scholarly journals Comparison of ultraviolet light emitting diodes with traditional UV for greywater disinfection

2014 ◽  
Vol 5 (1) ◽  
pp. 17-27 ◽  
Author(s):  
M. J. Crook ◽  
B. Jefferson ◽  
O. Autin ◽  
J. MacAdam ◽  
A. Nocker
Keyword(s):  
Particle Size ◽  
Ultraviolet Light ◽  
Water Reuse ◽  
Light Emitting Diodes ◽  
Microbial Inactivation ◽  
Small Scale ◽  
Light Emitting ◽  
Uv Leds ◽  
The Impact ◽  
Ultraviolet Light Emitting Diodes

The current technological status of ultraviolet light emitting diodes (UV-LEDs) has reached a point where small-scale ultraviolet (UV) water disinfection applications, that is, for greywater reuse appear increasingly promising. This study compares the germicidal and economical aspects of UV-LEDs with traditional UV. Pure cultures and environmental greywater samples were exposed to different radiation doses from both UV sources with the germicidal effect comparative at equivalent doses. The impact of particle size on disinfection efficiency was investigated in two greywater fractions of varying mean particle size. Disinfection efficiency was found to be dependent on particle size with larger particles reducing microbial inactivation for both UV sources. Post-UV blending to detach particle-associated coliforms resulted in higher bacterial counts for both UV sources although to a lesser extent for UV-LEDs suggesting that it might be less affected by the presence of particles than traditional UV sources, possibly due to the UV radiation being emitted by multiple diodes at different angles compared to the traditional UV collimated beam setup. Nevertheless, removal of particles prior to UV disinfection is necessary to meet strict water reuse standards. Although UV-LEDs are currently prohibitively expensive, improvements in performance indicators might make this technology economically competitive within the next few years.

scholarly journals Investigating the Use of Ultraviolet Light Emitting Diodes (UV-LEDs) for the Inactivation of Bacteria in Powdered Food Ingredients

Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 797
Author(s):  
Laura Nyhan ◽  
Milosz Przyjalgowski ◽  
Liam Lewis ◽  
Máire Begley ◽  
Michael Callanan
Keyword(s):  
Ultraviolet Light ◽  
Light Emitting Diodes ◽  
Bacterial Species ◽  
Microbial Inactivation ◽  
Inactivation Kinetics ◽  
Food Ingredients ◽  
Light Emitting ◽  
Uv Lamps ◽  
Uv Leds ◽  
Ultraviolet Light Emitting Diodes

The addition of contaminated powdered spices and seasonings to finished products which do not undergo further processing represents a significant concern for food manufacturers. To reduce the incidence of bacterial contamination, seasoning ingredients should be subjected to a decontamination process. Ultraviolet light emitting diodes (UV-LEDs) have been suggested as an alternative to UV lamps for reducing the microbial load of foods, due to their increasing efficiency, robustness and decreasing cost. In this study, we investigated the efficacy of UV-LED devices for the inactivation of four bacteria (Listeria monocytogenes, Escherichia coli, Bacillus subtilis and Salmonella Typhimurium) on a plastic surface and in four powdered seasoning ingredients (onion powder, garlic powder, cheese and onion powder and chilli powder). Surface inactivation experiments with UV mercury lamps, UVC-LEDs and UVA-LEDs emitting at wavelengths of 254 nm, 270 nm and 365 nm, respectively, revealed that treatment with UVC-LEDs were comparable to, or better than those observed using the mercury lamp. Bacterial reductions in the seasoning powders with UVC-LEDs were less than in the surface inactivation experiments, but significant reductions of 0.75–3 log10 colony forming units (CFU) were obtained following longer (40 s) UVC-LED exposure times. Inactivation kinetics were generally nonlinear, and a comparison of the predictive models highlighted that microbial inactivation was dependent on the combination of powder and microorganism. This study is the first to report on the efficacy of UV-LEDs for the inactivation of several different bacterial species in a variety of powdered ingredients, highlighting the potential of the technology as an alternative to the traditional UV lamps used in the food industry.

scholarly journals 310 nm UV-LEDs attenuate imiquimod-induced psoriasis-like skin lesions in C57BL/6 mice and inhibit IL-22-induced STAT3 expression in HaCaT cells

2020 ◽  
Vol 19 (8) ◽  
pp. 1009-1021
Author(s):  
Tae-Rin Kwon ◽  
Sung-Eun Lee ◽  
Jong Hwan Kim ◽  
You Na Jang ◽  
Su-Young Kim ◽  
...  
Keyword(s):  
Light Source ◽  
Ultraviolet Light ◽  
Light Emitting Diodes ◽  
Skin Lesions ◽  
Hacat Cells ◽  
Light Emitting ◽  
Uv Leds ◽  
Ultraviolet Light Emitting Diodes

Ultraviolet light-emitting diodes (UV-LEDs) are a novel light source for phototherapy.

Development of an Al2O3 filled composite for the bracket of ultraviolet light-emitting diodes (UV-LEDs)

2018 ◽  
Vol 83 ◽  
pp. 356-362 ◽  
Author(s):  
Lei Zhang ◽  
Yiting Zheng ◽  
Jiale Mao ◽  
Shuang Wang ◽  
Ruotian Fu ◽  
...  
Keyword(s):  
Ultraviolet Light ◽  
Light Emitting Diodes ◽  
Light Emitting ◽  
Uv Leds ◽  
Ultraviolet Light Emitting Diodes ◽  
Filled Composite

ACCURATE MEASUREMENT OF ULTRAVIOLET LIGHT-EMITTING DIODES

2021 ◽  
Author(s):  
C. Yuqin Zong ◽  
Cameron Miller
Keyword(s):  
Ultraviolet Light ◽  
Light Emitting Diodes ◽  
Luminous Flux ◽  
Junction Temperature ◽  
Integrating Sphere ◽  
Light Emitting ◽  
Type D ◽  
Uv Led ◽  
Uv Leds ◽  
Ultraviolet Light Emitting Diodes

We have developed a new calibration capability for 200 nm to 400 nm ultraviolet light-emitting diodes (UV LEDs) using a Type D gonio-spectroradiometer. The recently-introduced mean differential continuous pulse (M-DCP) method is used to overcome the measurement difficulty associated with the initial forward voltage, VF, anomaly of a UV LED, which makes it impossible to use VF to infer junction temperature, TJ, during pulsed operation. The new measurement facility was validated indirectly by comparing the measured total luminous flux of a white LED with that measured using the NIST’s 2.5 m absolute integrating sphere. The expanded calibration uncertainty for the total radiant flux is approximately 2 % to 3 % (k = 2) depending the wavelength of the UV LED.

Ultraviolet light emitting diodes using non-polar A-plane AlGaN multiple quantum wells

2006 ◽  
Vol 955 ◽  
Author(s):  
Ramya Chandrasekaran ◽  
Anirban Bhattacharyya ◽  
Ryan France ◽  
Christos Thomidis ◽  
Adrian Williams ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Ultraviolet Light ◽  
Light Emitting Diodes ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Light Emitting ◽  
Current Voltage ◽  
Uv Leds ◽  
Ultraviolet Light Emitting Diodes ◽  
Electro Luminescence

ABSTRACTIn this paper, we report the growth and fabrication of non-polar A-plane AlGaN multiple quantum well based ultraviolet light emitting diodes (UV-LEDs). The LEDs were grown on R-plane sapphire substrates using molecular beam epitaxy (MBE). The Current-voltage characteristics of the fabricated devices demonstrated rectifying behavior with a series resistance of 38 ohms. An electro-luminescence emission at 338 nm was obtained.

Sign in / Sign up

Export Citation Format

Share Document