• Elastomers and Composites
• /
• v.52 no.2
• /
• pp.105-113
• /
• 2017

The curing behavior, mechanical properties, hot-air aging resistance, abrasion properties,thermal properties, etc., of EVM/EPM/APP (ammonium polyphosphate)/DPER (dipentaerythritol)/EG (expandable graphite) and EVM/EPM/ATH (aluminium trihydroxide) flame retarding systems in ethylene vinyl acetate rubber (EVM) blends with EPM (ethylene propylene rubber) were sequentially examined. For both flame retarding systems, the torque values increased with the content of EPM rubber and with the vulcanization time. As the content of EPM rubber increased, the scorch time became shorter, whereas the optimum cure time followed an increasing trend. For the EVM/EPM/APP/DPER/EG flameretarding system, as the content of EPM rubber increased, the hardness did not change,whereas the tensile strength and elongation at break decreased. A hot-air aging resistance test at $150^{\circ}C$ showed that the heat resistance decreased with the EPM content regardless of the kinds and contents of flame retardants. As the EPM content increased, the abrasion rate became higher and the abrasion resistance of the EVM/EPM/APP/DPER/EG flame retarding systems exceeded that of the EVM/EPM/ATH flame retarding counterparts. In comparison with the EVM/EPM/ATH flame retarding systems, the thermal stability of the EVM/EPM/APP/DPER/EG flame retarding system showed an increasing tendency.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.5 no.1
• /
• pp.186-194
• /
• 1997

The objective of this study is to develope knock control algorithms which can increase engine power without causing frequent knock occurrence. A four cylinder spark-ignition engine is used for the experiments to develop knock control algorithms which use block vibration signals. Knock occurrence is detected accurately by using knock threshold values which consider the difference of transmission path of each cylinder. Spark timing is controlled both simultaneously and individually. With the simultaneous control, torque gain is achieved by retarding the spark timing on knock occurrence in propotion to the knock intensity. The individual knock control algorithm results in higher torque gain than the simultaneous knock control algorithm. The knock occurrence frequency of the individual knock control algorithm is about twice the value of the simultaneous knock control algorithm results. Both control algorithms give similar torque gain of about 3% when they are optimized.

• Journal of the Korean Ceramic Society
• /
• v.30 no.2
• /
• pp.131-138
• /
• 1993

The effects of silane coupling agents on the injection molding process were investigated using silicone nitride mixtrues with a binder system containing polypropylene as a major binder (55vol% solid loading). The formation of bonding between silicon nitride powder and coupling agents was confirmed through the analyses of powder surface. The use of coupling agents improved mixing characteristics judged by the torque change during mixing process. the coupling agents also reduced molten viscosity of the mixture considerably, which is a main factor to determine the flow of the mixture. However, the bonding between coupling agents and polymers had a negative effect on the debinding process by retarding the thermal decomposition.

• The KSFM Journal of Fluid Machinery
• /
• v.20 no.2
• /
• pp.47-52
• /
• 2017

In general industry, TFM(turbine flow meters) as measuring instruments having high reliability are widely used in the trade of petroleum and in the measurement of tap water and hot water. The TFM is performed calibration for using in the field and is mainly calibrated at room temperature. Since accuracy of TFM depends on Reynolds number of fluid, TFM is calibrated at same Reynolds number by changing flow rate. Furthermore, the TFM using a fluid of high temperature should have considered for other factors such as the thermal expansion of the parts and characteristics change is unknown changes in the turbine flow meter accordingly. In this paper, two turbine flowmeter are experimentally studied about characteristics change using the facilities which can change fluid temperature from 6 degree celsius to 90 degree celsius. As a result, the turbine flow meter can be calibrated to minimize the error characteristic at a similar temperature and the actual temperature.

• Journal of Advanced Marine Engineering and Technology
• /
• v.38 no.6
• /
• pp.681-687
• /
• 2014

The objective of this work presented here was focused on analysis of in-cylinder combustion characteristic, engine performance, and nitrogen oxides emission characteristic from marine gas oil for propulsion diesel engine of naval vessels and biodiesel with fuel injection timing in a single cylinder diesel engine. In addition, combustion process was analyzed with a high speed camera of marine gas oil and biodiesel fuel. Retarding the fuel injection timing from $BTDC25^{\circ}CA$ to $BTDC5^{\circ}CA$, in cylinder peak combustion pressure was gradually decreased, however, engine torque showed a tendency to increase. The highest nitrogen oxides level was measured at $BTDC15^{\circ}CA$, they were reduced at retarded and advanced condition on the basis of $BTDC15^{\circ}CA$. Comparing with combustion process of marine gas oil and biodiesel fuel at $BTDC5^{\circ}CA$, self-ignition timing of biodiesel fuel included oxygen content was faster than marine gas oil, however, a cautious observation indicates a slightly higher flame intensity for marin gas oil than biodiesel as a diffusion flame is developing.