ABSTRACT
Thermal Cycler is the main part of the Polymerase Chain Reaction (PCR), which becoming a gold standard for Covid-19 diagnosis. The virus multiplication in an order to a detectable concentration is done by placing the virus solution at a deterministic temperature cycle. The solution is placed in a small tube inserted in a temperature block. Temperature distribution of the thermal block is important to make all the tube with sample treated at the same at desired target temperature. Study on the thermal block made of aluminium 7075 was simulated using fluid dynamic finite element method. Heating and colling to the target temperature was done by providing heat source and heat absorber. The temperature distribution on the surface was mapped. The temperature gradient perpendicular to the heat source was calculated. Assuming the environment of the thermal block was still air, the heating and cooling speed at given heat source and heat removal were calculated using the model. The temperature gradient from the top surface to the bottom surface is less than 2.5?. The temperature difference among point at the surface is less than 0.1?. © Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence.
ABSTRACT
Ultraviolet Light Emitting Diode (UV LED) is becoming popular, especially during the Covid-19 pandemic. UV LED has a specific wavelength with relatively narrow bandwidth, especially the one that has a shorter wavelength. On the other hand, UV LED has advantages in its low power consumption, compact size, and longer lifetime. This work shows that a wider bandwidth can be elicited by combining multiple UV LED sources. We have measured several low-cost UV LED, which is used as a germicidal lamp using a portable spectrometer that can detect a wavelength from 200 nm to 850 nm. The combined UV LED spectrum light ranges from 254 nm UVC to 400 nm UVA. The light spectrum produced by the LED shows a form of the Gaussian distribution model. Some LEDs have a peak wavelength at UVC around 270nm, and LEDs have a peak wavelength around 400nm at UVA. We can conclude that the low-cost UV LED can be used as a light source for portable or field spectrometers for specific wavelength.