Stirling Engine class

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.The problem of a lack of science and engineering opportunities for youth has been identified. While other programs and attempted solutions exist, a novel approach involving creating self-contained project classes, called modules, and trading them between institutions is proposed. This idea intends to make these lacking opportunities available while overcoming some of the current problems opposing this availability namely insufficient resources and staff. While limited time and resources prevents the complete testing of the idea, the development of a single module to the point before developing a trading system is implemented. The project chosen is the construction and operation of the Stirling Engine using a design borrowed from MIT course 2.670. The module is tested with 15 4th to 7th grade home-schooled students in Los Angeles, Ca. Observations and participant feedback are gathered. Changes including the shortening of lectures, simplification of the project, and addition of testing are proposed. The information gathered from the test suggests that with a trading system in place, these modules can expose students to science and engineering and generate excitement for the fields.by Patrick R. Barragán.S.B

Social segregation of indigenous migrants in Mexico: An overview from Monterrey

In Mexico, rural to urban migration is a clearly noticeable phenomenon. During the last few years, there has been spontaneous growth in the migration of indigenous people towards the northern cities of Mexico, especially to Monterrey, in search of employment. Once the migrants arrive in this metropolis, they face difficulties adjusting and adapting to the city environment because of hidden discrimination. The main argument and hypothesis of this paper is that indigenous people isolate themselves and segregate themselves socially due to fear of (cultural and racial) discrimination and violence. For this study, data were obtained from fieldwork carried out during 2009 and 2010 in Monterrey, Mexico, where we interviewed 350 indigenous people that had moved there from different parts of the country

Articulando las actividades de conjeturar y probar de los matemáticos profesionales desde la teoría de Peirce

“La formulación de conjeturas y el desarrollo de pruebas son dos aspectos fundamentales del trabajo de un matemático profesional” (Alibert y Thomas, 1991, p. 215). La investigación que estamos llevando a cabo pretende proponer un modelo, desde la educación matemática, que describa y explique cómo los matemáticos profesionales desarrollan las actividades de conjeturar y probar. Concretamente, y debido al carácter sociocultural de la investigación en matemáticas, los participantes considerados en este trabajo son investigadores en matemáticas que tienen al menos una publicación en “JCR science edition”

An efficient drive, sensing, and actuation system using PZT stack actuator cells

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 81-82).The PZT cellular actuator developed in the MIT d'Arbeloff Laboratory utilizes small-strain, high-force PZT stack actuators in a mechanical flexure system to produce a larger-strain, lower-force actuator useful in robotic systems. Many functionalities for these cellular actuators are developed which can have great impact on robotic systems and actuation itself. After initial exploration into other possible circuitry, a circuit is designed to recovery unused energy for the PZT cells. The circuit design is formed around a proposed method of distributed actuation using PZT cells which imposes that different PZT cells will be activated during different periods such that the charge from some cells can be transferred to others. If the application allows actuation which can conform to this criteria, the developed circuit can be used which, without optimization, can save ~41% of the energy used to drive the actuators with a theoretical upper limit on energy efficiency of 100%. A dynamic system consisting of multiple PZT actuators driving a linear gear is analyzed and simulated which can achieve a no load speed 2.4 m/s with minimal actuators. Then, the two-way transforming properties of PZT stack actuators are utilized to allow dual sensing and actuation. This method uses an inactive PZT cell as a sensor. With no additional sensors, a pendulum system driven by antagonistic groups of PZT cells is shown to find its own resonance with no system model. These functionalities of charge recovery, distributed actuation, and dual sensing and actuation set the PZT cellular actuator as an important contribution to robotic actuation and begin to illuminate the possible impacts of the concept. The design and analysis described reveals many possibilities for future applications and developments using the PZT cellular actuator in the fields of actuation and robotics.by Patrick R. BarragánS.M

Lo poético burlesco como recurso teatral en «No hay burlas con el amor»

Lo poético burlesco fue un recurso que dramaturgos como Calderón usaron para renovar los desgastados mecanismos de las comedias. En este sentido, No hay burlas con el amor es una obra paradigmática, pues Calderón, además de crear la comicidad mediante la inversión de fórmulas teatrales, se valió de algunos recursos de la poesía burlesca, que, en el plano de la representación, evidenciaban que la obra era un artificio y movían a risa al espectador. El objetivo de este artículo es, precisamente, mostrar cómo funcionaba este procedimiento mediante el diálogo que se entabla entre el texto dramático y el texto espectacular de dicha obra.Burlesque poetry was a resource that playwrights like Calderon used to renew worn mechanisms of comedies. In this sense, No hay burlas con el amor is a paradigmatic work, since Calderon, apart from creating humor by inverting dramatic formulas, used some resources of burlesque poetry, which, in terms of performance, showed that the work was an artifice and that it provoked laughter within the audience. The aim of this article is, precisely, to show how this process worked through the dialogue that is established between the dramatic text and the spectacular text of the work

Functional-bandwidth kernel for Support Vector Machine with Functional Data:An alternating optimization algorithm

Functional Data Analysis (FDA) is devoted to the study of data which are functions. Support Vector Ma- chine (SVM) is a benchmark tool for classification, in particular, of functional data. SVM is frequently used with a kernel (e.g.: Gaussian) which involves a scalar bandwidth parameter. In this paper, we pro- pose to use kernels with functional bandwidths. In this way, accuracy may be improved, and the time intervals critical for classification are identified. Tuning the functional parameters of the new kernel is a challenging task expressed as a continuous optimization problem, solved by means of a heuristic. Our experiments with benchmark data sets show the advantages of using functional parameters and the ef- fectiveness of our approach

Ecuaciones de resistencia al flujo para ríos de montaña

Three models of flow resistance (a Keulegan-type logarithmic law and two models developed for large-scale roughness conditions: the full logarithmic law and a model based on an inflectional velocity profile) were calibrated, validated and compared using an extensive database (N = 1,533) from rivers and flumes, representative of a wide hydraulic and geomorphologic range in the field of gravel-bed and mountain channels. It is preferable to apply the model based on an inflectional velocity profile in the relative submergence (y/d90) interval between 0.5 and 15, while the full logarithmic law is preferable for values below 0.5. For high relative submergence, above 15, either the logarithmic law or the full logarithmic law can be applied. The models fitted to the coarser percentiles are preferable to those fitted to the median diameter, owing to the higher explanatory power achieved by setting a model, the smaller difference in the goodness-of-fit between the different models and the lower influence of the origin of the data (river or flume).Se han calibrado, validado y comparado tres modelos de resistencia al flujo (una ley logarítmica tipo Keulegan y dos modelos desarrollados para condiciones de alta rugosidad: la ley logarítmica completa y un modelo basado en un perfil de velocidad inflexional) empleando para ello una extensa base de datos (N = 1,533) de río y de laboratorio, representativa de un amplio intervalo hidráulico y geomorfológico en el ámbito de cauces de grava y de montaña. El modelo basado en un perfil de velocidad inflexional es preferible para su aplicación en el intervalo de sumersión relativa (y/d90) comprendido entre 0,5 y 15, mientras que la ley logarítmica completa es preferible para valores inferiores a 0,5. Para sumersión relativa alta, por encima de 15, es posible aplicar indistintamente la ley logarítmica y la ley logarítmica completa. Son preferibles los modelos ajustados con los percentiles más gruesos que los ajustados con el diámetro mediano, debido a: la mayor capacidad explicativa alcanzada fijado un modelo, la menor diferencia en la bondad de ajuste entre los diferentes modelos y la menor influencia del origen de los datos (río o laboratorio)

Isotropic and Anisotropic Bouncing Cosmologies in Palatini Gravity

We study isotropic and anisotropic (Bianchi I) cosmologies in Palatini $f(R)$ and $f(R,R_{\mu\nu}R^{\mu\nu})$ theories of gravity and consider the existence of non-singular bouncing solutions in the early universe. We find that all $f(R)$ models with isotropic bouncing solutions develop shear singularities in the anisotropic case. On the contrary, the simple quadratic model $R+a R^2/R_P+R_{\mu\nu}R^{\mu\nu}/R_P$ exhibits regular bouncing solutions in both isotropic and anisotropic cases for a wide range of equations of state, including dust (for $a<0$) and radiation (for arbitrary $a$). It thus represents a purely gravitational solution to the big bang singularity and anisotropy problems of general relativity without the need for exotic ($w>1$) sources of matter/energy.Comment: 25 pages, 7 figure

Improving the accuracy of RF alternate test using multi-VDD conditions: application to envelope-based test of LNAs

Trabajo presentado al "20 Asina Test Symposium" celebrado en Nueva Delhi (India) del 20 al 23 de Noviembre del 2011.-- Reprinted from (relevant publication info). This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of the products or services of CSIC Spanish National Research Council, Digital.CSIC. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.This work demonstrates that multi-VDD conditions may be used to improve the accuracy of machine learning mod- els, significantly decreasing the prediction error. The proposed technique has been successfully applied to a previous alternate test strategy for LNAs based on response envelope detection. A prototype has been developed to show its feasibility. The prototype consists of a low-power 2.4GHz LNA and a simple envelope detector, integrated in a 90nm CMOS technology. Post- layout simulation results are provided to verify the functionality of the approach. Copyright © 2011 IEEE.This work has been partially funded by a CSIC JAE-Doc contract (cofinanced by FSE), a Spanish MAE-AECID grant and projects: SR2 - Short Range Radio (Catrene European project 2A105SR2 and Avanza I+D Spanish project TSI-020400-2010-55, cofinanced with FEDER program), Auto-calibración y auto-test en circuitos analógicos, mixtos y de radio frecuencia (Andalusian Government project P09-TIC-5386, cofinanced with FEDER program), and Catrene project TOETS (CT 302).Peer reviewe

Sur, cuarentena y después

A partir de este dispositivo ponemos en marcha el proyecto editorial de la cátedra Taller Complementario de Grabado y Arte Impreso: SE IMPRIME. Esta primera publicación responde a la convocatoria del proyecto PIBA, investigación propiciada por la Facultad de Artes de la UNLP. La difusión de este contenido se efectuará a través de dos formatos: digital y en soporte papel. A través de este proyecto daremos cuerpo a una multiplicidad de acciones y procesos abordados en las cursadas, que incluyen el tiempo y conceptos transitados y hemos puesto en juego: estrategias de abordaje creativo y pedagógico, decisiones tomadas, construcciones colectivas, componentes afectivos, los vínculos comunitarios y en este momento de aislamiento, la apertura a nuevas redes de difusión.Facultad de Arte