Comparative Evaluation of Light-Emitting Diode Cap Lamps With an Emphasis on Visual Performance in Mesopic Lighting Conditions

2014 ◽  
Vol 50 (1) ◽  
pp. 127-133 ◽  
Author(s):  
Miguel A. Reyes ◽  
John J. Sammarco ◽  
Sean Gallagher ◽  
Justin R. Srednicki
2019 ◽  
Vol 52 (2) ◽  
pp. 167-188 ◽  
Author(s):  
C Jarboe ◽  
J Snyder ◽  
MG Figueiro

Architectural lighting has traditionally addressed visual performance and horizontal illuminance on the work plane, later focussing on energy efficiency, while only recently paying particular regard to human health outcomes. The present study evaluated the effectiveness of several light-emitting diode lighting strategies for delivering circadian stimulus to occupants of a typical office space while minimizing energy use. The study employed photometric simulations in a typical open-office space, delivering a criterion circadian stimulus of 0.3 to calculation points modelled at the simulated occupants’ eye level. Six luminaire types, two luminous intensity distributions, six spectral power distributions and two horizontal illuminances were evaluated, resulting in 144 unique lighting conditions. Additionally, the study calculated the discomfort glare for selected luminaires with the highest total lumen output, smallest aperture and direct-only luminous intensity distributions at the higher of the two horizontal illuminances (500 lx). The most impactful strategy involved supplementing common overhead lighting with a desktop luminaire delivering light directly to the simulated office occupants’ eyes, which provided greater circadian stimulus and used less energy than overhead luminaires that were capable of delivering the criterion circadian stimulus of 0.3.


2019 ◽  
Vol 82 (3) ◽  
pp. 528-534 ◽  
Author(s):  
CURTIS MAUGHAN ◽  
EDGAR CHAMBERS IV ◽  
SANDRIA GODWIN ◽  
DELORES CHAMBERS

ABSTRACT Undercooked poultry is a potential source of foodborne pathogens, such as Salmonella and Campylobacter. The best way to avoid eating undercooked poultry is to use a food thermometer during cooking. However, consumers who cook poultry often use visual appearance for determining doneness, which relies on extrinsic factors, including lighting conditions. Because the United States recently mandated changes in lighting to promote energy conservation, this study evaluated the effect of lighting sources on consumer perceptions of doneness and willingness to eat cooked poultry patties. Consumers (n = 104) evaluated validated photographs of turkey patties cooked to different end point temperatures (57 to 79°C) and rated the level of perceived doneness and willingness to eat each sample. Evaluations were conducted under different lighting sources: incandescent (60 W, soft white), halogen (43 W, soft white), compact fluorescent lamp (13 W, soft white), light-emitting diode (LED; 10.5 W, soft white), and daylight LED (14 W). Lighting changed perception of doneness and willingness to eat the patties, with some of the energy-efficient options, such as LED and halogen making samples appear more done than they actually were, increasing the willingness to eat undercooked samples. This poses a risk of consuming meat that could contain bacteria not killed by heat treatment. Recent changes in lighting regulations can affect lighting in homes that affects perceptions of poultry doneness, requiring that educators place extra emphasis on the message that properly using a meat thermometer is the only way to ensure meat is cooked to a safe end point temperature.


Author(s):  
Trina Merrick ◽  
Ralf Bennartz ◽  
Maria Luisa S. P. Jorge ◽  
Thiago S. F. Silva ◽  
John Rausch ◽  
...  

In this study, we evaluated chlorophyll fluorescence (CF) under two extreme illumination conditions at plant scale with a passive spectroradiometer. Fluorescence (F) was estimated by reading directly from radiance spectra of a variety of plants illuminated with light-emitting diode (LED) grow lights in the laboratory. Solar-induced fluorescence (SIF) was estimated from spectral measurements of the same plants under sunlight using the Fraunhofer Line Depth (FLD) method. Chlorophyll fluorescence yield (Fyield) and solar-induced fluorescence yield (SIFyield) were calculated by normalizing F and SIF with absorbed photosynthetically active radiation (APAR). Two approaches to estimating APAR were compared: utilizing white reference spectra and reflected spectra versus white reference spectra combined with the fraction of absorbed photosynthetically active radiation (fPAR) derived from literature. Average F and SIF were different by a factor of approximately twenty-four (F = 0.110 ± 0.038 Wm−2μm−1sr−1 versus SIF = 2.60 ± 1.87 Wm−2μm−1sr−1). In contrast, the average normalized values Fyield and SIFyield were within the margin of error of one another (Fyield = 0.022 ± 0.008 μm−1sr−1 and SIFyield = 0.030 ± 0.020 μm−1sr−1). This study highlights the influence of APAR on CF and the importance of properly accounting for it when estimating yield and demonstrates the ability of two simple and portable experimental setups with a passive instrument to obtain fluorescence metrics.


2021 ◽  
Author(s):  
David Maria Tobaldi ◽  
Dana Dvoranová ◽  
Luc Lajaunie ◽  
Kristina Czikhardtová ◽  
Bruno Figueiredo ◽  
...  

Modern life-style is creating an indoor generation: human beings spend approximately 90% of their time indoors, almost 70% of which is at home – this trend is now exacerbated by the lockdowns/restrictions imposed due to the COVID-19 pandemic. That large amount of time spent indoors may have negative consequences on health and well-being. Indeed, poor indoor air quality is linked to a condition known as sick building syndrome. Therefore, breathing the freshest air possible it is of outmost importance. Still, due to reduced ventilation rates, indoor air quality can be considerably worse than outdoor. HVAC, air filtration systems and a well-ventilated space are a partial answer. However, these approaches involve only a physical removal. Photocatalytic mineralisation of pollutants into non-hazardous, or at least less dangerous compounds, is a more viable solution for their removal. Titanium dioxide, the archetype photocatalytic material, needs UVA light to be “activated”. However, modern household light emitting diode lamps irradiate only in the visible region of the solar spectrum. In this short-communication, we show that the surface of titanium dioxide nanoparticles modified with copper oxide(s) and graphene shows promise as a viable way to remove gaseous pollutants (benzene and NOx) by using a common light emitting diode bulb, mimicking real indoor lighting conditions. Titanium dioxide, modified with 1 mol% CuxO and 1 wt% graphene, proved to have a stable photocatalytic degradation rate, three times higher than that of unmodified titania. Materials produced in this research work are thus strong candidates for offering a safer indoor environment.


2021 ◽  
pp. 11-18
Author(s):  
Olga E. Zheleznikova ◽  
Lyudmila V. Sinitsyna ◽  
Sergey N. Ageev ◽  
Ivan V. Blentsov

The article is devoted to the description of experimental studies on the assessment of the hygienic efficiency of lighting conditions with light emitting diodes (LEDs) of the first and second generations when performing industrial work. In the course of the research work, an experimental lighting installation (ELI) was developed and installed, able to implement lighting options with LEDs and fluorescent lamps (FL). The state of the accommodative-muscular apparatus, the retina and the central link of the organ of vision was assessed; integral indicators of visual performance were studied. It was found that the illumination with LEDs does not have a negative effect on the organ of vision, the human body as a whole or indicators of visual performance. Changes in the functional indicators of the organ of vision occurring during the performance of visual work are within the corresponding boundaries of physiological fluctuations and are reversible. It was revealed that second generation LEDs create a more favourable light environment for performing visual work of a production nature. The practical significance of the results obtained was shown.


2018 ◽  
Vol 72 ◽  
pp. 01005
Author(s):  
Suntiti Yoomak ◽  
Atthapol Ngaopitakkul

This paper presents analysis of lighting quality in different road surface conditions using the DIALux software. Dry and wet road surfaces are used to study lighting quality by following classifications of the International Commission on Illumination (CIE). Lighting quality of high pressure sodium (HPS) and light emitting diode (LED) luminaires are compared, based on roadway with a traffic island. Results indicate that the HPS luminaire can provide better average illuminance and average luminance values than the LED luminaire, resulting in positive visual performance. However, the LED luminaire can achieve visual and comfort performance including energy saving due to its light distribution efficiency. For lighting quality on different road surface conditions, the lighter dry road surface materials, the higher lighting quality. Wet road surfaces cause very bright areas on road surface alternating with large dark areas. It results in the average luminance of the surface increased while overall uniformity decreased.


2019 ◽  
Vol 52 (1) ◽  
pp. 36-63
Author(s):  
L Bellia ◽  
F Fragliasso ◽  
E Stefanizzi

This paper presents an experiment on the effect of light on the perception of paintings. The experiment was performed in a test-room where a typical museum exhibition set-up was simulated. Two different paintings were shown to 44 participants, under different light scenes obtained by using tuneable LED (Light Emitting Diode) wallwashers. To set the light scenes, the following parameters were modified: correlated colour temperature of the lighting, illuminance on the painting and the colour of the background wall. Participants answered a questionnaire to assess the perception of the paintings’ colours, the lighting conditions and the pleasantness of the exhibition set-up. The results demonstrated that illuminance is the parameter mainly affecting perception, for both paintings. However, correlated colour temperature and wall colour, as well as the combination of the three different considered parameters, can more or less influence perception depending on the chromatic composition of the painting.


2016 ◽  
Vol 49 (10) ◽  
pp. 1105-1127 ◽  
Author(s):  
Julia Maier ◽  
Oliver Zierke ◽  
Hans-Juergen Hoermann ◽  
Ivan Windemut

Lighting in passenger rail cars is designed according to defined standards to implement a safe and healthy as well as comfortable lighting situation for the passengers. However, not every passenger’s demands are met by average lighting conditions; individual preferences are well-known to influence participants’ comfort sensations. To further explain the role of individual preferences and expectations regarded as stable dispositions, sensations of 40 participants were analyzed in a mock-up of a passenger rail car of the Next Generation Train (NGT) using an organic light-emitting diode (OLED) luminaire. Two lighting scenarios (100 lx and 150 lx) were used as levels of the independent variable. Results confirm that individual preferences and expectations have an influence on the perception and evaluation of the lighting situation. Moreover, positive expectations were found to have a somewhat higher impact for subjective reactions than illuminance had and should thus be considered in future lighting research and design.


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