of 4 mm. Furthermore, the reflection loss value of this sample was −48.59 ± 0.5 dB at a thickness of 3 cm and a frequency of 10.92 GHz.

The effect of multi-wall carbon nanotubes/turbine meter oil nanofluid concentration on the thermophysical properties of lubricants

This study aims to evaluate the effect of the concentration of multi-wall carbon nanotubes (MWCNTs)/ turbine meter oil nanofluids on thermophysical attributes of lubricants, including the viscosity index, kinematics viscosity, flash point, pressure drop, and friction factor. The results indicated that the viscosity of pure lubricant was enhanced with the addition of MWCNTs and increased with decreasing temperature. The viscosity index at a concentration of 0.3 wt% was increased by 2.43%. The flash point temperature at concentrations of 0.3 wt% and 0.4 wt% was increased by 4.4%. Experiments were conducted to obtain the pressure drop data and friction factor. The friction factor increased for all concentrations of MWCNTs in pure oil; the highest increment in the friction factor, with the addition of 0.3 wt% nanoparticles to pure oil in 0.069 m/s inlet velocity, was 10.41%. The mean deviation between the experimental friction factor and simulation friction factor was 0.029.

The effect of multi-walled carbon nanotubes/hydroxyapatite nanocomposites on biocompatibility

In the present study, multi-walled carbon nanotubes/hydroxyapatite (MWCNTs/HA) nanocomposites with various MWCNT contents were manufactured by sol-gel processing. The MWCNTs/HA powder was characterized using field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Raman analysis. The results show that the MWCNTs were fully covered with HA nanoparticles and help forming the crystallized hydroxyapatite. In addition, in vitro tests highlighted the excellent biocompatibility of the MWCNTs/HA composite.

The Effect of Multi-Walled Carbon Nanotube/Water Nanofluid on Thermal Performance of a Two-Phase Closed Thermosyphon

In this study, the thermal performance of a two-phase closed thermosyphon operating with multi-walled carbon nanotube/deionized water nanofluids is studied. The experiments were conducted in a copper two-phase closed thermosyphon with a length of 450 mm and diameter of 20 mm. A multi-walled carbon nanotube is used with a diameter of 10–20 nm and length of 5–15 microns. The results of experimental tests indicated that with the increasing weight concentration of nanofluids, thermal efficiency improves and Nusselt number and thermal resistance of thermosyphon decrease. In addition, the increment in input power leads to an increase in thermal efficiency and Nusselt number while it reduces thermal resistance.