Theory of Weakly Exothermic Oblique Detonations

A simplified formulation, based on treating the ratio of the heat release to the postshock thermal enthalpy as a small parameter, accommodating arbitrary chemistry descriptions, is shown to reproduce computationally the same variety of phenomena as more complex formulations for oblique detonations with supersonic postshock flow. The resulting small relative variations of velocity and thermodynamic properties across the reaction region are described by linearized Euler equations written in characteristic form, supplemented by the linearized Rankine-Hugoniot jump conditions across the leading shock. The simplified formulation is used to analyze the interaction of the oblique detonation with a weak vortex sheet, for an Arrhenius irreversible reaction with an activation energy large compared with the postshock thermal enthalpy. The analysis reveals that, as ß, the product of the activation energy and the heat release divided by the square of the postshock thermal enthalpy, increases through values of order unity, decaying spatial oscillations, found for small values, are replaced by persistent nonlinear oscillations of finite amplitude for larger values. Beyond a critical value of ß the growth of the oscillation amplitude leads to the development of a singularity at the shock, an explosion, consistent with the formation of a triple point. Many related problems can be clarified with this formulation.The work of D.M.-R. and C.H. was supported by the Spanish Ministry of Science through Grant No. ENE2015-65852-C2-1-R) and by the Fundación Iberdrola España through Grant No. BYNVua37crdy. The work of A.L.S. and F.A.W. was supported by the U.S. AFOSR Grant No. FA9550-16-1-0443

La teoría de los principios científico-didácticos (P.C.D.) aplicada al cine como optimización de la enseñanza de la geografía y la historia

The rationale of this paper has grounds for the model of Scientific-Didactic Principles for teaching – learning of Geography and History created, published and introduced by García Ruiz and Jiménez López (2006 / 2007). The main idea behind this theory is that scientific principles must build the basis of learning of students in sciences, therefore they also a have a double didactic nature. In this paper we analyse, using this model, the “Gandhi” movie as an example of the didactic introduction of movies in classrooms in order to improve the quality of learnings in Geography and History.El fundamento de este trabajo se encuentra en la Teoría de los Principios CientíficoDidácticos para la enseñanza de la Geografía y de la Historia, creada y publicada por García Ruiz y Jiménez López (2006/2007). Estos autores defienden la idea de que los Principios Científicos deben constituir la base del aprendizaje geohistórico de los alumnos, lo que les otorga una doble naturaleza: científica y didáctica. Este artículo analiza la película “Gandhi” (1982) como ejemplo de la implementación didáctica del cine, en el marco de esta teoría, para mejorar la calidad de los aprendizajes de la Geografía y de la Historia

Interaction of Oblique Shocks and Laminar Shear Layers

This paper examines the steady interaction of a shear layer separating two uniform supersonic streams of Mach numbers M1 and M2 with an oblique shock approaching from the faster stream at an incident angle sigmai sufficiently small for the postshock flow to remain supersonic everywhere. The development begins by considering the related problem of oblique-shock impingement on a supersonic vortex sheet of infinitesimal thickness, for which the region of existence of regular shock refractions with downstream supersonic flow is delineated in the parametric space (M1,M2,sigmai). The interaction region located about the impingement point, scaling with the shear-layer thickness, is described next by integrating the Euler equations in the postshock region, formulated in characteristic form, subject to the Rankine-Hugoniot jump conditions at the shock front. The results are used to investigate the accuracy and limitations of a simplified treatment, the so-called Moeckel-Chisnell approach, commonly employed for determining the shape of the shock wave in these scenarios, which does not account for the influence of the postshock flow. It is found that, although the Moeckel-Chisnell method predicts accurately the shape of the shock front as it evolves across the shear layer, it is unable to predict the final transition to the transmitted-shock solution, which occurs beyond the edge of the shear layer. The structure of the shear layer in the far field also is addressed here for the first time, with the objective being to lay the groundwork for future studies of shock-induced ignition in supersonic fuel-air mixing layers.The work of A. L. Sánchez and F. A. Williams was supported by the U.S. Air Force Office of Scientific Research grant FA9550-16-1-0443, and that of D. Martínez-Ruiz and C. Huete was supported by the Spanish Ministry of Science (ENE2015-65852-C2-2-R) and the Fundación Iberdrola España (BYNV-ua37crdy)

Diffusion-Flame Ignition by Shock-Wave Impingement on a Hydrogen-Air Supersonic Mixing Layer

Ignition in a supersonic hydrogen-air mixing layer interacting with an oblique shock wave is investigated analytically under conditions such that the postshock flow is supersonic and the peak postshock temperature before ignition remains below the crossover temperature. The study requires consideration of the flow structure in the postshock ignition kernel found around the point of maximum temperature, which is assumed in this study to lie at an intermediate location across the mixing layer, as occurs in mixing layers subject to significant viscous dissipation. The ignition kernel displays a balance between the rates of chemical reaction and postshock flow expansion, including the acoustic interactions of the chemical heat release with the shock wave leading to increased front curvature. The problem is formulated with account taken of the strong temperature dependence of the chemical heat-release rate characterizing the ignition chemistry in the low-temperature regime analyzed here. It is shown how consideration of a two-step reduced chemical-kinetic mechanism derived in previous work leads to a boundary-value problem that can be solved analytically to determine ignition as a fold bifurcation, with the turning point in the diagram of peak perturbation induced by the chemical reaction as a function of the Damkohler number providing the critical conditions for ignition.This work was supported by the U.S. Air Force Office of Scientific Research grant FA9550-12-1-0138 and by the Spanish Ministerio de Ciencia e Innovación through the Program CONSOLIDER-Ingenio2010 (project CSD2010-00011).Publicad

Linear theory for the interaction of small-scale turbulence with overdriven detonation

To complement our previous analysis of interactions of large-scale turbulence with strong detonations, the corresponding theory of interactions of small-scale turbulence is presented here. Focusing most directly on the results of greatest interest, the ultimate long-time effects of high-frequency vortical and entropic disturbances on the burnt-gas flow, a normal-mode analysis is selected here, rather than the Laplace-transform approach. The interaction of the planar detonation with a monochromatic pattern of perturbations is addressed first, and then a Fourier superposition for two-dimensional and three-dimensional isotropic turbulent fields is employed to provide integral formulas for the amplification of the kinetic energy, enstrophy, and density fluctuations. Effects of the propagation Mach number and of the chemical heat release and the chemical reaction rate are identified, as well as the similarities and differences from the previous result for the thin-detonation (fast-reaction) limit.This work was supported by the U.S. AFOSR Grant No. FA9550-12-1-0138.Publicad

Cyber-aggression in adolescent couples: a cross-cultural study Spain-Mexico

El desarrollo de medidas válidas de la agresión en la pareja adolescente por medio de sitios de redes sociales y la mensajería instantánea es todavía escaso. El objetivo de este estudio fue analizar la equivalencia factorial de un ins-trumento de medida del control, la intrusión y los celos en línea en parejas adolescentes de España y México. Los parti-cipantes fueron 530 adolescentes con experiencia sentimen-tal (223 españoles, 51.57% chicas; 307 mexicanos, 49.35% chicas) y una edad media de 15.82 (España) y 16.30 (Méxi-co). Los análisis multigrupo mostraron una consistente equivalencia factorial de la escala. Las tasas de prevalencia fueron superiores al 70% en ambos países. Los adolescentes mexicanos obtuvieron una mayor puntuación en el control que los españoles, y los chicos mexicanos fueron más intru-sos que las chicas. Los resultados enfatizaron la equivalencia cultural de los constructos y las similitudes entre países en el comportamiento agresivo en línea de los adolescentes.Th e development of valid measures of adolescent dating aggression through social network sites and instant messages is still scarce. Th e aim of this study was to analyze the measurement invariance of an instrument assessing on-line control, intrusiveness and jealousy among adolescent couples in Spain and Mexico. Participants were 530 ado-lescents with romantic experience (223 Spanish, 51.57% girls; 307 Mexicans, 49.35% girls), mean aged 15.82 (Spain) and 16.30 (Mexico). Multi-group analyses showed a consistent factorial invariance of the measure. Prevalen-ce rates were higher than 70% in both countries. Mexi-can adolescents scored higher in control than Spaniards, and Mexican boys were more intrusive than girls. Results emphasized the cultural equivalence of the constructs and similarities between countries in adolescents’ aggressive online behavior

Cálculo y Álgebra con Mathematica 13

El cálculo infinitesimal e integral, y el álgebra lineal proporcionan herramientas básicas para abordar los problemas que surgen en ingeniería. Esta publicación muestra como el programa Mathematica facilita la resolución de dichos problemas. Los temas son expuestos de forma eminentemente práctica que hacen que, de modo natural, el lector asimile las posibilidades del programa a la vez que consolida conceptos teóricos que sustentan los métodos empleados. Los temas de Cálculo Matemático incluyen los números complejos, obtención de gráficas 2D y 3D y su manipulación interactiva, cálculo diferencial con funciones de una y varias variables, aplicaciones geométricas y físicas de la integral definida, curvilínea, doble, triple y de superficie, las integrales impropias y las series numéricas, de potencias y de Fourier. Los temas de Álgebra Lineal incluyen la resolución mínimo-cuadrática de sistemas y la diagonalización. Se presentan algunos métodos numéricos incorporados en el programa y se muestra como pueden ser implementados otros. También se expone su utilidad en la resolución de ecuaciones, sistemas de ecuaciones diferenciales ordinarias y problemas de valor inicial.Sánchez Ruiz, LM.; Moraño Fernández, JA. (2023). Cálculo y Álgebra con Mathematica 13. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/19807

Prevalence of tobacco consumption among young physicians at a regional university hospital in southern Spain: a cross-sectional study.

Introduction The aim of the study is to analyse the prevalence of smoking among resident physicians at a regional university hospital. In addition, we examined the trends in the smoking behaviour of physicians in relation to results obtained in other studies carried out previously at this hospital, as well as those published nationally and internationally Method A cross-sectional observational study evaluating tobacco consumption in young physicians was carried out at the level of secondary healthcare in a regional university hospital in Cordoba, Spain. All the study subjects were resident physicians who underwent a mandatory preliminary occupational health examination between 2012 and 2016. There was no sampling selection as anyone who took this examination was considered to be within the target population. We calculated the proportions of smokers, former smokers and non-smokers, with 95% CIs. Univariate and multivariate analyses (binary logistic regression) were used to analyse the results (P<0.05). Results The response rate was 99.4%, with a sample size of 324 out of a possible 326 physicians. The average age was 28.6±3.7—DT—(95% CI 28.2 to 29.0), and 62.3% (202/324; 95% CI 57.3 to 67.2) were women. Smoking prevalence was 6.5% (21/324; 95% CI 3.5 to 9.3) with a further 5.2% (17/324; 95% CI 2.7 to 7.8) being ex-smokers. There were no significant differences in the prevalence of tobacco consumption according to age (P=0.266), sex (9.0% for men and 5.0% for women; P=0.128), medical specialty (P=0.651) or year of residency (P=0.975). A 52.7% decline in the number of young physician smokers was noted between 1986 and 2016 (95% CI −44.0 to −63.5), together with a 64.4% increase in non-smokers (95% CI 55.2 to 77.3). Conclusions We observed a significantly low prevalence of tobacco use among trainee physicians in the cohort, an effect of new antismoking laws, with positive role model implications for new physicians and medical students.post-print285 K

Descripción de una especie nueva del género Athous Eschscholtz, 1829, de la Península Ibérica (Coleoptera: Elateridae: Dendrometrinae: Dendrometrini)

Se describe una especie nueva de Athous Eschscholtz, 1829 del subgénero Haplathous Reitter, 1905 de la península ibérica: A. (H.) dianae sp.n. Esta especie se ha encontrado hasta el momento únicamente en la provincia de Alicante, siendo la primera especie del subgénero Haplathous conocida para la Comunidad Valenciana.A new species of the genus Athous Escscholtz, 1829 subgenus Haplathous Reitter, 1905 is described from the Iberian Peninsula: Athous (Haplatous) dianae n.sp. At present this species is only known from the Alicante province, being the first species of Haplathous subgenus known form Valencian Community.Proyecto (PROMETEO/2013/034, I.P. Eduardo Galante) subvencionado por la Generalitat Valenciana

El turismo y la experiencia del cliente, una aproximación en la bibliometría española

El sector turístico ha evolucionado rápidamente desde sus orígenes con un turismo de masas y de sol y playa en España a final del pasado siglo hasta el actual turismo experiencial en el que el turista se caracteriza por la multimotivacionalidad. En este trabajo se analiza cómo la literatura turística española ha tratado esta temática sobre el análisis de la satisfacción y/o experiencia del turista y si se ha tratado la posible repercusión de la actual crisis económico-financiera sobre la misma.The tourism sector has rapidly evolved from its origins with mass tourism and sun and beach in Spain at the end of the last century to the present experiential tourism in which the tourist is characterized by multimotivacionalidad. This paper discusses how the Spanish tourist literature has addressed this issue on the analysis of satisfaction and / or experience of tourists and where there has been the potential impact of the current economic and financial crisis on it