Concrete heritage : challenges in conservation

The development of concrete in the 19th & 20th centuries led to new possibilities and advancement in construction. Concrete was exploited to address the post-war needs for economical and faster construction. Significant reinforced concrete structures are recognized as cultural heritage. Long term durability problems present conservation challenges and the understanding of failure mechanisms is fundamental for restoration. The diagnosis of historic structures, materials investigation, monitoring and assessment are important steps towards the understanding of deterioration and appraisal of concrete heritage. Long-term effects of conservation and repair also need to be considered. The assessment of concrete heritage is addressed through military and industrial heritage concrete structures in Malta, including coastal structures in aggressive environments. A methodology for appraisal is proposed taking into consideration materials and structural performance and degradation mechanisms.peer-reviewe

GEMINs : potential therapeutic targets for spinal muscular atrophy?

The motor neuron degenerative disease spinal muscular atrophy (SMA) remains one of the most frequently inherited causes of infant mortality. Afflicted patients loose the survival motor neuron 1 (SMN1) gene but retain one or more copies of SMN2, a homolog that is incorrectly spliced. Primary treatment strategies for SMA aim at boosting SMN protein levels, which are insufficient in patients. SMN is known to partner with a set of diverse proteins collectively known as GEMINs to form a macromolecular complex. The SMN-GEMINs complex is indispensible for chaperoning the assembly of small nuclear ribonucleoproteins (snRNPs), which are key for pre-mRNA splicing. Pharmaceutics that alleviate the neuromuscular phenotype by restoring the fundamental function of SMN without augmenting its levels are also crucial in the development of an effective treatment. Their use as an adjunct therapy is predicted to enhance benefit to patients. Inspired by the surprising discovery revealing a premier role for GEMINs in snRNP biogenesis together with in vivo studies documenting their requirement for the correct function of the motor system, this review speculates on whether GEMINs constitute valid targets for SMA therapeutic development.peer-reviewe

Early age performance and mechanical characteristics of recycled PET fibre reinforced concrete

In this study the performance of concrete reinforced with fibres produced from waste non-biodegradable plastic, polyethylene terephthalate (PET), has been thoroughly investigated. The novelty of the study, to the authors’ knowledge, consists in the fact that fibres have been employed as directly shredded from collected waste plastic bottles, with no processing through, e.g., plastic melting and fibre spinning. Moreover, a comprehensive investigation has been herein undertaken, which ranges from the identification of the mechanical behaviour of the fibres to the assessment of their bond with the matrix and of the early age and hardened state properties of the recycled PET fibre reinforced concrete. Different types of shredded recycled PET fibres, straight and deformed, together with different fibre lengths, 30 mm and 50 mm, have been assessed, for varying percentage addition in concrete. The tensile properties and pull out characteristics of the fibres have been determined. The effects of fibres in mitigating plastic and restrained drying shrinkage cracking were then assessed and, finally, the compressive strength and the flexural performance of the fibre concrete were determined. The cracking potential of fibre-reinforced mortar thin slabs was also assessed. The use of shredded recycled PET fibres in concrete has been shown to lead to interesting improvements in performance for various fibre concrete characteristics and offers a potential alternative for this material

Creating a roadmap towards circularity in the built environment

Construction and Demolition (C&D) Waste is a priority waste stream due to the substantial amounts of such waste generated. There is a high potential for reuse and recycling of waste and byproducts. The Construction and Demolition Waste Strategy for Malta supports the transition towards a more circular economy and closes the loop of construction products life cycle. The quality of recycling and recovery of this waste stream needs to be improved, for market conditions to be developed to increase the demand for secondary raw materials. The paper reviews the strategic framework leading to the design, development and eventual implementation of National Standards for Excavation, Construction and Demolition Waste in Malta. The Standards presented, consist of two complimentary documents, developed to cover deconstruction, excavation and classification of waste and recycled aggregate. Standard SM810—Recycling-oriented Deconstruction, Controlled Excavation Works and Classification of Waste: Requirements for planning and execution, sets to prioritise the reduction of waste generation and highlights the importance of saving raw material resources. Standard SM820—Classification of Recycled Aggregate, sets out technical engineering attributes for the classification of waste aggregate, enabling its exploitation as a resource. A regulatory and legislative framework was developed for the implementation of the Standards. This important development sets the scene for the effective implementation of Circular Economy in the Construction Industry in the Maltese Islands.peer-reviewe

Education for sustainable construction

The COST Action C25 "Sustainability of Constructions - Integrated Approach to Life-time Structural Engineering" is a network of scientists and researchers from 28 European countries and the EU Joint Research Centre in Ispra. It was established to promote science-based developments in sustainable construction in Europe through research on life-time structural engineering. The COST Action has been active since 2006.COSTEuropean Science Foundatio

Alkaline Activation of Hybrid Cements Binders Based on Industrial by-Products

Environmentally friendly building materials are becoming increasingly relevant in civil engineering in view of their contribution toward sustainable development. This research is focused on hybrid geopolymer concrete (geopolymer with ordinary Portland-cement (OPC) additive) with the objective of analysing strength development. In this research, hybrid geopolymer concrete, manufactured using biomass bottom ash, fly ash and production waste from the manufacture of aluminium fluoride (silica gel) with 4 different amounts of OPC (0%, 5%, 10% and 15%) is studied. Each blend is cured at a temperature of 50 0C and the material is tested after 7, 14 and 28 days. X-ray powder diffraction and energy-dispersive X-ray spectroscopy were used as investigation methods. The purpose of research was to study the chemical composition and the strength development in hybrid geopolymer concretemade from OPC and the industrial by-products mentioned above

Developing a water strategy for sustainable irrigated agriculture in Mediterranean island communities – Insights from Malta

The future sustainability of irrigated agriculture in Mediterranean island communities faces a raft of economic, environmental and socio-economic challenges. Many of these are inextricably linked to the extreme levels of water scarcity that exist in the region. With a focus on Malta, we developed a water strategy to identify the priorities for action to support decision makers, practitioners and the agrifood industry in achieving agricultural and water resources sustainability. The methodology involved a combination of evidence synthesis, to inform the development of a Drivers-Pressures-State-Impact-Response framework. These priorities were then used to define a set of key actions under three thematic pillars of sustainability (environment, economy and society). Our analysis confirmed that irrigated agriculture in Malta is not only impacted by environmental factors such as the challenging climate and geography of the region but also strongly influenced by a range of economic (tourism development, European Union accession) and societal (population growth, environmental regulation) drivers of change. The developed strategy is underpinned by priority actions relating to improved water and soil management. The reduction of water and energy footprints in crop production, the establishment of demonstration farms and the support of policies that promote ‘value adding’ activities are examples of key priority actions for the environmental, economic and societal pillar, respectively. Regarding the scale of intervention, the analysis distinguishes research as being important for supporting many of the economy-focused actions

Ulcerated lesions as a risk factor for Henoch-Schonlein purpura nephritis

Objective: To determine the correlation between the severity of Henoch-Schonlein purpura skin manifestations and development of nephritis and to characterise the disease within the Maltese paediatric population. -- Design: A retrospective analysis of the 96 cases diagnosed with Henoch-Schonlein purpura at Mater Dei Hospital between January 2008 and January 2016. Clinical notes were reviewed and anonymised data regarding the presentation, progression and follow-up of these cases was entered into a database. -- Results: 96 cases met the inclusion criteria with a male to female ratio of 1.35:1 and with a mean age at presentation of 6.4 years (interquartile range 3.5 years). 99% had the typical rash at presentation with 75% having other associated clinical findings. Renal involvement was found in 36.5%: isolated proteinuria in 19.8%, isolated haematuria in 13.5%, haematuria, proteinuria and hypertension in 3.1% and nephrotic range proteinuria in 2% of cases. A severe rash at presentation was shown to be a prognostic indicator for renal involvement. -- Conclusion: Henoch-Schonlein purpura in the Maltese paediatric population is similar in incidence to that quoted in the literature. The majority of cases are uncomplicated and the outcome is frequently favourable. The presence of a severe rash at presentation significantly increases the risk of renal involvement and long term complications.peer-reviewe

Investigating the potential for passive cooling of ventilated roof systems in Malta

This paper explores the potential for passive cooling by manipulating a traditionally monolithic flat roof structure in Malta. This is investigated by isolating the cast in situ structural concrete slab from the topping screed, typically laid to falls, and ventilating the space. A test rig was set up under laboratory conditions where thermal performance was tested for in summer and winter. Results suggest that there is no significant contribution in winter when vents are kept closed but in summer convective cooling reduces indoor surfaces temperatures, alleviating discomfort conditions in upper floors, thus reducing the demand for cooling.peer-reviewe

THE FIRE PERFORMANCE OF LIMESTONE Characterisation Strategy for the Fire Performance of Maltese & Hungarian Limestone

Abstract Limestone is exploited as dimensional building stones for construction. Fire and high temperatures cause significant changes in physical & mineralogical properties of limestone in buildings and historic monuments. A strategy to investigate limestone is developed with reference to different limestones in Malta and in Hungary. The changes in properties of the limestones are assessed with respect to different test conditions including homogenous heating and the standard fire curve. The startegy includes an assessment of the physical parameters (density, porosity, water absorption, UPV, uniaxial compressive strength and indirect tensile strength); petrographic analysis (polarising microscope, XRD, SEM); colour and durability anlysis. A preliminary investigation of specific properties of limestone exposed to high temperatures is presented