The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Zafar Said - One of the best experts on this subject based on the ideXlab platform.
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energy and exergy analysis of a flat plate solar collector using different sizes of Aluminium Oxide based nanofluid
Journal of Cleaner Production, 2016Co-Authors: Zafar Said, R Saidur, N A RahimAbstract:Abstract Growing dependence of industry and technology on fossil energy and increasing population encounters all countries with challenge of energy for future. Therefore, investigation about renewable energies, particularly solar energy is considered. The use of nanofluids in solar collectors offers better performance, as they are very efficient in transporting heat even under small temperature difference. The effect of Aluminium Oxide (Al 2 O 3 )–water nanofluid, as working fluid, is used to evaluate the thermal efficiency of a flat plate solar collector, experimentally. A volume fraction of 0.1% for size of (13 nm and 20 nm) nanoparticles, respectively was used for this study. The mass flow rates of the nanofluid varied from 0.5 to 1.5 kg/min. Experiments were carried out using a stable nanofluid. The stability of nanofluid was obtained by controlling the pH of the solution. An ASHRAE Standard 93-2010 (R2014) was used to analyze efficiency of the solar collector. The results reflect the contribution and significance of each of these parameters to the collector overall energetic and exergetic efficiencies. Two different sizes of Al 2 O 3 –water nanofluid 13 nm and 20 nm are examined, and results show that 13 nm Al 2 O 3 nanofluid shows higher thermal conductivity enhancement and efficiency, compared to that of 20 nm Al 2 O 3 nanofluid and water. Al 2 O 3 –H 2 O (13 nm) nanofluid with 0.1% volume fraction and at a flow rate of 1.5 kg/min showed the highest energy efficiency of about 73.7%, compared to Al 2 O 3 –H 2 O (20 nm) nanofluid, which showed an energy efficiency of 70.7%. Critical point of Al 2 O 3 –water nanofluid is also presented, which has not be reported in literature according to author's knowledge, which also shows the novelty of this work.
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energy and exergy analysis of a flat plate solar collector using different sizes of Aluminium Oxide based nanofluid
Journal of Cleaner Production, 2016Co-Authors: Zafar Said, R Saidur, N A RahimAbstract:Abstract Growing dependence of industry and technology on fossil energy and increasing population encounters all countries with challenge of energy for future. Therefore, investigation about renewable energies, particularly solar energy is considered. The use of nanofluids in solar collectors offers better performance, as they are very efficient in transporting heat even under small temperature difference. The effect of Aluminium Oxide (Al 2 O 3 )–water nanofluid, as working fluid, is used to evaluate the thermal efficiency of a flat plate solar collector, experimentally. A volume fraction of 0.1% for size of (13 nm and 20 nm) nanoparticles, respectively was used for this study. The mass flow rates of the nanofluid varied from 0.5 to 1.5 kg/min. Experiments were carried out using a stable nanofluid. The stability of nanofluid was obtained by controlling the pH of the solution. An ASHRAE Standard 93-2010 (R2014) was used to analyze efficiency of the solar collector. The results reflect the contribution and significance of each of these parameters to the collector overall energetic and exergetic efficiencies. Two different sizes of Al 2 O 3 –water nanofluid 13 nm and 20 nm are examined, and results show that 13 nm Al 2 O 3 nanofluid shows higher thermal conductivity enhancement and efficiency, compared to that of 20 nm Al 2 O 3 nanofluid and water. Al 2 O 3 –H 2 O (13 nm) nanofluid with 0.1% volume fraction and at a flow rate of 1.5 kg/min showed the highest energy efficiency of about 73.7%, compared to Al 2 O 3 –H 2 O (20 nm) nanofluid, which showed an energy efficiency of 70.7%. Critical point of Al 2 O 3 –water nanofluid is also presented, which has not be reported in literature according to author's knowledge, which also shows the novelty of this work.
D Sheeja - One of the best experts on this subject based on the ideXlab platform.
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structural characteristics and mechanical properties of Aluminium Oxide thin films prepared by off plane filtered cathodic vacuum arc system
Surface & Coatings Technology, 2003Co-Authors: Z W Zhao, B K Tay, D SheejaAbstract:Transparent and smooth alumina thin films have been deposited on Si (1 0 0) and quartz substrates at low temperature by an off-plane double bend filtered cathodic vacuum arc (FCVA) system, which is slightly different from traditional vacuum arc system. The films were analysed using X-ray diffraction and X-ray photoemission spectroscopy to investigate the crystalline and chemical characteristics of these thin films. The films displayed a very smooth surface morphology, which were verified from AFM and SEM. The compressive stress, hardness and Young's modulus of Aluminium Oxide thin films deposited under varying oxygen partial pressure were investigated, and compared with that by other technologies. Friction coefficient of stoichiometric film against steel and DLC balls were analysed by tribometer (pin-on-disk), respectively. The deposited stoichiometric Aluminium Oxide thin films possess good optical properties. The results show that the alumina thin films prepared by FCVA technology have potential applications as wear-resistance coatings and optical coatings.
N A Rahim - One of the best experts on this subject based on the ideXlab platform.
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energy and exergy analysis of a flat plate solar collector using different sizes of Aluminium Oxide based nanofluid
Journal of Cleaner Production, 2016Co-Authors: Zafar Said, R Saidur, N A RahimAbstract:Abstract Growing dependence of industry and technology on fossil energy and increasing population encounters all countries with challenge of energy for future. Therefore, investigation about renewable energies, particularly solar energy is considered. The use of nanofluids in solar collectors offers better performance, as they are very efficient in transporting heat even under small temperature difference. The effect of Aluminium Oxide (Al 2 O 3 )–water nanofluid, as working fluid, is used to evaluate the thermal efficiency of a flat plate solar collector, experimentally. A volume fraction of 0.1% for size of (13 nm and 20 nm) nanoparticles, respectively was used for this study. The mass flow rates of the nanofluid varied from 0.5 to 1.5 kg/min. Experiments were carried out using a stable nanofluid. The stability of nanofluid was obtained by controlling the pH of the solution. An ASHRAE Standard 93-2010 (R2014) was used to analyze efficiency of the solar collector. The results reflect the contribution and significance of each of these parameters to the collector overall energetic and exergetic efficiencies. Two different sizes of Al 2 O 3 –water nanofluid 13 nm and 20 nm are examined, and results show that 13 nm Al 2 O 3 nanofluid shows higher thermal conductivity enhancement and efficiency, compared to that of 20 nm Al 2 O 3 nanofluid and water. Al 2 O 3 –H 2 O (13 nm) nanofluid with 0.1% volume fraction and at a flow rate of 1.5 kg/min showed the highest energy efficiency of about 73.7%, compared to Al 2 O 3 –H 2 O (20 nm) nanofluid, which showed an energy efficiency of 70.7%. Critical point of Al 2 O 3 –water nanofluid is also presented, which has not be reported in literature according to author's knowledge, which also shows the novelty of this work.
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energy and exergy analysis of a flat plate solar collector using different sizes of Aluminium Oxide based nanofluid
Journal of Cleaner Production, 2016Co-Authors: Zafar Said, R Saidur, N A RahimAbstract:Abstract Growing dependence of industry and technology on fossil energy and increasing population encounters all countries with challenge of energy for future. Therefore, investigation about renewable energies, particularly solar energy is considered. The use of nanofluids in solar collectors offers better performance, as they are very efficient in transporting heat even under small temperature difference. The effect of Aluminium Oxide (Al 2 O 3 )–water nanofluid, as working fluid, is used to evaluate the thermal efficiency of a flat plate solar collector, experimentally. A volume fraction of 0.1% for size of (13 nm and 20 nm) nanoparticles, respectively was used for this study. The mass flow rates of the nanofluid varied from 0.5 to 1.5 kg/min. Experiments were carried out using a stable nanofluid. The stability of nanofluid was obtained by controlling the pH of the solution. An ASHRAE Standard 93-2010 (R2014) was used to analyze efficiency of the solar collector. The results reflect the contribution and significance of each of these parameters to the collector overall energetic and exergetic efficiencies. Two different sizes of Al 2 O 3 –water nanofluid 13 nm and 20 nm are examined, and results show that 13 nm Al 2 O 3 nanofluid shows higher thermal conductivity enhancement and efficiency, compared to that of 20 nm Al 2 O 3 nanofluid and water. Al 2 O 3 –H 2 O (13 nm) nanofluid with 0.1% volume fraction and at a flow rate of 1.5 kg/min showed the highest energy efficiency of about 73.7%, compared to Al 2 O 3 –H 2 O (20 nm) nanofluid, which showed an energy efficiency of 70.7%. Critical point of Al 2 O 3 –water nanofluid is also presented, which has not be reported in literature according to author's knowledge, which also shows the novelty of this work.
Z W Zhao - One of the best experts on this subject based on the ideXlab platform.
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optical properties of Aluminium Oxide thin films prepared at room temperature by off plane filtered cathodic vacuum arc system
Thin Solid Films, 2003Co-Authors: Z W Zhao, B K Tay, Daniel H C Chua, Shu Ping Lau, L K CheahAbstract:An off-plane filtered cathodic vacuum arc (FCVA) system has been developed to deposit large area (up to 8 inch) optical coatings with good uniformity controlled by scanning magnetic field system. With this FCVA system, Aluminium Oxide thin films were deposited with high deposition rate (1.5-0.5 nm/s) on Si (100) and quartz substrates at room temperature under different oxygen pressures (1×10−2–3.73×10−2 Pa). The evolution of Al 2p core level and oxygen concentration in the films was studied by XPS spectra. In addition to the good uniformity (±2%) in terms of thickness and smooth surface (RMS: approx. 0.1 nm), the as-grown films were amorphous with low stress (less than 0.5 GPa). The variation of deposition rate with oxygen pressure was investigated. Optical properties, such as film transmittance and optical constants of Aluminium Oxide thin films formed under different oxygen pressures were determined. Film properties demonstrate the potential applications for Aluminium Oxide thin films in optical coatings and for FCVA technology in deposition of metal Oxide optical coatings.
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structural characteristics and mechanical properties of Aluminium Oxide thin films prepared by off plane filtered cathodic vacuum arc system
Surface & Coatings Technology, 2003Co-Authors: Z W Zhao, B K Tay, D SheejaAbstract:Transparent and smooth alumina thin films have been deposited on Si (1 0 0) and quartz substrates at low temperature by an off-plane double bend filtered cathodic vacuum arc (FCVA) system, which is slightly different from traditional vacuum arc system. The films were analysed using X-ray diffraction and X-ray photoemission spectroscopy to investigate the crystalline and chemical characteristics of these thin films. The films displayed a very smooth surface morphology, which were verified from AFM and SEM. The compressive stress, hardness and Young's modulus of Aluminium Oxide thin films deposited under varying oxygen partial pressure were investigated, and compared with that by other technologies. Friction coefficient of stoichiometric film against steel and DLC balls were analysed by tribometer (pin-on-disk), respectively. The deposited stoichiometric Aluminium Oxide thin films possess good optical properties. The results show that the alumina thin films prepared by FCVA technology have potential applications as wear-resistance coatings and optical coatings.
A V Ustinov - One of the best experts on this subject based on the ideXlab platform.
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Aluminium Oxide wires for superconducting high kinetic inductance circuits
Superconductor Science and Technology, 2017Co-Authors: Hannes Rotzinger, Sebastian T Skacel, Marco Pfirrmann, Jan Nicolas Voss, J Munzberg, S Probst, P Bushev, Martin Weides, A V UstinovAbstract:We investigate thin films of conducting Aluminium-Oxide, also known as granular Aluminium, as a material for superconducting high quality, high kinetic inductance circuits. The films are deposited by an optimised reactive DC magnetron sputter process and characterised using microwave measurement techniques at milli-Kelvin temperatures. We show that, by precise control of the reactive sputter conditions, a high room temperature sheet resistance and therefore high kinetic inductance at low temperatures can be obtained. For a coplanar waveguide resonator with 1.5 kΩ sheet resistance and a kinetic inductance fraction close to unity, we measure a quality factor in the order of 700 000 at 20 mK. Furthermore, we observe a sheet resistance reduction by gentle heat treatment in air. This behaviour is exploited to study the kinetic inductance change using the microwave response of a coplanar wave guide resonator. We find the correlation between the kinetic inductance and the sheet resistance to be in good agreement with theoretical expectations.
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Aluminium Oxide wires for superconducting high kinetic inductance circuits
arXiv: Superconductivity, 2014Co-Authors: Hannes Rotzinger, Sebastian T Skacel, Marco Pfirrmann, Jan Nicolas Voss, J Munzberg, S Probst, P Bushev, Martin Weides, A V UstinovAbstract:We investigate thin films of conducting Aluminium-Oxide, also known as granular Aluminium, as a material for superconducting high quality, high kinetic inductance circuits. The films are deposited by an optimised reactive DC magnetron sputter process and characterised using microwave measurement techniques at milli-Kelvin temperatures. We show that, by precise control of the reactive sputter conditions, a high room temperature sheet resistance and therefore high kinetic inductance at low temperatures can be obtained. For a coplanar waveguide resonator with 1.5\,k$\Omega$ sheet resistance and a kinetic inductance fraction close to unity, we measure a quality factor in the order of 700\,000 at 20\,mK. Furthermore, we observe a sheet resistance reduction by gentle heat treatment in air. This behaviour is exploited to study the kinetic inductance change using the microwave response of a coplanar wave guide resonator. We find the correlation between the kinetic inductance and the sheet resistance to be in good agreement with theoretical expectations.