No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
Ultrasonic cleaning and washing of surfaces
Abstract
This chapter first addresses the emergence of ultrasonic cleaning technology. The principles and mechanism of application are discussed, and an explanation of the benefits of ultrasonic cleaning is provided. Ultrasonic cleaning also has limitations, which are revealed, along with reasons for these shortfalls. This chapter serves as a practical guide for maximizing and monitoring the effectiveness of an ultrasonic cleaning system. Advances in ultrasonic technology are explored along with their impetus. Finally, this chapter speculates on the future of ultrasonic cleaning. An appendix on recent developments in ultrasonic washing of textiles also is included.
... We hypothesized that an ultrasonic technology system could offer reliable and reproducible cleaning, as ultrasound waves are able to remove contaminants and clean hard-to-reach areas (Fuchs 2015). Further, the use of this technology to clean environmental samples has been already reported (Godzik et al. 1979;Foo and Tan 1998;Miekeley et al. 1998;Mill an et al. 2006, Sierra et al. 2012. ...
... We tested whether washing would improve if we forced the full immersion of samples in the washing solution. Finally, some authors indicate that washing by ultrasound is more efficient if the temperature of the washing agent is increased (Fuchs 2015). However, as in some studies cold agents are used (Vese y et al. 2012) we analyzed this factor here. ...
... The effects observed of water temperature contrast strongly with those reported by Fuchs (2015) and Mason (2016), who indicated that a temperature of the washing agent close to 50-60 C improved washing efficacy. In our working conditions, such a high-temperature range could damage the plant tissues and increase Hg volatility. ...
Effective cleaning of biological samples is a critical step in environmental studies. However, the literature lacks standardized cleaning procedures and protocols and there is little information about how even the most basic conditions may affect cleaning efficiency. Here, leaves of different species were first exposed to the soil naturally containing mercury particles and then washed in an ultrasound water bath under the following conditions: newly cleaned/reused beakers, water temperature, sample immersion/free-floating, sample quantity, and the number of washing cycles. Additionally, the effects of sample pubescence on cleaning efficacy were also assessed. Results indicated that the best cleaning efficacy was recorded when samples were placed in cold water under forced immersion and beakers were cleaned between washing cycles. At least two of these three conditions were needed for adequate washing. The results also indicated that, for the glabrous leaves, a cumulative leaf surface area of ≤10,000 mm² was efficiently cleaned after 3–5 washing cycles, while as pubescence increased, 9–11 cycles were needed and often the sample quantity had to be reduced (<5,000 mm²). Our experiments reveal that cleaning can be optimized by applying easy procedures and according to individual sample typology, resulting in faster and more effective cleaning.
Novelty statement
The cleaning of samples is a frequent stage in the analytical processes of phytoremediation studies. This work provides new and valuable information to optimize the cleaning of plant samples by simply applying ultrasonic technology and distilled water. In fact, we have tested the influence of some factors never taken into account previously.
... Vapor bubbles pulsating near solid boundaries can collapse in a few periods of acoustic waves, resulting in rapid, vigorous dynamic motions with high-speed liquid jets and shock waves [22,25,26]. In contrast, gas bubbles exhibit relatively moderate dynamic motions owing to the gas cushion and thus have a relatively long life time [15,18,[27][28][29]. ...
... For instance, a few research groups have suggested techniques to improve the cleaning effect by controlling the dissolved gas content, but the results have been inconsistent. Some groups propose that liquids with a lower gas content can be used to improve cleaning performance [28,[30][31][32], while other groups report that large amounts of dissolved gas can be advantageous for improving cleaning efficiency [29,33]. To advance ultrasonic cleaning technique by selectively exploiting gas or vapor bubbles, it will be necessary to directly compare the cleaning effects of gas and vapor bubbles. ...
... Hence, ultrasonic cleaning with degassed water needs a relatively higher acoustic pressure. Ultrasonic waves with an excessively high acoustic pressure may have negative effects, such as surface damage and temperature rise of the cleaning medium [3,4,28,44], so we deduced that surfaces with weakly adhering contaminants can be advantageously cleaned with non-degassed water. Fig. 4b shows the results for contamination condition II (strong adhesion on hydrophilic surface). ...
The dynamic actions of cavitation bubbles in ultrasonic fields can clean surfaces. Gas and vapor cavitation bubbles exhibit different dynamic behaviors in ultrasonic fields, yet little attention has been given to the distinctive cleaning effects of gas and vapor bubbles. We present an experimental investigation of surface cleaning by gas and vapor bubbles in an ultrasonic field. Using high-speed videography, we found that the primary motions of gas and vapor bubbles responsible for surface cleaning differ. Our cleaning tests under different contamination conditions in terms of contaminant adhesion strength and surface wettability reveal that vapor and gas bubbles are more effective at removing contaminants with strong and weak adhesion, respectively, and furthermore that hydrophobic substrates are better cleaned by vapor bubbles. Our study not only provides a better physical understanding of the ultrasonic cleaning process, but also proposes novel techniques to improve ultrasonic cleaning by selectively employing gas and vapor bubbles depending on the characteristics of the surface to be cleaned.
... Surface cleaning is probably the most famous application of ultrasound since its first industrial uses in the 50 s (Bulat, 1974;Fuchs, 2015;Mason, 2016;Yao et al., 2020). Ultrasound-assisted removal of surface contaminants is now widely used in many fields, including electronics for printed circuits, optics for precision instruments, jewelry washing, industrial machinery and metal washing, etc. ...
... Ultrasound-assisted removal of surface contaminants is now widely used in many fields, including electronics for printed circuits, optics for precision instruments, jewelry washing, industrial machinery and metal washing, etc. Compared to other techniques (spray, immersion, agitation, etc.), ultrasonic cleaning is advantageous because it is adapted to complex surface shapes, offers access to small cavities and hidden areas, avoids the use of concentrated and hazardous solvents and proposes milder conditions for the treated materials and the operator (Fuchs, 2000(Fuchs, , 2015Mason, 2016;Yao et al., 2020). Despite the democratization of ultrasonic cleaning applications and devices, the characterization, understanding and capabilities of the generated processes at the solid/liquid interface are still unclear. ...
... Most ultrasonic cleaning approaches are performed in the 20-200 kHz frequency range which is directly related to the phenomenon of acoustic cavitation (i.e., the nucleation, growth and rapid implosive collapse of gas and vapor filled microbubbles) (Fuchs, 2015;Mason, 2016;Mason et al., 2011). The size of the particles that can be removed from a surface generally decreases with increasing ultrasonic frequency, moving from industrial cleaning applications (machined parts, equipment.) ...
UNGG cladding nuclear wastes constitute a huge volume of Mg-based materials that raises economic and safety concerns, particularly due to their radioactivity coupled to the potential generation of H2 gas under deep underground disposal. Their significant decontamination would result in more secure and less expensive storage, with a better containment of the separated long-lived radioisotopes that could enter in a classical channel. Sonication of genuine UNGG cladding materials and simulants at 345 kHz in 0.01 M oxalic acid solution (20 °C) allowed the structuring of their surfaces with the observation of homogeneously distributed craters of 20-40 µm in diameter. After a thorough characterization and comparison of the ultrasound effects generated at the surface, the various samples were artificially contaminated and characterized before sonication. The complete and rapid sonochemical decontamination of Mg-based materials was then observed, in addition to the removal of the carbon layer promoting corrosion on the inner UNGG cladding. The extension of sonication allows the neo-formed brucite (Mg(OH)2) and zirconium-based phases to accumulate on the surface, thus contributing in a slight but continuous surface recontamination process. This phenomenon results from the re-adsorption of uranyl cations from the solution which can be avoided by optimizing the duration of treatment.
... [125,126] Cleaning or removal of dirt and contaminants from the target surfaces can be accomplished by either chemical dissolution by solvents or physical erosion by external forces. [127] In case of ultrasonic cleaning, two primary factors drive the cleaning process in both physical and chemical approaches: i) the nonsymmetric collapse in the vicinity of a solid surface, which can directly damage the adhered dirt and contaminants; ii) the acoustic streaming in ultrasonic field, which can reduce the thickness of hydrodynamic boundary on the surface and enhance the mass transfer at the interface of contaminant and solvent. [51] The biggest advantage of ultrasonic cleaning is that it has much less limit of the shape and size of objects and it can easily get access to small cavities and blind spaces in treated materials that are not accessible for other conventional cleaning approaches. ...
... Ultrasonic cleaning application as a function of frequency. [127] In general, most ultrasonic cleaning systems are based on frequency from approximately 20 to 200 kHz. [127] Approximately, 20 to 40 kHz is suitable for industrial machine metals cleaning, while frequencies of 60 to 80 kHz are often used for more precise cleaning applications. ...
... [127] In general, most ultrasonic cleaning systems are based on frequency from approximately 20 to 200 kHz. [127] Approximately, 20 to 40 kHz is suitable for industrial machine metals cleaning, while frequencies of 60 to 80 kHz are often used for more precise cleaning applications. Intermediate to high frequency (100 to 200 kHz) ultrasonic systems are introduced for very delicate parts cleaning, such as medical and optical instruments. ...
The dismantling of UNGG reactors produces large volumes of contaminated metallic materials. Among these, magnesium-based alloys which are known as highly reactive metals, have a high risk of corrosion and can generate hydrogen gas that can cause serious damages during storage. In order to reduce the volume of generated radioactive effluents and downgrade nuclear wastes, sonochemistry can be applied as an efficient technology for metallic surface decontamination. Sonochemistry deals with the effects of ultrasound waves on chemical reactions in solution. The effects observed in sonochemistry originate from the acoustic cavitation phenomenon, which is the nucleation, growth and rapid implosive collapse of gas and vapor filled microbubbles. Excited species and radicals can be generated in the formed plasma and light (sonoluminescence) is emitted. When the bubble collapse takes place in the vicinity of a solid surface, it produces violent shock waves and microjets directed towards the surface. These physical effects strongly contribute in ultrasonic cleaning, surface depassivation and decontamination.This study focuses on: 1) the cavitation behaviors near a solid surface; 2) the ultrasonic structuration of extended magnesium surfaces; 3) the ultrasonic decontamination of radioactive metal surfaces. The sonochemical activity is evaluated by measuring H2O2 yields, sonochemiluminescence distribution and sonoluminescence spectra. Surface structuration and decontamination effects are followed by means of SEM, EDS, FTIR, Raman, XRD, wetting behavior analysis, mass spectrometry and ICP-AES.The investigations reveal a strong ultrasonic frequency dependency of the cavitation activity and distribution and of the effects generated on the Mg samples. A homogeneous spatial repartition of sonochemical activity is observed at frequencies ≥ 100 kHz. Asymmetrical bubble collapse is found more likely to happen near the solid surface at high frequency ultrasound. A golf-ball like extended structure is observed at frequencies between 100 and 362 kHz. It is shown that such architectures result from the ultrasonically controlled dissolution of the Mg surface. Heterogeneous nucleation provided by the creation of defects by ultrasound and the release of H2 gas are supposed to be at the origin of the crater formation. Decontamination of radioactive surfaces of Mg and Mg alloys demonstrate rapid ultrasonic cleaning followed by a slow recontamination process which is due to the adsorption of brucite formed on the surfaces of Mg or its alloys.
... In ordinary kitchen foil, this pitting becomes perforations [24]. The efficiency of ultrasonic cleaners depends on the size and number of cavitation bubbles, temperature, viscosity, surface tension, and diffusion rate of the liquid [1]. For this research, an aluminuim foil corrosion test was performed in room conditions. ...
... The main objectives of this paper are to combine the design, tuning and validation of ultrasonic cleaners as follows: (1) to design (placement and the number of ultrasonic transducers) an ultrasonic cleaner based on the acoustic pressure distribution of the system in a simulation environment, (2) to provide a gateway for how to design a driving circuit for ultrasonic transducers based on the results of the impedance analysis of the transducer, (3) to tune the system using replicated hydrophone technique so that we can have quantifiable results whether the ultrasonic cleaner is working in the resonance region or not, (4) to provide a generic validation method for finding the efficiency of ultrasonic cleaners easily, effectively, and cheaply. This paper is organized as follows; in Section 2, a detailed methodology is discussed. ...
Over the past decade, ultrasonic cleaners have been widely used in many industries. Now, this technology is finding its way into homes for vegetable, fruit, and clothes cleaning. In widely used ultrasonic cleaners, piezoelectric transducers are externally attached to the steel tank to generate ultrasonic waves inside the tank. Based on the impedance data of the piezoelectric transducers, the driving circuit was tuned to generate the required frequencies inside the cleaning tank. This paper discusses the design, development, and validation of an 800 mL tank capacity ultrasonic cleaner driven with a piezoelectric disc actuator. To achieve an optimum cleaning action without surface abrasion, several characteristics need to be considered in this complex relationship. The placement of transducers has been investigated according to the pressure distribution inside the liquid medium. The optimized ultrasonic cleaner design, along with a class-D half-bridge circuit, was developed to drive the ultrasonic transducer in the resonance frequency range. To validate the optimal design and driving frequency, the acoustic spectrum generated inside the tank was measured using a piezoelectric sensor and FFT analysis was performed. To validate the cleaning effect, a qualitative test based on aluminuim foil perforations was performed. The perforation area in the foils was quantitatively measured using image processing based on the YOLO V5 technique. The proposed image processing technique has an accuracy of 97 % in the detection of perforation areas in the aluminuim foil test.
... An ultrasonic bath is widely used for cleaning glass, medical equipment, etc. [1,2]. Furthermore, an ultrasonic bath is widely used in laboratories for the dispersion of nanoparticles in various liquids [3][4][5][6]. ...
... At the final moment of the violent bubble collapse, the temperature and pressure inside the bubble increase to several thousand Kelvin and several hundred of atmospheric pressure or more because the work performed on a collapsing bubble by the surrounding liquid heats up the bubble [2,12,[19][20][21][22]. In other words, it is a quasi-adiabatic collapse, where "quasi-" means that appreciable thermal conduction takes place between the heated interior of a (1) The chemical products from cavitation bubbles under ultrasound are mostly oxidants because H atoms, which are reducing agents, formed inside a bubble by the dissociation of water vapor hardly penetrate into the liquid phase due to the chemical reactions with O 2 and OH inside a bubble as follows [53]. ...
It has been experimentally reported that not only oxidation reactions but also reduction reactions occur in aqueous solutions under ultrasound without any additives. According to the numerical simulations of chemical reactions inside an air or argon bubble in water without any additives under ultrasound, reducing agents produced from the bubbles are H, H2, HO2 (which becomes superoxide anion (O2−) in liquid water), NO, and HNO2 (which becomes NO2− in liquid water). In addition, H2O2 sometimes works as a reducing agent. As the reduction potentials of H and H2 (in strongly alkaline solutions for H2) are higher than those of RCHOH radicals, which are usually used to reduce metal ions, H and H2 generated from cavitation bubbles are expected to reduce metal ions to produce metal nanoparticles (in strongly alkaline solutions for H2 to work). It is possible that the superoxide anion (O2−) also plays some role in the sonochemical reduction of some solutes. In strongly alkaline solutions, hydrated electrons (e−aq) formed from H atoms in liquid water may play an important role in the sonochemical reduction of solutes because the reduction potential is extremely high. The influence of ultrasonic frequency on the amount of H atoms produced from a cavitation bubble is also discussed.
... The suitable frequency range for cleaning goes from 20 to 40 kHz dominated by transient cavitation bubbles and non-directional acoustic streaming at 400 km/h (Jordens et al., 2019). Mechanical energy supplied by the cavitation bubble enhances the cleaning process by conveying the cleaning solvent to various contaminants (Fuchs, 2015). Ultrasonic parameters (power intensity, frequency, system types (bath or probe) and modes (continuous or pulse) affect cleaning efficacy, apart from other extrinsic elements (duration, temperature, solvent medium, and sample-to-solvent ratio). ...
... The bubble at this frequency range is destructive because of the high-pressure collapsing bubble, which is larger in size and forms a secondary phenomenon, namely the microjet. It is believed that this process contributed to the erosion of the shells' surface, hence increasing the rate of decontamination assisted by the acoustic streaming, which carried away the contaminant's particles and prevented them from reattaching to the shell (Fuchs, 2015). However, a similar unforeseen impact of ultrasound treatment at 0.35 W/cm 2 in pulse mode (0.35-P) for 15 min was found to be less pronounced compared to 25nullmin, consistent with the previous result section (WI). ...
... A schematic of the vacuum boiling experimental facility is shown in Figure 2. First, a glass vial of a known wettability was filled with 3 mL of 18.2 MΩ·cm degassed deionized water and placed inside the vacuum desiccator. The deionized water was degassed using the thermal degasification method, i.e., by boiling the deionized water to remove any dissolved gas(es) followed by cooling it down to room temperature in a closed container [31][32][33]. Then the desiccator was closed, and the vacuum was set at 979 mbar abs. pressure (1 inHg rel.) for 15 min. ...
... A schematic of the vacuum boiling experimental facility is shown in Figure 2. First, a glass vial of a known wettability was filled with 3 mL of 18.2 MΩ•cm degassed deionized water and placed inside the vacuum desiccator. The deionized water was degassed using the thermal degasification method i.e., by boiling the deionized water to remove any dissolved gas(es) followed by cooling it down to room temperature in a closed container [31][32][33]. Then the desiccator was closed and the vacuum was set at 979 mbar abs. pressure (1 inHg rel.) for 15 min. ...
Nucleation is the formation of a new phase that has the ability to irreversibly and spontaneously grow into a large-sized nucleus within the body of a metastable parent phase. In this experimental work, the effect of wettability on the incipiation of vacuum-driven bubble nucleation, boiling, and the consequent rate of evaporative cooling are studied. One hydrophilic (untreated), and three hydrophobic (chlorinated polydimethylsiloxane, chlorinated fluoroalkylmethylsiloxane and (heptadecafluoro-1,1,2,2-tetrahydrodecyl)triethoxysilane) glass vials of different wettabilities were filled with degassed deionized water and exposed to a controlled vacuum inside a transparent desiccator. The vacuum was increased by 34 mbar abs. (1 inHg rel.) steps with 15-min waiting period to observe bubble nucleation. The average onset pressures for gas/vapor bubble nucleation in CM, CF, and HT vials were 911 ± 30, 911 ± 34, and 925 ± 17 mbar abs., respectively. Bubble nucleation was not observed in hydrophilic vial even at 65 mbar abs. pressure. During the vacuum boiling at 65 mbar abs., the average temperatures of water in hydrophilic, CM, CF, and HT vials reduced from room temperature (~22.5 °C) to 15.2 ± 0.9, 13.1 ± 0.9, 12.9 ± 0.5, and 11.2 ± 0.3 °C, respectively. The results of this study show that the wettability of the container surface has a strong influence on the onset vacuum for vapor/gas bubble nucleation, rate of vacuum boiling, and evaporative cooling. These findings are expected to be useful to develop wettability-based vacuum boiling technologies.
... Especially, the acoustic streaming effect of the ultrasonic field has been proved to enhance convection heat transfer by forming the vortical flows in the heat transfer medium [30]. The cavitation effect of the ultrasonic field induces the bubbles generation in the liquid, and the cavitation bubbles go through the iterative compressed and expanded until they are detonated, so as to enhance convection heat transfer [31]. Nevertheless, it is undeniable that, as an active heat transfer enhancement method, applying the external field consumes a portion of electrical energy for simultaneous operation, which increases the operation cost of the TES system and reduces the TES efficiency [29]. ...
... As shown in Fig. 8(e), plenty of tiny bubbles are generated in the liquid nano-PCMs as a consequence of the ultrasonic cavitation. During the rarefaction and compression cycles of the bubbles, these bubbles will be expanded, compressed and grown-up until detonated by the alternating positive and negative pressure of the ultrasonic field [31]. When the bubbles break, they will generate a huge instant temperature and pressure gradient, thereby forming the effects of microjet, shock waves and instantaneous high temperature [28]. ...
To further improve the performance of thermal energy storage (TES) system with phase change materials (PCMs), this paper proposed a novel method, i.e. combining the additions of TiO2 nanoparticles, metal foam and the provision of ultrasonic field, investigated its synergetic effects in enhancing conduction and convection heat transfer. The thermal characteristics, including the TES time distributions and the energy consumption of the TES system, were discussed to evaluate the combined effects of TiO2 nanoparticles and ultrasonic field on the TES rate and TES efficiency. The results showed that the latent TES time reduction index reached 46.50%, when the TiO2 nanoparticles concentration was 5.0 wt% and the ultrasonic power was 100 W, while the TES efficiency dropped to 10.66%. Increasing TiO2 nanoparticles concentration and ultrasonic power positively improved the TES rate due to conduction heat transfer enhanced by nanoparticles and convection heat transfer enhanced by the acoustic streaming effect and the cavitation effect of the ultrasonic field, but which negatively reduced the TES efficiency mainly due to the energy consumption of the ultrasonic field. Therefore, the effects of the ultrasonic field introduced at four action stages on the TES rate and TES efficiency were compared, and it confirmed that introducing ultrasonic field at the latent TES stage was better than that in the sensible TES stage. Additionally, the proposed novel combined method needed to consider the priority relationship between TES rate and TES efficiency for designing the TES system, favoring the potentials for further advances in TES applications.
... While keeping the compatibility with Si wafer standard processing steps, ultrasonic treatment of surfaces can be effective in passing several obstacles to achieving wafer cleaning mentioned above. Ultrasonic cleaning employs an ultrasonically activated liquid with a submerged wafer used to achieve or enhance the removal of surface contaminants [60]. Ultrasonic irradiation involves a variety of complex mechanisms, including mechanical vibration and appropriate pressure gradients, microcavitation bubbles that oscillate and dance around due to Bjerknes force [39,61], acoustic streaming flows, etc. ...
... Therefore, because the bubble size drops with increasing the ultrasonic frequency and the bubble implosions become less violent, the energy released by each imploding cavitation bubble decreases with the ultrasonic frequency. However, the number of the imploding events increases due to increased number of sound waves passing through the liquid at a higher frequency [60]. ...
The usage of power ultrasound for sonochemical processing of Si wafers and thin layers of amorphous Si and SiGe alloys is described. Over the last decade different industries have become increasingly drawn to sonochemistry because it provides a green and clean alternative to conventional technologies, particular in the areas of processing of silicon-based materials for photovoltaic applications. Two techniques related to ultrasonic cleaning of Si wafers and sonochemical modification of Si, SiGe and a-Si/SiGe surfaces in hydrocarbon solutions of chloroform (CHCl3) and dichloromethane (CH2Cl2) are discussed. The occurrence of cavitation and bubble implosion is an indispensable prerequisite for ultrasonic cleaning and surface processing as it is known today. The use of higher ultrasonic frequencies to expand the range of ultrasonic cleaning and processing capabilities is emphasized. Although exact mechanisms of an improved photoelectric behavior of Si-based structures subjected to power ultrasound are not yet clarified in many cases, the likely scenarios behind the observed photovoltaic performances of Si, SiGe and a-Si/SiGe surfaces are proposed to involve the surface chemistry of oxygen and hydrogen molecules as well hydrocarbon chains.
... 28 High concentrations of aluminium ions have well documented toxic effects so the substitution of alumina (aluminium oxide) beads is not recommended. 14,29,30 Moreover, there have been reports of metal hypersensitivity in patients whose implant failed as a result of implant exposure (scalp erosion). 31 That metal ions and silicon are involved in bone formation (and resorption) is well known. ...
... It is an effective technique for cleaning a variety of surfaces, from the delicate removal of particles on semiconductor wafers to the removal of scale and oxides from steel strips. 30 The decision to subject the samples to additional ultrasonic cleaning steps was made in the expectation that its physical effects would reduce the number of inclusions present on the implant surface. This was indeed the case as evident from Figure 5, which shows the effectiveness of this form of treatment when applied to the coupons prior to bead blasting (Set 1.2). ...
Cranioplasty implants are routinely fabricated from commercially pure titanium plates by maxillofacial prosthetists. The differing fabrication protocols adopted by prosthetists working at different hospital sites gives rise to considerable variations in surface topography and composition of cranioplasty implants, with residues from the fabrication processes having been found to become incorporated into the surface of the implant. There is a growing recognition among maxillofacial prosthetists of the need to standardise these protocols to ensure quality and consistency of practice within the profession. In an effort to identify and eliminate the source of the inclusions associated with one such fabrication protocol, the present study examined the surfaces of samples subjected to each of the manufacturing steps involved. Surface and elemental analysis techniques identified the main constituent of the surface inclusions to be silicon from the glass beads used to texture the surface of the implant during fabrication. Subsequent analysis of samples prepared according to a revised protocol resulted in a more homogeneous titanium dioxide surface as evidenced by the reduction in area occupied by surface inclusions (from 8.51% ± 2.60% to 0.93% ± 0.62%). These findings may inform the development of improved protocols for the fabrication of titanium cranioplasty plates.
... Solvent cleaning can be combined with other cleaning techniques such as vapor degreasing, spraying, immersion, stir and ultrasonic scrubbing [8,9]. Ultrasonic cleaning or sonicate uses highintensity and high-frequency of sound waves is a common technique providing high-quality cleaning and removing foreign contaminated surfaces submerged in a liquid [10]. ...
... Both of stir and sonication process provided the same result as shown in Fig. 1 compared with washed plastic wastes by water (Fig. 1a). The sonication method was selected for further cleaning study because of lower energy consumption in term of temperature; moreover, ultrasonic-cleaning had an effective ability to penetrate and clean any surface that other techniques are not accessible [10]. There are five solvents for cleaning the plastic wastes: acetone, toluene, xylene, chloroform and tetrachloroethylene. ...
The plastics from municipal solid waste (MSW) were modified to improve cleanness for adding value. The stir and sonication were performed as cleaning processes. Xylene, tetrachloroethylene, chloroform, acetone and toluene were used as solvent cleaning. The most suitable cleaning process was sonication method with cleaning time of 5 min and the appropriate solvent was xylene for washing the plastic wastes for further study in terms of thermo-mechanical and rheological properties. The cleaning process was successful as evidence in thermogravimetric analysis (TGA) results. The properties of new plastics, cleaned plastic wastes and plastic wastes were compared and analyzed. Tensile strength of the specimens from plastic wastes was slightly decreased; however, elongation and impact strength of cleaned plastic wastes and plastic wastes sharply dropped as compared to new plastics. Tensile modulus of cleaned plastic wastes was slightly better than that of new plastics. Thermal stability of plastic waste was slightly lower than that of new plastic. Shear storage modulus (Gʹ), shear loss modulus (Gʺ) and shear viscosity (η) of new plastics showed the maximum value; on the other hand, those properties of cleaned plastic wastes and plastic wastes were similar. The cleaning method with solvent did not destroy thermo-mechanical and rheological properties of the cleaned plastic wastes.
... Through a combination of advancements in electronics, material science, and signal processing, modern ultrasound devices have developed from their roots in SONAR into a versatile technology that is fundamental to many scientific and industrial processes, as well as being integral to many everyday devices [1][2][3][4][5]. Today, ultrasound is used for imaging, flaw detection, surface cleaning, navigation, ranging, and haptics, among other applications across numerous fields [6][7][8][9][10][11]. However, it is perhaps most synonymous with its medical applications, particularly in medical imaging. ...
Drug delivery to the anterior and posterior segments of the eye is impeded by anatomical and physiological barriers. Increasingly, the bioeffects produced by ultrasound are being proven effective for mitigating the impact of these barriers on ocular drug delivery, though there does not appear to be a consensus on the most appropriate system configuration and operating parameters for this application. In this review, the fundamental aspects of ultrasound physics most pertinent to drug delivery are presented; the primary phenomena responsible for increased drug delivery efficacy under ultrasound sonication are discussed; an overview of common ocular drug administration routes and the associated ocular barriers is also given before reviewing the current state of the art of ultrasound-mediated ocular drug delivery and its potential future directions.
... Applications of ultrasonic techniques can be found in many aspects that include medical imaging (Carovac et al., 2011), material cleaning (Fuchs, 2015), process industries (Hauptmann et al., 2002), underwater imaging (Oralkan et al., 2002) and characterization of sediment and rock properties (Santamarina et al., 2001). ...
Elastic wave propagation in saturated porous rocks reflects the fluid and mineral
stiffness and their frequency-dependent interaction. Seismic imaging and borehole
measurements in the field use low-frequency, long-wavelength signals (Hz-to-kHz),
while standard laboratory-measurements operate in the MHz range. This thesis
advances broadband elastic wave propagation methods (quasi-static, cyclic loading,
first-mode resonance, and ultrasonic) to characterize intact rocks in order to gather
laboratory data relevant to field conditions.
Results show the critical effect of surface roughness at the specimen-endcap
interfaces on stiffness measured under quasi-static conditions; local strain
measurements using specimen-bonded strain gauges avoid seating effects.
Multi-mode low-frequency resonant column testing provides the most reliable
assessment of attenuation; attenuation increases and resonant frequency decreases
with vibration amplitude for all vibration modes (longitudinal, torsional, and
flexural). Ultrasonic P and S-wave velocities increase as a function of confining
pressure and during early stages of deviatoric loading; trends follow a Hertzian
power law. The corresponding α-factors and β-exponents exhibit a strong
correlation with specimen type. The combination of ultrasonic measurement and
coda wave analysis allows us to detect minute velocity changes during fluid invasion
and damage evolution. Differences in P-wave velocity in specimens saturated with
brine and supercritical CO2 are higher at seismic frequencies than in ultrasonic
frequencies.
The new experimental methods implemented in this research and the
comprehensive characterization studies provide new tools into intact rock
characterization and contribute new insights on the physical properties of intact
rocks and fluid-matrix interaction. Results highlight critical differences between
field values and standard laboratory measurements.
... Ultrasonic cleaning technology can use high-intensity, high-frequency sound waves to generate cavitation bubbles in liquids. The energy released by the implosion of cavitation bubbles provides micro-stirring at the liquid-contaminant interface [36]. ...
An increasing trend of research on microplastics (MPs) pollution in soil requires plenty of accurate data on MPs occurrence in soil samples. Efficient and economical methods of obtaining MP data are in development, especially for film MPs. We focused on MPs originating from agricultural mulching films (AMF) and presented an approach that can separate MPs in batches and identify them quickly. It mainly includes separation by ultrasonic cleaning and centrifugation, digestion of organic matter, and an AMF-MPs identification model. Adding olive oil or n-hexane to saturated sodium chloride constituted the best combination of separation solutions. Controlled experiments proved that the optimized methods improved the efficiency of this approach. The AMF-MPs identification model provides specific characteristics of MPs and can identify MPs efficiently. Evaluation results showed that the mean MP recovery rate reached 95%. The practical application demonstrated that this approach could conduct MPs analysis in soil samples in batches with less time and low cost.
... The utilization of ultrasonication was a key component in the STC process. Ultrasonication can speed up the dissolution of surface molecular contamination, along with particle displacement and removal, due to cavitation forces breaking up attractive or cohesive forces between a contaminant and a surface (Fuchs, 2015). This greatly aided the removal of introduced contaminants while also reducing the inherent propensity for shedding of the alumina coating on the STs. ...
The Sample Tubes on the Mars 2020 Perseverance rover were required to meet strict cleanliness standards for possible organic and inorganic contamination introduction to collected samples. There were also strict planetary protection cleanliness standards required to limit possible biological contamination. Together, these sets of standards also applied to associated hardware, like the Sample Tube hermetic seals. This created unique challenges to manufacturing, cleaning, and verifying the final cleanliness state of the Sample Tubes, which are the main focus of this publication. Documenting the final cleanliness state of the Sample Tubes is critical for future analysis of collected martian samples, of significant interest to the scientific community, and will have implications for possible future missions like Mars Sample Return. An accounting of events that led to the final delivered state of the Sample Tubes on Earth with regard to contamination control cleanliness requirements, precision cleaning, processing, and verification are provided.
... Inertial cavities collapse and generate shock waves when they enter higher-pressure regions or are exposed to pressure waves [16]. The shock waves are very strong, close to the imploding bubble but attenuate rapidly compared with a typical acoustic wave in the fluid. ...
This paper explains producing a novel ultrasonic system to remove/prevent biofouling growth from wind turbines' access ladders by means of producing local ultrasound cavitation. Using bespoke hardware, an array of high-power ultrasound transducers (HPUTS) and optimally synthesized signal types to remove/prevent biofouling growth from the ladder without violating the standard noise level in the sea is explained. This is a non-toxic and non-invasive solution to detach biofouling and prevent biofilm initiation on offshore structures. It is shown that the marinisation of the HPUT slightly shifts the main resonance frequency from 28.1 to 27.5 kHz. The vibration output from the HPUTs with different mounting systems showed that the transducer with the horn could vibrate the plate at 20 cm from the excitation point, with 300 pm, six times higher than the vibration output from the marinised HPUT. A transducer array and attachment are proposed to make the ultrasound noise below the standard underwater noise limits. The produced sound pressure level (SPL) and sound equivalent level (SEL) from the proposed ultrasonic system was measured. It was specified that the SPL came below 120 dB at 25 m from the excitation point and the SEL value below the 173 dB limit. Finally, the effectiveness of the marinised HPUTS on biofouling removal has been demonstrated with an in-situ measurement, and it was indicated that local biofouling removal could be achieved.
... To some extent, cavitation causes meaningful damage to the pipelines, while high pressures can also cause corrosion in valves and orifices (Fuchs, 2015). At this point, it is suggested to inspect the cavitation device after any treatment declaring any sign of damage. ...
Background: Today, food processing industries are looking for alternative technologies with an eco-friendly character for the processing of food, beverages and agricultural crops. Ideally, such technologies may preserve the original properties of the food products while reaching their primary target of application. Scope and approach: At this point, hydrodynamic cavitation (HC) is recognized as one of the potential technologies for food processing since it provides effective conditions to activate and accelerate desired physiochemical transformations of treated medium. Cavitation phenomenon has been interestingly applied in the treatments and processing of foods towards homogenization (high pressure homogenizers, HPH)/mixing of systems, pasteurization/sterilization, degradation of target molecules, among other purposes. Therefore, this review aims to release the progress in applying HC-assisted technologies for the processing of food, beverages and other food items. Key findings and conclusion: Apart from microorganism inactivation mechanisms in pasteurization and sterilization for foods, emulsion formation in food systems, extraction of bioactive compounds, and improvement of physicochemical properties of food systems are reviewed. Here, the advantages and drawbacks of HC compared to other technologies are also addressed and discussed. To finalize, according to the findings of this review, the future trends, perspectives, and research gaps are also given.
... While for the same treatment time, 1 MHz showed a max of 20% biofilm removal and 2 MHz showed almost no removal. Further studies in the low frequency-range between 10 and 200 kHz are required, as this frequency range is normally used for ultrasonic cleaning of surfaces (Fuchs, 2015;. Ultrasound cleaning efficiency also depends upon the nature of the applied system/surfaces (i.e. ...
In the food industry, equipment surfaces with microbial entities can easily contaminate the food being processed, thereby leading to significant economic problems and even public health issues. To ensure the hygiene of materials in contact with food, cleaning processes are commonly implemented. Conventional strategies used for biofilm removal are energy and water intensive processes. Besides, they also use a substantial amount of chemicals. However, despite the strong enforcement of the conventional cleaning processes, each year, alarming statistics are reported by sanitary organizations, emphasizing the need of improving the safety and hygiene of equipment surfaces. Therefore, the investigation of strategies to effectively remove biofilm biomass is becoming essential. This literature review aims to describe the effectiveness of different physical strategies for biofilm biomass removal. Along with conventional physical methods (conventional CIP, water jet, and static foam cleaning) widely used in the food industry, other promising methods such as pulsed flow, bubble flow, foam flow, ice pigging, snow CO2, electromagnetic methods, plasma, and air jet were reported. Further, the principles, cleaning mechanisms, important process parameters, as well as, limitations associated with these methods have been discussed. All of these methods have shown a promising ability to remove biofilm, while some of them like foam flow and pulsed flow were found to be eco-friendly as they reduced environmental impacts based on LCA analyses.
... A development vector of high-precision mechanisms engineering including 3D printing technologies increases requirements to reliability and resource, mainly due to an industrial cleanliness of surfaces and quality of edge treatment [1][2][3]. Now abrasive technologies are widely used for edge finishing and surface cleaning including various flow abrasive processes [4], and washing, increasingly ultrasonic [5], in spite of the use of abrasives can lead to secondary contamination of surfaces. The use of such technologies is dangerous in the production of high-precision mechanisms due to the remnants of micro-abrasive particles can lead to increased wear or even jamming of friction pairs. ...
The paper refers to the issues of ensuring the quality of Thermal Energy Method (TEM) processing of complex-shaped parts. The required energy of TEM processing depends on the accuracy of the fuel mixture, bearing in mind its component composition, stability and homogeneity. To gain further insight into mixture formation near structural elements of complex-shaped parts a sphere with blind holes having different length-to-diameter ratios were considered. To investigate the effect of the mixture formation in the chamber a numerical simulation for two strategies of filling was conducted, particularly a sequential filling of the chamber with the mixture components and filling the chamber with a prepared mixture of a given composition. A criterion based on the fuel mass fraction distribution was used to assess the quality of the fuel mixture with the possibility of the quality assessment in the individual subareas. The state of the mixture while mutual diffusion of its components and mixing with the residual velocity of gas movement was simulated and the required value of the holding time was determined. Obtained results show that the heterogeneity of the fuel mixture effects significantly the distribution and magnitude of the acting heat fluxes. It is proved that to ensure the degree of the mixture homogeneity required for accurate TEM processing, it is preferable to fill the chamber with the prepared mixture.KeywordsNumerical simulationImpulse Thermal Energy Method
Component compositionHomogeneity of fuel mixture
... This article utilizes the highest bleach concentration recommended by the CDC in the bleach washing procedure to ensure the potential for reusability in medical settings. Furthermore, ultrasonic cleaning induces cavitation bubbles to produce high mechanical forces on the fabric [37] and mechanical stress has been shown to play a dominant role in the removal of silver from fabrics [31]. This paper evaluates fabrics cleaned by ultrasonic cleaning (under ASTM G131-96 standards), which has been shown to achieve better detergency [38]. ...
Medical textiles are subject to particularly harsh disinfection procedures in healthcare settings where exposure risks are high. This work demonstrates a fabric treatment consisting of a reactive silver ink and low surface energy PDMS polymer that provides for superhydrophobicity and antiviral properties against enveloped herpes simplex virus stocks even after extended ultrasonic bleach washing. The antiviral properties of reactive silver ink has not been previously reported or compared with silver nanoparticles. The fabric treatment exhibits high static contact angles and low contact angle hysteresis with water, even after 300 minutes of ultrasonic bleach washing. Similarly, after this bleach washing treatment, the fabric treatment shows reductions of infectious virus quantities by about 2 logs compared to controls for enveloped viruses. The use of silver ink provides for better antiviral efficacy and durability compared to silver nanoparticles due to the use of reactive ionic silver, which demonstrates more conformal coverage of fabric microfibers and better adhesion. This study provides insights for improving the wash durability of antiviral silver fabric treatments and demonstrates a bleach wash durable, repellent antiviral treatment for reusable, functional personal protective equipment applications.
... Ultrasonic cleaning has become more popular since it can remove contaminants and clean difficultly accessible areas (Fuchs, 2015). In this research, we performed cleaning of our 3D-printed ZTLs 3D to assure that the material used (Nylon 12) would not affect the chemical analysis of the collected water. ...
Quantifying and analysing leaching water is essential to understand water and nutrient cycles and the vertical transport of elements through soils. Zero tension lysimeters (ZTLs) have been widely used to capture the soil solution leaching by gravity. This study designed and evaluated a 3D‐printed ZTL (ZTL 3D ) with specific characteristics and materials to quantitatively capture dissolved element fluxes. By 3D‐printing the ZTLs, we were able to include specific 3D structures and precise details in the design allowing installation of samplers from the surface rather than trenches, and thus avoiding the need for installation trenches to remain open. The ZTLs 3D connect directly with the surface, do not depend on secondary collectors, can be installed at any depth, and samplers are easily retractable when dismantling the field set up. The material used, Nylon 12, was tested for dissolved organic carbon (DOC) release. The ZTL 3D design was printed in two different external shapes while characteristics and internal design were identical. The difference in external shape was to study the effects of two contrasting types of installation: a cylindrical sampler for vertical installation (by soil coring from the surface) and a rectangular samplers for horizontal installation (from a pit or a trench wall). We installed them at different depths (2, 30 and 75 cm) in a forest soil and conducted rainfall simulation experiments. A water bucket model (WBM), created to calculate the water drainage fluxes that the ZTLs 3D should collect, reproduced very well the variation in soil water content measured by soil moisture sensors installed adjacent to the ZTLs 3D at 16, 30, 50 and 75 cm depth. Drainage fluxes simulated by the WBM showed that the vertical installation performed better at collecting water at all depths than the horizontal installation, but overall the ZTLs 3D failed to collect the simulated amounts of drainage water. Nonetheless, the ZTLs 3D did collect leachate water, enabling their chemical analysis. Combining the concentrations in the water collected by the ZTLs 3D with the modelled drainage fluxes does allow estimation of DOC‐ and elemental leaching rates. This article presents the novel design of these two types of ZTLs 3D because future improvements may result in better performance, and discusses their (dis)agreement with the modelled WBM fluxes.
Highlights
New 3D‐printed zero tension lysimeters (ZTLs) to capture element fluxes when installed vertically (cylindrical design) or horizontally (cubic design) were tested.
Two external sampler shapes were created to optimise the installation process and both collected drainage water successfully.
Vertical installation ZTLs worked better than horizontal types, but neither well‐reflected drainage fluxes simulated by water bucket model (WBM).
Combined with WBM, both ZTL types provided a reliable method for quantifying nutrient and organic carbon leaching at different soil depths.
... These seminal works have introduced a new field of chemistry called as "sonochemistry" by Neppiras [3]. Large amount of research papers and detailed critical reviews have been published since that time describing different ultrasonic processes, such as cleaning and degassing [4], extraction of biologically active compounds [5], food processing [6,7], advanced oxidation processes [8,9], and synthesis of nanostructured materials [10]. ...
Sonochemistry studies chemical and physical effects in liquids submitted to power ultrasound. These effects arise not from a direct interaction of molecules with sound waves, but rather from the acoustic cavitation: the nucleation, growth, and implosive collapse of microbubbles in liquids submitted to power ultrasound. The violent implosion of bubbles leads to the formation of chemically reactive species. In principle, each cavitation bubble can be considered as a microreactor initiating chemical reactions at mild conditions. In addition, microjets and shock waves accompanied bubble collapse produce fragmentation, dispersion and erosion of solid surfaces or particles. Microbubbles oscillating in liquids also enable nucleation and precipitation of nanosized actinide compounds with specific morphology. This review focuses on the versatile sonochemical processes with actinide ions and particles in homogenous solutions and heterogenous systems. The redox reactions in aqueous solutions, dissolution or precipitation of refractory solids, synthesis of actinide nanoparticles, and ultrasonically driving decontamination are considered. The guideline for further research is also discussed.
... Different conventional methods used to clean such items are brush scrubbing by hand, passing water vapors, stirring in a liquid solution, and spraying the liquid through a nozzle. However, these methods are unable to remove fine dust of micron and submicron size, oily or greasy materials, or any sort of biological contamination trapped between the minute components or built inside the small crevice or holes that are difficult to access [165]. Such items can be cleaned very efficiently by the shear force generated due to ultrasonic waves which eliminate tightly adhered or embedded fine particles on or inside of an object that are inaccessible [166,167]. ...
In this chapter, the application of ultrasound (US) in enhancing different separation processes has been discussed. These processes include crystallization, extraction, demulsification, adsorption, azeotropic distillation, and cleaning of membranes and delicate articles such as jewellery and electronic parts. US is found to intensify these processes with lower energy consumption and without using any toxic chemicals that adversely affect the environment. Additionally, this can be achieved in a noninvasive manner, i.e. without keeping ultrasonic wave‐generating probe into the reactor which avoids the design complexities and cross‐contamination due to contact of process fluid with external accessories and thus makes the process safe. The basic principles of US used for enhancing the specific application in the above‐mentioned processes and its operating parameters have been discussed in detail. The different physical and chemical effects produced during ultrasonication are found to positively affect the performance of these separation processes. The parameters such as US frequency, power, mode (continuous vs. pulsed) of operation and temperature are observed to be the key parameters affecting the separation efficiency. The optimum conditions for these parameters for different applications have been compared and the challenges involved during the operation and scaleup are also discussed. US is found to be explored in depth for enhancing crystallization, extraction, and demulsification followed by desorption and cleaning of membranes, whereas it is at the preliminary stage for azeotropic distillation. US has shown great potential for enhancing these processes. However, still more efforts are needed for successful scaleup at the commercial scale.
... For example, in medicine, the signals created can be used for diagnostic or therapeutic purposes [22,23]. In daily life, the waves can be used for cleaning [24]. In the industrial sector, the acoustic waves generated by a piezoelectric transducer can be used to purify photovoltaic silicon [25]. ...
This paper presents a numerical investigation of the propagation of acoustic waves generated by a linear acoustic source using the lattice Boltzmann method (LBM). The main objective of this study is to compute the sound pressure and acoustic force produced by a rectangular sound source located at the center of the west wall of a rectangular cavity, filled with water. The sound source is discretized into a set of point sources emitting waves according to the acoustic point source method. The interference between the generated cylindrical waves creates an acoustic beam in the cavity. An analytical study is carried out to validate these numerical results. The error between the numerical and analytical calculations of the wave propagation is also discussed to confirm the validity of the numerical approach. In a second step, the acoustic streaming is calculated by introducing the acoustic force into the LBM code. A characteristic flow structure with two recirculating cells is thus obtained.
... Because ultrasonic cleaning efficiency depends on many factors such as cleaning fluid, temperature, standing waves, power, and frequency [16,17], optimized design concerning these factors ensures optimum efficiency. Therefore, from the literature review mentioned above and the authors' experience, it can be concluded that the HRA is more suitable than the structural analysis and modal analysis to achieve higher ultrasonic cleaning efficiency. ...
Several ultrasonic cleaning tanks (UCTs) had a problem: a manufacturer complained that there were damages to cleaning objects, they were unclarified, and it needed to be abruptly solved. To investigate and solve the problem, a small UCT filled with 3.92 L of water, with a frequency of 28 kHz, two horn transducers, and a total power of 100 W was built for simulation and experiment. A built tank body material of UCT can be adjustable to acrylic, glass, and stainless steel. Since the cavitation causing the cleaning relates to acoustic pressure, harmonic response analysis (HRA) in ANSYS software was employed to calculate the acoustic pressure inside the UCT for different designs such as mentioned materials, power, thickness, volume, and frequency. The HRA results revealed uneven acoustic pressure depending on the tank designs, consistent with foil corrosion and power concentration experiments. Furthermore, using the tank body material with acrylic, glass, and stainless steel provided the highest, moderate, and lowest acoustic pressure levels, respectively. The uneven acoustic pressure resulted from the differences in material transmission coefficients. In addition, the damage occurred because of improper tank design, resulting in excessive acoustic pressure. Therefore, the tank design is indispensable in designing high-efficiency UCTs to reduce damage and meet customer requirements.
... Напрямок розвитку високоточних механізмів, включаючи технології 3D-друку, підвищує вимоги до надійності та ресурсу, в основному за рахунок промислової чистоти поверхонь та якості обробки кромок [1,2]. Широко впроваджені технології для обробки кромок та очищення поверхонь, зокрема різні проточні абразивні процеси [3], ультразвукове миття [4], бездеформаційні методи обробки кромок [5], наприклад, електрохімічні [6], електроерозійні [7], лазерні [8], не позбавлені недоліків, наприклад, можуть призводити до вторинного забруднення поверхонь або не забезпечують одночасне поєднання обробки кромки та очищення поверхні. Загальною проблемою для всіх технологій обробки кромок та очищення поверхонь є відсутність автоматизованої системи керування високої точності та спеціальних методів розрахунку режимів обробки з передбачуваною точністю [9,10]. ...
Предметом дослідження є газодинамічний процес сумішоутворення з заданим компонентним складом під час перетікання через змішувач в системі генерації суміші. Метою роботи є науково-експериментальна оцінка технічних рішень змішувача щодо забезпечення точності й гомогенності газової суміші. Завдання дослідження полягають у проведенні числових експериментів перетікання газового потоку через сопла змішувача системи генерації суміші із забезпеченням її стехіометричного компонентного складу й гомогенності. Поставлене завдання розв’язується шляхом створення адекватних математичних моделей газодинамічної течії й аналізу результатів числового моделювання. Отримано такі результати. Розроблено змішувач системи сумішоутворення й дана оцінка технічним рішенням щодо його конструкції. Експериментально встановлені площі прохідного перерізу сопел змішувача. Створено математичну модель процесу генерації суміші із заданим компонентним складом й проведено серію числових експериментів з дослідження перетікання її компонентів через змішувач. Моделювання здійснено з використанням програмного забезпечення ANSYS CFX. Застосовано стаціонарну постановку задачі. В соплах закритичного перетікання змішувача ураховано теплообмін газового потоку зі стінками за рахунок розв’язання задачі і визначення відповідних коефіцієнтів теплопередачі. На входах в змішувач визначено співвідношення початкового тиску компонентів суміші, що забезпечує її стехіометричний склад. Отримані поля швидкостей газового потоку, масову витрату компонентів газової суміші через змішувач, поля тиску й температури. За результатами моделювання встановлено, що конструкція розробленого змішувача забезпечує створення газової суміші зі гомогенністю не нижче 3 %. За умови постійності початкових значень тисків компонентів суміші на вході у змішувач може бути досягнуто стехіометричний склад газової суміші із точністю не нижче 1%.
... However, brushing has limited efficacy in terms of the approachable area for the bristles of the brush. The surface where bristles are unable to reach will not be cleaned (Fuchs, 2015). The antimicrobial efficacy of chemicals is mainly influenced by three factors: concentration, temperature and contact time. ...
Foodborne pathogens could be transferred to food from food contact surfaces contaminated by poor hygiene or biofilm formation. The food processing industry has various conditions favouring microbes' adherence, such as moisture, nutrients, and the microbial inoculums obtained from the raw material. The function of the ideal antimicrobial surface is preventing initial attachment of the microbes, killing the microbes or/and removing the dead bacteria. This review article provides detail about the challenges food industries are facing with respect to food contact materials. It also summarises the merits and demerits of several sanitizing methods developed for industrial use. Furthermore, it reviews the new and emerging techniques that enhance the efficiency of reducing microbial contamination. Techniques such as surface functionalisation, high-intensity ultrasound, cold plasma technologies etc. which have high potential to be used for the decontamination of food contact surfaces are discussed. The emerging designs of antibacterial surfaces provide the opportunity to reduce or eradicate the adhesion of microorganisms. The most important purpose of these surfaces is to prevent the attachment of bacteria and to kill the bacteria that come in contact. These emerging technologies have a high potential for developing safe and inert food contact materials for the food industry.
... Therefore, because the bubble size drops with increasing the ultrasonic frequency and the bubble implosions become less violent, the energy released by each imploding cavitation bubble decreases with the ultrasonic frequency. However, the number of the imploding events increases due to the increased number of sound waves passing through the liquid at a higher frequency [17]. ...
The field of chemical and physical transformations induced by ultrasonic waves has shown steady progress during the past decades. There is a solid core of established results and some topics that are not thoroughly developed. The effect of varying ultrasonic frequency is among the most beneficial issues that require advances. In this work, the effect of sonication of Si wafers in tetrahydrofuran on the photovoltage performance was studied, with the specific goal of studying the influence of the varying frequency. The applied ultrasonic transducer design approach enables the construction of the transducer operating at about 400 kHz with a sufficient sonochemical efficiency. The measurements of the surface photovoltage (SPV) transients were performed on p-type Cz-Si(111) wafers. Sonication was done in tetrahydrofuran, methanol, and in their 3:1 mixture. When using tetrahydrofuran, the enhanced SPV signal (up to ≈80%) was observed due to increasing sonication frequency to 400 kHz. In turn, the signal was decreased down to ≈75% of the initial value when the frequency is lowered to 28 kHz. The addition of methanol suppressed this significant difference. It was implied that different decay processes with hydrogen decomposed from tetrahydrofuran could be attempted to explain the mechanism behind the observed frequency-dependent behavior.
... Acoustic cavitation is the foundation of one of the most sophisticated cleaning methods on the market, [5] "ultrasonic cleaning." Gallego and Graff [6] acutely reviewed this technology and, in agreement with other authors, such as Fuchs, [7] depending on the size of the bubbles and the implosion intensity, a conclusion was drawn that ultrasounds can remove dirt from a surface but also modify the solid surface, or even the liquid itself. In this sense, there are many other applications which can and do benefit from acoustic cavitation, such as surface modification [8], catalysis [9], adsorbent regeneration [10], plant extraction [11], immobilization [12], and nano-emulsification [13]. ...
Ultrasonic cleaning is a developed and widespread technology used in the cleaning industry. The key to its success over other cleaning methods lies in its capacity to penetrate seemingly inaccessible, hard-to-reach corners, cleaning them successfully. However, its major drawback is the need to immerse the product into a tank, making it impossible to work with large or anchored elements. With the aim of revealing the scope of the technology, this paper will attempt to describe a more innovative approach to cleaning large area surfaces (walls, floors, façades, etc.) which involves applying ultrasonic cavitation onto a thin film of water, which is then deposited onto a dirty surface. Ultrasonic cleaning is an example of the proliferation of green technology, requiring 15 times less water and 115 times less power than conventional high-pressurized waterjet cleaning mechanisms. This paper will account for the physical phenomena that govern this new cleaning mechanism and the competition it poses towards more conventional pressurized waterjet technology. Being easy to use as a measure of success, specular surface cleaning has been selected to measure the degree of cleanliness (reflectance) as a function of the process’s parameters. A design of experiments has been developed in line with the main process parameters: amplitude, gap, and sweeping speed. Regression models have also been used to interpret the results for different degrees of soiling. The work concludes with the finding that the proposed new cleaning technology and process can reach up to 98% total cleanliness, without the use of any chemical product and with very low water and power consumption.
... Ultrasonic agitation is a commonly used cleaning process that removes contaminants from surfaces based on cavitation effects. 46 Figure 3f shows that the biofunctionality of the encapsulated antibodies remains >85% after the agitation for 5 min and ∼70% after 30 min. For the unencapsulated antibodies, the retention of the biofunctionality is <50% after 5 min and <5% after 30 min. ...
Point-of-care biosensors are critically important for early disease diagnosis for timely clinical intervention in resource-limited settings. The real-world application of these biosensors require the use of stable biological reagents and cost-effective fabrication approaches. To meet these stringent requirements, we introduce a generic encapsulation strategy to realize ultrastable plasmonic bioink by encapsulating antibodies with organosiloxane polymer through in situ polymerization. Plasmonic nanostructures serve as sensitive nanotransducers allowing for label-free biochemical detection. The plasmonic bioink with encapsulated antibodies exhibits excellent thermal, biological and colloidal stability that are compatible with printing process. As a proof-of-concept, we demonstrate the printability of the ultrastable plasmonic bioinks on different types of substrates with direct writing techniques. The organosiloxane polymer preserves the structure and biorecognition capabilities of the biosensors under harsh conditions, including elevated temperature, exposure to chemical/biological denaturants and ultrasonic agitation. Plasmonic biochips fabricated with the ultrastable ink exhibit superior stability compared to the biochips with unencapsulated antibodies.
... The traditional pesticide cleaning methods, such as washing vegetable with running water and soaking in cleaning water or baking soda solution, could only remove the pesticide contamination on the surface of fruits and vegetables. But in contrast, ultrasonic cleaning could reach the areas that were not easily accessible by using conventional cleaning methods and clean it effectively [41,42]. The implosion of cavitating bubbles caused the shock waves, water jets, and microstreaming, and highspeed water jets impinged to the surface of the samples and removed contaminants J o u r n a l P r e -p r o o f [13,14]. ...
Pyrethroid is widely used in developing countries and is a potential threat to human health. So putting forward an effective pyrethroid cleaning method is of vital importance. Clearance of fenpropathrin, cypermethrin and deltamethrin in cabbage by using ultrasonic treatment accompanied with different baking soda concentrations were investigated in this study. The results of response surface methodology showed that the maximum clearance rate was 70.61% for fenpropathrin under the optimal power, treated time, treated temperature and baking soda concentration, which were 260.02 W, 10 min, 20.15 °C and 0.014 g/mL, respectively. Similarly, the maximum removal efficiency was 73.72% for cypermethrin under 240 W, 13.84 min, 19.53 °C and 0.014 g/mL, and 92.15% for deltamethrin under 238.99 W, 12.42 min, 25 °C and 0.013 g/mL. The clearance rate of pyrethroid by this method was significant higher (P < 0.05) than traditional cleaning methods (bathing and running water washing). The contents of the compositions such as vitamin C, total soluble sugar, protein and dietary fiber, texture and sensory evaluation of cabbage were not found obvious changes after the ultrasonic treatment combined with baking soda (P > 0.05). Results showed that ultrasonic treatment combined with baking soda was an effective way to eliminate the fenpropathrin, cypermethrin and deltamethrin in cabbage without influencing cabbage quality.
... In the pilot-scale study, the ultrasonic bath operated at 1080 W power and a frequency of 26 kHz was found to extract capsaicinoids at higher concentrations than the higher frequency used (70 kHz). As a general rule, increases in frequency lead to reductions in bubble size, which result in decreases in the energy released during bubble implosion [11]. However, higher frequencies also generate a large number of cavitation bubbles, which may also increase the formation of reactive oxygen species [12], and hence destroy oxidation-prone compounds in the extract. ...
The impact of the extraction technologies on product yield and analytical profile is relevant. This review is aiming to discuss recent experiences of successes and failures in non-conventional extraction scaling-up, to better understand the challenges and designing of existing and new techniques. Understanding the crucial extraction factors at laboratory and pilot scale is of paramount value for the engineering work of scaling-up. Besides, a careful analysis and modelling of heat and mass transfer and energy consumption, the design of industrial extraction plants driven by economic and environmental factors, are well covered in the present review. Current trend strongly favors scaling-up of green approaches that consumes less organic solvent(s), involves minimal operational steps, provides high throughput capability and assures highest yield at lower costs. Current and future challenges in scaling-up extraction of bioactive compounds require a parallel development of suitable analytical methods to monitor the process and ensure high yield and quality.
... Ultrasonic cleaning is one of the vital manufacturing processes in various production industries, e.g., rubber, food, electronics, oil, and others, especially jewelry [1,2], as Thailand is one of the world's most important production bases [3]. In the jewelry industry, the shine and gloss of the goods are one of the highest concerns. ...
The manufacturer of an ultrasonic cleaning tank (UCT) received advise from a customer to seek the cause to why the UCT could not clean their products effectively and develop a novel UCT to replace the conventional model. This UCT had a capacity of 10 L, a frequency of 28 kHz, four horn transducers, and a total power of 200 W. To resolve that problem and respond to customers’ needs, we presented new methods to develop the UCT using the harmonic response analysis (HRA) and computational fluid dynamics (CFD) to simulate the cleaning process which occurred within the UCT based on the actual conditions. Results from the HRA showed that the acoustic pressure in a problematic UCT was low, resulting in a smaller cleaning area, which was consistent with the results from the foil corrosion test, and thus caused the cleaning process to be ineffective. We developed a novel UCT with improved effectiveness by adjusting the design and adding a water circulation system. From the HRA, we were able to design the dimensions of the UTC and position of the transducer to be suitable to increase the acoustic pressure and cleaning area. CFD results enabled us to design proper inlet and outlet shapes, as well as simulate the water flow behavior to find the optimal cleaning condition so the novel UCT had a water circulation system that could eliminate the excess particles.
... At constant frequency when the power of ultrasound increases, there is a proportional increase in the number of microbubbles according to law of conservation of energy which demands the more bubbles when sizes of the bubbles are identical. [36,37] These microbubble activities are responsible for increased membrane permeability as a result of transient pore formation on cell membrane. [38] Transient pores help to transfer nonpermeable substrate through the cell membrane by increasing the transmembrane current and eventually enhance cell propagation. ...
Biological molecules are widely produced by fermentation technology using bacteria, fungi or yeast. Fermentation is a biochemical process wherein the rate of bioconversion is governed by the organisms involved. The growth of the organism is mainly limited by mass transfer rates of nutrients and gases that directly affect the product formation in fermentation. Attempts have been made to enhance the growth rate and yield using mutational, recombinant strain development approach at microbial level as well as fed batch and continuous processing approach at bioprocess level in the past. The growth rate of microbes can be accelerated by increased mass transfer rates and cell wall permeability with the use of controlled low frequency ultrasound irradiation. The present review provides insights into the application of acoustic cavitation in process intensification of fermentation approaches and the role of various factors involved are highlighted with typical examples.
... This was due to low-frequency gave stronger effect on cavitation formation [51,52]. It was also reported that as the frequency was increased, the bubble size got smaller and thus energy released by each cavitation implosion was reduced [53]. Vlaisavljevich et al. [54] discovered that the lower frequency would enhance bubble expansion due to the longer rarefactional cycle of the applied pulse. ...
Biodiesel production with 6/2 pulsed ultrasonic single and dual frequencies were conducted under M/O molar ratio (9:1), CaO catalyst (size 200 mesh at 8%wt), time (37 min), intensity (0.91 W/cm2). Powers of waves were 140 W for single waves, and 70W + 70W for dual case. Biodiesel yield for dual frequency case was 96.16% while those of single 28 kHz and 40 kHz cases were 94.42% and 93.60% respectively. The power ratios were varied for the dual cases at 0/140, 20/120, 40/100, 60/80, 70/70, 80/60, 100/40, 120/20 and 140/0 W. The highest yield of 97.13% was obtained at 120/20 W. It was found that lower frequency waves played more important role than higher frequency. Thus, 28 kHz was used as the resonance frequency to determine the resonance size of the catalyst (equal to 49.50 μm). Lastly, biodiesel productions were conducted with 6/2 pulsed dual frequency waves (28 + 40 kHz, 120/20 W) and varying catalyst size as 150, 74, 38, 25 and 18 μm. The 38 μm size gave highest yield of 98.85% due to it was closer to the resonance size compared to the others. Thus using pulsed dual waves with optimal catalyst size can enhance the production yield from 93.60% to 98.85%.
... Ultrasonication is commonly used for cleaning of different materials such as glassware, wafers of semiconductors, and textiles [19]. Ultrasonication has recently been explored for development of magnetic [20], photocatalyst nanomaterials (titania) [21], and nanostructures of layered materials (graphene, vermiculite nanosheets, BN nanosheets, etc.) [22] but it's potential for the development of pure metal powders by top down approach has not been explored yet. ...
Aluminum (Al) nanopowders have potential applications as hydrogen storage medium, energetic materials, pigments, and for production of metal matrix parts via powder metallurgy, to name a few. They are synthesized by methods which are either expensive or result in the product with impurities. A novel methodology based on ultrasonication of commercially available Al foil has been developed for synthesis of Al powders. Al foil was immersed in an organic medium and subjected to ultrasonication in a 160-watt bath ultrasonicator operated at 35 kHz frequency. Morphological, crystal structural, and dimensional characterization of ultrasonicated Al was carried out with the help of scanning electron microscopy (SEM), X-ray diffraction (XRD), and atomic forces microscopy (AFM) respectively. Characterization results revealed that Al foil was eroded laterally as well as axially, resulting in the formation of micro and nanosized flake-like pure Al powder.
... When highfrequency sound waves are transmitted through in an aqueous media, these pressure waves create cavitation bubbles that implode freeing contaminants from their bonds with the implant substrate [116,117]. This cleaning process provides an excellent penetration and cleaning of small and intricate geometries such as the lattice/trabecular structures of patient-specific implants without damaging the substrate [118,119]. For ultrasonic cleaning the selection the appropriate chemical composition of the medium is an critical element no only to speed up the removal rate, but also to achieve a consistent cleaning process to meet production and quality demands [117]. ...
... When highfrequency sound waves are transmitted through in an aqueous media, these pressure waves create cavitation bubbles that implode freeing contaminants from their bonds with the implant substrate [116,117]. This cleaning process provides an excellent penetration and cleaning of small and intricate geometries such as the lattice/trabecular structures of patient-specific implants without damaging the substrate [118,119]. For ultrasonic cleaning the selection the appropriate chemical composition of the medium is an critical element no only to speed up the removal rate, but also to achieve a consistent cleaning process to meet production and quality demands [117]. ...
... However, several studies have already reported inactivation effect of ultrasound power at 20 kHz frequency on various microorganisms [29][30][31]. Moreover, such variables upon the liquid medium (temperature, density, viscosity and surface tension, the number of solid particles, and the amount of dissolved gasses) affect the manifestation and the intensity of cavitation [32,33]. The inactivation effect of ultrasound is related to the cell disruption, alternation of cellular activity owing to cavitation effect and thinning of the cell membrane leading to a change in the cell growth parameters [23,34]. ...
Due to their nonpathogenic status, biosurfactants produced by Lactobacillus strains have been shown to have potential applicability in several industrial sectors, particularly food and pharmaceutical industries. However, products with high efficiency are needed to fulfill the demand for these biosurfactants. Therefore, the present study investigated kinetic parameters, biomass and biosurfactant production of Lactobacillus plantarum ATCC 8014 applying standard MRS and modified MRS (supplemented standard MRS by nitrogen and carbon sources) culture medium under various ultrasonic frequencies of 20, 25, 35, 45, 130 and 950 kHz to obtain more efficient conditions. The optimum conditions were found when using the modified MRS treated by the frequency of 25 kHz (the power of 7.4 W) for 30 min, which led to a significant effect on the growth rate (µmax, h-1) rather than control. Furthermore, this condition caused the highest population (10.07 ± 0.1 log CFU/mL) and biomass concentration (4.33 ± 0.06 g/L), and lowest surface tension (39.26 ± 0.5 mN/m), leading to higher biosurfactant production. Hence, given the results of the present study, it can be established that controlled ultrasound exposure and supplementation of culture media using the main growth factors can intensify the microbial activity and the productivity of biological processes.
... The method is based on applying short, focused, high-pressure ultrasound pulses to generate a cavitation bubble cloud inside the treated tissue. The frequencies used in current clinically approved applications are typically below 1 MHz to further enhance the cavitation, which is inversely proportional to the frequency [97]. Although this technique has shown great potential for treating pathologies such as kidney stones [98] and liver cancer [99], its efficacy is limited to situations in which a single target can be accurately visualized and linearized prior to treatment [100]. ...
Acoustic droplet vaporization (ADV) is the physical process in which liquid undergoes phase transition to gas after exposure to a pressure amplitude above a certain threshold. In recent years, new techniques in ultrasound diagnostics and therapeutics have been developed which utilize microformulations with various physical and chemical properties. The purpose of this review is to give the reader a general idea on how ADV can be implemented for the existing biomedical applications of droplet vaporization. In this regard, the recent developments in ultrasound therapy which shed light on the ADV are considered. Modern designs of capsules and nanodroplets (NDs) are shown, and the material choices and their implications for function are discussed. The influence of the physical properties of the induced acoustic field, the surrounding medium, and thermophysical effects on the vaporization are presented. Lastly, current challenges and potential future applications towards the implementation of the therapeutic droplets are discussed.
... The ultrasound method adds vibrations to the cleaning solution which in turn leads to cavitation. This effect causes bubbles of air to implode on the surface of the part and dis- [34]. ...
Purpose
The purpose of this paper is to introduce a novel technique for printing with multiple materials using the DLP method. Digital-light-processing (DLP) printing uses a digital projector to selectively cure a full layer of resin using a mask image. One of the challenges with DLP printing is the difficulty of incorporating multiple materials within the same part. As the part is cured within a liquid basin, resin switching introduces issues of cross-contamination and significantly increased print time.
Design/methodology/approach
The material handling challenges are investigated and addressed by taking inspiration from automated storage and retrieval systems and using an active cleaning solution. The material tower is a compact design to facilitate the storage and retrieval of different materials during the printing process. A spray mechanism is used for actively cleaning excess resin from the part between material changes.
Findings
Challenges encountered within the multi-material DLP technology are addressed and the experimental prototype validates the proposed solution. The system has a cleaning effectiveness of over 90 per cent in 15 s with the build area of 72 inches, in contrast to the previous work of 50 per cent cleaning effectiveness in 2 min with only 6 inches build area. The method can also hold more materials than the previous work.
Originality/value
The techniques from automated storage and retrieval system is applied to develop a storage system so that the time complexity of swapping is reduced from linear to constant. The whole system is sustainable and scalable by using a spraying mechanism. The design of the printer is modular and highly customizable, and the material waste for build materials and cleaning solution is minimized.
One of the metals used for bone implants is 316L Stainless Steel, which is succesfully coated with hydroxyapatite to increase its low biocompatibility. Therefore, this study aims to carry out sonication, alkali, and heating treatment on 316L Stainless Steel substrates, determine the effect of temperature (A) sonication time (B), acetone concentration (C), bidirectional interaction of sonication temperature and time (AB), bidirectional interaction of sonication time and acetone concentration (BC), bidirectional interaction of sonication temperature and acetone concentration (AC) and the three-way interaction of sonication temperature, time and acetone concentration (ABC), a suitable empirical model for the coating process, and concentration of cleaning solution on the bond strength of the hydroxyapatite layer. The empirical model of the bond strength of the hydroxyapatite layer used was y = 426.1 – 11.50A – 19.25B – 6.229C + 0.6505AB + 0.1944AC + 0.2737 BCE – 0.00933 ABC with an R2 value of 99.49%. The result showed that the layer's bond strength increases with the sonication temperature. It also showed that the longer the sonication time and the acetone concentration, the lower the bond strength value. The highest hydroxyapatite bond strength was produced at a sonication temperature, time, acetone concentration volume and bond strength of 45 °C, 15 min, 99%, and 91.35 Mpa, respectively.
Phase change materials (PCMs) have been considered suitable energy materials to address the mismatch between energy demand and supply to improve the utilization efficiency of the latent heat thermal energy storage (LHTES) system. However, the relatively low thermal conductivity of PCMs leads to an undesirable thermal response rate of the LHTES system. Among the common methods to improve the heat transfer performance of PCMs, the employment of metal foam (MF) has attracted growing attention as an effective strategy. Plenty of studies have investigated thoroughly the vital parameters of MF impacting the phase change process, while a corresponding discussion of the situations and limitations of the known technologies is still lacking. In this review, a total of 476 literature derived since 2000 are visualized based on scientometric analysis to exhibit the attractive spotlights and new trends. The impact factors on the heat transfer performance of PCMs embedded with MF (PCMs/MF) are presented in-depth. Besides, the developments of hybrid heat transfer enhancement techniques based on the MF are overviewed comprehensively. Combined with the thermal characteristics of typical applications, systematic information on PCMs/MF in these applications is summarized, and the suitability of these technologies is discussed. Finally, ongoing challenges of PCMs/MF are identified, and developmental tendencies and opportunities for further research work to address them are discussed. This review provides helpful information to facilitate the development of innovative and feasible PCMs/MF in the LHTES system and encourage and attract researchers and scholars to get some advancement in their future work.
The cleaning of the optical and mechanical components in a high-power laser system is essential for the cleaning control of the high-power laser system. Many factors affect the cleaning efficiency of the solution cleaning. Ion concentration, surfactant concentration and molecular weight of organic molecules are three key factors. In this article, equilibrium and nonequilibrium molecular dynamics simulations are performed to investigate the interfacial interaction among fluid, substrate and oil droplets and the dynamic desorption process of the oil droplet. As the increase of ion concentration, the contact angle of the oil droplet decreases, and the height of the oil droplet decreases slightly. Higher ion concentrations make the oil droplet more hydrophobic because of the reduction in hydrogen bonds between oil droplets and water and the reduction in residual time. In water flow simulation, high ion concentration is not beneficial to the desorption of oil droplets. Pure water flooding is not effective as brine flooding, which is related to water flow velocity. High surfactant concentration is beneficial to the desorption of oil droplets without water flow. Alkane molecule with larger molecular weight is difficult to detach from the solid surface, since the higher interaction energy between alkane molecule and substrate.
In this article, the molecular level investigation on the detachment process of the alkane contaminant from the fused silica surface in nonionic surfactant solution is performed by using molecular dynamics simulation. Three important cleaning parameters including surfactant molecule structure, temperature and surfactant concentration are discussed. We found that the hydrophilic tail of the nonionic surfactant molecule plays a leading role in the desorption process of the oil droplet. The activated chemical activity in surfactant solution with the increasing temperature of solution facilitates the desorption of alkane contaminant. The critical surfactant concentration is vital for cleaning in a real situation. High surfactant concentration can facilitate the desorption of oil droplet in a static solution. The efficiency of water flooding decrease, when the concentration of surfactant is high. Our study can help to understand the cleaning mechanism in surfactant solution and is important for its application in industrial cleaning.
Biofilms are multicellular communities of microorganisms held together by a self-produced extracellular matrix, which contribute to hygiene problems in the food and medical fields. Both spoilage and pathogenic bacteria that grow in the complex structure of biofilm are more resistant to harsh environmental conditions and conventional antimicrobial agents. Therefore, it is important to develop eco-friendly preventive methodologies to eliminate biofilms from foods and food contact equipment. The present paper gives an overview of the current physical methods for biofilm control and removal. Current physical strategies adopted for the anti-biofilm treatment mainly focused on use of ultrasound power, electric or magnetic field, plasma, and irradiation. Furthermore, the mechanisms of anti-biofilm action and application of different physical methods are discussed. Physical strategies make it possible to combat biofilm without the use of biocidal agents. The remarkable microbiocidal properties of physical strategies are promising tools for antimicrobial applications.
During World War I, submarine detection presented a strategic technological challenge, which inspired, among others, the invention of new methods and the employment of a hitherto unused scientific phenomenon. Two prominent physicists, Ernest Rutherford and Paul Langevin, independently suggested the use of this phenomenon: piezoelectricity. Yet they employed it in different ways, leading Rutherford to a useful, if limited, measuring device and Langevin to sonar. Contrary to a claim that is commonly made, Rutherford's work did not lead to sonar. These different results originated on one hand in diverging goals of the two physicists, and on the other in Langevin's more extensive knowledge of and practice with piezoelectricity, which allowed him to manipulate the crystals and contrive the novel ultrasonic design required. Nevertheless, previous encounters with the effect and prior familiarity with it were crucial for its employment by both.
The electronics industry has always had a requirement for a range of metallised dielectric materials to form the conductive tracks used in many electronic products. It is essential that there is excellent adhesion between the dielectric material and the metal or other conductive track since without this failure of the device can occur. Surface modification of the substrate is one way to achieve good adhesion. Traditional wet chemical methods of surface modification employed in electronic manufacturing tend to be very cost effective but use hazardous, oxidizing, corrosive chemistry operate at elevated temperatures (high energy requirements) and require copious rinsing (high water usage). With the introduction of stricter health and safety and environmental legislation it is essential that ‘greener’ methods of surface modification are investigated. A study is currently being carried out evaluating sonochemical surface modification processes on a range of materials used in electronic manufacturing. This work has already shown that some materials can be surface modified using ultrasound through water. However, process times are still relatively long (30–60 minutes) and for the technique to become commercially viable they must be significantly reduced. One way to increase the ultrasonic intensity is to change the solvent and ‘solvent swell’ in a traditional surface modification process that can dramatically improve the adhesion of metal deposited on that material and a number of solvents have been screened. The efficacy of the whole process has been determined using methods such as scanning electron microscopy, contact angle measurements and the determination of adhesion of the plated metal.
Liquid water can be brought beyond the liquid–vapor equilibrium line into a metastable state, before nucleation of bubbles (cavitation) occurs. We review the experimental work on cavitation in water, focusing on the determination of the ultimate degree of metastability at which liquid water can exist. We also present practical applications of metastability and cavitation. To cite this article: F. Caupin, E. Herbert, C. R. Physique 7 (2006).
A new method is described for measuring the cavitation activity in an ultrasonic cleaning system. The method is based on the sonochemical liberation of chlorine from carbon tetrachloride dissolved in water. The chlorine release rate is found to be rapid and linear with irradiation time. The method is used to measure the effect on chlorine release rate of variables such as power input to the transducer, water height, water temperature, and concentration of surfactant in water. The method is also evaluated against the removal of graphite from alumina‐ceramic rings. The result indicates that the chlorine‐release rate has a quantitative relationship with cleaning efficiency. A further comparison of the method and an actual soil‐removal process indicates that a quantitative relationship exists between the chlorine‐release rate and cleaning capability at a given frequency.
This paper presents research results on the electro–thermomechanical behavior of piezoelectric ceramics for use in actuator applications with an emphasis on ferroelectric fatigue. The material being investigated is a lead zirconate titanate piezoelectric ceramic with the composition PbZr0.53Ti0.47O3 (PZT-5H). Results presented in this paper include an augmented constitutive model that accounts for the temperature-dependent piezoelectric properties. Using this model, nonlinear effects measured at one temperature can be extrapolated to other temperatures with good accuracy. Experimental studies into 180° and 90° polarization switching of PZT-5H indicate that the dielectric flux to dipole the material appears to be an adequate criterion for predicting this nonlinear switching behavior. Fatigue studies show that material degradation is strongly influenced by temperature and by the magnitude of the applied electric field. Above a critical temperature, PZT-5H no longer fatigues in the presence of large electric fields due to changes in the electromechanical properties such as the depolarization strain. Using a finite element model incorporating the proposed constitutive relations along with a domain switching criterion, this paper suggests that fatigue degradation is primarily caused by mechanical stresses in the material resulting from spatially variant electric fields causing preferential domain wall motion. The large stress mismatches induce mechanical damage in the form of cracks. © 1998 American Institute of Physics.
The piezoelectric effect and its converse are the primary means used in biomedical ultrasound for converting acoustical energy into electrical energy and vice versa. Piezoelectricity has found many bioengineering applications ranging from ultrasound imaging and therapeutics, to piezoelectric surgery and microelectromechanical systems, and to biomedical implants with associated energy harvesting. Because of its fundamental importance to the proper functioning of most medical ultrasound systems, it is important to gain a general understanding of the effect, the history of its development and from this, an appreciation of its limitations and advantages in the generation and detection of ultrasound. This article describes the historical evolvement associated with its use in relation to most medical ultrasound applications and is intended to serve as an introduction for non-expert readers.
A general review is given of the mechanism of rectified diffusion. The equations that describe the threshold acoustic pressure amplitude as well as the growth rate are presented. Simplified versions of the complicated threshold equation are also obtained for two regions that are of particular interest. Graphical representations of the equations for a variety of physical parameters are given as well as a comparison between the available measurements and the theoretical predictions. Finally, some suggested areas of future research in this area are presented.
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.
Ultrasounds are widely used at industrial scale for cleaning of mechanical pieces for example. Potential applications exist for finishing of textiles. This work aimed to improve traditional textile finishing processes thanks to ultrasound. The technical objective was to develop specific applicators of ultrasonic energy which could be adapted on jigger, a widespread textile finishing machine. Laboratory studies have allowed to define the conditions for application of ultrasounds and check their effects on fibre structure, validated by trials in dynamic conditions. Ultrasound technology makes it possible to intensify the phenomena of diffusion and washing by the effect of cavitation and improves effectiveness of traditional washing treatments. Industrial ultrasound processes need further optimisation on industrial machines.
The generation of ultrasonic cavitation in a thin liquid layer trapped between a large radiating surface and a hard reflector and bounded laterally by a gas-liquid interface is investigated. The theoretical analysis predicts that a large amplification of the acoustical pressure is obtained with this configuration. Experiments are conducted by driving the layer with horn-type transducers having a large emitting surface. Ultrasonic cavitation is obtained in a broad frequency range at low input intensity due to the amplification effect. Erosion tests on metallic foils demonstrate the existence of a region of intense cavitation activity which can be localised by controlling the input intensity.