China
Africa
Explore chapters and articles related to this topic
Introduction
Published in J. R. Coaton, A. M. Marsden, Lamps and Lighting, 2012
These general ideas apply for any type of metal halide discharge. To achieve a high efficacy white light source with good colour rendering, the metal halide lamp designer has many variables to play with, including the number of types of metal halides added and their relative concentrations. This design freedom comes with a penalty: metal halides react slowly with the lamp electrodes and walls. Therefore, life, colour stability, colour variability, colour separation within the arc, maintenance, starting and visible flicker are all affected by these reactions. This is the reason why, 35 years after their invention in 1959, metal halide lamps have still not displaced all other high-intensity light sources. Despite this metal halide lamps provide great benefits in the right applications. The metal halide lamps successfully sold today are the result of tremendous development over the past 30 years (see, for example, Waymouth 1971, Keeffe 1980 and Suguira 1993).
How to Design a Lighting System
Published in Scott C. Dunning, Albert Thumann, Efficient Lighting Applications and Case Studies, 2020
Scott C. Dunning, Albert Thumann
The metal halide (MH) lamp is very similar in construction to the mercury vapor lamp. The major difference is that the metal halide lamp contains various metal halide additives in addition to the mercury vapor. The efficacy of metal halide lamps is from 1.5 to 2 times that of mercury vapor lamps. The metal halide lamp produces a relatively “white” light, equal or superior to presently available mercury vapor lamps. The main disadvantage of the metal halide lamp is its relatively short life (7,500 to 20,000 hours).
Lighting Systems
Published in Stephen W. Fardo, Dale R. Patrick, Electrical Power Systems Technology, 2020
Stephen W. Fardo, Dale R. Patrick
Another type of vapor lamp is called a metal halide type. This light source is a high intensity mercury-vapor lamp in which metallic substances, called metal halides, are added to the bulb. The addition of these substances improves the efficacy of the lamps. The efficacy of a metal halide lamp is typically 75 lumens/watt, compared to approximately 50 lumens/watt for mercury-vapor lamps.
Utilization of activated carbon for maximizing the efficiency of zirconium oxide for photodegradation of 4-octylphenol
Published in Journal of Environmental Science and Health, Part A, 2019
Mohamed E. M. Ali, Tarek S. Jamil, Ahmed Abdel-Karim, Ahmed A. El-Kady
In order to study the photocatalytic degradation of 4-OP, aslurry-mode batch reactor is used. All experiments were performed under agitated conditions using magnetic stirring. The source of visible light was a commercial visible metal halide lamp (HQI-T 250/Daylight, OSRAM GmbH, Germany) with luminous flux of irradiation 20,000 lm and 82 lm W–1 luminous efficacy. The entire setup was placed into a reflective housing to prevent external light from entering the system and to keep the light generated by the lamp within the setup.Samples (∼ 5 mL, filtered using PTFE membrane 0.22 µm) periodically drawn from the reactor vessel were analyzed by means of Agilent 1100 high performance liquid chromatography (HPLC) to follow concentration profiles of the original organic substrate and, its primary degradation product. The samples were analyzed using UV detector coupled with ODS C18 column, Zorbax reversed C18 (4.6 mm I.D. × 250 mm, particle size 5 µm). The mobile phase used was acetonitrile/water (50/50) with isocratic flow rate of 1 mL min−1. Prior to photodegradation experiment, the solution was stirred for 30 min in dark to allow adsorption equilibrium.