3D magnetic configuration of the Halpha filament and X-ray sigmoid in NOAA AR 8151

We investigate the structure and relationship of an H $\alpha$ filament and an X-ray sigmoid observed in active region NOAA 8151. We first examine the presence of such structures in the reconstructed 3D coronal magnetic field obtained from the non-constant- $\alpha$ force-free field hypothesis using a photospheric vector magnetogram (IVM, Mees Solar Observatory). This method allows us to identify several flux systems: a filament (height 30 Mm, aligned with the polarity inversion line (PIL), magnetic field strength at the apex 49 G, number of turns 0.5-0.6), a sigmoid (height 45 Mm, aligned with the PIL, magnetic field strength at the apex 56 G, number of turns 0.5-0.6) and a highly twisted flux tube (height 60 Mm, magnetic field strength at the apex 36 G, number of turns 1.1-1.2). By searching for magnetic dips in the configuration, we identify a filament structure which is in good agreement with the H $\alpha$ observations. We find that both filament and sigmoidal structures can be described by a long twisted flux tube with a number of turns less than 1 which means that these structures are stable against kinking. The filament and the sigmoid have similar absolute values of $\alpha$ and Jz in the photosphere. However, the electric current density is positive in the filament and negative in the sigmoid: the filament is right-handed whereas the sigmoid is left-handed. This fact can explain the discrepancies between the handedness of magnetic clouds (twisted flux tubes ejected from the Sun) and the handedness of their solar progenitors (twisted flux bundles in the low corona). The mechanism of eruption in AR 8151 is more likely not related to the development of instability in the filament and/or the sigmoid but is associated with the existence of the highly twisted flux tube (~1.1-1.2 turns)

Aplicación de la investigación cualitativa, como un estilo de investigación con alma crítica, flexible y creativa, para generar impactos en la comunidad

Durante mucho tiempo se ha conocido y realizado solamente investigaciones cuantitativas. Pero en el siglo XIX surgió en EEUU la investigación cualitativa desde la perspectiva sociológica. Con los años, a medida que fue desarrollándose el método, se ha trabajado en la aplicación de mejoras. En el presente ensayo se realizó un informe descriptivo de la investigación cualitativa, exponiendo los aspectos más importantes de este enfoque investigativo, en base a una vasta y selectiva bibliografía referente al tema; con el objeto de presentar los elementos conceptuales y metodológicos básicos que serán aplicados en el momento de optar por una investigación de corte cualitativo, siendo esta una forma peculiar de estudiar el impacto que genera la universidad en la realidad social, y desde una perspectiva holística e “in situ”

Friedel oscillations responsible for stacking fault of adatoms: The case of Mg(0001) and Be(0001)

We perform a first-principles study of Mg adatom and adislands on the Mg(0001) surface, and Be adatom on Be(0001), to obtain further insights into the previously reported energetic preference of the fcc faulty stacking of Mg monomers on Mg(0001). We first provide a viewpoint on how Friedel oscillations influence ionic relaxation on these surfaces. Our three-dimensional charge-density analysis demonstrates that Friedel oscillations have maxima which are more spatially localized than what one-dimensional average density or two-dimensional cross sectional plots could possibly inform: The well-known charge-density enhancement around the topmost surface layer of Mg(0001) is strongly localized at its fcc hollow sites. The charge accumulation at this site explains the energetically preferred stacking fault of the Mg monomer, dimer and trimer. Yet, larger islands prefer the normal hcp stacking. Surprisingly, the mechanism by which the fcc site becomes energetically more favorable is not that of enhancing the surface-adatom bonds but rather those between surface atoms. To confirm our conclusions, we analyze the stacking of Be adatom on Be(0001) - a surface also largely influenced by Friedel oscillations. We find, in fact, a much stronger effect: The charge enhancement at the fcc site is even larger and, consequently, the stacking-fault energy favoring the fcc site is quite large, 44 meV.Comment: Submitted to Physical Review

Parque-mirador Senderos del Vergel

Trabajo de gradoLa idea de crear un proyecto de renovación urbana para la población. El proyecto Parque mirador “Senderos del Vergel”, busca minimizar el impacto y concepto nocivo de la población de Bella Vista Baja y Barrios Aledaños hacia la quebrada Bella Vista, mediante la activación de un sistema de parques saludables para impulsar la apropiación de la población y el flujo peatonal.INTRODUCCIÓN. 1. MARCO JURÍDICO. 2. CONTEXTO. 3. ÁMBITO PERCEPCIÓN. 4. REFERENTES. 5. DIAGNOSTICO. 6. DETERMINANTES. 7. DESARROLLO. 8. PROYECTO. BIBLIOGRAFÍA. ANEXOSPregradoArquitect

Za\u27a Demi-Fine Jewelry: Cultural representation through the use of wearable crafts

Za\u27a is an e-commerce demi-fine jewelry brand that gives its wearer the ability to explore, connect and give back to indigenous Latin American cultures. Za\u27a pieces are made with 14k gold, sterling silver, vermeil (solid gold electroplated silver), and semi-precious gemstones while incorporating traditional craftsmanship; incorporating elements such as woodcarving, embroidery, and painting. What makes Za\u27a\u27s products unique is that they are designed and fabricated in conjunction with the communities, ensuring fair and ethical practices. This close collaboration turns the pieces into a cultural bridge of communication, an exchange of ideas, and an appreciation between consumers and the indigenous communities. The key attributes that give Za\u27a a competitive advantage are its strong community-centered focus built around ethical practices, product transparency, and its give-back initiative

DESIGN & DEVELOPMENT OF PLANAR SOLID OXIDE FUEL CELL STACK

In the present work, planar anode-supported Solid Oxide Fuel Cell short-stacks have been designed, assembled, tested and characterized. The design of the stacks and its components (frame, housing, interconnect, compressive and bonded seals) required a great attention to the materials properties (i.e. thermal expansion coefficient compatibility, durability, strength and oxidation resistance, conductivity and so on), as well as to the fluid-dynamic analysis focused on flow field and gas distribution. Then, a careful analysis was done based on a multidisciplinary approach to select the stack components materials, geometries, and dimensions; in order to assure a high performing stack at elevated temperatures with cost reduction of materials, parts manufacturing and assembly procedure. The materials selected were: Crofer®22APU for the interconnect and the frame; AISI 316L for bolts and housing; Thermiculite® 866 for the compressive seal placed between the frame and the interconnect plate; Flexible Mica Paper for the compressive seal positioned between the interconnect endplate and the housing; SiO2-CaO-Al2O3-Na2O glass-ceramic sealant for the bonded seal to join the frame with the cell. On the other hand, the stack assembly was focused on the implementation of innovative and simple procedures, which allowed power capacity scale-up in accordance to power requirements. In this work, two different stack configurations were produced: with one cell (for initial testing of the materials and fluid-dynamic selected solutions) and with three cells. It must be mentioned that all developed stacks in this research were assembled with commercial cells "ASC3" from H.C. Starck. Also, calculations at ambient temperature and 800°C were done in the stack compression system to determine the proper tightening torque to be applied: this value was 50N. Although this calculation took into consideration the loss of tightening torque at high temperatures, some marks were found in housing and micas during the stack inspection after disassembly. These marks are a clear indicator of gas leakage. Additionally, a study was carried out related to the effect of the protective Mn1.5Co1.5O4 coating deposited on interconnect surface to prevent the cathode Cr poisoning. This experiment was executed in the stack of one cell configuration. No voltage degradation was observed during the galvanostatic experiment of 360 h at 800°