This thesis details the development, optimisation, and clinical evaluation of a comprehensive biomedical optical monitoring device designed for the real-time, non-invasive assessment of metabolic parameters in transplantable organs. Addressing the critical need for localised, cellular-level data during ex vivo normothermic machine perfusion (NMP), the research bridges the gap between foundational optical engineering and real-world clinical application. A core focus of this work was the computational modelling and cleanroom fabrication of selective multi-cavity Fabry-Perot (MCFP) optical interference filters. Constructed from alternating dielectric layers, these thin-film stacks were meticulously tuned to achieve the precise spectral separation of excitation and emission wavelengths required for accurate fluorescence detection. Concurrently, bi-functional luminescent hydrogel sensors were synthesised, encapsulated with optimised protective overcoats, and integrated into the device for the continuous monitoring of tissue pH and oxygen (O 2 ) via dual-wavelength excitation (405 nm and 450 nm). Clinical validation was conducted during the NMP of human donor livers at the Erasmus Medical Center (EMC) across two distinct experimental models. Initial trials on a non-viable, defrosted liver confirmed the sensor’s capability to instantaneously track mechanically driven transient shifts in local oxygenation and pH. Subsequently, the platform was deployed on a viable, freshly declined human liver for over six hours, with localised optical readings continuously cross-referenced against gold-standard clinical perfusate analysis. While local O 2 measurements demonstrated high reliability and reflected active biological recovery, pH monitoring faced analytical challenges from hydrogel swelling, blood diffusion barriers, and photobleaching. Notably, UV excitation (405 nm) induced an exponential signal drift, whereas blue light excitation (450 nm) proved significantly more robust for continuous tracking. Ultimately, these trials successfully validated the device’s fundamental architecture, demonstrating strong proof-of-concept capabilities while identifying targeted modifications to enhance long-term clinical transplant monitoring. ... Read more

Completely positive functions are an extension of completely positive matrices. They are known to characterize maximal spherical codes and maximum-density distance-avoiding subsets of Rn and certain compact metric spaces. This thesis expands this framework to related classes of problems in finite measure spaces and to the sphere-packing problem. For the latter, this is sharpened to show that the optimal sphere-packing density can be approximated using Schwartz functions.
Converging hierarchies of semidefinite programming bounds on the size of optimal spherical codes are known, based on approximations of completely positive functions and the Locasz theta number of a graph. This thesis extends these hierarchies to distance-avoiding sets and similar problems and to the sphere-packing problem, and proves their convergence to the maximum density. For distance-avoiding sets, additional hierarchies, such as the moment hierarchy, are introduced and shown to be stronger than the completely positive hierarchy, hence they also converge. These bounds are investigated for Witsenhausen’s problem, which asks for the maximum fraction αn of the n-dimensional unit sphere that is coverable by a set avoiding orthogonal pairs, obtaining the best known upper bounds on αn in low dimensions.
The comparison of hierarchies for distance-avoiding sets moreover inspires a proof that the k-point bound for compact packing problems due to De Laat, Machado, Oliveira, and Vallentin is stronger than a converging completely positive hierarchy by Kuryatnikova and Vera. This proves convergence of the k-point bound. A related three-point bound is introduced for the t-almost-equiangular-set problem: finding the maximum size α(n, t) of a subset of the n-dimensional unit sphere in which every triple contains a pair with inner product t ∈ [−1, 1). An analytic solution to this bound yields an enumeration of optimal constructions for n = 2 and 3 when t ≥ 0. ... Read more

The concrete industry contributes ∼8% of global CO2 emissions, mainly from clinker production. Recycling concrete yields residual cementitious fines (RCF), enabling clinker substitution. This study investigates flash calcination as a thermal activation route to restore RCF reactivity. RCF were flash calcined (fRCF) and compared with untreated RCF and limestone powder. Chemical, mineralogical and physical analyses were performed. Flash calcination dehydrated portlandite and ettringite, reduced particle size, increased density and enhanced reactivity. Mortars with 25-100% clinker replacement by fRCF were tested in CEM I and CEM III/B at 1, 7, and 28 days. At 100% replacement, fRCF reached 16.3 MPa at 28 days. In CEM III/B, fRCF retained 99.4-101.4% of reference strength at 25-75% replacement, versus 36.9-78.7% in CEM I. Flash calcination thus increases RCF reactivity, enabling high clinker substitution, particularly in slag-containing systems. EU demolition waste can supply 75% clinker replacement in CEM III/B or 46% of total demand. ... Read more

Drawing on feminist ethics of care, and situated within an ecofeminist planning perspective, this research explores outdoor urban green space in Amsterdam as an urban infrastructure of care. Through two case studies of care space organizations and an analysis of municipal planning practices, this research investigates the embodied experiences of caregivers and the spatial and temporal burdens involved in navigating and using outdoor green spaces. The first perspective shows how care for children is organized through a municipally funded playgroup, and how this care is conducted in city playgrounds. The second perspective reflects how a privately-owned neighborhood center care for both human and more than human life.
The findings demonstrate that outdoor green spaces function as infrastructure of care not through the physical characteristics of the space alone, but through the relationships between spatial affordances, organizations, mobility networks, and the institutional and financial conditions that sustain them. The experiences of care participants reveal that accessibility extends beyond the physical boundaries of green spaces to include the journeys required to reach them, as well as the time, weather, safety, and everyday scheduling conditions that shape their use. The case studies further demonstrate how neighborhood organizations can activate existing outdoor spaces as places of care by providing social connection, purpose, flexibility, and opportunities for reciprocal participation. At the municipal level, many elements of care infrastructure are already addressed through planning for accessibility, mobility, safety, biodiversity, climate adaptation, maintenance, and participation; however, these functions remain fragmented across policies, departments, and responsibilities.
The research contributes to care-full planning by demonstrating the importance of connecting planned infrastructure with lived experiences of care. The findings suggest that planning for care requires improved coordination of existing planning priorities around these experiences of care to create the spatial, organizational, and institutional conditions that enable care to be continuously practiced, negotiated, and sustained.
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Efficient time and cost control is critical in housing construction, particularly where workflow disruptions and non-value-added activities reduce project performance. This study examines the Green Royal Housing Project in Jakarta, Indonesia, to evaluate how Lean Construction can improve delivery through waste identification, activity classification, and workflow planning. Project documents, site observations, and interviews with five key stakeholders were used to classify 87 construction activities into value-added, essential non-value-added, and non-value-added categories. The analysis identified 21 non-value-added activities, mainly related to waiting, unnecessary processes, transportation inefficiencies, and inventory problems. Their elimination reduced the projected duration from 83 to 74 weeks. An LPS-informed planning framework was then used to support lookahead planning, constraint screening, and weekly work commitments. Because a four-week delay remained, a CPM-based crashing scenario was evaluated separately as a post-lean acceleration option, reducing the duration to 66 weeks. The findings clarify Lean Construction's role in improving housing project efficiency. ... Read more