Technical Report: The Mathematics of Orbital Solar Reflectors
Technical Report: The Mathematics of Orbital Solar Reflectors I. Executive Summary At the time of their original submission to the FCC for launch approval, Reflect Orbital claimed they would be able to deliver illuminances up to 5x that of a full moon (1.6 lux). A...
Visible Light Disinfection
In summary, visible light disinfection technology may be useful in some applications, but it is by no means a panacea. When designing or specifying a disinfection system, both the lighting designer and the client will need to thoroughly understand the capabilities and limitations of the technology, and agree upon its purpose.
Quantifying Light Pollution Sources
time light pollution is sadly familiar to all of us. While our grandparents and great-grandparents may talk fondly of seeing the Milky Way in their youth, with thousands of stars scattered across the dark summer sky, we are mostly content with seeing a few dozen stars through the never-ending dusk of urban and suburban skies.
Defining Far-Ultraviolet
In these uncertain times, there is increasingly persuasive evidence that “far-UV” radiation is effective in inactivating the SARS-CoV-2 virus and other pathogens, but without the health risks of germicidal ultraviolet radiation. Unfortunately, this technology has...
Visual Glare and CIE 117-1995 – NEMA White Paper
The CIE Unified Glare Rating (UGR) metric has been use by the architectural lighting industry since it was first published by the CIE a quarter-century ago (CIE 117-1995, Discomfort Glare in Interior Lighting). Originally popularized by European lighting...
Horticultural Lighting Design and Déjà Vu
The phrase déjà vu translates from French as “already seen,” which nicely describes a current issue with horticultural lighting design. The introduction of LED technology may have kick-started horticultural lighting as an innovative industry, but we have yet to...
The Effect of Near-Infrared Radiation on Plants
Look at any textbook on botany and you will find this maxim: plants respond to optical radiation in the spectral range of 280 nm to 800 nm. Period, end of discussion. The question is, how was this spectral range (sometimes referred to as Photobiologically Active...
Specifying LED Colors for Horticultural Lighting
This paper proposes an LED “color” specification that represents a given SPD using a small number of radial basis functions, to provide a metric for comparing biologically similar SPDs. It further introduces a trainable fuzzy logic SPD classifier that can compare biologically similar SPDs for specific horticultural applications.
Ultraviolet Radiation & Viral Misinformation
Let me begin with a smorgasbord of headlines: 99.9% of Covid-19 virus dead in 30 seconds with UV LEDs, says Tel Aviv research (www.malaysianow.com) UV-emitting LED lights found to kill coronavirus (www.sciencedaily.com) Study reveals UV LED lights effectively kill...
Ultraviolet Radiation Terminology
A word of caution: I am going to be annoyingly pedantic here, but with good reason. The lighting industry has a century-long history of introducing unfamiliar technologies using familiar terminology. We later come to regret our choice of words when it becomes...