• Title/Summary/Keyword: Water Rocket

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Atomization Characteristic of F-O-F Triplet Injector for Gas Generator (가스발생기용 F-O-F 충돌형 인젝터 분사특성)

  • Kwon, Sun-Tak;Lee, Chang-Jin;Kim, Seung-Han;Han, Yeoung-Min
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.1
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    • pp.62-68
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    • 2005
  • An injector for fuel rich gas generator was designed and experimentally investigated. Five variations of F-O-F triplet impinging type injector were tested to evaluate spray characteristics with kerosene/water simulant propellant. Test was focused to find the effect of design variables of impinging angle, and impinging distance, on the atomization performance. A mixing efficiency is used to compare droplet distribution and local O/F ratio of each injector in the range of momentum ratio of 0.2~1.3. Test results shows the max value of mixing efficiency locates about the 0.8 in momentum ratio. And the injector with an impinging angle of 45 degree and impinging distance of 6mm shows the very good performance result suitable for fuel rich gas generator. A combustion test will be also conducted with selected injector to verify the spray pattern and mixing efficiency.

Strength Characteristics of Geo-polymer Grout (지오폴리머계 그라우트재의 강도 특성)

  • Lee, Jonghwi;Kim, Seonju;Cha, Kyungsub;Kim, Sunkon;Chun, Byungsik
    • Journal of the Korean GEO-environmental Society
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    • v.13 no.4
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    • pp.53-59
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    • 2012
  • In this study, strength and durability of a geo-polymer grout material(HIT) was investigated through unconfined compression strength tests(UCS)), scanning electron microscope(SEM), elution tests, and surface observations. UCS tests showed high initial strength and rapid continuous strength increments when compared to labile wasser glass(LW) and space grouting rocket system (SGR) grout materials, which showed strength reduction after 28 days. The higher strength was also reflected in SEM results which showed calcium silicate hydroxide(C-S-H) gels of the dense hydrate range, indicating higher strength and durability. Additionally, elution tests and grout surface observations showed HIT was in good condition and the decrease in weight was minor when under water for six months. LW and SGR showed the grout surface to be constricted and lower durability due to higher weight increase. These results and observations show HIT to be better suited for coastal structural applications than LW and SGR in long terms of strength and durability.

Effects of Impellers and Floating Ring Seals on Performance of Centrifugal Pumps (임펠러 및 플로팅 링 실이 원심 펌프의 성능에 미치는 영향)

  • Kim, Dae-Jin;Choi, Chang-Ho;Hong, Soon-Sam;Kim, Jin-Han
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.10
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    • pp.1083-1088
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    • 2011
  • The effects of an impeller and floating ring seals on the performance of centrifugal pumps are investigated on the basis of their test results using water. The pumps are single-staged centrifugal pumps developed for 30-ton- and 75-ton-class liquid rocket engines, and are components of a turbopump that supplies propellants (liquid oxidizer and kerosene) to the combustion chamber. The exit width of the impellers and the numbers and exit angles of the impeller blades are found to have influences on the pump heads. In addition, the pumps have different efficiencies according to the gaps between the floating ring seals and the impellers, whereas the pump size seems to have less effect on the efficiency.

Identification and spectral analysis of the CIBER/LRS detected stars

  • Kim, MinGyu;Matsumoto, T.;Lee, Hyung Mok;Arai, T.;Battle, J.;Bock, J.;Brown, S.;Cooray, A.;Hristov, V.;Keating, B.;Korngut, P.;Lee, Dae-Hee;Levenson, L.R.;Lykke, K.;Mason, P.;Matsuura, S.;Nam, U.W.;Renbarger, T.;Smith, A.;Sullivan, I.;Wada, T.;Jeong, Woong-Seob;Zemcov, M.
    • The Bulletin of The Korean Astronomical Society
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    • v.37 no.2
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    • pp.141.1-141.1
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    • 2012
  • CIBER (Cosmic Infrared Background ExpeRiment) is a sounding-rocket borne experiment which is designed to find the evidence of the First stars (Pop.III stars) in the universe. They are expected to be formed between the recombination era at z ~ 1100 and the most distant quasar (z ~ 8). They have never been directly detected due to its faintness so far, but can be observed as a background radiation at around $1{\mu}m$ which is called the Cosmic Near-Infrared Background (CNB). The CIBER is successfully launched on July 10, 2010 at White Sands Missile Range, New Mexico, USA. It consists of three kinds of instruments. One of them is a LRS (Low Resolution Spectrometer) which is a refractive telescope of 5.5 cm aperture with spectral resolution of 20 ~ 30 and wavelength coverage of 0.7 to $2.0{\mu}m$ to measure the spectrum of the CNB. Since LRS detects not only CNB but also stellar components, we can study their spectral features with the broad band advantage especially at around $1{\mu}m$ which is difficult at ground observations because of the atmospheric absorption by water vapor. I identified around 300 stars from observed six fields. If we can classify their spectral types with SED fitting, we can study their physical conditions of the stellar atmosphere as well as making a stellar catalogue of continuous stellar spectrum.

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Introduction to Lunar Oxygen Distribution and Its Extraction Technology (달 표면 산소 분포 및 산소 추출 기술 소개)

  • Kim, Kyeong Ja
    • Korean Journal of Mineralogy and Petrology
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    • v.34 no.1
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    • pp.83-93
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    • 2021
  • NASA has a plan for the Artemis manned lunar mission in 2020. In 2030s, not only America but also other countries are considering to prepare for human to stay on the Moon at least for a month and necessary technology is currently being developed. With this plan, the mostly considered thing is lunar in-situ resource utilization. The most essential resources could be water and oxygen for sustain human life on the Moon. These resources are not supposed to be brought from the Earth, and it is economically sensible if they are obtained from the lunar surface. Because oxygen can be used as both oxidizer and propellent when a rocket departs from a lunar base directly to Mars, technology for extraction method of oxygen resource and its utilization has been being developed worldwide. This paper introduces oxygen distribution on the Moon and major oxygen extraction methods.

Supported Metal Nanoparticles: Their Catalytic Applications to Selective Alcohol Oxidation (금속 나노 촉매를 활용한 선택적 알코올 산화 반응)

  • Hussain, Muhammad Asif;Joseph, Nyanzi;Kang, Onyu;Cho, Young-Hun;Um, Byung-Hun;Kim, Jung Won
    • Applied Chemistry for Engineering
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    • v.27 no.3
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    • pp.227-238
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    • 2016
  • This review article highlights different types of nano-sized catalysts for the selective alcohol oxidation to form aldehydes (or ketones) with supported or immobilized metal nanoparticles. Metal nanoparticle catalysts are obtained through dispersing metal nanoparticles over a solid support with a large surface area. The nanocatalysts have wide technological applications to industrial and academic fields such as organic synthesis, fuel cells, biodiesel production, oil cracking, energy conversion and storage, medicine, water treatment, solid rocket propellants, chemicals and dyes. One of main reactions for the nanocatalyst is an aerobic oxidation of alcohols to produce important intermediates for various applications. The oxidation of alcohols by supported nanocatalysts including gold, palladium, ruthenium, and vanadium is very economical, green and environmentally benign reaction leading to decrease byproducts and reduce the cost of reagents as opposed to stoichiometric reactions. In addition, the room temperature alcohol oxidation using nanocatalysts is introduced.

Technical Trends of Hydrogen Manufacture, Storage and Transportation System for Fuel Cell Vehicle (연료전지자동차용 수소제조와 저장·운반기술동향)

  • Kil, Sang-Cheol;Hwang, Young-Gil
    • Resources Recycling
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    • v.25 no.1
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    • pp.48-59
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    • 2016
  • The earth has been warming due to $CO_2$ gas emissions from fossil fuel cars and a ship. So the hydrogen fuel cell vehicle(FCV) using hydrogen as a fossil fuel alternative energy is in the spotlight. Hyundai Motor Company of Korea and a car companies of the US, Japan, Germany is developing a FCV a competitive. Obtained hydrogen as a by-product of the coke plant, oil refineries, chemical plants of steel mill, coal is reacted with steam at high temperatures, methane gas, manufacture of high purity hydrogen Methane Steam Reforming and hydrogen detachable reforming method using the Pressure Swing Adsorption or Membrane Reforming technical or decomposition of water to produce electricity. Hydrogen is the electronic industry, metal and chemical industries, which are used as rocket fuel, etc. are used in factories, hospitals, home of the fuel Ene.Farm system or FCV. And a method of storing hydrogen is to store liquid hydrogen and a method for compressing normal hydrogen to the hydrogen container, by storing the latest hydride or Organic chemical hydride method is used to carry the hydrogen station. Korea is currently 13 hydrogen stations in place and in operation, plans to install a further 43 places.

A Study on the Vegetables Mentioned in the Bible (성서에 언급된 채소류에 관한 연구)

  • Woo, Ja-Won
    • Journal of the Korean Society of Food Culture
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    • v.22 no.1
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    • pp.1-9
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    • 2007
  • This paper is intended to study what kinds of the vegetables are mentioned in the Bible and how they were used in those days. While one hundred and twenty-eight different plants are mentioned in the Bible, there are today 2,384 plant species in modem Israel, most of which have been introduced in recent centuries. These plants obviously did not exist there in biblical times and were only recently introduced from Australia and South America, respectively. This article will study only the vegetables mentioned in the Bible and known to have existed in the old and new testament times. Since the first book devoted exclusively to biblical botany was that of Levinus Lemmens in 1566, the modem systematic study of biblical plants, began with F. Hasselquist, a student of Linnaeus, the founder of modem botany. In 1928, Immanuel Loew approached the subject differently, reviewing all known data pertaining to biblical plants. His work not only discussed biblical plants, but also plants in later Jewish literature, particularly the Talmud. The British scholar G. E. Post provided a broad field study of modem plants in Palestine, Syria, Lebanon, and Jordan. More recent major treatments of the subject include those of A. and H. Moldenke (1952), M. Zohary (1982), N. Hareuveni (1984), and Y. J. Choi(1996). Today, articles on specific biblical plants listed in the Bible can be found in any number of encyclopedias. This study attempts to provide a synthesis of the work of a number of scholars who studied the vegetables and plants mentioned in the Bible. As a preliminary study on the culture of food in the biblical period, this study has focused on the identity and features of the vegetables of the Bible. In only a limited number of instances, because of the paucity of the informations and the broad and generic descriptions of the plants, we can't be certain about the identification of the vegetables named in the Bible. In many instances the traditions established by the Greek, Aramaic, and English translations are helpful, although sometimes they are misleading. This paper subdivides the vegetables into broad areas, the general vegetables and the flavoring herbs. Vegetables formed very important part of the diet in the biblical times. Two main types were used: those whose nutritious seeds could be easily stored and those which were eaten freshly gathered from gardens. Pulse seeds provided a useful source of vegetable protein, while fresh green vegetables were vitamin rich. Pulses could be eaten boiled, or their dried seeds could be ground up into flour and then made into nutritious soups. Fresh vegetables were eaten either raw or lightly cooked, usually by boiling in water. The general vegetables in the Bible are herbs(garden rocket), cucumber(snake cucumber), watermelon, leeks, chicory, and onions. Also the flavoring herbs in the Bible are rue, dill, cummin, black cummin, frankincense, cinnamon, cassia, myrrh, black mustard, coriander, mint, saffron, ginger grass, syrian hyssop, aloes(eagle wood), manna which have the flavor, aroma, and medical values.

Bioconcentration Factor(BCF) of Perchlorate from Agricultural Products and Soils (농산물과 토양에 대한 퍼클로레이트 함량 평가 및 생물농축계수 산출)

  • Kim, Ji-Young;Kim, Min-Ji;Lee, Jeong-Mi;Kim, Doo-Ho;Park, Ki-Moon;Kim, Won-Il
    • Korean Journal of Environmental Agriculture
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    • v.32 no.3
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    • pp.224-230
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    • 2013
  • BACKGROUND: Perchlorate(${ClO_4}^-$) is an anion that is extremely water-soluble and environmentally stable. It mostly exists in the form of sodium perchlorate, ammonium perchlorate and potassium perchlorate which are used in rocket fuels, propellants, ignitable sources, air bag inflation systems and explosives. Perchlorate can be taken into the thyroid glands and interfere with iodide uptake. The determination of perchlorate in agricultural products is important due to its potential health impact on humans. The objective of this study was to determine the perchlorate concentrations in the samples of various agricultural products and soils. METHODS AND RESULTS: In this study, samples of cereal(Rice, Barley, Corn, Bean), vegetable(Spinach, Lettuce, Sesame, Chives, Chili, Pumpkin, Tomato), fruit(Apple, Pear, Tangerine, Grape) were analyzed for perchlorate contents. Perchlorate concentrations were analyzed by liquid chromatography-tandem mass spectrometry. The results showed that agricultural products respectively contained perchlorate concentrations in the range of : cereals N.D.~$7.46{\mu}g/kg$, vegetables $0.52{\sim}23.06{\mu}g/kg$, fruits $0.19{\sim}2.66{\mu}g/kg$. Bioconcentration factor was in the order of : vegetables > cereals > fruits. Bioconcentration factor was highest follwed by Sesame 37.88, Corn 21.51, Spinach 10.57, Tangerine 4.39, Chives 2.89 and Lettuce 1.90. The recoveries of perchlorate from spiked agricultural products and soils ranged from 87.72~111.26% and 102.09~111.23%. CONCLUSION(S): The health risk assessment results obtained in this study are lower than the RfD(Reference Dose, 0.0007 mg/kg/body weight/day) value as suggested by the Integrated Risk Information System(US IRIS). Our results indicate that, people currently exposed to perchlorate from agricultural products consumption are considered as safe.