Search results
1 – 4 of 4Liliya Frolova and Olga Sergeyeva
This paper aims to develop a simple and efficient plasma technology for the production of copper (I) oxide with the ability to control the morphology and size of Cu2O particles…
Abstract
Purpose
This paper aims to develop a simple and efficient plasma technology for the production of copper (I) oxide with the ability to control the morphology and size of Cu2O particles. To achieve this goal, the phase composition of the precipitate formed was estimated, the composition and size of the obtained particles were determined and Pourbaix diagrams were constructed.
Design/methodology/approach
An integrated approach combining thermodynamic calculations and experimental research methods is used. The constructed Pourbaix diagram makes it possible to suggest the phase composition of the sediment. The use of cyclic voltammetry made it possible to establish the mechanism of deposit formation on the cathode during the treatment of the solution with contact nonequilibrium low-temperature plasma. The resulting product was examined using X-ray phase analysis and scanning electron microscopy.
Findings
The article presents the results of theoretical and experimental studies on the synthesis of copper (II) oxide. The influence of the parameters of plasma-chemical synthesis on the shape and phase composition of the deposits formed has been studied.
Originality/value
A plasma-chemical technology for obtaining copper oxide in the form of single crystals of a regular faceted shape is proposed. The mechanism of formation of copper oxide has been established by cyclic voltammetry. The constructed Pourbaix diagrams show the area of existence of the product.
Details
Keywords
Deepak Byotra and Sanjay Sharma
This study aims to understand how the texture shape, number of textures and addition of nanoparticle additives in lubricants impact the dynamic characteristics of journal bearing…
Abstract
Purpose
This study aims to understand how the texture shape, number of textures and addition of nanoparticle additives in lubricants impact the dynamic characteristics of journal bearing by comparing six different texture shapes like triangle, chevron, arc, circle, rectangle and elliptical applied in pressure-increasing region under various geometrical and operating conditions.
Design/methodology/approach
The finite element method approach has been employed to solve governing Reynold’s equation, assuming iso-viscous Newtonian fluid, for computation of performance parameters like stiffness and damping coefficient, threshold speed, etc. By using a regression model, the impact of adding nanoparticles Al2O3 and CuO to the base lubricant on viscosity variation is calculated for selected temperature ranges and weight fractions of nanoparticles.
Findings
The arc-shaped texture with an area density of 28.27%, eccentricity ratio of 0.2 and texture depth of 0.6 exhibited 35.22% higher direct stiffness and 41.4% higher damping coefficient compared to the lowest value in the circle-shaped texture. Increasing the number of arc-shaped textures on the bearing surface with low area density led to declining stiffness and damping parameters. However, with nanoparticle additives, the arc-shaped texture further showed 10.75% and 8.11% improvement in stiffness and 9.99% and 4.87% enhancement in damping coefficient for Al2O3 and CuO, respectively, at 90 °C temperature and 0.5% weight fraction.
Originality/value
By understanding the influence of texture shapes on the dynamic characteristics, engineers can design bearings that exhibit improved stability and enhance overall performance.
Details
Keywords
Aurang Zaib, Rizwan Ul Haq, Ali J. Chamkha and Mohammad Mehdi Rashidi
The purpose of this paper is to present an inclusive study of the mixed convective flow involving micropolar fluid holding kerosene/water-based TiO2 nanoparticle towards a…
Abstract
Purpose
The purpose of this paper is to present an inclusive study of the mixed convective flow involving micropolar fluid holding kerosene/water-based TiO2 nanoparticle towards a vertical Riga surface with partial slip. The outcomes are confined for opposing and assisting flows.
Design/methodology/approach
Similarity equations are acquired and then worked out numerically by the Keller box technique.
Findings
Impacts of significant parameters on microrotation velocity, temperature distribution, velocity profile together with the Nusselt number and the skin friction are argued with the help of graphs. Two solutions are achieved in opposing flow, while the solution is unique in assisting flow. It is also monitored that the separation of boundary layer delays because of micropolar parameter and accelerates because of volume fraction.
Originality/value
The authors trust that all these results are new and significant for researchers.
Details
Keywords
Sanjeev Kumar, Narendra K. Verma and Madan L. Singla
The purpose of this paper is to investigate the reflective properties of titania (TiO2) nanoparticle‐based coating.
Abstract
Purpose
The purpose of this paper is to investigate the reflective properties of titania (TiO2) nanoparticle‐based coating.
Design/methodology/approach
TiO2 nanoparticles, synthesised by sol‐gel method, were characterised by X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and ultraviolet‐visible absorption spectroscopy (UV‐vis). The coating material has been prepared by dispersing titania nanoparticles in an acrylic binder with different pigment to binder weight ratio. The reflectors were prepared by applying this coating material to different coating thicknesses to aluminium sheets.
Findings
In the study reported here, the coating material could produce reflectors with diffuse reflectance, ∼99 per cent, using coating material, having binder by weight ratio between 14 and 20 per cent, and thickness, 0.15 mm. On exposing the developed reflectors to different levels of illumination (upto 20,000 lux), they were still found to have diffuse reflectance of more than 96 per cent almost throughout the visible spectrum.
Practical implications
The fabricated reflectors find applications in commercial optical products, such as: reflective panels, luminaries, etc.
Originality/value
As of today, the reflective coatings used are of conventional type, which employ bulk TiO2 particles. In this study, we are reporting TiO2 nanoparticle‐based highly reflective coating. This is an original work, and, to the best of our knowledge, no one has ever reported on “TiO2 nanoparticle‐based reflective coatings”.
Details