• Title/Summary/Keyword: Lateral spreading

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An Experimental Study on the Break-up Characteristics of Twin-Fluid Nozze According to tile Variations of Feeding Mass-ratio (공급 질량비 변화에 따른 2유체 노즐의 액주분열특성에 관한 실험적 연구)

  • Kang, S.J.;Oh, J.H.;Rho, B.J.
    • Journal of ILASS-Korea
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    • v.1 no.1
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    • pp.63-75
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    • 1996
  • The purpose of this study is to investigate the break-up characteristics by taking advantage of a two-phase coaxial nozzle. Air and water are utilized as working fluids and the mass ratio air/water has been controlled to characterize the atomization, diffusion and development of mixing process. By way of a photographic technique, conventional developing structures and diffusion angles have been analyzed systematically with variations of mass ratios. The turbulent flow components of the atomized particles were measured by a two channel LDV system and the data were treated by an on-lined measurement equipment. According to the photographic results the spreading angles decreased because the axial inertia moment was relatively higher than the lateral one with respect to the increase of mass ratio. It is found the jet flow diffuses linearly in a certain limit region while the atomizing characteristics, in terms of the distributions of particle diameters did not show particular differences. It may be expected that these fundamental results can be used as reference data in studying the atomization, breakup and diffusions.

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A Case Study on the Investigation of Vehicle Fire According to Drive Train (구동방식에 따른 승용차 엔진룸 화재조사 기법에 관한 사례 연구)

  • Son, J.B.;Kwon, H.H.;Lee, J.I.;Choi, D.M.
    • Journal of Korean Institute of Fire Investigation
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    • v.11 no.1
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    • pp.83-88
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    • 2008
  • The fire outbreaking origin of vehicle fire would be classified into two positions such as engine room and passenger room of vehicle. As a firewall is installed between engine room and passenger room, in case of engine fire, it could be assumed that it takes about 10 to 15 minutes for the fire to spread into passenger room There are two different vehicle engine layouts such as transversal and lateral layout, and the fire spreading process and resulting damage patterns on left and right side dash-panel are different depending on the engine layouts. In accordance, the first thing to do for correct and speedy finding of the fire origin place is considered to be an investigation into the dash-panel damage in case of engine room fire investigation.

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The effects of discharge gases in the voltage transfer curve of ac-PDP (ac-PDP의 전압전달특성에 미치는 방전가스의 영향)

  • Son, J.B.;Lee, S.H.;Kim, D.H.;Kim, Y.D.;Cho, J.S.;Park, J.H.
    • Proceedings of the KIEE Conference
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    • 1999.07e
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    • pp.2233-2235
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    • 1999
  • The ac plasma display panel(PDP) is a flat light-emitting gas discharge device. Discharge gases directly take effects to the discharge phenomena of ac PDP. Therefore it is necessary to understand the characteristics of the discharge gases. In this paper, we have studied the effects of discharge gases by voltage transfer curves which show the discharge characteristics of ac PDP and the change of the effective wall capacitance during a discharge which depends on lateral spreading of charge distribution and the strength of discharge. As gas pressure increases, memory margins increases. and the firing voltage of a mixed gas is lower than that of a single gas such as He gas. The minimum sustain voltage and the maximum sustain voltage or firing voltage increases with decrease in the frequency. The effective wall capacitance increases as the discharge strength that is, the gap voltage between discharge electrodes increases.

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Investigation on the Effect of Organic Additives on the Electroformed Cu Deposits with Micro-patterns (유기물 첨가제가 마이크로 패턴 구리 전주 도금에 미치는 영향 연구)

  • Lee, Joo-Yul;Kim, Man;Lee, Kyu-Hwan;Yim, Seong-Bong;Lee, Jong-Il
    • Journal of the Korean institute of surface engineering
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    • v.43 no.1
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    • pp.1-6
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    • 2010
  • The effect of organic additives, 1-(3-sulfoproyl)-2-vinylpyridineium hydroxide (SVH) and thiourea (TU), on the precision copper electrodeposition was investigated with optical, electrochemical and x-ray diffraction techniques. It was found that SVH played a r ole as a n accelerator and TU as an i nhibitor during the electroreduction of cupric ions in acidic Cu electroplating solution. Through electrochemical measurements, TU showed more strong interaction with cupric ions than SVH and dominated overall Cu electroplating process when both additives were present in the solution. In the case of three dimensional Cu electrodeposition on the 20 ${\mu}m$-patterned Ni substrates, SVH controlled the upright growth of Cu electrodeposits and so determined its flatness, while TU prohibited the lateral spreading of Cu in the course of pulse-reverse pulse current adaptation. With microscopic observation, we obtained the optimum organic additives composition, that is, 100 ppm SVH and 200 ppm TU during the current pulsation.

Measurement of Voltage Transfer Curve in AC PDP (AC-PDP특성평가를 위한 전압전달곡선 계측에 관한 연구)

  • 손진부;이성현;김동현;김영대;조정수;박정후
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.05a
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    • pp.395-398
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    • 1999
  • In ac PDP(plasma Display Panel), the discharge characteristics is very important to display clear images. In this paper, we have studied the measurement of voltage transfer curves which show the discharge characteristics in AC PDP. The change of the effective wall capacitance during a discharge is also studied. These depend on lateral spreading of charge distribution and the strength of the discharge. As a parameter of the frequency, we observed the effects of the frequency in voltage transfer curves and in effective wall capacitance changes. As frequency increases, minimum sustain voltage and firing voltage decrease. In upper region of gap voltage the chance of the effective wall capacitance is independent of frequency.

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Beam models for continuous pipelines passing through liquefiable regions

  • Adil Yigit
    • Geomechanics and Engineering
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    • v.37 no.2
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    • pp.189-195
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    • 2024
  • Buried pipelines can be classified as continuous and segmented pipelines. These infrastructures can be damaged either by ground movement or by seismic wave propagation during an earthquake. Permanent ground deformations (PGD) include surface faulting, liquefaction-induced lateral spreading and landslide. Liquefaction is a major problem for both superstructures and infrastructures. Buyukcekmece lake zone, which is the studied region in this paper, is a liquefaction prone area located near the North Anatolian Fault Line. It is an active fault line in Turkey and a major earthquake with a magnitude of around 7.5 is expected in this investigated region in Istanbul. It is planned to be constructed a new 12" steel natural gas pipeline from one side of the lake to the other side. In this study, this case has been examined in terms of two different support conditions. Firstly, it has been defined as a beam in liquefied soil and has built-in supports at both ends. In the other approach, this case has been modeled as a beam in liquefied soil and has vertical elastic pinned supports at both ends. These models have been examined and some solution proposals have been produced according to the obtained results. In this study, based on this sample, it is aimed to determine the behaviors of buried continuous pipelines subject to liquefaction effects in terms of buoyancy.

Comparative Evaluation of Behavior Analysis of Rectangular Jet and Two-dimensional Jet (사각형제트와 2차원제트의 거동해석의 비교 평가)

  • Kwon, Seok Jae;Cho, Hong Yeon;Seo, Il Won
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.6B
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    • pp.641-649
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    • 2006
  • The behavior of a three-dimensional pure rectangular water jet with aspect ratio of 10 was experimentally investigated based on the results of the mean velocity field obtained by PIV. The saddle back distribution was observed in the lateral distribution along the major axis. The theoretical centerline velocity equation derived from the point source concept using the spreading rate for the axisymmetric jet was in good agreement with the measured centerline velocity and gave the division of the potential core region, two-dimensional region, and axisymmetric region. The range of the two-dimensional region divided by the criterion of the theoretical centerline velocity decay for the aspect ratio of 10 was observed to be smaller than that of the transition region. The applicability of the two-dimensional model to the behavior of the rectangular jet with low aspect ratio or the wastewater discharged from a multiport diffuser in the deep water of real ocean may result in significant error in the transition and axisymmetric regions after the two-dimensional region. In the two-dimensional region, the Gaussian constant tended to be conserved, and the spreading rate slightly decreased at the end of the two-dimensional region. The normalized turbulent intensity along the centerline of the jet initially abruptly increased and showed relatively higher intensity for higher Reynolds number.

Recovery of Covalently Linked Fatty Acid Monolayer on the Hair Surface Using Biomimetic Lipid (생체모사 지질을 이용한 모발 표면에 공유 결합된 지방산 단분자층의 회복)

  • Kim, Ei-Suk;Son, Seong-Kil;Lee, Cheon-Koo
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.38 no.2
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    • pp.139-145
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    • 2012
  • There is a unique type of fatty acid in the hair surface. 18-methyleicosanoic acid (18-MEA) is an unusual anteiso fatty acid covalently linked to the outermost surface of hair cuticle. A layer of 18-MEA is located in the upper ${\beta}$-layer of the CMC that is responsible for the low surface energy and low friction resistance of the hair's outer surface. The high mobility of 18-MEA molecule facilitates spreading of extraneous lipid by decreasing interfacial shear strength. In this study, we introduced N-hydroxyl succinimidyl ester functional group to the one end of C10 - 40 isoalkyl acid for regenerating hair surface with covalently bound fatty acid layer. The re-hydrophobicization of hair surface has been investigated by contact angle measurement. The inner moisture content of hair at different levels of humidity (40, 55, 70 %RH) was measured by electric moisture analyzer. Treatment with Hydroxysuccinimidyl C10 - 40 Isoalkyl Acidate (HCIA) was supposed to make hair surface smoother by filling the cracks between cuticles with covalently bound fatty acid monomolecular layer like cuticle glue. This glue effect was also confirmed with line profile of AFM images. Therefore, the moisture and structural components of inner hair were not easily flown out and the optimum moisture content could be kept constantly though the outside humidity level was changed. The lateral force microscopy (LFM) by using atomic force microscope showed that the friction force of hair surface treated with HCIA was decreased. It also showed the constantly sustained friction value even after shampooing repeated 15 times.

Dynamics of the River Plume (하천수 플룸 퍼짐의 동력학적 연구)

  • Yu, Hong-Sun;Lee, Jun;Shin, Jang-Ryong
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.6 no.4
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    • pp.413-420
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    • 1994
  • Dynamics of the river plume is a very complicated non-linear problem with the free boundary changing in time and space. Mixing with the ambient water through the boundary makes the problem more complicated. In this paper we reduced 3-dimensional problem into 1-dimensional one by using the integral analysis method. Basic equations have been integrated over the lateral and vertical variations. For these integrations we adopted the well-established assumption that the flow-axis component of plume velocity and the density difference of the plume with the ambient water have Gaussian distributions in directions which are perpendicular to the flow-axis of the plume. We also used the result of our previous study on the lateral spreading velocity of the plume derived under the same assumption. And entrainment was included as a mixing process. The resultant 1-dimensional equations were solved by Runge-Kutta numerical method. Consequently, comparatively easy method of numerical analysis is presented for the 3-dimensional river plume. The method can also be used for the analysis of the thermal plume of cooling water of power plants.

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Appropriate Block Level in Neurolytic Lumbar Sympathetic Ganglion Block (신경파괴적 요부교감신경절 차단의 적정 부위)

  • Kim, Hee-Jung;Lee, Cheol-Oh;Shin, Yang-Sik;Lee, Youn-Woo
    • The Korean Journal of Pain
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    • v.14 no.2
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    • pp.199-206
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    • 2001
  • Background: The lumbar sympathetic ganglia are variable in both position and numbers. The aim of this study was to detect the appropriate lumbar vertebral level where the lumbar sympathetic ganglia primarily aggregate. Methods: Forty patients comprising of hyperhidrosis (26 cases), complex regional pain syndrome (10 cases), peripheral artery occlusion disease (3 cases) and postherpetic neuralgia (1 case) underwent lumbar sympathetic block. We randomly selected one of two (L2 or L3) levels and the L4 level. The position of the needle tip and distribution of dye was verified by injection of a mixture of radio-opaque dye (1.5 ml) and 4% lidocaine (1.5 ml) and subsequently confirmed by L-spine anteroposterior and a lateral view X-ray. We considered the response positive when the skin temperature increased more than $1^{\circ}C$ in 5 min. Results: In general, the positive response ratio was greater when the needle tip located at the L2 or L4 level vice L3 and when the drug was distributed on the lower half of the L4 body and in the L4/5 intervertebral disc space. In a right side block, the positive response ratio was greater when the drug was distributed on the lower half of the L4 body and in the L4/5 intervertebral disc space, although in a left side block there was no significant difference seen between the levels. The complications of the neurolytic block were alcohol neuritis (7.5%) and hypoesthesia (5%) on the L1 or L2 dermatome. Conclusions: The best effect with least chance of complication may be induced by spreading the drug on the lower half of the L4 body and/or into the L4/5 intervertebral disc space by placing the needle tip on the L4 body.

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