Addition theorems for spin spherical harmonics. II Results

Based on the results of part I, we obtain the general form of the addition theorem for spin spherical harmonics and give explicit results in the cases involving one spin-$s'$ and one spin-$s$ spherical harmonics with $s',s=1/2$, 1, 3/2, and $|s'-s|=0$, 1. We obtain also a fully general addition theorem for one scalar and one tensor spherical harmonic of arbitrary rank. A variety of bilocal sums of ordinary and spin spherical harmonics are given in explicit form, including a general explicit expression for bilocal spherical harmonics

Effect of boosting system architecture and thermomechanical limits on diesel engine performance: Part I -Steady-state operation

[EN] Internal combustion engine developments are more focused on efficiency optimization and emission reduction for the upcoming future. To achieve these goals, technologies like downsizing and downspeeding are needed to be developed according to the requirement. These modifications on thermal engines are able to reduce fuel consumption and CO2 emission. However, implementation of these kind of technologies asks for right and efficient charging systems. This article consists of study of different boosting systems and architectures (single- and two-stage) with combination of different charging systems like superchargers and e-boosters. A parametric study is carried out with a zero-dimensional engine model to analyze and compare the effects of these different architectures on the same base engine. The impact of thermomechanical limits, turbo sizes and other engine development option characterizations are proposed to improve fuel consumption, maximum power and performance of the downsized/downspeeded diesel engines.Galindo, J.; Climent, H.; Varnier, O.; Patil, CY. (2018). Effect of boosting system architecture and thermomechanical limits on diesel engine performance: Part I -Steady-state operation. International Journal of Engine Research. 19(8):854-872. https://doi.org/10.1177/1468087417731654S85487219

Effect of boosting system architecture and thermomechanical limits on diesel engine performance: Part II - Transient operation

[EN] Nowadays, internal combustion engine developments are focused on efficiency optimization and emission reduction. Increasing focus on world harmonized ways to determine the performance and emissions on Worldwide harmonized Light vehicles Test Procedure cycles, it is essential to optimize the engines for transient operations. To achieve these objectives, the downsized or downspeeded engines are required, which can reduce fuel consumption and pollutant emissions. However, these technologies ask for efficient charging systems. This article consists of the study of different boosting architectures (single stage and two stage) with a combination of different charging systems like superchargers and e-boosters. A parametric study has been carried out with a zero-dimensional engine model to analyze and compare different architectures on the different engine displacements. The impact of thermomechanical limits, turbo sizes and other engine development option characterizations is proposed to improve fuel consumption, maximum power and performance of the downsized/downspeeded diesel engines during the transient operations.Galindo, J.; Climent, H.; Varnier, O.; Patil, CY. (2018). Effect of boosting system architecture and thermomechanical limits on diesel engine performance: Part II - Transient operation. International Journal of Engine Research. 19(8):873-885. https://doi.org/10.1177/1468087417732264S87388519

L?dica y did?ctica en el proceso de ense?anza-aprendizaje de las ciencias naturales, para los estudiantes de grado tercero del colegio liceo de los Alpes

79 p. Recurso Electr?nicoEsta clase de investigaci?n es de tipo cualitativa-descriptiva, cuyo objetivo fue implementar estrategias l?dico-did?cticas en el proceso de ense?anza-aprendizaje de las ciencias naturales para estudiantes de grado tercero en un colegio privado en Bogot?, Colombia. Durante el desarrollo de la investigaci?n se emplearon instrumentos eficaces para la recolecci?n de informaci?n, los cuales fueron la observaci?n directa, la encuesta, la entrevista, con el fin de describir diferentes aspectos en el desarrollo de las clases de ciencias naturales, la participaci?n activa, el ambiente del aula, la interacci?n del docente-alumno y entre pares. Se logr? evidenciar que, mediante la aplicaci?n de las diferentes actividades l?dicas como rompecabezas, domin?, parqu?s, escaleras, los educandos lograron no solo aprender los diversos temas, sino que adem?s, se vio que ellos mejoraron notoriamente en su desarrollo socio-afectivo y creativo. Por otro lado se pudo evidenciar que la l?dica como parte central del proceso de ense?anza-aprendizaje, influye en las acciones ?aprender? y ?jugar? las cuales se entrelazan para generar resultados ?ptimos de aprendizaje, debido a que fortalecen las habilidades de, deducir, inventar, adivinar y argumentar. Palabras Clave: Juego, L?dica, did?ctica, ense?anza, aprendizaje, habilidades, motivaci?n, participaci?n, proceso.This qualitative-descriptive research study, whose purpose was to implement ludic-didactic strategies in the teaching-learning process of the natural sciences for third-grade students at a private school in Bogot?, Colombia. During the development of these research, effective data gathering instruments were applied, the instruments were, direct observation, survey, interview, these were used to describe the different aspects of the development of natural science classes, active participation, classroom environment, teacher-student and peer interaction. It was possible to show that, through the application of the different ludic activities such as puzzles, dominoes, plans, learners not only to learn the various subjects, but also; we could see that they excelled in their socio-creative and creative development. On the other hand, it was evident that ludic as a central part of the teaching-learning process, influences the "learn" and "play" actions which are intertwined to generate optimal learning results, because they strengthen the skills of, deduce, invent, guess and argue. Keywords: Game, ludic, didactics, teaching, learning, abilities, motivation, participation, process

Empirical estimation of peak pressure level from sound exposure level. Part II: Offshore impact pile driving noise

Numerical models of underwater sound propagation predict the energy of impulsive signals and its decay with range with a better accuracy than the peak pressure. A semi-empirical formula is suggested to predict the peak pressure of man-made impulsive signals based on numerical predictions of their energy. The approach discussed by Galindo-Romero, Lippert, and Gavrilov [J. Acoust. Soc. Am. 138, in press (2015)] for airgun signals is modified to predict the peak pressure from offshore pile driving, which accounts for impact and pile parameters. It is shown that using the modified empirical formula provides more accurate predictions of the peak pressure than direct numerical simulations of the signal waveform

Scintillation light produced by low-energy beams of highly-charged ions

Measurements have been performed of scintillation light intensities emitted from various inorganic scintillators irradiated with low-energy beams of highly-charged ions from an electron beam ion source (EBIS) and an electron cyclotron resonance ion source (ECRIS). Beams of xenon ions Xe$^{q+}$ with various charge states between $q$=2 and $q$=18 have been used at energies between 5 keV and 17.5 keV per charge generated by the ECRIS. The intensity of the beam was typically varied between 1 and 100 nA. Beams of highly charged residual gas ions have been produced by the EBIS at 4.5 keV per charge and with low intensities down to 100 pA. The scintillator materials used are flat screens of P46 YAG and P43 phosphor. In all cases, scintillation light emitted from the screen surface was detected by a CCD camera. The scintillation light intensity has been found to depend linearly on the kinetic ion energy per time deposited into the scintillator, while up to $q$=18 no significant contribution from the ions' potential energy was found. We discuss the results on the background of a possible use as beam diagnostics e.g. for the new HITRAP facility at GSI, Germany.Comment: 6 pages, 8 figure

Addition theorems for spin spherical harmonics. I Preliminaries

We develop a systematic approach to deriving addition theorems for, and some other bilocal sums of, spin spherical harmonics. In this first part we establish some necessary technical results. We discuss the factorization of orbital and spin degrees of freedom in certain products of Clebsch-Gordan coefficients, and obtain general explicit results for the matrix elements in configuration space of tensor products of arbitrary rank of the position and angular-momentum operators. These results are the basis of the addition theorems for spin spherical harmonics obtained in part II