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The Aharonov-Bohm Effect and Transport Properties in Graphene Nanostructures

Abstract

This paper investigates the possibility to improve the filtering process of flue gas by separation of suspended nanoparticle using dielectrophoresis. The study focuses on the particles having an average radius of about 50-150 nm, that cannot be filtrated by classical techniques but have a harmful effect for environment and human health. The size distribution nanoparticles collected from the flue gas filters of a hazardous waste incinerator plant were evaluated. Based on obtained experimental data and a proposed mathematical model, the concentration distribution of nanoparticle suspended in flue gas inside a microfluidic separation device was analyzed by numerical simulations, using the finite element method. The performances of the device were described in terms of three new specific quantities related to the separation process, namely Recovery, Purity and Separation Efficiency. The simulations could provide the optimal values of control parameters for separation process, and aim to be a useful tool in designing microfluidic devices for separating nanoparticle from combustion gases.

Open access
Optical Modeling and Simulation of Tandem Metal Oxide Solar Cells

. Dameron, D. Chua, Y. S. Lee, G. Teeter, R. G. Gordon, T. Buonassisi. Band Offsets of N-Type Electron-Selective Contacts on Cuprous Oxide (Cu2O) for Photovoltaics, Applied Physics Letters 105 (2014) 263901. [17] T. Minami, Y. Nishi, T. Miyata. High-efficiency Cu2O-based heterojunction solar cells fabricated using a Ga 2 O 3 thin film as n-type layer, Applied Physics Express 6(4) (2013) 044101 [18] Ø. Nordseth, R. Kumar, K. Bergum, L. Fara, I. Chilibon, S. E. Foss, E. Monakhov, B. G. Svensson. Silicon-based tandem solar cells. Boosting the performance using

Open access
The Influence of the Precursor Type and of the Substrate on the SPD Deposited TiO2 Photocatalytic Thin Films

Abstract

Photocatalytic degradation of organic pollutants from wastewater using titanium dioxide is recognized as an efficient process. To be feasible, this process needs to be solar- or visible light -activated, but, due to its wide band gap energy, titanium dioxide can only be activated by ultraviolet radiation. In this paper, thin films of titanium dioxide were deposited by Spray Pyrolysis Deposition using organo-metallic (titanium-iso-propoxide) and inorganic (titanium chloride) precursors, as a first step in optimizing the deposition process of titanium dioxide - carbon composite thin films, active in the visible spectral range. The thin films were characterized to outline the differences when using these two precursor solutions, when deposited on Fluorine doped Tin Oxide-glass, regular glass and microscopic glass, in terms of crystallinity (by using X-ray diffraction), elemental composition (using Energy Dispersive X-ray spectrometry), surface morphology (Scanning Electronic Microscopy and Atomic Force Microscopy). The photocatalytic activity of the titanium dioxide thin films was investigated based on the removal efficiencies of methylene blue from a synthetically prepared wastewater. The samples deposited using the inorganic precursor show higher roughness, and this proves to be the most important factor that influences the phocatalytic processes. After 8 hours of ultraviolet irradiation, methylene blue removal efficiencies up to 36% were observed; the highest removal efficiency was registered using the thin titanium dioxide film obtained using the titanium chloride precursor, deposited on fluorine doped tin oxide glass substrate, due to the titanium dioxide-tin dioxide semiconductor tandem formed at the interface, that limits the electron-hole recombination, thus increasing the photoctalytic performance of the substrate.

Open access