Change in maternal perception of sibling negativity: within- and between-family influences.

Change in maternal report of sibling negativity was investigated in 313 sibling dyads from 171 families taking part in a longitudinal, general population survey in the United Kingdom. The inclusion of multiple dyads per family allowed for the emergence of 3 novel elements for sibling research: an examination of within-family similarity on sibling relationship quality, modeling within-family similarity as a function of the shared environment and the differentiation of family-wide and dyad-specific predictors. Moderate similarity on sibling negativity was found across different sibling dyads and similarity was higher in 2 versus lone-parent families. Maternal negativity, genetic relatedness, age of the oldest child in the dyad, and the interaction between lone-parent status and maternal differential treatment were found to predict change in sibling negativity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Theory of fire and fire processes

There are two major fire processes, an understanding of which is essential for effective fire safety design: (1) the conditions under which a combustible material may become involved in flaming combustion, and (2) the rate at which such a material, once involved, will provide an output of heat, smoke, toxic gases, etc., which can endanger people and property. The first process may be regarded as covering both ignition and spread of fire on materials; its complement is the way in which fire may become extinguished. It is necessary for such processes to bring in a characteristic of the basic combustion reaction which, directly or indirectly, expresses the reactivity of the combustion process. Thus pilot ignition is usually associated with an approximate surface fuel temperature. More basically, it is associated with a critical flow rate of volatiles and a critical heat loss from the flame, the latter being influenced by ambient oxygen and temperatures conditions as well as heat lost and gained by the fuel itself. The most important factor governing the production of dangerous product is the rate at which volatiles first (fuel controlled fires) and later air (air controlled fires) are fed into the flames. The reactivity is of less importance, although it may be one of the factors which control combustion efficiency. In general, the more efficient is the combustion the more heat is produced, but the less smoke and toxic gases are produced. Some of the main advances in the above areas are reviewed in this paper.     

Developments in Structured-Wall Plastics Sewer Pipes and a Method of Testing Their Resistance to Damage

Structured-wall plastics sewer pipes rely upon the structural configuration of their walls to enhance their stiffness, whilst saving on material. Their properties and performance vary widely with the type and material from which they are made, and opinion is divided as to the acceptability of these products for sewerage systems. The UK water industry and the Committee for European Normalisation are actively developing standards for them, but there are a number of performance-related concerns which need to be addressed if they are to be accepted in the UK.
A test, which measures a pipe's resistance to being damaged, has been developed at the University of East London, and preliminary results confirm a wide variation in performance.     

Review of explosion and fire hazard of liquefied petroleum gas

The properties of LPG that contribute to its fire and explosion hazards are outlined. The hazards include those associated with small vapour leaks from appliances and gas cylinders as well as major hazards associated with loss of containment and rapid vaporisation of tonnage quantities of the liquefied gas. Estimates are given of the magnitude of effects that might follow the latter type of release. In the UK the record of LPG is poor with regard to general fire occurrence compared with that of natural gas or town gas. This performance will need to be improved if the quantity of LPG used is to be increased. These improvements might be achieved by developing its use as a piped fuel and in motor vehicles, but both these would require careful hazard analysis. Although the record for major hazard with LPG in the UK is good, quantitative studies indicate that handling and transportation of tonnage quantities by road and sea are not safe enough. Methods are suggested for reducting the risk.