Visualizing the Doppler Effect

The development of Information and Communication Technologies suggests some spectacular changes in the methods used for teaching scientific subjects. Nowadays, the development of software and hardware makes it possible to simulate processes as close to reality as we want. However, when we are trying to explain some complex physical processes, it is better to simplify the problem under study using simplified pictures of the total process by eliminating some elements that make it difficult to understand this process. In this work we focus our attention on the Doppler effect which requires the space-time visualization that is very difficult to obtain using the traditional teaching resources. We have designed digital simulations as a complement of the theoretical explanation in order to help students understand this phenomenon.Comment: 16 pages, 8 figure

Modelo de gestión financiera para la Cooperativa de Ahorro y Crédito Mushuc Runa Ltda. Sucursal Riobamba periodo 2014

El presente trabajo de investigación indaga la singularidad en el procedimiento de la estructuración de un Modelo de Gestión Financiera para la Cooperativa de Ahorro y Crédito “Mushuc Runa” Ltda., Sucursal Riobamba, Período 2014, tomando en consideración las debilidades que presenta la Institución Financiera en su estructura operativa. La investigación consta de cinco capítulos; en el Primer Capítulo se expone a detalle la problematización del trabajo de investigación, seguidamente en el Segundo Capítulo se analiza la parte teórica que permite tener una idea clara de lo que es un Modelo de Gestión Financiera, a continuación en el Tercer Capítulo se determina el marco metodológico y su aplicación y en el Cuarto Capítulo se realiza la estructuración del Modelo de Gestión Financiera con su respectivo análisis, el cual inicia con un diagnóstico para conocer de la situación financiera de la cooperativa, se realiza proyecciones y al final se da a conocer la situación de manera general de la Cooperativa a fin de establecer una correcta administración sobre la cual sustenta la estructura del modelo, estableciendo las respectivas estrategias financieras. Al final, en el Quinto Capítulo se establecen las respectivas conclusiones y recomendaciones y se concluye en que el Modelo de Gestión Financiera planteado constituye para la Cooperativa de Ahorro y Crédito “Mushuc Runa” Ltda., Sucursal Riobamba un mecanismo indispensable que se debería aprovechar para transformar sus debilidades en oportunidades para fortalecer el crecimiento y desarrollo sostenido de la institución. El presente estudio propone la alternativa más eficiente y versátil en la estructuración de un Modelo de Gestión Financiera para la Cooperativa de Ahorro y Crédito “Mushuc Runa Ltda.” Sucursal Riobamba, Periodo 2014.The present research is about the design procedure of a Financial Management model for Savings and Credit union ‘‘ Mushuc Runa’’ Ltda., branch office Riobamba in 2014 taking into account the weaknesses having the financial institution in its operational structure. This research has five chapters. In the first one, investigation work problem is exposed, in the second one, theory is analyzed to get a clear idea about Financial Management Model, in the third one, methodological frame and its application are determined and in the fourth one, Financial Management Model design and its analysis were carried out. This analysis starts with a diagnosis to know the financial union situation. Projections are carried out to know the general situation of the union in order to establish a better management to sustain the model structure by establishing the corresponding financial strategies. In the fifth chapter, conclusions and recommendations were established and it is concluded that the financial management model planted above constitutes an indispensable device which must be taken in advantage to transform its weaknesses into opportunities to strengthen the increase and sustainable development of the institution. The present study proposes the most efficient and versatile alternative in the design of Financial Management Model for Savings and Credit union ‘‘Mushuc Runa’’ Ltda., branch office Riobamba in 2014

Evaluation of Interphase Drag Models for the Determination of Gas Hold-Up of an Air-Water System in a Spouted Bed using CFD

Abstract: The hydrodynamics of a dispersed air-water system within a spouted column with a concentric draft tube and a conical base is simulated using CFD based on a two–fluid Euler–Euler (E-E) modeling framework and k-ε two-equation turbulence closures. The interaction between the dispersed gas phase and the continuous liquid phase is characterized by bubble–liquid interphase forces (drag, turbulent dispersion and lift forces). The Ishii-Zuber drag model [1] and Grace adjusted drag model [2], the latter represented by: GraceDpg Grace dense D C C , , are compared for their capability to match experimental gas hold- up. Numerical results of Reynolds-averaged Navier-Stokes equations with k-ε two-equation turbulence closures models when compared with Pironti experimental data [3] indicated that both drag models, predicted the air hold-up within experimental error. Furthermore, Ishii-Zuber liquid-gas drag model consistently provided better agreement of experimental results; it correctly determines the hold-up within 0.14%. Numerical agreement with adjusted Grace liquid-gas drag model, is exponent dependent 4 p 0.5, turning down that the best computed hold-up is within 0.44%. for p 0.5

Evaluation of Interphase Drag Models for the Determination of Gas Hold-Up of an Air-Water System in a Spouted Bed using CFD

Abstract: The hydrodynamics of a dispersed air-water system within a spouted column with a concentric draft tube and a conical base is simulated using CFD based on a two–fluid Euler–Euler (E-E) modeling framework and k-ε two-equation turbulence closures. The interaction between the dispersed gas phase and the continuous liquid phase is characterized by bubble–liquid interphase forces (drag, turbulent dispersion and lift forces). The Ishii-Zuber drag model [1] and Grace adjusted drag model [2], the latter represented by: GraceDpg Grace dense D C  C , , are compared for their capability to match experimental gas hold- up. Numerical results of Reynolds-averaged Navier-Stokes equations with k-ε two-equation turbulence closures models when compared with Pironti experimental data [3] indicated that both drag models, predicted the air hold-up within experimental error. Furthermore, Ishii-Zuber liquid-gas drag model consistently provided better agreement of experimental results; it correctly determines the hold-up within 0.14%. Numerical agreement with adjusted Grace liquid-gas drag model, is exponent dependent 4  p  0.5, turning down that the best computed hold-up is within 0.44%. for p  0.5

Measuring coupled oscillations using an automated video analysis technique based on image recognition

[EN] The applications of the digital video image to the investigation of physical phenomena have increased enormously in recent years. The advances in computer technology and image recognition techniques allow the analysis of more complex problems. In this work, we study the movement of a damped coupled oscillation system. The motion is considered as a linear combination of two normal modes, i.e. the symmetric and antisymmetric modes. The image of the experiment is recorded with a video camera and analysed by means of software developed in our laboratory. The results show a very good agreement with the theory.This work has received financial support by the Universidad Polit¿ecnica de Valencia (PII20020632), Spain. We would like to thank the R+D+I Linguistic Assistance Office at the Universidad Politècnica de Valencia for their help in revising this paper.Monsoriu Serra, JA.; Gimenez Valentin, MH.; Riera Guasp, J.; Vidaurre, A. (2005). Measuring coupled oscillations using an automated video analysis technique based on image recognition. European Journal of Physics. 26(6):1149-1155. https://doi.org/10.1088/0143-0807/26/6/023S1149115526

Seed Germination Behaviour in Sideritis from Different Iberian Habitats

[EN] The germination behaviour of two Iberian endemic labiates, Sideritis pungens and S. chamaedryfolia selected from different habitats, ranging from very humid to semi-arid, was studied under controlled experimental conditions. A factorial experiment, combining different temperature regimes (10 degrees, 15 degrees, 20 degrees, 25 degrees or 30 degrees C), photoperiod (total darkness and 12 h light/12 h darkness) and different pre-treatments (freezing, dry-heat, hot-water), was designed to analyze seed germination patterns and dormancy processes. The. results obtained are in agreement with the ecology of the two species. Seeds are not dormant after collection and maintain high viability when preserved by standard seed bank conservation protocols. It was found out that optimal temperature for germination is 20 degrees C for both species. Light seems to play a key role in the germination of genus Sideritis, particularly for S. chamaedryfolia, significantly inhibited by light as other psammophilous plants. Temperature and light arc relevant environmental indicators, but it was found out that the germination response to these factors in the studied species is correlated with a different environmental factor, namely the availability of water resources in their habitats, which is generally a major constraint factor for seed germination in Mediterranean areas. The results indicate that germination limitations are not so much related to taxonomic position, but rather adaptations to water restrictions.This research were cofunded by the Generalitat Valenciana (Conselleria de Territory i Habitatge) and the European Commission, through the Projects LIFE Conservacion de Habitats Prioritarios (LIFE 99 This research were co-funded by the Generalitat Valenciana (Conselleria de Territory i Habitatge) and the European Commission, through the Projects LIFE Conservacion de Habitats Prioritarios (LIFE 99 NAT/E/006417) and Gestión y Puesta en Valor de Tres Hábitats de Alta Montaña (LIFE 03 NAT/E/000064). We thank both institutions, as well as to the University of Valencia for their support to the activities of our research group.) and Gestión y Puesta en Valor de Tres Hábitats de Alta Montaña (LIFE 03 NAT/E/000064). We thank both institutions, as well as to the University of Valencia for their support to the activities of our research group.Estrelles, E.; Güemes, J.; Riera, J.; Boscaiu, M.; Ibars Almonacil, A.; Costa Talens, M. (2010). Seed Germination Behaviour in Sideritis from Different Iberian Habitats. Notulae Botanicae Horti Agrobotanici Cluj-Napoca. 38(1):9-13. https://doi.org/10.15835/nbha3814620S91338

El flujo óptico como herramienta para el vídeo-análisis de fenómenos físicos

[EN] The optical flow analysis is presented as a useful tool to characterize the movement of a body in an automatic way using a digital video. This technique allows to substitute a complex experimental set-up by a video recording system, which is easily available since the large development in the last years of the multi-media systems. Some results obtained from the analysis of different experiments are shown and the possible use of this kind of technique in a teaching laboratory is discussed.[ES] En este artículo se presenta el análisis del flujo óptico como una herramienta que permite caracterizar el movimiento de un cuerpo de forma automática a partir del análisis de un vídeo digital. Esto permite sustituir un montaje experimental complejo por un sistema de grabación de vídeos que, tras el gran desarrollo experimentado por los sistemas multimedia en los últimos años, resulta mucho más asequible. Se muestran los resultados obtenidos en el análisis de distintos experimentos y se comenta su posible utilización en un laboratorio docente.Hueso, JL.; Riera, J.; Ginestar, D. (2013). El flujo óptico como herramienta para el vídeo-análisis de fenómenos físicos. Modelling in Science Education and Learning. 6(1):97-111. doi:10.4995/msel.2013.1843SWORD971116