Effect Of Ultrasonic Cavitation Research Articles

Ultrasonic enhanced water washing method for extracting sodium fluoride from spent pot lining

A large amount of spent pot lining (SPL) is produced by cryolite-alumina melting electrolysis process, and the fluoride content in the leaching solution is up to 6000 mg/L, which belongs to hazardous waste. If SPL is not handled effectively, it will cause great harm to the environment. Because the NaF rich in SPL is an important raw material for the synthesis of cryolite by carbonation, this paper uses SPL as the raw material to extract NaF. On the basis of exploring the process conditions of water washing leaching NaF, ultrasonic wave was introduced to enhance mass transfer and the effects of ultrasonic cavitation on water washing process was compared. The results show that ultrasonic waves can effectively shorten the time for water washing to reach equilibrium and further improve the efficiency of NaF leaching. Under the optimal process conditions determined by the experiment, when the ultrasonic power is 400 W, the time for washing to reach equilibrium is shortened from 50 min to 40 min, and the NaF leaching efficiency is increased from 67.25 % to 70.42 %. While improving the leaching efficiency, the water consumption is effectively reduced, and the purity of the recovered product NaF is 96.82 %. This research provides a technical reference for the harmless and low cost leaching of NaF from SPL in the aluminium electrolysis industry.

Taping into the super power and magic appeal of ultrasound coupled with EDTA on degradation of 2,4,6-TCP by Fe0 based advanced oxidation processes

Chlorophenol is a widely used organic compound, and the environmental and health problems caused by it have being worsened in recent years. This study used 2,4,6-trichlorophenol (2,4,6-TCP) as the target pollutant, and employed ultrasound (US) enhanced zero-valent iron (Fe0)/EDTA/air system (FEA), namely US/FEA, to remove 2,4,6-TCP. The influence of single factor experimental conditions such as EDTA concentration, Fe0 dosage, US power, pH and pollutant concentration on the removal efficiency of 2,4,6-TCP was investigated, and the optimal reaction conditions were determined. The mechanism of reactive oxygen species (ROS) produced by US/FEA was explored. The degradation process and removal mechanism of 2,4,6-TCP in the US/FEA were discussed through the determination and analysis of intermediate products. The results showed that US could continuously activate and renew the Fe0 surface, accelerate its oxidation and corrosion process, and then continuously and stably produce sufficient amounts of Fe2+ and Fe3+. Ultrasonic cavitation effect could reduce the difficulty of O2 activation reaction, and promote the production of sufficient H2O2. The addition of EDTA made the system have a wide range of pH applications, and its performance under neutral and alkaline conditions was also superior. The ROS of US/FEA included ·OH, O2·- and Fe(IV), where Fe(IV) was the main contributor to the removal of 2,4,6-TCP. In addition, the degradation of 2,4,6-TCP had two processes including dechlorination and benzene ring opening. First, 2,4,6-TCP was dechlorinated and degraded into phenol. And then, phenol was degraded into small molecular acids by ring-opening, and finally it was mineralized into CO2 and H2O completely. US/FEA is a promising technology for high-efficiency degradation of organic matter and deep environmental purification.

Erosion characteristics and failure mechanism of reservoir rocks under the synergistic effect of ultrasonic cavitation and micro-abrasives

Ultrasonic cavitation erosion of reservoir rocks in distilled water with and without SiO2 micro-abrasives (mean diameter 0.5 μm, mass concentration 1–7 wt%) are conducted. The erosion characteristics of eroded rocks are measured and analyzed. Both the area of cavitation damage zones and the surface roughness are increased when rocks are eroded in water-abrasive mixture. Compared with distilled water, the mass loss in 3 wt% water-abrasive mixture has improved by 69.66–104.23% (average 81.41%) for sandstone, 495.05–665.15% (average 557.38%) for shale, and 158.49–211.92% (average 188.16%) for granite during an erosion time of 5 ∼ 60 min. The promoted erosion can be explained by the synergistic effect of cavitation and micro-abrasives. The failure mechanisms are elucidated for different types of rocks. The erosion of reservoir rocks results from the peeling-off of mineral grains and the breakdown of large mineral crystals. Numerous micro-fractures and pores are produced in the surface of the eroded rocks, creating additional permeable channels for fluid flow. The results demonstrate that the presence of micro-abrasives can increase the ultrasonic cavitation erosion of reservoir rocks, indicating that the addition of micro-abrasives is feasible to enhance the performance of ultrasonic treatment for oil wells in petroleum industry.

Effect of cavitation bubble on the dispersion of magnetorheological polishing fluid under ultrasonic preparation

In the ultrasonic dispersion process, the ultrasonic cavitation effect can seriously affect the dispersion efficiency of magnetorheological polishing fluid (MRPF), but the mechanism remains unclear now. Through considering the continuity equation and Vand viscosity equation of the suspension, a revised cavitation bubble dynamic model in the MRPF was developed and calculated. The effects of presence or absence of solid particles, the volume fraction of solid particles, and viscosity on the cavitation bubble motion characteristics in the MRPF were discussed. Settlement experiments of the MRPF under ultrasonic and mechanical dispersion were observed. Analysis of particle dispersion is made by trinocular biomicroscope and image processing of the microscopic morphology of the MRPF. The results show that the high volume fraction of carbonyl iron particle (CIP) will significantly weaken the cavitation effect, and the low volume fraction of green silicon carbide (GSC) has a negligible effect on the cavitation effect in the MRPF. When the liquid viscosity is greater than or equal to 0.1 Pa·s, it is inconvenient to produce micro-jets in the MRPF. The sedimentation rate of the MRPF prepared by ultrasonic dispersion is lower than mechanical dispersion when the volume fraction of CIP is between 1% and 25%. The dispersion ratio under ultrasonic dispersion is lower than that under mechanical dispersion. The experimental results fit the simulation well. It offers a theoretical basis for exploring the ultrasonic cavitation effect in the industrial application of the MRPF.

Cavitation Effect in Ultrasonic-Assisted Electrolytic In-Process Dressing Grinding of Nanocomposite Ceramics.

Ultrasonic-assisted electrolytic in-process dressing (UA-ELID) grinding is a promising technology that uses a metal-bonded diamond grinding wheel to achieve a mirror surface finish on hard and brittle materials. In this paper, the UA-ELID grinding was applied to nanocomposite ceramic for investigating the cavitation effect on the processing performance. Firstly, the ultrasonic cavitation theory was utilized to define the cavitation threshold, collapse of cavitation bubbles, and variation of their radii. Next, the online monitoring system was designed to observe the ultrasonic cavitation under different ultrasonic amplitude for the actual UA-ELID grinding test. A strong effect of ultrasonic cavitation on the grinding wheel surface and the formed oxide film was experimentally proved. Besides, under the action of ultrasonic vibration, the dressing effect of the grinding wheel was improved, and the sharpness of grain increased by 43.2%, and the grain distribution was dramatically changed with the increase of ultrasonic amplitude. Compared with the conventional ELID (C-ELID) grinding, the average protrusion height increased by 14.2%, while the average grain spacing dropped by 21.2%. The UA-ELID grinding reduced the workpiece surface roughness Rz and Ra by 54.2% and 46.5%, respectively, and increased the surface residual compressive stress by 44.5%. The surface morphology observation revealed a change in the material removal mechanism and improvement of the surface quality by ultrasonic cavitation effect. These findings are considered instrumental in theoretical and experimental substantiation of the optimal UA-ELID grinding parameters for the processing of nanocomposite ceramics.

Half-Time Heat Map Reveals Ultrasonic Effects on Morphology and Kinetics of Amyloidogenic Aggregation Reaction.

Ultrasonication has been recently adopted in amyloid-fibril assays because of its ability to accelerate fibril formation, being promising in the early stage diagnosis of amyloidoses in clinical applications. Although applications of this technique are expanding in the field of protein science, its effects on the aggregation reactions of amyloidogenic proteins are poorly understood. In this study, we comprehensively investigated the morphology and structure of resultant aggregates, kinetics of fibril formation, and seed-detection sensitivity under ultrasonication using β2-microglobulin and compared these characteristics under shaking, which has been traditionally adopted in amyloid-fibril assays. To discuss the ultrasonic effects on the amyloid-fibril formation, we propose the half-time heat map, which describes the phase diagram of the aggregation reaction of amyloidogenic proteins. The experimental results show that ultrasonication greatly promotes fibril formation, especially in dilute monomer solutions, induces short-dispersed fibrils, and is capable of detecting ultra-trace-concentration seeds with a detection limit of 10 fM. Furthermore, we indicate that ultrasonication highly alters the energy landscape of an aggregation reaction due to the effect of ultrasonic cavitation. These insights contribute not only to our understanding of the effects of agitation on amyloidogenic aggregation reactions but also to their effective application in the clinical diagnosis of amyloidoses.

The enhanced effect of collapse strength of a dual-frequency driven bubble in 2-dimensional space

The bubble-collapse strength is closely related to the ultrasonic cavitation effect. The enhanced effect of collapse strength of a dual-frequency driven bubble is one of the mechanismsunderlying the synergistic effect of dual-frequency excitation. In this paper, the growth rate of bubble-collapse strength is defined as:G=(Rmax,d′-Rmax,s′)/Rmax,s′, where Rmax,s′and Rmax,d′are the bubble maximum oscillation radius under single- and dual-frequency exciting, respectively. The enhanced region I (below the main resonances line), II (above the main resonances line) and III (around the diagonal line) concerning to the bubble-collapse strength in f1-f2 plane are analyzed. The results show that the enhanced effect of bubble-collapse strength is implicated in the acoustic pressure, bubble equilibriumradius and pressure amplitude ratio. This paper could be helpful for optimizing the dual-frequency operation from the perspective of bubble radial dynamics.

Mutual-reinforcing sonodynamic therapy against Rheumatoid Arthritis based on sparfloxacin sonosensitizer doped concave-cubic rhodium nanozyme

Rheumatoid arthritis (RA) is an autoimmune disease associated with synovitis and cartilage destruction. Ultrasound (US)-driven sonodynamic therapy (SDT) possess a good application prospect in RA therapy because of its non-invasiveness and strong tissue penetration capabilities, which can kill activated synovial inflammatory cells. Nevertheless, the tiny accumulation of sonosensitizers in the joints and the hypoxic synovial microenvironment severely limit the therapeutic effect of SDT. Hence, we developed a sonosensitizer spafloxacin (SPX) doped and human serum albumin (HSA) loaded concave-cubic rhodium (Rh) nanozyme (Rh/SPX-HSA) to realize mutual-reinforcing SDT during ultrasonic activation. On the one hand, SPX would cause mitochondrial dysfunction by inducing excessive reactive oxygen species (ROS) production, thus suppressing fibroblast-like synoviocyte (FLS) under US conditions. On the other hand, concave-cubic rhodium was utilized as a nanozyme with endogenous peroxidase (POD) and catalase (CAT)-like enzyme activities, which not only relieved the hypoxia of the joint to resist angiogenesis, but also enormously ascended the SDT efficacy by rising 1O2 levels. Interestingly, the activity of nanozymes was also improved by the ultrasonic cavitation effect, thereby realizing mutual-reinforcing SDT. Overall, our strategy provided Rh-based to achieve effective SDT under hypoxic microenvironment, which offered a promising prospect for highly efficient treatment of RA.

The effects of Ozonation and ultrasonic cavitation on batik wastewater treatment with coagulation-flocculation as pre-treatment

The batik industry produces large volumes of wastewater with high organic content. Dyes in batik wastewater are difficult to degrade by biological processes. Therefore, further processing is needed to reduce pollutants before being released into the environment. This study aims to observe the performance of the ultrasonic cavitation, ozonation, and combination of ozonation/ultrasonic cavitation to treat batik wastewater, which was first given a coagulation-flocculation pre-treatment with Polyaluminium Chloride (PAC) coagulants. The variations applied were ultrasonic intensity (20%, 30%, and 60%) and pH of wastewater (4, 7, and 10). In this study, it was found that the combination of the ozonation/ultrasonic cavitation method with a pH of 4 and ultrasonic intensity of 20% produced the best performance, namely COD, TSS, and color (Pt-Co) removal of 77.02%, 95.15%, and 94.88%. The ultrasonic intensity and initial pH of wastewater played an important role in the performance of the treatment process. In the ultrasonic cavitation method with an ultrasonic intensity of 20%, the highest percentage of COD, TSS, and color (Pt-Co) removal was 65.59%, 91.51%, and 93.41%. The ozonation method in acidic conditions (pH 4) produced a better performance with COD, TSS, and color (Pt-Co) removal of 70.51%, 94.35%, and 96.10% for 60 minutes.

ULRASONIC CAVITATION IN TREATMENT OF TROPHIC UICERS

The aim: improvement of trophic ulcer by surgical treatment with ultrasound cavitation combination.
 Materials and methods. The analysis of complex surgical treatment of trophic ulcers was conducted. Patients were divided into 2 groups, depending on the strategy of treatment. In the first (main) group (n=43) the combination of surgical treatment with ultrasonic cavitation was applied. By comparison, in the second group (n=43) only surgical treatment was applied. The method of treatment of trophic ulcers with the Sonoca 300 device is based on the effect of ultrasonic cavitation, which is a process of mechanical cleaning of the wound from necrotic tissues, while healthy tissue and vessels are not injured. Ultrasound machine SONOCA 300 is intended exclusively for use in human ultrasound surgery and is intended for the following applications: selective tissue dissection, mechanical grinding and cutting of bone tissue, debridement and cleaning of wounds, tissue cutting, tissue coagulation. The exact purpose of the application is determined by which tool is connected. In our case, this is a Macro ultrasonic tip designed for debridement and wound cleansing. Ultrasound is supplied at an operating frequency of 25 kHz, when you press the foot pedal, and simultaneously with the power of ultrasound, the irrigation and aspiration systems are activated. The irrigation solution from the container with the irrigation fluid passes through the tool, at the same time the aspiration of necrotic tissues and fluid, and their direction into the container for aspirate collection.
 Results and discussions. The ultrasonic cavitation in treatment of trophic ulcers different localization and etiological factors, achieve partial incarnation of ulcer surface on the average in (14,2±0,5) days in the first group and in (16,9±0.6) days in the second group.
 The level of bacterial titer of ulcer secretion by (16,5±0,6) days was not higher than the commonly accepted critical one in comparison to the classic situation, in the second group it was on the (27,2±0,9) days. Terms of inpatient treatment were: (21,2± 0,9) days in the first group and (27,2±0,9) days in the second group accordingly. The biological properties of ultrasound are due to bactericidal and bacteriostatic action on various microorganisms. In addition to its own bactericidal effect, low-frequency ultrasound significantly enhances the action of many antibiotics and antiseptics, promotes the deposition of drugs in the surface layers of the wound. Under the action of ultrasound increases the phagocytic activity of leukocytes, there is a stimulation of cellular and humeral parts of the immune system, which accelerates the wound process.
 Conclusion. The usage of ultrasonic cavitation in the complex surgical treatment of trophic ulcers different localization and etiological factors, significantly increases the time of trophic ulcer cleaning, accelerates incarnation by 1.2, reduce the time of treatment of patients with trophic ulcers by 1.8 times in comparison to the classical approach of cleaning, by means of mechanical cleaning of the ulcers from purulence and necrotic tissue by ultrasound of low frequency.

Cavitation effect in two-dimensional ultrasonic rolling process

The ultrasonic cavitation effect can improve the machining quality. In order to study the formation process of cavitation in two-dimensional ultrasonic rolling process (TDUR) and its influence on processing, a simulation and experimental study of cavitation in TDUR was conducted to further improve the processing quality. The pressure distribution model and the cavitation model of the two-phase mixed flow around the roller in TDUR were constructed by combining the ideal bubble dynamics theory. And the cavitation intensity was evaluated by the vapor volume fraction (VVF). The formation process of cavitation effect in the flow field was analyzed by finite element analysis, and the effects of different inlet pressures and different pipe structures on the cavitation were studied. TDUR experiments were carried out to study the changes of surface roughness and residual stress of the workpiece under the effect of ultrasonic cavitation, and the positive effect of cavitation effect was verified. The simulation results show that the cavitation effect mainly occurs in the left half of the roller and the rolling area, and the cavitation in the left half of the roller changes from transient cavitation to steady-state cavitation as the inlet pressure increases. Different inlet pressures in the rolling region always show periodic transient cavitation, with obvious cavitation bubbles generation, expansion and collapse processes. The lower the inlet pressures in the straight and inverted trumpet pipe, the stronger the transient cavitation effect. The experimental results show that the cavitation effect can further improve the surface strengthening quality of the workpiece. Under the same process parameters, the surface roughness of the workpiece can be reduced by up to 47.7% and the residual compressive stress of the surface can be increased by up to 10.2%. Therefore, the cavitation effect can be applied in ultrasonic rolling process to further improve the surface strengthening quality, and the straight pipe at atmospheric inlet pressure is preferred in TDUR.

INFLUENCE OF THE IMPACT OF ACOUSTIC CAVITATION ON THE PHYSICAL AND CHEMICAL PROPERTIES OF WATER

The article presents the results of an experimental study of the changing the ionic composition of water under the influence of acoustic cavitation. The effect of acoustic radiation on the physical and chemical properties of water was studied in the frequency range 20 Hz - 50 kHz. It is shown that the ultrasonic range leads to an increase in the concentration in the area of metal traces and affects the change in the pH of water. The mechanism of action of cavitation leads to a change in the structural characteristics of water. It is shown that one of the manifested effects of ultrasonic cavitation can be used for various applications.

Microstructure evolution and properties of direct laser deposited 24CrNiMoY alloy steel assisted by non-contact ultrasonic treatment

To solve the problems of high porosity and uneven microstructure of high-performance alloy steel parts, 24CrNiMoY samples were prepared by non-contact ultrasonic cavitation-assisted (UC-A) direct laser deposited (DLD) process. The samples in the UC-A DLD process were treated with ultrasonic application at three angles of 30°, 45°, and 60° to the horizontal plane and without ultrasonic treatment. The ultrasonic frequency and amplitude were 40 kHz and 30 μm, respectively. The laser energy density of the deposited samples was 83.3 J/mm2. Characterization tests such as OM, XRD, SEM, EBSD, TEM, hardness, wear and tensile tester were performed to study the structural evolution and mechanical properties of the samples under different ultrasonic treatments. The results showed that the microstructure of the prepared samples were a large amount of lath bainite (LB) and a small amount of granular bainite (GB), and the introduction of ultrasound could significantly reduce the porosity in the sample. When the angle of ultrasonic application was 60°, the dense sample with fine-grained and better mechanical properties was obtained. With the ultrasonic application angle increased to 60°, the average strip width of LB was reduced from 34.9 μm to 14 μm, and the grain size of alloy sample was decreased from 0.87 μm to 0.47 μm. The average microhardness, wear loss, tensile strength, and elongation of the samples treated with ultrasonic application angle of 60° were 381.97 HV0.2, 1.0×10-3 g, 1125.1 MPa, and 11.5%, respectively, which increased by 10.6%, 33.3%, 31.7%, 88.5% compared with the sample untreated. Finally, the evolution mechanism between the angle of ultrasonic application and the pores in 24CrNiMoY alloy steel sample was established, and the effect of ultrasonic cavitation on the microstructure and performance of the samples were analyzed through the experimental procedure. Therefore, it is an effective method to reduce porosity, refine microstructure, and improve the mechanical properties of DLD 24CrNiMoY alloy steel by applying non-contact UC-A with a proper application angle (60°).

The mechanism of ultrasound oxidation effect on the pyrite for refractory gold ore pretreatment

The effect of ultrasonic cavitation on the oxidation of the crystal pyrite in deionized water has been discussed. The effect of solution alkalinity, ultrasonic power and temperature on the surface morphology of pyrite and the chemical forms of sulfur and iron was discussed. The surface of pyrite is severely corroded under ultrasound. The sulfur in the pyrite is oxidized to S2O32- and SO42-. Most of the iron is in the form of Fe2+, few of it is in the form of Fe3+. With the increase of alkalinity, ultrasonic power and temperature, the surface corrosion of pyrite becomes more and more obvious. With the increase of the NaOH concentration, the Fe(II) concentration in solution decreases and the deposition of iron oxides on the pyrite surface prevents pyrite oxidation. With the increase of the ultrasonic power, the Fe(II) concentration in solution increase. The effect of the NaOH concentration on the SO42- and S2O32- concentration indicates pyrite oxidation is in mild alkalinity under ultrasound. The concentration of SO42- and S2O32- increases along with increase of the ultrasonic power and decreases tremendously with increase of the temperature. The pyrite oxidation is initiated by hydroxyl radical and promoted by Fe3+.

Enhancement of catalytic activity in NH3-SCR reaction by promoting dispersibility of CuCe/TiO2-ZrO2 with ultrasonic treatment

A series of CuCe-modified TiO2-ZrO2 catalysts synthesized by stepwise impregnation method and ultrasonic-assisted impregnation method were investigated to research the removal of NO in the simulated flue gas. Results showed that the CuCe/TiO2-ZrO2 catalyst prepared by ultrasonic-assisted impregnation method exhibited the superior NO conversion, in which higher than 85% NO was degraded at the temperature range of 250–400 °C and the highest NO conversion of 94% at 350 °C. It proves that ultrasonic treatment can markedly improve the performance of catalysts. The effect of ultrasonic enhancement on CuCe/TiO2-ZrO2 was comprehensively studied through being characterized by physicochemical characterization. Results reveal that the ultrasonic cavitation effect improves the distribution of active species and the synergistic interaction between Cu with Ce components (Cu+ + Ce4+ ↔ Cu2+ + Ce3+) on the catalysts significantly, thus resulting in better dispersibility as well as a higher ratio of Cu2+ and Ce3+ of the catalysts. Moreover, it was found that the CuCe/TiO2-ZrO2 catalyst prepared by the ultrasonic-assisted impregnation method represented a higher degree of ultrafine metal particles and evenness. The above results were described with the generalized dimension and singularity spectra in multifractal analysis and validated by the comparative test. Therefore, it can be concluded that ultrasonic treatment facilitates the particle size and distribution of active sites on the catalysts.

Design of deicing device for wind turbine blade based on microwave and ultrasonic wave

Nowadays, wind turbine deicing has become a hot research topic. The traditional deicing method of blade has many problems, such as high energy consumption, low efficiency and low effect. In order to solve the above problems, the project team designed a wind turbine blade deicing device based on microwave and ultrasonic wave. During the operation, two deicing methods, namely microwave thermal energy, ultrasonic cavitation effect and thermal effect, were used to deice in stages to achieve the purpose of high efficiency and energy saving. The whole device is composed of walking system, microwave system and ultrasonic system, and the operation of the device is realized by the electrical control part. Compared with the existing deicing methods, the device can achieve the purpose of low energy consumption and high efficiency Deicing; in addition, the device has the advantages of flexible mechanism for control, less pressure on wind turbine blades, and low cost.

Ultrasonic Spray Chemistry: In-Situ Synthesis of Thin-Film Conjugated Microporous Polymers and Their Energy Storage Applications

Conjugated microporous polymers (CMP) are potential energy storage materials owing to their rigid and cross-linked microporous structures. However, the fabrication of nano- and microstructured CMP films for practical applications is currently limited by processing challenges. We report ultrasonic spray chemistry (USC) as an effective method for synthesizing CMP films. The combined effect of ultrasonic cavitation and nebulization in USC provides enough energy to initiate chemical reactions. Thus, USC simultaneously achieves oxidative C–C coupling polymerization and fabrication of thin films. The reaction yield, porosity, and capacitance of the prepared CMP films were strongly dependent on the applied ultrasonic frequency (120 and 180 kHz). Furthermore, USC was used to prepare highly conductive, 3D porous electrodes by a layer-by-layer sequential deposition of CMP and single-walled carbon nanotubes. These supercapacitors demonstrated high specific capacitances (755.7 F/g and 61.3 mF/cm2 at 10 mV/s) with high cycling stability of 95% retention after 20,000 cycles.

Microstructural, mechanical, and wear properties characterization and strengthening mechanisms of Al7075/SiCnp composites processed through ultrasonic cavitation assisted stir-casting

Abstract In this investigation, Al7075 matrix composites reinforced with nano-SiC particles were manufactured using an ultrasonic cavitation assisted stir casting approach. The microstructural characterization by SEM confirms the presence of nano-SiC particles with all the composites, particle size, and with reasonably homogeneous particle dispersion. Characterization by EDS and XRD confirm no trace of oxide formations, and secondary phase or impurities formations with the composites. Optical microscopic examinations shown matrix phase grain refinement due to the presence of nano-SiC particles as-well-as the aggressive ultrasonic cavitation effect. The mechanical properties of the composites have been substantially improved with an increased amount of nano-SiC particles. The manufactured composites demonstrated an outstanding yield strength of 284 MPa with the only 2.0 wt% reinforcement of nano-SiC particles which is 94.52% improvement compared with the yield strength of the ultrasonically treated Al7075 matrix alloy. The strength of Al7075/SiCnp composites has been estimated by various models of strengthening mechanisms. The strengthening contribution due to thermal mismatch is more dominant followed by Orowan strengthening, Hall-Petch mechanism, and load transferring effect for Al7075/SiCnp composites. The strengthening contributions of CTE difference, dislocations interactions between matrix-reinforcement particles, grain-refinement, and load transfer mechanism increased monotonically for the increased percentage of SiCnp content with the composite. The wear resistance of the composites was found as superior to the matrix alloy and was continuously decreased rapidly up to 750 m of sliding distance while it was protracted up to 2250 m. The composite with 2.0% nano-SiC particles reinforcement has shown approximately 79.8% improvement in wear resistance compared with the matrix alloy.

Physical and chemical effects of ultrasonic cavitation on the grain of meat when lamb salting

The data of a study of the influence of ultrasonic lamb salting on the grain of meat raw materials are presented. It has been established, that at ultrasonic salting with a frequency of 35 kHz, structural damage and turgescence of muscle fibers, as well as local destruction of the sarcolemma with the pronounced rugosity are observed, besides the cross-striation is poorly expressed, and the tissue structure is disturbed. An ultrasonic lamb salting with a frequency of 26 kHz is attended by an increase in quantity of crevices and transverse microcracks, loosening up of muscle fibers, formation of cavities between them while maintaining muscle tissue structure, which facilitates the penetration of brine between and inside the muscle fibers. It allows us to recommend ultrasonic treatment at a frequency of 26 kHz for activation of the brine to intensify the technological process wet of lamb salting.

INFLUENCE OF NON-DRUG THERAPY ON REHABILITATION TIME AND SKEET SHOOTING AFTER RHINOSURGICAL INTERVENTIONS

Aim. The paper aims to study the effect of low-frequency ultrasonic cavitation on tissue regeneration and return to skeet shooting in athletes after rhinosurgical interventions. Materials and methods. 16 skeet shooters with eustachitis provoked by nasal septum deviation were treated in the department of otorhinolaryngology at Chelyabinsk city clinical hospital No 1 in the period from 2019 to 2020. Comprehensive postoperative treatment was combined with low-frequency ultrasonic cavitation therapy. Treatment was provided on a daily basis in accordance with clinical recommendations. Objective and subjective clinical and rhinological data about nasal mucous membranes were studied, as well as the effect of low-frequency ultrasonic cavitation on regeneration processes and auditory tube function recovery. Results. The use of low-frequency ultrasonic cavitation therapy in early postoperative period improves regeneration of operated cavities, removes tissue swelling, and restores ventilation function of the auditory tube. Conclusions. Short-term application of low-frequency ultrasonic irrigation of nasal cavities allows to improve tissue regeneration, restore tubal function, remove postsurgical alternative inflammation and swelling of nasal cavity mucosa, return to skeet shooting.