• Journal of Korean Society of Water and Wastewater
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• v.20 no.4
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• pp.559-571
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• 2006

The overall objective of this research was to find out the interrelation of coagulant and organic matter during rapid mixing process and to identify the change of organic matter by mixing condition and to evaluate the effect of coagulation pH. During the coagulation, substantial changes in dissolved organics must be occurred by coagulation due to the simultaneous formation of microflocs and NOM precipitates. Increase in the organic removal efficiency should be mainly caused by the removal of microflocs formed during coagulant injection. That is, during the mixing period, substantial amount of dissolved organics were transformed into microflocs due to the simultaneous formation of microflocs and NOM precipitates. The results also showed that 40 to 80% of dissolved organic matter was converted into particulate material after rapid mixing process of coagulation. During the rapid mixing period, for purewater, formation of dissolved Al(III) (monomer and polymer) constant by rapid mixing condition, but for raw water, the species of Al hydrolysis showed different result. During the rapid mixing period, for high coagulant dose, Al-ferron reaction increases rapidly. At A/D(Adsorption and Destabilization) and sweep condition, both $Al(OH)_3(s)$ and dissolved Al(III) (monomer and polymer) exist, concurrent reactions by both mechanism appear to cause simultaneous precipitation.

• Journal of Power System Engineering
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• v.6 no.1
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• pp.27-35
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• 2002

In this paper, the effect of oxygen component in fuel on the exhaust emissions has been investigated for direct injection diesel engine. It is tested to estimate change of engine performance and exhaust emission characteristics for the commercial diesel fuel and oxygenate blended fuel which has four kinds of mixed ratio. And, the effects of exhaust gas recirculation(EGR) on the characteristics of NOx emission and brake specific fuel consumption rate have been investigated. Dimethyl carbonate(DMC) contains oxygen component 53.3% in itself, and it is a kind of effective oxygenated fuel of carbonate group that the smoke emission of DMC is reduced remarkably in comparison with commercial diesel fuel, that is, it can supply oxygen component sufficiently at higher loads and speeds in diesel engine. It was found that simultaneous reduction of smoke and NOx was achieved with oxygenated fuel and EGR method.

• Structural Engineering and Mechanics
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• v.59 no.1
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• pp.37-57
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• 2016

Reservoir geomechanics can play an important role in hydrocarbon recovery mechanism. In $CO_2$-EOR process, reservoir geomechanics analysis is concerned with the simultaneous study of fluid flow and the mechanical response of the reservoir under $CO_2$ injection. Accurate prediction of geomechanical effects during $CO_2$ injection will assist in modeling the Carbon dioxide recovery process and making a better design of process and production equipment. This paper deals with the implementation of a program (FORTRAN 90 interface code), which was developed to couple conventional reservoir (ECLIPSE) and geomechanical (ABAQUS) simulators, using a partial coupling algorithm. A geomechanics reservoir partially coupled approach is presented that allows to iteratively take the impact of geomechanics into account in the fluid flow calculations and therefore performs a better prediction of the process. The proposed approach is illustrated on a realistic field case. The reservoir geomechanics coupled models show that in the case of lower maximum bottom hole injection pressure, the cumulative oil production is more than other scenarios. Moreover at the high injection pressures, the production rates will not change with the injection bottom hole pressure variations. Also the FEM analysis of the reservoir showed that at $CO_2$ injection pressure of 11000 Psi the plastic strain has been occurred in the some parts of the reservoir and the related stress path show a critical behavior.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.2
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• pp.1-7
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• 2007

The effect of injector geometries including the injection angle and number of nozzle holes on homogeneous charge compression ignition (HCCI) engine combustion has been investigated in an automotive-size single-cylinder diesel engine. The HCCI engine has advantages of simultaneous reduction of PM and NOx emissions by achieving the spatially homogenous distribution of diesel fuel and air mixture, which results in no fuel-rich zones and low combustion temperature. To make homogeneous mixture in a direct-injection diesel engine, the fuel is injected at early timing. The early injection guarantees long ignition delay period resulting in long mixing period to form a homogeneous mixture. The wall-impingement of the diesel spray is a serious problem in this type of application. The impingement occurs due to the low in-cylinder density and temperature as the spray penetrates too deep into the combustion chamber. A hole-type injector (5 holes) with smaller angle ($100^{\circ}$) than the conventional one ($150^{\circ}$) was applied to resolve this problem. The multi-hole injector (14 holes) was also tested to maximize the atomization of diesel fuel. The macroscopic spray structure was visualized in a spray chamber, and the spray penetration was analyzed. Moreover, the effect of injector geometries on the power output and exhaust gases was tested in a single-cylinder diesel engine. Results showed that the small injection angle minimizes the wall-impingement of diesel fuel that results in high power output and low PM emission. The multi-hole injector could not decrease the spray penetration at low in-cylinder pressure and temperature, but still showed the advantages in atomization and premixing.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.850-858
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• 1997

An antihyperlipidemic effect was observed by intraperitoneal injection of the seaweed Monostroma nitidum extract. Hyperlipidemia was induced by intraperitoneal injection of Triton WR-1339 $(60\;{\mu}g/g-body\;weight)$ into a mouse. Maximum level of blood cholesterol was reached at 20 hours after Triton injection. By simultaneous injection of the M. nitidum extract $(30\;{\mu}g/g-body\;weight)$ with the Triton into each right and left sides of the peritoneal cavity, levels of total cholesterol and low density lipoprotein were decreased to $24\%\;and\;14\%$ compared to Triton injection only. For histochemical changes, hepatic tissues obtained at 40 hours after injection of the Triton and the M. nitidum extract were fixed in fromol-calcium solution. The meshlike cytoplasms disappeared and hapatic plates were recovered in mice injected with the M. nitidum extract. Numbers of lipid drops and cholesterol particles also decreased in the portal space of the hepatic cytoplasm. This indicates that the accumulation of lipid, including cholesterol, caused by Triton was prevented by the antihyperlipidemic effect of extract from the seaweed M. nitidum.

• The Korean Journal of Physiology
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• v.11 no.1
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• pp.21-26
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• 1977

Many cases have been reported that a post spinal headache can be relieved immediately by an epidural injection of saline; and autologous blood also has recently been used successfully instead of saline. The changes of the cerebrospinal fluid pressure in 40 cases were observed in the present study in support of the concept; that a continuous leakage in association with hypovolemia and hypotension of the cerebrospinal fluid is the primary cause of a post spinal headache. Subarachnoid pressure increased immediately with saline injection into the lumber epidural space. A spinal needle was inserted into the subarachnoid space at the level of $L2{\sim}3$ and opening pressure of the cerebrospinal fluid was read. An epidural Tuohy needle was insertad at the$L3{\sim}4$ and 25m1 of saline was injected into the epidural space and the cerebrospinal fluid pressure was read in the sitting position. $\underline{Sitting\;Position:}$ Mean pressure after injection $555{\pm}(110.9)mm\;H_2O$, Pressure rise rise (%) 51.3%, Mean opening pressure $366{\pm}(52.2)mm\;H_{2}O$, $\underline{Lateral\;position:}$ Mean pressure after injection $308{\pm}(70.8)mm\;H_{2}O$, Pressure(%) 86.7%, Mean opening pressure $165{\pm}(42.6)mm\;H_{2}O$. These pressure changes responded almost simultaneously as saline was injected. This pressure rise of 51.3% in the sitting position and 86.7% in the lateral position are clinically very significant. Therefore, it is most possible that the immediate relieve of post, spinal headache by injection of fluid into the epidural space is simultaneous with the increase of the cerebrospinal fluid pressure.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.1
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• pp.92-97
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• 2005

This research is to investigate the effect of the dual coagulant using inorganic coagulants($AICl3{\cdot}6H2O$) and polymer on the coagulant process. Jar-test was conducted by using Kaolin injected raw water. PDA(Photometric Dispersion Analyzer) equipment in order to analyze the size of the particles and the characteristics of the shapes. The change in the rate of sample ores' residual deposited after coagulants were also compared. According to the result derived from this experiment, the concentration of inorganic coagulant reduced 50% and the residual was lower by using dual coagulants compared to using single coagulant. However the dual coagulant required sufficient mixing time, and affected particle characteristics, with the effect of the injection order of coagulants, the simultaneous injection of inorganic coagulant and polymer showed the most effective in the particle removal.

• 한국연소학회:학술대회논문집
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• 2007.05a
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• pp.133-138
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• 2007

Influence of changing combustor pressure on flame stabilization and emission index in the swirl-stabilized flame was investigated The combustor pressure was controlled by suction fan at combustor exit. Pressure index ($P^{\ast}=P_{abs}/P_{atm}$), where $P_{abs}$ and $P_{atm}$ indicated the absolute pressure and atmosphere pressure, respectively, was controlled in the range of $0.7{\sim}1.3$ for each equivalence ratio conditions. The flammable limits of swirl flames were largely influenced by changing combustor pressure and they showed similar tendency with laminar flames. $NO_x$ emission index decreased with decreasing pressure index for overall equivalence ratio conditions. R.m.s. of pressure fluctuations is increased with decreasing combustor pressure. This flame fluctuation caused incomplete combustion , hence CO emission index increased. These oscillating flames were measured by simultaneous $CH{\ast}$ chemiluminescence time-series visualization and pressure fluctuation measurement.

• Journal of the korean Society of Automotive Engineers
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• v.4 no.2
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• pp.58-68
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• 1982

It is well known to diesel engineers that the heat release pattern is one of the most important factors affecting engine performance. Thorough research in heat release pattern has materially helped the progress in high-speed diesel engine development . This paper is based on the research conducted at KAIST and Daewoo Heavy Industry last year. The purpose of this paper is to determine the heat release pattern in combustion chamber of MAN M type, the famous low-noise engine. Thermodynamic cycle simulation was performed using Whitehous-Way's heat release pattern with modified coefficients and Annand's heat transfer model. Instantaneous temperature and pressure of gas in cylinder could be determined by the numerical solution of simultaneous equation of mass conservation, equation of energy conservation, and state equation of ideal gas. Calculated results were compared with measured values in some details emphasizing upon the factors affecting rate of heat release. The agreement was fairly good and revealed why M type should have lower burning velocity at the early part of combustion in spite of high injection rate. Additional results by parametric studies were given in relation to fuel injection conditions for further application to engine development.

• Journal of information and communication convergence engineering
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• v.5 no.3
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• pp.281-284
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• 2007

We have analyzed the short pulse generation using heterodyne techniques. The numerical model for semiconductor lasers under the heterodyne technique is based on the Lang's equation and has been extended in order to take into account the simultaneous injection of the multiple sidebands of the current-modulated laser. The unselected sidebands will affect the optical and RF-spectral characteristics even when the semiconductor laser is locked to the target sidebands.