University of Limerick Research Repository

Recent Submissions

  • PublicationOpen Access
    Enhanced biomethane production via hydrodynamic cavitation pretreatment and co-digestion of brown and DAF sludge
    (IWA publishing, 2025-05-01) Islam, Saiful; Ranade, Vivek
    This study introduces a co-digestion and vortex-based hydrodynamic cavitation (HC) pretreatment of brown and dissolved air flotation (DAF) sludge derived from dairy processing waste streams to enhance biomethane potential (BMP). Co-digestion experiments were carried out for varying ratios of brown-to-DAF sludge (1:1, 2%; 3:1, 4%). The BMP tests, conducted at 39 °C using a 15-reactor system with a 400 mL reaction volume and overhead stirrers, demonstrated that HC treatment elevated soluble chemical oxygen demand (sCOD) of brown and DAF sludges by over 34% after 80 passes through HC device. Combining DAF with brown sludge improved methane yields and reduced the time to reach peak BMP. Loading 2% volatile solids (VS) with a 1:1 ratio resulted in methane production exceeding 90% of theoretical BMP, surpassing individual brown and DAF sludge BMPs (73 and 84%, respectively). Maximum VS removal surpassed 85%, achieving a peak methane yield of over 717 mL/g-VS. These findings offer insights into addressing effluent treatment challenges and highlight the potential of co-digestion for enhanced waste valorisation.
  • PublicationOpen Access
    Cutting tool selection based on tool-life testing: An experimental investigation of tool wear when machining wrought and 3D printed Ti6Al4V using coated and un-coated tools
    (University of Limerick, 2024-11-30) Downey, David
    With the advent of additive manufacturing (3D printing) of titanium components in the medical, aerospace, and automotive industries, it is now possible to produce complex geometries with almost total design freedom. However, this design flexibility introduces several considerations, including surface waviness, build angle, and microstructural anisotropy resulting from the additive manufacturing process. Of particular interest is microstructural anisotropy and its impact on the mechanical/chemical properties and machinability of printed components. This anisotropy is influenced by the “angle of build”, i.e., the various angles at which a freeform geometric shape can be printed, such as for hip or femoral implants or similarly shaped parts in medical, aerospace, or automotive applications. Currently, finish-machining operations on titanium parts printed using selective laser melting (SLM) are performed with the same cutting tools used for finishing wrought titanium components. However, studies indicate that cutting forces for Ti6Al4V components manufactured via SLM can be up to 70% higher than those for wrought counterparts. Additionally, temperatures at the cutting interface of additively manufactured material can exceed those of wrought titanium, significantly impacting tool wear. Surface waviness can cause unequal material engagement with the cutting tool, leading to uneven tool wear. While the criteria for tool wear may be similar for both 3D-printed and wrought titanium materials, the wear rate can differ during machining. To address these differences, a series of machining tests was conducted to identify deficiencies in the cutting tools currently used for machining 3D-printed titanium. A total of 20 machining tests were performed, with results analyzed using an Alicona Infinite Focus G5 microscope to measure flank wear to a Vbmax of 0.150mm. The cutting tools had a standard geometry, with variations in PVD coatings to improve wear behavior and tool life. Cooling systems (compressed air, LCO2, LCO2 & MQL) were also employed to manage temperature and lubrication at the cutting tool interface. Results show that while current cutting tools from approved vendors perform well on wrought titanium, they perform poorly on 3D-printed titanium, with tool life reduced by up to ten times in terms of the number of passes. Cutting tool solutions provided by vendors and those suggested in the literature for machining 3D-printed titanium are not sufficiently aligned to allow the same tools to be used effectively for both 3D-printed and wrought titanium. This highlights the need for a deeper understanding of cutting tool wear, with the goal of developing improved cutting tool solutions specifically for machining 3D-printed titanium in the future.
  • PublicationOpen Access
    A cyber situation awareness framework for sectoral ISACs: enhancing cyber information sharing at strategic and policy levels
    (University of Limerick, 2025-11-01) Buckley, Ruth
    Information Sharing and Analysis Centres, or ISACs, are communities of organisations sharing cyber security information to improve their understanding of the threat landscape. One of the key benefits of ISAC membership to organisations is improved cyber situation awareness. However, during a number of cyber incidents involving Software as a Service (SaaS) providers, members of the Irish local government ISAC struggled to obtain or identify the cyber information necessary to manage the incident effectively. This thesis examines ISACs, particularly the benefits to members of ISACs and how the ISAC can achieve cyber situation awareness during a cyber incident. We reviewed the non-scientific and scientific material to identify the cyber information necessary to achieve awareness of cyber situations. Using focus groups, some comprised of cyber experts operating in Ireland only and another comprised of international cyber experts, we analysed the qualitative data to derive the cyber information themes required by senior decision makers. These decision makers operate at an organisation’s senior/policy level and have different cyber information needs than those operating at other decision-making levels. We used a Design Science research methodology to build a new cyber situation awareness framework based on Endsleys’ situation awareness framework. Our research findings emphasise the gaps in current practices and recommend new management practices. We advance scientific knowledge by designing and evaluating a new cyber situation awareness framework for senior decision-makers. Our research design demonstrates a rigour and generalisability due to the active participation of 34 cyber experts and leaders. Each participant is also a member of at least one ISAC operating in the EU or US.
  • PublicationOpen Access
    Understanding the barriers and enablers of babywearing using the COM-B model and the theoretical domains framework
    (Elsevier, 2025-11-04) Verrier, Diarmuid; Brown, Christopher J.
    Research suggests that ‘babywearing’ (the use of slings, wraps, and carriers) can have beneficial effects on the quality of parent-child attachment, maternal well-being, paternal responsiveness, breastfeeding behaviour, child mood, and child sleeping patterns. Recently, there has been a growth in the popularity of babywearing, but reports suggest there are significant challenges in engaging and maintaining the practice. This research used qualitative methods and concepts from behavioural science (the Theoretical Domains Framework and the COM-B model) to investigate the psychological, social, cultural, economic, and logistic factors that mothers perceive as barriers and enablers in relation to babywearing. Seventeen mothers with experience of babywearing were interviewed. They reported both positive and negative aspects of babywearing, and many factors that made babywearing easier or more difficult. Notable issues including access to babywearing equipment, access to training and support, difficulty/ease of use, convenience/empowerment relative to other baby transport solutions, physical capacity, and social pressure/support. The findings provide a rich social, motivational, and behavioural description of the factors that influence people’s decision to babywear and suggest several approaches that baby-wearing advocates could use to support their work.
  • PublicationOpen Access
    Dialogus musicus: chants and medieval polyphony inspired by the life of Catherine of Siena. Sample performance recording
    (2025-04-29) Sergent, Catherine; Donkoh, Femke; Feelye, Giovanna; Giraud, Eleanor J; Heredos, Rosemary; Mannion, Anne; Phelan, Helen; Żak-Dyndał, Ewa
    This recording contains one sample piece from the performance: Dialogus musicus: Chants and Medieval Polyphony inspired by the Life of Catherine of Siena performed by Cantoral: Irish World Academy Female Vocal Ensemble, performed on 29 April 2025 at the Black Abbey, Kilkenney. The piece is a conductus called O Sponsa Dei from the 13th century source, Worcester ADD-68.