Acoustic cavitation in a liquid medium generates several physical and chemical effects. The oscillation and collapse of cavitation bubbles, driven at low ultrasonic frequencies (e.g., 20 kHz), can generate strong shear forces, microjets, microstreaming and shockwaves. Such strong physical forces have been used in cleaning and flux improvement of ultrafiltration processes. These physical effects have also been shown to deactivate pathogens. The efficiency of deactivation of pathogens is not only dependent on ultrasonic experimental parameters, but also on the properties of the pathogens themselves. Bacteria with thick shell wall are found to be resistant to ultrasonic deactivation process. Some evidence does suggest that the chemical effects (radicals) of acoustic cavitation are also effective in deactivating pathogens. Another aspect of cleaning, namely, purification of water contaminated with organic and inorganic pollutants, has also been discussed in detail. Strong oxidising agents produced within acoustic cavitation bubbles could be used to degrade organic pollutants and convert toxic inorganic pollutants to less harmful substances. The effect of ultrasonic frequency and surface activity of solutes on the sonochemical degradation efficiency has also been discussed in this overview.

Abstract:In this study, poly(vinyl alcohol) were cross-linked with boron in varying concentrations and blend fibers were obtained with diameters ranging from 0.3 μ to 4.0 μm with the use of electrospinning process. The resulting product was characterized by SEM, DSC, and FT-IR techniques. There is no beading tendency in either boron doped or undoped fibers. When the amount of boric acid in PVA solutions was increased the conductivity of the polymer decreased. The data indicated the existence of boron oxide in the polymeric structure and the formation of B-O-C bond. SEM micrographs reveal that higher viscosity favors the formation of thicker fibers. Boron addition seems to disturb the easy detachment of the fibers from the tip of the Taylor Cone

Zinc(II) ion is the first in a row of essential rare elements for living beings. It has been recognized to be an activator for more than 120 hydrolytic enzymes. 1 A quantity of ligand [L = N,N′-bis(salicylidene)-1,3-propane] (0.282 g, 0.001 mol) was dissolved in 30 ml hot DMF by warming and was mixed with 30 ml hot MeOH containing either ZnI2 (0.639 g, 0.002 mol). The mixtures were set aside for one week. The resulting yellow crystals were filtered with a Büchner funnel and dried in ambient air. The chemical diagram of the complex is shown in Fig. 1.Structures with double oxygen bridges are of interest because they have unusual magnetic moments due to the superexchange interactions over the O atoms. Fig. 2 The molecular structure of the title compound, showing 50% probability displacement ellipsoids.

No abstract

No abstract

Two different complexes were obtained from (dmpp) and Cd(II) ions with the aid of pseudohalide ions in non-aqueous solvents. The dinuclear complex formed with thiocyanate ions shows, using XRD, to posses two 1.3 bond m bridges [CdL(SCN) 2 ] 2 . The other dinuclear complex was also seen to form with cyanate ions but with the m-bridge in a 1.

No abstract

No abstract