Numerical investigation of conjugated heat transfer in a channel with a moving depositing front

This article presents numerical simulations of conjugated heat transfer in a fouled channel with a moving depositing front. The depositing front separating the fluid and the deposit layer is captured using the level-set method. Fluid flow is modeled by the incompressible Navier–Stokes equations. Numerical solution is performed on a fixed mesh using the finite volume method. The effects of Reynolds number and thermal conductivity ratio between the deposit layer and the fluid on local Nusselt number as well as length-averaged Nusselt number are investigated. It is found that heat transfer performance, represented by the local and length-averaged Nusselt number reduces significantly in a fouled channel compared with that in a clean channel. Heat transfer performance decreases with the growth of the deposit layer. Increases in Reynolds, Prandtl numbers both enhance heat transfer. Besides, heat transfer is enhanced when the thermal conductivity ratio between the deposit layer and the fluid is lower than 20 but it decreases when the thermal conductivity ratio is larger than 2

The influence of fibre production history and stress on the durability of polypropylene

The authors have examined the effect of stress on the thermal-ageing behaviours of polypropylene tapes and filaments which have different degrees of orientation. Two polymer samples which contained stabilisers of different efficiencies were extruded into tapes and filaments and then subjected to draw ratios of 4 : 1 and 8 : 1. These products were oven-aged at temperatures in the range 90–130°C and simultaneously stressed at levels up to 15% of respective breaking loads. Effects of over-ageing were monitored by studying the tensile properties. For the more highly stabilised samples, little effect of either stress or draw ratio was noted. However, the less efficiently stabilised samples had durabilities which reduced with increasing initial draw ratio and applied stress. This latter observation identified important consequences for the long-term stability of polypropylene products used under load

Demonstration of the possible competing effects of oxidation and chain scission in orientated and stressed polypropylenes

A series of orientated polypropylene tapes and filaments with differing draw ratio were produced from two parent polymers containing antioxidant systems of different efficiencies. Lengths of tapes and filaments were exposed in air ovens at temperatures up to 130°C under “free” conditions, held at constant length or loaded to differing stress levels for prescribed times or to failure, whichever was earlier. Those morphological effects of oven ageing treatments as are identified from their subsequent tensile behaviors and densities have been reported elsewhere; this study reports the heat flux differential scanning calorimetric (HF‐DSC) observations of unexposed and exposed samples. The HF‐DSC curves of treated samples show, for the postfusion oxidative exotherm for oven‐exposed samples, positive shifts to lower values compared with an unexposed sample, of the extrapolated onset temperature (Ton). Analyses of the tensile, density, and HF‐DSC data suggest that during the initial stages of thermal degradation in air, chain scission competes with oxidation. The rates of the former are enhanced by the application of stress, and scission is considered the origin of the observed deterioration in tensile behavior. Concurrent oxidation during oven exposures affects subsequent autoxidative behavior but has little immediate influence upon the mechanical properties

It is possible for people diagnosed with schizophrenia to recover

Services that support individuals with a diagnosis of Serious Mental Illness are called upon to deliver services that seek to promote their recovery.The National Institute for Mental Health in England (NIMHE, 2005), have been working towards defining the key features of what a recovery oriented service should look like. Optimistic as it may seem, services are a long way to undoing the effects of institutionalisation in the lives of many service users. This article provides an account of an evaluation of a Recovery Group designed to introduce participants to the recovery paradigm, in an attempt to help enhance their hopefulness about their future. It was hypothesised that when people are hopeful about achieving their goals, then they will become more motivated to pursue meaningful activities. An eight week group was conducted using outcome measures such as the Beck Hopelessness scale (1974), Lancashire Quality of Life scale, Bradburn Affect Scale and Cantill’s Life Ladder. Seven mental health service users from a Rehabilitation Inpatient Unit, and Community Team participated in the Recovery group, of whom four service users completed the programme. Despite methodological limitations of this evaluation some improvements were noted for the service users in terms of improved quality of life, a sense of optimism for the future and improved psychological well-being