scholarly journals 0030 Effect of a Simulated Sunset versus Typical Indoor Lighting on Evening Melatonin Levels

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A12-A12
Author(s):  
S M Lanza ◽  
B C Kindel ◽  
K E Sprecher ◽  
M M Trainer ◽  
K P Wright
Keyword(s):  
Circadian Clock ◽  
Light Emitting Diode ◽  
Least Square ◽  
Spectral Irradiance ◽  
Lighting Condition ◽  
Light Emitting ◽  
Least Square Fit ◽  
Sleep Schedule ◽  
Indoor Lighting ◽  
Endogenous Melatonin

Abstract Introduction The human circadian clock evolved in the presence of the natural light-dark solar cycle. Exposure to artificial light at night suppresses endogenous melatonin levels and delays the timing of the circadian clock. The advent of tunable LED (light emitting diode) technology presents an opportunity to develop and implement circadian based practices for healthy lighting. Here we determined the influence of a simulated sunset with tunable LED technology on evening melatonin levels. Methods Nine healthy adults (3 females, 24.0 ± 5.3 years) completed a 15-day crossover study comparing typical artificial indoor lighting versus a simulated sunset using tunable LEDs (Acuity Brands-Rubik). After 1 week maintaining an ~8h sleep schedule, participants arrived at the laboratory 6h prior to habitual bedtime. Typical electrical indoor home lighting was <90 lux in angle of gaze until scheduled bedtime (<467 lux maximum at 183 cm in the direction of the ceiling mounted light fixtures; 3,500K). To simulate sunset, a simple least square fit was used to match relative spectral irradiance of the laboratory LED lighting to solar spectral irradiance of a standard mid-latitude summer atmosphere in Boulder, Colorado with solar elevation angles ranging from 3.9 degrees to 0 degrees (sunset). The first 3h30min of the simulation was typical indoor lighting of <90 lux (angle of gaze; 3,500K) followed by a 25 min transition in spectral irradiance and then 2h5min at ~7 lux in the angle of gaze (<38 lux maximum at 183 cm; 2,700K). Results Melatonin levels were initially similar between conditions but were significantly higher (p<0.05) after the sunset transition in the simulated sunset condition compared to the typical electrical indoor home lighting condition. Conclusion These preliminary findings suggest that simulating a sunset transition with tunable LED technology prior to habitual bedtime in the evening has potential to benefit circadian health. Support This work was supported in part by NIH R01 HL135598 and NASA Award 80NSSC17K0569.

A simple design of uniform LED illumination using catadioptric collimator and freeform lenslet array

2021 ◽  
pp. 147715352110524
Author(s):  
DT Vu ◽  
H Vu ◽  
S Shin ◽  
NM Kieu ◽  
TQ Tien ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Light Emitting Diode ◽  
Optical Path Length ◽  
Light Emitting ◽  
Simple Strategy ◽  
Area Of Interest ◽  
Lenslet Array ◽  
Freeform Optics ◽  
Receiver Plane ◽  
Indoor Lighting

We introduce a compact lenslet array principle that takes advantage of freeform optics to deploy a light distributor, beneficial for highly efficient, inexpensive, low energy consumption light-emitting diode (LED) lighting system. We outline here a simple strategy for designing the freeform lens that makes use of an array of the identical plano-convex lenslet. The light is redistributed from such lenslet, hinging on the principle of optical path length conservation, and then delivered to the receiver plane. The superimposing of such illumination area from every lenslet occurs on the receiver plane, in which the non-uniform illumination area located in the boundary should have the same dimension as the size of the freeform lenslet array. Such an area, insofar, is negligible due to their small size, which is the crux of our design, representing a large departure from the former implementations. Based on simulations that assess light performance, the proposed design exhibited the compatibility for multiple radiation geometries and off-axis lighting without concern for the initial radiation pattern of the source. As simulated, the LED light source integrated with such proposed freeform lenslet array revealed high luminous efficiency and uniformity within the illumination area of interest were above 70% and 85%, respectively. Such novel design was then experimentally demonstrated to possess a uniformity of 75% at hand, which was close to the simulation results. Also, proposed indoor lighting was implemented in comparison with the commercial LED downlight and LED panel, whereby the energy consumption, number of luminaires and illumination performance were assessed to show the advantage of our simplified model.

scholarly journals Study of Plant Cultivation Using a Light-Emitting Diode Illumination System to Control the Spectral Irradiance Distribution

2017 ◽  
Vol 07 (06) ◽  
pp. 101-108
Author(s):  
Atsushi Motogaito ◽  
Naoki Hashimoto ◽  
Kazumasa Hiramatsu ◽  
Katsusuke Murakami
Keyword(s):  
Light Emitting Diode ◽  
Spectral Irradiance ◽  
Light Emitting ◽  
Plant Cultivation ◽  
Illumination System

Indoor Lighting Workplaces

2021 ◽  
pp. 243-258
Author(s):  
David Baeza Moyano ◽  
Roberto Alonso González Lezcano
Keyword(s):  
Power Distribution ◽  
Spectral Power ◽  
Light Emitting Diode ◽  
Working Environment ◽  
Office Work ◽  
Light Emitting ◽  
Spectral Power Distribution ◽  
Indoor Lighting ◽  
New Criteria

Office work has so far been carried out in company buildings and was largely based on the use of paper on a horizontal surface. Due to multiple reasons, more workers are working in their homes with electronic devices. As a result, both the working environment and personal tools are changing. Since the discovery about 20 years ago of the non-visual ways of light absorption, it was known that apart from the image forming effects (IF) of light from which the criteria for correct lighting have been developed, non-image forming effects (NIF) of light exist. The discovery of NIF has enhanced researcher belief in the importance of daylighting and has raised new criteria to be taken into account for proper interior lighting. Due to all the factors mentioned above, the parameters to be met by a luminaire and its environment for proper lighting of the workstation have been modified and expanded. The rapid advance in the development of new light-emitting diode (LED) luminaires with which the spectral power distribution (SPD) can be practically created opens the door to a genuine technological revolution comparable to the invention of electric lighting around 150 years ago. The authors of this study will review the latest published studies on the importance of light in our lives, IF and NIF effects of light, the parameters which from these effects are suggested to be taken into account for a correct indoor lighting, the regulations in force on indoor lighting workplaces, and proposals to improve indoor lighting and therefore the quality of life of workers.

Hybrid daylight/light-emitting diode illumination system for indoor lighting

2014 ◽  
Vol 53 (9) ◽  
pp. 1869 ◽  
Author(s):  
Aiming Ge ◽  
Peng Qiu ◽  
Jinlin Cai ◽  
Wei Wang ◽  
Junwei Wang
Keyword(s):  
Light Emitting Diode ◽  
Light Emitting ◽  
Illumination System ◽  
Indoor Lighting

scholarly journals Benzene and NOx photocatalytic assisted removal using indoor lighting conditions

2021 ◽  
Author(s):  
David Maria Tobaldi ◽  
Dana Dvoranová ◽  
Luc Lajaunie ◽  
Kristina Czikhardtová ◽  
Bruno Figueiredo ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Light Emitting Diode ◽  
Human Beings ◽  
Negative Consequences ◽  
Light Emitting ◽  
Lighting Conditions ◽  
Indoor Lighting

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.

scholarly journals Design and Implementation of a radio controlled led lighting system

2016 ◽  
Vol 10 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Ádám Bálint ◽  
József Sárosi
Keyword(s):  
Radio Frequency ◽  
Light Emitting Diode ◽  
Lighting System ◽  
Light Emitting ◽  
Led Lighting ◽  
Led Light ◽  
Design And Implementation ◽  
Technological Advances ◽  
History Of ◽  
Indoor Lighting

Technological advances allow us to control LED (Light Emitting Diode) lighting at home, in the office it can even allow us to change the intensity of the light and this is just the beginning of what the future holds for us. In this study an LED internal lighting fixture of our own design will be presented focusing on each step in its design. Firstly, the features, types and history of LEDs will be presented, next the products available in market that are required for the completion of the device. Finally, the design and implementation as well as the radio frequency controlled LED indoor lighting fixture will be shown.

White LED spectrum for minimising damage to Chinese traditional heavy colour paintings

2017 ◽  
Vol 50 (6) ◽  
pp. 911-920 ◽  
Author(s):  
R Dang ◽  
Y Yuan ◽  
G Liu ◽  
C Luo ◽  
J Liu
Keyword(s):  
White Light ◽  
Light Emitting Diode ◽  
Spectral Irradiance ◽  
Influence Coefficient ◽  
Light Sources ◽  
Inorganic Pigment ◽  
Light Emitting ◽  
Damage Level ◽  
Cielab Colour ◽  
Quantitative Influence

Optical radiation can cause permanent damage to the colours of high-responsivity Chinese traditional paintings. The white light emitting diode is flexible, efficient and can create similar colour phenomena with different spectra, making it easy to adjust the spectral irradiance distribution according to specific requirements. It is important to establish quantitative influence rules of white light emitting diode narrowband light for protecting traditional paintings, which optimises the constitution and proportion of the white light emitting diode spectrum according to the lowest damage level. In this study, we utilised typical narrowband spectra as light sources to illuminate Chinese traditional heavy colour paintings, and measured the CIELAB colour data periodically. We then calculated the colour difference based on the data and drew corresponding decay curves for the different pigments used. By analysing the quantitative influence characteristics, we were able to determine the quantitative influence and relative influence coefficient of each narrowband light type. These results provide a reference for the spectral irradiance distribution of the minimum-damage white light emitting diode for different heavy colour painting types based on the inorganic pigment characteristics.

scholarly journals Tuning the white light spectrum of light emitting diode lamps to reduce attraction of nocturnal arthropods

2015 ◽  
Vol 370 (1667) ◽  
pp. 20140125 ◽  
Author(s):  
Travis Longcore ◽  
Hannah L. Aldern ◽  
John F. Eggers ◽  
Steve Flores ◽  
Lesly Franco ◽  
...  
Keyword(s):  
Los Angeles ◽  
White Light ◽  
Light Emitting Diode ◽  
Spectral Composition ◽  
Unintended Consequences ◽  
Light Spectrum ◽  
Ecological Processes ◽  
Light Emitting ◽  
Study Sites ◽  
Indoor Lighting

Artificial lighting allows humans to be active at night, but has many unintended consequences, including interference with ecological processes, disruption of circadian rhythms and increased exposure to insect vectors of diseases. Although ultraviolet and blue light are usually most attractive to arthropods, degree of attraction varies among orders. With a focus on future indoor lighting applications, we manipulated the spectrum of white lamps to investigate the influence of spectral composition on number of arthropods attracted. We compared numbers of arthropods captured at three customizable light-emitting diode (LED) lamps (3510, 2704 and 2728 K), two commercial LED lamps (2700 K), two commercial compact fluorescent lamps (CFLs; 2700 K) and a control. We configured the three custom LEDs to minimize invertebrate attraction based on published attraction curves for honeybees and moths. Lamps were placed with pan traps at an urban and two rural study sites in Los Angeles, California. For all invertebrate orders combined, our custom LED configurations were less attractive than the commercial LED lamps or CFLs of similar colour temperatures. Thus, adjusting spectral composition of white light to minimize attracting nocturnal arthropods is feasible; not all lights with the same colour temperature are equally attractive to arthropods.

scholarly journals Design and compliant estimate of robot gripper with light-emitting diode and photodiode positioning

2019 ◽  
Vol 52 (9-10) ◽  
pp. 1319-1328 ◽  
Author(s):  
Anan Suebsomran
Keyword(s):  
Real Time ◽  
Force Feedback ◽  
Light Emitting Diode ◽  
Least Square ◽  
Feedback Signal ◽  
Time Estimate ◽  
Recursive Least Square ◽  
Light Emitting ◽  
Robot Gripper ◽  
Soft Objects

Generally, robot gripper is the tool to enhancing the efficiency and ability of grasping task of robot manipulator. The interaction between the object and the grasping finger is the main target of robotic gripper design stage. For this research, robot gripper is then proposed as the new method of robot gripper force control using real-time estimate force feedback signal in order to achieve higher performance of grasping objects. Robot gripper kinematics is also analyzed and adjusted to more practical development. The object manipulation is also identifiable using recursive least square estimation technique of both hard and soft objects during grasping. Force controller of robot gripper is obtained using real-time estimate force feedback signal by the recursive least square method. Comparison of proportional–integral–derivative controller gains is tuned with different force feedback signals, normal force feedback, and estimate force feedback during grasping hard and soft objects validated by experiment. The results of design and development are illustrated by simulation and experimental methods. In addition, due to the limitation of electromagnetic interference, signals will not affect other instrumentations with restricted working condition. The range of gripper motion is detected by applied visible light signal of light-emitting diode and photodiode as limit sensors.

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