Nature offers a range of colour displays which are relatively short‐lived and which were for many centuries little understood. Today we can explain most which arise from diffraction and reflection effects on rays of sunlight, various atmospheric ionisation phenomena and many colour effects resulting from biochemical reactions, although less is understood about some of the strange psychedelic patterns and colours which our brains can sometimes produce. The practical purposes to which certain fluorescent, thermochromic and photochromic dyes can be put, including their presently limited textile applications, are illustrated.
A few nanoparticle dispersions have been produced for centuries, but it is mainly during the past decade that they have been extensively developed for an amazing range of end uses, some in textile dyeing and finishing but more particularly in a technology now referred to as photonics. The developments in this field are reviewed with particular reference to improved, energy‐saving illuminants, computer and television displays, solar panels and digital communications. Fluorescent nanoparticles, which are now widely employed for sophisticated biomedical diagnostic testing (and possibly in future for treating the diseases themselves), are also described. Many nanoproducts are of almost molecular size and potentially very reactive, which has raised fears about possible, as yet unknown, environmental hazards. This review summarises the results of certain individual toxicity trials and the extensive joint programmes planned in both Europe and America.
To conserve or restore painted artwork, it is necessary to appreciate the nature of the basic materials used in its creation, to be able to identify the pigments and the application media that were originally – or have subsequently been – applied and to understand the nature of gradual chemical and physical degradation that occurs within the various components of the system. With information thus gained, one can determine how best a painting may be cleaned, restored and ultimately be better preserved. This review covers the range of analytical techniques (mostly spectrographic), which have often been specifically developed to aid the identification of the wide range of inorganic colours and organic binders (or their degradation products) that may be present in each paint layer of an old masterpiece. Although an art gallery or museum strives to conserve the artefacts it displays, over time there will be varying degrees of mechanical or chemical damage. Cleaning (and, more controversially, restoration work) therefore becomes necessary and the much‐improved methods now available for achieving this without associated adverse effects are reviewed.
This review presents a brief history of the development of light sources over the centuries to provide one of the human race's basic needs -light. Recent moves in Europe to encourage the adoption of compact fluorescent lamps as more energy-efficient replacements for incandescent lights, despite certain drawbacks, are described. Rapid strides are now being made in the development of solid-state 'white' lights which are already sufficiently durable and efficient to warrant adoption for both domestic and public lighting purposes. Their basic construction and comparative performance, properties and uses are fully described, together with the many ideas for improving their brightness and durability still further. Solid-state devices offer additional savings compared with those which should be achieved under the EU's targeted replacement of incandescent lights by 2012, and later one can expect such devices to compete with high-pressure sodium luminaires for street lighting.
More than any other factor, the rate and degree of diffusion of dves into the individual fibres composing any textile substrate control the productivity, reproducibility and the quality (with respect to appearance and sometimes the fastness properties) attained in each process. Using direct (fibre cross-section) measurement of the degree of penetration of dyes into nylon, polyester and acrylic fibres, under a variety o f application conditions, the relationships between dye penetration and visual colour yield has been determined with fibres differing in cross-sectional shape and delustrant content.The present interest in saving energy, time and water has led to numerous processes resulting in 'ring-dyeing: Batchwise dyeing for relatively short times or at somewhat abnormal temperatures, and continuous dyeing by rapid steam-fixation techniques are examples which have been investigated to define application conditions that might be expected to cause problems in bulk-scale production. Multi-layer Diffusion MethodAnother simple method for determining comparative rates of dye diffusion into any polymer which is available as a clear thin fiim, is the BASF Kombitest [ l ] , which has now been
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