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Various metal aggregates prepared using ionizing radiation were studied by microscopy techniques. A metal deposit onto a carbon felt obtained from solutions containing Pt and Ru was shown to consist of nanometric particles containing both metals. Another study deals with a subnanometric silver aggregate. The nuclearity of the aggregate was studied by scanning tunneling microscopy (STM). Additional information from pulse radiolysis experiments allowed the determination of the Ag73+ stoichiometry. The third material consisted of Ag/Pd submicron powders (70/30 or 75/25% w/w) used in electronics, and made of spherical bimetallic grains; X-ray diffraction showed segregation. The spatial distribution of each metal was obtained by combining space-resolved X-ray microanalysis in the transmission electron microscope, X-ray photoelectron spectroscopy and secondary ion mass spectrometry. Each grain was shown to be core/rind structured (core: pure Ag; rind: 10-15 nm thick 11% Ag/89% Pd w/w alloy).

Rising global temperature concerns drive unprecedented changes in the electrical power system like the massive deployment of intermittent renewable energy sources. Such large-scale renewables deployment requires a variety of flexibility options for the electrical power system to be operated reliably. A possibly important flexibility option is storage. Next to battery storage and pumped hydro storage, which have a comparably small storage capacity, indirect energy storage via power-to-gas (P2G) might be interesting for long-term (seasonal) storage due to its large scale energy storage potential. This dissertation studies the need for such energy storage via power-to-gas in future energy systems dominated by intermittent renewable energy sources, together with the operational impact of power-to-gas on the integrated electric power and natural gas systems. This overall goal is split in different sub-objectives: (i) Assessment of the value of electricity storage for an investor in a given electricity market. (ii) Identification of the circumstances which require electricity storage via P2G to justify the need for investing in P2G conversion. (iii) Once P2G would be installed, evaluation of the impact of such P2G units on the operation of both the electrical power and natural gas systems. Several tools are developed to study each of the above mentioned research questions. (i) Three novel cost metrics, similar to the traditional levelized cost of electricity are presented to express the value of storage in an electricity market. (ii) An energy system investment model is presented to assess the cost optimal amount of installed storage capacity, and in particular P2G, in future energy systems under different environmental constraints. (iii) A novel integrated operational energy system model comprising the electrical power and natural gas sectors has been developed to analyze the impact of P2G on the operation of the natural gas network. Applying the different cost metrics to storage technologies showed how those metrics can be used to assess the economic viability of different storage technologies. However, different examples also showed that it is not useful to apply such levelized cost metrics to storage units with small energy storage reservoirs like conventional batteries. For such technologies, a market price analysis with full temporal detail is recommended. Portfolio optimization studies showed that investments in P2G are triggered by a requirement for large energy storage capacities which is typically related to long-term seasonal storage of surplus renewable generation. High shares of renewable generation could be installed as a consequence of an imposed renewable target (above 70%), or when high CO2 emission prices would occur (1000€/ton and above) in combination with an absence of CO2 sequestration possibility. Once P2G is installed, it can also be used for short-term storage cycles and deliver auxiliary services to the electrical power grid. Short-term operational results indicate that the current Belgian gas network contains ample amounts of inherent flexibility to accommodate P2G integration in high renewable settings. The network can deal with possibly volatile gas injections from P2G without impacting the normal operation of conventional natural gas producers. status: published

In this study, we report about a patient with extra-uterine endometriosis (EM) in the abdominal wall muscle with evident metaplasia based on the abundant alpha smooth muscle actin (ASMA)-expressing myofibroblasts. Laparotomy excision of the abdominal wall EM was done following ultrasonographic evidence of a hypodense swelling in the right rectus abdominis, which was confirmed by MRI. Immunohistochemistry staining for ASMA and collagen I was done, with the results confirming that endometriotic stromal cells expressed both. Anterior abdominal wall endometriosis was suspected because of the patient's history of recurrent EM combined with the cyclic nature of symptoms. MRI is useful in determining the extent of the disease. In case of persisting symptoms even under hormonal treatment, surgical excision is mandatory. The expression of both ASMA and collagen I in and around EM lesions supports the notion of the metaplastic process in the course of disease development.