Melting of Lennard-Jones rare gas clusters doped with a single impurity atom

Single impurity effect on the melting process of magic number Lennard-Jones, rare gas, clusters of up to 309 atoms is studied on the basis of Parallel Tempering Monte Carlo simulations in the canonical ensemble. A decrease on the melting temperature range is prevalent, although such effect is dependent on the size of the impurity atom relative to the cluster size. Additionally, the difference between the atomic sizes of the impurity and the main component of the cluster should be considered. We demonstrate that solid-solid transitions due to migrations of the impurity become apparent and are clearly differentiated from the melting up to cluster sizes of 147 atoms

Análisis psicométrico de las escalas Ryff (versión española) en una muestra de adolescentes chilenos

Cuadra, IG (reprint author), Univ Talca, Talca, Chile.The present work examines the psychometric properties of the psychological well-being scale proposed by Ryff (Spanish version) in Chilean adolescents. The sample consisted of 335 adolescents from the city of Talca, Chile, who completed the scale of psychological well-being in its version of 39 items validated for Spanish population. Reliability and construct validity analysis was conducted, resulting in a good reliability value for the entire scale, although by dimensions it took values between acceptable and bad. Regarding construct validity, the model proposed by Ryff showed the best theoretical fit compared with alternatives. Both psychometric properties were improved by reducing the amount of items in the scale according to statistical criteria

Interpolated potential energy surface and classical dynamics for H₃⁺+HD and H₃⁺+D₂

A potential energy surface for H₅⁺ has been constructed by a modified Shepard interpolation on a sparse set of data points, using second order Möller–Plesset perturbation theory. An improved version of the surface was also obtained by substituting the energy values at the data points with values evaluated using a coupled cluster treatment (with single and double excitations, and perturbative treatment of triple excitations). Classical simulations for the collisions between H₃⁺+HD and H₃⁺+D2 were carried out in order to calculate the total integral cross sections and rate coefficients for these systems. There is good agreement with earlier experimental data for rate coefficients at temperatures between 80 and 300 K, but the predicted rate coefficient for the reaction of H₃⁺+HD at 10 K deviates from the most recent experimental measurement, suggesting that quantum rather than classical reactiondynamics are necessary

Molecular potential energy surfaces by interpolation: Strategies for faster convergence

A method for interpolating molecular potential energy surfaces introduced [Ischtwan and Collins, J. Chem. Phys. 100, 8080 (1994)] and developed as an iterative scheme has been improved by different criteria for the selection of the data points. Refinements in the selection procedure are based on the variance of the interpolation and the direct exploration of the interpolation error, and produce more accurate surfaces than the previously established scheme for the same number of data points

Diseño y Optimización del tamaño de grano triturado para alimentación avícola para criaderos y suministro de balanceado/Design and Optimization of crushed grain size for poultry feed for hatcheries and supply of balanced

En la investigación se diseñó, modeló y mejoró un molino de martillo económico y accesible aplicando métodos lógicos deductivos, la máquina provee un tamaño de grano ideal, que sirve como alimentación directa para aves, o también se puede utilizar como un componente para balanceado en la producción avícola, acorde a los requerimientos de las distintas pymes ya sea para consumo cárnico, producción de huevos, entre otros. Por esta razón es necesario definir distintos parámetros como el tamaño adecuado del tamiz teniendo una variedad desde los 2mm hasta los 5 mm, cuchillas, selección adecuada del motor dependiendo de la cantidad de horas por día, para esto se realizó un análisis mecánico y dinámico de los distintos elementos de la máquina mediante simulación en el software Solidworks free students, luego de tener el dimensionamiento óptimo bajo parámetros ingenieriles de cada una de las partes de la máquina, se realizó una cotización de los materiales bajo consideración económica en el que fue necesario realizar una correcta selección de los mismo elementos basados en catálogos nacionales para que la maquina sea rentable y accesible a los micro productores así como a los mayoristas, una vez considerado todo el procedimiento se construyó la máquina con un costo final de 355,39 dólares americanos, siendo esta de fácil desmontaje, mantenimiento y aplicación para la sociedad, el cual permite la reducción de costos, tiempos de producción y aumenta la eficiencia en la obtención grano triturado para el consumo el sector avícola. In the research an economical and accessible hammer mill was designed, modeled and improved by applying deductive logical methods, the machine provides an ideal grain size, which serves as direct feed for birds, or it can also be used as a component for balanced in the poultry production, according to the requirements of the different SMEs, whether for meat consumption, egg production, among others. For this reason, it is necessary to define different parameters such as the appropriate size of the sieve having a variety from 2mm to 5 mm, blades, suitable engine selection depending on the number of hours per day, for this a mechanical and dynamic analysis of the different elements of the machine by means of simulation in the software Solidworks free students, after having the optimal dimensioning under engineering parameters of each one of the parts of the machine, a quotation of the materials was made under economic consideration in which it was necessary to carry out a correct selection of the same elements based on national catalogs so that the machine is profitable and accessible to the micro producers as well as to the wholesalers. Once the entire procedure was considered, the machine was built with a final cost of US $ 355.39. being this easy to disassembly, maintenance and application for society, which allows the reduction of costs, production times and increases the efficiency in obtaining crushed grain for consumption in the poultry sector. Palabras clave: diseño, producción avícola, grano, balanceado, molino, grano triturado. Keywords: design, poultry production, grain, balanced, mill, crushed grain

Customer Service During the Health Emergency in the La Condamine Shopping Centre

Sales management involves the establishment of strategic objectives, development and control of the action plan, and planning and management of the necessary resources to increase revenue. Customer service is a fundamental marketing tool and has a direct impact on sales. It is responsible for establishing places of contact with customers and for using channels while establishing relationships with them before, during, and after the sale of a good or service [6]. The purpose of this work was to analyze and predetermine how the quality of customer service influenced sales during the health emergency at the La Condamine Shopping Center in the city of Riobamba. The study sample included 200 merchants. The results show a need for improvement in customer service by the sales representative in order to increase their sales. Keywords: customer care, service, sales, consumers, pandemic. Resumen La gestión en ventas involucra el establecimiento de objetivos estratégicos, el desarrollo y el control del plan de acción, la planificación y la gestión de los recursos necesarios que permita incrementar los ingresos. La atención al cliente es una herramienta fundamental del marketing y consecuentemente tiene una incidencia directa sobre las ventas, es la encargada de establecer lugares de contacto con los clientes, utilizando canales al tiempo de establecer relaciones con ellos, antes durante y después de la venta de un bien o un servicio. [6]. El propósito del presente trabajo fue analizar y predeterminar como el servicio de atención al cliente influyo en las ventas durante la emergencia sanitaria en el Centro Comercial La Condamine de la ciudad de Riobamba La muestra con quienes se realizó el estudio corresponden a 200 comerciantes. Los resultados muestran que los vendedores deben mejorar la atención al cliente para poder aumentar las ventas en sus negocios. Palabras Clave: atención al cliente, servicio, ventas, consumidores, pandemia

Interpolated potential energy surfaces and dynamics for atom exchange between H and H⁺₃, and D and H⁺₃

Two ab initio interpolated potential energy surfaces have been constructed to study the dynamics of atomic hydrogen/deuterium exchange in collisions of H(3)(+) with H (D). One of the surfaces is based on energy calculations using quadratic configuration interaction with single and double excitations. The second includes a perturbative treatment of the triple excitations and an additive correction for basis set deficiency. Results from classical dynamics simulation of the exchange reaction on these surfaces are presented and discussed

When do generalized entropies apply? How phase space volume determines entropy

We show how the dependence of phase space volume $\Omega(N)$ of a classical system on its size $N$ uniquely determines its extensive entropy. We give a concise criterion when this entropy is not of Boltzmann-Gibbs type but has to assume a {\em generalized} (non-additive) form. We show that generalized entropies can only exist when the dynamically (statistically) relevant fraction of degrees of freedom in the system vanishes in the thermodynamic limit. These are systems where the bulk of the degrees of freedom is frozen and is practically statistically inactive. Systems governed by generalized entropies are therefore systems whose phase space volume effectively collapses to a lower-dimensional 'surface'. We explicitly illustrate the situation for binomial processes and argue that generalized entropies could be relevant for self organized critical systems such as sand piles, for spin systems which form meta-structures such as vortices, domains, instantons, etc., and for problems associated with anomalous diffusion.Comment: 5 pages, 2 figure