• Title/Summary/Keyword: glass pipe

Search Result 104, Processing Time 0.022 seconds

A Comparative Study on the Testing Methods for the Analysis of Tensile Strength of GERP Rebars (GFRP 보강근의 인장강도 분석을 위한 시험방법 비교 연구)

  • You, Young-Chan;Park, Ji-Sun;You, Young-Jun;Park, Young-Hwan
    • Journal of the Korea Concrete Institute
    • /
    • v.18 no.3 s.93
    • /
    • pp.303-312
    • /
    • 2006
  • The main objective of this experimental study is to examine the feasibilities of each testing method with various kinds of grip systems for the analysis of tensile strength of GFRP(glass fiber reinforced polymer) reinforcing bars. Three types of grip systems were examined such as resin-sleeved pipe-type grip proposed by CSA(Canadian Standard Association), frictional resistance type metal grip by ASTM(American Standard for Testing and Materials) and wedge-inserted cone-type grip normally used in prestressing tendons. Also, mechanical properties of GFRP rebars with different surface deformations were investigated for each different type of testing grip used in this study. All testing procedures including specimens preparation, set-up of test equipments and measuring devices were made according to the CSA S806-02 recommendations. From the test results, it was found that the highest tensile strengths of GFRP rebars were observed when tested by resin-sleeved grip system regardless of their different surface deformations. But tensile strengths of GFRP rebars by ASTM grip system are only 10% less than those by CSA grip system. On the other hand, CSA grip is not only difficult to prepare but also not disposable. Therefore, ASTM grip system is recommended as a practical alternative to estimate the tensile strength of GFRP rebars.

Study on Prediction of Performance with Design Variables of Solar-Assisted Still Using Waste Heat from Diesel Generator (디젤 발전기 폐열을 활용한 태양열원 해수담수기의 설계변수에 따른 성능 예측에 관한 연구)

  • Jang, Hyun;Yi, Chung Seob;Suh, Jeong Se;Jeong, Kyoung Yul;Park, Change Dae
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.37 no.12
    • /
    • pp.1061-1068
    • /
    • 2013
  • This study predicts distillate productions according to design variables by numerical analysis when the waste heat from a diesel generator is added to the solar-assisted still proposed in a previous study. Mathematical models were set up in reference to previous studies, and the amount of heat exchange from the waste heat recovery pipe was considered. To ensure the reliability of numerical analysis, the result was compared with that of a previous study and then, the distillate productions according to design variables were obtained by the analysis model. The results were found to generally be in agreement, and the increasing amount of distillate production of the still with the added waste heat was confirmed. In addition, the optimal value of the tilt angle of glass cover and the number of cells were determined by numerical analysis.

Swimming Motion of Flagellated Bacteria Under Low Shear Flow Conditions (느린 전단흐름에서 편모운동에 의한 대장균의 거동 특성)

  • Ahn, Yong-Tae;Shin, Hang-Sik
    • Journal of Korean Society of Environmental Engineers
    • /
    • v.33 no.3
    • /
    • pp.191-195
    • /
    • 2011
  • The measurement and prediction of bacterial transport of bacteria in aquatic systems is of fundamental importance to a variety of fields such as groundwater bioremediation ascending urinary tract infection. The motility of pathogenic bacteria is, however, often missing when considering pathogen translocation prediction. Previously, it was reported that flagellated E. coli can translate upstream under low shear flow conditions. The upstream swimming of flagellated microorganisms depends on hydrodynamic interaction between cell body and surrounding fluid flow. In this study, we used a breathable microfluidic device to image swimming E. coli at a glass surface under low shear flow condition. The tendency of upstream swimming motion was expressed in terms of 'A' value in parabolic equation ($y=Ax^2+Bx+C$). It was observed that high shear flow rate increased the 'A' value as the shear force acting on bacterium increased. Shorter bacterium turned more tightly into the flow as they swim faster and experience less drag force. The result obtained in this study might be relevant in studying the fate and transport of bacterium under low shear flow environment such as irrigation pipe, water distribution system, and urethral catheter.

Development of Plasma Reactor of Dielectric Barrier Discharge for Water Treatment (수처리용 유전체 장벽 방전 플라즈마 반응기 개발)

  • Kim, Dong-Seog;Park, Young-Seek
    • Journal of Environmental Science International
    • /
    • v.21 no.5
    • /
    • pp.597-603
    • /
    • 2012
  • Non-thermal plasma processing using a dielectric barrier discharge (DBD) has been investigated as an alternative method for the degradation of non-biodegradable organic compounds in wastewater. The active species such as OH radical, produced by the electrical discharge may play an important role in degrading organic compound in water. The degradation of N, N-Dimethyl-4-nitrosoaniline (RNO) was investigated as an indicator of the generation of OH radical. The DBD plasma reactor of this study consisted of a plasma reactor, recycling pump, power supply and reservoir. The effect of diameter of external reactor (15 ~ 40 mm), width of ground electrode (2.5 ~ 30 cm), shape (pipe, spring) and material (copper, stainless steel and titanium) of ground electrode, water circulation rate (3.1 ~ 54.8 cm/s), air flow rate (0.5 ~ 3.0 L/min) and ratio of packing material (0 ~ 100 %) were evaluated. The experimental results showed that shape and materials of ground were not influenced the RNO degradation. Optimum diameter of external reactor, water circulation rate and air flow rate for RNO degradation were 30 mm, 25.4 cm/s and 4 L/min, respectively. Ground electrode length to get the maximum RNO degradation was 30 cm, which was same as reactor length. Filling up of glass beads decreased the RNO degradation. Among the experimented parameters, air flow rate was most important parameters which are influenced the decomposition of RNO.

A numerical study on the safety of tunnel face using face bolting method (페이스 볼트 공법을 이용한 터널 막장 안정성에 관한 수치해석적 연구)

  • Ra, Jee-Hyun;Yoon, Ji-Sun
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.9 no.1
    • /
    • pp.83-89
    • /
    • 2007
  • As tunnel excavation generats stress release, a stability security of tunnel face is mainly important in case of tunnel excavation in the weak grounds. Using the steel bar or glass fiber pipe which had regular hardness, a face bolt method to reinforce previously is applied to an excavation object tunnel face aspect among measures methods regarding this. Therefore, used $FLAC^{3D}$ Ver. 2.1 on 5 Case of 0.5D (2EA), 1.0D, 1.5D, 2.0D with the length and 6 Case of 0, 20, 40, 60, 80, 100EA with the number of the bolt that a face bolt method was installed at these papers in the necessary weak grounds in order to review applicability of the tunnel face reinforcement method that used these face bolts, and executed three dimension continuous analysis.

  • PDF

A Study on the Work Breakdown Structure of Agricultural Facilities for Developing a Construction and Maintenance Information System -Focused on Vinyl house, Glass greenhouse, Cattle shed- (농촌시설물 시공 및 유지관리 정보화 시스템 구축을 위한 작업분류체계 구축에 관한 연구 -비닐하우스, 유리온실, 축사를 중심으로-)

  • Choi, Oh-Young;Kim, Tae-Hui;Kim, Jae-Yeob;Kim, Gwang-Hee;Choi, Eung-Kyoo
    • Journal of the Korea Institute of Building Construction
    • /
    • v.9 no.4
    • /
    • pp.147-155
    • /
    • 2009
  • Recently, the scale and technical complexity of agricultural production has been growing. Therefore, agricultural facilities are being gradually diversified, expanded, and made more complex. To furnish Korea's agricultural industry with international competitiveness, it is thus necessary to introduce new management techniques. The PCM (procurement-construction-maintenance) information management system for agricultural facilities is established by setting up its WBS (work breakdown structure). In this study, the WBS of a facility such as facility, space, element, works, and resources is analyzed. Following this analysts, a WBS of an agricultural facility that is appropriate for the PCM information system of an agricultural facility, is proposed by deriving it from actual WBS.

Model Experiments and Behavior Analyses of The Tunnel Support Using TDR Sensor (TDR센서를 이용한 터널 지보재의 모형 실험과 거동해석)

  • Park, Min-Cheol;Han, Heui-Soo;Cho, Jae-Ho;Yang, Nam-Young
    • Journal of the Korean GEO-environmental Society
    • /
    • v.12 no.9
    • /
    • pp.35-45
    • /
    • 2011
  • This paper is to analyze the behaviors of tunnel support by TDR(Time Domain Reflectometry) sensor using electrical pulse. To analysis the behaviors of tunnel support, Copper tape as sensing materials was studied for on-site installation. Copper tape to the top of the glass tape, foam tape, and shielding the lower part was used electromagnetic shield sheet. For a high sensitivity to load and fill out the measurement noise emissions has been developed for the production of materials. This sensing material through the tunnel model tests for the change by surcharge load in TDR data were analyzed. Varing stiffness and support of conditions were determined the change of TDR data through PVC pipe tunnel section model tests. By comparing TDR data and finite element analysis, the behaviors of the tunnel support materials were analyzed qualitatively.

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 (설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.26 no.12
    • /
    • 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.

Environmental Prediction in Greenhouse According to Modified Greenhouse Structure and Heat Exchanger Location for Efficient Thermal Energy Management (효율적인 열에너지 관리를 위한 온실 형상 및 열 교환 장치 위치 개선에 따른 온실 내부 환경 예측)

  • Jeong, In Seon;Lee, Chung Geon;Cho, La Hoon;Park, Sun Yong;Kim, Seok Jun;Kim, Dae Hyun;Oh, Jae-Heun
    • Journal of Bio-Environment Control
    • /
    • v.30 no.4
    • /
    • pp.278-286
    • /
    • 2021
  • In this study, based on the Computational Fluid Dynamics (CFD) simulation model developed through previous study, inner environmenct of the modified glass greenhouse was predicted. Also, suggested the optimal shape of the greenhouse and location of the heat exchangers for heat energy management of the greenhouse using the developed model. For efficient heating energy management, the glass greenhouse was modified by changing the cross-section design and the location of the heat exchanger. The optimal cross-section design was selected based on the cross-section design standard of Republic of Korea's glass greenhouse, and the Fan Coil Unit(FCU) and the radiating pipe were re-positioned based on "Standard of greenhouse environment design" to enhance energy saving efficiency. The simulation analysis was performed to predict the inner temperature distribution and heat transfer with the modified greenhouse structure using the developed inner environment prediction model. As a result of simulation, the mean temperature and uniformity of the modified greenhouse were 0.65℃, 0.75%p higher than those of the control greenhouse, respectively. Also, the maximum deviation decreased by an average of 0.25℃. And the mean age of air was 18 sec. lower than that of the control greenhouse. It was confirmed that efficient heating energy management was possible in the modified greenhouse, when considered the temperature uniformity and the ventilation performance.

Characteristic Analysis and Effect of Particulate Material in Drinking Water Distribution Networks (상수도관망에서 입자성 물질의 특성분석 및 영향조사)

  • Kim, Do-Hwan;Lee, Doo-Jin;Hwang, Jin-Su;Choi, Doo-Yong
    • Journal of Korean Society of Environmental Engineers
    • /
    • v.35 no.5
    • /
    • pp.312-320
    • /
    • 2013
  • Particulates in drinking water distribution system (DWDS) are mostly influenced by internal corrosion of metal pipes and sediment in pipelines due to the solution of this effect is limited. The particle size, component and properties of compounds for particulates in distributed water are different and the difference of these characteristics will be occurred by the kind of facilities, pipe condition, external factors and supply system etc. In this study, conducting the investigation of water quality in DWDS researches with particulates in the water. Monitoring sites were each water supply reservoir and the end of water supply area in DWDS. To collect particulate material at each sampling site, $47{\phi}$ glass microfiber filter type GF/C was performed using a filtration. Substances that the effect of the turbidity in the water according to particulate suspended solids and inorganic materials is due to the increasing particulates in the end of DWDS were increased. The result of compounds analysis by using X-ray diffraction (XRD) were Goethite (${\alpha}$-FeOOH), Magnetite ($Fe_3O_4$) in the end of DWDS and Quartz ($SiO_2$), Yeelimite ($Ca_4Al_6O_{12}SO_4$) at the effluent of waterworks and reservoirs. There were differences the compounds and sediments in the releasing or remaining water distribution facilities.