Different mass fractions （0, 5%, 10%, and 15%） of the synthesized nano SiC particles reinforced Ti-6Al-4V （Ti64） alloy metal matrix composites （MMCs） were successfully fabricated by the powder metallurgy method....Different mass fractions （0, 5%, 10%, and 15%） of the synthesized nano SiC particles reinforced Ti-6Al-4V （Ti64） alloy metal matrix composites （MMCs） were successfully fabricated by the powder metallurgy method. The effects of addition of SiC particle on the mechanical properties of the composites such as hardness and compressive strength were investigated. The optimum density （93.33%） was obtained at the compaction pressure of 6.035 MPa. Scanning electron microscopic （SEM） observations of the microstructures revealed that the wettability and the bonding force were improved in Ti64 alloy/5% nano SiCp composites. The effect of nano SiCp content in Ti64 alloy/SiCp matrix composite on phase formation was investigated by X-ray diffraction. The correlation between mechanical parameter and phase formation was analyzed. The new phase of brittle interfaced reaction formed in the 10% and 15% SiCp composite specimens and resulted in no beneficial effect on the strength and hardness. The compressive strength and hardness of Ti64 alloy/5% nano SiCp MMCs showed higher values. Hence, 5% SiCp can be considered to be the optimal replacement content for the composite.展开更多
An attempt was made to deposit thin film of silver onto the glass substrate by using Ag Cl precursor, instead of conventional precursor AgNO_3 with vitamin C by inexpensive and convenient successive ionic layer adsorp...An attempt was made to deposit thin film of silver onto the glass substrate by using Ag Cl precursor, instead of conventional precursor AgNO_3 with vitamin C by inexpensive and convenient successive ionic layer adsorption and reaction(SILAR) method. The deposited silver thin film was characterized by X-ray diffraction(XRD) analysis, scanning electron microscope(SEM), UV-visible and electrical I-V study. The diffraction study showed FCC structure of metallic silver in good agreement with the standard values of JCPDS(04–0783). SEM reveals flower like nano particles produced on the substrate. The surface plasmon resonance(SPR) peak in the UV-visible spectrum shows maximum absorption at 350 nm. The film shows an ohmic behavior and its electrical resistivity was found ~103 ?·cm at room temperature.展开更多
β-Ag2 Se and β-AgCuSe nanoparticles were synthesized using AgCl precursor instead of conventional AgNO3 by simple precipitation method.It was found that orthorhombic structures were obtained for both β-AgzSe and β...β-Ag2 Se and β-AgCuSe nanoparticles were synthesized using AgCl precursor instead of conventional AgNO3 by simple precipitation method.It was found that orthorhombic structures were obtained for both β-AgzSe and β-AgCuSe nanoparticles.The result shows Ag2 S as impurity while increasing the concentration of AgCl.Moreover,the microstructural images show polyhedraland pebble-like particles.The band gap energy is increased for β-AgzSe owing to small crystallite size.The AgC1 precursor can effectively produce pure nanoparticles.Hence,it is interesting in terms of identification of potential precursor for synthesizingβ-Ag2 Se and β-AgCuSe nanoparticles.展开更多
Grid-connected rooftop solar photovoltaic(PV)systems can reduce the energy demand from the grid and significantly increase the power available to it.However,rooftop solar PV has not yet been widely adopted in many sub...Grid-connected rooftop solar photovoltaic(PV)systems can reduce the energy demand from the grid and significantly increase the power available to it.However,rooftop solar PV has not yet been widely adopted in many sub-Saharan African countries,such as Sudan,although they are endowed with high solar radiation and in dire need of additional power.This paper investigates risks and policies to increase grid-connected rooftop solar PV adoption in Sudan.A simplified United Nations Development Program Derisking Renewable Energy Investment framework is adopted to investigate this over three stages.For Stage 1,a list of risks and barriers was produced based on a literature review of solar PV studies in Sudan and interviews with nine stakeholders.Affordability was the risk most often mentioned(eight times from nine interviewees),followed by concerns about poor utility grid infrastructure.For Stage 2,policy de-risking instruments and financial de-risking instruments were listed to overcome the barriers.These include the intro-duction of net metering,the use of a third-party organization to monitor policy implementation,upgrade of the grid infrastructure,public awareness campaigns and energy-saving schemes.For Stage 3,the levelized cost of electricity was estimated for a typical 2-kW rooftop PV system without policies(0.11$/kWh)and with a net-metering policy(0.07$/kWh).展开更多
基金CISL,Department of Physics,Annamalai University for the support in using AFM and SEM for experimentation
文摘Different mass fractions （0, 5%, 10%, and 15%） of the synthesized nano SiC particles reinforced Ti-6Al-4V （Ti64） alloy metal matrix composites （MMCs） were successfully fabricated by the powder metallurgy method. The effects of addition of SiC particle on the mechanical properties of the composites such as hardness and compressive strength were investigated. The optimum density （93.33%） was obtained at the compaction pressure of 6.035 MPa. Scanning electron microscopic （SEM） observations of the microstructures revealed that the wettability and the bonding force were improved in Ti64 alloy/5% nano SiCp composites. The effect of nano SiCp content in Ti64 alloy/SiCp matrix composite on phase formation was investigated by X-ray diffraction. The correlation between mechanical parameter and phase formation was analyzed. The new phase of brittle interfaced reaction formed in the 10% and 15% SiCp composite specimens and resulted in no beneficial effect on the strength and hardness. The compressive strength and hardness of Ti64 alloy/5% nano SiCp MMCs showed higher values. Hence, 5% SiCp can be considered to be the optimal replacement content for the composite.
基金the DST-FIST and UGC-SAP,New Delhi for providing the financial support to the Department of Physics,Manonmaniam Sundaranar University
文摘An attempt was made to deposit thin film of silver onto the glass substrate by using Ag Cl precursor, instead of conventional precursor AgNO_3 with vitamin C by inexpensive and convenient successive ionic layer adsorption and reaction(SILAR) method. The deposited silver thin film was characterized by X-ray diffraction(XRD) analysis, scanning electron microscope(SEM), UV-visible and electrical I-V study. The diffraction study showed FCC structure of metallic silver in good agreement with the standard values of JCPDS(04–0783). SEM reveals flower like nano particles produced on the substrate. The surface plasmon resonance(SPR) peak in the UV-visible spectrum shows maximum absorption at 350 nm. The film shows an ohmic behavior and its electrical resistivity was found ~103 ?·cm at room temperature.
基金the DST-FIST,UGC-SAP,New Delhi,India,for providing the financial support to the Department of Physics,Manonmaniam Sundaranar University,Tirunelveli,Tamil Nadu,India
文摘β-Ag2 Se and β-AgCuSe nanoparticles were synthesized using AgCl precursor instead of conventional AgNO3 by simple precipitation method.It was found that orthorhombic structures were obtained for both β-AgzSe and β-AgCuSe nanoparticles.The result shows Ag2 S as impurity while increasing the concentration of AgCl.Moreover,the microstructural images show polyhedraland pebble-like particles.The band gap energy is increased for β-AgzSe owing to small crystallite size.The AgC1 precursor can effectively produce pure nanoparticles.Hence,it is interesting in terms of identification of potential precursor for synthesizingβ-Ag2 Se and β-AgCuSe nanoparticles.
文摘Grid-connected rooftop solar photovoltaic(PV)systems can reduce the energy demand from the grid and significantly increase the power available to it.However,rooftop solar PV has not yet been widely adopted in many sub-Saharan African countries,such as Sudan,although they are endowed with high solar radiation and in dire need of additional power.This paper investigates risks and policies to increase grid-connected rooftop solar PV adoption in Sudan.A simplified United Nations Development Program Derisking Renewable Energy Investment framework is adopted to investigate this over three stages.For Stage 1,a list of risks and barriers was produced based on a literature review of solar PV studies in Sudan and interviews with nine stakeholders.Affordability was the risk most often mentioned(eight times from nine interviewees),followed by concerns about poor utility grid infrastructure.For Stage 2,policy de-risking instruments and financial de-risking instruments were listed to overcome the barriers.These include the intro-duction of net metering,the use of a third-party organization to monitor policy implementation,upgrade of the grid infrastructure,public awareness campaigns and energy-saving schemes.For Stage 3,the levelized cost of electricity was estimated for a typical 2-kW rooftop PV system without policies(0.11$/kWh)and with a net-metering policy(0.07$/kWh).
