Hossein Tavanai - Academia.edu (original) (raw)
Papers by Hossein Tavanai
Diamond and Related Materials, Dec 1, 2021
Polymers for Advanced Technologies, Nov 21, 2021
This study concerns the electrospinning of tragacanth nanofibers containing zinc oxide nanopartic... more This study concerns the electrospinning of tragacanth nanofibers containing zinc oxide nanoparticles with the aim of separating sulfur compounds from crude oil. Zinc oxide incorporated tragacanth nanofibers were electrospun from tragacanth solutions containing zinc oxide nanoparticles with concentrations of 5, 10, 15, and 20 (% w/w). The average diameter of these nanofibers were 91.6, 94.1, 95.4, and 97.8 nm, respectively. SEM images showed that zinc oxide nanoparticles incorporated tragacanth nanofibers were uniformly electrospun with no beads. FTIR analysis showed some interactions between zinc oxide nanoparticles and tragacanth macromolecules. XRD studies showed a two phase microstructure consisting of semi‐crystalline tragacanth matrix with zinc oxide crystallites dispersed in it. The highest filtration efficiency for 300 ml of Isfahan and Gachsaran crude oil was 75.3% and 62.2%, respectively. Moreover, the highest sulfur adsorption capacity obtained for Isfahan and Gachsaran crude oil was 211.20 mg g−1 and 108.19 mg g−1, respectively.
Journal of Inorganic and Organometallic Polymers and Materials, Jun 26, 2020
Journal of environmental chemical engineering, Jun 1, 2022
The Journal of The Textile Institute
International Journal of Biological Macromolecules, Oct 1, 2016
In this study, the fabrication of vanillin incorporated almond gum/polyvinyl alcohol (PVA) nanofi... more In this study, the fabrication of vanillin incorporated almond gum/polyvinyl alcohol (PVA) nanofibers through electrospinning has been investigated. Electrospinning of only almond gum was proved impossible. It was found that the aqueous solution of almond gum/PVA (80:20, concentration=7% (w/w)) containing 3% (w/w) vanillin could have successfully electrospun to uniform nanofibers with diameters as low as 77nm. According to the thermal analysis, incorporated vanillin in almond gum/PVA nanofibers showed higher thermal stability than free vanillin, making this composite especially suitable for high temperature applications. XRD and FTIR analyses proved the presence of vanillin in the almond gum/PVA nanofibers. It was also found that vanillin was dispersed as big crystallites in the matrix of almond gum/PVA nanofibers. FTIR analysis showed almond gum and PVA had chemical cross-linking by etheric bonds between COH groups of almond gum and OH groups of PVA. Also, in the nanofibers, there were no major interaction between vanillin and either almond gum or PVA.
Journal of Applied Polymer Science, 2021
Polymer Bulletin
This article reports the activation of dates stone powder precursor through hydrothermal and dryt... more This article reports the activation of dates stone powder precursor through hydrothermal and drythermal treatments leading to drastic morphological changes in dates stone powder. Depending on the type of activation, spherical or cavernous activated carbon is obtained. Hydrothermal activation brings about a mesoporous structure with average pore diameter of about 32 nm and walls being made of nicely shaped spheres with size in the range of 0.8–1.2 μm. On the other hand, drythermally activated samples show a cavernous structure with rectangular shape pores of around 2–5 μm and walls of about 1.3 μm thickness, being made of very closely packed small spheres. Hydrothermally and drythermally activated samples show a yield of 59.4% and 47.27%, respectively, which is considerably higher than the yield for traditionally activated dates stone. XRD analysis showed a considerably reduced crystallinity for the treated samples. FTIR results confirm the successfully conversion of dates stone into activated carbon. EDX results showed an increased share of carbon from 46.33 to 76.32% and 81.02% for hydrothermal and drythermal samples, respectively. Raman analysis showed a higher order for drythermally activated carbon than hydrothermal one.
Journal of Bioprocessing & Biotechniques, 2015
Copyright © 2014 Fatemeh Ajalloueian et al. This is an open access article distributed under the ... more Copyright © 2014 Fatemeh Ajalloueian et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Novel nanofibers from blends of polylactic-co-glycolic acid (PLGA) and chitosan have been produced through an emulsion electrospinning process. The spinning solution employed polyvinyl alcohol (PVA) as the emulsifier. PVA was extracted from the electrospun nanofibers, resulting in a final scaffold consisting of a blend of PLGA and chitosan.The fraction of chitosan in the final electrospunmat was adjusted from 0 to 33%. Analyses by scanning and transmission electronmicroscopy show uniform nanofibers with homogenous distribution of PLGA and chitosan in their cross section. Infrared spectroscopy verifies that electrospun mats contain both PLGA and chitosan. Moreover, contact angle measurements show that the electrospun PLGA/chitosa...
Journal of Sol-Gel Science and Technology, 2011
Abstract UV radiation causes serious damage to skin, and a protective system capable of absorbing... more Abstract UV radiation causes serious damage to skin, and a protective system capable of absorbing or reflecting UV radiation is required to protect skin. This paper describes the UV protection and photocatalytic properties of TiO2 nanofilm coated electrospun polyacrylonitrile (PAN) ...
ty, and birefringence has been studied by means of polarizing light microscope, DSC and FTIR. Ten... more ty, and birefringence has been studied by means of polarizing light microscope, DSC and FTIR. Tenacity and thermal shrinkage have also been studied. The results indicated that Yellow 83, Blue 15 and Black 7 act as monoclinic nucleating agents, whereas Violet19 and White 6 act as hexagonal nucleating agents. The nucleation effect of Red 48 seems to be negligible. Depending on the type of nucleation, the above mentioned parameters characterizing the microstructure of the fibres are affected. The birefringence of all coloured polypropylene fibres decreased as a result of pigment dyes added to the fibres. This leads to a reduction of the tenacity and thermal shrinkage of mass dyed BCF yarns.
A possibilistic linear regression, i.e. a linear regression with possibilistic coefficients, is e... more A possibilistic linear regression, i.e. a linear regression with possibilistic coefficients, is explained. The application of such possibilistic regression method for modeling of twist liveliness of false twist textured nylon yarns as a function of percentage retraction has been studied, based on a few available data. It turns out that possibilistic regression method is superior to conventional statistical regression, when a very small number of observations are available. In such cases the basic assumptions, under which statistical regression analysis is valid, can not be investigated. Based on some criterions, such as the total vagueness of models and the mean of predictive capabilities, the optimum fuzzy model has been derived.
This paper reports on the effect of fiber crimp frequency on sound absorption capability of stapl... more This paper reports on the effect of fiber crimp frequency on sound absorption capability of staple polypropylene nonwoven batts. Stuffer box was used to impart crimp to spun tow. Crimping of the tow renders the fibers the required textile applicability. In this work, polypropylene batts composed of staple fibers with linear densities of 9, 14, and 18 denier were employed. Three crimp frequency namely low, medium and high were imparted to fibers of each denier group. Impedance tube method with sound frequencies in the range of 250 – 4000 Hz was employed to measure the sound absorption coefficient of the batts. The results showed sound absorption properties of fibrous batts were affected by fiber crimp frequency, fiber fineness and web thickness. The highest sound absorption coefficient for the 9, 14 and 18 denier batts was 78.90, 77.14 and 71.18, respectively. The crimp frequency of the fibers making these batts was 1.9, 2.3 and 3.6 crimp per cm, respectively. It was found that highe...
The Journal of The Textile Institute, 2021
Polypropylene filament yarns, when compared with polyethyleneterephthalate and polyamide yarns ha... more Polypropylene filament yarns, when compared with polyethyleneterephthalate and polyamide yarns have lower stretchability after being false twist textured. To overcome this deficiency, other researchers have tried to lower the degree of crystallinity of this fibre by either tension annealing or blending it with polyethyleneterephthalate and polystyrene. These physical or chemical modifications have not yet achieved a satisfactory level of enhancement of the textureability of polypropylene. Considering the importance of BCF polypropylene yarns, in this research, the effect of blending polypropylene with12.5 and 25 % of polyamide 6 on the bulk of the final bulked continuous filament (BCF) yarn has been investigated. The results show that although both crimp contraction and crimp modulus increase with the temperature and pressure of hot air during texturing, but blending polypropylene with even 25% of polyamide 6 does not enhance the textureability of BCF yarns. Also, the reduction in t...
Materials Science and Engineering: C
3D scaffolds are in the center of attention for tissue engineering applications. Whilst many stud... more 3D scaffolds are in the center of attention for tissue engineering applications. Whilst many studies have focused on the biological properties of scaffolds, less attention has been paid to meeting the biomechanics of the target tissues. In this work, we show how using the same original biomaterial, but different fabrication techniques can lead to a broad range of structural, mechanical, and biological characteristics. Starting with silk fibroin filament as our base biomaterial, we employed electrospinning, film casting, and weft knitting as different scaffold fabrication techniques. Among these three, the weft knit scaffold showed outstanding cell-scaffold interaction including full 3D cell attachment, complete cell coverage around individual filaments, and in-depth cell infiltration. Post-fabrication degumming of silk filament yarns resulted in more bulky and less open pores for the silk fibroin knit scaffold. The decreased pore size after degumming of knit scaffold alleviated the need to in-advance pore filling (a requisite for increasing cell adhesion in a typical knit scaffold having big pores). From a mechanical viewpoint, the weft knit scaffold shows the highest mechanical strength alongside with far better extensibility. Interestingly, the silk filament weft knit scaffold (in the course direction) was 100 and 1000 times more compliant than silk fibroin film and electrospun web, respectively. The observed effect of material type and fabrication technique highlights the suitability of silk fibroin weft-knit scaffolds for the regeneration of load-bearing soft tissues such as urine bladder.
Journal of Applied Polymer Science
Diamond and Related Materials, Dec 1, 2021
Polymers for Advanced Technologies, Nov 21, 2021
This study concerns the electrospinning of tragacanth nanofibers containing zinc oxide nanopartic... more This study concerns the electrospinning of tragacanth nanofibers containing zinc oxide nanoparticles with the aim of separating sulfur compounds from crude oil. Zinc oxide incorporated tragacanth nanofibers were electrospun from tragacanth solutions containing zinc oxide nanoparticles with concentrations of 5, 10, 15, and 20 (% w/w). The average diameter of these nanofibers were 91.6, 94.1, 95.4, and 97.8 nm, respectively. SEM images showed that zinc oxide nanoparticles incorporated tragacanth nanofibers were uniformly electrospun with no beads. FTIR analysis showed some interactions between zinc oxide nanoparticles and tragacanth macromolecules. XRD studies showed a two phase microstructure consisting of semi‐crystalline tragacanth matrix with zinc oxide crystallites dispersed in it. The highest filtration efficiency for 300 ml of Isfahan and Gachsaran crude oil was 75.3% and 62.2%, respectively. Moreover, the highest sulfur adsorption capacity obtained for Isfahan and Gachsaran crude oil was 211.20 mg g−1 and 108.19 mg g−1, respectively.
Journal of Inorganic and Organometallic Polymers and Materials, Jun 26, 2020
Journal of environmental chemical engineering, Jun 1, 2022
The Journal of The Textile Institute
International Journal of Biological Macromolecules, Oct 1, 2016
In this study, the fabrication of vanillin incorporated almond gum/polyvinyl alcohol (PVA) nanofi... more In this study, the fabrication of vanillin incorporated almond gum/polyvinyl alcohol (PVA) nanofibers through electrospinning has been investigated. Electrospinning of only almond gum was proved impossible. It was found that the aqueous solution of almond gum/PVA (80:20, concentration=7% (w/w)) containing 3% (w/w) vanillin could have successfully electrospun to uniform nanofibers with diameters as low as 77nm. According to the thermal analysis, incorporated vanillin in almond gum/PVA nanofibers showed higher thermal stability than free vanillin, making this composite especially suitable for high temperature applications. XRD and FTIR analyses proved the presence of vanillin in the almond gum/PVA nanofibers. It was also found that vanillin was dispersed as big crystallites in the matrix of almond gum/PVA nanofibers. FTIR analysis showed almond gum and PVA had chemical cross-linking by etheric bonds between COH groups of almond gum and OH groups of PVA. Also, in the nanofibers, there were no major interaction between vanillin and either almond gum or PVA.
Journal of Applied Polymer Science, 2021
Polymer Bulletin
This article reports the activation of dates stone powder precursor through hydrothermal and dryt... more This article reports the activation of dates stone powder precursor through hydrothermal and drythermal treatments leading to drastic morphological changes in dates stone powder. Depending on the type of activation, spherical or cavernous activated carbon is obtained. Hydrothermal activation brings about a mesoporous structure with average pore diameter of about 32 nm and walls being made of nicely shaped spheres with size in the range of 0.8–1.2 μm. On the other hand, drythermally activated samples show a cavernous structure with rectangular shape pores of around 2–5 μm and walls of about 1.3 μm thickness, being made of very closely packed small spheres. Hydrothermally and drythermally activated samples show a yield of 59.4% and 47.27%, respectively, which is considerably higher than the yield for traditionally activated dates stone. XRD analysis showed a considerably reduced crystallinity for the treated samples. FTIR results confirm the successfully conversion of dates stone into activated carbon. EDX results showed an increased share of carbon from 46.33 to 76.32% and 81.02% for hydrothermal and drythermal samples, respectively. Raman analysis showed a higher order for drythermally activated carbon than hydrothermal one.
Journal of Bioprocessing & Biotechniques, 2015
Copyright © 2014 Fatemeh Ajalloueian et al. This is an open access article distributed under the ... more Copyright © 2014 Fatemeh Ajalloueian et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Novel nanofibers from blends of polylactic-co-glycolic acid (PLGA) and chitosan have been produced through an emulsion electrospinning process. The spinning solution employed polyvinyl alcohol (PVA) as the emulsifier. PVA was extracted from the electrospun nanofibers, resulting in a final scaffold consisting of a blend of PLGA and chitosan.The fraction of chitosan in the final electrospunmat was adjusted from 0 to 33%. Analyses by scanning and transmission electronmicroscopy show uniform nanofibers with homogenous distribution of PLGA and chitosan in their cross section. Infrared spectroscopy verifies that electrospun mats contain both PLGA and chitosan. Moreover, contact angle measurements show that the electrospun PLGA/chitosa...
Journal of Sol-Gel Science and Technology, 2011
Abstract UV radiation causes serious damage to skin, and a protective system capable of absorbing... more Abstract UV radiation causes serious damage to skin, and a protective system capable of absorbing or reflecting UV radiation is required to protect skin. This paper describes the UV protection and photocatalytic properties of TiO2 nanofilm coated electrospun polyacrylonitrile (PAN) ...
ty, and birefringence has been studied by means of polarizing light microscope, DSC and FTIR. Ten... more ty, and birefringence has been studied by means of polarizing light microscope, DSC and FTIR. Tenacity and thermal shrinkage have also been studied. The results indicated that Yellow 83, Blue 15 and Black 7 act as monoclinic nucleating agents, whereas Violet19 and White 6 act as hexagonal nucleating agents. The nucleation effect of Red 48 seems to be negligible. Depending on the type of nucleation, the above mentioned parameters characterizing the microstructure of the fibres are affected. The birefringence of all coloured polypropylene fibres decreased as a result of pigment dyes added to the fibres. This leads to a reduction of the tenacity and thermal shrinkage of mass dyed BCF yarns.
A possibilistic linear regression, i.e. a linear regression with possibilistic coefficients, is e... more A possibilistic linear regression, i.e. a linear regression with possibilistic coefficients, is explained. The application of such possibilistic regression method for modeling of twist liveliness of false twist textured nylon yarns as a function of percentage retraction has been studied, based on a few available data. It turns out that possibilistic regression method is superior to conventional statistical regression, when a very small number of observations are available. In such cases the basic assumptions, under which statistical regression analysis is valid, can not be investigated. Based on some criterions, such as the total vagueness of models and the mean of predictive capabilities, the optimum fuzzy model has been derived.
This paper reports on the effect of fiber crimp frequency on sound absorption capability of stapl... more This paper reports on the effect of fiber crimp frequency on sound absorption capability of staple polypropylene nonwoven batts. Stuffer box was used to impart crimp to spun tow. Crimping of the tow renders the fibers the required textile applicability. In this work, polypropylene batts composed of staple fibers with linear densities of 9, 14, and 18 denier were employed. Three crimp frequency namely low, medium and high were imparted to fibers of each denier group. Impedance tube method with sound frequencies in the range of 250 – 4000 Hz was employed to measure the sound absorption coefficient of the batts. The results showed sound absorption properties of fibrous batts were affected by fiber crimp frequency, fiber fineness and web thickness. The highest sound absorption coefficient for the 9, 14 and 18 denier batts was 78.90, 77.14 and 71.18, respectively. The crimp frequency of the fibers making these batts was 1.9, 2.3 and 3.6 crimp per cm, respectively. It was found that highe...
The Journal of The Textile Institute, 2021
Polypropylene filament yarns, when compared with polyethyleneterephthalate and polyamide yarns ha... more Polypropylene filament yarns, when compared with polyethyleneterephthalate and polyamide yarns have lower stretchability after being false twist textured. To overcome this deficiency, other researchers have tried to lower the degree of crystallinity of this fibre by either tension annealing or blending it with polyethyleneterephthalate and polystyrene. These physical or chemical modifications have not yet achieved a satisfactory level of enhancement of the textureability of polypropylene. Considering the importance of BCF polypropylene yarns, in this research, the effect of blending polypropylene with12.5 and 25 % of polyamide 6 on the bulk of the final bulked continuous filament (BCF) yarn has been investigated. The results show that although both crimp contraction and crimp modulus increase with the temperature and pressure of hot air during texturing, but blending polypropylene with even 25% of polyamide 6 does not enhance the textureability of BCF yarns. Also, the reduction in t...
Materials Science and Engineering: C
3D scaffolds are in the center of attention for tissue engineering applications. Whilst many stud... more 3D scaffolds are in the center of attention for tissue engineering applications. Whilst many studies have focused on the biological properties of scaffolds, less attention has been paid to meeting the biomechanics of the target tissues. In this work, we show how using the same original biomaterial, but different fabrication techniques can lead to a broad range of structural, mechanical, and biological characteristics. Starting with silk fibroin filament as our base biomaterial, we employed electrospinning, film casting, and weft knitting as different scaffold fabrication techniques. Among these three, the weft knit scaffold showed outstanding cell-scaffold interaction including full 3D cell attachment, complete cell coverage around individual filaments, and in-depth cell infiltration. Post-fabrication degumming of silk filament yarns resulted in more bulky and less open pores for the silk fibroin knit scaffold. The decreased pore size after degumming of knit scaffold alleviated the need to in-advance pore filling (a requisite for increasing cell adhesion in a typical knit scaffold having big pores). From a mechanical viewpoint, the weft knit scaffold shows the highest mechanical strength alongside with far better extensibility. Interestingly, the silk filament weft knit scaffold (in the course direction) was 100 and 1000 times more compliant than silk fibroin film and electrospun web, respectively. The observed effect of material type and fabrication technique highlights the suitability of silk fibroin weft-knit scaffolds for the regeneration of load-bearing soft tissues such as urine bladder.
Journal of Applied Polymer Science