Turkish textile firms work under a heavily competitive atmosphere in terms of prices due to globa... more Turkish textile firms work under a heavily competitive atmosphere in terms of prices due to globalisation. Firms have to take into consideration several criteria in order to survive the global market conditions and to maintain profitability. Contractor companies have to select the optimal subcontractor in order to meet these criteria and in business. Therefore the decision to choose subcontractors is of great importance for the success of enterprises. In solving the problem of subcontractor selection, multiple criteria should be considered, for which multi-criteria decision-making methods are used. This paper presents a case study which regards the selection of the optimal subcontractor for a Turkish textile firm. In order to solve the selection problem generalized Choquet integral methodology was used based on a hierarchical decision model. In the conclusion section of the study, optimal subcontractor selection results are presented.
Flexible strain sensitive electrospun fibrous layers have attracted widespread attention of resea... more Flexible strain sensitive electrospun fibrous layers have attracted widespread attention of researchers owing to their large surface area and exceptional flexibility. Herein, a detailed research on the impact of electrospinning parameters on the morphological and electromechanical properties of electrospun multiwalled carbon nanotubes (MWCNTs)/thermoplastic polyurethane (TPU) nanofibers is conducted. Besides the MWCNTs concentrations, electrospinning parameters have a significant effect on the morphology, electromechanical and sensory properties of electrospun MWCNTs/TPU nanofibrous membrane. Results show that at lower collector speeds, tip to collector distances, and higher electrospinning time lead to the formation of more homogeneously dispersed fibrous structures, which result in enhanced conductivity and strain sensitivity. Consequently, from the repeatability tests, all samples show quite similar linear responses under strain, indicating a highly repeatable fabrication process. Obtained results can help to gain a deeper understanding of the importance of controlling the electrospinning parameters, especially in the production of flexible strain sensors. Graphical Abstract
In this study, graphene oxide (GO) was synthesized from naturel graphite powder by using modified... more In this study, graphene oxide (GO) was synthesized from naturel graphite powder by using modified Hummer's method. In comparison to the Hummer's method, modified Hummer’s method is safer and more eco-friendly. At the SEM images, foliated and ultrathin GO structures were observed. Oxygen content of about 23.60 % determined through by EDX showed the occurrence of the oxidation process. Moreover, the thermal stability of the GO structure could be identified from the TGA analysis. The 2θ peak value in XRD was found to be at 10.5524°. In addition, the characteristic peaks of the GO were observed on the FT-IR and Raman spectroscopies. These results depicted that the GO was successfully synthesized from graphite powder by using the modified Hummer's method.
2015 IEEE International Conference on Fuzzy Systems (FUZZ-IEEE), 2015
The supplier selection process of a company depends on numerous criteria which can have differing... more The supplier selection process of a company depends on numerous criteria which can have differing importance factors. Solving this kind of multiple criteria decision making (MCDM) problem is essential for the long-term strategy of a company. While this problem is examined numerous times throughout the years, the consideration of involving economic, social and environmental factors, i.e. sustainability is becoming a growing necessity for this effort, especially in the recent years. We propose a Choquet integral based fuzzy model to use the data we obtain by converting the linguistic terms of perceived subcontractor performance values to trapezoidal fuzzy numbers. After the performance criteria values are normalized by the fuzzy integral, they are defuzzified into single data points which helps an evaluator to compare. A case study involving a curtain wall company in Turkey (and its 4 subcontractors) is used to demonstrate the effectiveness of the method. The defuzzified results showed which subcontractor is the optimal choice among 4 subcontractors and 17 criteria.
Flexible strain sensitive electrospun fibrous layers have attracted widespread attention of resea... more Flexible strain sensitive electrospun fibrous layers have attracted widespread attention of researchers owing to their large surface area and exceptional flexibility. Herein, a detailed research on the impact of electrospinning parameters on the morphological and electromechanical properties of electrospun multiwalled carbon nanotubes (MWCNTs)/thermoplastic polyurethane (TPU) nanofibers is conducted. Besides the MWCNTs concentrations, electrospinning parameters have a significant effect on the morphology, electromechanical and sensory properties of electrospun MWCNTs/TPU nanofibrous membrane. Results show that at lower collector speeds, tip to collector distances, and higher electrospinning time lead to the formation of more homogeneously dispersed fibrous structures, which result in enhanced conductivity and strain sensitivity. Consequently, from the repeatability tests, all samples show quite similar linear responses under strain, indicating a highly repeatable fabrication process. Obtained results can help to gain a deeper understanding of the importance of controlling the electrospinning parameters, especially in the production of flexible strain sensors. Graphical Abstract
International Journal of Advances in Engineering and Pure Sciences, 2019
Alginate is a biomaterial that is used in food, textile and medical industry. Alginate is used in... more Alginate is a biomaterial that is used in food, textile and medical industry. Alginate is used in textile industry as sizing agent, thickener and finishing materials.In addition to this, it is used in medical industry due to its biodegradable and biocompatible properties. The aim of this study is to investigate the antimicrobial properties of Ag–alginate impregnated polyester/viscose nonwoven fabric. In this study, Ag–alginate solutions were prepared. Polyester/viscose nonwoven fabric with different mixing ratio was impregnated with prepared solutions. Finally, The antimicrobial, EDX and SEM analyses were performed.
In this study, graphene oxide (GO) was synthesized from graphite using modified Hummers method. A... more In this study, graphene oxide (GO) was synthesized from graphite using modified Hummers method. According to other methods known in the literature, modified Hummers method; it is simpler and less costly in terms of process steps. In addition, it is safer and environmentally friendly than the Hummers method. Reduced Graphene Oxide (RGO) was obtained by reduction of graphene oxides (GO) synthesized by modified Hummers method. It is understood from the obtained results that GO is synthesized successfully from graphite powder by modified Hummers method and RGO is obtained successfully by reduction of graphene oxides (GO).
ÖZ
Bu çalışmada modifiye Hummers yöntemi kullanılarak grafitten grafen oksit (GO) sentezlenmişti... more ÖZ Bu çalışmada modifiye Hummers yöntemi kullanılarak grafitten grafen oksit (GO) sentezlenmiştir. Literatürde bilinen diğer yöntemlere göre modifiye Hummers yöntemi; işlem basamakları açısından daha basit ve düşük maliyetlidir. Ayrıca Hummers yöntemine göre daha tehlikesiz ve daha çevre dostu bir yöntemdir. SEM görüntülerinde katmanlı ve çok ince GO yapıları gözlenmiştir. EDX/SEM Elementel analizde oksijen (O) oranının yaklaşık %23,60 olması oksidasyon işleminin gerçekleştiğini göstermektedir. GO yapısının termal kararlılığı TGA analizinden anlaşılmaktadır. XRD analizinde 2θ piki, 10,5524° de elde edilmiştir. Ayrıca, FT-IR spektroskopisi ve Raman spektroskopisinde ise GO'ya ait karakteristik pikler görülmüştür. Elde edilen sonuçlardan modifiye Hummers yöntemi ile grafit tozundan başarılı bir şekilde GO sentezlendiği anlaşılmaktadır.
Turkish textile firms work under a heavily competitive atmosphere in terms of prices due to globa... more Turkish textile firms work under a heavily competitive atmosphere in terms of prices due to globalisation. Firms have to take into consideration several criteria in order to survive the global market conditions and to maintain profitability. Contractor companies have to select the optimal subcontractor in order to meet these criteria and in business. Therefore the decision to choose subcontractors is of great importance for the success of enterprises. In solving the problem of subcontractor selection, multiple criteria should be considered, for which multi-criteria decision-making methods are used. This paper presents a case study which regards the selection of the optimal subcontractor for a Turkish textile firm. In order to solve the selection problem generalized Choquet integral methodology was used based on a hierarchical decision model. In the conclusion section of the study, optimal subcontractor selection results are presented.
Flexible strain sensitive electrospun fibrous layers have attracted widespread attention of resea... more Flexible strain sensitive electrospun fibrous layers have attracted widespread attention of researchers owing to their large surface area and exceptional flexibility. Herein, a detailed research on the impact of electrospinning parameters on the morphological and electromechanical properties of electrospun multiwalled carbon nanotubes (MWCNTs)/thermoplastic polyurethane (TPU) nanofibers is conducted. Besides the MWCNTs concentrations, electrospinning parameters have a significant effect on the morphology, electromechanical and sensory properties of electrospun MWCNTs/TPU nanofibrous membrane. Results show that at lower collector speeds, tip to collector distances, and higher electrospinning time lead to the formation of more homogeneously dispersed fibrous structures, which result in enhanced conductivity and strain sensitivity. Consequently, from the repeatability tests, all samples show quite similar linear responses under strain, indicating a highly repeatable fabrication process. Obtained results can help to gain a deeper understanding of the importance of controlling the electrospinning parameters, especially in the production of flexible strain sensors. Graphical Abstract
In this study, graphene oxide (GO) was synthesized from naturel graphite powder by using modified... more In this study, graphene oxide (GO) was synthesized from naturel graphite powder by using modified Hummer's method. In comparison to the Hummer's method, modified Hummer’s method is safer and more eco-friendly. At the SEM images, foliated and ultrathin GO structures were observed. Oxygen content of about 23.60 % determined through by EDX showed the occurrence of the oxidation process. Moreover, the thermal stability of the GO structure could be identified from the TGA analysis. The 2θ peak value in XRD was found to be at 10.5524°. In addition, the characteristic peaks of the GO were observed on the FT-IR and Raman spectroscopies. These results depicted that the GO was successfully synthesized from graphite powder by using the modified Hummer's method.
2015 IEEE International Conference on Fuzzy Systems (FUZZ-IEEE), 2015
The supplier selection process of a company depends on numerous criteria which can have differing... more The supplier selection process of a company depends on numerous criteria which can have differing importance factors. Solving this kind of multiple criteria decision making (MCDM) problem is essential for the long-term strategy of a company. While this problem is examined numerous times throughout the years, the consideration of involving economic, social and environmental factors, i.e. sustainability is becoming a growing necessity for this effort, especially in the recent years. We propose a Choquet integral based fuzzy model to use the data we obtain by converting the linguistic terms of perceived subcontractor performance values to trapezoidal fuzzy numbers. After the performance criteria values are normalized by the fuzzy integral, they are defuzzified into single data points which helps an evaluator to compare. A case study involving a curtain wall company in Turkey (and its 4 subcontractors) is used to demonstrate the effectiveness of the method. The defuzzified results showed which subcontractor is the optimal choice among 4 subcontractors and 17 criteria.
Flexible strain sensitive electrospun fibrous layers have attracted widespread attention of resea... more Flexible strain sensitive electrospun fibrous layers have attracted widespread attention of researchers owing to their large surface area and exceptional flexibility. Herein, a detailed research on the impact of electrospinning parameters on the morphological and electromechanical properties of electrospun multiwalled carbon nanotubes (MWCNTs)/thermoplastic polyurethane (TPU) nanofibers is conducted. Besides the MWCNTs concentrations, electrospinning parameters have a significant effect on the morphology, electromechanical and sensory properties of electrospun MWCNTs/TPU nanofibrous membrane. Results show that at lower collector speeds, tip to collector distances, and higher electrospinning time lead to the formation of more homogeneously dispersed fibrous structures, which result in enhanced conductivity and strain sensitivity. Consequently, from the repeatability tests, all samples show quite similar linear responses under strain, indicating a highly repeatable fabrication process. Obtained results can help to gain a deeper understanding of the importance of controlling the electrospinning parameters, especially in the production of flexible strain sensors. Graphical Abstract
International Journal of Advances in Engineering and Pure Sciences, 2019
Alginate is a biomaterial that is used in food, textile and medical industry. Alginate is used in... more Alginate is a biomaterial that is used in food, textile and medical industry. Alginate is used in textile industry as sizing agent, thickener and finishing materials.In addition to this, it is used in medical industry due to its biodegradable and biocompatible properties. The aim of this study is to investigate the antimicrobial properties of Ag–alginate impregnated polyester/viscose nonwoven fabric. In this study, Ag–alginate solutions were prepared. Polyester/viscose nonwoven fabric with different mixing ratio was impregnated with prepared solutions. Finally, The antimicrobial, EDX and SEM analyses were performed.
In this study, graphene oxide (GO) was synthesized from graphite using modified Hummers method. A... more In this study, graphene oxide (GO) was synthesized from graphite using modified Hummers method. According to other methods known in the literature, modified Hummers method; it is simpler and less costly in terms of process steps. In addition, it is safer and environmentally friendly than the Hummers method. Reduced Graphene Oxide (RGO) was obtained by reduction of graphene oxides (GO) synthesized by modified Hummers method. It is understood from the obtained results that GO is synthesized successfully from graphite powder by modified Hummers method and RGO is obtained successfully by reduction of graphene oxides (GO).
ÖZ
Bu çalışmada modifiye Hummers yöntemi kullanılarak grafitten grafen oksit (GO) sentezlenmişti... more ÖZ Bu çalışmada modifiye Hummers yöntemi kullanılarak grafitten grafen oksit (GO) sentezlenmiştir. Literatürde bilinen diğer yöntemlere göre modifiye Hummers yöntemi; işlem basamakları açısından daha basit ve düşük maliyetlidir. Ayrıca Hummers yöntemine göre daha tehlikesiz ve daha çevre dostu bir yöntemdir. SEM görüntülerinde katmanlı ve çok ince GO yapıları gözlenmiştir. EDX/SEM Elementel analizde oksijen (O) oranının yaklaşık %23,60 olması oksidasyon işleminin gerçekleştiğini göstermektedir. GO yapısının termal kararlılığı TGA analizinden anlaşılmaktadır. XRD analizinde 2θ piki, 10,5524° de elde edilmiştir. Ayrıca, FT-IR spektroskopisi ve Raman spektroskopisinde ise GO'ya ait karakteristik pikler görülmüştür. Elde edilen sonuçlardan modifiye Hummers yöntemi ile grafit tozundan başarılı bir şekilde GO sentezlendiği anlaşılmaktadır.
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Bu çalışmada modifiye Hummers yöntemi kullanılarak grafitten grafen oksit (GO) sentezlenmiştir. Literatürde bilinen diğer yöntemlere göre modifiye Hummers yöntemi; işlem basamakları açısından daha basit ve düşük maliyetlidir. Ayrıca Hummers yöntemine göre daha tehlikesiz ve daha çevre dostu bir yöntemdir. SEM görüntülerinde katmanlı ve çok ince GO yapıları gözlenmiştir. EDX/SEM Elementel analizde oksijen (O) oranının yaklaşık %23,60 olması oksidasyon işleminin gerçekleştiğini göstermektedir. GO yapısının termal kararlılığı TGA analizinden anlaşılmaktadır. XRD analizinde 2θ piki, 10,5524° de elde edilmiştir. Ayrıca, FT-IR spektroskopisi ve Raman spektroskopisinde ise GO'ya ait karakteristik pikler görülmüştür. Elde edilen sonuçlardan modifiye Hummers yöntemi ile grafit tozundan başarılı bir şekilde GO sentezlendiği anlaşılmaktadır.
Bu çalışmada modifiye Hummers yöntemi kullanılarak grafitten grafen oksit (GO) sentezlenmiştir. Literatürde bilinen diğer yöntemlere göre modifiye Hummers yöntemi; işlem basamakları açısından daha basit ve düşük maliyetlidir. Ayrıca Hummers yöntemine göre daha tehlikesiz ve daha çevre dostu bir yöntemdir. SEM görüntülerinde katmanlı ve çok ince GO yapıları gözlenmiştir. EDX/SEM Elementel analizde oksijen (O) oranının yaklaşık %23,60 olması oksidasyon işleminin gerçekleştiğini göstermektedir. GO yapısının termal kararlılığı TGA analizinden anlaşılmaktadır. XRD analizinde 2θ piki, 10,5524° de elde edilmiştir. Ayrıca, FT-IR spektroskopisi ve Raman spektroskopisinde ise GO'ya ait karakteristik pikler görülmüştür. Elde edilen sonuçlardan modifiye Hummers yöntemi ile grafit tozundan başarılı bir şekilde GO sentezlendiği anlaşılmaktadır.