A Study of Stress Factors in Perthes' Disease of the Hip, Using the Finite Element Method

Use of expanding foam in roofs Eric Skilton, of John Pryke & Partners, writes expressing concern over the apparent growing use of expanding foam for the insulation and stabilisation of old roof coverings: While this process would appear to fulfil its intended function of upgrading the insulation to the loft space and providing additional fixity to the roof covering, it strikes me that we are sowing the seeds of future problems with this refurbishment technique. Verulam

Standard production steel reinforcement protected with a fusion-bonded epoxy coating has been subjected to accelerated testing on a natural exposure site over a 5-year period alongside plain steel and galvanised steel in purpose-designed concrete specimens. The epoxy coating provided considerable protection to the steel for the length of the trial when exposed in concrete with a high concentration of added chloride leading to significant practical advantage. However, the use of these coatings in practice does not provide complete protection since corrosion was observed to be spreading from points of defect in the coatings when the steel was embedded in concretes containing high levels of chloride. K.W.J. Treadaway and H. Davies

Corrosion of reinforcement in concrete has in recent years become more widespread and of greater concern than in the past. There are numerous causes, many avoidable, for the increase in corrosion, not least among these being the large volume of rapid construction in the 1960s and '70s. A.S. Safier