• Title/Summary/Keyword: Cold test

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Design and Implementation of Cold-Flow and Hot-Fire Test Stand of a Cryogenic Propellant Injector Used in LRE (초저온 추진제를 사용하는 액체로켓용 인젝터의 수류/연소시험장치 설계 및 제작)

  • Kim, Do-Hun;Park, Young-Il;Koo, Ja-Ye
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.05a
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    • pp.61-65
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    • 2010
  • To research and develop a liquid rocket engine injector, it needs empirical studies about the hydrodynamic and spray characteristics such as pressure drop, mixing and atomization. In this study, the design and implementation of lab-scale cold-flow/hot fire test stand which can supply cryogenic propellant and be controlled by time-critical LabVIEW cyclogram logic has been done. In order to visualize the spray of a liquid-centered swirl coaxial injector in cryogenic condition, LN2-GN2 cold-flow test has been done, and combustor assembly and thrust bed for LOX-$GCH_4$ hot-fire test have been fabricated.

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Use of ultrasound Doppler to determine tooth vitality in a discolored tooth after traumatic injury: its prospects and limitations

  • Cho, Yong-Wook;Park, Sung-Ho
    • Restorative Dentistry and Endodontics
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    • v.39 no.1
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    • pp.68-73
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    • 2014
  • When a tooth shows discoloration and does not respond to the cold test or electric pulp test (EPT) after a traumatic injury, its diagnosis can be even more difficult due to the lack of proper diagnostic methods to evaluate its vitality. In these case reports, we hope to demonstrate that ultrasound Doppler might be successfully used to evaluate the vitality of the tooth after trauma, and help reduce unnecessary endodontic treatments. In all three of the present cases, the teeth were discolored after traumatic injuries and showed negative responses to the cold test and EPT. However, they showed distinctive vital reactions in the ultrasound Doppler test during the whole observation period. In the first case, the tooth color returned to normal, and the tooth showed a positive response to the cold test and EPT at 10 wk after the injury. In the second case, the tooth color had returned to its normal shade at 10 wk after the traumatic injury but remained insensitive to the cold test and EPT. In the third case, the discoloration was successfully treated with vital tooth bleaching.

Standardization of Ice Mechanics Experimental Procedures in a Cold Room (Cold Room을 이용한 얼음 및 동토의 재료특성 계측 실험기법의 표준화)

  • Kim, Jung-Hyun;Choi, Kyung-Sik;Seo, Young-Kyo
    • Journal of Ocean Engineering and Technology
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    • v.21 no.2 s.75
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    • pp.60-66
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    • 2007
  • The first Korean cold room facility for ice mechanics experiments was assembled in 2004. Since then, the $4m{\times}6m$ cold room facility has been used, extensively under various environmental and loading conditions. After reviewing published references on cold room testing methods and also by trial and error, the standard procedures for testing and preparing laboratory ice material were established for the measurement of basic ice properties. In this paper, laboratory experimental techniques with the cold room facility and standard procedures established for ice material properties are introduced. Test specimens include laboratory-grown fresh water ice and frozen soils. Tests are carried out for unconfined compressive strength. Preparation and dimension of the specimen are the most important issues arising in cold room tests. The details of specimen preparation, testing procedure and strength test results are also discussed.

A study on the characteristic of electrogastrography according to the heat-cold patternization (한열성향에 따른 위전도 특성 연구)

  • Haa, Song-Yong;Kim, Min-Yong;Park, Young-Jae;Park, Young-Bae
    • The Journal of the Society of Korean Medicine Diagnostics
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    • v.12 no.1
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    • pp.131-141
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    • 2008
  • Background: In relation to a diagnosis of Korean Medicine, heat-cold is one of the most important indicators for evaluation. In spite of this importance, there has not been the study that tries to examine the change of indicators in an electrogastrography (EGG) according to the heat-cold patternization. Objective: The objective of this study is to establish the correlation between the heat-cold patternization and indicators of EGG by means of Standardized Questionnaire for Heat-Cold Patternization. Method: To conduct this study, we used the method as follows: Before conducting EGG, subjects were requested to give answers to the questionnaire which was developed by Kim. Before EGG, subjects were demanded to fast for more than 8 hours and then eat the test meal. Before eating the test meal(test meal: two slices of bread, 4oz of apple juice), EGG signals were detected for 30 minutes, and then subjects could eat the test meal for 10 minutes. After eating the test meal, EGG signals were detected for 30 minutes. Results: 1. There was a negative correlation between heat score and the power ratio of channel 1 and channel 2 of EGG. There was a positive correlation between cold score and the power ratio of channel 1 of EGG. 2. There was a positive correlation between heat score and pre-prandial gastric arrhythmia in the channel 1, 2 and 4 of EGG. There was a negative correlation between cold score and post-prandial gastric arrhythmia in the channel 1, 2 and 3 of EGG. 3. There was a negative correlation between heat score and normal pre-prandial gastric slow wave in the channel 1, 2 and 4 of EGG. There was a positive correlation between cold score and normal post-prandial gastric slow wave in the channel 3 of EGG. Conclusions: From the results above, we could conclude as follows: Indicators of EGG and cold score presented a positive correlation, and heat score displayed a negative correlation. As a result, to apply EGG to a diagnosis of functional indigestion, the application of EGG to subjects who have heat patternization would increase the reliability of a diagnosis.

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The Use of Multiple Seed Vigor Indices to Predict Field Emergence and Grain Yield of Naked and Malting Barley (복합종자세지수를 이용한 보리 포장출아률과 수량예측)

  • Kim, Seok-Hyeon;Bin, Yeong-Ho;Choe, Zhin-Ryong
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.34 no.2
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    • pp.134-141
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    • 1989
  • In order to estimate field seedling emergence and grain yield by the information collected from various laboratory seed vigor tests, each two malting and naked barley cultivar seeds were artificially aged according to the standard aging treatment suggested by the Association of Official Seed Analysts. The seed vigor tests adopted were warm- and cold-germination test, tetrazolium vigor test and electrocon. ductivity test. Field emergence of malting barley (Y) was estimated by Y=-2.962+0.229X$_1$ (% warm germination) -0.001X$_2$ (vigor of warm germination test: WGT) +0.354X$_3$ (vigor of cold germination test: CT) -0.558X$_4$ (% cold germination). The multiple correlation coefficient indicated that % warm germination. was contributed 64 % of the variation in seedling emergence rate of malting barley. The vigor of warm and cold germination tests, and % cold germination contributed additional 4, 7, and 9%, respectively, upon addition of the variables into regression. For naked barley, the regression equation of emergence rate was less efficient(R$^2$=54%) than that of malting barley(R$^2$=84%). A model to predict grain yield by the results of various seed vigor tests was not evaluated for both malting and naked barlev.

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Structural performance of cold-formed steel composite beams

  • Dar, M. Adil;Subramanian, N.;Anbarasu, M.;Dar, A.R.;Lim, James B.P.
    • Steel and Composite Structures
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    • v.27 no.5
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    • pp.545-554
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    • 2018
  • This study presents a novel method of improving the strength and stiffness of cold-formed steel (CFS) beams. Flexural members are primary members in most of the structures. Hence, there is an urgent need in the CFS industry to look beyond the conventional CFS beam sections and develop novel techniques to address the severe local buckling problems that exist in CFS flexural members. The primary objective of this study was to develop new CFS composite beam sections with improved structural performance and economy. This paper presents an experimental study conducted on different CFS composite beams with simply supported end conditions under four point loading. Material properties and geometric imperfections of the models were measured. The test strengths of the models are compared with the design strengths predicted by using Australian/New Zealand Standard for cold-formed steel structures. Furthermore, to ensure high precision testing, a special testing rig was also developed for testing of long span beams. The description of test models, testing rig features and test results are presented here. For better interpretation of results, a comparison of the test results with a hot rolled section is also presented. The test results have shown that the proposed CFS composite beams are promising both in terms of better structural performance as well as economy.

Cold Flow and Ignition Tests for a 75-tonf Kerosene-Cooled Liquid Rocket Engine Thrust Chamber (75톤급 액체로켓엔진 케로신 냉각 연소실 수류시험 및 점화시험)

  • Kang, Dong-Hyuk;Lim, Byoung-Jik;Ahn, Kyu-Bok;Seo, Seong-Hyeon;Han, Yeoung-Min;Choi, Hwan-Seok
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.05a
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    • pp.25-28
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    • 2010
  • The Cold flow and ignition tests have been performed for a technology demonstration model of 75-tonf liquid rocket engine thrust chamber which was designed and manufactured on the basis of the previous development experience of a 30-tonf liquid rocket engine thrust chamber. The hydrodynamic characteristics of the facility supply pipelines and the filling time of the cooling kerosene were obtained through the cold flow tests. The ignition cyclogram was determinded using the results and the ignition test was successfully carried out. The acquired data and test technique of present ignition test will be used in hot firing tests.

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Effects of Soup Temperature on Hunger, Energy and Nutrient Intake (국의 온도가 공복감, 열량 및 영양소 섭취량에 미치는 영향)

  • 김석영;장희애;김주영;박경민
    • Journal of Nutrition and Health
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    • v.36 no.8
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    • pp.859-869
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    • 2003
  • The purpose of this study was to compare the effects of soup temperature on hunger, energy, and nutrient intake. The hot meal consisted of 400 g of hot beef-vegetable soup (75$^{\circ}C$), Yubu Chobap, Bulgogi, cucumber pickle and radish pickle. The cold meal component were the same as the hot meal except 300 g of water (8$^{\circ}C$) and boiled vegctables (100 g), instead of the hot beef-vegetable soup ot the hot meal. Thirst, core temperature and blood pressure were also measured before and after consumption the test meals in a within-subjects, repeated measures design. 30 women consumed 17% more kilocalories, 13% more protein and lipid and 16% more carbohydrate in the cold meal than in the hot meal. The core temperature at the end of the test meal was higher in the hot meal than in the cold meal. Energy and nutrient intake were inversely correlated with the hunger scores within 1 hour after the hot meal, however those are not related with each other in the cold meal. So hunger feeling might be disturbed in the cold meal. It is concluded that energy and nutrient consumptions were higher in the cold meal, partly because of the distrubed hunger feeling in the cold meal.

A Case of Cold Agglutinin Hemolytic Anemia Complicating Mycoplasma pneumoniae pneumonia in Children (소아에서 Mycoplasma pneumoniae pneumonia에 합병된 한냉응집소 용혈성 빈혈 1례)

  • Jo, Sung Ok;Park, Hyeon Jin
    • Pediatric Infection and Vaccine
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    • v.5 no.2
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    • pp.302-307
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    • 1998
  • Hemolytic anemia due to cold agglutinin disease is a known complication of Mycoplasma pneumoniae infection but is rarely observed, particularly in children. A case of Mycoplasma pneumonia complicated with hemolytic anemia is presented. A 7 year-old girl was adimitted because of fever, cough, sputum and pale appearance. Chest X-ray showed pneumonic consolidation of Rt. upper lobe, lingular division. Laboratory studies disclosed the following values : Hb 5.3g/dL, Hct 11.1%, reticulocyte 2.9%, indirect Coombs test negative, direct Coombs test(monovalent) Anti-C3d positive, Anti-IgG negative, Anti-IgM negative, cold agglutinin titer 1 : 256, mycoplasma antibody titer 1 : 640, total bilirubin 1.0mg/dL. Initial PBS before wanning showed agglutination of red blood cells. The diagnosis of cold agglutinin hemolytic anemia complicating mycoplasma pneumonia was made. And treatment with roxithromycin, prednisolone and avoiding cold exposure was initiated, and complete recovery ensued. We report a case of cold agglutinin hemolytic anemia complicating mycoplasma pneumonia in children.

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Highly Efficient Cold Sputtered Iridium Oxide Films for Polyimide based Neural Stimulation Electrodes

  • Kim, Shin-Ae;Kim, Eui-Tae;Kim, Sung-June
    • Journal of Biomedical Engineering Research
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    • v.30 no.3
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    • pp.199-204
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    • 2009
  • Iridium oxide films (IROFs) have been extensively studied as a material for electrical stimulation of neurons, as iridium oxide has higher charge storage capacity than other metal films. More recently, sputtered iridium oxide film (SIROF) has been studied, because it can be made more conveniently than activated iridium oxide film (AIROF). Typically, the SIROFs are grown at temperatures from 400 to 600 $^{\circ}C$. However, such high temperatures cannot be used when the iridium oxide (IrOx) film is to be deposited on a flexible polymer material, such as polyimide. In this paper, we show that we can still obtain excellent characteristics in SIROFs grown without heating (cold SIROF), by optimizing the growth conditions. We show that the oxygen flow rate is a critical parameter for controlling the surface properties of a cold SIROF. At an oxygen flow rate of 12 seem, the cold SIROF exhibited a charge storage capacity (CSC) of 60 mC/cm$^2$, which is comparable to or better than other published values for iridium oxide films including heated SIROFs. The film produced under these conditions also had the minimum impedance value of all cold SIROFs deposited for this study. A stability test and biocompatibility test also demonstrated the superiority of the optimized cold SIROF.