Use Of Ultrasonic Cavitation Research Articles

Low-temperature and Low-pressure HydroThermal Liquefaction (L-HTL) of biomass using ultrasonic cavitation to achieve a local supercritical state in water

HydroThermal Liquefaction (HTL) is a process that involves the reaction of polymer compounds such as cellulose, lignin, synthetic plastics, etc. with near-critical or supercritical water to form low molecular weight liquid compounds, similar to natural oil which is believed to have formed over millions of years. Compared to other biomass recovery methods such as pyrolysis or anaerobic digestion, HTL is highly efficient with an energy efficiency of up to 90%, while the others have an efficiency of only around 30%. However, traditional HTL requires extremely high temperatures (250–450 °C) and pressures (100–350 bar), which are challenging to achieve using large-scale industrial equipment. This study proposes the use of ultrasonic cavitation to induce a supercritical state in water locally, rather than throughout the entire reactor, making it possible to perform HTL reactions using inexpensive and simple devices. The study demonstrates the successful conversion of pure cellulose to low molecular weight liquid compounds using potassium hydroxide as a catalyst.

The Use of Low-Frequency Ultrasonic Cavitation as an Alternative Method for the Treatment of Cervico-Vaginal Antibiotic-Resistant Mixed Infections

In the practice of a modern gynecologist, the problem of cervico-vaginal infections remains one of the most urgent. A causal relationship between the inflammatory process of the mucous membranes of the vagina and cervix and a possible unfavorable outcome in theform of a violation of the biocenosis of the vaginal environment has been clinically confirmed. Despite modern diagnostic technologies and the adopted tactics of two-stage treatment of cervico-vaginal infections, the cases of relapses is high. As a result, the chronic inflammatory process of the lower tract of the urogenital system negatively affects the reproductive health of the woman and the course of the pregnancy onset on the background of immunopathological disorders. Bacterial vaginosis, nonspecific or aerobic vaginitis, candidal vaginitis are often specific pathological processes that manifests on the background of an existing asymptomatic infectious disease. The article discusses topical issues of diagnosis, treatment and prevention of mixed infections of the female reproductive system,and also highlights the topic of antibiotic resistance as a significant obstacle to the effective treatment of patients with infection of the urogenital tract. Possibilities and perspectives of using alternative methods of treating cervico-vaginal infections in outpatient gynecological practice are highlighted. The key points of application and beneficial effects of ultrasound therapy on the body are considered. The purpose of describing a clinical case is to make a decision on the development of a project of a scientific and clinical study witha high degree of evidence, to create a working model for alternative method of physical medicine effectiveness assessment in gynecological practice on the example of the use of low-frequency ultrasonic cavitation with antiseptic solutions followed by the use of a lyophilized culture of lactobacilli. The use of ultrasonic cavitation in clinical practice as an effective alternative method for treating infections of the urogenital tract in women is clearly demonstrated. The clinical effectiveness of the applied method was evaluated, the desired results were obtained in the form of a long-term relapse-free period and restoration of the normal vaginal biocenosis.

Perspectives of Using of Ultrasonic Cavitation in Water Treatment Technology for the Food Productions

Water is one of the main raw materials in the production of most foods; on its composition and quality greatly affect the quality of the finished product. In food production, water is used as a system of potable water supply, and is extracted from underground water sources.At the today’s highly anthropogenic water pressure purification systems in the food industry do not always cope with the difficult task of water treatment, and manufacturers are often faced with the need for additional water treatment.In this connection, the search for new approaches to adjusting the properties and composition of the water is important. The article notes the use of ultrasonic cavitation for water treatment processes for the food industry.

Purification of Liquid Radioactive Waste from Surfactants and Organic Compounds

During the operation of a nuclear power plant, a significant amount of liquid radioactive waste (LRW) is formed and accumulated, its recycling has one of the first priorities. One of the sources of liquid radioactive waste is drain water, which consists of surface-active substances (SA) and organic compounds (OC) of various natures. With this waste composition, the operation of the evaporator is significantly complicated. Thus, recycling of LRW will be simplified after purification from SA and OC. The paper discusses the theoretical aspects of oxidative-cavitation and electrohydrodischarge water purification from organic matter. A schematic circuit of experimental stands of combined cleaning methods was developed and presented. Studies were performed on model solutions of sodium lauryl sulfate (LS) (NaC12H25SO4) and ethylenediaminetetraacetic acid (EDTA) (C10H16N2O8). LS is chosen because it is the most common SA, which is present in the composition of various detergent and decontamination mixtures. The use of EDTA is due to its application in technological processes at nuclear power plants and the presence of liquid radioactive waste in the composition. The destruction of the OS occurs as a result of ozone oxidation, which is constantly splashing through the solution, and amplifies under the action of electrical impulses or ultrasonic (US) cavitation. The work identifies the patterns of reducing concentrations of model solutions, depending on the method of processing, pH-environment and duration of the process. It was found that the destruction of SA and OC occurred better when ozone was combined with US cavitation or electrical discharge, at high pH. The highest performance purification of solutions is as follows: use of electro-discharge and ozone (рН = 6.2) leads to about 71 % collapses, (рН = 10) ~ 61 % OC collapses; use of US cavitation and ozone (рН = 10) ~ 83.3 % SA collapses.

Acoustic cavitation induced generation of stabilizer-free, extremely stable reduced graphene oxide nanodispersion for efficient delivery of paclitaxel in cancer cells

Graphene is one of the highly explored nanomaterials due to its unique and extraordinary properties. In this study, by utilizing a hydrothermal reduction method, graphene oxide (GO) was successfully converted to reduced graphene oxide (RGO) without using any toxic reducing agents. Following this, with the use of ultrasonic cavitation, profoundly stable few layer thick RGO nanodispersion was generated without employing any stabilizers or surfactants. During ultrasonication, shockwaves from the collapse of bubbles cause a higher dispersing energy to the graphene nanosheets which surpass the forces of Van der Waal’s and π-π stacking and thus pave the way to form a stable aqueous nanodispersion of graphene. Ultrasonication systems with different power intensity have been employed to determine the optimum conditions for obtaining the most stable RGO dispersion. The optimised conditions of ultrasonic treatments led to the development of a very stable reduced graphene oxide (RGO) aqueous dispersion. The stability was observed for two years and was analyzed by using Zetasizer by measuring the particle size and zeta potential at regular intervals and found to have exceptional stability. The excellent stability at physiological pH promotes its utilization in nano drug delivery application as a carrier for Paclitaxel (Ptx), an anticancer drug. The in vitro cytotoxicity analysis of Ptx loaded RGO nanodispersion by MTT assay performed on the cell lines revealed the potential of the nanodispersion as a suitable drug carrier. Studies on normal lung cells, MRC-5 and nasopharyngeal cancer cells, HK-1 supported the biocompatibility of RGO-Ptx towards normal cell line. This investigation shows the potential of exceptionally stable RGO-Ptx nanodispersion in nano drug delivery applications.

ИССЛЕДОВАНИЕ ИЗМЕНЕНИЙ МЯСНОГО СЫРЬЯ В ПОСОЛЕ С ИСПОЛЬЗОВАНИЕМ АКУСТИЧЕСКИ АКТИВИРОВАННОГО РАССОЛА

Research on the use of ultrasonic cavitation in the technology of meat products proves high efficiency in regard to the acceleration of technological processes. It is possible to obtain objective data on the forms of integration of moisture with the material applying the method of NMR relaxation using the device “Minispek PC-120” by Bruker Corporation (Germany) in conjunction with other research methods. Cooled low-fat pork, which is subjected to salting with saturated sodium chloride solution (1:3 ratio) after ultrasonic exposure by the frequency of 20 kHz and nameplate rating of 40 % in the production unit such as mercury-vapor console street lamp with piezoceramic radiator, is used as an object of research. Histological studies have shown that when salting meat the microstructural changes in the muscle fibers and connective tissue occur gradually in a certain sequence. Muscle fiber cross banding weakens gradually, the nuclei undergo pycnosis and become homogeneous. Destructive changes in muscle fibers are characterized by the gradual formation of transverse micro cracks and chinked spaces. When exposing the raw meat in the brine containing 3 % of sodium salt, the brine penetrates to a depth of 1.5 cm already on the first day; on the fourth day the brine spreads to the entire muscle depth. Salting brine containing 4% penetrates to a depth of 2.0 cm on the first day of salting, on the fourth day the brine spreads to the entire depth of the muscles. Results of the study of relaxation characteristics of water with the use of NMR method shows that the bulk of the water in the meat is distributed among the factions with the times T12 and T22, and the amount of water with the time T2b is small, and according to the results of many studies, is little subjected to changes. Conducted research has revealed that the use of the activated brine has a positive effect on the kinetics of salting and allows significantly reducing the duration of exposure of whole muscle raw materials in salting by increasing the intensity of the diffusionosmotic processes.

The use of ultrasonic cavitation for near-surface structuring of robust and low-cost AlNi catalysts for hydrogen production

Ultrasonically induced shock waves stimulate intensive interparticle collisions in suspensions and create large local temperature gradients in AlNi particles.

Combined use of ultrasonic cavitation and vacuum therapy in compiex treatments of acute puruient-necrotic processes

A new method for the treatment of patients with acute purulent necrotic processes by means of ultrasonic cavitation and vacuum therapy has been elaborated. The aim was to study the combined influence of ultrasonic cavitation and vacuum therapy on the course of wound healing. The method complements the treatment of patients with severe purulent necrotic processes of soft tissue.

Extremely efficient liquid exfoliation and dispersion of layered materials by unusual acoustic cavitation.

Layered materials must be exfoliated and dispersed in solvents for diverse applications. Usually, highly energetic probe sonication may be considered to be an unfavourable method for the less defective exfoliation and dispersion of layered materials. Here we show that judicious use of ultrasonic cavitation can produce exfoliated transition metal dichalcogenide nanosheets extraordinarily dispersed in non-toxic solvent by minimising the sonolysis of solvent molecules. Our method can also lead to produce less defective, large graphene oxide nanosheets from graphite oxide in a short time (within 10 min), which show high electrical conductivity (>20,000 S m−1) of the printed film. This was achieved by adjusting the ultrasonic probe depth to the liquid surface to generate less energetic cavitation (delivered power ~6 W), while maintaining sufficient acoustic shearing (0.73 m s−1) and generating additional microbubbling by aeration at the liquid surface.

Tensile Properties, Hardness and Micro Structural Analysis of Al 6061 – SiCP Metal Matrix Composites Fabricated by Ultrasonic Cavitation Approach

The combined use of ultrasonic cavitation and mechanical stirring to disperse the silicon carbide particles (SiCp) in molten aluminum alloys has been studied. Composite materials with various weight percentage of Al 6061 alloy (matrix) and SiCp (reinforcement, average particle size 10 micrometers) were fabricated. The microstructure of the composites was investigated by optical microscopy (OM) and scanning electron microscopy (SEM). The micro structural analysis validates the good dispersion of SiCp in the metal matrix. The tension test results reveal that the tensile strength of the as-cast metal matrix composites (MMCs) have been improved significantly for the 5 and 10 weight percentage of SiCp and then decreases. The hardness of MMCs increases and the ductility decreases as the particle percentage increases. The ultrasonic cavitation based fabrication is a novel route for producing wide range of MMCs.

Pressure fields and their effects in membrane cleaning applications

It is known that the use of ultrasonic cavitation can support the cleaning of filtration membranes. We study the final purification step in drinking water production by ultrafiltration through a submerged filter module. The module consists of parallel polymer membrane sheets. Its filtration efficiency is rapidly decreased by fouling. Here, the removal of membrane attached fouling layers by backflushing can successfully be enhanced using ultrasound without membrane damage. To better understand the cleaning mechanism and cavitation properties for further optimization of efficiency, the sound pressure field is measured and the bubble distribution is characterized. Different sound field arrangements are investigated with respect to cleaning performance, while membrane integrity is controlled by turbidity and particle monitoring of the permeate. Results show that a strong influence due to the geometrical configuration can be present, for instance due to impedance effects of the membrane layers.

Removal of thin hard coating on glass substrate by collision of nanometer‐sized particles accelerated in high‐intensity ultrasonic field

The aim of this study is to establish a fundamental recycling technology for optical lenses. In industry, a common conventional technique for cleaning the surface of a small object such as an optical lens is through the use of ultrasonic cavitation. However, the intensity of shock waves caused by the cavitation is difficult to control. The authors have considered that the substances that adhere to lens surfaces, such as hard optical coatings and stains, are removable using collisions, against the lens surface, of many tiny particles that are accelerated by a high‐intensity ultrasonic field. Some physical parameters that dominate the removal effect have been changed systematically to illustrate the surface‐refreshing process for lenses in the experiments. The authors worked to experimentally clarify the particle collision effect on the removal. In addition, the acoustic field was analyzed using finite‐element method. The authors have also attempted to elucidate the principle of the removal technique throug...

Use of Ultrasonic Cavitation in Surface Cleaning: A Mathematical Model to Relate Cleaning Efficiency and Surface Erosion Rate

Ultrasonic cleaning, employing frequencies in the range of 40-200 kHz, is widely used in many industries requiring precision cleanliness in the micrometer to submicron particle size range—e.g., semiconductor wafer fabrication, hard disk drive manufacturing, and integrated circuit assembly. One overriding concern with the use of ultrasonic cleaning for delicate components and assemblies has been the specter of cavitation erosion—surface material loss and other functional degradation due to the impact of shock waves generated by collapsing bubbles and bubble clusters in an oscillating acoustic field. The simultaneous processes of surface cleaning and surface erosion in the presence of a high-frequency ultrasonic field (⩾ 58 kHz) are described here mathematically, and the equations are coupled to allow conceptual optimization of parametric settings to maximize cleaning efficiency while minimizing the level of erosion damage. This theoretical analysis is presented for various ultrasonic field conditions (frequency, intensity, etc.), fluid medium properties (viscosity, density), and surface conditions (hardness, smoothness, etc.). The contribution of acoustic streaming to surface cleaning is incorporated in the model, and is shown to have minimal influence on the optimum cluster collapse pressure, but to have a significant effect on the net cleaning efficiency for the surface.

The use of ultrasonic cavitation peening to improve micro-burr-free surfaces

Advances in machining technology, particularly in the field of micro-machining, have led to the design and creation of miniature components suitable for use in the precision engineering industry. However, the need to contain ubiquitous burrs still exists and has to be addressed. Previous studies on deburring have mostly focused on the parametric investigations of orientation, temperature, type of liquid media and abrasives, frequency, deburring time and power. It is hypothesized that by inducing compressive residual stresses on a pre-machined workpiece surface, the resulting burrs caused by machining can be minimized or even eliminated. The paper presents the findings of an investigative study into the possibility of inducing compressive residual stresses on machined surfaces by the use of ultrasonic cavitation, with the aim of reducing or eliminating burr formation. The paper also briefly reviews the development of ultrasonic cavitation and covers published work on deburring by ultrasonic cavitation. Experimental results are presented on the performance of ultrasonic cavitation peening on the residual stress in Stavax stainless steels and on micro-burr formation.

Acoustic HP field method for the evaluation of properties: shear resistance of lubricants

Studies on the use of ultrasonic cavitation for the disintegration of polymers dissolved in mineral oils applied as V.I. improvers led to the development of an effective system as follows: electro-acoustic unit with and without feedback control, frequency 20kHz, output power 200W, exponential wide tip solid horn, disintegration time 20–120 minutes, sample volume 30–50cm 3. Comparison with various laboratory devices proved this ultrasonic unit to have the highest disintegration efficiency, and a disintegration level identical to that obtained in hydraulic power devices.