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The recently reported processing strategy called solvent-targeted recovery and precipitation (STRAP) enables deconstruction of multilayer plastic packaging films into their constituent resins by selective dissolution. It uses a series of solvent washes that are guided by thermodynamic calculations of polymer solubility. In this work, the use of antisolvents in the STRAP process was reduced and solvent mixtures were considered to enable the temperature-controlled dissolution and precipitation of the target polymers in multilayer films. This was considered as a means to further improve the STRAP process and its estimated costs. Two STRAP approaches were compared based on different polymer precipitation techniques: precipitation by the addition of an antisolvent (STRAP-A) and precipitation by decreasing the solvent temperature (STRAP-B). Both approaches were able to separate the constituent polymers in a post-industrial film composed primarily of polyethylene (PE), ethylene vinyl alcohol (EVOH), and polyethylene terephthalate (PET) with near 100 % material efficiency. Technoeconomic analysis indicates that the minimum selling price (MSP) of the recycled resins with STRAP-B is 21.0 % lower than that achieved with STRAP-A. This provides evidence that thermally driven polymer precipitation is an option to reduce the use of antisolvents, making the STRAP process more economically and environmentally attractive. A third process, STRAP-C, was demonstrated with another post-industrial multilayer film of a different composition. The results demonstrate that this process can also recover polymers at similar costs to those of virgin resins, indicating that the STRAP technology is flexible and can remain economically competitive as the plastic feed complexity is increased.

Previous work has shown that major changes to the thermohaline structure of the North Atlantic occurred between the pentads 1955–1959 and 1970–1974 and that these changes led to significant changes in the transport of the Gulf Stream system. Here we expand on these results by examining the changes in North Atlantic transports for the entire period 1950–1994. Based on temperature and salinity data from the Lozier climatology, and the deviations from this during different periods since 1950, the thermohaline densities are reconstructed. The circulations associated with these different periods are then derived using a diagnostic finite element model. The results show significant decadal variability in transports in both the sub-tropical and sub-polar gyres.

This study examines fertility decline that is larger than expected on the basis of recorded increases in contraceptive prevalence in Ghana. The primary sources of data are three Demographic and Health Surveys (DHS) conducted in the country in 1988, 1993 and 1998. First, the trend in fertility and contraceptive prevalence in Ghana is considered and compared with the trend that would be expected on the basis of prior research. Next, an attempt is made to uncover the explanation behind this unexpected trend. Measures of the quality of the survey data are looked at, as well as trends in the proximate determinants of fertility: contraceptive use, marriage and sexual activity, postpartum insusceptibility and induced abortion. Finally, evidence is presented that couples adjust their coital frequency in accordance with their fertility preferences, behaviour that would influence fertility rates but would not be captured by conventional measures of the proximate determinants of fertility.

This study was carried out for two reasons: to describe the major nongovernmental (NGO) community based distribution (CBD) programs in the country and to assess in some detail the functioning quality of care and performance of the Planned Parenthood Association of Ghana (PPAG) program. The results are to be used to strengthen future development of the NGO programs to inform the Ministry of Health on the role of these CBD models within the overall Primary Healthcare program and to guide partner organizations notably USAID in working with PPAGs and other CBD programs. (excerpt)