Duration Of Ultrasonic Treatment Research Articles

A research into the distribution of silicium dioxide nanoparticles in the mixing water

Introduction. The co-authors studied suspensions of silicium dioxide nanoparticles in the water. The application of suspensions helps to most effectively add nanoparticles to slip ceramic mixtures and mixtures that contain concrete. A review of publications has proven that Russian and foreign researchers are willing to learn more about nanoparticles used to modify various materials. Particles having different chemical properties are applied depending on the types of problems to be solved. The method of ultrasonic dispersion of fillers in the matrix material is widely used; surfactants stabilize suspensions and mortars. Silicon dioxide, being one of the cheapest ultra-dispersed powders, has been proven as an active filler designated for building materials.
 Materials and methods. A method of ultrasonic dispersion was used to uniformly distribute nanoparticles in the water. A surfactant was added to the suspension to reduce the reaggregation of particles and to rise the stability of suspensions in the course of time. The turbidimetric method was employed to control the nanoparticle distribution efficiency in the suspension, and a spectrophotometer was used to identify the dimensions of solid particles by measuring the optical density.
 Results. The co-authors have proven the efficiency of the ultrasonic method in distributing nano-sized particles over the water. The suspensions, developed by the co-authors, were used to mold samples of ceramics; a scanning electron microscope and a nozzle, designated for the identification of chemical compositions, were used to identify dimensions of nanoparticle conglomerates in the matrix. The co-authors identified the concentration of OP-10 surfactant that was optimal for the destruction of conglomerates in the suspension; the impact of the ultrasonic treatment duration was assessed in respect of the suspension.
 Conclusions. The research findings can be contributed to ceramic production technologies for versatile nanoparticles to be employed to modify materials.

The effect of ultrasonic treatment on the phase composition of hydroxylapatite synthesized using a hydrothermal technique

The influence of the duration of ultrasonic treatment after hydrothermal synthesis of hydroxylapatite (HA) samples synthesized in the Ca(NO 3 ) 2 ‒(NH 4 ) 2 HPO 4 ‒NH 4 OH precursor system on the phase composition and crystallinity of the synthesized samples is considered. HA samples were investigated using X-ray diffraction and infrared Fourier spectroscopy. The study showed that ultrasonic treatment, regardless of the duration, does not affect the phase composition and crystallinity of the obtained HA samples. In all the studied samples, the presence of the HA phase Ca 10 (PO 4 ) 6 (OH) 2 with a crystallinity of 0,97 was established.

Влияние наночастиц бемита на структурные, коррозионные и диффузионные свойства микродуговых биопокрытий

The results of the morphology, porous structure, the corrosion and diffusion properties study of boehmite-containing calcium phosphate coatings formed by microarc oxidation on titanium substrates are presented. Boehmite nanoparticles obtained as a result of AlN hydrolysis were deposited on the surface of microarc coatings with a developed relief. With an increase in the duration of preliminary ultrasonic treatment (UST) of a suspension with AlN in the range of 20-60 min, the size of agglomerates of boehmite nanoparticles on the coating surface decreases from 200 to 40 μm. The surface porosity of the modified coatings and the area occupied by boehmite particles decrease from 36 to 33% and from 27 to 10% respectively. Agglomerates with boehmite nanoparticles after 60 min of UST of suspensions with AlN powder are distributed more uniformly in the coating than after 20 min of treatment. With an increase in the UST duration of the initial suspensions, the effective diffusion coefficients of the model biological fluid in porous coatings decrease from 7.98·10–11 to 7.25·10–11 m2/s. Modification of calcium phosphate coatings with boehmite nanoparticles with varying the duration of the UST of AlN powder increases the corrosion resistance of the surface layers.

The effect of low frequency ultrasonic treatment on the release of extracellular organic matter of Microcystis aeruginosa

The effect of low frequency ultrasonic treatment on the growth of cyanobacteria and the behavior of extracellular organic matter (EOM) were investigated in this study. The growth of cyanobacteria can be controlled effectively by low frequency ultrasonic treatment, and the inhibitory effect of ultrasound on the photosynthetic ability of cells was more significant than on the cells density (the minimum values of cells density and chlorophyll-a was obtained at day 3 and day 1 respectively). Significant rupture of cells was observed when irradiated by a higher intensity ultrasound (ultrasonic dosage ≥ 1.5 J/mL). Tyrosine-like components were mainly distributed in the soluble EOM and loosely bound EOM fractions; both of the tryptophan-like components and polyaromatic humic-like components were distributed in the soluble EOM, loosely bound EOM, and tightly bound EOM fractions; and polycarboxylate humic-like components were mainly distributed in soluble EOM fraction. Given that the production of hydroxyl radicals was measured, negligible due to the limit of ultrasonic treatment duration (≤1 min). On the other hand, intensive shock waves and shear forces of collapsing acoustic cavitation bubbles were considered as the main reason for the rupture of cells and the changes of the behavior of EOM. A higher intensity ultrasonic treatment resulted in a greater release of EOM, including bound EOM (ultrasonic dosage ≥ 0.1 J/mL), and intracellular organic matter (ultrasonic dosage ≥ 1.5 J/mL). Moreover, the determination of protein and polysaccharide suggested that the bonding of polysaccharides to cells surface is stronger than that of proteins to cells surface, and a portion of the polysaccharides in other fractions was transferred to the tightly bound state during the first serval days after ultrasonic treatment.

Ultrasonic and Heat Treatment of Crude Oils

One of the methods of influence on rheological properties of heavy high-viscosity crude oils is ultrasonic treatment. Ultrasonic treatment allows reducing the viscosity of crude oil and, therefore, reducing the costs of its production and transportation. In this paper, the influence of ultrasonic treatment on the rheological characteristics of crude oil (sample No. 1 API = 29.1, sample No. 2 API = 15.9) was investigated. An experimental method was developed. Experimental studies were carried out using the Physica MCR 102 rheometer. The influence of the intensity and duration of ultrasonic treatment on the viscosity of the initial crude oils was studied for 24 h. In addition, the rheological characteristics of the treated oil were investigated after its natural cooling to 293 K. The results are compared with similar results for thermal heating.

RESEARCH OF THE CHANGE OF THE PRODUCT CONSISTENCE DURING HIS ULTRASOUND PROCESS

This article presents the results of studying the effect of ultrasound on the consistency of products. The task of the study was to identify the possibility of using ultrasound to change the consistency of the product from puree to homogenized. For this purpose, laboratory samples of apple puree were periodically processed on an ultrasonic generator at a frequency of 21.7 kHz, for different duration of exposure to ultrasound from 1 minute to 20 minutes. After processing, measurements of physicochemical parameters were carried out the mass fraction of soluble solids, temperature and viscosity. When analyzing the obtained results, it was found that, depending on the exposure time, the indicators of the mass fraction of dry substances in samples No.1, No.2, No.3 slightly increased relative to the control sample from a value of 11.9 to 12.4 V of sample No.4, in which the duration of exposure to ultrasound was 20 minutes, the indicator of the mass fraction of dry substances increased more significantly up to 13.8%. The same dynamics is observed in the obtained values of the viscosity of the product, which gradually increases in proportion to the exposure time from sample No.1 to sample No.4 (4600-6500 Centipoise (CP)). In addition, a comparative assessment of the organoleptic characteristics of experimental samples (taste, color, aroma and texture) was carried out after their ultrasonic treatment, depending on the duration of exposure. It was found that all the organoleptic characteristics of apple puree with an increase in the duration of ultrasonic treatment with a given parameter at a frequency of 21.7 kHz, changed depending on the time of exposure. Thus, the consistency changed from a “granular” structure (in the control sample) to a homogeneous homogenized (in sample No.3). In sample No.4 (with an exposure time of 20 minutes), mashed potatoes were obtained with a fine, finely divided creamy mass. Consequently, the effect of ultrasound with a given frequency of 21.7 kHz for at least 10 minutes allows a pureed product with a puree-like structure to obtain a homogenized puree.

Сорбционная очистка растворов от ионов тяжелых металлов с применением цеолита, модифицированного углеродными нанотрубками

The processes of heavy metal ions sorption – copper and zinc, with the use of natural zeolite modified by multi-walled carbon nanotubes (MWСNT) with functionalized surface of polar groups (carboxyl, carbonyl, hydroxyl) by ultrasonic action have been investigated. The most effective is the functionalization of the carbon nanotube surface by carbonyl groups (MWСNT–СООН) in the treatment of native MWСNT with a compound of concentrated sulfuric and nitric acids. Carbonyl and hydroxyl groups are also fixated on the surface of nanotubes. The processes of adsorption of zinc and copper ions from solutions on the original and modified zeolite have been studied. For the intensification of sorption processes the application of ultrasonic treatment is the most effective. In this case, the diffusion restrictions in the adsorption layer are removed, the concentration is equalized by mixing the liquid. The dependence of the degree of extraction of ions of zinc and copper from the content of MWCNT–COOH in the zeolite has been studied. At the optimum concentration of 0.1 wt. % MWCNT–COOH, the degree of extraction for zinc is 97.8 %, for copper it is 96.4 %. A further increase in the concentration of nanotubes in zeolite insignificantly increases the degree of extraction. The optimal duration of ultrasonic treatment is 100 s. Under these conditions with the use of unmodified zeolite, the degree of extraction of zinc and copper ions amounts to 72.4 and 68.3 per cent, respectively. Without the influence of ultrasound the results that are close in degree of extraction can be obtained by zeolite treatment of solutions of zinc and copper salts for 2–4 h. The adsorption isotherms at various concentrations of the zinc and copper cations in a solution have been represented, and the basic parameters of the processes have been determined. Modification of zeolite by carbon nanotubes increases the degree of extraction by 20–25 %, the sorption capacity for zinc by 3 times, for copper it increases by 3.5 times. In the case of modification with the use of ultrasonic influence the specific surface of the sorbent increases by 2.3 times. The spent zeolite can be regenerated by treatment with acids for not less than 6 cycles with reduction of extraction degree to 25 %. The scheme of obtaining and sorption purification with the use of modified zeolite by nanotubes has been suggested.

Evolution of the As‐Cast Grain Microstructure of an Ultrasonically Treated Al–2Cu Alloy

The evolution of the grain structure of an Al–2Cu alloy is investigated numerically during its solidification while being subjected to ultrasonic treatment. A CAFE (Cellular Automation Finite Element) model coupling fluid flow, heat transfer, nucleation, and grain growth is developed and validated by comparing the results of both numerical simulations and physical experiments. The model successfully describes hydrodynamic fields generated by ultrasonic treatment and their influence on microstructural evolution. This validated model is then used to study the influence of the duration of ultrasonic treatment on temperature distribution and grain structure. A predominantly equiaxed grain structure developed due to the low temperature gradient throughout the melt is a result of the enhanced convection. These results highlight the critical role played by the convection induced by acoustic streaming during casting, that is, facilitating nucleation and grain growth.

Stabilization of Nanostructured Zeolite Particles: The Effect of Sodium Polyacrylate on the Disaggregation Kinetics and Threshold

The influence of sodium polyacrylate on the disaggregation kinetics and threshold of conglomerates of a natural agromineral, zeolite, under ultrasonic dispersion has been studied. It has been demonstrated that the use of sodium polyacrylate as a stabilizing additive has resulted in the reduction of the zeolite particle size, the increase in the content of isolated fractions, and significant decrease in the ultrasonic treatment duration. When the zeolite was dispersed with sodium polyacrylate, the particles achieved an average size of 750.0 nm after the first minute of cavitation treatment, while the dispersion of the agromineral without the additive required a 5-min treatment to achieve the same result. The use of sodium polyacrylate increased the stabilized state period of zeolite particles to half a year.

Characterization of gelatin from bovine skin extracted using ultrasound subsequent to bromelain pretreatment

Bovine skin was pretreated with bromelain enzyme and ultrasound (53 kHz and 500 W) was used to extract gelatin for the time durations of 2, 4 and 6 h at 60 °C (samples were referred as UB2, UB4 and UB6, respectively). Control (UBC) gelatin was extracted using ultrasound for 6 h at 60 °C without enzymatic pretreatment. Gelatin yield increased significantly (P < 0.05) as the time duration of ultrasound treatment increased with UB6 giving the highest yield of 19.71% followed by UBC (18.67%). Gel strength and viscosity of UBC were 603.24 g and 16.33 mPa s, respectively. The corresponding values for UB6 were 595.51 g and 16.37 mPa s, respectively. The amino acids content increased with longer duration of ultrasonic treatment and UBC exhibited the highest content of the glycine (27.06%) and hydroxyproline (17.21%) compared to other samples. Protein pattern of the gelatin samples showed the progressive degradation of polypeptide chains as the time duration of ultrasound extraction increased. As demonstrated by Fourier transform infrared (FTIR) spectroscopy, amide I band of gelatins extracted by ultrasound treatment exhibited higher wavenumbers than the commercial gelatin (CG) suggesting greater loss of molecular order in these samples. Longer duration of ultrasonic treatment resulted in denser, irregular, disorganized and more interconnected structure with increased porosity as revealed by scanning electron microscopy (SEM) but structural integrity was retained in UBC indicating degradation effect of bromelain enzyme in other samples. Finally, it was concluded that the ultrasound assisted gelatin extraction using bromelain enzyme produced high yield with good quality gelatin.

Sedimentation of suspended solids in ultrasound field

Physical and chemical effects of aquatic environment that occur in an ultrasonic field change the sedimentation rate of coagulated suspension. This might only happen in case of cavitation of ultrasonic filed that causes a change of potentials of the medium. Research of the influence of ultrasonic vibrations on coagulation of suspended solids within water purification allows expanding their scope of implementation. The objective of the research is to estimate the effect of ultrasound on the sedimentation of the suspended solids, to determine of the efficiency of the process in relation to the dose of the coagulant, and to calculate the numerical values of the constants in the theoretical equation. The experiment condition was held in the water with the clay substances before the introduction of the coagulant. The method of magnetostriction ultrasonic generator was applied to receive ultrasonic vibration. Estimate of concentration of clay particles in water was performed using photometry. As a result of the research, the obtained data allow determining the increase in efficiency of suspended particles sedimentation related to the dose of coagulant, depending on time of ultrasonic treatment. The experiments confirmed the connection between the effect of sedimentation in the coagulation process, the coagulant dose and the time of scoring. Studies have shown that the increase in the duration of ultrasonic treatment causes a decrease of administered doses of coagulant.

Sedimentation of suspended solids in ultrasound field

Physical and chemical effects of aquatic environment that occur in an ultrasonic field change the sedimentation rate of coagulated suspension. This might only happen in case of cavitation of ultrasonic filed that causes a change of potentials of the medium. Research of the influence of ultrasonic vibrations on coagulation of suspended solids within water purification allows expanding their scope of implementation. The objective of the research is to estimate the effect of ultrasound on the sedimentation of the suspended solids, to determine of the efficiency of the process in relation to the dose of the coagulant, and to calculate the numerical values of the constants in the theoretical equation. The experiment condition was held in the water with the clay substances before the introduction of the coagulant. The method of magnetostriction ultrasonic generator was applied to receive ultrasonic vibration. Estimate of concentration of clay particles in water was performed using photometry. As a result of the research, the obtained data allow determining the increase in efficiency of suspended particles sedimentation related to the dose of coagulant, depending on time of ultrasonic treatment. The experiments confirmed the connection between the effect of sedimentation in the coagulation process, the coagulant dose and the time of scoring. Studies have shown that the increase in the duration of ultrasonic treatment causes a decrease of administered doses of coagulant.

High-energy ultrasound to improve the quality of purifying the particles of iron ore in the process of its enrichment

The iron-magnetite raw material extracted in Ukraine is characterized by a complex texture, structure, and a high content of harmful impurities such as silicon dioxide, potassium oxides, sodium, magnesium, and sulfur. At the same time, the requirements for the quality of iron ore concentrates entering the further metallurgical processing are increasing, as the high quality of magnetite concentrates can significantly reduce the cost of metallurgical production. Meanwhile, the quality of concentrates decreases mainly due to the formation of technogenic micron splices in the iron ore pulp. The main reason for the formation of gaps is the presence of ion-electric and molecular fields on the surface of the ore particles. The formation of technogenic gaps reduces the difference in the properties of the surface of the ore and nonmetallic grains; it changes their magnetic susceptibility and, consequently, the efficiency of separation methods. Analysis of the results of studying the influence of the dynamic effects of high-energy ultrasound on the ore pulp showed the promising use of this approach. To improve the efficiency of cleaning the surfaces of minerals, it is proposed to pre-treat the iron ore slurry with the help of high-energy ultrasound. The optimum values of the intensity and the duration of ultrasonic treatment in the purification of mineral particles have been determined. When cleaning mineral particles, the intensity should be 1.2 W/cm 2 , and the processing time should not exceed 60 seconds. In this case, the yield of the purified product is increased by 0.8 %, and its quality grows by 0.9 %. It has been proven that the efficiency of ultrasonic treatment is associated with the renewal of particles surfaces, which leads to an increase in the contrast of magnetic and flotation properties of minerals. The study has shown that ultrasonic treatment of the iron ore pulp in the Kremenchuk iron ore region of Ukraine allows reducing the content of harmful impurities: potassium oxide – from 0.19 to 0.035–0.04 %; sodium oxide – from 0.14 to 0.027 %.

Extraction of flavonoids from Chrysanthemum morifolium and antitumor activity in vitro.

The aim of the present study was to optimize flavonoid extraction from Chrysanthemum morifolium and to study the antitumor effects of flavonoids on human gastric cancer MKN45 cells in vitro. A single factor experiment was designed and the extraction process was optimized using an orthogonal test. MKN45 cells were treated with different concentrations of flavonoid from Chrysanthemum morifolium for 24 and 48 h and the inhibitory effect on the MKN45 cells was evaluated using an MTT assay. Following staining with Annexin V-fluorescein isothiocyanate/propidium iodide, flow cytometry was performed. The optimized flavonoid extraction conditions were as follows: Duration of ultrasonic treatment: 35 min; ethanol concentration: 75%; extraction temperature: 80°Cand liquid-to-solid ratio 25: 1. Under the above conditions, the extraction rate of flavonoids was 5.24%. When compared with a blank control group, flavonoids extracted from Chrysanthemum morifolium inhibited the proliferation of MKN45 cells in a dose- and time-dependent manner. Furthermore, in cell groups treated with low, moderate and high concentrations of flavonoid, it was observed that the proportion of apoptotic cells increased in a dose-dependent manner. The extraction process optimized by the orthogonal test achieved a high yield and satisfactory extraction efficiency. Additionally, the experiment demonstrated that flavonoids from Chrysanthemum morifolium inhibited the growth of MKN45 cells and induced their apoptosis. Thus, flavonoids from Chrysanthemum morifolium exerted antitumor effects on MKN45 cells, which may be exploited as a potential antitumor therapeutic for gastric cancer.

Formation and Properties of Nickel–Phosphorus–Graphite Composite Coatings in Autocatalytic Deposition

It is shown that nickel–phosphorus–graphite composite coatings can be deposited by the autocatalytic deposition method. The optimal concentration of graphite and the duration of ultrasonic treatment of a graphite suspension in solution for deposition of composite coatings based on the nickel–phosphorus alloy were determined. The influence exerted by thermal treatment parameters on the properties of the deposits was examined. The optimal process conditions are suggested.

Simulation of convective flow and thermal conditions during ultrasonic treatment of an Al-2Cu alloy

Grain refinement of an Al-2Cu alloy using ultrasonic treatment was investigated numerically. A finite element model coupling fluid flow and heat transfer was developed and validated by comparing the results of both numerical simulations and physical experiments. The model successfully describes hydrodynamic fields generated by ultrasonic treatment and its influence on heat transfer. The simulations were used to study the influence of the duration of ultrasonic treatment and the associated acoustic streaming on convection and the resulting temperature distribution. It was revealed that a relatively cold sonotrode applied during ultrasonic treatment for up to 4 min created a casting environment that promoted crystal nucleation and enabled their growth and survival during transport of these grains into the bulk of the melt by strong convection. The enhanced convection established a low temperature gradient throughout the melt which favours the formation of an equiaxed grain structure. Therefore, the convection induced by acoustic streaming plays a critical role in facilitating nucleation, growth, and transport of grains.

Dispersion of carbon nanomaterials in an aqueous medium using a triton X-100 surfactant

The “solubility” of carbon nanotubes (CNTs) in the aqueous solution of a Triton X-100 surfactant has been measured. It has been shown that the dependence of the “solubility” of CNTs on the surfactant concentration has an extremal character and that the maximum “solubility” of CNTs at the optimum concentration of the surfactant obeys the equation S max = (0.35–0.40)C CNT 0 (C CNT 0 is the ratio of the mass of the charge to the volume of the aqueous solution of the TX-100). The ratio of S max to the surfactant concentration is 0.4–0.5. The maximum fracture of CNTs that pass into the dispersion is equal to 1.8–2.0% of their total amount in the system. An increase in the duration of ultrasonic treatment increases the maximum “solubility” of the CNTs to 2.7 mg/mL. According to the preliminary results, the value of S max in the presence of Triton X-100 in the case of graphenes reaches 1.0 mg/mL; and in the case of the carbon nanospheres, 1.8 mg/mL.

Effects of ultrasonication on the production of hyaluronic acid by lactobacilli

The oral administration of hyaluronic acid has been shown to improve skin health. This study aimed at utilizing ultrasound treatment to enhance the production of hyaluronic acid by lactobacilli. Among the 16 strains of lactobacilli screened, a higher production of hyaluronic acid (P<0.05) was observed from seven strains namely, Lactobacillus casei BT 2113, Lactobacillus casei BT 1268, Lactobacillus casei BT 8633, Lactobacillus casei FTDC 8033, Lactobacillus acidophilus FTDC 1231, Lactobacillus gasseri FTDC 8131 and Lactobacillus rhamnosus FTDC 8313. Upon ultrasonic treatment, hyaluronic acid concentration increased significantly (P<0.05) in all the seven strains studied. The use of ultrasonication at 100% amplitude increased the hyaluronic acid content (P<0.05) up to 51.6 % with concentrations ranging from 0.262 mg ml−1 to 0.385 mg ml−1, while an amplitude of 20% yielded a lower increase ranging from 0.227 mg ml−1 to 0.310 mg ml−1. Increasing duration of ultrasonic treatment (from 1 min to 3 min) also significantly (P<0.05) improved the concentration of hyaluronic acid in some strains. Our data demonstrated that a sub-lethal physical treatment, such as ultrasonication, can be applied to increase the membrane permeability of lactobacilli cells and subsequently increase the release of bioactive metabolites.

Effect of Ultrasonication Duration on Colloidal Structure and Viscosity of Alumina–Water Nanofluid

Nanofluids are promising fluids for heat-transfer applications. Low stability and high viscosity are two important drawbacks for practical applications of nanofluids. The aggregation and sedimentation of nanoparticles are related to the colloidal structure of nanofluids, which directly affects the stability and viscosity. An ultrasonic homogenizer can break the aggregation of particles. The aim of this work was to study the effect of the duration of ultrasonic treatment on colloidal structure, including the stability and temperature-dependent viscosity of a nanofluid. Specifically, a 0.5 vol % Al2O3–water nanofluid was prepared using an ultrasonic homogenizer for various durations from 0 to 180 min. The microstructure, colloid and particle sizes, precipitation, and zeta (ζ) potential were analyzed to investigate the aggregation and sedimentation of the nanofluid. The viscosities of nanofluids subjected to ultrasonic treatment for different durations were also measured at different temperatures from 15 to ...

Influence of Ultrasonication Parameters on Physical Characteristics of Olive Oil Model Emulsions Containing Xanthan

Ultrasonic emulsification of 20-wt.% o/w emulsions (pH 3.8) containing a food-grade emulsifier (whey protein isolate, WPI, 2.7 wt.%) and xanthan gum (XG, 0.25 wt.%) was performed. Time and amplitude of ultrasonic treatment changed in order to evaluate their influence on emulsion droplet size, viscosity, and stability (by multiple light scattering (MLS) profiles) during cold storage (10 days at 5 °C). Ultrasonic treatment duration changed from 1 to 4 min at constant amplitude of 70 %. Considering the amplitude, intervals of 40, 60, 80, and 100 % were chosen, for a constant time of 1 min. Similarly, time and amplitude conditions were used to treat solutions of XG of 1 wt.% and evaluate their influence on viscosity and how that was related to the stability of the emulsion. Increase in sonication time from 1 to 4 min led to a significant oil droplet size decrease from 1.14 to 0.89 μm (median droplet diameter). The viscosity of emulsions and XG solutions was highly influenced and considerably decreased with sonication time applied. At those conditions, an increase of backscattering was observed from 58.9 to 72.7 % after 10 days of storage, meaning that more stable emulsions, thinner and of smaller oil droplet size were produced. A similar trend was observed when the amplitude was increased, but droplet size and creaming were always greater than those noticed by changing the sonication time. However, the rate of viscosity, droplet size, and stability change was greater by increasing the amplitude rather than by changing the sonication time.