• Electrical & Electronic Materials
• /
• v.9 no.3
• /
• pp.284-290
• /
• 1996

The electrical properties of bulk galsses in the system Na$_{2}$O-CaO-Al$_{2}$O$_{3}$-B$_{2}$O$_{3}$-SiO$_{2}$ containing 20 to 30mol% sodium which have been subjected to a sodium .tautm. silver ion exchange reaction for 24, 36 and 48 hrs. were analysed by impedance spectroscopy method. Ion exchanged glasses exhibit activation energy values lower than those of the untreated ones. The electrical conductivity increase with sodium content and ion exchanging time. In this experiment the electrical conductivity exhibits a manximum value of 1.78*10$^{-4}$ S/cm at 200.deg. C which contains 30mol% sodium and subjects ion exchange reaction for 48hrs.

• Fashion & Textile Research Journal
• /
• v.10 no.1
• /
• pp.101-105
• /
• 2008

This study was concerned with the influence of reaction conditions on the surface friction properties of Syrene-Butadiene Rubber(SBR) sheet when it was chlorinated by chemical treatment method using the sodium hypochlorite and sulfuric acid. The results of this study were as follows. SEM photographs of chlorinated SBR surface showed uneven etching caused by the chlorination. In the FTIR spectra, the intensity of C=C peak of SBR was decreased with increasing the concentration of sodium hypochlorite. Otherwise there was no trace of C=C peak in spectrum of SBR treated with 5 wt% NaOCl with pH 0.1 for 90 seconds. EDX spectra showed that relative content of chlorine of SBR was increased with increasing the amount of sodium hypochlorite, and also affected with pH condition of acid solution. Friction angle and friction coefficient of SBR were influenced with concentration of sodium hypochlorite, but were not with pH condition of acid solution.

• Journal of the Korean Ceramic Society
• /
• v.31 no.5
• /
• pp.538-542
• /
• 1994

The kinetics and mechanism on the hydration of granulated blastfurnace slag-sodium silicate systems were studied by ignition loss, unreacted slag determination, XRD, DTA and SEM(EDS). From this experiment the following results were obtained. The amount of slag reaction was increased with the content of sodium silicate and also C-S-H, C4AH13, and C2ASH8 were formed to be the main products up to 28 days of hydration. Sodium silicate was not only an activator for slag hydration but also a binder in the hydration. The amount of slag reaction activated by sodium silicate was a nearly same for Ca(OH)2 activated slag, but it was smaller one than that activated by NaOH. However there was no difference in hydration products.

• Journal of Nutrition and Health
• /
• v.10 no.1
• /
• pp.38-43
• /
• 1977

This study was designed to find out the status of low sodium diet in 27 hospitals located in Seoul and rural areas. The study was conducted from the beginning of June, 1976 to October, 1976. The differences in Na, protein and calorie contents between the hospitals in Seoul an ones in rural areas, and between the medical college attached hospitals and general ones, were compared by means of t-test. Correlation coefficient were made among Na, protein and calorie. In order to find out which food group is the major source of Na in the diet, six food groups were divided and Na content in each was calculated. The results showed that average daily Na intake of 27 hospitals was 2,382mg which is regarded as mild restriction. Average daily protein and calorie intakes were 94gm and 2,438 cal respectively. About 60% of hospitals restricted sodium at mild level $(2,300mg{\sim}4,600mg)$ and 33% at moderate $(1,000mg{\sim}2,300mg)$ and only 7% of the subjects were Planning strict sodium restriction $(250mg{\sim}500mg)$ There was statistically significant differences in Na contents between Seoul and rural areas. But no significant difference was found between medical college attached hospitals and general ones. The correlation between the average daily intakes of Na and protein was found not to be significant but protein and calorie intakes were related each other. When the total sodium intakes divided into six groups, about 74% were supplied by condiments (Food group 6th).

• The Korean Journal of Physiology and Pharmacology
• /
• v.1 no.5
• /
• pp.537-546
• /
• 1997

It has been postulated that the intracellular taurine is co-transported with $Na^+$down a concentration gradient and prevents the intracellular accumulation of sodium. It is therefore, expected that an elevated level of intracellular taurine prevents the sodium-promoted calcium influx to protect the cellular damages associated with sodium and calcium overload. In the present study, we evaluated the effects of intra- and extracellular taurine on the myocardial $Na^+$and$Ca^{++}$ contents and the cardiac functions in isolated rat hearts which were loaded with sodium by monensin, a $Na^+-ionophore$. Monensin caused a dose-dependent increase in intracellular $Na^+$ accompanied with a subsequent increase in intracellular $Ca^{++}$ and a mechanical dysfunction. In this monensin-treated heart, myocardial taurine content was decreased with a concomittent increase in the release of taurine. The monensin-induced increases in intracellular $Na^+$, $Ca^{++}$ and depression of cardiac function were prevented in the hearts of which taurine content had been increased by high-taurine diet. Conversely, in the hearts of which taurine concentration gradient had been decreased by addition of taurine in the perfusate, the monensin-induced increases in $Na^+$, $Ca^{++}$ and functional depression were accelerated. These results suggest that taurine, depending on the intra-extracellular concentration gradient, can affect intracellular sodium and calcium concentrations, and that an increased intracellular taurine may play a role in protection of myocardial dysfunction associated with the sodium and calcium overload.

• Food Science of Animal Resources
• /
• v.26 no.1
• /
• pp.15-19
• /
• 2006

The aim of this study was to determine the best processing conditions for producing of dried lean pork as a ready-to-serve product without using large-scale machines. Lean pork sausage was produced using 1.27% sodium chloride, 0.075% sodium polyphosphate, 0.06% sodium ascorbate, 0.075% sodium pyrophosphate, 0.009% sodium nitrite, 0.009% dextrin, 0.11% sodium glutamate and 1.4% spice mixture. The most appropriate slice thickness for drying was examined by slicing the sausage at a 0.5, 1 and 2 cm thickness. The drying temperatures were determined by drying the sausage slices at 35, 48 and $68^{\circ}$. The total drying period was for 12 hr, In order to examine the ability of this process to sterilize the pork, the raw meat materials were inoculated with Escherichia coli (E. coli). The optimal conditions for producing lean pork sausages were a 2 cm slice thickness and drying temperature of $68^{\circ}C$ for 12 hr, The moisture content water activity, color, hardness and pH were measured in the dried product. The product had a moisture content of 47.5% and a water activity of 0.93. There was a 47.7% percentage reduction in moisture. The dried product tested negative for E. coli even though the raw meat materials been inoculated with E. coli.

• Journal of the Korean Wood Science and Technology
• /
• v.49 no.1
• /
• pp.14-22
• /
• 2021

The objective of this study was to investigate the effect of alkali-washing with different sodium hydroxide concentrations on the chemical compositions of steam-treated Betung bamboo strand. Strands were subjected to steam treatment at 126 ℃ for 1 h under 0.14 MPa pressure and followed by washing with 1-5% sodium hydroxide solution for 30 sec. The alteration of structural and non-structural chemical components content of bamboo strands was evaluated. Steam and washing treatments with various concentrations of sodium hydroxide solution considerably reduced the extractive content of bamboo strands, and the cell wall chemical components of the strand in the small degree. FTIR analysis showed noticeable changes in peaks related to hemicellulose and lignin. The relative crystallinity increased significantly after steam and washing treatment with sodium hydroxide up to 3% concentration. SEM Images showed smooth and clean strands surface after washing with 3% sodium hydroxide.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.8 no.1
• /
• pp.37-45
• /
• 1975

The present study was ,conducted to evaluate the effects of condensed phosphates on the refeezing damage of Alaska pollack muscle. The fillets were dipped in such solution as 5 and $10\%$ sodium polyphosphate, 1 and $5\%$ mixture of sodium polyphosphate and sodium pyrophosphate (1:1, w/w) for 1 and 5 minutes, respectively, before refreezing. And fillets were frozen at $27^{\circ}C\~28^{\circ}C$ and stored for 15 days at $-18^{\circ}\~-20^{\circ}$. The degree of denaturation was estimated by determining amounts of drip relased, content of total solids, nitrogen, and DNA in the drip an cooking-weight-loss. Phosphorus absorbed in the muscle was also determined. Phosphorus absorbed in the fillets treated with loft solution of sodium polyphosphate for 5 minutes amounted to 101 mg/100g muscle as $P_2O_5$. The absorption was dependent on tile concentration of treating solution rather than on the dipping time. The increase of phosphorus absorption seemed to affect to reduction of drip. Among the treating conditions, $10\%$, 5 minutes and $10\%$ 1 minute with sodium polyphosphate appeared most effective ones on drip reduction. The effect of $5\%$, minutes with the mixture of sodium polyphosphate and sodium pyrophosphate did not show so benefitable effect in refrozen fillets. As a tendency total solids, nitrogen, and DNA in tile drip varied proportionally to the amount of drip released. And the content of DNA was lower than the amount. Treatment, at higher the concentration and longer the dipping time, resulted in the lower cooking-weight-loss and the better quality on organoleptic test of thawed fillets.

• Food Science of Animal Resources
• /
• v.40 no.6
• /
• pp.946-956
• /
• 2020

To identify the effect of sodium-alternative curing salts on the quality properties of salami through the ripening process, four salami treatments were prepared with different curing salts, T1 (-control, NaCl 1.9%), T2 (+control, NaCl 1.9%+NaNO₂ 0.01%), T3 (KCl 1.9%+NaNO₂ 0.01%), and T4 (MgCl₂ 1.9%+NaNO₂ 0.01%), under 40 days ripening conditions. Sodium-alternative salts (T3 or T4) showed characteristically different quality traits compared with T2. Especially, T3 had lower pH, water activity, volatile basic nitrogen, and lipid oxidation after 20 days of ripening period, compare with T2 or T4 (p<0.05). Sodium nitrite had critical impact on increased a* values, and T3 showed higher a* values compared with T2 or T4 (p<0.05). Sodium nitrite reduced initial growth of coliforms but sodium-alternative salts did not affect microbial growth patterns. T2-T4 containing sodium nitrite had higher content of umami nucleotide flavor compounds compared with T1, regardless of the chlorine salt species. The combined use of sodium-alternative curing salts and minimal sodium nitrite was found to be an applicable strategy on development of low sodium salami without a trade-off of the product quality.

• Nutrition Research and Practice
• /
• v.17 no.4
• /
• pp.812-825
• /
• 2023

BACKGROUND/OBJECTIVES: This study investigated the importance and performance level of sodium reduction practices in school meal service by school nutrition teachers and dietitians, and compared them according to school level and placement of the school nutrition teacher. SUBJECTS/METHODS: An online survey was conducted with 608 nutrition teachers and dietitians in schools in the Republic of Korea from September 28 to November 12, 2021 (response rate: 57%). The questionnaire comprised 11 items related to sodium reduction practices (purchasing, food preparation and serving, and education). The importance and performance level of each item was rated on a 5-point scale. The mean differences were analyzed using t-tests or one-way analyses of variance and Duncan's post-hoc tests. An importance-performance analysis was performed on sodium reduction practices. RESULTS: Participating in sodium reduction education, sodium reduction education for cooks, and sodium reduction education for students were assessed to have high importance but low performance. Overall, the higher the school level, the lower was the importance level of sodium reduction practices. The performance in kindergartens and elementary schools was higher than that in middle and high schools. The importance in the purchasing category perceived by dietitians was lower as compared to nutrition teachers. In addition, the performance in the purchasing, food preparation and serving, and education categories perceived by dietitians was lower than those of nutrition teachers. CONCLUSION: Sodium reduction education for nutrition teachers and dietitians, cooks, and students should prioritize practicing sodium reduction in school meal service. Specific guidelines for managing sodium reduction at all stages-purchasing, food preparation, and serving-should also be developed. The results could be used as basic data to reduce the sodium content in school meals.