• Title/Summary/Keyword: Glass tube

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Thermal Performance Variations of Glass Evacuated Tube Solar Collectors Depending on the Absorber Shape and the Incidence Angle of Solar Ray (흡수관 형상과 일사 각도에 따른 진공관형 태양열 집열기의 성능 변화)

  • Kim Yong;Seo Tae-Beom;Kang Yong-Heack
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.17 no.7
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    • pp.659-668
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    • 2005
  • The thermal performances of glass evacuated tube solar collectors are numerically investigated. Four different shapes of solar collectors are considered and the performances of these solar collectors are numerically investigated. Dealing with only collecting tube, the effects of not only the shape of the absorber tube but also the incidence angle of solar irradiation on the thermal performance of the collector are studied because the energy obtained by the absorber can be varied according to the incidence angle of solar radiation. However, the solar irradiation consists of the beam radiation as well as the diffuse radiation. Also, in actual system, the interference of solar irradiation and heat transfer interaction between the tubes should be considered. Therefore, this study considered these effects is carried out experimentally and numerically. The accuracy of the numerical model is verified by experiments. The result shows that the thermal performance of the absorber used a plate fin and U-tube is about $25\%$ better than those of the other models.

Investigation of Energy Absorption Property of Glass/Epoxy Composite Tubes with Bevel and Tulip Triggers (베벨 및 튤립 트리거를 갖는 유리섬유 복합소재 튜브의 에너지 흡수특성 평가)

  • Kim, Jung Seok
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.26 no.4
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    • pp.395-401
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    • 2017
  • Energy absorption capabilities and failure modes of circular tubes made of glass/epoxy with two trigger mechanisms were evaluated. Three types of glass/epoxy tubes were fabricated using a hand lay-up method with unidirectional and woven fabric prepregs tapes, and a filament winding method. The one end of the fabricated tubes was machined for the bevel trigger and tulip trigger. Then, crush tests were conducted at 10 mm/min loading speed, wherein the glass/epoxy tubes were crushed by a brittle fracturing mode combined with fragmentation and lamina-splaying modes. The UD glass/epoxy tubes with a bevel trigger and the filament winded tubes with a tulip trigger showed the maximum and minimum specific energy absorptions, respectively, with a difference of 9.3%. The tube with a tulip trigger exhibited a maximum reduction of 5.7% in the initial peak load; the tube with a bevel trigger showed a maximum increase of 2.9% in the specific energy absorption.

Immobilized ${\beta}-Cyclodextrin$ as a Simple and Recyclable Method for Cholesterol Removal in Milk

  • Kwak, H.-S.;Kim, S.-H.;Kim, J.-H.;Choi, H.-J.;Kang, J.
    • Archives of Pharmacal Research
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    • v.27 no.8
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    • pp.873-877
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    • 2004
  • This study was designed to determine the optimum conditions of three different factors (mixing time, mixing temperature, and tube size) in reduction of cholesterol in milk using immobilized $\beta$-CD beads. Immobilized $\beta$-CD glass beads were prepared at different conditions of silaniza-tion and $\beta$-CD immobilization reactions. In result, the glass beads (diameter 1 mm) at 20 mM 3-isocyanatopropyltriethoxysilane and 30 mM $\beta$-CD without base showed the highest choles-terol removal rate as 41%. Using above immobilized $\beta$-CD glass beads, the cholesterol removal rate was 40.2% with 6 h of mixing time in 7 mm diameter tube at $10^{\circ}C$. After choles-terol removal from milk, the glass beads were washed for cholesterol dissociation and reused. In recycling study, the cholesterol removal rate was 41%, which was mostly same as that using new glass beads. These results indicated that cholesterol removal rate was about 40% with $\beta$-CD immobilized glass beads, however, the recycling efficiency was almost 100%.

Comparison of Dose Measurement of Glass Dose Meter, Semiconductor Dose Meter, and Area Dose Meter in Diagnostic X-ray Energy (진단영역 X선 에너지에서 유리선량계, 반도체선량계, 면적선량계의 선량 실측 비교)

  • Son, Jin-Hyun
    • Journal of radiological science and technology
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    • v.42 no.6
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    • pp.483-489
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    • 2019
  • This paper obtained and compared these dose values by setting and comparing the X-ray imaging conditions (tube voltage 60 kVp, 70 kVp, 80 kVp, tube current 10 mAs, 16 mAs and X-ray field size are 10 × 10 cm, 15 × 15 cm). Each dose value was measure 10 times and represented as an average value. The purpose of this experiment is to serve as a reference for the X-ray exposure of diagnostic areas according to the type of dosimeter and to help with another dose measurement. The results of the experiment showed very little difference between the glass dosimeter(GD) and semiconductor dosimeter values due to changes in tube voltage of 60, 70, 80 kVp, regardless of field sized, but for dose area product(DAP), the difference in dose value was significant according to field size.

The measurement of $H_2O_2$ Concentration and Simulation of Electric Field Distribution at Dielectric Tube of one Layer with Globular Dielectric in Water (구형 유전체비드를 가지는 단층절연방전관의 $H_2O_2$ 농도 측정 및 전계분포시뮬레이션)

  • Park, Hong-Jae;Park, Jae-Youn;Lee, Dong-Hoon;Koh, Hee-Seog;Lee, Hyun-Su
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.08a
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    • pp.40-43
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    • 2003
  • In this paper, the electric field distribution in dielectric tube with one layer and spherical dielectric(glass) in water was simulated. The reactor was made up of the spherical dielectric that is diameter : 3.0[mm], glass(${\varepsilon}_r$:5) and one glass plate of thickness(2[mm]), ${\varepsilon}_r$(5) as electrode. The discharge gap was 8[mm). Toget more strong electric field, the dielectric constant should be higher comparatively. Using the spherical dielectric for water discharge in dielectric tube, the location of equipotential line was shifting from the interior to the exterior. At real water discharge experimental, $H_2O_2$ was measured higher generated $H_2O_2$ in water at condition of water rate(1[l/min]) and injector than condition of non-injector or 2-3[l/min])

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A study on reducing temperature rise of twin-glass evacuated tube solar collector during summer time (이중진공관형 태양열 집열기의 하절기 과열 방지에 대한 연구)

  • Bai, Sang-Eun;Bai, Cheol-Ho;Nam, Hyun-Kyu;Shin, Ki-Yeol;Yoo, In-Ho
    • Journal of the Korean Solar Energy Society
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    • v.33 no.3
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    • pp.36-41
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    • 2013
  • The reflection plate in twin-glass evacuated tube solar collector is controlled to reduce the overheat during the summer time. The sliding type and folding types are suggested and tested. The sliding type changes the plate angle and the folding type changes the opening angle of the reflection plate. By scattering the focus of the reflected radiation from the reflection plate, the temperature rise of the working fluid can be reduced. The sliding type shows the best results in overheat reduction. When solar radiation is 900 $W/m^2$, the temperature rise in one sliding type collector is reduced about $2^{\circ}C$ compared to that of the normal solar collector. When this method is applied to seven series-collectors in the field, the reduction of temperature rise during the summer time should be significant.

An Experimental Study for Apply Solar System on Thermal Performance of Heat Pipe Type Solar Collector using a Glass Concentric Evacuated Tube in a Summer (하절기 태양열 시스템 적용을 위한 이중진공관 히트파이프형 집열기 열성능의 실험적 연구)

  • Kang, C.H.;Bae, C.H.;Hong, J.K.;Suh, J.S.
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.1646-1651
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    • 2004
  • This paper has been carried out to find the thermal efficiency and operating characteristics of heatpipe type solar collector using a glass concentric evacuated tube(CETC) during summer. In an experiment the flow rate of water in collector are 1.5l/min. Collector efficiency is $50{\sim}60%$ during time. The solar radiation appeared in a clear day is efficiency high. Efficiency curve fitted first order polynomial show that $F_{R}$$({\tau}{\alpha})$ and $F_{R}U_{L}$=1.316 is 0.601 and 1.316 respectively.

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Preparation of Porous PLGA Microfibers Using Gelatin Porogen Based on a Glass Capillary Device (젤라틴 기공유도물질과 유리모세관 장치를 이용한 다공성 PLGA 미세섬유의 제조)

  • Kim, Chul Min;Kim, Gyu Man
    • Journal of the Korean Society for Precision Engineering
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    • v.33 no.1
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    • pp.63-67
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    • 2016
  • We present a method of fabricating poly (lactic-co-glycolic acid) (PLGA) porous microfibers using a pore template. PLGA microfibers were synthesized using a glass capillary tube in a poly-(dimethylsiloxane) (PDMS) microfluidic chip. Gelatin solution was used as a porous template to prepare pores in microfibers. Two phases of PLGA solutions in different solvents-DMSO (dimethyl sulfoxide) and DCM (dichloromethane)-were used to control the porosity and strength of the porous microfibers. The porosity of the PLGA microfibers differed depending on the ratio of flow rates in the two phases. The porous structure was formed in a spiral shape on the microfiber. The porous structure of the microfiber is expected to improve transfer of oxygen and nutrients, which is important for cell viability in tissue engineering.

Bending Performance Evaluation of Aluminum-Composite Hybrid Square Tube Beams (알루미늄-복합재료 혼성 사각관 보의 굽힘 성능평가)

  • Lee, Sung-Hyuk;Choi, Nak-Sam
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2005.04a
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    • pp.76-79
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    • 2005
  • Bending deformation and energy absorption characteristics of aluminum-composite hybrid tube beams have been analyzed for improvement in the bending performance of aluminum space frame by using experimental tests combined with theoretical and finite element analyses. Hybrid tube beams composed of glass fabric/epoxy layer wrapped around on aluminum tube were made in autoclave with the recommended curing cycle. Basic properties of aluminum material used for initial input data of the finite element simulation and theoretical analysis were obtained from the true stress-true strain curve of specimen which had bean extracted from the Al tube beam. A modified theoretical model was developed to predict the resistance to the collapse of hybrid tube beams subjected to a bending load. Theoretical moment-rotation angle curves of hybrid tube beams were in good agreement with experimental ones, which was comparable to the results obtained from finite element simulation. Hybrid tube beams strengthened by composite layer on the whole web and flange showed an excellent bending strength and energy absorption capability.

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