Showing papers in "Ultrasonics Sonochemistry in 2001"

TL;DR: This paper presents a review of the ultrasonically assisted extraction of bioactive principles from herbs under European community grants under the COPERNICUS programme and in a COST D10 network.

TL;DR: A series of experiments has been developed to investigate the effect of ultrasonic energy on the vegetal material and the solvent used and several results concerning the ultrasonic extractive value, ultrasonic swelling index and the effects of frequency on Vegetal material are presented.

TL;DR: The sonication-assisted extraction of ginseng saponins was found to be about three times faster than the traditional extraction method and not only more efficient but also convenient for the recovery and purification of the active ingredients of plant materials.

TL;DR: Wide prospects of commercial application for the ultrasonic melt treatment of light alloys are shown, including new fields of use such as semisolid processing, low-friction alloys, and natural composites.

TL;DR: The comparative study of the degradation of Rhodamine B using various ultrasonic equipments establishes a relationship between the area-specific parameter (intensity) and the volume- specific parameter (density) of reactivity.

TL;DR: The application of ultrasound to methanolic extraction gave a significant reduction in extraction time and an increase in maximum yield of rutin from Sophora japonica.

TL;DR: The arising problems and basic effects when applying ultrasound during sorption processes in order to show the potentials of this desorption process, and the focus is laid in particular on the influence of ultrasound frequency and intensity.

TL;DR: It was found that ultrasonic waves decrease the supersaturation limits and modify the morphology of the crystals produced, and the average crystal size decreases with an increase of ultrasonic power.

TL;DR: It is essential to consider the adsorption and desorption kinetics to get proper estimates of the degradation rates when the rates of degradation of TCP are calculated by analyzing the residual concentration of the compound in the liquid.

TL;DR: Application of two wave sources, as used in the study, revealed that it is possible to save energy through lowering of time of operation process and show that sinusoidal ultrasound even at larger intensity has some limitations with single frequency.

TL;DR: The ultrasonic irradiation played an important role to progress the heterogeneous reaction and the preparation of very fine HAp powder.

TL;DR: An improved colorimetric determination reveals that Pt(IV) ion is reduced to zero valent metal in two steps: step (1)--Pt( IV) ion to Pt(II) ion, and after the completion of step (2), step (3) sets in, and it appears that rapid scrambling reactions among platinum ions and/or atoms take place.

TL;DR: This study confirms the general assumption that the shear forces generated by the rapid motion of the solvent following cavitational collapse are responsible for the breakage of the chemical bonds within the polymer.

TL;DR: Continuous ultrasound emulsification experiments were carried out to elucidate the effect of hydrostatic pressure and gas content on the result of droplet disruption and no clear effect on the droplet size of the emulsion is observed.

TL;DR: The degradation of 2-chlorophenol in water was kinetically investigated using the following different techniques, employed either separately or simultaneously, always with the same experimental set-up: light irradiation (315-400 nm), sonication, photocatalysis with different types of TiO2, photoc atalysis with sonication.

TL;DR: The study showed that hydrogen peroxide can improve the sonochemical reaction and gases dissolved in reaction matrix can affect the process to a small extent.

TL;DR: Mixing time measurements have been carried out in a cylindrical reactor irradiated with an ultrasonic horn fitted with different size tips and a correlation has been developed for the prediction of the mixing time using a method similar to that used for liquid jet mixing.

TL;DR: A new model was developed, incorporating gas phase OHradical induced degradation, next to pyrolysis, that illustrated that at micromolar concentrations the OH radical induced degradation becomes significant.

TL;DR: Through numerical simulation, the modelling of bubble migration allow us to have an insight on the privileged sites of the chemical reactions and determinate emergence sites of mechanically active cavitation bubbles.

TL;DR: Experiments related to the industrial production of medicinal tinctures of sage and valerian were performed using ultrasonically assisted extraction and quality of the final tincture was evaluated by gas chromatography and dry residue determination.

TL;DR: Application of high-intensity ultrasonic irradiation in conjunction with oxidative process using commercial oxidants H2O2 was investigated as an alternative to remove humic substances from the raw water prior to chlorination by the conventional coagulation and filtration method using aluminium sulphate.

TL;DR: P powdered TiO(2) photocatalyst suspended in distilled water should be simultaneously irradiated by light and ultrasound to decompose water and this sonophotocatalytic reaction was effective on the decomposition of water.

TL;DR: Kinetics of the acid-catalyzed hydrolysis of ethyl acetate in ethanol-water binary solutions were investigated without sonication and under ultrasound at 22 kHz to suggest that ultrasonic acceleration of the reaction may be interrelated to the perturbation of the molecular structure of the binary solvent.

TL;DR: Results indicate that oxygen was an important precursor in the degradation of the PAHs and decreased PAH degradation rate constants by scavenging oxygen derived reactive transients.

TL;DR: It is demonstrated that the emission from alkali metals arose from the gas phase of bubbles and excitation/de-excitation mechanisms are chemiluminescent in essence.

TL;DR: There is an optimum frequency in the range from 92 to 518 kHz for effective polymerization, and observations indicate that polymerization under sonication is influenced by the irradiated frequency.

TL;DR: The experimental data reveal that collision and coalescence of bubbles is a predominant phenomenon that limits their individual lifetime.

TL;DR: The goal of this overview is to provide a comprehensive picture about the fields of both enantioselective and diastereoselectives reactions accelerated or initiated by ultrasounds.

TL;DR: Experiments carried out in the presence of 2-methyl-2-nitrosopropane resulted in the detection of radicals originating from thermal decomposition of the spin trap, showing its lability under ultrasonic radiation.

TL;DR: Saponification of three different vegetable oils shows that the almond oil is saponified easier than the two others and this could be related to their properties such as surface tension, viscosity and density.