30 research outputs found

    On the sub-micron aerosol size distribution in a coastal-rural site at El Arenosillo Station (SW – Spain)

    Get PDF
    This study focuses on the analysis of the sub-micron aerosol characteristics at El Arenosillo Station, a rural and coastal environment in South-western Spain between 1 August 2004 and 31 July 2006 (594 days). The mean total concentration (<i>N</i><sub>T</sub>) was 8660 cm<sup>−3</sup> and the mean concentrations in the nucleation (<i>N</i><sub>NUC</sub>), Aitken (<i>N</i><sub>AIT</sub>) and accumulation (<i>N</i><sub>ACC</sub>) particle size ranges were 2830 cm<sup>−3</sup>, 4110 cm<sup>−3</sup> and 1720 cm<sup>−3</sup>, respectively. Median size distribution was characterised by a single-modal fit, with a geometric diameter, median number concentration and geometric standard deviation of 60 nm, 5390 cm<sup>−3</sup> and 2.31, respectively. Characterisation of primary emissions, secondary particle formation, changes to meteorology and long-term transport has been necessary to understand the seasonal and annual variability of the total and modal particle concentration. Number concentrations exhibited a diurnal pattern with maximum concentrations around noon. This was governed by the concentrations of the nucleation and Aitken modes during the warm seasons and only by the nucleation mode during the cold seasons. Similar monthly mean total concentrations were observed throughout the year due to a clear inverse variation between the monthly mean <i>N</i><sub>NUC</sub> and <i>N</i><sub>ACC</sub>. It was related to the impact of desert dust and continental air masses on the monthly mean particle levels. These air masses were associated with high values of <i>N</i><sub>ACC</sub> which suppressed the new particle formation (decreasing <i>N</i><sub>NUC</sub>). Each day was classified according to a land breeze flow or a synoptic pattern influence. The median size distribution for desert dust and continental aerosol was dominated by the Aitken and accumulation modes, and marine air masses were dominated by the nucleation and Aitken modes. Particles moved offshore due to the land breeze and had an impact on the particle burden at noon, especially when the wind was blowing from the NW sector in the morning during summer time. This increased <i>N</i><sub>NUC</sub> and <i>N</i><sub>AIT</sub> by factors of 3.1 and 2.4, respectively. Nucleation events with the typical "banana" shape were characterised by a mean particle nucleation rate of 0.74 cm<sup>−3</sup> s<sup>−1</sup>, a mean growth rate of 1.96 nm h<sup>−1</sup> and a mean total duration of 9.25 h (starting at 10:55 GMT and ending at 20:10 GMT). They were observed for 48 days. Other nucleation events were identified as those produced by the emissions from the industrial areas located at a distance of 35 km. They were observed for 42 days. Both nucleation events were strongly linked to the marine air mass origin

    Study of mass and momentum transfer in diesel sprays base on X-ray mass distribution measurements and on a theoretical derivation

    Full text link
    [EN] In this paper, a research aimed at quantifying mass and momentum transfer in the near-nozzle field of diesel sprays injected into stagnant ambient air is reported. The study combines X-ray measurements for two different nozzles and axial positions, which provide mass distributions in the spray, with a theoretical model based on momentum flux conservation, which was previously validated. This investigation has allowed the validation of Gaussian profiles for local fuel concentration and velocity near the nozzle exit, as well as the determination of Schmidt number at realistic diesel spray conditions. This information could be very useful for those who are interested in spray modeling, especially at high-pressure injection conditions. © 2010 Springer-Verlag.This work was partly sponsored by "Vicerrectorado de Investigacion, Desarrollo e Innovacion'' of the "Universidad Politecnica de Valencia'' in the frame of the project "Estudio del flujo en el interior de toberas de inyeccion Diesel'', reference no. 3150 and by "Generalitat Valenciana'' in the frame of the project with the same title and reference GV/2009/031. This support is gratefully acknowledged by the authors.Desantes, J.; Salvador Rubio, FJ.; López, JJ.; De La Morena, J. (2011). Study of mass and momentum transfer in diesel sprays base on X-ray mass distribution measurements and on a theoretical derivation. Experiments in Fluids. 50(2):233-246. https://doi.org/10.1007/s00348-010-0919-8S233246502Abramovich GN (1963) The theory of turbulent jets. MIT Press, Cambridge, MAAdler D, Lyn WT (1969) The evaporation and mixing of a liquid fuel spray in a Diesel air swirl. Proc Instn Mech Eng 184:171–180Coghe A, Cossali GE (1994) Phase Doppler characterisation of a Diesel spray injected into a high density gas under vaporisation regimes. In: 7th international symposium on application of laser techniques to fluid mechanics, LisbonCorreas D (1998) Theoretical and experimental study of isothermal Diesel free sprays (in Spanish). PhD Thesis, Universidad Politécnica de ValenciaCossali GE (2001) An integral model for gas entrainment into full cone sprays. J Fluid Mech 439:353–366Dent JC (1971) A basis for the comparison of various experimental methods for studying spray penetration. SAE Paper 710571Desantes JM, Payri R, Salvador FJ, Gil A (2006a) Deduction and validation of a theoretical model for a free diesel Spray. Fuel 85:910–917Desantes JM, Arrègle J, López JJ, Cronhjort A (2006b) Scaling laws for free turbulent gas jets and Diesel-like sprays. Atomization Spray 16:443–473Desantes JM, Payri R, García JM, Salvador FJ (2007) A contribution to the understanding of isothermal diesel spray dynamics. Fuel 86:1093–1101Dumouchel C (2008) On the experimental investigation on primary atomization of liquid streams. Exp Fluids 45:371–422Heimgärtner C, Leipertz A (2000) of the primary spray break-up close to the nozzle of a common-rail high pressure diesel injection system. SAE Paper 2000-01-1799Hinze JO (1975) Turbulence. McGraw Hill, New YorkHiroyasu H, Arai M (1990) Structures of fuel sprays in diesel engines. SAE Paper 900475Jawad B, Gulari E, Henein NA (1992) Characteristics of intermittent fuel sprays. Combust Flame 88:384–396Lefèbvre AH (1989) Atomization and sprays. Hemisphere, New YorkLeick P, Riedel T, Bittlinger G, Powell CF, Kastengren AL, Wang J (2007) X-Ray measurements of the mass distribution in the dense primary break-up region of the spray from a standard multi-hole common-rail diesel injection system. In: Proc 21st ILASS (Europe)Linne M, Paciaroni M, Hall T, Parker T (2006) Ballistic imaging of the near field in a diesel spray. Exp Fluids 40:836–846Naber J, Siebers DL (1996) Effects of gas density and vaporisation on penetration and dispersion of diesel sprays. SAE Paper 960034Payri F, Bermúdez V, Payri R, Salvador FJ (2004) The influence of cavitation on the internal flow and the Spray characteristics in diesel injection nozzles. Fuel 83:419–431Payri R, García JM, Salvador FJ, Gimeno J (2005) Using spray momentum flux measurements to understand the influence of diesel nozzle geometry on spray characteristics. Fuel 84:551–561Payri R, Tormos B, Salvador FJ, Araneo L (2008) Spray droplet velocity characterization for convergent nozzles with three different diameters. Fuel 87:3176–3182Post S, Iyer V, Abraham J (2000) A study of near-field entrainment in gas jets and sprays under diesel conditions. ASME J Fluids Eng 122:385–395Prasad CMV, Kar S (1976) An investigation on the diffusion of momentum and mass of fuel in a diesel fuel spray. ASME J Eng Power 76-DGP-1:1–11Rajaratnam N (1976) Turbulent jets. Elsevier, AmsterdamRamirez AI, Som S, Aggarwal SK, Kastengren AL, El-Hannouny EM, Longman DE, Powell CF (2009) Quantitative X-ray measurements of high-pressure fuel sprays from a production heavy duty diesel injector. Exp Fluids 47:119–134Reitz RD, Bracco FV (1982) Mechanism of atomisation of a liquid jet. Phys Fluids 25(10):1730–1742Ricou FP, Spalding DB (1961) Measurements of entrainment by axisymmetrical turbulent jets. J Fluid Mech 11:21–32Rife J, Heywood JB (1974) Photographic and performance studies of diesel combustion with a rapid compression machine. SAE Paper 740948Roisman IV, Tropea C (2001) Flux measurements in sprays using phase doppler techniques. Atomization Spray 11:667–699Roisman IV, Araneo L, Tropea C (2007) Effect of ambient pressure on penetration of a diesel spray. Int J Multiphase Flow 33(8):904–920Saliba R, Baz I, Champoussin JC, Lance M, Marié JL (2004) Cavitation effect on the near nozzle spray development in high-pressure diesel injection. In: Proc 19th ILASS (Europe)Schlichting H (1978) Boundary layer theory. McGraw Hill, New YorkSinnamon JF, Lancaster DR, Stiener JC (1980) An experimental and analytical study of engine fuel spray trajectories. SAE Paper 800135Sou A, Hosokawa S, Tomiyama A (2007) Effects of cavitation in a nozzle on liquid jet atomization. Int J Heat Mass Tran 50(17–18):3575–3582Spalding DB (1979) Combustion and mass transfer. Pergamon Press, New YorkSubramaniam S (2001) Statistical modelling of a spray as using the droplet distribution function. Phys Fluids 13(3):624–642Tanner FX, Feigl A, Ciatti SA, Powell CF, Cheong S-K, Liu J, Wang J (2006) Structure of high-velocity dense sprays in the near-nozzle region. Atomization Spray 16:579–597Way RJB (1977) Investigation of interaction between swirl and jets in direct injection diesel engines using a water model. SAE Paper 770412Wu KJ, Santavicca DA, Bracco FV (1984) LDV measurements of drop velocity in diesel-type sprays. AAIA J 22(9):1263–1270Wu KJ, Reitz RD, Bracco FV (1986) Measurements of drop size at the spray edge near the nozzle in atomising liquid jets. Phys Fluids 29(4):941–951Yue Y, Powell CF, Poola R, Wang J, Schaller JK (2001) Quantitative measurements of diesel fuel spray characteristics in the near-nozzle region using X-ray absorption. Atomization Spray 11(4):471–49

    7th Drug hypersensitivity meeting: part two

    Get PDF
    No abstract availabl

    Role of age and comorbidities in mortality of patients with infective endocarditis

    Get PDF
    [Purpose]: The aim of this study was to analyse the characteristics of patients with IE in three groups of age and to assess the ability of age and the Charlson Comorbidity Index (CCI) to predict mortality. [Methods]: Prospective cohort study of all patients with IE included in the GAMES Spanish database between 2008 and 2015.Patients were stratified into three age groups:<65 years,65 to 80 years,and ≥ 80 years.The area under the receiver-operating characteristic (AUROC) curve was calculated to quantify the diagnostic accuracy of the CCI to predict mortality risk. [Results]: A total of 3120 patients with IE (1327 < 65 years;1291 65-80 years;502 ≥ 80 years) were enrolled.Fever and heart failure were the most common presentations of IE, with no differences among age groups.Patients ≥80 years who underwent surgery were significantly lower compared with other age groups (14.3%,65 years; 20.5%,65-79 years; 31.3%,≥80 years). In-hospital mortality was lower in the <65-year group (20.3%,<65 years;30.1%,65-79 years;34.7%,≥80 years;p < 0.001) as well as 1-year mortality (3.2%, <65 years; 5.5%, 65-80 years;7.6%,≥80 years; p = 0.003).Independent predictors of mortality were age ≥ 80 years (hazard ratio [HR]:2.78;95% confidence interval [CI]:2.32–3.34), CCI ≥ 3 (HR:1.62; 95% CI:1.39–1.88),and non-performed surgery (HR:1.64;95% CI:11.16–1.58).When the three age groups were compared,the AUROC curve for CCI was significantly larger for patients aged <65 years(p < 0.001) for both in-hospital and 1-year mortality. [Conclusion]: There were no differences in the clinical presentation of IE between the groups. Age ≥ 80 years, high comorbidity (measured by CCI),and non-performance of surgery were independent predictors of mortality in patients with IE.CCI could help to identify those patients with IE and surgical indication who present a lower risk of in-hospital and 1-year mortality after surgery, especially in the <65-year group

    Mejora del rendimiento escolar, a través de utilizar en el aula estrategias de tipo cognitivo

    No full text
    1) Aumentar la capacidad de aprendizaje de los alumnos de segunda etapa de EGB, deprimidos socio-culturalmente o que presenten una deficiencia mental límite o ligera, mediante la aplicación del programa de enriquecimiento instrumental de Reuven Feuerstein. 2) Hipótesis nula: la aplicación o no del programa no influye en la puntuación obtenida en el factor verbal (PMA). 3) Hipótesis alternativa: si se ha aplicado el programa, los alumnos puntuan más alto en los factores: verbal, espacial, razonamiento, numérico y fluidez verbal y en el test de autoconcepto de Piers-Harris. Alumnos de sexto de EGB de 4 centros públicos (dos grupos, uno experimental y otro de control en cada centro), y de escuelas hogares (un sólo grupo), de la provincia de Ciudad Real. Se han diseñado dos tratamientos estadísticos diferentes (para un sólo grupo y para dos). Las variables utilizadas son: 1) Independientes: programa de enriquecimiento instrumental de Reuven Feuerstein, con dos niveles de tratamiento: el grupo experimental, programas escolares ordinarios y el instrumental: el grupo de control, sólo el currículum escolar. 2) Variables dependientes: aptitudes mentales primarias, del PMA; autoconcepto de Piers-Harris. Matrices progresivas de Raven, test de aptitudes mentales primarias, PMA, de Thurstone, test de autoconcepto de Piers-Harris. T de Student, T de Wilcoxon, percentiles de distribuciones F. Resultados de tipo cuantitativo: en el diseño de dos grupos, la aplicación del programa no ha producido mejoras estadísticamente significativas en los factores medidos. En el diseño de un solo grupo, se han encontrado diferencias estadísticamente significativas en los factores: verbal y autoconcepto. Resultados de tipo cualitativo: en un solo grupo experimental, respecto a las funciones cognitivas, en la fase de entrada se aprecian logros muy significativos referidos a la búsqueda impulsiva. Se observan asímismo, avances importantes en orientación espacio-temporal y en la capacidad para relacionar dos fuentes de información a la vez. En la fase de elaboración no se observan progresos. En la fase de salida hay mejoras. La mejora del autoconcepto es evidente. Las relaciones profesor-alumnos progresan y hay una interacción muy positiva entre ambos. En el diseño de dos grupos la aplicación del programa no ha producido los efectos deseados. El programa se presenta como ideal para aquellos individuos con capacidad intelectual normal y que sufren deprivación socio-cultural.Castilla La ManchaBiblioteca de Educación del Ministerio de Educación, Cultura y Deporte; Calle San Agustín, 5 - 3 Planta; 28014 Madrid; Tel. +34917748000; Fax +34917748026; [email protected]

    Beyond ecology: ecosystem restoration as a process for social-ecological transformation

    No full text
    Ecosystem restoration conventionally focuses on ecological targets. However, while ecological targets are crucial to mobilizing political, social, and financial capital, they do not encapsulate the need to: integrate social, economic, and ecological dimensions and systems approaches; reconcile global targets and local objectives; and measure the rate of progress toward multiple and synergistic goals. Restoration is better conceived as an inclusive social-ecological process that integrates diverse values, practices, knowledge, and restoration objectives across temporal and spatial scales and stakeholder groups. Taking a more process-based approach will ultimately enable greater social-ecological transformation, greater restoration effectiveness, and more long-lasting benefits to people and nature across time and place

    DONES EVO: Risk mitigation for the IFMIF-DONES facility

    No full text
    The International Fusion Materials Irradiation Facility- DEMO Oriented Neutron Source (IFMIF-DONES) is a scientific infrastructure aimed to provide an intense neutron source for the qualification of materials to be used in future fusion power reactors. Its implementation is critical for the construction of the fusion DEMOnstration Power Plant (DEMO).IFMIF-DONES is a unique facility requiring a broad set of technologies. Although most of the necessary technologies have already been validated, there are still some aspects that introduce risks in the evolution of the project.In order to mitigate these risks, a consortium of companies, with the support of research centres and the funding of the CDTI (Centre for the Development of Industrial Technology and Innovation), has launched the DONES EVO Programme, which comprises six lines of research: • Improvement of signal transmission and integrity (planning and integration risks) • Optimisation of RF conditioning processes (planning and reliability risks) • Development of a reliable beam extraction device (reliability risks) • Development of technologies for the production of medical isotopes (reliability risks) • Improvement of critical parts of the lithium purification system (safety and reliability risks) • Validation of the manufacture of critical components with special materials (reliability risk).DONES EVO will focus on developing the appropriate response to the risks identified in the IFMIF-DONES project through research and prototyping around the associated technologies.This contribution will present a discussion of the risks, the proposed response to them and the evolution of the technologies involved, following selected experiments carried out throughout the project
    corecore