• Nuclear Engineering and Technology
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• v.29 no.1
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• pp.45-57
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• 1997

The direct contact condensation phenomenon, which occurs when steam is injected into the subcooled water, has been experimentally investigated. Two plume shapes in the stable condensation regime are found to be conical and ellipsoidal shapes depending on the steam mass flux and the liquid subcooling. Divergent plumes, however, are found when the subcooling is relatively small. The measured expansion ratio of the maximum plume diameter to the injector inner diameter ranges from 1.0 to 2.3. By means of fitting a large amount of measured data, an empirical correlation is obtained to predict the steam plume length as a function of a dimensionless steam mass flux and a driving potential for the condensation process. The average heat transfer coefficient of direct contact condensation has been found to be in the range 1.0~3.5 ㎿/$m^2$.$^{\circ}C$. Present results show that the magnitude of the average condensation heat transfer coefficient depends mainly on the steam mass fin By using dynamic pressure measurements and visual observations, six regimes of direct contact condensation have been identified on a condensation regime map, which are chugging, transition region from chugging to condensation oscillation, condensation oscillation, bubbling condensation oscillation, stable condensation, and interfacial oscillation condensation. The regime boundaries are quite clearly distinguishable except the boundaries of bubbling condensation oscillation and interfacial oscillation condensation.

• Restorative Dentistry and Endodontics
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• v.23 no.2
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• pp.607-617
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• 1998

The purpose of this study was to evaluate the apical sealing ability of lateral condensation method, vertical condensation method, and MicroSeal obturation system. Sixty-four extracted anterior teeth were instrumented to #40 using Profile. Three groups of 20 teeth were obturated by lateral condensation technique, vertical condensation technique, and and MicroSeal obturation system. Control group were not obturated. Teeth were immersed in resorcinol-formaldehyde resin for 5 days at $4^{\circ}C$, and the resin was allowed to polymerize completely for 4 days at room temperature. Teeth were ground horizontally at 1,5mm(level 1), 2.5mm(level 2), and 3.5mm(level 3) from the anatomic apex and examined with a stereomicroscope at X40 magnification. The photographs were taken a at X40 magnification of the filling in each level and scanned. The leakage area, which was filled with the resin, was measured at each of the three levels. Each ratio of leakage was evaluated by calculating the ratio of thearea of the resin to the total area of the canal and was analyzed statistically. The results were as followed: 1. Vertical condensation group had significantly higher percentage of the area which was obturated by gutta percha than other two technique at each level. 2. At the level 1, there was the greatest leakage in the lateral condensation group, but there was no statistically significant(P>0.05) 3. At the level 2, there was the least leakage in the MicroSeal group, and the most leakage in the lateral condensation group. There was statistically significant difference between the MicroSeal group and the lateral condensation group(P<0.05). 4. At the level 3, there was least leakage in the vertical condensation group, and the most leakage in the lateral condensation group. There was statistically significant difference between the vertical condensation group and the lateral condensation group(P<0.05).

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.559-564
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• 1998

The film condensation models in RELAP5/MOD3.1 and RELAP5/WOD3.2 are assessed with the data experiment performed in the scaled down condensation experimental facility with a single vertical tube inner diameter 46 mm in the range of pressure 0.1∼7.5 Mpa for the PSCS(Passive Secondary Condenser System) Both MOD3.1 and MOD3.2 don't shows any reliable predictions the experimental data The RELAP5/MOD3.1 overpredicts the heat transfer coefficients experiment, whereas the RELAP5/MOD3.2 underpredicts those data it is recommended that the film condonation model in RELAP5/MOD3.2 should be modified to hue a larger heat transfer coefficient than those the present model to give the reliable predictions.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.3
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• pp.230-238
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• 2003

R407C is considered as alternative refrigerant of R22 for air conditioners. Experimental investigation is made to study the condensation heat transfer characteristics of slit fin-tube heat exchanger using alternative refrigerant, R407C. Experiments are carried out at condensation pressure of 2110 kPa and 1943 kPa with the degree of superheat of 1$0^{\circ}C$ and mass flux varying from 150 to 250 kg/$m^2$s for refrigerant side. The inlet air condition is dry bulb temperature of 35$^{\circ}C$, relative humidity of 50% and air velocity varying from 0.8 to 1.6 m/s. Experiments show that pressure drop gets smaller at a higher condensation pressure especially when condensation pressure is raised from 1943 to 2110 kPa. Heat transfer rate gets smaller at a lower condensation pressure in the range of experimental condition.

• Restorative Dentistry and Endodontics
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• v.27 no.3
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• pp.277-283
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• 2002

The purpose of this study is to evaluate the two warm gutta-percha filling techniques by measuring the weight changes of resin blocks before and after canal filling in ribbon shaped canal. Simulated ribbon shaped root canals in 30 transparent resin blocks were instrumented to #40 using .06 taper Profile. 15 resin blocks were obturated with gutta-percha using cold lateral condensation. Warm lateral condensation using the Endotec II was then accomplished on the same 15 blocks. Another 15 resin blocks were obturated using the System B. All canals were obturated without sealer. The resin blocks were weighed after canal preparation and after each subsequent obturation, and then weight changes of the resin blocks were calculated The results were as follows. 1. Warm lateral condensation using Endotec II and continuous wave of condensation using System B produced a denser obturation of gutta-percha compared with conventional cold lateral condensation (p<0.01). 2. There was no significant difference between warm lateral condensation and continuous wave condensation. In conclusion, the warm gutta-percha condensation techniques like warm lateral condensation and continuous wave condensation can be expected to bring favorable canal obturation results in ribbon shaped canals.

• Restorative Dentistry and Endodontics
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• v.20 no.2
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• pp.671-684
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• 1995

The purpose of this study was to compare the apical sealing ability, overfilling and obturation of lateral canals using two gutta-percha techniques: Thermafil obturators and cold lateral condensation. Eighty numbered epoxide blocks with one major and five lateral canals were divided into four experimental groups and obturated according to experimental groups. Four experimental groups were as follows: Group 1 : Filling with Thermafil plastic obturators and sealer(ThermaSeal) Group 2 : Filling with Thermafil plastic obturators only, without sealer(ThermaSeal) Group 3 : Fillng using lateral condensation with sealer(AH-26) Group 4 : Fillng using lateral condensation without sealer(AH-26) All the blocks were stored in 100% relative humidor at room temperature for 7 days. Each block was placed in centrifuge tube filled with India ink, and then centrifuged for 20 minutes at 3,000 rpm. Apical leakage was measured from the apical foramen to the most coronal level of dye penetration in millimeter under a stereoscope. The length of gutta-percha and sealer in each of the lateral canals was measured, too. The presence or absence of overfilling of gutta-percha and sealer was recorded. The data was analyzed by one-way ANOVA. The obtained results were as follows: l. Apical dye leakage was almost: not occurred in Group Willed with Thermafil and sealer) and Group 3(filled using lateral condensation with sealer), and there was no significant difference in linear leakage between two groups(p>0.01). 2. In both Thermafil and lateral condensation groups, linear leakage of Group I, 3(filled with sealer) was less than that of Group 2, 4(filled without sealer), and there was no significant difference in linear leakage between Group 1, 2, 3(p> 0.01). 3. Overfilling during obturation of Group 1, 2(filled with Thermafil) was more than Group 3, 4(filled using lateral condensation), and there was no significant difference between groups(p> 0.05). 4. Groups filled with Thermafil had significantly more gutta-percha than groups filled using lateral condensation in all lateral canals(p <0.01), the total length of gutta-percha and sealer found in all lateral canals were similar in Group 1 and Group 3.

• Archives of Pharmacal Research
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• v.15 no.1
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• pp.1-4
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• 1992

4-Acetylantipyrine 1 underwent condensation with 4-formyl-antipyrine 2 to give 3. Condensation of either 3 with 1 or 1 with 2 in a molar ratio of (2 :1) afforded 4. Cyclization of 4 in the presence of PPA and ammonium acetate or 4-aminoantipyrine in the presence of glacial acetic acid gave 5-6 respectively. Claisen condensation of 1 with ethyl acetate and diethyl oxalate afforded compounds 8-10. The reaction of 1 and 2 with indole in ethanol/conc. hyddrochloric acid was also investigated.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.3
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• pp.303-314
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• 1998

In this study, the performance of a multi-stage condensation heat pump was examined. Computer simulation programs were developed for 1-stage, 2-stage, and 3-stage heat pumps and R11, R123, R141b were tested as working fluids. The results showed that coefficients of performance(COPs) of an optimized 3-stage condensation heat pump are 25∼40% higher than those of a conventional 1-stage heat pump. The increase in COP, however, differed among the fluids tested. The improvement in COP largely stems from the decrease in average LMTD values in the condensers of the multi-stage system. For the 3-stage condensation heat pumps, optimized UA values of three condensers were determined to be 30∼40% of the UA value of the total condenser regardless of the working fluid. When the amount of cooling water entering into the intermediate and high-stage subcoolers is roughly 10% of the total condenser cooling water respectively, the optimum performance was achieved for the 3-stage condensation heat pump.

• YAKHAK HOEJI
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• v.26 no.2
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• pp.111-116
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• 1982

The behavior of the 5-phenylhydantoin (5-phenyl-2, 4-imidazolidinedione) ring in the aminomethylation reaction was studied in order to determine the orientation of this substitution. In case of monoaminomethylation, 3-morpholinomethyl-5-phenylhydantoin (or 3-piperidinomethyl-5- phenylhydantoin) was synthesized by the condensation of 5-phenylhydantoin with one mole of morpholine (or piperidine) and one mole of formaldehyde. 1, 3-Dimorpholinomethyl- 5-phenylhydantoin was obtained in the attempted condensation of 5-phenylhydantoin with two moles of morpholine and two moles of formaldehyde. Despite the close resemblance to morpholine the attempted condensation of 5-phenylhydantoin with piperidine and formaldehyde under reflux gave no expected 1, 3-dipiperidinomethyl -5-phenylhydantoin. In case of diaminomethylation using piperidine and formaldehyde, only 3, 5-dipiperidinomethyl-5-phenylhydantoin was formed.

• Journal of Dental Rehabilitation and Applied Science
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• v.18 no.3
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• pp.179-184
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• 2002

To compare surface roughness in various porcelains and know effects of condensation, We used Ceramco dentin porcelain, Creation dentin porcelain, Creation margin porcelain, Vintage margin porcelain, Vintage dentin porcelain, and Vita dentin porcelain, and built up the powders with condensation or not, and then fired according to the instructions with porcelain furnace( Dekema, Germany ). We polished the samples step by step using the porcelain adjustment kit( Shofu Inc., Japan ), and then measured, compared and analysed Ra, Rz, and Rmax with Surftest SV-400( Mitutoyo Co., Japan ). 1. With condensation, roughness is significantly increased in Ceramco dentin porcelain (p<0.05) and decreased in Vita dentin porcelain(p<0.05). 2. In Ra, Vita dentin porcelain is significantly the roughest and Creation margin porcelain is rougher than others in no condensation, (p<0.05), and there is no difference under condensation. 3. In Rz, Vita dentin porcelain is significantly the roughest and Creation margin porcelain is rougher than others in no condensation, and Creation margin porcelain is significantly the roughest and Creation dentin porcelain is rougher than others under condensation(p<0.05). 4. In Rmax, Vintage dentin porcelain is significantly the roughest and Creation margin porcelain is rougher than others in no condensation, and Creation margin porcelain is significantly the roughest than others under condensation(p<0.05).