Illumination Levels Research Articles

An Insula-Enriched Regulator of Retinoic Acid Marks a New Intersection in the Neural Circuitry of Mouse Social Behavior

An Insula-Enriched Regulator of Retinoic Acid Marks a New Intersection in the Neural Circuitry of Mouse Social Behavior

Natural lighting optimization through configuration of shading device for library in East Jakarta

Visual comfort is an important thing to consider in designing a library. The quality of lighting in reading rooms in public libraries in Jakarta is still below the SNI lighting standard of 300 lux. This study will discuss about optimizing and utilizing natural lighting for the reading room by using a combination of several types of shading devices. The method used is performing simulations and comparisons. A total of 138 types of shading devices were simulated with the VELUX Daylight Visualizer software and compared to find the best results. The results of the comparative analysis show that the GH1-19 shading device provides the most optimal results with an average illumination level of 548 lux and a uniformity ratio of 0.81 simulated in different seasons, times, and orientations.

An Investigation of Light Spectrum and Intensity on Depression among Older Adults

The impact of lighting in buildings on managing behavioural and psychological symptoms, particularly in older adults, is significant as it affects visual and circadian systems. With age-related changes in eyes and circadian system, specialized lighting design is crucial to promote mood and overall well-being in older people. This study aimed to assess the effects of two types of ambient lighting interventions on depression in older adults. Both interventions involved creating a direct/indirect ambient illumination with high illuminance level (500 lux) in the morning (8:00-12:00), followed by gradual dimming throughout the day until reaching 100 lux in the evening (after 20:00). Depression levels were measured before, during, and after the lighting interventions using the Geriatric Depression Scale. The results showed a significant decrease in depression after exposure to both lighting conditions, with greater reduction observed in the L2 intervention. These findings highlight the positive effects of incorporating varying illumination and spectrum in the ambient lighting quality of residential buildings. Considering that older adults spend most of their time indoors, designing ambient lighting with varying intensity and tuning spectrum throughout the day could be a promising therapeutic approach to reduce depression, create an environment that promotes mental health, and improve the overall quality of life in older adults.

Illuminance in Office Workstations and Related Health Risks in a Tertiary Institution within Edo State, Nigeria

The extent of illumination within work places contributes to the productivity and wellbeing of the employees. Due to its relevance, health and safety organizations around the world have continued to instruct and enlighten employers on the necessity to place satisfactory lighting equipment’s and mechanisms in place to guarantee the constant safety and wellbeing of their employees. This research is aimed at accessing the illuminance levels in office work stations in the Faculty of Life Sciences, University of Benin. Survey method was used to obtain primary data on the perception of the employees about illumination levels within their work environment and associated health risk. Illumination levels were measured within the work environment using a digital lux meter. The values obtained were compared with standards as set by the Occupational Safety Health and Administration (OSHA). The surveys conducted revealed that majority of the workers were unsatisfied with the lighting conditions. Illuminance readings taken shows that majority of the workstations had levels below (194.0-453.0Lux) the recommended standard of 500Lux, while others were above (524.4-666.9Lux). Health risks associated with bad illumination includes: eyestrain, stress, teary eyes and headaches. It is recommended that illumination levels be adjusted in areas where they are considered lower or higher than the set standards within the work stations. Workers should also be enlightened on the possible health risks associated with poor lightening conditions together with regular checking of illumination levels in all work stations of the institute.

Photovoltaic and electrical investigation of In/WOx/CuPc/In heterojunctions with light intensity-dependent NDR behaviours

A peripherally tetrachalcone substituted copper(II) phthalocyanine was achieved by cyclotetramerization of the phthalonitrile in the presence of anhydrous CuCl2. The modified CuPc was thermally coated on WOx thin films from which a In/WOx/CuPc/In heterojunction was obtained. The surface of the thin films was investigated using scanning electron microscopy (SEM), where energy dispersive X-ray spectra (EDX) was used to confirm chemical structure. The crystal structures of the thin films were characterized using X-ray diffractometry (XRD). To determine the photovoltaic properties of the heterojunction, I–V plots were obtained under dark and various levels of illumination. It was seen that the heterojunction was responsive to the external light. Using the I–V plots, different diode parameters such as ideality factor, barrier height, series resistance, etc., were calculated. These plots also revealed that the In/WOx/CuPc/In heterojunction exhibits negative differential resistance (NDR) characteristics. Photodiode characteristics indicate that the heterojunction exhibits self-powered photodiode behaviours. It was seen that In/WOx/CuPc/In heterojunctions are sensitive to the external light that photovoltaic characteristics alter when the light intensity alters. However, no clear relation between the light intensity and photovoltaic characteristics were evidenced.

SOLAR ENERGY CONTROL STRATEGY USING INTERACTIVE MODULES

The concept of interactive canopy emerged as a notable manifestation of smart buildings in architectural endeavors, using artificial intelligence applications in computational architecture, interactive canopies came as a potential response for living organisms to combat external environmental changes as well as reduce energy consumption in buildings. This research aims to explore architecture with higher efficiency through the impact of environmentally technological factors on the design form by introducing solar energy into the design process through the implementation of interactive curtains that interact with the sun in the form of an umbrella. The main objective of the umbrellas is to protect the users from the sun's harmful rays. After designing an interactive cell using Grasshopper, the methodology follows an analytical and experimental approach, the analytical section is summarized by conducting a case study of multiple models and analyzing the techniques used in these models to discover the significant advantages and disadvantages of the design. While the experimental section demonstrates the mechanism for implementing the interactive modules. The research suggests that by designing an interactive canopy that responds to external changes and senses solar radiation in ways that when the intensity of solar radiation increases and the sun is perpendicular to the dynamic units, will lead to maintaining a more balanced level of illumination. The work efficiency is studied by simulating it by Climate Studio.

High-contrast interaction-free quantum imaging method

Quantum imaging techniques offer enhanced resolution, contrast, and precision at ultralow illumination levels compared to traditional imaging approaches. Relying on the unique properties of entangled photon pairs, two of these techniques stand out: the correlation-based quantum imaging technique provides visibility enhancement in imaging of a low-reflectivity object which is subject to excessive noise and losses, while the interaction-free ghost imaging allows for probing the presence of an object with an ultimately low number of photons. Here we propose a quantum imaging scheme that combines the unique advantages of these two approaches. We show that this scheme offers high-contrast imaging of objects with a minimal number of photons that can minimize thermal noise efficiently and create background-free images. We anticipate that this approach can find application in the imaging of photosensitive biological tissues in a noninvasive and harm-free fashion.

Building energy conservation potentials of semi-transparent CdTe integrated photovoltaic window systems in Bangladesh context

Building integrated photovoltaic systems are getting popular worldwide due to their building energy conservation properties alongside emission-free electricity generation capabilities. BIPV is a suitable way to generate renewable energy without wasting any land or building space. Bangladesh has set a target to generate a great portion of its electricity from solar energy and has already implemented different photovoltaic applications. However, Bangladesh still has no policy and guidelines to implement BIPV technology in its different types of buildings. In this study, we investigated the energy conservation potentials of three different configurations of semi-transparent CdTe combined building integrated window systems in an office building considering Bangladesh's climate conditions. To investigate the building energy conservation potentials of BIPV window systems, an EnergyPlus-based numerical simulation model was developed and validated with outdoor experiment data. The annual energy simulation results indicate that in all climate conditions, CdTe combined BIPV windows can save ranging from around 30–61% of electricity consumption compared to conventional window systems. Besides, it generate around 270 kWh electricity and ensure indoor daylight illuminance level at 300 lux. Moreover, in all climate conditions, south-faced BIPV windows are more efficient for power generation, but east-faced windows are more efficient to reduce net electricity consumption.

Visual Comfort and Discomfort in Public Boarding Secondary Schools in Nairobi City County, Kenya

Indoor light quality is the intensity and amount of illumination of interior spaces. Technological developments have led to the utilisation of artificial natural light. Illumination is crucial in the visibility of tasks. Quality of light can influence the visual comfort and ocular health of the students. Although Kenya lacks lighting standards for schools, ISO and CIE provide international guidelines on optimal illumination for various facilities. This study was conducted on public boarding secondary schools in Nairobi City County to assess the visual comfort or discomfort of students in classrooms. The study utilised a cross-sectional descriptive study design. Four hundred twenty-three students were randomly sampled from 8 schools. Illumination levels were measured in 38 classrooms using a calibrated Benetech GM1010 light metre and compared to levels recommended by ISO and CIE. A self-administered semi-structured questionnaire was used to collect data on students’ visual comfort or discomfort. Data was analysed using SPSS version 23. Descriptive data were analysed using frequencies, while inferential data were analysed using chi-square. The study established that 15% of the respondents experience visual comfort during the day, 13.5% at night, and 12.7% both day and night. Fourteen classrooms achieved the recommended illumination level at 7:30, 20 at 13:00 hours, and 10 at 18:00 hours. Recorded levels ranged from 56.71 lux to 1289.93 lux. The study found a statistically significant association between visual comfort and factors such as existing eye problems, presence of blinds or curtains, number of windows, presence of whiteboards, classroom orientation and student sitting positions. The study recommends that public secondary schools need to ensure quality indoor illumination in their facilities to enhance the visual comfort of students in learning facilities.

Multi-performative façade systems: The case of real-time adaptive BIPV shading systems to enhance energy generation potential and visual comfort

Building envelopes invariably tend to be static systems that encounter various performance limitations such as inefficient illuminance admittance, and heat and moisture transmission owing to their non-responsiveness towards environmental fluctuations. In contrast to such façade solutions, responsive façade systems with embedded sensing, actuation, and control systems have been proven to perform with up to 65% higher efficiency by being able to adapt their physical characters, such as orientation, and material property in real-time as a response to fluctuating environmental conditions (visual and thermal) and user preferences. Advancements in artificial intelligence and machine learning processes further aid such responsive façade systems to optimize multiple parameters such as illuminance level and the associated lighting energy, visual discomfort caused by solar glare, solar heat gain, thermal resistance (heating energy and comfort level), and natural ventilation simultaneously. This research investigates the case of a real-time adaptive Building Integrated Photo Voltaic (BIPV) shading system and its ability (in comparison with traditional static building integrated photo voltaic façade systems) to perform as regards visual comfort and energy generation potential simultaneously within the humid subtropical climate of Sydney, Australia. A simulated case scenario wherein a real-time adaptive building integrated photo voltaic shading systems is deployed on a typical multistorey building façade in Sydney, Australia is accordingly presented. The conducted simulation considers the responsive building integrated photo voltaic system as a double-skin façade system and uses multi-objective evolutionary computing principles to decipher its integrability potential. A comparative analysis between traditional static mounted Photo Voltaic (PV) systems as opposed to multi-objective optimization driven real-time adaptive building integrated photo voltaic shading configurations is subsequently presented. The ability to maximize generated energy, while simultaneously maintaining visual comfort is thus a unique proposition of this research.

An approach for improving Optical Character Recognition using Contrast enhancement technique

Digital cameras and mobile image capture of documents are two examples of new developments in the fields of optical character recognition and text recognition. Scans of text or text photographic images and even natural photography results can be distorted to the point where OCR digitization is inaccurate. It offers a unique non-parametric unattended approach to correct unwanted document image distortions to achieve optimal OCR accuracy. It applies a highly effective stack of document image enhancement algorithms to restore perfect images distorted by unknown sources of distortion. First, it provides a means of modifying local brightness and contrast in order to better handle different illumination levels and atypical light transmission patterns in the image. Then apply a nifty grayscale conversion method to your photo to give it a new look. Third, it uses unsharp masking techniques to further enhance important details in grayscale images. Finally, we use the best global binarization technique to prepare the final document image for OCR recognition. The proposed technique has the potential to significantly improve the text recognition rate and accuracy of optical character recognition.

DAYLIGHTING PERFORMANCE OF HIGH SCHOOL LEARNING ENVIRONMENT IN TROPICS

ABSTRACT The quality of the indoor environment, including the lighting conditions, is crucial in classrooms as it directly affects students’ learning performance and productivity. Natural light is the best light source for visual comfort, aesthetics, and energy efficiency. Malaysia is in a tropical region and has abundant daylight availability that could meet the required lighting during the day. However, in Malaysian schools, electric lights are frequently switched on during classes in the daytime; hence, daylighting is not efficiently utilised. This study investigates the daylighting performance in classrooms in a national high school in Penang, Malaysia. Fieldwork was conducted by measuring incident illumination levels inside selected classrooms in the Teluk Kumbar High School. The results show that average illumination levels were between 400 lux to 1000 lux, more than enough in most classrooms because of the relatively large windows with clear glass. The average daylight ratios recorded in the classrooms were between 6.4 and 9.2%, which may result in glare problems. Simulations were conducted using Design-Builder to further evaluate the annual daylighting performance including Daylight Autonomy (DA), Annual Sun Exposure (ASE) and Useful Daylight Illuminance (UDI). Based on the findings, it is recommended to use shading devices or replace the glazing type to improve daylighting performance for visual comfort. Proper design and selection of windows in schools can significantly improve indoor lighting quality for students and reduce solar heat gain.

The Effect of Correlated Color Temperature and Illumination Level of LED Lighting on Visual Comfort during Sustained Attention Activities

LED lighting has been widely used in various scenes, but there are few studies on the impact of LED lighting on visual comfort in sustained attention tasks. This paper aims to explore the influence of correlated color temperature (CCT) and illuminance level in LED lighting parameters on human visual comfort. We selected 46 healthy college students (23 male and 23 female). The ages ranged from 22 to 26 years old (average age was 24.2 years). Electroencephalogram (EEG) signals, sustained attention to response test (SART) parameters and subjective evaluation parameters of subjects performing sustained attention tasks under LED lighting were obtained. The results under different conditions were compared, and the effects of experimental lighting parameters on visual comfort were discussed. The results showed that the LED lighting with CCT of 3300 K and illuminance of 300 lx was more comfortable than other combined conditions. In the subjective perception of subjects, 4000 K CCT also had good visual comfort evaluation and caused good task performance. Therefore, our study showed that in sustained attention tasks, when LED lighting conditions were CCT of 3300 and 4300 K and illuminance level was 300 lx, the visual comfort of the subjects was better.

Influence of Headlight Level on Object Detection in Urban Traffic at Night

The purpose of this work is to determine the influence of the low beam intensity of motor vehicle headlights on detection conditions in urban traffic. For this purpose, studies with fourteen subjects are conducted on three differently illuminated test roads, in which the low beam intensity is dimmed from off to fully on. At each dimming level, the subjects indicate whether or not they have detected the object, which is realized by a flat target and occurs at sixteen different positions in front of the vehicle. In addition, considerations of the contrast curve and the visibility level are made in order to determine the influence of switched off and fully switched on headlights. The results show that the negative contrast created by the existing street lighting creates detection conditions at least as good as full low beam intensity in almost all cases. The results further indicate that the influence of the low beam intensity increases with decreasing distance to the object and decreasing illumination levels. The results of this work show that an increase in low beam intensity initially leads to poorer detection conditions; thus, the option of reducing low beam intensity should be considered in urban traffic space.

Method to Calculate Melanopic Light Reaching the Retina Depending on the Optical Density of an Aging Crystalline Lens

Lighting studies that take into account the age of the inhabitants of an area and are related to circadian light are difficult to find. This study aims to simplify a method to approximately compute the circadian light reaching the retina based on photopic illuminance reaching the corneal plane and considering the optical density of an aging crystalline lens. As an example of this proposed method, calculations were performed with both the D65 and A standard illuminants, showing how the spectral power distribution is modified by the optical density of the crystalline lens, mainly at short wavelengths. Due to these selective wavelength absorptions of the aged lens, a significant variation in the level of daylight equivalent melanopic illuminance (EDI) is present in the retina. With levels of 200 lux at the corneal plane, these variations ranged from 204 EDI lux to 178 EDI lux for the D65 standard illuminant, and from 99 EDI lux to 101 EDI lux for the A standard illuminant for observers aged 10 and 90, respectively. In this work, we aimed to simplify the greatest possible level of calculation of melanopic light, while describing simple protocols that are easy to translate into practice. Our results will allow researchers to carry out optimized lighting designs from both the photometric and circadian perspectives considering the optical density of an aging lens.

Improving Natural Lighting Performance in Historical Education Venues: Ulugazi Primary School

Natural lighting is an essential factor in the design of educational buildings, as it creates an environment that provides psychological satisfaction, increases motivation, encourages healthier conditions and saves energy. Using the same finishing materials in classrooms facing different directions and sizes in educational buildings causes natural lighting effects of different quantity and quality. This situation creates psychological, physiological and cognitive inequality among students. This negativity can be annihilated by changing facade elements, the ratio of the transparent surface and the materials. However, these applications should be made with minor interventions in the historic structure. Within the scope of this study, which aims to determine the current natural lighting performance of the classrooms in Ulugazi Primary School, a historic school building in Kocaeli, the scenarios are designed with approaches that will have the most negligible impact on the building identity.
 
 In this context, with the Climatestudio analyzes were conducted for four classes with different characteristics. Visual comfort problems were determined with the Spatial Daylight Autonomy (sDA) that evaluate the illuminance level annually and with the Annual Sunlight Exposure (ASE) that reveal the glare probability, within the scope of Leed V4.1. Furthermore, scenarios were created with the choice of finishing materials and curtains with different optical properties for the interior wall surfaces and ceiling, which have lost their authentic value, based on the same metrics. Thus, it has been revealed to what extent the quantity, quality and distribution of natural lighting in classrooms have changed. According to the simulation results, it was determined that there were significant glare problems in two of the four classes, with ASE ranges ranging from 0% to 31.4%. Class B facing south and east, has the most significant glare potential. In addition, all classrooms spatially provide the sDA value. However, more illuminance levels are required in the back corners of the classrooms.

Lighting color temperature impacts effort-related cardiovascular response to an auditory short-term memory task

To better understand the impact of environmental light on processes that underlie cognitive activity, Lasauskaite and Cajochen (2018) recently proposed a theoretical model that predicts how light's correlated color temperature (CCT) affects effort. Here we tested whether the effects of CCT of light on effort-related cardiovascular response also extend to another sensory input—hearing. In two experimental blocks, participants were exposed to either low (2800 K) or high correlated color temperature (6500 K) light with an illumination level of 500 lux for 15 min before and while they performed an auditory n-back task varying in difficulty level (low difficulty/1-back vs. moderate difficulty/2-back). Mental effort was indexed as sympathetic beta-adrenergic impact on the heart, measured via cardiac pre-ejection period and systolic blood pressure. Based on the theoretical model, we hypothesized that light with a high CCT should lead to lower mental effort compared to light with a low CCT in both the low and moderate task difficulty conditions. Moreover, moderate task difficulty should lead to stronger effort compared to an easy task. The results did not show expected differences in invested effort levels between the task difficulty conditions (1-back vs. 2-back task) measured by cardiac pre-ejection period and systolic blood pressure. However, in line with our prediction, the results indicated that higher CCT of light decreased effort during an auditory memory task. Task performance was higher in easy than moderate task difficulty but was not altered by lighting conditions. Furthermore, we found no significant associations between cardiovascular reactivity and changes in mood, sleepiness, light, task, or effort ratings. Taken together, our results provide first evidence that higher CCT of light reduces the amount of effort invested during cognitive tasks for which hearing is needed. Given that this study was conducted under controlled laboratory conditions and with healthy young participants, additional research is needed to demonstrate that our results generalize to real-life applications. Nevertheless, we recommend that lower CCT of light should be avoided in learning and work contexts, as it might lead to higher effort and cardiovascular reactivity that may contribute to the development of cardiovascular health problems. Instead, we recommend higher CCT of light during daytime for wellbeing and health.

Rationale for Parameters of Energy-Saving Illumination inside Agricultural Premises and Method of Its Values Calculation

High-quality lighting of premises in the cultivation of farm animals is an important condition for the successful development of the agro-industrial complex. Sufficient lighting with the simulation of sunrise and sunset which increases daylight hours to 15–16 h can raise the level of production by 8–15%. The most innovative, economical and efficient light source for livestock, poultry and greenhouse buildings are LED lamps allowing for a short payback period. The difference between the models developed by the authors and the traditional point method is taking into account lamp length o, lamp suspension height, location of the illuminated area under the lamp at displacement and observation angles, and luminous flux of light source, and the most important thing is body angle of the light source. This paper presents the method for calculating illumination under the LED lamp due to the large error in the values obtained by theoretical methods due to the lack of a correction factor for changing the illumination of the lamp (0.8). Prediction of crystal heating was carried out by verification calculation in the ANSYS/CFX software package. Forecasting the illumination of the fodder table was carried out by calculation in the DIALux evo software package. The main parameters of an energy-saving LED lamp (power consumption, luminous flux, color temperature and color) were selected. The consumption of electrical energy decreased by 85%; the average level of illumination increased and amounted to 123.1 lux. The developed method for calculating the illumination under the LED lamp can be considered satisfactory, the Student and Fisher criteria do not exceed tabular values and the correlation coefficient showed a close relationship. To comply with electrical safety standards in the premises, a resonant power supply system for LED lamps is offered.

Research on the Preferred Illuminance in Office Environments Based on EEG

The quality of the indoor light environment in buildings directly influences the emotional state, health condition, and work efficiency of people. The application of EEG to indoor light environments is beneficial to further reveal the neural mechanisms of light comfort. In this study, the absolute power of spontaneous EEG was calculated as an objective physiological index, and its trend with the illuminance level of the task area was analyzed. Then, the absolute power of the band, which has the strongest correlation with subjective evaluation and task performance, was selected as the characteristic value. The subjective and objective parameters were validated to explore the preferred illuminance choices for subjects’ comfort and efficiency during the rest stage and the task stage, respectively. The results showed that the power of the δ band and β band at partial channels in the parietal region had statistically significant differences under five illuminance levels in the resting state. The total logarithmic power of EEG and the logarithmic power of the δ band at the Cz channel were negatively correlated with the subjective evaluation. The total logarithmic power of EEG was relatively low when the subjective evaluation was comfortable. There was no statistical difference in the total EEG logarithmic power among the five illuminance levels in the task state, but the subjects had the highest performance indicator and the best cognitive task performance at 500 lux and 750 lux conditions. This research may provide a design reference for the selection of task area illuminance levels for staff during high-intensity mental work and rest.

Assessment of Environmental Parameters and Occupational Health Hazards of Rural Women in Post Harvest Activities of Assam

Agriculture is the oldest and most dangerous occupation as compared to other occupations. Agriculture is the major national economic contributor for under-developed nations such as India, Brazil, and South Korea. It was estimated that nearly half of the world labor force involved in agricultural activities. An attempt was undertaken to assess the environmental parameters and occupational health hazards in the view point of environmental conditions in post harvest activities. Three blocks were selected randomly from Jorhat sub-division. Two villages from each block were selected randomly and there by all together six villages and 300 farm women were selected proportionately. Both interview and experimental method was considered for collection of data. Personal and demographic characteristics of the respondents showed that 82 per cent belonged to marginal farmers having 1 acre of land. As regards to age of the respondents, 88 per cent falls in the age group of 30-40 years. The mean temperature was found to be 22°C and mean relative humidity (RH) was observed to be 49 per cent. The lighting condition revealed that the illuminance level were ranges from 21 lux to 95 lux. It was found that mean noise level was 110 db which was more than the permissible limit. Hazards faced by farm women in post harvest activities due to the environmental factors are pain or cramps, indigestion, eye strain, watering of eyes, blurred vision or vision problem, loss of hearing capacity, temporary deafness, headaches and faintness due to working under cold, humid, noisy and inadequate lighting conditions. It was apparent that 63 per cent respondents were belonged to ‘high’ incidence of environmental hazards during the performance of post harvest activities. The angles of average flexion was highest in upper arm (90.62) and extension was in thoracic and it was observed 115.30°indicating deviation of body parts.