• Title/Summary/Keyword: Appendages

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Numerical Analysis of the Wake of a Surface Ship Model Mounted in KRISO Large Cavitation Tunnel (KRISO 대형 캐비테이션터널 시험조건의 함정 모형선 반류에 대한 수치해석적 연구)

  • Park, Il-Ryong;Kim, Je-In;Kim, Ki-Sup;Ahn, Jong-Woo;Park, Young-Ha;Kim, Myoung-Soo
    • Journal of the Society of Naval Architects of Korea
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    • v.53 no.6
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    • pp.494-502
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    • 2016
  • The accurate assessment of hull-appendage interaction in the early design stage is important to control the inflow to the propeller plane, which can cause undesirable hydrodynamic effects in terms of cavitation phenomenon. This paper describes a numerical analysis for the flow around a fully appended surface ship model for which KRISO has carried out a model test in the Large Cavitation Tunnel(LCT). This numerical study was performed with the LCT model test in a complementary manner for a good reproduction of the wake distribution of surface ships. A second order accurate finite volume method provided by a commercial computational fluid dynamics(CFD) program was used to solve the governing Reynolds Averaged Navier-Stokes(RANS) equations, where the SST $k-{\omega}$ model was used for turbulence closure. The numerical results were compared to available LCT experimental data for validation. The calculations gave good predictions for the boundary layer profiles on the walls of the empty cavitation tunnel and the wake at the propeller plane of the fully appended hull model in the LCT.

Experimental Study on Estimation of Roll Damping for Various Midship Sections (중앙 단면 형상에 따른 횡동요 감쇠 추정 실험 연구)

  • Park, Byeongwon;Jung, Dong Woo;Jung, Jaesag;Park, Inbo;Cho, Seok-Kyu;Sung, Hong Gun
    • Journal of Ocean Engineering and Technology
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    • v.33 no.4
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    • pp.322-329
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    • 2019
  • The magnitude of the roll motion of a floating structure depends on the roll damping acting on the body. In other words, the roll damping of a floating structure must be accurately obtained in order to precisely evaluate the roll motion. Various methods are used to evaluate the roll damping of a floating structure, such as the linear potential theory, computational fluid dynamics (CFD), and model tests. However, it is difficult to evaluate the roll motion of a floating structure with appendages such as a bilge keel and riser slot due to the limitation of ignoring the viscous effects in the linear potential theory. Among these methods, a model test based on a free decay test and harmonic excited roll motion (HERM) is known to be the most reliable method to estimate the roll damping of the floating structures. In this study, model tests using free decay and HERM techniques were performed in the Ocean Engineering Basin (OEB) of KRISO with various types of midship sections. The roll damping results were estimated based on post-processing methods using both techniques, and the roll damping results were compared.

Taxonomic entity of Saussurea taquetii (Asteraceae) compared with S. japonica and S. pulchella (해변취의 실체: 큰각시취/각시취와의 관계)

  • SUN, Eun-Mi;YUN, Seon A;KIM, Seung-Chul;IM, Hyoung-Tak
    • Korean Journal of Plant Taxonomy
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    • v.51 no.4
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    • pp.378-385
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    • 2021
  • Saussurea taquetii reported from Jejudo Island is either treated as a synonym of S. japonica or is recognized as a distinct taxon. Saussurea japonica and S. pulchella belong to the sect. Theodorea by having peculiar outer phyllaries with pale purplish scarious apical appendages; they are closely related to each other morphologically and are known to occur widely throughout the Korean Peninsula. To assess the taxonomic status of S. taquetii, we investigated representative populations of S. taquetii from jejudo Island, Korea, and S. japonica from Kyushu in Japan. We conducted a comparative study morphologically using specimens of three species from KH, CNU, and TI. Saussurea taquetii is very similar morphologically and ecologically to S. japonica in Kyushu. Unlike previous floristic treatments, we concluded that the two taxa, S. pulchella and S. taquetii, occur on the Korean Peninsula and on jejudo Island, respectively.

Experimental Study of the Flat & Twisted Rudder Characteristics Using Rudder Dynamometer in LCT (LCT에서 방향타 동력계를 이용한 평판 및 비틀림 방향타 특성의 실험적 연구)

  • Ahn, Jong-Woo;Paik, Bu-Geun;Park, Young-Ha;Seol, Han-Shin
    • Journal of the Society of Naval Architects of Korea
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    • v.58 no.6
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    • pp.391-399
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    • 2021
  • In order to investigate force and cavitation characteristics for the flat & twisted rudders in the Large Cavitation Tunnel (LCT), the rudder dynamometer was designed and manufactured. The measuring capacities of lift, drag and moment are ±1000 N, ±2000 N, and ±150 N-m, respectively. The present dynamometer uses the actuator with a harmonic drive to control the rudder angle without backlash. As the target ship is a military ship with twin shaft, each dynamometer was installed above the port & starboard rudders. After the installation of the model ship with all appendages, the model test composed of rudder force measurement and cavitation observation was conducted for the existing flat rudder & the designed twisted rudder. While the flat rudder showed the big difference of lift & moment between port & starboard, the twisted rudder presented a similar trend. The cavitation of the twisted rudder showed better characteristics than that of the flat rudder. Another set of model tests were conducted to investigate rudder performance by the change of the design propeller. There was little difference in rudder performance for the design propellers with slight geometric change. Through the model test, the characteristics of the flat & twisted rudders were grasped. On the basis of the present study, it is thought that the rudder with better performance would be developed.

A Study of Korean Medicine Hospital Inpatient Consulted by Korean Medicine Ophthalmology, Otolaryngology & Dermatology Department for Dermatology and Surgical Disease (피부과 및 외과 질환으로 한방안이비인후피부과에 의뢰된 한방병원 입원환자에 대한 고찰)

  • Heo, Eun-na;Jeong, Mi-rae;Kwon, Kang;Seo, Hyung-sik
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.35 no.4
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    • pp.95-105
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    • 2022
  • Objectives : The purpose of this study is to retrospectively analyze 3 years of inpatient dermatologic and surgical consultation to Korean medicine ophthalmology, otolaryngology & dermatology department in Korean medicine hospital. Methods : We classified dermatological and surgical inpatient consultations between September 1st, 2019 and August 31st, 2022, based on electronic medical record by gender, age, hospitalized department, categories of diseases. Results : Total number of consultations were 336. The proportion of female and male were 2.5:1, and the average of age was 65.6 and 60, respectively. The most frequently referred skin disease category was infectious skin disease(39.9%), followed by eczema(20.2%), dermatoses due to physical forces(10.1%), pigment anomalies(7.1%), nevi and tumors(4.8%), diseases of the skin appendages(4.2%), urticaria(3.9%), and others(4.9%). Consultations from department of Korean rehabilitation medicine, and Korean internal medicine were most common, because they have a comparatively large number of inpatients and long hospitalization period. In case of infectious disease and skin ulcer, patients from Korean internal medicine were frequently consulted due to characteristics of stroke and internal diseases. Conclusions : This study identified the frequency of consultation and the disease group with many requests for each department. Identifying the characteristics of diseases with a high frequency of consultation will prevent various dermatological problems that may occur by department. In addition, it was found that a prompt consultation was needed for accurate diagnosis and treatment in dermatological problem.

Morphological and Phylogenetic Analyses Reveal a New Species of Genus Monochaetia Belonging to the Family Sporocadaceae in Korea

  • Seong-Keun Lim;Kallol Das;Soo-Min Hong;Sang Jae Suh;Seung-Yeol Lee;Hee-Young Jung
    • Mycobiology
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    • v.51 no.2
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    • pp.87-93
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    • 2023
  • The fungal strain belonging to the genus Monochaetia of the family Sporocadaceae was isolated from hairy long-horned toad beetle (Moechotypa diphysis) during the screening of microfungi associated with insects from Gangwon Province, Korea. The strain KNUF-6L2F produced white, light brown to dirty black surface, and olivaceous green colonies with the higher growth, while the closest strain M. ilicis KUMCC 15-0520T were light brown to brown, and M. schimae SAUCC 212201T light brown to brown toward center. The strain KNUF-6L2F produced shorter (5.7-14.0 ㎛) apical appendages than M. ilicis (6.0-24.0 ㎛), but similar to M. schimae (7.0-12.5 ㎛). Three median cells of KNUF-6L2F were light brown to olivaceous green, whereas brown and olivaceous cells were observed from M. ilicis and M. schimae, respectively. And the strain KNUF-6L2F produced larger conidiogenous cells than M. ilicis and M. schimae. Additionally, phylogenetic analyses based on molecular datasets of internal transcribed spacer (ITS) regions, translation elongation factor 1-alpha (TEF1α), and β-tubulin (TUB2) genes corroborated the strain's originality. Thus, the strain is different from other known Monochaetia species, according to molecular phylogeny and morophology, hence we suggested the new species Monochaetia mediana sp. nov. and provided a descriptive illustration.

Aerodynamic Retrofit of Bridge and Energy Harvesting by Small Wind Turbines (소형 풍력발전기를 이용한 교량의 공력성능 개선 및 에너지 생산)

  • Kwon, Soon-Duck;Lee, Seongho;Lee, Hankyu
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.1A
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    • pp.27-33
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    • 2010
  • This study addresses a methodology to use small wind turbines for dual purposes, improving aerodynamic performance of flexible bridges and wind energy harvesting. A way to proper placement of small wind turbines on flexible bridges were proposed according on the analogy of conventional aerodynamic appendages. From the wind tunnel tests, it was found that the wind turbine attached like fairing was effective to reduce the vortex-induced vibration of bridge and the optimal spanwise interval of the wind turbine was 3-4.5 time of turbine diameter. Moreover the aerodynamic coefficients of the bridge were improved after installation of the wind turbines. Present results showed the general availability of wind turbine for improvement of aerodynamic performance and energy supply of flexible bridges although the capacity of wind power generation was strongly dependent on wind characteristics of the bridge site.

Signal Detection of DPP-IV Inhibitors using Spontaneous Adverse Event Reporting System in Korea (자발적 부작용 보고 데이터베이스를 이용한 DPP- IV inhibitor의 약물이상사례 분석)

  • Hyejung Pyo;Tae Young Kim;Su Been Choi;Hyeong Jun Jo;Hae Lee Kang;Jung Sun Kim;Hye Sun Gwak;Ji Min Han
    • Korean Journal of Clinical Pharmacy
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    • v.34 no.2
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    • pp.100-107
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    • 2024
  • Background: The purpose of this study was to detect signals of adverse events (AEs) of DPP-IV inhibitors using the KIDs-Korea Adverse Event Reporting System (KAERS) database. Methods: This study was conducted using AEs reported from January 2009 to December 2018 in the KIDs-KAERS database. For signal detection, disproportionality analysis was performed. Signals of DPP-IV inhibitor that satisfied the data-mining indices of reporting odds ratio (ROR) were detected. Results: Among the total number of 10,364 AEs to all oral hypoglycemic agents, the number of reported AEs related to DPP-IV inhibitors was 1,674. Analysis of reported AEs of DPP-IV inhibitors at the SOC levels showed that Respiratory system disorders were the highest at 4.31 (95% CI 3.01-6.17), followed by Skin and appendages disorders at 2.04 (95% CI 1.74-2.38). When analyzing AEs reported at the PT level, pharyngitis was the highest at 73.90 (95% CI 17.59-310.49), followed by arthralgia at 6.08 (95% CI 2.04-18.11), and coughing at 5.21 (95% CI 2.07-13.15). Conclusions: Based on the result of the study, deeper consideration is required according to the characteristics of the patients in prescribing DPP-IV inhibitors among oral hypoglycemic agents, and continuous monitoring of the occurrence of related Adverse Drug Reactions during administration is also required.

Occurrence of Powdery Mildew on Mung bean(Vigna radiatus L.) Caused by Sphaerotheca phaseoli (Sphaerotheca phaseoli에 의한 녹두 흰가루병 발생)

  • Lee, Sang-Yeob;Hwang, Soon-Jin;Lee, Snag-Bum
    • Research in Plant Disease
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    • v.8 no.3
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    • pp.166-170
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    • 2002
  • Powdery mildew of mug bean was found in Suwon on September 2000. Many white and powdery mycelial colonies appeared on leaves of the plants. Conidia with fibrosin bodies were ellipsoid to elongate-ellipsoid, 25~38$\times$16~22 ${\mu}{\textrm}{m}$ in size and farmed in chains. Conidiophores were erect on superfical mycelium, 67~100 ${\mu}{\textrm}{m}$ in length. Foot cells were cylindric with 37~65$\times$10~11 ${\mu}{\textrm}{m}$ in size. Appressoria were indisdinct. Germ tubes from conidia were simple, not branched. Dark brown cleistothecia were observed on the leaves of mung bean. Cleisto-thecia were globose or subglobose, 85~1130 ${\mu}{\textrm}{m}$ in size. Wall cells were irregularly polygonal with 15~45$\times$7~26 ${\mu}{\textrm}{m}$. Appendages were mycelioid, 6-11 per ascocarp, coloured, throught when mature or paler upwards, 1~7 septa, 192~223$\times$5~7 ${\mu}{\textrm}{m}$ in size. A single sun had in a cleistothecium and was ovoid or subglobose with 62~95$\times$50~67 ${\mu}{\textrm}{m}$ in size. Ascusspore had 8 spores in an ascus and rarely developed, mostly imatuna ellipsoid-ovoid with 16~24$\times$12~16 ${\mu}{\textrm}{m}$. On the basis of morphological characters of the conidial stage and teleo-morph, the fungus was identified as Sphaerotheca phaseoli.

Fine Structural Analysis of the Attachment Devices in the Jumping Spider Plexippus setipes (깡충거미 표면 접착장치의 미세구조 분석)

  • Moon, Myung-Jin;Park, Jong-Gu
    • Applied Microscopy
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    • v.39 no.2
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    • pp.149-156
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    • 2009
  • Fine structure of the dry adhesion system in the tarsal appendages of the jumping spider Plexippus setipes (Araneae: Salticidae) with examined using field emission scanning electron microscope (FESEM). The jumping spiders have the distinctive attachment apparatus for adhesion on smooth dry surface without sticky fluids. They attach to rough substrates using tarsal claws, however attachment on smooth surfaces is achieved by means of a tuft-like hair called a scopula. All eight legs have the scopulae with a pair of claws on the tip of feet, and each scopula is composed of two groups of setae that are capable of dry adhesion on smooth surface. The apex of each seta is flattened pad bearing many specialized adhesive setules on one side. The cuticular sensillae are interspersed at the dorsal surface of the seta. It has been revealed by this research that the contact area of the setule is always a triangular shape, and these cuticular surfaces are connected by the elongated stalks from the underlying setae. Moreover, adhesion between the numerous setules and the setae was prevented by the microscopic hairs, since these were interspersed on the upper side of the setae.