Examinando por Autor "Uppinakudru, Adithya Pai"

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Critical assessment of optical sensor parameters for the measurement of ultraviolet LED lamps
(Elsevier, 2022) Uppinakudru, Adithya Pai; Reynolds, Ken; Stanley, Simon; Pablos, Cristina; Marugán, Javier
Measurement of light output from ultraviolet (UV) light-based devices is critical to understanding the capability of the device. Optical sensors such as radiometers and dosimeters can possess different angular responses and are sensitive to many parameters in the measurement set-up. This work has been designed to quantify the effect of multiple parameters on the measurements obtained from optical sensors to provide inputs for validating measured data for ultraviolet sources. Multiple light sources operating in the ultraviolet range have been measured and a comparison between different sensors is presented. The angular response has been evaluated for each detector and compared with an ideal cosine response. Two of the six sensors studied displayed a near cosine response. A change of angle of acceptance with wavelength was observed for the ThorLabs S120VC and ILT W Optic diffuser. Due to use of artificial heating, the effect of measured intensities on the sensor as a function of temperature was seen to be insignificant but provided an understanding of how temperature of the sensor can influence measured data. Finally, the effect of ambient light and the integration time on the measured data were investigated. The effect of ambient light proved to be significant, when not considered in measurement of low light signals sources while the effect of choosing an ideal integration time has been seen to impact the measurements obtained. A measured difference of 43% was observed between a saturated and unsaturated sensor.
UV LED TECHNOLOGY FOR WATER DISINFECTION: A SPECTRUM OF POSSIBILITIES
(Universidad Rey Juan Carlos, 2023) Uppinakudru, Adithya Pai
Access to clean and safe drinking water is a basic human right, as declared by United Nations General Assembly in 2010 (Resolution 64/292). Maintaining and achieving safe water quality is a crucial factor in promoting public health and economic development. Despite technological progress in certain areas, in the 21st century, approximately 29% of the world’s population (2.1 billion people) lack access to drinking water at home. There exist multiple challenges of water scarcity, pollution, and inadequate infrastructure that require a concerted effort from governments and communities to aid the progress of providing safe drinking water worldwide. Climate change is expected to exacerbate water scarcity in many parts of the world, with some regions facing a 50% reduction in available water by 2050. By investing in water infrastructure, promoting water conservation and implementing effective water treatment methods, we can ensure that everyone has access to this essential resource. Traditionally, various methods have been employed for treating water, such as chlorination, sedimentation, filtration, and coagulation. Since the early 1950s, Ultraviolet (UV) light sources have been used by local and national bodies for water disinfection in the final stages to eliminate pathogenic microorganisms. The use of UV light has been found to reduce the growth of microorganisms by inhibiting their reproduction when the DNA/RNA within the microorganism absorbs radiation. Sunlight is the most commonly available natural source of UV. However, it doesn't provide enough UV radiation for quick and effective disinfection. For this reason, artificial UV sources like mercury lamps, light emitting diodes (LEDs), or plasma lamps have been explored for generating UV wavelengths of interest. It is worth noting that sunlight has been used in disinfection processes in low– and medium– income countries using a process called solar water disinfection (SODIS). The technology of UV LEDs is relatively new, with the first commercial UV LED being available in 2003, and has evolved significantly since its discovery with applications in multiple fields like catalysis, air, and surface disinfection etc. Nevertheless, there are still significant challenges associated with the technology and disinfection process that need to be investigated and resolved. Treatment of drinking water and wastewater using UV sources can be energy–intensive and requires optimization to minimize energy consumption. While it may seem that more input radiation to the water matrix can result in faster and higher disinfection rates, it is essential to balance treatment effectiveness, cost, and energy efficiency...