Papers by Keyword: Ultrasound

Abstract: The use of ultrasonic smoothing methods for metal sheet materials opens up new opportunities for improving their performance properties. The paper considers the possibility of increasing the axial stiffness of aluminium thin-walled machine parts by reducing the size of their grains and creating conditions for obtaining nanostructured formations. It has been found that the yield strength of the 8011 grade foil treated with two-way ultrasonic smoothing, depending on the depth of the hardened layer, microstructure and grain size, initially decreases to the middle section, and then increases to its largest value. According to a similar relationship, the relative elongation, i.e. the plasticity of a thin-walled part, changes which also confirms the possibility of formation of nanostructures in the studied layers. Experimental studies have established that the two-way ultrasonic treatment of multilayered plates made of aluminium 8011 grade foil with a thickness of 0.42 mm allows to provide high plasticity and to increase its axial rigidity up to 20.6%, thereby improving the manufacturability of complex machine parts from thin-walled plates by the methods of cold treatment.

Abstract: Bundles or fabrics of sized glass fibres were treated by a dielectric barrier discharge plasma in a He/CF₄ gas mixture at atmospheric pressure with and without ultrasonic irradiation. The plasma treatment introduced fluorine both inside and outside of the fibre bundle, decreasing wetting of glycerol. Ultrasonic irradiation markedly increased the fluorine content as well as the silicon, calcium, and aluminium contents, indicating simultaneous fluorination and preferential etching of organic components. It is indicated that plasma treatment in a He/CF₄ gas mixture can be used for controlling the surface properties of glass fibre bundles, and that ultrasonic irradiation can enhance functionalization and etching.

Abstract: Designed experimental setup, and a prototype of the original devices for athermic relaxation of thermal residual stresses in openwork welded constructions of large dimensions for the rational use of energy high-frequency acoustic (ultrasonic) fields, conducted laboratory studies and pilot tests in real conditions of production. Ultrasonic relaxation when welding thin-walled constructions standard openwork rolled steel profiles 10 large dimensions (up to 3 x 10 m). It has been established that with a decrease in the time of ultrasonic relaxation, the efficiency of its use decreases somewhat. Therefore, in an industrial environment, it is advisable to use the duration of ultrasonic treatment in the range of 0.02-0.04 min per mm of weld length.

Abstract: The key and most energy-consuming process in obtaining inulin is the extraction process. The effectiveness of technology as a whole depends on this procedure. The present research is devoted to studying statics and kinetics of inulin water extraction from artichoke with the purpose of intensification, optimization and modeling of extraction process. Analysis of technical and patent literature has allowed to reveal the ways of aggregation of inulin extraction, in particular, by influence of ultrasonic oscillations on the object of processing. To study the statics of the extraction process, i.e. equilibrium states of the system of interacting substances with the purpose of determining equilibrium concentrations at different temperatures with the use of ultrasonic radiation, kinetic laws of the process and to select rational operating parameters and extraction process intensification, a series of experiments and experimental data processing were carried out. On the basis of the obtained data the process modeling is carried out and the model of mass transfer while inulin extraction is calculated. After have been analyzed the obtained results, in particular, fields of inulin concentration in Jerusalem artichoke and kinetic curves of extraction, it was concluded that in the process of extraction there are slight gradients of concentrations observed, which cause "soft" extraction modes. Furthermore, ultrasonic treatment application at the frequency of radiation 20-22 kHz reduces the duration of the extraction process and significantly increases specific output of inulin. The equations obtained are necessary not only to determine the duration of extraction and its rational mode parameters, but also to model the extraction process mathematical results. These research results can be used in the field of food science and industry, as well as in the development and design of food equipment.

Abstract: Research conducted aimed to compare the hybrid ultrasonic-thermal cutting technology with the classic thermal cutting one. The experimental program was carried out on the ISIM designed hybrid equipment, operating at a frequency of 35 KHz, with a cutting geometry of the ultrasonic horn - sonotrode and the thermal anvil designed specifically for the task at hand; the first phase of the experimental program was developed on the thermal cutting module, the second one was performed on the US-thermal hybrid module, both modules being part of the hybrid cutting equipment designed and patented by ISIM Timisoara. The research performed in this present paper, intends to highlight the benefits of the hybrid cutting technology when compared to classical thermal cutting, in order to process two types of materials with different specifications and dimensions. After visually inspection cut materials have been then compared with automotive seatbelt quality standard IATF - International Automotive Task Force 16949. Experiments highlighted that hybrid ultrasonic-thermal cutting process has a significant influence on the quality of processed materials when compared to classic thermal cutting process, which in some cases makes the materials unsuitable for use in the automotive industry. The paper further presents two types of technology data sets suitable for 2 types of materials and up to automotive industry requirements.

Abstract: The influence of ultrasonic impact treatment on the corrosion resistance of 17G1S steel has been studied. It has been ascertained that the treated surface passivation effectiveness is determined by the optimal combination of ultrasonic treatment mode and choice of a corrosion inhibitor in the corrosion sites treatment. It is shown that ultrasonic impact treatment has a double action: increasing of corrosion resistance and hardening of steel.

Abstract: The paper describes a cause of the geometric accuracy degradation of slender metallic products during their operation, which consists in the relaxation of residual stresses accumulated while product manufacturing. The most promising technology among the existing technologies of residual stress relaxation is based on the use of vibromechanical vibrations. This technology has high performance and low energy consumption. The reason for the relaxation of residual stresses under the action of vibromechanical vibrations is the gradual accumulation of internal energy, which leads to plastic dislocation shifts upon reaching a critical level. The dislocation motion under the action of vibromechanical vibrations continues until the dislocations take a more compact layout that corresponds to the equilibrium energy state. For technological implementation of the process there was developed a method of ultrasonic stabilization of elastic plates, which serve as sensing elements in differential-pressure transducers. The experimental studies of ultrasonic stabilization are carried out. According to the results of the studies, there have been conducted tests of the microstructure of the control samples. It is established that the samples of steel 20CH13 subject to ultrasonic treatment have a more uniform structure than the samples after the factory technology of long "aging". This confirms the assumption about the structural-energy processes occurring during vibromechanical relaxation of residual stresses. The technology of ultrasonic stabilization can be recommended as a replacement to the "aging" technology on the basis of the obtained results.

Abstract: Recently, environmental damage caused by pest, invasive species Nutria has become an issue in Tottori Prefecture and development of an effective control method is in demand. Therefore, we have developed a robot that could identify pest by using ultrasonic sensor. The benefits of using this robot is that it is difficult to be influenced by environmental conditions and easily recognizes three dimensional input. Unfortunately, this robot could only confirm the presence of target object but could not identify the object, which means it could not differentiate whether the object is human or pest. In this paper, we have invented a robot that could visualize the object by using frequency-modulated ultrasound and Self-Organizing Map (SOM).

Abstract: The conditions for the formation of epoxy composite coatings filled with nanodispersed particles of fullerene black are investigated. The efficiency of the use of electromagnetic and ultrasonic radiation for modifying the composition based on the epoxy matrix has been confirmed. The paper describes the optimum composition and mode of formation of epoxy composite materials filled with fullerene black.

Abstract: This paper presents the research method of hardening process of gypsum binders and composites, based on them, using the ultrasonic method. Modern construction composites, based on higher water resistance gupsym, contain the coarse aggregate particles, giving them heat and sound insulating properties. One of the frequent purposes, designing such composites, is the slowdown of the processes of setting, so it allows the builders to work with the material for a sufficiently long period. The use of standard control penetration methods of the setting processes for the considered composites becomes difficult because of the presence of course particles in the binder paste. The ultrasonic method is proposed to use alternatively to study the process of setting. For its implementation, the technique has been developed, based on the use of ultrasound systems for quality control of concrete products. The transit time of ultrasonic signals through the layer of hardening binder paste with the fixed thickness was measured in a regular intervals until completely setting. On the basis of the obtained data, the ultrasound velocity was calculated and the setting time was determined. For this purpose, a differential curve of the time of ultrasound transmission was plotted, and the period was considered, at which the transition to the steady-state condition was carried out, it is equivalent to the end of the setting. The initial setting was determined by the first trip of the measuring equipment, corresponding moment of the formation of the primary crystal structure of the composite, which has sound-transmission properties. To verify the values of the setting time, the simultaneous measurement of the plastic strength of the model system was used. The moments of the beginning and the end of the setting, as well as the ultrasound velocities which were typical for these moments, were determined with the plastic strength. The obtained velocity values allowed to find the setting times of other composites. The actual setting time is estimated based on the values, obtained by all the available methods. The model, based on percolation theory, has been proposed for analyzing the physicochemical phenomena during the setting.