43 research outputs found
Once the shovel hits the ground : Evaluating the management of complex implementation processes of public-private partnership infrastructure projects with qualitative comparative analysis
Much attention is being paid to the planning of public-private partnership (PPP) infrastructure projects. The subsequent implementation phase – when the contract has been signed and the project ‘starts rolling’ – has received less attention. However, sound agreements and good intentions in project planning can easily fail in project implementation. Implementing PPP infrastructure projects is complex, but what does this complexity entail? How are projects managed, and how do public and private partners cooperate in implementation? What are effective management strategies to achieve satisfactory outcomes? This is the fi rst set of questions addressed in this thesis. Importantly, the complexity of PPP infrastructure development imposes requirements on the evaluation methods that can be applied for studying these questions. Evaluation methods that ignore complexity do not create a realistic understanding of PPP implementation processes, with the consequence that evaluations tell us little about what works and what does not, in which contexts, and why. This hampers learning from evaluations. What are the requirements for a complexity-informed evaluation method? And how does qualitative comparative analysis (QCA) meet these requirements? This is the second set of questions addressed in this thesis
Modified strontium titanates : from defect chemistry to SOFC anodes
The authors acknowledge funding from the Fuel Cells and Hydrogen Joint Undertaking under grant agreement no. 256730.Modified strontium titanates have received much attention recently for their potential as anode material in solid oxide fuel cells (SOFC). Their inherent redox stability and superior tolerance to sulphur poisoning and coking as compared to Ni based cermet anodes could improve durability of SOFC systems dramatically. Various substitution strategies can be deployed to optimise materials properties in these strontium titanates, such as electronic conductivity, electrocatalytic activity, chemical stability and sinterability, and thus mechanical strength. Substitution strategies not only cover choice and amount of substituent, but also perovskite defect chemistry, distinguishing between A-site deficiency (A1-xBO3) and cation-stoichiometry (ABO3+δ). Literature suggests distinct differences in the materials properties between the latter two compositional approaches. After discussing the defect chemistry of modified strontium titanates, this paper reviews three different A-site deficient donor (La, Y, Nb) substituted strontium titanates for their electrical behaviour and fuel cell performance. Promising performances in both electrolyte as well as anode supported cell designs have been obtained, when using hydrogen as fuel. Performances are retained after numerous redox cycles. Long term stability in sulphur and carbon containing fuels still needs to be explored in greater detail.PostprintPeer reviewe
Ocular non-Hodgkin's lymphoma: a clinical study of nine cases
BACKGROUND—Primary oculocerebral large cell malignant non-Hodgkin's lymphoma, formerly called ocular reticulum cell sarcoma, runs a uniformly fatal course. Once the central nervous system (CNS) is involved, survival without treatment is very limited. Although treatment does not substantially improve the long term survival, it provides short term improvement in these patients.
METHODS—The charts of all patients with ocular involvement of non-Hodgkin's lymphoma followed during the period 1984-93 were reviewed. The diagnosis of non-Hodgkin's lymphoma was made by different diagnostic approaches: CNS biopsy, anterior chamber tap, vitrectomy, haematology, and necropsy.
RESULTS—Eight patients had oculocerebral large cell and one had small cell non-Hodgkin's lymphoma. Five patients with pure ocular localisation had initially received steroid treatment for intermediate uveitis. First diagnosis was made on CNS biopsy in three, anterior chamber tap in one, vitreous aspirate in three, haematology in one, and necropsy in one case.
CONCLUSION—Ocular non-Hodgkin's lymphoma is a difficult diagnosis. Vitrectomy allows cytological diagnosis in most but not all cases. When no treatment is given, patients survive for only a few weeks once the CNS is involved. Although the disease is eventually fatal, treatment by means of radiotherapy, steroid administration, and vitrectomy can allow these patients to lead a normal professional and social life during the years between recurrences.