Lighting Research & Technology最新文献

Visual and non-visual responses of drivers to simulated LED headlights varying in correlated colour temperature 驾驶员对相关色温变化的模拟LED大灯的视觉和非视觉反应

3区工程技术

Lighting Research & Technology Pub Date : 2023-11-13 DOI: 10.1177/14771535231203570

A Mehri, R Golmohammadi, M Aliabadi, M Farhadian, JD Bullough, M Samavati

{"title":"Visual and non-visual responses of drivers to simulated LED headlights varying in correlated colour temperature","authors":"A Mehri, R Golmohammadi, M Aliabadi, M Farhadian, JD Bullough, M Samavati","doi":"10.1177/14771535231203570","DOIUrl":"https://doi.org/10.1177/14771535231203570","url":null,"abstract":"This study aimed to investigate the impact of automotive headlights of different correlated colour temperatures (CCT) on the visual and non-visual performance of drivers. Forty drivers participated in the study, driving in a simulated night road for 45 min in three sessions. The LED headlights had CCTs of 3176 K, 4358 K and 6923 K, with an illuminance of 5 lx perpendicular to the participants’ eyes. Heart rate variability (HRV), psychomotor vigilance task and Karolinska sleepiness scale were measured before and after driving. At the end of the trials, achromatic far and near visual acuity tests, as well as achromatic far and near contrast sensitivity tests, were conducted. The study revealed that CCT did not affect achromatic far and near visual acuity. However, CCT had an impact on achromatic near and far contrast sensitivity, with higher CCT resulting in improved achromatic contrast sensitivity. As the CCT decreased, participants exhibited increased reaction time, made more errors, and reported higher sleepiness. The most significant physiological changes in HRV, including alterations in low frequency (LF), high frequency (HF) and LF/HF, were observed at lower CCT. The findings of this study suggest that both the visual and non-visual performance of drivers were enhanced when high CCTs were used for automotive LED headlights.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"130 18","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136352122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Design, analysis and validation of Customised Homocentric Fresnel Collector based on longest wavelength of visible spectrum 基于可见光谱最长波长的定制同心菲涅耳集热器的设计、分析和验证

3区工程技术

Lighting Research & Technology Pub Date : 2023-11-13 DOI: 10.1177/14771535231207099

V Kumar, DS Bisht, H Garg

{"title":"Design, analysis and validation of Customised Homocentric Fresnel Collector based on longest wavelength of visible spectrum","authors":"V Kumar, DS Bisht, H Garg","doi":"10.1177/14771535231207099","DOIUrl":"https://doi.org/10.1177/14771535231207099","url":null,"abstract":"The paper presents the design of a Customised Homocentric Fresnel Collector (CHFC) based on the principle of superposition and the longest wavelength of the visible spectrum. A bottom-to-top approach is proposed that uses an individually designed homocentric prism based on visible light at a wavelength of 740 nm. The homocentric prism of the CHFC follows a uniform height method with varying pitch. An area focus is achieved on the plastic optical fibre (POF) bundle inlet without employing any secondary optical element. The CHFC achieves a uniform distribution of concentrated visible spectrum radiation from the Sun with a significant reduction in the hotspot problem. Comparison of the CHFC versus a mid-wavelength-based Fresnel lens shows that the CHFC delivers 9.24% more visible spectrum radiation on the POF bundle inlet. The simulated optical efficiency of the CHFC is 90.6%. Numerical analysis of a CHFC-based daylighting system shows that 331 lm (efficiency of 39.4%) can be delivered via a 10 m long fibre bundle made up of 32 POF each of 1 mm diameter. Experimental observations demonstrated that the maximum temperature recorded on the POF bundle entrance is 56.8°C during peak direct normal illuminance conditions. Note that the spectral distribution of the radiation emerging from the POF differs from the incident sunlight spectrum because of the transmission characteristics of the optical components used in the CHFC testbed.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"49 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136347512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Life cycle cost analysis of LED retrofit and luminaire replacements for four-foot T8 troffers 四英尺T8灯管LED改造和灯具更换的生命周期成本分析

3区工程技术

Lighting Research & Technology Pub Date : 2023-11-10 DOI: 10.1177/14771535231207810

L Liu, GA Keoleian, GM Lewis

{"title":"Life cycle cost analysis of LED retrofit and luminaire replacements for four-foot T8 troffers","authors":"L Liu, GA Keoleian, GM Lewis","doi":"10.1177/14771535231207810","DOIUrl":"https://doi.org/10.1177/14771535231207810","url":null,"abstract":"Lighting makes up 17% of electrical loads and the largest energy end use in commercial buildings. Linear fixtures are among the largest opportunities for energy efficiency improvement, given their long operating hours. With continued, rapid light-emitting diode (LED) development and more LED replacement products on the market, lighting replacement decisions become more complex and warrant re-examination. With a goal to inform building managers and other decision-makers with practical guidance on lighting replacement, this study is a life cycle cost (LCC) analysis that compares the cost–benefit of six replacement options (one fluorescent and five LED) for a 0.61 m by 1.22 m (2 ft by 4 ft) T8 recessed troffer based on data for 168 lighting products from an online vendor. Results show that direct wire (i.e. unballasted) LED retrofits are the least-cost option to replacing fluorescent lamps in terms of normalized LCC. Plug-and-play lamps suffer from a lock-in with ballasts, but their ease of installation can help spur LED adoption. In cases where an existing ballast is still usable, hybrid LED retrofits provide the least upfront cost option by deferring the cost of rewiring. LED luminaires can offer improved aesthetics and reliability; however, they have high upfront cost. Among them, luminaires with replaceable lamps offer lower cost than those without.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":" 1012","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135185929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Opinion: How to foster a motivating ecosystem for our next generation 意见：如何为我们的下一代营造一个激励的生态系统

IF 2.5 3区工程技术

Lighting Research & Technology Pub Date : 2023-11-01 DOI: 10.1177/14771535231204155

引用次数: 0

Editorial: Special issue for early career researchers in lighting 编辑：照明领域早期职业研究人员特刊

IF 2.5 3区工程技术

Lighting Research & Technology Pub Date : 2023-11-01 DOI: 10.1177/14771535231204154

E. Brembilla, K. Chamilothori

引用次数: 0

User behaviour in public squares after dark 天黑后公共广场上的用户行为

3区工程技术

Lighting Research & Technology Pub Date : 2023-10-21 DOI: 10.1177/14771535231200390

VKR Hennig, N Gentile, S Fotios, C Sternudd, M Johansson

{"title":"User behaviour in public squares after dark","authors":"VKR Hennig, N Gentile, S Fotios, C Sternudd, M Johansson","doi":"10.1177/14771535231200390","DOIUrl":"https://doi.org/10.1177/14771535231200390","url":null,"abstract":"This research concerns the influence of electric lighting on user behaviour in public squares and whether differences in people’s use of the square can be observed between daylight and darkness. Previous research on pedestrians suggests that lighting can support human needs for reassurance, accessibility, comfort and pleasure. While these findings are also likely to be applicable to the use of public squares, there is little empirical evidence to verify that. A field study was conducted to explore user behaviour in two differently illuminated public squares. Observations of the movements and stationary activities of people in the squares were recorded at both squares for the same times of day in the weeks before and after the daylight savings clock change, enabling a comparison of activity in daylight and after dark. 5296 observations were recorded and lighting conditions were captured with HDR-photography and aerial photos. Kirseberg square, with asymmetric luminaires and metal halide lamps, revealed a decrease in stationary activity after dark. Lindeborg square, with omnidirectional luminaires and high-pressure sodium lamps, revealed an increase in stationary activity. In conclusion, the patterns of user behaviour in the two public squares after dark seem to be differently influenced by electric lighting, pointing to a need for further understanding of users’ experience of the squares after dark.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"14 9","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135512977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Investigation of the daylight spectrum in an indoor environment using CIE S 026 melanopic metrics 使用CIE S 026黑视度量法研究室内环境中的日光光谱

3区工程技术

Lighting Research & Technology Pub Date : 2023-10-19 DOI: 10.1177/14771535231204162

M Englezou, A Michael

{"title":"Investigation of the daylight spectrum in an indoor environment using CIE S 026 melanopic metrics","authors":"M Englezou, A Michael","doi":"10.1177/14771535231204162","DOIUrl":"https://doi.org/10.1177/14771535231204162","url":null,"abstract":"Since discovering the intrinsically photosensitive retinal ganglion cells (ipRGCs) and their impact on the circadian rhythm, many disciplines have been researching the physiological and psychological effects of light on humans. However, not much research has been conducted on how the spatial configuration of a room (orientation and gaze direction) changes the light quality and quantity. This research examines the variability of the natural lighting spectrum, focusing on light intensity, the spectrum itself, as well as variations across seasons and hours. The metrics examined are the CIE S 026 melanopic equivalent daylight illuminance (melanopic EDI) and melanopic daylight efficacy ratio (melanopic DER). Field measurements were taken in a room with a south orientation located in Cyprus, using a spectrometer. The main parameters under study were eight gaze directions, four seasons (June, September, December and March) and four different hours each day (09:00, 12:00, 15:00 and 18:00) for 20 positions in the test room. The results show the impact of season, time and gaze direction on the melanopic DER and melanopic EDI. Overall, due to the low sun angle and direct sunlight exposure in the winter, the melanopic EDI was much higher compared to the other three seasons, whereas the melanopic DER had the lowest values. For all seasons and times, most of the cases achieved the minimum recommendation for daytime light exposure of melanopic EDI of more than 250 lx.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135730207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Comparison of questionnaire items for discomfort glare studies in daylit spaces 日光空间不适眩光研究问卷项目比较

3区工程技术

Lighting Research & Technology Pub Date : 2023-10-19 DOI: 10.1177/14771535231203564

Geraldine Quek, Sneha Jain, Caroline Karmann, Clotilde Pierson, Jan Wienold, Marilyne Andersen

{"title":"Comparison of questionnaire items for discomfort glare studies in daylit spaces","authors":"Geraldine Quek, Sneha Jain, Caroline Karmann, Clotilde Pierson, Jan Wienold, Marilyne Andersen","doi":"10.1177/14771535231203564","DOIUrl":"https://doi.org/10.1177/14771535231203564","url":null,"abstract":"When studying discomfort glare, researchers tend to rely on a single questionnaire item to obtain user evaluations. It is unclear whether the choice of questionnaire item affects the distribution of user responses and leads to inconsistencies between studies. This study aims to investigate if different glare questionnaire items yield similar distributions of user discomfort in daylit environments. We conducted a comparative study of selected questionnaire items from previous glare experiments, testing them in three independent user studies with different lighting conditions and glare stimuli. We compared the resulting outputs across questionnaire items with 540 data points from 149 participants. Results indicated that ordinal questionnaire outputs show strong correlations (0.68 < ρ < 0.85), high internal reliability (α = 0.93) and captured the same latent construct. Binary questionnaire items reflected different glare thresholds but still correlated well with ordinal items. The construct validity of tested questionnaire items was confirmed through responses to an open-ended question. These findings suggest that the tested questionnaire items may be used for category rating-type discomfort glare evaluations and consistently capture the same construct.","PeriodicalId":18133,"journal":{"name":"Lighting Research & Technology","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135730530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The impact of woven shade fabrics on correlated colour temperature and illuminance with daylighting 编织遮阳织物对日光照明相关色温和照度的影响

IF 2.5 3区工程技术

Lighting Research & Technology Pub Date : 2023-10-01 DOI: 10.1177/14771535221077350

A. Villalba, J. Yamín Garretón, A. Pattini

引用次数: 0

Correspondence: Experiences from lighting intervention studies in a hospital 通信:某医院照明干预研究的经验

3区工程技术

Lighting Research & Technology Pub Date : 2023-09-20 DOI: 10.1177/14771535231198565

H Hemphälä, J Lindén, P Lanbeck, J Niléhn

引用次数: 0