Light-emitting Diode Light Research Articles

Life cycle assessment of high-power white LEDs for indoor lighting in the context of Hong Kong

The introduction of white light-emitting diodes (LEDs) is one of the key innovations that has revolutionized the lighting industry due to its multiple benefits. Despite their advantages, there is a gap in the environmental impact information of the recently developed high-power LED products within the whole lifecycle, which is a key step to achieve sustainable and green development. This life cycle assessment (LCA) is conducted by considering the cradle-to-grave system boundary. The functional units considered are a LED and compact fluorescent lamp (CFL) of 40 million lumen-hours (lm-h) used for indoor applications over an operating time of 20 000 h. In this study, the LCA was carried out using the SimaPro software and built-in ecoinvent database V2.2 with appropriate life cycle inventory data. The analysis results indicate that: (1) the LED-package has a dominant environmental impact followed by the LED driver while the housing and corrugated-board packaging materials showed the least negative effect to the ecosystem during the manufacturing phase. On the contrary, the CFL drivers are dominant followed by the light sources in the case of CFLs. From the lifecycle stages, the usage-phase showed a predominant environmental effect, mainly due to the energy consumption and sources of energy production. (2) A scenario analysis on the sources of electricity production revealed that prospective sources (70% natural gas, 25% nuclear and 5% pumped storage) of energy production lowered the environmental impact compared to the current electricity mix. These proposed electricity generation production sources provide a 61% reduction in the global warming potential in light sources for Hong Kong.

Artificial intelligence models for validating and predicting the impact of chemical priming of hydrogen peroxide (H2O2) and light emitting diodes on in vitro grown industrial hemp (Cannabis sativa L.).

Industrial hemp (Cannabis sativa L.) is a highly recalcitrant plant under in vitro conditions that can be overcome by employing external stimuli. Hemp seeds were primed with 2.0-3.0% hydrogen peroxide (H2O2) followed by culture under different Light Emitting Diodes (LEDs) sources. Priming seeds with 2.0% yielded relatively high germination rate, growth, and other biochemical and enzymatic activities. The LED lights exerted a variable impact on Cannabis germination and enzymatic activities. Similarly, variable responses were observed for H2O2 × Blue-LEDs combination. The results were also analyzed by multiple regression analysis, followed by an investigation of the impact of both factors by Pareto chart and normal plots. The results were optimized by contour and surface plots for all parameters. Response surface optimizer optimized 2.0% H2O2 × 918 LUX LEDs for maximum scores of all output parameters. The results were predicted by employing Multilayer Perceptron (MLP), Random Forest (RF), and eXtreme Gradient Boosting (XGBoost) algorithms. Moreover, the validity of these models was assessed by using six different performance metrics. MLP performed better than RF and XGBoost models, considering all six-performance metrics. Despite the differences in scores, the performance indicators for all examined models were quite close to each other. It can easily be concluded that all three models are capable of predicting and validating data for cannabis seeds primed with H2O2 and grown under different LED lights.

High β-carotene accumulation in transgenic eggplant fruits grown under artificial light.

Eggplant (Solanum melongena L.) fruits are known to contain few carotenoids such as β-carotene, which are abundant in congener tomato fruits. In a previous study, we introduced a fruit-specific EEF48 gene promoter-driven crtB gene encoding phytoene synthase (PSY) of Erwinia uredovora into eggplant 'Senryo No. 2'. The transgenic plants grown in a greenhouse set fruits that accumulated β-carotene (∼1.67 µg g-1FW) in the T0 and T1 generations. In the present study, we grew T1 and T2 generations of the transgenic eggplant plants in artificial climate chambers to investigate their fruit set and β-carotene accumulation. No clear difference in β-carotene accumulation was observed in the fruit of transgenic plants grown under either HID (high-intensity discharge) or LED (light-emitting diode) light, or between T1 and T2 generations. The β-carotene accumulation (8.83 µg g-1FW on average) was approximately 5 times higher than the previous results obtained from greenhouse-grown plants. However, the fruit weight and size of the T-DNA (+) plants were significantly smaller than that of their null-segregant T-DNA (-) plants derived from the same line, suggesting that β-carotene accumulation may inhibit fruit development. Considering that a part of plants grown under LED irradiation failed to set fruits or set smaller fruits than those grown under HID irradiation, the light condition in the LED chamber may not be sufficient to promote fruit development. The present results are expected to provide valuable information for the selection of transgenic eggplants with high β-carotene content in fruit under artificial lighting.

Dual-channel on-chip data transmission system using UV light based on GaN-on-Si wafer

The ultraviolet photonic integrated circuits possess application prospects in ultraviolet (UV) microscopy, bio-sensing, on-chip data communication, etc. Herein, we propose a UV light on-chip data transmission system based on epitaxial GaN on silicon. This simple system includes a light-emitting diode light source, a modulator, a Y-branch waveguide and two photodetectors. Both direct modulation and indirect modulation are configured into this system and demonstrated by experiment. Dual-channel communication is also implemented through Y-branch waveguide. As all the active devices share the same InGaN/AlGaN multiple quantum wells (MQW) diode structure, this 378 nm UV light data transmission system can be monolithically integrated through the compatible manufacturing processes. By adopting the integrated MQW modulator with relatively large active region area, a significant modulation effect can be achieved with modulation depth greater than 48% under reverse bias of 20 V.

Leading Light: The Impact of Advanced Lighting Technologies on Indonesia's Office Industry

Addressing concerns over resource scarcity and environmental sustainability necessitates a global shift towards sustainable energy, notably facilitated by adopting Light-Emitting Diode (LED) lamps. This transition is pivotal for ensuring global energy security and aligning with sustainability goals. This study endeavors to comprehensively analyze potential energy savings achievable through the transition from Fluorescent (FL) lamps to LED lamps within industrial offices. Emphasis is placed on highlighting the central role of energy efficiency. Utilizing false color rendering as a visual guide, the study systematically identifies areas where FL lamps inadequately illuminate. The findings prompt recalculations for determining optimal room illumination achievable through implementing LED lamps. Lux calculations are then employed to showcase the superior illumination offered by LED lamps, revealing consistent monthly cost savings of 35%, particularly when harmonized with Building Management System (BMS) control in industrial office buildings. The study's results indicate that LED lamps provide superior illumination, yielding a noteworthy 35% monthly cost savings, especially when integrated with BMS control. Lamps contribute modestly (21-30%) to overall energy consumption, while air conditioning commands a substantial 60%, underscoring the critical need for advanced lighting technology. This need is emphasized, particularly with Solar PV as a sustainable energy source. Understanding technological developments, especially in BMS, is crucial to optimize energy efficiency in industrial offices. The imperative implementation of LED lighting technology is a critical solution to address resource scarcity and environmental concerns in industrial offices. The efficacy of LED lamps in achieving significant energy savings, especially when coupled with advanced systems like BMS and complemented by renewable energy sources such as Solar PV. The conclusion stresses the significance of staying abreast of technological advancements to foster sustained progress towards energy-efficient and environmentally conscious practices within industrial environments.

Microleakage of two resin composites by using different light curing systems

This study was conducted to evaluate marginal microleakage of two resineomposite (Glacier resin composite and Filtek P 60 resin composite) either cured witheonventional light cure unit ( Astralis 5) or light emitting diodes (LED) light cure unit»Radii). Forty class V cavities were prepared in 20 extracted second premolars, onebuccaly and one palataly in each tooth. Each cavity was located lmm coronal toeementoenamel junction and lmm apical to it. The teeth were randomly divided into 4groups, each group of five teeth (I0 cavities): Group I was filled with Glacier resincomposite and cured with LED curing unit. Group ll filled with Glacier and curedin ith Astralis 5 curing unit. Group lll filled with Filtek P60 resin composite and curedv- ith LED curing unit. Group IV filled with Filtek P 60 and cured with Astralis curingxnit. The teeth were stored in distilled water for seven days. Then the apices of theteeth were sealed with sticky wax and the teeth were covered with two layers of nailvamish except lmm around the restoration. The teeth were immersed in 0.5% basicfaehsin dye for 24 hours at 37°C in the incubator and then were longitudinallyxctioned in a buccolingual direction and the extent of dye penetration was recorded.The statistical analysis of the result revealed that the use of LED light cure unit,results in highly significant reduction in the microleakage occlusally and gingivally

Growth, leaf anatomy, and photosynthesis of cotton (Gossypium hirsutum L.) seedlings in response to four light-emitting diodes and high pressure sodium lamp

BackgroundLight is a critical factor in plant growth and development, particularly in controlled environments. Light-emitting diodes (LEDs) have become a reliable alternative to conventional high pressure sodium (HSP) lamps because they are more efficient and versatile in light sources. In contrast to well-known specialized LED light spectra for vegetables, the appropriate LED lights for crops such as cotton remain unknown.ResultsIn this growth chamber study, we selected and compared four LED lights with varying percentages (26.44%–68.68%) of red light (R, 600–700 nm), combined with other lights, for their effects on growth, leaf anatomy, and photosynthesis of cotton seedlings, using HSP lamp as a control. The total photosynthetic photon flux density (PPFD) was (215 ± 2) μmol·m−2·s−1 for all LEDs and HSP lamp. The results showed significant differences in all tested parameters among lights, and the percentage of far red (FR, 701–780 nm) within the range of 3.03%–11.86% was positively correlated with plant growth (characterized by leaf number and area, plant height, stem diameter, and total biomass), palisade layer thickness, photosynthesis rate (Pn), and stomatal conductance (Gs). The ratio of R/FR (4.445–11.497) negatively influenced the growth of cotton seedlings, and blue light (B) suppressed stem elongation but increased palisade cell length, chlorophyll content, and Pn.ConclusionThe LED 2 was superior to other LED lights and HSP lamp. It had the highest ratio of FR within the total PPFD (11.86%) and the lowest ratio of R/FR (4.445). LED 2 may therefore be used to replace HPS lamp under controlled environments for the study of cotton at the seedling stage.

Combined effect of LED light color and nitrogen source on growth, pigments composition and oxidative stress in Arthrospira platensis

Artificial lighting with light-emitting diodes (LED) is proposed as a suitable solution to reach stable yearly production of high value molecules from microalgae under unfavorable climates. However, available studies are inconsistent regarding the effect of LED color on cultures performance. This study examined the response of Arthrospira platensis to three different LED lighting conditions (white, red, and red-blue 70:30) when is grown in three media with different nitrogen composition. Growth, phycobiliproteins and lipophilic pigments content were determined. In addition, antioxidant enzymes (GST, lipid peroxidation) and morphology were analyzed to enlighten new perspectives on the health status of microalgae production.The highest biomass production (2.13 g/L) was achieved under red LED when Zarrouk medium was supplemented with urea. Regarding pigment production (phycobilins, chlorophyll a and β- carotene), the most desirable combination was red: blue together with urea supplementation. In addition, this combination showed a high biomass production (2.03 g/L) and low expression of antioxidant enzymatic activity. This research shows a novel combination of LED technology and nutrients to enhance microalgae biomass production and high value metabolites with a lower economic cost.

Smart Hydroponic Farming System Integrated with LED Grow Lights

Vertical farming, including hydroponics, is a growing trend in the agricultural sector due to the increasing demand for food and urbanisation. Thus, hydroponics can save space and achieve faster plant growth compared to traditional farming methods. The concept of smart farming has been applied in this study to improve the ease of control and monitoring of hydroponic systems. The effects of light-emitting diodes (LEDs), light distance, and colour (purple and white) on water spinach growth in a hydroponic system were investigated. Additionally, an Internet of Things (IoT) controller was developed and implemented to facilitate the use of the system in an indoor hydroponic-based environment system. Based on the results, the distance between the LED light of 15 cm and the plants and the colour of the LED light (white) can positively impact plant growth in a hydroponic system. Using an IoT controller also allows for continuous monitoring and control of factors that influence plant growth. Hence, this research would catalyse the local smart hydroponic farming system for improved deliverables.

Nighttime light in China's coastal zone: The type classification approach using SDGSAT-1 Glimmer Imager

Nighttime Light (NTL) is highly concentrated in China's coastal zone, leading to negative health impacts on both humans and wildlife. Particularly, in recent years, the widespread adoption of broad-spectrum Light-Emitting Diode (LED) light, a low-carbon technology providing substantial increases in luminosity, has led to certain ecological consequences. Thus, information regarding spatial distribution and composition of different NTL types is essential for formulating sustainable strategies that balance nighttime public security, energy consumption, and ecosystem conservation. However, the availability of such information remains limited. To address this challenge and meet the demand, we developed two new light indices, namely the Ratio Red Light Index (RRLI) and Ratio Blue Light Index (RBLI), based on SDGSAT-1 Glimmer Imager (GLI) multispectral NTL data. We then proposed a threshold method and applied it to the entire coastal zone of China to identify White LED (WLED), Red LED (RLED), and Other lights (Other). Results showed the following. (1) In the coastal zone of China, the total lighting area was 20,517 km2, including 20,257 km2 of terrestrial lights and 260 km2 of offshore lights; (2) WLED light covered 67% (13,727 km2) of all lighting areas, while RLED lights accounted for only 1% (220 km2); (3) Guangdong had the largest lighting area (5221 km2), with the proportion of WLEDs being the highest among all coastal provinces (almost 90%); (4) The proportions of lighting areas were relatively low in Guangxi, Liaoning, and Hebei. This study represents the first attempt to identify NTL types over large regions at a finer spatial resolution. The approach proposed, including the light indices of RRLI and RBLI, as well as the defined thresholds, is universal and robust for use in NTL type classification. The developed lighting type map, containing comprehensive information on the spatial distribution and composition of NTL, could facilitate the sustainable management of China's coastal zones.

The Growth and Tuber Yield of Potatoes (Solanum tuberosum L.) under Varying LED Light Spectrums in Controlled Greenhouse Conditions

Plant growing using light-emitting diodes (LEDs) in a controlled environment is a revolutionary and innovative idea, regardless of the external environmental disturbances. Studying the growth and tuber yield of potatoes (Solanum tuberosum L.) in an LED-based plant factory system is a relatively innovative concept. The current study was conducted in a plant factory to evaluate the effects of different LED spectral compositions on potato tuberization. Potato tuberization was analyzed under six different LED light spectral combinations with irradiances of 300 mol m−2 s−1, with natural light considered the control treatment. The findings stated that the L2 treatment (red70 + blue20 + white10) increased the plant height, branch number, and biomass accumulation, while photosynthetic pigments and photosynthetic activity increased significantly in L5 (red60 + blue20 + green10 + white10). Higher gibberellic acid (GA3) content was recorded in L1 (red70 + blue30), whereas the tuber number and tuber fresh weight were recorded in L3 (red70 + blue20 + green10) and L7 (natural light), respectively. On the other hand, a higher number of smaller-sized tubers were observed in L5, while L2 and L4 (red70 + blue20 + far-red10) resulted in a higher number of medium-sized tubers. In conclusion, a high proportion of red and blue light, along with white and far-red light, increased the plant height, branch number, plant biomass, and production of small- and medium-sized tubers. On the other hand, the inclusion of green light with red and blue enhanced the chlorophyll content, photosynthesis, and leaf expansion, and promoted the production of smaller-sized tubers. Finally, with regard to tuberization, the treatment using L4 followed by L2 outperformed the other treatments.

Quantum dots boost large-view NIR-II imaging with high fidelity for fluorescence-guided tumor surgery

Owing to the high spatiotemporal resolution, the second near-infrared (NIR-II) imaging window can provide high imaging contrast with diminished tissue autofluorescence and suppressed photon scattering to pinpoint the locations for tumor surgery. Due to the unique optical properties and excellent fluorescence performance, quantum dots (QDs) are regarded as ideal nanoprobes for fluorescence-guided surgery (FGS). Moreover, QDs can be excited by a variety of light sources owing to the continuous and wide absorption ranges. Herein, light-emitting diode (LED) was used as the excitation source of QDs-based nanoprobes to realize FGS of tumor with high resolution. Since the LED light could irradiate a large region with consistent light intensity, signal distortion at the edge of imaging field was avoided. The signal intensity of the view edges under LED excitation can be improved by about 5 times compared to laser excitation. Therefore, more micro-vessels and smaller tumors (Vtumor < 5 mm2) could be detected, thus providing more precise guidance for tumor resection surgery.

Satellite Hyperspectral Nighttime Light Observation and Identification with DESIS

The satellite imagery of nighttime lights (NTLs) has been studied to understand human activities, economic development, and more recently, the ecological impact of brighter night skies. The Visible Infrared Imaging Radiometer Suite (VIIRS) Day–Night Band (DNB) offers perhaps the most advanced nighttime imaging capabilities to date, but its large pixel size and single band capture large-scale changes in NTL while missing granular but important details, such as lighting type and brightness. To better understand individual NTL sources in a region, the spectra of nighttime lights captured by the DLR Earth Sensing Imaging Spectrometer (DESIS) were extracted and compared against near-coincident VIIRS DNB imagery. The analysis shows that DESIS’s finer spatial and spectral resolutions can detect individual NTL locations and types beyond what is possible with the DNB. Extracted night light spectra, validated against ground truth measurements, demonstrate DESIS’s ability to accurately detect and identify narrow-band atomic emission lines that characterize the spectra of high-intensity discharge (HID) light sources and the broader spectral features associated with different light-emitting diode (LED) lights. These results suggest the possible application of using hyperspectral data from moderate-resolution sensors to identify lamp construction details, such as illumination source type and light quality in low-light contexts. NTL data from DESIS and other hyperspectral sensors may improve the scientific understanding of light pollution, lighting quality, and energy efficiency by identifying, evaluating, and mapping individual and small groups of light sources.

(276) Light Emitting Diodes (LED) as a Potential Therapy for Erectile Function: A Preclinical Study in a Cavernous Nerve Injury Model

Abstract Introduction Erectile dysfunction (ED) induced by nerve injury including prostatectomy poorly responds to PDE5 inhibitor and requires invasive treatment. Light emitting diodes (LED) in some spectral range, is able to irradiate cells without overheating for its low energy consumption and to enhance mitochondrial metabolism, intracellular energy transfer, and thereby cell proliferation and tissue regeneration in some organs. We, herein, investigated whether and how LED therapy may improve penile erection in mouse cavernous nerve injury (CNI) - induced ED model Objective To identify the optimal LED parameters using molecular, histological, and erectile function analysis in cavernous nerve injury. Methods Eight week old male mice (n=120) were divided into 5 age-matched groups, a sham operation group receiving heat treatment, a CNI group receiving heat treatment, a CNI group receiving red light of LED (wavelength; 660 ±3% nm), a CNI group receiving near infrared light of LED (wavelength; 830 ±2% nm), and a CNI group receiving combination of both LED light. Mice were exposed to LED light for 30 minutes on the ventral side including penis for 5 consecutive days after CNI operation. Molecular study, histopathological analysis of the penis and erectile function test were done 2 weeks following the treatment in each subject. Results CNI group with heat treatment had much lower maximum and total ICP than sham control group. In contrast, three groups with LED light irradiation exhibited considerably improved maximum and total ICP, and the group with both LED treatments had the best erectile performance, reaching 90% of the sham surgery group. Histologically, mice treated with RED, NIR, or LED irradiation had more cavernous pericytes and endothelial cells than CNI mice after sham operation. In addition, all three CNI groups with various LED lengths improved neuroprotection and brain regeneration in CNI mice. All groups treated with LED showed increased expression of βIII-tubulin, neurofilament-1, and nNOS in cavernous tissue and dorsal nerve bundle. Additionally, LED treatment in three groups, particularly the combination group, significantly increased βIII-tubulin, S100, and myelin basic protein levels, indicating axonal integrity or expansion in the dorsal root and major pelvic ganglions. Molecular analysis of downstream signals of neural regeneration or angiogenesis showed that 3 groups with LED treatment increased phosphorylated PI3K, neurotrophic factors like BDNF, NGF, and NT-3, and angiogenic factors like angiopoietin1 and vascular endothelial growth factor in cavernous tissue and llpopolysaccharide-treated PC-12 cells. The TUNEL assay and BrdU staining of these tissue and cells showed lower cell apotosis and proliferation in LED-treated groups. Conclusions The results show that LED therapy with RED, NIR, preferably combination of each wavelength improves penile erection by neural progection or regeneration in cavernous nerve injury induced-ED. This noninvasive therapy may be useful in near future for ED refractory to PDE5 inhibitor. As far as we are aware, this is the first research to demonstrate the advantage of LED therapy, low level in sexual dyfunction field. Disclosure No.

Effect of different light intensities on agronomic characteristics and antioxidant compounds of Brassicaceae microgreens in a vertical farm system

Microgreens are vegetable or edible herb shoots harvested in the early stages of development. They have an important number of bioactive compounds and add color, texture, and flavor to dishes and salads. Given their benefits, small size, and high market prices, they can grow in indoor systems, where light is determinant. This study aimed to evaluate the effect of different light intensities on agronomic characteristics, color, chlorophylls and carotenoids content, and antioxidant activity represented by total phenolic content (TPC), eliminate, and antioxidant capacity (AC) in four Brassicaceae species in two colors (green and red). The experiment was conducted in a controlled light-emitting diode (LED) environment growth chamber (day/night temperatures of 25/20 ± 1.2°C, 16 h photoperiod, and 79 ± 2% relative humidity). Three light intensities were used for microgreen growth with the same LED light spectrum: low (120 ± 5.1 μmol m−2 s−1), medium (160 ± 3.6 μmol m−2 s−1), and high (210 ± 5.9 μmol m−2 s−1). Eight g of the seeds of green and red cultivars of cabbage, kale, mizuna, and mustard were sown in a plastic tray (64 cm x 35 cm x 6 cm) with a mixture of peat and perlite (1:2 = v: v). Overall, the high intensity increased dry matter percentage and dry weight, except in green and red kale and green cabbage cultivars. In contrast, low intensity promoted a larger hypocotyl in all species than with high intensity; moreover, it enhanced the cotyledon area in green and red mizuna. Cabbage, kale, and mustard green cultivars were greener under medium intensity, whereas the low intensity enhanced the purple color of mizuna. In addition, chlorophyll a and b increased under low intensity in most species except the red kale and mustard cultivars. The high intensity raises the antioxidant activity, promoting a higher TPC and AC. The findings revealed that the light intensity generated variations in agronomic characteristics, color, chlorophyll content, and antioxidant activity of Brassicaceae microgreens, and the changes were based on the specific species and cultivars.

Antimicrobial photodynamic effect of the photosensitizer riboflavin, alone and in combination with colistin, against pandrug-resistant Pseudomonas aeruginosa clinical isolates

IntroductionDevelopment of multi-, extensively-, and pandrug-resistant (MDR, XDR, and PDR) strains of Pseudomonas aeruginosa remains a major problem in medical care. The present study evaluated the effect of antimicrobial photodynamic therapy (aPDT) as a monotherapy and in combination with colistin against P. aeruginosa isolates. MethodsTwo P. aeruginosa isolates recovered from patients with respiratory tract infections were examined in this study. Minimum inhibitory concentration (MIC) of colistin was determined by the colistin broth disk elution (CBDE) and the reference broth microdilution (rBMD) methods. aPDT was performed using the photosensitizer (Ps) riboflavin at several concentrations and a light-emitting diode (LED) emitting blue light for different irradiation times with or without colistin at 1/2 × MIC concentration. ResultsBoth PA1 and PA2 isolates were identified as colistin-resistant P. aeruginosa with a MIC ≥4 μg/mL by the CBDE and MICs of 512 μg/mL and 256 μg/mL, respectively, by the rBMD. In aPDT, neither riboflavin nor LED light alone had antibacterial effects. The values of colony forming units per milliliter (CFU/mL) in both isolates were significantly reduced by LED + Ps treatments in a time-dependent manner (LED irradiation time) and dose-dependent manner (Ps concentration). In comparison with control, treatment with Ps (50 μM) + LED (120 s) and Ps (100 μM) + LED (120 s) resulted in 0.27 log10 CFU/mL and 0.43 log10 CFU/mL reductions in PA1, and 0.28 log10 CFU/mL and 0.34 log10 CFU/mL reductions in PA2, respectively, (P < 0.01). The best results were obtained after the combination of aPDT followed by colistin, which increased bacterial reduction, resulting in a 0.41−0.7 log10 CFU/mL reduction for PA1 and 0.35−0.83 log10 CFU/mL reduction for PA2 (P = 0.001). ConclusionsThis study suggests the potential implications of aPDT in combination with antibiotics, such as colistin for treatment of difficult-to-treat P. aeruginosa infections.

Blinded by the light: does heat or light enhance wild mosquito (Diptera: Culicidae) attraction to CO2-baited traps in the Great Salt Lake area?

The New Jersey Light Trap has been among the earliest trap models used for mosquito surveillance in the United States. This trap was modernized in the 1950s to the miniature CDC light trap, with the addition of CO2 following soon after. The incandescent light has the tendency to attract nontarget insects, as well as losing a substantial portion of their energy as heat. Few studies have delineated whether heat or light in isolation make a difference in field collections using the former traps within the United States. Our study focused on isolating heat and light variables by using incandescent bulbs, light emitting diode (LED) bulbs, and electric heating patches affixed to a base model CO2 trap as designed at the Salt Lake City Mosquito Abatement District. Sites were selected in the urban and suburban foothills and canyons of the Wasatch Mountain front, industrial areas near the Salt Lake City International Airport, and rural wetlands in the marshes outlying the Great Salt Lake. Five traps were replicated within each sector during the summer and fall summer seasons. Collections were composed of Aedes dorsalis (Meigen), Culex pipiens L., Culex tarsalis Coquillett, and Culiseta inornata (Williston). Composition changes were a result of seasonal, rather than spatial, shifts. The results showed that LED light traps depressed collections of key species. Otherwise, there were negligible differences in collections among incandescent, heat film, and base model traps. In the Intermountain West, the miniature CDC trap is reliable enough to make programmatic decisions even if light usage varies by district.

Partially Substituting Top-light with Intracanopy Light Increases Yield More at Higher LED Light Intensities

This study compared supplemental white light-emitting diode (LED) light provided on top of the canopy (top-light) or partially on top and partially as intracanopy light (ICL) in high-wire cucumber (Cucumis sativus) and tomato (Solanum lycopersicum) crops. The aim was to determine the effects of partially substituting top-light by ICL on fruit yield and its underlying yield components. For each crop, three replicate Venlo glasshouse compartments were used. Two cucumber (HiPower and Skyson) and two tomato cultivars (Brioso and Merlice) were planted in the second half of Oct 2020 and grown on stone wool for a period of 15 weeks (cucumber) or 20 weeks (tomato). Light was supplied at either a light intensity of 250 or 375 µmol⋅m−2⋅s−1, provided either as 100% top-light or as 67% (2/3) top-light and 33% (1/3) ICL. For cucumber at the higher light intensity, 50% more fruits were retained and for tomato at the higher light intensity, planting density was 50% higher to keep the plants balanced in terms of source-to-sink ratio. Substituting 33% of top-light with ICL resulted on average in an increase of 17% in fresh fruit yield for both cucumber and tomato. This increase was twice as high at the higher light intensity (20% to 24%) compared with the lower light intensity (10% to 12%). For both cucumber and tomato, the higher yield for ICL treatments resulted mainly from higher total plant dry weight, whereas partitioning to the fruits was hardly affected. For both crops, the higher plant dry weight resulted from a higher light use efficiency. Increasing light intensity from 250 to 375 µmol⋅m−2⋅s−1 resulted in 38% higher total daily light integral (including solar radiation) and 36% to 37% higher total plant dry weight in cucumber. In tomato, the higher light intensity resulted in 33% higher daily light integral and 36% to 40% total plant dry weight. These values are in agreement with the rule of thumb that 1% increment in light results in 1% increase in plant growth. For cucumber, partially substituting top-light by ICL as well as increasing light intensity resulted in longer and greener fruits, whereas tomato fruit quality (Brix, pH) was unaffected by ICL or light intensity. In conclusion, partially substituting top-light by intracanopy light increased fruit yield and this was even more so at higher than at lower supplemental light intensities.

The synthesis and properties of Ca3 Sc2 Si3 O12 :Ce3+ (CSSG) phosphor are utilized for the development of human-centric lighting light-emitting diodes (HCL-LEDs).

In this study, cerium ion (Ce3+ )-doped calcium scandium silicate garnet (Ca3 Sc2 Si3 O12 , abbreviated CSSG) phosphors were successfully synthesized using the sol-gel method. The crystal phase, morphology, and photoluminescence properties of the synthesized phosphors were thoroughly investigated. Under excitation by a blue light-emitting diode (LED) chip (450 nm), the CSSG phosphor displayed a wide emission spectrum spanning from green to yellow. Remarkably, the material exhibited exceptional thermal stability, with an emissivity ratio at 150°C to that at 25°C reaching approximately 85%. Additionally, the material showcased impressive optical performance when tested with a blue LED chip, including a color rendering index (CRI) exceeding 90, an R9 value surpassing 50, and a biological impact ratio (M/P) above 0.6. These noteworthy findings underscore the potential applications of CSSG as a white light-converting phosphor, particularly in the realm of human-centered lighting.

Illuminating the Future: Cost-Benefit Analysis of the Installation of LED Street Lights in Townships

Municipalities face decisions about maintaining and upgrading their streetlighting. Do they continue to replace bulbs in their existing lighting systems, or move to energy-efficient systems piecemeal or all at once? This research paper argues that the financial and environmental benefits of a complete shift to efficient Light Emitting Diode (LED) fixtures make the investment worthwhile. Analysis of data from Tredyffrin Township in southeastern Pennsylvania, that is currently making the switch to LED lighting systems, supports the conclusion that committing to one-time full replacement can maximize energy savings and that the issuance of green bonds, over standard municipal bonds, for financing is both viable and advantageous as it can lead to additional savings and budget surplus. Despite a higher initial investment, the extended lifespan of LED lights, compared with Mercury Vapor (MV) lamps, drastically lowers maintenance and replacement costs, leading to considerable long-term savings. By using green bonds, a financing instrument made available for environmentally beneficial projects, a municipality's financing costs can be kept low and large projects can be undertaken, for the fullest financial and environmental benefit.