Journal articles: 'Lighting ratio'

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Zhou, Zhi Hua, Shan Hu, and Tao Du. "Study on Determination of Best Window-Wall Ratio of Office Building in Cold Area." Applied Mechanics and Materials 260-261 (December 2012): 209–16. http://dx.doi.org/10.4028/www.scientific.net/amm.260-261.209.

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The cooling and heating load caused by the heat transfer of the window is significantly greater than that caused by the heat transfer of wall because of the large heat transfer coefficient of the window. At the same time, the sun radiate heat through the window into indoor can increase the cooling load and decrease the heating load; the natural lighting enhances, and the lighting energy consumption decreases because of entering sunlight. The paper took a low energy consumption office building in the northern China for example, synthetically analyzed the cooling energy consumption, heating energy consumption and lighting energy consumption of every orientation under the condition of lighting control or no lighting control. The results show that comparing with no lighting control, the energy consumption with lighting control is less. When using lighting control, the best WWR of south, north, east, west are 0.35, 0.3, 0.3, 0.25, respectively; then the building energy saving rate is 8.2%.

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Šístková, M., A. Peterka, and B. Peterka. "Light and noise conditions of buildings for breeding dairy cows." Research in Agricultural Engineering 56, No. 3 (August 26, 2010): 92–98. http://dx.doi.org/10.17221/43/2009-rae.

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Check measurement of the illuminance, the uniformity ratio of illuminance and noise level was made in the selected stable building to prove quality of lightning both for service workers and the cattle. The measurement discovered that the noise level, the day lighting and artificial lighting do not satisfy valid health standards and can have harmful effect upon human and cattle organism. In the monitored stable building the permissible hygienic limit of noise was exceeded only during distribution of feed and bedding and it only for the short time.

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Ishii, H., H. Kanagawa, Y. Shimamura, K. Uchiyama, K. Miyagi, F. Obayashi, and H. Shimoda. "Intellectual productivity under task ambient lighting." Lighting Research & Technology 50, no. 2 (June 27, 2016): 237–52. http://dx.doi.org/10.1177/1477153516656034.

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An experiment was conducted to evaluate intellectual productivity in three lighting conditions: (a) conventional ambient lighting, (b) task ambient lighting with normal colour temperature (5000 K) and (c) task ambient lighting with high colour temperature (6200 K). In the experiment, cognitive tasks were given to 24 participants. The concentration time ratio, which is a quantitative and objective evaluation index of the degree of concentration, was measured. The results showed that the average concentration time ratio under the task ambient lighting with high colour temperature was 72.5%, which was 5.0% points higher than that under the conventional ambient lighting. It is believed that intellectual work can be performed better when the concentration time ratio is high.

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Junlin, Zong, and Zhang Longwei. "Multi objective optimization of window to wall ratio of University Gymnasium in severe cold area by coupling natural lighting and energy consumption." E3S Web of Conferences 293 (2021): 02044. http://dx.doi.org/10.1051/e3sconf/202129302044.

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Objective To explore the relationship between window opening ratio and natural lighting and energy consumption of University Gymnasiums in severe cold area, and put forward optimization strategies. Methods Digital simulation technology was used to simulate the energy consumption and natural lighting of University Gymnasium window opening ratio, and the window opening scheme with natural lighting and low energy consumption was obtained. Conclusion The side window lighting should be used in the window opening scheme of small and medium-sized university gymnasiums. Within the range of experimental data, the North-South lighting is the main lighting mode, and the East-West lighting is the auxiliary.

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Akashi, Yukio, Sueko Kanaya, and Akihiro Yagi. "Relationship between Concentration of Subjects and the Illuminance Ratio between Ambient Lighting and Task Lighting." JOURNAL OF THE ILLUMINATING ENGINEERING INSTITUTE OF JAPAN 80, no. 8 (1996): 540–49. http://dx.doi.org/10.2150/jieij1980.80.8_540.

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Durmuş, İ., and S. Kalebaşi. "Effect of fluctuate lighting on performance of laying hens (Short Communication)." Archives Animal Breeding 52, no. 2 (October 10, 2009): 200–204. http://dx.doi.org/10.5194/aab-52-200-2009.

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Abstract. This study was carried out to investigate the effects of fluctuate lighting on performance of laying hens. Two programs were applied with 16 hours daily lighting: step-up (normal) lighting program as the control treatment and a fluctuate lighting program of 2 W/m2 for 45 min and 6 W/m2 for 15 min. Egg weight, feed consumption, feed conversion ratio, henday egg production and hen-housed egg production of the laying hens were recorded for 46 weeks. No significant difference for hen-day and hen-housed egg production between the step up and fluctuate lighting programs (P>0.05) were found. However, fluctuate lighting program resulted in a significant increase in egg weight (P<0.05). Moreover, hens in the fluctuate lighting program consumed significantly less amount of feed and had a better feed conversion ratio than hens in the step-up lighting program (P<0.01). The results of the present study indicate that fluctuate lighting can be used for a profitable egg production.

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Kim, Kyeong-Mi, Young-Won Kim, Seung-Taek Oh, and Jae-Hyun Lim. "Development of a natural light reproduction system for maintaining the circadian rhythm." Indoor and Built Environment 29, no. 1 (June 11, 2019): 132–44. http://dx.doi.org/10.1177/1420326x19855421.

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Circadian rhythm is linked to sleep, arousal and human health overall, affecting body temperature and heart rate. A 24-h natural-light cycle provides optimum lighting environment for humans. However, as people increasingly stay indoors with artificial lighting, lacking periodic characteristics, imbalance in the circadian rhythm ensues. Previous lighting-related studies to resolve such problem partially provided the colour temperatures of natural light but failed to reproduce the 24-h periodic characteristics of it. This study proposes a natural light-reproducing system that provides the daylight cycle characteristics of natural light in order to maintain the circadian rhythm. Natural light was measured through an optical measurement equipment, while the characteristics (colour temperature and short-wavelength ratio) of natural light by season and time were analysed. Subsequently, the control indicator of seasonal and hourly lighting was extracted and applied to the light-emitting diode lighting to provide lighting service, executing a daylight cycle that reflects the characteristics of natural light. After the sunset, especially, the circadian rhythm was maintained by minimizing the short-wavelength ratio of the lighting while maintaining indoor illumination.

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Fotios, S., and Q. Yao. "The association between correlated colour temperature and scotopic/photopic ratio." Lighting Research & Technology 51, no. 5 (July 3, 2018): 803–13. http://dx.doi.org/10.1177/1477153518779637.

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The scotopic/photopic ratio (S/P) is a parameter that may be considered in the design of road lighting. This paper compares the S/P ratio and correlated colour temperature (CCT) for 297 light source spectra identified in IES Technical Memorandum TM-30-15 to test the assumption that higher S/P ratios demand higher CCTs. The results suggest that, for a given lamp type, there is a strong association between S/P ratio and CCT, and hence that for a given CCT only a small variation in S/P ratio is available. However, the results also suggest that a larger variation in S/P ratio is possible if the lighting designer is able to consider a change in lamp type.

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Albatayneh, Aiman, Haya Atieh, Mustafa Jaradat, Murad Al-Omary, Maha Zaquot, Adel Juaidi, Ramez Abdallah, and Francisco Manzano-Agugliaro. "The Impact of Modern Artificial Lighting on the Optimum Window-to-Wall Ratio of Residential Buildings in Jordan." Applied Sciences 11, no. 13 (June 24, 2021): 5888. http://dx.doi.org/10.3390/app11135888.

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Energy savings gained through natural lighting could be offset by the loss of energy through windows; therefore, the target of this study is to examine the effects of enhancing the efficiency of lighting systems on the optimum window-to-wall ratio (WWR) of Jordanian residential structures. This research proposes the hypothesis that the WWR of residential structures that contain artificial lighting systems with increased efficiency will be lower than buildings in which solar lighting is provided. The energy simulation tool, DesignBuilder (DesignBuilder Software Ltd, Stroud, UK) was used to simulate an intricate model showing a standard Jordanian residential building with a size of 130 m2. The study offers useful guidance regarding the optimum WWR for key decisionmakers when designing energy-efficient residential structures in the context of Jordan. By considering the balance between gains and losses in solar heat and light gain to exploit energy from solar sources with no reverse effects, while making comparisons between different WWR situations, the findings indicate that the typical WWR for residential structures in Jordan that have efficient Light Emitting Diode (LED) systems of lighting installed could be between 25% and 30%, which is lower than the highest WWR stipulated by the ASHRAE standards.

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Piovene, Chiara, Francesco Orsini, Sara Bosi, Rabab Sanoubar, Valeria Bregola, Giovanni Dinelli, and Giorgio Gianquinto. "Optimal red:blue ratio in led lighting for nutraceutical indoor horticulture." Scientia Horticulturae 193 (September 2015): 202–8. http://dx.doi.org/10.1016/j.scienta.2015.07.015.

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Liu, Suying, Chenfei Jiao, and Chong Zhu. "Tunnel Lighting Intelligent Control System Based on Ambient Light Ratio." Journal of Physics: Conference Series 1865, no. 2 (April 1, 2021): 022019. http://dx.doi.org/10.1088/1742-6596/1865/2/022019.

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Ahmed, FE, RG Mutters, and AE Hall. "Interactive Effects of High Temperature and Light Quality on Floral Bud Development in Cowpea." Functional Plant Biology 20, no. 6 (1993): 661. http://dx.doi.org/10.1071/pp9930661.

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Floral bud development of cowpea (Vigna unguiculata (L.) Walp.) is arrested by high night temperature and long days under natural sunlight, but not under all types of artificial lighting systems. The objective of this study was to determine whether floral bud development at high night temperature is influenced by the red/far red (R/FR) ratio during the day. Cowpea plants were grown in glasshouses with natural sunlight, and growth chambers having either metal halide-based (MH) or fluorescent-based (EL) lighting systems. Plants were subjected to R/FR ratios of 1.3, 1.6, or 1.9 with both lighting systems. Floral bud development was arrested by high night temperature under natural sunlight with R/FR ratio of 1.2, and under MH and FL lighting systems when the R/FR ratio was 1.3 or 1.6. High night temperature did not affect floral bud development of plants grown under MH or FL light with a R/FR ratio of 1.9 and the plants produced flowers, but pod set was inhibited at this temperature. Floral bud development and pod set of a heat-tolerant cowpea genotype were normal under high night temperature and not influenced by light quality or lighting system. Apparently, the degree to which high temperatures injure floral bud development depends on the R/FR ratio during the day, and values of 1.3 to 1.6 are required to elicit the same responses as those that occur in sunlight.

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Bruneau, Jean-François, and Denis Morin. "Standard and Nonstandard Roadway Lighting Compared with Darkness at Rural Intersections." Transportation Research Record: Journal of the Transportation Research Board 1918, no. 1 (January 2005): 116–22. http://dx.doi.org/10.1177/0361198105191800115.

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This report evaluates the safety aspects of roadway lighting at rural and near-urban three-way and four-way junctions by comparing unlit intersections with those lit with two different types of lighting: ( a) standard intersection lighting provided by the Ministère des Transports du Québec, Canada, and ( b) nonstandard lighting provided by the local municipalities. A night–day accident rate ratio was used to estimate the accident rate reduction for three categories of severity: fatal and personal injury accidents, property damage only accidents, and all accidents. Sites were selected with two sampling modes. The objective mode selected sites according to the accident thresholds, and the arbitrary mode systematically selected all sites with standard lighting. The night–day accident rate ratio was measured for 376 sites by dividing the annual average number of accidents (6,546) with an annual average traffic flow (760 billion vehicles), calculated for both night and day. The accident rate reduction, expressed as a percentage, was tested for validity with the Student's t-test at the 5% p-level. The results were split into 49 categories with 20 variables to ensure that no significant variation existed in the accident rate reduction related to a specific roadway condition or environment. Rural lighting of an intersection significantly reduced the night accident rate by 29% for nonstandard lighting and by 39% for standard lighting, in comparison with darkness. When the two sampling modes were compared, standard lighting reduced the night accident rate of nonstandard lighting by 29%, significant at the 5% p-level, when only objective data in the sampling were used.

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Albatayneh, Aiman, Adel Juaidi, Ramez Abdallah, and Francisco Manzano-Agugliaro. "Influence of the Advancement in the LED Lighting Technologies on the Optimum Windows-to-Wall Ratio of Jordanians Residential Buildings." Energies 14, no. 17 (September 1, 2021): 5446. http://dx.doi.org/10.3390/en14175446.

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Based on recent developments and the predicted future advancement of lighting technologies, researchers are now questioning the extent to which daylight is effective in lowering the overall energy consumption of buildings. As light-emitting diode (LED) luminaires are highly energy efficient, the amount of power consumed for lighting purposes can be reduced, even in situations where the lighting system is at its full power. It has already been demonstrated that LED-lighting technologies can facilitate significant energy savings through minimizing window size (the main source of heat loss in buildings), and there is considerable potential for developing the LEDs’ source efficacy and lighting-product efficiency to ultimately achieve levels of efficacy of approximately 350 lumens per Watt (lm/W). For building designs to be sustainable in the future, it is critical that the windows-to-wall ratio (WWR) is optimized to minimize both heating and cooling loads, as well as the total energy consumed by the building for lighting, according to the efficiency of the LED, while still maintaining a suitable lighting level for occupants. This research examines the influence of the WWR on the total amount of energy consumed by standard buildings in Jordan using various LED luminaires (existing and projected efficiencies). DesignBuilder software was utilized to analyze the effect of LED-technology development on optimizing the WWR for a typical residential structure in Jordan. The research presents beneficial recommendations with respect to optimizing the WWR for primary decision-makers in the design of residential buildings with enhanced energy efficiency, considering the losses and gains associated with solar heat and light to capitalize on solar energy with no adverse impacts by windows size. The outcomes suggest a WWR of 17% could be achieved by typical residential buildings in Jordan that have extremely efficient LED lighting systems (350 lm/W), which is more than 50% less than the existing level of 40% recommended by multiple standards. Additionally, this study highlighted that when the efficiency of LED technologies increases, the energy demand of the building will be reduced because of lower energy usage combined with heat gain resulting from the LED efficiency.

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Lynn, Barry H., Yoav Yair, Colin Price, Guy Kelman, and Adam J. Clark. "Predicting Cloud-to-Ground and Intracloud Lightning in Weather Forecast Models." Weather and Forecasting 27, no. 6 (December 1, 2012): 1470–88. http://dx.doi.org/10.1175/waf-d-11-00144.1.

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Abstract A new prognostic, spatially and temporally dependent variable is introduced to the Weather Research and Forecasting Model (WRF). This variable is called the potential electrical energy (Ep). It was used to predict the dynamic contribution of the grid-scale-resolved microphysical and vertical velocity fields to the production of cloud-to-ground and intracloud lightning in convection-allowing forecasts. The source of Ep is assumed to be the noninductive charge separation process involving collisions of graupel and ice particles in the presence of supercooled liquid water. The Ep dissipates when it exceeds preassigned threshold values and lightning is generated. An analysis of four case studies is presented and analyzed. On the 4-km simulation grid, a single cloud-to-ground lightning event was forecast with about equal values of probability of detection (POD) and false alarm ratio (FAR). However, when lighting was integrated onto 12-km and then 36-km grid overlays, there was a large improvement in the forecast skill, and as many as 10 cloud-to-ground lighting events were well forecast on the 36-km grid. The impact of initial conditions on forecast accuracy is briefly discussed, including an evaluation of the scheme in wintertime, when lightning activity is weaker. The dynamic algorithm forecasts are also contrasted with statistical lightning forecasts and differences are noted. The scheme is being used operationally with the Rapid Refresh (13 km) data; the skill scores in these operational runs were very good in clearly defined convective situations.

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Sun, Ching-Cherng, Shih-Hsin Ma, and Quang-Khoi Nguyen. "Advanced LED Solid-State Lighting Optics." Crystals 10, no. 9 (August 27, 2020): 758. http://dx.doi.org/10.3390/cryst10090758.

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Light-emitting diodes (LEDs) have been intensively studied for white-light lighting since their luminous efficacy exceeds 50 lm/W. Currently, the luminous efficacy of an LED light tube/bulb is almost above 100 lm/W. LED solid-state lighting (SSL) has unequivocally become the major light source in general lighting. The fact of high efficiency and other advantages of LED SSL is enough to penetrate all lighting scenarios. However, what people demand from new-generation lighting is not only in energy efficiency but also in lighting quality. Thus, how to make the lighting more user friendly is one of the important issues, and, here, optics is the key point. For making a collection with the discussions of the novel optical design in enhancing lighting efficiency in a more uniform illumination pattern, in higher sharpness for special lighting, in a higher signal-to-noise ratio for communication, in more functions for new applications, etc., this Special Issue of “Advanced LED Solid-State Lighting Optics” focuses on advanced applications in all aspects.

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Li, Hung-Chung, Pei-Li Sun, Yennun Huang, and Ming Ronnier Luo. "Spectral Optimization of White LED Based on Mesopic Luminance and Color Gamut Volume for Dim Lighting Conditions." Applied Sciences 10, no. 10 (May 21, 2020): 3579. http://dx.doi.org/10.3390/app10103579.

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The study aims to propose an approach of white LED spectral optimization based on mesopic luminance and color gamut volume for dim lighting conditions. Three optimal white LED spectra with relatively higher mesopic luminance and color gamut volume, the highest mesopic luminance, and the largest gamut volume are recommended for reducing energy consumption and enhancing color perception and recognition of human eyes. The theoretical simulation shows that the spectra with higher correlated color temperatures (CCT) and S/P-ratio increase the mesopic luminance and also extend the range of color gamut with the decreasing of lighting level. An evaluation model is developed to faster predict mesopic luminance, color gamut volume, and S/P ratio for lighting applications.

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Pronin, M. A., and E. V. Churkina. "Effect of light switch illumination on total energy consumption." Safety and Reliability of Power Industry 14, no. 2 (July 28, 2021): 151–56. http://dx.doi.org/10.24223/1999-5555-2021-14-2-151-156.

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The question of the relevance of reducing energy consumption is considered. An assumption is made that in cases where indoor illuminated switches are used that control a group of lamps, currents of the order of microamperes flow in the lighting network in the switched-off mode.The regulatory documentation related to the normative indicators of illumination as well as the typical area of premises is analyzed, and on the basis of the listed data, the calculation of the minimum required luminous flux emitted by lamps is made. The normalized calculated luminous flux was divided by the luminous flux from one lamp, with the resulting ratio rounded up. This ratio is the approximate number of lamps. This number of lamps will enable to calculate the total current of the entire lighting network.The standard rates for the operating time of the lighting network are taken into account. The operating time of the lighting network in the "standby" mode is the difference between the total number of hours per day and the standard operating time of the lighting network.Knowing the power consumption and the network operation time in the "standby" mode, we can calculate the power consumption of the lighting network in the "standby" mode.

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Ma, Bin, and Jie Sun. "The Research of Lighting Control System Based on NRF24L01 Wireless Network." Advanced Materials Research 488-489 (March 2012): 1742–46. http://dx.doi.org/10.4028/www.scientific.net/amr.488-489.1742.

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Traditional lighting has many disadvantages, such as dispersed control, energy inefficacy, which could waste much of human and material resources. With people demands of controlling light source and saving energy, intelligent lighting become realistic with the help of RF and NC technologies. This paper designs an intelligent lighting control network using nRF24L01, and the network has set up in a lighting system experiment. This network make full use of the advantage of wireless sensor networks, it can be used in a variety of control systems to solve the problem of decentralized control. Compared with the traditional control mode, it would not only improve source utilization ratio, but also make better the lighting system management.

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BATES, D. P., L. E. HANSON, M. E. COOK, B. C. WENTWORTH, M. L. SUNDE, and J. J. BITGOOD. "Lighting and Sex Ratio for Breeding Ringnecked Pheasants in Confined Housing." Poultry Science 66, no. 4 (April 1987): 605–12. http://dx.doi.org/10.3382/ps.0660605.

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Miyamoto, Manabu, Toshio Uchimaru, Hayato Ito, and Yoshinori Karasawa. "Permissible ratio of the reduced luminance for the tunnel emergency lighting." JOURNAL OF THE ILLUMINATING ENGINEERING INSTITUTE OF JAPAN 86, Appendix (2002): 110. http://dx.doi.org/10.2150/jieij1980.86.appendix_110.

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Li, Xiao Lei, Huan Li, and Jian Ping Gao. "Impact Analysis to Building Energy Consumption of Daylighting Combined Lighting Control." Applied Mechanics and Materials 260-261 (December 2012): 202–8. http://dx.doi.org/10.4028/www.scientific.net/amm.260-261.202.

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A study on the building energy consumption analysis of daylighting-based lighting control strategy was carried out. A circle type of building was mainly simulated by using the eQUEST energy simulating software. By setting various window-wall ratios, we try to find the relationship between the energy saved by daylighting-based lighting control and the other main energy consumptions, such as the cooling and heating energies. The data shows that the energy saving potential of daylighting-based lighting control strategy can be 40% under the proper window-wall ratio, and in the meanwhile, the total energy saving of the whole building can be 8%. A formula is given to get the best window-wall ratio of various cities according to its geographical information and local climate factors.

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Dong, Hai Rong, Shao Ming Qi, and Kai Xu. "Optimal Design of the Lighting Atrium Form in the Building." Applied Mechanics and Materials 744-746 (March 2015): 1579–83. http://dx.doi.org/10.4028/www.scientific.net/amm.744-746.1579.

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The unique atrium space design brings different visual perception to people, and rational atrium structure has a good influence on natural lighting and energy consumption. The lighting atrium has been widely used in public buildings. This paper aims to optimize the atrium design of public buildings. Some factors such as atrium aspect ratio, light transmission coefficient of the glass and atrium shape etc, were probed in through numerical simulation, which analyzes lighting influence of various lighting atrium forms. On this basis, this paper draws some conclusions, such as daylight factor of atrium space distribution characteristics and its relevance of atrium space geometry, proposes some optimization strategies of architectural lighting atrium, try to provide some guidance in the atrium application of public buildings.

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Türker, İsmail, Mehmet Akif Boz, Hulusi Ozan Taşkesen, and Serdar Kamanlı. "Dalgalı Aydınlatma Programının Etlik Piliçlerin Verim ve Karkas Özellikleri Üzerine Etkisi." Turkish Journal of Agriculture - Food Science and Technology 8, no. 1 (January 31, 2020): 230. http://dx.doi.org/10.24925/turjaf.v8i1.230-233.3051.

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This research was conducted for 42 days, in order to determine the effects of fluctuate lighting program on production and carcass characteristics of broiler chickens. 300 day old Ross 308 chicks were used. Chicks were randomly distributed to 2 lighting groups which were normal lighting (control) and fluctuate lighting, and each group was divided in to 3 replicates containing 50 chicks. For both groups lighting was arranged as 23 hours of lighting versus 1 hour of dimming. Control group was subjected to constant lighting of 20 lux/m2 for the days 0-21, and 5 lux/m2 for the days 22-42; while in the fluctuate lighting group was subjected to lighting of 5 lux/m2 for 45 minutes and additional 20 lux/m2 for 15 minutes every hour. There were no differences of final body weight, weekly body weight gain, cumulative feed intake, cumulative feed conversion ratio, viability, foot and leg problems, hot and cool carcass weight, thigh weight, breast weight, wing weight, back weight, liver or heart weights. However, there were statistically significant differences of gizzard weight and abdominal fat weight between two groups. In conclusion, gizzard and abdominal fat weights of broilers subjected to fluctuate lighting are less than control. This suggests that fluctuate lighting can be used to lower abdominal fat which is an important problem in broilers.

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Hwang, Taeyon, and Jeong Tai Kim. "Effects of Indoor Lighting on Occupants’ Visual Comfort and Eye Health in a Green Building." Indoor and Built Environment 20, no. 1 (December 29, 2010): 75–90. http://dx.doi.org/10.1177/1420326x10392017.

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This study investigated the effects of indoor lighting on occupants’ visual comfort and eye health and to contribute to the management and maintenance of buildings. The illuminance of the working plane and windows at Samsung Corporation Headquarters were measured, and 2744 healthy occupants of Samsung Corporation were surveyed regarding the indoor lighting environment via the company’s intranet for 1½ years. This building was certified with the highest ranking by Korea’s Green Building Council. The cumulative data reflected the management and maintenance of the building, such as screen-type shading devices automatically controlled by seasons and time, improvement of visual display terminal glare by the veiling reflection on monitors, efficiency of artificial lighting arrays, and so on. The data were analysed for occupants’ visual comfort and eye health. The result showed that daylighting could improve the occupants’ psychological health and productivity. The screen-type shading device could intercept direct sunlight and reduce annoyance glare. However, the indoor lighting and visual environment of the building were poor. After examining the questionnaire feedback concerning improvements, the occupants’ annoyance ratio was significantly reduced, and approximately 5% of the occupants’ annoyance ratio was deemed to be caused by personal characteristics related to the lighting of the environment.

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Newsham, GR, and JA Veitch. "Lighting quality recommendations for VDT offices: a new method of derivation." Lighting Research & Technology 33, no. 2 (June 2001): 97–113. http://dx.doi.org/10.1177/136578280103300205.

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An experiment in a mock-up office space gave occupants control over dimmable lighting circuits after a day working under pseudo-random lighting conditions. Data analysis indicated that the lighting experienced during the day influenced the changes in lighting made at the end of the day. Occupants chose to reduce screen glare if any existed. Even after allowing for the effect of glare, desktop illuminance at day’s end varied with the illuminance experienced during the day. Regression of these end-of-day choices relative to the illuminance experienced during the day can yield a preferred illuminance, equivalent to the daytime illuminance at which no change was preferred at day’s end. Using this method, preferred illuminances in the range 200-500 lux were derived. Preferences for luminance ratio were also derived. Interestingly, the deviation between participants’ lighting preferences and the lighting they experienced during the day was a significant predictor of participant mood and satisfaction.

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Chang, Jing Yi, Yean Der Kuan, Chih Hsun Yao, and Sheng Ching Chan. "Integrated Application of Renewable Energy Technology in Building Energy Efficiency." Applied Mechanics and Materials 193-194 (August 2012): 51–56. http://dx.doi.org/10.4028/www.scientific.net/amm.193-194.51.

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During the average fifty or sixty years of building lifecycles, large amounts of energies are consumed at all stages, from the production of building materials, transportation for project constructions, daily use, and maintenance to demolition, in particular, the daily energy consumption of air-conditioners, lighting, and elevators. The main “energy saving indicator,” from among nine green building indicators, evaluates the electrical power consumption of air conditioners and lighting. The main evaluation items are building envelope heating load ratio, air-conditioner energy efficiency ratio, and lighting energy saving ratio. During evaluation, the promotion and application of renewable energy is encouraged by incentive factors. The development and use of renewable energy technology may improve energy utilization efficiency, maintain a balance of supply and demand, and reduce environmental pollution, thus, this study developed a indoor personal office system with 1KW solar energy and a 500W proton exchange membrane fuel cell (PEM fuel cell) as the power source, which is composed of LED indoor lighting, air fan, LED table lamp, notebook computer, printer, and acoustic equipment. Under continuous operations of 24h, this office system will generate 12kwh of electricity, which reduces 7.656kg of carbon dioxide output. If continuously operated for 1 year, it will generate 4,320kwh electricity, which reduces 2,756.16kg of carbon dioxide output. In addition, the side product water can be recycled as landscape water.

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Lee, Young-Jin, Young-Seok Seo, Min-Seok Oh, and Hway-Suh Kim. "A Study on Making Upward Lighting Ratio Regulation for Lighting Zone Based on the Light Distribution of Streetlight Site Survey." Journal of the Korean Institute of Illuminating and Electrical Installation Engineers 26, no. 10 (October 31, 2012): 9–15. http://dx.doi.org/10.5207/jieie.2012.26.10.009.

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Ramdan, Iwan M., Novita Anggun P, and Ade Rahmat F. "Risk Factor of Pnemonia among Children Aged Under 5 Years. A Case Control Study in Samarinda, Indonesia." International Journal Of Medical Science And Clinical Invention 5, no. 3 (March 13, 2018): 3601–5. http://dx.doi.org/10.18535/ijmsci/v5i3.08.

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Introduction: Pneumonia is still a global health problem especially in developing countries because it is the leading cause of death in children aged under 5 years old. In Indonesia the incidence of children pnemonia is still high. Material and methods: The risk factors of pneumonia studied consist of house temperature, lighting, house humidity, occupancy density, exposure to cigarette smoke, and family disease history. Temperature and humidity of the house were measured by heatstress monitor, room lighting was measured by lux meters, the occupancy density was measured by direct observation, exposure to cigarette smoke and family disease history were measured by questionnaire. Data analysis using odds ratio and chi square. Results: Obtained by the value of odds ratio: room lighting (OR = 3.18), cigarette smoke exposure (OR = 10.45), home temperature (OR = 0.337), humidity (OR = 0.192), occupancy density (OR = 0.214), and family history of disease ( OR = 0.753). Humidity (p = 0.024) and occupancy density (p = 0.028) associated with pneumonia. Conclusion: Room lighting and exposure to cigarette smoke is a major risk factor for the occurrence of pneumonia in children aged under 5 years in Samarinda, the incidence of pneumonia is significantly related to house humidity and occupancy density.

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Deram, Paul, Mark G. Lefsrud, and Valérie Orsat. "Supplemental Lighting Orientation and Red-to-blue Ratio of Light-emitting Diodes for Greenhouse Tomato Production." HortScience 49, no. 4 (April 2014): 448–52. http://dx.doi.org/10.21273/hortsci.49.4.448.

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Current greenhouse supplemental lighting technology uses broad-spectrum high-pressure sodium lamps (HPS) that, despite being an excellent luminous source, are not the most efficient light source for plant production. Specific light frequencies in the 400- to 700-nm range have been shown to affect photosynthesis more directly than other wavelengths (especially in the red and blue ranges). Light-emitting diodes (LEDs) could diminish lighting costs as a result of their high efficiency, lower operating temperatures, and wavelength specificity. LEDs can be selected to target the wavelengths used by plants, enabling growers to customize the light produced, to enable maximum plant production and limit wavelengths that do not significantly impact plant growth. In our experiment, hydroponically grown tomato plants (Solanum lycopersicum L.) were grown using a full factorial design with three light intensities (high: 135 μmol·m−2·s−1, medium: 115 μmol·m−2·s−1, and low: 100 μmol·m−2·s−1) at three red (661 nm) to blue (449 nm) ratio levels (5:1, 10:1, and 19:1). Secondary treatments for comparison were 100% HPS, 100% red LED light supplied from above the plant, 100% red LED light supplied below the plant, a 50%:50% LED:HPS mixture, and a control (no supplemental lighting). Both runs of the experiment lasted 120 days during the Summer–Fall 2011 and the Winter–Spring 2011–12. The highest biomass production (excluding fruit) occurred with the 19:1 ratio (red to blue) with increasing intensity resulting in more growth, whereas a higher fruit production was obtained using the 5:1 ratio. The highest marketable fruit production (fruit over 90 g) was obtained with the 50%:50% LED:HPS followed by 5:1 high and 19:1 high. Consistently the 5:1 high performed well in every category. LEDs have been shown to be superior in fruit production over HPS alone, and LEDs can improve tomato fruit production when mixed with HPS. LEDs provide a promising mechanism to enhance greenhouse artificial lighting systems.

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Liu, Hailiang, Jiade Cheng, and Asnidar Hanim Yusuf. "Design of Light Emitting Diodes (LEDs) Lighting System and Its Application in Garden Landscape Decoration." Journal of Nanoelectronics and Optoelectronics 15, no. 6 (June 1, 2020): 734–42. http://dx.doi.org/10.1166/jno.2020.2793.

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Light Emitting Diode (LED) is widely used in garden landscape decoration because of its small size, low power, concentrated light, and the capability of showing more vivid colors. While designing the LED lighting system, considering that a single Advanced RISC Machine (ARM)-based control system cannot achieve large-scale LED display, and a single Field Programmable Gate Array (FPGA)-based control system cannot control the lighting system well, an LED system with the combination of ARM processor-FPGA is proposed. In this system, the ARM processor is used as the major control component. The Linux system realizes remote monitoring and intelligent management of image data. In addition, FPGA is used for LED data output. The lighting system consists of a major control node and a lighting node. The nodes are connected in parallel through a chain network. The major control node uses an ARM Cortex processor and is equipped with a Linux operating system. The lighting node uses ARM + FPGA hardware architecture. During the experiments, the LED lighting system is tested first. The results show that the reading and writing speed is fast. The LED display screen meets the lighting requirements. This LED lighting system is used for night lighting of garden landscapes. During the brightness test, the brightness of lighting objects and the background is used as research objects. Experiments have proved that the ratio of the lighting object brightness to the background brightness between (Yu, M. and Li, X., 2012. A little current k-factor method for measuring junction temperature of aviation lighting power led. Guangxue Jishu/Optical Technique, 38(3), pp.371–375; Monas, A., Verma, A., Gawari, A. and Paswan, R. S., 2016. Portable network monitor using arm processor. Procedia Computer Science, 92, pp.493–497.) is suitable for night lighting of garden landscape decoration, which will not bring discomfort to people who enjoy night scenery.

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Goswamy, Amrita, Shauna Hallmark, Theresa Litteral, and Michael Pawlovich. "Safety Evaluation of Destination Lighting Treatment at Stop Controlled Cross-Intersections." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 16 (May 23, 2018): 113–21. http://dx.doi.org/10.1177/0361198118774747.

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Intersection crashes during nighttime hours may occur because of poor driver visual cognition of conflicting traffic or intersection presence. In rural areas, the only source of lighting is typically provided by vehicle headlights. Roadway lighting enhances driver recognition of intersection presence and visibility of signs and markings. Destination lighting provides some illumination for the intersection but is not intended to fully illuminate all approaches. Destination lighting has been widely used in Iowa but the effectiveness has not been well documented. This study, therefore, sought to evaluate the effect on safety of destination lighting at rural intersections. As part of an extensive data collection effort, locations with destination/street lighting were gathered with the assistance of several state agencies. After manual selection of a similar number of control intersections, propensity score matching using the caliper width technique was used to match 245 treatments with 245 control sites. Negative binomial regression was used to evaluate crash frequency data. The presence of destination lighting at stop-controlled cross-intersections generally reduced the night-to-day crash ratio by 19%. The presence of treatment or destination lighting was associated with a 33%–39% increase in daytime crashes across all models but was associated with an 18%–33% reduction in nighttime crashes. Injuries in nighttime crashes decreased by 24% and total nighttime crashes reduced by 33%. Property damage crashes were reduced by 18%.

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Jin, Shou Feng, Yong Biao Hu, and Ming Rui Tian. "The Correction Methods of Morphology on Uneven Lighting Pavement Image." Applied Mechanics and Materials 331 (July 2013): 286–89. http://dx.doi.org/10.4028/www.scientific.net/amm.331.286.

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The pavement image collected under the natural light, often exist the uneven background grayscale , it affects the subsequent image processing. For this reason, this paper puts forward an image correction method that is based on the morphology. The method get the uneven background light image through the morphology opening operation for the original image , then subtracting the background from the original image and eliminate the influence of the uneven background. Due to the difference image has the low contrast ratio, this paper improves the contrast ratio of the difference image by the contrast enhancement algorithm. Experimental results show that the method can correction the uneven lighting image , and improve the contrast ratio of the image. The Project was Supported by the Special Fund for Basic Scientific Research of Central Colleges,Chang'an University (CHD2010ZY011)

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Sambandam Raju, Preethi, Murugan Mahalingam, and Revathi Arumugam Rajendran. "Design, Implementation and Power Analysis of Pervasive Adaptive Resourceful Smart Lighting and Alerting Devices in Developing Countries Supporting Incandescent and LED Light Bulbs." Sensors 19, no. 9 (April 30, 2019): 2032. http://dx.doi.org/10.3390/s19092032.

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Nowadays, there is an increasing demand for energy saving techniques in residential, industrial, institutional, clinical and other multipurpose indoor and outdoor applications. Lights play an ubiquitous role around the Earth in all types of structures and outdoor surroundings. Hence, the authors propose a universal lighting control device—named Pervasive Adaptive Resourceful Smart Lighting and Alerting Device—accomplished mainly by the use of Arduino UNO R3. The Pervasive Adaptive Resourceful Smart Lighting and Alerting Device works in two modes, namely, light control and alert, by deploying the perceptive light automation and perceptive light automation with buzzer activation algorithms, respectively. The contributions of the paper are: a common lighting control solution for both incandescent and light emitting diode light bulbs for all indoor and outdoor environments. A profound power consumption analysis, and investigation of the proposed device by estimating the Energy Consumption Ratio (ECR) and Relative Energy Saving Ratio (RESR) through the real time deployment in diverse circumstances with 60 W incandescent, 8 W and 0.5 W LED light bulbs is executed. In addition to the evaluation of RESR and ECR characteristics the power consumption of light bulbs in terms of scalable conditions of number of light bulbs is also analyzed. The proposed model is proved to work efficiently for both incandescent and LED light bulbs.

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Ixtaina, Pablo, Alejandro Armas, Braian Bannert, and Nicolás Bufo. "Argentinean Experience in Highways Led Lighting." Energy and Environment Research 7, no. 1 (May 27, 2017): 31. http://dx.doi.org/10.5539/eer.v7n1p31.

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The impact of led luminaries on road lighting has modified traditional design patterns. The technological change proposes an installation with a higher prime cost and less energy consumption. On the one hand, the price ratio between led luminary and traditional luminary is at least 3:1. On the other, the led better energetic efficiency could allow keeping proper illumination levels with less installed power. In this frame, since mid 2013, the road concessionaires of highways which constitute the Access Network to Buenos Aires city (Argentina), together with Urban Highways of the mentioned city, began a restructuring process of their lighting systems to led technology. Framed in a review of efficiency concepts and energetic classification for road lighting installations, the work presents the main results of the previous evaluation tests and of the reconverted installations, which can be considered as the first led applications at large scale on road lighting of the region.

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Djuretic, A., V. Skerovic, N. Arsic, and M. Kostic. "Luminous flux to input power ratio, power factor and harmonics when dimming high-pressure sodium and LED luminaires used in road lighting." Lighting Research & Technology 51, no. 2 (May 29, 2018): 304–23. http://dx.doi.org/10.1177/1477153518777272.

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This paper presents experimentally obtained luminous flux to input power characteristics of high-pressure sodium and LED luminaires used in road lighting, confirming that when applying dimming scenarios more percentage energy savings can be achieved by an LED than by a corresponding high-pressure sodium lighting installation. However, both workshop and field experiments showed that the tested LED drivers (of either standard or improved dimming characteristics) have the disadvantage of poor power factors (down to 0.67) at low light levels achieved by dimming. In addition, an increased presence of current harmonics and high values of the current total harmonic distortion were noticed at low light levels, representing another serious disadvantage of LED technology regarding power quality. The relevant electrical characteristics of commonly used LED drivers were analysed in detail and the reasons for the poor power quality when dimming LED luminaires were recognised. A new generation of LED drivers with a considerably narrower range of input (AC) voltage will allow acceptable power factors and limited emissions of current harmonics to be achieved in practically all lighting regimes.

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MAEDA, Noriaki, and Kei KAWAMURA. "A PROPOSAL OF EFFECTIVE REPAIR METHOD CONSIDERING REPAIR RATIO IN TUNNEL LIGHTING FACILITIES." Journal of Japan Society of Civil Engineers, Ser. F3 (Civil Engineering Informatics) 75, no. 2 (2019): I_30—I_39. http://dx.doi.org/10.2208/jscejcei.75.2_i_30.

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Tani, Yusuke, Ryo Nishijima, Takehiro Nagai, Kowa Koida, Michiteru Kitazaki, and Shigeki Nakauchi. "Change of Translucency Perception with Lighting Intensity Ratio Between Front and Back Illuminations." Journal of The Institute of Image Information and Television Engineers 68, no. 12 (2014): J534—J536. http://dx.doi.org/10.3169/itej.68.j534.

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Pennisi, G., A. Pistillo, F. Orsini, G. Gianquinto, J. A. Fernandez, A. Crepaldi, and S. Nicola. "Improved red and blue ratio in LED lighting for indoor cultivation of basil." Acta Horticulturae, no. 1271 (February 2020): 115–18. http://dx.doi.org/10.17660/actahortic.2020.1271.16.

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Ivan, K., I. Haidu, J. Benedek, and S. M. Ciobanu. "Identification of traffic accident risk-prone areas under low lighting conditions." Natural Hazards and Earth System Sciences Discussions 3, no. 2 (February 17, 2015): 1453–72. http://dx.doi.org/10.5194/nhessd-3-1453-2015.

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Abstract. Besides other non-behavioural factors, the low lighting conditions significantly influence the frequency of the traffic accidents in the urban environment. This paper intends to identify the impact of low lighting conditions on the traffic accidents in the city of Cluj-Napoca. The dependence degree between lighting and the number of traffic accidents was analyzed by the Pearson's correlation and the relation between the spatial distribution of traffic accidents and the lighting conditions was determined by the frequency ratio model. The vulnerable areas within the city were identified based on the calculation of the injured persons rate for the 0.5 km2 equally-sized areas uniformly distributed within the study area. The results have shown a strong linear dependence between the low lighting conditions and the number of traffic accidents in terms of three seasonal variations and a high probability of traffic accidents occurrence under the above-mentioned conditions, at the city entrances-exits, which represent also vulnerable areas within the study area. Knowing the linear dependence and the spatial relation between the low lighting and the number of traffic accidents, as well as the consequences induced by their occurrence enabled us to identify the high traffic accident risk areas in the city of Cluj-Napoca.

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Yehorchenkov, Volodymyr, Oleh Sergeychuk, and Lidiia Koval. "Principles of the exposure natural lighting modeling of premises." Theory and Building Practice 2020, no. 2 (November 20, 2020): 113–18. http://dx.doi.org/10.23939/jtbp2020.02.113.

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It’s well known that a criterion of estimating the varying natural lighting is exposure equal to the product of light intensity by its duration. Here we have made studies into the exposure in the room depending on the orientation of a light aperture and its location in space. The exposure has been considered by the example of three identical office rooms with the same light apertures oriented north, west and south and having three positions – vertical, inclined and horizontal. To calculate the annual exposure we made use of the well-known software package VELUX Daylight Visualizer 2. For convenience of analyzing the exposure there was introduced the concept of the natural exposure coefficient (NEC) which is a ratio between the exposure in the room and a simultaneous value of the outer exposure. Our studies have shown that exposure is an effective criterion to assess the indoor natural lighting in time. The existing system of estimating energy consumption in lighting buildings with the help of a simultaneous lighting is rough and does not take into account such factors as orientation of light apertures by the sides of the horizon and their location in space. The use of exposure let us improve the method of calculating energy consumption in lighting premises taking into account the light aperture location in space and their as orientation by the sides of the horizon. The numerical experiment performed has given a predicted result, namely, the most power-consuming room is the north-oriented one with the vertical light aperture and the least power-consuming room is the one with the horizontal light aperture. The room with the inclined light aperture has average energy consumption.

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Jiang, Jun, Mehrdad Moallem, and Youbin Zhengi. "An Intelligent IoT-enabled Lighting System for Energy-efficient Crop Production." Journal of Daylighting 8, no. 1 (February 15, 2021): 86–99. http://dx.doi.org/10.15627/jd.2021.6.

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In this paper, an intelligent lighting instrumentation and automation system is presented with the objective of achieving high energy-efficiency in greenhouse supplemental lighting based on the Internet of Things (IoT) technology. The system runs on a Raspbian operating system which interacts with wireless-enabled light emitting diode (LED) fixtures for plant growth, an online data server, and different light sensors including RGB and quantum sensors. The communication is achieved through RestFul API, UART, and I2C. The system is utilized to implement a feedback controller that automatically adjusts the light dimming levels and, in particular, the ratio of red and blue light intensities based on the plants’ needs. A series of experiments involving plant growth were conducted which indicate that the proposed system can achieve energy-savings up to 34%, when compared to a conventional time scheduling scheme. Additionally, the experiments demonstrate that the system can achieve a highly uniform light distribution under unpredictable natural lighting conditions while saving energy due to supplemental lighting.

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Perkins, Chloe, Rebecca Steinbach, Lisa Tompson, Judith Green, Shane Johnson, Chris Grundy, Paul Wilkinson, and Phil Edwards. "What is the effect of reduced street lighting on crime and road traffic injuries at night? A mixed-methods study." Public Health Research 3, no. 11 (September 2015): 1–108. http://dx.doi.org/10.3310/phr03110.

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BackgroundSome local authorities have reduced street lighting at night to save energy, but little is known about impacts on public health or about public concerns about impacts on well-being.AimTo evaluate the effect of reduced street lighting on crime and road traffic injuries.DesignA mixed-methods study comprising a rapid appraisal, a controlled interrupted time series analysis and a cost–benefit analysis (CBA).SettingEngland and Wales.Target populationResidents and workers in eight case study areas; road traffic casualties and victims of crime.Interventions evaluatedSwitch-off (i.e. lights permanently turned off), part-night lighting (e.g. lights switched off between 12 a.m. and 6 a.m.), dimming lights and white lights/light-emitting diodes (LEDs).OutcomesPublic views about implications on well-being; road traffic injury data (STATS19:http://data.gov.uk/dataset/road-accidents-safety-data) obtained for the period 2000–13; crime data (Police.uk:data.police.uk) obtained for the period December 2010–December 2013. Detailed crime data were obtained from one police force for a methodological study of the spatial level at which Police.uk data are valid for analysis.Statistical methodsRoad traffic collisions were analysed at street segment level. Regression models were used to estimate changes in daytime and night-time collision rates associated with lighting interventions. The ratio of night-time and daytime changes was considered the best estimate of change in night-time collisions following each lighting intervention. Police.uk crime data were found to be reliable when analysed at middle super output area (MSOA) level. For crime, the analysis used the proportion of total km of road in each MSOA with each lighting intervention. Regression models controlled for yearly and monthly trends and were fitted in each geographical region and police force. Effect estimates were pooled in random-effects meta-analyses.ResultsPublic concerns centred on personal security, road safety, crime, fear of crime, sleep quality and being able to see the night sky. Street lighting reductions went largely unnoticed or had only marginal impacts on well-being, but for a minority of people switch-off and part-night lighting elicited concerns about fear of the dark, modernity and local governance. Street lighting data were obtained from 62 local authorities. There was no evidence that reduced street lighting was associated with road traffic collisions at night. There was significant heterogeneity in the estimated effects on crime at police force level. Overall, there was no evidence that reduced street lighting was associated with crime. There was weak evidence for a reduction in crime associated with dimming [rate ratio (RR) 0.84, 95% confidence interval (CI) 0.70 to 1.02] and white light (RR 0.89, 95% CI 0.77 to 1.03). The CBA suggests that part-night lighting may represent a net benefit to local authorities.LimitationsThe study did not account for the impacts of other safety/crime prevention initiatives (e.g. improved road markings; closed-circuit television), and so associations may be partly attributable to these initiatives. The CBA was unable to include potentially important impacts such as fear of crime and reduced mobility.ConclusionThis study found little evidence of harmful effects of switch-off, part-night lighting, dimming or changes to white light/LEDs on levels of road traffic collisions or crime in England and Wales. However, the public were also concerned about other health outcomes. Research is needed to understand how lighting affects opportunities for crime prevention and how these vary by context. Research is needed also on other public health impacts of light at night.FundingThe National Institute for Health Research Public Health Research programme.

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Gbologah, Franklin E., Angshuman Guin, Roger Purcell, and Michael O. Rodgers. "Benefit-to-Cost Analysis Framework for Intersection Illumination: A Case Study of Rural Conventional Intersections in Georgia." Transportation Research Record: Journal of the Transportation Research Board 2673, no. 9 (May 4, 2019): 83–93. http://dx.doi.org/10.1177/0361198119843262.

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Lighting provides one of the most effective night-time intersection safety countermeasures. However, lighting is also one of the main contributors to intersection maintenance and operation costs. For a public transportation agency with jurisdiction over many intersections, the system-wide lighting costs can significantly deplete already limited funds for other important maintenance projects. A sound framework for conducting benefit-to-cost trade-off analysis would be beneficial to transportation agencies. Unfortunately, published works on the benefit-to-cost analysis are few and mostly dated. This paper outlines a detailed framework for conducting benefit-to-cost analysis for rural intersection lighting. The framework uses intersection lighting simulation models to generate annualized operating and maintenance cost data for different lighting levels. The intersection lighting models were developed with DIALux® professional lighting software. This study used the framework to conduct a case study of rural conventional three-leg and four-leg intersections with at least an annual average daily traffic (AADT) of 500 from Georgia. Based on the available Georgia case study data, this paper finds that for rural intersection locations that require no electrification, basically any illumination level, including those less than the recommended minimum of 8 lux, is likely to be cost-effective for any entering AADT. However, locations that require electrification need to be evaluated based on the overall costs, entering AADT, existing crash rate, and a target benefit-to-cost ratio that signifies the level of cost-effectiveness required by the state Department of Transport (DOT). Consequently, a companion spreadsheet benefit-to-cost model has been developed to facilitate the cost-effectiveness analysis at any rural uncontrolled or stop-controlled intersection.

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Chiesa, Giacomo, Andrea Acquaviva, Mario Grosso, Lorenzo Bottaccioli, Maurizio Floridia, Edoardo Pristeri, and Edoardo Sanna. "Parametric Optimization of Window-to-Wall Ratio for Passive Buildings Adopting A Scripting Methodology to Dynamic-Energy Simulation." Sustainability 11, no. 11 (May 31, 2019): 3078. http://dx.doi.org/10.3390/su11113078.

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Counterbalancing climate change is one of the biggest challenges for engineers around the world. One of the areas in which optimization techniques can be used to reduce energy needs, and with that the pollution derived from its production, is building design. With this study of a generic office located both in a northern country and in a temperate/Mediterranean site, we want to introduce a coding approach to dynamic energy simulation, able to suggest, from the early-design phases when the main building forms are defined, optimal configurations considering the energy needs for heating, cooling and lighting. Generally, early-design considerations of energy need reduction focus on the winter season only, in line with the current regulations; nevertheless a more holistic approach is needed to include other high consumption voices, e.g., for space cooling and lighting. The main considered design parameter is the WWR (window-to-wall ratio), even if further variables are considered in a set of parallel analyses (level of insulation, orientation, activation of low-cooling strategies including shading devices and ventilative cooling). Finally, the effect of different levels of occupancy was included in the analysis to regress results and compare the WWR with corresponding heating and cooling needs. This approach is adapted to Passivhaus design optimization, working on energy need minimisation acting on envelope design choices. The results demonstrate that it is essential to include, from the early-design configurations, a larger set of variables in order to optimize the expected energy needs on the basis of different aspects (cooling, heating, lighting, design choices). Coding is performed using Python scripting, while dynamic energy simulations are based on EnergyPlus.

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Both, Arend-Jan, Bruce Bugbee, Chieri Kubota, Roberto G. Lopez, Cary Mitchell, Erik S. Runkle, and Claude Wallace. "Proposed Product Label for Electric Lamps Used in the Plant Sciences." HortTechnology 27, no. 4 (August 2017): 544–49. http://dx.doi.org/10.21273/horttech03648-16.

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Electric lamps are widely used to supplement sunlight (supplemental lighting) and daylength extension (photoperiodic lighting) for the production of horticultural crops in greenhouses and controlled environments. Recent advances in light-emitting diode (LED) technology now provide the horticultural industry with multiple lighting options. However, growers are unable to compare technologies and LED options because of insufficient data on lamp performance metrics. Here, we propose a standardized product label that facilitates the comparison of lamps across manufacturers. This label includes the photosynthetically active radiation (PAR) efficacy, PAR conversion efficiency, photon flux density output in key wave bands, as well as the phytochrome photostationary state (PSS), red/far red ratio, and graphs of the normalized photon flux density across the 300–900 nm wave band and a horizontal distribution of the light output.

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Nikanovich, T. V., Yu V. Trofimov, and M. I. Barkun. "The impact of LED lightning on the content of photosynthetic pigments in tomato leaves." Vegetable crops of Russia, no. 1 (March 5, 2021): 117–20. http://dx.doi.org/10.18619/2072-9146-2021-1-117-120.

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Relevance and methods. We studied the influence of LED lighting of different spectral composition on the content of photosynthetic pigments in tomato leaves to identify the most optimal lighting option suitable for obtaining high-quality seedlings under controlled conditions. We used LED lamps in which the ratio of the photon flux density (PFD) of the orange-red band (607–694 nm) to the PFD of the blue band (400–495 nm) varied from 1 to 20. In this case, the proportion of the PFD in the range 580-607 nm ( yellow) ranged from 13 to 22%, and the fraction of photons in the range 495–580 nm (green) ranged from 18 to 38%. The research was carried out with two varieties of Belarusian tomato varieties, which differed in a number of morphobiological characteristics.Results. It was found that the use of LED lighting of different spectral composition had mainly an inhibitory effect on the biosynthesis of chlorophylls and carotenoids in the leaf tissue of plants. The decrease in the amount of pigments, in comparison with the control variant, reached 47-57%. It was revealed that under all studied lighting options, with the exception of conditions where the spectral ratio R / B ("red/blue") was 0.8, the value of the total inhibitory effect in the Cherry Coral variety was 1.2-1.7 times lower than that of the Zorka variety, which indicated a significantly lower susceptibility of the pigment fund of the former to LED lighting. The smallest inhibitory effect of the latter on the biosynthesis of photosynthetic pigments in both tomato varieties was established at a photon flux of 69.1 μmol/s, while the greatest, exceeding it by 3.0-3.1 times in the Zorka variety and 4.5-5.3 times for the Cherry Coral variety with a photon flux of 73.9 μmol/s.

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Li, Shu Fang. "The Research on the Application of Two Kinds of Light Sources in the Training Venue for Physical Education of Universities." Advanced Materials Research 430-432 (January 2012): 1786–90. http://dx.doi.org/10.4028/www.scientific.net/amr.430-432.1786.

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The energy efficiency experiment of electric light is implemented according to the lighting design of the physical training venues. In the experiment, the corresponding illumination, power and energy efficiency ratio of the commonly used high pressure sodium lamp and metal halide lamp which work under the voltage ranging from 187V to 234V are experimentally measured and the lighting effect characteristics of the two kinds of electric light sources compared, proving that the high pressure sodium light source should be employed in the training venue for physical education of universities.

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Yahiaoui, A. "Modelling and hybrid control of building lighting systems." Lighting Research & Technology 50, no. 8 (July 23, 2017): 1225–48. http://dx.doi.org/10.1177/1477153517712781.

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The development of an accurate control system for shading devices, essentially motorised Venetian blinds, relies on the rational use of daylight in buildings. This study proposes a control strategy for building lighting components, both daylighting and artificial lighting, to automatically adjust the light level in an office building as required and to block direct sunlight from entering the office, when necessary. The proposed control strategy is based on a hybrid statecharts model mainly consisting of a supervisory control system that chooses appropriate control actions for a current sky condition depending on the sky ratio and clearness index. These control actions are implemented to automatically adjust the blind height and slat angle, and turn on the artificial lighting only when needed. Real experiments in a test-cell demonstrate the effectiveness and flexibility of the proposed control strategy.

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Lin, Kuan-Han, Chien-Chia Su, Yen-Yuan Chen, and Po-Ching Chu. "The Effects of Lighting Problems on Eye Symptoms among Cleanroom Microscope Workers." International Journal of Environmental Research and Public Health 16, no. 1 (January 1, 2019): 101. http://dx.doi.org/10.3390/ijerph16010101.

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The visual health of microscope workers is an important occupational health concern, and a previous study suggested an association between lighting problems (e.g., flashing light, insufficient lighting) and eye symptoms among cleanroom workers in the electronics industry. This study aimed to explore the association between eye symptoms and lighting problems, as well as light-related counteracting behaviors among microscope workers in the cleanroom environment. Ninety-one cleanroom workers aged 20 years or older were recruited from an electronics factory. The socio-demographic factors, work-related factors, eye symptoms, and lighting problems were assessed using a self-administered questionnaire. There were 92.3% female participants in this study. Among all participants, 41.8% and 63.7% had symptoms of dry eye and eye fatigue, respectively. The counteracting behaviors of needing to move closer (adjusted odds ratio (aOR) = 3.47, 95% CI = 1.11 to 10.88) was significantly associated with dry eye symptoms. Workers who were more experienced at the job (aOR = 1.03, 95% CI = 1.01 to 1.06) and had shorter break times (aOR = 0.94, 95% CI = 0.91 to 0.98) were more likely to have eye fatigue. As a result of these findings, this study suggests that good lighting and adequate break times are crucial to improve the visual health of cleanroom microscope workers.

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Journal articles on the topic 'Lighting ratio'

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