Dielectric properties of Shell oil transformer oil with impurities of carbon nanotubes and fullerene C60

At the temperature 293 K, the influence of two types of nanoimpurities (carbon multiwall nanotubes and C60 fullerene) both separately and together on the dielectric properties of Shell oil transformer oil has been studied. It has been shown that these impurities do not significantly effect on the value of the dielectric permittivity of Shell oil, but more significantly increase its conductivity. It has been found that in the presence of nanotubes inside Shell oil, the dependence of its electrical conductivity on the fullerene concentration is nonmonotonic. The samples with the fullerene concentration 100 ppm have the highest conductivity. At the fullerene concentration 300 ppm, the conductivity of Shell oil with the impurities of carbon nanotube and C60 fullerene becomes almost equal to the electrical conductivity of Shell oil only with the impurities of carbon nanotubes. It has been suggested that C60 fullerene can be used to reduce the electrical conductivity of Shell oil with magnetic nanoparticles required to increase the cooling efficiency of transformers under the action of their own magnetic field.

A Review of Inkjet Printed Graphene and Carbon Nanotubes Based Gas Sensors

Graphene and carbon nanotube (CNT)-based gas/vapor sensors have gained much traction for numerous applications over the last decade due to their excellent sensing performance at ambient conditions. Inkjet printing various forms of graphene (reduced graphene oxide or modified graphene) and CNT (single-wall nanotubes (SWNTs) or multiwall nanotubes (MWNTs)) nanomaterials allows fabrication onto flexible substrates which enable gas sensing applications in flexible electronics. This review focuses on their recent developments and provides an overview of the state-of-the-art in inkjet printing of graphene and CNT based sensors targeting gases, such as NO2, Cl2, CO2, NH3, and organic vapors. Moreover, this review presents the current enhancements and challenges of printing CNT and graphene-based gas/vapor sensors, the role of defects, and advanced printing techniques using these nanomaterials, while highlighting challenges in reliability and reproducibility. The future potential and outlook of this rapidly growing research are analyzed as well.

Comparative Research Concerning Hydrogen Storage by Platinum, Ruthenium and Iridium Doped Multiwall Carbon Nanotubes

A comparative research related to hydrogen adsorption capacity of multiwall nanotubes (MWNTs) doped with Platinum (Pt), Ruthenium (Ru) and Iridium (Ir) was carried out. Carbonic materials are considered to be one of the most promising materials for hydrogen adsorption and storage;they have different applications and fuel cells technology may be considered the most important of them. By using transitional metals for doping carbonic materials, the adsorption capacity increases, can approach the target of 6.5% weight ratio of H2 adsorbed in a substrate. The doping procedure consists in a physical or chemical method which involves metal for doping of a nano carbon structure. The use of ultrasounds is known in order to activate the substrate by inducing fractures within its internal structure. The adsorption capacity of the carbonic materials, which is a consequence of spill over phenomena, has been determined both by physical adsorption and by cyclic voltammetry. The substrates have been characterized in order to determine their BET and microspores surface and structure. The collected data related to the adsorption capacity have been processed by using a dedicated software. The results have been compared with the available data from literature and a good consistency was found.

Adhesion of Partially and Fully Collapsed Nanotubes

The competition between the structural rigidity and the van der Waals interactions may lead to collapsing of aligned nanotubes, and the resulting changes of both configurations and properties promise the applications of nanotubes in nano-composites and nano-electronics. In this paper, a finite-deformation model is applied to study the adhesion of parallel multiwall nanotubes with both partial and full collapsing, in which the noncontact adhesion energy is analytically determined. The analytical solutions of both configurations and energies of collapsed nanotubes are consistent with the molecular dynamics (MD) results, demonstrating the effectiveness of the finite-deformation model. To study the critical conditions of generating the partially and fully collapsed multiwall nanotubes, our analytical model gives the predictions for both the geometry- and energy-related critical diameters, which are helpful for the stability analysis and design of nanotube-based nano-devices.

Investigation of the Relaxation Mechanical Properties of Nanocomposites Based on High-Density Polyethylene

The effect of nanotubes and nanofibres on the stress relaxation of nanocomposites based on high-density polyethylene (HDPE) was studied. It was found that a very low concentration of multiwall nanotubes (0.1 wt%) leads to a significant increase in the relaxing stresses over the entire period of relaxation. Generalised curves of the relaxation process were plotted, and it was found that the greatest reinforcing effect is rendered by the multiwall nanotubes with the greatest specific surface.

Modelling of adsorption and intercalation of hydrogen on/into tungsten disulphide multilayers and multiwall nanotubes

First-principles calculations, supported by new experimental evidences, have been used to clarify the different processes and mechanisms related to the interaction of hydrogen with WS2 nanomaterials.

In vitro evaluation of the antibacterial activity of modified multi-walled carbon nanotubes with phenolic extracts

Conventional Antibiotics such as ciprofloxacin, ofloxacin and levofloxacin are an important group of antimicrobials which are widely used in the treatment of various infectious diseases. Long-term treatment with antibiotics can cause side effects in consumers. Bactericidal antibiotics may persuade the establishment of toxic reactive oxygen types (ROS) in bacteria. In the present study, we tried to eliminate the side effects of antibiotics by modification of multi wall carboxylated nanotubes with phenolic extractives that are extracted of pigmented vegetables. Very low concentrations of functionalized nanotubes were tested against both Gram-positive and Gram-negative bacteria. Antibacterial activity of the products was compared with MIC values of conventional antibiotics. In vitro studies represented that killed bacteria in the presence of low concentrations of modified nanotubes. so, the extremely abilities of functionalized carboxylated multiwall nanotubes have the potential to be described as innocuous antibiotic candidates.