Nitrogen-Bearing Carbon Nanoparticles by Pyrolytic Decomposition of Piperazine Citrate Macromolecules for Cellular Imaging

In this work, highly photoluminescent carbon nanoparticles (CNPs) are fabricated by pyrolytic decomposition of piperazine citrate at high pressure and high temperature. Piperazine serves as a hydrolytic, surface-passivating, and N-doping agent, facilitating the formation of a photopolymer. The as-synthesized CNPs, without any surface protection/passivation, exhibit excellent photolumi-nescence and a maximum quantum yield of 84%. The average particle size of the N-doped CNPs is 0.89±0.05 nm. In addition, the N-doped CNPs exhibit uniform diameters and nearly spherical shapes. The X-ray photoelectron spectroscopy results reveal that the CNPs are composed of carbon (64.4 wt%), oxygen (18.5 wt%), and nitrogen (17.1 wt%), indicating the presence of nitrogen-doped and carbon-rich moieties in the CNPs. Notably, the CNPs purified by the procedure developed in this work exhibit more stable luminescence properties than those purified with the conventional dialysis membrane. In addition, the potential application of the CNPs as fluorescent bioimaging probes, which offer a broad dosing window and exhibit multicolor emission, is investigated by directly cultur-ing A549 cells with the CNPs. The results reveal that the CNPs exhibit not only exceptional optical stability, but also outstanding biocompatibility and cell labeling capability. After incubating the A549 cells with CNPs, the CNPs are confined in perinuclear vacuole-similar shapes with a granulated form in cytoplasm preserving the nucleus. Notably, no significant morphological deterioration such as nuclear contraction is detected.

Substantiation of Polymer Materials for the Use in Plow Constructions

The purpose of the work is to study and determine material "TEKRONE" belonging to the group of polymers, substantiate such a polymer composite material (PCM) in the modernization of the plow blade, which is not inferior to the "TEKRONE" composite and is much cheaper. This requires the study of the physical and mechanical properties of the material. The following studies of the physical and mechanical properties of the "TEKRONE" material have been conducted: density, heat endurance, and tensile strength. It has been found out that when heated over an open flame, the polymer softens with subsequent melting. There is no charring, destruction in the solid state. Therefore, the TEKRONE material is a thermoplastic. After pyrolytic decomposition 0.5… 0.7% of the initial sample weight remains. PCM TEKRONE density is 954 kg/m3. The value of this parameter coincides with the polyethylene density, which, depending on the brand, varies from 910 to 980 kg/m3. The tensile strength stress of the investigated samples of PCM TEKRONE is 17.9 MPa, which is very close to the values of polyethylene (14.8-17.0 MPa). The laboratory studies have shown that TEKRONE polymer-composite material in its properties corresponds to the materials based on polyethylene. It is determined that the closest in properties are PE 500 and PE 1000 polyethylene. It is advisable to recommend the use of PE 500 and PE 1000 polyethylene as a basis for the manufacture of plow blade of PLN type.

Vacuum Pyrolysis of Waste Vehicle Tyres into Oil Fuel Using A Locally, Fabricated Reactor

Some countries still face daunting challenges of managing ever-increasing waste generated, especially plastic and waste vehicle tyres. Whilst some developed countries have adopted innovative ways such as catalytic or pyrolytic decomposition processes for energy or fuel generation from these wastes, developing countries like Ghana still dispose off indiscriminately around communities or un-engineered dumpsites. Hence, this study sought to transform waste vehicle tyres into fuel which invariably minimises or eliminates its environmental impact. Particularly, waste vehicle tyres (sourced from dumpsites in Tarkwa, Ghana) were washed, shredded and decomposed via pyrolysis at high temperature range (~ 450 - 650 oC) using locally designed and fabricated reactor. The physicochemical properties (such as water content, flashpoint, density, sulphur content, solids and viscosity) of the pyrolysis oil produced were also examined using the American Society for Testing and Materials (ASTM) standards and procedures. The results showed that the viscosity, flashpoint and the density of the pyrolysis oil produced were 0.904 cSt, 34.5 oC, and 850.6 kg/m3 (at 15 oC), respectively. The sulphur, water and solids/particulates contents were 4340.0 ppm, 0.8 vol.%, and 483,495.5 ppm, respectively. It was also observed that the pyrolysis oil obtained appeared as thick, single-phase liquid with dark colour and strong odour at room temperature. Relatively, the properties of pyrolysis oil produced without further treatment did not meet the International specification for diesel fuel, hence its usage would require further treatments such as desulphurisation, decanting, centrifugation and filtration. Overall, the study has demonstrated that the pyrolysis of waste vehicle tyres into fuel provides an alternative method for managing end-of-life vehicle tyres and adding value to waste in general. Keywords: Pyrolysis, Waste Vehicle Tyres, Reactor, Pyrolysis Oil, Biofuel

Investigation of carbon deposition induced by pyrolytic decomposition of ethylene

We employed Raman spectroscopy to characterize the formed carbon deposits under different conditions inside a built-in U-shape quartz tube for unravelling mechanism of carbon deposition on stainless steel.

Thermal Degradation Behaviour of Ni(II) Complex of 3,4-Methylenedioxaphenylaminoglyoxime

Thermal degradation behaviour of the Ni(II) complex of 3,4-methylenedioxaphenylaminoglyoxime was investigated by TG, DTA, and DTG at a heating rate of 10°C min−1under dinitrogen. The acquired experimental data shows that the complex is thermally stable up to 541 K. The pyrolytic decomposition process occurs by melting metal complex and metal oxide remains as final product. The energies of the reactions involved and the mechanism of decomposition at each stage have been examined. The values of kinetic parameters such as activation energy (E), preexponential factor (A) and thermodynamic parameters such as enthalpy (ΔH), entropy (ΔS), and Gibbs free energy (ΔG) are also evaluated.