• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4A
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• pp.767-774
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• 2006

This study has focused on the possibility for recycling of tailings from the sangdong tungsten mine as powder (TA) of self-compacting concrete (SCC). The experimental tests for entrapped water ratio were carried out in accordance with the specified method by Okamura. The rheological measurements of cement paste were conducted by using a commercially digital Brookfield viscometer (Model LVDV-II+) equipped with cylindrical spindles, also tests for slump-flow, time required to reach 500 mm of slump flow (sec), time required to flow through V-funnel (sec) and filling height of U-box test (mm) were carried out in accordance with the specified by the Japanese Society of Civil Engineering (JSCE). The results of this study, entrapped water ratio was decreased with increasing replacement of TA. Thickness of pseudo water film was increased, and mean plastic viscosity was decreased with increasing replacement of TA. And slump-flow of SCC was decreased with increasing replacement of TA. But time required to reach 500 mm of slump flow (sec), time required to flow through V-funnel (sec) and filling height of U-box test (mm) were satisfied a prescribed range. The mechanical properties including compressive strength, splitting tensile strength and elastic modulus were checked with the requirements specified by Korean Industrial Standard (KS). The compressive strength of SCC was decreased with increasing replacement of TA, splitting tensile strength and elastic modulus were similar to those of normal concrete.

• Korean Journal of Veterinary Service
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• v.14 no.2
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• pp.87-103
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• 1991

The somatic cell counts SCC and bacteria counts were done by D milk plant, P milk plant, S milk plant and Inch'${\v{\times}}n$ Vet. Serv. Lab from 1987 to 1990 with Coulter counter, Fossomatic 90, Bactoscan, Rolling ball viscometer and Resazurin reduction test. The results were summarized as follows 1. In the distribution of SCC of the bulk herd milk, D milk plant from Nov. 1989 to Oct. 1990 remarks 80.2% on the range below 500, 000, 14.5% ranging from 1, 000, 000 to 1, 500, 000, 1.2% ranging from 1, 500, 000 to 2, 000, 000, 0.69% ranging from 2, 000, 000 to 3, 000, 000, 0.71% on the range over 3, 000, 000. P milk plant remarks 237, 000 in the first half year and 251, 000 in the second half year in 1990 year. S milk plant remarks annual average of 335, 000 in 1987, 273, 000 in 1988 and 262, 000 in 1989. The individual record of Inch'${\v{\times}}n$ Vet. Serv Lab. remarks 79.35% and 80.2% below 500, 000 8.30% and 7.40% from 500, 000 to 1, 000, 000, 2.37% and 3.2% from 1, 000, 000 to 1, 500, 000, 2.77% and 2.30% from 1, 500, 000 to 2, 000, 000, 1.67% and 2.00% from 2, 000, 000 to 3, 000, 000, 5.53% and 4.40% over 3, 000, 000 in 1989 and 1990, respectively. The grade distirbution of SCC is as follows: D milk plant shows 1st grade-80.20%, 2nd grade-l6.5% and 3rd grade-3.30%. And P milk plant shows all 1st grade. S milk plant shows 87.30%, 8.6% and 4.1% in 1987 and 91.90%, 6.1% and 2.0% in 1988, and 92.40%, 6.1% and l.5% in 1989 on the 1st, 2nd and 3rd grade respectively. 2. The distribution of bacteria P milk plant reached 15.123 in 1st half year and 21.515 in 2nd half year. Also, S milk plant reached 81.5%, 12.5%, 6.0% in 1987, and 86.20%, 9.70%, 4.1% in 1988, and 86.2%, 10.8%, 3.0% in 1989 respectively for 1st, 2nd and 3rd grade. 3. The regional SCC distribution in D milk plant shows 1, 540, 000 in three regions and 714, 000 in one region. And monthly SCC distribution shows 671, 000 in December and 1, 165, 000 in June. 4. As a result of the individual SCC test, 9 times for 16 cows in “I”farm(1986-1988), and 6 times for 13 cows in“D”farm(1987-1988) No.3, 5, 9, 14 cows in“I”farm showed the high SCC beyond 1, 000, 000 over 4-5times. 5. If the SCC over 300, 000 reach 40%, the national producing quality of milk can be reduced by 87, 600M /I annually and in the sum of money, it should be about 35.5 billion Won. 6. The difference between high group and low group for SCC in D milk plant reached over 1, 000, 000. In case that the difference reaches 1, 000, 000 in the farm bulk milk at a farm breeding 20 cows which produce 20kg milk per day, it was estimate that the annual difference of producing quantity and sum of money respectively should be reached 26, 280kg in milk and 10, 643, 400 Won in income.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.834-842
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• 2000

In order to investigate the characteristics of various sweet potato starches, gelatinization temperatures, solution viscosity of starch separated from two cultivars of the dry type sweet potatoes(Yulmi and Gunmi), one cultivar of moist type sweet potato(Jinmi), and one cultivar of purple colored variety(Jami) were compared, and properties of the edible films prepared with the starches were determined. Under a differential scanning colorimetry(DSC), initial temperatures for starch gelatinization of the dry type sweet potatoes (Yulmi and Gunmi) were higher than that of the moist type sweet potato (Jinmi), and that of Jami was close to those of the dry type ones. The sweet potato starch solutions tested by a cone and plate viscometer, showed peudoplastic characteristics. The moist type sweet potato was the most viscous followed by Jami, Yulmi, and Gunmi among the tested starch solutions. Total color difference of the edible films prepared with different cultivars of sweet potatoes showed appreciable differences between cultivars, caused by differences in Hunterb values. Water Vapor Permeability (WVP) of sweet potato starch films also showed significant differences between cultivars. Films prepared with the dry type sweet potato, Gunmi, showed the lowest WVP value of $0.83{\times}10^{-9}\;g\;{\cdot}\;m/m^{2}\;{\cdot}\;s\;{\cdot}\;Pa$, followed by Jami, Yulmi, and Jinmi. Water solubility of the films did not show any significant differences between cultivars. Tensile strength of the dry type sweet potato and Jami, which ranged 14.18-18.75 MPa, were higher than that of the moist type sweet potato, which was 4.66 MPa. Elongation values of the films, which were 5-6%, indicated that sweet potato starch films were not so elastic.

• Journal of the Korean Applied Science and Technology
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• v.35 no.1
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• pp.173-185
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• 2018

Effects of three different types of dispersions and flow improving additives composed with fatty acid esters, fatty acid metal salts and amide compound on the vulcanization and the mechanical properties properties of rubber compounds of EPDM and carbon black as fillers. were investigated using Mooney viscometer, moving die rheometer, hardness tester, and universal test machine. The aging characteristics of vulcanized EPDM compounds were also investigated. The Mooney viscosity measured at $125^{\circ}C$ showed a tendency to decrease in the order of amide type> metal salt type > ester type additive. Scorch time showed little or no difference with the addition of ester or metal salt type additives, but the amide type additive shortened a scorch time more than one minute. Rheological measurement data obtained at $160^{\circ}C$ showed that the vulcanization time was faster for metal salt type and amide type additive systems. Delta torque values of EPDM compound increased with metal salt type and amide type additives, but slightly decreased with ester type additive. The tensile strength of the EPDM compound was greatly improved when an ester type additive was added, but the amide type or metal salt type additive had no significant effect. The elongation was significantly improved for metal salt type additive, while the rest were not significantly affected. The tear strength of the EPDM compounds increased with the addition of all kinds of additives, and it increased remarkably in the case of metal salt type additive. Hardness of the EPDM compounds was nearly same value regardless of additive types. The thermal aging of the EPDM blend at $100^{\circ}C$ for 24 h showed little change in the case of metal salt type or amide type additive, but the elongation tends to decrease by 10-20% for all EPDM compounds containing additives.

• Korean Journal of Food Science and Technology
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• v.25 no.1
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• pp.15-21
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• 1993

Crude ${\beta}-glucan$ extracted from Barley was purified by stepwise enzyme treatment (Thermostable ${\alpha}-amylase$, amyloglucosidase, protease). The Intrinsic Viscosity $[{\eta}]$ of the purified ${\beta}-glucan$ was determined by Cannon Fenske Capillary Viscometer (size 50, Cannon Instruments, State, College pa.) at different pH (2, 4, 7, 9, 11) and various salt concentration (0.01 M, 0.03 M, 0.05 M, 0.07 M, 0.1 M and 0.2 M). The $[{\eta}]$ of purified ${\beta}-glucan$ was ranged from $0.997{\sim}2.290\;dl/g$. The $[{\eta}]$ of purified ${\beta}-glucan$ at both alkali, acid condition were lower than those at pH 7. However, the alkali condition of puified ${\beta}-glucan$ solution showed less $[{\eta}]$ than the acid condition of this solution. From 0 M to 0.2 M salt concentration, the $[{\eta}]$ of purified ${\beta}-glucan$ solution was decreased to 0.03 M then increased to 0.05 M NaCl and remained constant to 0.2 M NaCl. The chain stiffness parameter of purified ${\beta}-glucan$ was not affected by temperature from $15^{\circ}C$ to $65^{\circ}C$. The shear rates of various ${\beta}-glucan$ conditions were determined by Bohlin Rheometer (Lund, Sweden). The ${\beta}-glucan$ concentration of 1.0 g/dl and 2.0 g/dl behaved as Newtonian fluid. However, above the concentration of 3.0 g/dl ${\beta}-glucan$ solution, it showed thixotropic and psedoplastic characteristics. Barley ${\beta}-glucan$ appears a damping at 0.5 frequency for the 4.0 g/dl solution. Below 0.5 frequency, it appears a viscous behavior property and above 0.5 frequency, it appears a elastic behavior property.

• Journal of Oral Medicine and Pain
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• v.34 no.3
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• pp.227-235
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• 2009

Many of the protective functions of saliva can be attributed to the biological, physical, structural, and rheological characteristics of salivary glycoproteins. Therefore, the development of ideal saliva substitutes requires understanding of the rheological as well as biological properties of human saliva. In the present study, we investigated the changes of salivary enzymatic activities by saliva substitutes and compared viscosity of saliva substitutes with human saliva. Five kinds of saliva substitutes such as Moi-Stir, Stoppers4, MouthKote, Saliva Orthana, and SNU were used. Lysozyme activity was determined by the turbidimetric method. Peroxidase activity was determined with an NbsSCN assay. $\alpha$-Amylase activity was determined using a chromogenic substrate, 2-chloro-p-nitrophenol linked with maltotriose. The pH values of saliva substitutes were measured and their viscosity values were measured with a cone-and-plate digital viscometer at six different shear rates. Various types of saliva substitutes affected the activities of salivary enzymes in different ways. Stoppers4 enhanced the enzymatic activities of hen egg-white lysozyme, bovine lactoperoxidase (bLP), and $\alpha$-amylase. Saliva Orthana and SNU inhibited bLP activity and enhanced $\alpha$-amylase activity. MouthKote inhibited $\alpha$-amylase activity. Moi-Stir inhibited the enzymatic activities of bLP and $\alpha$-amylase. The pH values were very different according to the types of saliva substitutes. Stoppers4, MouthKote, and Saliva Orthana showed lower values of viscosity at low shear rates and higher values of viscosity at high shear rates compared with unstimulated and stimulated whole saliva. Moi-Stir and SNU displayed much higher values of viscosity than those of natural whole saliva. Collectively, our results indicate that each saliva substitute has its own biological and rheological characteristics. Each saliva substitute affects the enzymatic activity of salivary enzyme and finally oral health in different ways.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.18 no.1
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• pp.99-132
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• 1992

Polypeptide has been used broadly as an active ingredient in cosmetics We thought it is very important to investigate the adsorption behavior of polypeptide in order to pre-estimate the effect of these polypeptides. For the study of polypeptide adsorption, we have investigated complex formation of basic homopolypeptides, poly(L-proline) Form I [PLP(I)], Form II [PLP(II)] and poly(4-hydroxy-L-proline) (PHLP) with acidic homopolypeptides, poly(L-glutamic acid) (PLGA), poly(D-glutamic acid) (PDGA) and poly(L-aspartic acid) (PLAA) through hydrogen bonding in a hydroalcoholic medium with viscometer, 1ight scatter, pH meter and circular dicroism (CD). The polypeptides used in this study have helical structure in some conditions. The result exhibited that al 1 the complexes were formed as the composition of basic/acidic homopolypeptide : L:2 irrespective of the complex systems used. A more favorable complex is formed in the PLP(II)-PLGA system than PHLP-PLGA because PLP(II) has a more flexible helical conformation, whereas PHLP has a more rigid helical conformation. The right-handed helix PLGA formed the complex favorably and quickly with the left-handed helix PLP(II), whereas the left-handed helix PDGA formed the complex favorably with the right-handed helix PLP(I). The effect of side chain of the acidic homopolypeptides on the complexation was also studied. The result showed that more favorable condition for the complexation was PLGA-PLP(II) system which has longer side chain at acidic homopolypeptide than PLAA - PLP(II). All the above facts were well supported by CD measurement for the complex systems. By the CD spectra for the complexes we could deduce the conformational change of each homopolypeptide in the complexes On the basis of the above results, we performed the adsorption test of PLP(I, II) and PHLP on the hair having a left-handed helix. The adsorption amount of each polypeptide was analyzed by HPLC. The result showed that PLP(I) was adsorbed more than PLP(II), PLP(II) was adsorbed more than PHLP on the hair. On adsorbing polypeptides having a helical structure on the hair through hydrogen bonding, it could be concluded that the helical polypeptides having the opposite directional structure to the hair are adsorbed more than those having the same directional structure with the hair and also the polypeptides having a flexible conformation are adsorbed more than those having a rigid conformation.