Influence of ultrasonic treatment on the change of monocrystalline silicon defective region

The article presents the results of an experimental study of ultrasonic action on monocrystalline silicon samples. The influence of the processing modes on the surface strength of the material under study was found.

Obtaining a nanosized silica-humic preparation and its initial approbation

The recent decades have witnessed a significant development and implementation of nanotechnology, including in various branches of agriculture. There is an active search for ways to obtain preparations for plant growing with nanoparticles that can be more rapidly involved in the metabolic processes of plants. This article aims to obtain a nanosized silica-humic preparation and its approbation on potato plants. As a source of humic substances, a liquid humic preparation BoGum (developed by the All-Russian Research Institute of Reclaimed Lands) was used, as a source of silicon – sodium metasilicate. Ultrasonic dispersion method was used for achieving the nanoscale of the samples. A silicon source was introduced in an amount of 0.1% (of SiO2) into BoGum, followed by the application of ultrasonic action for 5, 10, 15 and 20 minutes. The analysis of the obtained samples using a 90 Plus/MAS particle size analyzer has shown that with increasing dispersion time, the effective particle diameter changed insignificantly. At the same time, a redistribution of particles was noted: when the samples were exposed for 20 minutes, the number of smaller particles increased. After 5 minutes of treatment, the range of particle distribution was 115±13–830±23 nm, after 20 minutes of exposure, the particle diameter fell into two regions: 81±8–120±10 and 280±4–470±18 nm. Ultrasonic action contributed to the retention of the stable state of aggregation of the obtained preparation, larger microbiological activity and larger content of humic acid in comparison with the silica-humic preparation, obtained without the application of an ultrasound. The new nanosized silica-humic preparation has been tested on potato plants. Treatment of tubers before planting, followed by foliar spraying of vegetative plants, has contributed to an increase in potato yield by 18.7%. Changes were noted in the content of mono- and polysilicic acids in the soil, as well as the accumulation of silicon in the tops of potatoes when using silicahumic preparations by 0.96% of absolute dry mass on average.

Intensification of the extraction process of phenolic compounds from Acorus calamus leaves

The aim. To determine the intensified method of extraction of phenolic compounds from Acorus calamus leaves and optimal conditions for the process. Materials and methods. In order to develop the optimal intensified method of extraction samples were prepared in different conditions of raw materials-extractant ratio, temperature, time and multiplicity. As a raw materials spectrophotometrically pre-standardized Acorus calamus leaves were used. The extraction was carried out in a hermetically sealed ultrasonic extraction reactor PEX 1 (REUS, Contes, France). As the criteria of extraction efficiency were indicators of dry residue and total amount of flavonoids determined using methods described in State Pharmacopoeia of Ukraine. The amount of flavonoids was determined spectrophotometrically on a certified device Specord 200 (Analytik Jena, Germany). Results. According to our research results it was found that ultrasonic action and addition of surfactant significantly improves the efficiency of the extraction process. The optimal conditions for the process were determined. Experimentally proved that the rational raw material-extractant ratio is 1:15. Comparative study of the extraction process with different temperatures showed that the highest amount of extractives is achieved at temperature 70 °C and 45 min of duration. The optimal extraction multiplicity is 3. Conclusions. As a result of the study, the intensified extraction method for Acorus calamus leaves – re-maceration with ultrasound – was established. The conducted researches allowed to develop the method of extraction, expedient in the conditions of the modern pharmaceutical industry.

Densification of wood – Chemical and structural changes due to ultrasonic and mechanical treatment

This paper presents the state of the art of wood surface densification method by pressing with ultrasound. The properties of ultrasound and its effects on the structure and properties of wood, as well as ultrasound-induced chemical changes in wood material, are described. The following research results were analyzed: the effects of acoustic cavitation in wood material, plasticization of wood lignin by processing with ultrasound, the influence of ultrasound on the wood anatomical structure, the combined effect of ultrasound and wood pressing, and the sterilization of wood using ultrasonic action. Ultrasound causes conversion of lignin from glassy into a quasi-rubbery state, which facilitates compaction of the workpiece surface. Additionally, under ultrasound, growth and collapse of gas bubbles (cavitation phenomena) occur within a liquid medium of wooden substance accompanied by high local temperatures and production of chemically active radicals. This contributes to the destruction of the former and the formation of new bonds in the wood substance, which is important for increasing the stability of the workpiece size after densification. The conclusions made about the ultrasound can be effectively used for the wood plasticization and about prospects of joint use of wood pressing and ultrasound for wood surface densification.

Densification of wood – Chemical and structural changes due to ultrasonic and mechanical treatment

This paper presents the state of the art of wood surface densification method by pressing with ultrasound. The properties of ultrasound and its effects on the structure and properties of wood, as well as ultrasound-induced chemical changes in wood material, are described. The following research results were analyzed: the effects of acoustic cavitation in wood material, plasticization of wood lignin by processing with ultrasound, the influence of ultrasound on the wood anatomical structure, the combined effect of ultrasound and wood pressing, and the sterilization of wood using ultrasonic action. Ultrasound causes conversion of lignin from glassy into a quasi-rubbery state, which facilitates compaction of the workpiece surface. Additionally, under ultrasound, growth and collapse of gas bubbles (cavitation phenomena) occur within a liquid medium of wooden substance accompanied by high local temperatures and production of chemically active radicals. This contributes to the destruction of the former and the formation of new bonds in the wood substance, which is important for increasing the stability of the workpiece size after densification. The conclusions made about the ultrasound can be effectively used for the wood plasticization and about prospects of joint use of wood pressing and ultrasound for wood surface densification.

Ultrasound-assisted dewatering of crude oil from Kumkol oilfield

Reducing the water content of crude oil is a necessary step in preparing oil for transportation and processing. This task is complicated by the presence of stable water-in-oil emulsions. The most widely used approach to oil demulsification is exploring chemical demulsifiers. However, the high cost and impossibility of regenerating the latter require the search for new ways to destroy water-oil emulsions. One of the promising areas is the use of ultrasound. This paper presents the results of studies on the ultrasonic treatment of four samples of emulsions with different water content (8.74; 15; 25 and 30 vol.%) based on oil from the Kumkol oilfield (Kazakhstan). Samples of emulsions were subjected to ultrasonic action at a frequency of 40 kHz for 5-60 min at a temperature of 70±1°C, followed by settling for 40 min at the indicated temperature. The influence of the initial water content in the emulsion, the acoustic intensity, as well as the duration of ultrasonic treatment on the dewatering ratio was investigated. It was found that the residual water content in the oil was 5.04- 7.82 vol.%. Ultrasonic treatment of crude oil from the Kumkol oilfield can be used for preliminary dewatering, to subsequently reduce the consumption of chemical demulsifiers.

Ultrasound in the Processes of Treatment of Oil-Contamined Waste: Overview

An overview of the main methods of cleaning oil-contaminated wastewater, intensified by ultrasonic action, is given. The advantages and disadvantages of the methods, as well as the advantages of methods when using ultrasound are noted. It is shown that ultrasound does not replace the existing methods of purification of oil-contaminated wastewater, but only selectively supplements them, which is primarily associated with synergistic effects arising in water purification processes.

The Effect of Ultrasonic Treatments on Current Transport Processes in Al-Al2O3-p-CdTe-Mo Structure

It was established that ultrasonic treatments (USTs) have practically no effect on the patterns of current flow in the Al-Al2O3-p-CdTe-Mo structure in the forward direction, namely, as in the absence of ultrasonic action, they appear in the sequence J∼V, J∼V2, J∼V5.3, and J∼V2. The effect of ultrasonic treatments affects only the magnitude of the flowing current; at low voltages, the current becomes somewhat larger, and at high voltages, it practically does not change. Changes in the magnitude of the flowing current are explained on the basis of the assumption that the recombination of nonequilibrium carriers in such a structure occurs through complex pair recombination complexes and, as a result of ultrasonic treatments, the number of both small acceptors and deep recombination centers increases.