La cultura del ocio y su función de cambio social hacia el final del siglo XX.

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Improvement of water transport mechanisms during potato drying by applying ultrasound

Background: The drying rate of vegetables is limited by internal moisture diffusion and convective transport mechanisms. The increase of drying air temperature leads to faster water mobility; however, it provokes quality loss in the product and presents a higher energy demand. Therefore, the search for new strategies to improve water mobility during convective drying constitutes a topic of relevant research. The aim of this work was to evaluate the use of power ultrasound to improve convective drying of potato and quantify the influence of the applied power in the water transport mechanisms. Results: Drying kinetics of potato cubes were increased by the ultrasonic application. The influence of power ultrasound was dependent on the ultrasonic power (from 0 to 37 kW m -3), the higher the applied power, the faster the drying kinetic. The diffusion model considering external resistance to mass transfer provided a good fit of drying kinetics. From modelling, it was observed a proportional and significant (P < 0.05) influence of the applied ultrasonic power on the identified kinetic parameters: effective moisture diffusivity and mass transfer coefficient. Conclusions: The ultrasonic application during drying represents an interesting alternative to traditional convective drying by shortening drying time, which may involve an energy saving concerning industrial applications. In addition, the ultrasonic effect in the water transport is based on mechanical phenomena with a low heating capacity, which is highly relevant for drying heat sensitive materials and also for obtaining high-quality dry products. © 2011 Society of Chemical Industry.The authors acknowledge the Ministerio de Ciencia e Innovacion for financial support from the project DPI2009-14549-C04-04.Ozuna López, C.; Carcel Carrión, JA.; García Pérez, JV.; Mulet Pons, A. (2011). Improvement of water transport mechanisms during potato drying by applying ultrasound. Journal of the Science of Food and Agriculture. 91(14):2511-2517. doi:10.1002/jsfa.4344S251125179114Ertekin, C., & Yaldiz, O. (2004). Drying of eggplant and selection of a suitable thin layer drying model. Journal of Food Engineering, 63(3), 349-359. doi:10.1016/j.jfoodeng.2003.08.007Hernández, J. A., Pavón, G., & Garcı́a, M. A. (2000). Analytical solution of mass transfer equation considering shrinkage for modeling food-drying kinetics. Journal of Food Engineering, 45(1), 1-10. doi:10.1016/s0260-8774(00)00033-9Simal, S., Femenia, A., Garcia-Pascual, P., & Rosselló, C. (2003). Simulation of the drying curves of a meat-based product: effect of the external resistance to mass transfer. Journal of Food Engineering, 58(2), 193-199. doi:10.1016/s0260-8774(02)00369-2Mulet, A., Blasco, M., García-Reverter, J., & García-Pérez, J. (2005). Drying Kinetics ofCurcuma longaRhizomes. Journal of Food Science, 70(5), E318-E323. doi:10.1111/j.1365-2621.2005.tb09971.xDe la Fuente-Blanco, S., Riera-Franco de Sarabia, E., Acosta-Aparicio, V. M., Blanco-Blanco, A., & Gallego-Juárez, J. A. (2006). Food drying process by power ultrasound. Ultrasonics, 44, e523-e527. doi:10.1016/j.ultras.2006.05.181García-Pérez, J. V., Cárcel, J. A., de la Fuente-Blanco, S., & Riera-Franco de Sarabia, E. (2006). Ultrasonic drying of foodstuff in a fluidized bed: Parametric study. Ultrasonics, 44, e539-e543. doi:10.1016/j.ultras.2006.06.059Cárcel, J. A., García-Pérez, J. V., Riera, E., & Mulet, A. (2007). Influence of High-Intensity Ultrasound on Drying Kinetics of Persimmon. Drying Technology, 25(1), 185-193. doi:10.1080/07373930601161070García-Pérez, J. V., Cárcel, J. A., Riera, E., & Mulet, A. (2009). Influence of the Applied Acoustic Energy on the Drying of Carrots and Lemon Peel. Drying Technology, 27(2), 281-287. doi:10.1080/07373930802606428Gallego-Juarez, J. A. (2010). High-power ultrasonic processing: Recent developments and prospective advances. Physics Procedia, 3(1), 35-47. doi:10.1016/j.phpro.2010.01.006Mulet, A., Cárcel, J. A., Sanjuán, N., & Bon, J. (2003). New Food Drying Technologies - Use of Ultrasound. Food Science and Technology International, 9(3), 215-221. doi:10.1177/1082013203034641Gallego-Juarez, J. A., Rodriguez-Corral, G., Gálvez Moraleda, J. C., & Yang, T. S. (1999). A NEW HIGH-INTENSITY ULTRASONIC TECHNOLOGY FOR FOOD DEHYDRATION. Drying Technology, 17(3), 597-608. doi:10.1080/07373939908917555Gallego-Juárez, J. A., Rodriguez, G., Acosta, V., & Riera, E. (2010). Power ultrasonic transducers with extensive radiators for industrial processing. Ultrasonics Sonochemistry, 17(6), 953-964. doi:10.1016/j.ultsonch.2009.11.006DA-MOTA, V. M., & PALAU, E. (1999). ACOUSTIC DRYING OF ONION. Drying Technology, 17(4-5), 855-867. doi:10.1080/07373939908917574C. C. Huxsoll and C. W. Hall. (1970). Effects of Sonic Irradiation on Drying Rates of Wheat and Shelled Corn. Transactions of the ASAE, 13(1), 0021-0024. doi:10.13031/2013.38525Muralidhara, H. S., & Ensminger, D. (1986). ACOUSTIC DRYING OF GREEN RICE. Drying Technology, 4(1), 137-143. doi:10.1080/07373938608916315Ortuño C García-Pérez JV Cárcel JA Femenia A Mulet A Modelling of ultrasonically assisted convective drying of eggplant Proceedings of the 17th International Drying Symposium IDS 2010 2010Cárcel, J. A., Nogueira, R. I., García-Pérez, J. V., Sanjuán, N., & Riera, E. (2010). Ultrasound Effects on the Mass Transfer Processes during Drying Kinetic of Olive Leaves (Olea Europea, var. Serrana). Defect and Diffusion Forum, 297-301, 1083-1090. doi:10.4028/www.scientific.net/ddf.297-301.1083NAKAGAWA, S., YAMASHITA, T., & MIURA, H. (1996). Ultrasonic Drying of Walleye Pollack Surimi. NIPPON SHOKUHIN KAGAKU KOGAKU KAISHI, 43(4), 388-394. doi:10.3136/nskkk.43.388García-Pérez, J. V., Cárcel, J. A., Benedito, J., & Mulet, A. (2007). Power Ultrasound Mass Transfer Enhancement in Food Drying. Food and Bioproducts Processing, 85(3), 247-254. doi:10.1205/fbp07010McMinn, W. A. ., & Magee, T. R. . (2003). Thermodynamic properties of moisture sorption of potato. Journal of Food Engineering, 60(2), 157-165. doi:10.1016/s0260-8774(03)00036-0Garau, M. C., Simal, S., Femenia, A., & Rosselló, C. (2006). Drying of orange skin: drying kinetics modelling and functional properties. Journal of Food Engineering, 75(2), 288-295. doi:10.1016/j.jfoodeng.2005.04.017Ortuño, C., Pérez-Munuera, I., Puig, A., Riera, E., & Garcia-Perez, J. V. (2010). Influence of power ultrasound application on mass transport and microstructure of orange peel during hot air drying. Physics Procedia, 3(1), 153-159. doi:10.1016/j.phpro.2010.01.022Chua, K. J., & Chou, S. K. (2005). A comparative study between intermittent microwave and infrared drying of bioproducts. International Journal of Food Science and Technology, 40(1), 23-39. doi:10.1111/j.1365-2621.2004.00903.xHebbar, H. U., Vishwanathan, K. ., & Ramesh, M. . (2004). Development of combined infrared and hot air dryer for vegetables. Journal of Food Engineering, 65(4), 557-563. doi:10.1016/j.jfoodeng.2004.02.020Mulet, A. (1994). Drying modelling and water diffusivity in carrots and potatoes. Journal of Food Engineering, 22(1-4), 329-348. doi:10.1016/0260-8774(94)90038-8Hassini, L., Azzouz, S., Peczalski, R., & Belghith, A. (2007). Estimation of potato moisture diffusivity from convective drying kinetics with correction for shrinkage. Journal of Food Engineering, 79(1), 47-56. doi:10.1016/j.jfoodeng.2006.01.025Zogzas, N. P., Maroulis, Z. B., & Marinos-Kouris, D. (1994). MOISTURE DEFFUSIVITY METHODS OF EXPERIMENTAL DETERMINATION AREVIEW. Drying Technology, 12(3), 483-515. doi:10.1080/07373939408959975Bon, J., Simal, S., Rosselló, C., & Mulet, A. (1997). Drying characteristics of hemispherical solids. Journal of Food Engineering, 34(2), 109-122. doi:10.1016/s0260-8774(97)00098-8Afzal, T. M., & Abe, T. (1998). Diffusion in potato during far infrared radiation drying. Journal of Food Engineering, 37(4), 353-365. doi:10.1016/s0260-8774(98)00111-3McMinn, W. A. M., Khraisheh, M. A. M., & Magee, T. R. A. (2003). Modelling the mass transfer during convective, microwave and combined microwave-convective drying of solid slabs and cylinders. Food Research International, 36(9-10), 977-983. doi:10.1016/s0963-9969(03)00118-2Gallego-Juárez, J. A., Riera, E., de la Fuente Blanco, S., Rodríguez-Corral, G., Acosta-Aparicio, V. M., & Blanco, A. (2007). Application of High-Power Ultrasound for Dehydration of Vegetables: Processes and Devices. Drying Technology, 25(11), 1893-1901. doi:10.1080/0737393070167737

Estudio de efectos de asimetría en vibradores ultrasónicos axisimétricos

8 pages, 6 figures.-- Comunicación presentada en: XXXV Congreso Español de Acústica – TecniAcústica 2004, IV Congreso Iberoamericano de Acústica, IV Congreso Ibérico de Acústica y EAA Symposium "Environmental and Architectural Acoustics" (Guimaraes, 14-17 Sep 2004).[EN] The use of high-power ultrasonic plate transducers shows a series of problems related with the presence of modal coupling or interactions between the vibrational modes of the ultrasonic system. In such system, the radiator consists of a stepped circular plate. The radiator plate is driven at its centre by a tuned piezoelectric vibrator generating an axysimetric mode of vibration. Nevertheless, in many cases the nodal figures are deformed and present ovals instead of circles in the plate. This phenomenon which is frequently observed can be basically due to two main reasons: the material anisotropy and the influence of the high-density of nonaxysimetrical modes around the operating frequency.This paper deals with the study and analysis of both possibilities using numerical simulations by finite element techniques and experimental measurements.[ES] El uso de transductores ultrasónicos de potencia del tipo placa vibrante, plantea una serie de problemas relacionados con el posible acoplamiento o interacción entre los diversos modos de vibración que contiene el sistema. En estos transductores el radiador está constituido por una placa vibrante de geometría circular y perfil escalonado. Esta placa se pone en vibración mediante un excitador piezoeléctrico sintonizado a la frecuencia del modo de vibración de interés. La placa radiante se excita sinusoidalmente en su centro generando un modo de vibración axisimétrico. Las figuras nodales que se forman son círculos concéntricos. Sin embargo, en muchos casos aparecen asimetrías en el modo de vibración, de forma que las figuras nodales aparecen deformadas en forma de óvalos. Este fenómeno, que se repite con determinada frecuencia, puede ser debido fundamentalmente a dos causas: la influencia de modos cercanos no axisimétricos o a la anisotropía del material.En este trabajo se estudian y analizan ambas posibilidades empleando tanto técnicas de simulación numérica por elementos finitos como medidas experimentales.Este trabajo ha sido financiado con cargo al Proyecto del Plan Nacional de Investigación DPI 2002-3409.Peer reviewe

A NEW HIGH-INTENSITY ULTRASONIC TECHNOLOGY FOR FOOD DEHYDRATION

12 páginas, 7 figurasAt present, there is a growing interest in the field of dehydration for preserving food. Ultrasonic energy represents a means to obtain dehydration without affecting the food. This paper deals with an experimental study about the use of high-intensity ultrasound for vegetable dehydration by using a new power ultrasound generator and a procedure in which ultrasonic vibrations are applied in direct contact with the product and under a certain static pressure. The drying effect of this new process is compared with that obtained from forced-air drying assisted by air-borne ultrasonic radiation and from a conventional hot-air drying. The results show that by using the new technology and procedure it is possible to reduce dramatically the treatment time and it is relatively easy to reach a final moisture content in the samples less than 1%. In addition, the product qualities are well preserved, the sample rehydration is higher than 70% and, because of the high efficiency of the new ultrasonic system employed, the energy consumption is low. As a consequence of the results a new technology for industrial applications is under development.Peer reviewe

Enfermedad de Parkinson. Últimos avances en el tratamiento

El Parkinson es la segunda enfermedad neurodegenerativa más frecuente, consiste en la destrucción progresiva del tejido dopaminérgico situado en la sustancia negra del sistema nervioso central. Dicha enfermedad afecta gravemente a la calidad de vida de las personas que la padecen y aunque hay numerosos medicamentos dirigidos a su tratamiento, únicamente se ha conseguido disminuir los síntomas que el Parkinson produce pero no curar la enfermedad, además dichos fármacos tienen numerosos efectos secundarios. Por todo ello se continúa con la investigación de nuevos fármacos más eficaces y con menos reacciones adversas

Procedimiento y sistema ultrasónico de desespumación mediante emisores con placa vibrante escalonada

Referencia OEPM: P200202113.-- Fecha de solicitud: 13/09/2002.-- Titular: Consejo Superior de Investigaciones Científicas (CSIC).Procedimiento y sistema ultrasónico de desespumación mediante emisores con placa vibrante escalonada (ver figura en archivo de texto adjunto). El objeto de esta solicitud de patente es un dispositivo ultrasónico que permite eliminar espumas y controlar su crecimiento en grandes contenedores. El dispositivo emplea emisores sónicos y/o ultrasónicos del tipo placa vibrante escalonada, especiales para radiar altas intensidades acústicas en gases, los cuales, al estar libremente suspendidos en un soporte giratorio con rotación variable controlada, generan en su movimiento por acción de la fuerza centrífuga un recorrido complejo de los haces acústicos emitidos que permite barrer la superficie sobre la que se forma la espuma. Por efecto de la alta intensidad acústica ( >170 dB ref. 2.10^-4 μbar) gran parte de las burbujas de la espuma se van rompiendo casi instantáneamente al paso del haz ultrasónico.Peer reviewe

Industrial requirements in high-power ultrasonic transducers for defoaming

Ponencia presentada en el XIX Congreso Internacional de Acústica (ICA2007), Madrid, 2-7 Sep 2007.-- PACS: 43.35.-c.Airborne stepped-plate focusing transducers have shown to be an efficient tool for breaking foams. The main characteristics of such transducers are their high efficiency and power capacity as well as their strong focusing effect. As a consequence, by using these power transducers it is possible to generate intensities in the focal area as high as 170 dB. However, for their application to industrial problems a special design has to be done covering specific requirements. The main requirements for industrial applications refer to efficiency, safety, durability and environmental resistance. This paper deals with the design and characterization of an industrial prototype of high power ultrasonic transducer for defoaming which is able to work in continuous operation under adverse environmental conditions, and high power excitation without the use of any cooling system. In addition, the transducer is designed to ensure the safe use of airborne high-power ultrasound according to the international recommendations for occupational exposure limits.The industrial use of the transducers is for defoaming in bottling and canning lines and in fermenting vessels and other reactors.The work has been carried out in the frame of the Project: “Adaptation to requirements and industrial standards of an ultrasonic system for foam elimination and control, (CSIC Intramural Programme PIE 2004-50E193).Peer reviewe

Automatic real-time monitoring and assessment of tremor parameters in the upper limb from orientation data

Upper limb tremor is the most prevalent movement disorder and, unfortunately, it is not effectively managed in a large proportion of the patients. Neuroprostheses that stimulate the sensorimotor pathways are one of the most promising alternatives although they are still under development. To enrich the interpretation of data recorded during long-term tremor monitoring and to increase the intelligence of tremor suppression neuroprostheses we need to be aware of the context. Context awareness is a major challenge for neuroprostheses and would allow these devices to react more quickly and appropriately to the changing demands of the user and/or task. Traditionally kinematic features are used to extract context information, with most recently the use of joint angles as highly potential features. In this paper we present two algorithms that enable the robust extraction of joint angle and related features to enable long-term continuous monitoring of tremor with context awareness. First, we describe a novel relative sensor placement identification technique based on orientation data. We focus on relative rather than absolute sensor location, because in many medical applications magnetic and inertial measurement units (MIMU) are used in a chain stretching over adjacent segments, or are always placed on a fixed set of locations. Subsequently we demonstrate how tremor parameters can be extracted from orientation data using an adaptive estimation algorithm. Relative sensor location was detected with an accuracy of 94.12% for the 4 MIMU configuration, and 100% for the 3 MIMU configurations. Kinematic tracking error values with an average deviation of 8% demonstrate our ability to estimate tremor from orientation data. The methods presented in this study constitute an important step toward more user-friendly and context-aware neuroprostheses for tremor suppression and monitoring

Model-based investigation into atmospheric freeze drying assisted by power ultrasound

Atmospheric freeze drying consists of a convective drying process using air at a temperature below the freezing point of the processed product, and with a very low relative humidity content. This paper focuses on the use of a simple one-dimensional model considering moving boundary vapor diffusion to describe the ultrasonic assisted atmospheric freeze-drying of foodstuffs. The case study is the drying of apple cubes (8.8 mm) at different air velocities (1, 2, 4 and 6 m/s), temperatures ( 5, 10 and 15 C), without and with (25, 50 and 75 W) power ultrasound application. By fitting the proposed diffusion model to the experimental drying kinetics, the effective diffusivity of water vapor in the dried product was estimated. The model was successfully validated by drying apple samples of different size and geometry (cubes and cylinders). Finally, a 23 factorial design of experiments revealed that the most relevant operating parameter affecting the drying time was the applied ultrasound power level.The authors acknowledge the financial support of the Spanish Ministerio de Economia y Competitividad (MINECO) and of the European Regional Development Fund (ERDF) through the project DPI2012-37466-CO3-03, the FPI fellowship (BES-2010-033460) and the EEBB-I-14-08572 fellowship granted to J.V. Santacatalina for a short stay at Politecnico di Torino.Santacatalina Bonet, JV.; Fissore, D.; Cárcel Carrión, JA.; Mulet Pons, A.; García Pérez, JV. (2015). Model-based investigation into atmospheric freeze drying assisted by power ultrasound. Journal of Food Engineering. 151:7-15. https://doi.org/10.1016/j.jfoodeng.2014.11.013S71515