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34 results on '"Sivan, Vijay"'

2. Highly-Efficient Selective Metamaterial Absorber for High-Temperature Solar Thermal Energy Harvesting

Author

Wang, Hao, Sivan, Vijay Prasad, Mitchell, Arnan, Rosengarten, Gary, Phelan, Patrick, and Wang, Liping

Subjects
Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics, Physics - Optics
Abstract

In this work, a metamaterial selective solar absorber made of nanostructured titanium gratings deposited on an ultrathin MgF2 spacer and a tungsten ground film is proposed and experimentally demonstrated. Normal absorptance of the fabricated solar absorber is characterized to be higher than 90% in the UV, visible and, near infrared (IR) regime, while the mid-IR emittance is around 20%. The high broadband absorption in the solar spectrum is realized by the excitation of surface plasmon and magnetic polariton resonances, while the low mid-IR emittance is due to the highly reflective nature of the metallic components. Further directional and polarized reflectance measurements show wide-angle and polarization-insensitive high absorption within solar spectrum. Temperature-dependent spectroscopic characterization indicates that the optical properties barely change at elevated temperatures up to 350{\deg}C. The solar-to-heat conversion efficiency with the fabricated metamaterial solar absorber is predicted to be 78% at 100{\deg}C without optical concentration or 80% at 400{\deg}C with 25 suns, and could be further improved with better fabrication processes and geometric optimization during metamaterial design. The strong spectral selectivity, favorable diffuse-like behavior, and excellent thermal stability make the metamaterial selective absorber promising for significantly enhancing solar thermal energy harvesting in various system at mid to high temperatures., Comment: 22 pages, 6 figures

Published
2014
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3. Ultraviolet laser induced domain inversion on chromium coated lithium niobate crystals

Author

Boes, Andreas, Yudistira, Didit, Crasto, Tristan, Steigerwald, Hendrik, Sivan, Vijay, Limboeck, Thorsten, Friend, James, Mailis, Sakellaris, Soergel, Elisabeth, and Mitchell, Arnan

Subjects
Optical Physics, Nanotechnology
Abstract

Direct UV laser writing on chromium coated lithium niobate (LiNbO3) crystals is found to produce spontaneous domain inversion associated with the exposed UV laser tracks. Experimental evidence suggests that this effect is attributed to local out-diffusion of oxygen, reducing the LiNbO3 crystal surface due to the presence of chromium. The thin chromium film becomes hot and reactive after absorbing the UV laser radiation thus acting as an oxygen getter. This very efficient process enables the inversion of domains at lower intensities as compared to other direct laser based poling methods practically eliminating the deleterious surface damage induced by the direct absorption of the UV laser radiation by the crystal. Furthermore, the versatility of this domain fabrication method, is demonstrated by the production of inverted domain structures on Z-, Y- and 128°YX-cut substrates. © 2014 Optical Society of America.

Published
2014

4. Liquid metal enabled pump

Author

Tang, Shi-Yang, Khoshmanesh, Khashayar, Sivan, Vijay, Petersen, Phred, O'Mullane, Anthony P., Abbott, Derek, Mitchell, Arnan, and Kalantar-zadeh, Kourosh

Published
2014

12. Liquid Metal/Metal Oxide Frameworks with Incorporated Ga2O3 for Photocatalysis

Author

Zhang, Wei, primary, Naidu, Boddu S., additional, Ou, Jian Zhen, additional, O’Mullane, Anthony P., additional, Chrimes, Adam F., additional, Carey, Benjamin J., additional, Wang, Yichao, additional, Tang, Shi-Yang, additional, Sivan, Vijay, additional, Mitchell, Arnan, additional, Bhargava, Suresh K., additional, and Kalantar-zadeh, Kourosh, additional

Published
2015
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15. Liquid Metal Actuator for Inducing Chaotic Advection

Author

Tang, Shi-Yang, primary, Sivan, Vijay, additional, Petersen, Phred, additional, Zhang, Wei, additional, Morrison, Paul D., additional, Kalantar-zadeh, Kourosh, additional, Mitchell, Arnan, additional, and Khoshmanesh, Khashayar, additional

Published
2014
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16. Liquid Metal/Metal Oxide Frameworks

Author

Zhang, Wei, primary, Ou, Jian Zhen, additional, Tang, Shi-Yang, additional, Sivan, Vijay, additional, Yao, David D., additional, Latham, Kay, additional, Khoshmanesh, Khashayar, additional, Mitchell, Arnan, additional, O'Mullane, Anthony P., additional, and Kalantar-zadeh, Kourosh, additional

Published
2014
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20. Electrochemically induced actuation of liquid metal marbles

Author

Tang, Shi-Yang, primary, Sivan, Vijay, additional, Khoshmanesh, Khashayar, additional, O'Mullane, Anthony P., additional, Tang, Xinke, additional, Gol, Berrak, additional, Eshtiaghi, Nicky, additional, Lieder, Felix, additional, Petersen, Phred, additional, Mitchell, Arnan, additional, and Kalantar-zadeh, Kourosh, additional

Published
2013
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21. Liquid Metal Marbles

Author

Sivan, Vijay, primary, Tang, Shi‐Yang, additional, O'Mullane, Anthony P., additional, Petersen, Phred, additional, Eshtiaghi, Nicky, additional, Kalantar‐zadeh, Kourosh, additional, and Mitchell, Arnan, additional

Published
2012
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29. Liquid metal enabled pump.

Author

Shi-Yang Tang, Khoshmanesh, Khashayar, Sivan, Vijay, Petersen, Phred, O'Mullane, Anthony P., Abbott, Derek, Mitchell, Arnan, and Kalantar-zadeh, Kourosh

Subjects
LIQUID metals, NANOELECTROMECHANICAL systems, FABRICATION (Manufacturing), MANUFACTURING processes, METALLIC surfaces, MICROFLUIDICS
Abstract

Small-scale pumps will be the heartbeat of many future micro/ nanoscale platforms. However, the integration of small-scale pumps is presently hampered by limited flow rate with respect to the input power, and their rather complicated fabrication processes. These issues arise as many conventional pumping effects require intricate moving elements. Here, we demonstrate a system that we call the liquid metal enabled pump, for driving a range of liquids without mechanical moving parts, upon the application of modest electric field. This pump incorporates a droplet of liquid metal, which induces liquid flow at high flow rates, yet with exceptionally low power consumption by electrowetting/deelectrowetting at the metal surface. We present theory explaining this pumping mechanism and show that the operation is fundamentally different from other existing pumps. The presented liquid metal enabled pump is both efficient and simple, and thus has the potential to fundamentally advance the field of microfluidics. [ABSTRACT FROM AUTHOR]

Published
2014
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30. Liquid Metal/Metal Oxide Frameworks with Incorporated Ga2O3for Photocatalysis

Author

Zhang, Wei, Naidu, Boddu S., Ou, Jian Zhen, O’Mullane, Anthony P., Chrimes, Adam F., Carey, Benjamin J., Wang, Yichao, Tang, Shi-Yang, Sivan, Vijay, Mitchell, Arnan, Bhargava, Suresh K., and Kalantar-zadeh, Kourosh

Abstract

Solvothermally synthesized Ga2O3nanoparticles are incorporated into liquid metal/metal oxide (LM/MO) frameworks in order to form enhanced photocatalytic systems. The LM/MO frameworks, both with and without incorporated Ga2O3nanoparticles, show photocatalytic activity due to a plasmonic effect where performance is related to the loading of Ga2O3nanoparticles. Optimum photocatalytic efficiency is obtained with 1 wt % incorporation of Ga2O3nanoparticles. This can be attributed to the sub-bandgap states of LM/MO frameworks, contributing to pseudo-ohmic contacts which reduce the free carrier injection barrier to Ga2O3.

Published
2015
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31. Liquid Metal Marbles.

Author

Sivan, Vijay, Tang, Shi‐Yang, O'Mullane, Anthony P., Petersen, Phred, Eshtiaghi, Nicky, Kalantar‐zadeh, Kourosh, and Mitchell, Arnan

Abstract

Liquid metal marbles that are droplets of liquid metal encapsulated by micro- or nanoparticles are introduced. Droplets of galinstan liquid metal are coated with insulators (including Teflon and silica) and semiconductors (including WO3, TiO2, MoO3, In2O3 and carbon nanotubes) by rolling over a powder bed and also by submerging in colloidal suspensions. It is shown that these marbles can be split and merged, can be suspended on water, and are even stable when moving under the force of gravity and impacting a flat solid surface. Furthermore, the marble coating can operate as an active electronic junction and the nanomaterial coated liquid metal marble can act as a highly sensitive electrochemical based heavy metal ion sensor. This new element thus represents a significant platform for the advancement of research into soft electronics. [ABSTRACT FROM AUTHOR]

Published
2013
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33. Investigation of the physical origins of etching LiNbO3 during Ti in-diffusion.

Author

Sivan, Vijay, Holland, Anthony, O'Mullane, Anthony P., and Mitchell, Arnan

Subjects
*ATMOSPHERIC water vapor, *LITHIUM niobate, *IONS, *DIFFUSION, *SEMICONDUCTOR doping
Abstract

We investigate the physical origins of etching observed during Ti diffusion. The relationship between observed etch depth and water vapor content in the annealing environment is quantified. The dynamics of the etching process are also identified. It is discovered that water vapor content is essential for etching and that there is a characteristic delay before etching is observed. From these observations we can conclude that the process is electrochemical in nature with ionic defects diffusing into the Ti strip from the lithium niobate and these defects catalyzing the dissociation of water into reactive ions. [ABSTRACT FROM AUTHOR]

Published
2010
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