• Journal of Environmental Science International
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• v.14 no.10
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• pp.919-928
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• 2005

This study introduces the development of new supercritical water oxidation(SCW)(multiple step oxidation) to destruct recalcitrant organic substances totally and safely by using sodium nitrate as an oxidant. This method has solved the problems of conventional SCW, such as precipitation of salt due to lowered permittivity, pressure increase following rapid rise of reaction temperature, and corrosion of reactor due to the generation of strong acid. Destruction condition and rate in the supercritical water were examined using Polyvinyl Chloride(PVC) and ion exchange resins as organic substances. The experiment was carried out at $450^{\circ}C$ for 30min, which is relatively lower than the temperature for supercritical water oxidation $(600-650^{\circ}C)$. The decomposition rates of various incombustible organic substances were very high [PVC$(87.5\%)$, Anion exchange resin$(98.6\%)$, Cationexchange resin$(98.0\%)$]. It was observed that hetero atoms existed in organic compounds and chlorine was neutralized by sodium (salt formation). However, relatively large amount of sodium nitrate (4 equivalent) was required to raise the decomposition ratio. For complete oxidation of PCB was intended, the amount of oxidizer was an important parameter.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.275-281
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• 2001

While basic input parameters for the performance and noise of axial fan are flow rate, pressure rise, rotating speed, and fan diameter, the geometric parameters of blade are sweep angle, solidity, and camber angle. The sweep angle does not affect fan performance much, but on fan noise significantly. Solidity and camber angle are very critical design parameters acting on the fan performance directly. The solidity and camber angle are closely related, therefore they have to be carefully determined for the low-noise and high-performance fan. In This paper, different design points are selceted and also geometric parameters are deliberately changed for the comparison of fan noise. As a result, at the same performance, the input rotational speed affects radiated noise more significantly than others. When solidity and camber angle are increased more than those by iDesignFan／sup TM／ program, more noise is experienced. The blade sweep method and blade numbers at same solidity are observed to results in different levels of performance and noise.

• International Journal of Aeronautical and Space Sciences
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• v.16 no.4
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• pp.571-580
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• 2015

In this paper, a computational study was conducted in order to investigate the rotor blade sweep effect on the aerodynamics of a small axial supersonic impulse turbine stage. For this purpose, three-dimensional unsteady RANS simulations have been performed with three different rotor blade sweep angles ($-15^{\circ}$, $0^{\circ}$, $+15^{\circ}$) and the results were compared with each other. Both NTG (No tip gap) and WTG (With tip gap) models were applied to examine the effect on tip leakage flow. As a result of the simulation, the positive sweep model ($+15^{\circ}$) showed better performance in relative flow angle, Mach number distribution, entropy rise, and tip leakage mass flow rate compared with no sweep model. With the blade static pressure distribution result, the positive sweep model showed that hub and tip loading was increased and midspan loading was reduced compared with no sweep model while the negative sweep model ($-15^{\circ}$) showed the opposite result. The positive sweep model also showed a good aerodynamic performance around the hub region compared with other models. Overall, the positive sweep angle enhanced the turbine efficiency.

• Journal of the Korean Society of Industry Convergence
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• v.18 no.4
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• pp.207-215
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• 2015

Since the oil shock of 1970's there was a strong upward tendency for the use of the high viscosity and poorer quality fuels. Therefore the misfiring engine occurs due to the decrease of quantity injected for lean burn and emission control in CI diesel engine. In this study, it is designed and used the test bed which is installed with turbocharger and intercooler. In addition to equipped using CRDI by controlling injection timing with mapping modulator, it has been tested and analyzed the engine performance, combustion characteristics, and emission as operating parameters.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.6
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• pp.571-579
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• 2009

For the flow analysis of reactive compressible media involving energetic materials and metallic confinements, a Hydro-SCCM (Shock Compression of Condensed Matter) tool is developed for handling multi-physics shock analysis of energetics and inerts. The highly energetic flows give rise to the strong non-linear shock waves and the high strain rate deformation of compressible boundaries at high pressure and temperature. For handling the large gradients associated with these complex flows in the condensed phase as well as in the reactive gaseous phase, a new Eulerian multi-fluid method is formulated. Mathematical formulation of explosive dynamics involving condensed matter is explained with an emphasis on validating and application of hydro-SCCM to a series of problems of high speed multimaterial dynamics in nature.

• Journal of the Korean Institute of Navigation
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• v.7 no.2
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• pp.47-63
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• 1983

In this paper, we have investigated the tidal characteristics of the Nakdongpo estuary. We have carried out the analysis of harmonic constant with the use of the recorded data on tidal level at the Gadeong Do tide station and analyzed the flow velocity data obtained by ourselves at two points in the Nakdongpo estuary. In addition, we have analyzed the variation of the mean-sea level. Typical items of the characteristics we have found are; (1) The principal harmonic constants and non-harmonic constants are shown in table 2. (2) Tide in this area shows the semidiurnal inequality. (3) The mean-sea level is shown to be depressed at the rate of about 1cm to the rise of 1 mbar of the atmospheric pressure. (4) (i) At $K_2$ point, The E-W component of the velocty reveals the nature of progressive waves. The N-S component reveals the nature of stationary waves. (ii) At $K_3$ point, The E-W component shows the characteristics of progressive waves to some degree. The N-S component shows a weak hint of stationary waves. (5) At $K_2$ point, S-component is predominant due to the flow of river. At $K_3$ point, E-component is predominant due to the Tsushima current.

• Biomolecules & Therapeutics
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• v.2 no.4
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• pp.347-360
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• 1994

The general and some pharmacological actions of DWP 301 were investigated in animals and the following results were obtained. In central nervous system, DWP 301 had no effects on the pentobarbital induced anaesthesia, rotarod test, traction test, analgesic action, anticonvulsant action in mice and body temperature in rat. But DWP 301 showed a little decrease of locomotor activity at a dose of 3,000 mg/kg. From these results, DWP 301 was considered to have little pharmacological effect on the central nervous system. Furthermore, DWP 301 had no influences on the normal blood pressure and heart rate. DWP 301 showed no effect on the isolated guinea pig ileum, trachea, right atrium, and nonpregnant rat uterus. But, in the isolated guinea pig vas deference, DWP 301 had showed inhibitory effect on the contractions produced by norepinephrine. DWP 301 showed rise of gastric juice pH and decrease of urine volume. Also, DWP 301 had no effect on the gastrointestinal motility and blood aggregation. From these results, it is concluded that the general pharmacological effect of DWP 301 are similar to or weaker than M and AGA.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1997.11a
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• pp.353-360
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• 1997

The modeling on fire safety assessment for a tall and narrow atrium is carried out using a reduced and full scale atrium models based on the performances of flow behavior in and near comer fire and smoke ventilation system. The comer (or wall) effects on the flame behavior considering air entrainment into a flame was evaluated theoretically and experimentally. Temperature, upward velocity, inlet air velocity, and pressure difference between the atrium space and atmosphere were measured systematically in a reduced scale model. The performance of the modeling to estimate temperature rise and natural air ventilation volume was verified based on the experimental results. Smoke filling rate from a model fire source set at the center of a tall and narrow atrium is fastest in the other cases in which fire source set in or near a corner. This suggested that the centering of the fire source is acceptable as the fire source position to assess the fire safety design for a tall and narrow atrium.

• Journal of Fashion Business
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• v.6 no.3
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• pp.84-93
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• 2002

The purpose of this study was to design functional clothing based on the physical characteristics of old women. The subjects of this experiment were 5 healthy old women and 5 college women. While the subjects were exposed to the circumstances of $28{\pm}0.5^{\circ}C$ and local heating at 7 areas (chest, abdomen, back, loin, hand, thigh and instep), their skin temperature, physiological reaction and psychological reaction were determined. The conclusions about the effects of local heating are as follows : 1. Skin temperature before heating was in the order of head-neck> trunk> upper limbs> lower limbs (Group A: old subjects) and head-neck> trunk> lower limbs> upper limbs (Group B: young subjects). 2. The heating pad was attached and detached for 30 minutes each. The sharpest rise and fall were recorded at 5 minutes with the pad on and off. Both groups had great changes in the body parts near trunk. 3. With the pad on and off, both groups showed no change in body temperature, blood pressure, and pulse rate. 4. Concerning the pervasive effects of local heating on whole body skin temperature, loin heating greatly increased other body parts in Group A. In Group B, the effects were large in heating chest, abdomen, back, loin, and thigh. 5. The loin part of old women has the greatest pervasive effect of local body heating.

• Journal of Korean Neurosurgical Society
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• v.38 no.6
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• pp.425-430
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• 2005

Objective : Recently, the survival rate and prognosis of spontaneous intracerebral hemorrhage[S-ICH] has improved, and their enhanced survival has become associated with a consequent rise in the recurrence of S-ICH. The aim of this study is to improve the prevention of recurrent S-ICH. Methods : Between January 1999 and March 2004, we experienced 48 cases of recurrence. We classified the patients into the two groups; a double ICH group and a triple ICH group. We investigated their brain CTs, MRIs, cerebral angiographies, and medical records, retrospectively. Results : Majority of patients had the intervals at least 12 months, and most of patients underwent conservative treatment. The most common hemorrhage pattern of recurrence was ganglionic-ganglionic [basal ganglia - basal ganglia], and the second attack was contralateral side of the first attack in a large percentage of all patients. Prognosis of patients was worsened in recurrent attack. Nearly all patients had medical history of hypertension, and most patients have taken antihypertensive medication at the arrival of emergency room. Conclusion : In treating hypertension for S-ICH patients, we stress that blood pressure must be thoroughly controlled over a long period of time.