• Title/Summary/Keyword: Rectangular groove

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Development of Optimum Grip System in Developing Design Tensile Strength of GFRP Rebars (GFRP 보강근의 설계 인장강도 발현을 위한 적정 그립시스템 개발)

  • You Young-Chan;Park Ji-Sun;You Young-Jun;Park Young-Hwan;Kim Keung-Hwan
    • Journal of the Korea Concrete Institute
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    • v.17 no.6 s.90
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    • pp.947-953
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    • 2005
  • Previous test results showed that the current ASTM(American Standard for Testing and Materials) grip adapter for GFRP(Glass Fiber Reinforced Polymer) rebar was not fully successful in developing the design tensile strength of GFRP rebars with reasonable accuracy. It is because the current ASTM grip adapter which is composed of a pair of rectangular metal blocks of which inner faces are grooved along the longitudinal direction does not take into account the various geometric characteristics of GFRP rebar such as surface treatment, shape of bar cross section as well as physical characteristics such as poisson effect, elastic modulus in the transverse direction and so on. The objective of this paper is to provide how to proportion the optimum diameter of inner groove in ASTM grip adapter to develop design tensile strength of GFRP rebar. The proportioning of inner groove in ASTM grip adapter is based on the force equilibrium of GFRP rebar between tensile capacity and minimum frictional resistance required along the grip adapter. The frictional resistance of grip adapter is calculated based on the compressive strain compatibility in radial direction induced by the difference between diameter of GFRP rebar and inner groove In ASTM grip. All testing procedures were made according to the CSA S806-02 recommendations. From the preliminary test results on round-type GFRP rebars, it was found that maximum tensile loads acquired under the same testing conditions is highly affected by the diameter of inner groove in ASTM grip adapter. The grip adapter with specific dimension proportioned by proposed method recorded the highest tensile strength among them.

A Study on the Load Characteristics of a Swash Plate Piston Pump Holder (Cradle) with Grooves Considering the Squeeze Effect (스퀴즈 효과를 고려한 사판식 피스톤 펌프 홀더의 그루브 유무에 따른 부하특성에 대한 연구)

  • Ju, Gyeong Jin;Seol, Sang Suk;Kim, Yong Gil;Kim, Soo Tae
    • Journal of Drive and Control
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    • v.17 no.1
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    • pp.21-26
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    • 2020
  • The load characteristics of a piston pump holder due to the squeeze effect are influenced by the surface shape and gap thickness of the holder (cradle). Therefore, the pressure distribution and the load capacity of the piston pump holder due to the squeeze effect are studied by using the CFD software and the surface shape and gap thickness of the piston pump holder are considered. In order to verify the accuracy of numerical results, the load capacities of a circular plate holder are numerically studied, and the accuracy of numerical results is verified by comparing with the theoretical results. Also, the pressure distribution and load capacity of the rectangular plate holder of a piston pump are obtained by using the CFD software. The results show that the load capacity of the square plate holder with grooves is slightly higher at a low gap thickness, but the effects of the number and arrangement of grooves on the load capacity of the holder are weak. We conclude that the load capacity and the maximum pressure are slightly affected due to the existence of grooves on the holder surface, and the fluid storing effect of the holder surface grooves during the operation is likely to prevent the dry-sticking phenomenon.

A Review on The Korean Grooved Adze (유구석부 재검토)

  • Ro Hyuk-Jin
    • KOMUNHWA
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    • no.57
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    • pp.3-24
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    • 2001
  • In terms of Typology, Korean Grooved Adzes are mainly grouped into two major types with some variations. Type 1 is characterized by such basic attributes as slant edge; trapezoidal groove; and rectangular or trapezoidal cross-section of a body. Whereas, T

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Development of the Structure for Enhancing Capillary Force of the Thin Flat Heat Pipe Based on Extrusion Fabrication (압출형 박판 히트파이프의 모세관력 향상을 위한 구조 개발)

  • Moon, Seok Hwan;Park, Yoon Woo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.40 no.11
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    • pp.755-759
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    • 2016
  • The use of heat pipes in the electronic telecommunication field is increasing. Among the various types of heat pipes, the thin flat heat pipe has relatively high applicability compared with the circular heat pipe in the electronic packaging application. The thin flat heat pipe based on extrusion fabrication has a simple capillary wick structure consisting of rectangular cross sectional grooves on the inner wall of the pipe. Although the groove serves as a simple capillary wick, and many such grooves are provided on the inner wall, it is difficult for the grooves to realize a sufficiently high capillary force. In the present study, a thin flat heat pipe with a wire bundle was developed to overcome the drawback of poor capillary force in the thin flat heat pipe with grooves, and was evaluated by conducting tests. In the performance test, the thin flat heat pipe with the wire bundle showed a lower thermal resistance of approximately 3.4 times, and a higher heat transfer rate of approximately 3.8 times with respect to the thin flat heat pipe with grooves as the capillary wick respectively. The possibility of using the wire bundle as a capillary wick in the heat pipe was validated in the present study; further study for commercializing this concept will be taken up in the future.

Study on the Radula of Korean Marine Gastropods (한국산 해산 권패류 치설의 형태에 관한 연구)

  • KANG Pil Ae
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.9 no.1
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    • pp.25-34
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    • 1976
  • The purpose of the present study on the radula of Korean marine gastropods is to determine the systematic position of the species by the radula features. The radula features of 9 Families based on the observation of specimens consisting of 31 species are described briefly as follows. 1. Naticidae; Radula formula 2-1-C-1-2. Rachidian is 3-cusped. All cusps are strong and pointed. The lateral tooth is massive and strong with a huge triangula cusp. Two marginal teethare slender, long and strong. 2. Cymatidae; Radula formula 2-1-c-1-2. Fachidian, 1-cusped. Cusp is strong and acute. The basal margin is toothed with a number of small denticles. The lateral tooth is beak-like and strong with groove inside. The marginal teeth are slender and pointed. 3. Tonnidae; Radula Formula 2-1-C-1-2. Rachidian, 3 cusped. Central cusp is huge, strong and abruptly pointed. Lateral cusp is blunt and relatively small. The lateral tooth and maginal teeth are identical to that of the preceding one. 4. Muricidae; Radula formula 1-C-1. Rachidian has 3 to 5 cusps. Central cusp, long, thick, strong and pointed. Lateral cusps are rather shorter than central, thick, strong and well cut with several minute denticles along outer margin. The lateral tooth is falciform. 5. Pyrenidae; Radula formula 1-c-1 Rachidian lacks of cusp. The base is thin, narrow, small and rectangular. Lateral tooth has 2 cusps with a crescent shaped base. 6. Buccinidae; Radula formula 1-C-1. Rachidian has 3 to 7 cusps. The base is massive and broadened laterally. The lateral tooth is large-and has 2 to 4 cusps. The central cusp is the shortest, and become longer towards the each side. 7. Busyconidae ; Radula formula 1-C-1. Rachidian, 3-cusped with a massive base. All cusps are pointed and strong. Centeral cusp is rather shorter than lateral one. Lateral tooth, 2-cusped. Inner cusp short about one half the length of outer one. 8. Fasciolariidae; Radula formula 1-C-1. Rachidian, 3 to 4-cusped. Very small in size. Lateral tooth broadened laterally with about 10 thin, long, sharp cusps. 9. Volutidae ; Only the rachidian exists. Rachidian, 3-cusped. All cusps are strong and sharply pointed. Central cusp is narrower than lateral ones. Anterior basal margin is concave.

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MEASUREMENT OF ADHESION OF ROOT CANAL SEALER TO DENTINE AND GUTTA-PERCHA (상아질과 Gutta-Percha에 대한 근관충전용 Sealer의 결합강도의 측정)

  • Her, Mi-Ja;Yu, Mi-Kyung;Lee, Se-Joon;Lee, Kwang-Won
    • Restorative Dentistry and Endodontics
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    • v.28 no.1
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    • pp.89-99
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    • 2003
  • The purpose of this study was to investigate the bonding of resin- based root canal sealer, AH26 when the sealer was applied as a thin layer between dentine and gutta-percha surface. In this study forty non-caries extracted human molars and resin-based root canal sealer(AH 26, DeTrey/Dentsply, Germany) were used. Disks of gutta-percha, 6mm in diameter.6mm thick (Diadent/Dentsply, Korea) for thermoplastic obturation were used and dentin surfaces were treated with 2% NaOCl(Group 1) or 2%NaOCl+17% EDTA(Group 3). Disks of gutta-Percha, 6mm in diameter.6mm thick (Diadent/Dentsply, Korea) for conventional obturation were used and dentin surface were treated with 2% NaOCl(Group 2) or 2%NaOCl+17% EDTA(Group 4). Enamel was removed by a horizontal section 1mm below the deepest portion of the central occlusal groove by using a watercooled low speed diamond saw. A second horizontal section was done around cementoenamel junction. Exposed dentin surface was cut to approximately $8{\times}8{\;}mm$ rectangular shape and was ground against 320, 400, 600 grade silicon carbide abrasive paper serially. After grinding, the dentine surface were soaked in a solution of 2% NaOCl for 30 minutes and twenty of specimens were treated with 17% EDTA solution for 1 minute. The treated specimens were washed and dried, Root canal sealer, AH26 was prepared according to the manufacture's instructions The Gutta-percha and dentin surface were coated with a thin layer of the freshly mixed seal or. The specimens were left overnight at room temperature. After their initial set, they were transferred to an incubator at $37$^{\circ}C$ for 72 h. After 72 hours, resin blocks were made. The resin block was serially sectioned vertically into stick of $1{\cdot}1mm$. Twenty sticks were prepared from each group. After that, tensile bond strength f3r each stick was measured with Microtensile Tester Failure patterns of the specimens at the interface between gutta-percha and dentin were observed under the SEM(x1000) and Stereomicroscope (LEICA M42O, Meyer Inst., TX U.S.A) at 1.25 x25 magnification. The results were statistically analysed by using a One-way ANOVA and Tukey's test. The results were as follows; 1. Tensile bond strengths($mean{\pm}SD$) were expressed with ascending order as follows: Group 1, $3.09{\pm}$ 1.05Mpa : Group 2, $6.23{\pm}1.16MPa$ : Group 3, $7.12{\pm}1.07MPa$ : Group 4, $10.32{\pm}2.06MPa$. 2. Tensile bond strengths of the group 2 and 4 used disks of gutta-percha for conventional obturation were significantly higher than that of the group 1 and 3 used fir thermoplastic obturation. (p < 0.05). 3. Tensile bond strengths of the group 3 and 4 treated with 2% NaOC1+17% EDTA were significantly higher than that of the group 1 and 2 treated with 2% NaOCl. (p < 0.05). 4. In analysis of failure patterns at the interface between sealer and gutta-percha, there were observed 49 (61%)cases of adhesive failure patterns and 31 (39%) cases of mixed failures patterns.

Kim Eung-hwan's Official Excursion for Drawing Scenic Spots in 1788 and his Album of Complete Views of Seas and Mountains (1788년 김응환의 봉명사경과 《해악전도첩(海嶽全圖帖)》)

  • Oh, Dayun
    • MISULJARYO - National Museum of Korea Art Journal
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    • v.96
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    • pp.54-88
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    • 2019
  • The Album of Complete Views of Seas and Mountains comprises sixty real scenery landscape paintings depicting Geumgangsan Mountain, the Haegeumgang River, and the eight scenic views of Gwandong regions, as well as fifty-one pieces of writing. It is a rare example in terms of its size and painting style. The paintings in this album, which are densely packed with natural features, follow the painting style of the Southern School yet employ crude and unconventional elements. In them, stones on the mountains are depicted both geometrically and three-dimensionally. Since 1973, parts of this album have been published in some exhibition catalogues. The entire album was opened to the public at the special exhibition "Through the Eyes of Joseon Painters: Real Scenery Landscapes of Korea" held at the National Museum of Korea in 2019. The Album of Complete Views of Seas and Mountains was attributed to Kim Eung-hwan (1742-1789) due to the signature on the final leaf of the album and the seal reading "Bokheon(painter's penname)" on the currently missing album leaf of Chilbodae Peaks. However, there is a strong possibility that this signature and seal may have been added later. This paper intends to reexamine the creator of this album based on a variety of related factors. In order to understand the production background of Album of Complete Views of Seas and Mountains, I investigated the eighteenth-century tradition of drawing scenic spots while travelling in which scenery of was depicted during private travels or official excursions. Jeong Seon(1676-1759), Sim Sa-jeong(1707-1769), Kim Yun-gyeom(1711-1775), Choe Buk(1712-after 1786), and Kang Se-hwang(1713-1791) all went on a journey to Geumgangsan Mountain, the most famous travel destination in the late Joseon period, and created paintings of the mountain, including Album of Pungak Mountain in the Sinmyo Year(1711) by Jeong Seon. These painters presented their versions of the traditional scenic spots of Inner Geumgangsan and newly depicted vistas they discovered for themselves. To commemorate their private visits, they produced paintings for their fellow travelers or sponsors in an album format that could include several scenes. While the production of paintings of private travels to Geumgangsan Mountain increased, King Jeongjo(r. 1776-1800) ordered Kim Eung-hwan and Kim Hong-do, court painters at the Dohwaseo(Royal Bureau of Painting), to paint scenic spots in the nine counties of the Yeongdong region and around Geumgangsan Mountain. King Jeongjo selected these two as the painters for the official excursion taking into account their relationship, their administrative experience as regional officials, and their distinct painting styles. Starting in the reign of King Yeongjo(r. 1724-1776), Kim Eung-hwan and Kim Hong-do served as court painters at the Dohwaseo, maintained a close relationship as a senior and a junior and as colleagues, and served as chalbang(chief in large of post stations) in the Yeongnam region. While Kim Hong-do was proficient at applying soft and delicate brushstrokes, Kim Eung-hwan was skilled at depicting the beauty of robust and luxuriant landscapes. Both painters produced about 100 scenes of original drawings over fifty days of the official excursion. Based on these original drawings, they created around seventy album leaves or handscrolls. Their paintings enriched the tradition of depicting scenic spots, particularly Outer Inner Geumgang and the eight scenic views of Gwandong around Geumgangsan Mountain during private journeys in the eighteenth century. Moreover, they newly discovered places of scenic beauty in the Outer Geungang and Yeongdong regions, establishing them as new painting themes. The Album of Complete Views of Seas and Mountains consists of four volumes. The volumes I, II include twenty-nine paintings of Inner Geumgangsan; the volume III, seventeen scenes of Outer Geumgangsan; and the volume IV, fourteen images of Maritime Geumgangsan and the eight scenic views of Gwandong. These paintings produced on silk show crowded compositions, geometrical depictions of the stones and the mountains, and distinct presentation of the rocky peaks of Geumgangsan Mountain using white and grayish-blue pigments. This album reflects the Joseon painting style of the mid- and late eighteenth century, integrating influences from Jeong Seon, Kang Se-hwang, Sim Sa-jeong, Jeong Chung-yeop(1725-after 1800), and Kim Hong-do. In particular, some paintings in the album show similarities to Kim Hong-do's Album of Famous Mountains in Korea in terms of its compositions and painterly motifs. However, "Yeongrangho Lake," "Haesanjeong Pavilion," and "Wolsongjeong Pavilion" in Kim Eung-hwan's album differ from in the version by Kim Hong-do. Thus, Kim Eung-hwan was influenced by Kim Hong-do, but produced his own distinctive album. The Album of Complete Views of Seas and Mountains includes scenery of "Jaundam Pool," "Baegundae Peak," "Viewing Birobong Peak at Anmunjeom groove," and "Baekjeongbong Peak," all of which are not depicted in other albums. In his version, Kim Eung-hwan portrayed the characteristics of the natural features in each scenic spot in a detailed and refreshing manner. Moreover, he illustrated stones on the mountains using geometric shapes and added a sense of three-dimensionality using lines and planes. Based on the painting traditions of the Southern School, he established his own characteristics. He also turned natural features into triangular or rectangular chunks. All sixty paintings in this album appear rough and unconventional, but maintain their internal consistency. Each of the fifty-one writings included in the Album of Complete Views of Seas and Mountains is followed by a painting of a scenic spot. It explains the depicted landscape, thus helping viewers to understand and appreciate the painting. Intimately linked to each painting, the related text notes information on traveling from one scenic spot to the next, the origins of the place names, geographic features, and other related information. Such encyclopedic documentation began in the early nineteenth century and was common in painting albums of Geumgangsan Mountain in the mid- nineteenth century. The text following the painting of Baekhwaam Hermitage in the Album of Complete Views of Seas and Mountains documents the reconstruction of the Baekhwaam Hermitage in 1845, which provides crucial evidence for dating the text. Therefore, the owner of the Album of Complete Views of Seas and Mountains might have written the texts or asked someone else to transcribe them in the mid- or late nineteenth century. In this paper, I have inferred the producer of the Album of Complete Views of Seas and Mountains to be Kim Eung-hwan based on the painting style and the tradition of drawing scenic spots during official trips. Moreover, its affinity with the Handscroll of Pungak Mountain created by Kim Ha-jong(1793-after 1878) after 1865 is another decisive factor in attributing the album to Kim Eung-hwan. In contrast to the Album of Famous Mountains in Korea by Kim Hong-do, the Album of Complete Views of Seas and Mountains exerted only a minor influence on other painters. The Handscroll of Pungak Mountain by Kim Ha-jong is the sole example that employs the subject matter from the Album of Complete Views of Seas and Mountains and follows its painting style. In the Handscroll of Pungak Mountain, Kim Ha-jong demonstrated a painting style completely different from that in the Album of Seas and Mountains that he produced fifty years prior in 1816 for Yi Gwang-mun, the magistrate of Chuncheon. He emphasized the idea of "scholar thoughts" by following the compositions, painterly elements, and depictions of figures in the painting manual style from Kim Eung-hwan's Album of Complete Views of Seas and Mountains. Kim Ha-jong, a member of the Gaeseong Kim clan and the eldest grandson of Kim Eung-hwan, is presumed to have appreciated the paintings depicted in the nature of Album of Complete Views of Seas and Mountains, which had been passed down within the family, and newly transformed them. Furthermore, the contents and narrative styles of Yi Yu-won's writings attached to the paintings in the Handscroll of Pungak Mountain are similar to those of the fifty-one writings in Kim Eunghwan's album. This suggests a possible influence of the inscriptions in Kim Eung-hwan's album or the original texts from which these inscriptions were quoted upon the writings in Kim Ha-jong's handscroll. However, a closer examination will be needed to determine the order of the transcription of the writings. The Album of Complete View of Seas and Mountains differs from Kim Hong-do's paintings of his official trips and other painting albums he influenced. This album is a siginificant artwork in that it broadens the understanding of the art world of Kim Eung-hwan and illustrates another layer of real scenery landscape paintings in the late eighteenth century.