Magnetocaloric properties of Fe_{2-x}T_xP (T = Ru and Rh) from electronic structure calculations and magnetisation measurements

An analysis of the magnetocaloric properties of the pure and substituted Fe2P compounds is made based on KKR-CPA electronic structure calculations and magnetisation M(H,T) measurements. The computed electronic densities of states and magnetic moments are used to calculate both the values of the electronic and magnetic entropies, which fairly agree with the experimental findings. To enlighten the magnetic properties above Curie temperature, the paramagnetic state behaviours are simulated using the disordered local moments (DLM) concept. The KKR-CPA computations show, that in Fe2P, the Fe magnetic moment of the (3f) site disappears in the DLM state, while the moment of the (3g) site is only little lowered, comparison made with the low temperature ferromagnetic state.Comment: 17 pages, 8 figures, Submitted to J. Phys.

A Systemic Approach to Multi-Party Relationship Modeling

Socio-economic systems exist in a wide variety of activity domains and are composed of multiple stakeholder groups. These groups pursue objectives which are often entirely motivated from within their local context. Domain specificities in the form of institutional design, for example the deregulation of Public Utility systems, can further fragment this context. Nevertheless, for these systems to be viable, a management subsystem that maintains a holistic view of the system is required. From a Systems perspective, this highlights the need to invest in methods that capture the interactions between the different stakeholders of the system. It is the understanding of the individual interactions that can help piece together a holistic view of the system thereby enabling system level discourse. In this paper we present a modeling technique that models industry interactions as a multi-party value realization process and takes a Systems approach in analyzing them. Every interaction is analyzed both from outside – system as a black box and from within – system as a white box. The design patterns that emerge from this whole/composite view of value realization provide the necessary foundation to analyze the working of multi-stakeholder systems. An explicit specification of these concepts is presented as Regulation Enabling Ontology, REGENT. As an example, we instantiate REGENT for the urban residential electricity market and demonstrate its effectiveness in identifying the requirements for time-based electricity supply systems

Magnetic and Electronic Properties of Ternary Uranium Antimonides UTSb2 (T = 3d-, 4d-, 5d-Electron Transition Metal).

Magnetic, electrical transport, neutron diffraction and Mossbauer measurements have been performed on a series of uranium- transition metal- antimonides UTSb2 (T=Fe, Co, Ni, Cu, Ru, Pd, Ag andAu). Most of these compounds were found to order magnetically at low temperatures and characterized as semimetallic Kondo lattices with strongly screened magnetic moments. Combined neutron diffraction and Mossbauer results allowed determination of the magnetic structures adopted in antiferromagnetic UNiSb2, UPdSb2. The magnetic behavior found in UTSb2 phases is here discussed with a special emphasis on the role of the f- p and f-d hybridization.JRC.E-Institute for Transuranium Elements (Karlsruhe

Water pricing in Italy: beyond full-cost recovery

This paper provides an overview of the Italian water management system, which is segmented by sectors and characterized by a wide plurality of management systems, operators and financing patterns. In the last 20 years, Italy has introduced far-reaching reforms of water management, which concerned in the first place urban water supply and sanitation. The most important aim was to create the basis for an autonomous and self-sufficient water industry, driving the sector out of the public budget. Financial equilibrium of water undertakings and access to market-based finance have thence dominated over other possible aims of water pricing. Other sectors, and notably irrigation, continue to follow more traditional schemes. The paper also discusses further reform opportunities in the search of using water prices as economic incentives for a more sustainable use of water resources

CRYSTAL-FIELD POTENTIALS OF PRFE2SI2 AND PRFE2GE2 AS DEDUCED FROM INELASTIC NEUTRON-SCATTERING AND SPECIFIC-HEAT MEASUREMENTS

Inelastic neutron scattering experiments and specific heat measurements have been performed on polycrystalline samples of PrFe(2)X(2) (X = Si, Ge), a tetragonal intermetallic system showing a low-temperature antiferromagnetic ordering of the Pr sublattice, with no local magnetic moment on the iron site. The temperature variation of the specific heat, and the values of the magnetic entropy, indicate for both compounds a crystal-field energy level scheme characterized by two closely spaced singlets, split by about 1 meV for X = Ge and by about 2.5 meV for X = Si, with the other levels positioned above 7 meV. These conclusions are confirmed by the observation of only one excitation peak in the magnetic neutron scattering response in this energy range. In the paramagnetic phase, the inelastic peak is centred at 2.4(1) meV for X = Si and at 0.8(1) meV for X = Ge. Below TN, the peak position shifts to 2.8(1) meV for X = Si, and to 2.7(1) meV for X = Ge. The experimental findings are explained by a crystal- and molecular-field model with two low-lying singlets, coupled by exchange in the ordered phase. The different size of the molecular field in the two compounds, with respect to the crystal-field splitting of the low-lying singlets, causes the large difference in the ordered moments of the Pr3+ ions (1.41 mu(B) for Si and 2.75 mu(B) for Ge). The asymmetric shape of the peaks in the neutron scattering function has been attributed to the presence of two branches of magnetic excitons in these crystal-field systems showing manifestly Van Vleck-induced antiferromagnetism of singlet-singlet type