• Journal of Nutrition and Health
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• 제28권1호
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• pp.5-14
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• 1995

The present study was performed to investigate the effect of cereal fiber on lipid concentration of liver and serum in rats. Male Sprague-Dawley rats weighing 180$\pm$4g were divided into five groups by completely randomized block design : R, BR, B, W, and F. Each group fed a diet containing 0.7% cholesterol and a kind of cereal among rice(R), brown rice(BR), barley(B), whole wheat(W), and wheat flour(F) for 5 weeks. The results were summarized as follow : 1) Food intake. weight gain and feed efficiency ratio were not significantly different among the groups. 2) Fecal wet weight and dry weight were significantly higher in W group which fed the most amount of IDF(insoluble dietary fiber). 3) The weight of large intestine was significantly heavier in the W group compared to the others. But the weights of liver, stomach and small intestine were not significantly different among the groups. 4) Total lipid. triglyceride(TG) and total cholesterol(TC) content in liver were significantly different among the groups. The values were the lowest in the B group whose intake of SDF(soluble dietary fiber) was the highest 5) TC content in serum was not significantly different among the groups. TG content in serum was significantly lower in the rest groups than in the R group. HDL-c and free-c content in serum were significantly higher in the B group than in the rest groups. HDL-c/LDL-c, free-c/ester-c ratio were the highest in the B group but not significant. Above results show that the dietary fiber contained in cereals has physiological effects and they are different depending on fractions, IDF and SDF.

• KIEAE Journal
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• 제15권4호
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• pp.45-52
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• 2015

Purpose: Foam concrete is the concrete that contains large amount of air voids inside. In general, the density of foam concrete depends on parameters like water/binder ratio, foam volume, aggregate and pozzolan content, etc. Method: In this study, the effect of foam volume and fly ash content on dry density is investigated intensively in order to find the relationship between each parameter and their abilities to counteract with each other. According to the above information, though there are quite a number of studies on the effect micro fiber on foam concrete at low volume fractions, there is still lack of information especially on the high fiber content side. The objective of the second study is to investigate further on the use of micro fiber at higher volume fraction and fill in the lacking information. Beside from this study, the investigation of the effect of micro-fiber (polypropylene) to enhance the properties of foam concrete is also carried out. Result: Of the two variables that are investigated in this study, the foam volume and the fly ash content, show significant effect on the properties of foam concrete. The foam volume tends to decrease the density and strength of foam concrete. In the second part of our study, a large fibre volume fraction is proved to be able to evidently increase the flexural strength of foam concrete up to about 40% due to the effect of fibre bridging over the crack and a significant number of fibres that intercepts the crack surfaces. However, the compressive strength is found to decrease severely due to the occurrence of large pores as the result of fibre being added into concrete mixture.

• International Journal of Concrete Structures and Materials
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• 제8권4호
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• pp.279-287
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• 2014

This paper presents the findings of an investigation of the fiber content variations in concrete being discharged from a ready-mix truck at the construction site. Concrete samples were extracted from the truck drums at the beginning, middle and end of discharge. Subsequently, fibers in each sample were separated from the concrete, and weighed. Presumably, synthetic macro fibers will float towards the top, i.e. towards the drum opening, of the inclined, revolving truck-drum, while, on the other hand, steel fibers will tend to gravitate towards the lower parts of the mixer drum. Accordingly, the discharge batch, containing synthetic macro fibers, will contain a higher amount of synthetic fibers per unit volume at the start of discharge than the average unit volume fiber content of the mix, and the content will gradually decrease further down the batch. The discharge batch of steel fiber concrete will contain fewer fibers per unit volume at the start of discharge than the average unit volume fiber content of the mix, and the content should gradually increase further down the batch. The correctness of the foregoing is partly confirmed. A certain percentage of the truck loads did not comply with the proposed requirements, mainly steel fiber reinforced batches, indicating the necessity of a code or guideline amendment. A change in the Norwegian shotcrete directive was made in 2011, based upon experimental research work (2010), which, in combination with the subsequent University of Life Sciences report (2012), constitutes the foundation of this article.

• 한국식품영양학회지
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• 제32권4호
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• pp.328-334
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• 2019

The objective of this study was to analyze proximate composition, dietary fiber, mineral content, fatty acid composition in Cheonggak (Codium fragile) in order to encourage the consumption of Cheonggak. The proximate composition of Cheonggak was found to be 5.51% moisture, 24.09% crude ash, 15.79% crude protein, 2.47% crude lipid and 45.31% dietary fiber. The major mineral content of Cheonggak was Na 8,950 mg/100 g, Mg 1,252 mg/100 g, Ca 807 mg/100 g, K 457 mg/100 g, and trace mineral content was Fe 26 mg/100 g, Mn 8 mg/100 g, Zn 0.4 mg/100 g. Palmitic acid 36.86% and ${\alpha}$-linolenic acid 20.14% were the most contained fatty acids in Cheonggak. The ratio of saturated fatty acids to unsaturated fatty acids was 85.49% while ${\omega}-6$ fatty acids to ${\omega}-3$ fatty acids were 59.10%. Based on the proximate composition, dietary fiber, mineral content, and fatty acid composition, Cheonggak was judged to be a major source of dietary fiber and Mg and Ca, and it was deemed to be helpful in promoting health, including the prevention of hyperlipidemia. Cheonggak contained valuable nutrients similar to seaweed, which is produced and consumed the most in Korea. Thus, it is necessary to include Cheonggak in the food items.

• 한국산업보건학회지
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• 제4권2호
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• pp.157-167
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• 1994

This study was conducted to analyze the relationship between the types of fiber and its content and the levels of airborne fiber concentrations at eight parking lots where sprayed insulation material was found on the walls and ceilings. Also this study was designed to find the relationship between the levels of airborne fiber concentrations and such variables as air current, humidity, total exhaust volume, surface condition of insulation material and building age. The results obtained were as follows : 1. No significant correlation was found between the levels of airborne tiber concentration and the building age, air current, humidity, total exhaust volume, space and the number of traffics. 2. A significant correlation was found between the levels of airborne fiber concentration and the MMMF content of the insulation material(r=0.7594). However, no significant correlation was found between the levels of airborne fiber concentration and total fiber content of insulation material. 3. The differences of the airborne fiber concentrations among Cateogory 1, 2 and 3 classified by the degrees of surface insulation material maintenance were very significant. 4. Two bulk samples contained 30% crodicolite and 1% anthophylite. The MMMFs, in all parking lots, included mineral wool, cellulose fiber, trace cellulose fiber, trace tiber glass and vermiculite. 5. The mean value and the range of airborne fiber concentrations at 8 parking lots were $0.0239{\pm}0.0095f/cc$ and 0.0054-0.0447 f/cc, respectively. The fiber concentrations of 35 out of 38 samples(92%) were over 0.01 f/cc which is the Environment Administration's recommended asbestos level for the underground space. This study suggests that most of building insulation materials used in Korea, contain MMMF and sometimes asbestos. Currently, MMMF pollution levels may exceed the Environment Administration's recommended level for underground space. It has been found that airborne fiber concentrations increased significantly with MMMF content and with the maintenance condition of surface material. Therefore, it is recommended that a proper management technique should be developed and immediately implemented since the conditions of surface material will be gradually deteriorated due to building age and usage. Since health hazards of the MMMF, similar to those of asbestos, are being gradually acknowledged, a proper management technique which is applicable to control total airborne fiber concentrations, both asbestos and MMMF, be developed and an acceptable indoor air standard be promulgated as early as possible.

• 접착 및 계면
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• 제19권2호
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• pp.60-67
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• 2018

본 연구에서는 친환경 천연섬유인 케나프의 표면을 Chemlok 402를 함유하고 있는 접착용액으로 전처리하였을 경우, 케나프/천연고무 복합재료의 경화거동, 경도, 인장특성 그리고 마모특성에 미치는 섬유 표면처리 유 무, 섬유함량 및 섬유길이의 영향을 조사하였다. 복합재료를 구성하는 케나프섬유 함량은 평균 케나프섬유의 길이가 약 2 mm로 일정한 상태에서 각각 0, 5, 10, 15, 20 phr로 달리하였다. 또한 섬유함량이 5 phr로 고정된 상태에서 평균 섬유길이는 각각 2 mm, 35 mm, 70 mm로 달리하여 각 특성을 비교하였다. 천연고무 복합재료의 경화거동을 나타내는 Tmax 값과 tc90 값, Shore A 경도, 인장탄성률 그리고 마모저항성은 케나프섬유 함량과 길이에 크게 의존하였다. 이러한 특성들은 케나프섬유의 표면을 접착용액으로 전처리한 경우가 처리하지 않은 경우보다 더 우수한 특성을 나타냈다. 이러한 현상은 전처리된 케나프섬유와 고무매트릭스 사이의 계면접착 상태가 개선되었기 때문이다. 본 연구결과는 천연섬유강화 복합재료의 물성을 향상시키기 위해 접착용액의 적절한 사용이 가능하다는 것을 제시하여 준다.

• 한국군사과학기술학회지
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• 제20권5호
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• pp.620-632
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• 2017

A chemical vapor curing method(CVC) was developed to cure polycarbosilane(PCS) fibers by using cyclohexene vapour as a non-oxygen active reactant, instead of air in oder to prepare the silicon carbide(SiC) fiber with low oxygen content. A cross-linked PCS fibers by cyclohexene vapor showed a completely different variation in IR spectra in comparison to the air-cured PCS fiber. CVC method resulted in less than 3 wt% in oxygen content. In this experiment conditions, The average tensile strength and modulus of SiC fiber obtained by CVC had 1995 MPa and 183 GPa respectively, which is higher than that of SiC fiber prepared by air-curing process.

• 한국세라믹학회지
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• 제56권5호
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• pp.513-520
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• 2019

This study reports the improvement of mechanical properties of Al₂O₃ porous ceramics from colloidal suspension with the addition of carbon fiber by direct foaming. The initial colloidal suspension of Al₂O₃ was partially hydrophobized by surfactant to stabilize wet foam with the addition of carbon fiber from 2 to 8 wt% as stabilizer. The influence of carbon fiber on the air content, bubble size, pore size and pore distribution in terms of wet foam stability and physical properties of porous ceramics were discussed. The viscosity of the colloidal suspension was increased giving solid like properties with the increased in carbon fiber content. The mechanical properties of the sintered porous samples were investigated by Hertzian indentation test. The results show the wet foam stability of more than 90% corresponds to compressive loading of 156.48 N and elastic modulus of 57.44 MPa of sintered sample with 8 wt% of carbon fiber content.

• Geomechanics and Engineering
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• 제30권5호
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• pp.461-469
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• 2022

One of the most important factors that should be considered for using any ground improvement technique is the stability of stabilized soil and the durability of the provided solution for getting the required engineering properties. Generally, most of the earth structures that are constructed on clayey soils are exposing movements due to the long periods of drying or wetting cycles. Over time, environmental changes may result in swells or settlements for these structures. In order to mitigate this problem, this research has been performed on mixtures of high plasticity clay with traditional additives such as lime, cement and non-traditional additives such as polypropylene fiber. The purpose of the research is to assess the most appropriate ground improvement technique by using commercially available additives for resisting the developed desiccation cracks during the drying process and resisting the volume changes that may result during wet/dry cycles as an attempt to simulate the changes of environmental conditions. The results show that the fiber-reinforced samples have the lowest volumetric deformation in comparision with cement and lime stabilized samples, and the optimum fiber content is identified as 0.38%. In addition, the desiccation cracks were not visible on the samples' surface for both unreinforced and chemically stabilized samples. Regarding cracks resistance resulting from the desiccation process, it is observed, that the resistance is connected with the fiber content and increases with the increase of the fiber inclusion, and the optimum content is between 1% and 1.5%.

• 한국농공학회논문집
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• 제46권6호
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• pp.13-19
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• 2004

This study was performed to evaluate permeable properties of eco-concrete using soil, natural coarse aggregate, soil compound and polypropylene fiber. The fIexural strength, ultrasonic pulse velocity and dynamic modulus of elasticity were increased with increasing the content of coarse aggregate, soil compound and polypropylene fiber. The flexural strength, ultrasonic pulse velocity and dynamic modulus of elasticity were 259 MPa, 3,527 m/s and 275 ${\times}$ 102 MPa at the curing age of 28 days, respectively. The coefficient of permeability was decreased with increasing the content of coarse aggregate and soil compound, but it was increased with increasing the content of polypropylene fiber. Accordingly, this concrete can be used for farm road.