Postsynthetic modification of zirconium metal-organic frameworks

Metal-organic frameworks (MOFs) have been in the spotlight for a number of years due to their chemical and topological versatility. As MOF research has progressed, highly functionalised materials have become desirable for specific applications, and in many cases the limitations of direct synthesis have been realised. This has resulted in the search for alternative synthetic routes, with postsynthetic modification (PSM), a term used to collectively describe the functionalisation of pre-synthesised MOFs whilst maintaining their desired characteristics, becoming a topic of interest. Advances in the scope of reactions performed are reported regularly; however reactions requiring harsh conditions can result in degradation of the framework. Zirconium-based MOFs present high chemical, thermal and mechanical stabilities, offering wider opportunities for the scope of reaction conditions that can be tolerated, which has seen a number of successful examples reported. This microreview discusses pertinent examples of PSM resulting in enhanced properties for specific applications, alongside fundamental transformations, which are categorised broadly into covalent modifications, surface transformations, metalations, linker and metal exchange, and cluster modifications

Entropy of Some Models of Sparse Random Graphs With Vertex-Names

Consider the setting of sparse graphs on N vertices, where the vertices have distinct "names", which are strings of length O(log N) from a fixed finite alphabet. For many natural probability models, the entropy grows as cN log N for some model-dependent rate constant c. The mathematical content of this paper is the (often easy) calculation of c for a variety of models, in particular for various standard random graph models adapted to this setting. Our broader purpose is to publicize this particular setting as a natural setting for future theoretical study of data compression for graphs, and (more speculatively) for discussion of unorganized versus organized complexity.Comment: 31 page

Making GATT Dolphin-Safe: Trade and the Environment

The Swedish municipalities have traditionally, as suppliers of gas, electricity and district heating to end-use consumers, been one of the key actors of national energy politics. Yet, although Swedish district heating systems typically are owned by the public, neither electricity nor heat production is always under public control. This has historically imposed limitations on municipal plans for own CHP (Combined Heat and Power) plants and district heating systems. Previous research in the field have established that an organisational division between companies active in either heat or electricity supply was one of the most serious challenges for municipal engagement in energy affairs after WW2. Yet, in many cases municipal energy departments have engaged in joint cooperation projects with process industries and power companies, in order to utilize technical expertise and industrial waste heat for the build-up of the local energy system. Processes of initiating, developing and maintaining such cooperation projects - and the erection of municipal CHP plats - are focused upon here. The purpose of this research project is to describe and analyse the roles played by two municipalities (Helsingborg and Gävle) in the years 1945-1983. The specific research questions were as follows: How were different socio-technical systems for electricity and heat supply introduced and how were different alternatives received within the frames of the municipal organisations? What was the impact of competition between different alternatives on the development of the local energy systems? It shows that strategies for municipal-industrial cooperation are vital for the possibilities of municipal energy companies to come to terms with the organisational gulf between power and heat companies. It is argued that the forming of strategical alliances can illustrate how municipal organisations not always act in autonomous positions. It can rather be the other way round - it is strategies for cooperation and competition that make the municipality a key actor in the local energy system

Genus six curves, K3 surfaces, and stable pairs

A general smooth curve of genus six lies on a quintic del Pezzo surface. In \cite{AK11}, Artebani and Kond\=o construct a birational period map for genus six curves by taking ramified double covers of del Pezzo surfaces. The map is not defined for special genus six curves. In this paper, we construct a smooth Deligne-Mumford stack $\mathfrak{P}_0$ parametrizing certain stable surface-curve pairs which essentially resolves this map. Moreover, we give an explicit description of pairs in $\mathfrak{P}_0$ containing special curves.Comment: This is v2. Exposition has been improved due to referee comments. To appear in IMR