Nuevos materiales compuestos Si/carbono grafitizado como electrodos negativos de alta energía para baterías de litio-ión

II Encuentro sobre nanociencia y nanotecnología de investigadores y tecnólogos de la Universidad de Córdoba. NANOUC

Laser Shock Microforming of Thin Metal Sheets

Continuous and long-pulse lasers have been used for the forming of metal sheets in macroscopic mechanical applications. However, for the manufacturing of micro-electromechanical systems (MEMS), the applicability of such type of lasers is limited by the long-relaxation-time of the thermal fields responsible for the forming phenomena. As a consequence of such slow relaxation, the final sheet deformation state is attained only after a certain time, what makes the generated internal residual stress fields more dependent on ambient conditions and might make difficult the subsequent assembly process from the point of view of residual stresses due to adjustment. The use of ns laser pulses provides a suitable parameter matching for the laser forming of an important range of sheet components used in MEMS that, preserving the short interaction time scale required for the predominantly mechanic (shock) induction of deformation residual stresses, allows for the successful processing of components in a medium range of miniaturization, particularly important according to its frequent use in such systems. In the present paper, a discussion is presented on the physics of laser shock microforming and the influence of the different effects on the net bending angle. The experimental setup used for the experiments, sample fabrication and experimental results of influence of number of laser pulses on the net bending angle are also presented

Simple and Sustainable Preparation of Nonactivated Porous Carbon from Brewing Waste for High-Performance Lithium–Sulfur Batteries

The development of renewable energy sources requires the parallel development of sustainable energy storage systems because of its noncontinuous production. Even the most-used battery on the planet, the lithium-ion battery, is reaching its technological limit. In light of this, lithium–sulfur batteries have emerged as one of the most promising technologies to address this problem. The use of biomass to produce cathodes for these batteries addresses not only the aforementioned problem, but it also reduces the carbon footprint and gives added value to something normally considered waste. Here, the production, by simple and nonactivating pyrolysis, of a carbon material using the abundant “after-boiling waste” derived from beer brewing is reported. After adding a high sulfur loading (70 %) to this biowaste-derived carbon by the “melt diffusion” method, the sulfur–carbon composite is used as an effective cathode in Li–S batteries. The cathode shows excellent performance, reaching high capacity values with long-term cyclability at high current—847 mAh g−1 at 1 C, 586 mAh g−1 at 2 C, and even 498 mAh g−1 at 5 C after 400 cycles—drastically reducing capacity loss to values approaching 0.01 % per cycle. This work demonstrates the possibility of obtaining low-cost, highly sustainable cathodic materials for the design of advanced energy storage systems

Integrating Visual and Energy Criteria for Optimal Window Design in Temperate Climates

Building codes and certifications require maximal building performance in different aspects. However, focusing on achieving a single purpose can prevent obtaining additional ones. This work aims to help building designers balance energy and visual performance design criteria. The difficulty to achieve many goals resides in high degrees of complexity when many building features must be considered in an infinite number of possible design solutions. Multi-objective optimization techniques start to be applied in building science, but different appropiate assessment criteria applied to a single problem can lead to diverse valid solutions. A brief review was made of commonly used energy consumption and visual comfort and performance criteria. The study was made through whole-building computer simulations of a standardized test room. This provided a solution space with "compromise sizes" satisfying both energy and visual aspect objectives. However, unprotected windows cannot meet all these criteria. This makes the provision of sun-protecting elements necessary. A selection procedure based on design needs is detailed

Morphologic and morphometric study of the musculus obliquus dorsalis of the dog

In the present investigation, the dorsal oblique muscle of the right ocular globe was removed from six adult dogs weighing 40-50 kg and analyzed by light microscopy. Muscle samples were taken from the central portion of the muscle belly, subsequently ultrafrozen, cut and stained with m-ATPase at pH 4.6. Fibers were classified as type I or type II according to their reaction to the m-ATPase and detailed morphologic and morphometric studies were made. The muscles showed two clearly distinct layers, a central layer and a peripheral layer, mainly composed of type II fibers. The fibers in the central layer were larger in size than those in the peripheral layer. The peculiar stratigraphy of the dorsal oblique muscle should be taken into account when performing analyses of this muscle and investigating the significance of the fiber types it contains.En el presente trabajo se han extraído, de los globos oculares derechos, de seis perros adultos de 40-50 kilogramos de peso, los músculos oblicuos dorsales y analizados con microscopia de luz. Las muestras musculares para su análisis se tomaron de la porción central del vientre muscular y fueron ultracongeladas, cortadas y teñidas por la técnica de m-ATPasa a pH 4,6. Las fibras se clasificaron en tipo I y tipo II en virtud a su reacción frente a la m-ATPasa, realizándose un detallado estudio morfológico y morfométrico. Los músculos presentaron dos estratos netamente diferenciados, uno central y otro periférico, compuestos mayoritariamente por fibras tipo II. Las fibras del estrato central presentaron un mayor tamaño que las correspondientes del estrato periférico. La peculiar estratigrafía del músculo oblicuo dorsal debería tenerse en consideración al analizar este músculo e investigar el significado de los tipos fibrilares que contien

Discriminación de bosques de Araucaria araucana en el Parque Nacional Conguillío, centro-sur de Chile, mediante datos Landsat TM

Martin, JS (San Martin, Jose). Univ Talca, Inst Biol Vegetal & Biotecnol, Talca, ChileAraucaria forests (Araucaria araucana) have a tremendous ecological relevance; however, the information concerning their spatial distribution is still insufficient. They have only been classified according to small management scales, using satellite photos and images processed through conventional methods. The present study had as its objective to discriminate and characterize types of A. araucana forests in the Conguillio National Park, located in the Southern-Center Chile, through data derived from the Landsat-5 TM satellite and geographic information systems. The normalized difference vegetation index (NDVI) was satisfactorily related with variables corresponding to crown coverage and the diameter at breast height; thus, these index values were incorporated to the classification process. Using the digital elevation model and the NDVI, the effect provoked by the shadow was minimized. Seven types of forests, between dense and semi-dense-open, were discriminated in accordance with the accompanying species. The global reliability of the classification was 83.8 %. The greatest reliability for the producer was for the medium crown density forest of A. araucana - N. dombeyi (B1) (87.5 %); and for the consumer, for the high crown density forests of A. araucana - N. dombeyi (B1) and also for those of medium density (B2) (93 %). It is concluded that incorporating NDVI values and data derived from the digital elevation model to the satellite classification process, it is possible to discriminate araucaria forests with satisfactory reliability in areas of rough relief, which is very useful information for the management of these forestry ecosystems

Search strategies for pair production of heavy Higgs bosons decaying invisibly at the LHC

The search for heavy Higgs bosons at the LHC represents an intense experimental program, carried out by the ATLAS and CMS collaborations, which includes the hunt for invisible Higgs decays and dark matter candidates. No significant deviations from the SM backgrounds have been observed in any of these searches, imposing significant constraints on the parameter space of different new physics models with an extended Higgs sector. Here we discuss an alternative search strategy for heavy Higgs bosons decaying invisibly at the LHC, focusing on the pair production of a heavy scalar H together with a pseudoscalar A, through the production mode qq¯→Z⁎→HA. We identify as the most promising signal the final state made up of 4b+ET miss, coming from the heavy scalar decay mode H→hh→bb¯bb¯ with h being the discovered SM-like Higgs boson with mh=125GeV, together with the invisible channel of the pseudoscalar. We work within the context of simplified MSSM scenarios that contain quite heavy sfermions of most types with O(10)TeV masses, while the stops are heavy enough to reproduce the 125 GeV mass for the lightest SM-like Higgs boson. By contrast, the gauginos/higgsinos and the heavy MSSM Higgs bosons have masses near the EW scale. Our search strategies, for a LHC center-of-mass energy of s=14TeV, allow us to obtain statistical significances of the signal over the SM backgrounds with values up to ∼1.6σ and ∼3σ for total integrated luminosities of 300fb−1 and 1000fb−1, respectively.Fil: Arganda, E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Diaz-Cruz, J.L.. Benemérita Universidad Autónoma de Puebla; MéxicoFil: Mileo, N.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Morales, R.A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Szynkman, A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentin