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- Jakobsson, Niklas, et al.
(author)
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Model based robustness analysis of an ion-exchange chromatography step
- 2007
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In: Journal of Chromatography A. - : Elsevier BV. - 0021-9673. ; 1138:1-2, s. 109-119
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Journal article (peer-reviewed)abstract
- Process development, optimization and robustness analysis for chromatographic separation are often entirely based on experimental work and generic knowledge. This paper describes a model-based approach that can be used to am process knowledge and assist in the robustness analysis of an ion-exchange chromatography step using a model-based approach. A kinetic dispersive model, where the steric mass action model accounts for the adsorption is used to describe column performance. Model calibration is based solely on gradient elution experiments at different gradients, flow rates, pH and column loads. The position and shape of the peaks provide enough information to calibrate the model and thus single-component experiments can be avoided. The model is calibrated to the experiments and the confidence intervals for the estimated parameters are used to account for the model error throughout the analysis. The model is used to predict the result of a robustness analysis conducted as a factorial experiment and to design a robust pooling approach. The confidence intervals are used in a "worst case" approach where the parameters for the components are set at the edge of their confidence intervals to create a worst case for the removal of impurities at each point in the factorial experiment. The pooling limit was changed to ensure product quality at every point in the factorial analysis. The predicted purities and yields were compared to the experimental results to ensure that the prediction intervals cover the experimental results. (c) 2006 Elsevier B.V. All rights reserved.
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- Sjöström, Jesper, et al.
(author)
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Teaching and learning for critical scientific literacy : communicating knowledge uncertainties, actors interplay and various discourses about chemicals
- 2014
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In: Science Education Research and Education for Sustainable Development. - : Shaker Verlag. - 9783844031508 ; , s. 37-48
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Book chapter (other academic/artistic)abstract
- The modern society can be described as a globalized risk society characterised by increasing complexity and unpredictable consequences of techno-scientific innovations and production. One example is the “chemicalisation” of our society, bodies and nature. In order to manage this, society needs educated citizens who are able to understand the complexity of the world and make value-based decisions – in both their private and professional lives. For example critical-democratic citizens – with “Bildung” – are able to value information about environmental chemicals and chemical risks. One arena with great potential for enabling critical-democratic citizenship is education. This chapter describes and problematizes teaching and learning about risk-related chemicals, such as additives, contaminants, pollution and various environmental chemicals. Such socio-chemical issues is a type of socio-scientific issues (SSI). Chemicals Education is suggested to be based on a “chemicals education triangle”, with the following three corners: (1) the nature of chemical risks, (2) the interplay between actors in “the chemical society”, and (3) pluralism and awareness regarding various “chemical discourses”. The communication inside and outside the science/chemistry classroom about the interplay between chemistry and society can be analyzed and discussed based on such a triangle.
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- Stenborg, Emelie
(author)
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Making sense of risk - An analysis of framings in media of the chemical risks of textiles, toys and paint
- 2013
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Doctoral thesis (other academic/artistic)abstract
- Chemical risks of consumer goods are a rather new concern in society. These risks are usually based on sythetic chemicals and man-made, often imperceptible and potentially devastating. These risks are reliant on knowledge claims and experiences as basis for risk judgments since, for example, chemical properties, threshold values and exposure are part of defining the risk. But risks are also defined and managed in society by different processes, including for example labelling, legislation and collective understandings of risks, that can jointly be called risk governance. One such process of particular interest when it comes to chemical risks of consumer goods is the role of the general public – as citizens, consumers or citizen-consumers. This thesis, in line with that uses theories of the risk society and the citizen-consumer. Chemical risks of consumer goods need to be visualised and brought on the agenda to become concerns in society. Media is one of the most important arenas for the public debate of risks since they are difficult to experience first-hand. However, media coverage about risks does not reflect “reality” but is constructed by effects inside and outside of the media organisation. Media coverage thus functions as framings, that in this thesis are defined as organizing ideas that suggests what to think about and how to think about it. This thesis explores framings in media of chemical risks of consumer goods. This thesis uses Swedish print media articles from the mid-1990s to 2009 as its empirical material when analysing framings of the chemical risks of consumer goods for three cases – textiles, toys and paint. The framings are divided according to a priori analytical categories of substantive (knowledge claims and experiences (scientific or non-scientific) as basis for risk judgments), procedural (processes in society that contribute to the cause, effect and solution of risk) and the citizen-consumer (how the general public is viewed in relation to risk issues) where the empirical material forms in vivo categories within these three main categories. The aim of the analysis is to understand and problematise the co-construction of chemical risks of consumer goods as concerns in society, by analyzing how framings support or contradict, and exclude or highlight different aspects of risk, and the implication of this. The conclusions are that substantive, procedural and citizen-consumer framings show dissimilar pattern for the three cases, acting as an explanation to why in some cases the chemical or the product group, in some cases the context of risk, and in some cases the governance of risk, are in focus in risk issues. The main reason behind this is to which extent the risk is viewed as managed, often by being part of risk governance, which sets conditions for how the risks are framed. However, this thesis probelmatises the governance of risk and suggest that chemical risks of consumer goods are difficult to manage. And that efforts made to create safe are rather making the limits to “safe” explicit due to the discrepancy between the measures taken to come to terms with risk and the expressions of the risk. Citizen-consumers can act as governance mechanism in themselves, suggesting that certain risks are cemented in the market place. But for some risks there is also a tendency to frame everyday practices, rather than consumption, as the link between the individual and the political. Finally, it is more tentatively concluded that, on the basis of the empirical material, the three product groups cannot be viewed as one late modern risk but are spread along a gliding scale, and that only the case of textiles fullfill all criteria of late moderrn risks – risk contestation, lack of governance, globalisation, individualisation and reflexivity. This thesis thus advances the understandings of how different aspects work together in framing risk as an issue of societal concern and what implications that has for society’s governance of risk. But it is also clear that this thesis is limited in scope and further studies are recommended for different product groups and for other audiences. In particular is there a need to study why only some risks are part of the public debate, suggestedly through analysing how different actors contribute to the co-construction of risk into societal concerns.
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