A hybrid particle-number and particle model for efficient solution of population balance equations

This work presents a hybrid particle-number and particle model to improve efficiency in solving population balance equations for type spaces spanning spherical and aggregate particles. The particle-number model tracks simpler, spherical particles cheaply by storing only the number of particles with a given one-dimensional internal coordinate, while the particle model allows resolution of the detailed aggregate structure that occurs due to collision and coagulation between particles by storing distinct computational entries for each particle. This approach is exact if primary particles are defined by their monomer count and the particle-number model increments in single monomers. A stochastic method is used to solve the population balance equations for the combined type space. The hybrid method works well for large ensembles ($>2^{12}$ particles) with a detailed particle model, where performing a finite number of particle-number updates is demonstrated to be 40--50\% cheaper than updating an equivalent ensemble of discrete particles. These savings can be traded for a larger sample volume to increase the resolution in the particle size distribution or more repeat runs to reduce the total error. Run time improvements are curtailed at very high surface growth and coagulation rates due to the fixed cost of growth updates on the large aggregates formed; however, the hybrid method is still attractive in this case as its primary purpose is to reduce error by preventing saturation of the ensemble with simple particles at high inception rates.National Research Foundation, Prime Minister's Office, Singapore under its Campus for Research Excellence and Technological Enterprise programme. Venator

Study of industrial titania synthesis using a hybrid particle-number and detailed particle model

We apply a hybrid particle model to study synthesis of particulate titania under representative industrial conditions. The hybrid particle model employs a particle-number description for small particles, and resolves complicated particle morphology where required using a detailed particle model. This enables resolution of particle property distributions under fast process dynamics. Robustness is demonstrated in a network of reactors used to simulate the industrial process. The detailed particle model resolves properties of the particles that determine end product quality and post-processing efficiency, including primary particle size and degree of aggregate cohesion. Sensitivity of these properties to process design choices is quantified, showing that higher temperature injections produce more sintered particles; more frequent injections narrow the geometric standard deviation of primary particle diameter; and chlorine dilution reduces particle size and size variance. Structures of a typical industrial particle are compared visually with simulated particles, illustrating similar aggregate features with slightly larger primary particles

Towards a Butlerian methodology: undoing organizational performativity through anti-narrative research

This article explores the methodological possibilities that Butler’s theory of performativity opens up, attempting to ‘translate’ her theoretical ideas into research practice. Specifically, it considers how research on organizational subjectivity premised upon a performative ontology might be undertaken. It asks: What form might a Butler-inspired methodology take? What methodological opportunities might it afford for developing self-reflexive research? What political and ethical problems might it pose for organizational researchers, particularly in relation to the challenges associated with power asymmetries, and the risks attached to ‘fixing’ subjects within the research process? The article outlines and evaluates a method described as ‘anti-narrative’ interviewing, arguing that it constitutes a potentially valuable methodological resource for researchers interested in understanding how and why idealized organizational subjectivities are formed and sustained. It further advances the in-roads that Butler’s writing has made into organization studies, thinking through the methodological and ethical implications of her work for understanding the performative constitution of organizational subjectivities. The aim of the paper is to advocate a research practice premised upon a reflexive undoing of organizational subjectivities and the normative conditions upon which they depend. It concludes by emphasizing the potential benefits and wider implications of a methodologically reflexive undoing of organizational performativity

Detailed population balance modelling of TiO<2_{2} synthesis in an industrial reactor

This paper uses a network of ideal flow reactors and a detailed population balance model to study the evolution of the size and shape distributions of pigmentary titanium dioxide, formed under industrial synthesis conditions. The industrial reactor has multiple reactant injections, a tubular working zone in which the exothermic reaction is completed, and a cooling zone. A network of continuously stirred tank reactors is used to model variation in composition around the feeds and plug flow reactors with prescribed temperature gradients are used to describe the working and cooling zones. The quality of the industrial product depends on its morphology, and this is influenced by factors including temperature and throughput. In this paper, a multivariate particle model is accommodated using a stochastic method and the particle morphology is characterised in terms of the distributions of primary and aggregate particle diameters, number of primary particles per particle and neck radii of connected primary particles. Increasing temperature or residence time is shown to produce larger particles. Qualitative similarities are highlighted between such findings and previous studies. The throughput studies are also in qualitative agreement with empirical industrial experience. There is scope for extending and improving the current model; however, it is suggested that insights of this type could be used to inform the design and operation of the industrial process.This project is partly funded by the National Research Foundation (NRF), Prime Minister’s Office, Singapore under its Campus for Research Excellence and Technological Enterprise (CREATE) programme. The authors would like to thank Huntsman Pigments and Additives for financial support

Re-storying and visualizing the changing entrepreneurial identities of Bill Gates and Richard Branson.

The storytelling in textual and visual re-constructions of Bill Gates and Richard Branson by their organizations produces entrepreneurial identities bound into particular social power-knowledge relations. Our purpose is to examine how these organizations, and their critics, mobilize storytelling in acts of re-storying (enlivening) or re-narrating (branding a monologic) practices using Internet technologies to invite viewers to frame the world of entrepreneurship. We use visual discourse and storytelling methods to analyze how Microsoft and Virgin Group use various kinds of entrepreneurial images and textual narratives to re-narrate and produce particular brands of capitalism. These organizations' scoptic regimes of representation are contested in counter-visualizing and counterstory practices of external stakeholders. We suggest that the image and textual practices of storytelling have changed as both entrepreneurs court philanthropic and social entrepreneur identity markers. Our contribution to entrepreneurial identity is to apply double and multiple narrations, the appropriation of another's narrative words (or images) into another's narrative, and relate such storytelling moves to visuality

Paradoxes of creativity : examining the creative process through an antenarrative lens

Accounts of the creative process tend to be retrospective and implicitly ground the creative act within the person, the mind, the moment, the idea; in doing so, they often miss the larger sociomaterial qualities that can provide us with important insights about the social relationality and playfulness of the creative process. In this article, we examine the creative process through an antenarrative lens that we consider very useful for theorizing the creative process from a cultural and sociomaterial perspective. More specifically, we argue that ‘having an idea’ is a contextualized and embodied process that can be regarded as an antenarrative of the overall creative process. We also discuss how the paradoxical relation between the formative and sudden manifestations of the creative act can be understood through the notion of play

Reaching across continents : engaging students through virtual collaborations

Business schools have the responsibility of preparing students for work in multicultural organizations and global markets. This paper examines a situated learning experience for undergraduates through a virtual collaboration between a UK university and a Brazilian university. This facilitated remote communication using social media and smart devices, allowing students from both institutions to enhance their cross-cultural management competencies. A qualitative approach was used for the research, drawing on the reflections of the tutors from both institutions, and feedback received from students in the UK and Brazil. This paper provides empirical observations regarding the use of this innovative pedagogic approach, generating discussion of the implications for teaching, thus contributing to the literature on international collaborations in cross-cultural management education

Who talks to whom about what? How interdisciplinary communication and knowledge of expertise distribution improves in integrated R&D labs

Although several studies have examined the impact of open workspaces, there is still an on-going debate about its advantages and disadvantages. Our paper contributes to this debate by shedding light on three issues: the effect of open workspaces on (1) the flow of communication along and across hierarchical lines; (2) the content of communication; and (3) the specificities of open integrated laboratories. Our findings derive from a longitudinal case in a large pharmaceutical company that has relocated some R&D teams from enclosed to multi-space offices and labs. The relocation has resulted in (a) increased interdisciplinary communication, particularly at lower hierarchical levels, (b) a shift of the location of discussions and the content of conversations and (c) an improved knowledge about expertise distribution. Practitioner Summary Communication is essential in knowledge-driven organisations. This article examines the impact of a relocation of R&D employees from enclosed to multi-space offices and labs on communication patterns. We explain how the new environment fosters interdisciplinary communication, shifts the location of discussions and increases the knowledge of expertise distribution