Bending rigidity and higher order curvature terms for the hard-sphere fluid near a curved wall

In this work I derive analytic expressions for the curvature dependent fluid-substrate surface tension of a hard sphere fluid on a hard curved wall. In a first step, the curvature thermodynamic properties are found as truncated power series in the activity in terms of the known second and third order cluster integral of the hard-sphere fluid near spherical and cylindrical walls. These results are then expressed as packing fraction power series and transformed to different reference regions which is equivalent to consider different positions of the dividing surface. All the obtained series expansions are rigorous results. Based on the truncated series it is shown that the bending rigidity of the system is non-null and that higher order terms in the curvature also exist. In a second step, approximate analytic expressions for the surface tension, the Tolman length, the bending rigidity and the Gaussian rigidity as functions of the packing fraction are found by considering the known terms of the series expansion complemented with a simple fitting approach. It is found that the obtained formulas accurately describe the curvature thermodynamic properties of the system, further, they are more accurate than any of the previously published expressions.Comment: It is composed by 8 pages, 8 figure

Two hard spheres in a spherical pore: Exact analytic results in two and three dimensions

The partition function and the one- and two-body distribution functions are evaluated for two hard spheres with different sizes constrained into a spherical pore. The equivalent problem for hard disks is addressed too. We establish a relation valid for any dimension between these partition functions, second virial coefficient for inhomogeneous systems in a spherical pore, and third virial coefficients for polydisperse hard spheres mixtures. Using the established relation we were able to evaluate the cluster integral $b_{2}(V)$ related with the second virial coefficient for the Hard Disc system into a circular pore. Finally, we analyse the behaviour of the obtained expressions near the maximum density.Comment: def printed versio

Adsorption of 4^4He on a single C60_{60}

The adsorption of $^4$He inside and outside a single fullerene C$_{60}$ is studied. A physisorption potential is proposed. The energetics and structural features of C$_{60}$-$^4$He$_N$ clusters are investigated. Particular attention is paid to the growth of the highly pronounced layered density profile. The evolution towards bulk liquid and surface thickness at the free interface are discussed.Comment: 7 pages (TeX), 7 figure

Why NGOs matter for the success of sports events? The case of the America's Cup

Collaborations among companies and NGOs have been widely described in the literature. However, little has been said about how NGOs can become a key success factor for sports events. Palliating the uncertainties associated with consumer response, in this paper it is argued that NGO activist behavior is now a stronger antecedent of success in sporting events than consumer response. The America's Cup is used to illustrate how collaboration with NGOs can create value for all stakeholders and produce the desired outcome.Stakeholder Management; Value Creation; Sport Marketing; Sport events;

Fluids confined in wedges and by edges: From cluster integrals to thermodynamic properties referred to different regions

Recently, new insights in the relation between the geometry of the vessel that confines a fluid and its thermodynamic properties were traced through the study of cluster integrals for inhomogeneous fluids. In this work I analyze the thermodynamic properties of fluids confined in wedges or by edges, emphasizing on the question of the region to which these properties refer. In this context, the relations between the line-thermodynamic properties referred to different regions are derived as analytic functions of the dihedral angle $\alpha$ , for $0<\alpha<2\pi$ , which enables a unified approach to both edges and wedges. As a simple application of these results, I analyze the properties of the confined gas in the low-density regime. Finally, using recent analytic results for the second cluster integral of the confined hard sphere fluid, the low density behavior of the line thermodynamic properties is analytically studied up to order two in the density for $0<\alpha<2\pi$ and by adopting different reference regions.Comment: 8 pages, 7 figure

Structure, thermodynamic properties, and phase diagrams of few colloids confined in a spherical pore

We study a system of few colloids confined in a small spherical cavity by event driven molecular dynamics simulations in the canonical ensemble. The colloidal particles interact through a short range square-well potential, which takes into account the basic elements of attraction and excluded-volume repulsion of the interaction among colloids. We analyze the structural and thermodynamic properties of this few-body confined system in the framework of the theory of inhomogeneous fluids. Pair correlation functions and density profiles across the cavity are used to determine the structure of the system and the spatial characteristics of its inhomogeneities. Pressure on the walls, internal energy and surface quantities such as surface tension and adsorption are also analyzed for the whole range of densities, temperatures and number of particles considered. We have characterized the structure of systems from 2 to 6 confined particles as function of density and temperature, identifying the distinctive qualitative behaviors all over the thermodynamic plane $T-\rho$ in a few-particle equivalence to phase diagrams of macroscopic systems. Applying the extended law of corresponding states the square well interaction is mapped to the Asakura-Oosawa model for colloid-polymer mixtures. We link explicitly the temperature in the confined square-well fluid to the equivalent packing fraction of polymers in the Asakura-Oosawa model. Using this approach we study the confined system of few colloids in a colloid-polymer mixture.Comment: 17 pages, 2 tables, and 17 figure

An institutional sociology perspective of the implementation of activity based costing by Spanish health care institutions

According to institutional sociology, hospitals will respond to external environmental pressures and adopt Activity-Based-Costing (ABC). This theory overemphasizes conformity and fails to consider the advantages of organizational non-conformance. A conflict of interests between physicians and management leads to physician resistance to accepting ABC. This paper investigates the Spanish government's response to this resistance by creating new public foundation hospitals, and involves a case study of the Alcorcón foundation hospital. Population ecology is offered as an explanation for the emergence of new entities as a result of inert existing entities' resistance to reform.Activity based costing; ABC implementation; Health care; Institutional sociology; Spanish health care sector;

Analytical behavior of the fourth and fifth virial coefficients of a hard-sphere mixture

This paper focus on the study of the composition-dependent fourth and fifth virial coefficient of a hard-sphere binary mixture, namely, B 4(s) and B 5(s). On one side, the analytical expression of B 4(s) is revised. In particular, I analyzed the composition-independent term B4[1](s) included in B 4(s) and found a simplified form of its exact expression, which has the advantage over that previously published of highlighting the geometric properties of this term. On the other side, using a geometrical approach, I found a set of nonanalytic points of B 4(s) and B 5(s) as functions of s by analyzing each of their composition-independent terms.Fil: Urrutia, Ignacio. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes. Gerencia de Investigación y Aplicaciones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin