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Betts J.C.,University of Malta | Mordike B.L.,Clausthal University of Technology | Grech M.,Malta College of Arts, Science and Technology
Surface Engineering | Year: 2010

Direct laser deposition was used to create tracks and surfaces using AISI 316 stainless steel powder blended with alumina, tungsten carbide or chromium carbide, with the aim to apply localised reinforcement to stainless steel components. Co-deposition of the powders was carried onto an AISI 316 stainless steel surface to evaluate parameters, and to produce specimens for metallography, EDX and XRD analysis and microhardness tests. Testing of the specimens produced using selected parameters included pin-on-disc wear tests, slurry pot erosion and corrosion testing. The alumina failed to produce a useful improvement to material properties. Tungsten carbide improved wear resistance by 260 times while erosion resistance was doubled; chromium carbide gave a maximum improvement of 88 time to sliding wear resistance, and a 2•3 times maximum improvement of erosion resistance. Chromium carbide-reinforced material furthermore performed well in corrosion tests. The deposition and testing of these materials is described and the outcome of the tests carried out is reported. © 2010 Maney Publishing. Source


Azzopardi B.,Malta College of Arts, Science and Technology | Azzopardi B.,Oxford Brookes University | Gabriel-Buenaventura A.,Oxford Brookes University
Energy | Year: 2014

Well integrated distributed photovoltaics (PVs) will help tomorrow's energy system become more sustainable. This paper highlights the net demand planning feasibility assessment to understand these dynamics. These dynamics underpins the technical feasibility when setting up high penetration of PVs within a new development area. Real measurements of disaggregated domestic electricity demand from three low-carbon homes and simulated PV output are used. A case study is based on a new building development in North West Bicester Eco Town, Oxfordshire, consisting of 393 homes, community and commercial units. Using simulation models and real domestic load measurements, the results show potential for demand management and energy storage. With a sensitivity analysis, the paper discusses also related energy policy aspects such as options for PV orientation aspects, the use of Electric Vehicles (EVs), the potential of Direct Current electrical installations and schemes that encourage load shifting. The paper concludes, within the context of the case study, assumptions and scenarios that, contrary to what is commonly believed, high penetration of PVs in a development area is feasible and may even reduce grid infrastructure costs. © 2014 Elsevier Ltd. Source


Azzopardi B.,Malta College of Arts, Science and Technology | Azzopardi B.,Oxford Brookes University
Progress in Photovoltaics: Research and Applications | Year: 2016

Plastic-based photovoltaic (PV) technology, also known as organic photovoltaic (OPV), has the development promise to be one of the third PV generation technologies, practically where sunlight reaches a surface area both indoors and outdoors. This paper presents the economic forecast for solar electricity using OPV technology based on a 1 kWp domestic system. With reference to OPV roll-to-roll manufacturing, the paper discusses lifetime, efficiency, and costs factors of this emerging PV technology. Taking an outlook of historic PV technology developments and reflect future anticipated technology developments, the future levelised electricity cost is calculated using system life cycle costing techniques. Grid parity at levelised electricity cost below 25 c/kWh may already be reached within 10 years' time, and the technology would have been widespread, assuming a typical southern Europe average solar irradiance of 1700 kWh/m2/year. The influence of solar irradiance and the way the module performs over long periods of time expecting various degradation levels is studied using sensitivity analysis. Eventually, the financial attractiveness to mature silicon-based PV technology may decline suddenly as financial support schemes such as the popular Feed-in-Tariffs dry out. This would give rise to other promising solutions that have already been proven to be less energy intensive and cheaper to produce but may require a different integration model than present technologies. This paper demonstrates that under no financial support schemes emerging PV technologies such as OPV will manage to attract business and further developments. © Copyright 2015 John Wiley & Sons, Ltd. Source


Gabriel-Buenaventura A.,Oxford Brookes University | Azzopardi B.,Oxford Brookes University | Azzopardi B.,Malta College of Arts, Science and Technology
Renewable and Sustainable Energy Reviews | Year: 2015

Energy recovery systems (ERSs) for internal combustion engine vehicles (ICEVs) are reviewed in the context of fuel efficiency improvement and retrofit capabilities. The paper presents technical knowledge on the potential benefits that retrofitted ERSs may achieve in carbon emissions reduction. A first distinction of ERSs is made between the sources of the energy and further sub-divided on the technique to harvest and store the energy. A critical evaluation is performed on the associated characteristics such as weight, size and cost. Finally, the paper summarizes the ERSs technologies under a number of common criteria, and finds out, that the most effective ERSs in terms of fuel efficiency are the ones more difficult to retrofit. Further research is suggested to investigate the trade-off between fuel consumption reduction and investment cost of the system. © 2014 Elsevier Ltd. All rights reserved. Source


Balzan M.V.,SantAnna School of Advanced Studies | Balzan M.V.,Malta College of Arts, Science and Technology | Bocci G.,SantAnna School of Advanced Studies | Moonen A.-C.,SantAnna School of Advanced Studies
Journal of Insect Conservation | Year: 2014

Sown wildflower strips are increasingly being established in Europe for enhancing arthropod conservation and the provision of ecosystem services, including biotic pollination and natural pest control. Here we use floral traits to identify different plant functional effect groups. Floral resources were provided in four experimental levels characterised by a cumulatively increasing flower trait diversity and vegetation stand complexity. The first level consisted of a bare control strip, whilst in each subsequent level three wildflower species with different functional traits were added (Level 0: Control; Level 1: three Apiaceae species; Level 2: three Apiaceae and three Fabaceae species; Level 3: three Apiaceae, three Fabaceae species, and Centaurea jacea (Asteraceae), Fagopyrum esculentum (Polygonaceae), Sinapis alba (Brassicaceae)). Plots with sown wildflower strip mixtures were located adjacent to experimental plots of organically-managed tomato crop, which is attacked by multiple pests and partially relies on bees for fruit production, and hence dependent on the provision of pollination and pest control services. Results obtained here show that the inclusion of functionally diverse wildflower species was associated with an augmented availability of floral resources across time, and this increased the abundance of bees and anthocorids throughout the crop season. Several natural enemy groups, such as parasitoids, coccinelids and ground-dwelling predators, were not significantly enhanced by the inclusion of additional flower traits within the strips but the presence of flower resources was important to enhance their conservation in an arable cropping system. © 2014 Springer International Publishing Switzerland. Source

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