Illuminance Values Research Articles

Enhancing energy efficiency in shipping container house: a novel approach using hybrid louver systems

Reusing shipping containers for residential purposes offers a promising approach to address global energy consumption challenges from economic and environmental perspectives. This study parametrically designed hybrid louver shadings by combining fixed vertical triangular slats with variable-depth horizontal rectangular slats, offering a novel approach to shading prefabricated buildings. The energy consumption, daylighting performance, and visual comfort were assessed for various shading configurations. Results indicated that implementing the proposed hybrid louvers, featuring fixed vertical triangular slats and variable-depth horizontal rectangular slats, significantly reduced Energy Use Intensity (EUI) to 133.95 kWh/m2. Moreover, Useful daylight illuminance (UDI), Daylight Autonomy (DA), and Glare Autonomy (GA) values improved to 95.38%, 89.97%, and 91.16%, respectively. The study highlighted the potential of the proposed shading system to significantly reduce overall energy consumption across various ASHRAE climate zones, including Miami (1A), Guangzhou (2A), Melbourne (3C), Esperance (3C), San Diego (3A), and Milan (4A). Notably, energy reductions of up to 50.2% were projected for climates such as Miami (1A) and San Diego (3A). Furthermore, container buildings in warm climate zones exhibited a significantly lower EUI range of 76.58 to 91.95 kWh/m². This study underscores the transformative potential of hybrid louver systems in promoting the widespread adoption of sustainable residential architecture, contributing to global sustainability efforts.

Artificial Neural Network to Predict Curvature Light Shelf Design Related Daylighting Optimization on Office Spaces

Energy Optimization in building design field now has been revolutionized due to AI and machine learning applications. Leveraging daylight to reduce artificial lighting consumption holds promise for significant energy savings, yet the nonlinear nature of daylight patterns poses challenges in prediction and optimization. This study proposes a novel approach to automated light shelf design using machine learning algorithms, specifically artificial neural networks (ANNs) such as recurrent neural networks (RNN) by long short term memory (LSTM), to accelerate daylighting simulation and optimization processes. The methodology employed two distinct approaches: Firstly, we employed the theoretical-analytical approach to explore methods for utilizing machine learning in natural lighting and light shelf parameters. Second, the practical and applied method involved creating a predictive model for designing the light shelf using appropriate AI and ML techniques. This model is based on an office geometry model at the El Arish weather file in Egypt, four-dimensional training room models with three internal zones-oriented south. Rhinoceros and Grasshopper, two parametric simulation tools, are used to normalize and optimize light shelf parameters like geometry cross-section, curvature surface, width, height position, depth, tilt angle, and reflectance materials. Then, the Galapagos plug-in and Colibri2 are used for dataset creation and optimization. The results demonstrate that automated light shelf operation has a significant impact on internal daylighting quality. RNNs enable rapid prediction of optimization models, reducing time consumption in the early design phase. ML facilitates decision-making by generating evaluative criteria from user-selected design options. RNNs were classified as good and bad and used LSTM to enhance prediction accuracy for efficient illuminance values metric in zones 1 and 2. Challenges include increasing the simulation procedure's efficiency. The results of model accuracy reached 99%. Hence, future research should prioritize resolving the previously identified concerns. In conclusion, this study underscores the importance of ML-driven approaches in early design phases to optimize building energy consumption and pave the way for sustainable architectural practices.

Designing Tb3+‐Sensitized Silica‐Nanoparticles‐Aided Eu3+‐Doped Sr2SiO4 Phosphors with Enhanced Luminescence for Anti‐Counterfeiting Applications

Silica‐nanoparticles‐assisted Eu3+‐doped Sr2SiO4 and Tb3+‐ and Eu3+‐co‐doped Sr2SiO4 phosphors, as potential phosphors for anti‐counterfeiting application are synthesized via a solid‐state reaction technique. The crystal structure, photoluminescence, and decay times are investigated. The characteristic emission of Eu3+‐doped Sr2SiO4 phosphors exhibits two major peaks at 617 and 595 nm under an excitation wavelength of 394 nm, which corresponds to 5D0 → 7F2 and 5D0 → 7F1 electron transitions of Eu3+ ions. Upon co‐doping with Tb3+, the red emission intensities of the Eu3+‐doped Sr2SiO4 phosphors are enhanced by 1.78‐fold times through an energy‐transfer process. The optimized Tb3+‐ and Eu3+‐co‐doped Sr2SiO4 phosphors show a decay time of 0.49 ns and an energy‐transfer efficiency of 73%. The calculated International Commission on Illumination value (x, y) and color purity are (0.63, 0.37) and 94%, respectively. Subsequently, a luminescent ink is formulated using the optimized phosphor and tested for efficiency on currency notes. Additionally, a flexible film is fabricated, and its luminescence properties are studied. The formulated ink can serve as security ink in the anti‐counterfeiting application.

Testing the use of daylight-linked control systems to address integrative lighting and energy savings in office buildings

Daylight-linked control systems (DLCSs) are used to maintain constant work plane illuminance and save energy. If properly calibrated, they could be used to guarantee circadian requirements fulfilment as well. In this study, the functioning of a closed-loop proportional dimming system is simulated based on on-field measurements. Simulations are performed calibrating the system to achieve different targets: three work plane task illuminances (300 lx, 500 lx, 750 lx) and one melanopic equivalent daylight illuminance (melEDI) value (250 lx) alternatively. Four electric light CCT profiles (stable at 3000 K, 4000 K, and 6500 K, and variable during the day) are considered. Results demonstrate that when the system is calibrated according to work plane illuminance, melEDI values are always fulfilled under clear sky and with overcast sky when task illuminance and CCT are high. When the system is calibrated to meet circadian requirements, the CCT choice is crucial to guarantee work plane illuminance.

Shifts in light availability driven by dieback across a marsh‐forest gradient

AbstractEcological zonation in coastal forests is driven by sea level rise and storm‐surge events. Mature trees that can survive moderately saline conditions show signs of stress when soil salinity increases above its tolerance levels. As leaf burn, foliar damage, and defoliation reduce tree canopy cover, light gaps form within the crown. At the forest‐marsh edge, canopy cover loss is most severe; trunks of dead trees without canopies form “ghost forests.” Canopy thinning and light from the edge alter conditions for understory vegetation, promoting the growth of shrubs and facilitating establishment and spread of invasive species that were previously limited by light competition. In this research, we present an analysis of illuminance and temperature in a coastal forest transitioning to a salt marsh. Light sensors above the ground surface were used to measure light attenuation of trees and understory vegetation and to observe the effect of reduced canopies at the forest‐marsh edge. Farther from the marsh, where salinity is lower and trees are healthy, dense canopies attenuate light. We estimate that during the growing season, tree canopies intercept 50% of illuminance on average. Closer to the marsh, canopy thinning, and tree death allow greater light penetration from above, as well as from the adjacent marsh. These illuminance values are further increased by light penetration from the forest‐marsh edge (edge effect). Here, higher illuminance may permit Phragmites australis expansion. At intermediate locations, trees intercept between 32% and 49% of light and the understory shrub Morella cerifera intercepts a further 45% of penetrating light based on comparisons of illuminance above and below shrub canopies. Light penetration from the edge can also be felt. The presence of M. cerifera reduces the air temperature close to the soil surface, creating a cooler summer microclimate. The tree health state is reflected in the canopy size. The canopy patterns and the edge effect are responsible for light availability distribution along forest‐marsh gradients, consequently affecting the understory vegetation biomass. We conclude that during forest retreat driven by sea level rise, tree dieback increases light availability favoring the temporary encroachment of Ph. australis and M. cerifera in the understory.

Construction of a Model for Assessing the Comfort of Residential Indoor Environment Based on Multisensory Design

Economic development and technological progress have made people’s demand for indoor environments higher and higher, and designing safe, comfortable, and healthy indoor environments through multisensory design is worthy of serious consideration. In order to realize the assessment of indoor environment comfort under multi-sensory design, this paper carries out data assessment from three dimensions of thermal environment, light environment and air environment. Relying on the PMV model of thermal environment comfort, we analyze the trends of indoor temperature and humidity, average radiant temperature, and PMV values. Combine Weber-Fechler and lighting coefficient to study the visual comfort change of indoor light environment, and analyze the lighting illuminance of indoor light environment under different working conditions by illuminance uniformity. From the basic principle of indoor wind environment, the changes of effective temperature difference and blowing sense caused by air temperature and wind speed are investigated. The temperature difference of the south-facing room decreased between 12.14% and 15.65% before and after the heating was stopped, which is a small change. The average indoor ambient radiant temperature values at different measurement points were up to 27.59 °C, and the fluctuations of the average indoor thermal ambient PMV values were within the range of [-1.2,1.6]. When the indoor light ambient illuminance value increased from 200 lux to 600 lux, the visual comfort improvement was more significant than from 600 lux to 1000 lux. The indoor air distribution characteristic ADPI value was 100% when the air velocity was 0.15m/s and 0.25m/s. Based on the results of indoor environment comfort assessment, multisensory optimization of indoor environment comfort from heat, light and air environments is proposed to provide guidance for improving people’s satisfaction with indoor environment.

Analysis and Evaluation of Artificial Lighting in the Passenger Spaces of a 500 Gt Ro-Ro Ferry

Lighting is an important design criterion for ships, including the ro-ro ferry. The ship’s lighting system must meet certain standards. Therefore, the present study analysed and evaluated the artificial lighting of an Indonesian ro-ro ferry. The analysed ship in the present research was a 500 GT ro-ro ferry named KMP. Takabonerate that operated across the Selayar Islands of Indonesia. The artificial lighting systems in this ship’s three passenger spaces, which are reclining seat room, sofa seat room, and passenger open space, were evaluated and analysed. The main parameter to be investigated was the room illuminance produced by the ship’s lighting system. In order to achieve the study objective, the illuminance in those rooms was calculated using analytical formulas. The calculation results were validated using direct measurements and computer simulation. The direct measurements were conducted using a luxmeter, while computer simulations were performed using DIAlux Evo 10.0 software. With this software, the artificial lighting in the passenger spaces was also simulated and realistically visualized. The research results showed that the illuminance in the reclining seat room and the sofa seat room had met the minimum illuminance value set by the Indonesian National Standard (SNI), American Bureau of Shipping (ABS), and Indonesian Classification Bureau (BKI) standards. For the passenger open space, a re-arrangement of the lighting system was conducted to improve the light distribution so that all space illumination can meet the specified standards.

Ultraviolet radiation from solariums: the main problems of measurement and evaluation of results

Introduction. Artificial tanning is now considered a public health issue. There is strong evidence linking tanning bed use to the risk of skin cancer. One measure to reduce the health risks associated with artificial tanning is to control exposure to ultraviolet radiation (UVR). Assessing the compliance of UV solariums with hygienic standards requires solving two main problems – methodological and instrumental support for the measurements taken. The purpose of the study was to substantiate methodological approaches to measuring UVR irradiance in solariums. Material and methods. Regulatory and methodological documents, as well as literary sources devoted to the issues of conducting UVR measurements of solariums and the criteria for assessing their compliance, were analyzed. To justify the conditions and scope of research, measurements of the energy illumination of the UVR of a mini-solarium, and pilot studies in a vertical turbo solarium using a UV Radiometer were carried out. Results. According to the results of UVR measurements at the minimum possible distance from the radiating block of the mini-solarium, the highest values ​​of energy illumination in all ranges were obtained at the central point, which was also confirmed by the results of scanning the radiating surface. Analysis of the research results in a vertical turbo solarium at a distance of 0.3 m from the central vertical axis of the solarium showed that the highest values ​​of energy illumination for the two blocks were obtained at different heights (1.0 m and 0.5 m from the supporting surface), which confirms the need to carry out measurements at several points along the height of each radiating block. Limitations. The results of the study can only be used when measuring the irradiance of ultraviolet radiation in solariums using UV radiometers. Conclusion. The proposed methodological approaches make it possible to measure the energy illumination of ultraviolet radiation in places where solariums are used, process and format of the results obtained, and evaluate them for compliance with current hygienic standards. Issues arised when carrying out measurements and assessing energy illumination in the spectral region of 200–400 nm when examining solariums are identified.

Optimising Daylighting Performance Through Side light with Passive Devise Design in Buildings

Passive lighting design plays an important role in providing natural lighting to save electricity consumption in buildings. This study aims to investigate the performance of natural lighting and the potential of alternative designs through sidelights with 3 shading device models and light shelves with different sizes in north, west, east, and south orientations. This research method is quantitative, which describes the measurement results in existing conditions and radiance illuminance software simulations. The results showed that at the beginning of field measurements, it was known that there were rooms with lighting intensity too high, too low, and uneven distribution. The simulation results use Radiance Illuminance software to determine the illuminance value of light distribution into space in the morning, afternoon, and evening. Improvised designs are applied with shading device models on the building envelope, namely horizontal, vertical, and egg-crate models in spaces oriented toward the East and West. This study also applied an interior-exterior light self-model measuring 50 cm, 100 cm, and 150 cm of space with the orientation of window openings towards the North and South. The simulation results in this study, show that without a shading device and using a horizontal model, there will be a decrease of 0.4% at a distance of 2 m from window openings oriented to the East, while to the West will be able to increase the illuminance value by 11.5% at a distance of 10.5 m from the window opening. Buildings without using light self and using interior-exterior light shelves measuring 50 cm can increase the illuminance value by 0.5% at a distance of 10.5 m from window openings in a space oriented towards the North, while the orientation towards the south, which can be increased the illuminance value by 0.4% at a distance of 6 m from the window opening. Based on this research analysis, it concluded that the best-improvised design in rooms oriented toward North and South is a 50 cm interior-exterior light shelf and horizontal shading device models are the best for spaces oriented to the East and West. This study, also concluded that the orientation of the building, the passive device model, and the distance of the measuring point in the building envelope, affect the intensity and distribution of daylight entering the building.

The Hypogeous Roman Archeological Museum of Positano: Study of the Evolution of Biological Threaten and Development of Adequate Control Protocols.

Hypogea are natural or artificial spaces located underground often of great interest from an anthropological, archeological, religious, artistic, or historic point of view. Due to their features, these environments usually present conservative problems and biological colonization could be considered as one of the main threats. The present three-year study was carried out by specialists of the Central Institute for Restoration of Rome (ICR) in the hypogeous site preserved in the Roman Archeological Museum of Positano (Positano MAR) and focused on characterizing biological alterations present on the mural paintings; setting up efficient strategies and protocols for biodeterioration control; and monitoring the efficacy of direct and indirect interventions. Patinas with different morphologies were analyzed through microscopic observations, cultural analyses and next-generation sequencing. The results proved that the alterations comprised a great variety of microorganisms forming very distinct communities, differently distributed over space and time. The main taxa represented were bacteria of phyla Pseudomonadota and Actinomycetota, fungi belonging to the genus Fusarium and Gliocladium, and algae of the genus Chlorococcum. Preservation protocols were set up considering the alterations' composition and included the application of biocides, limiting daily temperature changes, decreasing illuminance values on painted surfaces, and the screening of natural light sources.

Visual environment in schools and student depressive symptoms: Insights from a prospective study across multiple cities in eastern China

ObjectiveTo investigate the effects of the school visual environment on depressive symptoms in children and adolescents based on cohort study in eastern China. The school visual environment-related indicators included in this study comprise personal factors (visual impairment) and school-related factors (classroom lighting, school green spaces and school air quality). MethodThe follow-up cohort comprises 15,348 students from 283 primary and secondary schools in eastern China. This represents the one-year outcomes of a school-based myopia-mental health cohort study. Data collection includes basic demographics (age, gender, region, etc.), physical examination indicators, behavioral indicators, and school visual environment-related indicators. ResultAfter a one-year follow-up, we found that compared to the more severe vision impairment group (≤4.0), healthy vision group (≥5.0) had a positive effect against the occurrence of depressive symptoms during consecutive follow-ups, with an RR value of 0.61 (95% CI: 0.57–0.66). Higher values of blackboard illumination appear to be associated with greater positive effects, with an RR (Q75%∼Q100% range) value of 0.87(95% CI: 0.81–0.93). School green spaces seem to exhibit relatively good positive effects when in the Q25%∼Q75% range. The combination of physical activity (Weekly high-intensity exercise) with school air quality(PM2.5≤50%)showed a better positive effect, with an RR value of 0.51(95%CI:0.48–0.55). ConclusionWhen addressing students' depressive symptoms, it is crucial to improve the visual environment both at the school level and in students' personal level. Paying appropriate attention to modifiable behaviors, like regular participation in high-intensity exercise sessions, can help alleviate students' depressive symptoms.

Efficiency Analysis of a Passive Daylighting System Based on Northern Malaysia’s Climate

Daylighting design strategy is important in order to have adequate lighting source in a room and necessary to decrease energy consumption for artificial lighting. Passive daylighting system utilizes daylight by collecting, reflecting and diffusing the natural light throughout a given area. The purpose for this study is to monitor, compare and analyse an optimum light pipe system design that can scatter daylight into a room based on three case studies. Lighting analysis was conducted using Autodesk 3ds Max Design software throughout the project based on the actual geographical parameters of Universiti Malaysia Perlis, Malaysia and also using the real sun azimuth on working hours. The results were compared according to the respective designs in order to observe the maximum internal illuminance and the average internal illuminance. The results show that the straight geometry with low aspect ratio produces the highest interior light intensity among other light pipe systems and the average internal illuminance values in the room was able to reach the minimum requirement of a small room which is 200 – 500 lux.

Contrast enhancement algorithm for infrared images based on atmospheric scattering model

With the rapid development of infrared technology, infrared cameras are widely used in the military, medical, and industrial fields. However, the thermal radiation information received by infrared cameras often undergoes degradation due to random factors such as scattering or reflection during transmission. Consequently, the final infrared image suffers from poor contrast and blurred vision. To address these problems, this paper proposes an infrared image contrast enhancement algorithm based on the atmospheric scattering model. Firstly, we modify the hypothesis of the dark channel prior theory, and the pseudo dark channel prior theory is deduced to meet the processing requirements of single-channel images. Secondly, we propose anti-target interference and filtering threshold method to accurately estimate the atmospheric illumination value and transmittance of the atmospheric scattering model. These methods effectively mitigate the influence of infrared targets on the atmospheric illumination value and eliminate the blocking artifact effect caused by pixel value jumps in the transmittance images. Furthermore, we employ adaptive histogram equalization with contrast limitation, highlighting the global contrast. This paper conducts experiments on the M3FD dataset and employs objective evaluations using Visible Edge (E), Figure Definition (FD), Peak Signal-to-Noise Ratio (PSNR), Information Entropy (IE), Structure Similarity Index Measure (SSIM), and Visual Information Fidelity (VIF). The results indicate that the proposed algorithm enhances the overall contrast of images while highlighting fine texture details, exhibiting good visual effects. Both subjective and objective evaluations outperform seven other contrast algorithms, demonstrating the effectiveness of the proposed method.

Illumination matters part I: comparative analysis of light sources and illumination in flexible ureteroscopy-fundamental findings from a PEARLS analysis

PurposeIllumination characteristics of flexible ureteroscopes have been evaluated in air, but not in saline, the native operative medium for endourology. The aim was to evaluate light properties of contemporary ureteroscopes in air versus saline, light distribution analysis, and color temperature.MethodsWe evaluated the Storz Flex-Xc and Flex-X2s, Olympus V3 and P7, Pusen 7.5F and 9.2F, and OTU WiScope using a 3D printed black target board in-vitro model submerged in saline. A spectrometer was used for lux and color temperature measurements at different opening locations.ResultsIlluminance was higher in saline compared to air (5679 vs. 5205 lx with Flex-Xc, p = 0.02). Illuminance in saline differed between ureteroscopes (ANOVA p < 0.001), with highest for the Flex-Xc at 100% brightness setting (5679 lx), followed by Pusen 9.2F (5280 lx), Flex-X2s (4613 lx), P7 (4371 lx), V3 (2374 lx), WiScope (582 lx) and finally Pusen 7.5F (255 lx). The same ranking was found at 50% brightness setting, with the highest ureteroscope illuminance value 34 times that of the scope with lowest illuminance.Most scopes had maximum illuminance off center, with skewness. Three scopes had two light sources, with one light source for all other scopes. Inter-scope comparisons revealed significant differences of color temperature (ANOVA p < 0.001).ConclusionThe study demonstrates the presence of inhomogeneous light spread as well as large differences in illumination properties of ureteroscopes, possibly impacting on the performance of individual scopes in vivo. Additionally, the study suggests that future studies on illumination characteristics of flexible ureteroscopes should ideally be done in saline, and no longer in air.

Research on the Design of Recessed Balconies in University Dormitories in Cold Regions Based on Multi-Objective Optimization

Thermal comfort and daylighting are vital components of dormitory environments. However, enhancing indoor lighting conditions may lead to increased annual energy consumption and decreased thermal comfort. Therefore, it is crucial to identify methods to reduce buildings’ energy costs while maintaining occupants’ thermal comfort and daylighting. Taking the dormitory building of Songyuan No. 2 at Shandong Jianzhu University of Architecture, which is located in a cold region, as an example, a field measurement analysis was conducted on the recessed balconies within the dormitory. The measured data were analyzed and utilized to simulate the annual energy consumption, thermal comfort predicted mean vote (PMV), and useful daylight illuminance (UDI) values of the dormitory units using the Grasshopper platform with the Ladybug and Honeybee plugins. The different depths of the balconies and window-to-wall ratios have a significant impact on the indoor physical environment and energy consumption, leading to the design of independent variables and the construction of a simplified parametric model. The simulation results underwent multi-objective optimization using genetic algorithm theory through the Octopus platform, resulting in a Pareto optimal solution set. Comparisons between the final-generation data and simulations of the original Song II dormitory unit indicate potential energy savings of up to 2.5%, with a 25% improvement in indoor thermal comfort satisfaction. Although there was no significant improvement in the UDI value, all the solution sets meet the minimum requirement of 300 lux specified by relevant regulations, according to the simulated average illuminance levels on the indoor work plane. Finally, the 60 optimal solution sets were further screened, filtering out sets deviating excessively from certain objectives, to identify 6 optimal solutions that are more balanced and exhibit a higher overall optimization rate. These findings offer detailed data references to assist in the design of dormitory buildings in cold regions.

Objective Comparison of White Light and Narrow-Band Imaging for Detecting Scars, Sulci and Nodules.

Narrow-band imaging (NBI) can improve detection of lesions in the aerodigestive tract. However, its role in benign lesions of the larynx is unclear. This study aims to determine whether NBI improves the detection of scars, sulci, and nodules compared to panchromatic lighting using objective image analysis. In total, 120 vocal folds (VFs) were analyzed with and without NBI (21 normal, 15 scars, 16 sulci, and 45 nodules). Each VF image had anterior, middle, and posterior thirds analyzed for brightness using an area morphometry software (Optimas 5.1a). The middle-third with the lesion was analyzed against surrounding VF segments for average and standard deviation (SD) in absolute grayscale. The use of panchromatic light resulted in greater illumination and grayscale values than NBI. All lesions tended to be in the mid-membranous fold. Under panchromatic light, change in brightness when comparing anterior versus middle (A-M) was +6.1% for normal, versus 6.5%, 8.1%, and 7.1% for sulci, nodules, and scars, respectively. Under NBI, they were 9.0% (normal), 12.3% (sulci), 13.7% (nodules), and 13.1% (scars). A greater SD of luminescence was observed at pathology sites (p < 0.05) when using NBI. The change in absolute grayscale at all lesion sites was greater when using NBI than when using panchromatic light (p < 0.05). NBI significantly enhanced the area of pathology in patients with nodules, sulci, and scars. Greater SD values in grayscale at pathologic sites were observed compared at normal sites. Thus, NBI may improve the detection of phonotraumatic lesions compared to panchromatic light. N/A Laryngoscope, 134:4066-4070, 2024.

Performance comparison of different filters based on fibre optic lighting systems and evaluation of architectural lighting effects

Plastic optical fiber lighting is a feasible green lighting method for buildings. This study first derives a mathematical model for the focused light energy absorbed by optical fibers. Based on the variable relationships in the mathematical model, the cooling mechanism of plastic optical fibers was obtained. Secondly, a dual-axis automatic sun-tracking concentrating lighting equipment capable of carrying nine Fresnel lenses was designed. The equipment was used to compare the filtering and cooling effects of two types of filter devices: infrared filters and heat-insulating film. The cooling and lighting effects of these two types of filter devices were also evaluated. Subsequently, the impact of fiber loops on lighting was discussed. Finally, the b2 and b3 modules of the dual-axis automatic sun-tracking concentrating lighting equipment were applied in dark stairwells. The results indicate that the temperature of optical fibers can be reduced by using filtering devices and enhancing heat radiation and convection on the surface of optical fibers. Infrared filters exhibit better cooling and lighting effects than heat-insulating film. Looping the fiber cable reduces the effect of fiber lighting, and the higher the number of loops, the higher the loss of fiber lighting. The dual-axis automatic sun-tracking concentrating lighting equipment increased the illuminance value in the stairwells to over 50 lux, showing great application potential in architectural lighting.

Enhanced Visual Performance for In–Vehicle Reading Task Evaluated by Preferences, Emotions and Sustained Attention

The proliferation of electric and hybrid vehicles has made it possible for people to read and work in a stationary vehicle for extended periods. However, the current commonly used in–vehicle lighting design is still centered around driving and driving safety. Following recommendations from the literature, a neutral white color band (4000 K–5000 K) with 50–100 lx at the vehicle table area is favored. Whether this lighting environment can meet the needs to enhance the reading performance in a modern vehicle was investigated in this presented study. Therefore, in total, 12 lighting settings were designed based on combinations of four illuminance levels (50 lx, 100 lx, 150 lx and 200 lx) and three correlated color temperatures (3000 K, 4000 K and 5000 K); we recruited 19 subjects (12 females, 7 males) and let study participants evaluate each condition based on electronic and paper reading. Next, subjective preferences, positive and negative emotions, feeling of fatigue and sustained attention were tested. We found that higher illuminance and higher CCT (Correlated Color Temperature) can significantly improve the performance of in–vehicle readers in most aspects following Kruithof’s law (p &lt; 0.05). Among them, we recommend the combination of 150 lx and 4000 K as the light parameters for in–vehicle reading as a new development guideline. In addition, we also discovered the inconsistency of people’s lighting preferences between in–vehicle spaces and conventional spaces. For indoor lighting, illuminance values up to 1000 lx are still favored. For an in–vehicle function, starting with 200 lx, the preference level and reading performance already declined. In comparison between electronic and paper reading, both were similarly evaluated. These results show that a neutral white light color should be chosen with a horizontal illuminance of maximal 150 lx for a reading light function independent of the reading device. Interdisciplinarily speaking, our findings can be applied in similar small spaces or transportation modes with gentle acceleration and deceleration such as small space hotel rooms, trains, airplanes or ships.

Lighting characteristics of public space in urban functional areas based on SDGSAT-1 glimmer imagery:A case study in Beijing, China

The artificial light sources in urban areas constitute the primary source of stable nighttime illumination, which can be utilized to reflect the nighttime human activity and the conditions of public space lighting. The previous studies have focused on the evaluation of lighting environments in specific scenarios and the public's perception of these lighting environments. There has been limited analysis of the characteristics of public space lighting and its influencing factors in detail across different urban functional areas. This study primarily utilizes high-resolution SDGSAT-1 glimmer imagery and data from field measurements of lighting attributes to analyze the characteristics of public space lighting and its influencing factors in various urban functional areas. Furthermore, it establishes a quantitative relationship between measured illuminance and glimmer imagery to assess public space lighting levels. The results show that: (1) Various urban functional areas exhibit different illuminance levels, but they all maintain good illuminance uniformity. Additionally, to reduce the impact of the blue light spectrum on public visual perception, urban public space lighting primarily utilizes warm color temperatures with low color rendering properties. However, nighttime public space lighting cannot always achieve a balance between public comfort and high color rendering; (2) In the main urban area of Beijing, 98.5% of illuminance values fall within the range of 0 to 35 lx, indicating that most areas have good public lighting conditions. However, cases of over-illumination are also observed; (3) The building height has a positive correlation with public space lighting, while vegetation density exhibits a negative correlation. This study explored the characteristics of public space lighting in different urban functional areas and conducted a large-scale analysis of urban public lighting conditions using high-resolution nighttime images, providing evidence for the design and optimization of public space lighting in cities and better serving urban sustainable development, and contributing to the achievement of UN Sustainable Development Goal 11.7: By 2030, provide universal access to safe, inclusive, accessible, green and sustainable public spaces, particularly for women, children, older persons and persons with disabilities.

Spatiotemporal light exposure modeling for environmental circadian misalignment and solar jetlag.

Light exposure is the most powerful resetting signal for circadian rhythms. The objective of this study was to develop and validate a high-resolution geospatial light exposure model that measures environmental circadian misalignment (or solar jetlag) as the mismatch between the social clock and sun clock, which occurs from geographic variation in light exposure leading to delayed circadian phase from relatively less morning light exposure and greater evening light exposure with increasing westward position within a time zone. The light exposure model (30 m2 spatial resolution) incorporated geospatial data across the United States on time zones, elevation (using Google Earth Engine), sunrise time, and sunset time to estimate solar jetlag scores (higher values indicate higher environmental circadian misalignment). The validation study compared the light exposure model in 2022, which was linked with geocoded residential addresses of n = 20 participants in Boston, MA (eastern time zone position) and Seattle, WA (western time zone position) using a geographic information system, with illuminance values captured from wearable LYS light sensors and with sun times from the Solar Calculator. Western versus eastern positions within a time zone were associated with higher solar jetlag scores from the light exposure model (P < 0.01) and relatively larger differences in sunset time measured using light sensors (social clock) and the Solar Calculator (sun clock) (P = 0.04). We developed and validated a geospatial light exposure model, enabling high spatiotemporal resolution and comprehensive characterization of geographic variation in light exposure potentially impacting circadian phase in epidemiologic studies.