Total Fission Cross Sections in Reactions p+^(181)Ta Investigated in Inverse Kinematics at Relativistic Energies

Y. Ayyad,J. Benlliure,E. Casarejos,H. Alvarez-Pol,C. Paradela,D. Perez-Loureiro,D. Tarrio,A. Bacquias,T. Enqvist,V. Fohr,A. Kelic,R. Pleskac,A. Boudard,,K. Kezzar,S. Leray 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23

Total fission cross sections of ^(181)Ta ions colliding with hydrogen atoms at 300, 500, 800, and 1000 A MeV have been measured. The combined use of the inverse kinematics technique with an efficient detection set-up made it possible to determine these cross sections with high accuracy ranging between 8% and 17%. The new data put some light in the controversial results obtained so far and contribute to the understanding of the fission process at high excitation energies.

Surface tension (γLV), surface energy (γSV) and crystal-melt interfacial energy (γSL) of metals

Fathi Aqra,Ahmed Ayyad 한국물리학회 2012 Current Applied Physics Vol.12 No.1

The results of temperature-dependent surface tension calculations of pure liquids aluminium (933e1200 K) and iron (1811e2500 K), in the framework of the theoretical considerations suggested by Eyring, are presented. It is observed that the surface tension decreases linearly with temperature. The calculated surface tension data are fitted as g ¼ 985e0.275(T Tm) and g ¼ 1560e0.387(T Tm) for Al and Fe, respectively. Moreover, the surface tension (gLV) at melting point, surface energy (gSV) and crystal-melt interfacial energy (gSL) are calculated for many metals. The agreement between the calculated and the reported measured values is reasonable.

A new efficient model of quantum image cryptography based on sampled GNEQR storage presentation

Rfifi Saad,Maafiri Ayyad,Chougdali Khalid,Gueddana Amor 한국물리학회 2021 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.78 No.7

To secure the exchange of a facial image, we extract its region of interest to reduce its size by ignoring the unwanted part. Next, we use the GNEQR representation to store it, followed by a sampled quantum encryption circuit using a quantumgate sequence encoded in the quantum package of the MATHEMATICA platform. Our encryption protocol is based on the perturbation of pixel locations per block in the grayscale image as a proposed scrambling method and not their values using the GNEQR representation thanks to an achieved MATLAB script in the context of quantum image processing. A statistical analysis is carried out to prove the mean robustness of our encryption model compared with a recent work.

Sequence stratigraphy and biozonation of the Upper Eocene Anqabiya Formation, Gebel Anqabiya, Egypt

Abdel Galil A. Hewaidy,Haitham M. Ayyad,Mohamed W. Abd El-Moghny,Osama Gameel 한국지질과학협의회 2019 Geosciences Journal Vol.23 No.3

Few studies on bio-sequence stratigraphy of the late Eocene succession in the study area have published so far. Accordingly, an exposed section of the Anqabiya Formation at Gebel Anqabiya along Cairo–Suez district of Egypt, was examined in detail to determine its foraminiferal and nannoplankton assemblages and to produce a sequence stratigraphic classification. We reveal that in this section, foraminifera and calcareous nannoplankton are generally rare, with relatively poor to moderate preservation, an restricted to certain horizons. Nineteen species of planktonic foraminifera and 24 species of calcareous nannoplankton were identified, leading to the classification of two planktonic foraminiferal zones (Globigerinatheka semiinvoluta Zone E14 and Globigerinatheka index Zone E15) and one calcareous nannoplankton zone (NP19–20). Forty-seven species of benthic foraminifera were identified and quantitatively analyzed to determine changes in paleo-water depth. Three local benthic biofacies, the Elphidium biofacies, the Cibicides biofacies and the Uvigerina biofacies, were recognized, and six microfacies types were distinguished. These analyses indicate that the studied succession was deposited under shallow marine environmental conditions representing a single 3rd-order depositional sequence. The interpreted sea-level curve can be correlated with the global curves during the late Eocene, and the correlation suggests a sea-level rise during E14 Zone, followed by a sea-level fall in E15 zone.

Perimeter leakage current in polymer light emitting diodes

Germà Garcia-Belmonte,José M. Montero,Yassid Ayyad-Limonge,Eva M. Barea,Juan Bisquert,Henk J. Bolink 한국물리학회 2009 Current Applied Physics Vol.9 No.3

Observation of leakage current paths through the device perimeter in standard poly(phenylene vinylene)-based light-emitting devices is reported. Perimeter leakage currents govern the diode performance in reverse and low positive bias and exhibit an ohmic character. Current density correlates with the perimeter-to-area ratio thus indicating that leakage currents are mainly confined on polymer regions in the vicinity of metallic contact limits (device perimeter). Observation of leakage current paths through the device perimeter in standard poly(phenylene vinylene)-based light-emitting devices is reported. Perimeter leakage currents govern the diode performance in reverse and low positive bias and exhibit an ohmic character. Current density correlates with the perimeter-to-area ratio thus indicating that leakage currents are mainly confined on polymer regions in the vicinity of metallic contact limits (device perimeter).

Dental Caries Experience and Oral Health Practice among 12-Years-Old Schoolchildren

Eman K. M. Mansur,Halima A. Ayyad,Raga A. Elzahaf 대한예방치과학회 2022 International Journal of Clinical Preventive Denti Vol.18 No.1

Objectives: To assess the experience of dental caries and practice of oral health preventive measures. Methods: This was a secondary data study extracted from primary data through a cross-sectional study of a random sample of two hundred and forty-six 12 years-old Libyan schoolchildren (in 2019). Children underwent clinical examinations for dental caries experience. Then, they asked to complete a self-administrated questionnaire that designed to evaluate the oral health practices. The collected data were analysed using SPSS for Windows, version 25. The alpha value was 0.05. Results: The prevalence of dental caries, for the total sample, was 80.5% and the mean Decayed, Missing and Filled Teeth index (DMFT) was 2.4 (SD, 1.7). A clear gradient in the DMFT means with statistically significant was observed only across the categories of frequency of toothbrushing and frequency of sugary foods and drinks consumption in between meals. In addition, statistical significant was found for using fluoridated toothpaste. Conclusion: Dental caries in children aged 12 years old was prevalent in this study. The present survey provided an overview of practice of oral health preventive measures of participants, as the differences in these practices have influenced the DMFT values and provided knowledge about the disease experience.

Maximizing Strength of CKD – Stabilized Expansive Clayey Soil Using Natural Zeolite

Abdulla A. Sharo,Fathi M. Shaqour,Jomana M. Ayyad 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.4

The influence of pozzolanic materials on calcium-based soil stabilization technique has recently attracted researchers’ attention as such materials may catalyze the occurrence of pozzolanic reactions due to their high SiO2 and AL2O3 content. In this study, the effect of adding natural zeolite, which is a common pozzolanic material, on soil stabilized with cement kiln dust (CKD) is investigated. The optimal CKD content was determined by conducting tests on soil treated with percentages of CKD (0%, 2%, 4%, 6%, 8%, 10%, and 12%), and then, the optimal CKD treatment was applied on soil replaced by different zeolite percentages (1%, 3%, 5%, 10%, and 15%). Atterberg limits, swelling, California bearing ratio and unconfined compression tests were performed on all samples to evaluate the performance of additives in stabilization. Unconfined compression test samples were cured for 0, 7, 14 and 28 days to study the effect of time. Addition of CKD resulted in reduction of soil swelling and a significant increase in the long-term strength to an optimum of 10% that resulted in 3-folds of strength value higher than the based soil. Addition of 15% natural zeolite to the optimized CKD stabilized soil, caused 21% increase of strength higher than that with CKD optimized soil, however the swelling is only slightly reduced.

Synthesis and Antiproliferative Potency within Anticonvulsant of Novel Bichalcone Derivatives

Mansour, Eman,El-Badry, Yaser A.,El-Tokhy, Afaf,Ayyad, Rezed,Abd-Rabou, Ahmed A. Korean Chemical Society 2020 대한화학회지 Vol.64 No.1

An efficient and facile procedure has been developed for the synthesis of novel bichalcone derivatives (4a, 4b). The key step contains the solvent-free aldol synthesis of bichalcones based on quinones. Bichalcones (4a, 4b) were used as precursors for the synthesis of some interesting heterocyclic compounds like, diazepines (5a, 5b), pyrazolo-pyrimidines (7a, 7b), and pyrazoline derivatives (8a, 8b). Moreover, new thioxopyrimidine derivatives (9a, 9b) were furnished and used as a functionalizing agent to produce the triazole-pyrimidines (11, 12) and the carbonitrile derivative (14). All the synthesized compounds were fully characterized using physical and spectral data like, FT-IR, ¹H NMR, ¹³C NMR, and MS. Bichalcones (4a, 4b) and diazepines (5a, 5b) were screened for their anticonvulsant activity, where compounds (4a, 5a, and 5b) revealed potent anticonvulsant activity compared to diazepam. On the other hand, some of the prepared compounds were screened for their antiproliferative activity and they showed significant cytotoxic effects on most of the cancer cell lines with regard to broad spectrum antitumor activity.