Lamps

Abstract

The article contains sections titled: 1. Introduction 2. Light Generation 2.1. Thermal Radiation from Solids 2.2. Radiation from Gas Discharges 2.3. Radiation from Semiconductors (LEDs) 2.4. Modeling of Lamps 3. Main Types of Lamps 4. Lamp Chemistry 4.1. General 4.2. Transport Chemistry 4.2.1. Principles 4.2.2. Incandescent Lamps 4.2.3. Halogen Incandescent Lamps 4.2.4. Metal Halide Lamps 5. Basic Lamp Materials 5.1. Metals 5.2. Glass 5.2.1. Glass Composition and Glass Types 5.2.2. Properties 5.2.3. Glasses for Lamp Types 5.2.4. Glass‐to‐Metal Seals 5.3. Polycrystalline Alumina 5.4. Fluorescent Powders 6. Special Lamp Materials 6.1. Getters 6.2. Amalgams 6.3. Emitters 6.4. Cements and Marking Paints 7. Coatings 8. Lamp Production 9. Economic Aspects and Uses

Solar Photochemical Synthesis: From the Beginnings of Organic Photochemistry to the Solar Manufacturing of Commodity Chemicals

“…In contrast to these advantages, photochemical processes are often unsustainable due to limitations of the available technology, especially on technical scales, , or unfavorable photophysics of the reaction. Some of the most common drawbacks include the following: Strong light sources are dangerous to humans and require strict operating protocols such as shielding . Likewise, light can rapidly damage reactor materials, thus demanding costly replacements. Conversion of electrical power into light comes with substantial heat generation, which requires energy- and water-intensive cooling. Optical filters are often necessary to remove destructive emission wavelengths, hence reducing energy efficiency of the light sources. Most artificial light sources have limited lifetimes and their renewal causes significant maintenance costs. Complete light absorption is typically achieved within a thin layer of the reaction medium (as expressed in the Beer–Lambert law), thus necessitating high dilutions and solvent needs. Photochemical reactions require inert and transparent solvents and are therefore frequently performed in hazardous benzene, acetonitrile, carbon tetrachloride, dichloromethane, or methanol. Typical batch processes suffer from subsequent degradation of photochemically unstable products, which lowers product qualities and yields. Most photochemical transformations suffer from low quantum efficiencies due to dominant photophysical deactivation pathways .…”

“…Strong light sources are dangerous to humans and require strict operating protocols such as shielding . Likewise, light can rapidly damage reactor materials, thus demanding costly replacements.…”