Fluorescent device exposure

Figure 18.12 Effect of fluorescent device exposure on carboxylic acid production in Spectar copolymer as determined by SF4 treatment 1816cm-1, aromatic acid peak 1841 cm1, aliphatic acid peak [11]. Reprinted from Polymer, 41, Grossetete, T., Rivaton, A., Gardette, J.-L., Hoyle, C. E., Ziemer, M., Fagerburg, D. R. and Clauberg, H., Photochemical degradation of poly(ethylene terephtha-late)-modified copolymer, 3541-3554, Copyright (2000), with permission from Elsevier Science...

It appears, therefore, that two accelerated devices may be needed an exposure unit, such as the Fade-ometer, for quick screening and relative performance studies of light-stabilized polystyrene samples, and a second unit, such as the high output fluorescent lamp, for predicting more accurately long term exposures. 

In addition, a great need exists for improved test procedures to predict end-use performance. The correlations between accelerated exposure devices and normal fluorescent lamps, described in this report, represent only a preliminary effort to refine and establish meaningful laboratory methods for evaluating light stabilizers. Exposure data from a greater number of samples, containing a greater variety of formulations, are needed for more accurate correlations. 

A crude but inexpensive alternative to the mask aligner is to physically clamp the substrate to the mask, then use a UV light box, which contains several black-light fluorescent tubes, for the exposure process. With care, this procedure can produce features in the vicinity of 5 ixm and larger, making it possible to fabricate 150 MHz SAW devices on quartz, for example. 

Metallic mercury is used in a variety of household products and industrial items, including thermostats, fluorescent light bulbs, barometers, glass thermometers, and some blood pressure devices. The mercury in these devices is contained in glass or metal, and generally does not pose a risk unless the item is damaged or broken, and mercury vapors are released. Spills of metallic mercury from broken thermometers or damaged electrical switches in the home may result in exposure to mercury vapors in indoor air. You must be careful when you handle and dispose of all items in the home that contain metallic mercury. 

Although PCBs are no longer made in the United States, people can still be exposed to them. Many older transformers and capacitors may still contain PCBs, and this equipment can be used for 30 years or more. Old fluorescent lighting fixtures and old electrical devices and appliances, such as television sets and refrigerators, therefore may contain PCBs if they were made before PCB use was stopped. When these electric devices get hot during operation, small amounts of PCBs may get into the air and raise the level of PCBs in indoor air. Because devices that contain PCBs can leak with age, they could also be a source of skin exposure to PCBs. 

A Vivitar Model VP-1 xenon flash lamp with a preset exposure time of 1/500 s, and a desk lamp with two F15T8 black light fluorescent bulbs were used as exposure devices in two experiments. 

PAEs are chromic and reveal fascinating spectroscopic properties upon exposure to external stimuli. The UV-vis and fluorescence properties of selected PAEs are treated with regard to inter- and intrachain processes and a model for the spectral changes in PPEs is developed. In the last part, the uses of PAEs as fluorescent sensors and in semiconductor devices are discussed. 

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