• Title/Summary/Keyword: Trapezoid

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Experimental Study on R-410A Evaporation Heat Transfer Characteristics in Shell and Plate Heat Exchanger (셀 앤 플레이트 열 교환기에서의 R-410A 증발열전달에 관한 실험적 연구)

  • Kim In-Kwan;Kim Young-Soo;Park Jae-Hong
    • Journal of Advanced Marine Engineering and Technology
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    • v.29 no.1
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    • pp.49-59
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    • 2005
  • The evaporation heat transfer experiments are conducted with the shell and plate heat exchanger (S&PHE) without oil in the refrigerant loop using R-410A. An experimental refrigerant loop has been established to measure the evaporation heat transfer coefficient h. of R-410A in a vertical S&PHE. Two vertical counter flow channels were formed in the S&PHE by three plates haying a corrugated trapezoid shape of a $45^{\circ}C$ chevron angle. UP flow of the boiling R-410A in one channel receives heat from the hot down flow of water in the other channel The effects of the refrigerant mass flux. average heat flux. refrigerant saturation temperature and vapor qualify are explored in detail. Similar to the case of a plate heat exchanger. even at a very low Reynolds number, the flow in the S&PHE remains turbulent. The Present data shows that the evaporation heat transfer coefficients of R-410A increased with the vapor qualify. The results indicate a rise in the refrigerant mass flux caused an increase in the h.. Raising the imposed wall heat flux is found to slightly improve h., while h, is found to be lower at a higher refrigerant saturation temperature. Based on the present data. empirical correlation of the evaporation heat transfer coefficient is proposed.

Recognition of the Passport by Using Fuzzy Binarization and Enhanced Fuzzy Neural Networks

  • Kim, Kwang-Baek
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2003.09a
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    • pp.603-607
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    • 2003
  • The judgment of forged passports plays an important role in the immigration control system, for which the automatic and accurate processing is required because of the rapid increase of travelers. So, as the preprocessing phase for the judgment of forged passports, this paper proposed the novel method for the recognition of passport based on the fuzzy binarization and the fuzzy RBF neural network newly proposed. first, for the extraction of individual codes being recognized, the paper extracts code sequence blocks including individual codes by applying the Sobel masking, the horizontal smearing and the contour tracking algorithm in turn to the passport image, binarizes the extracted blocks by using the fuzzy binarization based on the membership function of trapezoid type, and, as the last step, recovers and extracts individual codes from the binarized areas by applying the CDM masking and the vertical smearing. Next, the paper proposed the enhanced fuzzy RBF neural network that adapts the enhanced fuzzy ART network to the middle layer and applied to the recognition of individual codes. The results of the experiment for performance evaluation on the real passport images showed that the proposed method in the paper has the improved performance in the recognition of passport.

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Understanding the Construction of Chang-ui in the Middle Chosun Dynasty -Through the Process of Reconstructing Chang-ui Excavated from General Parks Tomb- (조선중기 창의구성의 이해 -전 박장군묘 청색무명겹창의의 재현을 통하여-)

  • 장인우
    • Journal of the Korean Society of Clothing and Textiles
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    • v.25 no.3
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    • pp.548-559
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    • 2001
  • This study is to understand Chang-ui construction of the middle Chosun Dynasty through the reconstruction of the blue Chang-ui which was excavated from General Parks tomb. The followings are the results of this study. There are 4 styles in excavated Chang-ui of middle Chosun Dynasty: Two styles seem to belong to the early 17th Century and the other, the late 17th century. The former is classified into 2 styles by the gender of the wearer, the latter is also classified into 2 styles by etiquette of clothing. We can assume that Chang-ui excavated from General Parks tomb was the womans clothing in early 17th century. This Chang-ui(II) differs from other Chang-ui(I) at two points. One is the construction of the trapezoid and triangle gussets on the side seam of clothing. The other is the construction of the narrow width of clothing(23cm). We have found that these two gussets could improve the active aspect of clothing and save materials. It is identified that the green tone was faded from the blue color of Chang-ui according to the calculation of the L*a*b.

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Simulation of Microlens Array for the Improvement of Outcoupled Efficiency of Organic Light-emitting Diodes (유기 발광 소자의 광추출 효율 향상을 위한 마이크로 렌즈 어레이의 시뮬레이션)

  • Hwang, Deok Hyeon;Kim, Hye Sook;Lee, Won Jae;Lee, Seunghun;Kim, Tae Wan
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.26 no.10
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    • pp.745-753
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    • 2013
  • Performance of organic light-emitting diodes incorporating microlens array was simulated using a Light Tools software. Use of microlens array can help the light to escape out of the device. We simulated a reference device that is consisted of reflection layer, emissive layer, and flat transparent substrate. And in this reference device, outcoupled efficiency of 22% was obtained. Several shapes of microlens were applied such as hemisphere, trapezoid, cone, and rectangular parallelepiped. The results showed the improvement of outcoupled efficiency of the device with microlens compared to that of the reference one. And from the analyses of the simulated data, the obtained appropriate shape of microlens is hemisphere, and the improvement of the device with hemispherical lens is 57% higher than that of the reference one.

An Experimental Study on Pressure drop Characteristics in Plate and Shell Heat Exchanger (Plate and Shell 열교환기내의 R-22 응축압력강하 특성에 관한 실험적 연구)

  • 이기백;서무교;박재홍;김영수
    • Journal of Advanced Marine Engineering and Technology
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    • v.25 no.6
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    • pp.1220-1227
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    • 2001
  • The condensation pressure drop fur refrigerant R-22 flowing in the plate and shell heat exchanger were investigated experimentally in this study. Two vertical counterflow channels were formed in the exchanger by three plates of commercial geometry with a corrugated trapezoid shape of a chevron angel of $45^{\circ}$. The condensing R-22 flowing down in one channel exchanges heat with the cold water flowing up in the other channel. The effects of the mean vapor quality, mass flux, average imposed heat flux and system pressure of R-22 on the pressure drop were explored in detail. The quality change of R-22 between the inlet and outlet of the refrigerant channel ranges from 0.03 to 0.05. The present data showed that pressure drop increases with the vapor quality. At a higher mass flux, pressure drop is higher for the entire range of the vapor quality. Also, a rise in the average imposed heat flux causes an slight increase in the Pressure drop. Finally, at a higher system pressure the pressure drop is found to be slightly lower. Correlation is also provided for the measured pressure drops in terms of the friction factor.

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Experimental Study on R-l34a Condensation Beat Transfer Characteristics in Plate and Shell Heat Exchanger (판각형 열교환기내의 R-134a 응축열전달 특성에 관한 실험적 연구)

  • 이기백;박재홍;서무교;이희웅;김영수
    • Journal of Advanced Marine Engineering and Technology
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    • v.27 no.1
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    • pp.108-116
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    • 2003
  • In this paper, the experimental results of condensation heat transfer were reported for the plate and shell heat exchangers(P&SHE) using R-l34a. An experimental refrigerant loop has been established to measure the condensation heat transfer coefficient of R-l34a in a vertical P&SHE. Two vertical counter flow channels were formed in the P&SHE by three plates of geometry with a corrugated trapezoid shape of a chevron angle of 45$^{\circ}$. Downflow of the condensing R-l34a in one channel releases heat to the cold up flow of water in the other channel. The effect of the refrigerant mass flux, average heat flux, system pressure and vapor quality of R-l34a on the measured data were explored in detail. The results indicate that at a higher vapor quality the condensation heat transfer coefficients are significantly higher. Condensation heat transfer coefficients were increased when the refrigerant mass flux was increased. A rise in the average heat flux causes an slight increase in the hr. Finally, at a higher system pressure the hr is found to be lower. Correlation is also provided for the measured heat transfer coefficients in terms of the Nusselt number.

Passport Recognition using Fuzzy Binarization and Enhanced Fuzzy RBF Network

  • Kim, Kwang-Baek
    • Journal of the Korean Institute of Intelligent Systems
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    • v.14 no.2
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    • pp.222-227
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    • 2004
  • Today, an automatic and accurate processing using computer is essential because of the rapid increase of travelers. The determination of forged passports plays an important role in the immigration control system. Hence, as the preprocessing phase for the determination of forged passports, this paper proposes a novel method for the recognition of passports based on the fuzzy binarization and the fuzzy RBF network. First, for the extraction of individual codes for recognizing, this paper targets code sequence blocks including individual codes by applying Sobel masking, horizontal smearing and a contour tracking algorithm on the passport image. Then the proposed method binarizes the extracted blocks using fuzzy binarization based on the trapezoid type membership function. Then, as the last step, individual codes are recovered and extracted from the binarized areas by applying CDM masking and vertical smearing. This paper also proposes an enhanced fuzzy RBF network that adapts the enhanced fuzzy ART network for the middle layer. This network is applied to the recognition of individual codes. The results of the experiments for performance evaluation on the real passport images showed that the proposed method has the better performance compared with other approaches.

Improvement of Dynamic Characteristic of Large-Areal Planar Stage Using Induction Principle (인덕션 방식을 이용한 평면 스테이지의 동특성 개선)

  • Jung, Kwang-Suk;Park, Jun-Kyu;Kim, Hyo-Jun
    • Journal of Institute of Control, Robotics and Systems
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    • v.15 no.7
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    • pp.675-682
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    • 2009
  • Instead of direct driving like BLDC, the induction principle is adopted as a driving one for planar stage. The stage composed of four linear induction motors put in square type is activated by two-axial forces; low-frequency attractive force and thrust force of the linear induction motors. Here, the modified vector control whose new inputs are q-axis current and dc current biased to three phase current instead of d-axis current or flux current is applied extensively to overall motion of the stage. For the developed system, the precision step test and the constant velocity test are tried to guarantee its feasibility for TFT-LCD pattern inspection. However, to exclude a discontinuity due to phase shift and minimize a force ripple synchronized with the command frequency, the initial system is revised to the antagonistic structure over the full degree of freedom. Concretely describing, the porous air bearings guide an air-gapping of the stage up and down and a pair of liner induction motors instead of single motor are activated in the opposite direction each other. The performances of the above systems are compared from trapezoid tracking test and sinusoidal test.

Experimental Study on R-22 Condensation Heat Transfer Characteristic in Plate and Shell Heat Exchanger (Plate and Shell 열교환기 내의 R-22 응축열전달 특성에 관한 실험적 연구)

  • Seo, Mu-Gyo;Park, Jae-Hong;Kim, Yeong-Su
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.25 no.6
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    • pp.860-867
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    • 2001
  • In this study, condensation heat transfer experiments were conducted with plate and shell heat exchangers(P&SHE) using R-22. An experimental refrigerant loop has been established to measure the condensation heat transfer coefficient of R-22 in a vertical P&SHE. Two vertical counter flow channels were formed in the P&SHE by three plates of geometry with a corrugated trapezoid shape of a chevron angle of 45°. Downflow of the condensing R-22 in one channel releases heat to the cold upflow of water in the other channel. The effect of the refrigerant mass flux, average heat flux, system pressure and vapor quality of R-22 on the measured data were explored in detail. The results indicate that at a higher vapor quality the condensation heat transfer coefficients are significantly higher. A rise in the refrigerant mass flux causes an increase in the h(sub)r. Also, a rise in the average heat flux causes an increase in the h(sub)r. Finally, at a higher system pressure the h(sub)r is found to be slightly lower. Correlation is also provided for the measured heat transfer coefficients in terms of the Nusselt number.

A Study on the Piazza Plan of Basilica S. Pietro (산 피에트로 교회의 광장계획에 관한 연구)

  • Kim, Seok-Man
    • Journal of architectural history
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    • v.14 no.1 s.41
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    • pp.7-19
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    • 2005
  • The purpose of this paper is the study on the piazza plan of basilica S. Pietro. The results of study are as follows: 1. The piazza of the basilica S. Pietro was planned in relation to building-piazza-symbol of interior piazza-street as city planning characteristic of Baroque and architectural characteristic of elliptical piazza form. 2. The function of piazza of basilica S. Pietro was planned for religious meeting of a grand scale than a piazza for the common run of people. 3. In general, the disposition, ground, elevation and section plan of the piazza of basilica S. Pietro was planned by principle of spatial and formal composition, according to axis, symmetry, proportion, division and contrast. 4. The location, scale, shape of piazza for disposition and ground plan of the piazza of basilica S. Pietro was basically decided by not only elements of Basilica building, Vatican Palace, Street and Walls of surroundings with axis of the Basilica building, but Fountain and Obelisk as existing constituent elements. 5. The elevation of the piazza of basilica S. Pietro was composed of boundary that was enclosed from wall of trapezoid piazza and gallery of elliptical piazza with equal height as symmetry. And the section plan was planned to approach into the Basilica through slope and stairs of gentle angle, utilizing of existing land form.

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