Recent progress with the vortex stabilized arc

Vortex stabilized plasma arc used to obtain spectral energy distribution dat

Best Practice in Conceptual Modelling for Environmental Software Development

Conceptual modelling is used in many fields with a varying degree of formality. In environmental applications, conceptual models are used to express relationships, explore and test ideas, check inference and causality, identify knowledge and data gaps, synchronize mental models and build consensus, and to highlight key or dominant processes. Conceptual model representations range from simple box and line interaction diagrams, through interaction representations and causal models, to complicated formal representations of the relationships between actors or entities, or between states and processes. Due to their sometimes apparent simplicity, the development and use of a conceptual model is often an attractive option when tackling an environmental problem where the system is either not well understood, or where the understanding of the system is not shared amongst stakeholders. However, we have experienced many examples where conceptual modelling has failed to live up to the promises of managing complexity and aiding decision making. This paper explores the development and application of conceptual modelling to environmental problems, and identifies a range of best practices for environmental scientists and managers that include considerations of stakeholder participation, model development and representation, integration of different and disparate conceptual models, model maturation, testing, and transition to application within the problem situation

Gauged motion in general relativity and in Kaluza-Klein theories

In a recent paper [1] a new generalization of the Killing motion, the {\it gauged motion}, has been introduced for stationary spacetimes where it was shown that the physical symmetries of such spacetimes are well described through this new symmetry. In this article after a more detailed study in the stationary case we present the definition of gauged motion for general spacetimes. The definition is based on the gauged Lie derivative induced by a threading family of observers and the relevant reparametrization invariance. We also extend the gauged motion to the case of Kaluza-Klein theories.Comment: 42 pages, revised version, typos correction along with some minor changes, Revtex forma

A non-uniqueness problem in solar hard X-ray spectroscopy

We consider the hard x-ray emission process by interaction between the electrons and the ions in the solar atmosphere. We provide the integral equations describing this process as an inverse problem in the case of uniform ionization of the plasma and of a simple but rather realistic approximation of non-uniform conditions. The singular system of the integral operators is computed analytically in the continuous case for the uniform ionization model and numerically in the case of discrete data for both uniform and non-uniform ionization conditions. By analytical arguments and analysis of the singular spectrum we point out that non-uniform ionization results in an ambiguous interpretation of the solution of the integral equation, this solution not being unique. Finally, we briefly recall that this analysis facilitates methods for recovering unique and regularized solutions from high-resolution hard x-ray spectral data soon to be forthcoming from the HESSI space mission

The connection between tectonical endowments and valley development on a Palaeo-Mesozoic block and in an area consisting of Tertiary molasse sediments (N-Hungary)

We examined the relationship between stru ctural endowments and valley development on a Palaeo-mesozoic basement complex and on a territory built up of Cainozoic molasse sediments. We made microtectonic and valley-orientation measurem ents. On the Palaeo-mesozoic terrain 100% of the valleys are structurally preformed, while on the molasse surfaces this value reached 85%