Progress in the Polymer Chemistry of Borates

Abstract

A comparative study has been performed in order to quantify the signal-to-background ratio of Raman measurements in fuel-rich flames using pulsed laser radiation at 532, 489, 355 and 266 nm. For the comparison, spectra were recorded in stable premixed, sooting and non-sooting C 2 H 4 /air flames with equivalence ratios of φ = 1.58, 1.92 and 2.0. The spectra show that the background, consisting mainly of laser-induced emissions from polycyclic aromatic hydrocarbons and from C 2 radicals, changes significantly with the laser wavelength. Although the Raman cross sections increase at shorter wavelength the signal-to-background ratio in the flames investigated is clearly the best for λ = 532 nm and the worst for λ = 266 nm. The presented results show the potential and limitations of concentration measurements by laser Raman scattering in fuel-rich flames and are a valuable aid for the decision of what laser system should be used for measurements in laboratory or practical flames.

Glass formation and vibrational spectra of glasses in the RSO4-Na2B4O7-K2SO4 (R = Mg, Ca, Sr, Ba) systems

“…This location of the glass formation region suggests that the structure of glasses is determined by diborate and triborate structural fragments similar to groupings in the structure of α -Na 2 B 4 O 7 (Fig. 2a) [6].…”

“…According to [6,7], the bands observed in the frequency range 1300-1500 cm -1 in the IR spectra of sodium borate glasses with an alkali metal oxide content up to 36 mol % are assigned predominantly to the B III -O(B IV ) stretching vibrations. The IR spectra of glasses in the systems under investigation (Fig.…”

Recent progress in treatment of dyes wastewater using microbial-electro-Fenton technology

“…dye (bioelectrocatalytic reduction). Direct enzymatic reduction of electrode proved to be more effective, however, 139,140 if cofactors are involved then they should not be 20 Å (2 nm) away from electrode surface. 141,142…”

“…dye (bioelectrocatalytic reduction). Direct enzymatic reduction of electrode proved to be more effective, however, 139,140 if cofactors are involved then they should not be 20 Å (2 nm) away from electrode surface. 141,142 Metals and their alloys have also been reported playing a major role as catalyst due to their different oxidation state in Microbial-electrochemical Fenton system.…”