• Title/Summary/Keyword: flush operation

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The evaluation of the simultaneous flow rate for sizing the water supply piping in the office building (사무소 건물의 급수배관경 산정을 위한 동시사용유량에 관한 연구)

  • 이용화
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.11 no.4
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    • pp.511-517
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    • 1999
  • Determining the simultaneous flow rate in any particular section of piping is the important step in order to determine the size of water supply piping. Now we are using the diversity curve of common water closet in order to determine the simultaneous flow rate of water supply piping, but there is a difference between a determined flow rate of general water closet and that of water closet for water saving. This study aims to find out the fixture unit of a flush valve type water closet for water saving in office building, and to determine the correlation between the fixture units and peak flow rates on the basis of the probability theory. A flush valve type water closet for water saving that have a 7.5 second duration of flush operation with an average design flow rate 72 $\ell$/fin was considered. Simulation results indicate that the number 5 is shown to be reasonable to the fixture unit of water closet for water saving. And the design can be undersized considerably with the revised diversity curves using modified fixture unit.

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Reduction of Suspended Solids in First Flush from a Building Rooftop using Various Media (여과재를 활용한 건물옥상유출 초기빗물의 부유물질 저감)

  • Kim, Seongbeom;Lee, Wontae
    • Journal of Korean Society of Environmental Engineers
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    • v.39 no.4
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    • pp.214-219
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    • 2017
  • We analyzed the water quality of first flush and rainfall runoff from a building rooftop, and investigated the removal of suspended solids (SS) in first flush using various media to develop a first flush filtration system. Particle size distribution exhibited most of particles in first flush from the rooftop ranged from 10 to 30 ${\mu}m$. SS concentrations maxed in 10~20 min and decreased afterwards. Dissolved organics and inorganic materials in runoff also showed highest levels in first flush (10 min). Filtration tests using anthracite (AC), polyurethane (PU), polypropylene (PP) showed about 50% of SS removal during the first 10 min operation, but the removal rates dramatically decreased after 20 min of filtration. Based upon the results from rinse and run cycle tests, only AC could achieve nice cycles without distinct decease of SS removal. SS removal rates increased with higher depth of media bed and lower flowrate. The system achieved over 50% of SS removal with a media depth of 30 cm and flowrate < 12 L/min.

Runoff Characteristics of Stormwater in Small City Urban Area (국내 중소 도시지역 강우유출수의 유출특성)

  • Lee, Hong-Shin;Lee, Seung-Hwan
    • Journal of Korean Society of Environmental Engineers
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    • v.31 no.3
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    • pp.193-202
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    • 2009
  • This study was conducted to identify the magnitude of first flush in small city urban area and to provide the basic information on the criteria of stormwater runoff management. Monitoring site was surrounded by residential area in Gumi city near to national industrial complex and the monitoring period was three months. Total watershed area was 24.9 ha, where 80% of the area is impervious (asphalt of pavement type). Periodic monitoring of conventional water quality parameters were conducted with six times of rainfall period. Event mean and site mean concentrations for all the parameters were calculated based on the analytical results. Particle size distribution was 9.82 ${\mu}m$ for $D_{0.1}$, 38.99 ${\mu}m$ for $D_{0.5}$ and 159.61 ${\mu}m$ for $D_{0.9}$ respectively. First flush phenomenon was detected highly in particulate solids than dissolved ones. The first flush criteria results by mass first flush contained between 44.4% to 58.5% pollutant mass during the first 30% of runoff volume. Mass first flush ratio and particle size distribution obtained in this study are expected to provide the basic information for the design and operation of non-point source treatment facility.

Impacts of Hierarchy in Ethernet Ring Networks on Service Resiliency

  • Lee, Kwang-Koog;Ryoo, Jeong-Dong;Kim, Young-Lok
    • ETRI Journal
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    • v.34 no.2
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    • pp.199-209
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    • 2012
  • In transport networks, a multi-ring architecture is very useful to facilitate network planning and to design and provide more resilient services for customers. Unlike traditional synchronous optical network multi-rings, the service resiliency of Ethernet-based multi-rings is significantly impacted by the ring hierarchy because a link or node failure in a certain level ring triggers filtering database flush actions in all higher level rings as well as in the ring with the failure, and consequently a large amount of duplicated data frames may be flooded. In this paper, we investigate how the ring hierarchy impacts the service resiliency of multi-ring networks. Based on extensive experiments on various single- and multiple-link failures, we suggest two effective inter-ring connection rules to minimize the transient traffic and to ensure more resilient multi-ring networks. In addition, we consider a flush optimization technique called e-ADV, and show that the combination of e-ADV and multi-ring structures satisfying our inter-ring connection rules results in a more attractive survivability performance.

MLC-LFU : The Multi-Level Buffer Cache Management Policy for Flash Memory (MLC-LFU : 플래시 메모리를 위한 멀티레벨 버퍼 캐시 관리 정책)

  • Ok, Dong-Seok;Lee, Tae-Hoon;Chung, Ki-Dong
    • Journal of KIISE:Computing Practices and Letters
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    • v.15 no.1
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    • pp.14-20
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    • 2009
  • Recently, NAND flash memory is used not only for portable devices, but also for personal computers and server computers. Buffer cache replacement policies for the hard disks such as LRU and LFU are not good for NAND flash memories because they do not consider about the characteristics of NAND flash memory. CFLRU and its variants, CFLRU/C, CFLRU/E and DL-CFLRU/E(CFLRUs) are the buffer cache replacement policies considered about the characteristics of NAND flash memories, but their performances are not better than those of LRD. In this paper, we propose a new buffer cache replacement policy for NAND flash memory. Which is based on LFU and is taking into account the characteristics of NAND flash memory. And we estimate the performance of hit ratio and flush operation numbers. The proposed policy shows better hit ratio and the number of flush operation than any other policies.

UHPLC System Shutdown and Reactivation Advice (UHPLC 시스템 종료 및 재가동 시 가이드)

  • Mark Fever;Gemma Lo
    • FOCUS: LIFE SCIENCE
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    • no.1
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    • pp.8.1-8.3
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    • 2024
  • Ultra-high performance liquid chromatography (UHPLC) systems are integral to modern analytical laboratories, necessitating careful maintenance and operation protocols to ensure optimal performance. This document provides comprehensive guidelines for the proper shutdown and reactivation of UHPLC systems to prevent damage and maintain operational efficiency. • Shutdown: Remove the column and replace it with a union to avoid blockages. Flush the system with a compatible solvent mix, clean mobile phase reservoirs to prevent microbial growth, flush the pump with storage solvent, and clean the autosampler, including the needle and injection port. • Reactivation: Inspect the system for wear or damage, gradually reintroduce mobile phases starting with a weak solvent, reinstall the column securely, and perform system checks on baseline stability, pressure consistency, and detector performance. By adhering to these guidelines, laboratories can ensure the longevity and reliability of their UHPLC systems, maintaining high analytical performance and minimizing downtime. These procedures help prevent common issues such as blockages, contamination, and component wear, thereby supporting efficient and accurate analytical operations.

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An Experimental Study on Characteristics of Sprinkler Head Activation in Low Growth Rate Fire (저성장속도 화재에서의 스프링클러 헤드 동작특성에 관한 실험적 연구)

  • Choi, Yong-Seob;Yoon, Jong-Chil
    • Fire Science and Engineering
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    • v.30 no.5
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    • pp.26-35
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    • 2016
  • Sprinkler installations shall be operated at normal operating temperature of the atmosphere as a fire sprinkler head in any facility to control and extinguish the fire when the fire initially. Recently, however, some flush type quick response automatic sprinkler heads in slow fire place is a problem that can not be normal operation are raised. In this paper, by using the experimental model of the Apartment house of Commons and Cabinet burner size bedrooms fire conditions to form a slow growth rate and can supply more than 0.2 MPa pressure is the minimum pressure that can be applied inside the pipe in the field experiment was conducted. In the majority of experiments lush type quick response automatic sprinkler heads which is used in the country it was confirmed to be incompletely opened as the Cold Soldering occur. This phenomenon is likely to fail early fire suppression and control because they can cause the spread of fire and casualties needed to complement domestic product testing and type approval standards through additional research.

Management of Swimming Pool (수영장 관리)

  • Kim Kyong-Ho
    • Journal of environmental and Sanitary engineering
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    • v.4 no.1 s.6
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    • pp.37-42
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    • 1989
  • Management of Swimming pool is focused on Swimming pool samitation in relation with chlorination of swimming water and potable water, disposal of waste and excrement within the boundry of swimming pool that may be summerised as follows: 1. Chlorination of Swimming Water Residual chlorine must be kept within the range of $0.4\~0.6 mg/l$ and in case of chloramine should be $0.7\~1.0mg/l$ while swimming pool is in operation 2. Chlorination of potable Water Residual chlorine must be kept within the rangs of $0.2\~04 mg/l$ at all time 3. Disposal of litters must be kept in the water tight waste bin with fitted lid, and waste should not be overflow -out of the bin. When waste in landfilled, the sufficient amount of cover material should be used daily. 4. Disposal of excrement Toilet must be water-flush type. However, The establishment of pit latrine is unavoidable the excrement must be covered with lime or dirt so that excrement should not be exposed to air.

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Posterior Cruciate Ligament Reconstruction by Tibial Inlay Technique (Tibial Inlay 방법을 이용한 후방 십자 인대 재건술의 결과)

  • Song Eun Kyoo;Yoon Taek Rim;Jung Jong Wook;Kim Jong Seon
    • Journal of the Korean Arthroscopy Society
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    • v.5 no.2
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    • pp.80-84
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    • 2001
  • Purpose : To evaluate the clinical and radiological results of posterior cruciate ligament reconstruction(PCL) by tibial inlay technique. Materials and Methods : Twenty four patients(25 cases), who underwent reconstruction of posterior cruciate ligament by tibial inlay technique and were followed up for at least 2 years, were reviewed retrospectively. Mean age at operation was 35 years and mean period of follow up was 34 months. Clinically Lysholm knee socre, posterior drawer test and step off sign were evaluated. Instrumented posterior laxity test with $Telos^{\circledR}$ device(Telos stress device; Austin & Associates, Inc., Polston, US) was performed. Results : Lysholm knee score was improved from 56.9 points preoperatively to 94.6 points at fellow up. Posterior drawer test showed grade II instability in 1 case, grade III in 18 and Grade IV in 6 preoperatively and improved to grade I In 12, grade II in 10 and grade III in 3 at follow up. Step off signs were changed from -10mm in 6 cases, -5mm in 18 and flush in 1 preoperatively to -5mm in 3, flush in 10 and +5mm in 12 at follow up. Side to side difference of instrumented posterior laxity test was improved front 13.6mm preoperatively to 4.3mm at follow up. Conclusions : PCL reconstruction by tibial inlay technique is considered to be a good treatment method to restore posterior stability of the knee, which could result in satisfactory clinical and radiological results at more than 2 years' follow up.

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Selection of Best Management Practices for Urban Watershed Corresponding to the Runoff Characteristics from Non-point Pollution Sources (도시지역의 비점오염유출특성을 고려한 도시하천 적정관리방안)

  • Chi, Hong-Jin;Shin, Gwy-Am
    • Journal of Environmental Science International
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    • v.25 no.1
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    • pp.31-40
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    • 2016
  • The purpose of this study was to analyse the runoff characteristics of non-point pollution sources in an urban watershed and determine the effectiveness of newly installed riverwater treatment system to reduce water pollution caused by storm runoff in the urban watershed. The results of this study showed that the levels of BOD5 and suspended solid were highly influenced by first-flush effect and the pollutant load of those two parameters were also very high in the urban watershed. Meanwhile, the effectiveness of riverwater treatment system to reduce the levels of BOD5 and suspended solid was relatively high, but those to reduce the levels of T-N and T-P was low, which needs some additional unit treatment process such as filtration and coagulation. Nonetheless, the riverwater treatment system tested was relatively simple in installation and operation, effective in removing many water pollutants and, most importantly, does not require much space as other treatment systems, so it could be an attractive alternative option to reduce riverwater pollution caused by storm runoff in urban watersheds.