Improving Fire Resistance of Mahogany (Swietenia macrophylla) Wood Impregnated with Mixture of Borax and Boric Acid

The study was aimed to investigate the effects of mixture of borax and boric acid concentration and different level of pressure on absorption, retention quantity, and fire resistance properties of mahogany (Swietenia macrophylla). A total of 50 samples of 9 x 19 x 1016 mm (ASTM E 69-02) were taken from mahoganylumber and then air-dried. A total of 45 samples were impregnated with aqueous solutions of borax and boric acid in three different concentrations (5, 7, and 9 %) and at three different pressure levels (5, 7.5, and 10 atm) for 2 hours pressure time, while5 samples were liftedas control. Dried impregnated samples and untreated samples were feeding in flame with lid combustion method refers to ASTM E 69-02. Interestingly, the results showed that borax and boric acid effectively improved the fire resistanceproperties(mass losses, ignition temperature, maximum temperature, and smoke and smolder production)of mahogany wood.Mixtures of borax and boric acid at a concentration level of 9% and pressure of 10 atm arerecommended to obtain the best results compare to the other interactions on combustion properties.

Simulation of pressurized water reactor to find the best control solution

Since it is impossible to simultaneously control all technological and thermal parameters of the nuclear reactor, a vertically distributed model of a power unit was developed, which allows determining the axial offset and analyzing the behavior of thermal and neutron-physical processes of individual zones in core during boron control and movement of rods, as well as regulating the power of the nuclear reactor. For ten vertically distributed zones, neutrons and thermal processes in the reactor core were analyzed, as was the change of the axial offset during the discharge of the reactor load under the influence of the movement of the rods and the increase in the boric acid concentration. The purpose of this publication is to develop a vertically distributed model of the facility and use information technology to find the best solution for the control of a pressurized water reactor.

Analysis of Accumulation and Crystallization of Boric Acid in the Reactor Core during WWER Emergency Operation

The results of hand calculation of boric acid accumulation in the core in a new generation WWER-TOI reactor in case of LOCA are presented. Variants of reducing the H3BO3 concentration in the HA-3 system down to 1, 2, 4 and 8 g/kg are considered. The mass of boric acid deposits on the core internals depending on the value of boric acid concentration in the HA-3 system is determined. The obtained results allow concluding that the accumulation and crystallization of boric acid in the core is possible.

Slow Release of Urea Encapsulated by Starch PVA Matrix

The hydrophobicity of starch/PVA blend was improved by crosslinking with boric acid. It was found that the swelling ratio of the boric acid modified starch/PVA matrix decreased as function of boric acid concentration. FTIR spectra and SEM images demonstrated that the urea had been encapsulated in polymer matrix successfully. The urea release characteristic was explained with respect to the swelling ratio and crosslinking density of polymer matrix. In addition, the matrix displayed a good barrier for controlling the release rate of urea from pellet.

OPTIMIZATION OF BATCH CONDITIONS FOR THE REMOVAL OF BORON BY AMBERLITE IR743

This study is aimed at optimizing the treatment parameters in boron adsorption using a commercial resin, Amberlite IRA 743, via response surface methodology (RSM). The effect of adsorbent dosage, pH and initial boric acid concentration were optimized using RSM in order to obtain high removal efficiencies at low adsorbent dosage and pH levels and high concentrations. The central composite design (CCD) was used to generate the experimental design. The experiments were conducted in a batch process according to the experimental design obtained. The analysis of variance (ANOVA) was performed to obtain a statistical validation of regression models and to study the interaction between treatment parameters. The optimum conditions recommended by the developed model for 100% removal efficiency , was at adsorbent dosage, pH and initial boron concentration of 51g/L, pH 7 and 40mg/L.