Structural Gallery

Lime tree stem, light micrograph

Lime tree stem. Light micrograph of a section through the stem of a lime tree (Tilia europaea). The outer epidermis has been shed and replaced by a layer of cork (dark red). Under the cork is the outer cortex layer of flexible collenchyma tissue (dark blue and red) and a lower cortex of parenchyma (blue). Next is a ring of phloem (blue) with large sieve tubes, companion cells and fibres (pink). The phloem is broken by primary medullary rays (blue, triangular) and thin subsidiary medullary rays (dark blue). Next is a ring of xylem (pink) with large files of vessels and small woody parenchyma (light blue). The primary xylem (dark blue) and the central pith of parenchyma tissue (light blue) are also shown. Magnification: x5 when printed 10 centimetres

© DR KEITH WHEELER/SCIENCE PHOTO LIBRARY

Chemical plant storage tanks

Chemical plant storage tanks. The industrial-scale manufacture of chemicals requires specialised engineering to meet a wide range of storage requirements. Products and reactants, ranging from liquids to gases and solids, have to be kept at the correct temperature and pressure. They then need to be piped or transported around the site to and from these storage facilities. These tanks are part of a larger oil refinery and chemical manufacturing site. Oil refining and chemical manufacturing are closely related industries, as oil products are used in a wide range of chemical industry manufacturing processes. Photographed at ExxonMobil's Fawley Oil Refinery and Chemical Plant, Hampshire, UK, which is one of the largest petrochemical plants in Europe

© PAUL RAPSON/SCIENCE PHOTO LIBRARY

Fullerene molecule, computer artwork

Fullerene molecule. Computer artwork of the spherical fullerene molecule C320. Fullerenes are a structural type (allotrope) of carbon. The molecular model here shows the spherical arrangement of the 320 carbon atoms in rings of hexagons and a few pentagons. The spherical fullerenes are sometimes referred to as buckyballs, after the first such molecule to be discovered (C60, buckminsterfullerene). As of 2006, research is being conducted into the use of fullerenes for medical purposes. Fullerenes are also being investigated for their physical and chemical properties

© LAGUNA DESIGN/SCIENCE PHOTO LIBRARY