• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1358-1366
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• 2006

In order to study the effects of shell contents on the liquefaction resistance of the shelly sand, NGI cyclic simple shear tests were performed for the shelly sands with shell contents of 0%, 5%, 10%, 20% and 30% under the effective vertical stress of 50kPa, 100kPa and 150kPa for 40% and 55% of relative density, respectively. Cyclic simple shear test results showed that for the low effective vertical stress, liquefaction resistance increased rapidly with the increase of shell contents in both 40% and 55% relative density. On the other hand, for the high effective vertical stress, the liquefaction resistance increased slightly in 40% relative density whereas the resistance was almost same in 55% relative density. Liquefaction resistance decreased with increasing effective vertical stress for both 40% and 55% relative density. In the same effective vertical stress and shell contents, liquefaction resistance increased with the increase of relative density of sands.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.6
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• pp.1226-1229
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• 1999

In order to investigate the harvest time for the production of high value added ark shell(Scapharca subcrenata) cultured at the south coast of Korea, the seasonal variations of proximate composition(mois ture, protein, fat, ash and glycogen) in the edible portions of ark shell were measured from December 1994 to December 1995. Moisture contents were the lowest in spring, but the highest in summer season being the spawning season of the S. subcrenata. The other hand, protein contents were a maximum in spring and minimum in summer. In June, just before the spawning season, fat and glycogen content was the highest, and ash content was little changed through a year. After spawning season, glycogen contents, showed decrement. In evaluating the seasonal variation of protein, moisture, and glycogen content in ark shell, the relationships of moisture protein content, moisture glycogen content and glycogen protein content show to be reverse.

• Journal of Environmental Science International
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• v.23 no.1
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• pp.153-156
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• 2014

This study was conducted to evaluate the effects of sea urchin shell powder on nitrogen characteristics in poultry litter by assigning ninety 1-d-old male broiler chicks (Arbor Acres) to one of 3 treatments (control, 1% sea urchin shell powder, and 1% feed additives) in 3 replicates of 10 birds each. For all treatments, the overall dry matter contents were decreased (P < 0.05) as time increased, except for at 1 week. When compared with controls, the dietary sea urchin shell powder and feed additives for 0 and 3 weeks did influence their TN contents, but not for 1, 2 and 4 weeks. The treatments with sea urchin shell powder and feed additives had a significant (P < 0.05) influence on $NH_3$-N in poultry litter compared with controls. However, at 4 weeks, no marked differences were observed in $NH_3$-N contents among treatments. Treatments with 1% sea urchin shell powder might enhance the value of poultry litter as N fertilizer.

• Journal of the Korean GEO-environmental Society
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• v.8 no.6
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• pp.69-76
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• 2007

The sands which use for soil improvement of soft ground at coastal area contain more or less amount of shells. In this research the effects of shell contents on the liquefaction resistance of the shelly sand were studied. NGI cyclic simple shear tests were performed for the shell-sands with shell contents of 0%, 5%, 10%, 20%, 30% under the effective vertical stress of 50kPa, 100kPa and 150kPa for 40% and 55% of relative density, respectively. Cyclic simple shear test results showed that for the low effective vertical stress, the liquefaction resistance increased rapidly with increase of shell contents in both 40% and 55% relative density. On the other hand, for the high effective vertical stress, the liquefaction resistance increased slightly in 40% relative density and was almost same in 55% relative density. Liquefaction resistance decreased with increasing effective vertical stress for both 40% and 55% relative density. In the same effective vertical stress and shell contents, liquefaction resistance increased with the increase of relative density.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.6
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• pp.125-134
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• 2010

This study was performed to evaluate the workability, strengths and durability of polymer concrete using oyster shell that are reclaimed at public shore illegally or leaved on the surroundings of shore to prevent the environmental pollution. We investigated the effect of oyster shell powder (OSP) and $CaCO_3$. on the slump, compressive strength, flexural strength, acid sulfuric and freezing and thawing resistance as a filler of polymer concrete. Modified OSP obtained by crushing oyster shell (less than 0.15 mm size) consists of 60.47 wt% of $SiO_2$ and 39.5 wt% of $CaCO_3$. As a result of slump test by OSP and $CaCO_3$. contents, it is found that slump of specimen used OSP is lower than that used $CaCO_3$. and the more OSP contents are, its slump is increased. Compressive and flexural strength of polymer concrete using OSP are similar or slightly lower than that using $CaCO_3$. In acid sulfuric test for 5 % $H_2SO_4$ and freezing thawing test, regardless of kinds of fillers and contents are not found fatal defects in weight change, falling-off in surface and durability factor.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.1
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• pp.10-14
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• 2000

In order to investigate the appropriate processing season and the production of high value-added products in ark shell(Scapharca subcrenata) cultured at the south coast of Korea, the foot muscle, mantle, and adductor muscle were analyzed for moisture, protein, fat, ash, and glycogen using specimens collected bimonthly from December 1994 to December 1995. The contents of moisture in foot muscle and mantle increased in spring season, however their proteins decreased in same season. Glycogen and fat in foot muscle, mantle, and adductor muscle were most abundant in June, just before the spawning season, but all the cmponsnts dwindled during spawning season. The other hand, the contents of ash in tissues were almost the same level through the year. Thus, the contents of moisture, protein, fat, and glycogen were almost the same level through the year. Thus, the contents of moisture, protein, aft, and glycogen were fluctuated by season. Especially, they showed a marked seasonal variation at before and after sparning season. So, a major cause of seasonal variation in S. subcrenata would be connected with a period of reproduction and spawning season.

• Journal of the Korean Home Economics Association
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• v.25 no.4
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• pp.47-55
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• 1987

This study was designed to elucidate the lipid contents, neutral lipids components and fatty acid composition in fresh shellfishes, produced in Korea. Four kinds of shellfishes including sea mussel, short-necked clam, corb shell and and ark shell were selected according to the higher sales order and cheaper retail price at fish markets in Seoul in July 1985. The results abtained were as follows; 1. The average total lipid contents in four shellfishes were 2.3% by wet weight basis. The ratios of neutrial lipid, glycolipid and phospholipid in the total lipid were 51.1 : 4.9 : 44.0 in sea mussel, 66.0 : 3.2 : 30.8 in ark shell, 37.8 : 2.2 : 60.0 in short-necked clam and 54.5 : 2.0 : 53.5 in corb shell, 2. The average value of acid value, iodine value and unsaponifiables contents of total lipids were 1.3, 217.8, 92.0 and 20.3%, respectively. 3. The composition of the neutral lipids were triglycerides, esterified fatty acids, sterylesters, free sterols and monoglycerides in four shellfishes. 4. The major fatty acid composition of total lipids were palmitic, eicosapentaenoic, docosahexaenoic and palmitoleic acids in four shellfishes. The average total unsaturated fatty acids of total lipid were 64.5%, and $\omega$-3 highly unsaturated fatty acids were 27.0%. The average p/s Ratiio were 1.3.

• Journal of the Korea Furniture Society
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• v.24 no.4
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• pp.379-388
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• 2013

In this study, the effect of various glass fiber (GF) contents in a shell layer and shell thickness changes on the flexural property of coextruded wood plastic composites (WPCs) in combination with three core systems (weak, moderate, and strong) was investigated. GF behaved as an effective reinforcement for the whole coextruded WPCs and GF alignments in the shell layer played an important role in determining the flexural property of the coextruded WPCs. At a given shell thickness, the flexural property of the whole coextruded WPCs was improved with the increase of GF content in shell. For core quality, when the core is weak, increase of GF content in shell led to improved flexural property of the whole composites and increase of shell thickness helped it. On the other hand, when the core is strong, the flexural property of the whole composites showed reduced features at low GF content in shell and increase of shell thickness aggravated it. This approach provides a method for optimizing performance of the coextruded WPCs with various combinations of core-shell structure and properties.

• The Korean Journal of Food And Nutrition
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• v.25 no.2
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• pp.224-232
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• 2012

This study was conducted to investigate the effect of chestnut inner shell powder on antioxidant activity and the quality characteristics of cookies. Cookies were prepared with different amounts of chestnut inner shell powder(in ratios of 0, 0.5, 1, 3 and 5% to the flour quantity). The antioxidant activity was estimated by DPPH free radical scavenging activity and the total phenol content in chestnut inner shell powder and cookies. For analyzing quality characteristics, bulk density and pH of the dough, spread factor, loss rate, leavening rate, color, texture profile analysis, and sensory evaluations were measured. The spread ratio, a values, total phenol contents and DPPH free radical scavenging activity of cookies significantly increased with increasing chestnut inner shell powder(p<0.001), while the pH of the dough, L values and b values of the cookies significantly decreased with increasing chestnut inner shell powder content(p<0.001). The consumer acceptability score for the 3% chestnut inner shell cookie groups ranked significantly higher(p<0.01) than those of the other groups in overall preference, flavor, taste and color. From these results, we suggest that chestnut inner shell is a good ingredient for increasing the consumer acceptability and the functionality of cookies.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.5
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• pp.281-286
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• 2005

The effect of oyster shell meal, which is made of a simple crushing and alkaline calcium materials, on soil microbial properties, microbial biomass C, N and P contents, and enzyme activities were evaluated in silt loam soil. The oyster shell meal fertilizer was added at the rates of 0, 4, 8, 12 and $16Mg\;ha^{-1}$. Microbial biomass C, N and P contents were significantly increased with increasing application of oyster shell meal. Soil enzyme activities, such as urease, ${\beta}$-glucosidase and alkaline phosphomonesterase were increased significantly by shell meal application, due to increased soil pH towards neutral range and increased nutrient availability in soil. In particular, the increased microbial biomass P content and phosphomonoesterase activities were strongly correlated with available P content in soil. Conclusively, oyster shell meal fertilizer could be a good supplement to improve soil microbial activities.