Light Production Research Articles

Innovative Stacked Yellow and Blue Mini-LED Chip for White Lamp Applications.

This study introduces a novel approach for fabricating vertically stacked mini-LED arrays, integrating InGaN yellow and blue epitaxial layers with a stress buffer layer to enhance optoelectronic characteristics and structural stability. This method significantly simplifies the LED design by reducing the need for RGB configurations, thus lowering costs and system complexity. Employing vertical stacking integration technology, the design achieves high-density, efficient white light production suitable for multifunctional applications, including automotive lighting and outdoor signage. Experimental results demonstrate the exceptional performance of the stacked yellow and blue mini-LEDs in terms of luminous efficiency, wavelength precision, and thermal stability. The study also explores the performance of these LEDs under varying temperature conditions and their long-term reliability, indicating that InGaN-based yellow LEDs offer superior performance over traditional AlGaInP yellow LEDs, particularly in high-temperature environments. This technology promises significant advancements in the design and application of lighting systems, with potential implications for both automotive and general illumination markets.

Cascade effects of global supply chains induced by regional conflicts increase global inequality

Regional conflicts have become prominent in triggering shocks on supply chains and cascade effects on resource management. Reliable assessments of the cascading pattern of production resources among sectors globally are missing. Here, we modeled global multisectoral production losses and the cascading pattern of a grain supply shock in the Russia–Ukraine regional conflict by utilizing a geographic input–output approach. We find that the most cascading losses emerged in the textile (17.04 % ± 0.72 %, 95 % confidence intervals) and food-processing sectors (16.85 % ± 0.5 %). The shock propagated in a “grain–processed food/livestock” direct chain and a “light manufacturing–heavy manufacturing/textile” indirect chain. Prolonged conflict and disrupted resource allocation decreased the efficiency of production recovery in low-income countries and amplified inequality of production resources. Our approach presents a quantitative framework for unexpected supply chain shocks. The findings support the case for production aid to low-income countries and circular supply chains for sustainable development.

Market for light industry products: current changes and development trends

This article analyzes the current state of the light industry products market, its promising directions and development trends. Key market indicators, characterized by a decrease in demand in 2022, but an increase in the «average purchase amount» indicator, were identified. In addition, the role of the main trends (changes in the legislative framework and the transition to sustainable fashion) in facilitating the entry of new companies into the market is noted.

CEO reflections on leadership lessons from the global pandemic: back to basics during crisis

PurposeThe current study qualitatively examined the challenges and lessons learned from Chief Executive Officers (CEOs) during the COVID-19 pandemic. The current study draws upon previous crisis leadership research to understand and classify the most important lessons learned from CEOs.Design/methodology/approachA total of 30 in-depth, structured CEO interviews were conducted with large, multi-divisional organizations across market sectors that included healthcare, automotive, steel, agriculture, logistics, distribution, banking, financial services, light manufacturing and industrial services during the COVID-19 pandemic. Three separate judges performed a content analysis, and three main themes (eleven overall lessons) emerged related to high-level leadership lessons learned through the pandemic.FindingsThe leadership lessons that emerged overwhelmingly focused on the importance of emphasizing leadership fundamentals during crisis. CEO’s shared the importance of getting “back to basics” during the pandemic. The current study presents these leadership lessons, along with insights for leadership practices and development, as well as future research. Additionally, questions for reflection are posed to stimulate current and future leaders’ growth and development.Originality/valueThe COVID-19 pandemic has impacted leadership and organizations in an unprecedented manner. Previous research has outlined the leadership traits and behaviors needed to successfully lead through organizational crises. However, little research has examined CEO level lessons learned, focusing on learning from such crises.

Night-time light loss during the 2022 Kyiv offensive revealed through VIIRS DNB

ABSTRACT The satellite low-light imagers can detect changes in nighttime lights caused by ground military conflict. The Kyiv Offensive in Kyiv, Ukraine, which lasted less than 40 days during the Russia – Ukraine conflict, began on 24 February 2022. In addition to the monthly light product, we included a daily light product to analyse the number and average intensity of light pixels in the area around Kyiv over time. The changing trends of two parameters are similar. From February to March, the number of light pixels dropped by 65.2%, and average intensity by 24.5%. To account for daily fluctuations, the relative light ratio was introduced, comparing Kyiv to Moscow, Gomel, and Warsaw. This parameter showed a significant decrease in both the number and intensity of light pixels between days 411 and 423 since January 1, 2021, aligning with the conflict’s start. The relative light ratio revealed a 70.6%, 63.5%, and 57.3% drop in light pixel numbers, and a 9.5%, 24.2%, and 48.4% drop in their average intensity for the respective city pairs. However, unusual fluctuations in the reference cities, such as in Gomel during Christmas and in Moscow at the conflict’s onset, present some problems in using the relative light ratio.

Optimizing charge transport in hybrid GaN-PEDOT:PSS/PMMADevice for advanced application

Organic–inorganic hybrid light-emitting devices have garnered significant attention in the last few years due to their potential. These devices integrate the superior electron mobility of inorganic semiconductors with the remarkable optoelectronic characteristics of organic semiconductors. The inquiry focused on analyzing the optical and electrical properties of a light-emitting heterojunction that combines p-type GaN with organic materials (PEDOT, PSS, and PMMA). This heterojunction is an organic–inorganic hybrid. The procedure entailed utilizing a spin-coating technique to apply a layer of either poly(methyl methacrylate) (PMMA) or a mixture of PMMA and poly(3,4ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT: PSS) onto an indium tin oxide (ITO) substrate. Subsequently, different Nd:YAG laser pulses (200, 250, and 300 pulses) were used to administer a GaN inorganic layer onto the prepared organic layer using a pulsed laser deposition approach. Subsequently, the thermal evaporation technique was employed to deposit an aluminum electrode on the top of the organic and inorganic layers, while laser pulses were fine-tuned for optimal performance. The Hall effect investigation verifies the p-type conductivity of the GaN material. The electroluminescence studies confirmed the production of blue light by the GaN-based devices throughout a range of voltage situations, spanning from 45 to 72 V.

A Review of the Characteristics of Light Pollution: Assessment Technique, Policy, and Legislation

Light pollution from the use of artificial lighting poses significant impacts on human health, traffic safety, ecological environment, astronomy, and energy use. The advancement of characteristics of light pollution assessment technology has played a significant role in shaping prevention and control policies, thereby enabling measures, such as environmental standards and legislation and product procurement guidelines, but considerable variation in the definition, control strategies, and regulatory frameworks remains. Therefore, there is a need to review the characteristics of light pollution, including the assessment technique, policy, and legislation. Through the literature review, it can be found that technical standards are required to prevent light pollution. For example, light pollution is decreased by 6% in France through the legislation of artificial light. Key approaches are suggested to control global light pollution, including implementing ambient brightness zoning, regulating lighting product usage, and establishing dark sky reserves. Technology and policy should be integrated. The precise data coming from satellite imagery, drones, and balloons could provide guidance when making the policies.

Cs2MnCl4:Eu2+: A Near-Violet Light-Triggered Single-Component White Light Emitter.

Single-component white-light luminescent materials are considered an economical and facile choice for phosphor-converted white light-emitting diodes (pc-WLEDs). Here, a new single-component white-light-emitting material Cs2MnCl4:Eu2+ based on the combination of a lead-free halide structure and a rare-earth ion is first reported. Benefiting from the smart dilution-sensitization design strategy, white light composed of dual broad emission originating from Eu2+ (blue light, 444 nm, 4f65d1 → 4f7) and Mn2+ (yellow light, 566 nm, 4T1g → 6A1g) was successfully realized under near-ultraviolet light (404 nm) radiation with a high photoluminescence quantum yield of 66%. Based on the single-source Cs2MnCl4:Eu2+ phosphor, a pc-WLEDs device with "eye-friendly" white light production was successfully fabricated. The pc-WLEDs exhibit suitable color coordinates of (0.3294, 0.2746) and a high color rendering index of 82.3, demonstrating the potential in the future health-conscious illumination application by reducing the risk of eye strain and high-energy blue-light damage. This work achieves a new single-component white-light-emitting Mn-based halide phosphor and provides a new path for the design of single-component white light sources in Mn-based halides.

Improvement of Climate Resource Utilization in the Southwestern Hilly Region through the Construction of a New Multi-Maturing Cropping System

The construction of an appropriate cropping pattern is crucial for the improvement of regional agricultural economic efficiency and sustainable development. Despite previous efforts, there remains a gap in optimizing cropping patterns that fully leverage climate resources to enhance production efficiency. This study addresses this gap by systematically comparing the differences in climate resource allocation, production efficiency and crop response among models by constructing four new triple-maturing cropping models at typical ecological sites in the hilly areas of southwest China. To solve the above problems, we constructed eight cropping patterns and classified them to three as follows: the Traditional Double Cropping System, the Traditional Triple Cropping System, the Novel Triple Cropping System. The results showed that the new multi-maturing planting pattern was significantly better than the traditional two-maturing netting pattern and the traditional three-maturing planting pattern in terms of light, temperature and water productivity. Compared with the traditional two-maturity net cropping model and the traditional three-maturity cropping model, the new cropping model increased light energy productivity by 97.88% and 50.00%, respectively; light energy use by an average of 0.48% and 0.31%; cumulative temperature productivity by an average of 84.70% and 49.14%; and rainfall productivity by an average of 101.04% and 49.61%. An assessment of the light, temperature and water meteorological resource use efficiency of the different treatments showed that the resource use efficiency of the new multi-maturing planting pattern was on average 111.58% and 74.78% higher than that of the traditional two-maturing net planting pattern and the traditional three-maturing planting pattern, with the T6 pattern having the highest resource use efficiency. The new multi-ripening cropping pattern has demonstrated production stability in response to changes in light, temperature and water resources, better adapting to weekly climate changes, stabilizing yields and improving efficiency. In summary, the results of this study can provide a theoretical basis for optimizing cropping patterns and promoting the use of climate resources in agriculture and sustainable development. Future research should focus on further refining these models, exploring their adaptability to various climatic conditions, and evaluating their long-term economic and environmental impacts.

The Macroalga Kappaphycus alvarezii as a Potential Raw Material for Fermentation Processes within the Biorefinery Concept: Challenges and Perspectives

Seaweed is a fast-growing biomass source that is currently studied as feedstock for sustainable industrial production in a wide variety of markets. Being composed mostly of polysaccharides, macroalgae can be integrated in biorefineries for obtaining bioproducts via fermentation. Kappaphycus alvarezii has been introduced experimentally to Brazil’s south coastline in 1995 and is now cultivated on a large scale to keep up with the high carrageenan demand in various industrial sectors. In this review article, an introduction is given on renewable biomass and environmental issues, focusing especially on third-generation biomass and its promising features and use advantages. Later on, the processing of K. alvarezii for the use of its saccharide portion for fermentative processes is approached. The current state of research conducted alongside challenges and hurdles in K. alvarezii hydrolysate fermentation processes provides insight into future studies needed to make new fermentation processes viable. Next, some fermentation products are discussed, and the metabolism of galactose in microorganisms is also presented to bring to light other possible fermentation products that are not yet, but can be, obtained from K. alvarezii. Finally, a simple and comprehensive scheme for K. alvarezii fermentation biorefinery is presented to demonstrate a generic example for a possible configuration for obtaining valuable bio-products. In the literature, production of ethanol and lactic acid were already reported from K. alvarezii. This review aims to help envision new industrial processes that can be developed for this most valuable macroalga.

Simulation analysis of micro-explosion during emulsification feeding of residue fluidized catalytic cracking

Residue Fluidized Catalytic Cracking (RFCC) is one of the key processes to convert heavy oil into light products in refineries. The fast and sufficient vaporization of the feedstock in the FCC riser reactor can promote the catalytic cracking reaction and is beneficial for increasing the yield of light products and decreasing the yield of coke. However, fast vaporization of residue oil is extremely challenging due to its high density and viscosity. Recently, emulsified feeding technology is seen as a potential method that can effectively enhance the vaporization of RFCC feedstock. Computational Fluid Dynamics (CFD) simulations were performed in order to reveal the micro-explosion mechanism of emulsion droplet in the riser reactor. The CFD model was validated against experimental results from literature. The model was used to study micro-explosion of emulsified droplets in the gas phase and at the catalyst particle surface separately. It was found that due to the micro-explosion of emulsion oil droplets in producing large number of tiny droplets, the secondary atomization of droplets can be realized. In the gas phase, the interfacial area of emulsion droplet can be improved by 5 to 15 times. At the catalyst surface, the percentage of liquid film coverage was reduced by 32.6 %, and the droplet diameter was reduced by 92 % for the emulsified feeding technology. These results indicate that the vaporization efficiency of the residual oil can be greatly improved by this technology.

High throughput screening of promoted bimetallic catalysts supported on alumina for production of light olefins via Fischer-Tropsch synthesis with artificial neural network and response surface methodology

The production of light olefins via Fischer-Tropsch Synthesis (FTS) was investigated by both experimental and modeling studies. Experimental studies were conducted by employing promoted FeCo/α-Al2O3 (FeCo) bimetallic catalysts. The Response Surface Methodology (RSM) and Artificial Neural Network (ANN) methods were used in modeling. Specifically, effects of the types and concentration of promoters on the catalytic performances of α-Al2O3 supported iron-cobalt bimetallic catalysts are investigated by using Ce, Ni, La, Ho, Ga Cu, Mn, and Zn used as promoters. A total of 49 catalysts were prepared by co-impregnation method and tested at 310 °C and 1 bar in a high-speed catalyst performance test system (HT-CPA). The FTS performances of catalysts showed that both the types and amounts of the promoters can affect light olefin production. The light olefin (C2=–C3=) production of unpromoted FeCo catalyst was about 3.87 × 10−3 (mol C/g active metal. h). The best performances were obtained from FeCo catalysts promoted with Ho, Cu, and Zn. Presence of these promoters increased olefin production up to ∼ 84 %, 76 % and 70 %, respectively.Performance parameters (MSE and R2) of RSM and ANN models revealed that both methods can be used to support experimental studies and provide a procedure for optimizing catalyst formulations yielding the desired product selectivity in FTS processes. The RSM outcomes aligned with experimental findings, suggest that that Ho, Cu, and Zn can serve as suitable promoters for the light olefin production in FTS. ANN model attained higher performance parameters (R2 = 0.95 and MSE = 2E−7) than RSM model (R2 = 0.85 and MSE = 3.4E−7). This indicates that ANN model, which designed as one hidden layer including 7 neurons, can provide better predictions and a fitting capacity. Therefore, it may be used in further optimization and sensitivity analysis approaches. Alignment degree between the experimental and modeling results demonstrates that the proposed methodology can provide a reliable and efficient way to guide experiments to optimize catalyst formulations through identification of potential promoters and their amounts to be used.

Identifying the Central Business Districts of global megacities using nighttime light remote sensing data

ABSTRACT The Central Business Districts (CBDs) are important hubs for urban economic activities. In the context of globalization, a unified CBD boundary would greatly facilitate the study of global CBD comparative analysis, urban socio-economic development, urban transport and commuting mode. However, previous studies have encountered challenges in developing a practical method for global CBD identification due to limitations in data sources and methodologies. In this study, we selected 32 global megacities as research objects and used the open-access Black Marble nighttime light (NTL) products to construct indicators with the intensity and angular effects of NTL. Clustering and decision tree were then employed to derive rules for CBD identification. Results show that combining Z-score indicators and the strategy of clustering 32 cities before decision tree classification could improve the accuracy of CBD identification, which achieved a producer accuracy of 85%. The 32 cities were clustered into three types, i.e. U.S.A.-like, the mixed type, and China-like. The rules for CBD identification became more complex in the above order, but the accuracy decreased in turn. This study provides a new CBD identification method for cities lacking reference data, allowing for the delineation of unified and comparable CBD boundaries on a large scale.

Exploring textual–visual strategies in internet-based light food advertising: a study of Taobao advertisements in China

Amidst global health concerns such as COVID-19 and rising obesity rates, the connection between food choices, societal well-being, and cultural shifts has gained attention. In China, the rise of “light food” consumption on platforms like Taobao reflects a growing trend towards health-conscious dietary preferences. With a dataset comprising 633 images and 45,817 words, condensed into 50 images for analysis, this research aims to understand how these advertisements influence perceptions of healthiness and desirability, and whether there is a discrepancy between advertised health benefits and actual nutritional content. This study delves into the advertising strategies employed for light food products on the Taobao platform in China, utilizing a Textual–Visual Thematic Analysis (TVTA) framework. Noteworthy findings include: (1) Internet-based light food advertising adopts a dual textual and visual approach. (2) Identification of prevalent multimodal devices, such as medium shots, varied camera angles, vibrant colors, and large size. (3) Uncovering inconsistencies in presentation that may pose potential consumer misperceptions. These discoveries underscore the nuanced landscape of light food advertising, offering valuable insights for both academia and industry.

Development of a superconducting undulator cryostat based on the thermosiphon effect

As a specific device for light production, undulators have been researched and developed since the third generation of synchrotron photon sources. Nowadays, superconducting undulators become a research hotspot. However, the cryostat, which is used to create a liquid helium temperature environment, often causes the failure of the superconducting undulator. In this paper, a cryostat for a superconducting undulator is designed and investigated. First, a new refrigeration distribution is proposed that can provide more excess cooling capacity at 4.2 K temperature. For the cooling of the superconducting magnet, a liquid helium circulation loop based on the thermosiphon effect is designed, which has no pump or any other moving parts. Next, based on high-temperature superconducting technology, six binary current leads are used to decrease the heat load. The beam chamber is cooled below 20 K to reduce possible effect on the magnet. In addition, for the tubes that connect the 4.2 K helium tank to the room temperature component, the thermoacoustic oscillation is studied. In the experiment, the superconducting magnet could be cooled and maintained at 4.2 K depending on the thermosiphon loop. No helium was discharged when the magnet went through a quench which generated large heat in a short time. There was no liquid helium consumption and the excess cooling capacity reached 2.2 W. The maximum magnet current is as high as 470 A. This study can provide a valuable reference for the development of superconducting undulator cryostats.

The language of light: a review of bioluminescence in deep-sea decapod shrimps.

In the dark, expansive habitat of the deep sea, the production of light through bioluminescence is commonly used among a wide range of taxa. In decapod crustaceans, bioluminescence is only known in shrimps (Dendrobranchiata and Caridea) and may occur in different modes, including luminous secretions that are used to deter predators and/or from specialised light organs called photophores that function by providing camouflage against downwelling light. Photophores exhibit an extensive amount of morphological variation across decapod families: they may be internal (of hepatic origin) or embedded in surface tissues (dermal), and may possess an external lens, suggesting independent origins and multiple functions. Within Dendrobranchiata, we report bioluminescence in Sergestidae, Aristeidae, and Solenoceridae, and speculate that it may also be found in Acetidae, Luciferidae, Sicyonellidae, Benthesicymidae, and Penaeidae. Within Caridea, we report bioluminescence in Acanthephyridae, Oplophoridae, Pandalidae, and new observations for Pasiphaeidae. This comprehensive review includes historic taxonomic literature and recent studies investigating bioluminescence in all midwater and deep benthic shrimp families. Overall, we report known or suspected bioluminescence in 157 species across 12 families of decapod shrimps, increasing previous records of bioluminescent species by 65%. Mounting evidence from personal observations and the literature allow us to speculate the presence of light organs in several families thought to lack bioluminescence, making this phenomenon much more common than previously reported. We provide a detailed discussion of light organ morphology and function within each group and indicate future directions that will contribute to a better understanding of how deep-sea decapods use the language of light.

Lighting the way: how the Vibrio fischeri model microbe reveals the complexity of Earth's "simplest" life forms.

Vibrio (Aliivibrio) fischeri's initial rise to fame derived from its alluring production of blue-green light. Subsequent studies to probe the mechanisms underlying this bioluminescence helped the field discover the phenomenon now known as quorum sensing. Orthologs of quorum-sensing regulators (i.e., LuxR and LuxI) originally identified in V. fischeri were subsequently uncovered in a plethora of bacterial species, and analogous pathways were found in yet others. Over the past three decades, the study of this microbe has greatly expanded to probe the unique role of V. fischeri as the exclusive symbiont of the light organ of the Hawaiian bobtail squid, Euprymna scolopes. Buoyed by this optically amenable host and by persistent and insightful researchers who have applied novel and cross-disciplinary approaches, V. fischeri has developed into a robust model for microbe-host associations. It has contributed to our understanding of how bacteria experience and respond to specific, often fluxing environmental conditions and the mechanisms by which bacteria impact the development of their host. It has also deepened our understanding of numerous microbial processes such as motility and chemotaxis, biofilm formation and dispersal, and bacterial competition, and of the relevance of specific bacterial genes in the context of colonizing an animal host. Parallels in these processes between this symbiont and bacteria studied as pathogens are readily apparent, demonstrating functional conservation across diverse associations and permitting a reinterpretation of "pathogenesis." Collectively, these advances built a foundation for microbiome studies and have positioned V. fischeri to continue to expand the frontiers of our understanding of the microbial world inside animals.

Light Environment Analysis and Production of Red Leaf Lettuce in Greenhouses with Flexible Solar Cells

Light Environment Analysis and Production of Red Leaf Lettuce in Greenhouses with Flexible Solar Cells

Interface interaction mediated surface plasmon resonance enhancement promoted visible-light-driven CO2 reduction with water

The conversion of carbon dioxide (CO2) into fuel using solar energy holds significant promise. However, the inefficient use of light and poor production activity have hindered its development. Here, we propose a simple in situ annealing oxidation method by coating a layer of TiO2 outside TiN, a material with a favorable price and localized surface plasmon resonance (LSPR) effect, to create an L-TiNO composite. The yield of CO over L-TiNO (50.8 μmol g−1 h−1) is 56.4 times that over TiO2 (0.9 μmol g−1 h−1) under visible light irradiation in pure aqueous environment, with a selectivity of 95.98%. In-situ Fourier transform infrared (FTIR) measurements reflect the CO2-COOH*-CO conversion route happening on L-TiNO. Characterizations like the Kelvin probe force microscopy (KPFM) technique confirm the generation of built-in electric field, which facilitates efficient carrier separation and migration. Density functional theory (DFT) calculations support that L-TiNO with LSPR effect alters the shape of absorbed CO2 to facilitate generation COOH* via forming hydroxyl end group (Ti-OH) and promotes CO* desorption to CO(g). This work provides valuable insights into the coupling of plasmonic materials with semiconductors to achieve efficient solar energy utilization.

Role of municipal solid waste incineration fly ash components in co-pyrolysis of oily sludge: Pyrolysis products and catalytic mechanism

The co-pyrolysis of oily sludge (OS) and municipal solid waste incineration fly ash (IFA) is a promising strategy for sustainable waste management. This study delves into the distinct catalytic roles of individual IFA components during co-pyrolysis and assesses their impact on the inherent Fe species in OS, highlighting their contributions to overall catalytic activity. Notably, in comparison to IFA, CaCl2 and KCl significantly enhance pyrolysis oil upcycling, while IFA components collectively exhibit a positive catalytic effect on pyrolysis gas and coke production. Ca(OH)2 notably boosts H2 yield by 137.16 %. Alkali chlorides facilitate gaseous hydrocarbon formation and convert oxygen-containing compounds to CO and CO2 which are subsequently consumed and absorbed by CaO and Ca(OH)2. CaCl2 and KCl promote heavy compound decomposition and alkane aromatization, reducing coke formation and increasing light aromatic production. Conversely, NaCl increases alkane proportions. However, CaSO4 and CaCO3 hinder catalytic reactions, promoting carbon conversion to coke. Importantly, IFA compounds aid the dispersion of inherent Fe-based species from OS on char surface, enhancing in-situ catalytic pyrolysis. Additionally, the augmented H2 production accelerates the reduction of Fe-based species. The findings expand waste utilization possibilities and provide insights for co-processing solid wastes.