2,290 research outputs found
Design and implementation of an ultrasonic sensor for rapid monitoring of industrial malolactic fermentation of wines
Ultrasound is an emerging technology that can be applied to monitor food processes. However, ultrasonic techniques are usually limited to research activities within a laboratory environment and they are not extensively used in industrial processes. The aim of this paper is to describe a novel ultrasonic sensor designed to monitor physical–chemical changes that occur in wines stored in industrial tanks. Essentially, the sensor consists of an ultrasonic transducer in contact with a buffer rod, mounted inside a stainless steel tube section. This structure allows the ultrasonic sensor to be directly installed in stainless steel tanks of an industrial plant. The operating principle of this design is based on the measurement of ultrasonic velocity of propagation. To test its proper operation, the sensor has been used to measure changes of concentration in aqueous samples and to monitor the progress of a malolactic fermentation of red wines in various commercial wineries. Results show the feasibility of using this sensor for monitoring malolactic fermentations in red wines placed in industrial tanks.Postprint (author's final draft
A Study of the Transient Response of Duct Junctions: Measurements and Gas-Dynamic Modeling with a Staggered Mesh Finite Volume Approach
[EN] Duct junctions play a major role in the operation and design of most piping systems. The objective of this paper is to establish the potential of a staggered mesh finite volume model as a way to improve the description of the effect of simple duct junctions on an otherwise one-dimensional flow system, such as the intake or exhaust of an internal combustion engine. Specific experiments have been performed in which different junctions have been characterized as a multi-port, and that have provided precise and reliable results on the propagation of pressure pulses across junctions. The results obtained have been compared to simulations performed with a staggered mesh finite volume method with different flux limiters and different meshes and, as a reference, have also been compared with the results of a more conventional pressure loss- based model. The results indicate that the staggered mesh finite volume model provides a closer description of wave dynamics, even if further work is needed to establish the optimal calculation settings.Manuel Hernandez is partially supported through contract FPI-S2-2015-1064 of Programa de Apoyo para la Investigacin y Desarrollo (PAID) of Universitat Politecnica de Valencia.Torregrosa, AJ.; Broatch, A.; García-Cuevas González, LM.; Hernández-Marco, M. (2017). A Study of the Transient Response of Duct Junctions: Measurements and Gas-Dynamic Modeling with a Staggered Mesh Finite Volume Approach. Applied Sciences. 7(5):1-25. https://doi.org/10.3390/app7050480S12575Payri, F., Reyes, E., & Galindo, J. (2000). Analysis and Modeling of the Fluid-Dynamic Effects in Branched Exhaust Junctions of ICE. Journal of Engineering for Gas Turbines and Power, 123(1), 197-203. doi:10.1115/1.1339988Tang, S. K. (2004). Sound transmission characteristics of Tee-junctions and the associated length corrections. The Journal of the Acoustical Society of America, 115(1), 218-227. doi:10.1121/1.1631830Harrison, M. F., De Soto, I., & Rubio Unzueta, P. L. (2004). A linear acoustic model for multi-cylinder IC engine intake manifolds including the effects of the intake throttle. Journal of Sound and Vibration, 278(4-5), 975-1011. doi:10.1016/j.jsv.2003.12.009Karlsson, M., & Åbom, M. (2011). Quasi-steady model of the acoustic scattering properties of a T-junction. Journal of Sound and Vibration, 330(21), 5131-5137. doi:10.1016/j.jsv.2011.05.012Karlsson, M., & Åbom, M. (2010). Aeroacoustics of T-junctions—An experimental investigation. Journal of Sound and Vibration, 329(10), 1793-1808. doi:10.1016/j.jsv.2009.11.024Corberán, J. M. (1992). A New Constant Pressure Model for N-Branch Junctions. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 206(2), 117-123. doi:10.1243/pime_proc_1992_206_167_02Schmandt, B., & Herwig, H. (2015). The head change coefficient for branched flows: Why «losses» due to junctions can be negative. International Journal of Heat and Fluid Flow, 54, 268-275. doi:10.1016/j.ijheatfluidflow.2015.06.004Shaw, C. T., Lee, D. J., Richardson, S. H., & Pierson, S. (2000). Modelling the Effect of Plenum-Runner Interface Geometry on the Flow Through an Inlet System. SAE Technical Paper Series. doi:10.4271/2000-01-0569Pérez-García, J., Sanmiguel-Rojas, E., Hernández-Grau, J., & Viedma, A. (2006). Numerical and experimental investigations on internal compressible flow at T-type junctions. Experimental Thermal and Fluid Science, 31(1), 61-74. doi:10.1016/j.expthermflusci.2006.02.001Naeimi, H., Domiry, G., Gorji, M., Javadirad, G., & Keshavarz, M. (2011). A parametric design of compact exhaust manifold junction in heavy duty diesel engine using CFD. Thermal Science, 15(4), 1023-1033. doi:10.2298/tsci100417041nSakowitz, A., Mihaescu, M., & Fuchs, L. (2014). Turbulent flow mechanisms in mixing T-junctions by Large Eddy Simulations. International Journal of Heat and Fluid Flow, 45, 135-146. doi:10.1016/j.ijheatfluidflow.2013.06.014Bassett, M. D., Winterbone, D. E., & Pearson, R. J. (2001). Calculation of steady flow pressure loss coefficients for pipe junctions. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 215(8), 861-881. doi:10.1177/095440620121500801Hager, W. H. (1984). An Approximate Treatment of Flow in Branches and Bends. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 198(1), 63-69. doi:10.1243/pime_proc_1984_198_088_02Paul, J., Selamet, A., Miazgowicz, K. D., & Tallio, K. V. (2007). Combining Flow Losses at Circular T-Junctions Representative of Intake Plenum and Primary Runner Interface. SAE Technical Paper Series. doi:10.4271/2007-01-0649Pérez-García, J., Sanmiguel-Rojas, E., & Viedma, A. (2010). New coefficient to characterize energy losses in compressible flow at T-junctions. Applied Mathematical Modelling, 34(12), 4289-4305. doi:10.1016/j.apm.2010.05.005Wang, W., Lu, Z., Deng, K., & Qu, S. (2014). An experimental study of compressible combining flow at 45° T-junctions. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 229(9), 1600-1610. doi:10.1177/0954406214546678Peters, B., & Gosman, A. D. (1993). Numerical Simulation of Unsteady Flow in Engine Intake Manifolds. SAE Technical Paper Series. doi:10.4271/930609Bingham, J. F., & Blair, G. P. (1985). An Improved Branched Pipe Model for Multi-Cylinder Automotive Engine Calculations. Proceedings of the Institution of Mechanical Engineers, Part D: Transport Engineering, 199(1), 65-77. doi:10.1243/pime_proc_1985_199_140_01William-Louis, M. J. P., Ould-El-Hadrami, A., & Tournier, C. (1998). On the calculation of the unsteady compressible flow through an N-branch junction. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 212(1), 49-56. doi:10.1243/0954406981521033Bassett, M. D., Pearson, R. J., Fleming, N. P., & Winterbone, D. E. (2003). A Multi-Pipe Junction Model for One-Dimensional Gas-Dynamic Simulations. SAE Technical Paper Series. doi:10.4271/2003-01-0370Pearson, R. J., Bassett, M. D., Batten, P., Winterbone, D. E., & Weaver, N. W. E. (1999). Multi-Dimensional Wave Propagation in Pipe Junctions. SAE Technical Paper Series. doi:10.4271/1999-01-1186Bassett, M. D., Winterbone, D. E., & Pearson, R. J. (2000). Modelling Engines with Pulse Converted Exhaust Manifolds Using One-Dimensional Techniques. SAE Technical Paper Series. doi:10.4271/2000-01-0290Montenegro, G., Onorati, A., Piscaglia, F., & D’Errico, G. (2007). Integrated 1D-MultiD Fluid Dynamic Models for the Simulation of I.C.E. Intake and Exhaust Systems. SAE Technical Paper Series. doi:10.4271/2007-01-0495Onorati, A., Montenegro, G., D’Errico, G., & Piscaglia, F. (2010). Integrated 1D-3D Fluid Dynamic Simulation of a Turbocharged Diesel Engine with Complete Intake and Exhaust Systems. SAE Technical Paper Series. doi:10.4271/2010-01-1194Montenegro, G., Onorati, A., & Della Torre, A. (2013). The prediction of silencer acoustical performances by 1D, 1D–3D and quasi-3D non-linear approaches. Computers & Fluids, 71, 208-223. doi:10.1016/j.compfluid.2012.10.016Morel, T., Silvestri, J., Goerg, K.-A., & Jebasinski, R. (1999). Modeling of Engine Exhaust Acoustics. SAE Technical Paper Series. doi:10.4271/1999-01-1665Sapsford, S. M., Richards, V. C. M., Amlee, D. R., Morel, T., & Chappell, M. T. (1992). Exhaust System Evaluation and Design by Non-Linear Modeling. SAE Technical Paper Series. doi:10.4271/920686Montenegro, G., Della Torre, A., Onorati, A., Fairbrother, R., & Dolinar, A. (2011). Development and Application of 3D Generic Cells to the Acoustic Modelling of Exhaust Systems. SAE Technical Paper Series. doi:10.4271/2011-01-1526Payri, F., Desantes, J. M., & Broatch, A. (2000). Modified impulse method for the measurement of the frequency response of acoustic filters to weakly nonlinear transient excitations. The Journal of the Acoustical Society of America, 107(2), 731-738. doi:10.1121/1.428256Torregrosa, A. J., Broatch, A., Fernández, T., & Denia, F. D. (2006). Description and measurement of the acoustic characteristics of two-tailpipe mufflers. The Journal of the Acoustical Society of America, 119(2), 723. doi:10.1121/1.2159228Torregrosa, A. J., Broatch, A., Arnau, F. J., & Hernández, M. (2016). A non-linear quasi-3D model with Flux-Corrected-Transport for engine gas-exchange modelling. Journal of Computational and Applied Mathematics, 291, 103-111. doi:10.1016/j.cam.2015.03.034Montenegro, G., Della Torre, A., Onorati, A., & Fairbrother, R. (2013). A Nonlinear Quasi-3D Approach for the Modeling of Mufflers with Perforated Elements and Sound-Absorbing Material. Advances in Acoustics and Vibration, 2013, 1-10. doi:10.1155/2013/546120CMT—Motores Térmicos, Universitat Politècnica de Valènciahttp://www.openwam.org/Ikeda, T., & Nakagawa, T. (1979). On the SHASTA FCT Algorithm for the Equation ∂ρ ∂t + ∂ ∂x (υ(ρ)ρ) = 0. Mathematics of Computation, 33(148), 1157. doi:10.2307/2006453Toro, E. F., Spruce, M., & Speares, W. (1994). Restoration of the contact surface in the HLL-Riemann solver. Shock Waves, 4(1), 25-34. doi:10.1007/bf01414629Van Leer, B. (1979). Towards the ultimate conservative difference scheme. V. A second-order sequel to Godunov’s method. Journal of Computational Physics, 32(1), 101-136. doi:10.1016/0021-9991(79)90145-
Crystallization and melting of bacteria colonies and Brownian Bugs
Motivated by the existence of remarkably ordered cluster arrays of bacteria
colonies growing in Petri dishes and related problems, we study the spontaneous
emergence of clustering and patterns in a simple nonequilibrium system: the
individual-based interacting Brownian bug model. We map this discrete model
into a continuous Langevin equation which is the starting point for our
extensive numerical analyses. For the two-dimensional case we report on the
spontaneous generation of localized clusters of activity as well as a
melting/freezing transition from a disordered or isotropic phase to an ordered
one characterized by hexagonal patterns. We study in detail the analogies and
differences with the well-established Kosterlitz-Thouless-Halperin-Nelson-Young
theory of equilibrium melting, as well as with another competing theory. For
that, we study translational and orientational correlations and perform a
careful defect analysis. We find a non standard one-stage, defect-mediated,
transition whose nature is only partially elucidated.Comment: 13 Figures. 14 pages. Submitted to Phys. Rev.
Using the new technologies in claudication patients: CReTe: Claudication patients and telematic register
Objetivo: Presentamos una aplicación informática para teléfonos móviles ideada para el control de sesiones
de ejercicio domiciliario en claudicantes. Exponemos también nuestros resultados preliminares.
Material y métodos: La aplicación está dise˜nada para teléfonos móviles con sistema operativo Android,
tecnología de geolocalización y conexión de datos. Está conectada a una base de datos codificada que
preserva el secreto médico. Los datos que se recogen de las sesiones de ejercicio son la fecha, la hora de
inicio y de fin, el tiempo dedicado, el número de las paradas realizadas y la velocidad máxima, la
velocidad media global y la velocidad entre paradas. Durante el mes de enero de 2014 se reclutó a
aquellos pacientes que aceptaran el estudio, poseyeran y entendieran un dispositivo móvil Android con
geolocalización y conexión de datos. Los criterios de exclusión del estudio una vez comenzado fueron
progresión hacia isquemia arterial crítica, enfermedad intercurrente grave, fallecimiento y ausencia de
comunicación con el paciente. Se recogieron las principales morbilidades y los resultados de los
cuestionarios de calidad de vida SF36 y EuroQol 5D. Se midió el tiempo de primera consulta y el tiempo
dedicado por semana y paciente durante un seguimiento de 28 días. Se calculó el cumplimiento de las
sesiones con respecto a las sesiones pactadas con cada paciente, con un mínimo de 2 semanales.
Resultados: Un total de 5 pacientes fueron incluidos, con edad media de 59,3 a˜nos (mediana 52; rango
40-80). De ellos 2 se excluyeron, uno por progresión a isquemia crítica y otro por ausencia de
comunicación. El tiempo medio dedicado por consulta nueva fue de 29,1 min (mediana 27,5; rango
45-20). El cumplimiento de las sesiones fue del 100% en 2 pacientes y del 63% en otro. El tiempo dedicado
en el seguimiento semanal por paciente fue de 1,68 min.
Conclusiones: CReTe es una herramienta aplicable a nuestro medio que precisa de estudios mayores para
demostrar su utilidad.Objective: The preliminary results are presented on the use of a new application for mobile phones designed to control home exercise sessions in claudication.Materials and methods: The application is designed for Android systems with geolocation tech-nology and Internet connection. It is connected to a database encoded to ensure medical confidentiality. The data collected from the exercise sessions were the date, start time and end time, the time spent, the number of stops made, and the maximum speed, average speed and overall speed between stops. During the month of January 2014 patients who accepted and understood the study, and possessed an Android mobile device with geolocation and data connection, were enrolled. The exclusion criteria, 11 the study started, were progression to arterial ischemia, severe intercurrent illness, non-communication with the patient, and death. Major morbidities and results of quality of life questionnaires SF36 and EuroQol 5 D were collec-ted. Time of first consultation and time spent per week per patient during a 28-day follow-up was recorded. Compliance as regards the agreed sessions was calculated for each patient, with a minimum of 2 weeks.Results: The study included 5 patients with a mean age 59.3 years (median 52; range 40-80). Of these, 2 were excluded, one for progression to critical ischemia and another for non-communication. The average time spent in a new consultation was 29.1 minutes (median 27.5, range 45-20). The compliance with the sessions was 100% in 2 patients, and 63% in another. Time spent in the weekly monitoring per patient was 1.68 minutes.Conclusions: CReTe is an applicable tool in our environment that requires further study to demonstrate its usefulness
Winding number instability in the phase-turbulence regime of the Complex Ginzburg-Landau Equation
We give a statistical characterization of states with nonzero winding number
in the Phase Turbulence (PT) regime of the one-dimensional Complex
Ginzburg-Landau equation. We find that states with winding number larger than a
critical one are unstable, in the sense that they decay to states with smaller
winding number. The transition from Phase to Defect Turbulence is interpreted
as an ergodicity breaking transition which occurs when the range of stable
winding numbers vanishes. Asymptotically stable states which are not
spatio-temporally chaotic are described within the PT regime of nonzero winding
number.Comment: 4 pages,REVTeX, including 4 Figures. Latex (or postscript) version
with figures available at http://formentor.uib.es/~montagne/textos/nupt
Quartz crystal microbalance holder design for on-line sensing in liquid applications
In this paper, the design of a QCM sensor for liquid media measurements in vertical position is described. A rugged and low-cost proof holder has been designed, the cost of which is significantly lower than those of traditional commercial holders. The crystal is not replaceable but it can be easily cleaned. Its small volume permits to be used by dipping it in the liquid with the desired location and orientation. The developed design has been experimentally validated by measuring changes in the resonance frequency and resistance of the QCM sensor immersed vertically in different calibrated aqueous glycerol solutions. The obtained results show a great agreement with the Kanazawa theoretical expression. Consequently, the designed QCM sensor would be appropriate for sensing applications in liquids, and might take part of a future on-line multichannel low-cost QCM-based measurement system.Peer ReviewedPostprint (published version
Multichannel QCM-based system for continuous monitoring of bacterial biofilm growth
© 2020 IEEE. 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.Quartz crystal microbalance (QCM) sensors are becoming a good alternative to analytical methods for the measurement of bacterial growth in liquid media culture. For this purpose, two essential resonance parameters allow monitoring of biofilm formation: the series resonance frequency shift and the change of the resistance at this frequency. Nevertheless, several problems arise in determining these parameters, as their relative variation is very small. This means that an accurate procedure must be implemented for the measurement of the QCM resonance parameters, including the automatic calibration of the frequency response effects of the measurement circuits and the automatic compensation of the static electrical capacitance of the QCM.
In this paper, a novel multichannel system for on-line monitoring of biofilm formation based on QCM sensors is proposed. QCM resonance parameters are determined from the electrical impedance analysis by means of an auto-balanced impedance bridge. This configuration has allowed the implementation of an affordable multichannel measurement instrument. Obtained results, based on binary mixtures of water-glycerol measurements and real microorganism experiments, are in good agreement with the theoretical behaviour. These results show the great potential of this instrument to be used for monitoring microbial growth and biofilm formation.Peer ReviewedPostprint (author's final draft
Your Teammate Just Sent You a New Message! The Effects of Using Telegram on Individual Acquisition of Teamwork Competence
Students’ acquisition of teamwork competence has become a priority for educational institutions. The development of teamwork competence in education generally relies in project-based learning methodologies and challenges. The assessment of teamwork in project-based learning involves, among others, assessing students’ participation and the interactions between team members. Project-based learning can easily be handled in small-size courses, but course management and teamwork assessment become a burdensome task for instructors as the size of the class increases. Additionally, when project-based learning happens in a virtual space, such as online learning, interactions occur in a less natural way. This study explores the use of instant messaging apps (more precisely, the use of Telegram) as team communication space in project-based learning, using a learning analytics tool to extract and analyze student interactions. Further, the study compares student interactions (e.g., number of messages exchanged) and individual teamwork competence acquisition between traditional asynchronous (e.g., LMS message boards) and synchronous instant messaging communication environments. The results show a preference of students for IM tools and increased participation in the course. However, the analysis does not find significant improvement in the acquisition of individual teamwork competence
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