Carriers of the protective effectiveness of used motor oils

The fractional composition of M-10G₂(k) used motor oil was determined. The effect of its component son the protective effectiveness was investigated. Resins and asphaltenes, primarily neutral resins, make the basic contribution to the inhibiting effect. __________ Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 1, pp. 26–28, January–February, 2006.     

Heating self-interaction mechanism of surface magnetoplasma waves in plasma-like medium bounded by metal

The influence of electron heating in the high-frequency surface magnetoplasma wave(SM) field on dispersion properties of the considered SM is investigated. High frequency SM propagate at the interface between a plasma like medium with a finite electrons pressure and a metal. The nonlinear dispersion relation for the SM is derived and investigated.     

3-Orders-of-magnitude density control of single-walled carbon nanotube networks by maximizing catalyst activation and dosing carbon supply

Tailoring the density of random single-walled carbon nanotube (SWCNT) networks is of paramount importance for various applications, yet it remains a major challenge due to the insufficient catalyst activation in most growth processes. Here we report on a simple and effective method to maximise the number of active catalyst nanoparticles using catalytic chemical vapor deposition (CCVD). By modulating short pulses of acetylene into a methane-based CCVD growth process, the density of SWCNTs is dramatically increased by up to three orders of magnitude without increasing the catalyst density and degrading the nanotube quality. In the framework of a vapor-liquid-solid model, we attribute the enhanced growth to the high dissociation rate of acetylene at high temperatures at the nucleation stage, which can be effective in both supersaturating the larger catalyst nanoparticles and overcoming the nanotube nucleation energy barrier of the smaller catalyst nanoparticles. These results are highly relevant to numerous applications of random SWCNT networks in next-generation energy, sensing and biomedical devices.     

Microplasmas for Advanced Materials and Devices

Microplasmas are low-temperature plasmas that feature microscale dimensions and a unique high-energy-density and a nonequilibrium reactive environment, which makes them promising for the fabrication of advanced nanomaterials and devices for diverse applications. Here, recent microplasma applications are examined, spanning from high-throughput, printing-technology-compatible synthesis of nanocrystalline particles of common materials types, to water purification and optoelectronic devices. Microplasmas combined with gaseous and/or liquid media at low temperatures and atmospheric pressure open new ways to form advanced functional materials and devices. Specific examples include gas-phase, substrate-free, plasma-liquid, and surface-supported synthesis of metallic, semiconducting, metal oxide, and carbon-based nanomaterials. Representative applications of microplasmas of particular importance to materials science and technology include light sources for multipurpose, efficient VUV/UV light sources for photochemical materials processing and spectroscopic materials analysis, surface disinfection, water purification, active electromagnetic devices based on artificial microplasma optical materials, and other devices and systems including the plasma transistor. The current limitations and future opportunities for microplasma applications in materials related fields are highlighted.     

Controlling the adsorption behavior of hydrogen at the interface of polycrystalline CVD graphene

Polycrystalline graphene films were synthesized from renewable biomaterials in ambient air using a facile and rapid thermal chemical vapour deposition technique. Characterization of the graphene reveals a large surface area, the presence of nanoscale domains and open edges, atomic-level stacking, and high electrical conductivity, which are favorable features for electrochemical hydrogen evolution reactions (HERs). The numerous boundaries and open edges accelerate the gas diffusion process and enlarge the effective reactive surface area for gas evolution, which is responsible for a signi?cant improvement of HER performance and stability compared to a commercial graphene film. The hydrogen adhesion behavior in investigated for both bare Ni foil/foam and graphene grown on Ni foil/foam samples. The hydrogen gas bubbles adhere to the polycrystalline graphene for a long period of time before detaching, in contrast to their behavior on the pristine Ni foil surface. Post treatment of the graphene film using plasma treatment increases the desorption rate of hydrogen bubbles from the surface. The results indicate a wide range of possibilities for use of graphene-based catalysts in electrocatalytic gas evolution reactions.     

Use of Reagents to Decontaminate Operating Engine Oil and Lubrication Systems

Chemistry and Technology of Fuels and Oils - The use of fuels and oils that deviate from the relevant standards leads to a build-up of deposits in oil and on engine parts, reducing the service life...     

Plasma-enabled,catalyst-free growth of carbon nanotubes on mechanically-written Si features with arbitrary shape

Simple, rapid, catalyst-free synthesis of complex patterns of long, vertically aligned multiwalled carbon nanotubes, strictly confined within mechanically-written features on a Si(1 0 0) surface is reported. It is shown that dense arrays of the nanotubes can nucleate and fully fill the features when the low-temperature microwave plasma is in a direct contact with the surface. This eliminates additional nanofabrication steps and inevitable contact losses in applications associated with carbon nanotube patterns.     

Made-to-order nanocarbons through deterministic plasma nanotechnology

Through a combinatorial approach involving experimental measurement and plasma modelling, it is shown that a high degree of control over diamond-like nanocarbon film sp3/sp2 ratio (and hence film properties) may be exercised, starting at the level of electrons (through modification of the plasma electron energy distribution function). Hydrogenated amorphous carbon nanoparticle films with high percentages of diamond-like bonds are grown using a middle-frequency (2 MHz) inductively coupled Ar+CH4 plasma. The sp3 fractions measured by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy in the thin films are explained qualitatively using sp3/sp2 ratios 1) derived from calculated sp3 and sp2 hybridized precursor species densities in a global plasma discharge model and 2) measured experimentally. It is shown that at high discharge power and lower CH4 concentrations, the sp3/sp2 fraction is higher. Our results suggest that a combination of predictive modeling and experimental studies is instrumental to achieve deterministically grown made-to-order diamond-like nanocarbons suitable for a variety of applications spanning from nano-magnetic resonance imaging to spin-flip quantum information devices. This deterministic approach can be extended to graphene, carbon nanotips, nanodiamond and other nanocarbon materials for a variety of applications.