Kim, Byungchul;Seo, Dong Hak;Chae, Heon-Seung;Shin, Seunghan
Applied Chemistry for Engineering
/
v.23
no.1
/
pp.18-22
/
2012
Photocurable binder for a transparent glass fiber composite was prepared with alicyclic methacrylate and fluorene-based diacrylate. ANOVA (analysis of variance) analysis was used to know main factors affecting the conversion of photocurable binder. It showed radiation intensity and photoinitiator (PI) concentration were main factors. The conversion of photocurable binder was simply increased with radiation intensity. Its increment however was abated with increasing PI concentration. We found that average conversion of the binder measured by FTIR-ATR was 87% when it was exposed to $5J/cm^2$ of UV dose with 5 wt% of PI. Oxime ester type PI was very effective to get a high degree of conversion, but it caused a yellowing problem. Owing to post-baking process, UV cured film showed an improved thermal stability by increase of conversion and removal of volatile organic compounds. TG% at $260^{\circ}C$ of film cured with 5 wt% of PI (TPO+MBF) and $5J/cm^2$ of UV radiation increased from 95.4 to 99.0% by post-baking at $230^{\circ}C$ for 5 min.
Objectives : Salvianolic acid B (SAB) is an active ingredient in Salvia miltiorrhiza frequently used for cardiovascular and cerebrovascular diseases. The present study investigated the antioxidant effects of SAB on the skeletal muscle and the brain tissue of rats following exhaustive exercise.Methods : The rats were treated with oral administration of SAB (30 mg/kg) daily for 5 days prior to the exhaustive exercise. The exhaustive exercise was performed as swimming for 150 min with 5% body weight attached to the tail on the 5th day. The antioxidant effects of SAB was evaluated by measuring the superoxide generation in the gastrocnemius and the 4-HNE expression in the hippocampal tissue. In addition, c-Fos-expressing cells in the brain tissue was observed using immunohistochemistry.Results : Histological features and muscle fiber type composition were not different between the SAB group and the exhaustive exercise group. SAB significantly reduced the upregulation of superoxide generation in the muscle tissue. SAB significantly reduced the increase of c-Fos-expressing cells in the cerebral cortex, paraventricular thalamic nucleus, dorsomedial hypothalamic nucleus, the CA1, CA3, and DG regions of hippocampus. SAB significantly reduced the upregulation of 4-HNE expression in the CA1 and DG regions of hippocampus caused by the exhaustive exercise.Conclusions : The results suggest that SAB exerts antioxidative effect against oxidative stress in the skeletal muscle and the brain tissue following exhaustive exercise, while SAB may has an anti-stress effect on stress responses in the brain.
Two hulled and two hull-less barley varieties were investigated for ${\beta}-glucan$ enrichment. Hull-less barleys contained higher levels of total ${\beta}-glucan$ than hulled barleys, and were thus suitable as starting materials for preparing ${\beta}-glucan-rich$ fractions. Particularly, a waxy type (Suweon-291) of hull-less barley was found to have high soluble dietary fiber content containing primarily ${\beta}-glucan$, compared to the other non-waxy barley varieties. ${\beta}-Glucan$ content of barley during pearling process was measured, and the highest value was observed at the pearling yield of approximately $70{\sim}75%$. The pearled barley grains were ground and sieved to yield ${\beta}-Glucan$ enriched fractions containing up to 22% ${\beta}-glucan$. In the meanwhile, whole barley samples were directly milled by $B{\ddot{u}}hler$ mill to produce bran, shorts, break flour and reduction flour. ${\beta}-Glucan$ contents in the bran and shorts from the milled stream were relatively high, and further concentration of ${\beta}-glucan$ could be accomplished by successive sieving of the bran and shorts fractions. Pearled barley and milled stream could be used to prepare barley fractions with ${\beta}-glucan$ concentrations $2.4{\sim}3.1$ times those of the original barley grain. Water solubility of barley ${\beta}-glucan$ from pearled barley and the milled stream was in the range of $40{\sim}81%$.
Aging and severe environments are major causes of damage in reinforced concrete (RC) structures such as buildings and bridges. Deterioration such as concrete cracks, corrosion of steel, and deformation of structural members can significantly degrade the structural performance and safety. Therefore, effective and easy-to-use methods are desired for repairing and strengthening such concrete structures. Various methods for strengthening and rehabilitation of RC structures have been developed in the past several decades. Recently, FRP composite materials have emerged as a cost-effective alternative to the conventional materials for repairing, strengthening, and retrofitting deteriorating/deficient concrete structures, by externally bonding FRP laminates to concrete structural members. The main purpose of this study is to investigate the effectiveness of adaptive neuro-fuzzy inference system (ANFIS) in predicting behavior of circular type concrete column retrofitted with FRP. To construct training and testing dataset, experiment results for the specimens which have different retrofit profile are used. Retrofit ratio, strength of existing concrete, thickness, number of layer, stiffness, ultimate strength of fiber and size of specimens are selected as input parameters to predict strength, strain, and stiffness of post-yielding modulus. These proposed ANFIS models show reliable increased accuracy in predicting constitutive properties of concrete retrofitted by FRP, compared to the constitutive models suggested by other researchers.
Journal of the Korean Society of Food Science and Nutrition
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v.43
no.12
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pp.1827-1834
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2014
Colon cancer is the third highest cause of death in Korea. Known dietary causes of colon cancer include a diet rich in fat and red meat as well as inadequate intake of dietary fiber, fruits, and vegetables. Therefore, recent research has focused on the anticancer effects of natural products. Opuntia humifusa is a type of prickly pear that is known to contain biologically active compounds that can be used in the treatment of diabetes mellitus, arteriosclerosis, and hyperglycemia. The aim of this study was to determine whether or not O. humifusa extract affects proliferation, cell death, and DNA fragmentation in human carcinoma HT-29 cells. O. humifusa is rich in carbohydrates, minerals (Mg, K, and Ca), and total phenolics. HT-29 cells were treated with extracts of O. humifusa at concentrations of 0, 0.25, 0.5, 1, and 2 mg/mL for 24 or 48 hours. O. humifusa extracts inhibited HT-29 cell growth in a dose-dependent manner. Hoechst 33342/PI double staining and Comet assay were performed to observe changes in nuclei of cancer cells undergoing cell death. The results of both tests showed that O. humifusa extract induced cell shrinkage, DNA fragmentation, and chromatin condensation dose-dependently in HT-29 cells. The results of this study suggest that O. humifusa extract inhibits the growth of HT-29 via induction of DNA fragmentation and chromatin condensation.
Kim, Chul-Hwan;Kim, Jae-Ok;Jung, Jun-Ho;Cho, Sung-Hwan
Journal of the Korean Society of Food Science and Nutrition
/
v.34
no.2
/
pp.298-305
/
2005
Antimicrobial packaging paper was prepared with a powder-type botanical antimicrobial agent from grapefruit seed extract (BAAG) and zeolite according to TAPPI standard method. The functional fillers containing BAAG fixed to CaCO$_3$ and zeolite were well retained in the fiber network by a retention aid such as cationic polyacrylamide, which was ascertained by the ash contents of paper and the SEM microphotographs. With addition of the functional fillers to paper, tensile strength and burst strength of the paper decreased by interference of the functional fillers with interfiber bonding but bending stiffness and tear strength increased by improved elastic modulus of paper and delayed transfer of tearing energy. Finally, it was confirmed that the antimicrobial packaging paper might be able to be used to make packaging bags and corrugated containers due to the minor deterioration of strength properties.
Proceedings of the Korean Geotechical Society Conference
/
2009.09a
/
pp.133-144
/
2009
Incheon Bridge, 18.4 km long sea-crossing bridge, will be opened to the traffic in October 2009 and this will be the new landmark of the gearing up north-east Asia as well as the largest & longest bridge of Korea. Incheon Bridge is the integrated set of several special featured bridges including a magnificent cable-stayed girder bridge which has a main span of 800 m width to cross the navigation channel in and out of the Port of Incheon. Incheon Bridge is making an epoch of long-span bridge designs thanks to the fully application of the AASHTO LRFD (load & resistance factor design) to both the superstructures and the substructures. A state-of-the-art of the geotechnologies which were applied to the Incheon Bridge construction project is introduced. The most Large-diameter drilled shafts were penetrated into the bedrock to support the colossal superstructures. The bearing capacity and deformational characteristics of the foundations were verified through the world's largest static pile load test. 8 full-scale pilot piles were tested in both offshore site and onshore area prior to the commencement of constructions. Compressible load beyond 30,000 tonf pressed a single 3 m diameter foundation pile by means of bi-directional loading method including the Osterberg cell techniques. Detailed site investigation to characterize the subsurface properties had been carried out. Geotextile tubes, tied sheet pile walls, and trestles were utilized to overcome the very large tidal difference between ebb and flow at the foreshore site. 44 circular-cell type dolphins surround the piers near the navigation channel to protect the bridge against the collision with aberrant vessels. Each dolphin structure consists of the flat sheet piled wall and infilled aggregates to absorb the collision impact. Geo-centrifugal tests were performed to evaluate the behavior of the dolphin in the seabed and to verify the numerical model for the design. Rip-rap embankments on the seabed are expected to prevent the scouring of the foundation. Prefabricated vertical drains, sand compaction piles, deep cement mixings, horizontal natural-fiber drains, and other subsidiary methods were used to improve the soft ground for the site of abutments, toll plazas, and access roads. Light-weight backfill using EPS blocks helps to reduce the earth pressure behind the abutment on the soft ground. Some kinds of reinforced earth like as MSE using geosynthetics were utilized for the ring wall of the abutment. Soil steel bridges made of corrugated steel plates and engineered backfills were constructed for the open-cut tunnel and the culvert. Diverse experiences of advanced designs and constructions from the Incheon Bridge project have been propagated by relevant engineers and it is strongly expected that significant achievements in geotechnical engineering through this project will contribute to the national development of the longspan bridge technologies remarkably.
The average specific cake resistance, the most important indicator for cake filtration and solid-liquid separation, is measured by filtration experiment. But the exact value is difficult to measure because of the other influences such as sedimentation during filtration. This study, a little more stable method named filtration-permeation is proposed for measuring average specific cake resistance. The filtration-permeation is composed of permeation of particle eliminated water through pre-formed cake by filtration. Using 1 wt% calcium carbonate suspension, the filtration-permeation experiments were performed for 8 kinds of filter media at the conditions of 0.5 atm and 0.2 atm, 1 and 3 sheets of filter media. At each specific condition, three to five times filtration-permeation were accomplished. As a result, stable permeation speed is measured. According to this experimental result, the characteristics of permeation and the effect of sedimentation are analyzed with Ruth's equation. The one way analysis of variance (one way ANOVA) is applied to the average specific cake resistances of filtration and permeation obtained with the selected three kinds of filter media. The average specific cake resistances between 0.5 atm and 0.2 atm by filtration do not distinguished, but those by permeation is perfectly distinguished. The experimental results during permeation have a very narrow distribution than that measured during filtration. The analysis of filtration experiments, it was verified that the resistance of filter medium by traditional method is of no significance. Finally, the migration of small particles through the medium composed of fiber glass at low pressure was studied.
Lee, Sang Hun;Kim, Sang Jin;Endo, Takao;Sagara, Yuzo
Journal of the Korea institute for structural maintenance and inspection
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v.15
no.1
/
pp.112-119
/
2011
Sheaths are arranged in the web and lower part of prestressed-concrete girder bridges, and prestressing wires and concrete are indirectly bonded together by filling interior parts of the sheaths. However, when the filling is not sufficient, water can penetrate the interior parts of the sheaths and, thereby, prestressing wires can be corroded or transverse cracks would occur around sheaths by the freezing and thawing action of the penetrated water. Therefore, it is an important element in maintenance management of structures to find out the sheaths unfilled with grout early after construction. In this paper, in order not to damage bridge members, the impact-echo method with a new approach in application is used to probe sheaths unfilled with grout for real structures. The location of sheaths is first estimated with reinforcing bar probing instrument of radar type and the measurement locations of sheaths are determined. By sending elastic wave to the side of girders and receiving the response, the location of the unfilled part of a sheath was estimated from the difference between high frequency peak and twice the resonance frequency indicating thickness. To verify the location of void estimated by the impact-echo method, pictures were taken by an industrial fiber scope after drilling a hole.
Kim, D.I.;Choi, J.R.;Cho, S.H.;Lee, D.H.;Chung, T.Y.
Journal of Animal Science and Technology
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v.46
no.5
/
pp.783-798
/
2004
This experiment were conducted to determine the formation of fatty acid soaps, digestibility and ruminal characteristics when vegetable oils were added. Three Corriedale${\times}$ 3 Latin square design. Sheep were fed one of three diets consisting of alfalfa hay and concentrates in a ratio of 70:30. Dietary treatments were 1) no oil, 2) 7% soybean oil and 3) 7% corn oil. At the end of each experimental period, rumen contents from each sheep were collected before feeding and at 1, 3, 6 and 9h after feeding. pH decreased up to the 3 hour after feeding and increased until the end of the collection(p<0.0001). Whereas the concentration of $NH_3$-N showed inverse changes to pH(p<0.0001). Type of oil did not affect the molar concentration of total VFA, acetate, propionate and butyrate. Acetic/propionic acid (A/P) ratio decreased with increasing time(P<0.0001), but the ratio at the end of the experiment became similar to the initial value. No effects were found in the digestibility of dry matter, total-N, crude fiber, ash, NFE, NDF and ADF. The formation of fatty acid soaps(FAS) increased after feeding than 1 hour before feeding(P<0.05) and increased in 7% oils than no oil addition(P<0.05). Long chain fatty acids formed mainly FAS. ince the formation of FAS might decrease negative effects on ruminal haracteristics and total tract digestibility.
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