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Controlling on Attraction Forces of Water Droplets on Surfaces of Polypropylene Nanocomposites
Ahmed Thabet Mohamed,Khaled Ebnalwaled Abdelfattah Ahmed 한국전기전자재료학회 2018 Transactions on Electrical and Electronic Material Vol.19 No.5
In this work, Sol gel method was used to prepare polypropylene nanocomposites; some diff erent types of the nanoparticles(clay, ZnO, SiO 2 and TiO 2 ) and diff erent concentration (1, 5 and 10 wt%) were used to control on the attraction forces of waterdroplets on surfaces of polypropylene nanocomposites. The prepared polypropylene nanocomposites were characterized byFTIR, SEM, dielectric constant, contact angle, wetting energy, spreading coeffi cient and work of adhesion measurements. Experimental results deduced that clay and ZnO nanoparticles reduce the dielectric constant of polypropylene, while SiO 2and TiO 2 increase this value. It has been reported that the wettability of the prepared nanocomposites is reduced by increasingcertain nanoparticles ratio, which indicate the ability of the obtained nanocomposites for packaging and battery casesapplications.
Subtractive versus additive indirect manufacturing techniques of digitally designed partial dentures
Ahmed Mamdouh Snosi,Shaimaa Mohamed Lotfy,Yasmine Galaleldin Thabet,Marwa Ezzat Sabet,Fardos Nabil Rizk 대한치과보철학회 2021 The Journal of Advanced Prosthodontics Vol.13 No.5
PURPOSE. The purpose of this in vitro study was to evaluate the accuracy of digitally designed removable partial denture (RPD) frameworks, constructed by additive and subtractive methods castable resin patterns, using comparative 3D analysis. MATERIALS AND METHODS. A Kennedy class III mod. 1 educational maxillary model was used in this study. The cast was scanned after modification, and a removable partial denture framework was digitally designed. Twelve frameworks were constructed. Two groups were defined: Group A: six frameworks were milled with castable resin, then casted by the lost wax technique into Co-Cr frameworks; Group B: six frameworks were printed with castable resin, then casted by the lost wax technique into Co-Cr frameworks. Comparative 3D analysis was used to measure the accuracy of the fabricated frameworks using Geomagic Control X software. Student’s t-test was used for comparing data. P value ≤ .05 was considered statistically significant. RESULTS. Regarding the accuracy of the occlusal rests, group A (milled) (0.1417 ± 0.0224) showed significantly higher accuracy than group B (printed) (0.02347 ± 0.0221). The same results were found regarding the 3D comparison of the overall accuracy, in which group A (0.1501 ± 0.0205) was significantly more accurate than group B (0.179 ± 0.0137). CONCLUSION. In indirect fabrication techniques, subtractive manufacturing yields more accurate RPDs than additive manufacturing.
Ahmed. M. El-Khatib,ABOUZEID. A. THABET,MOHAMED. A. ELZAHER,MOHAMED. S. BADAWI,BOHAYSA. A. SALEM 한국원자력학회 2014 Nuclear Engineering and Technology Vol.46 No.2
The present work used the efficiency transfer method used to calculate the full energy peak efficiency (FEPE) curves ofthe (2"*2" & 3"*3") NaI (Tl) detectors based on the effective solid angle subtended between the source and the detector. Thestudy covered the effect of the self attenuation coefficient of the source matrix (with a radius greater than the detector's radius)on the detector efficiency. 152 An Eu aqueous radioactive source covering the energy range from 121.78 keV up to 1408.01keV was used. In this study an empirical formula was deduced to calculate the difference between the measured and thecalculated efficiencies [without self attenuation] at low and high energy regions. A proper balance between the measured andcalculated efficiencies [with self attenuation] was achieved with discrepancies less than 3%, while reaching 39% forcalculating values [without self attenuation] due to working with large sources, or for low photon energies.
El-Khatib, Ahmed M.,Thabet, Abouzeid A.,Elzaher, Mohamed A.,Badawi, Mohamed S.,Salem, Bohaysa A. Korean Nuclear Society 2014 Nuclear Engineering and Technology Vol.46 No.2
The present work used the efficiency transfer method used to calculate the full energy peak efficiency (FEPE) curves of the (2"*2" & 3"*3") NaI (Tl) detectors based on the effective solid angle subtended between the source and the detector. The study covered the effect of the self attenuation coefficient of the source matrix (with a radius greater than the detector's radius) on the detector efficiency. $^{152}$ An Eu aqueous radioactive source covering the energy range from 121.78 keV up to 1408.01 keV was used. In this study an empirical formula was deduced to calculate the difference between the measured and the calculated efficiencies [without self attenuation] at low and high energy regions. A proper balance between the measured and calculated efficiencies [with self attenuation] was achieved with discrepancies less than 3%, while reaching 39% for calculating values [without self attenuation] due to working with large sources, or for low photon energies.