Sol–gel process was used for the preparation of Rhodamine 6G (R6G) doped silica xerogels, using tetraethylorthosilicate [TEOS, Si(OC2H5)4] as the precursor for the silica network. Silica alcosol was prepared by hydrolysis and polycondensation of ethanol (EtOH) diluted TEOS in the presence of citric acid (CTA) catalyst. The ethanolic R6G was added to the alcosol to trap R6G molecules inside the ...

-Activity expressions are presented for a six end-member, regular solution, site-mixing model for chlorites. The end members are ideal 14-/~ chlorites for which experimental stability data are lacking. Estimates were made of the standard state 25~ and 1 bar molar 3rd law entropies, volumes, and the Maier-Kelley heat capacity coefficients. Experimental stability data from the literature for 14-A...

The technical feasibility of using calcium oxide (CaO) as a sorbent for CO2 and Fe-Cr as a catalyst for the water-gas shift (WGS) reaction using syngas for the steam gasification of biomass was investigated. The effects of temperature, steam to biomass mass ratio, CaO to biomass molar ratio, and Fe-Cr WGS catalyst on gas composition were studied. Within a temperature range of 250 C to 550 C, ...

INTRODUCTION In this prospective longitudinal study, we compared the prevalence of mandibular second molar eruption difficulties in patients treated with appliances to maintain mandibular arch perimeter. Other independent variables (age, molar angulation, space-width ratio, treatment time, and sex) were tested for their value as predictors of eruption difficulty. METHODS Three hundred one pat...

Aureobasidium pullulans ATCC 42023 was cultured under aerobic conditions with glucose, mannose, and glucose analogs as energy sources. The exopolymer extracts produced under these conditions were composed of glucose and mannose. The molar ratio of glucose to mannose in the exopolymer extract and the molecular weight of the exopolymer varied depending on the energy source and culture time. The g...

Background: Mature landfill leachate is a complicated mixture which is resistant to biological treatment processes. The treatment of mature landfill leachate by struvite precipitation and Fenton oxidation was the main objective of the current research. Methods: Struvite with the phosphate/ammonia/magnesium molar ratio of 1/1/1.05 was considered during all experiments. Five initial pHs of 3, 4, ...

Given significant challenges with available measurements of aerosol acidity, proxy methods are frequently used to estimate the acidity of atmospheric particles. In this study, four of the most common aerosol acidity proxies are evaluated and compared: (1) the ion balance method, (2) the molar ratio method, (3) thermodynamic equilibrium models, and (4) the phase partitioning of ammonia. All meth...

The methyl, ethyl, propyl and butyl esters of the fatty acids of Thevetia peruviana seed oil were successfully prepared by the batch-esterification procedures. Various acid catalyst and various molar ratios of fatty acid to alcohol were investigated. H3PO4 was found to be ineffective to catalyze the esterification of the free fatty acid. HCl gas and conc. H2SO4 both proved very effective in cat...