ABSTRACT
About 80% of the patients recovering from COVID-19 have inflammation symptoms, like brain fog, myopathy, myalgia, muscle weariness, headache, mental tiredness, asthenia, adynamia, dizziness, tinnitus, hearing loss, telogenic effluvium and mood disturbances. Here, we demonstrate how transcranial and systemic photobiomodulation using near-infrared LEDs emitting 850 nm wavelength light enhanced cognition and reduced pain. Participants were separated into transcranial photobiomodulation with near-infrared LEDs (850 nm, 10W, 10 minutes), photobiomodulation with a punctual cutaneous application (850nm, 10W, 10-40 minutes), and both treatments. All patients underwent 10-day treatments at least. © 2023 SPIE.
ABSTRACT
The temperature-dependent external quantum efficiency (EQE) droops of 265 nm, 275 nm, 280 nm, and 285 nm AlGaN-based ultraviolet-c light-emitting diodes (UVC-LEDs) differed in Al contents have been comprehensively investigated. The modifiedABCmodel (R = An+Bn2+Cn3) with the current-leakage related term,f(n)= Dn4, has been employed to analyze the recombination mechanisms in these UVC-LED samples. Experimental results reveal that, at relatively low electrical-current levels, the contribution of Shockley-Read-Hall (SRH) recombination exceeds those of the Auger recombination and carrier leakage. At relatively high electrical-current levels, the Auger recombination and carrier leakage jointly dominate the EQE droop phenomenon. Moreover, the inactivation efficiencies of 222 nm excimer lamp, 254 nm portable Mercury lamp, 265 nm, 280 nm, and 285 nm UVC-LED arrays in the inactivation ofEscherichia colihave been experimentally investigated, which could provide a technical reference for fighting against the new COVID-19.
ABSTRACT
UV-LED irradiation has attracted attention in water and wastewater disinfection applications. However, no studies have quantitatively investigated the impact of light intensity on the UV dosage for the same magnitude of disinfection. This study presents a powerful 280 nm UV-LED photoreactor with adjustable light intensity to disinfect municipal wastewater contaminated with E. coli, SARS-CoV-2 genetic materials and others. The disinfection performance of the 280 nm LED was also compared with 405 nm visible light LEDs, in terms of inactivating E. coli and total coliforms, as well as reducing cATP activities. The results showed that the UV dose needed per log reduction of E. coli and total coliforms, as well as cATP, could be decreased by increasing the light intensity within the investigated range (0–9640 µW/cm2). Higher energy consumption is needed for microbial disinfection using the 405 nm LED when compared to 280 nm LED. The signal of SARS-CoV-2 genetic material in wastewater and the SARS-CoV-2 spike protein in pure water decreased upon 280 nm UV irradiation. © 2023 by the authors.
ABSTRACT
Given the current coronavirus (COVID-19) situation around the world, we may have to face a long-term battle with coronavirus. It is necessary to prepare and stay resilient with some other techniques to improve air quality in buildings, especially in clinics and hospitals. In this paper, we have developed Ultraviolet-C (UVC) light-emitting diode (LED) modules which can be implemented in air ducts in heating, ventilation, and air conditioning system for airborne disinfection. An LED module is designed with LED panels as the basic unit so that it is easy to scale up to accommodate for air ducts with different sizes. Both experiments and simulations are carried out to study its disinfection performance. The results show that more than 76% and 85% of the pathogen can be inactivated within 60 and 90 min, respectively, in a meeting room with a volume of 107 m3 by using one LED module. Simulations for two LED modules show that the disinfection efficacy is more than two times compared to that of one LED module. In addition to the pathogen used in the experiments, the disinfection performance of the LED module for inactivation of SARS-CoV-2 virus based on the literature is investigated numerically. It shows that more than 99.70% of pathogens receive UV dose larger than 4.47 J/m2, leading to an almost 89.10% disinfection rate for SARS-CoV-2 virus within one hour using the two LED modules in the same meeting room. © 2023 Author(s).
ABSTRACT
Existing indoor closed ultraviolet-C (UVC) air purifiers (UVC in a box) have faced technological challenges during the COVID-19 breakout, owing to demands of low energy consumption, high flow rates, and high kill rates at the same time. A new conceptual design of a novel UVC-LED (light-emitting diode) air purifier for a low-cost solution to mitigate airborne diseases is proposed. The concept focuses on performance and robustness. It contains a dust-filter assembly, an innovative UVC chamber, and a fan. The low-cost dust filter aims to suppress dust accumulation in the UVC chamber to ensure durability and is conceptually shown to be easily replaced while mitigating any possible contamination. The chamber includes novel turbulence-generating grids and a novel LED arrangement. The turbulent generator promotes air mixing, while the LEDs inactivate the pathogens at a high flow rate and sufficient kill rate. The conceptual design is portable and can fit into ventilation ducts. Computational fluid dynamics and UVC ray methods were used for analysis. The design produces a kill rate above 97% for COVID and tuberculosis and above 92% for influenza A at a flow rate of 100 L/s and power consumption of less than 300 W. An analysis of the dust-filter performance yields the irradiation and flow fields.
ABSTRACT
The nutritional quality and biomass of various sprouts can be enhanced by Zn and red-blue light, especially the Brassica sprouts. However, the combined effects of this two on sprouts are rarely reported. In this study, different Zn concentrations (0, 1.74, 3.48, 10.43 and 17.39 mM) were combined with two ratios of red-blue light-emitting diodes (LEDs) (R: B = 1:2, 1R2B;R: B = 2:1, 2R1B, at 70 μmol m−2 s−1 PPFD, 14 h/10 h, light/dark) to investigate their mutual effects on the growth, mineral elements, and nutritional quality in flowering Chinese cabbage sprouts (FCCS). Fresh weight, dry weight, contents of organic Zn, soluble sugar, vitamin C, total flavonoids, total polyphenol, FRAP (ferric ion-reducing antioxidant power) and DPPH (radical inhibition percentage of 1,1-diphenyl-2-picrylhydrazyl) were significantly increased by Zn supplement (10.43 and 17.39 mM) and 2R1B, while hypocotyl length and moisture content were decreased remarkably by Zn supplement. Total glucosinolates contents in the sprouts increased dramatically under 2R1B compared with 1R2B, while photosynthetic pigments contents decreased. Heat map and principal component analysis showed that 2R1B + 17.39 mM Zn was the optimal treatment for the accumulation of biomass and health-promoting compound in FCCS, suggesting that a suitable combination of light quality and Zn supplement might be beneficial to zinc-biofortified FCCS production.
ABSTRACT
In the present scenario like COVID-19 pandemic, to maintain physical distance, the gait-based biometric is a must. Human gait identification is a very difficult process, but it is a suitable distance biometric that also gives good results at low resolution conditions even with face features that are not clear. This study describes the construction of a smart carpet that measures ground response force (GRF) and spatio-temporal gait parameters (STGP) using a polymer optical fiber sensor (POFS). The suggested carpet contains two light detection units for acquiring signals. Each unit obtains response from 10 nearby sensors. There are 20 intensity deviation sensors on a fiber. Light-emitting diodes (LED) are triggered successively, using the multiplexing approach that is being employed. Multiplexing is dependent on coupling among the LED and POFS sections. Results of walking experiments performed on the smart carpet suggested that certain parameters, including step length, stride length, cadence, and stance time, might be used to estimate the GRF and STGP. The results enable the detection of gait, including the swing phase, stance, stance length, and double supporting periods. The suggested carpet is dependable, reasonably priced equipment for gait acquisition in a variety of applications. Using the sensor data, gait recognition is performed using genetic algorithm (GA) and particle swarm optimization (PSO) technique. GA- and PSO-based gait template analyses are performed to extract the features with respect to the gait signals obtained from polymer optical gait sensors (POGS). The techniques used for classification of the obtained signals are random forest (RF) and support vector machine (SVM). The accuracy, sensitivity, and specificity results are obtained using SVM classifier and RF classifier. The results obtained using both classifiers are compared. © 2023 Mamidipaka Hema et al.
ABSTRACT
AlGaN-based deep-ultraviolet light-emitting diodes (DUV LEDs) are widely used in sterilization, sensing, water purification, medical treatment, non-line of sight (NLOS) communication and many other fields. Especially it has been reported that the global novel coronavirus (COVID-19) can be effectively inactivated by the DUV light with a wavelength below 280 nm (UVC) within a few seconds, which has also attracted great attention. However, the external quantum efficiency (EQE) of UVC LED is still at a low level, generally not more than 10%. As an important component of EQE, internal quantum efficiency (IQE) plays a crucial role in realizing high-performance DUV-LED. In order to improve the IQE of AlGaN-based DUV-LED, this work adopts an electron blocking layer (EBL) structure based on InAlGaN/AlGaN superlattice. The results show that the superlattice EBL structure can effectively improve the IQE compared with the traditional single-layer and double-layer EBL structure for the DUV-LED. On this basis, the optimization method based on JAYA intelligent algorithm for LED structure design is proposed in this work. Using the proposed design method, the InAlGaN/AlGaN superlattice EBL structure is further optimized to maximize the LED' s IQE. It is demonstrated that the optimized superlattice EBL structure is beneficial to not only the suppression of electron leakage but also the improvement of hole injection, leading to the increase of carrier recombination in the active region. As a result, the IQE of the DUV-LED at 200 mA injection current is 41.2% higher than that of the single-layer EBL structure. In addition, the optimized structure reduces IQE at high current from 25% to 4%. The optimization method based on intelligent algorithm can break through the limitation of the current LED structure design and provide a new method to improve the efficiency of AlGaN-based DUV-LED. © 2023 Chinese Physical Society.
ABSTRACT
During the current COVID-19 epidemic, everyone needs to take measures, which include wearing a mask, keeping their distance, washing their hands, and avoiding touching anything unless it is absolutely necessary. They typically have a key housing and a key saddle to open ordinary doors. The body temperature sensor-equipped automatic door control system is a prototype designed to stop the spread of COVID-19, which is disseminated through droplets attached to traditional doorknobs, by minimising direct physical contact. In this paper, a temperature controlled door access system using Lab view and arduino is is proposed. LM35 connected to arduino is used for sensing the temperature. The software simulation of the system is done in Lab view, which is then interfaced with Arduino Uno. Further, the system consist of a relay and an LED to indicate whether the door access is granted or not. If a person's body temperature is detected as a value within the normal body temperature range, then LED light appears and relay is activated. This results in opening of the door lock attached with the relay. If a person's body temperature is sensed as a value greater than the normal body temperature range, then LED remains OFF. The system is designed to be placed outside institutions and malls where a person is allowed inside only if his/her body temperature is normal. © 2022 IEEE.
ABSTRACT
Covid-19 is an extremely communicable disease. It becomes extremely hard to control once it begins to spread. One of the most important and effective steps to break the chain and keep healthy people from getting infected is social isolation/distancing. When an infected person comes into contact with a healthy person, that person becomes infected as well, and the chain reaction continues. To curb this, COVID alert system using geo-fencing is developed. This system uses a GPS module to create a Geo Fence around the infected area and the healthy area. The live/current GPS location/coordinate is compared with the hotspot co-ordinates. The GSM module with Sim800L will send an alert to healthy people when they come into contact with virus-infected areas. The device comes with a GPS, GSM module with Sim800L and an OLED which displays the alert message. The device can be fit into any public or private transport, so that the healthy person will be prevented from entering the hotspot zones unnecessarily, thereby blocking the virus spread. © 2022 IEEE.
ABSTRACT
In connection with the COVID-19 pandemic, there is an urgent need for disinfecting devices that can be used both indoors and in transport. Currently, the most common of these devices are ultraviolet (UV) germicidal lamps. However, they have significant disadvantages, such as short service life, presence of mercury, lack of flexible control, large dimensions, etc. The paper analyzes the sources of UV radiation to find an alternative to UV lamps. Although these elements currently have low efficiency and high cost, etc., it is proposed to use UVC LEDs as a UV source. Due to the COVID-19 pandemic and the general interest in the fight against viruses, as well as the ban on the use of mercury, investments have been attracted in the development of UVC LEDs, which will make them competitive in the future compared to germicidal lamps both in cost and efficiency. The paper presents a disinfection device developed on the basis of UVC LEDs. The principle of operation is described;the control system, the drawing, and the design of the UVC LED-based disinfection device are presented. Due to the described limitations of UVC LEDs, this design can be used for disinfection of small surface areas where frequent on/off switching is required and high power is not required.
ABSTRACT
The artificial lighting condition in which humans are exposed have been proven as a harmful factor on their well-being, which is regulated mainly by circadian rhythm. Especially since the COVID-19 pandemic, where external factors forced the society to adapt into new standards when it comes to their jobs and regular activities, lockdowns and work-from-home made most people start spending a portion of their life exposed to artificial sources of light. Technological advances have made lights more efficient and improved their intensity. Light-emitting diodes (LEDs), for example, generally produce high-intensity bluish tone light, which may affect the circadian rhythm. However, it is possible to create lighting systems able to vary the intensity and correlated color temperature (CCT) of the lighting. This work proposes a lighting system that allows adjusting the intensity and CCT of light via remote control on a smartphone application synchronized with time, following a pattern that aims avoid the undesirable artificial lighting effects on circadian rhythm. Using two LED arrays containing 10 LEDs each, suitable results were reached, presenting maximum difference of 3.35 % for CCT and 5.57 % for luminous flux in comparison with reference values.
ABSTRACT
During the period of COVID-19, it is still inevitable for people to contact with each other based on the consideration of economic development. Therefore, the health management measures for staying in the hotel have become an important part of epidemic prevention. As we all know, ultraviolet (UV) light is an effective disinfection and sterilization method, which has been widely used in many applications. In this paper, a hotel anti-epidemic management system is proposed to disinfect the used rooms by using UV LEDs through WiFi communication with the front desk computer, and therefore it can protect quests from virus infection. © 2022 IEEE.
ABSTRACT
In this study, we found that the current droop (J-droop) in AlGaN-based UVB light-emitting diodes was more obvious at higher temperatures, despite both the main and parasitic peaks undergoing monotonic decreases in their intensity upon an increase in the temperature. The slower temperature droop (T-droop) did not occur when the forward current was increased to temperatures greater than 298 K. After an aging time of 6000 h, the emission wavelengths did not undergo any obvious changes, while the intensity of the parasitic peak barely changed. Thus, the degradation in the light output power during long-term operation was not obviously correlated to the existence of the parasitic peak.
ABSTRACT
Legionella pneumophila (L. pneumophila) is the causative agent of Legionnaires’ disease and Pontiac fever, collectively known as legionellosis. L. pneumophila infection occurs through inhalation of contaminated aerosols from water systems in workplaces and institutions. The development of disinfectants that can eliminate L. pneumophila in such water systems without evacuating people is needed to prevent the spread of L. pneumophila. Photocatalysts are attractive disinfectants that do not harm human health. In particular, the TiO2 photocatalyst kills L. pneumophila under various conditions, but its mode of action is unknown. Here, we confirmed the high performance of TiO2 photocatalyst containing PtO2 via the degradation of methylene blue (half-value period: 19.2 min) and bactericidal activity against Escherichia coli (half-value period: 15.1 min) in water. Using transmission electron microscopy, we demonstrate that the disinfection of L. pneumophila (half-value period: 6.7 min) by TiO2 photocatalyst in water is accompanied by remarkable cellular membrane and internal damage to L. pneumophila. Assays with limulus amebocyte lysate and silver staining showed the release of endotoxin from L. pneumophila due to membrane damage and photocatalytic degradation of this endotoxin. This is the first study to demonstrate the disinfection mechanisms of TiO2 photocatalyst, namely, via morphological changes and membrane damage of L. pneumophila. Our results suggest that TiO2 photocatalyst might be effective in controlling the spread of L. pneumophila.
ABSTRACT
Currently the health system continues to fight against the pandemic caused by SARS-CoV2 because this virus has not yet disappeared and there are still outbreaks of infections in several places, this generated in people an indecision of what it can generate later since this virus generated a change in the world. Being a contagious and fast-spreading virus, WHO called on all governments to take appropriate measures to stop the spread of COVID-19 as there were many infected. Given this, there are people who need the care of a doctor because they suffer from a disease and that this implies the extraction of blood for a deep analysis or to place an intravenous injection in the patient's forearm, but in many cases the distribution of the veins can not be visualized and this hinders the work of the doctor. In view of this problem, in this article an automatic vascular detection system was carried out for the part of the forearm of patients and to be able to visualize the subcutaneous vein so that the doctor has access quickly and help the patient in an emergency. Through the development of the system, it was observed that it works in the best way, since in its development a 97.69% efficiency was obtained by showing the binary image where the distribution of the veins is observed taking 8.74 seconds, being an accepted value so that it can be implemented in several medical centers. © 2022 IEEE.
ABSTRACT
This paper examines and evaluates the long-term electrical energy usage of retrofitting lighting systems with varying degrees of control intelligence. One of the most important components of confirming the appropriateness of the application in practice is the long-term energy measurement of these systems. The data analysis and measurement process are described in this article. An intelligent measurement system was used to collect data on electricity consumption. On the basis of these data, an analysis and comparison of various systems were conducted, and the overall electricity consumption for a certain time period was calculated. Finally, a scenario was created to demonstrate the impact of the COVID-19 pandemic on a retrofitted lighting system with various levels of intelligence. © 2022 IEEE.
ABSTRACT
Food security is one of the key global challenges in this century. In Singapore, our research team has been using novel aeroponic technology to produce fresh vegetables since 1997. Aeroponic systems allow for year-round production of not only tropical, but also sub-tropical and temperate fresh vegetables, by simply cooling the roots suspended in aeroponic systems while the aerial parts grow under tropical ambient environments. It has also been used to investigate the impacts of root-zone CO2 on vegetables by enriching root-zone CO2 while their aerial portions were subjected to constant atmospheric CO2. To compensate for the lack of available land, Singapore also needs to develop a farming system that can increase productivity per unit land area by many-fold. Over the past 10 years, my research team has established a commercially viable LED integrated vertical aeroponic farming system to grow different leafy vegetables under different LED spectra, intensities, and durations in the tropical greenhouse. The results demonstrate that it is possible to increase shoot production and rate of shoot production of leafy vegetables by increasing light intensity and extending the photoperiod under effective LED lighting. Furthermore, temperate vegetable crops such as lettuce were able to acclimate to high light intensity under supplementary LED lights to natural sunlight in the greenhouse. Supplementary LED lightings promote both leaf initiation and expansion with increased photo synthetic pigments, higher Cyt b6f and Rubisco protein contents on a per area basis and thus improve photosynthetic capacity and enhance productivity. Plants sense and respond to changes in their immediate environments (microclimate), manipulating the root zone temperature (RZT) and water supply will impact not only their growth and development but also their nutritional quality. Our on-going research aims to investigate if the nutritional quality of leafy vegetables could be improved under suboptimal RZT and mild water deficit through deficit irrigation. If substantial energy and water savings in urban farming can be achieved without substantial yield penalty but with higher nutritional quality, the amount of water and energy saved can bring substantial benefits to society.
ABSTRACT
This paper reports an improved deep ultraviolet LED (DUV-LED) packaging based on Si Micro-Electro-Mechanical Systems (MEMS) process technology. The Si package (Si-PKG) consists of a cavity formed by Si crystalline anisotropic wet etching and through-silicon vias (TSVs) filled with electroplated Cu. The Si-PKG is hermetically sealed by laser local heating of screen-printed glass frit. This technology allows for the use of a DUV-transparent glass substrate, which has an unmatched coefficient of thermal expansion (CTE). Using a high-density array of TSV capped with AuSn solder bumps, the cooling performance of the DUV-LED has been greatly improved. And the contribution by the Si (111) side reflection of Si-PKG to the total light output was confirmed 13 %. As a result, an optical output of 114 % (50 mW) and a volumetric light power density of 380 % (14 mW/mm3) were recorded compared with the conventional AlN-packaged device. The developed compact low-cost Si-PKG is promising for wider applications of the DUV-LED including the disinfection of the new coronaviruses. © 2022 Elsevier B.V.
ABSTRACT
This project is to intimate start and stop time of a particular session with the help of buzzer. A faculty keep on taking his lecture continuously. If the lecture was interesting and engaging the session will be keep on going. Buzzer is used to intimate when will be the session starts and when it will be going to end. Here timing will be predefined. Next one major challenge in schools and colleges is to take attendance manually. For taking attendance with the help of using fingerprint sensor-R307.Here the fingerprints of each and every individual student were stored in the fingerprint sensor itself. If the student keeps his fingerprint, then the particular student attendance is marked. It will only mark attendance if particular person keeps his unique fingerprint. Due to COVID-19 pandemic, central and state government announced to monitor the body temperature of each and every student on daily basis. For monitoring body temperature with help of using Non-contact temperature sensor-MLX90614. We place the temperature sensor near to the fingerprint sensor. If a student comes and keep his fingerprint his attendance will be marked and then he wants to keep his hand to measure his body temperature. If the body temperature of particular student is high means it will displayed in OLED display. To intimate a particular session to the staff. Sometimes staffs have some other work while doing their work they may forget their session. To intimate the session to the staffs by triggering mail or message to the staff. © 2022 IEEE.