scholarly journals White‐light visible light communications based on multiple photoluminescence of fluorescent acrylic sheets

2021 ◽  
Author(s):  
Seonghyeon Cho ◽  
Yoonji Yoo ◽  
Yeonkyeong Lee ◽  
Changseop Lee ◽  
Hyunchae Chun
Keyword(s):  
Visible Light ◽  
White Light ◽  
Visible Light Communications

scholarly journals Visible Light Communications: 170 Mb/s Using an Artificial Neural Network Equalizer in a Low Bandwidth White Light Configuration

2014 ◽  
Vol 32 (9) ◽  
pp. 1807-1813 ◽  
Author(s):  
Paul Anthony Haigh ◽  
Zabih Ghassemlooy ◽  
Sujan Rajbhandari ◽  
Ioannis Papakonstantinou ◽  
Wasiu Popoola
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Visible Light ◽  
White Light ◽  
Visible Light Communications ◽  
Artificial Neural

Visible Light Driven Degradation of Terephthalic Acid: Optimization of Energy Demand by Light Modulation Techniques

2020 ◽  
Vol 01 ◽  
Author(s):  
Diana Sannino ◽  
Vincenzo Vaiano ◽  
Olga Sacco ◽  
Nicola Morante ◽  
Luca De Guglielmo ◽  
...  
Keyword(s):  
Visible Light ◽  
White Light ◽  
Terephthalic Acid ◽  
Kinetic Constant ◽  
Fixed Bed ◽  
Light Modulation ◽  
Photocatalytic Reactor ◽  
Sinusoidal Modulation ◽  
Photocatalytic System ◽  
Modulation Techniques

Aims: The aim of this work was to investigate the impact of light modulation parameters on the degradation of terephtalic acid, an organic model pollutant, within a heterogeneous photocatalytic system under visible light. For this purpose, a fixed bed photocatalytic reactor, irradiated by white-light LEDs matrix controlled by a system for light dimming, was used. The bed consisted of a nitrogen-doped titania photocatalyst deposited on polystyrene pellets. Background: Wastewater containing TPA can be treated into conventional aerobic biological units. However, the mineralization of TPA is slow and inefficient and its presence influences negatively the biodegradation efficiency because this pollutant inhibits microbial growth. Nowadays innovative technologies named advanced oxidation processes (AOPs), such as heterogeneous photocatalysis with UV and visible light, ozonation, Fenton oxidation have gained popularity for effective organic destruction of TPA from wastewater. The heterogeneous photocatalytic oxidation process of the TPA under visible light is the most advantageous process in terms of both fixed and operating costs. Objective: In this work the successful application of light modulation techniques to degradation of TPA using a photocatalytic system with supported visible active photocatalysts (N-doped TiO2) immobilized on polystyrene pellets was reported. In particular, sinusoidal lighting has been used analyzing the influence of the period of oscillation and the amplitude of the light modulation on the reaction kinetics, in such a way as to minimize the times and energy costs for the process. Methods: To evaluate the influence of light modulation on the efficiency of the TPA removal, a discontinuous system composed by a Recirculating Photocatalytic Fixed Bed Reactor (RPFBR) irradiated by a matrix of white light LEDs was used. The flat geometry of photoreactor guarantees the efficient excitation of photocatalyst. An amount of 250 mL of aqueous solution with initial TPA concentration of 12.5 ppm was applied in the photocatalytic tests lasting 180 min of irradiation fixed or sinusoidal modulated. Results: The results show that the variation of the oscillation period of the sinusoidal modulation has a relevant influence on the photodegradation of TPA and a maximum value of the apparent kinetic constant, 0.0045 min-1 is found when the period of oscillation is 0.24 s. The sinusoidal modulation with optimal amplitude is that with current between 50-200 mA, that shows the highest value of the apparent kinetic constant, equal to 0.0046 min-1. The optimal sinusoidal modulation, as a consequence is with current between 50-200 mA and period of 0.24 s. From the data collected from the tests, it is possible to evaluate the energy cost necessary to obtain the reduction of 90% of the terephthalic acid in 1 m3 of polluted water for each modulation (E E/O ), and compare these values with other tests for TPA degradation reported in the literature. The internal comparison and with the three systems of literature showed the optima sinusoidal modulation of LEDs matrix permits a strong reduction the electrical energy consumption. Conclusion: Photocatalytic tests have demonstrated the improvement of the process energy efficiency using the light modulation technique . A further confirmation of the advantage of light modulation was obtained by comparing the energy costs required for the abatement of 90% of the terephthalic acid in 1m 3 of the photocatalytic system. Finally, a mathematical model for photocatalytic degradation of terephthalic acid within the recirculating fixed bed photocatalytic reactor, irradiated by white-light LEDs was developed.

scholarly journals A Relay-Assisted Vehicular Visible Light Communications Network

2020 ◽  
Author(s):  
Elizabeth Eso ◽  
Petr Pesek ◽  
Petr Chvojka ◽  
Zabih Ghassemlooy ◽  
Stanislav Zvanovec ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Communications ◽  
Communications Network
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