SIMULATION OF HOMOGENEOUS NUCLEATION OF BORIC ANHYDRIDE VAPOR IN AXISYMMETRIC NOZZLE

A model of unsteady homogeneous nucleation of boron oxide vapors in chemically reacting mixtures is proposed. The nucleation of condensation nuclei in the model is considered as a bimolecular reaction of boron oxide molecules capture by clusters of boron oxide.

Assessment of Efficiency of Nutrient Uptake of Different Sources of Zn, Mn, Cu and B in Zea mays

Advances in plant nutrition can be achieved by improving the delivery of micronutrients to the plants. The objective of this research was to compare the efficiency of uptake of different sources of zinc, copper and manganese (sulfates, Ethylenediaminetetraacetic acid (EDTA) and oxides) and boron (boric anhydride and colemanite). We conducted all experiments in maize, repeated the experiment twice, using five replicates per treatment, and used two different media. Results showed that for cations, the soluble sources of micronutrients (sulfate and EDTA) in both media were more efficiently taken up. One-way ANOVA with post hoc Tukey for multiple comparisons of means (95% confidence level) was used for all statistical analyses. Sulfate sources were significantly different when compared to the negative control and to the oxide sources. EDTA sources were significantly different when compared to the negative control and to the oxide sources. Oxide sources were not significantly different from the negative control. For boron, we found a similar trend, with boric anhydride being significantly different when compared to the negative control and to colemanite. Colemanite was significantly different when compared to the negative control. This study generated important information about uptake of soluble and insoluble sources of four micronutrients that can be used for the development of new formulations.

New approach to the formation of organo-inorganic borosyloxane polymer structures

Using sol-gel methods, new synthetic approaches to the preparation of boron-containing organic-inorganic hybrid polymers based on boron oxide (boric anhydride), which is a part of many inorganic materials, have been developed. Previously, such methods were used to obtain amorphous silicate glasses and their use allows introducing various inorganic and organic modifiers into the matrix of silicon dioxide and other compounds at temperatures up to 120 °C. Within the framework of this work: a) the conditions for obtaining saturated solutions of boron oxide in organic solvents were found and it was found that boric anhydride is most completely dissolved in triethyl orthoformiate (approximately 25%) at 110-110 °C retaining its structure; b) by the condensation of boric acid with 1,3-dichlorotetraphenyl disiloxane, functional borcyclosiloxanes were synthesized to further modify boron oxide. The reaction conditions, spectral and thermal characteristics of condensation products were investigated. It is shown the increasing in the synthesis time to 15-18 h, a bicyclic borsiloxane is formed; c) homophasic modification of boric anhydride with monofunctional cyclic borsiloxanes was carried out and it was shown that the formation of Si-O-B bonds at 110-120 °C occurs due to the use of anhydrous sol-gel process. Transparent films are obtained from modified boric anhydride solutions deposited on glass and stainless steel, followed by curing at a temperature of 160-280 °C, that are not subjected to hydrolysis under the action of air moisture and are stable in air up to 600 °C. As a result of the work, the possibility of obtaining a borsiloxane type polymeric structures having an inorganic molecular skeleton modified with organosilicon compounds has been investigated.

Determination of Boric Anhydride in Ascharite Ores by Inductively Coupled Plasma Atomic Emission Spectrometry

Inductively coupled plasma atomic emission spectroscopy was applied to the determination of boric anhydride in ascharite ores. Pretreatment method, reagents used for acid decomposition and the interferences from matrix and coexistent elements were discussed in details respectively. The analytical spectral lines were selected while experimental parameters were optimized. The results indicated that after the samples were completely dissolved and collected with hydrochloric acid (1+1) in a sealed container with a reflux condenser by the low-temperature heating method, they could be directly analyzed and determined with ICP-AES at optimized operating parameters. The relative standard deviation of the method is less than 1.4% within the measurement range of 0.1% ~ 40% and the recovery rate is in the range of 98.1% ~ 101.0%. The method was proved satisfactory with wide linear range, low detection limit and also high sensitivity and accuracy.