• 제목/요약/키워드: long-term bed chan

검색결과 10건 처리시간 0.026초

형산강 수계 최적 유사량 공식 선정을 위한 연구 (A Study on the Optimal Sediment Discharge Formula for Hyeongsan River)

  • 안정민;류시완;이남주
    • 한국수자원학회논문집
    • /
    • 제43권11호
    • /
    • pp.977-984
    • /
    • 2010
  • 본 연구에서는 실측 유량-유사량, 하상재료, 하천측량자료들을 바탕으로 HEC-6모형을 이용한 형산강의 장기하상변동 모의결과들의 비교를 통하여 형산강유역에 적합한 최적유사량공식을 선정하고자 하였다. 이를 위하여 다양한 통계적 특성치들을 기준으로 Ackers와 White (1973), Duboys (1879), Laursen (1958), Laursen (modified by Madden, 1993), Laursen (modified by Copeland, 1989), 그리고 Yang (1973) 공식과 같은 유사량공식들을 비교 검토하였다. 각 유사량공식을 이용한 장기하상변동 모의결과의 실측치에 대한 상대오차, 평균제곱오차, 상대제곱근오차, 불일치율, 그리고 S/N비를 비교한 결과, Laursen 공식(modified by Copeland)이 대상유역에 가장 적합한 것으로 분석되었다.

급곡선 탄성레일체결장치의 거동특성에 미치는 매개변수 연구 (The Parametric Study on the Performance Characteristics of Elastic Rail Fastening System on the Sharp Curved Track)

  • 백찬호;주봉규;최정열;최일윤;박용걸
    • 한국철도학회:학술대회논문집
    • /
    • 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
    • /
    • pp.2163-2173
    • /
    • 2011
  • In this study, the deformations and stresses occurred in the elastic rail fastening system were evaluated according to applied extreme track forces based on various field conditions, track curvature and poor properties. The purpose of this study is to establish a method for efficient management and suggest guide line for track construction in order to secure the performance quality of the elastic rail fastening system on the sharp curved track.. Therefore, initial construction qualities of rail and concrete bed, initial clamping force and applied extreme track forces were used into experiment as several parameters. Using these test results, the performance characteristics of the elastic rail fastening system were also evaluated. As a result, it suggested the method to secure long-term durability of fastening system and comparing sharp curved track to results on field test.

  • PDF

유동상 Media를 이용한 기존하수처리장의 Retrofitting 가능성 평가 (Evaluation on the Possibility of a Retrofitting Treatment Using Moving Media of Existing Wastewater Treatment)

  • 고태호;박운지;이찬기
    • 산업기술연구
    • /
    • 제25권A호
    • /
    • pp.133-139
    • /
    • 2005
  • In this study, as MBBR(Moving Bed Biofilm Reactor) process using waste tire media is suggested for retrofitting with advanced wastewater treatment and the removal property of organic matter and nutrient and the capacity of media are evaluated through long-term operation with pilot plant following seasons, the application capacity of retrofitting with MBBR process to a existing wastewater treatment is studied. As a result of the long-term operation of the process, it is proved that there is no loss and abrasion of media, and also that it is possible to secure the sufficient attached bio-mass. The values of organic matter and nutrient in effluent are suitable for the strict discharged water quality standards in every season including winter.

  • PDF

하천 횡단구조물에 의한 하상변동 예측 - 행정중심복합도시 주요 하천구간을 중심으로 - (A Riverbed Change Prediction by River-Crossing Structure -Focused on the Major River Reaches of the Multifunctional Administrative City-)

  • 연규성;정상만;윤찬영;이주헌;신광섭
    • 한국방재학회 논문집
    • /
    • 제9권1호
    • /
    • pp.107-113
    • /
    • 2009
  • 본 연구에서는 행정중심복합도시 예정 및 주변지역의 금강과 미호천 일부 구간을 대상으로 하상변동의 실태분석과 수위유지 시설 설치에 따른 장기 예측을 실시하였다. 1988년, 2002년 및 2007년의 횡단자료를 이용하여 대상구간의 종방향 하상변동 실태를 분석한 결과 금강과 미호천 구간 모두 2007년 최심하상고는 1988년에 비해 심한 저하가 발생된 반면 2002년에 비해서는 미소한 변화가 발생되었다. 수위유지시설 설치에 따른 하상변동 장기 예측을 수행하기 위하여 본 연구에서는 1차원 모형인 HEC-RAS 4.0 모형을 적용하였다. 고정상 모형의 수행을 통하여 수면고를 보정(calibration)하였으며, 1988년과 2002년 횡단자료를 사용하여 이동상 모형에서의 검정(verification)을 실시하였다. 2007년을 기준으로 하여 2017년까지 향후 10년간 수위유지시설의 설치 높이에 따른 시나리오별 하상변동을 예측한 결과 미호천 대상구간은 그 영향이 미미하였으나 금강 대상구간은 수위유지시설의 높이가 높을수록 많은 영향을 미치는 것으로 나타났다. 수위유지시설의 설치 높이가 7 m일 경우 금강 대상구간은 설치하지 않을 경우보다 미호천합류점 상류부근에서 1.59 m의 퇴적이 발생할 것으로 모의되었으며, 수위유지시설 하류부근에서 1.98 m의 침식이 발생할 것으로 모의되었다.

운행선상의 연약노반 시험부설구간에서의 장기계측을 통한 거동 특성 (Characteristics of Behavior of the Soft Roadbed through Long-Term Instrumentation on the Field Test)

  • 이진욱;최찬용;이성혁;이창열
    • 한국철도학회:학술대회논문집
    • /
    • 한국철도학회 2004년도 추계학술대회 논문집
    • /
    • pp.1058-1064
    • /
    • 2004
  • As one of reinforcing methods for soft roadbed, the problems that mud-pumping and settlement occurred by soft roadbed, were investigated, evaluated and analyzed through installing relatively economical and efficient geosynthetics on the selected track-bed for testing. Mock-heang to Dong-ryang on the filed resting sections in the Chung-buk lines were selected as investigating the state of track and prepared field after selecting three of 1,700 spots which often make mud-pumping and requiting maintenance for that. Long curved line radiuses(R) of Mock-heang to Dong-ryang are 500m that were installed with 4 types of geosynthetics layers and one ballast layer. Installed testing cross-section is 200m totally with 40 m between places. Strength or prepared roadbed was measured to investigate the state of roadbed and track with constructing(installing) field testing sections and physical properties of roadbed soils were evaluated and analyzed. Also, mud-pumping, settlement of elastic or plastic sleeper, failure or track, wheel-loads, transverse and earth pressures were measured after installing field testing sections.

  • PDF

현장부설시험구간에서의 장기계측을 통한 토목섬유 보강효과 (A Study on Reinforcement Effectiveness for Railway Soft Roadbed through Long-Term Instrumentation on the Field Test)

  • 최찬용;이진욱
    • 한국철도학회:학술대회논문집
    • /
    • 한국철도학회 2005년도 춘계학술대회 논문집
    • /
    • pp.734-743
    • /
    • 2005
  • In this study, geotextiles was applied on the selected track-bed, which is relatively economical and efficient way to prevent the problem of mud-pumping and settlement. Field testing sections from Mock-haeng to Dong-ryang in the Chung-La lines in Korea were selected to investigate the state of track and roadbed. And three places were chosen among 1,700 spots where mud-pumping was frequently occurred and maintenance required. At the curved section with radius of 500m between Mock-haeng and Dong-ryang, we divided this testing site into 5 section and 4 different types of geotextile were installed and left the last section with no reinforcement. Total length of the test site was 200m and individual length of each site was 40 m. In order to understand the state and the strength of prepared roadbed, stiffness and physical properties of the roadbed soil were evaluated and analyzed. Also, after the installation, mud-pumping, settlement of elastic or plastic sleeper, failure of track, wheel-loads, lateral force and earth pressures were investigated.

  • PDF

수소충전소용 유압식 압축기 안전성 시험에 관한 연구 (Hydraulic Compressor Safety Test for Hydrogen Stations)

  • 성혜진;황봄찬;최성준;김영규;조성민
    • 한국기계가공학회지
    • /
    • 제19권11호
    • /
    • pp.8-15
    • /
    • 2020
  • The government has announced its Hydrogen Economy Roadmap to strengthen global competitiveness on the hydrogen economy by focusing on hydrogen fuel cell electric vehicles and fuel cells. In this regard, the interest on the economics and safety of the infrastructure of hydrogen stations has also increased. In this study, a test bed similar to an actual hydrogen charging facility was built, and a prototype of a piston-type compressor was modeled. In this model, the piston was hydraulically compressed to progressively test leakage, leakage rate, and durability and to check for any malfunction. Moreover, the leakage rate, cylinder leak performance, and compressor operation durability were evaluated for safety; it was confirmed that there were no abnormalities. Nevertheless, an investigation of the long-term use and operating pressure of the compressor is necessary to verify the safety of developing a100-MPa domestic compressor in the future.

Glomus Tumor of the Hand

  • Lee, Won;Kwon, Soon Beom;Cho, Sang Hun;Eo, Su Rak;Kwon, Chan
    • Archives of Plastic Surgery
    • /
    • 제42권3호
    • /
    • pp.295-301
    • /
    • 2015
  • Background Glomus tumors were first described by Wood in 1812 as painful subcutaneous tubercles. It is an uncommon benign neoplasm involving the glomus body, an apparatus that involves in thermoregulation of cutaneous microvasculature. Glomus tumor constitutes 1%-5% of all hand tumors. It usually occurs at the subungual region and more commonly in aged women. Its classical clinical triad consists of pain, tenderness and temperature intolerance, especially cold sensitivity. This study reviews 15 cases of glomus tumor which were analyzed according to its anatomic location, surgical approach and histologic findings. Methods Fifteen patients with subungual glomus tumors of the hand operated on between January 2006 and March 2013, were retrospectively reviewed. Patients were evaluated preoperatively with standard physical examination including ice cube test and Love's test. Diagnostic imaging consisted of ultrasonography, computed tomography, and magnetic resonance imaging. All procedures were performed with tourniquet control under local anesthesia. Eleven patients underwent excision using the transungual approach, 3 patients using the volar approach and 1 patient using the lateral subperiosteal approach. Results Total of 15 cases were reviewed. 11 tumors were located in the nail bed, 3 in the volar pulp and 1 in the radial aspect of the finger tip. After complete excision, patients remained asymptomatic in the immediate postoperative period. In the long term follow up, patients exhibited excellent cosmetic results with no recurrence. Conclusions Accurate diagnosis should be made by physical, radiologic and pathologic examinations. Preoperative localization and complete extirpation is essential in preventing recurrence and subsequent nail deformity.

영산강의 유기물 플럭스와 장기변동에 대한 연구 (Long-term Variation and Flux of Organic Carbon in the Human-disturbed Yeongsan River, Korea)

  • 조형찬;조영길
    • 한국해양학회지:바다
    • /
    • 제22권4호
    • /
    • pp.187-198
    • /
    • 2017
  • 영산강의 유기물 농도와 플럭스를 파악하기 위하여 2006~2015년까지 10년 동안 약 2주 간격으로 영본D 지점에서 강물을 채취하여 유기물(DOC, POC)을 분석하였다. DOC 농도는 연평균 $2.49{\sim}4.39mg{\cdot}C/L$ 범위로 연중 중영양상태가 유지되었고, 조류증식 및 강수에 의한 증감에 따라 30.1% (${\sigma}_x/\bar{x}$) 변동하였다. POC는 2006년 $6.68({\pm}2.80)mg{\cdot}C/L$에서 2015년 $0.19({\pm}0.14)mg{\cdot}C/L$로 10년간 점진적으로 무려 97% 감소하였으며, 2011년 보건설을 기점으로 극적인 변화를 보였다. 이는 보에 의한 정체와 거름망 효과에 기인한 것으로서 보건설 전후로 POC와 SPM 관계의 상이함, 보건설 이후 POC와 chlorophyll-a의 관계로부터 POC의 기원 및 조성의 극명한 변화가 유도된 사실을 파악하였다. TOC 농도는 POC 감소효과로 보건설 이후 52.3% 줄었고 POC:DOC 존재형태 비 또한 DOC가 90.9%에 달하는 압도적 우위를 차지하였다. 하구언 배수량을 이용해 계산된 TOC 플럭스는 $2.56{\sim}19.41{\times}10^9g{\cdot}C/yr$ 범위에서 점진적 감소가 뚜렷하였으며, 2011년을 기점으로 전후 5년 평균 $14.54{\times}10^9g{\cdot}C/yr$에서 $5.40{\times}10^9g{\cdot}C/yr$로 62.9% 줄었다. 따라서 보건설 이후 2015년까지 $9.14{\times}10^9g{\cdot}C$, 즉 매년 약 $1.83{\times}10^9g{\cdot}C$의 유기물이 하상에 축적되었을 것으로 추정된다.

설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰 (Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013)

  • 이대영;김사량;김현정;김동선;박준석;임병찬
    • 설비공학논문집
    • /
    • 제26권12호
    • /
    • pp.605-619
    • /
    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.