Transverse free vibration of resonant nanoplate mass sensors: Identification of an attached point mass

In this paper we analyse for the first time the bending vibration of a nanoplate with an attached mass using the strain gradient elasticity theory for homogeneous Lame material, under Kirchhoff-Love's kinematical assumptions. The exact eigenvalues of the nanoplate vibrating with an attached mass are obtained for a general case, and an approximate closed form expression is provided if the intensity of the mass is small with respect to the total mass of the nanoplate. The inverse problem of identifying a point mass attached on a simply supported rectangular nanoplate from a selected minimal set of resonant frequency data is also considered. We show that if the point mass is small, then the position of the point mass and mass size can be determined by means of closed form expressions in terms of the changes induced by the point mass on the first three resonant frequencies. The identification procedure has been tested on an extended series of numerical simulations, varying the scale parameter of the nanoplate's material and the position and size of the point mass.The authors from University Carlos III of Madrid wish to acknowledge the Ministerio de Economía y Competitividad de España for the financial support, under grants number DPI2014-57989-P and DPI2013-45406-P. A. Morassi gratefully acknowledges the financial support of the National Research Project PRIN 2015TTJN95 Identification and monitoring of complex structural systems.Publicad

Sorprendente, colorido, suave, raro: recursos líticos y preferencias culturales en la arquitectura, escultura y artefactos portables del monumento tipo tholos de Palacio III (Sevilla, España)

The investigation of the Iberian megalithic phenomenon has only recently begun to benefit from the expansion of the technical and scientific potential of modern archaeology. There are still very few Iberian megaliths for which high resolution scientific research has been carried out, providing detailed data on their design, uses and biographies. This paper presents the results of the multi-disciplinary study of the Palacio III tholos, part of a larger megalithic complex located in Almadén de la Plata (Seville). This study is based on a wide-spectrum methodology that integrates geoarchaeology, techno-morphological and functional analysis of portable material culture and graphic analysis, all combined within a meticulously contextual perspective. The results provide a wealth of data on how, through a series of carefully constructed cultural choices, this monument represents a true place of encounter between the locally available geological resources and other resources that were only accessible through contact with neighbouring communities. Whether in its raw state, finely carved in the form of engraved and painted sculptures or transformed into artefacts of high technical and personal value, the materiality of the stone in the Palacio III tholos acquires multiple cultural dimensions that only a modern scientific approach is able to reconstruct.Solo recientemente la investigación del fenómeno megalítico ibérico ha comenzado a beneficiarse de la ampliación del potencial técnico y científico de la arqueología moderna. Todavía son muy pocos los megalitos ibéricos para los que se han realizado investigaciones científicas de alta resolución, capaces de aportar datos detallados sobre su diseño, usos y biografías. En este trabajo se presentan los resultados del estudio del tholos del complejo megalítico de Palacio III (Almadén de la Plata, Sevilla), abordado mediante una metodología multidisciplinar que integra la geoarqueología, el estudio tecnomorfológico y funcional de la cultura material portable y el análisis gráfico, dentro de una meticulosa valoración contextual. Los resultados aportan datos muy novedosos respecto a cómo, a través de una serie de elecciones culturales cuidadosamente construidas, este monumento representa un verdadero lugar de encuentro entre los recursos geológicos localmente disponibles y los recursos accesibles mediante contacto con otras comunidades. Bien en su forma bruta, bien labrada en forma de esculturas grabadas y pintadas o transformada en artefactos de alto valor técnico y personal, la materialidad de la piedra adquiere en Palacio III múltiples dimensiones culturales que solo a través de la moderna investigación científica es posible reconstruir.This study has been funded by the project of “Nature, Society and Monumentality: High Resolution Archaeological Investigations on the Megalithic Landscape of Antequera” (HAR2013-45149-P) (2014-2017), sponsored within the National R&D Plan of the Ministry of Economy and Competitiveness (Spanish Government)

A numerical study of the effect of nozzle diameter on diesel combustion ignition and flame stabilization

This is the author's version of a work that was accepted for publication in International Journal of Engine Research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published as https://doi.org/10.1177/1468087419864203.[EN] The role of nozzle diameter on diesel combustion is studied by performing computational fluid dynamics calculations of Spray A and Spray D from the Engine Combustion Network. These are well-characterized single-hole sprays in a quiescent environment chamber with thermodynamic conditions representative of modern diesel engines. First, the inert spray evolution is described with the inclusion of the concept of mixing trajectories and local residence time into the analysis. Such concepts enable the quantification of the mixing rate, showing that it decreases with the increase in nozzle diameter. In a second step, the reacting spray evolution is studied focusing on the local heat release rate distribution during the auto-ignition sequence and the quasi-steady state. The capability of a well-mixed-based and a flamelet-based combustion model to predict diesel combustion is also assessed. On one hand, results show that turbulence-chemistry interaction has a profound effect on the description of the reacting spray evolution. On the other hand, the mixing rate, characterized in terms of the local residence time, drives the main changes introduced by the increase of the nozzle diameter when comparing Spray A and Spray D.The author(s) disclosed receipt of the following financial support for the research, authorship and/or publication of this article: The work was partially funded by the Government of Spain through the CHEST Project (TRA2017-89139-C2-1-R) and by Universitat Politecnica de Valencia through the Programa de Ayudas de Investigaciony Desarrollo (PAID-01-16).Desantes Fernández, JM.; García-Oliver, JM.; Novella Rosa, R.; Pachano-Prieto, LM. (2020). A numerical study of the effect of nozzle diameter on diesel combustion ignition and flame stabilization. International Journal of Engine Research. 21(1):101-121. https://doi.org/10.1177/1468087419864203S101121211Pickett, L. M., & Siebers, D. L. (2002). An investigation of diesel soot formation processes using micro-orifices. Proceedings of the Combustion Institute, 29(1), 655-662. doi:10.1016/s1540-7489(02)80084-0Pickett, L. M., & Siebers, D. L. (2005). Orifice Diameter Effects on Diesel Fuel Jet Flame Structure. Journal of Engineering for Gas Turbines and Power, 127(1), 187-196. doi:10.1115/1.1760525Du, C., Andersson, S., & Andersson, M. (2018). Two-dimensional measurements of soot in a turbulent diffusion diesel flame: the effects of injection pressure, nozzle orifice diameter, and gas density. Combustion Science and Technology, 190(9), 1659-1688. doi:10.1080/00102202.2018.1461850Ishibashi, R., & Tsuru, D. (2016). An optical investigation of combustion process of a direct high-pressure injection of natural gas. Journal of Marine Science and Technology, 22(3), 447-458. doi:10.1007/s00773-016-0422-xPang, K. M., Jangi, M., Bai, X.-S., Schramm, J., & Walther, J. H. (2017). Effects of Nozzle Diameter on Diesel Spray Flames: A numerical study using an Eulerian Stochastic Field Method. Energy Procedia, 142, 1028-1033. doi:10.1016/j.egypro.2017.12.350Pickett, L. M., Manin, J., Genzale, C. L., Siebers, D. L., Musculus, M. P. B., & Idicheria, C. A. (2011). Relationship Between Diesel Fuel Spray Vapor Penetration/Dispersion and Local Fuel Mixture Fraction. SAE International Journal of Engines, 4(1), 764-799. doi:10.4271/2011-01-0686García-Oliver, J. M., Malbec, L.-M., Toda, H. B., & Bruneaux, G. (2017). A study on the interaction between local flow and flame structure for mixing-controlled Diesel sprays. Combustion and Flame, 179, 157-171. doi:10.1016/j.combustflame.2017.01.023Dahms, R. N., Paczko, G. A., Skeen, S. A., & Pickett, L. M. (2017). Understanding the ignition mechanism of high-pressure spray flames. Proceedings of the Combustion Institute, 36(2), 2615-2623. doi:10.1016/j.proci.2016.08.023Gimeno, J., Martí-Aldaraví, P., Carreres, M., & Peraza, J. E. (2018). Effect of the nozzle holder on injected fuel temperature for experimental test rigs and its influence on diesel sprays. International Journal of Engine Research, 19(3), 374-389. doi:10.1177/1468087417751531Matusik, K. E., Duke, D. J., Kastengren, A. L., Sovis, N., Swantek, A. B., & Powell, C. F. (2017). High-resolution X-ray tomography of Engine Combustion Network diesel injectors. International Journal of Engine Research, 19(9), 963-976. doi:10.1177/1468087417736985Pandurangi, S. S., Bolla, M., Wright, Y. M., Boulouchos, K., Skeen, S. A., Manin, J., & Pickett, L. M. (2016). Onset and progression of soot in high-pressure n-dodecane sprays under diesel engine conditions. International Journal of Engine Research, 18(5-6), 436-452. doi:10.1177/1468087416661041Aubagnac-Karkar, D., Michel, J.-B., Colin, O., & Darabiha, N. (2017). Combustion and soot modelling of a high-pressure and high-temperature Dodecane spray. International Journal of Engine Research, 19(4), 434-448. doi:10.1177/1468087417714351Ihme, M., Ma, P. C., & Bravo, L. (2018). Large eddy simulations of diesel-fuel injection and auto-ignition at transcritical conditions. International Journal of Engine Research, 20(1), 58-68. doi:10.1177/1468087418819546Yue, Z., & Reitz, R. D. (2017). An equilibrium phase spray model for high-pressure fuel injection and engine combustion simulations. International Journal of Engine Research, 20(2), 203-215. doi:10.1177/1468087417744144Bhattacharjee, S., & Haworth, D. C. (2013). Simulations of transient n-heptane and n-dodecane spray flames under engine-relevant conditions using a transported PDF method. Combustion and Flame, 160(10), 2083-2102. doi:10.1016/j.combustflame.2013.05.003Pei, Y., Hawkes, E. R., & Kook, S. (2013). Transported probability density function modelling of the vapour phase of an n-heptane jet at diesel engine conditions. Proceedings of the Combustion Institute, 34(2), 3039-3047. doi:10.1016/j.proci.2012.07.033Pang, K. M., Jangi, M., Bai, X.-S., Schramm, J., & Walther, J. H. (2018). Modelling of diesel spray flames under engine-like conditions using an accelerated Eulerian Stochastic Field method. Combustion and Flame, 193, 363-383. doi:10.1016/j.combustflame.2018.03.030D’Errico, G., Lucchini, T., Contino, F., Jangi, M., & Bai, X.-S. (2014). Comparison of well-mixed and multiple representative interactive flamelet approaches for diesel spray combustion modelling. Combustion Theory and Modelling, 18(1), 65-88. doi:10.1080/13647830.2013.860238Kösters, A., Karlsson, A., Oevermann, M., D’Errico, G., & Lucchini, T. (2015). RANS predictions of turbulent diffusion flames: comparison of a reactor and a flamelet combustion model to the well stirred approach. Combustion Theory and Modelling, 19(1), 81-106. doi:10.1080/13647830.2014.982342Lucchini, T., D’Errico, G., Onorati, A., Frassoldati, A., Stagni, A., & Hardy, G. (2017). Modeling Non-Premixed Combustion Using Tabulated Kinetics and Different Fame Structure Assumptions. SAE International Journal of Engines, 10(2), 593-607. doi:10.4271/2017-01-0556Pal, P., Keum, S., & Im, H. G. (2015). Assessment of flamelet versus multi-zone combustion modeling approaches for stratified-charge compression ignition engines. International Journal of Engine Research, 17(3), 280-290. doi:10.1177/1468087415571006Pope, S. B. (1978). An explanation of the turbulent round-jet/plane-jet anomaly. AIAA Journal, 16(3), 279-281. doi:10.2514/3.7521Novella, R., García, A., Pastor, J. M., & Domenech, V. (2011). The role of detailed chemical kinetics on CFD diesel spray ignition and combustion modelling. Mathematical and Computer Modelling, 54(7-8), 1706-1719. doi:10.1016/j.mcm.2010.12.048CONVERGE manual. Madison, WI: Convergent Science, 2016.Yao, T., Pei, Y., Zhong, B.-J., Som, S., Lu, T., & Luo, K. H. (2017). A compact skeletal mechanism for n-dodecane with optimized semi-global low-temperature chemistry for diesel engine simulations. Fuel, 191, 339-349. doi:10.1016/j.fuel.2016.11.083Perez E. Application of a flamelet-based combustion model to diesel-like reacting sprays. Unpublished PhD Thesis, Universitat Politècnica de València, Valencia, 2019.Peters, N. (2000). Turbulent Combustion. doi:10.1017/cbo9780511612701Naud, B., Novella, R., Pastor, J. M., & Winklinger, J. F. (2015). RANS modelling of a lifted H2/N2 flame using an unsteady flamelet progress variable approach with presumed PDF. Combustion and Flame, 162(4), 893-906. doi:10.1016/j.combustflame.2014.09.014Payri, R., García-Oliver, J. M., Xuan, T., & Bardi, M. (2015). A study on diesel spray tip penetration and radial expansion under reacting conditions. 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A conceptual model of the flame stabilization mechanisms for a lifted Diesel-type flame based on direct numerical simulation and experiments. Combustion and Flame, 201, 65-77. doi:10.1016/j.combustflame.2018.12.00

Influence of key operational parameters on biohydrogen production from fruit and vegetable waste via lactate-driven dark fermentation

Producción CientíficaThis study aims at investigating the influence of operational parameters on biohydrogen production from fruit-vegetable waste (FVW) via lactate-driven dark fermentation. Mesophilic batch fermentations were conducted at different pH (5.5, 6.0, 6.5, 7.0, and non-controlled), total solids (TS) contents (5, 7, and 9%) and initial cell biomass concentrations (18, 180, and 1800 mg VSS/L). Higher hydrogen yields and rates were attained with more neutral pH values and low TS concentrations, whereas higher biomass densities enabled higher production rates and avoided wide variations in hydrogen production. A marked lactate accumulation (still at neutral pH) in the fermentation broth was closely associated with hydrogen inhibition. In contrast, enhanced hydrogen productions matched with much lower lactate accumulations (even it was negligible in some fermentations) along with the acetate and butyrate co-production but not with carbohydrates removal. At pH 7, 5% TS, and 1800 mg VSS/L, 49.5 NmL-H2/g VSfed and 976.4 NmL-H2/L-h were attained.Junta de Castilla y Leon - Fondo Europeo de Desarrollo Regional (grants CLU 2017-09, CL-EI-2021-07 and UIC 315

Plexcitonic quantum light emission from nanoparticle-on-mirror cavities

We investigate the quantum-optical properties of the light emitted by a nanoparticle-on-mirror cavity filled with a single quantum emitter. Inspired by recent experiments, we model a dark-field setup and explore the photon statistics of the scattered light under grazing laser illumination. Exploiting analytical solutions to Maxwell's equations, we quantize the nanophotonic cavity fields and describe the formation of plasmon-exciton polaritons (or plexcitons) in the system. This way, we reveal that the rich plasmonic spectrum of the nanocavity offers unexplored mechanisms for nonclassical light generation that are more efficient than the resonant interaction between the emitter natural transition and the brightest optical mode. Specifically, we find three different sample configurations in which strongly antibunched light is produced. Finally, we illustrate the power of our approach by showing that the introduction of a second emitter in the platform can enhance photon correlations furthe

ANTIBIOTICOTERAPIA EN EL AMBIENTE HOSPITALARIO COSTARRICENSE: EL CASO HOSPITAL CLINICA BIBLICA ENERO – JUNIO 2012

Appropriate use of antibiotics is a key factor needed in order to increase patients’ survival, limiting adverse events and the development of bacterial resistance. This paper analyzes the antibiotic pharmacotherapy used at Hospital Clinica Biblica, for patients that have used antibiotics for at least 48 hours and had at least one of the following conditions: osteomyelitis, lower respiratory tract infection, cellulitis, sepsis, invasive endocarditis, meningitis, intra-abdominal infections, urinary tract infections and infections associated with intravascular catheter. The selection of these conditions was made considering local epidemiology. According to the data collected, in 93% of cases (97 patients) antibiotics were appropriately prescribed, 75% of cases did not follow the international recommendations when two or more antibiotics are combined, and only in 30% of cases the bacteria involved in the infectious process was isolated. It can be concluded that the selection of antibiotic therapy should be based on data that validate the local sensitivity. Consulting a clinical pharmacist and/or infectious  disease specialist may prevent errors related to the inadequate use of this class of drugs at the Hospital.El uso apropiado de antibióticos es un factor fundamental para incrementar la  supervivencia de los pacientes, limitar efectos adversos y la resistencia bacteriana. El presente trabajo analiza la farmacoterapia antibiótica utilizada en pacientes internados del Hospital Clínica Bíblica, San José, Costa Rica que recibieron tratamiento al menos durante 48 horas, y cuyo diagnóstico fuera una de las siguientes patologías: osteomielitis, infecciones de tracto respiratorio inferior, celulitis, sepsis, endocarditis invasiva, meningitis, infecciones intraabdominales, infecciones de tracto urinario e infecciones intravasculares asociadas a catéter. La selección de estas patologías responde a la epidemiología y a las necesidades planteadas localmente. Según los datos recolectados, en el 93% de las ocasiones (97 casos) los antibióticos se prescriben adecuadamente.  Cuando se utilizaron tratamientos antibióticos combinados, en el 75% de las ocasiones no se siguieron las recomendaciones de referencia, y sólo  en un 30% de los casos se conoce  la bacteria involucrada en el proceso infeccioso. Se puede concluir que la selección de la antibióticoterapia debe estar fundamentada con datos que validen la sensibilidad local. El aporte que puede incorporar la interconsulta con un infectólogo y el farmacéutico clínico puede prevenir los errores relacionados con el uso de este grupo de fármacos en el Hospital

Enhancement of biogas production rate from bioplastics by alkaline pretreatment

Producción CientíficaThe effect of alkali-based pretreatment on the methanization of bioplastics was investigated. The tested bioplastics included PHB [poly(3-hydroxybutyrate)], PHBH [poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)], PHBV [poly(3-hydroxybutyrate-co-3-hydroxyvalerate], PLA (polylactic acid), and a PLA/PCL [poly(caprolactone)] 80/20 blend. Prior to methanization tests, the powdered polymers (500–1000 μm) at a concentration of 50 g/L were subjected to alkaline pretreatment using NaOH 1 M for PLA and PLA/PCL, and NaOH 2 M for PHB-based materials. Following 7 days of pretreatment, the amount of solubilized carbon for PLA and its blend accounted for 92–98% of the total initial carbon, while lower carbon recoveries were recorded for most PHB-based materials (80–93%), as revealed by dissolved total organic carbon analysis. The pretreated bioplastics were then tested for biogas production by means of mesophilic biochemical methane potential tests. Compared to unpretreated PHBs, methanization rates of pretreated PHBs were accelerated by a factor of 2.7 to 9.1 with comparable (430 NmL CH4/g material feed) or slightly lower (15% in the case of PHBH) methane yields, despite featuring a 1.4–2.3 times longer lag phases. Both materials, PLA and the PLA/PCL blend, were only extensively digested when pretreated, yielding about 360–380 NmL CH4 per gram of material fed. Unpretreated PLA-based materials showed nearly zero methanization under the timeframe and experimental conditions tested. Overall, the results suggested that alkaline pretreatment can help to enhance the methanization kinetics of bioplastics.Ministerio de Ciencia e Innovación - AEI and European Union NextGenerationEU/PRTR (RYC2021‐034559‐I)Junta de Castilla y León - EU-FEDER (CLU 2017-09, CL-EI-2021-07 y UIC 315

Cysteine String Protein- Prevents Activity-Dependent Degeneration in GABAergic Synapses

The continuous release of neurotransmitter could be seen to place a persistent burden on presynaptic proteins, one that could compromise nerve terminal function. This supposition and the molecular mechanisms that might protect highly active synapses merit investigation. In hippocampal cultures from knock-out mice lacking the presynaptic cochaperone cysteine string protein-_ (CSP-_),weobserve progressive degeneration of highly active synaptotagmin 2 (Syt2)-expressing GABAergic synapses, but surprisingly not of glutamatergic terminals. In CSP-_ knock-out mice, synaptic degeneration of basket cell terminals occurs in vivo in the presence of normal glutamatergic synapses onto dentate gyrus granule cells. Consistent with this, in hippocampal cultures from these mice, the frequency of miniature IPSCs, caused by spontaneous GABA release, progressively declines, whereas the frequency of miniature excitatory AMPA receptormediated currents (mEPSCs), caused by spontaneous release of glutamate, is normal. However, the mEPSC amplitude progressively decreases. Remarkably, long-term block of glutamatergic transmission in cultures lacking CSP-_ substantially rescues Syt2-expressing GABAergic synapses from neurodegeneration. These findings demonstrate that elevated neural activity increases synapse vulnerability and that CSP-_ is essential to maintain presynaptic function under a physiologically high-activity regimen