6 resultados para Truth Recovery
em Greenwich Academic Literature Archive - UK
Resumo:
The recovery of platinum group metals (PGMs) from catalytic converters of spent exhaust systems is considered in this paper. To be cost-effective, recovery processes must be well over 90% efficient and so the optimisation of their operation is vital. Effective optimisation requires a sound understanding of the operation and the underlying process mechanisms. This paper focuses on pyrometallurgical recovery operations used and typified by the Johnson–Matthey process. Analysis of this process reveals that it cannot be simply explained by the gravity model that is normally assumed. The analysis reveals that the affinity of PGM particles for the melted collector metal is a key factor in the behaviour of the process. A rational explanation of the key issues that govern the process behaviour is proposed and shown to be consistent with available operational data. The results generated would be applicable to other similar processes.
Resumo:
A commercial pyrometallurgical process for the extraction of platinum-group metals (PGM) from a feedstock slag was analysed with the use of a model based on computational fluid dynamics. The results of the modelling indicate that recovery depends on the behaviour of the collector phase. A possible method is proposed for estimation of the rate at which PGM particles in slag are absorbed into an iron collector droplet that falls through it. Nanoscale modelling techniques (for particle migration or capture) are combined with a diffusion-controlled mass-transfer model to determine the iron collector droplet size needed for >95% PGM recovery in a typical process bath (70 mm deep) in a realistic time-scale (<1 h). The results show that an iron droplet having a diameter in the range 0.1–0.3 mm gives good recovery (>90%) within a reasonable time. This finding is compatible with published experimental data. Pyrometallurgical processes similar to that investigated should be applicable to other types of waste that contain low levels of potentially valuable metals.
Resumo:
Identification, when sought, is not necessarily obtained. Operational guidance that is normatively acceptable may be necessary for such cases. We proceed to formalize and illustrate modes of exchanges of individual identity, and provide procedures of recovery strategies in specific prescriptions from an ancient body of law for such situations when, for given types of purposes, individuals of some relevant kind had become intermixed and were undistinguishable. Rules were devised, in a variety of domains, for coping with situations that occur if and when the goal of identification was frustrated. We propose or discuss mathematical representations of such recovery procedures.
Resumo:
This Second Wave presentation focused on 'Creative Leadership and Communities of Practice', with particular reference to issues of trust affecting young people, unemployment and wider uncertainties in an economic recession when people were facing job cuts and in a social environment characterised by cynicism and a downturn in trust. Young people who join Second Wave are brought into a community of practice (CoP) (Lave and Wenger, 1991; Wenger, 1999) involving a dynamic, fluid process which is distinctive in its transformative power to change people's lives. The philosophy behind this involves Dewey's notion of the 'active self' (Dewey, 1916) and the theories of 'social constructivism' (Vygotsky, 1978). The process fosters trust, confidence and social learning (Bandura, 1977; Vygotsky, 1978) in which young people join in with a dialogue involving participation in the youth-centred creative space. The 'border zone' (Heath, 1994) in that creative space enables young people to connect with each other in the specialist field of youth arts. The youth-centred partnerships involved lead to greater confidence and development in a range of important artistic, social, cognitive and emotional skills and opportunities. Ultimately, the young person may become engaged in multi-agency working with Second Wave's external partners. Throughout all of these processes, young people are encouraged progressively to develop a more 'active self' to engage proactively with many different beneficial opportunities relating to the performing arts. In an era in which there has been a loss of trust in public life this is particularly important. If trust is defined in part as a belief in the honesty, competence and benevolence of others, it tends to act like 'social glue', cushioning difficult situations and enabling actions to take place easily that otherwise would not be permissible. The Edelman Trust Barometer for 2009 has recorded a marked diminution of trust in corporations, businesses and government, as a result of the credit crunch. While the US and parts of Europe were showing recovery from a generalised loss of trust by mid-year 2009, the UK had not. Social attitudes in Britain may be hardening - from being a nation of sceptics we may be becoming a nation of cynics: for example, only 13% of the population surveyed by Edelman trust politicians to tell the truth. In this situation, there is a need to promote positive measures to build trust. The presentation aims described key aspects of Second Wave's approach to identify and disseminate its model of good practice to make this more explicit and accessible to others. It is with awareness of the profoundly challenging circumstances facing young people, particularly but not exclusively in inner city urban areas such as Deptford, and the valuable contribution youth arts work can make to their well-being and development, that the presentation was carried out. In an era of generalised mistrust, the work done at Second Wave is crucial in empowering and supporting young people to find a positive and creative direction as part of the community.
Resumo:
Two media were developed which specifically allow the cultivation of Bacillus thuringiensis while it is in the vegetative as opposed to the spore form. Using these media B. thuringiensis was shown conclusively for the first time to exist in an active form on the phylloplane. The profile of its appearance in vegetative and spore form was followed over a growing season on clover (Trifolium hybridum) in the field. Three simultaneous and sudden rises and declines of both spore and vegetative cell densities were observed. The most common other spore-former on these leaves was Bacillus cereus but the fluctuations in appearance of these two very closely related species were not co-incident. Using specific PCR primers a considerable diversity of cry toxin gene types was found in isolates that had been recovered in vegetative form ([`]vegetative isolates') with the majority possessing multiple [delta]-endotoxin genes while some had only one of those tested. Bioassays against a lepidopteran insect of purified [delta]-endotoxins showed that they were no more potent than those from a laboratory-adapted strain. PCR primers for an internal region of the vip3A gene produced amplification in 70% of the vegetative isolates compared to 25% of the laboratory-adapted strains tested.