Technical Report: Photobiological Hazard Assessment of Orbital Solar Reflectors
Executive Summary This report details a photobiological hazard assessment of the general concept of Orbital Solar Reflectors (OSRs). A recent proposal, Reflect Orbital’s proposed Earendil-1 satellite is used as an exemplar. The analysis was conducted following IEC...
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...
Spherical Irradiance and Aerosols
Lighting designers will be familiar with the illuminance of a planar surface, which is measured in lumens per square meter (or foot). The irradiance of a planar surface by a germicidal radiation source is conceptually the same, except that it is measured in watts...
Defining Photosynthetic Photon Efficacy
There has been some discussion online and in presentations recently about the issue of photosynthetic photon flux. The argument goes as follows: Photosynthetically Active Radiation (PAR) is somewhat arbitrarily defined as optical radiation within the spectral range...