Estimating effects of drugs at different stages is directly proportional to the duration of recovery and duration of pulling through with the disease. For this reason, solving Pharmacokinetic models that investigate these effects is very important. In this study, numerical solutions of this type of one, two and three compartment nonlinear Pharmacokinetic models have been studied. Distributed order differential equations are used for the solution of the model. Numerical solutions have been found with the density function contained in distributed order differential equations and different values of this function. A Nonstandard finite difference scheme has been used for numerical solutions. Finally, stability analysis of equilibrium points of obtained discretized system has also been expressed with the help of the Schur-Cohn criteria.
{"title":"Discretization and Stability Analysis for a Generalized Type Nonlinear Pharmacokinetic Models","authors":"M. Kocabiyik, Mevlüde YAKIT ONGUN","doi":"10.35378/gujs.1027381","DOIUrl":"https://doi.org/10.35378/gujs.1027381","url":null,"abstract":"Estimating effects of drugs at different stages is directly proportional to the duration of recovery and duration of pulling through with the disease. For this reason, solving Pharmacokinetic models that investigate these effects is very important. In this study, numerical solutions of this type of one, two and three compartment nonlinear Pharmacokinetic models have been studied. Distributed order differential equations are used for the solution of the model. Numerical solutions have been found with the density function contained in distributed order differential equations and different values of this function. A Nonstandard finite difference scheme has been used for numerical solutions. Finally, stability analysis of equilibrium points of obtained discretized system has also been expressed with the help of the Schur-Cohn criteria.","PeriodicalId":12615,"journal":{"name":"gazi university journal of science","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44032004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This article presents the buckling behavior of carbon nanotubes reinforced sandwich-structured composite shells supported by elastic foundations. The sandwich-structured configuration is composed of three layers, an isotropic core, and two nanocomposite face sheets. Carbon nanotubes fibers are applied to reinforce nanocomposite face sheets of sandwich composite shells. It is assumed that the distribution of reinforcements across the shell thickness is uniform or functionally graded. Under the assumption of the thin shell, the equilibrium equation of the buckling response of CNT-RSSC shells is obtained. The pre-buckling stresses by applying Airy’s stress function and an adjacent equilibrium criterion to establish the stability equation associated with the buckling state are obtained. The effects of different types of CNTs' reinforcement, volume fractions, geometrical parameters, core to face sheet thickness ratio, and elastic foundations on the mechanical buckling analysis are examined.
{"title":"Analytical modeling of buckling of carbon nanotubes reinforced sandwich-structured composite shells resting on elastic foundations","authors":"A. Timesli","doi":"10.35378/gujs.998265","DOIUrl":"https://doi.org/10.35378/gujs.998265","url":null,"abstract":"This article presents the buckling behavior of carbon nanotubes reinforced sandwich-structured composite shells supported by elastic foundations. The sandwich-structured configuration is composed of three layers, an isotropic core, and two nanocomposite face sheets. Carbon nanotubes fibers are applied to reinforce nanocomposite face sheets of sandwich composite shells. It is assumed that the distribution of reinforcements across the shell thickness is uniform or functionally graded. Under the assumption of the thin shell, the equilibrium equation of the buckling response of CNT-RSSC shells is obtained. The pre-buckling stresses by applying Airy’s stress function and an adjacent equilibrium criterion to establish the stability equation associated with the buckling state are obtained. The effects of different types of CNTs' reinforcement, volume fractions, geometrical parameters, core to face sheet thickness ratio, and elastic foundations on the mechanical buckling analysis are examined.","PeriodicalId":12615,"journal":{"name":"gazi university journal of science","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43783134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Glazed curtain wall systems have become indispensable particularly in office buildings due to their light weight, aesthetic appearance, easy installation and resistance to climate conditions. Curtain walls however, also have problems in terms of thermal efficiency because of their wide, glazing windows and metal frames that have high thermal conductivity. The aim of this study is to offer proposals for improving the thermal performance of an office building with a glass curtain wall system built in a hot-humid climate zone. An office building constructed in Antalya, Turkey was modelled with the help of DesignBuilder energy simulation software and various modifications were made on the model in order to improve the thermal performance of the building. With the improvements proposed in the study, it is possible to decrease the annual thermal loads of the whole building by 6.6%, and the annual thermal loads of the space with the curtain wall by 33.2%. The study revealed that, applying an additional envelope is more effective than lowering the U-value of the glass of the curtain wall in terms of thermal performance improvement.
{"title":"Recommendations for Improvement of the Thermal Performance of an Office Building Based on Retrofitting the Glazed Curtain Wall","authors":"Neşe Di̇kmen, Canan Altundaş","doi":"10.35378/gujs.997496","DOIUrl":"https://doi.org/10.35378/gujs.997496","url":null,"abstract":"Glazed curtain wall systems have become indispensable particularly in office buildings due to their light weight, aesthetic appearance, easy installation and resistance to climate conditions. Curtain walls however, also have problems in terms of thermal efficiency because of their wide, glazing windows and metal frames that have high thermal conductivity. The aim of this study is to offer proposals for improving the thermal performance of an office building with a glass curtain wall system built in a hot-humid climate zone. An office building constructed in Antalya, Turkey was modelled with the help of DesignBuilder energy simulation software and various modifications were made on the model in order to improve the thermal performance of the building. With the improvements proposed in the study, it is possible to decrease the annual thermal loads of the whole building by 6.6%, and the annual thermal loads of the space with the curtain wall by 33.2%. The study revealed that, applying an additional envelope is more effective than lowering the U-value of the glass of the curtain wall in terms of thermal performance improvement.","PeriodicalId":12615,"journal":{"name":"gazi university journal of science","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46020440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, powder metal samples of 15x15x4 mm dimensions of Fe powders were produced at different pressures (650,850,1050 MPa) and were sintered in atmospheric environment with the help of resistance sintering method applied for the first time using electric resistance welding. The sintered and green densities of the powder metal samples were measured and their sinterability in the unprotected environment was examined. Powder metal specimens were sintered successfully with the electric resistance welding technique in an unprotected environment and high density values such as 98% were obtained. In addition, the effects of electric resistance heating technique on sintering were investigated by performing hardness analysis and microscopic examination of sintered samples.
{"title":"Sintering of Iron Powders by Resistance Heating Technique","authors":"F. Atar, A. Kurt","doi":"10.35378/gujs.1003395","DOIUrl":"https://doi.org/10.35378/gujs.1003395","url":null,"abstract":"In this study, powder metal samples of 15x15x4 mm dimensions of Fe powders were produced at different pressures (650,850,1050 MPa) and were sintered in atmospheric environment with the help of resistance sintering method applied for the first time using electric resistance welding. The sintered and green densities of the powder metal samples were measured and their sinterability in the unprotected environment was examined. Powder metal specimens were sintered successfully with the electric resistance welding technique in an unprotected environment and high density values such as 98% were obtained. In addition, the effects of electric resistance heating technique on sintering were investigated by performing hardness analysis and microscopic examination of sintered samples.","PeriodicalId":12615,"journal":{"name":"gazi university journal of science","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45843692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, definitions of Weld Penetration (WP), Depth of Fusion (DOF) and Throat Thickness (TT) in fillet welds according to related standards are reviewed. WP, DOF and TT are crucial dimensions for welded joints since these values determine the weld quality. In AWS A3.0, ISO2553, Eurocode EN 1993-1-8 and DIN EN ISO 17659, these terms are defined, explained and shown in figures. Each standard makes its own definition related with WP, DOF and TT. Moreover, when looking at these standards, it is seen that definitions are always made in terms of unit of length. In some studies, assessment of fusion or penetration (FOP) rate on fillet welds is performed as the ratio of the maximum FOP depth to the material thickness. Depth assessment taking into consideration unit of length is not ideal for accurate evaluation of FOP rates especially on fillet welds. Method taking into consideration unit of area will be more suitable as it allows accurate assessment of FOP rates in welded joints. In this review, it is also suggested that the evaluation of FOP rate on fillet welds should be determined in terms of unit of area rather than length.
本文综述了相关标准对角焊缝熔深(WP)、熔深(DOF)和喉道厚度(TT)的定义。WP, DOF和TT是焊接接头的关键尺寸，因为这些值决定了焊接质量。在AWS A3.0、ISO2553、欧洲规范EN 1993-1-8和DIN EN ISO 17659中，这些术语用图表进行了定义、解释和显示。每个标准对WP、DOF和TT都有自己的定义。此外，当查看这些标准时，可以看到定义总是根据长度单位进行的。在一些研究中，用最大熔透深度与材料厚度之比来评估角焊缝的熔透率。考虑长度单位的深度评估对于准确评估FOP率并不理想，尤其是在角焊缝上。考虑面积单位的方法更合适，因为它可以准确地评估焊接接头的FOP率。在这篇综述中，还建议评价角焊缝的FOP率应以单位面积而不是长度来确定。
{"title":"Review of the Definition of Weld Penetration, Depth of Fusion and Throat Thickness on Fillet Welds","authors":"Umut Yaşar Uzunali, H. Çuvalcı","doi":"10.35378/gujs.1137178","DOIUrl":"https://doi.org/10.35378/gujs.1137178","url":null,"abstract":"In this study, definitions of Weld Penetration (WP), Depth of Fusion (DOF) and Throat Thickness (TT) in fillet welds according to related standards are reviewed. WP, DOF and TT are crucial dimensions for welded joints since these values determine the weld quality. In AWS A3.0, ISO2553, Eurocode EN 1993-1-8 and DIN EN ISO 17659, these terms are defined, explained and shown in figures. Each standard makes its own definition related with WP, DOF and TT. Moreover, when looking at these standards, it is seen that definitions are always made in terms of unit of length. In some studies, assessment of fusion or penetration (FOP) rate on fillet welds is performed as the ratio of the maximum FOP depth to the material thickness. Depth assessment taking into consideration unit of length is not ideal for accurate evaluation of FOP rates especially on fillet welds. Method taking into consideration unit of area will be more suitable as it allows accurate assessment of FOP rates in welded joints. In this review, it is also suggested that the evaluation of FOP rate on fillet welds should be determined in terms of unit of area rather than length.","PeriodicalId":12615,"journal":{"name":"gazi university journal of science","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48735302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, hydrogen diffusion profiles of different metallic materials were investigated. To model hydrogen diffusion, 1D and 2D mass diffusion models were prepared in MATLAB. Iron, nickel and titanium were selected as a material of choice to represent body-centered cubic, face-centered cubic, and hexagonal closed paced crystal structures, respectively. In addition, hydrogen back diffusion profiles were also modeled after certain baking times. Current results reveal that hydrogen diffusion depth depends on the microstructure, energy barrier model, temperature, and charging time. In addition, baking can help for back diffusion of hydrogen and can be utilized as hydrogen embrittlement prevention method. Since hydrogen diffusion is very crucial step to understand and evaluate hydrogen embrittlement, current set of results constitutes an important guideline for hydrogen diffusion calculations and ideal baking time for hydrogen back diffusion for different materials. Furthermore, these results can be used to evaluate hydrogen content inside the material over expensive and hard to find experimental facilities such as, thermal desorption spectroscopy.
{"title":"Investigation of Hydrogen Diffusion Profile of Different Metallic Materials for a Better Understanding of Hydrogen Embrittlement","authors":"M. F. Kapci, B. Bal","doi":"10.35378/gujs.1090824","DOIUrl":"https://doi.org/10.35378/gujs.1090824","url":null,"abstract":"In this study, hydrogen diffusion profiles of different metallic materials were investigated. To model hydrogen diffusion, 1D and 2D mass diffusion models were prepared in MATLAB. Iron, nickel and titanium were selected as a material of choice to represent body-centered cubic, face-centered cubic, and hexagonal closed paced crystal structures, respectively. In addition, hydrogen back diffusion profiles were also modeled after certain baking times. Current results reveal that hydrogen diffusion depth depends on the microstructure, energy barrier model, temperature, and charging time. In addition, baking can help for back diffusion of hydrogen and can be utilized as hydrogen embrittlement prevention method. Since hydrogen diffusion is very crucial step to understand and evaluate hydrogen embrittlement, current set of results constitutes an important guideline for hydrogen diffusion calculations and ideal baking time for hydrogen back diffusion for different materials. Furthermore, these results can be used to evaluate hydrogen content inside the material over expensive and hard to find experimental facilities such as, thermal desorption spectroscopy.","PeriodicalId":12615,"journal":{"name":"gazi university journal of science","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69795962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, carbon monoxide methanation was investigated with 15 %NiO doped SAPO34 zeolite supported catalysts. The SAPO34 support was produced by hydrothermal synthesis, and nickeloxide was added to the support by impregnation and surfactant impregnation method by using different solvents (water, ethanol, acetone and 1-propanol). Various characterization techniques were used to determine the physical properties of catalysts and support (N2 physisorption, XRD, SEM, TEM, FTIR). XRD analysis showed that synthesizing the catalysts with surfactant reduced the average crystal size. The average crystal sizes of the catalysts prepared by the impregnation and surfactant assisted impregnation methods are between 11.3-7.1 nm and 8.9-7.1 nm, respectievely. N2 physisorption analysis showed that catalysts prepared by the surfactant-assisted impregnation method had higher surface areas than the catalysts prepared by the classical impregnation method. It was observed that the surface area of the catalyst increased as the boiling point of the solvent increased. Scanning electron microscopy (SEM) analysis showed that particle size of the catalysts with propanol prepared by impregnation and surfactant assisted impregnation methods are 118 nm and 86 nm, respectievely. Surfactant caused to produce smaller particles. The CO methanation studies showed that highest CO conversion values were reached with Ni/SAPO34 catalyst using 1-propanol prepared by impregnation and surfactant assisted impregnation methods which gave 19.2% and 21.1% CO conversion to methane at 375C, respectievely The low methane formation rates showed that most of the CO component was adsorbed on the surface and some of it was converted to methane.
{"title":"CO Methanation Over SAPO-34 Supported Ni Catalysts","authors":"Filiz BALIKÇI DEREKAYA, Y. Kilinç","doi":"10.35378/gujs.1125710","DOIUrl":"https://doi.org/10.35378/gujs.1125710","url":null,"abstract":"In this study, carbon monoxide methanation was investigated with 15 %NiO doped SAPO34 zeolite supported catalysts. The SAPO34 support was produced by hydrothermal synthesis, and nickeloxide was added to the support by impregnation and surfactant impregnation method by using different solvents (water, ethanol, acetone and 1-propanol). Various characterization techniques were used to determine the physical properties of catalysts and support (N2 physisorption, XRD, SEM, TEM, FTIR). XRD analysis showed that synthesizing the catalysts with surfactant reduced the average crystal size. The average crystal sizes of the catalysts prepared by the impregnation and surfactant assisted impregnation methods are between 11.3-7.1 nm and 8.9-7.1 nm, respectievely. N2 physisorption analysis showed that catalysts prepared by the surfactant-assisted impregnation method had higher surface areas than the catalysts prepared by the classical impregnation method. It was observed that the surface area of the catalyst increased as the boiling point of the solvent increased. Scanning electron microscopy (SEM) analysis showed that particle size of the catalysts with propanol prepared by impregnation and surfactant assisted impregnation methods are 118 nm and 86 nm, respectievely. Surfactant caused to produce smaller particles. The CO methanation studies showed that highest CO conversion values were reached with Ni/SAPO34 catalyst using 1-propanol prepared by impregnation and surfactant assisted impregnation methods which gave 19.2% and 21.1% CO conversion to methane at 375C, respectievely The low methane formation rates showed that most of the CO component was adsorbed on the surface and some of it was converted to methane.","PeriodicalId":12615,"journal":{"name":"gazi university journal of science","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42808765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Metallic-intermetallic laminate (MIL) composites possess intermediary properties emerging from the different laminates used. They are anisotropic since their properties are direction dependent. The laminates used in a MIL composite have different thermal conductivities and this results in anisotropic thermal resistance. In a recent study, using the composite dimensions and the electrical conductivity of the laminates used to make the MIL composite, the electrical resistance of rectangular prism-shaped MIL composites for different directions is examined. Since thermal and electrical circuits are analogues, a similar analysis can also be done for thermal conduction quantities. In this study, using the composite dimensions and the thermal conductivity of the laminates used to make the MIL composite, the thermal resistance of rectangular prism-shaped MIL composites for different directions is calculated and its direction-dependent parametric examination are made.
{"title":"Parametric Examination Anisotropic Thermal Resistance of MIL Composites","authors":"Kübra Solak, R. Mutlu","doi":"10.35378/gujs.1122095","DOIUrl":"https://doi.org/10.35378/gujs.1122095","url":null,"abstract":"Metallic-intermetallic laminate (MIL) composites possess intermediary properties emerging from the different laminates used. They are anisotropic since their properties are direction dependent. The laminates used in a MIL composite have different thermal conductivities and this results in anisotropic thermal resistance. In a recent study, using the composite dimensions and the electrical conductivity of the laminates used to make the MIL composite, the electrical resistance of rectangular prism-shaped MIL composites for different directions is examined. Since thermal and electrical circuits are analogues, a similar analysis can also be done for thermal conduction quantities. In this study, using the composite dimensions and the thermal conductivity of the laminates used to make the MIL composite, the thermal resistance of rectangular prism-shaped MIL composites for different directions is calculated and its direction-dependent parametric examination are made.","PeriodicalId":12615,"journal":{"name":"gazi university journal of science","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48680787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Olga Nehir Öztel, H. Yilmaz, I. A. Işoğlu, A. Allahverdiyev
It is increasingly becoming important to develop three-dimensional (3-D) cell culture systems due to their numerous advantages over traditional monolayer culture. The aim of this study is to investigate the interaction of adipose derived stem cells (ADSCs) with scaffolds composed of ε-polycaprolactone (ε-PCL) and egg white. In our study; ε-PCL and egg white scaffolds were fabricated from their monomers under the catalysis of tin octoate and by polymerization by heat respectively. Characterization of PCL was carried out with Gel permeability chromatography (GPC), Fourier Transform Infrared Spectrophotometry (FTIR), Proton Nuclear Magnetic Resonance (H-NMR), Differential Scan Calorimetry (DSC) and Scanning Electron Microscopy (SEM). CM-DiI labeled ADSCs were cultured for 12 days on egg white and ε-PCL scaffolds. Cell viability was performed using MTT and nitric oxide level was evaluated for toxicity. Results showed that the number of ADSCs on egg white scaffold increased periodically throughout 12 days compared with the other groups. Although the number of ADSCs on ε-PCL scaffold increased until the 6th day of the culture, the cell number began to decrease after day 6.. These results were associated with the decomposition of PCL scaffolds that occurs through catabolic reactions. This causes the release of lactic acid which makes toxic effect on the cells. Thus, these results showed that egg white scaffold increases and protects cell adhesion and cell viability more than ε-Polycaprolactone scaffold, thus it can be used as a scaffold in tissue engineering studies that involve stem cells.
{"title":"COMPARİSON OF EGG WHİTE AND Ε-POLYCAPROLACTONE FOR THREE-DİMENSİONAL CELL CULTURE","authors":"Olga Nehir Öztel, H. Yilmaz, I. A. Işoğlu, A. Allahverdiyev","doi":"10.35378/gujs.1037746","DOIUrl":"https://doi.org/10.35378/gujs.1037746","url":null,"abstract":"It is increasingly becoming important to develop three-dimensional (3-D) cell culture systems due to their numerous advantages over traditional monolayer culture. The aim of this study is to investigate the interaction of adipose derived stem cells (ADSCs) with scaffolds composed of ε-polycaprolactone (ε-PCL) and egg white. In our study; ε-PCL and egg white scaffolds were fabricated from their monomers under the catalysis of tin octoate and by polymerization by heat respectively. Characterization of PCL was carried out with Gel permeability chromatography (GPC), Fourier Transform Infrared Spectrophotometry (FTIR), Proton Nuclear Magnetic Resonance (H-NMR), Differential Scan Calorimetry (DSC) and Scanning Electron Microscopy (SEM). CM-DiI labeled ADSCs were cultured for 12 days on egg white and ε-PCL scaffolds. Cell viability was performed using MTT and nitric oxide level was evaluated for toxicity. Results showed that the number of ADSCs on egg white scaffold increased periodically throughout 12 days compared with the other groups. Although the number of ADSCs on ε-PCL scaffold increased until the 6th day of the culture, the cell number began to decrease after day 6.. These results were associated with the decomposition of PCL scaffolds that occurs through catabolic reactions. This causes the release of lactic acid which makes toxic effect on the cells. Thus, these results showed that egg white scaffold increases and protects cell adhesion and cell viability more than ε-Polycaprolactone scaffold, thus it can be used as a scaffold in tissue engineering studies that involve stem cells.","PeriodicalId":12615,"journal":{"name":"gazi university journal of science","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41286769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Ayyıldız, Gökhan Özçelik, Cevriye Gencer, E. Demirci
This paper defines a capacitated multiple-source multiple-sink shortest path problem and introduces its extension, called the capacitated multiple-source multiple-sink shortest path network interdiction problem (CMSSNIP). CMSSNIP examines the actions of attackers who attempt to maximize the total shortest path of network users trying to reach the crime locations for the aid process after causing an incident in certain regions to provide strategic information for the defense systems of the government. In this context, the exact mathematical model ensuring useful information about safe routes to network users is proposed. In this manner, to the best knowledge of authors, the CMSSNIP consisting of multiple-source nodes and multiple-sink nodes and considering capacity-demand relations between security units and crime locations is studied for the first time. Accordingly, a set of scenarios is considered based on the interdiction budget levels and the number of crime locations through a real case application to show the applicability of the model. Furthermore, computational experiments are performed to evaluate the model performance on different-sized networks. It is realized that especially the model provides resilient strategies versus interdictions in terms of obtaining the safe shortest paths at the operational level within seconds in the real case application.
{"title":"Providing homeland security strategies against interdictions in the city transportation network: A case study in Turkey","authors":"E. Ayyıldız, Gökhan Özçelik, Cevriye Gencer, E. Demirci","doi":"10.35378/gujs.1103774","DOIUrl":"https://doi.org/10.35378/gujs.1103774","url":null,"abstract":"This paper defines a capacitated multiple-source multiple-sink shortest path problem and introduces its extension, called the capacitated multiple-source multiple-sink shortest path network interdiction problem (CMSSNIP). CMSSNIP examines the actions of attackers who attempt to maximize the total shortest path of network users trying to reach the crime locations for the aid process after causing an incident in certain regions to provide strategic information for the defense systems of the government. In this context, the exact mathematical model ensuring useful information about safe routes to network users is proposed. In this manner, to the best knowledge of authors, the CMSSNIP consisting of multiple-source nodes and multiple-sink nodes and considering capacity-demand relations between security units and crime locations is studied for the first time. Accordingly, a set of scenarios is considered based on the interdiction budget levels and the number of crime locations through a real case application to show the applicability of the model. Furthermore, computational experiments are performed to evaluate the model performance on different-sized networks. It is realized that especially the model provides resilient strategies versus interdictions in terms of obtaining the safe shortest paths at the operational level within seconds in the real case application.","PeriodicalId":12615,"journal":{"name":"gazi university journal of science","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45618343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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