Diseño de un modelo de vivienda bioclimática y sostenible. Fase II

El presente documento busca retroalimentar la propuesta de vivienda planteada en la primera fase de la investigación, por medio de un experimento en el cual se midieron datos de temperatura y humedad relativa en modelos a escala hechos con tres sistemas constructivos livianos diferentes. De esta forma es posible determinar cuál sistema constructivo es más apto para las distintas condiciones climáticas que se presentan en el país, de acuerdo con las características propias de cada sitio. La investigación se complementa con una profundización de los elementos que deben ser tomados en cuenta en el diseño de una vivienda que satisfaga las necesidades básicas y la aplicación del diseño bioclimático, proponiendo modelos conceptuales que contienen alternativas tecnológicas y se analiza su factibilidad de aplicación. Se presentan, además, un breve análisis de la legislación salvadoreña en cuanto a la construcción de viviendas y aspectos básicos de la vivienda de interés social en el país, planteando un análisis que pretende superar la visión economicista para resaltar la importancia de la participación de las personas para la contextualización de las propuestas y satisfacción de necesidades.La presente investigación fue subvencionada por la Universidad Tecnológica de El Salvador y contó con la colaboración delos estudiantes Madeline Recinos Hidalgo y José Roberto Galeano, de la carrera de Diseño Gráfico; y Víctor Ernesto Castro Martínez, de la carrera de Arquitectura. Las solicitudes de información, separatas y otros documentos relativos al presente estudio pueden hacerse a la dirección postal: calle Arce, 1020, Universidad Tecnológica de El Salvador, Vicerrectoría de Investigación, Dirección de Investigaciones, calle Arce y 17ª.avenida Norte, edificio José Martí, 2ª planta, o al correo electrónico: [email protected] Tecnológica de El Salvado

An architectural framework for heterogeneous networking.

The growth over the last decade in the use of wireless networking devices has been explosive. Soon many devices will have multiple network interfaces, each with very different characteristics. We believe that a framework that encapsulates the key challenges of heterogeneous networking is required. Like a map clearly helps one to plan a journey, a framework is needed to help us move forward in this unexplored area. The approach taken here is similar to the OSImodel in which tightly defined layers are used to specify functionality, allowing a modular approach to the extension of systems and the interchange of their components, whilst providing a model that is more oriented to heterogeneity and mobility

Granular components of cement: Influence of mixture composition

Raw granular materials used in cement manufacturing are limestone grains displaying a broad size distribution, ranging from microns to a couple of inches. They are stored as pyramidal heaps and, although empirical homogenization techniques are used with good results, there are important factors like segregation and grinding conditions that produce mixtures with different poorly controlled size. For this reason, the stability of the heaps strongly depends on these factors and it is important to study the influence of the respective amounts of particles of different sizes on the properties of the mixture. In this work, we report experiments analyzing the relationship between the characteristic angles of equilibrium of the heaps and the geometry, size and chemical composition of the grains. We also look for correlations between the values of the characteristic angles and the relative amounts of grains of different sizes that make up the materials. We demonstrate that the chemical composition is correlated with the geometry of the grains and that their aspect ratio does not influence the critical angles. We also show that the critical angles mostly depend on the relative amount of fine grains in the granular mixture and on the dispersion of the sizes. The results obtained allow one to draw conclusions that may be relevant to the treatment and storage of raw materials in the cement industry.Fil: Vidales, Ana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Ippolito, Irene Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física. Grupo de Medios Porosos; ArgentinaFil: Benegas, Oscar Armando. Universidad Nacional de San Luis; ArgentinaFil: Aguirre, F.. Universidad Nacional de San Luis; ArgentinaFil: Nocera, O. C.. Universidad Nacional de San Luis; ArgentinaFil: Baudino, M. R.. Universidad Nacional de San Luis; Argentin

An attenuation study of body waves in the south‐central region of the Gulf of California, México

Author Posting. © Seismological Society of America, 2014. This article is posted here by permission of Seismological Society of America for personal use, not for redistribution. The definitive version was published in Bulletin of the Seismological Society of America 104 (2014): 2027-2042, doi:10.1785/0120140015.We studied the seismic attenuation of body waves in the south‐central region of the Gulf of California (GoC) with records from the Network of Autonomously Recording Seismographs of Baja California (NARS‐Baja), from the Centro de Investigación Científica y de Educación Superior de Ensenada’s Broadband Seismological Network of the GoC (RESBAN), and from the ocean‐bottom seismographs (OBS) deployed as part of the Sea of Cortez Ocean Bottom Array experiment (SCOOBA). We examine 27 well‐located earthquakes reported in Sumy et al. (2013) that occurred from October 2005 to October 2006 with magnitudes (Mw) between 3.5 and 4.8. We estimated S‐wave site effects by calculating horizontal‐to‐vertical spectral ratios and determined attenuation functions with a nonparametric model by inverting the observed spectral amplitudes of 21 frequencies between 0.13 and 12.59 Hz for the SCOOBA (OBS) stations and 19 frequencies between 0.16 and 7.94 Hz for NARS‐Baja and RESBAN stations. We calculated the geometrical spreading and the attenuation (1/Q) factors for two distance intervals (10–120 and 120–220 km, respectively) for each frequency considered. The estimates of Q obtained with the SCOOBA (OBS) records for the interval 10–120 km indicate that the P waves attenuate more than S waves (QP=34±1.2f 0.82±0.10, QS=59±1.1f 0.90±0.03) for frequencies between 0.6 and 12.6 Hz; whereas for the 120–220 km interval, where ray paths travel deeper, S waves attenuate more than P waves (QP=117±1.3f 0.44±0.19, QS=51±1.2f 1.12±0.11). The estimates of Q obtained using NARS‐Baja and RESBAN records, within 10–120 km, indicate that P waves attenuate more than S waves (QP=69±1.2f 0.87±0.16, QS=176±1.4f 0.61±0.26) at frequencies between 0.3 and 6.3 Hz; whereas at the 120–220 km distance interval S waves attenuate slightly more than P waves (QP=39±1.1f 0.64±0.06, QS=48±1.1f 0.37±0.07) at high frequencies (f>3  Hz). These results, based on a unique OBS dataset, provide an indirect mean to constrain future models of the thermal structure beneath the GoC.The operation of the RESBAN network has been possible thanks to the financial support of the Mexican National Council for Science and Technology (CONACYT; projects CB-2011-01-165401[C0C059], G33102-T, and 59216). The first author benefited from a fellowship provided by CONACYT between August 2011 and August 2013. We also thank the financial support given by the Earth Science Division of Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE) to write this paper.2015-07-0

Effects of Scale-Free Disorder on the Anderson Metal-Insulator Transition

We investigate the three-dimensional Anderson model of localization via a modified transfer-matrix method in the presence of scale-free diagonal disorder characterized by a disorder correlation function $g(r)$ decaying asymptotically as $r^{-\alpha}$. We study the dependence of the localization-length exponent $\nu$ on the correlation-strength exponent $\alpha$. % For fixed disorder $W$, there is a critical $\alpha_{\rm c}$, such that for $\alpha < \alpha_{\rm c}$, $\nu=2/\alpha$ and for $\alpha > \alpha_{\rm c}$, $\nu$ remains that of the uncorrelated system in accordance with the extended Harris criterion. At the band center, $\nu$ is independent of $\alpha$ but equal to that of the uncorrelated system. The physical mechanisms leading to this different behavior are discussed.Comment: submitted to Phys. Rev. Let

Tollmien-Schlichting waves over forward-facing steps: An experimental and numerical study

This work presents an experimental and numerical investigation jointly conducted by TU Delft and DLR on Tollmien-Schlichting (TS) waves interaction with a Forward-Facing Step (FFS). Experiments are conducted at the TU Delft low turbulence anechoic wind tunnel on an unswept flat plate model. Single-frequency disturbances are introduced using controlled acoustic excitation. The temporal response of the flow in the vicinity of the step is measured using Hot-Wire Anemometry (HWA). In addition, the global effect of the step on laminar-turbulent transition is captured using Infrared Thermography (IR). Two-dimensional (2-D) Direct Numerical Simulations (DNS) performed at DLR provide detailed information at the step. Experimental and DNS results in clean and step case conditions present very good agreement. Both methods predict large distortion of the TS waves downstream of the step, where DNS results present different growth trends between velocity components of the TS waves. Furthermore, negative and positive regions of the production term are observed to correlate with streamwise positions where the disturbances appear tilted in and against the mean shear, respectively. These findings point towards the presence of different growth mechanisms triggered by the step which could modify the level of amplification of disturbances far downstream

DNS of the interaction of crossflow instabilities with forward-facing steps

Previous studies on the interaction between stationary crossflow (CF) vortices and a forward-facing step (FFS) have shown a significant influence on the laminar-turbulent transition (e.g. [1, 2]). In a recent experimental investigation, Rius-Vidales & Kotsonis [3] found that the effect of the step height on the transition location is non-monotonic. An unprecedented transition delay (w.r.t to the case without FFS) occurs when the incoming stationary CF vortices interact with a shallow FFS. Instead, the interaction with a higher FFS leads to an upstream advancement of the transition front location. The present work aims to numerically reproduce the experimental setup in [3] through direct numerical simulation (DNS). The current investigation’s final goal is to understand further the flow physics behind the observed behaviour in the experiments

Uptake of gases in bundles of carbon nanotubes

Model calculations are presented which predict whether or not an arbitrary gas experiences significant absorption within carbon nanotubes and/or bundles of nanotubes. The potentials used in these calculations assume a conventional form, based on a sum of two-body interactions with individual carbon atoms; the latter employ energy and distance parameters which are derived from empirical combining rules. The results confirm intuitive expectation that small atoms and molecules are absorbed within both the interstitial channels and the tubes, while large atoms and molecules are absorbed almost exclusively within the tubes.Comment: 9 pages, 12 figures, submitted to PRB Newer version (8MAR2K). There was an error in the old one (23JAN2K). Please download thi

The Role of Power-Law Correlated Disorder in the Anderson Metal-Insulator Transition

We study the influence of scale-free correlated disorder on the metal-insulator transition in the Anderson model of localization. We use standard transfer matrix calculations and perform finite-size scaling of the largest inverse Lyapunov exponent to obtain the localization length for respective 3D tight-binding systems. The density of states is obtained from the full spectrum of eigenenergies of the Anderson Hamiltonian. We discuss the phase diagram of the metal-insulator transition and the influence of the correlated disorder on the critical exponents.Comment: 6 pages, 3 figure