Numerical simulation of the fire behaviour of facade equipped with aluminium composite material‐based claddings‐Model validation at large scale

The recent fire events in buildings involving combustible cladding systems have raised concerns regarding the risk that these systems can pose. Understanding such facade fires is complex as they involve a combination of various products and system. Facade fire propagation tests at ISO 13785‐1 intermediate scale were performed on different combinations of aluminium composite material (ACM) claddings and insulants. Simulations were addressed to reproduce these tests and were validated in terms of thermal conditions in the system. This allowed additional investigation and understanding of fire propagation on the facade and more accurate determination of the fire behaviour of the overall system. In this paper, the scaling influence on the fire behaviour of ACM clad systems is investigated with simulations performed to reproduce fire tests at the BS8414‐1 larger scale on three different combinations of ACM and insulants. The contributions of the cladding and insulant were numerically investigated. The fire behaviour of each component and of the overall system is validated by comparison with experiments. Simulations and tests show that the ACM cladding is the most important element driving the global fire behaviour of the systems. In particular, ACM‐PE‐based cladding systems, whatever the insulant, show extensive fire propagation while its degradation affects the integrity of the cavity.     

Reconstruction of Grenfell Tower fire. Part 2: A numerical investigation of the fire propagation and behaviour from the initial apartment to the façade

The dramatic event of the Grenfell Tower in 2017 reminds the importance of addressing fire issues as a whole and clearly highlighted one of the major roles played by the façade as fire propagation vector. To understand and analyse this disaster, numerical simulation allows particular phenomena to be evaluated more easily. The numerical model addressed for the fire behaviour of the façade system was developed using a multiscale approach and validated at different scales. In this paper, the fire behaviour of the façade and of its window frames is addressed. A computational fluid dynamics (CFD) model is used to investigate the fire spread from the initial apartment to the overall façade with different scenarios for the fire source and ventilation. Fire propagation through windows to the façade and to upper apartments is addressed. General curves representing the re-entry of flames into upper apartment are extracted from simulations. The numerical results are validated by comparison with observations from videos and pictures of the real fire. Numerical results show that whatever the initial fire location and ventilation conditions, even if the fire source is of hundreds kilowatts, it is enough to ignite the adjacent element early and to the appearance of external flames shortly after.     

Global solar radiation estimation

This paper presents the comparison between the observed and estimated values of global solar radiation on horizontal surfaces obtained from the linear Angstrom type of correlation of Rehman and Halawani [1] for 52 cities spread in 11 countries; viz. India, Egypt, Sri Lanka, Spain, Zimbabwe, Yemen, Sudan, Italy, Zambia, Hong Kong, and Malaysia. The comparisons are also made with the local linear models wherever available. The estimated values are compared with the measured values in terms of percent error, mean bias error (MBE), mean absolute bias error (MABE), root mean square error (RMSE), and mean percent error (MPE). This study finds that the model of Rehman and Halawani [1] is capable of giving estimates within an acceptable mean percent error of 5% and less for 33% of cities and between 5–10% for 50% of cities.     

Reconstruction of Grenfell Tower fire. Part 3—Numerical simulation of the Grenfell Tower disaster: Contribution to the understanding of the fire propagation and behaviour during the vertical fire spread

The dramatic event of the Grenfell Tower (June 2017), involving a combustible façade system, has raised concerns regarding the fire risk that these systems address. Indeed, as façades are complex systems, it is not straightforward to assess which part of the system is involved in the global fire behaviour. Understanding such façade fires is thus very complex as it depends on a combination of various products and system characteristics, including window frames or air gap or cavity barriers. Fire development inside the initial apartment was investigated using an appropriate CFD model with different scenarios for the fire source and ventilation conditions in a previous study. Fire propagation through the window to the external façade and to higher apartments was modelled and validated against visual observations. This paper describes CFD modelling of the complete Grenfell tower facade, and investigates vertical fire spread behaviour over the full height façade from the initial apartment. Contributions from the combustion of all the apartments' furniture, depending on window failure, and architectural details of the refurbished façade are considered in the numerical model. The modelling results are validated by comparison with photographic and video observations of the real fire.     

Unraveling Recrystallization Mechanisms Governing Texture Development from Rare-Earth Element Additions to Magnesium

Metallurgical and Materials Transactions A - The origin of texture components often associated with rare-earth element (REE) additions in wrought magnesium alloys is a long-standing problem in...     

On the Ductility of Magnesium Single Crystals at Ambient Temperature

Magnesium single crystals were loaded in plane-strain compression at ambient temperature, parallel, and normal to the c-axis. In the latter configuration, compression was applied along the 〈 \( 11\overline{2}0 \) 〉 as well as 〈 \( 10\overline{1}0 \) 〉 directions, whereby extension was confined to the c-axis owing to the plane-strain geometry. Out of the three tested orientations, only specimens compressed along the 〈 \( 11\overline{2}0 \) 〉 axis were able to deform up to a remarkable strain of ?1 demonstrating a surprisingly high ductility for pure magnesium at ambient temperature. The other two specimen orientations have depicted failure at two different low strains. The final microstructure of the ductile specimen was a polycrystalline mix of large deformed grains adjoining recrystallized regions of much finer grains, developed by means of extensive dynamic recovery. The corresponding final texture was relatively weak, and showed two orientation peaks with appreciable scatter around them.     

A Semi-Empirical Model for Predicting the Onset of Drop Formation in Stratified Horizontal Oil-Water Flow

In this study, a semi-empirical modeling approach for predicting the onset of drop formation in stratified horizontal oil-water flow is presented. The model is suggested based on a correlation for the critical wave amplitude for drop detachment proposed by Al-Wahaibi et al. (2007 Al-Wahaibi , T. , and Angeli , P. ( 2007 ). Transition between stratified and non-stratified horizontal oil-water flows. Part I: Stability analysis , Chem. Eng. Sci. , 62 ( 11 ), 2915 – 2928 .[Crossref], [Web of Science ®] , [Google Scholar]) and an experimentally derived formula of the maximum wave amplitude at different phase flow rates in stratified flows that uses previous data with different viscosity oils. The proposed model was found to satisfactorily predict published experimental data when relatively low viscosity oils were used (less than or equal to 12 mPa.s cp) but was found to over-predict the velocities necessary for drop formation for higher viscosity oils (greater than 28 mPa.s).     

Knowledge, attitude and practice of Taif University students on food poisoning

The aim of this study is to evaluate the knowledge, attitude and practice (KAP) on food poisoning of Taif University students, Saudi Arabia. A cluster random sampling technique stratified by three major discipline groups was used: “Male and health”, “Male and humanities” and “Female and humanities”. A total of 1020 were responded to a structured questionnaire, 340 from each group. Results showed over 50% of the students lack the knowledge that raw eggs and raw white cheese have high risk for food poisoning. Also over 50% have negative attitude and they believe there is no risk from eating raw egg or drinking raw milk of she camel. The response to practice questionnaires indicates good hygienic practice except that 76% of the students eat by hand rice and soup meal from one bowl shared by several persons. There was a significant difference (p < 0.05) between the mean score of knowledge, attitude and practice according to discipline and sex. The overall KAP mean score was 74.78%. However, the mean score for KAP components were 74.95%, 67.26% and 80.29% for knowledge, attitude and practice, respectively.     

Transjugular liver biopsy is safe and diagnostic for patients with congenital bleeding disorders and hepatitis C infection

The prevalence of chronic hepatitis C virus (HCV) infection among patients with severe congenital bleeding disorders is as high as 98%. Advances in HCV treatment currently result in sustained virological response rates of > or =50%. Recent recommendations have reaffirmed that liver biopsy, which provides a direct histological assessment of liver inflammation and fibrosis, is still important for accurate diagnosis and therapeutic decision making. Percutaneous liver biopsy is a simple, standardized procedure that can be performed rapidly and relatively inexpensively, and has been safely performed in patients with congenital coagulopathies. However, the safety and efficacy of the transjugular approach (transjugular liver biopsy, TJLB), recommended for patients with acquired coagulopathies, has only been minimally studied in the congenital bleeding diathesis population. We now report our institutional experience with TJLB in 13 such adult patients (mean age 33 years) with severe/mild haemophilia A/B (10); von Willebrand disease (1); factor V deficiency (1) and factor XIII deficiency (1). Data were collected by retrospective chart review and the TJLB was performed according to institutional protocol as described. Haemostasis prophylaxis was given for 1-5 days. Patients were hospitalized for < or =48 h and all tolerated the procedure without bleeding. Three patients experienced self-limited abdominal discomfort; one episode was accompanied by transient transaminaemia. Diagnostic specimens were obtained from all patients and were instrumental in the therapeutic decision-making process. We suggest that with a co-ordinated multidisciplinary approach to care, TJLB is a safe, effective and potentially cost-effective alternative to the percutaneous approach in the congenital bleeding disorders population.