Due to the influence of COVID-19, there is a need to create an environment where people can relax and feel special in a separated space. Therefore, in this study, we will clarify the psychological changes that occur when people are surrounded by an unusual environment. This study prepared eight LED lighting colours: red, orange, yellow, green, blue, light blue, purple, and white. The room was illuminated, and the participants were asked to evaluate their impressions using the SD method on a 7-point scale. As a result of impression evaluation, red gave a warm impression, yellow gave a bright impression, blue gave a cold impression, and purple gave a mature impression, just like the psychological effects of colours. Green gave an artificial impression that was different from the psychological effects of the other colours. From these results, we can conclude that impressions do not correlate with colour symbolism when the entire room is illuminated with coloured light. In the future, we will clarify the relationship between wavelength and impression by studying the spectral distribution of each light source.

AbstractThis research focuses on the investigation of the effect of a new light emitting diode (LED)-lighting system which reproduces indoor museum conditions, on some self-made art paint colours (acrylic-, alkyd-, and linseed oil-based paints) often used in modern-contemporary art. A halogen lamp representing a traditional light source for museum lighting was also considered. Lighting-set-up and lighting optimization parameters were considered while Ultraviolet/Visible/Near Infrared (UV/Vis/NIR) spectrophotometry was used for investigating the colour change of the paint samples. Univariate analyses allowed determining the highest effect of the lighting systems on the linseed oil binder and ultramarine blue PB29 mixture upon ageing, according to the highest total colour change ΔE*ab. In a more specific and detailed way, variance analyses not only demonstrated the strong correlation between the type of binder and pigment used for the paint samples with the colour variation, but also showed that the short-wavelength blue LEDs influenced the change along the yellow–blue b* axis of the yellow and blue samples, whereas the halogen lamp mostly had an impact towards the red–green a* axis of mostly the green specimens.

Purpose The recent surge in light emitting diode (LED) lighting retrofitted into schools in the UK is as a result of the UK Government’s 2050 zero carbon pledge. However, the benefits and consequences of LED retrofit projects for staff and enablers and stakeholder knowledge gaps about LED lighting retrofitting have not been fully explored. The aim of this research is to determine the amount of savings in cost, carbon reduction and kilowatt usage and to confirm if repayment from energy and cost savings derived from LED retrofit school projects funded through the SALIX funding option in the UK would be enough to service the loan. Thus, it examines monetary and non-monetary benefits, internal project stakeholder knowledge gaps and the consequences of LED retrofit for the staff and enablers of a large community college in the UK which is funded through the SALIX funding option. Design/methodology/approach The methodology relied on a hybrid research approach of a case secondary school through the review of literature, analysis of secondary data, focus group and questionnaire survey. The focus group consists of six key project stakeholders. The secondary data was sourced from the Project IGP [Individual Grade Proposal] and the Positive Energy Report from Zenergi, and the closed online questionnaire survey was used to sample 150 teaching staff and school enablers. Findings The findings show that stakeholders lack project knowledge, trust and expertise/project comprehension. This is in terms of baseline information, LED technology/management, payback modalities, management of risks and ethical issues around environmental impact. The forecasted SALIX savings were not achieved in real-time, partly because it does not take into consideration the increase in energy costs over the payback period. However, the LED retrofit creates efficiencies; drives down energy costs and energy usage; and drives carbon reduction, helping pupils’ learning, improving productivity and performance, and finally leading to a better lighting environment for the school community. Originality/value The study will help schools in the UK that intend to access SALIX finance for LED retrofits to understand the challenges and mitigate the risks. It will also help the government to understand the importance of adjusting the payback modalities to the base price when the retrofit was carried out for real-time savings to be made. The research would be useful in ensuring the proactive involvement of all the identified stakeholders in understanding the challenges and what the function entails.

Abstract Lighting is the key factor affecting oviposition time. The oviposition time is directly related to ovulation, which occurs 5 hours after reaching the peak concentration of luteinizing hormone in the blood, which depends on the lighting regime. This paper studies the impact of the “subjective day” duration under intermittent LED lighting on the daily rhythm of oviposition and the productivity of hens of the productive flocks of cross SP-789. The “subjective day” lasted 16 hours per day for group 1, 15 h for group 2, 14 h for group 3 and 13 h for group 4. It was established that the shorter the duration of the “subjective day”, the earlier the hens begin and finish laying. So, in groups 1, 2, 3, and 4, hens began laying eggs at 4 a.m., 3 a.m., 2 a.m., and 1 a.m. and ended at 6 p.m., 4 p.m., 4 p.m., and 3 p.m. with an average time of laying eggs of 8.67; 7.36; 5.36 and 5.27 h, respectively. In groups 1, 2, 3, and 4 the livability of hens, weight of eggs, egg production and yield of egg weight per the initial laying hen, feed consumption for 10 eggs and 1 kg of egg weight were 98.0, 97.0, 99.0, 99.0%; 60.0, 59.9, 60.4, 59.7 g; 123.9, 124.1, 130.3, 126.1 pcs, 7.48, 7.47, 7.97, 7.63 kg; 1.37, 1.36, 1.32, 1.36, and 2.28, 2.26, 2.18, 2.26 kg, respectively.

Abstract A study was conducted to evaluate the effect of LED lighting on the growth of seedlings of hybrid tomato plants. Four hybrids (Captain F1, Refiner F1, Coral Reef F1 and Fire F1), seven treatments of irradiators (monochromatic red, green, blue, white) and three dual light treatments (green+blue, blue+red, green+red) were carried out in the laboratory of artificial climate. Radiation with monochromatic had a role in increasing hypocotyl length, the height of plant, transpiration and stomata connection. The results have shown a significant effect on radiation with monochromatic red on hypocotyl length (73.00mm) and the height of plant (30.94cm). Plants radiation with monochromatic blue gave the highest transpiration (4.69 mmol/m2.s) and stomatal conductance (0.30 mol./m2.s). The dual radiation had a role in increasing dry weight for the plant and leaf chlorophyll content (SPAD). Radiation with (green+red) provided the best stem dry weight (0.91g). Plants irradiated with (green+blue) exhibited the highest leaf dry weight and root dry weight (1.96g and 3.12g respectively). Plants radiation with (blue + red) showed the highest leaf chlorophyll content (SPAD) (559.19). In the monochromatic light, the effect of hybrid Fire F1 showed the highest hypocotyl length (64.11mm) and height of plant (29.00 cm), and hybrid Refind F1 had the highest transpiration (3.58 mmol/m2.s) and stomatal conductance (0.23 mol./m2.s). In the binary spectral effect, the hybrid Coral reef F1 resulted the highest stem dry weight, leaf dry weight and root dry weight (0.68 g,1.76 g and 2.39g respectively), and hybrid Refind F1 had the highest leaf chlorophyll content (SPAD) (468.27).

Abstract Earlier studies have shown that low Correlated Color Temperature of lighting (CCT) may induce a warmer thermal sensation than high CCTs at the same ambient temperature. The current study investigated if the association between CCT and thermal sensation would persist when subjects worked on computers, were exposed for longer duration and when the study population included older subjects whose vision may have changed with age. The study was carried out in a climate chamber with controllable LED lighting and where CCT could be gradually changed. Generally, the association between CCT and thermal sensation was weak and not significant. However, at 22°C and short-term exposure, the results indicated that high CCT caused a cooler thermal sensation. This association disappeared with more prolonged exposure duration and when subjects worked on a computer. Comparison of responses to lighting exposure of the two groups of subjects with mean ages of 24 years and 44 years showed no difference in their perceived thermal sensation when the CCT was changed. However, the older group of subjects could not distinguish differences in CCTs above 4000 K. The findings suggest that the magnitude of the effect of lighting on thermal perception is modest and only visible under exceptional and tightly controlled conditions that do not mirror actual buildings.