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The use of supplemental light has been proven to be effective in growing plants in controlled environments. These light sources have been proven effective in influencing both, developmental and phytochemical pathways. Among artificial/supplemental lights, light emitting diodes (LEDs) offer several advantages and unique properties. Consequently, the use of this novel technology has gained popularity in indoor plant cultivation. In this review, recent achievements and progress related to the preharvest application of LED technology are discussed, starting from the selection of appropriate LED wavelengths to varying photoperiod to enhance crop growth, yield, and phytochemical concentrations. The review further summarises the recent developments in the use of LED technology for cultivating crops hydroponically and the economic implications of LED usage is briefly discussed. Lastly, the future prospects and research directions are presented. [ABSTRACT FROM AUTHOR]

Antirrhinum majus L. has many applications in genetic studies and the medicinal and ornamental plant industries. However, its seeds have a low germination percentage and speed, and the growth of its seedlings is weak, which has caused many problems for researchers and flower growers. Plant germination, development, and flowering are affected by light quality. Recently, light-emitting diodes (LEDs) have been used for multiple purposes in plant production. Accordingly, the influence of light quality on the germination and growth of snapdragons was assessed in this study. Hence, different light treatments included natural daylight (C), white LED (W), blue LED (B), red LED (R), and a mix of 50% blue and 50% red (BR). Germination indices were investigated for up to 21 days. Morphological and biochemical indices were analyzed in seven-day and 30-day-old seedlings, respectively. According to the results, the positive effects of BR treatment were evident in all germination indices, particularly in the germination speed. Morphological indices such as fresh weight, dry weight, shoot height, and root length were the highest in R and BR. Also, growth indices such as the contents of photosynthesis pigments, total soluble carbohydrates, total soluble protein, and total phenolic increased remarkably under the BR treatment. [ABSTRACT FROM AUTHOR]

Effective disinfection procedures in healthcare facilities are essential to prevent transmission. Chemical disinfectants, hydrogen peroxide vapour (HPV) systems and ultraviolet (UV) light are commonly used methods. An emerging method, violet-blue light at 405 nm, has shown promise for surface disinfection. Its antimicrobial properties are based on producing reactive oxygen species (ROS) that lead to the inactivation of pathogens. Studies have shown significant efficacy in reducing bacterial levels on surfaces and in the air, reducing nosocomial infections. The aim of this study was to evaluate the antimicrobial effectiveness of violet-blue (405 nm) LED lamps on high-contact surfaces in a hospital infection-control laboratory. High-contact surfaces were sampled before and after 7 days of exposure to violet-blue light. In addition, the effect of violet-blue light on MRSA-contaminated surfaces was investigated. Exposure to violet-blue light significantly reduced the number of bacteria, yeasts and moulds on the sampled surfaces. The incubator handle showed a low microbial load and no growth after irradiation. The worktable and sink showed an inconsistent reduction due to shaded areas. In the second experiment, violet-blue light significantly reduced the microbial load of MRSA on surfaces, with a greater reduction on steel surfaces than on plastic surfaces. Violet-blue light at 405 nm has proven to be an effective tool for pathogen inactivation in healthcare settings Violet-blue light shows promise as an additional and integrated tool to reduce microbial contamination in hospital environments but must be used in combination with standard cleaning practices and infection control protocols. Further research is needed to optimise the violet-blue, 405 nm disinfection method. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal Renewable Energy is the property of ECORFAN-Mexico S.C. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• DRLs are designed to be on during the day to increase the visibility of vehicles. • There have been no recent studies evaluating DRLs currently present in the fleet. • DRLs reduce non-night-time multi-vehicle crash involvement by 8.8% • Crash reductions were higher at dawn or dusk and in higher speed zones. • A DRL mandate would likely lead to reductions in the overall crash risk of the fleet. Introduction : Many studies have found that daytime running lights (DRLS) are effective in reducing daytime multi-vehicle crashes. From an Australian perspective, while studies exist using data from other jurisdictions, there has been uncertainty about how effective DRLs would be under Australian environmental conditions, which can differ from other parts of the world. In addition, in recent years DRLs have become a standard feature of many new vehicles. The objective of this work was to utilize Australian crash data to estimate the impact of DRLs on casualty crash risk reflecting the Australian crash population and local conditions. It also aimed to broadly examine the real-world crash-based effectiveness of DRLs currently present in the light vehicle fleet. Method : The study utilized police reported casualty crash data for crashes that occurred during 2010–2017. The analysis used induced exposure methods, which offers the potential to assess the relationship between crash risk and DRL fitment by intrinsically controlling for confounding factors. Results : It was found that DRL fitment can reduce the overall risk of being involved in a non-nighttime multi-vehicle crash where vehicle visibility may be a factor in crash causation by a statistically significant 8.8%. Estimated crash reductions were higher at dawn or dusk and in higher speed zones. Conclusion : Results provide clear evidence that mandating DRLs on all new vehicles would likely lead to reductions in the overall crash risk of the fleet through accelerating fitment through the fleet. Practical Application : DRL fitment can reduce the overall risk of being involved in a non-night-time multi-vehicle crash where vehicle visibility may be a factor in crash causation. Governments should consider a DRL mandate on all new vehicle models, including all variants to accelerate the process of fitment through the fleet. This would likely lead to reductions in the overall crash risk of the fleet. [ABSTRACT FROM AUTHOR]

Electricity supply is fundamental for modern society's existence and development, directly impacting health, safety, education, comfort, and other technological applications. One of the important applications of electric energy is lighting, which allows society to make nights even more productive during the day. With the development of LED technology and a significant increase in luminous efficiency, public lighting has undergone a major transformation and replacement of the technology of High-Intensity Discharge (HID) technology. As it is a switched source, this technology is a type of non-linear load, which raises concerns regarding the impacts of harmonic distortions, which can harm equipment connected to the network and cause power losses. In this way, the present study carried out bibliographic research about the losses of electric energy resulting from the incidence of harmonics in the electrical system through the dissemination of the application of LED technology in the public lighting system, using the materials already prepared and published. In this context, this article aims to research studies on harmonic distortions in the public lighting system to identify gaps and research opportunities. For this purpose, a bibliometric literature review was carried out in the SCOPUS database. Among the results obtained, it was found that harmonic distortions in LED are helpful for research and that there has been an increase in studies focused on the theme over the last 10 years. The present work also showed that there are research gaps to be developed. [ABSTRACT FROM AUTHOR]

The development and popularization of LED technology has greatly satisfied people's pursuit of visual effects, but the attendant large amount of light radiation has also caused people's concern about the safety of light biology. At present, most of the known white LED production methods are using blue LED chips to stimulate yellow phosphors, and finally mixed into white light, resulting in rich blue components. At present, the harm of blue light radiation is one of the most important light radiation hazards to human beings. In this paper, the principle of blue light hazard, hazard evaluation mechanism, and the impact of blue light hazard on human beings are reviewed to reveal the severity of blue light hazard and provide theoretical basis and practical guidance for preventing blue light hazard. [ABSTRACT FROM AUTHOR]

LED technology has emerged as a promising non-thermal preservation method for highly perishable muscle foods like meat and fish. Muscle foods are most susceptible to spoilage due to their high moisture content and nutrient density, which create an ideal environment for microbial growth, chemical oxidation, and enzymatic activity, which negatively alter their quality. LED treatment offers an effective solution by significantly reducing microbial loads and extending shelf life without adversely affecting sensory and nutritional properties. Specific wavelengths of LED light induce microbial inactivation through mechanisms like DNA damage, lipid oxidation, and protein alteration. Studies have shown that LED treatment can preserve the fresh-like quality of muscle foods by mitigating common spoilage processes. The advantages of LED technology include its non-thermal nature, ability to integrate with other preservation methods, and controllability in terms of intensity and wavelength. This enables for tailored applications based on food type and spoilage risks. As consumer demand grows for safe, chemical-free food options, LED technology addresses this need while enhancing food safety and quality. Further research is encouraged to optimize LED applications in various muscle food preservation contexts. With its exceptional ability to produce DNA damage in bacteria, inactivate enzymes, and malfunction biological activities, LED could serve as an inexpensive processing intervention to safeguard the quality of meat and seafood products. This review underscores the potential of LED technology as a promising alternative to traditional preservation methods for decontamination of muscle food. • This review paper highlights the applications of LED for preservation of muscle foods like meat and fish. • LED treatment shows microbial inactivation due to microbial DNA damage, lipid oxidation, and protein alteration. • No significant changes of sensorial attributes of meat and fish products were reported after the LED treatment. • LED treatment shows minimal effect on physicochemical stability of meat and fish. [ABSTRACT FROM AUTHOR]

Abstract The currently secondary education needs the contribution of new techno-pedagogical resources, where the resource, teaching and learning skills are integrated to motivate students in their learning. For this reason, the field of holographics is presented as a dynamic alternative to the growing use of image projectors. However, these resources are not available to teachers and educational institutions because of their high costs. This research seeks to show how led-based technologies can be applied in secondary education, so allow the classroom attention of students and improve their interest in learning through the use of the 3D Holographic LED-Fan Display. In this way, the objective is to improve the student’s motivation for learning using current resources according to the realities of the current context of education, which may not have availability of mobile devices due to their high costs, thus they have not been considered for the present study. The research approach is a mixed methodology combining qualitative and quantitative information through an educational study case applied to the Kléber Franco Cruz School with the intervention of pre-professional practices carried out by the Technical University of Machala in Ecuador, through the realization of an integrative knowledge project with students with different profiles according to their curriculum, in order to face the different challenges of teaching.

In recent years, Brazil has experienced several crises of electric energy, and in the face of this situation, there is a concern to apply consumer reduction actions based on the government program PROCEL. Public lighting, in particular, is one of the areas where energy efficiency actions can be applied through technological updating of lighting equipment. This study, therefore, aims to evaluate the impact of such a change in the electric sector. For that, pilot projects were considered with complete technological update of this park by LED technology. In this context, it was evaluated the reduction of the electric energy consumption and thus, presented a 10-year projection scenario in order to verify the benefits of the technological update in terms of electric energy consumption and reduction of the energy demand with some economic considerations and, consequently reduction in the energy bill of final consumers. In addition, this projection can be used to discuss the reduction of CO2 emissions, as upgrading of public lighting by LED technology will bring savings in consumption and energy production. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

LED technology is revolutionizing street and area lighting, offering 70-90% energy saving, extremely long lifetime, low maintenance costs and most importantly: improving lighting. Municipalities, state transport departments, ports, prisons and many others use LED technology for street lighting, highways, parking lots, high buildings, bridges, tunnels and general lighting. [ABSTRACT FROM AUTHOR]

Copyright of Revista Técnica Energía is the property of Centro Nacional de Control de Energia CENACE and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Solar simulators are a fundamental instrument to characterize solar cells parameters, as they can reproduce the operating conditions under which the solar cells are going to work. However, these systems are frequently big, heavy, and expensive, and a small solar simulator could be a good contribution to test small prototyping devices manufactured in research labs, especially if it could manage the irradiation at any wavelength interval in a custom way. We have designed, developed, and calibrated a small solar simulator made entirely with LEDs, no optics inside, and electronically controlled through a PC using an Arduino microcontroller. The whole structure is 3-D printed in black PLA plastic. The electrical current through the LEDs, and thus the spectral irradiance of the simulator, is controlled with a very intuitive LabVIEW interface. As our calibration proves, we have built an easily reproducible and low-cost Class AAA solar simulator in a central illumination area of 1 cm2, according to the IEC60904-9 standard. This means that the homogeneity in that area is under a 2% deviation in spatial terms, below 0.5% in temporal terms, and is a factor of a 3% close to the AM1.5G sun reference spectrum. The system can be built and used in any research lab to get quick tests of new small solar cells of any material. [ABSTRACT FROM AUTHOR]

High performance daylight LED lamps are compared with HID lamps for light bleaching of paper. The LED can be placed in closer proximity to the object than the HID lamps, causing a significantly increased, uniform light exposure. Two commercial LED systems with 4000 K and 6500 K colour temperature were installed in a convertible test device with a polypropylene tray in default exposure distance of 10 cm and 20 cm. A HID lamp in 60 cm and 120 cm distance served as a reference. Samples of two naturally aged rag papers were bleached with both LED systems and with the HID while immersed in water. All three light sources increased brightness (CIELAB L*), though the LEDs with 4000 K colour temperature were most effective. They had no negative effect on the molar mass and the cellulose carbonyl group content while LEDs with 6500 K colour temperature caused molar mass decrease and carbonyl group increase. LEDs of a 4000 K or similar colour temperature are a promising option for improved light bleaching of paper, reducing the treatment and aqueous exposure time and eliminating UV radiation. [ABSTRACT FROM AUTHOR]

The developments in the communication technologies have yielded many existing and envisioned data transmission architectures such as 5G WiFi, green communication, body-in nano-communication, neutrino communication, inter-planets communication, gravitational communication. The widespread use of these promising technologies in the very near future is not out of reach anymore. From echological perspective, among these technologies, green communication known as also energy efficient communication that mitigates green house gas (CO2) emissions which is a major contributor to the climate change equation and decrease the overall energy consumption becomes vitally important for human beings. Therefore, the need for greener solutions for wireless technologies has emerged by increasing the attention of government, academia, and industry. VLC, new emerging dual-use technology has the potential of low energy consumption and allows huge, licence free bandwidth that allows low-cost broadband communication in the industrial, scientific, and medical (ISM) band with respect to overcrowding of the radio frequency (RF) spectrum and differs from radio frequency communication in both baseband signal format and optical power constraints and also less harmful to human health compared with IR communication. Therefore being a potential research focus for all the next-generation communications and networks designers, the researchers reengineer the function of indoor lighting and address the wireless capacity challenge. However, there exist many common significant regulatory and technical challenges to be addressed for the practical realization of this new emerging technology before its widespread acceptance, such as to find a way to achieve Gb/s transmission without affecting the illumination, to obtain adequate illuminance according to various environments under power efficient dimming control schemes, to achieve enhanced lighting efficiency, to provide modulation scheme compatibility with the dimming system, mobility management, duplex communication, multipath transmission channel characteristics, outdoor communication, reliability, channel coding, network coverage and to publish timely standards. Inspired by these challenges, many researchers are currently engaged in developing innovative design paradigms to address the energy efficiency challenges of existing and envisioned VLC systems for developing green VLC solutions. In this paper, the current state-of-the-art in energy efficient visible light communication is captured. LED-based VLC applications and solid state technology researches are presented. The next generation LED technologies proposed for high-speed communication for VLC applications are discussed and challenges that has to be overcome to increase the data-rate to Gb/s speeds while optimizing the power consumption are reviewed. The objective of this survey is to provide better understanding of the potentials for green VLC systems which is currently far from being fully recognized, and to motivate the research community to further explore this timely and vital topic.

Increase of energy efficiency in Serbia is one of the priority tasks. Sector of electric lighting offers great opportunities for increasing energy efficiency due to the rapid development of LED technology. Nowadays LED lighting is still expensive and have relatively little application in the domain of electric lighting. However, it is anticipated that LED products would soon greatly transform the electric lighting market. In recent years, LED technology has significantly improved, and constantly evolving. It is expected that advanced and future LED bulbs / lamps to be getting cheaper and with a better technical characteristics and that they will soon be dominant on the lighting market. Serbia must prepare for the LED future, creating appropriate legislation and promotion of appropriate incentive measures.

Background: Energy efficiency is becoming increasingly important in storing foods preserving their own characteristics and fruits and vegetables by drying in terms of selflife as well. Objectives: Since the Black Sea Region of Turkey is rainy and extremely humid during the harvest period of fruits and vegetables, the region is not suitable for natural drying of fruits and vegetables. For this reason, additional energy is needed for drying in the region. The Prunus domestica L. fruit that grown naturally in the Black Sea Region was dried using LED technology in a short time with minimum energy and preserving food properties, along with traditional methods. Methods: The fruits were dried at fixed lumen (10000 lumen) using the LED's of three different color temperatures (3000 K, 4000 K and 6500 K), along with traditional (sun drying) and conventional (using electrical heater) drying. In addition, the effects of drying conditions on watersoluble dry matter, vitamin C, total phenolic, total flavonoid and total antioxidant (FRAP, DPPH) properties were investigated. Results: Time-dependent drying curves of Prunus domestica L. at five different drying conditions and time-dependent changes of the dryer temperature with LED drying were obtained. Conclusion: The drying time with 3 different LED temperatures was found to be shorter than that of the drying time of sun drying and electric heater. It was concluded that, energy efficiency was better in LED drying than those of conventional methods. [ABSTRACT FROM AUTHOR]

Through the insight and visions of Danish lighting experts, this manuscript investigates relationships between future lighting technologies and practices and the expected impacts on energy and lighting consumption. The light-emitting diode (LED) will be the dominant technology of the future smart light systems. Though, energy efficiency is expected to improve, new market players will appear and new lighting opportunites will be exploited that, in turn, will increase the demand for light. A rebound effect is expected. The overall impact on the future consumption of energy is uncertain, so we conclude that political guidance is needed if society wants to assure the reduction of energy consumption through widespread diffusion of smart LED lights. [ABSTRACT FROM AUTHOR]

Light-emitting diodes (LEDs) are a promising technology with a potential to improve the irradiance efficiency, light quality, and the light spectrum for increasing plant yield and quality. In this experiment, we investigated the impacts of various LED light qualities, including 100% red, 100% blue, 70% red + 30% blue, and 100% white, on the growth and photosynthesis, phytochemical contents, and mineral element concentrations in lettuce ( Lactuca sativa L. cv. 'Grizzly') in comparison to normal greenhouse conditions. Photon flux of 300 µmol m s was provided for 14 h by 120 LEDs set on a 60 cm × 60 cm sheet of aluminum platform in the growth chambers, where plants were grown for 60 d. Fresh mass per plant was significantly higher when grown under 100% blue and 70% red + 30% blue LEDs compared to the other environments including greenhouse conditions. Phytochemical concentrations and a nutritive value of lettuce were also significantly affected by the light treatments. Chlorophyll and carotenoid concentrations increased in the plants grown under 70% red + 30% blue LEDs compared to those grown in the greenhouse. Vitamin C content was 2.25-fold higher in the plants grown under 100% blue LEDs compared to those grown in the greenhouse. Higher photosynthesis and maximal quantum yield of PSII photochemistry were also observed in the plants treated with LED lights. The application of LED light led to the elevated concentrations of macro-and micronutrients in lettuce possibly because of the direct effect of LED light and lower stress conditions in the growth chambers compared to the greenhouse. Although the mechanism of the changes in lettuce grown under LED is not well understood, the results of this study demonstrated that LED light could be used to enhance the growth and nutritional value of lettuce in indoor plant production facilities. [ABSTRACT FROM AUTHOR]

The present paper deals with energy-efficient street lighting using LED technology. Depending on the voltage applied the LED luminous flux may vary. To ensure an efficient street lighting it is necessary to implement an on / off street lighting system schedule according to the geographical location by taking as a reference the times when the sun rises and sets for each day of the calendar year and to change the luminous flux of street lighting depending on the time of night. There are time periods during the night hours when the street lighting is very important, for example on the early morning hours or right after the sunset. In the remaining time periods luminous flux of LED lamps can be reduced after a well defined program. These goals can be achieved by using a Mitsubishi Alpha 2 PLC (AL2-10MR-A type) with four normally open contacts and by implementing a specific electric scheme at the street lighting system switching points. [ABSTRACT FROM AUTHOR]

The developments in the communication technologies have yielded many existing and envisioned data transmission architectures such as 5G WiFi, green communication, body-in nano-communication, neutrino communication, inter-planets communication, gravitational communication. The widespread use of these promising technologies in the very near future is not out of reach anymore. From echological perspective, among these technologies, green communication known as also energy efficient communication that mitigates green house gas (CO2) emissions which is a major contributor to the climate change equation and decrease the overall energy consumption becomes vitally important for human beings. Therefore, the need for greener solutions for wireless technologies has emerged by increasing the attention of government, academia, and industry. VLC, new emerging dual-use technology has the potential of low energy consumption and allows huge, licence free bandwidth that allows low-cost broadband communication in the industrial, scientific, and medical (ISM) band with respect to overcrowding of the radio frequency (RF) spectrum and differs from radio frequency communication in both baseband signal format and optical power constraints and also less harmful to human health compared with IR communication. Therefore being a potential research focus for all the next-generation communications and networks designers, the researchers reengineer the function of indoor lighting and address the wireless capacity challenge. However, there exist many common significant regulatory and technical challenges to be addressed for the practical realization of this new emerging technology before its widespread acceptance, such as to find a way to achieve Gb/s transmission without affecting the illumination, to obtain adequate illuminance according to various environments under power efficient dimming control schemes, to achieve enhanced lighting efficiency, to provide modulation scheme compatibility with the dimming system, mobility management, duplex communication, multipath transmission channel characteristics, outdoor communication, reliability, channel coding, network coverage and to publish timely standards. Inspired by these challenges, many researchers are currently engaged in developing innovative design paradigms to address the energy efficiency challenges of existing and envisioned VLC systems for developing green VLC solutions. In this paper, the current state-of-the-art in energy efficient visible light communication is captured. LED-based VLC applications and solid state technology researches are presented. The next generation LED technologies proposed for high-speed communication for VLC applications are discussed and challenges that has to be overcome to increase the data-rate to Gb/s speeds while optimizing the power consumption are reviewed. In this paper, the current state-of-the-art in energy efficient visible light communication is captured. LED-based VLC applications and solid state technology researches are presented. The next generation LED technologies proposed for high-speed communication for VLC applications are discussed and challenges that has to be overcome to increase the data-rate to Gb/s speeds while optimizing the power consumption are reviewed. [ABSTRACT FROM AUTHOR]

The residential sector represents about 30% of the total energy demand in Europe. Included in this percentage, lighting consumption is one of the basic end uses in all households and it may come to represents 15–20% of the total electricity bill. This figure can be reduced using advanced control techniques or more efficient lighting technologies, requiring previous detailed information about current consumption patterns. In this context, bottom-up stochastic models are established as the main tools to study new energy savings. In this paper, a high-resolution stochastic model for simulating lighting consumption profiles was developed, obtaining both daily active and reactive instantaneous power demand profiles, with a 1-min resolution. The model takes into account the number of household residents and differentiates between weekdays and weekends. Moreover, the monthly and annual amounts of electricity demanded by lighting in Spanish households were simulated. The proposed model was also used to quantify the impact of LED technology's penetration into domestic lighting systems on consumption patterns. Research has revealed the existence of two consumption peaks matching with morning and evening. Although these peaks are hard to shift since they are due to human behavior, they are easy to reduce through the improvement of lighting systems. [ABSTRACT FROM AUTHOR]

The primary goal of the project is to design a lighting system that provides the highest visual comfort and conserves energy for different uses and furniture layouts, which considers that the design of the house will be used by many different users. Indoor system designs vary in layout, goals and optics with two levels of intervention: when initially furnished and during daily use. Lighting is managed by a building automation system, which is equipped with motion and daylight sensors and human interfaces with user scenarios. An outdoor design that requires only a standalone system and is powered by photovoltaic and eolic devices has been developed. All systems incorporate LED technology and have been custom-developed for Med in Italy, which resulted in new patents. Lighting system projects have been involved in several competitions, e.g., Med in Italy placed in the Solar Decathlon in Architecture, Electrical Energy Balance, House Functioning, and Sustainability and took third place in the final ranking. Further research developments are in progress and will be seen in next Solar Decathlon Europe in Paris in 2014. This paper describes the project, installation and analyses of the energy savings that the Medinitaly system can achieve compared with traditional solutions. Simulation data are compared with measured data from the period of the Solar Decathlon competition. [ABSTRACT FROM AUTHOR]

Our exposure to blue light from artificial sources such as indoor lights (mainly light-emitting diodes [LEDs]) and electronic devices (e.g., smartphones, computer monitors, and television screens), has increased in recent years, particularly during the recent coronavirus disease 2019 lockdown. This radiation has been associated to skin damage across its potential in generating reactive oxygen species in both the epidermis and the dermis, skin water imbalances and of potential activating melanin production. These circumstances make it important to determine whether current blue light exposure levels under artificial illumination and electronic devices exposure can cause the previously indicated disorders as compared to solar UV and visible radiation in a typical summer day. Blue light accounted for 25% of the sun's rays, approximately 30% of radiation emitted by electronic devices, and approximately from 6% to 40% of that emitted by indoor lights. The reference equations showed that the sun was the main source of effective irradiance for immediate and persistent pigmentation as well as for potential oxidative stress in our skin. Effective blue light exposure to artificial devices is significantly lower than the solar contribution. However, its contribution must be considered as accumulative dose effect, and especially in people with hypersensitivity promoting skin hyperpigmentation. • LED technology is being increasingly used in electronic devices and to provide both indoor and outdoor lighting. • Normal daily dose of blue light emitted by LED devices is less than 5% compared to sun for inducing skin pigmentation. • Long time LED overexposure as during the COVID-19 lockdown enhance risk factors for hyperpigmentation. [ABSTRACT FROM AUTHOR]

• PDT is booming with continuing development of new photosensitizers and medical indications. • Current light devices give only limited choice of treatment area and spectral qualities. • We show a new LED device with an array of different light colours from blue to infrared to spectrally match with the absorption spectra peaks of a wide range of photosensitizers. • The device allows the irradiation field to be close matched to the lesion area. • Preliminary results show the promise of this use easy and low-cost LED device for different PDT modalities. One of the key aspects of photodynamic therapy is the light source that is used to irradiate the lesion to be treated. The devices used must ensure that their emission spectrum matches the absorption spectrum of the photosensitizer, so that treatment radiation is delivered only on the target area, without irradiating healthy tissue at superficial or deep levels. Irradiance values must be adequate in order to avoid thermal damage, exceed the oxygen replenishment rate and avoid long treatment times. Furthermore, the device should be user-friendly, inexpensive, and able to be adapted to different photosensitizers. We have developed an easy-to-use and highly customizable device based on LED technology. Its innovative geometric design allows radiation to be delivered to a small treatment surface, since the LEDs are arranged in three arms, the configuration of which directs their radiation on the treatment point. Different high-power color LEDs are disposed on the arms, and can be independently selected based on the most effective wavelengths for exciting the different photodynamic therapy photosensitizers. We have tested the prototype in 5 different patients (1 actinic keratose, 1 actinic cheilitis, 1 superficial basal cell carcinoma and 2 Bowen's disease) and after 1–2 sessions of total cumulative dose of 25–50 J / cm2, 100% clearance of lesions were obtained. Our device can be used by any professional in the field, whether for medical or research purposes. It facilitates the development of treatment protocols and trials with different photosensitizers. A key aspect of photodynamic therapy is the light source used to radiate the lesion to be treated. We have developed an LED-based array capable of emitting colors from blue to infra-red so that the emission spectrum can be matched to the absorption spectrum of many photosensitizers, with the capacity to focus the light beam on the lesion area, and with LED energy control for irradiance selection. So, healthy tissue can be protected and treatment duration as well as light spectrum can be easily controlled. Preliminary tests in a set of patients and different skin lesions show our device to be a promising easy to use, low cost and easily controllable light source. [Display omitted] [ABSTRACT FROM AUTHOR]

A proposal of current source based on a linear‐assisted DC/DC converter is presented, in which a linear voltage regulator assists a switching DC/DC converter in order to obtain a compact circuit with advantages of both alternatives; i.e. high efficiency (similar to the switching converter), and low output ripple and fast reaction to the load changes (similar to the linear regulator). To reduce the power dissipation in the linear regulator, it is considered as an assisted circuit for providing just a little fraction of the load current. Furthermore, this stage provides the required clock signal for the switching counterpart, resulting in reduction of the complexity in the design of the control scheme for the switching converter and a compact topology, especially for on‐chip practical implementations, since no output capacitors are required. This last advantage provides the possibility of obtaining good‐performance current‐source drivers for LED technology in lighting applications. The implementation and results indicate that the proposed linear‐assisted DC/DC regulator‐based current source can achieve a notably compacting and higher performance, while consuming less power in comparison to linear alternatives. [ABSTRACT FROM AUTHOR]

Electrical and thermal consumption related to buildings, whether civil, commercial, public, or of any other kind, is very much in focus today. With today's targets for energy savings, reduction of consumption, and environmental impact, it is necessary to carry out energy retrofits to modernize installations and their management. The realization of an effective improvement requires a careful analysis of the case study because each category of building has different requirements such as different load profiles and different installations and needs. This was carried out by studying the electrical and thermal load profiles. A good initial energy audit can provide the retrofit solutions capable of achieving the reduction of energy consumption and the emission of climate-changing gases into the atmosphere. A case study, carried out by the Department of Engineering of Palermo, showed how it is possible to perform an energy retrofit to modernize the energy system of the student dormitory at the University of Palermo. The paper presented a study carried out by programming a series of interlinked calculations in Microsoft Excel. In order to quantify the energy savings of the structure under examination, it is necessary to enter some input data, thanks to which all the formulas implemented in the calculation software were automatically completed. The programming of the calculations makes it possible to carry out an energy retrofit with interventions on the building envelope and the installations. The desire to program an automated calculation by modifying only the input data is intended to replicate a study on other buildings with the same peculiarities. In this way, it is possible to verify which retrofit hypotheses would be useful to upgrade old public administration buildings. In the analyzed case study, 65% of electrical energy and 33% of thermal energy could be saved by replacing generation systems, installing a co-generator, replacing windows, and replacing lamps with LED ones. [ABSTRACT FROM AUTHOR]

Abstract: Artists making three-dimensional art objects have an idea in their minds about how to illuminate their creations. For museums and galleries to illuminate these objects successfully according to the ideas of the artist, the types of light sources and their locations must be known. To fulfil this requirement, we propose a lighting coordinate database (LCD) to establish the coordinates of light sources. We describe two possible methods of obtaining data for this database: a computer software method and a hardware method. The head of Michelangelo''s David is used to test the applicability of the two methods. In the software method, the scanned image of David''s head is illuminated on the computer screen and data for the location of light sources are created. In the hardware method, a second set of data is created by illuminating a scale model of David using light emitting diodes (LED). [Copyright &y& Elsevier]