3d transition metal oxides based thin film coatings such as copper–cobalt oxides exhibit high absorption in the visible region and low emittance in the infrared to far-infrared region of the solar spectrum which is f...3d transition metal oxides based thin film coatings such as copper–cobalt oxides exhibit high absorption in the visible region and low emittance in the infrared to far-infrared region of the solar spectrum which is favourable for use as potential selective surface materials in photothermal devices. These materials have the potential to minimize heating while increasing absorption in the operative spectrum range and therefore achieve higher solar selectivity. A series of mixed copper–cobalt metal spinel oxides（Cu_xCo_yO_z）doped with graphene oxide thin films were deposited on commercial grade aluminium substrates using a sol-gel dip-coating technique at an annealing temperature of 500 °C in air for 1 h. Characterizations of the synthesized films were carried out by high temperature synchrotron radiation X-ray Diffraction（SRXRD）, UV–Vis, Fourier Transform infrared spectroscopy（FTIR） and X-ray photoelectron microscopy（XPS）techniques. High thermal stability of coatings with multiple phases, binary and ternary metal oxides, was defined through SR-XRD study. FTIR analysis shows moderate（〈80%） to high（up to 99%） reflectance in the infrared region while the UV–Vis investigations demonstrate that, in the visible region, solar absorption increases gradually（up to 95%） with the addition of graphene oxide to the Cu_x Co_y O_z coatings.With the incorporation of 1.5 wt.% of graphene oxide to the copper–cobalt oxide coatings, a high solar selectivity of 29.01（the ratio of the average solar absorptance in visible and the average thermal emittance in infrared to far infrared region; α/ε） was achieved.展开更多
The present work involves in the construction of a vertical axis wind turbine and the determination of power. Various different types of turbine blades are considered and the optimum blade is selected. Mechanical comp...The present work involves in the construction of a vertical axis wind turbine and the determination of power. Various different types of turbine blades are considered and the optimum blade is selected. Mechanical components of the entire setup are built to obtain maximum rotation per minute. The mechanical energy is converted into the electrical energy by coupling coaxially between the shaft and the generator. This setup produces sufficient power for consumption of household purposes which is economic and easily available.展开更多
基金Murdoch International Postgraduate Research Scholarship(MIPRS)programme in carrying out his Ph D researchAustralian Synchrotron for providing Powder Diffraction beamtime(AS141/PD/7582)+1 种基金supported by the Teesside University Research Fund(URF)funding support provided by IRU-MRUN Collaborative Research Program-2015
文摘3d transition metal oxides based thin film coatings such as copper–cobalt oxides exhibit high absorption in the visible region and low emittance in the infrared to far-infrared region of the solar spectrum which is favourable for use as potential selective surface materials in photothermal devices. These materials have the potential to minimize heating while increasing absorption in the operative spectrum range and therefore achieve higher solar selectivity. A series of mixed copper–cobalt metal spinel oxides（Cu_xCo_yO_z）doped with graphene oxide thin films were deposited on commercial grade aluminium substrates using a sol-gel dip-coating technique at an annealing temperature of 500 °C in air for 1 h. Characterizations of the synthesized films were carried out by high temperature synchrotron radiation X-ray Diffraction（SRXRD）, UV–Vis, Fourier Transform infrared spectroscopy（FTIR） and X-ray photoelectron microscopy（XPS）techniques. High thermal stability of coatings with multiple phases, binary and ternary metal oxides, was defined through SR-XRD study. FTIR analysis shows moderate（〈80%） to high（up to 99%） reflectance in the infrared region while the UV–Vis investigations demonstrate that, in the visible region, solar absorption increases gradually（up to 95%） with the addition of graphene oxide to the Cu_x Co_y O_z coatings.With the incorporation of 1.5 wt.% of graphene oxide to the copper–cobalt oxide coatings, a high solar selectivity of 29.01（the ratio of the average solar absorptance in visible and the average thermal emittance in infrared to far infrared region; α/ε） was achieved.
文摘The present work involves in the construction of a vertical axis wind turbine and the determination of power. Various different types of turbine blades are considered and the optimum blade is selected. Mechanical components of the entire setup are built to obtain maximum rotation per minute. The mechanical energy is converted into the electrical energy by coupling coaxially between the shaft and the generator. This setup produces sufficient power for consumption of household purposes which is economic and easily available.
