Projection of values through body ornamentation

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No papers - no birth certificate? Recommendations for registering children of refugees born in Germany

Registering a child immediately after birth is a State obligation under article 7(1) of the UN Convention on the Rights of the Child. Registration serves to identify a newborn and is a prerequisite for enjoying other rights. In practice, registering the children of refugees born in Germany often takes several months if their parents cannot adequately prove their own identity. This paper provides recommendations on how to implement the provisions of the Convention on registering births

Planetesimal Initial Mass Functions following Diffusion Regulated Gravitational Collapse

The initial mass function (IMF) of planetesimals is of key importance for understanding the initial stages of planet formation, yet theoretical predictions so far have been insufficient in explaining the variety of IMFs found in simulations. Here, we connect diffusion-tidal-shear limited planetesimal formation within the framework of a Toomre-like instability in the particle mid-plane of a protoplanetary disk to an analytic prediction for the planetesimal IMF. The shape of the IMF is set by the stability parameter $Q_\mathrm{p}$, which in turn depends on the particle Stokes number, the Toomre $Q$ value of the gas, the local dust concentration and the local diffusivity. We compare our prediction to high-resolution numerical simulations of the streaming instability and planetesimal formation via gravitational collapse. We find that our IMF prediction agrees with numerical results, and is consistent with both the `planetesimals are born big' paradigm and the power law description commonly found in simulations.Comment: Accepted in ApJ, 16 pages, 10 figures, 1 tabl

Electricity powering combustion: hydrogen engines

Hydrogen is ameans to chemically store energy. It can be used to buffer energy in a society increasingly relying on renewable but intermittent energy or as an energy vector for sustainable transportation. It is also attractive for its potential to power vehicles with (near-) zero tailpipe emissions. The use of hydrogen as an energy carrier for transport applications is mostly associated with fuel cells. However, hydrogen can also be used in an internal combustion engine (ICE). When converted to or designed for hydrogen operation, an ICE can attain high power output, high efficiency and ultra low emissions. Also, because of the possibility of bi-fuel operation, the hydrogen engine can act as an accelerator for building up a hydrogen infrastructure. The properties of hydrogen are quite different from the presently used hydrocarbon fuels, which is reflected in the design and operation of a hydrogen fueled ICE (H2ICE). These characteristics also result in more flexibility in engine control strategies and thus more routes for engine optimization. This article describes the most characteristic features of H2ICEs, the current state of H2ICE research and demonstration, and the future prospects

On observational and modelling strategies targeted at regional carbon exchange over continents

Estimating carbon exchange at regional scales is paramount to understanding feedbacks between climate and the carbon cycle, but also to verifying climate change mitigation such as emission reductions and strategies compensating for emissions such as carbon sequestration. This paper discusses evidence for a number of important shortcomings of current generation modelling frameworks designed to provide regional scale budgets from atmospheric observations. Current top-down and bottom-up approaches targeted at deriving consistent regional scale carbon exchange estimates for biospheric and anthropogenic sources and sinks are hampered by a number of issues: we show that top-down constraints using point measurements made from tall towers, although sensitive to larger spatial scales, are however influenced by local areas much more strongly than previously thought. On the other hand, classical bottom-up approaches using process information collected at the local scale, such as from eddy covariance data, need up-scaling and validation on larger scales. We therefore argue for a combination of both approaches, implicitly providing the important local scale information for the top-down constraint, and providing the atmospheric constraint for up-scaling of flux measurements. Combining these data streams necessitates quantifying their respective representation errors, which are discussed. The impact of these findings on future network design is highlighted, and some recommendations are given

3D Simulation of Cell Design Influences on Sodium–Iodine Battery Performance

This publication deals with the spatially resolved simulation of a sodium–iodine secondary battery. The anode compartment consists of molten sodium and the cathode compartment contains a high‐conductivity metal disc as electrode and an aqueous catholyte. The latter comprises iodide, triiodide, dissolved iodine, and sodium ions. A finite volume approach is proposed to model the transport processes and electrochemical reactions focusing on the positive half‐cell. The study investigates the influences of cathode length, C‐rate, electric conductivity, and molar concentrations on cell performance. It considers solubility limits and predicts diffusion limitation as the major constraint for the operating window. The presented investigations are confined to a simple cathode geometry. However, the results demonstrate the capability of the model to design sodium–iodine half‐cells