Tras los “desaparecidos” de la Guerra Civil. Una etnografía multisituada y multitemporal

El desarrollo del proyecto de investigación Lloros vueltos puños. El conflicto de los ‘desaparecidos’ y vencidos de la guerra civil española, centrado en el movimiento social por la recuperación de la memoria histórica, ha precisado de una combinación de metodologías que atendiera la irrupción y variedad de contextos y materiales que iban surgiendo. La particularidad de enfrentar un sufrimiento social sucedido en un pasado distante suponía enfrentar comunidades dispersas, espacios marginales de muerte -las fosas-, la configuración de agrupaciones y asociaciones de víctimas…, todo lo cual ha exigido, entre otras, la adopción de metodologías multisituacionales. Inevitablemente, la suma de voces y generaciones conllevó el entremezclamiento de contextos históricos y culturas políticas, lo que requirió adoptar, también, análisis multitemporales. Este trabajo recorre los principales retos metodológicos que caracterizaron el seguimiento del tema de la memoria histórica durante más de una década. El resultado es una reflexión sobre los beneficios o perjuicios de determinadas tareas investigativas en contextos inestables o en rápida transformación

A bestia buena, vara y espuelas: Historia cultural del maltrato estudiantil

The abuse and mistreatment, or hazing, of first-year students, is as old as universities themselves. These violent and humiliating behaviors are today legitimated by their longevity, presented as traditions. This article reviews the historic roots of hazing as constituted by the confluence of institutional elements–tied to the guild roots of medieval universities –and factors derived from long-standing European violent cultural practices. Using an interdisciplinary methodological perspective, the text analyzes historical information, literary works, and ethnological materials, paying special attention to the ritual and festive manifestations of popular culture, and especially, of youth, as a period culturally perceived and defined as semi-savage and prone to violence.El abuso y maltrato a los novatos es tan antiguo como las propias universidades. Aún hoy se sufren estos comportamientos violentos y humillantes bajo la disculpa de tratarse de una tradición. Este artículo revisa los orígenes históricos de tales maltratos a partir de la confluencia de elementos institucionales –ligados al origen gremial de las universidades medievales–, junto con otros provenientes de las viejas violencias culturales europeas. A partir de una perspectiva metodológica interdisciplinar, el trabajo analiza informaciones históricas, obras literarias y materiales etnológicos con particular atención a las manifestaciones rituales y festivas propias de la cultura popular y, especialmente, de la juventud como edad cultural percibida semisalvaje y pronta a la violencia

STEM Tools for Semiconductor Characterization: Beyond High-Resolution Imaging

The smart engineering of novel semiconductor devices relies on the development of optimized functional materials suitable for the design of improved systems with advanced capabilities aside from better efficiencies. Thereby, the characterization of these materials at the highest level attainable is crucial for leading a proper understanding of their working principle. Due to the striking effect of atomic features on the behavior of semiconductor quantum- and nanostructures, scanning transmission electron microscopy (STEM) tools have been broadly employed for their characterization. Indeed, STEM provides a manifold characterization tool achieving insights on, not only the atomic structure and chemical composition of the analyzed materials, but also probing internal electric fields, plasmonic oscillations, light emission, band gap determination, electric field measurements, and many other properties. The emergence of new detectors and novel instrumental designs allowing the simultaneous collection of several signals render the perfect playground for the development of highly customized experiments specifically designed for the required analyses. This paper presents some of the most useful STEM techniques and several strategies and methodologies applied to address the specific analysis on semiconductors. STEM imaging, spectroscopies, 4D-STEM (in particular DPC), and in situ STEM are summarized, showing their potential use for the characterization of semiconductor nanostructured materials through recent reported studies.This work has been co-financed by the 2014-2020 ERDF Operational Programme and by the Department of Economy, Knowledge, Business and the University of the Regional Government of Andalusia. (FEDER-UCA18-106586). Co-funding from Junta de Andalucia (Research group INNANOMAT, ref. TEP-946) and UE is also acknowledged

Development of carbon fiber acrylonitrile styrene acrylate composite for large format additive manufacturing

The increasing interest of Large Format Additive Manufacturing (LFAM) technologies in various industrial sectors mainly lies on the attainable production of pieces reaching several cubic meters. These new technologies require the development of optimized materials with two-folded capabilities, able to satisfy functional in-service requirements but also showing a proper printability. Acrylonitrile Styrene Acrylate (ASA) is among the most interesting thermoplastic materials to be implemented in a LFAM device due to its excellent wettability and mechanical properties. This research focuses on the development and characterization of ASA and carbon fiber (CF) ASA composites suitable for LFAM. The rheological, thermal and mechanical properties of neat ASA and ASA containing 20 wt% CF are addressed. The results evidence the higher performance of the CF loaded composite compared to the raw ASA polymer (i.e., the 20 wt% CF composite shows a 350% increase in flexural Young's Modulus and a 500% increment in thermal conductivity compared with neat ASA). Additionally, both materials were successfully printed along perpendicular directions (X and Z), showing the maximum tensile strain for the composite printed along the X orientation as was expected. The results of the flexural tests are comparable or slightly higher than those of injected parts. Finally, the fracture surface was analysed, identifying different types of porosity

Structural Characterization of Al0.37In0.63N/AlN/p-Si (111) Heterojunctions Grown by RF Sputtering for Solar Cell Applications

Compact Al0.37In0.63N layers were grown by radiofrequency sputtering on bare and 15 nm-thick AlN-buffered Si (111) substrates. The crystalline quality of the AlInN layers was studied by high-resolution X-ray diffraction measurements and transmission electron microscopy. Both techniques show an improvement of the structural properties when the AlInN layer is grown on a 15 nm-thick AlN buffer. The layer grown on bare silicon exhibits a thin amorphous interfacial layer between the substrate and the AlInN, which is not present in the layer grown on the AlN buffer layer. A reduction of the density of defects is also observed in the layer grown on the AlN buffer

Printable Graphene Oxide Nanocomposites as Versatile Platforms for Immobilization of Functional Biomolecules

A series of novel nanocomposites containing graphene oxide (GO) suitable for stereolithography is presented. Different loads of GO are tested, identifying that these materials can be printed with concentrations up to 2.5 wt% GO, presenting improved mechanical properties for concentrations below 1.0 wt% GO. In this range, the nanocomposites exhibit higher strength and toughness when compared to the pristine resin. Microscopic analyses of the material demonstrate that this can be correlated with the good compatibility of GO with the resin, which favors its homogeneous dispersion in the form of flexible nanoplates. After manufacturing, the availability of GO to participate in surface modification reactions with chitosan (CHI) and an alkaline phosphatase (ALP) is evaluated. CHI and ALP are well-known to act as biological cues in biorecognition processes, evidencing that these nanocomposites are suitable as platforms for selective immobilization of functional biomolecules.This work was funded by the Ministry of Science, Innovation and Universities (TEC2017-86102-C2-2-R), the 2014-2020 ERDF Operational Programme and the Department of Economy, Knowledge, Business and University of the Regional Government of Andalusia (FEDER-UCA18-106586). Co-funding from UE and the research group INNANOMAT (ref. TEP-946) is also acknowledged. A.S.d.L. and M.d.l.M. acknowledge Ministry of Science, Innovation and Universities for their Juan de la Cierva Incorporacion postdoctoral fellowships (IJC2019-041128-I, IJCI-2017-31507). SEM and TEM measurements were carried out at the DME-SC-ICyT-ELECMI-UCA

Plasmonic Characterization of 3D Printable Metal-Polymer Nanocomposites

Plasmonic polymer nanocomposites (i.e., polymer matrices containing plasmonic nanostructures) are appealing candidates for the development of manifold technological devices relying on light-matter interactions, provided that they have inherent properties and processing capabilities. The smart development of plasmonic nanocomposites requires in-depth optical analyses proving the material performance, along with correlative studies guiding the synthesis of tailored materials. Importantly, plasmon resonances emerging from metal nanoparticles affect the macroscopic optical response of the nanocomposite, leading to far- and near-field perturbations useful to address the optical activity of the material. We analyze the plasmonic behavior of two nanocomposites suitable for 3D printing, based on acrylic resin matrices loaded with Au or Ag nanoparticles. We compare experimental and computed UV-vis macroscopic spectra (far-field) with single-particle electron energy loss spectroscopy (EELS) analyses (near-field). We extended the calculations of Au and Ag plasmon-related resonances over different environments and nanoparticle sizes. Discrepancies between UV-vis and EELS are dependent on the interplay between the metal considered, the surrounding media, and the size of the nanoparticles. The study allows comparing in detail the plasmonic performance of Au- and Ag-polymer nanocomposites, whose plasmonic response is better addressed, accounting for their intended applications (i.e., whether they rely on far- or near-field interactions)

Self-Assembly of CsPbBr3Perovskites in Micropatterned Polymeric Surfaces: Toward Luminescent Materials with Self-Cleaning Properties

In this work, we present a series of porous, honeycomb-patterned polymer films containing CsPbBr3 perovskite nanocrystals as light emitters prepared by the breath figure approach. Microscopy analysis of the topography and composition of the material evidence that the CsPbBr3 nanocrystals are homogeneously distributed within the polymer matrix but preferably confined inside the pores due to the fabrication process. The optical properties of the CsPbBr3 nanocrystals remain unaltered after the film formation, proving that they are stable inside the polystyrene matrix, which protects them from degradation by environmental factors. Moreover, these surfaces present highly hydrophobic behavior due to their high porosity and defined micropatterning, which is in agreement with the Cassie-Baxter model. This is evidenced by performing a proof-of-concept coating on top of 3D-printed LED lenses, conferring the material with self-cleaning properties, while the CsPbBr3 nanocrystals embedded inside the polymeric matrix maintain their luminescent behavior.This work was funded by the Ministry of Science, Innovation and Universities (project TEC2017-86102-C2-2-R) and Junta de Andalucía (Research group INNANOMAT, ref. TEP-946) and co-financed by the 2014-2020 ERDF Operational Programme and by the Department of Economy, Knowledge, Business and University of the Regional Government of Andalusia (ref: FEDER-UCA18-106586). Co-funding from UE is also acknowledged. A.S.d.L. acknowledges the Ministry of Science, Innovation and Universities for his Juan de la Cierva Incorporación postdoctoral fellowship (IJC2019-041128-I). R.A. also acknowledges the support of the Spanish MINECO through projects: Retos-Colaboración 2016 Project Safetag (no. RTC-2016-5197-2) and Retos de la Sociedad Project Nirvana (no. PID2020-119628RB-C31) by MCIN/AEI/10.13039/ 501100011033 and the “Agencia Valenciana de la Innovació” for the Valorització 2018 Project Hidronio (no. INNVAL10/ 18/032) and Valorització 2021 Project CATIOX (no. INNVA1/2021/56). R.A. also thanks the Spanish MINECO for their Ramón y Cajal Fellowship (no. RYC-2015-18349). SEM and TEM measurements were carried out at the DME-SCICyT- ELECMI-UCA

Caracterización estructural, composicional y plasmónica de nanopartículas de galio mediante haces de electrones.

Resumen del proyecto de líneas prioritarias "Caracterización estructural, composicional y plasmónica de nanopartículas de galio mediante haces de electrones" del IMEYMAT

Additive Manufacturing of Gold Nanostructures Using Nonlinear Photoreduction under Controlled Ionic Diffusion

Multiphoton photoreduction of photosensitive metallic precursors via direct laser writing (DLW) is a promising technique for the synthesis of metallic structures onto solid substrates at the sub-micron scale. DLW triggered by a two photon absorption process is done using a femtosecond NIR laser (lambda = 780 nm), tetrachloroauric acid (HAuCl4) as a gold precursor, and isinglass as a natural hydrogel matrix. The presence of a polymeric, transparent matrix avoids unwanted diffusive processes acting as a network for the metallic nanoparticles. After the writing process, a bath in deionized water removes the gold precursor ions and eliminates the polymer matrix. Different aspects underlying the growth of the gold nanostructures (AuNSs) are here investigated to achieve full control on the size and density of the AuNSs. Writing parameters (laser power, exposure time, and scanning speed) are optimized to control the patterns and the AuNSs size. The influence of a second bath containing Au3+ to further control the size and density of the AuNSs is also investigated, observing that these AuNSs are composed of individual gold nanoparticles (AuNPs) that grow individually. A fine-tuning of these parameters leads to an important improvement of the created structures' quality, with a fine control on size and density of AuNSs.W.D.C. and M.G. acknowledge the support of the CNR Facility Beyond-Nano-Polo di Cosenza. W.D.C. acknowledges MIUR (Ministero dell'Istruzione, dell'Universita e della Ricerca-Italy) for her industrial PhD grant (PONa3_00362). This work was also funded by Ministry of Science, Innovation and Universities (project TEC2017-86102-C2-2-R) and Junta de Andalucia (Research group INNANOMAT, ref. TEP-946). Co-funding from UE is also acknowledged. A.S.d.L. and M.d.l.M. acknowledge Ministry of Science, Innovation and Universities for their Juan de la Cierva Incorporacion postdoctoral fellowships (IJC2019-041128-I, IJCI-2017-31507). SEM and TEM measurements were carried out at the DME-SC-ICyT-ELECMI-UCA. Documen