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Development of Lab-Scale Rock Drill Apparatus for Testing Performance of a Drill Bit
Song, Chang-Heon,Kwon, Ki-Beom,Cho, Min-Gi,Oh, Joo-Young,Shin, Dae-Young,Cho, Jung-Woo Korean Society for Precision Engineering 2015 International Journal of Precision Engineering and Vol.16 No.7
This study experimentally validated the reliability of the lab-scale rock drill apparatus and investigated the effect of bit design factors on the performance of drilling. To test drilling efficiency of a drill bit, a testing system was designed and manufactured. Using the testing system, the drilling rates and specific energy of a conventional drill bit and newly proposed drill bit with different button arrangement were compared. The newly proposed model was tested to be superior in drilling performance than that of the conventional model. The testing system developed in this study could be used to predict and test the performance of newly developed drill bit models. Also, the system has to be improved further for measuring more accurate and quantitative data for future drill bit developments.
( Heon-ju Kwon ),( Kyoung Won Kim ),( Bohyun Kim ),( So Yeon Kim ),( Chul Seung Lee ),( Jeongjin Lee ),( Gi Won Song ),( Sung Gyu Lee ) 대한간학회 2018 Clinical and Molecular Hepatology(대한간학회지) Vol.24 No.1
Background/Aims: Computed tomography (CT) hepatic volumetry is currently accepted as the most reliable method for preoperative estimation of graft weight in living donor liver transplantation (LDLT). However, several factors can cause inaccuracies in CT volumetry compared to real graft weight. The purpose of this study was to determine the frequency and degree of resection plane-dependent error in CT volumetry of the right hepatic lobe in LDLT. Methods: Forty-six living liver donors underwent CT before donor surgery and on postoperative day 7. Prospective CT volumetry (V< SUB >P< /SUB >) was measured via the assumptive hepatectomy plane. Retrospective liver volume (V< SUB >R< /SUB >) was measured using the actual plane by comparing preoperative and postoperative CT. Compared with intraoperatively measured weight (W), errors in percentage (%) V< SUB >P< /SUB > and V< SUB >R< /SUB > were evaluated. Plane-dependent error in V< SUB >P< /SUB > was defined as the absolute difference between V< SUB >P< /SUB > and V< SUB >R< /SUB >. % plane-dependent error was defined as follows: |V< SUB >P< /SUB >-V< SUB >R< /SUB >|/W·100. Results: Mean V< SUB >P< /SUB >, V< SUB >R< /SUB >, and W were 761.9 mL, 755.0 mL, and 696.9 g. Mean and % errors in V< SUB >P< /SUB > were 73.3 mL and 10.7%. Mean error and % error in V< SUB >R< /SUB > were 64.4 mL and 9.3%. Mean plane-dependent error in V< SUB >P< /SUB > was 32.4 mL. Mean % planedependent error was 4.7%. Plane-dependent error in V< SUB >P< /SUB > exceeded 10% of W in approximately 10% of the subjects in our study. Conclusions: There was approximately 5% plane-dependent error in liver V< SUB >P< /SUB > on CT volumetry. Plane-dependent error in V< SUB >P< /SUB > exceeded 10% of W in approximately 10% of LDLT donors in our study. This error should be considered, especially when CT volumetry is performed by a less experienced operator who is not well acquainted with the donor hepatectomy plane. (Clin Mol Hepatol 2018;24:54-60)
Resection Plane-Dependent Error of CT Volumetry for Right Hepatic Lobe in Live Liver Donors
( Heon-ju Kwon ),( Kyoung Won Kim ),( Bohyun Kim ),( So Yeon Kim ),( Jeongjin Lee ),( Gi Won Song ),( Sung Gyu Lee ) 대한간학회 2017 춘·추계 학술대회 (KASL) Vol.2017 No.1
Aims: CT hepatic volumetry is currently accepted as the most reliable method for preoperative assumption of the graft weight for living donor liver transplantation. However, the estimated value from CT volumetry can be deviated from real graft weight due to several factors including the difference between the preoperative assumptive and the actual hepatectomy planes. It may be worthwhile to determine how much each factor contributes to the error of CT volumetry. Thus, the purpose of this study was to determine the resection plane-dependent error of CT volumetry for right hepatic lobe in live liver donors. Methods: Forty-six live liver donors underwent CT scans ≤2 months before the liver procurement and within postoperative day 7. CT volumetry was performed by two radiologists in consensus using a computer-aided liver volumetry software. Prospective CT volumetry (VP) was measured with assumptive hepatectomy plane. Retrospective liver volume (VR) was measured using actual plane determined by comparing preoperative and postoperative CT scans. Compared with intraoperatively measured weight (W), errors of percentage (%) VP and VR were evaluated. Plane-dependent error of VP was defined as absolute difference between VP and VR. % plane-dependent error was defined as follow:|VP-VR|/W·100. Results: Mean VP, VR, and W were 761.9 mL, 755.0 mL, and 696.9g. Mean and % errors of VP were 73.3 mL and 10.7%. Mean error and % error of VR were 64.4 mL and 9.3%. Mean plane-dependent error of VP was 32.4 mL. Mean % plane-dependent error was 4.7%. The plane-dependent error of VP exceeded 10% of W in approximately 10% of the subjects in our study. Conclusions: There is approximately 5% plane-dependent error for VP at CT volumetry. However, even with correction of plane-dependent error, error of VR is still approximately 9% compared with W.
Computational Fluid Dynamics Simulation of Coal Ash Filling in Underground Mine Cavity
Song, Chang-Heon,Cho, Min-Gi,Park, Jin-Young,Lee, Jae-Wook,Cho, Jung-Woo,Jang, Hang-Seok,Lee, Sang-Eun,Chung, Jintai Korean Society for Precision Engineering 2015 International Journal of Precision Engineering and Vol.16 No.7
Coal fly ash waste from thermal power plants has recently been considered as a fill material for abandoned coal mine voids in Korea. A volume of fluid method, used in computational fluid dynamics, was adopted to simulate the process of coal ash injection into mine cavities. The difference in the filling efficiency of coal ash versus water using both upper and lower injection points was also investigated. Results show that use of a lower injection point more stably packed the cavity and provided a higher density of fill than use of an upper injection point. Thus, it would be better to place the nozzle of the injection pipe near the bottom of the mine cavity, below the groundwater level.
The Beneficial Effects of Nardostachys jatamansi Extract on Diet-Induced Severe Acute Pancreatitis
Bae, Gi-Sang,Park, Kyoung-Chel,Koo, Bon Soon,Jo, Il-Joo,Choi, Sun Bok,Lee, Dong-Sung,Kim, Youn-Chul,Kim, Jong-Jin,Shin, Yong Kook,Hong, Seung-Heon,Kim, Tae-Hyeon,Song, Ho-Joon,Park, Sung-Joo Lippincott Williams Wilkins, Inc. 2013 Pancreas Vol.42 No.2