Papers by Keyword: CuO

Abstract: A typical Nebulizer Spray Pyrolysis (NSP) technology was used to produce and deposit CuO nanoparticles on glass substrates. In this work, the effects of different precursor volumes on the properties of CuO thin films produced by Nebulizer Spray Pyrolysis (NSP) were investigated. In this work, CuO thin films have been developed using the NSP approach with three different precursor quantities (3, 4, and 5 ml). A monoclinic crystal structure was found using X-ray diffractometry (XRD), which was confirmed to be consistent with JCPDS card No. (89-5899). The XRD studies have been used to calculate the dislocation density, micro strain, and crystallite size. The average thickness was measured using a surface profilometer. High-resolution Schottky emitter FE-SEM has been used to study morphological properties, and the results demonstrate that each film has been evenly deposited on the glass substrate. The presence of the element in the CuO thin films has been confirmed by energy dispersive X-ray analysis (EDAX). Transmission values ranging from 20% to 65% at varied volumes were achieved, according to the optical measurements. The energy band gaps were determined using tauc plots to be between 1.85 eV and 2.15 eV, with 4 ml having the lowest band gap value at 1.85 eV. CuO thin-film’s electrical conductivity was measured in DC, and the highest conductivity value for 4ml was 2.5x10^-8 S/cm.

Abstract: Scientists from a variety of fields have joined forces to study a world so small that it cannot be seen with the naked eye, not even under a light microscope. That is the domain of nanotechnology, the universe of atoms and nanostructures. Anything between 1 and 100 nm in size is generally considered to be within the purview of nanotechnology, despite the occasional disagreement among experts regarding precisely what is included in the nanoscale. That is not the atomic scale and the microscale is still larger. This paper will define nanotechnology and discuss its potential future applications. The application of nanoparticles in one of the mechanical engineering field's most significant uses will also be reviewed. The Vapor Compression Refrigeration System (VCRS) uses nanobased refrigerants to deliver a better, faster cooling process with less power consumption. resulting in the provision of a healthier environment and a more effective system.

Abstract: In this research work, brass (Cu - 37.2 wt% Zn) and Cu (99.9 wt%) wires having diameters of 200 μm were thermally oxidized in N₂ containing 5% O₂, at a flow rate of 200 sccm and in the ambient atmosphere respectively, to support the growth of nanowires. The oxidation temperature was varied from 300 to 600 °C and the as-grown nanowires were characterized by field emission scanning electron microscope (FESEM) equipped with energy dispersive X-ray (EDX) spectroscope, and transmission electron microscope (TEM). Results show that ZnO and CuO nanowires are formed on brass and Cu wires, respectively. The ZnO nanowires are branched and CuO nanowires are straight with tapered morphology. ZnO nanowires having hexagonal wurtzite structure grow along the <1 1 0> directions whereas, CuO nanowires have monoclinic structure. A diffusion based stress induced model is proposed to explain the growth mechanism of the nanowires. Thermal oxidation process is a suitable platform for synthesizing ZnO and CuO nanowires, which can be used in in-situ device fabrication.

Abstract: A series of single carbon source and metal oxide assisted carbon source were prepared by mechanochemical process followed by carbothermal reduction which obtained via the reaction between activated carbon (AC) from rubber wood sawdust (Havea brasiliensis) and CuO precussor. Microstructure of the single AC and CuO assisted AC (CuO-AC) has been studied using Field Emission Scanning Electron Microscopy (FESEM). The products were further characterized using X-ray diffraction (XRD) and thermal analysis (TG and DTA). A significant difference of the microstructure between AC and CuO-AC samples were observed in FESEM micrograph. The micrograph of single AC in indicates porous structure with numerous pores present due to dehydration of volatile matters. Milling process and reduction of CuO by AC has contributed to the increasing formation of porous structure with nanopore size ranging from 100-200 nm. TG and DTA results revealed that single AC and CuO-AC have a significant difference in thermal decomposition and stability. Doping of CuO to AC has affected the exothermic and endothermic reaction of the samples. These were further being clarified by X-ray diffraction where phase analysis is studied. It was found that the addition of CuO to AC brought a significant increase in the degree of crystallinity which is accompanied by mechanochemical process followed by carbothermal reduction to produce Cu. Incomplete reduction also cause the formation of Cu₂O. Production of CuO-AC were successfully characterized and revealed the potential enhancement for waste treatment.

Abstract: Mechanochemical process was conducted to synthesis a series of metal oxide doped biomass carbon source followed by carbothermal reduction which obtained via the reaction between activated carbon (AC) and CuO precursor. Microstructure of single AC and CuO-doped activated carbon was conducted using Field Emission Scanning Electron Microscopy (FESEM). Thermal behavior was studied using thermogravimetric analyser and Differential Scanning Calorimetry (TGA and DSC) and crystallinity phase was analysed using X-ray diffraction (XRD). The results indicated that mechanochemical process and carbothermal reduction to synthesis CuO-doped AC have a significant effect in term of surface morphology, thermal decomposition and crystallinity. A significant difference of the surface morphology between AC and CuO-AC samples were observed. TGA/DSC analysis revealed that doping of CuO to AC has affected the exothermic and endothermic reaction of the samples. Doping of CuO to AC also brought a significant increase in the degree of crystallinity due to the carbothermal reduction of CuO into Cu. Production of CuO-doped AC was successfully characterized and revealed the potential enhancement for waste treatment.

Abstract: This work presents and discusses the anitwear characteristics of surface modified CuO nanoparticle suspensions in bio-based lubricant. 1.0 wt% unmodified as well as surface modified CuO nanoparticles (nominal size of 50 nm), were dispersed in base oil using an ultrasonic probe. Wear protection was evaluated by using Four-Ball Extreme Pressure (EP) testing and sliding wear tests. The scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) analysis of the worn surface shows that: surface modification helped to improve the dispersion stability of CuO nanoparticles and related suspension show high EP characteristics in terms of load wear index and low cylinder liner wear due to surface mending effect of nanoparticles.

Abstract: Hybrid nanofluid is the new generation of heat transfer fluid for various heat transfer applications where transport characteristics are substantially higher than the base liquid. The study presents an experimental investigation of rheological and thermophysical properties of Al₂O₃/ CuO hybrid nanoparticles suspended in 25:75 (by weight) ethylene glycol and water mixture. This manuscript presents experimental work of thermophysical properties of Al₂O₃/CuO/water/ethylene glycol hybrid nanofluids and its effect on thermal efficiency of flat plate solar collector. Nanofluids of particle volume percentage of 0.5%, 1%, 1.5% and 2% were tested. Results show that thermal conductivity, viscosity and density increases with nanoparticles concentration. The efficiency of the collector was improved by 45% by increasing the nanoparticle weight fraction.

Abstract: Our work consists to the deposition of copper oxide (CuO) thin films onto glass substrates by the spray pyrolysis method. The precursor solution was copper chloride of 0.1 M and the deposition rate was 5 ml/h. The time of spray varied between 5 and 20 min and the substrate temperature was kept at 350°C. The structural, optical and electrical properties of CuO films were investigated, as a function of the spray time, by X-ray diffraction (XRD), Raman scattering, UV-visible spectroscopy in addition to the measurements of the thickness and the electrical resistivity. The obtained results indicated that our films were polycrystalline with a preferential orientation along the (111) planes. The peaks intensity as well as the grain size increased as a function of the spray time indicating the improvement of the films crystalline structure. The Raman spectroscopy confirmed the formation of the CuO phase. The UV-visible transmission varied between 36% and 53% and the band gap energy decreased from 2 to 1.72 eV as a function of the spray time. The electrical resistivity of the films decreased from 514 to 72 kΩcm and correlated with the decrease of the band gap energy and the increase of the grain size.

Abstract: Co/Cr co-doped in soda lime silicate (SLS) glasses were prepared by using normal melt quenching technique. The current composition was prepared based on the proposed ratio: (64.9-x)SiO₂: 10CaO: 25Na₂O: 0.1CuO: xCoO where x=0.00, 0.01, 0.02, 0.03, 0.04 and 0.05 mol% were prepared at 1200°C for 3 h, and annealed at 500 °C for 3 h. The physical and optical properties of Co/Cr co-doped in SLS glasses were investigated such as density, molar volume, refractive index and optical absorption were discussed and measured. The optical absorption spectrum of Co/Cr co-doped in SLS glasses measured at room temperature in the wavelength region 200–1100 nm were presented.

Abstract: A simple method for the separation of aqueous methyl orange, an azo dye, is reported, where CuO/CuAl2O4 nanoparticles synthesisedby co-precipitation methodwere used as the adsorbent. The presence of cubic CuAl2O4 (CAO) and monoclinic CuO phase of this composite material was confirmed by X-Ray diffraction and its specific surface area wasdetermined by BET nitrogen adsorption method.To study the nature of surface charge, theisoelectric point of the material was determined using the pH drift methodfollowing which the rate of decolouration was studied forpH 5and pH 7. Theexperiments in the absence oflight show that adsorption of the dye is prevalent even up to 6h leading to 86% decolouration.A methanolic extraction was effectivefor quantitative separation ofadsorbed dye fromCuO/CuAl2O4 nanoparticles regenerating them for reuse. The presence of methyl orange in the extracted solution and on the nanoparticles at various stages was verified byUV-Visible and FT-IR spectroscopic methods.The extent of adsorption was quantified and found tobe as high as 86%. The catalyst aftercomplete extraction ofmethyl orange (MO),could be reused for the decolouration. Stability of the nanoparticles after reuse was verified by the closematch of XRD patterns ofthe pure and reused CAOwhich show no significant changes in itscrystal structure. The separation method shown here can be extended for the removal of other azo dyesfrom textile effluents.