Scoping study on the significance of mesh resolution vs. scenario uncertainty in the CFD modelling of residential smoke control systems

Computational fluid dynamics (CFD) modelling is a commonly applied tool adopted to support the specification and design of common corridor ventilation systems in UK residential buildings. Inputs for the CFD modelling of common corridor ventilation systems are typically premised on a ‘reasonable worst case’, i.e. no specific uncertainty quantification process is undertaken to evaluate the safety level. As such, where the performance of a specific design sits on a probability spectrum is not defined. Furthermore, mesh cell sizes adopted are typically c. 100 – 200 mm. For a large eddy simulation (LES) based CFD code, this is considered coarse for this application and creates a further uncertainty in respect of capturing key behaviours in the CFD model. Both co-existing practices summarised above create uncertainty, either due to parameter choice or the (computational fire and smoke) model. What is not clear is the relative importance of these uncertainties. This paper summarises a scoping study that subjects the noted common corridor CFD application to a probabilistic risk assessment (PRA), using the MaxEnt method. The uncertainty associated with the performance of a reference design is considered at different grid scales (achieving different ‘a posteriori’ mesh quality indicators), with the aim of quantifying the relative importance of uncertainties associated with inputs and scenarios, vs. the fidelity of the CFD model. For the specific case considered herein, it is found that parameter uncertainty has a more significant impact on the confidence of a given design solution relative to that arising from grid resolution, for grid sizes of 100 mm or less. Above this grid resolution, it was found that uncertainty associated with the model dictates. Given the specific ventilation arrangement modelled in this work care should be undertaken in generalising such conclusions

DISCUSSION: MORAL RESPONSIBILITY IN AGRICULTURAL RESEARCH

Teaching/Communication/Extension/Profession,

FINANCIAL INTERMEDIATION IN AGRICULTURE: A SUGGESTED ANALYTICAL MODEL

Agricultural Finance,

The politics of Piketty: what political science can learn from, and contribute to, the debate on Capital in the Twenty-First Century

Thomas Piketty's imposing volume has brought serious economics firmly into the mainstream of public debate on inequality, yet political science has been mostly absent from this debate. This article argues that political science has an essential contribution to make to this debate, and that Piketty's important and powerful book lacks a clear political theory. It develops this argument by first assessing and critiquing the changing nature of political science and its account of contemporary capitalism, and then suggesting how Piketty's thesis can be complemented, extended and challenged by focusing on the ways in which politics and collective action shape the economy and the distribution of income and wealth. Although Capital's principal message is that ‘capital is back’ and that without political interventions active political interventions will continue to grow, a political economy perspective would suggest another rather more fundamental critique: the very economic forces Piketty describes are embedded in institutional arrangements which can only be properly understood as political phenomena. In a sense capital itself – the central concept of the book – is almost meaningless without proper consideration of its political foundations. Even if the fact of capital accumulation may respond to an economic logic, the process is embedded in a very political logic. The examples of housing policy and the regulation, and failure to regulate, financial markets are used to illustrate these points

IMPROVING OCCUPATIONAL ENGAGEMENT FOR CHILDREN WITH EXECUTIVE DYSFUNCTION

A person\u27s ability to successfully perform complex tasks requires a higher level of thinking made possible through the successful use of executive functions. Executive functions develop over time, but typical development begins in early childhood. When children experience interruptions to development, executive dysfunction can inhibit their ability to reach their full occupational potential with play, academics, and social skill development. This scholarly project aims to promote executive function using an evidence-based approach to support occupational therapy practitioners and the children they serve with executive dysfunction

Dictionaries as Sources of Folklore Data

Roper, Jonathan (ed.): Dictionaries as Sources of Folklore Data. Folklore Fellows Communications 321. Helsinki: Academia Scientiarum Fennica, 2020, 246 p.Roper, Jonathan (ed.): Dictionaries as Sources of Folklore Data. Folklore Fellows Communications 321. Helsinki: Academia Scientiarum Fennica, 2020, 246 p

Changing the Contrast of Ektacolor Paper

Practical effects (contrast, fog, maximum density, and scale index) on the characteristic curves of Ektacolor paper were found for variations in the concentrations of sodium carbonate, potassium bromide, 6-nitrobenzimidazole nitrate (Kodak AF-71), color developing agent (Kodak CD-3), pH, and citrazinic acid (CZA) in an Ektacolor developer used on the Kodak model 11 drum processor. The effects of pH, citrazinic acid, potassium bromide were found to be significant while the effects 6-nitro benzimidazol nitrate and CD-3 were significant only in isolated insidences

Demonstrating adequate safety for a concrete column exposed to fire, using probabilistic methods

Demonstrating adequate safety for exceptional designs and new design applications requires an explicit evaluation of the safety level, considering the uncertainties associated with the design. The recently published PD 7974-7:2019 provides five routes to demonstrating adequate safety through probabilistic methods but does not include worked examples. The case study in this paper presents three state-of-the-art approaches for demonstrating achievement of an absolute safety target (acceptance concept ‘AC3’ in PD 7974-7:2019) for a concrete column in an office building with stringent reliability requirements. The case study shows how fragility curves listed by, for example, industry organizations can support probabilistic approaches and a more comprehensive understanding of design performance