Importance and Applications of Ultrasonic Technology to Improve Food Quality

Nutritional value and quality of food products are very important for a healthy life of human beings. Various modern thermal and nonthermal application technologies such as pulsed light, pulsed electric field, high and low hydrostatic pressure, microwave, and ohmic heating have been used to improve food products characteristics. In recent years, ultrasonic applications have been used for food processing. The ultrasonic is defined as sound waves with a frequency exceeding the human hearing limit. Based on the frequency range of ultrasonic waves, it can be used in many industrial applications including the processing of food. Applications of high-power ultrasonic with low frequency aim to improve the quality of food products. Low-power ultrasonic with high-frequency applications are used for nondestructive quality evaluation of physicochemical properties of food. The most important advantages of ultrasonic technologies are the low cost of food processing, low power consumption, simplicity compared to other technologies, suitability for the treatment of solid and liquid food, and environmental safeness and friendliness, thus becoming a promising technology for monitoring and improving quality of food products. The main objective of this chapter is to provide an overview of the principal and recent applications of ultrasonic waves to improve food product quality

Ultrasound for Material Characterization and Processing

Ultrasonic waves are nowadays used for multiple purposes including both low-intensity/high frequency and high-intensity/low-frequency ultrasound. Low-intensity ultrasound transmits energy through the medium in order to obtain information about the medium or to convey information through the medium. It is successfully used in non-destructive inspection, ultrasonic dynamic analysis, ultrasonic rheology, ultrasonic spectroscopy of materials, process monitoring, applications in civil engineering, aerospace and geological materials and structures, and in the characterization of biological media. Nowadays, it is an essential tool for assessing metals, plastics, aerospace composites, wood, concrete, and cement. High-intensity ultrasound deliberately affects the propagation medium through the high local temperatures and pressures generated. It is used in industrial processes such as welding, cleaning, emulsification, atomization, etc.; chemical reactions and reactor induced by ultrasonic waves; synthesis of organic and inorganic materials; microstructural effects; heat generation; accelerated material characterization by ultrasonic fatigue testing; food processing; and environmental protection. This book collects eleven papers, one review, and ten research papers with the aim to present recent advances in ultrasonic wave propagation applied for the characterization or the processing of materials. Both fundamental science and applications of ultrasound in the field of material characterization and material processing have been gathered

Laser Ultrasound Inspection Based on Wavelet Transform and Data Clustering for Defect Estimation in Metallic Samples

Laser-generated ultrasound is a modern non-destructive testing technique. It has been investigated over recent years as an alternative to classical ultrasonic methods, mainly in industrial maintenance and quality control procedures. In this study, the detection and reconstruction of internal defects in a metallic sample is performed by means of a time-frequency analysis of ultrasonic waves generated by a laser-induced thermal mechanism. In the proposed methodology, we used wavelet transform due to its multi-resolution time frequency characteristics. In order to isolate and estimate the corresponding time of flight of eventual ultrasonic echoes related to internal defects, a density-based spatial clustering was applied to the resulting time frequency maps. Using the laser scan beam’s position, the ultrasonic transducer’s location and the echoes’ arrival times were determined, the estimation of the defect’s position was carried out afterwards. Finally, clustering algorithms were applied to the resulting geometric solutions from the set of the laser scan points which was proposed to obtain a two-dimensional projection of the defect outline over the scan plane. The study demonstrates that the proposed method of wavelet transform ultrasonic imaging can be effectively applied to detect and size internal defects without any reference information, which represents a valuable outcome for various applications in the industry. View Full-TextPeer ReviewedPostprint (published version

Air-Coupled Ultrasonic Transducers for the Detection of Defects in Plates

In order to minimise the problems due to the acoustic impedance mismatch between solids and air, the non destructive testing of materials using ultrasonic transducers generally requires either contact transducers or immersion transducers to be used [1]. Air-coupled transducers however would be very advantageous for testing structures which must be not contaminated with couplant and also for all in-situ industrial applications. Although the propagation of ultrasonic waves from laser generation [2] involves air-coupling, the difficulties due to the experimental set-up of this technique and the financial investment it implies are two major disadvantages

Venting in the comparative study of flexural ultrasonic transducers to improve resilience at elevated environmental pressure levels

The classical form of a flexural ultrasonic transducer is a piezoelectric ceramic disc bonded to a circular metallic membrane. This ceramic induces vibration modes of the membrane for the generation and detection of ultrasound. The transducer has been popular for proximity sensing and metrology, particularly for industrial applications at ambient pressures around 1 bar. The classical flexural ultrasonic transducer is not designed for operation at elevated pressures, such as those associated with natural gas transportation or petrochemical processes. It is reliant on a rear seal which forms an internal air cavity, making the transducer susceptible to deformation through pressure imbalance. The application potential of the classical transducer is therefore severely limited. In this study, a venting strategy which balances the pressure between the internal transducer structure and the external environment is studied through experimental methods including electrical impedance analysis and pitch-catch ultrasound measurement. The vented transducer is compared with a commercial equivalent in air towards 90 bar. Venting is shown to be viable for a new generation of low cost and robust industrial ultrasonic transducers, suitable for operation at high environmental pressure levels

A review of miniaturised Non-Destructive Testing technologies for in-situ inspections

Non-destructive testing (NDT) techniques have become attractive trends of product manufacturing, installation and post-maintenance in the aerospace, automotive and manufacturing industry, because of its benefits such as cost saving, easy to use and high efficiency etc. With the industrial products becoming large-scale, high integration and complication, developing the NDT miniaturisation technique for in-situ inspections is highly demanded and becoming an inevitable trend. However, in-situ inspection using NDT have been limited by a number of factors, such as the heavy weight, large size or complex structure etc. This paper aims to systematically identify and analyse the current state-of-the-art of NDT miniaturisation techniques in research and innovation, and discuss the challenge and prospect of miniaturisation of the commonly used NDT techniques

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

Nondestructive characterization of the elastic properties of orthotropic composites with ultrasound

Due to the increasing use of composite materials in critical applications demanding light weight to high strength ratio, reliable evaluation tools are necessary. The field of ultrasound is a well known non-destructive method, in which the classical C-scan has already proven its usefulness in visualizing defects, delaminations, ... Though, because of the limitations for quantitatively characterizing a material using a C-scan, the quest for more sophisticated methods is a big challenge in current research. A polar scan, which makes use of oblique incidence of ultrasound, can serve as a prominent successor of more classical methods. By gathering the reflected (or transmitted) amplitude of the ultrasonic beam, one is able to built a polar plot which covers a certain solid angle. Typically, dark rings are observed in a polar plot which can be linked to the generation of critical bulk waves (pulsed regime) or to the generation of surface waves (harmonic regime). Both types of waves are vigorous entangled with the elastic constants of the material. This implicates that a polar scan is a great candidate tool to investigate anisotropic materials non-destructively, where the mapped amplitudes are a local fingerprint of the investigated material

Experimental and numerical polar scans of several anisotropic materials using pulsed and harmonic ultrasonic beams

Ultrasonic non-destructive testing is a well known technique in present days, in which the C-scan is the most wide spread. Though, because of the inherent limitations of most methods to quantitatively characterize (damaged) composite materials, the quest for more sophisticated methods is put forward. This study reports experimentally registered polar scans using an in house developed ultrasonic test setup for some typical composite materials. Both pulsed and harmonic ultrasonic beams are considered, which impinge onto the immersed anisotropic layer under investigation. Numerical computations are shown and compared with the experimental results. The experimental polar scan of a carbon fabric/PPS laminate with an artificially added delamination shows a drastic change in the observed patterns, compared to the one of the undamaged carbon fabric/PPS laminate. Combined with the sensitivity to the local stiffness tensor, a polar scan can become a great tool to quantitatively evaluate (damaged) composite materials

The emerging application of ultrasound in lactose crystallisation

Ultrasonic processing is the industrial application of sound waves with a frequency above the upper limit of human hearing. Interest has arisen recently in the effects of ultrasound on the crystallisation of lactose as an innovative technology to improve its recovery and the control over its crystal properties. This not only will increase the financial profit for lactose manufacturers and improve the quality of lactose for specific applications, but will also improve the quality of end products manufactured with lactose as an ingredient