Experimental study of the effect of nozzle geometry on the performance of direct-injection diesel sprays for three different fuels

This thesis studies the influence of internal nozzle flow characteristics over a large spectrum of experimental conditions and diagnostics. Experiments were carried out for two nozzle geometries---cylindrical and conical single hole nozzles---and three different fuels. Two of the fuels are pure components---n-heptane and n-dodecane---while the third fuel consists of a three-component surrogate to better represent the physical and chemical properties of diesel fuel. Measurements include a complete hydraulic characterization consisting of instantaneous injection rate and spray momentum flux measurements; a high-speed visualization of isothermal liquid spray; a high-speed visualization of the evaporative inert spray, imaging liquid and vapor phases simultaneously and finally, a high-speed visualization of the high temperature reactive spray, imaging vapor phase and OH* chemiluminescence for each injection event. All high-temperature diagnostics were performed in a continuous flow test chamber that allows an accurate control on a wide range of thermodynamic conditions (up to 1000 K and 15 MPa). The experimental findings from this work, and the large database obtained (available for download at: http://www.cmt.upv.es/DD01.aspx), could be used to validate CFD models that could help the community understand the fundamental driving mechanisms behind these observations.En esta tesis se estudia la influencia del flujo interno sobre un amplio espectro de condiciones y diagnósticos experimentales. Se realizaron experimentos para dos geometrías de tobera---toberas cilíndrica y cónica de un único orificio---y tres combustibles. Dos de los combustibles son puros---n-heptano y n-dodecano--- mientras el tercero es un combustible sustituto que consiste en una mezcla de tres componentes que busca representar mejor las propiedades físicas y químicas del diesel. Las medidas incluyen una caracterización hidráulica completa, compuesta por tasa de inyección y cantidad de movimiento instantáneas; una visualización de alta velocidad del chorro líquido isotermo; una visualización de alta velocidad del chorro inerte evaporativo, con captura simultánea de las fases líquida y vapor y, finalmente, una visualización del chorro reactivo a alta temperatura, con captura de la fase vapor y la quimioluminiscencia del radical OH* para cada evento de inyección. Todos los diagnósticos en condiciones de alta temperatura fueron realizados en una maqueta de alta presión y temperatura de flujo constante que permite controlar con precisión un rango amplio de condiciones termodinámicas (hasta 1000 K y 15 MPa). Los resultados experimentales y la gran base de datos obtenida en este trabajo (disponible en: http://www.cmt.upv.es/DD01.aspx), podrían ser utilizados para validar modelos CFD detallados que podrían ayudar a la comunidad científica a entender mejor los mecanismos fundamentales que producen los resultados observados.Aquesta tesi estudia la influència del flux intern sobre un gran espectre de condicions i diagnòstics experimentals. Es van realitzar experiments per a dos geometries de tovera---toveres ci¿líndrica i cónica amb un únic orifici---i tres combustibles. Dos dels combustibles són purs---n-heptà i n-dodecà--- mentre el tercer combustible consisteix en una mescla de tres components que formen un combustible substitut que busca representar millor les propietats físiques i químiques del dièsel. Les mesures inclouen una caracterització hidràulica completa, composta per taxa d'injecció i quantitat de moviment instantanis; visualització d'alta velocitat del doll líquid isoterme; visualització d'alta velocitat del doll inert evaporatiu, capturant simultàniament les fases líquid i vapor i, finalment, una visualització del doll reactiu a alta temperatura, capturant la fase vapor i la quimioluminiscència del radical OH per a cada esdeveniment d'injecció. Tots els diagnòstics en condicions d'alta temperatura van ser realitzats en una insta¿lació d'alta pressió i temperatura amb flux constant que permet controlar amb precisió un ampli rang de condicions termodinàmiques (fins a 1000 K i 15 MPa). Els resultats experimentals i la gran base de dades obtinguda en aquest treball (disponible a la web en: http://www.cmt.upv.es/dd01.aspx), podrien ser utilitzats per tal de validar models CFD detallats que podrien ajudar a la comunitat científica a entendre millor els mecanismes fonamentals que produeixen aquestes observacions.Viera Sotillo, JP. (2017). Experimental study of the effect of nozzle geometry on the performance of direct-injection diesel sprays for three different fuels [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/81857TESI

The effect of nozzle geometry over the evaporative spray formation for three different fuels

[EN] The influence of internal nozzle flow characteristics over the evaporative spray development is studied experimentally for two different nozzle geome-tries and three different fuels. This is a continuation of previous work by the authors where non-evaporative isothermal spray development was stud-ied experimentally for the same nozzle geometries and fuels. Current study reports macroscopic spray characteristics by imaging the liquid and vapor phases of the spray simultaneously using independent cameras and optical techniques. The liquid phase is captured by a fast-pulsed diffused back illumination setup, while the vapor phase is captured by a single-pass Schlieren setup with diaphragm. The nozzle geometries consist of a conical nozzle and a cylindrical nozzle with 8.6 % larger outlet diameter when compared to the conical nozzle. Among the three fuels, two are pure components n-heptane and n-dodecane while the third consists of a three-component surrogate to better represent the physical and chemical properties of diesel fuel. For a fixed ambient density, the liquid penetration is controlled by ambient temperature while the vapor penetration is controlled by injection pressure. The cylindrical nozzle, in spite of higher mass flow rate and momentum flux,shows slower vapor spray tip penetration when compared to the conical noz-zle. Also, the cylindrical nozzle consistently produced shorter liquid lengths. The vapor spray spreading angle is found to be inversely proportional to the spray tip penetration, largely influenced by the nozzle geometry and the am-bient density. n-Heptane spray shows the shortest liquid lengths, followed by n-dodecane and finally the Surrogate. No significant difference in vapor penetration rates was found between fuels, confirming that the vapor spray is controlled by momentum, which is independent of fuel. This was not the case for the non-evaporative isothermal sprays previously studied by the au-thors. Liquid lengths show the expected responses to parametric variations of ambient temperature and density. Two empirical predictive models are presented and utilized to analyze the influence of fuel properties on the liq-uid length. The primary factor controlling the liquid length between fuels is found to be their volatility. Finally, the cylindrical nozzle exhibits larger line-of-sight contour fluctuations in both the liquid and vapor phases, which in turn contributes to the shorter liquid lengths and slower vapor penetration.This work was sponsored by Ministerio de Economía y Competitividad of the Spanish Government in the frame of the Project “Estudio de la interaccin chorro-pared en condiciones realistas de motor”, Reference TRA2015-67679-c2-1-R. Additionally, the employed nozzles and Diesel surrogate were provided and defined by GM R&D. The authors would like to thank José Enrique Del Rey and María del Carmen Tomás for their collaboration in the setup of the experiments and laboratory work, and Guillermo Miró for his help measuring fuel properties.Payri, R.; Viera-Sotillo, JP.; Gopalakrishnan, V.; Szymkowicz, P. (2017). The effect of nozzle geometry over the evaporative spray formation for three different fuels. Fuel. 188:645-660. https://doi.org/10.1016/j.fuel.2016.10.064S64566018

Afectación de la inhibición cognitiva sobre la memoria en personas con discapacidad intelectual: Un meta-análisis.

Background: Cognitive inhibition impairment is intimately related to the forgetfulness of relevant information. This meta-analysis aims to synthesise the evidence of impaired function of cognitive inhibition processes over memory in individuals with intellectual disability (ID). Method: Eleven studies were selected and analysed and included a total of 683 participants. The studies were categorised according to variables such as the task used, the processes involved, the sensory modalities and the method. Results: Despite the small sample of studies, the results revealed signifi cant diffi culties with cognitive memory inhibition (CMI) tasks in individuals with ID compared with typical development (TD) individuals (d = 0.62). CMI problems were found in all life stages except the 19-45- year-old stage. In this stage, there was a smaller amount of evidence even though it included the 31-40-year-old range, during which premature aging has been observed in ID. Conclusions: An impairment of CMI in people with ID was observed. More studies are needed to more reliably assess the potential moderating role of age and other factors.Antecedentes: la afectación de la inhibición cognitiva se encuentra íntimamente relacionada con el olvido de información relevante. Este meta-análisis tiene como objetivo conocer si los procesos de inhibición cognitiva sobre la memoria están afectados en personas con discapacidad intelectual (DI). Método: se seleccionaron y analizaron 11 estudios que incluyeron un total de 683 participantes. Los artículos fueron categorizados en función de la tarea utilizada, los procesos implicados, las modalidades sensoriales y el método. Resultados: a pesar del número de estudios, se observaron difi cultades signifi cativas en inhibición cognitiva sobre la memoria (ICM) en personas con DI, en comparación con personas con desarrollo típico (d = 0.62). Estas difi cultades se observaron en todas las etapas cronológicas, excepto de 19 a 45 años. En esta etapa, la evidencia fue escasa, a pesar de incluir el rango de los 31-40 años, donde se ha observado presencia de envejecimiento prematuro en personas con DI. Conclusiones: se observaron difi cultades en ICM en personas con DI. Se necesitan más estudios para evaluar de forma más exhaustiva el papel potencialmente moderador de la edad y de otros factores.Part of this work has been supported by “Autour des Williams”. Project “Inhibitory processes and memory mechanisms in adults with Williams syndrome: A neuropsychological and functional connectivity approach using magnetoencephalography”

The effect of nozzle geometry over ignition delay and flame lift-off of reacting direct-injection sprays for three different fuels

[EN] The influence of internal nozzle flow characteristics over ignition delay, and flame lift-off of reacting direct-injection sprays is studied experimentally for three fuels using two different nozzle geometries. This is a continuation of previous work by the authors, where, evaporative and non-evaporative, isothermal spray developments were studied experimentally for the same nozzle geometries and fuels. Current study reports the ignition delay through Schlieren technique, and flame lift-off length through OH* chemiluminescence visualization. The nozzle geometries consist of a conical nozzle and a cylindrical nozzle with 8.6% larger outlet diameter when compared to the conical nozzle. The three fuels considered are n-heptane, n-dodecane and a three-component surrogate to better represent the physical and chemical properties of diesel fuel. Reacting spray is found to penetrate faster than non-reacting spray due to combustion induced acceleration after ignition. Higher oxygen concentration, and ambient temperature enhance the reactivity leading to higher spray tip penetration. Injection pressure does not affect the reactivity significantly and hence, influences spray penetration through momentum-similar to a non-reacting spray. Both ignition delay and lift-off length are found to be shortest and longest for n-dodecane and n-heptane, respectively, while the surrogate fuel falls in-between the two pure component fuels. Both ignition delay and lift-off length are found to decrease with increase in oxygen concentration, ambient temperature, and density. The cylindrical nozzle, in spite of shorter lift-off length is found to have longer ignition delay, when compared to the conical nozzle. This could be due to better atomization leading to larger spread angle and evaporative cooling from the cylindrical nozzle compared to a conical nozzle. The longer ignition delay also leads to leaner equivalence ratios at the time of ignition. (C) 2017 Elsevier Ltd. All rights reserved.This work was sponsored by Ministerio de Economia y Competitividad of the Spanish Government in the frame of the Project "Estudio de la interaccion chorro-pared en condiciones realistas de motor", Reference TRA2015-67679-c2-1-R. Additionally, the employed nozzles and Diesel surrogate were provided and defined by GM R&D.Payri, R.; Viera-Sotillo, JP.; Gopalakrishnan, V.; Szymkowicz, P. (2017). The effect of nozzle geometry over ignition delay and flame lift-off of reacting direct-injection sprays for three different fuels. Fuel. 199:76-90. https://doi.org/10.1016/j.fuel.2017.02.075S769019

Wearable Postural Control System for Low Back Pain Therapy

© 2021 IEEE. This version of the article has been accepted for publication, after peer review. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. The Version of Record is available online at: https://doi.org/10.1109/10.1109/TIM.2021.3057935[Abstract]: Treatment of low back pain usually includes exercise, analgesics, prostheses, and, in severe cases, surgery. Early treatments based on postural control are essential to prevent low back pain and mitigate permanent damage. We present a wearable device, with an estimated cost below U.S. $100, which uses inertial units with triaxial accelerometers, gyroscopes, and magnetometers to measure the orientation of three sections of the spine. The device integrates the absolute and relative orientation from the sensors to estimate the posture of the back in real-time and uses a fuzzy system to control a vibration unit that indicates the user when to correct the posture of the back. We validated the device in controlled conditions, obtaining an rms deviation ≤1.24° and conducted a preliminary clinical pilot study with patients afflicted by lumbar hyperlordosis or lumbar hypolordosis. We observed an improved postural control and a reduction of low back pain in all cases. These results show a promising potential of the device to reduce pain, improve postural therapies, and raise postural awareness in patients affected with low back pain

The effect of nozzle geometry over internal flow and spray formation for three different fuels

The influence of internal nozzle flow characteristics over macroscopic spray development is studied experimentally for two different nozzle geometries and three fuels. The measurements include a complete hydraulic characterization consisting of instantaneous injection rate and spray momentum flux measurements, followed by a high-speed visualization of isothermal liquid spray in combination with cylindrical and conical nozzle configurations. Two of the fuels are pure components n-heptane and n-dodecane while the third fuel consists of a three-component surrogate to better represent the physical and chemical properties of diesel fuel. The cylindrical nozzle with 8.6 % larger diameter, in spite of higher mass flow rate and momentum flux, shows slower spray tip penetration when compared to the conical nozzle. The spreading angle is found to be inversely proportional to the spray tip penetration. The spreading angle is largely influenced by the nozzle geometry and the ambient density. Rail pressure was found to have weak influence on the near-field spreading angle and no influence on the standard deviation of the spreading angle. n-Heptane spray shows slowest penetration rates while n-dodecane and the surrogate fuel mixture show very similar spray behavior for variations in injection pressure and back pressure. However, the surrogate fuel mixture shows higher penetration than n-dodecane when using the conical nozzle and lower penetration than n-dodecane when using cylindrical nozzle.This work was sponsored by Ministerio de Economia y Competitividad of the Spanish Government in the frame of the Project "Estudio de la interaccin chorro-pared en condiciones realistas de motor", Reference TRA2015-67679-c2-1-R. Additionally, the employed nozzles and diesel surrogate were provided and defined by GM R&D.Payri Marín, R.; Viera Sotillo, JP.; Gopalakrishnan, V.; Szymkowicz, PG. (2016). The effect of nozzle geometry over internal flow and spray formation for three different fuels. Fuel. 183:20-33. doi:10.1016/j.fuel.2016.06.041S203318

Logros y retos de la política europea de cooperación internacional para el desarollo

Si bien la Unión Europea (UE), debido a su importante contribución a la cooperación internacional para el desarrollo es considerada la principal potencia solidaria del planeta, aún enfrenta importantes retos en la materia. Un ejemplo de ello es la incapacidad europea de instrumentar estrategias suficientemente coherentes respecto a otras acciones de influencia exterior, tales como la ayuda, en compatibilidad con la seguridad, el comercio y la migración. El artículo argumenta que, con todo y sus avances, la UE debe conseguir mejores niveles de coordinación en temas clave de su acción exterior, si lo que desea es constituirse como un actor consolidado y eficaz de cooperación para el desarrollo.Palavras-chave: cooperação internacional para o desenvolvimento, União Européia, coordenação

To Emilio Jardón Dato

EditorialConocimos a Emilio en mayo de 1991, cuando vino a tomar posesión de su puesto de trabajo como jefe de la Unidad de Valoración Médica de Incapacidades de Madrid (UVMI), encuadrada en la estructura del Instituto Nacional de la Salud, situada en la Clínica del Trabajo, en la tercera planta del número 21 de la calle Reina Victoria de Madrid. En esos momentos, la UVMI disponía de una plantilla de 10 médicos inspectores para realizar tanto los informes de valoración de la incapacidad permanente en el área nacional e internacional como las valoraciones de incapacidad temporal de más de 12 meses de duración para autorizar la prórroga de la antigua incapacidad laboral transitoria como el pase a la extinta invalidez provisional, así como para el resto de los informes para las distintas prestaciones de seguridad social. Eran tiempos de escasez de medios humanos y materiales en la UVMI, superados en parte con su ayuda y entusiasmo. En esos años empezó a tomar cuerpo un nuevo proyecto de integración de las UVMI en la estructura del Instituto Nacional de la Seguridad Social (INSS). Emilio fue un firme defensor de este proyecto desde su inicio, convencido de que la incorporación de las unidades de valoración médica de incapacidades a la estructura de las Direcciones Provinciales del INSS supondría una mejora importante tanto para los asegurados al sistema de la Seguridad Social como en el reconocimiento de la labor profesional de los médicos inspectores y en la disponibilidad de medios materiales y humanos para llevar a cabo sus funciones.N

Logros y retos de la política europea de cooperación internacional para el desarollo

Si bien la Unión Europea (UE), debido a su importante contribución a la cooperación internacional para el desarrollo es considerada la principal potencia solidaria del planeta, aún enfrenta importantes retos en la materia. Un ejemplo de ello es la incapacidad europea de instrumentar estrategias suficientemente coherentes respecto a otras acciones de influencia exterior, tales como la ayuda, en compatibilidad con la seguridad, el comercio y la migración. El artículo argumenta que, con todo y sus avances, la UE debe conseguir mejores niveles de coordinación en temas clave de su acción exterior, si lo que desea es constituirse como un actor consolidado y eficaz de cooperación para el desarrollo.Palavras-chave: cooperação internacional para o desenvolvimento, União Européia, coordenação

Influence of grain processing in regard to serum metabolites and enzymes for finishing bull calves

This study compared two grain processing methods that are widely used for beef cattle, grinding and steam pelleting, with respect to serum metabolic parameters: glucose, non-esterified fatty acids (NEFA), serum urea nitrogen (SUN), total serum protein (TSP), albumin, L-lactate, aspartate aminotransferase (AST), γ-glutamyltransferase (GGT) and amylase. Ten Belgian Blue bull calves were allotted randomly to each of two experimental groups: PF, fed pelleted concentrate, and GF, fed ground concentrate. During the 77-day study most parameters underwent significant variation in time, increasing only numerically serum values of total protein, albumin, AST and amylase, while serum glucose, NEFA and GGT decreased numerically. Statistically significant differences were found only between groups PF and GF for creatinine (higher in group PF, in relation with its greater average body weight) and urea nitrogen, which for unknown causes fluctuated in opposite directions in the two groups throughout most of the study and attributable to changes in ruminal protein digestion. Neither serum glucose nor L-lactate were affected by treatment of grainsSupported by the Xunta de Galicia (Spain), Grant XUGA 2002/CG320S