Cavitation Effect Of Ultrasound Research Articles

Copper Single-Atom-Based Metal-Organic Framework for Ultrasound-Enhanced Nanocatalytic Therapy.

Chemodynamic therapy (CDT) is an emerging therapeutic modality triggered by endogenous substances in the tumor microenvironment (TME) to generate reactive oxygen species. However, the mild acid pH, low H2O2 concentration, and overexpressed glutathione can suppress the CDT efficiency. Herein, ultrasound (US)-triggered Cu2+-based single-atom nanoenzymes (FA-NH2-UiO-66-Cu, FNUC) are constructed with the performance of target and glutathione depletion. In the TME, the single-atom Cu sites of FNUC consume glutathione and the FNUC:Cu+ generates •OH via peroxidase-like activity. The US-activated FNUC exhibits a fast •OH generation rate, a low Michaelis constant, and a large •OH concentration, indicating the cavitation effect of US promotes the •OH generation. Meanwhile, the tumor target of FNUC is confirmed by NIR-II fluorescence imaging, in which it is modified with IR-1061. Combined with the antitumor performance of FNUC in vitro and in vivo, the novel Cu-based SAzymes can achieve efficient and precise cancer treatment.

Accelerated sonochemical fabrication of MIn2S4 (M = Zn, Mg, Ni, Co) for ultra-high photocatalytic hydrogen peroxide production

Ternary metal sulfide (MIn2S4) by virtue of large extinction coefficient, suitable band gap and stability, has been proposed as a candidate for photocatalytic synthesis hydrogen peroxide (H2O2). However, MIn2S4 is conventionally synthesized by solvothermal method that is generally characterized by tedious operational steps and long reaction time. In this work, four sonoMIn2S4 (M = Zn, Mg, Ni, Co) were successfully prepared by sonochemical method within 2 h. These as-synthesized sonoMIn2S4 delivered much high-efficient photocatalytic H2O2 generation. Particularly, the sonoZnIn2S4 presented H2O2 production rate of 21295.5 μmol∙g−1∙h−1 in water/benzylalcohol system, which is 3.0 times that of ZnIn2S4 prepared by solvothermal method. The remarkably improved photocatalytic performance of sonoZnIn2S4 might be due to the multiple defects and fast electron-hole pair separation caused by ultrasound cavitation effect. Other metal sulfide photocatalysts with high performance were efficiently fabricated by facile sonochemical technology as well. The sonochemical method realized the rapid preparation of metal sulfide photocatalysts and efficient production of H2O2, which benefits to meet the United Nations Sustainable Development Goals (SDGs) including SDG-7 and SDG-12.

Effect of ultrasonic vibration treatment on microstructure evolution and mechanical properties of Cu-TiB2 composites

The distribution of second-phase particles is crucial to the mechanical properties of particulate reinforced copper matrix composites (PRCMCs). Ultrasonic vibration treatment (UVT), as an effective technique to disperse second-phase particles in metallic melts, has been extended to treat PRCMCs using a SiAlON sonotrode. In this study, systematic experiments have been conducted to explore the effect of UVT on the microstructures and mechanical properties of in situ Cu-TiB2 composites. The results indicated an optimal duration of UVT for 3 min, featured by an improved distribution of TiB2 particles and superior mechanical properties of the as-cast composite. The ultimate tensile strength, yield strength, and elongation exhibited significant increases of 15.7%, 18.1%, and 36.1%, respectively, compared to the as-cast Cu-TiB2 composite without UVT. Furthermore, these experimental composites were subject to rolling deformation. The results once again demonstrated that the as-rolled Cu-TiB2 composite, treated with UVT for 3 min, stood out as the best. The ultimate tensile strength, yield strength, and elongation of the as-rolled Cu-TiB2 composite were 459 MPa, 422 MPa, and 7.0%, respectively. Based on the microstructural observation, the mechanism underlying the UVT-induced enhancement of mechanical properties was discussed in terms of the non-linear effects of ultrasound cavitation on liquid metals. This work can provide a strategy for producing high-performance PRCMCs through UVT.

A clean and efficient route for extraction of vanadium from vanadium slag by electro-oxidation combined with ultrasound cavitation

Extracting vanadium (V) from vanadium slag (VS) by the traditional roasting-leaching process has disadvantages of high energy consumption and high poisonous gases emission. In this work, a green and efficient route was developed to extract V from VS without roasting by electro-oxidation combined with ultrasound cavitation (EOUC) intensification in sulfuric acid solution. The leaching parameters (e.g., leaching temperature, sulfuric acid concentration, anodic current density, ultrasound power, liquid to solid ratio, leaching time and particle size) were optimized. The leaching mechanism was explored by comparing the leaching behavior and mineralogical evolution of the direct sulfuric acidic leaching (DSL), electro-oxidation-assisted sulfuric acidic leaching (EOSL), ultrasound cavitation-assisted sulfuric acidic leaching (UCSL) and EOUC methods. The results show that introducing electric field strengthens the ultrasound cavitation effect on slag particles in sulfuric acid solution. Under the optimum parameter of EOUC method, the leaching rate of V from VS is as high as 94.64 %. Using EOUC method can open the silicate-wrapped structure of the spinel, increase pore volume of VS from 0.00127 cm3 g−1 to 0.01124 cm3 g−1, decrease slag particle size from 26.8 μm to 16.4 μm and improve specific surface area from 0.508 m2 g−1 to 10.855 m2 g−1, which significantly accelerate V leaching process. The exposed spinel was oxidized by both electrochemical route and chemical route, forming a mixture of V3+ ion and VO2+ ion after leaching.

Achieving Fast Charge Separation by Ferroelectric Ultrasonic Interfacial Engineering for Rapid Sonotherapy of Bacteria-Infected Osteomyelitis.

Bacteria-infected osteomyelitis is life-threatening without effective therapeutic methods clinically. Here, a rapid and effective therapeutic strategy to treat osteomyelitis through ferroelectric polarization interfacial engineering of BiFeO3 /MXene (Ti3 C2 ) triggered by ultrasound (US) is reported. Under US, the ferroelectric polarization induces the formation of thepiezoelectric field. US cavitation effectinduced sonoluminescence stimulates BiFeO3 /Ti3 C2 to produce photogenerated carriers. With synergistic action ofthepolarization electric field and Schottky junction, BiFeO3 /Ti3 C2 accelerates the separation of electrons and holes and simultaneously inhibits the backflow of electrons, thus improving the utilization of polarized charges and photogenerated charges and consequently enhancing the yield of reactive oxygen species under US. As a result, 99.87 ± 0.05% of Staphylococcus aureus are efficiently killed in 20min with the assistance of ultrasonic heating. The theory of ferroelectric ultrasonic interfacial engineering is proposed, which brings new insight for developing ferroelectric ultrasonic responsive materials used for the diagnosis and therapy of deep tissue infection and other acoustoelectric devices.

In-situ synthesis of TiB2 particulate reinforced copper matrix composites with ultrasonic vibration treatment

In this paper, ultrasonic vibration treatment (UVT) was directly introduced into Cu-Ti-B melt through a Sialon sonotrode. The effects of UVT on the microstructures and properties of TiB2/Cu composite thus fabricated were investigated. The results indicate that with the application of UVT, the average size of the particle agglomerates in the as-cast composite reduced from 24.84 μm to 19.69 μm. Besides, the 3D morphology of the agglomerates changed from irregular to near-spherical under the effect of ultrasound cavitation. The acoustic streaming promotes the flow of the melt to realize a more uniform distribution of particles in the bulk. Dispersion of TiB2 particles alleviates the stress concentration caused by coarse agglomerates, resulting in the concurrent improvements in both strength and ductility of the composite.

Synergistic effect and mechanisms of ultrasound and AlOOH suspension on Al hydrolysis for hydrogen production

Ultrasound can accelerate and change the reaction process and is widely used in the field of hydrogen production and storage. In this study, ultrasound (US) and AlOOH suspension (AH) are used to promote hydrogen production from Al hydrolysis. The results indicate that both US and AH greatly shorten the induction time and enhance the hydrogen production rate and yield. The promoting effect of US and AH on Al hydrolysis originates from the acoustic cavitation effect and catalytic effect, respectively. When AH is used in combination with US, Al hydrolysis has the best hydrogen production performance and the hydrogen yield can reach 96.6 % within 1.2 h, because there is a synergistic effect on Al hydrolysis between AH and US. Mechanism analyses reveal that the micro-jets and local high temperature environment arising from acoustic cavitation improve the catalytic activity of AlOOH, while the suspended AlOOH particles enhance the cavitation effect of US. This work provides a novel and feasible method to promote hydrogen production from Al hydrolysis.

Effect of Ultrasound Cavitation versus Electroacupuncture on Sex Hormones in Obese Infertile Women with Polycystic Ovarian Syndrome: A Randomized Controlled trial

Effect of Ultrasound Cavitation versus Electroacupuncture on Sex Hormones in Obese Infertile Women with Polycystic Ovarian Syndrome: A Randomized Controlled trial

Optimization of the Sustainable Production of Resistant Starch in Rice Bran and Evaluation of Its Physicochemical and Technological Properties.

In this study, the optimization of ultrasound (US) (850 kHz, 120 W) processing parameters (temperature, time, and power) for the enhanced production of resistant starch (RS) in rice bran (RB) matrixes was performed. The effect of US cavitation at different temperatures on the morphology, physicochemical properties, and mechanical performance of RS was evaluated. Ultrasonication at 40–70 °C temperatures affected the chemical structure, reduced the crystallinity of RS from 23.85% to between 18.37 and 4.43%, and increased the mechanical and thermal stability of RS pastes, indicating a higher tendency to retrograde. US treatment significantly (p < 0.05) improved the oil (OAC) and water (WAC) absorption capacities, swelling power (SP), solubility (WS), and reduced the least-gelation concentration (LGC). The mathematical evaluation of the data indicated a significant effect (p < 0.05) of the US parameters on the production of RS. The largest increment of RS (13.46 g/100 g dw) was achieved with US cavitation at 1.8 W/cm2 power, 40.2 °C temperature, and 18 min of processing time. The developed method and technology bring low-temperature US processing of rice milling waste to create a new sustainable food system based on modified rice bran biopolymers.

Synergistic Effect of Ultrasound Cavitation and Gas in the Water Disinfection

The paper considers water purification processes from Bacillus bacteria type under the conditions of gases bubbling only (argon, helium, oxygen, and carbon dioxide), cavitation and combined action of gas and cavitation. The synergistic effect was found under conditions of simultaneous action of gas and cavitation (kd(gas/US ) &gt;kd(gas) + kd(US) almost double) and it was shown that kd(gas/US) &gt;kd(gas) by almost an order of magnitude. Relative series of effective destruction of microbial cells was established: Ar/US &gt; О2/US &gt;Не/US &gt; СО2/US. Destruction degree of the cells reaches 70 %at the short-term Ar/US exposure (~8 min), which is 7 times more active than cavitation action and 13.5 times more than bubbling of Aralone.

Topical delivery of gambogic acid assisted by the combination of low-frequency ultrasound and chemical enhancers for chemotherapy of cutaneous melanoma

Anti-cutaneous melanoma activity of the skin-delivered gambogic acid (GA) has been reported in our previous study. However, it is difficult for GA to diffuse passively through intact skin without any enhancement means. In this study, a combination of chemical enhancers (EN: azone and propylene glycol) and physical ultrasound (US) was used to improve the percutaneous permeation of GA and enhance the anti-melanoma activity. The enhancement effect of the combination of EN and US (EN-US) on GA in vitro and in vivo was studied, and the enhancement mechanism and skin irritation were also evaluated. We showed that the parameters of US application at a constant frequency (30 kHz) with a duty cycle of 100% and intensity of 1.75 W/cm2 for 20 min were optimal. In vitro, EN-US showed a considerable enhancement of the permeation of GA, and the enhancement effect was stronger than that with the use of EN or US alone. In vivo antitumor study showed that the tumor growth was significantly inhibited after percutaneous administration of GA by EN-US, more than in the intravenous injection group. The penetration enhancement mechanism revealed that EN-US not only altered the structure of lipid bilayers and keratins to reduce the barrier effect of the stratum corneum but also produced diffusion channels in the skin under the cavitation effect of US, thereby promoting the skin penetration of GA. In addition, there was no observable skin irritation in mice after treatment with EN-US. Our study demonstrated that the combination of EN and US improved the skin permeation and retention of GA to enhance the anti-melanoma activity. This method also provides technical guidance for the future development of topical and transdermal therapeutic system of GA.

Abstract 1318: Mechanochemical dynamic therapy for focal cancer treatment

Abstract This study proposes a new cancer drug delivery modality that allows for spatiotemporal control over activation of the therapeutic. Current standard cancer therapies of surgery, chemotherapy, and radiation therapy have their limitations, such as invasiveness and systemic toxicities. Developing a new modality that is localized and triggerable is becoming increasingly advantageous. Currently, photodynamic therapy (PDT) has been shown to be clinically effective but is limited by poor tissue penetration of light. Sonodynamic therapy (SDT) bypasses this pitfall with increased tissue penetration depth of ultrasound. However, PDT has limitations as it relies on the potentially damaging ultrasound cavitation effect and requires sonosensitizers or nanoparticles that have issues with bioavailability, biostability, and biosafety. In this study, we propose a novel ultrasound-based cancer treatment modality called mechanochemical dynamic therapy (MDT). In MDT, high intensity focused ultrasound (HIFU) delivers mechanical forces to force-responsive moieties of azo mechanophores that are embedded into biocompatible polyethylene glycol (PEG) hydrogel polymers. Upon focal sonication with HIFU, these mechanophores generate highly reactive free radicals (FRs) that are converted to reactive oxygen species (ROSs). The sonicated gels are then placed into in vitro cultures, allowing for the diffusion of ROSs into the cells to induce oxidative cytotoxicity and eventually cell death. Cell proliferation is monitored at 24-hour intervals, and by 72 hours, the sonicated gels produced cell killing effects comparable to lethal doses of H2O2 in both in vitro mouse melanoma (B16F10) and breast cancer (E0771) models. Sonication of control hydrogels that did not contain mechanophores showed minimal cytotoxicity. This study shows the potential of MDT as a drug delivery platform that overcomes the limitations of PDT and SDT and has the potential to be applied synergistically with other current cancer treatments. This is the first demonstration of using HIFU-activated mechanophores to non-invasively deliver cancer therapies with spatiotemporal control. Citation Format: Gun Kim, Qiong Wu, James L. Chu, Emily J. Smith, Michael L. Oelze, King C. Li, Jeffrey S. Moore. Mechanochemical dynamic therapy for focal cancer treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1318.

Air-backed photoacoustic transmitter for significantly improving negative acoustic pressure output

Aiming to pursue an ultrasound signal with a significantly improved negative acoustic pressure level, which is one of the critical characteristics for exciting the ultrasound cavitation effect, a real applicable air-backed photoacoustic transmitter is presented. Different from the conventional solution of relying on a complicated focusing structure design, it works based on an acoustic signal phase reversal and amplitude superposition strategy. By using an innovative sandwich-like suspending photoacoustic layer with optimized structure design, the initial backward-propagating positive sound pressure can be converted into the forward-propagating negative one efficiently. For proof-of-concept demonstration, photoacoustic transmitter prototypes adopting a polydimethylsiloxane (PDMS)/candle soot nanoparticle/PDMS-PDMS composite as a photoacoustic conversion layer were fabricated and characterized. From experiment results, an acoustic signal with a remarkable ratio of negative pressure level to a positive one of 1.3 was successfully realized, which is the largest value ever reported, to the best of our knowledge. Moreover, when compared to the commonly used glass and PDMS-backing conditions in the photoacoustic area, nearly 200% and 400% enhancements in negative pressure output were achieved, respectively.

The effect of ultrasound cavitation on endothelial cells.

Acoustic cavitation has been widely explored for both diagnostic and therapeutic purposes. Ultrasound-induced cavitation, including inertial cavitation and non-inertial cavitation, can cause microstreaming, microjet, and free radical formation. The acoustic cavitation effects on endothelial cells have been studied for drug delivery, gene therapy, and cancer therapy. Studies have demonstrated that the ultrasound-induced cavitation effect can treat cancer, ischaemia, diabetes, and cardiovascular diseases. In this minireview, we will review the impact of ultrasound-induced cavitation on the endothelial cells such as cell permeability, cell proliferation, gene expression regulation, cell viability, hemostasis interaction, oxygenation, and variation in the level of calcium ions, ceramide, nitric oxide (NO) and nitric oxide synthase (NOS) activity. The applications of these effects and the cavitation mechanism involved will be summarized, demonstrating the important role of acoustic cavitation in non-invasive ultrasound treatment of various physiological conditions.

Use of high-power ultrasound combined with supercritical fluids for microbial inactivation in dry-cured ham

The aim of this study was to analyze the application of supercritical carbon dioxide combined with high-power ultrasound (SC-CO2 + HPU) and the use of a saline solution (SS; 0.85% NaCl) on the microbial inactivation and the quality of dry-cured ham. The effect of temperature, pressure and treatment time was studied using RSM. Physicochemical analyses were carried out after the treatments and during refrigerated storage (30 days / 4 °C). The most significant inactivation of Escherichia coli (3.62 ± 0.20-log CFU/g) was obtained using the SC-CO2 + HPU + SS (25 MPa, 46-°C and 10-min), with temperature being the most important process variable. Fat content showed a significant (p < 0.05) reduction (46%) after the SC-CO2 + HPU treatment. The breakage of the muscle fibers, the disorganization in the myofibrils, as well as the enlargement of the interfibrillar spaces led to the ham softening (avg 26.5%). No significant (p > 0.05) changes in color, texture or pH were found during storage. Thus, ultrasonic-assisted SC-CO2 could be used, in combination or not with SS, to improve the shelf of dry-cured ham. Industrial relevanceSupercritical carbon dioxide (SC-CO2) inactivation technology has been shown to be highly efficient at reducing different bacteria in liquid media with minimum effect on food quality. This technology is barely applied to solid products and its use is limited by the long processing times and reduced inactivation capacity. The application of high-power ultrasound (HPU) leads to a shorter process time. This technology is useful for the inactivation of ham microbiota and inoculated E.coli. A liquid medium surrounding the treated solid can enhance microbial inactivation for the purposes of improving the effect of ultrasound cavitation, while only minimally affecting the quality of the samples (color, texture, fat and moisture contents).

The effect of ultrasound cavitation in combination with cryolipolysis as a non-invasive selective procedure for abdominal fat reduction

Background and aimFat reduction and body contouring have become popular procedures in the cosmetic surgery industry over the past decade. There have been studies to replace invasive methods such as liposuction, with safer non-invasive procedures. We aimed to evaluate the effect of a non-invasive combination therapy of ultrasound cavitation and cryolipolysis on abdominal adipose tissue. MethodsThis pilot interventional study comprised 90 female individuals aged 18-65-years-old who were recruited into one of three groups of 30 participants. Group 1 was treated with diet alone (the control group), group 2 with cryolipolysis and diet, and group 3 with a combination of ultrasound cavitation, cryolipolysis, and diet for 8 weeks. Anthropometric parameters were measured before, during, and after the trial included total body weight, body mass index(BMI), body fat mass, fat-free mass, and abdomen circumference. ResultsAll three groups demonstrated significant reductions in each parameter at the end of the intervention (P < 0.01). Apart from fat-free mass (P = 0.66), the combination therapy significantly reduced body fat mass, weight, BMI, and abdomen circumference compared to the control group (P < 0.01). There was no significant difference between the combination therapy and cryolipolysis-alone groups. ConclusionTreatment using a combination of cryolipolysis and ultrasound cavitation is no more effective in improving the anthropometric indices than cryolipolysis alone.

Design of Intravascular Ultrasound-enhanced Thrombolysis Excitation System Based on FPGA

An intravascular ultrasound-enhanced thrombolysis excitation system with adjustable frequency, amplitude and duty cycle was designed based on FPGA (ZYNQ-7Z020). Firstly, the FPGA generated waveform amplitude binary data based on direct digital frequency synthesis (DDS) technology, and then the data was converted into burst signal through an external daughter card, which included D/A conversion circuit, active low-pass filter, power amplifier circuit and impedance matching circuit. The test results demonstrated that the output waveform reached the target with advantages of simple implementation and flexible control, the peak negative pressure generated from ultrasound transducer was doubled by means of an electrical impedance matching network. In vitro thrombus models were applied to verify the excitation system, it turned out that ultrasound cavitation effect generated could accelerate the penetration of urokinase and increase the thrombolysis rate by about 20%.

Effect of Ultrasound Cavitation on Weight Reduction for Prediabetic Obese Patients

AbstractBackground: Obesity has received considerable attention as a major health hazard and can be an underlying cause of many disorders such as type 2 diabetes.Aim of Study: The purpose of present study is to investigate the effects of ultrasound cavitation on weight reduction for prediabetic obese patients.Design: Randomized control trial design.Subjects: Fifty patients prediabetic obese women from the out clinic of Faculty of Physical Therapy of Deraya University, Minia, Egypt. They were randomly assigned into two groups, each group twenty-five patients.Patients and Method: Group I (control group): Twenty-five patients were received aerobic exercises and low caloric diet, three times per week for twelve weeks. Group II (exper-imental group): Twenty-five patients were received aerobic exercise, ultrasound cavitation and low caloric diet treatment, twice weekly ultrasound cavitation sessions for six weeks, and aerobics exercise three times per weeks for twelve weeks. (Bщ WHR, skin fold, fasting blood sugar level, post prandial blood sugar level and HbA1c level) were measured before treatment (pre-test data), and after the completion of the treatment program, as a post-test measurement.Results: There was a statistical significant effect of ultra-sound cavitation to low calorie balanced diet and treadmill exercise on reduction in weight, Bщ WHR, skin fold, fasting blood glucose level, post prandial blood glucose level and HbA1c level in prediabetic obese female patients.Conclusions: Adding Ultrasound cavitation to low calorie balanced diet and treadmill exercise could be utilized as physical therapy program design for treatment to prediabetic obese female patients.

Ultrasound Cavitation Versus Cryolipolysis on Central Obese Patients

AbstractBackground: Central Obesity is one of the most common worldwide diseases afflicting humans. It is a major health problem throughout the world because of its high prevalence and its association with increased risk of cardiovascular and liver diseases.Aim of the Study: Was to determine the effect of ultrasound cavitation versus cryolipolysis on central obese patients.Subjects: Thirty (30) patients of both sexes, 15 men and 15 women. They were assigned into two groups equal in number. Their ages ranged from 45 to 55 years. Group A with mean age (50.47±3.31) years and Group B with mean age (49.47±3.89) years.Methods: Body Mass Index (BMI), Waist Circumference (WC) and abdominal fat percentage was measured before and after performing ultrasound cavitation and cryolipolysis sessions in both groups. Group A patients received ultrasound cavitation sessions for one month (8 sessions/patient), Group B patients received cryolipolysis sessions for one month (one session/patient).Results: The results revealed that there was statistically significant reduction in central obesity (BMI, abdominal fat% and WC) in both Group A and Group B. But there wasn't statistically significant reduction in central obesity (BMI, abdominal fat% and WC) between two groups. There was improvement in Group B than Group A. In Group A, the percentage of improvement for BMI, abdominal fat% and WC was 2.94%¯, 11.07%¯ and 5.59%¯, respectively. In Group B, the percentage of improvement for BMI, abdominal fat% and WC was 3.62%¯, 19.11%¯ and 4.68%¯ respectively.Conclusion: There was improvement in central obesity after applying ultrasound cavitation and cryolipolysis sessions with mild better results in cryolipolysis than ultrasound cavitation.

Coupling Ultrasound to the Electro‐Oxidation of Methyl Paraben Synthetic Wastewater: Effect of Frequency and Supporting Electrolyte

AbstractIn this paper, electrooxidation of methyl paraben (MeP) is studied by electrolysis only and electrolysis coupled with sonolysis, using a diamond electrode. Complete mineralization of MeP was achieved for both processes, in chloride and sulfate media. Results showed that, although the oxidation of pollutant is faster in the presence of chloride, the mineralization is favored in sulfate medium. Ultrasound irradiation enhanced the removal of organic matter due to the activation of oxidant species in both supporting electrolytes. Moreover, the formation of chlorine gas in the chloride containing medium improves the ultrasound cavitation effect, promoting faster depletion of the total organic carbon in the first hour of treatment. Regarding the formation of more toxic products, all possible organochlorinated intermediates were removed, since complete mineralization was attained in less than 5 hours. Ultrasonic coupling to the electrolysis process accelerates the destruction of the intermediates and delays the formation of perchlorate, which only begins after the complete removal of the total organic carbon. Low and high ultrasound frequencies were evaluated and were found to produce different effects of cavitation, which affect the electrolysis in different ways. The final result will be a balance between these effects and thus, an optimum frequency can be established for different systems.