의회와 정책 : 위원회 역할의 대두

John Halligan,John Power,robin Miller 한국행정학회 1995 한국행정학회 학술발표논문집 Vol.1995 No.-

의회와 정책 : 위원회 역할의 대두

John Halligan,John Power,Robin Miller 한국행정학회 1995 한국행정학회 학술발표논문집 Vol.1995 No.-

Tensile bond strength of four denture resins to porcelain teeth with different surface treatment

John Power,Mohamed El-Sheikh 대한치과보철학회 2013 The Journal of Advanced Prosthodontics Vol.5 No.4

PURPOSE This study evaluated the bond strength between porcelain denture teeth (Bioblend 43D) and four different polymerized denture resins (Lucitone 199, Palapress, Acron MC, Triad) with and without a bonding agent and after four different types of surface treatment (polished, HF etched, sandblasted, air-abraded). MATERIALS AND METHODS Central incisor porcelain denture teeth were divided into 32 groups of 5 each. Tensile bond strength (MPa) was determined using a testing machine at crosshead speed of 0.5 mm/min. Mean and standard deviation are listed. Data were analyzed by two-way ANOVA. Means were compared by Tukey-Kramer intervals at 0.05 significance level. RESULTS All surface treatment increased bond strength compared to polished surface and the highest bond strength was found with Palapress resin with etched porcelain surface (8.1 MPa). Bonding agent improved the bond strength of all denture resins to porcelain teeth. Superior bonding was found with Palapress and air-abraded porcelain (39 MPa). CONCLUSION Resins with different curing methods affect the bond strength of porcelain teeth to denture bases. Superior bonding was found with auto-polymerized resin (Palapress). Application of ceramic primer and bonding agent to porcelain teeth with and without surface treatment will improve the bond strength of all denture resins to porcelain teeth.

Application of Neural Networks in Aluminum Corrosion

John Powers,M . Masoom Ali 한국데이터정보과학회 2000 한국데이터정보과학회지 Vol.11 No.2

Metal containers represent a situation where a specific metal is exposed to a wide variety of electrolytes of varying degrees of corrosivity. For example, hundreds, if not thousands of different products are packaged in an aluminum beverage can. These products vary in pH, chloride concentration and other natural or artificial ingredients which can effect the type and severity of potential corrosion. Both localized (perforation) and uniform corrosion (metal dissolution without the onset of pitting) may occur in the can. A quick test or series of tests which could predict the propensity towards both types of corrosion would be useful to the manufacturer. Electrochemical noise data is used to detect the onset and continuation of pitting corrosion. Specific noise parameters such as the noise resistance (the potential noise divided by the current noise) have been used to both detect pitting corrosion and also to estimate the pitting severity. The utility of noise resistance and other electrochemical parameters has been explored through the application of artificial neural networks. The versatility of artificial neural networks is further demonstrated by combing electrochemical data with electrolyte properties such as pH and chloride concentration to predict both the severity of both localized and uniform corrosion.

Application of Neural Networks in Aluminum Corrosion

Powers, John,Ali, M. Masoom The Korean Data and Information Science Society 2000 한국데이터정보과학회지 Vol.11 No.2

Metal containers represent a situation where a specific metal is exposed to a wide variety of electrolytes of varying degrees of corrosivity. For example, hundreds, if not thousands of different products are packaged in an aluminum beverage can. These products vary in pH, chloride concentration and other natural or artificial ingredients which can effect the type and severity of potential corrosion. Both localized (perforation) and uniform corrosion (metal dissolution without the onset of pitting) may occur in the can. A quick test or series of tests which could predict the propensity towards both types of corrosion would be useful to the manufacturer. Electrochemical noise data is used to detect the onset and continuation of pitting corrosion. Specific noise parameters such as the noise resistance (the potential noise divided by the current noise) have been used to both detect pitting corrosion and also to estimate the pitting severity. The utility of noise resistance and other electrochemical parameters has been explored through the application of artificial neural networks. The versatility of artificial neural networks is further demonstrated by combing electrochemical data with electrolyte properties such as pH and chloride concentration to predict both the severity of both localized and uniform corrosion.

Effects of Cadmium on Radial Growth and Dry Mass Production of Ectomycorrhizal Fungi

Kim, Chang-Gi,Power, Sally Anne,Bell, John Nigel Berridge The Ecological Society of Korea 2004 Journal of Ecology and Environment Vol.27 No.5

The sensitivity to Cd of three ectomycorrhizal fungi, Paxillus involutus, Suillus bovinus and Rhizopogon subcaerulescens, was assessed and compared in terms of radial growth and dry mass production, using both agar and liquid culture. The radial growth of S. bovinus and R. subcaerulescens was significantly reduced at the lowest concentration (0.1mg Cd/L). The 50% effective concentration (EC$_{50}$) values calculated from radial growth rates of the ectomycorrhizal fungi showed that the sensitivity of the fungi to Cd was greatest in S. bovinus and lowest in R. subcaerulescens. Cadmium addition also significantly decreased dry mass production of the ectomycorrhizal fungi. The sensitivity of the fungi to Cd in terms of dry mass production, was greatest in S. bovinus and lowest in P. involutus. Higher growth rates of P. involutus and melanisation of R. subcaerulescens appeared to contribute to reduced Cd toxicity.

Color stability of bonding resins under accelerated aging

Byung C. Choi(최병철),John M. Powers 대한치과재료학회 1996 대한치과재료학회지 Vol.23 No.1

Color stability of bonding resins under accelerated aging

Choi, Byung C.,Powers, John M. 대한치과기재학회 1996 대한치과재료학회지 Vol.23 No.1

접착용 레진은 법랑질이나 상아질에 충전재를 접착시키기 위하여 이용될 뿐 아니라 레진 수복물 수선이나 glaze시에도 이용될 수 있다. 접착용 레진의 변색은 레진 수복물의 변색에 영향을 미칠 수 있다. 이 연구에서는 가속시효에 따른 12종의 접착용 레진(PR, DT, AB, OB, BI, PB, ST, SB, HQ, GL, AL, ID)의 색안정도를 평가하였다. 각각 5개의 시편(직경 10mm, 두께 1mm)을 제작하여 Ci35 Weather-Ometer을 이용하여 450KJ/㎡의 자외선 조사를 가속시효하였다. 반사 분광분석계를 이용하여 시편의 가속시효 전과 후의 spectral reflectance를 측정하였다. 백색판을 배경으로 0.01mm, 0.1mm, 1mm 시편의 spectral reflectance를 Kubelka 방정식을 이용하여 계산하고, 표준광원 A에 대한 CIE L??a??b?? 값을 구하여 가속시효에 따른 변색도 (△E??)를 구하였다. 가속시효 후 0.01mm 시편에서 변색은 거의 나타나지 않았고, 0.1mm 시편의 △E??는 0.07부터 4.86이었으며, 1mm 시편은 OB, BI, PB를 제외하고는 심하게 변색되었다. 일반적으로 접착용 레진은 가속시효 후 노랗게 변색되고 명도는 감소하였다.

Tensile bond strength of four denture resins to porcelain teeth with different surface treatment

El-Sheikh, Mohamed,Powers, John The Korean Academy of Prosthodonitics 2013 The Journal of Advanced Prosthodontics Vol.5 No.4

PURPOSE. This study evaluated the bond strength between porcelain denture teeth (Bioblend 43D) and four different polymerized denture resins (Lucitone 199, Palapress, Acron MC, Triad) with and without a bonding agent and after four different types of surface treatment (polished, HF etched, sandblasted, air-abraded). MATERIALS AND METHODS. Central incisor porcelain denture teeth were divided into 32 groups of 5 each. Tensile bond strength (MPa) was determined using a testing machine at crosshead speed of 0.5 mm/min. Mean and standard deviation are listed. Data were analyzed by two-way ANOVA. Means were compared by Tukey-Kramer intervals at 0.05 significance level. RESULTS. All surface treatment increased bond strength compared to polished surface and the highest bond strength was found with Palapress resin with etched porcelain surface (8.1 MPa). Bonding agent improved the bond strength of all denture resins to porcelain teeth. Superior bonding was found with Palapress and air-abraded porcelain (39 MPa). CONCLUSION. Resins with different curing methods affect the bond strength of porcelain teeth to denture bases. Superior bonding was found with auto-polymerized resin (Palapress). Application of ceramic primer and bonding agent to porcelain teeth with and without surface treatment will improve the bond strength of all denture resins to porcelain teeth.

A Behavior Model of Physicians Within the Framework of Leisure versus Output Theory of Labor Supply

Kong Kyun Ro,John A . Powers 한국경제학회 1976 經濟學硏究 Vol.24 No.1