• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.3
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• pp.53-61
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• 1999

Impinging jets are observed when exhaust gases from missiles or V/STOL aircrafts impinge on the ground, flame deflector, ship deck, etc. The flow shows different patterns according to the nozzle geometry, nozzle-to-plate distance, and plate angle, for example. This paper describes experimental works on the phenomena (pressure distribution, occurrence of stagnation bubble, and so on.) when underexpanded supersonic jets impinge on a perpendicular flat plate using a supersonic cold-flow system, and compares the results with those obtained using a shock tunnel. The flow characteristics for the supersonic cold-flow system were also investigated. Surface pressure distribution of supersonic cold-flow system differed from that of shock tunnel because of water and temperature in the low-pressure chamber. Surface pressure distribution as to underexpanded ratio showed similar patterns together.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.3
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• pp.263-269
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• 2015

Growing concerns regarding air pollution have recently increased the demand for liquefied natural gas (LNG) fueled ships. LNG-fueled ships are equipped with an explosion relief valve in the crankcase to relieve excessive pressure and stop flames from emitting from the crankcase. In this study, a finite element analysis was conducted to evaluate the crankcase relief valve disk spring design using an ANSYS Workbench, v.15. The setting pressure, leak and explosion test performed by european standard EN14797 to evaluate function and mechanical integrity of crankcase relief valve. The tests results indicate that the pressure of the crankcase relief valve is 3.05 bar, with no air leakage at 2.97 bar. Finally, the mechanical integrity of the crankcase relief valve was confirmed through an explosion test in which the valve plate assembly, flame arrester, and other parts were safe from fracturing.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.490-495
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• 2003

In steel-making process of iron and steel industry, the purity and quality of steel can be dependent on the amount of CO contained in the molten metal. Recently, the supersonic oxygen jet is being applied to the molten metal in the electric furnace and thus reduces the CO amount through the chemical reactions between the oxygen jet and molten metal, leading to a better quality of steel. In this application, the supersonic oxygen jet is limited in the distance over which the supersonic velocity is maintained. In order to get longer supersonic jet propagation into the molten metal, a supersonic coherent jet is suggested as one of the alternatives which are applicable to the electric furnace system. It has a flame around the conventional supersonic jet and thus the entrainment effect of the surrounding gas into the supersonic jet is reduced, leading to a longer propagation of the supersonic jet. In this regard, gasdynamics mechanism about why the combustion phenomenon surrounding the supersonic jet causes the jet core length to be longer is not yet clarified. The present study investigates the major characteristics of the supersonic coherent jet, compared with the conventional supersonic jet. A computational study is carried out to solve the compressible, axisymmetric Navier-Stokes equations. The computational results of the supersonic coherent jet are compared with the conventional supersonic jets.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.251-254
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• 2001

In this paper, we analyzed the properties change of electric wire when the thermal stress was applied to NFR-8 and FR-PVC 600[V] wire. Messurement is made of the attenuation of a light beam by smoke accumulating with in a closed chamber due to nonflaming pyrolytic decomposition and flaming combustion. Results are expressed in terms of specific optical density which is derived from a geometrical factor and the measured optical density a measurement characteristic of the concentration of smoke. Referenced documents were ASTM E662 standard test method for specific Ds genalated by solid materials. The furnace control system shall maintain the required irradiance level under steady-state condition with the chamber door closed of $2.5{\pm}0.04[w/cm^{2}]$ for 20 min. According to the results of the smoke density analysis of NFR-8 and FR-PVC the highest decomposition flaming smoke density range of NFR-8 and FR-PVC were 25.2 to 37.5 and 51.1 respectively. Nonflaming smoke density range of NFR-8 and FR-PVC were 100.4 to 112.2 and 126.5 to 398.8. The amount of carbon monoxide generated was found to be much higher in FR-PVC decomposition than in NFR-8 due to incomplete combustion of FR-PVC which has high content of carbon in compound.

• Journal of the Korean Society of Safety
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• v.13 no.3
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• pp.102-111
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• 1998

This study was concerned with the development of a heavy duty rust-converting agent, the function of which is to form metal complex coatings, containing vinyl halide-acrylic terpolymer emulsion, defoamer, emulsifying agent, glass flakes, chelating agent such as gallotannic acid, gallic acid, and pyrogallic acid, and other additives. The resulted emulsion products(Sample No.1~No.5) were characterized through test either in the forms of emulsions, which include Viscosity, Penetration rate, Acidity and Film drying rate test, or in the forms of coated layer on rusty steel substrates by FT-IR, which include hardness, gloss, salt spray, adhesion and flame retardant test. The test results are as follows ; Penetration rate(0.1~0.4 mm/min), Solid content(70%), Acidity (pH 1.8~2.0), Specific gravity(1.30~1.35), Film drying rate(108min, RH 40% ; 150min, RH 80%), Gloss(83~92, incident angle $60^{\circ}$; 88~97, incident angle $85^{\circ}$), Pencil hardness(4H~5H), Adhesion (100/100), Salt spray test(>720Hr), LOI(%) value(38%), Vertical burning test(UL 94-v-l). According to the various performance of specimens show above, the evaluation of the availability of this heavy duty rust-converting agent can be concluded that all the samples(No.1~No.5) are capable of being used in the field of chemical plant and in the hazard areas of fire and explosion potential. It was observed that the properties of sample No.2, especially gloss and hardness, were much better than that of the other samples.

• Fire Science and Engineering
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• v.18 no.2
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• pp.67-72
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• 2004

This study describes to assess combustion characteristics of fiber reinforced plastic (FRP) that is used an elements of building or structure in workplace. The combustion characteristics of the fiber reinforced plastic were carried out using by a Cone Calorimeter according to ISO 5660 standard. As the results of this study, the time to ignition and heat release rate of the fiber reinforced plastic was differ with heat flux of irradiance and content of flame retardant agent. The heat release rate of the fiber reinforced plastic was increased with increasing heat flux of irradiance. The flashover propensity of the fiber reinforced plastic using time to ignition and peak heat release rate was examined according to classification method by R.V. Petrella.

• The Journal of Internal Korean Medicine
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• v.15 no.1
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• pp.176-209
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• 1994

1. The Jung-Sa(正邪) of the Excessive Liver-Symptoms belongs to the eleven symptoms, there are blue face, blue thin fingernail, anger, fancy of larg body, dizziness, eye flame, Bell's palsy, hard swelling pain at braest, side pain going on the belly from the side, side pain and movement at the left side. 2. The Mi-Sa(微邪) of the Excessive Liver-Symptoms belongs to the four symptoms, there are meat in eye, edema in cheek, lack of appetite and diarrhea. 3. The Juk-Sa(賊邪) of the Excessive Liver-Symptoms belongs to the only one symptom, this is nosebleeding. 4. The Hu-Sa(虛邪) of the Excessive Liver-Symptoms belongs to the three symptoms, there are scrotum constraction, strain in belly and constipation. 5. The Sil-Sa(實邪) of the Excessive Liver-Symptoms belongs to the twenty eight symptoms, there are red eye, raised eyes(兩眼上?), spitting blood, sternocostal turgid pain, turgidity in belly, drooping testis, vomiting water acid, sickening, belching, confusion, impatience, frequent forgetfulness, headache, giddness, eye pain, deaf, ringing in the ear, feeling inverse, drying mouth, stuffiness sensation in the chest, chest pain, stuffiness sensation in the belly, bellyache, quadriplegia, spasm of extremities, tremor, alternate spells of fever and chills, high fever and strain in muscle. 6. Those symptoms, Red corner of the eye, red face, swelling on the forehead, stiff-neck and back strong, opisthotonos, constracture of the limbs, vomiting yellow bitter water, speech impediment, epilepsy, depression, strong tongue, different thing in throat, fullness and distention of the gastric region, feeling sick and tenesmus, have no connected with the Excessive Liver-Symptoms(肝實證) 7. The Excessive Liver-Symptoms(肝實證) is connected with the ganjabyoung(肝自病) and Hwa(火) which the pathology is, than because Mock(木) is excessive and Mock-Saeng-Hwa(木生火), the ganjabyoung(肝自病) and Sil-Sa(實邪) are many. 8. There are the sixteen symptoms with the exception of The Excessive Liver-Symptoms(肝實證), because supposed that the scholars in medicine included the union syndroms(合病), the combine syndroms(兼病) and the analysis of symptoms(辨證) in The Analysis of Five Visceral Symptoms. 9. During consideration of the symptoms at the above statements, where are many causes by Gan-Pung(肝風), there is difficult of distinction between the excessive Liver-Symptoms(肝實證) and C.V.A(Cerebral Vascular Attack). Because than NaeKyung(內經) distinguished between the excessive Liver-Symptoms(肝實證) and C.V.A., the future medical specialists connected with the excessive Liver-Symptoms(肝實證) and C.V.A.. 10. An appearance of Sang-Hwa(相火) that the liver possessed is divided into an appearance of Hwa(火), there will be making a study att the more necessary. 11. The cuases of each syndroms are consist of the origins of syndroms, its pathology and the positions where the syndroms appeared, I consider that is the various ways how judge the syndroms except the Five Pathogenic Factors(五邪). 12. If more than study will be achieved in all, the new definition will be standed about the Excessive and Deficient Five Visceral Syndroms(五臟虛實證), I consider this will be the foundation data that study the Oriental Medicine and the important data that is a judgement standard of clininc.

• Applied Biological Chemistry
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• v.26 no.2
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• pp.104-109
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• 1983

Gas chromatographic method for the analysis of phorate(0,0-diethyl S-ethyl-thiomethyl phosphorithioate) and its metabolites in soil and vegetables was studied by using a mixed phase column(10% DC-200+8% Reoplex-400+2% QF-1 on Gas Chrom Q, $1.8{\times}2mm$ i.d, borosilicate glass column). This column can separate completely phorate and its four metabolites except phoratoxon sulfoxide. Retention time of standard mixture ranged 1.8 to 16.1 minutes at column temperature programming from 130 to $200^{\circ}C$ at $5^{\circ}C/min$ and detector sensitivity was also very high(0.05 to 1.05ng). Recoveries from soil and vegetables untreated but fortified with phorate and its three major metabolites at 0.05 and 0.5ppm levels were above 90% for phorate, phorate sulfoxide and phorate sulfone while recovery of phoratoxon metabolite was about 84%.

• Analytical Science and Technology
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• v.30 no.4
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• pp.174-181
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• 2017

Bio-liquid is a liquid by-product of the hydrothermal carbonization (HTC) reaction, converting wet biomass into solid hydrochar, bio-liquid, and bio-gas. Since bio-liquid contains various compounds, it requires efficient sampling method to extract the target compounds from bio-liquid. In this research, fatty acid methyl ester (FAME) in bio-liquid was extracted based on hollow fiber supported liquid phase microextraction (HF-LPME) and determined by Gas Chromatography-Flame Ionization Detector (GC-FID) and Gas Chromatography/Mass Spectrometry (GC/MS). The well-known major components of biodiesel, including methyl myristate, palmitate, methyl palmitoleate, methyl stearate, methyl oleate, and methyl linoleate had been selected as standard materials for FAME analysis using HF-LPME. Physicochemical properties of bio-liquid was measured that the acidity was 3.30 (${\pm}0.01$) and the moisture content was 100.84 (${\pm}3.02$)%. The optimization of HF-LPME method had been investigated by varying the experimental parameters such as extraction solvent, extraction time, stirring speed, and the length of HF at the fixed concentration of NaCl salt. As a result, optimal conditions of HF-LPME for FAMEs were; n-octanol for extraction solvent, 30 min for extraction time, 1200 rpm for stirring speed, 20 mm for the HF length, and 0.5 w/v% for the concentration of NaCl. Validation of HF-LPME was performed with limit of detection (LOD), limit of quantitation (LOQ), dynamic range, reproducibility, and recovery. The results obtained from this study indicated that HF-LPME was suitable for the preconcentration method and the quantitative analysis to characterize FAMEs in bio-liquid generated from food waste via HTC reaction.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.13 no.4
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• pp.173-178
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• 1980

Cercaria larvae of Bacciger harengulae which is parasitic to Meretrix lusoria, rapes japonica and Solen strictus were studied in terms of their morphology and incidence of infection rate. The host bivalves were collected from Naechodo, Okgu-gun during the Period from January to November in 1980. The tail of the cercaria bears 27 pairs of tufts of setae, the tufts being composed of 6 fine rays. Oral sucker, intestine, ventral sucker and a pair of testes are distinctive. The excretory duct bears numerous granules of various size, and the flame-cell arrangement is represented by a formula 2[(3+3)+(3+3)]=24. The cercaria is somewhat similar to the previously known Cercaria pectinata . It is however conformed that present cercaria belongs to Bacciger harengulae. Infection rate showed seasonal variation and host selectivity. Higher infections were observed in Solen strictus, and lower in Meretrix lusoria. Generally, the larger bivalves over 2-3 years old showed the higher infection rate.