Numerical simulations and experiments have been carried out to meet the next IMO(International Maritime Organization) Tier2 NOx regulations, which would be determined to reduce about 19-2 1% ofthe current limit for medium-speed diesel engine. The selected paraineters in this study are piston bowl shape, fuel iajection nozzle configuration and fuel iniection rate. The behavior of spray and combustion phenomena in diesel engine was examined by the three-dimensional FIRE code. As a droplet breakup model, the wave breakup model was used. In order to predict spray characteristics accurately in the wide range ofambient gas densitM the model constant Bi with respect to breakup time was set as a functien of ambient gas density p, Bi=1.4239xp+O.2093. The spray visualization experiment was perforrned in the constant-volume high-pressure chamber to clarify the numerieal results on the spray characteristics of the spray angle and penetration. The fuel iajection rig test was perfbrmed to know the fuel irijection rate prQfile as an input data fbr the numerical analysis by using Bosch-tube irijection rate metes, The computational results fbr the two different nozzle configurations were verified with the experimental data on the cytinder pressure, fuel consumption and NOx formation through adjustment of some model constants at 50% load, The effects of fuel iojection nozzle, piston bowl and fuel iajection rate on the engine perfbrmance were investigated to find the optimum parameters on NOx control. Finally, 23.7% NOx reduction could be achieved with O,71% deterioration in fuel consumption to meet the next IMO Tier2 regulations.

Ethanolic tetracarbonylhydridoferrate combined with adipaldehyde is very efficient for the selective transformation of an amino group into perhydroazepine. A large variety of both aliphatic and aromatic amines react with adipaldehyde in the presence of tetracarbonylhydridoferrate at room temperature and carbon monoxide to give the corresponding N‐alkyl‐ and N‐arylperhydroazepines in good to excellent yields.

Mtmerical simulations and erperimentshave been carried out to investigate the etilect ofjuel itv'ection nozales on the combustion and NOx formation processes in medium-speed marine diesel engines. SPray and combustion phenomena were examined numerically usingFl/RE code. PPZive breakup and Zeldovich modlels were adopted to describe the atomization characteristics and IVCix formation processes. spray visualization erperiment was pecformed in the constant-volume highpressure chamber to verCtv the numerical results on the spray characteristics such as spray angie and spray tip penetration. nme-resolved spray behaviors were captured by high-speed digital camera and analyzed to extract the injbrmation on the spray parameters. Mtmerical analysis oj' juel injection system was also pet:formed to get theprqfiles ctLfitel itv'ection rate, which should be given as an imput datafor the combustion analysis.IVItmerical results were verijied with experitnental clata such as cylinderpressure, R()HR (ZRate ofHleat Releasel and NOx emission. FinalCM the efiZicts qifitel injection nozzles on the enginepel;ibrmance were investigatednumerically to ,find the optimum nozzleparameters such as.fiiel injection angle, nozzle hole diameter and number qf-nozzle holes. From this stuciji the optimumjuel injection nozzle (}iozzle hole diameter, O.32 mm, number ofnozzle holes, 8 andjuel injection angle. 148 Y wasseleeted to reduce beth the.fbel consumption and IVOx emission. 7he reasonfor this selection could be explained.fi'omthe highestjuei-air mixing in the earlyphase ofinjection due to the longest spray tippenetration and the highest heat release rate oj}er j9O A 1:DC due to the increased injection duration.

The CFT (Concrete Filled steel Tubes) column-footing connection is cast-in-place embedded type which provides simple construction procedure, low cost, and superior structural performance. In this study, CFT column-footing connection of modular pier is proposed and structural performance is evaluated by experimental tests. To evaluate structural performance of the CFT column-footing connection, a series of experimental tests were performed for the 4 specimens with different embedded depth. As a result of the quasi-static test, the specimen with 0.6D (0.6 times the outside diameter of steel tube) embedded depth showed relatively low ductility than other specimens with larger embedded depth due to cone failure of base concrete occurred during the lower loading step. On the contrary, cone failure of the base concrete was not observed in the specimens with larger embedded depth than 0.9D, but typical flexural failure in lower part of CFT column was observed. With the analyses of force-displacement curve, displacement ductility, and energy dissipation capacity, it is concluded that the rational range of embedded depth of the CFT column-footing connection is from 0.9D to 1.2D in view of good seismic performance.