Cities and Urban Heritage in the Face of a Changing Climate

Urbanisation is defined as the process where ever more people leave rural areas to live in cities [...

Indoor Mould Testing of a Historic University Building: UCL Chadwick Building

Indoor mould is one of the most important determinants of indoor air quality, with serious implications not only on human health, but also on the building envelope itself. This study is based on the Chadwick building, which is a late 19th century building, currently under the ownership of UCL as a workplace and school. Therefore it brings together different functions which are conventionally discussed separately in the relevant literature. This study aims to measure airborne and surface mould concentrations within the Chadwick Building, and to find out the correlations between these and the physical characteristics of the tested spaces. To this end, 3 classrooms, 3 offices, 3 laboratories, and 1 activity room were sampled to examine the airborne (active or aggressive) and surface mould concentrations. Samples were analysed for the β-N-acetylhexosaminidase (NAHA) activity to determine the fungal cell biomass at the laboratories of Mycometer in Denmark. The testing protocol also involved active particle counting, and temperature and relative humidity measurements. Offices were found to be the least mould intensive spaces, while laboratories were found to have the highest level of mould and particle intensity among all tested spaces. Based on the benchmarks previously established for residential indoor environments (currently in use by the Danish Building Institute), the results showed that most of the tested spaces did not have no mould and with a good/normal cleaning standard. Only one space and a few surfaces indicated either a minor (most likely non-building-related) mould, or a poor cleaning standard. The validity of these categories for a workplace/school should be further investigated by future research

An analysis of supply chain related graduate programmes in Europe

This is the post-print version of the Article. The official published version of the Article can be accessed from the links below. Copyright @ 2013 Emerald Group Publishing Limited.Purpose – Motivated by a lack of studies in graduate level supply chain education, this research aims to explore trends in supply chain-related graduate programmes in Europe and to propose a framework for designing such programmes. Design/methodology/approach – The authors determine “knowledge” and “skills” areas applicable to supply chain management (SCM) education and analyse supply chain-related graduate programmes published by the European Logistics Association in 2004. They revisit the same programmes in 2011 to determine the recent situation and the trends. The authors use cluster analysis to reveal the similarities and differences among these programmes. Findings – The authors find two distinct clusters: focused and diversified. Focused programmes offer modules in knowledge and skills areas apart from SCM at a negligible level and place more emphasis on SCM in 2011 when compared to 2004. Diversified programmes show a similar increase in the emphasis on SCM with more variety in the knowledge and skills areas. Research limitations/implications – The authors' findings are based on SCM programmes delivered in Europe and over two discrete time periods. Future research should seek to extend this analysis to other continents with larger samples and incorporate the industry perspective to determine the potential gap between what programmes offer and what industry requires. Practical implications – SCM-related graduate programmes continue to redefine themselves. Clustering predominantly serves the universities in re-assessing and re-engineering their programmes, helps prospective graduates in their selection process and assists managers in their recruitment practices. Originality/value – This paper establishes a baseline for assessing SCM-related graduate programmes with respect to the knowledge and skills they offer and introduces a framework that may serve as a starting point for the design and positioning of such programmes

Developing a methodology to detect mould hidden behind internal wall insulation

Unintended consequences, such as mould growth, can occur in building constructions such as internally insulated walls. As part of exploratory research, we examined whether air sampling through impaction and culture-based analysis could be used as means to detect interstitial mould. The results extracted suggest that the measurements may be affected by the coverage of mould within confined spaces and the indoor air velocity

Geometrical Effects in Determination of Fickian Mass Diffusivity of Polymers

Hydrophilicity of polymers makes them prone to moisture absorption that leads to degradation of mechanical properties. Kinetics of moisture ingress needs to be fully characterized to perform reliable designs with polymeric materials. The rate of diffusion is the essential parameter in determining the time scale of the moisture uptake in polymeric materials. The model from which the diffusion coefficient is to be determined can be mathematically complex when the viscoelastic relaxation and diffusion time scales are comparable (i.e. Deborah Number ~ l). However, Fickian type of diffusion is shown to be adequate in modeling the moisture absorption into a broad range of polymers. Most methods for determining the diffusion coefficient are based on the solution of Fick's second law in semi-infinite and slab domains from which, a closed form solution has been adapted by the American Society of Testing and Materials (ASTM). However, those techniques either do not consider the errors due to finite sample dimension or the correction factors provided are not precise enough. In addition, fabrication of samples conforming ASTM standard (i.e. length or width to thickness ratio of 100 or greater) may not be practical due to difficulties in producing and testing very thin coupons. In this study, the solution of the Fickian diffusion equation for a three-dimensional rectangular domain is utilized to generate mass gain data for geometries with length to thickness ratios ranging from l to I 00. These data are then used to demonstrate the errors introduced by the two conventional methods used to determine the diffusion coefficient for sample dimensions deviating from an infinitely wide slab. After applying the correction factor suggested by ASTM, up to 13% error is observed in the diffusion coefficient. In order to improve the prediction of diffusion coefficient, a least square curve fit method, which yields accurate predictions regardless of the sample geometry, is proposed.YesPeer reviewed and presented at the 23rd Oklahoma AIAA/ASME Symposium

Towards a procedure-optimised steerable catheter for deep-seated neurosurgery

In recent years, steerable needles have attracted significant interest in relation to minimally invasive surgery (MIS). Specifically, the flexible, programmable bevel-tip needle (PBN) concept was successfully demonstrated in vivo in an evaluation of the feasibility of convection-enhanced delivery (CED) for chemotherapeutics within the ovine model with a 2.5 mm PBN prototype. However, further size reductions are necessary for other diagnostic and therapeutic procedures and drug delivery operations involving deep-seated tissue structures. Since PBNs have a complex cross-section geometry, standard production methods, such as extrusion, fail, as the outer diameter is reduced further. This paper presents our first attempt to demonstrate a new manufacturing method for PBNs that employs thermal drawing technology. Experimental characterisation tests were performed for the 2.5 mm PBN and the new 1.3 mm thermally drawn (TD) PBN prototype described here. The results show that thermal drawing presents a significant advantage in miniaturising complex needle structures. However, the steering behaviour was affected due to the choice of material in this first attempt, a limitation which will be addressed in future work

Nano-scale Flexible Interphase in a Glass Fiber/Epoxy Resin System Obtained by Admicellar Polymerization

Organosilane coupling agents are widely used in the composites industry to improve the wetting of inorganic reinforcements by low surface energy resins. An increased wettability is often a harbinger of better mechanical properties in a structural composite. Silane coatings effectively increase the spreading of liquid matrixes over glass reinforcement by altering the surface energetics of glass, not by extensive coverage, but by eradication of the high-energy sites present in the oxide surface. Commercial sizings often applied to glass fibers contain up to 10% of the active silane agent, while the remaining 90% is a mixture of lubricants, surfactants, anti-stats, and film formers. Recent investigations have demonstrated that non-reactive components tend to remain in high concentrations within the interphase, thus weakening the resin network crosslink density and increasing the potential for water ingress. Further, sizing formulations are proprietary and designed for specific resin system, which make them expensive, consequently limiting their widespread use. In this paper, admicellar polymerization, a versatile technique to prepare elastomeric thin films of styrene-isoprene copolymer and polystyrene on the surface of random glass-fiber mats is presented. This hydrophobic coating of monolayer thickness applied to the glass fibers is not expected to disrupt the matrix cross-linking reaction; and due to its higher elastic modulus, is believed to cause a change in the stress distribution along the fiber length. Admicellar-modified reinforcements were impregnated with an epoxy resin system: EPON 815C/EPICURE 3232, and molded by Resin Transfer Molding (RTM) into disk shaped parts. Tensile strength, stiffness and interlaminar shear strength (ILSS) were measured for the flexible interphase composites, and compared to parts containing commercially sized and bare fibers. Void fraction, void size and shape distributions, as well as water diffusivity were investigated for each system.YesPeer reviewed and presented at the 18th International Conference of the Polymer processing Society