• Fire Science and Engineering
• /
• v.15 no.2
• /
• pp.6-12
• /
• 2001

The objective of the present work is to examine the cooling effect of a water fire extinguishing agent containing NaBr(30%, w/w). The carbon steel and teflon were used as a hot solid. The temperature on the hot solid surface ranged from $70^{\circ}c$ to $116^{\circ}c$ and water droplet size was 2.6 mm in the experiments. It is suggested that regardless of the hot solid material, the indepth temperature of the case of NaBr solution is lower than that of pure water and the variation of indepth temperature of teflon is higher than that of carbon steel. Regardless of the hot solid material, the time averaged heat flux of the case of pure water is higher than that of NaBr solution. the apparent evaporation time of the case of pure water is shorter than that of NaBr solution.

• Korean Journal of Food Science and Technology
• /
• v.33 no.1
• /
• pp.40-44
• /
• 2001

The effects of TEMPO and NaBr concentration, and temperature on the selective oxidation of primary alcohol groups in corn starch were examined. Reaction time decreased with the increased levels of TEMPO, NaBr and temperature up to 1.7 mM and 100 mM per 100 mM anhydroglucose unit(AGU) and $14^{\circ}C$, respectively, and did not change appreciably at the higher levels. Yield decreased with the increased NaBr levels and was not affected TEMPO level and the temperature. NaBr level and temperature showed negative effects on the selectivity. But the selectivity was not affected by NaBr level and temperature until 100 mM/100 mM AGU and $6^{\circ}C$. TEMPO had no effect on the selectivity significantly.

• Korean Journal of Food Science and Technology
• /
• v.40 no.2
• /
• pp.146-151
• /
• 2008

In this study, batch or semi-continuous reactions, introducing site-specific carboxylic acids in ${\beta}$-1,3-glucan structures, were performed to increase water solubility and gel forming ability, using TEMPO/hypobromite with or without NaBr as catalysts. Regio-selective carboxylic acid formations were determined with infrared (IR) and $^{13}C$ nuclear magnetic resonance (NMR) spectroscopic analyses. The regio-selective reactions with and without NaBr gave oxidation yields of 92.5 and 85.6%, respectively, in the batch type, and yields of 93.9 and 86.4%, respectively, in the semi-continuous type. The reaction times in the batch and semi-continuous reactions without NaBr were delayed by 100 and 150%, respectively, as compared to those with NaBr. A combination of IR and $^{13}C$ NMR analyses were used to confirm the formation of carboxylic acids in ${\beta}$-1,3-glucan. From the batch reactions with and without NaBr, the water solubilities of oxidized products were 50.0 and 55.6%, respectively, and in the semi-continuous reactions they were 52.6 and 53.5%, respectively; while the water solubility of the native ${\beta}$-1,3-glucan was less than 1.0%. Finally, as compared to the native ${\beta}$-1,3-glucan, the gel forming ability of the reaction products was greatly increased irrespective of the presence of NaBr or the reaction type.

• Journal of Magnetics
• /
• v.20 no.4
• /
• pp.342-346
• /
• 2015

The nuclear magnetic resonance of the $^{23}Na$ nucleus in a $NaBrO_3$ single crystal was investigated at the temperature range of 200 K~410 K. The tendencies of temperature dependence of the nuclear quadrupole coupling for the two magnetically inequivalent Na(I) and Na(II) centers are found to be opposite to each other. The nuclear spin-lattice relaxation mechanism of $^{23}Na$ in the $NaBrO_3$ crystal is investigated, and the result revealed that the Raman process is dominant in the temperature range investigated. The relaxation process of the $^{23}Na$ nuclear spins was well described by a single exponential function in time. The $T_1$ values of the $^{23}Na$ nuclei in the $NaBrO_3$ single crystal decreased with increasing temperature. The calculated activation energy for the $^{23}Na$ is $0.032{\pm}0.002eV$.

• Biomedical Science Letters
• /
• v.25 no.4
• /
• pp.348-356
• /
• 2019

This study evaluated the dermal cytotoxicity of sodium bromate (NaBrO₃) and the protective effect of Aster tataricus L. (AT) extract against NaBrO₃-induced cytotoxicity in the cultured NIH3T3 fibroblasts. For this study, it was done the antioxidative effects such as electron donating (ED) activity and lipid peroxidation (LP) activity as well as cell viability. NaBrO₃ significantly decreased cell viability in a dose-dependent manner and its XTT₅₀ value was measured at a concentration of 54.4 μM in these cultures. The cytotoxicity of NaBrO₃ was determined as highly-toxic by Borenfreund and Puerner's toxic criteria. The quercetin, antioxidant significantly increased cell viability against NaBrO₃-induced cytotoxicity. Regarding the protective effect of Aster tataricus (AT) L. extract on NaBrO₃-induced cytotoxicity, AT extract significantly increased the cell viability, the ED ability and the inhibitory ability of LP. From these findings, it suggested that the oxidative stress is involved in the cytotoxicity of NaBrO₃, and AT extract effectively protected NaBrO₃-induced cytotoxicity by antioxidative effects. Conclusively, the natural component like AT extract may be a putative therapeutic agent for the diminution or treatment of the cytotoxicity correlated with oxidative stress like hair dye component, NaBrO₃.

• Corrosion Science and Technology
• /
• v.18 no.3
• /
• pp.110-116
• /
• 2019

Resistances to pitting corrosion of additive manufactured (AM) Ti-6Al-4V alloys in 0.6 M NaBr and 0.6 M NaCl aqueous solutions were compared using micro-droplet cell techniques. With respect to the pitting corrosion resistance, this study focused on two different types of halide anions in aqueous solutions, i.e. $Br^-$ and $Cl^-$. The differences between $Br^-$ and $Cl^-$ halide anions for breakdown on passive films of AM Ti-6Al-4V alloy were explained using Langmuir adsorption model with their equilibrium adsorption coefficients. The results of the analysis showed that the lower resistance to pitting potential of AM Ti-6Al-4V alloy in $Br^-$ aqueous solution was attributed to the higher equilibrium adsorption coefficient of Br-. In addition, micro-electrochemical test results showed that the pitting corrosion resistance of dark grains in additive manufactured Ti-6Al-4V alloy was lower as compared to that of bright grains due to the larger volume of ${\alpha}^{\prime}$ phase that caused the susceptibility to pit initiation.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.17 no.3
• /
• pp.321-328
• /
• 2019

The detection performances of the NaI(Tl), $LaBr_3$(Ce) and $CeBr_3$ scintillation detectors, which can be used to rapidly evaluate the major artificial radionuclides deposited on the soil surface in a nuclear accident or radiological emergency, were compared. Detection performance was assessed by calculating the minimum detectable activity (MDA). The detection efficiency of each detector for artificial radionuclides was semi-empirically determined using mathematical modelling and point-like sources having certified radioactivity. The background gamma-ray energy spectrum for MDA evaluation was obtained from relatively wide and flat grassland, and the MDA values of each detector for the major artificial radionuclides that could be released in nuclear accidents were calculated. As a result, the relative MDA values of each detector regarding surface deposition distribution at normal environmental radiation level were evaluated as high in the order of the NaI(Tl), $LaBr_3$(Ce), and $CeBr_3$ detectors. These results were compared based on each detector's intrinsic and measurement environment background, detection efficiency, and energy resolution for the gamma-ray energy region of the radionuclide of interest.

• Proceedings of the Korean Fiber Society Conference
• /
• 2001.04a
• /
• pp.317-320
• /
• 2001

• Journal of Welding and Joining
• /
• v.25 no.3
• /
• pp.57-63
• /
• 2007

Electrochemical migration characteristics of Pb-free solder alloys are quantitatively correlated with corrosion characteristics in harsh environment conditions. In-situ water drop test and corrosion resistance test for Sn-3.0Ag-0.5Cu solder alloys were carried out in NaBr and NaF solutions to obtain the electrochemical migration lifetime and pitting potential, respectively. Sn-3.0Ag-0.5Cu solder alloy shows similar ionization and electrochemical migration behavior with pure Sn because of Ag and Cu do not migrate due to the formation of resistant intermetallic compounds inside solder itself. Electrochemical migration lifetime in NaBr is longer than in NaF, which seems to be closely related to higher pitting potential in NaBr than NaF solution. Therefore, it was revealed that electrochemical migration lifetime of Sn-3.0Ag-0.5Cu solder alloys showed good correlation to the corrosion resistance, and also the initial ionization step at anode side is believed to be the rate-determining step during electrochemical migration of Pb-free solders in these environments.

• Bulletin of the Korean Chemical Society
• /
• v.16 no.12
• /
• pp.1163-1167
• /
• 1995

The structures of dehydrated Ca4Na4-A (a=12.243(1) Å) and of its bromine sorption complex (a=12.214(1) Å) have been determined by single crystal x-ray diffraction techniques in the cubic space groupPm&bar{3}m at 21(1) ℃. Both crystals were dehydrated at 360 ℃ and 2 X 10-3 Torr for 2 days and one crystal was treated with 180 Torr of bromine vapor at 24 ℃ for 1 h. The structures were refined to final error indices, R1=0.066 and R2=0.078 with 192 reflections and R1=0.109 and R2=0.093 with 100 reflections, respectively, for which I>3σ(I). In these structures, four Ca2+ and four Na+ ions are located on two different threefold axes associated with 6-ring oxygens, respectively. In Ca4Na4-A·6Br2, four Ca2+ ions are recessed 0.28(1) Å into the large cavity and four Na+ ions extend 0.63(1) Å into the sodalite unit. A total of six dibromine molecules are sorbed per unit cell. Each Br2 molecule approaches a framework oxide ion axially with O(1)-Br(1)=3.27(2) Å Br(1)-Br(2)=2.66(6) Å and O(1)-Br(1)-Br(2)=172(1)°, indicating a charge-transfer interaction.