Francisco Martinez Trujillo - Academia.edu (original) (raw)

Papers by Francisco Martinez Trujillo

Food Engineering Reviews, 2015

The design aspects for building a megasonic reactor for separation of food materials from liquid/... more The design aspects for building a megasonic reactor for separation of food materials from liquid/liquid or solid/liquid mixtures are presented in this review. These aspects are based on the theoretical principles of acoustic particle manipulation such as the acoustic primary and secondary radiation forces, acoustic streaming, and the properties of food materials. Key considerations for the design of megasonic reactors are reviewed, which include the transducer selection, positioning and alignment, as well as construction materials and geometry of transducers and reactor. The design of these reactors is discussed around various food applications including palm oil separation, milk fat separation and fractionation, yeast separation in fermentation processes, and separation of microalgae.

Trends in Food Science & Technology, 2015

Ultrasound treatment is an alternative affordable, effective and reproducible method for the impr... more Ultrasound treatment is an alternative affordable, effective and reproducible method for the improved recovery of bioactive compounds from various processing streams. The objective of this review is to discuss the impact of ultrasound-assisted extraction on the recovery of polyphenols, carotenoids and chlorophylls from vegetal and algae matters. Optimization strategies will need to focus on appropriate equipment design and configuration of ultrasonic components, and extrinsic and intrinsic control parameters including ultrasonic power, temperature and extraction time to maximize the yield and biological activity of the extract. Modeling strategies to characterize and optimize ultrasound processes are also be highlighted in the manuscript.

When a wireless node in an ad hoc network needs Internet access, it must select one gateway from ... more When a wireless node in an ad hoc network needs Internet access, it must select one gateway from the information sent in the Modified Router Advertisement (MRA) messages. In this paper, we propose an adaptive gateway discovery scheme that dynamically adjusts the frequency of MRA messages. This tuning is related to the mobility of the ad hoc network. The proposed

An adaptive genetic fuzzy control gateway discovery to interconnect hybrid MANETs ... AbstractIn... more An adaptive genetic fuzzy control gateway discovery to interconnect hybrid MANETs ... AbstractIn wireless communication, Mobile Ad Hoc NETwork (MANET) is a set of mobile nodes that are dynamically and randomly located in such a manner that the wireless link among ...

Page 1. A. Özcan, N. Chaki, and D. Nagamalai (Eds.): WiMo 2010, CCIS 84, pp. 273282, 2010. © Spr... more Page 1. A. Özcan, N. Chaki, and D. Nagamalai (Eds.): WiMo 2010, CCIS 84, pp. 273282, 2010. © Springer-Verlag Berlin Heidelberg 2010 An Optimized MANET Gateway Discovery Based on Fuzzy Logic Antonio J. Yuste1, Alicia ...

Food Engineering Reviews, 2014

Innovative food processing technologies, such as high-pressure (low and high temperature), pulsed... more Innovative food processing technologies, such as high-pressure (low and high temperature), pulsed electric field and ultrasound processing, can be applied to manufacture safe foods with better sensory and nutrition properties. These technologies can play an important role towards satisfying consumer demand for safe and innovative products, while reducing the carbon and water footprint, to promote more sustainable food manufacturing. The design, application and optimisation of suitable equipment and the selection of process conditions for these technologies require further knowledge development. Computational fluid dynamics has been established as a tool for characterising, improving and optimising traditional food processing technologies. Innovative technologies, however, provide additional complexity and challenges because of the interacting Multiphysics phenomena. This review will highlight a number of Multiphysics modelling case studies for the characterisation of various processing aspects and optimisation of selected innovative technologies. The underlying inactivation mechanisms, efficiencies and design limitations of these technologies are currently still under investigation and will be discussed.

Knoerzer/Innovative Food Processing Technologies: Advances in Multiphysics Simulation, 2011

Proceedings of the 5th ACM international workshop on Mobility management and wireless access - MobiWac '07, 2007

Page 1. An Adaptive Gateway Discovery for Mobile Ad Hoc Networks AJ Yuste Department of Telecommu... more Page 1. An Adaptive Gateway Discovery for Mobile Ad Hoc Networks AJ Yuste Department of Telecommunication Engineering University of Jaen Alfonso X El Sabio, 10 23700 Linares, Spain Phone: 34 953 64 85 43 ajyuste@ujaen.es ...

Wireless Systems and Mobility in Next Generation Internet, 2008

The integration of mobile ad hoc networks into IP-based access networks demands the presence of a... more The integration of mobile ad hoc networks into IP-based access networks demands the presence of a gateway which is responsible for propagating some configuration parameters by means of Modified Router Advertisement (MRA) messages. This function may be accomplished on demand by the mobile nodes (reactively), periodically activated by the gateway (proactively) or by combining the two approaches. In the proactive mechanisms, the interval of emission of the MRA messages (T) may significantly affect the network performance. The optimum value for T depends on the network conditions such as the position of the sources, the mobility of nodes, etc. Therefore, an autonomous and adaptive technique to dynamically configure T is strongly recommended. In this sense, a new adaptive gateway discovery mechanism is proposed in this paper. The adaptation is achieved by a control system which has been conveniently configured by means of an analytical model. Simulation results show that the proposed adaptive mechanism improves the conventional proactive schemes.

2010 IEEE 30th International Conference on Distributed Computing Systems Workshops, 2010

This paper presents an adaptive scheme for gateway discovery in MANETs connected to the Internet.... more This paper presents an adaptive scheme for gateway discovery in MANETs connected to the Internet. Basically, the proposed scheme reduces the flooding processes related to gateway discovery. To do so, the algorithm dynamically adjusts the interval of emission of the gateway advertisement messages to the need for updated routes to the gateway. The tuning is supported by the analysis of the spatial distribution of nodes in the MANET and by the impact that the relative position of nodes has on the route lifetimes. The simulations show that the proposed adaptive mechanism outperforms the conventional schemes: it decreases network saturation while it achieves lower end-to-end delay and it minimizes the routing overhead.

International Journal of Wireless & Mobile Networks, 2010

In order to extend the use of Mobile ad hoc networks (MANET) to commercial applications, it is ne... more In order to extend the use of Mobile ad hoc networks (MANET) to commercial applications, it is necessary to provide a mechanism to integrate this kind of networks into the Internet. In this way, MANETs could be utilized in visiting theme parks, commercial centers and military scenarios. The interconnection of MANETs and the Internet is supported by a Gateway. The gateway is responsible for informing about some configuration parameters as well as for enabling the creation of the routes to the Internet in the MANET nodes. For these tasks, several control messages are generated. The method in which these messages are originated defines the existing Integration Supports for MANETs. In particular, under the hybrid Global Connectivity support, the Gateway generates periodic Modified Router Advertisements (MRA) which are broadcast in an area close to the Gateway. The optimum values to define the periodicity of these messages and the diameter (number of hops) of the area in which they are propagated depend on the network conditions. Therefore, an automatic and dynamic algorithm is recommended to be implemented in the Gateway to adjust these two parameters. In this sense, this paper presents a technique by which the interval of emission of the MRA messages is controlled by a fuzzy system. The fuzzy system captures several network conditions such as the link stability or the number of sources. The simulation results show that the proposed scheme outperforms other adaptive approaches for the gateway discovery in MANETs.

Avances en Diabetología, 2012

Resumen La insulina aspart aporta una serie de ventajas en su farmacocinetica y farmacodinamia qu... more Resumen La insulina aspart aporta una serie de ventajas en su farmacocinetica y farmacodinamia que la hacen una opcion muy atractiva para su empleo en los pacientes de edad avanzada. La edad avanzada per se es uno de los factores que favorecen las hipoglucemias en el paciente insulinizado. Otros factores diferenciadores de la poblacion anciana diabetica insulinizada son: la polimedicacion y el deterioro de la funcion renal y del nivel cognitivo.

Ultrasonics Sonochemistry, 2013

A model was developed to determine the local changes of concentration of particles and the format... more A model was developed to determine the local changes of concentration of particles and the formations of bands induced by a standing acoustic wave field subjected to a sawtooth frequency ramping pattern. The mass transport equation was modified to incorporate the effect of acoustic forces on the concentration of particles. This was achieved by balancing the forces acting on particles. The frequency ramping was implemented as a parametric sweep for the time harmonic frequency response in time steps of 0.1 s. The physics phenomena of piezoelectricity, acoustic fields and diffusion of particles were coupled and solved in COMSOL Multiphysics™ (COMSOL AB, Stockholm, Sweden) following a three step approach. The first step solves the governing partial differential equations describing the acoustic field by assuming that the pressure field achieves a pseudo steady state. In the second step, the acoustic radiation force is calculated from the pressure field. The final step allows calculating the locally changing concentration of particles as a function of time by solving the modified equation of particle transport. The diffusivity was calculated as function of concentration following the Garg and Ruthven [1] equation which describes the steep increase of diffusivity when the concentration approaches saturation. However, it was found that this steep increase creates numerical instabilities at high voltages (in the piezoelectricity equations) and high initial particle concentration. The model was simplified to a pseudo one-dimensional case due to computation power limitations. The predicted particle distribution calculated with the model is in good agreement with the experimental data as it follows accurately the movement of the bands in the centre of the chamber.

Ultrasonics Sonochemistry, 2011

High power ultrasound reactors have gained a lot of interest in the food industry given the effec... more High power ultrasound reactors have gained a lot of interest in the food industry given the effects that can arise from ultrasonic-induced cavitation in liquid foods. However, most of the new food processing developments have been based on empirical approaches. Thus, there is a need for mathematical models which help to understand, optimize, and scale up ultrasonic reactors. In this work, a computational fluid dynamics (CFD) model was developed to predict the acoustic streaming and induced heat generated by an ultrasonic horn reactor. In the model it is assumed that the horn tip is a fluid inlet, where a turbulent jet flow is injected into the vessel. The hydrodynamic momentum rate of the incoming jet is assumed to be equal to the total acoustic momentum rate emitted by the acoustic power source. CFD velocity predictions show excellent agreement with the experimental data for power densities higher than W 0 /V P 25 kW m À3. This model successfully describes hydrodynamic fields (streaming) generated by low-frequency-high-power ultrasound.

Journal of Solar Energy Engineering, 2006

A new externally irradiated photoreactor configuration combining the excellent mass transfer char... more A new externally irradiated photoreactor configuration combining the excellent mass transfer characteristics of a bubble column operation with the separation power of an immobilized catalyst on quartz plates has been investigated using computational fluid dynamics (CFD) simulation. The radiative transport equation (RTE) in conjunction with the Navier-Stokes equations were solved to obtain the light incident radiative flux and the light absorbed by the immobilized titania as a function of the gas superficial velocity, the angle of inclination, and the separating distance between the plates. The model employed water and air as the fluid phases and the results indicated that gas bubbling considerably increased the incident radiation in the gas-liquid mixture enhancing the radiative flux and the absorbed radiation on the titania-coated plates. The CFD results pave the way for the optimization of a solar photocatalytic reactor for the degradation of organic pollutants.

Journal of Food Engineering, 2007

The diffusivity of water in meat perpendicular to the fibres was experimentally determined in the... more The diffusivity of water in meat perpendicular to the fibres was experimentally determined in the range 6.6–40.4°C using a drying technique. Three different mathematical methods were used to determine the diffusivity from the drying data. The first assumes constant diffusivity, volume and temperature and zero surface resistance to mass transfer. The second assumes a convective boundary condition. The third also

International Journal of Refrigeration, 2003

... Modélisation du refroidissement des cuisses, de l'aloyau et de l'épaule de buf à l... more ... Modélisation du refroidissement des cuisses, de l'aloyau et de l'épaule de buf à l'aide d'une méthode évolutive. FJ Trujillo Corresponding Author Contact Information and QT Pham. Department of Chemical Engineering, University of New South Wales, Sydney 2052, Australia. ...

International Journal of Refrigeration, 2009

A multilayer two-dimensional model of beef carcass chilling using CFD-generated heat transfer coe... more A multilayer two-dimensional model of beef carcass chilling using CFD-generated heat transfer coefficients was used to calculate the parameters of leg and shoulder cooling curves, assuming an exponential cooling model. A central composite experiment was designed to systematically vary air velocity, side weight and fat thickness. Comparison with experimental data suggests that the predicted characteristic time for the leg, and hence the cooling time to a given temperature, should be multiplied by a correction factor 1.07. The effects of airflow direction and of radiation heat transfer have been quantified. A correlation was proposed to estimate leg centre temperature from shoulder temperature. The shortcut formulae and methods presented here will be useful in the design and troubleshooting of industrial beef chillers. They could also be used in Monte Carlo simulations where a large number of samples are considered, to take into account random variations in product characteristics and operating conditions.

International Journal of Refrigeration, 2006

LIST OF PUBLICATIONS III ACKNOWLEGEMENTS IV TABLE OF CONTENTS V NOMENCLATURE_____________________... more LIST OF PUBLICATIONS III ACKNOWLEGEMENTS IV TABLE OF CONTENTS V NOMENCLATURE__________________________________________ XII X 9.4 CFD modelling of heat and moisture transfer on a two-dimensional model of a beef leg 9.5 3D model of beef carcasses and steady state simulation 246 9.6 CFD modelling of heat and moisture transfer on a full 3D model of beef carcasses REFERENCES Al. FINITE VOLUME VBA SUB ROUTINE OF WATER