Alfonso Blanco

High-power ultrasonic system for the enhancement of mass transfer in supercritical CO2 extraction processes

Oil is an important component of almonds and other vegetable substrates that can show an influence on human health. In this work the development and validation of an innovative, robust, stable, reliable and efficient ultrasonic system at pilot scale to assist supercritical CO(2) extraction of oils from different substrates is presented. In the extraction procedure ultrasonic energy represents an efficient way of producing deep agitation enhancing mass transfer processes because of some mechanisms (radiation pressure, streaming, agitation, high amplitude vibrations, etc.). A previous work to this research pointed out the feasibility of integrating an ultrasonic field inside a supercritical extractor without losing a significant volume fraction. This pioneer method enabled to accelerate mass transfer and then, improving supercritical extraction times. To commercially develop the new procedure fulfilling industrial requirements, a new configuration device has been designed, implemented, tested and successfully validated for supercritical fluid extraction of oil from different vegetable substrates.

Ultrasonic system for continuous washing of textiles in liquid layers

The use of ultrasonic energy for washing of textiles has been tried several times without achieving practical development. In fact, the softness of the fibres makes the cavitation to produce small erosion effect and the reticulate structure of the fabric favours the formation of air bubble layers which obstruct wave penetration. In addition, a high proportion of water with respect to the wash load and a certain water degassing is required to assure efficiency and homogeneity in the wash performance. Such requirements have hindered the commercial development of the ultrasonic washing machines for domestic purposes. For specific industrial applications, a great part of these limitations may be overcome. This article deals with a new process in which the fabric is exposed to the ultrasonic field in a flat format. Such process has been implemented at laboratory and at semi-industrial stage by using specially designed power ultrasonic transducers with rectangular plate radiators. The cleaning effect is produced by the intense cavitation field generated by the plate radiator within a thin layer of liquid where the fabric is introduced. The homogeneity of such effect is achieved by the successive exposure of all the fabric areas to the intense acoustic field. In this paper the structure and performance of the developed system are shown.

Modal interactions in ultrasonic plate transducers for industrial applications

Among the green technologies that are currently investigated in industry, power ultrasound constitutes an emerging one with a good potential to produce and/or enhance a variety of processes. Lately, a series of power ultrasound systems for applications in the food industry, environment and manufacturing have been developed at laboratory and semi-industrial scales. In order to scale up these systems and their associated processes, elimination and/or control of detrimental modal couplings between tuned and undesired modes are necessary. In this study, the vibration behaviour of a tuned system for defoaming made up of a sandwich transducer of the Langevin-type driving an amplitude concentrator attached to a circular radiating plate was experimentally investigated. A three-mode interaction affecting the performance of the studied power ultrasound system was detected, characterized and classified. The information gathered through this study may be useful for the development of more efficient ultrasonic devices and processes.

A Framework for Acquiring and Analyzing Traces from Cryptographic Devices

We present a Side-Channel Analysis Platform (SCAP) Framework developed to acquire and study the traces derived from a cryptographic device when cryptographic computations are done. The main goal of this work is to develop a tool for performing side-channel attacks against these cryptographic devices. The characteristics of the SCAP Framework are described and a case study with a smartphone is presented.

Description of an ultrasonic technology for food dehydration process intensification

Food dehydration processes assisted by power ultrasound constitute an efficient and green technology. In order to obtain good results with this technology it is necessary to take into account several aspects regarding the ultrasonic generation by a power ultrasonic transducer, the energy propagation in the fluid media and absorption in the samples. Ultrasonic waves produce different effects when propagating through a medium, like an increase in mass transport kinetics, and others related to the so called sponge effect and cavitation. This kind of process needs the whole system to work in a power regime. This may imply the appearance of non-linear effects in the transducer behavior and in the acoustic field generated inside the dehydration chamber. This paper describes this technology, paying special attention to the numerical design and the dynamic and modal characterization of the power ultrasonic transducer. As a conclusion, neither modal interaction nor any other non-linear effect, apart from a slight ...