https://www.um.edu.mt/library/oar/handle/123456789/1182 2026-09-24T01:25:29Z 2026-09-24T01:25:29Z Luo, Wenping Zhao, Yiwei Zhang, Xiantao Tian, Xinliang Li, Xin Bugeja, Ryan Mule' Stagno, Luciano https://www.um.edu.mt/library/oar/handle/123456789/149302 2026-09-23T06:05:33Z 2026-01-01T00:00:00Z

Title: An integrated frequency-domain modelling framework for coupled response analysis of pontoon-truss offshore floating photovoltaic systems Authors: Luo, Wenping; Zhao, Yiwei; Zhang, Xiantao; Tian, Xinliang; Li, Xin; Bugeja, Ryan; Mule' Stagno, Luciano Abstract: Pontoon-truss offshore floating photovoltaic (PT-OFPV) systems with higher freeboard have been widely adopted in conceptual designs and prototype tests, effectively reducing the direct wave impact on electrical components. To provide an efficient evaluation of dynamic responses and structural integrity during preliminary design stages, this paper proposes a frequency-domain modelling framework for PT-OFPVs by combining finite element (FE) and discrete module beam (DMB) methods. The structure is divided into two parts and modelled separately according to their exposure to external loads. The superstructures above water are modelled using FE, while the substructures below water are modelled using DMB. Hydrodynamic loads are obtained through multi-body potential theory and applied to lumped mass points in the DMB model. Wind loads are incorporated via a frequency-domain drag formulation and applied to the deck nodes in the FE model. The complete numerical model is then established by coupling these two parts through shared interconnecting points, in combination with a linear mooring system. Then, several cases are simulated to validate the reliability of the potential-theory solution and the proposed coupled modelling framework. Subsequently, the dynamic responses of a PT-OFPV concept under regular and irregular environments are analyzed, including the effects of structural and mooring properties. A structural optimization strategy under the FE-assisted framework is also developed and demonstrated on the PT-OFPV platform. Results show that the proposed modelling framework accurately predicts motion responses compared with model tests. Moreover, stress analysis indicates that vertical trusses and pontoon connections experience the highest loads. The structural optimization reduces the total platform mass by approximately 29.4% and the maximum stress by about 31.8%, demonstrating the feasibility of the proposed optimization strategy.

2026-01-01T00:00:00Z Rexhausen, Aron Rothstein, Benno Yousif, Charles https://www.um.edu.mt/library/oar/handle/123456789/146139 2026-05-05T08:04:41Z 2026-01-01T00:00:00Z

Title: Evaluating sociotechnical factors influencing the feasibility of vineyard photovoltaic integration in Malta Authors: Rexhausen, Aron; Rothstein, Benno; Yousif, Charles Abstract: This study investigates the feasibility of viticultural photovoltaics (Viti-PV) in Malta — a small European island state in the Mediterranean — through a mixed-methods approach, combining a standardised questionnaire (n= 13 viticulturists) with expert interviews involving stakeholders from viticulture, energy and policy. Results show that while Viti-PV offers tangible benefits such as shading, reduced irrigation needs and income diversification to this sunny, warm and relatively dry island, adoption is constrained by high investment costs, regulatory prohibitions and concerns over landscape impacts. For policy and practice, the findings highlight the necessity of tailored financing models, regulatory adaptation and participatory pilot projects to build evidence and stakeholder confidence. Viti-PV can contribute simultaneously to renewable energy targets and viticultural climate resilience, but its implementation depends on coordinated support across technical, economic and institutional dimensions.

2026-01-01T00:00:00Z Dörnyei, Krisztina Rita Uysal-Unalan, Ilke Krauter, Victoria Weinrich, Ramona Incarnato, Loredana Karlovits, Igor Colelli, Giancarlo Chrysochou, Polymeros Camilleri Fenech, Margaret Kvalvåg Pettersen, Marit Arranz, Elena Marcos, Begonya Frigerio, Valeria Apicella, Annalisa Yildirim, Selçuk Poças, Fátima Dekker, Matthijs Johanna, Lahti Coma, Véronique Corredig, Milena https://www.um.edu.mt/library/oar/handle/123456789/145824 2026-04-22T13:25:41Z 2023-01-01T00:00:00Z

Title: Sustainable food packaging : an updated definition following a holistic approach Authors: Dörnyei, Krisztina Rita; Uysal-Unalan, Ilke; Krauter, Victoria; Weinrich, Ramona; Incarnato, Loredana; Karlovits, Igor; Colelli, Giancarlo; Chrysochou, Polymeros; Camilleri Fenech, Margaret; Kvalvåg Pettersen, Marit; Arranz, Elena; Marcos, Begonya; Frigerio, Valeria; Apicella, Annalisa; Yildirim, Selçuk; Poças, Fátima; Dekker, Matthijs; Johanna, Lahti; Coma, Véronique; Corredig, Milena Abstract: Food packaging solutions need to be redesigned to be more sustainable, but determining which solution is ‘more optimal’ is a very difficult task when considering the entire food product value chain. Previous papers paved the way toward a sustainable food packaging definition, but it is far from being commonly accepted or well usable in the broad food systems domain, which further results in uninformed choices for sustainable food packaging made by all stakeholders in the value chain: producers, distributors, practitioners and consumers. Therefore, this work aims first at giving a state-of-the-art overview of sustainable food packaging terms (38 similar terms were identified and grouped into four clusters: Sustainable, Circular, Bio and Other sustainable packaging) and definitions using systematic (narrative) review analysis and ‘controlled expert opinion feedback’ methodology. Second, it aims to offer an updated definition for sustainable food packaging, which is also specific to food packaging and be simple, coherent, easily understandable, and communicable to everybody. The applied holistic approach intends to include all aspects of the food-packaging unit, to consider food safety and packaging functionality, while taking into account different disciplines and challenges related to food packaging along the supply chain. Being a balancing act, a sustainable food packaging may not be a perfect solution, but contextual, suboptimal and in need of constant validation.

2023-01-01T00:00:00Z Aquilina, Luke Duane, Iain Faust, Wilian Sant, Tonio Farrugia, Robert N. https://www.um.edu.mt/library/oar/handle/123456789/145062 2026-03-22T22:46:25Z 2026-01-01T00:00:00Z

Title: Experimental analysis of a constant blade to jet speed ratio control for a micro-Pelton wheel turbine for use with an offshore hydro-pneumatic energy storage system Authors: Aquilina, Luke; Duane, Iain; Faust, Wilian; Sant, Tonio; Farrugia, Robert N. Abstract: Hydro-Pneumatic Energy Storage is a type of mechanical energy storage system being investigated for providing long duration energy storage which is becoming essential for integrating renewables on a wide scale. Pelton turbines are often being considered for converting the stored energy into electricity. This is due to the low specific speed requirements, resulting from the high pressure and low flowrates that characterise hydro-pneumatic systems. As opposed to conventional applications in hydro power, where variations in the operating head are small, hydro-pneumatic energy storage presents a more complex environment due to the relatively large variations in the head across the discharging cycle. This study implements a control scheme on a physical setup to maintain a constant blade-to-jet speed ratio for a grid-connected Pelton turbine. The proposed scheme increased the turbine’s overall efficiency from 62 % to 65 %, representing a 4.9 % relative improvement in recovered energy compared with the constant-speed control scheme.

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