Predicted Electronic and Thermodynamic Properties of a Newly Discovered Zn_8Sb_7 Phase

A new binary compound, Zn_8Sb_7, has recently been prepared in nanoparticulate form via solution synthesis. No such phase is known in the bulk phase diagram; instead, one would expect phase separation to the good thermoelectric semiconductors ZnSb and Zn_4Sb_3. Here, density functional calculations are employed to determine the free energies of formation, including effects from vibrations and configurational disorder, of the relevant phases, yielding insight into the phase stability of Zn_8Sb_7. Band structure calculations predict Zn_8Sb_7, much like ZnSb and Zn_4Sb_3, to be an intermetallic semiconductor with similar thermoelectric properties. If sufficient entropy or surface energy exists to stabilize the bulk material, it would be stable in a limited temperature window at high temperature

Entropic Stabilization and Retrograde Solubility in Zn4Sb3

Zn4Sb3 is shown to be entropically stabilized versus decomposition to Zn and ZnSb though the effects of configurational disorder and phonon free energy. Single phase stability is predicted for a range of compositions and temperatures. Retrograde solubility of Zn is predicted on the two-phase boundary region between Zn4Sb3 and Zn. The complex temperature dependent solubility can be used to explain the variety of nanoparticle formation observed in the system: formation of ZnSb on the Sb rich side, Zn on the far Zn rich side and nano-void formation due to Zn precipitates being reabsorbed at lower temperatures.Comment: 5 pages, 5 figure

Self-driven lattice-model Monte Carlo simulations of alloy thermodynamic

Monte Carlo (MC) simulations of lattice models are a widely used way to compute thermodynamic properties of substitutional alloys. A limitation to their more widespread use is the difficulty of driving a MC simulation in order to obtain the desired quantities. To address this problem, we have devised a variety of high-level algorithms that serve as an interface between the user and a traditional MC code. The user specifies the goals sought in a high-level form that our algorithms convert into elementary tasks to be performed by a standard MC code. For instance, our algorithms permit the determination of the free energy of an alloy phase over its entire region of stability within a specified accuracy, without requiring any user intervention during the calculations. Our algorithms also enable the direct determination of composition-temperature phase boundaries without requiring the calculation of the whole free energy surface of the alloy system

The relationship between ombudsman, government and citizens: A survey analysis

Since the 1960s, ombudsmanship has become increasingly popular. Although there is a great deal of literature on ombudsmen, existing research rarely focuses on the people who actually use the ombudsman’s services. This article examines those who seek the help of ombudsmen in Belgium, and asks whether ombudsmen’s intervention has a noticeable effect on citizens’ confidence in government and public administration. Based on three surveys of 626 complainants, our analysis suggests that we should not see the ombudsman in Belgium as merely an instrument to help citizens but that they can also function as “change agents” and provide early warnings of problems in public administration. The role of ombudsmen in directly strengthening trust in government is limited at best. Furthermore, it seems that the profile of ombudsman complainants is skewed; our findings indicate that the socially disadvantaged are less likely to use the institution

Maatschappelijke stemmingen als determinant van consumentenvertrouwen en politiek vertrouwen

This study compares evolutions in consumer confidence and political trust in 11 European countries from 1985 to 2003. Both indicators tend to show a remarkable convergence. Belgium is the only country where we did not at first find the expected relation, but the relation reappeared once a period of extremely low political trust (1997-1998) was excluded. Specific crises in the economic or political subsystem thus seem to undermine the relation between consumer confidence and political trust. Our results suggest that political trust indicators contain more than a mere evaluation of the political situation, and that consumer confidence is composed of more than just economic evaluations or expectations. We thus claim that both indicators should not be considered as reflections of their respective societal subsystems (economy/politics). Consumer confidence and political trust are both reflections of a social mood, what explains their convergence.

Citizens' Blame of Politicians for Public Service Failure: Experimental Evidence about Blame Reduction through Delegation and Contracting

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordTheories of blame suggest that contracting out public service delivery reduces citizens' blame of politicians for service failure. The authors use an online experiment with 1,000 citizen participants to estimate the effects of information cues summarizing service delivery arrangements on citizens' blame of English local government politicians for poor street maintenance. Participants were randomized to one of four cues: no information about service delivery arrangements, politicians' involvement in managing delivery, delegation to a unit inside government managing delivery, and delegation through a contract with a private firm managing delivery. The politicians managing delivery cue raises blame compared to citizens having no information. However, the contract with a private firm cue does not reduce blame compared to either no information or the politicians managing delivery cue. Instead, the delegation to a unit inside government cue reduces blame compared to politicians managing delivery, suggesting that delegation to public managers, not contracting, reduces blame in this context.Funding support is acknowledged from European Community's Seventh Framework Programme, Grant no. 266887, Coordinating for Cohesion in the Public Sector of the Future

First report of multinodular pulmonary fibrosis associated with equine herpesvirus 5 in Belgium

A 20-year-old horse was evaluated for symptoms of weight loss, anorexia, fever and lethargy. Clinical examination revealed tachypnea, poor body condition and increased breath sounds on auscultation. Ultrasound showed multiple consolidations on the lungs. Thoracic radiography revealed a severe nodular pattern. The horse was treated with antibiotics, corticoids and supportive medication. Since no improvement was observed, the horse was euthanized. At necropsy, numerous coalescing fibrous nodules were present in the lungs. Histology revealed diffuse interstitial fibrosis and macrophages containing abundant eosinophilic cytoplasm and oval eosinophilic to amphophilic intranuclear inclusion bodies. Tissue samples tested positive for the presence of equine herpes virus 5 (EHV 5) on the basis of the polymerase chain reaction (PCR) test. A diagnosis of equine multinodular pulmonary fibrosis (EMPF) was made. This is the first report of EMPF in Belgium. EMPF can be suspected based on the ultrasonographic, radiographic and histological changes. EMPF is associated with EHV 5, but the etiological role of EHV 5 still remains to be proven

Interatomic potentials for mixed oxide (MOX) nuclear fuels

We extend our recently developed interatomic potentials for UO_{2} to the mixed oxide fuel system (U,Pu,Np)O_{2}. We do so by fitting against an extensive database of ab initio results as well as to experimental measurements. The applicability of these interactions to a variety of mixed environments beyond the fitting domain is also assessed. The employed formalism makes these potentials applicable across all interatomic distances without the need for any ambiguous splining to the well-established short-range Ziegler-Biersack-Littmark universal pair potential. We therefore expect these to be reliable potentials for carrying out damage simulations (and Molecular Dynamics simulations in general) in nuclear fuels of varying compositions for all relevant atomic collision energies

The free energy of mechanically unstable phases

Phase diagrams provide ‘roadmaps’ to the possible states of matter. Their determination traditionally rests on the assumption that all phases, even unstable ones, have well-defined free energies under all conditions. However, this assumption is commonly violated in condensed phases due to mechanical instabilities. This long-standing problem impedes thermodynamic database development, as pragmatic attempts at solving this problem involve delicate extrapolations that are highly nonunique and that lack an underlying theoretical justification. Here we propose an efficient computational solution to this problem that has a simple interpretation, both as a topological partitioning of atomic configuration space and as a minimally constrained physical system. Our natural scheme smoothly extends the free energy of stable phases, without relying on extrapolation, thus enabling a formal assessment of widely used extrapolation schemes