• Corrosion Science and Technology
• /
• v.18 no.4
• /
• pp.129-137
• /
• 2019

CFRP (Carbon Fiber Reinforced Plastics) is composed of carbon fiber and plastic resin, and is approximately 20 - 50% lighter than metallic materials. CFRP has a low density, higher specific stiffness, specific strength, and high corrosion resistance. Because of these excellent properties, which meet various regulation conditions needed in the industrial fields, CFRP has been widely used in many industries including aviation and ship building. However, CFRP reveals water absorption in water immersion or high humidity environments, and water absorption occurs in an epoxy not carbon fiber, and can be facilitated by higher temperature. Since these properties can induce volume expansion inside CFRP and change the internal stress state and degrade the chemical bond between the fiber and the matrix, the mechanical properties including bond strength may be lowered. This study focused on the effects of NaCl concentration (0.01 - 1% NaCl) and solution temperature ($30-75^{\circ}C$) on the galvanic corrosion between CFRP and A516Gr.55 carbon steel. When NaCl concentration increases 10 times, corrosion rate of a specimen was not affected, but that of galvanic coupled carbon steel increased by 46.9% average. However, when solution temperature increases $10^{\circ}C$, average corrosion rate increased approximately 22%, regardless of single or galvanic coupled specimen.

• Textile Coloration and Finishing
• /
• v.3 no.2
• /
• pp.34-42
• /
• 1991

The effects of electrolyte on dyeing properties of cotton fiber with Congo Red have been studied at 90, 70 and $40^{\circ}C$. Each dyeing carried into an infinite bath with $1\times10^{-4}$ mol/l of Congo Red and with various concentration of electrolytes. The results obtained from this study were as follow; 1. The equilibrium adsorption of dye $(C_\infty)$ values decreased with increasing dyeing temperature, $C_\infty$ values increased in the order KCl>NaCl>LiCl. 2. The values of apparent diffusion coefficients $(D_a)$ increased with increasing dyeing temperature, but $D_a$ values decreased in the order KCl$D_a$ values decreased with increasing electrolyte concentration. 4. Effect of electrolytes decreased with increasing dyeing temperature. 5. The values of standard affinities of dyeing $(-\triangle\mu^{\circ})$, the standard heats of dyeing $(-\triangleH^{\circ})$, and the standard entropies $(-\triangleS^{\circ})$, increased in the order KCl>NaCl>LiCl. 6. Equilibrium adsorption isotherm curve were Freundlich type, and in the Equation y=a.x$^{n}$ , the values of a and n increased in the order KCl>NaCl>LiCl. 7. The value of $-\triangle\mu^{\circ}$, $-\triangleH^{\circ}$, and $-\triangleS^{\circ}$, decreased with increasing electrolyte concentration.

• Korean Journal of Food Science and Technology
• /
• v.34 no.2
• /
• pp.283-289
• /
• 2002

This study was performed to search for potential microorganism that has rapid fermenting and physiological function from anchovy sauce. We isolated three bacterial strains, JM-1, JM-2, and JM-3 with proteolytic and fibrinolytic activity from anchovy sauce. Among the 3 bacterial strains, JM-3 showed the strongest proteolytic and fibrinolytic activity. Bacterial strain JM-3 was gram-positive rod, motile and formed endospore. The 16S rRNA of bacterial strain JM-3 was amplified by PCR and then its sequence was determined by ABI 310 genetic analyzer. The 16S rRNA sequence of bacterial strain JM-3 was compared to BLAST DNA database and identified to Bacillus subtilis with 99% of homology. The optimum temperature, pH and NaCl concentration for growth of B. subtilis JM-3 were $40^{\circ}C$, 5.0 and 0%, respectively. The optimum temperature, pH and NaCl concentration for proteolytic and fibrinolytic enzyme production of B. subtilis JM-3 were same as optimum conditions for growth. At 20% of NaCl concentration which is common NaCl concentration of fish sauce, B. subtilis JM-3 showed about 60% of proteolytic and fibrinolytic activity of 0% NaCl concentration. From above results, we found that B. subtilis JM-3 will be able to used for starter of functional fish sauce.

• Journal of Environmental Science International
• /
• v.25 no.7
• /
• pp.905-916
• /
• 2016

The characteristics of phenol removal and $UV_{254}$ matters variance were investigated and compared by the variation of operating factors (NaCl concentration, air flow rate, initial phenol concentration) in electrochemical reaction (ER) and dielectric barrier discharge plasma reaction (DBDPR), respectively. The phenol removal rate was shown as $1^{st}$ order both in ER and DBDPR. Also, the absorbance of $UV_{254}$ matters which means aromatic intermediates was analyzed to investigate the complete phenol degradation process. In ER, the phenol degradation and aromatic intermediates production rates increased by the increase of NaCl concentration. However, in DBDPR, the variation of NaCl concentration had no effect on the degradation of phenol and $UV_{254}$ matters. Air flow rate had a little effect on the removal of phenol and the variation of $UV_{254}$ matters in ER. The phenol removal rate in ER was a little higher than that in DBDPR. The produced $H_2O_2$ and $O_3$ amounts in ER were 2 times and 10 times higher than those in DBDPR. The chlorine intermediates ($ClO_2$ and free chlorine) were produced in ER, however, they were not produced in DBDPR.

• Journal of the Korean Chemical Society
• /
• v.43 no.1
• /
• pp.36-41
• /
• 1999

The adsorptive stripping voltammetric determination method of trace germanium (IV) using mercaptoacetic acid as a ligand was studied. Optimal conditions were found to be 0.25 M NaCl solution (pH 6.0) containing mercaptoacetic acid concentration of $5.0{\times}10^{-6}M$. The peak potential appeared at - 1.402 V vs. Ag/AgCl. Effects of sodium chloride concentration, mercaptoacetic acid concentration, and accumulation time for the complex of Ge(IV)-Mercaptoacetic acid on the peak current were studied. Amberlite IRC-718 chelating resin was applied to the separation of Ge(IV) from other metal ions.

• Preventive Nutrition and Food Science
• /
• v.2 no.1
• /
• pp.1-5
• /
• 1997

Solution Properties of polyelectrolytic biopolymers such as chitosen, pectin, alginate and etc. are significantly influenced by molecular weight and salt concentrations. The effect of NaCI concentration on the hydrodynamic properties of chitosan in dilute region was investigated for chitosans of varying molecular weight. Intrinsic vicosity([η]) of citosans with 5 different molecular weight was determined by glass capillary viscometer, and the viscosity average molecular weight was calculated using Mark-Houwink equation. Intrinsic viscosity decreased with increasing NaCI concentration for all chitosan samples, and it was proportional to the logarithmic NaCI concentration, i.e.,[η]∝log{TEX}$(C_{NaCl})^{$\alpha$}${/TEX}. Decreasing trend of[η] with NaCI concentration became more pronounced with increasing molecular weight. It was also found that the a values, indicating {TEX}$C_{NaCl}${/TEX} dependence of[η], were linearly correlated with the logarithmic molecular weight({TEX}$R^{2}${/TEX}=0.980). The chain stiffness parameters(B) were calculated by B=S./{TEX}$([η]_{0.1})^{1.32}${/TEX}, in which S was obtained from slope of [η] va {TEX}$I^{-1/2}${/TEX}. The B values of chitosan samples were determined to be 0.113~0071 with a average of 0.09.

• Journal of Environmental Science International
• /
• v.26 no.5
• /
• pp.563-572
• /
• 2017

The Electrocoagulation-Flotation (ECF) process has great potential in wastewater treatment. ECF technology is effective in the removal of colloidal particles, oil-water emulsion, organic pollutants such as microalgae, and heavy metals. Numerous studies have been conducted on ECF; however, many of them used a conventional plate-type aluminum anode. In this study, we determined the effect of changing operational parameters such as power supply time, applied current, NaCl concentration, and pH on the turbidity removal efficiency of kaoline. We also determined the effects of different electrolyte types (NaCl, $MgSO_4$, $CaCl_2$, $Na_2SO_4$, and tap water), as well as the differences caused by using a plate-type and mesh-type aluminum anode, on the turbidity removal efficiency. The results showed that the optimal values of ECF time, applied current, NaCl concentration, and pH were 5 min, 0.35 A, 0.4 g/L NaCl in distilled water, and pH 7, respectively. The results also revealed that the turbidity removal efficiency of kaoline in different electrolytes decreased in the following sequence, given the same conductivity: tap water > $CaCl_2$ > $MgSO_4$ > NaCl > $Na_2SO_4$. The turbidity removal efficiency of the mesh-type aluminum anode was significantly greater than the plate-type aluminum anode.

• Journal of Embryo Transfer
• /
• v.15 no.2
• /
• pp.191-196
• /
• 2000

the present study was carried out to develop a completely defined culture system and determine if high NaCl concentrations in defined (PVA added) or semi-defined (BSA added) medium is toxic to bovine embryos. Oocytes from slaughterhouse ovaries were matured and fertilized in vitro. After 30 h of insemination, only 2-cell stage embryos were selected and cultured for this experiment. The culture media used were as follows : TLP(114 mM of NaCl) + BSA (3 mg/ml), TLP + PVA (1 mg/ml), mTLP(96 mM of NaCl) + BSA, mTLP + PVA. Six to ten embryos were placed into a 30$\mu$1 drop of each medium and the embryos were examined at 10 day post-insemination without medium renewal. The experiment was replicated 4 times. All data were analyzed by chi-square. There were no significant differences among TLP-BSA, mTLP-BSA and mTLP-PVA in blastocyst development (21.6, 17.2 and 20.2%), respectively. Also, no differences were obtained in hatching rates (11.7, 9.9 and 12.2%), respecitively. However, there were significant differences between TLP-PVA (1.7% and 0.6%) and other group in blastocyst formation and hatching rates, respectively (p<0.01). Development of in vitro produced embryos cultured in BSA containing medium was not affected by high NaCl concentration, but in the completely defined medium, embryonic development was highly affected by NaCl. This study shows that reduced NaCl concentration in completely defined medium is beneficial for development of bovine pre-implantation embryos in vitro.

• The Korean Journal of Pesticide Science
• /
• v.12 no.4
• /
• pp.368-374
• /
• 2008

Dry formulation is a limiting step for successful development of microbial bio-pesticides with the antagonistic Gram-negative bacteria because their survival rates are too low during drying and storage. The high concentration of sodium chloride (NaCl) in culture medium that induces osmolyte in bacterial cells is known to increase of survival rate during drying in many Gram-negative bacteria. Effect of NaCl on survival of antagonistic non-pathogenic Erwinia carotovora subsp. carotovora 9-3 (Ecc 9-3) during drying and storage was studied. Growth rate of Ecc 9-3 was not much different up to 0.5 M NaCl in NB while it was lower significantly with 0.7 M NaCl. Survival rates were twice and 3 times higher with 0.5 M NaCl than with no additional NaCl during drying at room temperature and freeze-drying, respectively. Survival rate was also higher with high NaCl in culture medium during storage after drying. It was not much different on storage at $4^{\circ}C$ both of drying at room temperature and freeze-drying. However, the survival rate was higher on storage at $27^{\circ}C$ and $37^{\circ}C$ with high NaCl concentration. Among the additives tested, lactose affects most to survival rate both of drying at room temperature and freeze-drying, and dextrin influenced significantly to survival rate of drying at room temperature.

• Economic and Environmental Geology
• /
• v.46 no.1
• /
• pp.21-28
• /
• 2013

In order to optimize gold leaching from refractory sulfide concentrate, a HCl-NaClO-$FeCl_3$ solution with varying attributes was applied to the roasted concentrate from Uil mine. The gold from Uil mine occurs in the form of invisible gold that is difficult to leach. The results of the gold leaching experiments showed that the best gold leaching parameters were $550^{\circ}C$ of roasting temperature, 2.0 M of concentration, 1.0% of pulp density, and $70^{\circ}C$ of leaching temperature. It is confirmed that the HCl-NaClO-$FeCl_3$ solution was an environmentally friendly method to leach gold and silver from the refractory sulfide concentrate as an alternative lixiviant to cyanide.