Papers by Keyword: Carbon Layer

Abstract: The carbonate precipitate of sugar production from sugar beet is a large-tonnage organic waste, the disposal of which is a significant problem for many agricultural regions. According to studies, the temperature of maximum combustion is 506.1 ° С for carbonate precipitate, the carbon content in TMCP₆₀₀ was about 2%, CaCO₃ 94-95%, sand and clay impurities 3-4%. The presence of multiple bonds (modifications C8, C70 and C80) in carbon layer of TMCP₆₀₀ particles is confirmed by studies of the IR spectrum and the interaction with iodine water. The internal structure of the carbon layer formed is similar to traditional carbon sorbents, such as KAD grade activated carbon. With increasing roasting temperature of a carbonate precipitate, the pH of the aqueous extract increases, which confirms the process of decomposition of the calcium salts of carboxylic acids. The specific surface area of ​​the sorption material, measured by the method of low-temperature nitrogen adsorption, was 82 ± 0.2 m²/ g.

Abstract: Phosphate-based cathode material, LMP, with olivine crystal structure is generally known as cathode material with low electronic conductivity. Therefore, these materials should be coated by conductive materials. In this study the synthesis of carbon-coated cathode material and dopant variations in cathode material to improve the working potential of the battery are observed. The process of synthesis is carried out through the conventional solid-state process. The starting materials, Li₂CO₃, MnO₂, Fe, Ni and NH₄H₂PO₄ in the powder form are mixed homogenously. The homogeneous mixture is further mixed with a solution of in water dissolved citric acid. This is then dried in oven for 24 hours. The dry mixture is then heated at a temperature of 320°C for 10 hours in a furnace with an inert atmosphere. The obtained powder is subsequently heated at 800°C for 8 hours in the furnace with flowing nitrogen gas. Phase of the powder obtained after the second heating was analyzed by XRD. Phase compositions were analyzed by Rietveld refinement method through a GSAS-software. Analysis of the microstructure and morphology are performed by SEM and BET. Cathode material performance is analyzed by using the Charge-Discharge battery analyzer. To perform Charge-Discharge analysis, cathode material is assembled into a half cell with metallic lithium as the counter electrode and 1 M LiPF6 dissolved in EC: DEC (1: 1 v / v) as the electrolyte.

Abstract: Copper-tungsten alloy which is widely used in the field of EDM has high melting temperature and excellent electrical and thermal conductivity. Copper tungsten electrodes for electrical discharge dressing of metal-bond wheel were studied, and experiments were conducted to observe their wear performance in this paper. Orthogonal experiment was designed to explore the wear at the edge of and the bottom of electrode with the machining of holes. Thickness of the carbon layer, micro topography and experimental results were analyzed. Low current and big pulse duration can reduce the electrode wear rate. Although carbon on the electrode surface can be wiped out easily, wear rate of copper-tungsten electrode decreases with the increasing in thickness of the carbon at the initial phase. There are fewer cracks and residue presented on the machined surface by microscope.

Abstract: Polymers with modified surface structure are useful for medicine applications. This study is focused on the surface properties of polymers with carbon layers and their biocompatibility. For experiments was used polyethyleneterephtalate (PET). We used magnetron sputtering for producing of the carbon layers. Raman spectroscopy, goniometry, AFM – microscopy, X-ray diffraction and infrared spectroscopy were used in our experiments to describe the physicochemical properties of modified polymers. Biocompatibility of structure polymer-carbon layers was studied with method in vitro. We investigated adhesion of mouse 3T3-fibroblasts. The carbon layers have positive influence on biocompatibility.