• Food Science of Animal Resources
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• v.28 no.5
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• pp.610-615
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• 2008

This experiment was conducted to investigate the effects of drinking of Rhus tree-extract on laying performance and egg quality in hens. Four hundred eighty, 55-wk-old ISA brown, laying hens were divided into six groups, control, Rhus tree-extract 500 ppm, 1,000 ppm, 2,000 ppm, 3,000 ppm and 5,000 ppm. The hens were fed a supplemented drink containing Rhus tree-extract for 12 weeks. Egg production and egg mass increased by drinking Rhus tree-extract (p<0.05) and the feed conversion ratio also improved in Rhus tree-extract groups. Cecal numbers of Lactobacillus spp., E. coli and Salmonella were not different in treatments. Availability of protein and ash improved in the Rhus extract groups. The eggshell breaking strength and egg shell thickness were significantly increased in Rhus tree-extract 3,000 ppm and Rhus tree-extract 2,000 ppm groups compared to the other groups. Also, egg yolk color and Haugh unit were significantly improved by the dietary Rhus tree-extract (p<0.05).

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.387-393
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• 2021

In this study, finite element analysis was performed to evaluate a method of increasing the fatigue life of the pipe connection structure commonly used in the topside structure of offshore platforms. MSC Patran/Nastran, a commercial analysis program, was used, and the critical structural model was selected from the global analysis. To realize the stress concentration phenomenon according to the load, modeling using 8-node solid elements was implemented. The main loads were considered to be two lateral loads and a tensile load on a diagonal pipe. To check the hotspot stress at the main location, a 0.01 mm dummy shell element was applied. After calculating the main stress at the 0.5-t and 1.5-t locations, the stress generated in the weld was estimated through extrapolation. In some sections, this stress was observed to be below the fatigue life that should be satisfied, and reinforcement was required. For reinforcement, a bracket was added to reduce the stress concentration factor where the fatigue life was insufficient without changing the thickness or diameter of the previously designed pipe. Regarding the tensile load, the stress in the bracket toe increased by 23 %, whereas the stress inside and outside of the pipe, which was a problem, decreased by approximately 8 %. Regarding the flexural load, the stress at the bracket toe increased by 3 %, whereas the stress inside and outside of the pipe, which was also a problem, decreased by approximately 48 %. Owing to the new bracket reinforcement, the stress in the bracket toe increased, but the S-N curve itself was better than that of the pipe joint, so it was not a significant problem. The improvement method of fatigue life is expected to be useful; it can efficiently increase the fatigue life while minimizing changes to the initial design.