• Title/Summary/Keyword: Air-bleeding

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Properties of fresh concrete using lime stone powder (석회석미분말을 사용한 굳지않은 콘크리트의 특성)

  • Cho, Il-Ho;Sung, Chan-Yong
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2005.10a
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    • pp.108-112
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    • 2005
  • In this research, the physical properties of fresh concrete using lime stone powder as a part of cement were investigated. Fresh concrete using lime stone powder was prepared with various lime stone powder replacement($5{\sim}12$ volume %) for cement and the quantities of sand aggregate ratio in concrete were 47.3%, 48.5% and 49.4% of ratio of sand aggregate. The workability, flowing characteristics, air content and bleeding of concrete using lime stone powder were tested and the results were compared with those of ordinary portland cement concrete. In the experiment, we acquired satisfactory results at the point of fresh concrete characteristics using lime stone powder within the replacement ratio of $8{\sim}12%$ and the optimum quantity of sand aggregate ratio in concrete was found to be $48.5%{\sim}50%$ of ratio of sand aggregate.

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Properties of the Concrete using the Waste Foundry Sand Powder by Cement Replacement (폐주물사 미분말을 시멘트 대체재료로 사용한 콘크리트의 특성)

  • Woo Jong-Kwon;Ban Joo-Hwan;Ryu Hyun-Gi
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2006.05a
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    • pp.57-61
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    • 2006
  • Waste foundry sand of industrial waste which is happening by vast quantity according to fast development of industry has much the occurrence amount and processing method is depended on reclamation, and is using by fine aggregate for construction by recycling method among others. In this research Waste foundry sand powder into cement replace fare use possibility availability judge wish to Slump and air content decreased the replacement ratio increases by concrete special quality that do not harden according to experiment result, and unit capacity mass and bleeding increased the replacement ratio increases. Hardening concrete intensity special quality displayed strength improvement to replacement ratio 20%, and tendency that watertightness increases most in replacement ratio loft in watertight property appear. Considering the strength and watertight properties, the adequate usage of waste foundry sand powder is the 10% of replacement ratio.

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Properties of Polymer Modified Mortars Substitution Re-dispersible Polymer Powders (재유화형 폴리머를 첨가한 폴리머시멘트 모르타르의 특성)

  • Jang, Kun-Young;Ryu, Dong-Woo;Jeon, Chan-Soo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2018.05a
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    • pp.19-20
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    • 2018
  • For this study, a test was conducted on the basic polymer property depending on the replacement amount of polymer. The result showed that the flow of slump was increased with the increase of polymer replacement amount and an amount of air entraining. In addition, with a decrease of unit W/B, an amount of bleeding was reduced, and the first and final time for 6% replacement amount was found to be the fastest. This implies that replacement of more than 6% may affect the hydration of cement.

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Physical Properties of Concrete with the Contents of CSA Expansive Admixture (CSA계 혼화재 치환율 병화에 따른 콘크리트의 물리적 성질)

  • Pei Chang Chun;Park Young Shin;Lee Mun Hwan;Han Cheon Goo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.05b
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    • pp.369-372
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    • 2005
  • This study is about physical properties of concrete with changing displacement ratio of calcium sulfa aluminates(CSA) type admixture. Firstly, test shows that as displacement ratio of CSA increases and setting properties changes, fluidity and air contents decreases. In water to binder ratio 35$\%$ and 45$\%$, concrete using the cement replacing CSA 4$\%$ by volume shows that bleeding decreases 94.7$\%$ and 74.3$\%$ respectively, compared with plain concrete. In addition, setting time was promoted around 3 to 6 hour and 1 to 4 hour respectively. For harden concrete, increase of displacement ratio caused tendency of higher compressive strength as OPC has at early age. Replacing higher CSA admixture led to reduce of drying shrinkage.

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The relationship between dental hygiene problems and dental hygiene planning according to oral health status (구강건강상태에 따른 치위생문제와 치위생계획의 연관성)

  • Kang, Hyun-Kyung;Kim, Yu-Rin
    • Journal of Korean society of Dental Hygiene
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    • v.18 no.5
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    • pp.665-674
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    • 2018
  • Objective: The purpose of this study was to reduce the burden on dental hygienists in performing dental hygiene processes in the clinic. This study systematically analyzed dental hygiene problems and dental hygiene planning according to the oral condition of patients by applying an oral health care program based on the dental hygiene process. Methods: This study analyzed influential factors of 17 dental hygiene problems and 12 dental hygiene plans according to the oral health index and charts of 185 patients. This study was approved by the Institutional Review Board (IRB No. 1041449-201801-HR-003) of Silla University. The frequency of dental hygiene problems and dental hygiene planning was analyzed and correlations among the oral health index, dental hygiene problems, and dental hygiene planning were analyzed. Results: The higher the bleeding on probing score was, the more scaling was planned. The higher the calculus rate was, the more air-jet and jaw joint disorder prevention education was planned. The higher the O'Leary index was, the more dietary education and air-jet was planned. The higher the Simplified Oral Hygiene Index was, the more air-jet and jaw joint disorder prevention education was planned. The higher the Periodontal Screening and Recording index was, the more scaling and professional tooth cleaning was planned (p<0.05). Conclusions: The burden of oral preventive duties on dental hygienists will be minimized by systematically establishing problems and planning of dental hygiene according to patients' oral health index scores. Therefore, it is expected that dental hygienist can actively use the dental hygiene process in oral health care programs.

On/Off-Design/Transient Analysis of a 50KW Turbogenerator Gas Turbine Engine (50KW 터보제너레이터용 가스터빈 엔진의 설계점/ 탈설계/과도성능해석)

  • Kim, Su-Yong;Park, Mu-Ryong;Jo, Su-Yong
    • 연구논문집
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    • s.27
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    • pp.87-99
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    • 1997
  • Present paper describes on/off design performance of a 50KW turbogenerator gas turbine engine for hybrid vehicle application. For optimum design point selection, relevant parameter study is carried out. The turbogenerator gas turbine engine for a hybrid vehicle is expected to be designed for maximum fuel economy, ultra low emissions, and very low cost. Compressor, combustor, turbine, and permanent-magnet generator will be mounted on a single high speed (82,000 rpm) shaft that will be supported on air bearings. As the generator is built into the shaft, gearbox and other moving parts become unnecessary and thus will increase the system's reliability and reduce the manufacturing cost. The engine has a radial compressor and turbine with design point pressure ratio of 4.0. This pressure ratio was set based on calculation of specific fuel consumption and specific power variation with pressure ratio. For the given turbine inlet temperature, a rather conservative value of $1100^\circK$ was selected. Designed mass flow rate was 0.5 kg/sec. Parametric study of the cycle indicates that specific work and efficiency increase at a given pressure ratio and turbine inlet temperature. Off design analysis shows that the gas turbine system reaches self operating condition at N/$N_{DP}$ = 0.53. Bleeding air for turbine stator cooling is omitted considering low TIT and for a simple geometric structure. Various engine performance simulations including, ambient temperature influence, surging at part load condition. Transient analysis were performed to secure the optimum engine operating characteristics. Surge margin throughout the performance analysis were maintained to be over 80% approximately. Validation of present results are yet to be seen as the performance tests are scheduled by the end of 1998 for comparison.

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The Bibliogrphical Study on the Allergic Rhinitis (알레르기性 鼻炎에 對한 文獻的 考察)

  • Kim, Hyun-Ah;Jung, Ji-Chun
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.7 no.1
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    • pp.53-84
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    • 1994
  • The study has been carried out to investigate of the Allergic Rhinitis by referring to 87 literatures. The results were as follows; 1. In oriental medical science, Allergic Rhinitis is belong to the category of the 'BiGu'(鼻구) 'GuChe'(구체). The 'Gu'(구) of the BiGu means watery rhinorrhea, the 'Che'(체) of the GuChe means sneezing. 2. The cause of a disease summarize the weak of Lung, Spleen and Kidney, and invasion into the nasal cavity of PoongHan etc a wrong air. Sometimes the pathologial change appear PoongHan changeHwa(風寒化火), HwaYeol is hidden in the inside(火熱內伏). The contributing factors are found a season(spring, winter), an abnormal weather(運氣 : 少陰 少陽 陽明 司天, 歲金不及), an emotional stress, an external wound of the harmful air, a food allergens and fatigue, a contact of substances, a sunlight etc. 3. Predominant symptoms are watery rhinorrhea, sneezing and nasal obstruction. Sometimes accompanic symptoms are nasal bleeding, mucopurulent rhinorrhea, olfactory disturbance, nasal polyp, rhinolalia clausa, respiratory disfunction etc. 4. The treatment-methodes is as follows, OnBoPaeJang GeoPoongSanHan(溫補肺臟 祛風散寒), GeonBilkGi(健脾益氣), BoSinNabGi (補腎納氣). The treatmentherbs is as follows, OnBoJiLuDan GaGam(溫補止流丹 加減), OkByeongPoongSan plus ChangIJaSan GaGam(玉屛風散合 蒼耳子散 加減), BoJungIkGiTang GaGam plus SoCheongLyongTang(補中益氣湯加減 配合 小靑龍湯), SinGiHwan GaGam(腎氣丸加減), GaeJiTang(桂枝湯) etc. 5. The external treatment is as follows, JeokBi(滴鼻), ChuiBi(吹鼻), SaekBi(塞鼻), stick and herbs-injection on the acupuncture-point, pressure ear acupuncture-point, herbs-pillow etc. 6. The acupuncture-moxa treatment is as follows, the methodes of cure apply TongJoGyeongGi(通調經氣), SanTongBiGui(宣通鼻竅) etc. Predominent acupuncture-points are YoungHyang(迎香), InDang(印堂), BiTong(鼻通), SangSeong(上星), HabGok(合谷) and so on. As mentioned above, from now on, it's need to the oriental medical scientific study of the Immunity and Allergy and to the external treatment's application for the ascent of the treatment-effect of the allergic disease.

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Video Assisted Thoracoscopic Surgery(VATS) of Mediastinal Masses (비디오 흉강경을 이용한 종격동 종양 절제술)

  • Won, Tae-Hui;Seong, Suk-Hwan;Kim, Ju-Hyeon
    • Journal of Chest Surgery
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    • v.27 no.3
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    • pp.226-229
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    • 1994
  • VATS is now used by many thoracic surgeons and in various anatomic locations such as lung parenchyme, pleura and mediastinum, etc. VATS of mediastinal masses has special characteristics compared to that of other diseases. Those are no positional changes of the mass during collapse of the lung and close proximity of the mass to major vascular structures, nerves and other vital organs. From 1992. July to 1993. August, 10 mediastinal masses were treated with video assisted thoracoscopy. There were five males and five females, ages ranged from 11 years to 65 years with average 37.7 17.7 years old. Of the 10 patients, 4 were bronchogenic cysts, 2 were teratoma, and the others were thymoma, neurilemmoma, pericardial cyst, and thymic cyst. Needle aspiration was done in large cysts and the working thoracotomy[or utility thoracotomy] was done in large solid masses for the purpose of easy dissection, easy handling and easy delivery of the mass. The average operation time were 155.6 6.8 minutes and the duration of air leakage were 1 2.2 days. The duration of the chest tube drainage were 3.3 2.6 days. The lengths of the postoperative hospitalization were 5.1 2.7 days which were shorter than those of 12 mediastinal masses treated with conventional thoracotomy during the same periods [p<0.05]. There was 1 patient converted to thoracotomy because of a bleeding at innominate vein. 3 postoperative complications were occured. Those were persistent air leakage for 7 days, diaphragmatic palsy and hoarseness which were recovered within 1 month. We conclude that mediastinal mass can be excised with video assisted thoracoscopy and the posthospitalization is reduced. But careful attention is required for avoiding injury to major vascular structures, nerves, and other vital organs.

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Change of Heat Transfer Characteristics in a Rotating Channel of Square Duct at Wall with Bleed Holes ( I ) - Effects of Rotation Speed - (회전하는 사각덕트 유로에서 벽면 유출홀에 따른 열전달 특성 변화( I ) -회전수 변화에 따른 영향 -)

  • Kim Sang In;Kim Kyung Min;Lee Dong-Hyun;Jeon Yun Heung;Cho Hyung Hee
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.17 no.10
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    • pp.898-906
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    • 2005
  • The present study has been conducted to investigate convective heat/mass transfer in the cooling passage with bleed holes. The rotating square channel has 40.0 mm hydraulic diameter and the bleed holes on the leading surface of the channel. The hole diameter of bleed hole is 4.5mm and its spacing is ( p/d:4.9) about five times of hole diameter. Exit mass flow rate through bleed holes is $10\%$ of the main mass flow rate and relation number is changed form 0.0 to 0.4. A naphthalene sublimation technique is employed to determine the detailed local heat transfer coefficients using the heat and mass transfer analogy The cooling performance is influenced by exit mass flow rate through bleed holes and Coriolis force of rotating channel for fixed Reynolds number. The heat transfer on the leading surface is decreased due to Coriolis force. However the total heat transfer is enhanced around holes on the leading surface because of trapping flow by bleeding.

Change of Heat Transfer Characteristics in a Rotating Channel of . Square Duct at Wall with Bleed Holes ( II ) - Effects of Exit Mass Flow Rate - (회전하는 사각덕트 유로에서 벽면 유출홀에 따른 열전달 특성 변화( ll ) -유출유량 변화에 따른 영향 -)

  • Kim Sang In;Kim Kyung Min;Lee Dong-Hyun;Jeon Yun Heung;Cho Hyung Hee
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.17 no.10
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    • pp.907-913
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    • 2005
  • The present study has been conducted to investigate convective heat/mass transfer in the cooling passage with bleed holes. The rotating square channel has 40.0 mm hydraulic diameter and the bleed holes on the leading surface of the channel. The hole diameter of bleed hole is 4.5mm and its spacing is ( p/d:4.9) about five times of hole diameter. Exit mass flow rate through bleed holes is $0\%,\;10\%\;and\;20\%$ of the main mass flow rate respectively. rotation number is fixed 0.2. A naphthalene sublimation technique is employed to determine the detailed local heat transfer coefficients using the heat and mass transfer analogy. The cooling performance is influenced by exit mass flow rate through bleed holes and Coriolis force of rotating channel for fixed Reynolds number. The heat transfer on the leading surface is decreased due to Coriolis force. However the total heat transfer is enhanced around holes on the leading surface because of trapping flow by bleeding.