• Advances in concrete construction
• /
• v.8 no.1
• /
• pp.21-31
• /
• 2019

The rich recipe of ultra high performance concrete (UHPC) offers the higher mechanical, durability and dense microstructure property. The variable like cement/sand ratio, amount of supplementary cementitious material, water/binder ratio, amount of fiber etc. alters the UHPC hardened properties to any extent. Therefore, to understand the effects of these variables on the performance of UHPC, inevitably a stage-wise development is required. In the present experimental study, the effect of sand/cement ratio, the addition of finer material (fly ash and quartz powder) and, hybrid fiber on the fresh, compressive and microstructural property of UHPC is evaluated. The experiment is conducted in three phases; the first phase evaluates the flow value and strength attainment of ingredients, the second phase evaluates the efficiency of finer materials (fly ash and quartz powder) to develop the UHPC and the third phase evaluate the effect of hybrid fiber on the flow value and strength of ultra high performance hybrid fiber reinforced concrete (UHP-HFRC). It has been seen that the addition of fly ash improves the flow value and compressive strength of UHPC as compared to quartz powder. Further, the usage of hybrid fiber in fly ash contained matrix decreases the flow value and improves the strength of the UHP-HFRC matrix. The dense interface between matrix and fiber and, a higher amount of calcium silicate hydrate (CSH) in fly ash contained UHP-HFRC is revealed by SEM and XRD respectively. The dense interface (bond between the fiber and the UHPC matrix) and the higher CSH formation are the reason for the improvement in the compressive strength of fly ash based UHP-HFRC. The differential thermal analysis (DTA/TGA) shows the similar type of mass loss pattern, however, the amount of mass loss differs in fly ash and quartz powder contained UHP-HFRC.

• Structural Monitoring and Maintenance
• /
• v.2 no.1
• /
• pp.35-48
• /
• 2015

The main objective of this study is to evaluate the long-term performance of various concrete composites in natural marine environment prevailing in the Gulf region. Durability assessment studies of such nature are usually carried out under aggressive environments that constitute seawater, chloride and sulfate laden soils and wind, and groundwater conditions. These studies are very vital for sustainable development of marine and off shore reinforced concrete structures of industrial design such as petroleum installations. First round of testing and evaluation, which is presented in this paper, were performed by standard tests under laboratory conditions. Laboratory results presented in this paper will be corroborated with test outcome of ongoing three years field exposure conditions. The field study will include different parameters of investigation for high performance concrete including corrosion inhibitors, type of reinforcement, natural and industrial pozzolanic additives, water to cement ratio, water type, cover thickness, curing conditions, and concrete coatings. Like the laboratory specimens, samples in the field will be monitored for corrosion induced deterioration signs and for any signs of failureover initial period ofthree years. In this paper, laboratory results pertaining to microsilica (SF), ground granulated blast furnace slag (GGBS), epoxy coated rebars and calcium nitrite corrosion inhibitor are very conclusive. Results affirmed that the supplementary cementing materials such as GGBS and SF significantly impacted and enhanced concrete resistivity to chloride ions penetration and hence decrease the corrosion activities on steel bars protected by such concretes. As for epoxy coated rebars applications under high chloride laden conditions, results showed great concern to integrity of the epoxy coating layer on the bar and its stability. On the other hand corrosion inhibiting admixtures such as calcium nitrite proved to be more effective when used in combination with the pozzolanic additives such as GGBS and microsilica.

• Journal of the Korean Society of Food Culture
• /
• v.22 no.4
• /
• pp.503-510
• /
• 2007

The nutrient intakes of elementary, middle and high school children whether participate the school milk program or not, were assessed by estimating meals provided for one month. The schools were selected at random all around the country, and were 52 and 32 schools which were participating and non-participating in the school milk supplying program, respectively. Overall, the students, were enrolled schools with participating in milk program, intake higher energy, protein (p<0.01), lipid, sugar, Ca(p<0.001), P (p<0.001), Fe, K, Vit A and cholesterol compared to those of students were enrolled schools of non-participating, statistical significantly. The calcium intake of students participating in school milk program (PMP) about 1.5 times higher than those of students in the schools of non-participating milk program (NPMP), especially. The calcium intake of student were $24{\sim}28%$ and $43%{\sim}51%$ of RDA in PNP and NPNP students, respectively. Therefore, the calcium intake quantities of students, were provided with the school lunch without milk, were low-end limit of RDA. Considering the school lunch with the Koreanstyle foods mostly, the milk supplying were solved this problem. Especially, the difference of the nutrients intake which were followed in the case PMP which will consider an average 15-20% food left, magnification of milk supplying program in schools may help more growth of children, so the expansion of milk supplying programs in the schools were demanded, urgently.

• Journal of the Korean Geosynthetics Society
• /
• v.22 no.3
• /
• pp.87-95
• /
• 2023

Recently, redevelopment of the original downtown area is underway, the necessity of construction in adjacent location is increasing. However, excavations in dense urban areas are prone to ground problems due to various causes, so it is necessary to use materials and methods that can minimize such problems. As a general earth retaining method, various methods such as diaphragm wall and CIP method are applied using cement. However, since a large amount of cement is used for the installation of earth retaining method, it is necessary to conduct research on the development of new cement substitute materials to significantly reduce greenhouse gas emissions. In this study, we utilized the hardening reaction of blast furnace slag powder, desulfurized gypsum and high calcium fly ash by alkali activation and applied it to the SCW method. As a result, it was analyzed that the compressive strength of solidified soil using development solidification material was 96.2 ~ 106.3% of OPC at 28 days of curing. In addition, the strength increment ratio was 2.06 for sandy soil and 2.41 for clayey soil, which was higher than 1.85 of OPC. It seems an advantageous in terms of long-term strength. In addition, from the environmental point of view, it was analyzed that there is no elution of heavy metals and that greenhouse gas emissions can be dramatically reduced. Therefore, if further studies are conducted, it can be applied to the SCW method.

• Journal of Nutrition and Health
• /
• v.8 no.1
• /
• pp.15-37
• /
• 1975

I. Subject of the study A study on the nutritive value and utilization of powdered seaweeds. II. Purpose and Importance of the study A. In Korea the shortage of food will be inevitable by the rapidly growing population. It will be very important study to develop a new food from the seaweeds which were not used hitherto for human consumption. B. The several kinds of seaweeds have been used by man in Korea mainly as side-dishes. However, a properly powdered seaweed will enable itself to be a good supplement or mixture to certain cereal flours. C. By adding the powdered seaweed to any cereals which have long been staple foods in this country the two fold benefits; saving of cereals and change of dietary pattern, will be secured. III. Objects and scope of the study A. Objects of the study The objects will come under four items. 1. To develop a powdered seaweed as a new food from the seaweeds which have been not used for human consumption. 2. To evaluate the nutritional quality of the products the analysis for chemical composition and animal feeding experiment will be conducted. 3. Experimental cocking and accepability test will be conducted for the powdered products to evaluate the value as food stuff. 4. Sanitary test and also economical analysis will be conducted for the powdered products. B. Scope of the study 1. Production of seaweed powders Sargassum fulvellum growing in eastern coast and Sargassum patens C.A. in southern coast were used as the material for the powders. These algae, which have been not used for human consumption, were pulverized through the processes of washing, drying, pulverization, etc. 2. Nutritional experiments a. Chemical composition Proximate components (water, protein, fat, cellulose, sugar, ash, salt), minerals (calcium, phosphorus, iron, iodine), vitamins (A, $B_1,\;B_2$ niacin, C) and amino acids were analyzed for the seaweed powders. b. Animal feeding experiment Weaning 160 rats (80 male and 80 female rats) were used as experimental animals, dividing them into 16 groups, 10 rats each group. Each group was fed for 12 weeks on cereal diet (Wheat flour, rice powder, barley powder, potato powder, corn flour) with the supplementary levels of 5%, 10%, 15%, 20% and 30% of the seaweed powder. After the feeding the growth, feed efficiency ratio, protain efficiency ratio and ,organs weights were checked and urine analysis, feces analysis and serum analysis were also conducted. 3. Experimental cooking and acceptability test a. Several basic studies were conducted to find the characteristics of the seaweed powder. b. 17 kinds of Korean dishes and 9 kinds of foreign dishes were prepared with cereal flours (wheat, rice, barley, potato, corn) with the supplementary levels of 5%, 10%, 15%, 20% and 30% of the seaweed powder. c. Acceptability test for the dishes was conducted according to plank's Form. 4. Sanitary test The heavy metals (Cd, Pb, As, Hg) in the seaweed powders were determined. 5. Economical analysis The retail price of the seaweed powder was compared with those of other cereals in the market. And also economical analysis was made from the nutritional point of view, calculating the body weight gained in grams per unit price of each feeding diet. IV. Results of the study and the suggestion for application A. Chemical composition 1. There is no any big difference in proximate components between powders of Sargassum fulvellum in eastern coast and Sargassum patens C.A. in southern coast. Seasonal difference is also not significant. Higher levels of protein, cellulose, ash and salt were found in the powders compared with common cereal foods. 2. The levels of calcium (Ca) and iron (Fe) in the powders were significantly higher than common cereal foods and also rich in iodine (I). Existence of vitamin A and vitamin C in the Powders is different point from cereal foods. Vitamin $B_1\;and\;B_2$ are also relatively rich in the powders.'Vitamin A in ·Sargassum fulvellum is high and the levels of some minerals and vitamins are seemed4 to be some influenced by seasons. 3. In the amino acid composition methionine, isoleucine, Iysine and valine are limiting amino acids. The protein qualities of Sargassum fulvellum and Sargassum patens C.A. are seemed to be .almost same and generally ·good. Seasonal difference in amino acid composition was found. B. Animal feeding experiment 1. The best growth was found at.10% supplemental level of the seaweed Powder and lower growth rate was shown at 30% level. 2. It was shown that 15% supplemental level of the Seaweed powder seems to fulfil, to some extent the mineral requirement of the animals. 3. No any changes were found in organs development except that, in kidney, there found decreasing in weight by increasing the supplemental level of the seaweed powder. 4. There is no any significant changes in nitrogen retention, serum cholesterol, serum calcium and urinary calcium in each supplemental level of the seaweed powder. 5. In animal feeding experiment it was concluded that $5%{\sim}15%$ levels supplementation of the seaweed powder are possible. C. Experimental cooking and acceptability test 1. The seaweed powder showed to be utilized more excellently in foreign cookings than in Korean cookings. Higher supplemental level of seaweed was passible in foreign cookings. 2. Hae-Jo-Kang and Jeon-Byung were more excellent than Song-Pyun, wheat cake, Soo-Je-Bee and wheat noodle. Hae-Je-Kang was excellent in its quality even as high as 5% supplemental level. 3. The higher levels of supplementation were used the more sticky cooking products were obtained. Song-Pyun and wheat cake were palatable and lustrous in 2% supplementation level. 4. In drop cookie the higher levels of supplementation, the more crisp product was obtained, compared with other cookies. 5. Corn cake, thin rice gruel, rice gruel and potato Jeon-Byung were more excellent in their quality than potato Man-Doo and potato noodle. Corn cake, thin rice gruel and rice gruel were excellent even as high as 5% supplementation level. 6. In several cooking Porducts some seaweed-oder was perceived in case of 3% or more levels of supplementation. This may be much diminished by the use of proper condiments. D. Sanitary test It seems that there is no any heavy metals (Cd, Pb, As, Hg) problem in these seaweed Powders in case these Powders are used as supplements to any cereal flours E. Economical analysis The price of the seaweed powder is lower than those of other cereals and that may be more lowered when mass production of the seaweed powder is made in future. The supplement of the seaweed powder to any cereals is also economical with the criterion of animal growth rate. F. It is recommended that these seaweed powders should be developed and used as supplement to any cereal flours or used as other food material. By doing so, both saving of cereals and improvement of individual's nutrition will greatly be achieved. It is also recommended that the feeding experiment for men would be conducted in future.

• Korean Journal of Materials Research
• /
• v.29 no.11
• /
• pp.727-733
• /
• 2019

In this study, the glass melting properties are evaluated to examine the possibility of using refused coal ore as replacement for ceramic materials. To fabricate the glass, refused coal ore with calcium carbonate and sodium carbonate in it (which are added as supplementary materials) is put into an alumina crucible, melted at $1,200{\sim}1,500^{\circ}C$ for 1 hr, and then annealed at $600^{\circ}C$ for 2 hrs. We fabricate a black colored glass. The properties of the glass are measured by XRD (X-ray diffractometry) and TG-DTA (thermogravimetry-differential thermal analysis). Glass samples manufactured at more than $1,300^{\circ}C$ with more than 60 % of refused coal ore are found by XRD to be non-crystalline in nature. In the case of the glass sample with 40 % of refused coal ore, from the sample melted at $1,200^{\circ}C$, a sodium aluminum phosphate peak, a disodium calcium silicate peak, and an unknown peak are observed. On the other hand, in the sample melted at $1,300^{\circ}C$, only the sodium aluminum phosphate peak and unknown peak are observed. And, peak changes that affect crystallization of the glass according to melting temperature are found. Therefore, it is concluded that glass with refused coal ore has good melting conditions at more than $1,200^{\circ}C$ and so can be applied to the construction field for materials such as glass tile, foamed glass panels, etc.

• Journal of Nutrition and Health
• /
• v.11 no.1
• /
• pp.1-8
• /
• 1978

Ninety-three weaning children, 8-36 Mo. old wererandomly selected from rural areas of South Korea. Food and nutrient intake level were measured by the weighing-interview method for two consecutive days in December 1976. Their weaning pattern, dietary pattern, food and nutrient intake level were analyzed. A brief summary of 4he finding follows; 1) 80% of the rural children completed the weaning by the age of 24 months. 2) 44% of 8-12 month olds were living only on breast mil while the rest of the age group received regularly a supplementary food. 3) Over half of the 8-36 Mo old children investigated were receiving the same dietary pattern, arbitrarily called 'Diet K'. Diet K consists of rice-Kimchi-seasoning-oil which is the basic components of an average Korean adult diet. This very composition of the diet K and no other variety of food included inevitably result in low intake of vitamin A, iron, calcium and riboflavin for the children. 4) The weaning children were found to be taking all nutrients except niacin in amount far from sufficient to recommended level. Particularly low were the intakes of good quality protein, iron, vitamin A, riboflavin and vitamin C which met only 15%-37% of the recommended level for 12-36 Mo. olds. 5) It was concluded that majority of the rural children of weaning age in Korea are given the simple diet K and feeding the weaning children only with the basic dietary pattern of adults can not meet the nutritional requirements. This is a part of the study supported by the ROKG/USAID Health Planning Project.

• Korean Journal of Agricultural Science
• /
• v.43 no.2
• /
• pp.232-239
• /
• 2016

Recently, research has been focusing on high quality and safer animal production by utilizing natural functional materials. The aim of this study was to evaluate the effect of administration of natural Evening Primrose Oil (EPO) on gamma linolenic acid (GLA) levels in milk from Holstein dairy cows. Quality and quantity of milk as well as blood and fatty acids from Holstein cow fed diets supplemented with 2.7-4% calcium-salted EPO coated with palm stearin oil were analyzed. There was no significant difference in yield and composition of milk between control and EPO treatment. However, EPO treatment lowered blood aspartate aminotransferase (AST), somatic cell count (SCC), and cholesterol levels (p < 0.05) compared to untreated control. Blood urea nitrogen (BUN) level was decreased (p < 0.05) in GLA 1 and GLA 2 group when compared with control group. Non-esterified fatty acids (NEFA) concentration was lower (p < 0.05) in GLA 1 and GLA 2 groups than in control group. The level of GLA in milk was increased in EPO group when compared to control. Therefore, results from the present study demonstrate that supplementary EPO has beneficial effects on cow health, showing a decrease in somatic cell count and levels of blood cholesterol, alanine aminotransferase (ALT), and AST. Furthermore, supplementation of EPO improves milk quality with increased amounts of GLA.

• Korean Journal of Community Nutrition
• /
• v.1 no.3
• /
• pp.335-345
• /
• 1996

The solids(supplementary food) consumption of 200 healthy infants aged from 4 to 6 months have been measured. Five groups were assigned to different feeding patterns. Breastfed group(BF, n=38), formula-fed group(FF, n=102) and mixed-fed group(MF, n=14) were fed breast milk, formula and mixed(breast mile+formula) from birth until 6 months of age respectively. Convert 1 group(C1F, n=14) and convert 2 group(C2F, n=32) were fed breast milk and mixed milk at 2 months of age respectively and were switched to formula thereafter. All infants received solids form 4 months of age. The energy intake from solids at 4 and 6 months averaged 59.1 and 110.3㎉/d among BF groups vs 151.9 and 239.3㎉/d among FF groups respectively. Intakes of protein, calcium and iron were 38-46$\%$, 34-44% and 25-37$\%$ higher in the FF than in the Bf group during the first 6 months. However, no significant differences were found in the intakes of energy and nutrient intakes from solids in all 4 groups excluding BF group(39$\%$). Although BF infant's nutrient intakes from solids were lower than other group's intakes, they intaked evenly solids from various food groups. As the age of infant had increased, the energy intake ratio from solids was cereals and dairy products was increased whereas energy intake ratio from meats, eggs, fruits and vegetables was decreased. TSC4, TSC6(the frequency score for the kinds of weaning food taken) showed no significant difference among 5 feeding groups but CIF-and C2F group's scores tended to be high. Consequently, these results suggest that BF group's solid intake pattern is more desirable and that Korean lactating Mother's dependence on commercial weaning food is too high.

• Korean Journal of Community Nutrition
• /
• v.18 no.1
• /
• pp.1-10
• /
• 2013

This study investigated the effect of nutritional improvement of 1-5 year children participated in NutriPlus program. The program was carried out at Public health Center, Daedeok-gu, Daejeon from March 2009 to April 2011. The subjects were selected among applicants for low-income family financing of the government and included 90 children and their parents. they were divided into 2 groups (less than 6 months and more than 6 months of participation in the study). We analyzed the effects of NutriPlus program and nutrition education in both study groups. The results of this study were summarized as follows: The number of children with less than 10th percentile in height and weight and weight for height was decreased. The anemia prevalence rate was reduced from 64.4% to 8.9%. NAR value of subjects increased for energy, protein, calcium, iron, vitamin A, riboflavin, niacin and vitamin C. The education program improved knowledge and attitude of the parents. In nutrition knowledge according to the income level, there were greater changes in the group of less than 100% compared to the subsistence. In nutrition attitude according to the education level, there were greater changes in the group of middle school graduates than in high school graduates or college graduates. There were no difference between less than 6 months group and more than 6 months group in improvement of hemoglobin level, anthropometric data and nutrients intakes. Based on these results, we conclude that providing supplementary food to children and nutrition education brought positive effects on growth of the children.