Exclusion and Marginalisation in Adolescence: The Experience of School Exclusion on Drug Use and Antisocial Behaviour

Young people excluded from school are a group at an increased risk to drug use and antisocial behaviour during adolescence and later marginalisation and exclusion from society in adulthood (Blyth and Milner, 1993). As part of the Belfast Youth Development Study, a longitudinal study of the onset and development of adolescent drug use, young people who entered post primary school in 2000 (aged 11/12 years) were surveyed annually on four occasions. This paper reports on findings from this survey in relation to a supplementary group of young people who were surveyed because they had been excluded from school. The findings show higher levels of drug use and antisocial behaviour among school excludees, lower levels of communication with their parents/guardians, higher levels of contact with the criminal justice system and increased likelihood of living in communities characterised with neighbourhood disorganisation. This lifestyle perhaps suggests these young people are leading a life that is already taking them towards the margins of society.

Periodic transonic flow and control

The current understanding of periodic transonic flow is reviewed briefly. The effects of boundary-layer transition, non-adiabatic wall conditions and modifications to the aerofoil surface geometry at the shock interactions on periodic transonic flow are discussed. Through the methods presented, it is proposed that the frequency of periodic motion can be predicted with reasonable accuracy, but there are limitations on the prediction of buffet boundaries associated with periodic transonic flows. Several methods have been proposed by which the periodic motion may be virtually eliminated, most relevantly by altering the position of transition fix, contouring the aerofoils surface or adding a porous surface and a cavity in the region of shock interaction. In addition, it has been shown that heat transfer can have a significant effect on buffet.

A geotechnical description of fresh cement grout - filtration and consolidation behaviour

The removal of water from three Portland cement grouts by pressure filtration is examined, and the consolidation behaviour of the filtered material clarified. The filtration takes place by the laying down of a very stiff filter cake through the removal of excess water. The behaviour due to further loading resembles that of a re-constituted silt. For stress levels above the filtration pressure the calculated permeability values are similar to those from the filtration phase only if the data sampling rate was sufficiently rapid to discriminate the first portion of the observed primary consolidation curve. The change in void ratio for incremental loading is roughly linear with the change in the logarithm of the vertical effective stress. The characterisation of fresh cement paste using standard soil mechanics models is both appropriate and useful, at least during the first few hours after mixing.