Light Supply Research Articles

Influence of Light Intensity and Temperature on the Development of Early Life Stages of Ascophyllum nodosum (Phaeophyceae)

Ascophyllum nodosum is an ecologically and economically important species forming marine forests in temperate regions. In Europe, this brown seaweed reaches its southern distribution limit in the north of Portugal, where populations are under climatic pressure. Conservation and restoration actions are essential to preserve the important ecological roles of these populations, including biodiversity enhancement. In this study, we assessed the effect of temperature and light on the development of the early life stages of A. nodosum, from gamete germination and rhizoid development to germling growth, in order to support the establishment of nursery protocols for producing seedlings that can be used in reforestation actions. We found that for this population, temperature around 12 °C and low-light conditions (40 μmol m−2 s−1) favor gamete germination, rhizoid development, and initial germling growth during the first month, after which higher light supply (>80 μmol m−2 s−1) is needed to sustain further growth stages. The results obtained in this study are relevant for the establishment of nursery methods for A. nodosum and should be complemented by further studies to determine more precisely the light and nutrient requirements to optimize growth in the germlings’ later growth stages.

Comparative leaf anatomy of two species of Ipomoea L. (Convolvulaceae): taxonomic importance and adaptations to xeric conditions of the cangas.

Accurate species identification is the first step towards establishing conservation strategies, especially regarding rare and threatened species, such as those studied here. Moreover, understanding the responses to the environment and growing conditions of endemic species is necessary for its conservation. This study compares the leaf anatomy of Ipomoea cavalcantei and I. marabaensis, which grow on the Brazilian ironstone outcrops (cangas) and exhibit morphological convergence. Leaf anatomical characters of the species were described. Additionally, the leaf adaptive potential of I. cavalcantei was evaluated, comparing individuals grown in natural canga areas (in situ) and cultivated in topsoil (ex situ). Quantitative analysis evaluated stomatal density, polar and equatorial diameter of stomata, and thickness of the epidermis and mesophyll. Ipomoea cavalcantei and I. marabaensis can be distinguished by the mesophyll type. Ipomoea marabaensis is also characterized by the presence of lateral protuberances on the abaxial surface of the midrib. Individuals of I. cavalcantei under cultivation have lower stomatal density, although their functionality (polar/equatorial diameter) is more significant than those grown in a natural environment; these individuals also exhibit leaves with a thinner cuticle, abaxial epidermal cells with more sinuous walls, a lower occurrence of trichomes and secretory cells (laticifers), and more druse-containing idioblasts in the mesophyll. All these traits are adaptations to growing conditions that include lower light and the absence of water stress. Leaf anatomical traits showed to be useful to delimit Ipomoea cavalcantei and I. marabaensis in the non-reproductive stage. For individuals of I. cavalcantei cultivated in topsoil, some features, especially of the epidermis, respond to light and water supply.

Rapid osmocontractile response of motor cells of Mimosa pudica pulvini induced by short light signals.

The Mimosa pudica leaf has motor organs allowing movements driven by cell osmotic changes in the parenchyma cells in response to various stimuli. Short white light pulses induce rapid and large seismonastic-like movements (denoted "photostimulation") of the primary pulvini in various leaves within 120 s after the onset of light. An early event recorded is a wavelength-related modification of the plasma membrane difference: potential depolarization under white, blue, green, and red wavelengths, and hyperpolarization under far red wavelengths (and also in darkness). The photoreactivity of the pulvini is controlled by a circadian rhythm and modulated by the applied diurnal photoperiod cycle (photophase ranging from 6 to 18 h). The reactivity varied among plants and even between leaves on the same plant. The level of reactivity is related to the photon fluence rate in the range from 10 to 140 μmol m-2 s-1 under white light and to the experimental temperature in the range 15°C-35°C. An "accommodation" to light supply is evidenced by a modulation of the reactivity in relation to the schedule of light application under low fluence rates and the introduction of short darkness intervals during the first 30-s light pulse. The blue light-induced photostimulation is under phytochrome control.

Effects of CO2 Aeration and Light Supply on the Growth and Lipid Production of a Locally Isolated Microalga, Chlorella variabilis RSM09

The Chlorophyceae algae, specifically Chlorella spp., have been extensively researched for biodiesel production. This study focused on the alga Chlorella variabilis RSM09, which was isolated from a brackish-water environment at Raksamae Bridge in Klaeng District, Rayong Province, Thailand. The effects of the carbon dioxide gas (CO2) concentration (0.03%, 10%, 20%, 30%, 40%, and 50% v/v), light intensity (3000, 5000, and 7000 Lux), and photoperiod (12:12, 18:6, and 24:0 h L/D) on algal growth and lipid production were investigated. The results indicated that C. variabilis RSM09 achieved optimal growth under 20% v/v CO2 aeration, with an optical density of approximately 2.91 ± 0.27, a biomass concentration of 1.32 ± 0.14 g/L, and a lipid content of 21.96 ± 0.29% (wt.). Among the three different light intensities, higher optical density (4.20 ± 0.14), biomass (1.79 ± 0.25 g/L), and lipid content (20.75 ± 2.0% wt.) were at the 5000 Lux of light intensity. Additionally, the photoperiod of 24:0 h (L/D) produced the highest biomass at 1.86 ± 0.21 g/L, followed by the 18:6 h light/dark photoperiod with a biomass of 1.65 ± 0.17 g/L, and the 12:12 h light/dark photoperiod with 1.35 ± 0.43 g/L. In contrast, the 18:6 h L/D photoperiod yielded a higher lipid concentration of 25.22 ± 2.06% (wt.) compared to the others. All cultured microalgae showed significant effects on fatty acid composition. Palmitic (16:0), linoleic (C18:2), and linolenic (C18:3) acids were predominant in C. variabilis RSM09 under all photoperiods. This study exhibited that the microalga C. variabilis RSM09 has great potential as a feedstock for biodiesel production.

Distinct responses of diatom- and flagellate-dominated Antarctic phytoplankton communities to altered iron and light supply

Primary production in the Southern Ocean is strongly influenced by the availability of light and iron (Fe). To examine the response of two distinct natural Antarctic phytoplankton communities (diatom vs. flagellates) to increasing light and Fe availability, we conducted two shipboard incubation experiments during late summer and exposed each community to increasing light intensities (30, 80, and 150 µmol photons m−2 s−1) with or without Fe amendment. Our results show clearly that both communities were Fe-limited since Fe addition resulted in higher particulate organic carbon (POC) production rates. The magnitude of the Fe-dependent increase in POC production, however, varied between the two stations being higher in the diatom-dominated community relative to the flagellate-dominated community. This differential response to increasing Fe supply could be attributed to the higher Fe requirement of the flagellate-dominated assemblage relative to the diatom-dominated assemblage. Irrespective of Fe availability, light also strongly stimulated the POC production of both communities between low and medium light supply (30 versus 80 µmol photons m−2 s−1), indicating that both assemblages were light-limited in situ. However, since POC production of both communities did not increase further at the highest light intensity (150 µmol photons m−2 s−1) even under high Fe supply, this suggests that light supply was saturated or that other conditions must be fulfilled (e.g., availability of trace metals other than Fe) in order for the communities to benefit from the higher light and Fe conditions.

An Innovative Water Splitting Process for a Sustainable In Situ Hydrogen Generation–Reduction of Nitrobenzenes Catalyzed by a New Bimetallic Nanocatalyst

ABSTRACTIn this research, bimetallic CdNi nanoparticles encapsulated in a magnetic spent coffee ground (Fe3O4@COFF/CdNi) was synthesized as a new nanocatalyst. The structural and chemical characteristics of Fe3O4@COFF/CdNi were comprehensively investigated using various techniques, including FT‐IR, XRD, XPS, TEM, VSM, EDS, TGA, BET, and ICP. Through XRD, XPS analysis, TEM images, and EDS mapping, the presence of CdNi nanoalloys was conclusively established. Fe3O4@COFF/CdNi exhibited remarkable catalytic activity for the hydrogen generation from water using iso‐propanol as a clean sacrificial agent. The high catalytic performance of Fe3O4@COFF/CdNi was attributed to the synergistic cooperative effect of Cd and Ni within CdNi nanoalloys. Interestingly, this process was performed for the in situ generated hydrogen from water to reduce a range of nitrobenzenes simultaneously into the corresponding anilines in high yields (93%–98%). The magnetic and hydrophilic characteristics of Fe3O4@COFF/CdNi facilitated its reusability over five runs. Using water as the most abundant hydrogen source, for the first time for in situ hydrogen generation–reduction of nitrobenzenes without demanding on external light sources or power supplies can be mentioned as a significant milestone of this field of study.

Light energy harvested flexible wireless sensing for disinfection sterilization in food storage

Cold chain logistics involves all aspects of food storage, transport, and sales. This study focuses on innovating cold storage disinfection within this context. Regular disinfection reduces microorganism growth, improves food quality, and ensures safety. Traditional methods lack automation, accurate monitoring, and responsive control. Conventional sensors are unsuitable for curved bottles and need frequent power changes. This paper proposes a light energy harvested flexible wireless sensing for disinfection sterilization in food storage (FLWDS). FLWDS comprises five parts: light energy harvesting and power supply node (LEPN), sensing node, control node, monitoring node, and host computer. A predictive control model improves response speed and accuracy. Bluetooth technology ensures real-time communication between nodes. FLWDS collects light energy inside the cold store as a supplementary energy source and can be used in curved structures with a response time of less than 1 s. The maximum communication distance is 40 m. The flexible level sensing system can be designed according to the induction pad’s length, with a measurement accuracy of 0.3 mm, sampling every 4.8 ms, and a resolution of 0.2 mm. FLWDS provides self-powered flexible wireless sensing, ensuring accurate liquid level measurement, improved food quality, reduced pollution, and increased sustainability.

Migrating ripples create streambed heterogeneity altering microbial diversity and metabolic activity

AbstractSandy sediments of lowland streams are typically transported at low flow in the form of migrating ripples. In these bedforms, microbial communities spanning all trophic guilds (heterotrophic bacteria, fungi, photoautotrophic and phagotrophic protists) are exposed to highly frequent moving–resting cycles of sediment grains. Up to date, it is unknown to what extent ripple migration impacts community metabolism and composition as well as the vertical zonation of sediment‐associated multitrophic microbial communities compared to stationary sediments. We hypothesize that, as a result of mechanical abrasion and limited light supply, migrating ripple sediments have lower microbial abundance, diversity, metabolism and resource acquisition and no vertical zonation compared to stationary sediments. We collected samples from five lowland streams in north‐eastern Germany between May and June 2020. The coarser and better sorted sediments of migrating ripples had a higher oxygen concentration and less organic matter than stationary sediments. Photosynthetic pigments, potential extracellular enzyme activities, bacterial cell counts, and fungal gene copies were lower in migrating ripples than in stationary sediments. In contrast, cell‐specific bacterial production was higher in migrating ripples. Metabarcoding revealed that bedform migration was important in shaping the community structure of bacteria, fungi, and phagotrophic protists. Dry mass‐related net community production, respiration, and bacterial production were higher in superficial compared to underlying layers irrespective of sediment transport. By modulating the abundance, diversity, and structure of different trophic guilds of microbial communities and their resource acquisition, migrating bedforms create streambed heterogeneity, shaping regional biodiversity and the flow of matter through the benthic food web.

The regulation of photosynthesis and growth of rapeseed seedling by the interaction of red and yellow lights with blue light

The interactive regulation among different lights on plant life-activities has not yet been fully understood. In the study, we investigated the interaction of red light (R) and yellow light (Y) with blue light (B) on growth and photosynthesis of rapeseed seedlings. The results showed Y and R as well as their combination of RY were not beneficial for plant photosynthesis and growth, but a quarter addition of B (RB, YB and RBY) obviously reversed these negative effects, improving stomatal behavior, leaf and root developments, photosynthetic traits, as well as synthesis and transport of photosynthetic products. Available light energy and B intervention together decreased the ratio of chlorophyll b (Chl b) to carotenoid (Car), while the opposite effect was observed in the absence of B treatments. Among the various lights, RY and Y significantly upregulated the majority of genes associated with chlorophyll metabolism, while RB predominantly upregulated genes related to the two photosystems (PS). Conversely, B and YB treatments generally suppressed the expression of these genes. Despite these differences in gene expression, the ratios of PSI/PSII to Chl b/Car were consistently maintained around 0.56 in the RB, YB, and RBY treatments. In contrast, this ratio was higher at 0.64 in the B treatment and lower, at less than 0.44, in the R, Y, and RY treatments. These ratios reflect the balance between light supply and utilization in plants under different lights, where plants under RB, YB, and RBY might achieve optimal light environments, while plants under B and under R, Y, and RY experienced high and low light stress, respectively. In conclusion, all combinations of B with R, Y or RY can be used for rapeseed cultivation, and the ratio of Chl b/Car to PSI/PSII might be an important reference index to select optimal light combinations for crop production.

Preliminary studies of selected Lemna species on the oxygen production potential in relation to some ecological factors.

Dissolved oxygen is fundamental for chemical and biochemical processes occurring in natural waters and critical for the life of aquatic organisms. Many organisms are responsible for altering organic matter and oxygen transfers across ecosystem or habitat boundaries and, thus, engineering the oxygen balance of the system. Due to such Lemna features as small size, simple structure, vegetative reproduction and rapid growth, as well as frequent mass occurrence in the form of thick mats, they make them very effective in oxygenating water. The research was undertaken to assess the impact of various species of duckweed (L. minor and L. trisulca) on dissolved oxygen content and detritus production in water and the role of ecological factors (light, atmospheric pressure, conductivity, and temperature) in this process. For this purpose, experiments were carried out with combinations of L. minor and L. trisulca. On this basis, the content of oxygen dissolved in water was determined depending on the growth of duckweed. Linear regression models were developed to assess the dynamics of changes in oxygen content and, consequently, organic matter produced by the Lemna. The research showed that the presence of L. trisulca causes an increase in dissolved oxygen content in water. It was also shown that an increase in atmospheric pressure had a positive effect on the ability of duckweed to produce oxygen, regardless of its type. The negative correlation between conductivity and water oxygenation, obtained in conditions of limited light access, allows us to assume that higher water conductivity limits oxygen production by all combinations of duckweeds when the light supply is low. Based on the developed models, it was shown that the highest increase in organic matter would be observed in the case of mixed duckweed and the lowest in the presence of the L. minor species, regardless of light conditions. Moreover, it was shown that pleustophytes have different heat capacities, and L. trisulca has the highest ability to accumulate heat in water for the tested duckweed combinations. The provided knowledge may help determine the good habitat conditions of duckweed, indicating its role in purifying water reservoirs as an effect of producing organic matter and shaping oxygen conditions with the participation of various Lemna species.

Phytoplankton stoichiometry along the salinity gradient under limited nutrient and light supply.

Ongoing climate warming alters precipitation and water column stability, leading to salinity and nutrient supply changes in the euphotic zone of many coastal ecosystems and semi-enclosed seas. Changing salinity and nutrient conditions affect phytoplankton physiology by altering elemental ratios of carbon (C), nitrogen (N) and phosphorus (P). This study aimed to understand how salinity stress and resource acquisition affect phytoplankton stoichiometry. We incubated a phytoplankton polyculture composed of 10 species under different light, inorganic nutrient ratio and salinity levels. At the end of the incubation period, we measured particulate elemental composition (C, N and P), chlorophyll a and species abundances. The phytoplankton polyculture, dominated by Phaeodactylum tricornutum, accumulated more particulate organic carbon (POC) with increasing salinity. The low POC and low particulate C:N and C:P ratios toward 0psu suggest that the hypoosmotic conditions highly affected primary production. The relative abundance of different species varied with salinity, and some species grew faster under low nutrient supply. Still, the dominant diatom regulated the overall POC of the polyculture, following the classic concept of the foundation species.

Study on the Effects of Different Light Supply Modes on the Development and Extracellular Enzyme Activity of Ganoderma lucidum

Edible fungi have certain photo-sensitivity during the mushroom emergence stage, but there have been few relevant studies on the responses of Ganoderma lucidum to different light irradiation conditions. Ganoderma lucidum were planted in an environmentally controllable mushroom room with different light supply modes that were, respectively, continuous white light (CK), red light (R), green light (G), blue light (B), and intermittent red light (R-), green light (G-), and blue light (B-), with a total light intensity of 15 μmol·m−2·s−1 and a light/dark (L/D) period of 12 h/12 h for each treatment. The interval in intermittent light treatments was 30 min. The optimal light supply mode suitable for the growth of Ganoderma lucidum was explored by analyzing the characteristics, nutritional quality, and extracellular enzyme activity in mushrooms exposed to different light treatments. The results showed that red light (whether in continuous or intermittent supply modes) inhibited the fruiting body differentiation of Ganoderma lucidum, showing delayed differentiation or complete undifferentiation. The highest stipe length and pileus diameter of fruiting bodies were detected under G- treatment, which were, respectively, increased by 71.3% and 3.2% relative to the control. The highest weight of fruiting bodies was detected under G treatment, which was significantly increased by 21.4% compared to the control (p < 0.05). Intermittent light mode seemed to be more conducive to the size development of the fruiting body, while continuous light mode was beneficial for increasing the weight. The highest contents of crude protein and total triterpenes in pileus were detected under G treatment (significantly 14.9% and 28.1% higher than the control, respectively), while that of the crude polysaccharide was detected under G- treatment (significantly 35.7% higher than the control) (p < 0.05). The highest activities of extracellular enzymes such as cellulase, hemicellulase, laccase, lignin peroxidase, and amylase were detected in fruiting bodies subjected to G treatment, which were significantly increased by 11.9%~30.7% in the pileus and 9.5%~44.5% in the stipe. Green light might increase the weight and nutrient accumulation in the pileus of Ganoderma lucidum via up-regulating the extracellular enzyme activities. This study provides an effective light supply strategy for regulating the light environment in the industrial production of Ganoderma lucidum.

The Work of Craft in the Age of Mechanical Reproduction: The Lai Xá Photography Village in Vietnam

In Lai Xá Village, Vietnam, studio photography is the village handicraft. Counter to Walter Benjamin’s characterization of the click of a button, privileging eye over hand, but typical of many craft traditions, photographers there describe painstaking apprenticeships through which they learned to master the tools and materials of their craft. They learned to compensate for the shifting properties of light, climate, humidity, and irregular supplies of electricity, chemicals and printing paper, and adapted to changing regimes of technique and labor organization. As in many other craft traditions, apprentices often acquired their most valuable knowledge by stealth. We argue that studio photography belongs within contemporary discussions of craft as a handed, adaptive, engaged, small-scale social practice, and that craft awareness enables a richer ethnographic understanding of the work of studio photographers, both material and social.

Fully optically controlled Li-ion-mediated artificial vision reflection arc system

Artificial vision systems have been extensively reported for processing unstructured data, performing pattern recognition, and performing visual simulations. Photonic synapses have become the core of most artificial vision systems due to their advantages such as low energy consumption and ultra-fast signal transmission. However, their integration is difficult, the integration difficulty of photon synapses is higher than that of crossbar arrays. Moreover, due to the hybrid drive of light and external power supply, low energy consumption and weight update under full optical control cannot be achieved. Here, we designed a fully light-controlled multifunctional artificial vision reflex arc system. The solar cell and oscillator generate presynaptic voltage signals that are then transmitted to a lithium-ion-based memristor for the stimulation of different wavelengths and light intensities. The results show that our artificial vision system can distinguish wavelength and light intensity information and has good weight update symmetry and repeatability. Finally, the deformation experiment of the shape memory alloy demonstrated that the system can be used for controlling artificial muscles under different light signals.

Regime shift in microalgal dynamics: Impact of water level changes on planktonic and benthic algal biomass

Whole-lake microalgal biomass surveys were carried out in Lake Balaton to investigate the seasonal, spatial, and temporal changes of benthic algae, as well as to identify the drivers of the phytobenthos. Phytobenthos was controlled mainly by light: the highest benthic algal biomass was in the shallow littoral region characterized by large grain size (sand) with good light availability but lower nutrient content in the sediment. During the investigated period, phytoplankton biomass showed a significant decrease in almost the entire lake. At the same time, the biomass of benthic algae increased significantly in the eastern areas, increasing the contribution of total lake microalgae biomass (from 20 % to 27 %). Benthic algal biomass increase can be explained by the better light supply, owing to the artificially maintained high water level which greatly mitigates water mixing. The decrease in planktonic algal biomass could be attributed to increased zooplankton grazing, which is otherwise negatively affected by mixing. As a result of the high water level, the trophic structure of the lake has been rearranged in recent decades with a shift from the planktonic life form to the benthic one while the nutrient supply has largely remained unchanged.

Machine vision and artificial intelligence for plant growth stress detection and monitoring: A review

The agricultural sector faces increasing challenges in ensuring food security and optimizing crop yield, necessitating innovative solutions for early detection and mitigation of plant growth stress. The integration of advanced imaging technologies with artificial intelligence (AI) has emerged as a powerful tool for non-invasive, real-time monitoring of plant health. The objective of this paper was to review the application of machine vision and AI in identifying and classifying plant growth stress, with a focus on stressors, datasets, and the use of intelligent algorithms. The significance of plant growth stress induced by environmental variables, including temperature, light, nutrient deficiencies, and water supply were addressed and the conventional stress detection methodologies, underscores their inherent limitations, and establishes the groundwork for the exploration of state-of-the-art technologies in stress assessment. Various sensor technologies were explored, encompassing traditional RGB cameras, multispectral and hyperspectral sensors, and thermal imaging, each capable of capturing distinct stress signatures. Machine vision, leveraging high-resolution imaging and spectroscopy, offers detailed insights into plant physiological responses. Coupled with AI approaches such as deep learning, neural networks, and pattern recognition, machine vision enables the automated analysis of vast datasets, enhancing the accuracy and speed of stress detection. The recent advancements in image processing techniques tailored for plant stress identification were focused and discussed the role of feature extraction, classification, and predictive modelling in achieving robust results. The potentials of AI in plant stress physiology and its role in overcoming the limitations of traditional methods, and the use of unsupervised identification of visual symptoms to quantify stress severity, allowing for the identification of different types of plant stress were studied. Moreover, the potentials of machine vision technology and AI for real-time monitoring and decision support systems in precision agriculture were discussed. The findings of this review would contribute to the growing field of agricultural technology, offering insights into the development of automated tools that could aid farmers and researchers in mitigating the impact of abiotic stressors on crop/plant health and productivity.

The thylakoid proton antiporter KEA3 regulates photosynthesis in response to the chloroplast energy status

Plant photosynthesis contains two functional modules, the light-driven reactions in the thylakoid membrane and the carbon-fixing reactions in the chloroplast stroma. In nature, light availability for photosynthesis often undergoes massive and rapid fluctuations. Efficient and productive use of such variable light supply requires an instant crosstalk and rapid synchronization of both functional modules. Here, we show that this communication involves the stromal exposed C-terminus of the thylakoid K+-exchange antiporter KEA3, which regulates the ΔpH across the thylakoid membrane and therefore pH-dependent photoprotection. By combining in silico, in vitro, and in vivo approaches, we demonstrate that the KEA3 C-terminus senses the energy state of the chloroplast in a pH-dependent manner and regulates transport activity in response. Together our data pinpoint a regulatory feedback loop by which the stromal energy state orchestrates light capture and photoprotection via multi-level regulation of KEA3.

Life Cycle Assessment of Exopolysaccharides and Phycocyanin Production with Arthrospira platensis

In the pursuit of sustainable solutions for contemporary environmental challenges arising from the increasing global demand for energy, this study delves into the potential of cyanobacteria, specifically Arthrospira platensis (commonly known as “spirulina”), as a versatile resource. Employing a life cycle assessment (LCA) in accordance with the ISO 14044:2006 standard and employing both midpoint and endpoint indicators, the study comprehensively evaluates environmental impacts. The research explored a range of scenarios, specifically investigating variations in light intensity and harvesting volume. These investigations were carried out using a pilot-scale photobioreactor, specifically an airlift reactor system featuring a horizontal tubular downcomer. The primary focus is on extracting valuable compounds, namely exopolysaccharides and phycocyanin. It emphasized the extraction of value-added products and strategic integration with a biogas plant for process heat, contributing to developing a sustainable supply network and offering insights into environmentally conscious algae cultivation practices with implications for renewable energy and the production of valuable products. The results emphasize the project’s potential economic feasibility with minimal energy impact from by-product extraction. The environmental assessment identifies marine ecotoxicity and fossil resource depletion as principal impacts, predominantly influenced by upstreaming and harvesting stages. After conducting comparisons across various scenarios, it was found that cultivations under higher light intensities have a lower environmental impact than cultivations with low light supply. However, regardless of light intensity, processes with shorter harvesting cycles tend to have a smaller environmental impact compared to processes with longer harvesting cycles. Overall, this research contributes a nuanced and realistic perspective, fostering informed decision-making in sustainable algae cultivation practices, with implications for renewable energy and valuable compound production.

Comparison of Cr and Sr doping into TiO2 for photocatalytic removal of gaseous 1,2 dichloroethane

1,2-dichloroethane/DCE, a volatile organic compounds (VOCs), can carry out damage to human health and be emitted from various industrial activities. Therefore, development of an eco-friendly process for removal of DCE is critical to improve the air quality index and further protect human health. Photocatalytic activity has been recognized as an efficient strategy in removing various types of VOCs. Owing to its compatibility to be conducted under mild condition, photocatalytic reaction is also favorable. Performance of TiO2, a widely applied photocatalyst, can be improved by the doping of various metal elements, like Sr and Cr. Besides, the doping process might also promote the suitability of photocatalyst to be operated under visible light. This study explored performance of various ratios of Sr/TiO2 and Cr/TiO2 under illumination of UV light. 0.01 %Sr/TiO2 achieved the best DCE removal and was further applied examination using various temperatures, along with concentration of DCE and O2. The presence of O2 played an important role during the photocatalytic reaction. Characterization, reaction kinetics study, and analysis of byproducts were also investigated in this study. A short-extended assessment was also applied to examine the performance under blue light and white light illumination. Contrary, Cr performed the best DCE photocatalytic removal under the supply of visible light.

Research on Temporal and Spatial Distribution Pattern of the Night-Time Economy Supported by Multi-Source Data—A Case Study of Xiamen City, Fujian Province, China

The increasing proportion of night consumption in the total daily consumption means the night economy has become an indispensable part of national economic development. However, early social science research on alcohol in the night economy and social science research on the night leisure industry dominated our understanding of the night city. Few researchers have built effective mathematical statistical models to explore the spatio-temporal distribution and regional interactions of the night economy. This paper presents a method to analyze the spatial and temporal distribution pattern of the night economy based on multi-source data. Firstly, K-Means++ and DBSCAN were used to cluster OD points to identify the gathering areas of night activities. Then, the local L-function in “flow space” was used to extract the aggregated flow of each aggregation area and analyze the regional interactions. Finally, the correlation between night activity and night service facilities was calculated by using geographic detector, and night activity and lighting were coupled by the profit and loss value. The research shows that this method can identify the main areas of night activity, dig out the interrelationships at the community level, and find the new night activity gathering points and night economic growth areas in the future. This study extends the current situation that the night economy is limited to theoretical research and research in central urban areas, provides the temporal and spatial distribution of night activities and night lighting supplies from the perspective of big data, and provides a basis for future night economy research, urban planning, and relevant policy issuance.