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Thermal stability, glass transition and crystallization kinetics of Se95−xSb5Inx chalcogenide

Research Abstract

Calorimetric measurements of chalcogenide Se95−xSb5Inx (x = 0, 6, 8 and 10 at%) alloys are carried out using differential thermal analysis (DTA). The glass forming ability and glass transition are analyzed based on the heating rate dependence. The ability to form crystals is found to be increased with increasing In content indicating the suitably for the anticipated storage. Both the glass transition temperature and the glass transition activation energy increase with increasing In content. The crystallization due to the addition of In to the Se–Sb system is investigated using X-ray diffraction (XRD) and scanning electron microscope (SEM). The crystallization process is described by two models. These are Johnson–Mehl–Avrami (JMA) model and the empirical Sestak–Berggren (SB) model using an iso-conversional method of the transformation rate. The activation energy of crystallization is found to be increased with increasing In content. Based on the evaluated values of Avrami exponent (n), the crystallization growth is not dimensionally the same for the compositions.
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Thermal stability, glass transition and crystallization kinetics of Se95−xSb5Inx... | Request PDF. Available from: https://www.researchgate.net/publication/322749528_Thermal_stability_gl… [accessed Feb 13 2018].

Research Authors
Sherouk Sh. El‑sonbaty1 · M. I. Abd‑Elrahman1· A. A. Abu‑Sehly1· M. M. Hafiz1
Research Department
Research Journal
Applied Physics A
Research Pages
pp. 186 - 199
Research Publisher
NULL
Research Rank
1
Research Vol
Vol. 124
Research Website
NULL
Research Year
2018

Thermal stability, glass transition and crystallization kinetics of Se95−xSb5Inx chalcogenide

Research Abstract

Calorimetric measurements of chalcogenide Se95−xSb5Inx (x = 0, 6, 8 and 10 at%) alloys are carried out using differential thermal analysis (DTA). The glass forming ability and glass transition are analyzed based on the heating rate dependence. The ability to form crystals is found to be increased with increasing In content indicating the suitably for the anticipated storage. Both the glass transition temperature and the glass transition activation energy increase with increasing In content. The crystallization due to the addition of In to the Se–Sb system is investigated using X-ray diffraction (XRD) and scanning electron microscope (SEM). The crystallization process is described by two models. These are Johnson–Mehl–Avrami (JMA) model and the empirical Sestak–Berggren (SB) model using an iso-conversional method of the transformation rate. The activation energy of crystallization is found to be increased with increasing In content. Based on the evaluated values of Avrami exponent (n), the crystallization growth is not dimensionally the same for the compositions.
Do you want to read the rest of this article?

Thermal stability, glass transition and crystallization kinetics of Se95−xSb5Inx... | Request PDF. Available from: https://www.researchgate.net/publication/322749528_Thermal_stability_gl… [accessed Feb 13 2018].

Research Authors
Sherouk Sh. El‑sonbaty1 · M. I. Abd‑Elrahman1· A. A. Abu‑Sehly1· M. M. Hafiz1
Research Department
Research Journal
Applied Physics A
Research Pages
pp. 186 - 199
Research Publisher
NULL
Research Rank
1
Research Vol
Vol. 124
Research Website
NULL
Research Year
2018

Thermal stability, glass transition and crystallization kinetics of Se95−xSb5Inx chalcogenide

Research Abstract

Calorimetric measurements of chalcogenide Se95−xSb5Inx (x = 0, 6, 8 and 10 at%) alloys are carried out using differential thermal analysis (DTA). The glass forming ability and glass transition are analyzed based on the heating rate dependence. The ability to form crystals is found to be increased with increasing In content indicating the suitably for the anticipated storage. Both the glass transition temperature and the glass transition activation energy increase with increasing In content. The crystallization due to the addition of In to the Se–Sb system is investigated using X-ray diffraction (XRD) and scanning electron microscope (SEM). The crystallization process is described by two models. These are Johnson–Mehl–Avrami (JMA) model and the empirical Sestak–Berggren (SB) model using an iso-conversional method of the transformation rate. The activation energy of crystallization is found to be increased with increasing In content. Based on the evaluated values of Avrami exponent (n), the crystallization growth is not dimensionally the same for the compositions.
Do you want to read the rest of this article?

Thermal stability, glass transition and crystallization kinetics of Se95−xSb5Inx... | Request PDF. Available from: https://www.researchgate.net/publication/322749528_Thermal_stability_gl… [accessed Feb 13 2018].

Research Authors
Sherouk Sh. El‑sonbaty1 · M. I. Abd‑Elrahman1· A. A. Abu‑Sehly1· M. M. Hafiz1
Research Department
Research Journal
Applied Physics A
Research Pages
pp. 186 - 199
Research Publisher
NULL
Research Rank
1
Research Vol
Vol. 124
Research Website
NULL
Research Year
2018

Thickness and optical constants calculation for chalcogenide-alkali metal Se 80 Te 8 (NaCl) 12 thin film

Research Abstract

Chalcogenide-alkali metal semiconducting thin films of four different thicknesses of Se80Te8(NaCl)12 are deposited from bulk by thermal evaporation technique. The crystallinity of the film improves with increasing of thickness as indicated by the recorded X-ray diffraction patterns. The transmission and reflection spectra are measured in the wavelength range of the incident photons from 250 to 2500 nm. The thickness and optical constants of the films are calculated based on Swanepeol method using the interference patterns appeared in the transmission spectra. It is found that the films have absorption mechanism which is an indirect allowed transition. The effect of the film thickness on the refractive index and the high-frequency dielectric constant are studied. With increasing the film thickness, both the absorption coefficient and high-frequency dielectric constant increase while the single-oscillator energy, optical band gap and extinction coefficient decrease.

Thickness and optical constants calculation for chalcogenide-alkali metal Se 80... | Request PDF. Available from: https://www.researchgate.net/publication/316817569_Thickness_and_optica… [accessed Feb 13 2018].

Research Authors
M.I. Abd-Elrahman ⁎, A.A. Abu-Sehly, Y.M. Bakier, M.M. Hafiz
Research Department
Research Journal
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
Research Pages
pp. 243 - 248
Research Publisher
NULL
Research Rank
1
Research Vol
Vol. 184
Research Website
NULL
Research Year
2017

Thickness and optical constants calculation for chalcogenide-alkali metal Se 80 Te 8 (NaCl) 12 thin film

Research Abstract

Chalcogenide-alkali metal semiconducting thin films of four different thicknesses of Se80Te8(NaCl)12 are deposited from bulk by thermal evaporation technique. The crystallinity of the film improves with increasing of thickness as indicated by the recorded X-ray diffraction patterns. The transmission and reflection spectra are measured in the wavelength range of the incident photons from 250 to 2500 nm. The thickness and optical constants of the films are calculated based on Swanepeol method using the interference patterns appeared in the transmission spectra. It is found that the films have absorption mechanism which is an indirect allowed transition. The effect of the film thickness on the refractive index and the high-frequency dielectric constant are studied. With increasing the film thickness, both the absorption coefficient and high-frequency dielectric constant increase while the single-oscillator energy, optical band gap and extinction coefficient decrease.

Thickness and optical constants calculation for chalcogenide-alkali metal Se 80... | Request PDF. Available from: https://www.researchgate.net/publication/316817569_Thickness_and_optica… [accessed Feb 13 2018].

Research Authors
M.I. Abd-Elrahman ⁎, A.A. Abu-Sehly, Y.M. Bakier, M.M. Hafiz
Research Department
Research Journal
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
Research Pages
pp. 243 - 248
Research Publisher
NULL
Research Rank
1
Research Vol
Vol. 184
Research Website
NULL
Research Year
2017

Thickness and optical constants calculation for chalcogenide-alkali metal Se 80 Te 8 (NaCl) 12 thin film

Research Abstract

Chalcogenide-alkali metal semiconducting thin films of four different thicknesses of Se80Te8(NaCl)12 are deposited from bulk by thermal evaporation technique. The crystallinity of the film improves with increasing of thickness as indicated by the recorded X-ray diffraction patterns. The transmission and reflection spectra are measured in the wavelength range of the incident photons from 250 to 2500 nm. The thickness and optical constants of the films are calculated based on Swanepeol method using the interference patterns appeared in the transmission spectra. It is found that the films have absorption mechanism which is an indirect allowed transition. The effect of the film thickness on the refractive index and the high-frequency dielectric constant are studied. With increasing the film thickness, both the absorption coefficient and high-frequency dielectric constant increase while the single-oscillator energy, optical band gap and extinction coefficient decrease.

Thickness and optical constants calculation for chalcogenide-alkali metal Se 80... | Request PDF. Available from: https://www.researchgate.net/publication/316817569_Thickness_and_optica… [accessed Feb 13 2018].

Research Authors
M.I. Abd-Elrahman ⁎, A.A. Abu-Sehly, Y.M. Bakier, M.M. Hafiz
Research Department
Research Journal
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
Research Pages
pp. 243 - 248
Research Publisher
NULL
Research Rank
1
Research Vol
Vol. 184
Research Website
NULL
Research Year
2017

Thickness and optical constants calculation for chalcogenide-alkali metal Se 80 Te 8 (NaCl) 12 thin film

Research Abstract

Chalcogenide-alkali metal semiconducting thin films of four different thicknesses of Se80Te8(NaCl)12 are deposited from bulk by thermal evaporation technique. The crystallinity of the film improves with increasing of thickness as indicated by the recorded X-ray diffraction patterns. The transmission and reflection spectra are measured in the wavelength range of the incident photons from 250 to 2500 nm. The thickness and optical constants of the films are calculated based on Swanepeol method using the interference patterns appeared in the transmission spectra. It is found that the films have absorption mechanism which is an indirect allowed transition. The effect of the film thickness on the refractive index and the high-frequency dielectric constant are studied. With increasing the film thickness, both the absorption coefficient and high-frequency dielectric constant increase while the single-oscillator energy, optical band gap and extinction coefficient decrease.

Thickness and optical constants calculation for chalcogenide-alkali metal Se 80... | Request PDF. Available from: https://www.researchgate.net/publication/316817569_Thickness_and_optica… [accessed Feb 13 2018].

Research Authors
M.I. Abd-Elrahman ⁎, A.A. Abu-Sehly, Y.M. Bakier, M.M. Hafiz
Research Department
Research Journal
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
Research Pages
pp. 243 - 248
Research Publisher
NULL
Research Rank
1
Research Vol
Vol. 184
Research Website
NULL
Research Year
2017

Enhancement of exopolysaccharide production by Stenotrophomonas maltophilia and Brevibacillus parabrevis isolated from root nodules of Cicer arietinum L. and Vigna unguiculata L. (Walp.) plants

Research Abstract

This study intended to determine the ability of endophytic bacteria recovered from root nodules of Cicer arietinum L. and
Vigna unguiculata L. (Walp.) plants to synthesize exopolysaccharide (EPS) and to enhance the production by changing
nutritional factors. Twenty endophytic bacteria isolated from root nodules of Cicer arietinum and Vigna unguiculata were
tested for their production of EPS. High EPS-producing isolates were identified on phenotypic and genotypic characteristics.
Among 20 isolates, Stenotrophomonas maltophilia (C6) and Brevibacillus parabrevis (V4) isolated from root nodules of
Cicer arietinum and Vigna unguiculata produced a high EPS yield in comparison with other isolates. Using 1% of sucrose
as sole carbon source increases the concentration of EPS produced by S. maltophilia and B. parabrevis (65 and 107%,
respectively). EPS produced by S. maltophilia and B. parabrevis was increased by the addition of fructose and lactose
(0.1%). Addition of 1.68 g/L KNO3
or 2.49 g/L glycine to modified yeast extract mannitol medium (YEMB) significantly
increased EPS production by S. maltophilia and B. parabrevis. Furthermore, the presence of Fe3O4
nanoparticles (25–50 μg/
mL) in the modified YEMB medium increased EPS yield by B. parabrevis. Chemical characterization of EPS by GC–MS
and FTIR indicate that the EPS biochemical composition is dependent on the bioavailability of carbon substrates and is
controlled by limiting nutrients. The combination of the best two carbon sources sucrose (0.9%) and fructose or lactose
(0.1%) in the presence of KNO3
or glycine as the best nitrogen sources significantly increased EPS yield of S. maltophilia
and B. parabrevis, respectively.

Research Authors
Mohamed Hemida Abd‑Alla1 · Shymaa R. Bashandy1 · Nivien A. Nafady1 · Amany A. Hassan2
Research Journal
Rendiconti Lincei. Scienze Fisiche e Naturali
Research Pages
NULL
Research Publisher
ٍٍSpringer
Research Rank
1
Research Vol
NULL
Research Website
http://rdcu.be/GCvt
Research Year
2018

Enhancement of exopolysaccharide production by Stenotrophomonas maltophilia and Brevibacillus parabrevis isolated from root nodules of Cicer arietinum L. and Vigna unguiculata L. (Walp.) plants

Research Abstract

This study intended to determine the ability of endophytic bacteria recovered from root nodules of Cicer arietinum L. and
Vigna unguiculata L. (Walp.) plants to synthesize exopolysaccharide (EPS) and to enhance the production by changing
nutritional factors. Twenty endophytic bacteria isolated from root nodules of Cicer arietinum and Vigna unguiculata were
tested for their production of EPS. High EPS-producing isolates were identified on phenotypic and genotypic characteristics.
Among 20 isolates, Stenotrophomonas maltophilia (C6) and Brevibacillus parabrevis (V4) isolated from root nodules of
Cicer arietinum and Vigna unguiculata produced a high EPS yield in comparison with other isolates. Using 1% of sucrose
as sole carbon source increases the concentration of EPS produced by S. maltophilia and B. parabrevis (65 and 107%,
respectively). EPS produced by S. maltophilia and B. parabrevis was increased by the addition of fructose and lactose
(0.1%). Addition of 1.68 g/L KNO3
or 2.49 g/L glycine to modified yeast extract mannitol medium (YEMB) significantly
increased EPS production by S. maltophilia and B. parabrevis. Furthermore, the presence of Fe3O4
nanoparticles (25–50 μg/
mL) in the modified YEMB medium increased EPS yield by B. parabrevis. Chemical characterization of EPS by GC–MS
and FTIR indicate that the EPS biochemical composition is dependent on the bioavailability of carbon substrates and is
controlled by limiting nutrients. The combination of the best two carbon sources sucrose (0.9%) and fructose or lactose
(0.1%) in the presence of KNO3
or glycine as the best nitrogen sources significantly increased EPS yield of S. maltophilia
and B. parabrevis, respectively.

Research Authors
Mohamed Hemida Abd‑Alla1 · Shymaa R. Bashandy1 · Nivien A. Nafady1 · Amany A. Hassan2
Research Journal
Rendiconti Lincei. Scienze Fisiche e Naturali
Research Member
Research Pages
NULL
Research Publisher
ٍٍSpringer
Research Rank
1
Research Vol
NULL
Research Website
http://rdcu.be/GCvt
Research Year
2018

Enhancement of exopolysaccharide production by Stenotrophomonas maltophilia and Brevibacillus parabrevis isolated from root nodules of Cicer arietinum L. and Vigna unguiculata L. (Walp.) plants

Research Abstract

This study intended to determine the ability of endophytic bacteria recovered from root nodules of Cicer arietinum L. and
Vigna unguiculata L. (Walp.) plants to synthesize exopolysaccharide (EPS) and to enhance the production by changing
nutritional factors. Twenty endophytic bacteria isolated from root nodules of Cicer arietinum and Vigna unguiculata were
tested for their production of EPS. High EPS-producing isolates were identified on phenotypic and genotypic characteristics.
Among 20 isolates, Stenotrophomonas maltophilia (C6) and Brevibacillus parabrevis (V4) isolated from root nodules of
Cicer arietinum and Vigna unguiculata produced a high EPS yield in comparison with other isolates. Using 1% of sucrose
as sole carbon source increases the concentration of EPS produced by S. maltophilia and B. parabrevis (65 and 107%,
respectively). EPS produced by S. maltophilia and B. parabrevis was increased by the addition of fructose and lactose
(0.1%). Addition of 1.68 g/L KNO3
or 2.49 g/L glycine to modified yeast extract mannitol medium (YEMB) significantly
increased EPS production by S. maltophilia and B. parabrevis. Furthermore, the presence of Fe3O4
nanoparticles (25–50 μg/
mL) in the modified YEMB medium increased EPS yield by B. parabrevis. Chemical characterization of EPS by GC–MS
and FTIR indicate that the EPS biochemical composition is dependent on the bioavailability of carbon substrates and is
controlled by limiting nutrients. The combination of the best two carbon sources sucrose (0.9%) and fructose or lactose
(0.1%) in the presence of KNO3
or glycine as the best nitrogen sources significantly increased EPS yield of S. maltophilia
and B. parabrevis, respectively.

Research Authors
Mohamed Hemida Abd‑Alla1 · Shymaa R. Bashandy1 · Nivien A. Nafady1 · Amany A. Hassan2
Research Journal
Rendiconti Lincei. Scienze Fisiche e Naturali
Research Member
Research Pages
NULL
Research Publisher
ٍٍSpringer
Research Rank
1
Research Vol
NULL
Research Website
http://rdcu.be/GCvt
Research Year
2018
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