The universality of the application of PGC methods has long been a matter of dispute. Without doubt, most disagreement has come from those who have failed both to appreciate and then to observe the basic precepts outlined in this article.

Historically, the method found the greatest initial value in the identification of synthetic macromole-cules, while subsequent work by Shin Tsuge in Nagoya led to the elucidation of polymeric microstructures.

There followed studies explaining mechanical strength, cold-drawing properties, film-forming capabilities, cohesion within films and their adhesion to a wide variety of substrates, pigment binding, and the mechanisms of cross-linking processes.

Reiner was the first to appreciate that the difference between a synthetic macromolecule and a biopolymer was merely that of environment. In consequence his work on microbacter and cellular transformations must now be considered to be the foundation for much of today's clinical and pathological practice.

The FOM Foundation group in Amsterdam, under the stewardship of Meuzelaar, expanded the field of application of PGC in parallel with their pioneering work in pyrolysis/mass spectrometry. There, their initial focus was on a broad spectrum of natural polymers.

Wheals, of the British Metropolitan Police Forensic Laboratory, introduced PGC in criminology and developed techniques that formed a basis for standard practice in forensic laboratories. Results are now generally accepted as evidence in many criminal jurisdictions.

The virtue of the very small samples needed for the vast majority of diagnoses has seen adoption of PGC, conducted under very carefully controlled conditions, for the preservation of many art gallery and museum exhibits. For example, deteriorating ancient varnishes and pigments have yielded their secrets and pictures may be cleaned and/or restored without further damage, which will benefit the generations still to come.

Environmental and ecological applications are now coming to the fore. The analysis of occlusions of harmful volatile organics on air-borne particulates has contributed much to our understanding of their significance in the context of respiratory problems.

Bracewell was among the first to develop PGC for the assessment of soil fertility. More recently, De Leeuw graphically demonstrated that reasonably volatile organics such as polycyclic and halogenated hydrocarbons could be excised from very complex matrices (e.g. soils or sediments) by flash evaporation by imposing a millisecond thermal ramp on the sample.

Jones and Vanderborgh employed PGC in conjunction with other pyrolytic studies in their elucidation

I. W. Davies, Cambridge, UK Copyright © 2000 Academic Press

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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