• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.323-328
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• 2002

Rapid set accelerators are widely used in tunnel construction, however quality criteria of and dosage are not well established. The density and solid content of admixtures, setting time and compressive strength of paste and mortar with admixtures were investigated to establish the quality criteria. While the early strength of mortar with sodium-silicate, sodium-aluminate and calcium aluminate type admixtures that have high alkali content are very high, but long-term strength are low. Aggregates of shotcrete has to be carefully selected. Sodium-silicate type admixture need longer setting time than the others.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.29 no.4
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• pp.18-27
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• 1997

This study was performed to obtained the optimal delignified condition of exploded wood on the acid hydrolysis with sulfuric acid. Wood chips of pine wood(Pinus desiflora), oak wood(Quercus serrata) and birch wood (Betula platyphylla var. japonica) were treated with a high pressure steam (20-30kgf/$\textrm{cm}^2$, 2-6 minutes). The exploded wood was delignified with sodium hydroxide and sodium chlorite, and then hydrolyzed with sulfuric acid. The result can be summerized as follows ; In the exploded wood treated with sodium hydroxide, the optimal concentration of sodium hydroxide was 1% as content of lignin in the exploded wood. Lignin content of exploded wood treated with sodium chlorite was lower then that sodium hydroxide. The maximum reducing sugar yield of exploded wood treated with 1% sodium hydroxide was lower than non-treated exploded wood. In the case of sodium chlorite treated, the maximum reducing sugar yield was hgher than non-treated exploded wood. Sugar composition of acid hydrolysis solution was composed of xylose and glucose residue, and the rate of glucose residue was increased in high pressure condition.

• Journal of the Korean Home Economics Association
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• v.23 no.1
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• pp.25-31
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• 1985

This study designed not only to elucidate free amino acid, fatty acid composition and mineral content in dried alaska pollack but also to examine calcium, magnesium, poassium and sodium contents in its cooking broth according to each boiling time such as 2.5, 5, 10, 20, and 30 minutes. RESULTS : 1. Glutamic acid in dried alaska pollack was the most abundant free amino acid and was followed in order of aspartic acid, lysin, leucine and histidine. They composed of 50.95% of the total amino acid contents. 2. In dried alaska pollack the most abundant fatty acid was palmitic acid. Essential fatty acid content was 26.57% of the total fatty acid. 3. The calcium, magnesium, potassium and sodium contents in dried alaska pollack showed 10.721 mg%, 9.235mg%, 4072.5mg% and 2299.8% respectively. The amount of magnesium and potassium in cooking broth arrived at the highest level when 20 minute boiling was undertaken and the quantities of magnesium and sodium were the highest when 30 minute boiling was made.

• Structural Engineering and Mechanics
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• v.84 no.4
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• pp.465-477
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• 2022

The formation of biopolymer-soil matrices mainly depends on biopolymer type and concentration, soil type, pore fluid and phase transfer to influence its strengthening efficiency. In this study, the physical and mechanical properties of sodium alginate (SA) treated kaolinite are investigated through compaction test, thread rolling teat, fall cone test and unconfined compression test with considering biopolymer concentration, curing time, initial water content, mixing method. The results show that the liquid limit slightly decreases from 69.9% to 68.3% at 0.2% SA and then gradually increases to 98.3% at 5% SA. At hydrated condition, the unconfined compressive strength (UCS) of SA treated clay at 0.5%, 1%, 2% and 3% concentrations is 2.57, 4.5, 7.1 and 5.48 times of untreated clay (15.7 kPa) at the same initial water content. In addition, the optimum biopolymer concentration, curing time, mixing method and initial water content can be regarded as 2%, 28 days, room temperature water-dry mixing (RD), 50%-55% to achieve the maximum unconfined compressive strength, which corresponds to the UCS increment of 593%, compared to the maximum UCS of untreated clay (780 kPa).

• Journal of the East Asian Society of Dietary Life
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• v.22 no.6
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• pp.734-743
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• 2012

High sodium consumption is a significant nutrition problem in South Korea; however, few studies have examined the awareness and practice of dietitians with respect to low sodium diet in schools. In this study, we collected data from 211 dietitians in 2012. Most respondents indicated that sodium reduction was important in school meals (very important 40.5%, somewhat important 55.6%); however, they rarely checked the sodium content in the nutrition labels of processed foods (never/rarely 74.2%, sometimes 18.7%, always/often 7.2%). The main reason for not checking the sodium content was 'no nutrition table on some processed foods' (38.5%). The most important barrier to sodium reduction in school meals was overcoming the negative taste of students related to a reduced-sodium diet (70.4%). The most frequently used processed foods were processed meat (e.g. ham, bacon) (48.3%), frozen dumplings and noodles (33.8%), and sausage and dressing (14.5%) in school meals. The proportion of dietitians who used processed food ${\geq}$ 2 times per week for the school menu was 72.2% in high school, 28.4% in middle school and 12.4% in elementary school (p<0.05). Upon ranking of the importance of nutrients in school menus, calories received the highest score (4.35 points), followed by macronutrient ratios (4.30), calcium (4.06), iron (3.44) and sodium (3.20). Although most dietitians recognized that sodium reduction was important in school menu planning, they had poor dietary practices. It is suggested that we educate dietitians as well as students about the importance and practice of a reduced sodium diet. Furthermore, it is critical to develop diverse low sodium recipes and have a required nutrition labeling system for all processed foods. Overall, the results of this study could serve as a guide to planning effective nutrition programs to reduce sodium consumption in school feeding programs.

• Journal of Nutrition and Health
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• v.16 no.3
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• pp.162-184
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• 1983

The sodium amuounts of 35 food items and of the city supplied tap water in Seoul area were analyzed ay the Atomic Absorption Spectrophotometry. The Korean food exchange lists for the sodium resricted diets were developed from the available data and the ones newly obtained in this research. The food exchange lists provided in this research is compiled from (1) Milk group (2) Vegetable groups : A with the carbhydrate content of 0-4.9% and -B with that of 5.0-14.9% (3) Fruit group (4 ) Grains and starch food group (5) Meat groups : -Low fat meat and protein foods with the fat content of 0-3.0gm ; -Medium fat meat and protein foods with that of 5.0gm and : -High fat meat and protein foods with that of 8.0gm and (6) Fat group. Lists of sweets, alcoholic and nonalcoholic beverages and seasonings and condiments were also provided with the amount of sodium they contain in portions commonly used. The research described in this report was supported by the Grant from the Department of Education.

• Journal of the Korean Ceramic Society
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• v.50 no.5
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• pp.341-347
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• 2013

Kaolin-based membranes with a pore size of 0.30-0.40 ${\mu}m$ were successfully prepared by a simple pressing route using low-cost starting materials, kaolin and sodium borate. The prepared green bodies were sintered at different temperatures ranging between 900 and $1200^{\circ}C$. The sintered membranes were characterized by X-ray diffraction, mercury porosimetry, scanning electron microscopy, and capillary flowmetry. It was observed that the porosity decreased with an increase in both the sintering temperature and the sodium borate content, whereas the flexural strength increased with an increase in both the sintering temperature and the sodium borate content. The air flow rate decreased with an increase in the sodium borate content. The typical porosity, flexural strength, and specific flow rate of the kaolin-based membrane sintered with 5 wt% sodium borate at $1100^{\circ}C$ were 37%, 19 MPa, and $1{\times}10^{-3}L/min/cm^2$, respectively, at a p of 30 psi.

• Journal of Korean society of Dental Hygiene
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• v.19 no.6
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• pp.1077-1087
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• 2019

Objectives: The purpose of this study was to analyze the risk of dental caries and erosion associated with beverage consumption by measuring the sugar content and acidity of beverages for children, marketed in general food stores and cooperative living associations in Korea. Methods: Sixty types of children's beverages marketed in Korea were selected for the study. Calories, sodium, and carbohydrates in the nutrients per 100 ml, the sugar content, and pH of each beverage were measured. Frequency analysis, independent t-test, and one-way ANOVA were performed (p<0.05). Results: There was no significant difference in sugar content, calories, sodium, and carbohydrate content of regular and cooperative beverages, but the pH of cooperative beverages was significantly higher. Moreover, the mixed drinks had significantly lower sugar content, calories, and carbohydrates than fruit and juice, but the sodium content was significantly higher. Conclusions: When choosing beverages for children, caregivers should be able to easily access information about their impact on the child's oral health. Efforts should be made to maintain appropriate levels of sugar and acidity in beverages for children.

• Korean Journal of Food Science and Technology
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• v.47 no.2
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• pp.145-148
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• 2015

According to the Korea Food Additives Code, sodium metasilicate is permitted for use as a filtering agent for edible oils and fats. Sodium metasilicate is currently used as a food additives to increase the weight of shark fins. In this study, we developed an analytical method to quantify sodium metasilicate in food. Sodium metasilicate content was estimated by measuring the moisture content, pH and silicon content of shark fins. Silicon content was analyzed using inductively coupled plasma-optical emission spectrometry (ICP-OES) following microwave-assisted digestion with $HNO_3$ (65%) and $H_2O_2$ (30%). Shark fin total silicon content was $7.17{\pm}8.92mg/kg$, while the soluble silicon content was $2.34{\pm}3.80mg/kg$. After soaking raw shark fin in an aqueous solution of sodium metasilicate, fin weight, pH and silicon content were measured. These results would be used as the basic information for shark fins safety management.

• Journal of the Korean Wood Science and Technology
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• v.48 no.4
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• pp.503-512
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• 2020

Using Na₂CO₃ versus NaCl as chemical activator, we compared the quality of activated carbon produced from oil palm fronds as raw material. These activators were selected for comparison because both are readily available and are environmentally friendly. In the manufacturing, we used Indonesian National Standard (SNI 06-3730-1995) parameters. For the quality comparison, we determined activated-carbon yield, moisture, ash, volatiles, and fixed-carbon contents; and adsorption capacity of iodine. The best characteristics, assessed by morphological surface analysis and Fourier transform infrared (FTIR) spectral analysis, were observed in the carbon activated by Na₂CO₃ at an activator concentration of 10% and carbonization temperature of 400 ℃. The results were as follows: activated-carbon yield, 84%; water content, 8.80%; ash content, 2.20%; volatiles content, 14.80%; fixed-carbon content, 68.60%; and adsorption capacity of iodine, 888.51 mg/g. Identification using the FTIR spectrophotometer showed the presence of the functional groups O-H, C=O, C=C, C-C, and C-H in the Na₂CO₃-activated carbon.