• Title/Summary/Keyword: Oval-tube

Search Result 32, Processing Time 0.02 seconds

Characteristics of Electrical Type Pressure Transducer Which uses Bourdon Tube (Bourdon관을 이용한 전기식 압력변환기의 특성)

  • 김기중;백재규;한응교
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.7 no.1
    • /
    • pp.14-22
    • /
    • 1983
  • The Bourdon tube pressure gauge is the most widely used primary detector for pressure in various kinds of fields recently. However in many cases lots of difficulties are encountered in telemetering, measuring the continuously changing pressure and recording as time goes by, etc. In this paper a Bourdon tube of flat-oval section is considered. On the basis of Wolf's theory, the very sensitive places are selected on the tube and full bridge arrangement is used. Then all of the characteristics are examined in order to use the pressure transducer practically into which the pressure gauge is converted. From the results, the error in meter reading is about $\pm$3% F.S., on the other hand, when measured with strain gauge, the error is within $\pm$1% F.S.. Also external acceleration on Bourdon tube hardly affect practical use.

  • PDF

Numerical Study for Air-Side Flow Characteristics of Fin-Tube Heat Exchangers with Oval-Tube (타원관형 핀-관 열교환기의 공기측 열유동특성에 대한 수치해석)

  • 김승택;최윤호;김형택
    • Journal of Energy Engineering
    • /
    • v.10 no.2
    • /
    • pp.166-175
    • /
    • 2001
  • 핀-관 열교환기의 효율을 증대시키기 위하여는 열저항을 결정하는데 있어서 중요한 역할을 하는 공기측 열전달 특성의 향상이 필요하다. 본 연구에서는 슬릿핀과 같은 핀 형상의 개선으로 인한 높은 압력손실을 감소시키기 위하여 타원관형 열교환기를 고려하였으며 이를 자체 개발한 3차원 비압축성 Navier-Stokes 코드를 이용하여 공기측 성능을 해석하였다. 이 코드는 시간항에 스칼라 내재적 근사분해법(scalar implicit approximate factorization)절차, 공간항에 유한체적법과 2차의 풍상차분법을 사용한다. 핀 형상이 평판핀인 타원관에 대하여 세장비가 0.3, 0.5, 0.75인 경우와 핀 형상이 슬릿핀이고 세장비가 0.5인 타원관에 대하여 공기측 유동을 해석하였으며 이를 원관의 성능과 비교하였다. 평판핀의 경우, 압력강하량은 원관과 비교하여 세장비가 작아질수록 감소하는 것을 볼 수 있었으며, 열전달 계수는 고려한 유입속도 범위에서 원관을 기준으로 약 5%이하의 변화로 거의 동일하게 유지되는 것을 볼 수 있었다. 슬릿핀의 경우 역시 문제되는 높은 압력강하량은 타원관을 도입함으로써 효과적으로 낮출 수 있음을 볼 수 있었다.

  • PDF

SMALL $H_3^+$ EMISSION PATCHES IN THE VICINITY OF JUPITER'S AURORAL REGIONS

  • KIM YONG-HA;KIM SANG JOON
    • Journal of The Korean Astronomical Society
    • /
    • v.28 no.1
    • /
    • pp.89-95
    • /
    • 1995
  • We examined a total of 166 images of $3.5{\mu}m\;H_3^+$ emission in the auroral regions of Jupiter observed with the Protocam on IRTF in 1991 and 1992, and found that 30 images contain a clearly isolated small emission patch in the vicinity of the northern auroral regions. Two different time sequences of the images show the small patches at the dusk limb in the range of System III longitudes from $270^{\circ}\;through\;0^{\circ}\;to\;90^{circ}$. The small patches in one sequence of the images, which were taken at 10 phase between $240^{\circ}\;and\;260^{\circ}$, may be related to the 10 flux tube, similarly suggested by Connerney et al. (1993). However, the small patches in the other sequence are separated from Io as much as $80^{\circ}$ in longitude. The positions of the small patches in both sequences are deviated equatorward from the 10 footprint oval by $5^{\circ}-8^{\circ}$ latitude in the longitudinal range of $270^{\circ}-360^{\circ}$. A significant modification is required in current Jovian magnetic field models near the Jupiter's surface if the small patches are produced at the foot of the 10 flux tube.

  • PDF

Novel Discovery of Two Heterotrichid Ciliates, Climacostomum virens and Fabrea salina (Ciliophora: Heterotrichea: Heterotrichida) in Korea

  • Kim, Ji Hye;Shin, Mann Kyoon
    • Animal Systematics, Evolution and Diversity
    • /
    • v.31 no.3
    • /
    • pp.182-190
    • /
    • 2015
  • Two heterotrichid ciliates, Climacostomum virens (Ehrenberg, 1838) Stein, 1859 from brackish water and freshwater, and Fabrea salina Henneguy, 1890 from a solar saltern, were collected in Korea. They are novelly investigated in Korea by means of live observation, protargol staining and nuclear small subunit (SSU) rRNA gene sequencing. Climacostomum virens is characterized by pouch-like body shape, body length of $200-370{\mu}m$ in vivo, conspicuous cytopharyngeal tube, macronuclei ribbon-like shape, and one to four in number, with or without symbiont algae in cytoplasm, 34-66 somatic kineties, 67-113 adoral zone of membranelles, 8-42 peristomial kineties, 24-37 apical membranelles. SSU rDNA sequence size is 1,591 bp and GC contents 48.52%. Fabrea salina is also characterized by scoop-like body shape with proboscis, body length of $190-240{\mu}m$ in vivo, one to two rod-shaped macronuclei, oval micronuclei, grayish green cortical granules, 104-186 somatic kineties, 4-8 preoral kineties, 7-19 peristomial kineties and fragmented paroral membrane. SSU rDNA sequence size is 1,598 bp and GC contents 47.50%.

Multicystic Pulmonary Parenchymal Lesions in a Young Adult with Hemoptysis (폐실질내 다발성 낭종으로 발현한 기관지기원낭)

  • Choi, Kyoung A;Koh, Won-Jung;Lee, Kyung Soo;Han, Joungho;Kim, Kwhanmien
    • Tuberculosis and Respiratory Diseases
    • /
    • v.62 no.1
    • /
    • pp.71-73
    • /
    • 2007
  • Bronchogenic cysts are commonly located in the mediastinum or lung parenchyma, and arise from the abnormal budding of the primitive tracheobronchial tube. Cough and pain are the most common symptoms. Bronchogenic cysts appear as spherical or oval masses with smooth outlines and are usually unilocular and noncalcified. We report a young adult with a bronchogenic cyst presenting as multicystic pulmonary parenchymal lesions. This case is very unusual because a multicystic intrapulmonary bronchogenic cyst is very rare in adults.

Geology of the Hawaii Island and Volcanic Activities of Mauna Loa and Kilauea (하와이 섬의 지질과 마우나로아 및 킬라우에아의 화산활동)

  • 황상구;이문원;원종관;우경식;이광춘
    • The Journal of the Petrological Society of Korea
    • /
    • v.12 no.4
    • /
    • pp.184-195
    • /
    • 2003
  • Hawaii Island makes up of five volcanos of Kohala, Mauna Kea, Hualalai, Mauna Loa, and Kilauea. They are big shield volcanoes rising above the Pacific ocean floor and final two volcanoes provide a natural laboratory for the study of active volcanoes. Mauna Loa is the largest single volcano on earth. At the submmit is an oval-shaped Mokuaweoweo caldera, from which two rift zones extend to the southwest and northeast, and in the medial part are the longest lava tube systems in the world. Kilauea has been formed largely by eruption along southwest and eastern rift zones extending from Kilauea caldera at the submmit. On the eastern rift zone, spectacularly, the 1989-1974 eruption of Kilauea at Mauna Ulu crater formed the Mauna Ulu lava flow field. The 1983-1986 eruption of aa flows at Puu Oo crater, and the activities of pahoehoe flows during 1986-1990 at Kupaianaha crater and during 1991-recent at the Puu Oo has produced the Puu Oo and Kupaianaha lava flow field.

Tuned mass dampers for human-induced vibration control of the Expo Culture Centre at the World Expo 2010 in Shanghai, China

  • Lu, Xilin;Ding, Kun;Shi, Weixing;Weng, Dagen
    • Structural Engineering and Mechanics
    • /
    • v.43 no.5
    • /
    • pp.607-621
    • /
    • 2012
  • The Expo Culture Centre is one of the permanent buildings at the World Expo 2010 in Shanghai, China. The main structure has an oval shape and consists of 36 radial cantilever steel trusses with different lengths and inner frames made of concrete-filled rectangular steel tube members. Tuned mass dampers are used to reduce the excessive vibrations of the sixth floor that are caused by human-induced resonance. A three-dimensional analytical model of the system is developed, and its main characteristics are established. A series of field tests are performed on the structure, and the test results show that the vertical vibration frequencies of most structural cantilevers are between 2.5 Hz and 3.5 Hz, which falls in the range of human-induced vibration. Twelve pairs of tuned mass dampers weighing 115 tons total were installed in the structure to suppress the vibration response of the system. These mass dampers were tuned to the vertical vibration frequency of the structure, which had the highest possibility of excitation. Test data obtained after the installation of the tuned mass dampers are used to evaluate their effectiveness for the reduction of the vibration acceleration. An analytical model of the structure is calibrated according to the measured dynamic characteristics. An analysis of the modified model is performed and the results show that when people walk normally, the structural vibration was low and the tuned mass dampers have no effect, but when people run at the structural vibration frequency, the tuned mass dampers can reduce the floor vibration acceleration by approximately 15%.

TEMPORAL VARIATIONS OF IO'S MAGNETIC FOOTPRINT BRIGHTNESS

  • WANNAWICHIAN, SUWICHA;PROMFU, TATPHICHA
    • Publications of The Korean Astronomical Society
    • /
    • v.30 no.2
    • /
    • pp.61-64
    • /
    • 2015
  • The brightness of Io's magnetic footprint, an indicator of electromagnetic interaction at the satellite, appears to be strongly connected to the satellite's distance from the plasma equator. As a result, the brightest footprints were detected when Io is near the interception location between the satellite's orbital plane and the plasma equator. However, volcanic activities on Io show strong correlation with the equatorward shift of Jupiter's main auroral oval, consequently causing the disappearance of Io's footprint. The same conclusion was suggested via the observation of Jupiter's hectometric radio emission, called HOM, which closely corresponds to Jupiter's auroral activity. The plasma environment near the Jovian satellites was found to vary significantly at different observational epochs. The electron density increased by approximately a factor of three from the Voyager epoch (1979) to the Galileo epoch (1995), while the electron density was found to be significantly higher (~ 5 times) in the Cassini epoch (2001). In this current study, the magnetic footprints were clearly brighter ten years ago (from peak brightness in 1998-2001) than the footprints detected in 2007. For volcanic activities on Io in 2007, there are two clear activities in February and late May. The magnetic footprint appeared to be dimmer in March 2007, expected to be the result of volcano activities in Feb 2007. However, the magnetic footprint brightness in June appeared to be slightly brighter than the footprints observed in May. The reason could be the time delay between the brightening of the sodium nebula on approximately May 31st and, a while later, the enhancement of flux tube content peaking on approximately June 5th. On the other hand, Io's magnetic footprints were observed during June 1st - 10th when they may not yet have been affected by the increase in mass outflow due to the increase of plasma density.

Identification and prevalence of trematode(Gen Azygia) and nematode(Gen Pingus) in Ophicephalus argus (가물치의 위장내 기생하는 흡충(Azygia속) 및 선충(Pingus속)의 동정과 감염상황)

  • Moon, Moo-hong;Lee, Eun-woo
    • Korean Journal of Veterinary Research
    • /
    • v.38 no.1
    • /
    • pp.147-159
    • /
    • 1998
  • A survey of the internal parasites in 115 fishes of Ophicephalus argus was carried out in Kyungpook province during the period from January 1995 to November 1997. A species of trematode from the stomach and a species of nematode from the caeca of the fishes was discovered respectively. The trematode was identified as Azygia hwangtsinyi (Tsin, 1993) and the nematode as Pingus sinensis ($Hs\ddot{u}$, 1993). The fluke was pressed at thick of 0.1mm~0.2mm between slide glasses and fixed in 70% ethyl alcohol solution. The fluke was washed with tap water after fixation and stained with hematoxylin-carmin and mounted in balsam through routine methods. The nematode was fixed in 5% formalin solution and mounted with lactophnol or glycerine jelly. Morphology : Arygia hwantsinyi ; The fluke is elongate body with approximately parallel margins and rounded extremities in pressed preparations(Fig 1). The cuticle is unarmed. The oral sucker is ventro-subterminal in position. The ventral sucker is slightly smaller than oral sucker and positioned at 14.2% of body length from the oral sucker. The cirrus sac and genital pore is in mid-ventral line, slightly anterior to the ventral sucker. The oral sucker is succeeded by a well developed muscular pharynx. It is succeeded by a short inverted Y-shaped oesophagus. The inner wall of oesophagus is consisted of many fine folded membrane. The fine tubes of esophagus pass into the intestinal heads which are distended and presented a marked borderline between the fine tube and intestinal heads. The Intestinal heads start at level of pharynx and pass caudad in a zigzag course to end quite near caudal margin. The uterine coils occupy the intercecal area between the level of the cephalic margin of the ovary and about the level of the ventral sucker. The uterus is filled with many eggs. The testes are round or oval and placed one behind the other generally a little diagonally. The posterior testis is placed at level of 75.1% of body length. The ovary is oval, placed ahead the anterior testis. The shell gland not discernible outline is contacted with ovary ahead it. The vitelline glands are consisted of small oval vesicles. The vesicles occupy extracecal regions and between a little posterior of the ventral sucker and near caudal margin. Pingus sinensis : Female ; The cuticle is smooth and the cervical alae are well developed. The mouth opening is small, triangular, and without lips. The anterior end bears four sub-medial papillae. The oesophagus is divided into a muscular and glandular portion. The nerve ring is situated just at the junction of the muscular and glandular portions of the oesophagus. The vulva which has a prominent flap, is placed behind the middle of the body about one-third of the length of the worm from the posterior extremity. The vagina is strongly muscularised and after running anteriorly about $68{\mu}$, divides itself into two broad uterine tubes with an anterior and a posterior one. There are a few eggs in the uterine tubes. The tail is slender, straight and pointed. The ovary extends almost to the posterior extremity. Male : Male is smaller than female. The tail is pointed, curved and carrying well-developed caudal alae. A prominent muscular precloacal sucker is characteristic. The spicules are equal and short. There are four pairs of pedunculated pre-anal papillae, of which the most anterior pair are situated just at the level anterior to the muscular sucker. Two pairs of pedunculated papillae are present before the anus. There are five pairs of post-anal papillae of which the most anterior pair and the second counted from the posterior end are ventral and more marked than the ones which are situated laterally.

  • PDF

Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013 (설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.26 no.12
    • /
    • pp.605-619
    • /
    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.