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Papers by m. rashad

Research paper thumbnail of Experimental investigations on elastic and radiation shielding parameters of WO3-B2O3-TeO2 glasses

Journal of Non-Crystalline Solids, 2020

Seven different tungsten boro-tellurite glass samples coded as TBW00, TBW05, TBW10, TBW15, TBW20,... more Seven different tungsten boro-tellurite glass samples coded as TBW00, TBW05, TBW10, TBW15, TBW20, TBW25, and TBW30 have been fabricated using the melt-quenching method. Experimental mechanical properties were calculated with the help of ultrasonic velocities [shear (V S) and longitudinal (V L)] and density (ρ). The synergistic positive effect of WO 3 additive on protective glasses with high efficiency against gamma is underlined. The mass attenuation coefficients (MAC) at the energy range of 0.015 to 15 MeV have been calculated by XCOM theoretical program. Both the shielding and mechanical results show that the glass materials have good protection against gamma radiation. According to the results obtained, the TBW30 glass sample with the highest WO 3 additive showed great nuclear radiation protection and elastic properties among other samples.

Research paper thumbnail of Control optical characterizations of Ta+5–doped B2O3–Si2O–CaO–BaO glasses by irradiation dose

Optical Materials, 2021

Abstract Borosilicate glasses within 25B2O3–15Si2O–10CaO-(50-x)BaO-xTa2O5 system at different Ta2... more Abstract Borosilicate glasses within 25B2O3–15Si2O–10CaO-(50-x)BaO-xTa2O5 system at different Ta2O5 contents (x = 0, 4, 8, 12, and 15 wt%) were synthesized via quenching technique. The effect of irradiation doses of both 10, and 40 kGy, as well as the Ta2O5 ratio on the structural and optical characteristics of the prepared glasses were studied. The investigations were carried out using UV–Vis–NIR spectrophotometer, differential scanning calorimetry (DSC), X-ray powder diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR) techniques. Physical parameters such as density, molar volumes, refractive index, optical bandgap, Urbach energy, optical density, extinction coefficient, optical sheet resistance, and thermal emissivity of 25B2O3–15Si2O–10CaO-(50-x)BaO-xTa2O5 samples with different irradiation doses were investigated. The results show that irradiation does not affect the crystal structure for the present samples even at 40 kGy. The optical aspects reveal the indirect allowed optical transition for the studied samples. The evaluated optical parameters show an effective influence towards both Ta2O5 content and irradiation does which forces the optical applications.

Research paper thumbnail of The effect of composition and γ-irradiation on the Vickers hardness, structural and optical properties of xLiNbO3-25CaO-35PbO-(40-x) waste systems

Ceramics International, 2021

Research paper thumbnail of Synthesis, optical, structural and physical properties of newly developed dolomite reinforced borate glasses for nuclear radiation shielding utilizations: An experimental and simulation study

Optical Materials, 2021

Abstract This work aimed to investigate optical, structural and physical properties of newly deve... more Abstract This work aimed to investigate optical, structural and physical properties of newly developed Dolomite reinforced borate glasses via experimental and simulation techniques. Accordingly, a glass composition (40-x) B2O3–40PbO–20ZnO-xDolomite of various compositions of Dolomite [CaMg(CO3)2] where, (x = 0.0, 1.0, 2.0, 3.0 and 4 wt%) were synthesized by using melt-quenching method. The Dolomite [CaMg(CO3)2] doped glasses encoded DG-0, DG-1, DG-2, DG-3 and DG4 with different compositions are prepared. The optical properties of prepared dolomite glasses have been measured. The results show an enhancement of the absorbance as dolomite contents increases. Using gamma spectroscopy, the radiation shielding properties have been measured. Moreover. Comparatively higher density (DG-4 = 3.868 g/cm3), greater μ, μm and lower T1/2, λ values achieved for (40-x) B2O3–40PbO–20ZnO-xDolomite glass indicated it as a better gamma shield. Besides, the calculated Radiation protection efficiency at 1 cm observe that the (40-x) B2O3–40PbO–20ZnO-x[CaMg(CO3)2] sample has commensurately greater and ranged (14.11565 at 2.614 MeV and 98.35382 at 0.081 MeV). The results observed that Dolomite addition improves the gamma protection ability of lead-zinc borate glasses. The results indicate that the highest Dolomite addition encoded DG-4 has the best shielding competence with measurable physical and optical properties.

Research paper thumbnail of Optical, structural and gamma ray shielding properties of dolomite doped lithium borate glasses for radiation shielding applications

Journal of Non-Crystalline Solids, 2020

The elemental analysis of dolomite [CaMg(CO 3)] doped glasses encoded DG10, DG20, DG30 and DG40 w... more The elemental analysis of dolomite [CaMg(CO 3)] doped glasses encoded DG10, DG20, DG30 and DG40 with different compositions is tested using Energy Dispersive X-ray (EDX) technique. Next, the surface morphology of fabricated glasses was investigated with scanning electron microscopy (SEM). On the other hand, the optical properties of fabricated the Dolomite additive were evaluated along the wavelength ranged from 300 to 900 nm. At last, nuclear radiation shielding properties of dolomite glasses were determined for gamma-rays. It is observed from the optical absorption spectra that the surface becomes smooth with no agglomerations with Dolomite%30 and %40. In addition, the results showed that Dolomite additive improves the gamma protecting capacity of lithium borate glasses. As a result, it can be referred that a glass sample with the highest Dolomite additive encoded DG40 has better shielding efficiency in terms of radiation shielding.

Research paper thumbnail of An assessment of cross-infection control procedures among English-speaking Caribbean general dental practitioners. A regional preliminary study

International Dental Journal, 1998

A survey was undertaken to assess the level of compliance with recommended infection control proc... more A survey was undertaken to assess the level of compliance with recommended infection control procedures among English-speaking Caribbean general dental practitioners. A four page questionnaire was sent to all practitioners in 18 English-speaking Caribbean islands. A response rate of 32 per cent was obtained. A large proportion of dentists followed the recommended barrier techniques particularly the use of gloves and facemasks. The most commonly available methods of sterilisation were steam autoclaves (82 per cent) and cold solutions (94 per cent). Seventy four per cent of respondents had received hepatitis B vaccination. A high percentage of dentists showed willingness to treat HBV (95 per cent) and HIV (84 per cent) carriers and this level of willingness to treat infectious patients has rarely been reported previously. There is an urgent need for further improvements to avoid getting inoculation injuries and splatters in the face or eyes with body fluids. Disposal of sharps and collection of solid waste are to be upgraded. The Caribbean Atlantic Regional Dental Association is planning to carry out similar research before the end of the year 2000.

Research paper thumbnail of Experimental investigations on elastic and radiation shielding parameters of WO3-B2O3-TeO2 glasses

Journal of Non-Crystalline Solids, 2020

Seven different tungsten boro-tellurite glass samples coded as TBW00, TBW05, TBW10, TBW15, TBW20,... more Seven different tungsten boro-tellurite glass samples coded as TBW00, TBW05, TBW10, TBW15, TBW20, TBW25, and TBW30 have been fabricated using the melt-quenching method. Experimental mechanical properties were calculated with the help of ultrasonic velocities [shear (V S) and longitudinal (V L)] and density (ρ). The synergistic positive effect of WO 3 additive on protective glasses with high efficiency against gamma is underlined. The mass attenuation coefficients (MAC) at the energy range of 0.015 to 15 MeV have been calculated by XCOM theoretical program. Both the shielding and mechanical results show that the glass materials have good protection against gamma radiation. According to the results obtained, the TBW30 glass sample with the highest WO 3 additive showed great nuclear radiation protection and elastic properties among other samples.

Research paper thumbnail of Control optical characterizations of Ta+5–doped B2O3–Si2O–CaO–BaO glasses by irradiation dose

Optical Materials, 2021

Abstract Borosilicate glasses within 25B2O3–15Si2O–10CaO-(50-x)BaO-xTa2O5 system at different Ta2... more Abstract Borosilicate glasses within 25B2O3–15Si2O–10CaO-(50-x)BaO-xTa2O5 system at different Ta2O5 contents (x = 0, 4, 8, 12, and 15 wt%) were synthesized via quenching technique. The effect of irradiation doses of both 10, and 40 kGy, as well as the Ta2O5 ratio on the structural and optical characteristics of the prepared glasses were studied. The investigations were carried out using UV–Vis–NIR spectrophotometer, differential scanning calorimetry (DSC), X-ray powder diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR) techniques. Physical parameters such as density, molar volumes, refractive index, optical bandgap, Urbach energy, optical density, extinction coefficient, optical sheet resistance, and thermal emissivity of 25B2O3–15Si2O–10CaO-(50-x)BaO-xTa2O5 samples with different irradiation doses were investigated. The results show that irradiation does not affect the crystal structure for the present samples even at 40 kGy. The optical aspects reveal the indirect allowed optical transition for the studied samples. The evaluated optical parameters show an effective influence towards both Ta2O5 content and irradiation does which forces the optical applications.

Research paper thumbnail of The effect of composition and γ-irradiation on the Vickers hardness, structural and optical properties of xLiNbO3-25CaO-35PbO-(40-x) waste systems

Ceramics International, 2021

Research paper thumbnail of Synthesis, optical, structural and physical properties of newly developed dolomite reinforced borate glasses for nuclear radiation shielding utilizations: An experimental and simulation study

Optical Materials, 2021

Abstract This work aimed to investigate optical, structural and physical properties of newly deve... more Abstract This work aimed to investigate optical, structural and physical properties of newly developed Dolomite reinforced borate glasses via experimental and simulation techniques. Accordingly, a glass composition (40-x) B2O3–40PbO–20ZnO-xDolomite of various compositions of Dolomite [CaMg(CO3)2] where, (x = 0.0, 1.0, 2.0, 3.0 and 4 wt%) were synthesized by using melt-quenching method. The Dolomite [CaMg(CO3)2] doped glasses encoded DG-0, DG-1, DG-2, DG-3 and DG4 with different compositions are prepared. The optical properties of prepared dolomite glasses have been measured. The results show an enhancement of the absorbance as dolomite contents increases. Using gamma spectroscopy, the radiation shielding properties have been measured. Moreover. Comparatively higher density (DG-4 = 3.868 g/cm3), greater μ, μm and lower T1/2, λ values achieved for (40-x) B2O3–40PbO–20ZnO-xDolomite glass indicated it as a better gamma shield. Besides, the calculated Radiation protection efficiency at 1 cm observe that the (40-x) B2O3–40PbO–20ZnO-x[CaMg(CO3)2] sample has commensurately greater and ranged (14.11565 at 2.614 MeV and 98.35382 at 0.081 MeV). The results observed that Dolomite addition improves the gamma protection ability of lead-zinc borate glasses. The results indicate that the highest Dolomite addition encoded DG-4 has the best shielding competence with measurable physical and optical properties.

Research paper thumbnail of Optical, structural and gamma ray shielding properties of dolomite doped lithium borate glasses for radiation shielding applications

Journal of Non-Crystalline Solids, 2020

The elemental analysis of dolomite [CaMg(CO 3)] doped glasses encoded DG10, DG20, DG30 and DG40 w... more The elemental analysis of dolomite [CaMg(CO 3)] doped glasses encoded DG10, DG20, DG30 and DG40 with different compositions is tested using Energy Dispersive X-ray (EDX) technique. Next, the surface morphology of fabricated glasses was investigated with scanning electron microscopy (SEM). On the other hand, the optical properties of fabricated the Dolomite additive were evaluated along the wavelength ranged from 300 to 900 nm. At last, nuclear radiation shielding properties of dolomite glasses were determined for gamma-rays. It is observed from the optical absorption spectra that the surface becomes smooth with no agglomerations with Dolomite%30 and %40. In addition, the results showed that Dolomite additive improves the gamma protecting capacity of lithium borate glasses. As a result, it can be referred that a glass sample with the highest Dolomite additive encoded DG40 has better shielding efficiency in terms of radiation shielding.

Research paper thumbnail of An assessment of cross-infection control procedures among English-speaking Caribbean general dental practitioners. A regional preliminary study

International Dental Journal, 1998

A survey was undertaken to assess the level of compliance with recommended infection control proc... more A survey was undertaken to assess the level of compliance with recommended infection control procedures among English-speaking Caribbean general dental practitioners. A four page questionnaire was sent to all practitioners in 18 English-speaking Caribbean islands. A response rate of 32 per cent was obtained. A large proportion of dentists followed the recommended barrier techniques particularly the use of gloves and facemasks. The most commonly available methods of sterilisation were steam autoclaves (82 per cent) and cold solutions (94 per cent). Seventy four per cent of respondents had received hepatitis B vaccination. A high percentage of dentists showed willingness to treat HBV (95 per cent) and HIV (84 per cent) carriers and this level of willingness to treat infectious patients has rarely been reported previously. There is an urgent need for further improvements to avoid getting inoculation injuries and splatters in the face or eyes with body fluids. Disposal of sharps and collection of solid waste are to be upgraded. The Caribbean Atlantic Regional Dental Association is planning to carry out similar research before the end of the year 2000.