https://repository.sustech.edu/handle/123456789/1303 2026-04-04T12:20:01Z 2026-04-04T12:20:01Z Ahmed,Wafa Omer Supervisor, - Ahmed Hassan S. Elkheir https://repository.sustech.edu/handle/123456789/2382 2016-01-28T06:48:06Z 2008-08-01T00:00:00Z

Photobleaching of anthocyanins using tunable dye laser Ahmed,Wafa Omer; Supervisor, - Ahmed Hassan S. Elkheir The flowers of Hibiscus sabdarifa were extracted with acidified methanol. The Anthocyanin of Hibiscus sabdarifa was obtained as red needles from absolute ethanol. A dye laser operating at 520 nm was used to bleach the red- colored anthocyanin. A mixture of the anthocyanin and triethylamine was irradiated with laser for 40 minutes. Under such conditions the iv ‫‪The anthocyanin then oxidizes triethylamine and reduces to a colourless‬‬ ‫.‪radical‬‬ ‫‪AS‬‬ ‫1‬ ‫*‪AS‬‬ ‫3‬ ‫‪hν‬‬ ‫0‪AS‬‬ ‫1*‬ ‫)‪(Red‬‬ ‫3*‪AS• + •NR‬‬ ‫3‬ ‫3‪AS* +:NR‬‬ ‫)‪(Colourless‬‬ ‫‬ Thesis

2008-08-01T00:00:00Z Mohamed, Setana Abd alhi Supervisor, -Ali Abdel Rahman Saeed Marouf https://repository.sustech.edu/handle/123456789/21245 2018-08-05T08:16:50Z 2017-12-03T00:00:00Z

Comparison of the Effect of Different Lasers Wavelengths and Powers on Teeth Bleaching Mohamed, Setana Abd alhi; Supervisor, -Ali Abdel Rahman Saeed Marouf Lasers have been long introduced in dentistry. Today lasers are been used for Endodontic, Periodontal, Oral Surgery as well as restorative procedures. Here, the effect of different wavelengths on teeth bleaching and in pulp temperature was investigated. Teeth were exposure to diode lasers with 532 nm, 820 nm, 915 nm and continue Nd: YAG 1064nm laser in different exposure times specifically (30, 40, 50, and 60) second, the degree of staining after bleaching was evaluated, and the effects of laser bleaching in pulp temperature with and without gel during exposure to laser beam was determined. The results led to the conclusion that the temperature rises with increasing wavelength, power, and exposure time, whereas using gel shows lower rise in temperature. Finally, this study stated some recommendations, one of the most important recommendations don’t use high power in the bleaching process because the tooth will damage. Thesis

2017-12-03T00:00:00Z Mohammed, Ebdaa Salahudeen Supervisor, -Nafie A. Almuslet https://repository.sustech.edu/handle/123456789/20753 2018-04-22T06:50:30Z 2018-02-09T00:00:00Z

Quality Assessment of Medical Heparin Using Laser Scattering Technique Mohammed, Ebdaa Salahudeen; Supervisor, -Nafie A. Almuslet In this work, the goodness of the medical Heparin (concentration) was checked using the principle of laser scattering. A simple setup consists of diode laser with wavelength 532 nm and output power of 100 mW and USB spectrometerwere used to record the laser scattered intensity at angles of (〖45〗^°,〖90〗^° and 〖135〗^°). First of all, the relation between the concentration of the standard sample (NaCl) and the scattered laser intensity in these angles was pointed. Then the relation between the heparin concentration and the intensity of the scattered laser light was deduced for the three angles. The results showed that the relation between the angular scattered intensity and the sample concentration is a linear relation. This study proved that this setup was sensitive and efficient indiscovering any change in the sample concentration and any manipulation in theconcentrationof Heparin, so the goodness of Heparin can be checked. Thesis

2018-02-09T00:00:00Z Babikr, Faten Abdelrhim Mohammed Supervisor, -Nafie Abd Allattif Almuslet https://repository.sustech.edu/handle/123456789/20671 2018-04-12T05:40:41Z 2017-12-05T00:00:00Z

Determination of the optical properties of fabricated CuO disks using different lasers Babikr, Faten Abdelrhim Mohammed; Supervisor, -Nafie Abd Allattif Almuslet In this work, copper oxide (CuO) disks were prepared using a classical pressing machine, after mixing with potassium bromide. The disks were fabricated with different thicknesses (1.7, 2.59, 3.46, 4.29, 5.49, 5.92) mm. The optical properties of CuO disk were studied using different types of monochromatic light sources in the wavelength range (300-950) nm. The incident light intensities were measured in the absence of samples, which regarded as the reference ( ), then the transmitted intensity ( ) for each sample was measured by placing the monochromatic light source, the detector, and the sample on the same line. The reflected intensities ( ) also were measured by placing the monochromatic light source and the detector at angle of 450 with the samples. The absorption coefficient for each sample was calculated using Beer-Lambert law. In addition, the refractive index for each disk also was calculated. The optical properties (absorption coefficient, transmission percentage, and refractive index) of the fabricated disks, with different thicknesses, were plotted as a function of wavelengths of the light sources . The obtained results showed the possibility of using the CuO disks as an optical filters in certain wavelengths or as reflectors for other wavelengths Thesis

2017-12-05T00:00:00Z