• Title/Summary/Keyword: Flow defect

Search Result 347, Processing Time 0.027 seconds

Ultrasonographic Evaluation of the Bone Beating of the Experimentally Induced Bone Defect in Dogs (개에서 실험적 골결손 치유 반응에 대한 초음파 평가)

  • Park, Jin-Hee;Seong, Yun-Sang;Eom, Ki-Dong
    • Journal of Veterinary Clinics
    • /
    • v.23 no.3
    • /
    • pp.258-262
    • /
    • 2006
  • This study was performed to evaluate the usefulness of gray-scale and power Doppler ultrasonography, and to compare with radiography for detection of the repairing in experimentally induced bone defects in dogs. In 4 adult beagle dogs bilateral bone defects were created in 8 canine femurs as sized as 5 mm diameter. Mean detection time of the ultrasonographic endosteal callus formations(mean $14.25{\pm}2.31$ days) was significantly shorter than that of the radiographic opacity chanees(mean $23.50{\pm}2.27$ days) in the defected region. Mean time of the neovascularizd flow signal(mean $6.00{\pm}3.59$ days) from the power Doppler ultrasonographic examination was significantly shorter than that of gray-scale ultrasonographic findings. With these results, gray-scale ultransonography and power Doppler ultrasonography can be used for an early detection modality for bone healing.

A study on mathematical modeling and heat transfer analysis to predict weld bead geometry in horizontal fillet welding (수평필릿용접의 용접부 형상을 예측하기 위한 수학적 모델링 및 열전달 해석에 관한 연구)

  • 문형순;나석주
    • Journal of Welding and Joining
    • /
    • v.14 no.6
    • /
    • pp.58-67
    • /
    • 1996
  • The horizontal filet welding is prevalently used in heavy and ship building industries to join the parts. The phenomena occurring in the horizonal fillet welding process are very complex and highly non-linear, so that its analysis is relatively difficult. Furthermore, various kinds of weld defect such as undercut, overlap, porosity. excess weld metal and incomplete penetration can be induced due to improper welding conditions. Among these defects, undercut, overlap and excess weld metal appear frequently in horizontal filet welding. To achieve a satisfactory weld bead geometry without weld defects, it is necessary to study the effect of welding conditions in the weld bead geometry. For analyzing the weld bead geometry with and without weld defects in horizontal fillet welding, a mathematical model was proposed in conjunction with a two-dimensional heat flow analysis adopted for computing the melting tone in . base metal. The reliability of the proposed model was evaluated through experiments. which showed that the proposed model was very effective for predicting the weld bead shape with or without weld defects in horizontal fillet welding.

  • PDF

Study on the simulation of contamination route and estimation of the pollution sources of DNOC using a numerical model (수치모형을 이용한 DNOC의 물질 거동 모의와 오염원 추정 연구)

  • Park, Kyeong-Deok;Kim, Il-Kyu
    • Journal of Korean Society of Water and Wastewater
    • /
    • v.31 no.1
    • /
    • pp.29-37
    • /
    • 2017
  • To estimate pollution sources in the watershed with various industries, the simulation of contamination route and distribution of 2-methyl-4,6-dinitriophenol(DNOC) were performed with a numerical model Hydro Geo Sphere. This study was performed calculations of the load using the measured concentration and simulated flow rate. And, the river was divided by the sampling sites at the mainstream, and the contribution rate at downstream sampling sites was calculated for each section. The results showed the concentration of the downstream sampling sites were decided by the concentration of upstream sites, and the contribution rates of the tributaries were calculated below 10%. The results also showed that the impact of the potential sources in Section 1(Geumho1 ~ Geumho2) and Section 5(Geumho5 ~ Geumho6) was larger than in the other area. In Section1 and Section5, It seemed to require detailed investigation.

Ventricular Septal Defect by Penetrating Chest Trauma - Report of One Case - (관통성 흉부 자상에 의한 심실중격 결손증: 증례보고)

  • Kim, Mun-Hwan;Lee, Cheol-Ju
    • Journal of Chest Surgery
    • /
    • v.25 no.4
    • /
    • pp.429-434
    • /
    • 1992
  • We experienced a rare case of traumatic ventricular septal defect by penetrating stab injury The patient was 26-year-old women who got stab wound at the left anterior third intercostal space and left sternal border with a knife. seven hours after admission, the patient was undertaken an emergency thoracotomy due to hypovolemic shock caused by massive bleeding from transected left internal mammary artery, vein, and right ventricular outflow tract. On postoperative second day, the patient was suffered from moderate dyspnea, and arterial blood gas analysis and chest X-ray revealed hypoxemia and pulmonary edema. Right heart cardiac catheterization with Swan-Ganz Cathater showed oxygen step-up between right atrium and main pulmonary artery and a 1.6:1 ratio of pulmonary to systemic blood flow. At operation, harsh systolic thrill was palpable along right ventricular outflow tract. Through small vertical right ventriculotomy, the linear ventricular septal laceration on infundibular septum was noticed, and its size was 1.5cm with sharp margin This defeat was repaired by three interrupted matress sutures using Prolene 4-O with pledget. Her postoperative course was uneventful, and she discharged with good physical condition.

  • PDF

A Study of the Defect Detection Method of Vision Technology via Camera Image Analysis on 4-col 7-row LED Screen Module (4단 7열 LED 사이니지 전면부 설치형 카메라기반 불량 LED 소자 검출 Vision 기술에 관한 연구)

  • Park, Young ki;Im, Sang il;Jo, Ik hyeon;Cha, Jae sang
    • Journal of Korea Multimedia Society
    • /
    • v.23 no.11
    • /
    • pp.1383-1387
    • /
    • 2020
  • Recently, a 4-col 7-row LED Screen that provides various information of major roads and local governments has been installed and operated. However, due to deterioration due to changes in temperature and humidity, deterioration due to static electricity, and mechanical stress, partial module failure of the display may occur, which is a major cause of missing information of vitally given to citizens. However, there have been frequent cases where the 4-col and 7-row LED Screen that have failed due to reasons such as installed location where the signboards are installed on the road and outdoor, the lack of monitoring means at all times, and the lack of manpower is often neglected for a long time. Following this flow, this paper proposes a method to detect defective modules by analyzing the images collected through the camera fixed to the front part of the LED display.

Thermal Performance Evaluation of Apartment Housing Using Infra-red Camera (적외선 열화상을 이용한 공동주택 단열성능 평가 : TDR(온도차비율)을 중심으로)

  • Choi, Gyeong-Seok;Sohn, Jang-Yeul
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.22 no.6
    • /
    • pp.404-412
    • /
    • 2010
  • The purpose of this study is to accomplished an in-site evaluation method for existing building insulation status using Infra-red camera and to consider improvement performance to prevent condensation and draw the optimum insulation design method for building using simulation tool. The research contents of this study are to evaluate validity and suitability of building insulation defect survey using Infra-red camera for apartment housing with temperature and heat flow pattern analyze method. Based on this research, the three corners, weak part in condensation, were selected in apartment building and conducted simulation by three-dimensional steady state. From the results, it is required to strengthen insulation design, and it is founded that existing insulation system typically applied to most Korean apartment housings have serious insulation defect that insulation is disconnected by structural components at the joints of wall-slab and wall-wall in envelope. Thus, it is considerate to need a concrete technology improvement.

Analysis of Weld Beads for Wall Thinning Defects in the Weld Zone of the Boost Pump Recirculation Pipe for Power Plants and Evaluation of Their Integrity (플랜트 승압펌프 재순환 배관 용접부의 용접비드에 의해 발생한 감육결함 분석 및 건전성 평가)

  • Nam, Ki-Woo;Ahn, Seok-Hwan;Do, Jae-Yoon
    • Journal of Ocean Engineering and Technology
    • /
    • v.24 no.4
    • /
    • pp.38-46
    • /
    • 2010
  • The wall thinning phenomenon of pipes was simulated as metal loss due to erosion and corrosion. Such wall thinning defects in the pipes of power plants are a very important safety consideration. In this study, we analyzed wall thinning defects that occurred by weld bead of weld zone of boost pump recirculation pipe. From the results of the analysis of pipe failures, numerical analysis was performed by Fluent v6.3.26 using the standard k-$\varepsilon$ model of the weld bead shape, such as an elliptical or a spherical shape, on the inner wall of the pipe. Using the results obtained, we showed the overlap effect by cavitations corrosion and erosion-corrosion at the bottom of the wall-thinning defect.

A Study of End Point Detection Measurement for STI-CMP Applications (STI-CMP 공정 적용을 위한 연마 정지점 고찰)

  • 김상용;서용진
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.14 no.3
    • /
    • pp.175-184
    • /
    • 2001
  • In this study, the improved throughput and stability in device fabrication could be obtained by applying CMP process to STi structue in 0.18 um semiconductor device. To employ the CMP process in STI structure, the Reverse Moat Process used to be added after STI Fill, as a result, the process became more complex and the defect were seriously increased than they had been,. Removal rate of each thin film in STI CMP was not uniform, so, the device must have been affected. That is, in case of excessive CMP, the damage on the active area was occurred, and in the case of insufficient CMP nitride remaining was happened on that area. Both of them deteriorated device characteristics. As a solution to these problems, the development of slurry having high removal rate and high oxide to nitride selectivity has been studied. The process using this slurry afford low defect levels, improved yield, and a simplified process flow. In this study, we evaluated the 'High Selectivity Slurry' to do a global planarization without reverse moat step, and also we evaluated EPD(Eend Point Detection) system with which 'in-situ end point detection' is possible.

  • PDF

Low Cycle Fatigue Behaviour of AISI 304L Austenitic Stainless Steel Weldment (AISI 304L 오오스테나이트 스테인레스 강 용접부 의 Low Cycle Fatigue 거동에 관한 연구)

  • 김환태;황선효;남수우
    • Journal of Welding and Joining
    • /
    • v.2 no.1
    • /
    • pp.49-57
    • /
    • 1984
  • The influence of weld defect, residual stress and microstructure on the Low Cycle Fatigue(L. C. F.) behaviour of AISI 304L austenitic stainless steel weldment has been studied. The specimens were welded by shielded metal are welding process, post weld heat treated(PWHT) at 900.deg.C for 1.5hrs, and tested under total strain controlled condition at room temperature. The results of the experiment showed that weld defect affected the L.C.F. behaviour of weldment deleteriously compared to the residual stress or microstructure, and it reduced the L.C.F. life about 70-80%. The PWHT exhibited beneficial effect on the L.C.F. behaviour and increased the L.C.F. life about 120%. This enhancement by PWHT was attributed to the removal of residual stress and recovery of weld metal ductility. The cyclic stress flow of as welded specimens showed intermediate cyclic softening, whereas those of heat treated specimens showed continuous cyclic hardening, and this difference was explained in terms of the residual stress removal and dislocation behaviour. Scanning electron microscopy studies of fatigue fracture surface showed that weld defects of large size and near weld surface were detrimental to the L.C.F. behaviour of weldment.

  • PDF

A Case Report of Restrictive Ventricular Septal Defect & Left Ventricular Out Flow Tract Stenosis Caused by Fibrotic Tissue in Tetralogy of Fallot (섬유성 조직으로 인한 제한적 심실 중격 결손과 좌심실 유출로 협착을 보인 활로씨 4증 1예 보고)

  • Hwang, Ui-Dong;Jung, Sung-Ho;Seo, Dong-Man
    • Journal of Chest Surgery
    • /
    • v.39 no.11 s.268
    • /
    • pp.850-853
    • /
    • 2006
  • The VSD in TOF is usually large and unrestrictive with an equal to or greater than that of the aortic annulus. Typically shunting through the VSD is bidirectional or right-to-left component. Restrictive VSD in TOF caused by ingrowing fibrotic tissue is very rare. We report a case of restrictive VSD and LVOTO in TOF caused by ingrowing fibrotic tissue with the review of literature.