Data Science

A new incrementally extendable thermodynamic model, CASH+, was developed, aimed at accurately describing equilibrium composition, solubility, and elemental uptake of C-A-S-H gel-like phases at varying chemical conditions in cement systems. Cement is widely used as matrix and backfill for low and intermediate level waste. Calcium-Aluminum-Silicate Hydrates (C-A-S-H) are the most important binding phases in cement. They are also responsible for the initial entrapment of radionuclides via sorption or solid solution formation mechanisms. Therefore, the thermodynamic modelling of C-A-S-H stability, solubility and interaction with radionuclides in cement porewater is crucial for understanding hydration, blending, degradation of cement-based materials and for the performance assessment of cementitious repositories.

We report on the first example of quantum coherence between the spins of muons and quadrupolar nuclei. We reveal that these entangled states are highly sensitive to a local charge environment and thus, can be deployed as a functional quantum sensor of that environment. The quantum coherence effect was observed in vanadium intermetallic compounds which adopt the A15 crystal structure, and whose members include all technologically pertinent superconductors. Furthermore ...

Rahel Wallimann, PhD student in the “Nuclide Chemistry Group”, received the first prize (AKB Foundation) of the SAPhW Poster Award at the Swiss Pharma Science Day 2022.

We report an excellent realization of the highly nonclassical incommensurate spin-density wave (SDW) state in the quantum frustrated antiferromagnetic insulator Cs₂CoBr₄. In contrast to the well-known Ising spin chain case, here the SDW is stabilized by virtue of competing planar in-chain anisotropies and frustrated interchain exchange.

The fuel used for nuclear energy production is normally enclosed in zirconium-based cladding tubes that constitute the first barrier between the radioactive material and the environment. In water-moderated reactors, cladding tubes tend to corrode, generating hydrogen as side product. The study of the hydrogen embrittlement in zirconium alloys is of high relevance for the industry.

Depending on temperature, local hydrogen concentration, and local stress conditions, different hydrogen-induced embrittlement mechanisms can be active in the cladding material: in certain conditions hydrogen in solid solution might cause material softening through a mechanism known as hydrogen enhanced localized plasticity (HELP).

With the goal of determining the conditions necessary to activate the HELP effect in zirconium alloys, samples have been evaluated by different micro-mechanical and macro-mechanical techniques. Results highlight the importance of the interplay between solid solution hydrogen and hydrides on the hardness and yield point of the tested materials.