• Title/Summary/Keyword: critical bubble

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Rewriting Georgic: Anna Letitia Barbauld's "Washing-Day" (죠직 다시 쓰기 -아나 레티셔 바볼드의 「빨래하는 날」)

  • Shin, Kyung-Sook
    • Journal of English Language & Literature
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    • v.56 no.5
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    • pp.947-971
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    • 2010
  • Anna Letitia Barbauld's poem "Washing-Day" (1797) has sparked a variety of feminist critical endeavors over the past two decades. While many feminist literary critics try to salvage the poem as a successful tongue-in-cheek riposte directed at the male dominant literary world, more rigorous Marxist feminists accuse Barbauld of being limited by her own middle-class woman's view on women's domestic labor. Legitimate as they may be, these readings fail to elucidate Barbauld's place in a larger literary and intellectual discourse during the eighteenth century. In this paper I read "Washing-Day" as a woman's georgic, a genre or mode concerned with agricultural labor, the public value of which was highly recognized in eighteenth-century England. Alluding to canonical texts by writers like Shakespeare, Milton, and Pope, Barbauld's "loaded lines" in mock-heroic form create a space in which the women's domestic labor of washing interrupts men's daily routines and disrupts their poetic assumptions. While she makes women's work visible, Barbauld also addresses its quintessential nature. Women's work is affective labor; women have to labor physically and mentally to produce the desired domestic comfort. By allowing the image of the soap "bubble" to echo with many "bubbles" in other writers' texts, from the soap bubbles the narrator used to play with as a child to the hot-air balloon "bubble" of the Montgolfier brothers, Barbauld pleasantly equates work and day-dreaming, men's toil and children's play, and finally public, scientific, and recognized labor and private, domestic, and imaginative activities.

An Experimental Study on the Measurement of Water Surface Discharge Temperature of High-Temperature Bubble Injected into Cylindrical Acrylic Water Tank (원통 아크릴 수조로 주입된 고온 기포의 수면 배출 온도 측정에 관한 실험적 연구)

  • SeokTae Yoon;YongJin Cho
    • Journal of Korea Society of Industrial Information Systems
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    • v.28 no.6
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    • pp.99-105
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    • 2023
  • Submarines, which require a high degree of survivability, are among the most critical combat weapon systems in military strategic assets. Conventional submarines need air to operate their propulsion systems. Exhaust gases released into the water during snorkel navigation heat the surrounding fluid, producing a temperature wake. This wake, in turn, reduces the submarine's survivability. In this study, we conducted a preliminary experiment on the temperature traces formed by an underwater submarine's waste discharge. For this purpose, we collected propulsion system and navigation condition data from domestically introduced submarines and developed an experimental system to measure the temperature traces. As a result, we observed that high-temperature bubbles injected into the tank broke down into smaller sizes, and their temperature dropped to levels similar to the surrounding fluid. This observation was confirmed using a thermocouple sensor. Consequently, the thermal imaging system designed to measure the temperature trace of the water's surface did not detect any significant temperature traces.

Synthesis and Characterization of Interfacial Properties of a Cationic Surfactant Having Three Hydroxyl Groups (세 개의 히드록실기를 가진 양이온 계면활성제 합성 및 계면 특성에 관한 연구)

  • Lee, Byung Min;Kim, Ji-Hyun;Kim, Sung Soo;Lim, Jong Choo
    • Applied Chemistry for Engineering
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    • v.23 no.5
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    • pp.433-439
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    • 2012
  • In this study, a cationic surfactant BHMAS (N,N-bis-(3'-n-dodecyloxy-2'-hydroxypropyl)-N-methyl-2-hydroxyethylammonium methyl sulfate) having two lauryl and three hydroxyl groups was synthesized by the reaction of n-dodecyl glycidyl ether and 2-aminoethanol followed by the quarternization with dimethyl sulfate. The structure of the product was elucidated by $^{1}H-NMR$ and FT-IR. The CMC (critical micelle concentration) and surface tension of BHMAS at CMC condition were found to be $9.12\;{\times}\;10^{-4}$ mol/L and 28.71 mN/m respectively. Dynamic surface tension measurements using a maximum bubble pressure tensiometer indicated that a relatively long time was required to saturate the interface between air and aqueous surfactant solution. The interfacial tension measured between 1 wt% surfactant solution and n-decane reached an equilibrium value of 0.045 mN/m in 5 min. The adsorption capacity of the synthesized surfactant was observed to be excellent, which suggests that the surfactant can be used as a softening agent during a laundry process.

Effects of the Free-Stream Turbulence and Surface Trip Wire on the Flow past a Sphere (자유류 난류와 표면 트립 와이어가 구 주위 유동에 미치는 영향)

  • Son, Kwang-Min;Choi, Jin;Jeon, Woo-Pyung;Choi, Hae-Cheon
    • 유체기계공업학회:학술대회논문집
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    • 2006.08a
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    • pp.187-190
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    • 2006
  • In the present study, effects of tree-stream turbulence and surface trip wire on the flow past a sphere at $Re\;=\;0.4\;{\times}\;10^5\;{\sim}\;2.8\;{\times}\;10^5$ are investigated through wind tunnel experiments. Various types of grids are installed upstream of the sphere in order to change the tree-stream turbulence intensity. In the case of surface trip wire, 0.5mm and 2mm trip wires are attached from $20^{\circ}\;{\sim}\;90^{\circ}$ at $10^{\circ}$ interval along the streamwise direction. To investigate the flow around a sphere, drag measurement using a load cell, surface-pressure measurement, surface visualization using oil-flow pattern and near-wall velocity measurement using an I-type hot-wire probe are conducted. In the variation of free-stream turbulence, the critical Reynolds number decreases and drag crisis occurs earlier with increasing turbulence intensity. With increasing Reynolds number, the laminar separation point moves downstream, but the reattachment point after laminar separation and the main separation point are fixed, resulting in constant drag coefficient at each free-stream turbulence intensity. At the supercritical regime, as Reynolds number is further increased, the separation bubble is regressed but the reattachment and the main separation points are fixed. In the case of surface trip wire directly disturbing the boundary layer flow, the critical Reynolds number decreases further with trip wire located more downstream. However, the drag coefficient after drag crisis remains constant irrespective of the trip location.

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Cooling performance test of the superconducting fault current limiter

  • Yeom, H.;Hong, Y.J.;In, S.;Ko, J.;Kim, H.B.;Park, S.J.;Kim, H.;Kim, H.R.
    • Progress in Superconductivity and Cryogenics
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    • v.16 no.4
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    • pp.66-70
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    • 2014
  • The superconducting fault current limiter (SFCL) is an electrical power system device that detects the fault current automatically and limits the magnitude of the current below a certain safety level. The SFCL module does not have any electrical resistance below the critical temperature, which facilitates lossless power transmission in the electric power system. Once given the fault current, however, the superconducting conductor exhibits extremely high electrical resistance, and the magnitude of the current is accordingly limited to a low value. Therefore, SFCL should be maintained at a temperature below the critical temperature, which justifies the cryogenic cooling system as a mandatory component. This report is a study which reported on the cooling system for the 154 kV-class hybrid SFCL owned by Korea Electric Power Corporation (KEPCO). Using the cryocooler, the temperature of liquid nitrogen (LN2) was lowered to 71 K. The cryostat was pressurized to 5 bars to improve the dielectric strength of nitrogen and suppress nitrogen bubble foaming during operation of SFCL. The SFCL module was immersed in the liquid nitrogen of the cryostat to maintain the superconducting state. The performance test results of the key components such as cryocooler, LN2 circulation pump, cold box, and pressure builder are shown in this paper.

MULTI-SCALE MODELING AND ANALYSIS OF CONVECTIVE BOILING: TOWARDS THE PREDICTION OF CHF IN ROD BUNDLES

  • Niceno, B.;Sato, Y.;Badillo, A.;Andreani, M.
    • Nuclear Engineering and Technology
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    • v.42 no.6
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    • pp.620-635
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    • 2010
  • In this paper we describe current activities on the project Multi-Scale Modeling and Analysis of convective boiling (MSMA), conducted jointly by the Paul Scherrer Institute (PSI) and the Swiss Nuclear Utilities (Swissnuclear). The long-term aim of the MSMA project is to formulate improved closure laws for Computational Fluid Dynamics (CFD) simulations for prediction of convective boiling and eventually of the Critical Heat Flux (CHF). As boiling is controlled by the competition of numerous phenomena at various length and time scales, a multi-scale approach is employed to tackle the problem at different scales. In the MSMA project, the scales on which we focus range from the CFD scale (macro-scale), bubble size scale (meso-scale), liquid micro-layer and triple interline scale (micro-scale), and molecular scale (nano-scale). The current focus of the project is on micro- and meso-scales modeling. The numerical framework comprises a highly efficient, parallel DNS solver, the PSI-BOIL code. The code has incorporated an Immersed Boundary Method (IBM) to tackle complex geometries. For simulation of meso-scales (bubbles), we use the Constrained Interpolation Profile method: Conservative Semi-Lagrangian $2^{nd}$ order (CIP-CSL2). The phase change is described either by applying conventional jump conditions at the interface, or by using the Phase Field (PF) approach. In this work, we present selected results for flows in complex geometry using the IBM, selected bubbly flow simulations using the CIP-CSL2 method and results for phase change using the PF approach. In the subsequent stage of the project, the importance of effects of nano-scale processes on the global boiling heat transfer will be evaluated. To validate the models, more experimental information will be needed in the future, so it is expected that the MSMA project will become the seed for a long-term, combined theoretical and experimental program.

An Experimental Study on the Superheated Liquid Jet (과열액체제트의 미립화에 관한 실험적 연구)

  • Lee J. G.;Lee S. Y.;Kim I. G.
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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    • v.16 no.1
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    • pp.89-102
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    • 1987
  • Experiments have been carried out to study the atomisation characteristics of superheated liquid(water) jet injected into the atmosphere through a single-hole nozzle. In present experi-mental range, superheated liquid jet has been observed to be atomised in two-phase effluent type; that is, spray formed by the bubble nucleation in the nozzle. In case of liquid injection through a long nozzle (L/D=29.09), the critical superheat for occurrence of two-phase effluent atomisa-tion can be determined from sudden change of spray angle. Sauter mean diameter of the spray droplets decreases as the degree of superheat increases. For the short nozzle (L/D=7.27), mean diameter increases with the injection pressure, while it decreases for the long nozzle; however for the long nozzle the effect of injection pressure is not significant compared with the short nozzle. For the short nozzle the uniformity of drop size distribution increases with increasing the degree of superheat, but for the long nozzle the effect of superheat on the uniformity is not appreciable.

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Effect of Orientation on Pool Boiling Heat Transfer in Annulus with Small Gap (경사각이 좁은 틈새를 가지는 환상공간 내부 풀비등 열전달에 미치는 영향)

  • Kang, Myeong-Gie
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.3
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    • pp.237-244
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    • 2011
  • An experimental study was carried out to investigate the effect of the inclination angle on the nucleate pool boiling of saturated water at atmospheric pressure. We considered an annulus with a gap of 5 mm and a bottom opening. The inner tube of the annulus was heated, and the outer diameter and the length of the tube were 25.4 mm and 500 mm, respectively. The inclination angle was varied from horizontal to vertical. The results were compared to those for an annulus with a larger gap and a single tube. In the small-gap annulus, the effect of the inclination angle on the heat transfer was not significant. However, an early onset of the critical heat flux was observed at 80 kW/$m^2$ when the annulus was horizontal. Liquid agitation and bubble coalescence were considered to be the major heat-transfer mechanisms.

Estimation and Determinants on Residential Investment Profits in Seoul: A Focus on Housing Transaction Price from 2010 to 2018 (서울시 주택 예상투자이익 추정과 영향요인에 대한 시론적 분석 - 2010-2018년 주택 실거래가를 중심으로 -)

  • Ahn, Hye-Sung;Kang, Chang-Deok
    • Journal of the Korean Regional Science Association
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    • v.36 no.1
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    • pp.37-50
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    • 2020
  • Estimating investment profits of real estate is critical to understand real estate markets and create relevant policy as real estate market and capital market combines closely. Thus, this study applied the concept of Tobin's Q to estimate investment profits for apartments as well as row-houses and multi-family homes in Seoul from 2010 to 2018. Investment profits were estimated by two approaches: subtracting the replacement cost from the transaction price and calculating ratio of the transaction price to the replacement cost, respectively. The spatio-temporal changes in investment profits were apparent in apartments compared with row-houses and multi-family homes. As a result of analyzing the spatial econometrics models, the investment profit was higher in the area with high density and new developments regardless of the housing types. The framework and key findings would be the effective reference to understand residential investment behavior, create relevant housing policy, introduce value capture of windfall, measure regional competitiveness, and estimate housing bubble.

Sterilization of Seawater for the Ballast Water Management System (선박평형수 관리시스템을 위한 해수 살균법)

  • YUN, YONGSUP;CHOI, JONGBEOM;KANG, JUN;LEE, MYEONGHOON
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2016.11a
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    • pp.172-172
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    • 2016
  • The International Maritime Organization(IMO) adopted the International Convention for the Control and Management of Ships' Ballast Water and Sediments in 2004 to prevent the transfer of aquatic organisms via ballast water. Forty ballast water treatment systems were granted final approval. A variety of techniques have been developed for ballast water treatment including UV treatment, indirect or direct electrolysis, ozone treatment, chemical compounds and plasma-arc method. In particular, using plasma and ozone nano-bubble treatments have been attracted in the fields. However, these treatment systems have a problem such as remained toxic substance, demand for high power source, low efficiency, ets. In this paper, we present our strilization results obtained from membrane type electrolytic-reduction treatment system The core of an electrolysis unit is an electrochemical cell, which is filled with pure water and has two electrodes connected with an external power supply. At a certain voltage, which is called critical voltage, between both electrodes, the electrodes start to produce hydrogen gas at the negatively biased electrode and oxygen gas at the positively biased electrode. The amount of gases produced per unit time is directly related to the current that passes through the electrochemical cell. From the results, we could confirm the sterilization effect of bacteria such as S. aureus, E. Coli and demonstrate the mechanism of sterilization phenomena by electrolytic-reduction treatment system.

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