CFD modelling of transient pathogen release in indoor environments due to human activity

Certain routine hospital activities have been identified as a potential source for the airborne dispersal of micro-organisms. With increasing use of CFD to model hospital situations a method of modelling this type of spread within a simple steady state model is required. Since this type of dispersal will vary with space and time a single point source would not provide adequate information to represent these sources. Instead a zonal bioaerosol source is introduced to represent the time average of the varying release from the activity. In this paper, data from experiments conducted in a bioaerosol test chamber are compared to CFD results. Numerical validation is also carried out comparing the zonal source to an equivalent transient source. The results indicate that the zonal source provides excellent comparison to the time averaged behaviour of a moving source, but greatly underestimates the maximum value at any one location

CFD modelling of a hospital ward: Assessing risk from bacteria produced from respiratory and activity sources

It has been identified that potentially pathogenic acteria, such as MRSA can be released from the skin during routine activities within hospital wards, such as bed-making, washing patients, dressing and walking. CFD is often used to study airflow patterns and ventilation regimes within hospitals, however such models tend not to consider these types of dispersal mechanisms and concentrate on respiratory transmission, using a point source at the mouth position. A zonal source is demonstrated to represent this release from activity within CFD simulations using both passive scalar and Lagrangian particle tracking. Sensitivity studies are carried out for point and zonal sources. The point source was found to not adequately represent the release of bacteria from a zone and therefore the zonal source is recommended to be used in conjunction with this type of source in order to simulate both respiratory and activity sources of bacteria

A micromorphological approach to inferring paleo-lake system phases: The case study of the Earlier Stone Age at Wonderwerk Cave, South Africa

Playa lakes are arid region ephemeral bodies of water that have been found in association with important archaeological sites. These lakes produce distinct sediments in response to changing hydrological and environmental conditions. To provide the means to more effectively study playa lake sediments, I developed an analytical protocol and a model that utilizes micromorphology and grain size distribution analysis of thin sections to identify and interpret paleo-playa lake phases preserved in intact archaeological deposits. To assess the potential of the analytical procedure, I applied it to thin sections collected from Earlier Stone Age deposits at Wonderwerk Cave, South Africa, where a playa lake system existed in proximity to the cave. The results of the study show that sediments produced during different playa lake phases can be distinguished according to a specific set of criteria identifiable through micromorphology and grain size distribution analysis

Titanium dioxide particle size effects on the degradation of organic molecules

Nanometer-size titania photocatalysts exhibit variations in chemical properties due to quantum effects on the semiconductor band gap and due to surface and crystalline properties. Degradation of organic molecules appears to be most efficient at particle sizes between 10 and 100 nm for anatase phase catalysts. This study focuses on the early chemical steps of degradation and degradation kinetics of two probe molecules, 4-methoxyresorcinol (MRC) and 1-para-anisyl-1-neopentanol (ANP) when the Millennium PC series anatase titania catalysts are used. These catalysts differ in particle size based on the amount of thermal annealing. Product formation ratios show that primary particle size does not affect the mechanism by which MRC and ANP degrade. Kinetic traces show that loss of ANP and MRC is dependent on particle size, such that PC 50 and PC 100 show the quickest loss of initial concentration of organic molecule and PC 500 shows the slowest degradation

[Re] Spike Timing Dependent Plasticity Finds the Start of Repeating Patterns in Continuous Spike Trains

A reference implementation of Spike Timing Dependent Plasticity Finds the Start of Repeating Patterns in Continuous Spike Trains, Masquelier T, Guyonneau R, Thorpe SJ, PLoS ONE 3(1): e1377, 2008. https://doi.org/10.1371/journal.pone.000137

Paying 'Due Regard'? The Impact of the Public Sector Equality Duty on Service Provision for Single Mothers

The purpose of this thesis was to examine the impact of the Public Sector Equality Duty (‘the Duty’) on the lives of single mother, local authority service users, focusing on their experiences ‘on the ground’. The discourse surrounding lone mothers has long been highly politicised, entrenched in a paradigm of dependency. This in-depth, qualitative study, undertaken between February 2013 and May 2015, used an alternative perspective of gender equality through considering the positive rights of this group. Using Bristol and Bristol City Council (BCC) as a case study, a socio-legal approach was utilised through desktop, analytical work to explore the theoretical underpinning of the Duty as ‘reflexive’ law, assess local policy and decision-making processes, and ascertain the services available to single mothers. Semi-structured interviews were conducted with 14 single mothers and 11 stakeholders to support a contextualised understanding of the way these services were used. Based on the analysis and findings of this research, BCC had established significant structures to deliver the Duty, effectively engaging local actors to improve organisational mechanisms and support equality. The Duty was identified as having a positive impact on single mother service users, potentially supporting their participation in public life. However, organisational mechanisms stimulated by the Duty were identified as vulnerable to ongoing austerity measures. This study contributes to knowledge in three respects. Firstly, it addresses a gap in evidence identified in the 2013 Governmental review of the Equality Duty, by showing how the Duty underpins transparent decision-making processes and, through localised, reflexive mechanisms informs service delivery that better meets the needs of service users. Furthermore, the systematic and detailed sociological study of the Duty’s mechanisms explores its operation ‘on the ground’ from a novel perspective. Finally, through positioning single mothers as knowledgeable social actors, it offers an alternative paradigm to existing work that portrays them as passive recipients

Model-predictive control for non-domestic buildings: a critical review and prospects

Model-predictive control (MPC) has recently excited a great deal of interest as a new control paradigm for non-domestic buildings. Since it is based on the notion of optimisation, MPC is, in principle, well-placed to deliver significant energy savings and reduction in carbon emissions compared to existing rule-based control systems. In this paper, we critically review the prospects for buildings MPC and, in particular, the central role of the predictive mathematical model that lies at its heart; our clear emphasis is on practical implementation rather than control-theoretic aspects, and covers the role of occupants as well as the form of the predictive model. The most appropriate structure for such a model is still an open question, which we discuss alongside the development of the initial model, and the process of updating the model during the building’s operational life. The importance of sensor placement is highlighted alongside the possibility of updating the model with occupants’ comfort perception. We conclude that there is an urgent need for research on the automated creation and updating of predictive models if MPC is to become an economically-viable control methodology for non-domestic buildings. Finally, more evidence through operating full scale buildings with MPC is required to demonstrate the viability of this method