Search results for "Ultrasonic Wave"
showing 10 items of 20 documents
Generalised bisection method for optimum ultrasonic ray tracing and focusing in multi-layered structures
2021
Ultrasonic testing has been used for many decades, proving itself very efficient for detecting defects in many industrial sectors. The desire to apply ultrasonic testing to geometrically complex structures, and to anisotropic, inhomogeneous materials, together with the advent of more powerful electronics and software, is constantly pushing the applicability of ultrasonic waves to their limits. General ray tracing models, suitable for calculating the proper incident angle of single element probes and the proper time delay of phased array, are currently required. They can support the development of new imaging techniques, as Full Matrix Capture and Total Focusing Method, and the execution of …
Laser Ultrasonics Inspection for Defect Evaluation on Train Wheel
2019
Abstract Passengers’ safety and in-service life of wheelset axles play an important role in railway vehicles. For this reason, periodic inspections are necessary. Among non-destructive techniques, ultrasonic ones are widely applied in this field. The main disadvantage of conventional ultrasonic techniques is that the overall inspection of wheels requires the train to be put out-of-service and disassembly each part, which is time-consuming and expensive. In this paper, a non-conventional non-contact laser ultrasonic inspection for train wheels is proposed. The proposed method uses a laser interferometer to receive the ultrasonic wave without contact. The receiving system allows choosing the …
Effect of Low-Intensity Pulsed Ultrasound on Osteogenic Human Mesenchymal Stem Cells Commitment in a New Bone Scaffold
2017
Purpose Bone tissue engineering is helpful in finding alternatives to overcome surgery limitations. Bone growth and repair are under the control of biochemical and mechanical signals; therefore, in recent years several approaches to improve bone regeneration have been evaluated. Osteo-inductive biomaterials, stem cells, specific growth factors and biophysical stimuli are among those. The aim of the present study was to evaluate if low-intensity pulsed ultrasound stimulation (LIPUS) treatment would improve the colonization of an MgHA/Coll hybrid composite scaffold by human mesenchymal stem cells (hMSCs) and their osteogenic differentiation. LIPUS stimulation was applied to hMSCs cultured on …
Effects of Ultrasound-Assisted Extraction and Solvent on the Phenolic Profile, Bacterial Growth, and Anti-Inflammatory/Antioxidant Activities of Medi…
2020
© 2020 by the authors.
Ultrasonically-Assisted and Conventional Extraction from Erodium Glaucophyllum Roots Using Ethanol:Water Mixtures: Phenolic Characterization, Antioxi…
2020
The paper presents experimental results concerning the ultrasonically-assisted extraction of bioactive compounds from Erodium glaucophyllum roots. A comparison with conventional methodology is presented, and thereby the phytochemical composition and the antioxidant and anti-inflammatory activities of extracts are evaluated. The phenolic profile of Erodium extracts was analyzed by TOF&ndash
Application of integrative cloud point extraction and concentration for the analysis of polyphenols and alkaloids in mulberry leaves
2018
Abstract A simple and efficient method based on cloud point extraction and concentration combined with high performance liquid chromatography was developed for the simultaneous separation and determination of five target compounds (deoxynojirimycin, chlorogenic acid, rutin, isoquercitrin and astragalin) in mulberry leaves samples. Firstly, to obtain a high extraction rate, the ultrasound assisted extraction was developed on acid modified Triton X-114 system. Under the optimal conditions, the total maximum extraction yields of five target compounds reached 20.80 mg/g, which was superior to conventional solvent extraction. After the cloud point extraction and concentration, the HPLC analysis …
Effect of Supplementation with Wheat Bran Aqueous Extracts Obtained by Ultrasound-Assisted Technologies on the Sensory Properties and the Antioxidant…
2015
Phenolic compounds have antioxidant properties and activate endogenous detoxification defense systems able to scavenge the reactive species of oxygen. The external layers of wheat caryopsis, largely constituting by-products of the milling industry such as bran and various middlings, contain relevant amounts of phenolic compounds. The aim of the research has been to evaluate the effect of supplementation with wheat bran aqueous extracts, obtained by ultrasound-assisted technologies, on the sensory properties and antioxidant activity of dry pasta. The HPLC-DAD characterization of the extract evidenced the presence of ferulic and p-coumaric acids. The supplemented pasta showed significantly h…
An integrated structural health monitoring system based on electromechanical impedance and guided ultrasonic waves
2015
We propose a structural health monitoring (SHM) paradigm based on the simultaneous use of ultrasounds and electromechanical impedance (EMI) to monitor waveguides. Methods based on the propagation of guided ultrasonic waves (GUWs) are increasingly used in all those SHM applications that benefit from built-in transduction, moderately large inspection ranges, and high sensitivity to small flaws. Meantime, impedance-based SHM promises to adequately assess locally the structural integrity of simple waveguides and complex structures such as bolted connections. As both methods utilize piezoelectric transducers bonded or embedded to the structure of interest, this paper describes a unified SHM para…
Thermodynamics, transport phenomena, and electrochemistry of external field-assisted nonthermal food technologies
2017
Interest in the development and adoption of nonthermal technologies is burgeoning within the food and bioprocess industry, the associated research community, and among the consumers. This is evident from not only the success of some innovative nonthermal technologies at industrial scale, but also from the increasing number of publications dealing with these topics, a growing demand for foods processed by nonthermal technologies and use of natural ingredients. A notable feature of the nonthermal technologies such as cold plasma, electrohydrodynamic processing, pulsed electric fields, and ultrasound is the involvement of external fields, either electric or sound. Therefore, it merits to study…
Influence of laser beam profile on the generation of ultrasonic waves
2011
The different ultrasonic fields generated in metallic materials by a laser beam with flat and Gaussian profile are investigated experimentally and using the finite element method (FEM). A high power laser beam irradiating a solid surface produces elastic waves with a mechanics that depends on many parameters, including the profile of the laser beam. The influence of the beam profile is investigated with the FEM analysis, considering the temperature dependence of material properties.