• 제목/요약/키워드: Spirals

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A displacement solution for circular openings in an elastic-brittle-plastic rock

  • Huang, Houxu;Li, Jie;Rong, Xiaoli;Hao, Yiqing;Dong, Xin
    • Geomechanics and Engineering
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    • v.13 no.3
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    • pp.489-504
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    • 2017
  • The localized shear and the slip lines are easily observed in elastic-brittle-plastic rock. After yielding, the strength of the brittle rock suddenly drops from the peak value to the residual value, and there are slip lines which divide the macro rock into numbers of elements. There are slippages of elements along the slip lines and the displacement field in the plastic region is discontinuous. With some restraints, the discontinuities can be described by the combination of two smooth functions, one is for the meaning of averaging the original function, and the other is for characterizing the breaks of the original function. The slip lines around the circular opening in the plastic region of an isotropic H-B rock which subjected to a hydrostatic in situ stress can be described by the logarithmic spirals. After failure, the deformation mechanism of the plastic region is mainly attributed to the slippage, and a slippage parameter is introduced. A new analytical solution is presented for the plane strain analysis of displacements around circular openings. The displacements obtained by using the new solution are found to be well coincide with the exact solutions from the published sources.

Studying the Transmission of Epidemics via the Maritime Silk Road in the Novel Nights of Plague

  • Nan-A LEE
    • Acta Via Serica
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    • v.8 no.2
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    • pp.79-94
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    • 2023
  • The purpose of this study is to examine the descriptions of the transmission of plague along the Silk Road in Orhan Pamuk's 2022 novel Nights of Plague. Pamuk won the Nobel Prize in Literature in 2006, the first prize for Turkish literature. Pamuk's vast knowledge of epidemiological history, which has long fascinated him, comes to life in this novel as he describes the characters' battles against the plague in the East and West and how the plague was brought to the islands and spread along the Maritime Silk Road. One of the most important trade routes in human history, the Silk Road was not only a link between East and West trade and cultures but also a route for the transmission of bubonic plague during the medieval period onwards. It was this epidemic that contributed to the decline of the Silk Road. In the novel, a plague originating in China strikes the Ottoman coastal cities of Smyrna and Mingheria on its way to Europe via India. The epidemic is contained in Smyrna but the death toll spirals out of control when the plague reaches the island of Mingheria by sea. The spatial setting of the novel is an island, which means that it communicates with the outside world by sea. The only way the plague could have spread to an isolated island was by ship. Rats from different ports and ships would have traveled to other parts of the world or even countries to spread the plague. In Nights of Plague, the fact that the plague reached Mingheria via the maritime Silk Road is also proven by the route of the ships and various narratives. The novel confirms what many scholars have argued, that the Silk Road brought various goods from the East to the Roman Empire, along with deadly diseases, and that the sea routes were an important way for the plague to travel and spread.

A Study on the Traditional Costumes and Tattoo of the Maori (마오리族 傳統 服飾과 文身 考察)

  • 황춘섭;정현주
    • The Research Journal of the Costume Culture
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    • v.3 no.2
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    • pp.241-260
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    • 1995
  • The Maori's traditional clothing materials, basic forms of dress, and the pattern and technique of tatoo were examined in the present study in order to deepen the appreciation of the cultural heritage of the Maori. The research method employed was the analysis of written materials. And a fild-trip was also made for the study. The study was limitted to the traditional culture of body adornment of the Maori including the clothing which is preserved and practicing by them at the present day, and the origin and the process of the historical development of those are not included in the scope of the present study. Followings are the results of the study: (1) By far the most widely used fiber for Maori clothing is abtained from what is commonly called New Zealand Flax. The fiber of kiekie(Freycinetia baueriana) and cabbage trees(Cordyline spp.) may also be used. The strong, long-lasting fiber of toi(cordyline indivisa) is used for a prestige warrior's cloak. Flat strips of ti kauka(Cordyline australi) are also used as thatch on rain cloaks. (2) Regardless of technique used, Maori weaving is always worked horizontally from left to right. Traditionally the work was suspended between two upright turuturu or weaving sticks. As the work progressed a second pair of uprights was used to keep the work off the ground. These uprights were moved forward as required. Because the weaver sat on the ground, the working edge was kept at a height that was comfortable to reach. No weaving tools are used, the wefts(aho) being manipulated by the fingers. The two main Maori weaving techniques are whatu aho patahi(single-pair twining) and whatu aho rua(double-pair twining). (3) The Maori wore two basic garments - a waist met and a cloak. The cloth of commoners were of plain manufacture, while those of people of rank were superior, sometimes being decorated with feather or dyed tags and decorated borders. Children ran more-or-less naked until puberty, being dressed only for special events. Some working dress consisted of nothing more than belts with leaves thrust under them. Chiefs and commoners usually went barefoot, using rough sandals on journeys over rough country (4) The adornment of men and women of rank was an important matter of tribal concern as it was in chiefly persons that prestige of the group was centred, The durable items of Maori persons adornment were either worn or carried. Ornaments of various kinds were draped about the neck or suspended from pierced earlobes. Combs decorated the head. Personal decorations not only enhanced the appearance of men and women, but many had protective magical function. The most evident personal ornament was the hei-tiki made of jade or other material. Maori weapons were treasured by their owners. They served on bottle and were also personal regalia. A man of rank was not fully dressed without a weapon in hand. Also weapons were essential to effective oratory. (5) No man or woman of rank went without some tattoo adornment except in extremely rare instances when a person was too sacred to have any blood shed. The untattooed were marked as beeing commoners of no social standing. This indelible mark of rank was begun, with appropriate rite and ritual, at puberty. And tattoo marked the person as being of a marriageable age. Maori tattoo was unlike most traditional tattoo in that its main line were 'engraved' on the face with deep cuts made by miniature bone chisels. The fill-in areas were not tattooed with cuts but with the multiple pricks of small bone 'combs' that only lightly penetrated the skin surface. The instrument of tattoo consisted of small pots of pumice or wood into which was placed a wetted black pigment made from burnt kauri gum, burnt vegetable caterpillars or other sooty materials. A bird bone chisel or comb set at right angles on a short wooden handle was dipped into the gigment, that a rod or stick was used to tap head of this miniature adze, causing penetration of the skin surface. Black pigment lodged under the skin took on a bluish tinge. A full made facial tattoo consisted of major spirals with smaller spirals on each side of the nose and sweeping curved lines radiating out from between the brows over the forehead and from the nose to the chin. The major patterns were cut deep, while the secondary koru patterns were lightly pricked into the skin.

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Study on the pre-beneficiation of low grade scheelite ore using Knelson Concentrator (Knelson Concentrator를 이용한 저품위 회중석의 전처리 기술개발)

  • Jeon, Ho-Seok;Yang, Jeong-Il;Lee, Eun-Seon;Choi, Hee-Kyoung;Baek, Sang-Ho
    • Mineral and Industry
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    • v.26
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    • pp.13-21
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    • 2013
  • This study is carried out experiments on various factors for improving the grade of low grade scheelite by Knelson concentrator prior to the main beneficiation process. Even though there are several gravity separators such as Jig, Spirals and etc. for rougher concentrate, the KC3 Knelson Concentrator was adopted to get better separation efficiency and beneficiating effects for pre-concentration of the low grade scheelite ore. The feed samples was prepared to minus 1mm in size by crushing and grinding. The important factors in the KC3 Knelson Concentrator test were examined in terms of the variations such as number of treatment, feed rate, rotation speed of bowl(G force), water flow rate, pre-removal of magnetic minerals, feed size and feed grade. According to the result of experiment, it shows that the important technical variations are limited in terms of number of treatment, feed rate, feed size and feed grade. The final result shows that the KC3 Knelson Concentrator obtains the scheelite pre-concentrate of about $3%WO_3$ grade and 90% recovery, respectively, from the feed containing about $0.8-1.0%WO_3$ grade.

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Uplift Capacity of Spiral Bar through the Model Experiment (모형실험을 통한 스파이럴 기초의 인발저항력 검토)

  • Choi, Man Kwon;Yun, Sung Wook;Kim, Ha Neul;Lee, Si Young;Kang, Dong Hyeon;Yoon, Yong Cheol
    • Journal of Bio-Environment Control
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    • v.24 no.3
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    • pp.202-209
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    • 2015
  • This study compared and analyzed the measurements of pullout load according to the depth of reclamation in the foundation, compaction ratio of soil, spiral diameter, and soil textures in an experiment with a model and reached the following conclusions: The comparison results of extreme pullout load between farm and reclaimed soil show that farmland soil recorded a score that was 1.2~3 times higher than that of reclaimed soil. The investigator measured pullout load in farmland and reclaimed soil and observed a tendency of rising extreme pullout load according to the increasing depth of reclamation and compaction ratio with a similar load-displacement curve between the two types of soil. Extreme pullout load made a greater increase by the rising size of diameter than the increasing depth of reclamation, also making a considerably bigger increase according to the rising compaction ratio than the other conditions. Therefore, the spirals bar is expected to be available in soft soil foundation, as well as farmland as increasing buried deep of foundations, compaction rate, diameter of the spiral, ect.

Fine Structural Study on the Capture Thread-Producing Organs in Nephila clavata L.Kocn (Aranese: Araneidae) I. Aggregate Gladns (무당거미(Nephila clavata L.Koch) 포획사 생성기관의 미세구조에 관한 연구 I. 수상선)

  • 문명진;김우갑
    • The Korean Journal of Zoology
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    • v.32 no.3
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    • pp.211-220
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    • 1989
  • The fine structure of the aggregate glands-one of the capture thread producing organs-in the orb web spider, Nephila clavata L.Koch, is studied with light and electron microscopes. Gluey capture threads or sticky spirals of the orb web are originated from the silks of two flagelliform glands and four aggregate glands which are connected to the posterior spinnerets, and the arrangement fo their spigots(large spinning tubes) shows a charaterstic form called "triad". The aggregate galnd is composed of large and multilobed secretory portion and thick excretory duct surrounded by large irregular nodules. The excretory duct of the aggregate galnds basically consists of three superposed types of cells which are inner columnar epithelium, nodule-forming cells and outer connestives. The cuticles of the proximal duct near the secretory portion are composed of endocuticle and exocuticle, whereas ghe distal duct near the spinning tubes has a electron lucent subcuticle which had the functions of water removal and orientation of silk fibers. In the cytoplasmic process of the large and irregular nodule-forming cells surrounded by invaginations of the plasma membranes, numerous mitochondria and glycogen particles are contained. The maturational level of the nodule cells is perceived from the appearence of these cell inclusions. The secretory portion of the glands which porduce the secretory silk material shows two layers of the cells which are simple cuboidal epithelium and several connective layers. In the cytoplasm of the glandular epithelial cell, rough endoplasmic reticulums are well developed, and two types of secretory granules are observed. Between the adjacent epithelial cells, specialized septate junctions are formed along the plasma membranes.membranes.

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A Study of Metalworking Techniques Seen in the Gold Buckle from Seogam-ri Tomb No. 9 (석암리 9호분 출토 금제띠고리의 제작 방법 고찰)

  • Ro, Jihyun;Yu, Heisun
    • Conservation Science in Museum
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    • v.17
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    • pp.1-16
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    • 2016
  • The gold buckle excavated from Seogam-ri Tomb No. 9(National Treasure No. 189), one of the oldest gold artifacts discovered within the Korean Peninsula, was created using granulation techniques. The buckle is made with 22.8K gold sheets and features a decorative design with seven dragons in repousse metalwork. The outlines of the dragons and the edge of the buckle are finished with 23.8K gold wires and granules. Some curved sections of the buckle are also covered with an extra sheet of 23.8K gold, possibly added to repair defects discovered during production or thereafter. Gold wire used to render the dragon's nostrils is slightly lower in purity(23.3K) and was probably preferred in this case due to its increased hardness. As a result, the metal is better able to retain the complex shape of the dragons' nostrils, created by rolling gold wire into spirals. The buckle's gold granules are found in small, medium and large sizes and are presumed to have been bonded using copper. The foreheads and the bodies of the seven dragons are inset with turquoise and the eyes are decorated with red cinnabar/vermillion(HgS).

Ultrastructure of the Androgenic Gland of the Freshwater Prawn, Macrobrachium nipponense (징거미새우, Macrobrachium nipponense의 Androgenic Gland 미세구조)

  • 김대현;강정하;김대중;한창희
    • Development and Reproduction
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    • v.3 no.1
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    • pp.53-58
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    • 1999
  • The androgenic gland secretes a hormone, androgenic gland hormone, which is believed to act on the differentiation of the primary, secondary, and behavioral sex characteristics in most malacostracan crustaceans. This report presents the ultrastructural morphology of the androgenic gland in the freshwater prawn Macrobrachium nipponense. This gland, located in the coxopodite of the last pair of walking legs, was attached to the subterminal region of the sperm duct. The gland was composed of simple cellular strands, encased by a fibrous sheath. Microvilli were situated in the fibrous sheath, especially at the edge of each cellular strand. The androgenic gland cells had the large and round nucleus and rough endoplasmic reticulum arranged either in spirals or in concentric circles throughout the cytoplasm of the cell. They also had the well-developed Golgi complex and long mitochondria with flat and transverse cristae. The Golgi complex was similar to microvesicular cluster, but usually in the shape of typical dictyosomes, These features of androgenic gland cells coincides well with the protein/peptide secretion in their function. However, despite the apparent ultastructual equipment for protein/peptide secretion, no accumulation of materials secreted were noticed in the cytoplasm. Therefore it is strongly suggested that the transient transportation of the materials into the hemocoel has occurred just after synthesis.

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Seismic Performance and Flexural Over-strength of Hollow Circular RC Column with Longitudinal Steel Ratio 2.017% (축방향철근비 2.017%인 중공 원형 RC 기둥의 내진성능과 휨 초과강도)

  • Ko, Seong-Hyun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.21 no.1
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    • pp.1-8
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    • 2017
  • Three small scale hollow circular reinforced concrete columns with aspect ratio 4.5 were tested under cyclic lateral load with constant axial load. Diameter of section is 400 mm, hollow diameter is 200 mm. The selected test variable is transverse steel ratio. Volumetric ratios of spirals of all the columns are 0.302~0.604% in the plastic hinge region. It corresponds to 45.9~91.8% of the minimum requirement of confining steel by Korean Bridge Design Specifications, which represent existing columns not designed by the current seismic design specifications or designed by seismic concept. The longitudinal steel ratio is 2.017%. The axial load ratio is 7%. This paper describes mainly crack behavior, load-displacement hysteresis loop, seismic performance such as equivalent damping ratio, residual displacement and effective stiffness and flexural over-strength of circular reinforced concrete bridge columns with respect to test variable. The regulation of flexural over-strength is adopted by Korea Bridge Design Specifications (Limited state design, 2012). The test results are compared with nominal strength, result of nonlinear moment-curvature analysis and the design specifications such as AASHTO LRFD and Korea Bridge Design Specifications(Limited state design).

Web Structure of the Wasp Spider, Argiope bruennichi, Depending on Micro-Habitat Characteristics (미소서식지 특성에 따른 긴호랑거미 (Argiope bruennichi)의 웹 구조 분석)

  • Kim, Kil-Won;Kim, Duk-Rae;Jin, Woo-Young
    • Journal of Wetlands Research
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    • v.12 no.1
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    • pp.41-49
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    • 2010
  • Web building of the spider is an investment behavior for prey foraging with genetic constraint. Individual's decision-making on the web construction depends on diverse environmental variables. This study investigated web structure of the wasp spider, Argiope bruennichi, to compare individual's behaviors in dry field and in wet field. We measured 35 web structures in dry field (Chunma-San, Incheon) showing relatively low humidity (46.4%) and luxuriant herbage, and 13 web structures in the wet rice field (73.9%; Taean-Gun, Chungnam). Comparing to the wet field the individuals in the dry field invested significantly more silk: $32.5{\pm}12.8$ number of silk spirals used in the dry field vs. $16.9{\pm}5.4$ in the wet field. The web area of the dry field was greater than that of the wet field: $976{\pm}643cm^2$ vs. $532{\pm}254cm^2$. The web height, distance between the ground and the center of the web, appeared higher in the dry field than in the wet field: $71.4{\pm}39.6cm$ vs. $49.6{\pm}31.2cm$. Also the web constructed in the dry field showed longer stabilimentum than the web of the wet field: $18.8{\pm}3.4cm$ vs. $3.9{\pm}3.2cm$. The perpendicular inclination and the inclination to East-West of the web showed no difference between the two fields. This study suggests that adult females of A. bruennichi could modulate its construction behavior depending on the micro-habitat factors.