• Title, Summary, Keyword: Point-Mass

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Water Droplet Ejection Characteristics of a Wet Porous Point-Plate Airgap (다공성 수침-평판전극간의 수적 방출 특성)

  • Jung, Jae-Seung;Lee, Woo-Seok;Moon, Jae-Duk
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.10
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    • pp.2005-2010
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    • 2009
  • Water droplet ejection characteristics of a point-to-plate airgap, with a wet porous point as a corona electrode, has been investigated. And the water droplet traces, charge, mass and number were measured experimentally. More particles are observed with wet porous point than metal point because the corona-discharging wet porous point can eject a number of water droplets. The water droplets ejected from the positive-corona-discharging wet porous point showed very fine traces as compared with those from the negative-corona-discharging wet porous point. Moreover, the water droplets ejected from the AC-corona-discharging wet porous point showed granular-like larger traces. It was shown that the weak corona discharge can eject smaller water droplets with larger ratio of mass-to-charge than the intense corona discharge.

Study on the Equilibrium Point of Heat and Mass Transfer between Liquid Desiccant and Humid Air with in the Solar Air Conditioning System

  • Sukmaji, I.C.;Rahmanto, H.;Agung, B.;Choi, K.H.;Kim, J.R.
    • 한국태양에너지학회:학술대회논문집
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    • pp.161-167
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    • 2009
  • The liquid solar air conditioning system is introduced as an alternative solution to control air condition and to save electrical energy consumption. The heat and mass transfer performances of dehumidifier/regenerator in liquid solar air conditioning system are influenced by air and desiccant condition. The application of this system, the thermal energy from the sun and inlet air are unable to control, but operation parameter of other components such as pump, fan and sensible cooling unit are able to control. The equilibrium point of heat and mass transfer are the liquid desiccant and inlet air conditions, where, the heat and mass are not transferred between the liquid desiccant and vapor air. By knowing equilibrium point of heat and mass transfer, the suitable optimal desiccant conditions for certain air condition are funded. This present experiment study is investigated the equilibrium point heat and mass transfer in various air and desiccant temperature. The benefit of equilibrium point heat and mass transfer will be helpful in choose and design proper component to optimize electrical energy consumption.

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Development of Thermal Mass Flow Meter (열전달 질량유량계 개발)

  • Chi, Daesung
    • 유체기계공업학회:학술대회논문집
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    • pp.118-122
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    • 1999
  • Thermal mass flow meter was developed using principle of convective heat transfer. The advantage of thermal mass flow meter is measuring mass flow directly, therefore, it is not required to use densitometer or temperature/pressure and DP gages. The final accuracy of this thermal mass flow meter is $\pm1.0{\%}$ or better, reproducibility is $\pm0.2{\%}$, and the response time is 600 ms. The thermal mass flow meter was developed from a single point to multi-points (maximum is 9 points), and the number of points is determined according to desired accuracy and size of piping/duct. Since this thermal mass flow meter adopted microprocessor based design, it is intrinsically accurate, self-error detectable, and has self-diagnosis function. The applications of this thermal mass flow meter are for measurement and control of HVAC air flow, other gas flow, and liquid flow.

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A Study on the Mass Collection Efficiency in Collector Step of Electrostatic Precipitator by Physical Gas Characterization (전기집진장치에서 가스의 물리적인 특성에 따른 포집구역내의 입자포집율 연구)

  • Ha, Sang-An;Im, Gyeong-Taek;Sin, Nam-Cheol
    • Journal of Environmental Science International
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    • v.7 no.1
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    • pp.36-40
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    • 1998
  • This study was carried out to investigate the collection Efficiency of mass in collector step at the different of physical gas characterization. This work has focused on the dependence of the collection efficiency of mass in the collector zone of a two-stage set up field with gas temperature T and the dew point tmeperature. To identify the dependence of the mass collection efficiency on the Bounded plate of the collector zone MP.k by the spectre electric resistance of dust $p_e$. and the relative humidify ${\varphi}$, 20 at- tempts have been made with three different gas temperature ($50{\circ}C, 80{\circ}C, 110{\circ}C$) at different dew point. At the specific electric resistance of dust $p_e$=$10^6{\Omega}m$ which relative humidity corresponds to $\phi$ > 15%, a easy rise of the sounded plate secluded dust mass share was measured atwain. As the result of the higher cohesion imprisonment power due to the adsorbtion of particle, the rinse of the relative humidity developed on the particle surface. Therefore, the collection efficiency of mass was not predominant the high temperature T in the collector zone, neither was the pecific ellectric resistance of dust dependent.

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Technical Development for Extraction of Discontinuities in Rock Mass Using LiDAR (LiDAR를 이용한 암반 불연속면 추출 기술의 개발 현황)

  • Lee, Hyeon-woo;Kim, Byung-ryeol;Choi, Sung-oong
    • Tunnel and Underground Space
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    • v.31 no.1
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    • pp.10-24
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    • 2021
  • Rock mass classification for construction of underground facilities is essential to secure their stabilities. Therefore, the reliable values for rock mass classification from the precise information on rock discontinuities are most important factors, because rock mass discontinuities can affect exclusively on the physical and mechanical properties of rock mass. The conventional classification operation for rock mass has been usually performed by hand mapping. However, there have been many issues for its precision and reliability; for instance, in large-scale survey area for regional geological survey, or rock mass classification operation by non-professional engineers. For these reasons, automated rock mass classification using LiDAR becomes popular for obtaining the quick and precise information. But there are several suggested algorithms for analyzing the rock mass discontinuities from point cloud data by LiDAR scanning, and it is known that the different algorithm gives usually different solution. Also, it is not simple to obtain the exact same value to hand mapping. In this paper, several discontinuity extract algorithms have been explained, and their processes for extracting rock mass discontinuities have been simulated for real rock bench. The application process for several algorithms is anticipated to be a good reference for future researches on extracting rock mass discontinuities from digital point cloud data by laser scanner, such as LiDAR.

Exploring Case Study on Mass Customization of Domestic Company (국내 기업의 대량 맞춤화 사례연구)

  • Shin, Hyun-Am;Jeon, Ho-Ki;Lee, Won-Jun;Kang, Youn-Jung
    • Journal of Digital Convergence
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    • v.10 no.6
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    • pp.111-131
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    • 2012
  • Mass Customization combines the advantages of mass production and customization. Mass customization has been praised as an innovative approach that would result in changes in business paradigm. However, there is no consensus on the concept of mass customization, but only a generally accepted framework exists to explain successful practices. Prior cases in mass customization are those of the small-medium sized or Internet-based companies. We in this paper explore the mass customization cases of market-leading manufacturers. Although those traditional organizations may be not for swift change, the cases of those companies are important because they target mass markets. Lampel and Mintzberg[35] proposed a continuum of strategies ranging from pure standardization to pure customization. This study investigates mass customization strategies of three companies. In this paper, the cases of cosmetics and sports shoe can be described as tailored customization, and the household appliances case can be classified as customized standardization. These three cases are compared with each other from the customers' decoupling point. Findings and implications of this research are discussed.

A Simple Method of Vibration Analysis of Laminated Composite Plates Under Axial Loadings and with Attached Point Masses (축하중과 첨가질량이 작용하는 적층복합판의 진동해석)

  • Lee, Bong-hak;Kim, Kyeong-jin;Won, Chi-moon;Sung, Ki-tae
    • Journal of Industrial Technology
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    • v.15
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    • pp.169-174
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    • 1995
  • A method of calculating the natural frequency corresponding to the first mode of vibration of beams and tower structures, with irregular cross-sections and with arbitrary boundary conditions was developed and reported by D. H. Kim in 1974. IN this paper, the result of application of this method to the laminated plates with axial forces and with attached point mass/masses is presented. Both $N_x$ and $N_y$ forces are considered. The solution for the laminated plates with arbitrary boundary conditions and irregular section can be obtained by simply obtaining the deflection influence coefficients by any method. The effect of neglecting the mass of the plates on the natural frequency, as the ratio of the point mass/masses to the plate mass increases, is thoroughly studied. The influence of $N_x$ and $N_y$ is also carefully investigated.

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ON THE PHYSICAL BASIS OF THE TULLY-FISHER RELATION

  • RHEE MYUNG-HYUN
    • Journal of The Korean Astronomical Society
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    • v.37 no.1
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    • pp.15-39
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    • 2004
  • We analyse the results of mass models derived from the HI rotation! curves of spiral galaxies and find that the slope of the luminous mass-circular velocity relation is close to 4. The luminous mass-circular velocity relation with a slope of about 4 can be explained by an anti-correlation between the mass surface density of luminous matter and the mass ratio of the dark and luminous components. We also argue that the conspiracy between luminous and dark matter exists in a local sense (producing a flat or smooth rotation curve) and in a global sense (affecting the mass ratio of the dark and luminous matter), maintaining the luminous mass-circular velocity relation with a slope of about 4. We therefore propose that the physical basis of the Tully-Fisher relation lies in the luminous mass-circular velocity relation. While the slope of the luminous mass-circular velocity relation is fairly well defined regardless of the dark matter contribution, the zero-point of the relation is still to be determined. The determination of the slope of the Tully-Fisher relation needs one more step: the mean trend of the luminosity-luminous mass relation determines the overall shape (slope) of the Tully-Fisher relation. The key parameter needed to determine the zero-point of the luminous mass-circular velocity relation and the slope of the Tully-Fisher relation obviously is the luminous mass-to-light ratio.

SUBNORMAL WEIGHTED SHIFTS WHOSE MOMENT MEASURES HAVE POSITIVE MASS AT THE ORIGIN

  • Lee, Mi Ryeong;Kim, Kyung Mi
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.16 no.4
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    • pp.217-223
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    • 2012
  • In this note we examine the effects on subnormality of adding a new weight or changing some weights for a given subnormal weighted shift. We consider a subnormal weighted shift with a positive point mass at the origin by means of continuous functions. Finally, we introduce some methods for evaluating point mass at the origin about moment measures associated with weighted shifts.

An Experimental Study on the Characteristics of Temperature Distribution in Internal Space of a Tube for the Formal Change of Counterflow Type Vortex Tube (대향류형 보텍스 튜브의 노즐형상 변화011 따른 튜브 내부의 온도분포에 관한 실험적 연구)

  • 황승식
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.4
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    • pp.69-76
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    • 2002
  • The aim of this study is to provide fundamental informations that make it possible to use a cool stream and a hot stream simultaneously. We changed the pressure of compressed air that flows into a tube, the inner diameter of orifice that a cold stream exits, and the mass flow rate ratio. And in each case, we measured the temperature of a cold stream and a hot stream in each exit of a tube. Also we measured the axial and the radial temperature distribution in internal spare of a tube. From the study, fellowing conclusive remarks 7an be made. First, As the number of nozzles increase, separation point move into the hot exit. Second, When we use guide vane type nozzle, the axial temperature distribution constant over the 0.75 of air mass flow rate radio. Third, When we use Spiral type nozzle, axial and radial temperature distribution in the inner space is higher than another nozzle. Fourth, Axial and radial temperature distribution in the inner space vortex-tube is determined by separation point. And separation point is moved by changing of air mass flow rate ratio. At last, A heating apparatus is possible far vortex-tube to use.