Classical bridge functions in classical and quantum plasma liquids

Bridge functions, the missing link in the exact description of strong correlations, are indirectly extracted from specially designed molecular dynamics simulations of classical one-component plasma liquids and accurately parameterized. Their incorporation into an advanced integral equation theory description of Yukawa one-component plasma liquids and a novel dielectric formalism scheme for quantum one-component plasma liquids leads to an unprecedented agreement with available molecular dynamics simulations and new ab initio path integral Monte Carlo simulations, respectively.Comment: 6 pages, 4 figures, 2 table

Quantum version of the integral equation theory based dielectric scheme for strongly coupled electron liquids

A novel dielectric scheme is proposed for strongly coupled electron liquids that handles quantum mechanical effects beyond the random phase approximation level and treats electronic correlations within the integral equation theory of classical liquids. The self-consistent scheme features a complicated dynamic local field correction functional and its formulation is guided by ab initio path integral Monte Carlo simulations. Remarkably, our scheme is capable to provide unprecedently accurate results for the static structure factor with the exception of the Wigner crystallization vicinity, despite the absence of adjustable or empirical parameters.Comment: 8 pages, 3 figure

Testing the isomorph invariance of the bridge functions of Yukawa one-component plasmas

It has been conjectured that bridge functions remain nearly invariant along phase diagram lines of constant excess entropy for the class of R-simple liquids. In the companion paper, this hypothesis has been confirmed for Yukawa bridge functions outside the correlation void. In order to complete the testing of the invariance ansatz, Yukawa bridge functions are here computed inside the correlation void with the cavity distribution method and input from ultra-long molecular dynamics simulations featuring a tagged particle pair. A general methodology is developed for the design of the tagged pair interaction potential that leads to the acquisition of uniform statistics. An extrapolation technique is developed to determine the bridge function value at zero separation. The effect of different sources of errors is quantified. Yukawa bridge functions are demonstrated to be nearly isomorph invariant also in the short range. Generalization to all R-simple systems and practical implications are discussed.Comment: 19 pages, 10 figures, 3 tables, supplementary materia

Saberes ancestrales y autonomía alimentaria en fincas de agricultura familiar campesina en tres municipios de Boyacá

En este trabajo, realizado en 8 fincas de agricultura familiar campesina en Ventaquemada, 6 en Turmequé y 7 en Tibasosa (Boyacá), se aborda la autonomía alimentaria desde cuatro categorías: el autoconsumo, la agrobiodiversidad, la conservación de semillas y el autogobierno comunitario. A su vez, la autonomía alimentaria es entendida como un proceso que recupera los saberes ancestrales de las comunidades campesinas. Por este motivo, este trabajo representa un diálogo entre las categorías de análisis de la autonomía alimentaria propuestas y los saberes ancestrales que conservan las familias de estos municipios de los Andes Colombianos. La metodología utilizada fue principalmente la observación participante, apoyada en herramientas como la cartografía social, recorridos por las fincas, gráficos históricos de producción, calendarios de actividades y la elaboración de los formatos de frecuencia de consumo de alimentos y la temporalidad de cosechas. Los resultados demuestran que la mayoría de las fincas (a excepción de una) se encuentran en reconversión hacia la agroecología. Este interés ha traído como consecuencia el fortalecimiento de las cuatro categorías consideradas en el análisis de la autonomía alimentaria. Por este motivo, la agroecología, los saberes ancestrales y la autonomía alimentaria no pueden desligarse.Abstract: This work was done in 8 peasant family farming farms in Ventaquemada, 6 in Turmequé and 7 in Tibasosa (Boyacá). The food autonomy was approached from four categories: the self-consumption, agrobiodiversity, seed conservation and community self-government. At the same time, the food autonomy is understand as a process that recovers the ancestral knowledge of the peasant communities. For this reason, this work represents a dialogue between the food autonomy’s categories that were proposed and the ancestral knowledge that the families of this towns from the Colombian Andes preserve. The methodology used was mainly the participant observation, supported by tools such as social cartography, tours of the farms, historical production graphs, activity calendars and the elaboration of formats of frequency of food consumption and the timing of harvests. The results show that most of the farms (with the exception of one) are in conversion to agroecology. This interest has resulted in the strengthening of the four categories considered in the analysis of food autonomy. For this reason, agroecology, ancestral knowledge and food autonomy cannot be separated.Maestrí

Mechanical and Thermal Behavior of Ultem® 9085 Fabricated by Fused-Deposition Modeling

Fused-deposition modeling (FDM) is an additive manufacturing technique which is widely used for the fabrication of polymeric end-use products in addition to the development of prototypes. Nowadays, there is an increasing interest in the scientific and industrial communities for new materials showing high performance, which can be used in a wide range of applications. Ultem 9085 is a thermoplastic material that can be processed by FDM; it recently emerged thanks to such good properties as excellent flame retardancy, low smoke generation, and good mechanical performance. A deep knowledge of this material is therefore necessary to confirm its potential use in different fields. The aim of this paper is the investigation of the mechanical and thermal properties of Ultem 9085. Tensile strength and three-point flexural tests were performed on samples with XY, XZ, and ZX building orientations. Moreover, the influence of dierent ageing treatments performed by varying the maximum reached temperature and relative humidity on the mechanical behavior of Ultem 9085 was then investigated. The thermal and thermo-oxidative behavior of this material was also determined through thermal-gravimetric analyses

Isomorph invariance and thermodynamics of repulsive dense bi-Yukawa one-component plasmas

In numerous realizations of complex plasmas, dust-dust interactions are characterized by two screening lengths and are thus better described by a combination of Yukawa potentials. The present work investigates the static correlations and the thermodynamics of repulsive dense bi-Yukawa fluids based on the fact that such strongly coupled systems exhibit isomorph invariance. The strong virial-potential energy correlations are demonstrated with the aid of molecular dynamics simulations, an accurate analytical expression for the isomorph family of curves is obtained and an empirical expression for the fluid-solid phase-coexistence line is proposed. The isomorph-based empirically modified hypernetted-chain approach, grounded on the ansatz of isomorph invariant bridge functions, is then extended to such systems and the resulting structural properties show an excellent agreement with the results of computer simulations. A simple and accurate closed-form expression is obtained for the excess internal energy of dense bi-Yukawa fluids by capitalizing on the compact parameterization offered by the Rosenfeld-Tarazona decomposition in combination with the Rosenfeld scaling, which opens up the energy route to thermodynamics.Comment: 11 pages, 6 figure