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Traditionally, critical infrastructures demand for high dependability, being the services they provide essential to human beings and the society at large. However, more recent attention to cautious usage of energy resources is changing this vision and calls for solutions accounting for appropriate multi-requirements combinations when developing a critical infrastructure. In such a context, analysis supports able to assist the designer in envisioning a satisfactory trade-off among the multi-requirements for the system at hand are highly helpful. In this paper, the focus is on the railway sector and the contribution is a stochastic model-based analysis framework to quantitatively assess trade-offs between dependability indicators and electrical energy consumption incurred by the rail switch heating system.Moving from a preliminary study that concentrated on energy consumption only, the analysis framework has been extended to become a solid support to devise appropriate tuning of the heating policy that guarantees satisfactory trade-offs between dependability and energy consumption. An evaluation campaign in a variety of climate scenarios demonstrates the feasibility and utility of the developed framework.

Power system controls are vulnerable to cyber-attacks that can seriously affect and even inhibit their operation. Such attacks may affect large portions of the power system, make repair difficult and cause huge societal impact, so pressure to ensure cyber-security of control and communication systems is now strong worldwide. Several cyber-security frameworks were developed, but it is rather difficult to anticipate adoption costs and benefits, and this hampers their generalised adoption. T his paper focuses on the outcome of two case studies (concerning the Italian power generation and the Polish transmission systems. The socio-economic impact of failures and the costs of standard adoption are estimated on an objective basis. It is up to public authorities to decide whether to require the adoption of security standards to operators in the electric system. The nature of public good of security underlines the necessity of public support for this operation, but we discuss the extent and the management of this support.

Silicon carbide/silicon rich carbide multilayers, aimed at the formation of silicon nanodots for photovoltaic applications, have been studied. The electrical properties have been investigated at the nano-scale by conductive Atomic Force Microscopy (c-AFM) and at macro-scale by temperature dependent conductivity measurements. The mixture is composed of highly conductive Si nanoclusters and moderately conductive SiC nanoclusters in a disordered matrix. The conduction mechanism takes place via band states induced by the disorder at the interface between nanodot clusters. Structural properties have been extracted by optical spectroscopy analyses. The results contribute to the understanding of the microscopical electronic mechanisms of the composite material, which is a candidate for third generation photovoltaics.

Achievement of sustainable development in light of ongoing climate change and biodiversity pressures benefits from the deployment of innovations that foster engagement and uptake across all levels, mobilises finance flows commencement to the scale of the challenge, and enables the dissemination of transition solutions that support the low carbon economy. This research investigates the relationship between the legal architecture of market mechanisms under international law and the role of private actors, and how this contributes to sustainable development. Through an exploration of how market mechanisms under the climate change and biodiversity regimes have achieved environmentally sound outcomes, been advanced in sectoral approaches, and facilitated via bilateral and multilateral trade and investment relationships, important insights are identified regarding the composition of effective law and governance architectural approaches. Leveraging experiences derived from treaty practice viewed through an interactional account of international law, this assessment elucidates the important role played by alignment of legal regimes, robust transparency measures, and complementary schemes such as stakeholder-endorsed certifications in buttressing the established measures to ensure sustainable development outcomes and contributes to understanding the role of private actors in the operationalisation of environmental agreements. Research findings suggest it is the interaction of norms across the international legal architecture, informed by relationships within and across relevant treaty systems and the general corpus of international law, and actualised through engagement with private actors as a component of market mechanisms that provides the opportunity for congruence of practice, forging of shared understandings, and normative internalisation and ownership among communities of practice that stimulates both innovative solutions and ambitious action.

Halide perovskites are the leading candidates for next-generation, low-cost optoelectronics with power conversion efficiencies well above 25%. However, operational stability remains a key challenge. Although there is an understanding that the microscale and nanoscale play a consequential role in determining the macroscopic performance and stability, significant gaps remain in the mechanistic understanding of degradation processes at the nanoscale and the mechanisms for stability in cation-alloyed systems. Nanoscale hexagonal phase impurities have been identified as problematic for operational stability, leading to both performance losses and morphological degradation. However, it is still unclear at what stage these phase impurities originate. Understanding this better is critical in order to mitigate the harmful effects of these phase impurities on performance and operational stability. Cation alloying is a commonly used technique in the field to mitigate these hexagonal phase impurities, although not without its challenges. In this thesis study, the nanoscale structural landscape of key halide perovskite compositions is studied. By taking snapshots of the perovskite at different states of the annealing process, the impact of phase impurities on device performance is characterised. Thereon, the mechanism by which composition dictates photostability in FA-rich perovskite absorber layers is studied. It is demonstrated that the composition impacts the degree of octahedral tilt, which is essential to restricting the transition to hexagonal phase impurities. Additionally, it is demonstrated that while a judicious mix of A-site cations can be used to stabilise the photoactive black phase of halide perovskites, it is challenging to achieve this homogeneously over large areas, necessitating a search for alternative or complementary approaches to stabilise perovskite via octahedral tilt. Using scanning electron diffraction (SED) studies, the spacegroup of additive-stabilised-CsPbI3 is demonstrated to be a low symmetry tilted γ-phase. Furthermore, using SED, the nanoscale structural landscape of mixed-phase CsPbI3 absorber layers is studied and it is demonstrated that both narrow-bandgap γ-phase and wide-bandgap δ-phase co-exist at the nanoscale, enabling stable and bright white-light emission. Overall, this thesis provides insights into the role of nanoscale structure in dictating the properties and behaviour of halide perovskites and offers rational guidelines for their optimisation and use in optoelectronic devices. Additionally, it is demonstrated that SED is a powerful tool for studying these materials at the atomic scale, allowing for the detailed characterisation of their structures and properties.

Self-organizing nanopatterns can enable economically competitive, industrially applicable light-harvesting platforms for thin-film solar cells. In this work, we present transparent solar cell substrates having quasiperiodic uniaxial nanowrinkle patterns with high optical haze values. The self-organized nanowrinkle template is created by controlled heat-shrinking of metal-deposited pre-stretched polystyrene sheets. A scalable UV nanoimprinting method is used to transfer the nanopatterns to glass substrates on which single-junction hydrogenated amorphous silicon p-i-n solar cells are subsequently fabricated. The structural and optical analyses of the solar cell show that the nanowrinkle pattern is replicated throughout the solar cell structure leading to enhanced absorption of light. The efficient broadband light-trapping in the nanowrinkle solar cells results in very high 18.2 mA/cm2 short-circuit current density and 9.5% energy-conversion efficiency, which respectively are 35.8% and 39.7% higher than the values obtained in flat-substrate solar cells. The cost- and time-efficient technique introduces a promising new approach to customizable light-management strategies in thin-film solar cells.

This study provides the first comprehensive overview of the sustainability performance of the hotel sector in the Himalayan region: Sagarmatha National Park and Buffer Zone, using both environmental, economic, and technical criteria. In particular, the performance of 45 buildings in this region were measured and quantified in terms of life cycle based carbon footprint, life cycle costs, heat loss rate, number of guests, energy consumption, and area. Buildings were classified into three types: traditional, semi-modern and modern. The statistical analysis included testing for significant differences between such categories by means of ANOVA, and determination of the correlation between the same parameters. Results show a significant difference between the buildings’ total carbon footprint and operation stage carbon footprint while, there is no significant difference between the buildings’ life cycle costs. Traditional buildings have on average the largest carbon footprint and life-cycle cost over the typical building lifespan of 50 years of building lifespan. The ANOVA tests highlight how heat loss rate, size of the building and number of tourists in the hotels are significantly different across the building types. A strong positive correlation is observed between environmental impact, economic impact and energy consumption for the household activities, and a negative correlation with the number of guests and building size. By considering several buildings, this study allows to draw new and more general conclusions about effective sustainability strategies in the whole hotel sector in the Himalayan region. In particular, it shows that reducing impacts in the operation stage should be highly prioritized, focusing on reducing energy consumption and heat loss and shifting to the use of renewable energy sources.

Formate production via both CO2 reduction and cellulose oxidation in a solar-driven process is achieved by a semiartificial biohybrid photocatalyst consisting of immobilized formate dehydrogenase on titanium dioxide (TiO2|FDH) producing up to 1.16±0.04 mmolformate gTiO2-1 in 24 hours. Isotopic labelling experiments with 13C-labelled substrates support the mechanism of stoichiometric formate formation through both redox half-reactions. TiO2|FDH was further immobilized on hollow glass microspheres to perform more practical floating photoreforming allowing vertical solar light illumination with optimal light exposure of the photocatalyst to real sunlight. Enzymatic cellulose depolymerization coupled to the floating photoreforming catalyst generates 0.36±0.04 mmolformate mirr-2 after 24 h. This work thus presents simultaneous solar-driven valorization of waste streams, demonstrates the advantages of biohybrid photocatalysts in photoreforming for the first time and will provide inspiration for the development of future semi-artificial waste-to-chemical conversion strategies.

Industrial symbiosis (IS) is recognized as an effective practice to support circular economy and sustainable development because it is able to enhance the technical efficiency of production processes, provided IS relationships among companies remain active over the long period. However, although it has been established that IS relationships can be vulnerable to disruptive events that reduce the willingness of companies to cooperate in IS synergies, to date few contributions to the literature focus attention on the events which lead firms to interrupt IS synergies. This paper contributes to the existing literature firstly by highlighting the disruptive events affecting the willingness of companies to cooperate in IS synergies and their causes, and secondly by developing an analytical model to assess the impact of each disruption on physical and monetary flows created among companies by the IS relationship. Specifically, an enterprise input-output (EIO) model is proposed, aimed at mapping the physical and monetary flows resulting from IS synergies among companies. Through this model, disruptive events can be modeled and their impact on the above-mentioned flows can be assessed. A numerical case example illustrates how the model works and how company managers and IS facilitators could use it to evaluate to what degree their current IS relationships may be vulnerable to perturbations. The model could therefore facilitate the design of adequate countermeasures and contribute to the development of perturbation resilient IS relationships. Furthermore, policymakers could adopt the model when designing policy actions to support IS practice.