Scaleup of wet granulation processes: science not art

Significant advances have been made in the last decade to quantify the process of wet granulation. The attributes of product granules from the granulation process are controlled by a combination of three groups of processes occurring in the granulator: (1) wetting and nucleation, (2) growth and consolidation and (3) breakage and attrition. For the first two of these processes, the key controlling dimensionless groups are defined and regime maps are presented and validated with data from tumbling and mixer granulators. Granulation is an example of particle design. For quantitative analysis, both careful characterisation of the feed formulation and knowledge of operating parameters are required. A key thesis of this paper is that the design, scaleup and operation of granulation processes can now be considered as quantitative engineering rather than a black art. Résumé

Representing part-whole relationships in conceptual modeling: An empirical evaluation

The part-of or part-whole construct is a fundamental element of many conceptual modeling grammars that is used to associate one thing (a component) with another thing (a composite). Substantive theoretical issues surrounding the part-whole construct remain to be resolved, however. For instance, contrary to widespread claims, the relationship between components and composites is not always transitive. Moreover, how the partwhole construct should be represented in a conceptual schema diagram remains a contentious issue. Some analysts argue composites should be represented as a relationship or association. Others argue they should be represented as an entity. In this paper we use an ontological theory to support our arguments that composites should be represented as entities and not relationships or associations. We also describe an experiment that we undertook to test whether representing composites as relationships or entities enables users to understand a domain better. Our results support our arguments that using entities to represent composites enables users to better understand a domain.

Abstract specification in Object-Z and CSP

A number of integrations of the state-based specification language Object-Z and the process algebra CSP have been proposed in recent years. In developing such integrations, a number of semantic decisions have to be made. In particular, what happens when an operation's precondition is not satisfied? Is the operation blocked, i.e., prevented from occurring, or can it occur with an undefined result? Also, are outputs from operations angelic, satisfying the environment's constraints on them, or are they demonic and not influenced by the environment at all? In this paper we discuss the differences between the models, and show that by adopting a blocking model of preconditions together with an angelic model of outputs one can specify systems at higher levels of abstraction.

The (new ?) basics of a teacher professional learning community

This paper argues for the need to further theorise the concept of teacher professional learning communities and provides empirical evidence to support this case. The paper presents findings from an ongoing research project, which investigates the nature of teacher professional learning communities. The study reveals that actual communities do not conform to a normailized articulation of features, as outlined in much of the literature on this topic. Consequently, it represents an attempt to engage in the difficult but necessary task of simultaneously fashioning theory from practice, whilst interpreting theory, in practice. The study proposes that current functionalist understandings of teacher professional learning communities are based upon a literature base which is insufficiently nuanced to capture the complexity inherent within these bodies. A broader base of a more critical sociological literature is also drawn upon to better understand actual, "lived" teacher communities, which are somewhat difficult to describe. In part, such communities exhibit features of functionalist conceptions but they are also organic entities which may be quite unpredictable in their outcomes and cannot be reduced to specific features; they each have their own specific "logic of practice" (Bourdieu, 1990) which influences their activities, in their particular field. The argument proposed here is that in one particular community, this complexity may be represented by the many purposes which the community served, arguably often unbeknown to its members, which fashioned the actual community. This paper tries to add to the existing theoretical base of literature, at the same time as providing evidence to support this theorisation.