Experimental study of phase equilibria in the systems Fe-Zn-O and Fe-Zn-Si-O at metallic iron saturation

The reported experimental work on the systems Fe-Zn-O and Fe-Zn-Si-O in equilibrium with metallic iron is part of a wider research program that combines experimental and thermodynamic computer modeling techniques to characterize zinc/lead industrial slags and sinters in the system PbO-ZnO-SiO2-CaO-FeO-Fe2O3. Extensive experimental,investigations using high-temperature equilibration and quenching techniques followed by electron probe X-ray microanalysis (EPMA) were carried out. Special experimental; procedures were developed to enable accurate measurements in these ZnO-containing systems to be performed in equilibrium with metallic iron; The systems Fe-Zn-O and FeZn-Si-O were experimentally investigated in equilibrium with metallic iron in the temperature ranges 900 degreesC to 1200 degreesC (1173 to 1473 K) and from 1000 degreesC to 1350 degreesC (1273 to 1623 K), respectively. The liquidus surface in the system Fe-Zn-Si-O in equilibrium with metallic iron was characterized in the composition ranges 0 to 33 wt pet ZnO and 0 to 40 wt pet SiO2. The wustite (Fe,Zn)O, zincite (Zn,Fe)O, willemite (Zn,Fe)(2)SiO4, arid fayalite: (Fe,Zn)(2)SiO4 solid solutions in equilibrium with metallic iron were measured.

Experimental study of phase equilibria in the PbO-MgO-SiO2 system

Equilibrium phase relations in the PbO-Al2O3-SiO2 system have been investigated experimentally by means of high-temperature equilibration, quenching, and electron probe X-ray microanalysis (EPMA). The system has 21 primary phase fields including three monoxides (PbO, Al2O3, and SiO2), seven binary compounds (Al6Si2O13, PbAl2O4, PbAl12O19, Pb2Al2O5, PbSiO3, Pb2SiO4, and Pb4SiO6), and eleven ternary compounds (PbAl2Si2O8, Pb3Al10SiO20, Pb4Al2Si2O11, Pb4Al4SiO12, Pb4Al4Si3O16, Pb4Al4Si5O20, Pb5Al2Si10O28, Pb6Al2Si6O21, Pb8Al2Si4O19, Pb12Al2Si17O49, and Pb12Al2Si20O55). Three new ternary compounds, Pb4Al4SiO12, Pb4Al4Si5O20, and Pb12Al2Si17O49, were observed and characterized by EPMA. No extensive solid solution in any of the compounds was found in the present study. The liquidus isotherms were experimentally determined in most of the primary phase fields in the temperature range from 923 to 1873 K, and the ternary phase diagram of the PbO-Al2O3-SiO2 System has been constructed.

Finite element modelling of reactive fluids mixing and mineralization in pore-fluid saturated hydrothermal/sedimentary basins

We present the finite element simulations of reactive mineral carrying fluids mixing and mineralization in pore-fluid saturated hydrothermal/sedimentary basins. In particular we explore the mixing of reactive sulfide and sulfate fluids and the relevant patterns of mineralization for Load, zinc and iron minerals in the regime of temperature-gradient-driven convective flow. Since the mineralization and ore body formation may last quite a long period of time in a hydrothermal basin, it is commonly assumed that, in the geochemistry, the solutions of minerals are in an equilibrium state or near an equilibrium state. Therefore, the mineralization rate of a particular kind of mineral can be expressed as the product of the pore-fluid velocity and the equilibrium concentration of this particular kind of mineral Using the present mineralization rate of a mineral, the potential of the modern mineralization theory is illustrated by means of finite element studies related to reactive mineral-carrying fluids mixing problems in materially homogeneous and inhomogeneous porous rock basins.

Bringing the state to England: Andrew Tooke's translation of Samuel Pufendorf's 'De officio hominis et civis'

Andrew Tooke's 1691 English translation of Samuel Pufendorf's De officio hominis et civis, published as The Whole Duty of Man According to the Law of Nature, brought Pufendorf's manual fo statist natural law into English politics at a moment of temporary equilibrium in the unfinished contest between Crown and Parliament for the rights and powers of sovereignty. Drawing on the authors' re-edition of The Whole Duty of Man, this article describes and analyses a telling instance of how--by translation--the core political terms and concepts of the German natural jurist's 'absolutist' formulary were reshaped for reception in the different political culture of late seventeenth-century England.

A technological and organisational explanation for the size distribution of firms

This paper combines insights from the literature on the economics of organisation with traditional models of market structure to construct a theory of equilibrium firm size heterogeneity under the assumption of a homogenous product industry. It is possible that configurations consisting entirely of small firms (run by entrepreneurs with limited attention) and with larger firms (using managerial techniques to substitute away these limits to allow increasing returns technologies to become profitable) can arise in equilibrium. However, there also exist equilibrium configurations with the co-existence of large and small firms. The efficiency properties of these respective equilibria are discussed. Finally, the implications of an expanding market size are considered.

A comparison of the self-association behavior of the plant cyclotides kalata B1 and kalata B2 via analytical ultracentrifugation

The recently discovered cyclotides kalata B1 and kalata B2 are miniproteins containing a head-to-tail cyclized backbone and a cystine knot motif, in which disulfide bonds and the connecting backbone segments form a ring that is penetrated by the third disulfide bond. This arrangement renders the cyclotides extremely stable against thermal and enzymatic decay, making them a possible template onto which functionalities can be grafted.We have compared the hydrodynamic properties of two prototypic cyclotides, kalata B1 and kalata B2, using analytical ultracentrifugation techniques. Direct evidence for oligomerization of kalata B2 was shown by sedimentation velocity experiments in which a method for determining size distribution of polydisperse molecules in solution was employed. The shape of the oligomers appears to be spherical. Both sedimentation velocity and equilibrium experiments indicate that in phosphate buffer kalata B1 exists mainly as a monomer, even at millimolar concentrations. In contrast, at 1.6 mM, kalata B2 exists as an equilibrium mixture of monomer (30%), tetramer (42%), octamer (25%), and possibly a small proportion of higher oligomers. The results from the sedimentation equilibrium experiments show that this self-association is concentration dependent and reversible. We link our findings to the three-dimensional structures of both cyclotides, and propose two putative interaction interfaces on opposite sides of the kalata B2 molecule, one involving a hydrophobic interaction with the Phe(6), and the second involving a charge-charge interaction with the Asp(25) residue. An understanding of the factors affecting solution aggregation is of vital importance for future pharmaceutical application of these molecules.

A model of seller holdout

We model a buyer who wishes to combine objects owned by two separate sellers in order to realize higher value. Sellers are able to avoid entering into negotiations with the buyer, so that the order in which they negotiate is endogenous. Holdout occurs if at least one of the sellers is not present in the first round of negotiations. We demonstrate that complementarity of the buyer's technology is a necessary condition for equilibrium holdout. Moreover, a rise in complementarity leads to an increased likelihood of holdout, and an increased efficiency loss. Applications include patents, the land assembly problem, and mergers.

The land assembly problem revisited

As in the standard land assembly problem, a developer wants to buy two adjacent blocks of land belonging to two different owners. The value of the two blocks of land to the developer is greater than the sum of the individual values of the blocks for each owner. Unlike the land assembly literature, however, our focus is on the incentive that each lot owner has to delay the start of negotiations, rather than on the public goods nature of the problem. An incentive for delay exists, for example, when owners perceive that being last to sell will allow them to capture a larger share of the joint surplus from the development. We show that competition at point of sale can cause equilibrium delay, and that cooperation at point of sale will eliminate delay. This suggests that strategic delay is another source for the inefficient allocation of land, in addition to the public-good type externality pointed out by Grossman and Hart [Bell Journal of Economics 11 (1980) 42] and O'Flaherty [Regional Science and Urban Economics 24 (1994) 287]. (C) 2004 Elsevier B.V. All rights reserved.

Inflation targeting and macroeconomic stability in a Post Keynesian economy

This paper examines the compatibility of inflation targeting with an economy that is Post Keynesian in character. We show that in a Post Keynesian environment, policymakers can both set and achieve an inflation target without adverse consequences for the real economy, as long as an appropriate policy mix is chosen. The latitude that policymakers have in making this choice is investigated. One of our key results is that orthodox policy regimes do not provide appropriate policy mixes. Indeed, the more orthodox the policy regime becomes, the less viable is inflation targeting in a Post Keynesian economy.

Real exchange rate and elasticity of labour supply in a balance-of-payments-constrained macrodynamics

A macrodynamic model is proposed in which the real exchange rate and the elasticity of labour supply interact defining different trajectories of growth and income distribution in a developing economy. Growth depends on imports of capital goods which are paid with exports (there are no capital flows) and hence is constrained by equilibrium in current account. The role of the elasticity of labour supply is to prevent the real exchange rate from appreciating as the economy grows, thereby sustaining international competitiveness. The model allows for endogenous technological change and considers the impact of migration from the subsistence to the modern sector on the cumulative (Kaldor-Verdoorn) process of learning.

A note on the multiple partners assignment game

In the assignment game of Shapley and Shubik [Shapley, L.S., Shubik, M., 1972. The assignment game. I. The core, International journal of Game Theory 1, 11-130] agents are allowed to form one partnership at most. That paper proves that, in the context of firms and workers, given two stable payoffs for the firms there is a stable payoff which gives each firm the larger of the two amounts and also one which gives each of them the smaller amount. Analogous result applies to the workers. Sotomayor [Sotomayor, M., 1992. The multiple partners game. In: Majumdar, M. (Ed.), Dynamics and Equilibrium: Essays in Honor to D. Gale. Mcmillian, pp. 322-336] extends this analysis to the case where both types of agents may form more than one partnership and an agent`s payoff is multi-dimensional. Instead, this note concentrates in the total payoff of the agents. It is then proved the rather unexpected result that again the maximum of any pair of stable payoffs for the firms is stable but the minimum need not be, even if we restrict the multiplicity of partnerships to one of the sides. (C) 2009 Elsevier B.V. All rights reserved.

Stability property of matchings is a natural solution concept in coalitional market games

Stability of matchings was proved to be a new cooperative equilibrium concept in Sotomayor (Dynamics and equilibrium: essays in honor to D. Gale, 1992). That paper introduces the innovation of treating as multi-dimensional the payoff of a player with a quota greater than one. This is done for the many-to-many matching model with additively separable utilities, for which the stability concept is defined. It is then proved, via linear programming, that the set of stable outcomes is nonempty and it may be strictly bigger than the set of dual solutions and strictly smaller than the core. The present paper defines a general concept of stability and shows that this concept is a natural solution concept, stronger than the core concept, for a much more general coalitional game than a matching game. Instead of mutual agreements inside partnerships, the players are allowed to make collective agreements inside coalitions of any size and to distribute his labor among them. A collective agreement determines the level of labor at which the coalition operates and the division, among its members, of the income generated by the coalition. An allocation specifies a set of collective agreements for each player.

Transport-Regional Equity Issue Revisited

Almeida E. S. de, Haddad E. A. and Hewings G. J. D. Transport-regional equity issue revisited, Regional Studies. The objective of this paper is to analyse the relationship between transport and regional equity in Minas Gerais, Brazil. Furthermore, the existence of a trade-off between economic performance and regional equity is investigated as well. To do so, the paper develops a spatial computable general equilibrium model based on Brocker and Schneider`s approach of 2002 to implement comparative static analysis, explicitly incorporating iceberg transportation costs. Four activities are modelled, namely production, final demand, transportation and exports. Two production factors are assumed: labour and other factors. The model has 12 domestic regions and three external regions. Four counterfactual experiments are developed based on decreases in transportation costs due to a `distance shortening`. The main findings indicate that if the transport infrastructure improvement is focused only among poor regions, the promotion of regional equity is insignificant. If the transport infrastructure improvement links are concentrated among rich regions, there is an increase in regional income inequalities. However, if the improvements are targeted to the roads linking poor regions and rich ones, there is greater promotion of regional equity. The same result will occur when improvements are made to all road links of the state. [image omitted] Almeida E. S. de, Haddad E. A. et Hewings G. J. D. La question du rapport entre le transport et l`equilibre regional vue sous un jour nouveau, Regional Studies. Cet article cherche a analyser le rapport entre le transport et l`equilibre regional en Minas Gerais au Bresil. En outre, on examine la presence d`un echange entre la performance economoique et l`equilibre regional. Pour le faire, on construit un modele geographique de l`equilibre general a utiliser sur ordinateur fonde sur l`approche de Brockner et Schneider en 2002 afin de mettre en oeuvre une analyse statique comparative qui comprend explicitement les frais de transport iceberg. On modelise quatre activites, a savoir, la production, la demande finale, le transport et l`exportation. On fait deux suppositions quant aux facteurs de production: la main-d`oevre et d`autres facteurs. Le modele embrasse douze regions internes et trois regions externes. On fait quatre experiences paradoxales fondees sur la baisse des frais de transport due a une `reduction des distances`. Les principaux resultats indiquent que si l`amelioration de l`equipement de transport ne porte que sur les regions defavorisees, la promotion de l`equilibre regional s`avere negligeable. Si l`amelioration de l`equipement de transport focalise les regions riches, il s`avere un creusement des ecarts des revenus regionaux. Cependant, si les ameliorations ciblent les routes qui relient les regions defavorisees aux regions riches, il s`avere une plus grande promotion de l`equilibre regional. Il en va de meme pour la situation ou on a apporte des amenagements a toutes les liaisons routieres de l`etat. Modele geographique de l`equilibre general a utiliser sur ordinateur Equilibre regional Peformance economique Frais de transport Almeida E. S. de, Haddad E. A. und Hewings G. J. D. Die Wiederaufnahme der Frage von Verkehrswesen im Verhaltnis zu regionaler Fairness, Regional Studies. Dieser Aufsatz beabsichtigt, die Beziehung zwischen Verkehrswesen und regionaler Fairness in Minas Gerais (Brasilien) zu analysieren und zugleich auch das Vorkommen von Einbussen entweder bei wirtschaftlicher Leistung der regionaler Fairness zu untersuchen. Zu diesem Zwecke wird ein auf dem Ansatz von Brocker und Schneider (2002) aufbauendes raumliches komputables allgemeines Gleichgewichtsmodell entwickelt, um vergleichende statistische Analysen durchzufuhren, wobei verborgene `Eisberg`-Transportkosten ausdrucklich berucksichtigt werden. Es werden vier Unternehmenstatigk eiten aufgefuhrt: Herstellung, Nachfrage, Transportwesen und Exporte, und zwei Produktionsfaktoren vorausgesetzt: Arbeitskrafte und andere Faktoren. Das Modell umfasst zwolf Inlandsregionen und drei externe Regionen. Es werden vier gegensatzliche Experimente entwickelt, die auf einer Abnahme der Transportkosten infolge einer `Verkurzung der Entfernungen` beruhen. Die Hauptbefunde weisen darauf hin, dass die Forderung regionaler Fairness unbedeutend bleibt, wenn die Verbesserungen der Transportinfrastruktur sich nur auf minderbemittelte Regionen konzentrieren; werden die Verbesserungen der Verbindungen der Transportinfrastruktur in wohlhabenden Regionen durchgefuhrt, so nehmen regionale Einkommensunterschiede zu. Wenn die Verbesserungen jedoch auf Strassen abzielen, die wohlhabende Regionen mit weniger bemittelten verbinden, wird regionale Fairness starker gefordert. Das gleiche Ergebnis wird sich einstellen, wenn Verbesserungen an allen Strassenverbindungen des Staates vorgenommen werden. Raumliches, komputables, allgemeines Gleichgewichtsmodell Regionale Fairness Wirtschaftsleistung Transportkosten Almeida E. S. de, Haddad E. A. y Hewings G. J. D. Revisando el tema de la igualdad del transporte en las regiones, Regional Studies. El objetivo de este documento es analizar la relacion entre el transporte y la igualdad regional en Minas Gerais, Brasil. Asimismo investigamos la existencia de una compensacion entre el rendimiento economico y la igualdad regional. Para ello desarrollamos un modelo de equilibrio general computable y espacial basado en el enfoque de Brocker y Schneider en 2002 para hacer un analisis estatico y comparativo, explicitamente incorporando los costes ocultos de transporte. Se modelan cuatro actividades: la produccion, la demanda final, el transporte y las exportaciones. Suponemos que existen dos factores de produccion: mano de obra y otros factores. En este modelo, existen doce regiones internas y tres regiones externas. Desarrollamos cuatro experimentos contrafactuales basados en la disminucion de los costes de transporte debido a una `acortamiento de las distancias`. Los principales resultados indican que si la mejora de la infraestructura del transporte se centra solo entre las regiones mas pobres, el fomento de la igualdad regional es insignificante. Si los enlaces de la mejora de la infraestructura del transporte se concentran en las regiones ricas, aumentan las desigualdades de ingresos regionales. Sin embargo, si se mejoran los enlaces de carreteras entre las regiones pobres y ricas, se fomenta mejor la igualdad regional. El mismo resultado ocurre cuando se mejoran los enlaces de todas las carreteras del estado. Modelo de equilibrio general computable y espacial Igualdad regional Rendimiento economico Costes de transporte.

Price dispersion and price indexes

The traditional theory of price index numbers is based on the law of one price. But in the real world, we frequently observe the existence of an equilibrium price dispersion instead of one price of equilibrium. This article discusses the effects of price dispersion on two price indexes: the cost of living index and the consumer price index. With price dispersion and consumer searching for the lowest price, these indexes cannot be interpreted as deterministic indicators, but as stochastic indicators, and they can be biased if price dispersion is not taken into account. A measure for the bias of the consumer price index is proposed and the article ends with an estimation of the bias based on data obtained from the consumer price index calculated for the city of Sao Paulo, Brazil, from January 1988 through December 2004. The period analysed is very interesting, because it exhibits different inflationary environments: high levels and high volatility of the rates of inflation with great price dispersion until July 1994 and low and relatively stable rates of inflation with prices less dispersed after August 1994.

Debt Maturity: Is Long-Term Debt Optimal?

We model and calibrate the arguments in favor and against short-term and long-term debt. These arguments broadly include: maturity premium, sustainability, and service smoothing. We use a dynamic-equilibrium model with tax distortions and government outlays uncertainty, and model maturity as the fraction of debt that needs to be rolled over every period. In the model, the benefits of defaulting are tempered by higher future interest rates. We then calibrate our artificial economy and solve for the optimal debt maturity for Brazil as an example of a developing country and the US as an example of a mature economy. We obtain that the calibrated costs from defaulting on long-term debt more than offset costs associated with short-term debt. Therefore, short-term debt implies higher welfare levels.