유용미생물(EM)을 이용한 토양 중 TPH 저감 방법에 관한 연구

장윤영,안종현,김임순 한국방재학회 2014 한국방재학회 학술발표대회논문집 Vol.2014 No.-

본 연구에서는 생물학적 정화기술의 효율향상을 목적으로 유류분해 유용미생물에 의한 TPH 농도 저감효과를 알아보았다. 하절기와 동절기 각 13주간 실제 정화현장의 각 섹터별 유류오염토양에 유용미생물들을 수분, 영양염류 등과 함께 투입하여 주 2회 정기적으로 뒤집기를 실시하였다. 하절기의 경우 유용미생물을 투입한 조건의 경우 평균 60%의 TPH 제거율을 보인 반면에 유용미생물을 투입하지 않은 대조군의 경우 평균 41%의 TPH 제거율을 나타내었다. 동절기의 경우에 유용미생물을 투입한 조건의 경우 평균 41%의 TPH 제거율을 보인 반면에 유용미생물을 투입하지 않은 대조군의 경우 평균 13%의 낮은 TPH 제거율을 나타내었다.결론적으로 하절기와 동절기 모두 유용미생물을 투입하여 TPH의 제거효율의 향상 효과를 얻을 수 있었으며, 하절기에 비하여 동절기의 TPH 제거효과가 낮은 이유는 초기 높은 오염농도와 상대적으로 낮은 기온의 영향인 것으로 판단된다.

Prediction of fracture parameters of circumferential through-wall cracks in the interface between an elbow and a pipe under internal pressure

장윤영,Jae-Uk Jeong,NAM-SU HUH 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.9

This paper provides plastic influence functions of GE/EPRI method for calculating J and Crack opening displacement (COD) of pipes with a circumferential Through-wall crack (TWC) in the interface between an elbow and a straight pipe by using 3-dimensional (3-D) elastic-plastic finite element analyses for Ramberg-Osgood (R-O) materials, in which internal pressure was considered as a loading condition. The proposed plastic influence functions are tabulated as a function of the pipe geometries, crack length and strain hardening exponent. In order to provide sufficient confidence for the proposed plastic influence functions, the estimation scheme using the proposed plastic influence functions for J and COD of cracked elbows was validated against FE results using R-O parameters for the SA312 TP316 stainless steel. Moreover, the predicted J and COD for elbows with a TWC in the interface between an elbow and a pipe by the proposed scheme were compared with those for cracked straight pipes to investigate the effect of the elbow geometries on crack behavior of elbows. One important point is that crack behaviors in the interface between an elbow and a straight pipe can be significantly different with those in straight pipes according to pipe thickness, crack length and bend radius of elbows. Thus, the proposed plastic influence functions can be useful to predict accurate J and COD for cracked elbows.

점액저류낭을 가진 상악동에서 상악동 골이식술을 동반한 임플란트 수복의 증례보고

장윤영,윤정호 대한치과의사협회 2022 대한치과의사협회지 Vol.60 No.4

Various risk factors should be thoroughly evaluated for successful sinus floor augmentation and implant placement. Among them, mucous retention cyst could be commonly found on radiographic evaluation. The aim of this study was to demonstrate sinus floor augmentation using lateral approach and implant placement on maxillary sinus in the presence of mucous retention cyst. Two cases which require sinus floor augmentation and implant placement on maxillary posterior edentulous area were involved in this report. Well-defined radiopaque mucous retention cysts without specific sign and symptom were observed in radiographic evaluation. In one case, sinus floor augmentation was performed simultaneously with implant placement, and seromucous fluid within mucous retention cyst was aspirated with syringe needle during the surgery. In the other case, sinus floor augmentation and implant placement were conducted in two-stage approach, and aspiration was also performed in mucous retention cyst to extract fluid during the sinus floor augmentation. Prosthesis was successfully installed on implants, and no clinical complications were observed on periodic check-up. It could be concluded that sinus floor augmentation and implant placement on maxillary sinus with mucous retention cyst could be successfully performed.

Crack-tip constraints of through-wall cracked pipes and its similarity to curved wide plates

장윤영,Jae-Uk Jeong,허남수,Ki-Seok Kim,Woo-Yeon Cho 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.10

In the present study, the effects of pipe geometries, material properties and loading conditions on crack-tip constraints of pipes with circumferential Through-wall crack (TWC) were investigated via systematic 3-dimensional (3-D) Finite element (FE) analyses. The crack-tip constraints were quantified by Q-stress, and to characterize the elastic-plastic strain hardening material behavior, RambergOsgood (R-O) material was employed. Based on the FE results, it was observed that crack-tip constraints of pipes with TWC were dependent on crack length and thickness of pipe, however, the effects of each variables decreased as either thickness of pipe becomes thinner or crack length becomes longer. Moreover, the effects loading modes on Q-stresses for thin-walled pipes with TWC are negligible. Finally, the present Q-stresses of pipes were compared with those of Curved wide plate (CWP) in tension to address the similarity of crack-tip constraints between pipe and CWP, which could be used to produce the CWP to measure the fracture toughness of pipes accurately.

GaAs MESFET의 파괴특성 향상을 위한 recess게이트 구조

장윤영,송정근 한국전기전자재료학회 1994 電氣電子材料學會誌 Vol.7 No.5

In this study we developed a program(DEVSIM) to simulate the two dimensional distribution of the electrostatic potential and the electric field of the arbitrary structure consisting of GaAs/AlGaAs semiconductor and metal as well as dielectric. By the comparision of the electric field distribution of GaAs MESFETs with the various recess gates we proposed a suitable device structure to improve the breakdown characteristics of MESFET. According to the results of simulation the breakdown characteristics were improved as the thickness of the active epitaxial layer was decreased. And the planar structure, which had the highly doped layer under the drain for the ohmic contact, was the worst because the highly doped layer prevented the space charge layer below the gate from extending to the drain, which produced the narrow spaced distribution of the electrostatic potential contours resulting in the high electric field near the drain end. Instead of the planar structure with the highly doped drain the recess gate structure having the highly doped epitaxial drain layer show the better breakdown characteristics by allowing the extention of the space charge layer to the drain. Especially, the structure in which the part of the drain epitaxial layer near the gate show the more improvement of the breakdown characteristics.

유류오염토양으로부터 발생하는 VOC가스처리를 위한 바이오스크러버 개발

장윤영,황경엽,곽재호,최대기 한국지하수토양환경학회 1997 지하수토양환경 Vol.2 No.1

Aiming at the treatment of large volumes of gas with a low concentration of poorly water soluble VOC(Volatile Organic Compound), a new system is proposed: the combination absorption tower/bioreactor. In the scrubber part of the bioscrubbing system, the contaminating compounds are absorbed in a aqueous phase. The contaminated scrubbing liquid is transported to the bioreactor, where the compounds are biodegraded by aerobic microorganisms (mainly to carbon dioxide, water, and biomass). In this study, separation of a volatile organic compound(VOC) out of a waste gas stream has been carried out using a re-cyclable high boiling point extrant(HBE). The liquid stream containing a high boiling point entrant(HBE) scrubs the gas stream in a direct gas-liquid countercurrent contacting operation in a packed tower for the removal of said component from the gaseous stream. A packed-bed column using Pall Ring was set up in order to simulate practical conditions for the scrubbing tower. The liquid stream transported to the bioreactor is recovered and recycled to the scrubber. The model gas, which contained 400 mg/$\textrm{m}^3$ of toluene, at a rate of 100 L/min, flowed into the packed column where the scrubbing liquid trickled over the packing in countercurrent to the rising gas at 10~15L/min. The bioscrubber designed for large volume air streams containing VOCs showed removal efficiency up to 80% in an optimum operating conditions during the tests fer removing toluene from an air stream by scrubbing the air stream with HBE. 저농도의 난 수용성 VOC가스가 포함되어 있는 다량의 오염가스를 처리하기 위하여 흡수탑과 생물반응기의 결합체인 새로운 처리시스템을 제시하였다. 바이오스크러버의 스크러버에서는 세정액으로 기상중의 처리대상오염물질의 흡수가 일어나며 세정액은 생물반응기로 이송되어 호기성 미생물이 오염물을 분해시킨다. 본 연구에서는 폐가스중의 VOC분리를 위하여 재순환가능한 고비점용매를 사용하였다. 고비점용매를 포함한 세정액은 기/액 향류접촉이 이루어지는 흡수탑의 충전층에서 폐가스중의 오염물을 분리한다. 흡수탑은 Pall ring충전제로 채워 실제공정을 모사 하고자 하였다. 흡수처리후 생물반응기로 이송된 흡수액은 재생 후 다시 흡수탑으로 재 순환하였다. 실험에 사용된 대상가스는 농도가 400 mg/$\textrm{m}^3$ 인 톨루엔으로, 세정액이 가스흐름과 향류로 약 10~15L/min의 유량으로 충전층을 적시며 내려오는 충전탑내부로 약 100 L/min의 유량으로 도입하였다. VOC처리를 위해 제작된 본 바이오스크러버에서 고비점용매를 이용한 연속실험결과 최적운전 조건에서 약 80%의 처리율을 얻을 수 있었다.

강경애의「 어머니와 딸 」연구

장윤영 상명대학교 대학원 1995 祥明論集 Vol.2 No.1

해안지역 유류저장시설에서의 오염확산 예측 모델링

장윤영,박선환 한국EHS평가학회 2006 한국EHS평가학회지 Vol.4 No.1

Comparative preclinical assessment of the use of dehydrated human amnion/chorion membrane to repair perforated sinus membranes

장윤영,김수환,고미선,윤정호 대한치주과학회 2019 Journal of Periodontal & Implant Science Vol.49 No.5

Purpose: The aim of this study was to evaluate the use of dehydrated human amnion/chorion membrane (dHACM) to repair perforated sinus membranes in rabbits. Methods: Bilateral surgical windows (7.5-mm diameter) were prepared on the nasal bones of 14 rabbits. Standardized circular perforations (5-mm diameter) were made in the sinus membrane by manipulating implant twist drills. The perforated sinus membranes were repaired using dHACM or a resorbable collagen membrane (CM). The negative control (NC) group did not undergo perforated sinus membrane repair, while the positive control (PC) group underwent sinus augmentation without perforations. The same amount of deproteinized porcine bone mineral was grafted in all 4 groups. After 6 weeks, micro-computed tomography (micro-CT) and histomorphometric evaluations were conducted. Results: The micro-CT analysis revealed that the total augmented volume was not significantly different among the groups. In the dHACM group, newly formed bone filled the augmented area with remaining biomaterials; however, non-ciliated flat epithelium and inflammatory cells were observed on the healed sinus membrane. Histometric analysis showed that the percentage of newly formed bone area in the dHACM group did not differ significantly from that in the CM group. The dHACM group showed a significantly higher percentage of newly formed bone area than the NC group, but there was no significant difference between the dHACM and PC groups. Conclusions: dHACM could be a feasible solution for repairing sinus membrane perforations that occur during sinus floor augmentation.

Numerical investigation of the transferability of ductile fracture behavior between thin-walled surface-cracked pipe, curved wide plate (CWP) and single edge notched tension (SENT) specimens

장윤영,김익중,허남수,김기석,김영표 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.9

Curved wide plate (CWP) and single edge notched tension (SENT) tests are commonly considered for determining the fracture toughnesses of high-strength line-pipe steel for the strain-based design. However, the tearing resistance relationship between these tests and actual thin-walled surface-cracked pipe has not been clearly established. The purpose of this study is to compare the crack growth characteristics of actual pipe, CWP and SENT using the local damage method, which is based on the Gurson-Tvergaard-Needleman (GTN) model. Small-scale testing of smooth round bar tensile and SENT specimens provides the information required to calibrate the damage parameters of the GTN model. Crack growth simulations are then conducted using the calibrated GTN model to evaluate the tearing resistance behaviors of various geometries. The tearing resistances of the CWP and the actual pipe are similar, whereas the SENT specimen exhibits a higher stress triaxiality. However, this tendency of SENT specimen changes as the crack propagates, which is related to the conservatism of the crack growth resistance curve. Therefore, it is necessary to identify the SENT test specimen usability and limitation via ductile damage simulations.