• Computers and Concrete
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• 제8권3호
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• pp.279-292
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• 2011

The main purpose of this study includes investigation of the rheological properties of fresh self consolidating cement paste containing chemical and mineral additives using Artificial Neural Network (ANN) model. In order to develop the model, 200 different mixes are cast in the laboratory as a part of an extensive experimental research program. The data used in the ANN model are arranged in a format of fourteen input parameters covering water-binder ratio, four different mineral additives (calcium carbonate, metakaolin, silica fume, and limestone), five different superplasticizers based on the poly carboxylate and naphthalene and four different Viscosity Modified Admixtures (VMAs). Two common output parameters including the mini slump value and flow cone time are chosen for measuring the rheological properties of fresh self consolidating cement paste. Having validated the model, the influence of effective parameters on the rheological properties of fresh self consolidating cement paste is investigated based on the ANN model outputs. The output results of the model are then compared with the results of previous studies performed by other researchers. Ultimately, the analysis of the model outputs determines the optimal percentage of additives which has a strong influence on the rheological properties of fresh self consolidating cement paste. The proposed ANN model shows that metakaolin and silica fume affect the rheological properties in the same manner. In addition, for providing the suitable rheological properties, the ANN model introduces the optimal percentage of metakaolin, silica fume, calcium carbonate and limestone as 15, 15, 20 and 20% by cement weight, respectively.

• 대한소아치과학회지
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• 제51권2호
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• pp.140-148
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• 2024

This study aimed to enhance the physicochemical properties of sodium iodide-based root filling materials, particularly solubility. In earlier developmental stages, the iodoform-containing paste exhibited high antibacterial efficacy but failed to meet only the solubility requirement among the ISO 6876 criteria. Therefore, this study focused on enhancing the physicochemical properties of the paste under development, particularly centering on reducing its solubility. Four experimental groups were established, including three control group. The previously developed D30 paste was named the Oil 33 group, and the control group was named the Vitapex^® group. The Oil 50 group, in which the oil content was increased, and the Oil 45L group, in which lanolin was incorporated. The physical properties (solubility, pH, flowability, and film thickness) of the four pastes were evaluated according to the ISO 6876 standards. No significant differences were observed between the Oil 45L and Vitapex^® groups in any of the physical property evaluations. While the Oil 33 and Oil 50 groups met the ISO 6876 standards for flowability and film thickness, the Oil 45L group met all the physical properties. However, reducing the overall oil content may be necessary to enhance the antimicrobial properties. The result of the physicochemical experiments showed that the Oil 45L group with the newly formulated composition and incorporated lanolin exhibited low solubility meeting the ISO 6876 standard of ≤ 3%. We were able to develop a paste with more stable solubility than previous iodide-based root-filling materials. Therefore, the oil content must be further adjusted to improve its antimicrobial properties. If other physical properties also meet the ISO 6876 standards and demonstrate excellent results in cytotoxicity tests, this root filling material could potentially replace existing options.

• Tribology and Lubricants
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• 제28권2호
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• pp.93-98
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• 2012

The engine oil is an oil used for lubrication of various internal combustion engines. Recently, the vehicle and engine oil manufacture usually guarantee for oil change over 15000~20000 km mileage, but the most of driver usually change engine oil every 5000 km driving in Korea. In this case, it is possible to cause environmental contamination by used engine oil and increase the cost of driving by frequently oil change. In this study, we investigate the various physical properties such as flash point, pour point, kinematic viscosity, cold cranking simulator, total acid number, and four-ball test for fresh engine oil and used engine oil after vehicle driving (5000 km, 10000 km). The test result showed that the total acid number and wear scar by four-ball test of used engine oil had increased than fresh engine oil, but 2 kind of used oil (5000 km and 10000 km) had similar physical properties.

• 한국농공학회논문집
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• 제52권4호
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• pp.63-71
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• 2010

This study was performed to evaluate the planting properties and root potential of planting block with mixing seeding of herbaceous plants and cool-season grasses in CSG blocks manufactured by cemented sand and materials (CSG) in order to develop environmentally friendly CSG block applied revegetation. Five types of CSG mix designs with cement contents were determined, and the mechanical properties of CSG materials were studied experimentally. To analyze growth properties of plants within CSG block, germination ratio, visual cover, plant height and root potential were measured in four weeks and eight weeks after seeding. The germination regardless mixture seeding of plants and CSG mixproportions started within 4 ~ 7 days after seeding and the germination ratio were in the range of 60 ~ 65 %. The visual cover of kinds of plants evaluated by visual rating system were in the range of 6 ~ 8 in case of seeding the species of cool-season grasses and were in the range of 4 ~ 6 in case of seeding the species of herbaceous plants in four weeks after seeding. The root potential of CSG block with the species of cool-season grasses and herbaceous plants were in the range of $5.7{\times}10^{-3}{\sim}7.7{\times}10^{-3}$ MPa and $2.3{\times}10^{-3}{\sim}6.7{\times}10^{-3}$ MPa in eight weeks after seeding, respectively.

• 한국식품영양과학회지
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• 제28권6호
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• pp.1269-1274
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• 1999

Four dimensional response surface methodology was applied to determine the optimum conditions on organoleptic properties to develop red pepper jam into Korean type jam. The organoleptic color of red pepper jam showed maximum score of 8.08 in 14.24g pectin, 256.2g sucrose and 8.31ml citric acid(50% citric acid solution). The organoleptic taste of red pepper jam showed maximum score of 6.77 in 14.23g pectin, 202.1g sucrose and 8.19ml citric acid. Optimum conditions on the organoleptic mouth feel of red pepper jam were 14.34g in pectin, 255.6g in sucrose and 8.39ml in 50% citric acid solution. Maximized overall palatability of red pepper jam was 7.25 in 14.15g pectin, 257.08g sucrose and 8.19ml of 50% citric acid solution. The optimum preparation condition ranges on organoleptic properties of red pepper jam were 14.0~15.5g pectin, 225.0~257.0g sucrose and 8.0~8.2ml of 50% citric acid solution.

• 한국의류산업학회지
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• 제8권5호
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• pp.585-590
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• 2006

In the variation of physical properties of adhesive fabrics, the objective of this study is to analyze fitness of fusible interlining to four sorts of fabrics for men's suit with various structural parameters. Four fusible interlinings are used for adhering to fabrics for men's suit. Mechanical properties of these 16 adhesive fabrics fused with these interlinings are measured by KES-FB system for analysing appearance and wearing properties of garments and for examining the fitness of fusible interlining to the fabrics for men's suit. The variation of bending property for adhesive fabrics are found to be higher in the order of interlining 1(Cotton30/Rayon70, plain), interlining 2(Polyester30/Rayon70, warp knit), interlining 4(Polyester, shingosen fabrics with drawing textured yarn) and interlining 3(Polyester, double dot coating interlining). The variation of adhesive effect shows the same results with bending property and shows negative relation with extensibility in weft direction per extensibility in warp direction(EM2/EM1). The variation of peel strength of adhesive fabrics, woolen fabrics in the case of face fabrics and interlining 3 in the case of interlining shows the largest value respectively.

• Natural Product Sciences
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• 제26권4호
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• pp.345-350
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• 2020

In recent years, tyrosine kinases (TKs) have been the target to combat cancers, and most of the developed inhibitors are of synthetic origin. Natural compounds that have the properties as the TK's inhibitors are very limited. This paper described the isolation of a new dammarane triterpene from the tree bark of Sandoricum koetjape, along with three known related dammaranes from the damar resin of Shorea javanica, as well as their inhibitory properties against eight receptor TKs (RTKs: EGFR, HER2, HER4, IGF1R, InsR, KDR, PDGFRα, and PDGFRβ). Based on the NMR and mass spectral data the new compound was identified as (12β,20S)-12,20-dihydroxy-3,4-seco-dammaran-4,24-dien-3-oic acid (12β-hydroxydammarenolic acid) (1), while the three known compounds were identified as (20S)-20-hydroxy-3,4-seco-dammaran-4,24-dien-3-oic acid (dammarenolic acid) (2), (3β,20S)-3,20-dihydroxydammaran-24-ene (3), and (20S)-3-oxo-20-hydroxydammaran-24-ene (4). The tyrosine kinase assay of the four compounds resulted only 1 and 2 at concentration of 10 μM that had weak activity against EGFR and InsR, with their % inhibitory were 30%, 27% (1), 45%, and 32% (2), respectively. The results suggested that the presence of a linear carboxylic acid group in both compounds could be of significance to the inhibitory properties against the two RTKs.

• 한국염색가공학회지
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• 제18권3호
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• pp.49-58
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• 2006

The purpose of this study was to examine the effect of covering yarn's twist on mechanical properties of knitted fabrics of composite yarns with single covering process. Four yarns that were used in this study: two different composite yarns made from the four kinds of cotton and functional polyester-(Poly-A) with the ratio of 52:48, and the rest two yarns are the original cotton 100% yarn and the poly-A 100% yarn. The two kinds of composite yarns, CP1 and CP2, were processed on the single covering process. CP1 was applied on the single covering process with S-800 tpm, where Poly-A was used as covering yarn and cotton was used as core yarn. CP2 was applied on the same process as CP1 except that Poly-A had been applied on the two-for-one twisting process with S-400 tpm on the previous step. Sixteen mechanical properties of all the four knifed fabrics knitted under the same knitting conditions were measured by KES-FB system with the outer knit condition. And 3D CAD dressmaking simulations, which were driven by some of the mechanical properties, were presented. The results were as follows: CP2 had high RT values with twisting of covering yarn. CP2 also had high B, 2HB values because of higher linear density. SMD was affected rather by twisting of covering yarn than by fine hair of the cotton surface. Twisting of covering yarn made it decreasing T value and increasing W value. Dressmaking 3D CAD simulations showed that there are buckling effects on CP2 because of high bending rigidity and shear rigidity.

• 터널과지하공간
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• 제25권3호
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• pp.231-243
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• 2015

본 연구에서는 최근 재개발되고 있는 정선지역의 철광산에서 현장 초기지압 시험과 수많은 암석 실내시험을 실시하였다. 본 광산의 측압계수는 심도가 깊어질수록 작아지는 경향을 보였으며 평균값은 1.10으로 나타났다. 본 광산에 주로 분포하는 네 가지 암종인 백운암, 규장암, 화강암, 철광석에 대한 실내시험을 통해 암석의 단위중량, 공극률, 흡수율, 탄성파속도, 일축압축강도, 영률, 포와송비, 인장강도, 쇼어경도, 내부마찰각, 점착력 등의 각종 역학적 특성을 조사하였다. 실내시험 결과의 통계분석을 통해 암종별 물성을 비교하였고 물성 상호간의 관련성을 검토하였는데, 철광석보다는 규장암이나 화강암의 강도특성이 더 컸으며 암석 물성 간의 일반적인 상관관계와는 반대되는 현상도 발견되었다. 또한 Mohr-Coulomb 파괴조건과 Hoek-Brown 파괴조건을 적용하여 네 가지 암석의 파괴조건을 해석하였다.

• 한국의류산업학회지
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• 제11권4호
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• pp.641-647
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• 2009

The purpose of this study was to evaluate the physical properties and handle of knitwears made with silver yarns. The four different knitted fabrics were made and compared: cotton(C), cotton/silver(CS), polyester(P), and polyester/silver(PS). If fabrics knitted with silver combined yarns, their electrical shield properties, UV-cut properties, anti-static properties, and air permeability were improved. As an additional effect this also improves the antibacterial properties of fabrics. It was found that overall physical properties and functional properties were improved by using silver yarn with cotton. The silver knitted fabric was found to be improved its softness and fullness hand for apparel.