Differences between thin films deposition systems in the production transition metal nitride

The progress in vacuum technology have enabled the development of advanced coatings processes such as plasma assisted systems, which can produce thin films of different composition and optimum properties, that cannot be collected for the same material. The techniques of Pulsed Arc, Ionic Implantation and Sputtering have differences to produce coatings. Currently, AuN films have been grown by different techniques such as ion implantation, Reactive Ion Sputtering and Pulsed Arc, which have differences in the grown of the film. Siller 2002 reported a binding energy of 396.6 eV to N1s narrow spectrum as the first direct observation of a gold nitride. In this work, AuN thin films were grown in a system Plasma-Assisted Physical Vapor Deposition by pulsed arc technique. A N1s spectra was obtained with binding energies of 398.1, which by means of the differences between the techniques of ion implantation, sputtering and pulsed arc is concluded have been assigned to gold nitride species

Reporte preliminar: Entendiendo las preferencias y actitudes al escoger el medio de transporte en estudiantes universitarios

Transportation plays an important role in a society and understanding the travel behavior is crucial in order to provide a framework to planners and policymaker to shift toward more sustainable transportation mode. Capturing this behavior in university students have been the focus of attention in the past years. Developing countries has specific characteristics such rapid in traffic congestion, sprawl urban development, safety concerns and a high degree of informal transportation. This study was done in Lima, capital of Peru, and a survey was performed for freshmen and senior students at the San Ignacio de Loyola University. Factors relevant considered were time to commute, transportation mode awareness, safety and security. The findings clearly show the students’ preferences of the different modes clearly and provide insights regerding of transportation infrastructure needs, and potential possibilities to shift toward more sustainable modes.El transporte juega un papel muy importante en una sociedad y, por lo tanto, comprender el comportamiento de los usuarios es fundamental con el objetivo de proporcionar un marco para los planificadores y formuladores de políticas que busquen motivar a los ciudadanos hacia modos de transporte más sostenibles. Los países en desarrollo tienen características específicas, como una intensa congestión vehicular y una fuerte expansión urbana, problemas de seguridad y un alto grado de informalidad en el transporte. Es así que, en los últimos años, el entendimiento de dicho comportamiento entre los estudiantes universitarios ha sido el foco de atención. En tal sentido, el presente estudio se llevó a cabo en Lima, capital del Perú, para lo cual se realizó una encuesta con estudiantes del primer, segundo, noveno y décimo ciclo de la Universidad San Ignacio de Loyola. En ella se consideraron factores relevantes como tiempo para viajar, conciencia del modo de transporte, protección y seguridad. Los resultados muestran claramente la percepción de los alumnos respecto a los diferentes modos de transporte y proporcionan una visión de las necesidades de infraestructura y las posibilidades potenciales de cambiar hacia medios más sostenibles

Π- Contenedores inteligentes, ¿un packaging factible para integrar la logística hacia adelante y logística inversa en Latinoamérica?

Logistics is a concept that is the subject of much interest due to the strategic impact for businesses. Efficient logistics will not only generate savings and higher returns but will also have a positive impact on the environment. This article focuses on a main component of logistics such as packaging of products and the use of π - Smart Containers proposed by the Physical Internet Initiative is evaluated as an alternative in developing countries. This document describes the benefits of smart containers, but especially it analyzes its main aspects regarding container modularity, technology adoption, and complexity of the logistics network. The expected result is that the integration of forward and reverse logistics is complex but these smart containers could be an interesting possibility to consider in Latin American countries, especially due to the fact that it might allow better resource directionality for infrastructure investment. The findings may be useful in providing insights when the concept of reverse logistics is incorporated into the Physical Internet Initiative.La logística es un concepto que está siendo objeto de mucho interés por su impacto estratégico para las empresas. Una logística eficiente no solo les genera ahorros y mayor rentabilidad, sino que produce un impacto positivo en el ambiente. Este artículo se enfoca en un componente principal dentro de la logística, que es el packaging de los productos (empaque), y también se evalúa como una alternativa el uso de π - contenedores inteligentes propuesto por la Physical Internet Initiative en países en desarrollo. Este documento describe los beneficios de los contenedores inteligentes pero, sobre todo, analiza sus principales aspectos en relación con su modularidad, la adopción tecnológica y la complejidad de la red logística. El resultado esperado es el hecho de que la integración de la logística hacia adelante y la logística inversa es compleja, pero estos contenedores podrían ser una posibilidad interesante para los países latinoamericanos, especialmente porque les permitiría una mejor direccionalidad de recursos en inversión de infraestructura. Los hallazgos podrían ser útiles para proporcionar puntos de vista cuando se incorpora el concepto de logística inversa en la Physical Internet Initiative.

Phase transitions, double-scaling limit, and topological strings

Topological strings on Calabi--Yau manifolds are known to undergo phase transitions at small distances. We study this issue in the case of perturbative topological strings on local Calabi--Yau threefolds given by a bundle over a two-sphere. This theory can be regarded as a q--deformation of Hurwitz theory, and it has a conjectural nonperturbative description in terms of q--deformed 2d Yang--Mills theory. We solve the planar model and find a phase transition at small radius in the universality class of 2d gravity. We give strong evidence that there is a double--scaled theory at the critical point whose all genus free energy is governed by the Painlev\'e I equation. We compare the critical behavior of the perturbative theory to the critical behavior of its nonperturbative description, which belongs to the universality class of 2d supergravity. We also give evidence for a new open/closed duality relating these Calabi--Yau backgrounds to open strings with framing.Comment: 49 pages, 3 eps figures; section added on non-perturbative proposal and 2d gravity; minor typos correcte

Holomorphic anomaly and matrix models

The genus g free energies of matrix models can be promoted to modular invariant, non-holomorphic amplitudes which only depend on the geometry of the classical spectral curve. We show that these non-holomorphic amplitudes satisfy the holomorphic anomaly equations of Bershadsky, Cecotti, Ooguri and Vafa. We derive as well holomorphic anomaly equations for the open string sector. These results provide evidence at all genera for the Dijkgraaf--Vafa conjecture relating matrix models to type B topological strings on certain local Calabi--Yau threefolds.Comment: 23 pages, LaTex, 3 figure

Nonperturbative aspects of ABJM theory

Using the matrix model which calculates the exact free energy of ABJM theory on S^3 we study non-perturbative effects in the large N expansion of this model, i.e., in the genus expansion of type IIA string theory on AdS4xCP^3. We propose a general prescription to extract spacetime instanton actions from general matrix models, in terms of period integrals of the spectral curve, and we use it to determine them explicitly in the ABJM matrix model, as exact functions of the 't Hooft coupling. We confirm numerically that these instantons control the asymptotic growth of the genus expansion. Furthermore, we find that the dominant instanton action at strong coupling determined in this way exactly matches the action of an Euclidean D2-brane instanton wrapping RP^3.Comment: 26 pages, 14 figures. v2: small corrections, final version published in JHE

Nonperturbative effects and nonperturbative definitions in matrix models and topological strings

We develop techniques to compute multi-instanton corrections to the 1/N expansion in matrix models described by orthogonal polynomials. These techniques are based on finding trans-series solutions, i.e. formal solutions with exponentially small corrections, to the recursion relations characterizing the free energy. We illustrate this method in the Hermitian, quartic matrix model, and we provide a detailed description of the instanton corrections in the Gross-Witten-Wadia (GWW) unitary matrix model. Moreover, we use Borel resummation techniques and results from the theory of resurgent functions to relate the formal multi-instanton series to the nonperturbative definition of the matrix model. We study this relation in the case of the GWW model and its double-scaling limit, providing in this way a nice illustration of various mechanisms connecting the resummation of perturbative series to nonperturbative results, like the cancellation of nonperturbative ambiguities. Finally, we argue that trans-series solutions are also relevant in the context of topological string theory. In particular, we point out that in topological string models with both a matrix model and a large N gauge theory description, the nonperturbative, holographic definition involves a sum over the multi-instanton sectors of the matrix modelComment: 50 pages, 12 figures, comments and references added, small correction

The inverse problem for confined aquifer flow: Identification and estimation with extensions

The contributions of this work are twofold. First, a methodology for estimating the elements of parameter matrices in the governing equation of flow in a confined aquifer is developed. The estimation techniques for the distributed‐parameter inverse problem pertain to linear least squares and generalized least squares methods. The linear relationship among the known heads and unknown parameters of the flow equation provides the background for developing criteria for determining the identifiability status of unknown parameters. Under conditions of exact or overidentification it is possible to develop statistically consistent parameter estimators and their asymptotic distributions. The estimation techniques, namely, two‐stage least squares and three stage least squares, are applied to a specific groundwater inverse problem and compared between themselves and with an ordinary least squares estimator. The three‐stage estimator provides the closer approximation to the actual parameter values, but it also shows relatively large standard errors as compared to the ordinary and two‐stage estimators. The estimation techniques provide the parameter matrices required to simulate the unsteady groundwater flow equation. Second, a nonlinear maximum likelihood estimation approach to the inverse problem is presented. The statistical properties of maximum likelihood estimators are derived, and a procedure to construct confidence intervals and do hypothesis testing is given. The relative merits of the linear and maximum likelihood estimators are analyzed. Other topics relevant to the identification and estimation methodologies, i.e., a continuous‐time solution to the flow equation, coping with noise‐corrupted head measurements, and extension of the developed theory to nonlinear cases are also discussed. A simulation study is used to evaluate the methods developed in this study. Copyright 1987 by the American Geophysical Union

On solution of the inverse problem for confined aquifer flow via maximum likelihood

Joint estimation of transmissivity (T) and storativity (S) in a confined aquifer is done via maximum likelihood (ML). The differential equation of groundwater flow is discretized by the finite-element method, leading to equation ψφ{symbol}t+Γxt=ut. Elements of matrices ψ and Γ, as well as estimated covariance matrix of noise term ut, are functions of T and S. By minimizing the negative loglikelihood function corresponding to discretized groundwater flow equation with respect to T and S, ML estimators are obtained. The ML approach is found to yield accurate estimates of T and S (within 9 and 10% of their actual values, respectively) and showed quadratic convergence in Newton's search technique. Prediction of aquifer response, using ML estimators, results in estimated piezometric heads accurate to ±0.5 m from their actual, exact values. Statistical properties of ML estimators are derived and some basic results for statistical inference are given. © 1986 Plenum Publishing Corporation