• Title/Summary/Keyword: cdf

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Flow Safety Assessment by CFD Analysis in One-Touch Insertion Type Pipe Joint for Refrigerant (CFD 해석을 이용한 냉매용 원터치 삽입식 파이프 조인트의 유동 안전성 평가)

  • Kim, Eun-young;Park, Dong-sam
    • Journal of the Society of Disaster Information
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    • v.18 no.3
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    • pp.550-559
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    • 2022
  • Purpose: Pipes are widely used as applied devices in many industrial fields such as machinery, electronics, electricity, and plants, and are also widely used in safety-related fields such as firefighting and chemistry. With the diversification of products, the importance of technology in the piping field is also increasing. In particular, when changing the existing copper pipe to stainless steel, it is necessary to evaluate safety and flow characteristics through structural analysis or flow analysis. Method: This study investigated the safety by flow analysis of the 6.35 inch socket model, which are integrated insert type connectors developed by a company, using CFD analysis technique. For CDF analysis, RAN model and LES model are used. Result: As results of the analysis, amplitude of the pressure fluctuation acting on the wall of the piping system is formed at a level of 3,780 Pa or less, which is a very small level of pressure compared with the operating pressure or design stress of the refrigerant piping. Conclusion: These results mean that the effect of vibration caused by turbulence on the structural safety of the pipe is negligible.

Treatment and Survial Rate of Malignant Peripheral Nerve Sheath Tumors (악성 말초신경막 종양의 치료와 생존율)

  • Lee, Jong-Seok;Jeon, Dae-Geun;Cho, Wan-Hyung;Lee, Soo-Yong;Oh, Jung-Moon;Kim, Jin-Wook
    • The Journal of the Korean bone and joint tumor society
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    • v.9 no.2
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    • pp.131-138
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    • 2003
  • Purpose: We analyzed our malignant peripheral nerve sheath tumor (MPNST) cases to find out their oncologic results following by each treatment modalities. Materials and Methods: Thirty four patients with MPNST were registered in Korea Cancer Center Hospital from Feb. 1986 to Nov. 1996. Seventeen cases were male and 17, female. Average age was 41 years (range 18 to 74). Location of the tumor was as follows; 17 in lower extremity, 11 upper extremity, 4 trunk, and 2 retroperitoneum. Following the AJC classification, stage IA were 2 cases, stage IIA 2, stage IIB 6, stage III 16 and stage IV 8. Twenty six patients took operations and adjuvant chemotherapy and/or radiation therapy, 3 operation only and 3 adjuvant chemotherapy or radiation therapy. Average follow up period was 33.5 months (5.6 to 146.1). Kaplan-Meiyer method was done for survival curve, and log rank test for comparison analysis. Results: Fourteen cases were continuous disease free, 2 no evidence of disease, 2 alive with disease and 14 dead of disease states at final follow up. Actual 5-year and 10-year survival rates were 53.5%, 35.7%. Local recurrence rate after operation was 24.1%. 5-year survival rates of stage I/II/III were 100/85.7/55.9% and 2-year survival rate of stage IV was 14.3% (p=0.04). In 21 cases operated with stage II-III, wide margin (15cases) had 76.0% 5-year survival rate, and marginal or intralesional marigin (6cases) had 40.0%. The actual 5-year survival rate of the group which were done 4 or more cycles chemotherapy (8cases) was 71.4% and the actual 3-year survival rate less than 4cycles chemotherapy (6cases) was 83.3% (p=0.96). In 19 cases operated with stage II-III and which had no radiotherapy, marginal or intralesional margin (5cases) had 3 cases of local recurrences (60.0%), though wide margin (14cases) had 4 cases recurrences (28.6%). There was no local recurrence in 8cases which had pre-or post-operative radiotherapy. Conclusions: Surgical margin is an important factor in local recurrence. Resection margin has a tendency to influence the survival despite insufficient statistical significance. Conventional chemotherapy has no defnite statistical sigficance in the effect on local control and survival. Preoperative and postoperative radiotherapy has some positive effect on local control.

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Functional Outcomes of Internal Pelvectomy without Reconstruction for Periacetabular Maligmant Tumors (비구주변 골반골 악성 골종양에서 재건술을 시행하지 않은 내골반골 절제술의 기능적 결과)

  • Chung, Yang-Guk;Kang, Yong-Koo;Lee, Seung-Koo;Bahk, Won-Jong;Lee, An-Hi;Park, Jung-Mi;Lee, Kyo-Sun;Lee, Hyung-Ju
    • The Journal of the Korean bone and joint tumor society
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    • v.13 no.1
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    • pp.60-66
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    • 2007
  • Purpose: The purpose of this study was to evaluate the functional outcomes of periacetabular malignant bone tumors treated by internal pelvectomy without reconstruction. Materials and methods: Between January 1996 and December 2005, eight patients with primary malignant or metastatic periacetabular bone tumors were treated by internal pelvectomy without reconstruction. There were 6 men and 2 women. Mean age was 42 years old. There were 3 osteosarcomas, 3 chondrosarcomas and 2 metastatic carcinomas. The type of pelvic resections were 6 type I+II+III, 1 type I+II and 1 type II+II resection. The functional outcomes were evaluated with ISOLS revised criteria. The follow up period ranged from 6 to 84 months. Results: At last follow up, 5 patients showed CDF, 2 patients, AWD and the remained 1, DOD. The mean functional score for pain, functional activity, emotional acceptance, use of external support, walking ability and gait were 4.9, 2.9, 2.9, 1.5, 2.3 and 2.5 respectively. The total functional score ranged from 37% to 70%(average: 56%). There were three temporary nerve palsies. Conclusion: The internal pelvectomy without reconstruction for selective difficult periacetabular malignant tumors could be a viable option with fewer complications and fair functional outcomes.

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The KMA Global Seasonal forecasting system (GloSea6) - Part 2: Climatological Mean Bias Characteristics (기상청 기후예측시스템(GloSea6) - Part 2: 기후모의 평균 오차 특성 분석)

  • Hyun, Yu-Kyung;Lee, Johan;Shin, Beomcheol;Choi, Yuna;Kim, Ji-Yeong;Lee, Sang-Min;Ji, Hee-Sook;Boo, Kyung-On;Lim, Somin;Kim, Hyeri;Ryu, Young;Park, Yeon-Hee;Park, Hyeong-Sik;Choo, Sung-Ho;Hyun, Seung-Hwon;Hwang, Seung-On
    • Atmosphere
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    • v.32 no.2
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    • pp.87-101
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    • 2022
  • In this paper, the performance improvement for the new KMA's Climate Prediction System (GloSea6), which has been built and tested in 2021, is presented by assessing the bias distribution of basic variables from 24 years of GloSea6 hindcasts. Along with the upgrade from GloSea5 to GloSea6, the performance of GloSea6 can be regarded as notable in many respects: improvements in (i) negative bias of geopotential height over the tropical and mid-latitude troposphere and over polar stratosphere in boreal summer; (ii) cold bias of tropospheric temperature; (iii) underestimation of mid-latitude jets; (iv) dry bias in the lower troposphere; (v) cold tongue bias in the equatorial SST and the warm bias of Southern Ocean, suggesting the potential of improvements to the major climate variability in GloSea6. The warm surface temperature in the northern hemisphere continent in summer is eliminated by using CDF-matched soil-moisture initials. However, the cold bias in high latitude snow-covered area in winter still needs to be improved in the future. The intensification of the westerly winds of the summer Asian monsoon and the weakening of the northwest Pacific high, which are considered to be major errors in the GloSea system, had not been significantly improved. However, both the use of increased number of ensembles and the initial conditions at the closest initial dates reveals possibility to improve these biases. It is also noted that the effect of ensemble expansion mainly contributes to the improvement of annual variability over high latitudes and polar regions.