School building energy efficiency and NO₂ related risk of childhood asthma in England and Wales: Modelling study

Background: Climate change legislation will require dramatic increases in the energy efficiency of school buildings across the UK by 2050, which has the potential to affect air quality in schools. We assessed how different strategies for improving the energy efficiency of school buildings in England and Wales may affect asthma incidence and associated healthcare utilization costs in the future. / Methods: Indoor concentrations of traffic-related NO2 were modelled inside school buildings representing 13 climate regions in England and Wales using a building physics school stock model. We used a health impact assessment model to quantify the resulting burden of childhood asthma incidence by combining regional health and population data with exposure-response functions from a recent high-quality systematic review/meta-analysis. We compared the effects of four energy efficiency interventions consisting of combinations of retrofit and operational strategies aiming to improve indoor air quality and thermal comfort on asthma incidence and associated hospitalization costs. / Results: The highest childhood asthma incidence was found in the Thames Valley region (including London), in particular in older school buildings, while the lowest concentrations and health burdens were in the newest schools in Wales. Interventions consisting of only operational improvements or combinations of retrofit and operational strategies resulted in reductions in childhood asthma incidence (547 and 676 per annum regional average, respectively) and hospital utilization costs (£52,050 and £64,310 per annum regional average, respectively. Interventions that improved energy efficiency without operational measures resulted in higher childhood asthma incidence and hospital costs. / Conclusion: The effect of school energy efficiency retrofit on NO2 exposure and asthma incidence in schoolchildren depends critically on the use of appropriate building operation strategies. The findings from this study make several contributions to fill the knowledge gap about the impact of retrofitting schools on exposure to air pollutants and their effects on children's health

Modelling platform for schools (MPS): The development of an automated One-By-One framework for the generation of dynamic thermal simulation models of schools

The UK Government has recently committed to achieve net zero carbon status by year 2050. Schools are responsible for around 2% of the UK’s total energy consumption, and around 15% of the UK public sector’s carbon emissions. A detailed analysis of the English school building stock’s performance can help policymakers improve its energy efficiency and indoor environmental quality. Building stock modelling is a technique commonly used to quantify current and future energy demand or indoor environmental quality performance of large numbers of buildings at the neighbourhood, city, regional or national level. ‘Building-by-building’ stock modelling is a modelling technique whereby individual buildings within the stock are modelled and simulated, and performance results are aggregated and analysed at stock level. This paper presents the development of the Modelling Platform for Schools (MPS) – an automated generation of one-by-one thermal models of schools in England through the analysis and integration of a range of data (geometry, size, number of buildings within a school premises etc.) from multiple databases and tools (Edubase/Get Information About Schools, Property Data Survey Programme, Ordanance Survey and others). The study then presents an initial assessment and evaluation of the modelling procedure of the proposed platform. The model evaluation has shown that out of 15,245 schools for which sufficient data were available, nearly 50% can be modelled in an automated manner having a high level of confidence of similarity with the actual buildings. Visual comparison between automatically-generated models and actual buildings has shown that around 70% of the models were, indeed, geometrically accurate

Dynamic modelling of indoor environmental conditions for future energy retrofit scenarios across the UK school building stock

UK schoolchildren spend on average 30% of their waking lives inside schools. While indoor environmental quality (IEQ) is critical for their health and attainment, school buildings are also a key part of the UK's carbon emissions reduction strategy. To address conflicts between energy efficiency and IEQ, predictive models of UK classroom stock should incorporate energy and IEQ performance criteria across dynamic scenarios comprising energy retrofit and IEQ improvement measures. On this basis, we have developed a novel approach for auto-generation, simulation, post-processing and analysis of EnergyPlus UK classroom archetype models. Such modelling facilitates the multi-parameter evaluation of school building performance, whilst incorporating stock-wide heterogeneity and longitudinal dynamic changes. As extent of retrofit increases, decreasing incremental energy demand reduction was quantified and increasing effectiveness of passive ventilation at mitigating overheating was identified. Negative impact of South facing orientation on overheating was reduced after applying a range of IEQ improvement methods. However, low ceiling heights in 1945–1967 era classrooms impact the efficacy of these IEQ mitigations on calculated attainment, requiring design rather than mitigation strategies as a remedial solution. Strategies preventing NO2 pollution ingress could be more-effective than PM2.5, with night-time ventilation avoiding ingress during daily peaks and greater sensitivity to location. Future work shall incorporate multiple criteria into a single tool based on stakeholder preferences to improve quality of retrofit decision making

Indoor Air Quality and Overheating in UK Classrooms – an Archetype Stock Modelling Approach

Children spend a large part of their waking lives in school buildings. There is substantial evidence that poor indoor air quality (IAQ) and thermal discomfort can have detrimental impacts on the performance, wellbeing and health of schoolchildren and staff. Maintaining good IAQ while avoiding overheating in classrooms is challenging due to the unique occupancy patterns and heat properties of schools. Building stock modelling has been extensively used in recent years to quantify and evaluate performance of large numbers of buildings at various scales. This paper builds on an archetype stock modelling approach which represents the diversity of the school stock in England through an analysis of The Property Data Survey Programme (PDSP) and the Display Energy Certificates (DEC) databases. The model was used for simulating Indoor-to-Outdoor pollution ratios to estimate indoor air pollution levels (NO2, PM2.5 and CO2) and thermal comfort (overheating) in two climate areas in England: London and the West Pennines. analysis highlighted variations in classrooms' indoor CO2 levels in different seasons and explored the risk of overheating in relation to a classroom's orientation

Development of a vehicle track interaction model to predict the vibratory benefits of rail grinding in the time domain

Imperfections in the wheel-rail contact are one of the main sources of generation of railway vibrations. Consequently, it is essential to take expensive corrective maintenance measures, the results of which may be unknown. In order to assess the effectiveness of these measures, this paper develops a vehicle-track interaction model in the time domain of a curved track with presence of rail corrugation on the inner rail. To characterize the behavior of the track, a numerical finite element model is developed using ANSYS software, while the behavior of the vehicle is characterized by a unidirectional model of two masses developed with VAMPIRE PRO software. The overloads obtained with the dynamic model are applied to the numerical model and then, the vibrational response of the track is obtained. Results are validated with real data and used to assess the effectiveness of rail grinding in the reduction of wheel-rail forces and the vibration generation phenomenon.Real Herráiz, JI.; Zamorano, C.; Velarte, JL.; Blanco, AE. (2015). Development of a vehicle track interaction model to predict the vibratory benefits of rail grinding in the time domain. Journal of Modern Transportation. 23(3):189-201. doi:10.1007/s40534-015-0078-yS189201233Grassie SL, Kalousek J (1993) Rail corrugation: characteristics, causes and treatments. Proc Inst Mech Eng Part F: J Rail Rapid Transit 207:57–68Grassie SL (2005) Rail corrugation: advances in measurement, understanding and treatment. Wear 258:1224–1234Grassie SL (2009) Rail corrugation: characteristics, causes and treatments. Proc Inst Mech Eng Part F: J Rail Rapid Transit 223:581–596Suda Y, Komine H, Iwasa T, Terumichi Y (2002) Experimental study on mechanism of rail corrugation using corrugation simulator. Wear 253:162–171Jin XS, Wen ZF, Wang KY, Zhou ZR, Liu QY, Li CH (2006) Three-dimensional train–track model for study of rail corrugation. J Sound Vib 293(3):830–855Zhao X, Li Z, Esveld C, Dollevoet R (2007) The dynamic stress state of the wheel–rail contact. In: Proceedings of the 2nd IASME/WSEAS international conference on continuum mechanicsTorstensson P, Nielsen J (2011) Simulation of dynamic vehicle-track interaction on small radius curves. Veh Syst Dyn 49(11):1711–1732Hawari HM, Murray MH (2008) Effects of train characteristics on the rate of deterioration of track roughness. J Eng Mech 134(3):234–239Ling L, Li W, Shang H, Xiao X, Wen Z, Jin X (2014) Experimental and numerical investigation of the effect of rail corrugation on the behaviour of rail fastenings. Veh Syst Dyn 52(9):1211–1231Collette C, Horodinca M, Preumont A (2009) Rotational vibration absorber for the mitigation of rail rutting corrugation. Veh Syst Dyn 47:641–659Egaña J, Viñolas J, Gil-Negrete L (2005) Effect of liquid high positive friction (HPF) modifier on wheel-rail contact and rail corrugation. Tribol Int 38:769–774Real Herraiz JI, Galisteo Cabeza A, Real T, Zamorano Martin C (2012) Study of wave barriers design for the mitigation of railway ground vibrations. J Vibroeng 14(1):408–422Real JI, Zamorano C, Hernandez C, Comendador R, Real T (2014) Computational considerations of 3-D finite element method models of railway vibration prediction in ballasted tracks. J Vibroeng 16(4):1709–1722Andersen L, Jones CJ (2001) Three-dimensional elastodynamic analysis using multiple boundary element domains. ISVR Technical Memorandum, University of Southampton, SouthamptonLópez Pita A (2006) Infraestructuras Ferroviarias. Universitat Politècnica de Catalunya, BarcelonaAlves P, Calçada R, Silva A (2011) Vibrations induced by railway traffic: influence of the mechanical properties of the train on the dynamic excitation mechanism. In: Proceedings of the 8th international conference on structural dynamics, EURODYN 2011, Leuven, BelgiumFerrara R, Leonardi G, Jourdan F (2012) Numerical modelling of train induced vibrations. In: SIIV-5th international congress—sustainability of road infrastructures, Rome, ItalyUzzal RU, Ahmed AK, Bhat RB (2013) Modelling, validation and analysis of a three-dimensional railway vehicle–track system model with linear and nonlinear track properties in the presence of wheel flats. Veh Syst Dyn 51(11):1695–1721Eadie DT, Kalousek J, Chiddick KC (2002) The role of high positive friction (HPF) modifier in the control of short pitch corrugations and related phenomena. Wear 253:185–19

Multi-coil focused EMAT for characterisation of surface-breaking defects of arbitrary orientation

Electromagnetic Acoustic Transducers (EMATs) are a useful ultrasonic tool for non-destructive evaluation in harsh environments due to their non-contact capabilities, and their ability to operate through certain coatings. This work presents a new Rayleigh wave EMAT transducer design, employing geometric focusing to improve the signal strength and detection precision of surface breaking defects. The design is robust and versatile, and can be used at frequencies centered around 1 MHz. Two coils are used in transmission mode, which allows the usage of frequency-based measurement of the defect depth. Using a 2 MHz driving signal, a focused beam spot with a width of 1.3±0.25 mm and a focal depth of 3.7±0.25 mm is measured, allowing for defect length measurements with an accuracy of±0.4 mm and detection of defects as small as 0.5 mm depth and 1 mm length. A set of four coils held under one magnet is used to find defects at orientations offset from normal to the ultrasound beam propagation direction. This EMAT has a range which allows detection of defects which propagate at angles from 16° to 170° relative to the propagation direction over the range of 0–180°, and the setup has the potential to be able to detect defects propagating at all angles relative to the wave propagation direction if two coils are alternately employed as generation coils

Study of Vibrations in a Short-Span Bridge Under Resonance Conditions Considering Train-Track Interaction

[EN] Resonance is a phenomenon of utmost importance in railways engineering, leading to vast damages both in track and vehicles. A short-span bridge has been modeled by means of a finite elements method model, calibrated and validated with real data, to study resonance vibrations induced by the passage of trains. Furthermore, the influence of vehicle speed and track damping on the vibrations registered on the rail, the sleeper and the bridge has been assessed. Different track and vehicle pathologies have been proposed and their effect on the resonance of the bridge has been evaluated.Ribes-Llario, F.; Velarte-González, JL.; Pérez-Garnes, JL.; Real Herráiz, JI. (2016). Study of Vibrations in a Short-Span Bridge Under Resonance Conditions Considering Train-Track Interaction. Latin American Journal of Solids and Structures. 13(7):1236-1249. doi:10.1590/1679-78252773S12361249137Ahlström, J., & Karlsson, B. (1999). Microstructural evaluation and interpretation of the mechanically and thermally affected zone under railway wheel flats. Wear, 232(1), 1-14. doi:10.1016/s0043-1648(99)00166-0Bian, X., Chao, C., Jin, W., & Chen, Y. (2011). A 2.5D finite element approach for predicting ground vibrations generated by vertical track irregularities. Journal of Zhejiang University-SCIENCE A, 12(12), 885-894. doi:10.1631/jzus.a11gt012Grassie, S. L., & Kalousek, J. (1993). Rail Corrugation: Characteristics, Causes and Treatments. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 207(1), 57-68. doi:10.1243/pime_proc_1993_207_227_02Gupta, A., & Singh Ahuja, A. (2014). Dynamic Analysis of Railway Bridges under High Speed Trains. Universal Journal of Mechanical Engineering, 2(6), 199-204. doi:10.13189/ujme.2014.020604Ju, S. H., & Lin, H. T. (2003). Resonance characteristics of high-speed trains passing simply supported bridges. Journal of Sound and Vibration, 267(5), 1127-1141. doi:10.1016/s0022-460x(02)01463-3Kwark, J. W., Choi, E. S., Kim, Y. J., Kim, B. S., & Kim, S. I. (2004). Dynamic behavior of two-span continuous concrete bridges under moving high-speed train. Computers & Structures, 82(4-5), 463-474. doi:10.1016/s0045-7949(03)00054-3Lu, Y., Mao, L., & Woodward, P. (2012). Frequency characteristics of railway bridge response to moving trains with consideration of train mass. Engineering Structures, 42, 9-22. doi:10.1016/j.engstruct.2012.04.007Makino, T., Yamamoto, M., & Fujimura, T. (2002). Effect of material on spalling properties of railroad wheels. Wear, 253(1-2), 284-290. doi:10.1016/s0043-1648(02)00117-5Mao, L., & Lu, Y. (2013). Critical Speed and Resonance Criteria of Railway Bridge Response to Moving Trains. Journal of Bridge Engineering, 18(2), 131-141. doi:10.1061/(asce)be.1943-5592.0000336Museros, P., Romero, M. ., Poy, A., & Alarcón, E. (2002). Advances in the analysis of short span railway bridges for high-speed lines. Computers & Structures, 80(27-30), 2121-2132. doi:10.1016/s0045-7949(02)00261-4Pal, S., Valente, C., Daniel, W., & Farjoo, M. (2012). Metallurgical and physical understanding of rail squat initiation and propagation. Wear, 284-285, 30-42. doi:10.1016/j.wear.2012.02.013Sheng, X., Jones, C. J. C., & Thompson, D. J. (2004). A theoretical model for ground vibration from trains generated by vertical track irregularities. Journal of Sound and Vibration, 272(3-5), 937-965. doi:10.1016/s0022-460x(03)00782-xSimon, S., Saulot, A., Dayot, C., Quost, X., & Berthier, Y. (2013). Tribological characterization of rail squat defects. Wear, 297(1-2), 926-942. doi:10.1016/j.wear.2012.11.011Wang, Y., Wei, Q., Shi, J., & Long, X. (2010). Resonance characteristics of two-span continuous beam under moving high speed trains. Latin American Journal of Solids and Structures, 7(2), 185-199. doi:10.1590/s1679-78252010000200005Xia, H., Zhang, N., & Guo, W. W. (2006). Analysis of resonance mechanism and conditions of train–bridge system. Journal of Sound and Vibration, 297(3-5), 810-822. doi:10.1016/j.jsv.2006.04.022Yang, Y. B., & Lin, C. W. (2005). Vehicle–bridge interaction dynamics and potential applications. Journal of Sound and Vibration, 284(1-2), 205-226. doi:10.1016/j.jsv.2004.06.03