Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Dertli, Enes(17)
- Şahin, Engin(8)
- Bayram, Ozkan(7)
- Esmer, Yusuf(7)
- Degirmenci, Yavuz(6)
- Yilmaz, Mustafa Tahsin(6)
- Dursunoğlu, İsmail(5)
- Göktaş, Bora(5)
- İspirli, Hümeyra(5)
- Şenay, Volkan(5)
- Bulut, Mehmet(4)
- Can, Zehra(4)
- Kaban, Güzin(4)
- Korkmaz, Özge(4)
- Pabuçcu, Hakan(4)
- Sagdic, Osman(4)
- Sefali, Abdurrahman(4)
- Serencam, Hüseyin(4)
- Simsek, Onder(4)
- Taylan, Osman(4)
- Ag, Aliriza(3)
- Bayraktar, Bülent(3)
- Bulut, Ayhan(3)
- Cuce, Erdem(3)
- Dayi, Faruk(3)
- Durmaz, Atakan(3)
- Gökçe, H. Süleyman(3)
- Küçük Demir, Betül(3)
- Mavi, Ahmet(3)
- Ucan, Izzet(3)
- Uçurum, Metin(3)
- Özen, Soner(3)
- Öztürk, Mesut(3)
- Abdioglu, M.(2)
- Acar, Adalet(2)
- Agirman Aydin, Tuba(2)
- Akay, Ebru Çağlayan(2)
- Akkan, Yaşar(2)
- Akkoyunlu, Ebubekir(2)
- Akkuş, Ömer(2)
Yayınlar
- MakaleYalnız künye2019Scopus SJRQ1Optimum design of steel space truss towers under seismic effect using Jaya algorithm
Artar, Musa; Daloğlu, Ayşe T.
This study investigates optimum designs of steel space truss towers under seismic loading by using Jaya optimization algorithm. Turkish Earthquake Code (2007) specifications are applied on optimum designs of steel space truss towers under the seismic loading for different local site classes depending on different soil groups. The proposed novel algorithm does not have any algorithm-specific control parameters and depends only a simple revision equation. Therefore, it provides a practical solution for structural optimization problems. Optimum solutions of the different steel truss examples are carried out by selecting suitable W sections taken from American Institute of Steel Construction (AISC). In order to obtain optimum solutions, a computer program is coded in MATLAB in corporated with SAP2000-OAPI (Open Application Programming Interface). The stress and displacement constraints are applied on the design problems according to AISC-ASD (Allowable Stress Design) specifications. Firstly, a benchmark truss problem is examined to see the efficiency of Jaya optimization algorithm. Then, two different multi-element truss towers previously solved with other methods without seismic loading in literature are designed by the proposed algorithm. The first space tower is a 582-member space truss with the height of 80 m and the second space tower is a 942-member space truss of about 95 m height. The minimum optimum designs obtained with this novel algorithm for the case without seismic loading are lighter than the ones previously attained in the literature studies. The results obtained in the study show that Jaya algorithm is a practical and robust optimization method for structural optimization problems. Moreover, incorporation of the seismic loading causes significant increase in the minimum design weight.
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İncele - MakaleYalnız künye2019Scopus SJRQ1Bleeding characteristics of high consistency heavyweight concrete mixtures
Gökçe, H. Süleyman; Andiç-Çakır, Özge
Bleeding, a type of static segregation derives from density difference of concrete ingredients in fresh state. Due to having this difference higher than normal weight counterparts, heavyweight concrete is more susceptible to bleeding, thus, this type of concrete is commonly produced in low slump values. In order to give a response to advances and demands in concrete technology, heavyweight concrete mixtures with high slump values were designed at various mixture characteristics, and their bleeding characteristics were researched in the study. For this purpose, totally, thirty-five concrete mixtures with ≥150 mm slump values were produced by using common cement replacement materials (silica fume and fly ash), viscosity modifier, and various water/binder ratios at two binder dosages. The mixtures showed excessive bleeding capacities ranged from 0 to 11.7% and bleeding rates ranged from 0 to 5.1 kg/m2/h. Silica fume was found as the most effective admixture for reducing or elimination of the bleeding. Bleeding time generally shorten at high binder content and at high water/binder ratio. It was observed that the bleeding adversely affects the hardened characteristics of heavyweight concrete mixtures.
AtıfScopus62WoS54OpenAlex59İncele - MakaleYalnız künye2019Scopus SJRQ3Production of enantiomerically enriched chiral carbinols using Weissella paramesenteroides as a novel whole cell biocatalyst
Tozlu, Caner; Şahin, Engin; Serencam, Hüseyin; Dertli, Enes
In this study, four bacterial strains were tested for their ability to reduce acetophenones to its corresponding alcohol. Among these strains Weissella paramesenteroides N7 was found to be the most successful biocatalyst to reduce the ketones to the corresponding alcohols. The reaction conditions were systematically optimized for W. paramesenteroides N7 that resulted in high enantioselectivity and conversion rates for the bioreduction. The scale-up asymmetric reduction of 1-(4-methoxyphenyl) propan-1-one (1r) by W. paramesenteroides N7 gave (R)-1-(4-methoxyphenyl) propan-1-ol (2r) with 94% yield and >99% enantiomeric excess. This is the first report showing the synthesis of (R)-1-(4-methoxyphenyl) propan-1-ol (2r) in enantiopure form using a biocatalyst on a gram scale. The whole cell catalyzed the reductions of ketone substrates on the preparative scale, demonstrating that W. paramesenteroides N7 would be a valuable biocatalyst for the preparation of chiral aromatic alcohols of pharmaceutical interest as a promising and alternative green approach.
AtıfScopus12WoS10OpenAlex11İncele - MakaleAçık Erişim2019Scopus SJRQ1An analysis on the relation between the seed distance and vertical levitation force for the multi−seeded YBCO using the modified advanced frozen image (MAFI) and experimental methods
Ozturk, K.; Guner, S.B.; Abdioglu, M.; Demirci, M.; Celik, S.; Cansiz, A.
The higher magnetic levitation force and related stiffness values are very important for Maglev and magnetic bearing applications. Also, larger superconducting surface area is needed for continuous and larger magnetic mediums with different geometries and dimensions in real scale industrial applications of superconducting systems. In this study, the cylindrical YBCO superconductors were fabricated by top−seeded melt growth (TSMG) method in single and two−seeded forms with different seed distances and then the magnetic force and stiffness measurements were carried out by three axes magnetic force measurement system in different cooling heights (CH) of 20 mm and 75 mm. Additionally, a new analytical method, based on the magnetic dipole approximation, is proposed to calculate the levitation force in this study, named as Modified Advanced Frozen Image Method (MAFI), since although the Advanced Frozen Image Method in literature can calculate the levitation force with hysteresis, this method does not include the size effect of the superconductor. In the experimental studies, it is seen that the maximum levitation force values obtained by PMG with three PMs (named PMG−1) are more than two times higher than that of obtained with single PM for all samples with different distance of seeds, because of the higher magnetic flux distribution of related PMG arrangement than the single PM. In addition, the maximum magnetic levitation force value firstly increased and then decreased due to current coupling effect weakness by increasing distance of seeds. The calculated analytical levitation force results are not compatible with the experimental results without current coupling effect, but a well agreement is observed when the current coupling effect is taken into account in calculations. Also the MAFI method was tested with different dimensions of superconductors and the obtained results indicated the success of the proposed method. The maximum levitation force values obtained with MAFI method increased with increasing dimensions of HTS and PMs. Thus, one can say that the MAFI method is useful for the levitation force calculations between multi−seeded superconductors and PMGs with different dimensions and for different CHs. As a result, the analytical levitation force values obtained with the MAFI method are agree with the experimental levitation force sufficiently and this method can give fast calculation results without any divergence problem. This method can be thought as an alternative to the numerical calculation methods, having serious divergence problems for much amount and bigger size superconducting samples, therefore it will be useful to clarify bulk superconducting properties as supporter to the experimental studies.
AtıfScopus19WoS18OpenAlex22İncele - MakaleAçık Erişim2019Scopus SJRQ2Antioxidant Activity, Physiochemical and Sensory Characteristics of Ice Cream Incorporated with Sloe Berry (Prunus spinosa L.)
Ürkek, Bayram; Şengül, Mustafa; Akgül, Halil İbrahim; Kotan, Tuba Erkaya
The aim of this study was to determine the influence of sloe berry (SB) addition at different ratios on the physical, chemical, antioxidant, colour and sensory properties and mineral contents of ice creams. The increment of SB led to the an increase of titratable acidity, overrun, viscosity and ash values, first dripping and complete melting times; in contrast, it decreased the total solid, pH and fat values. Mn and Zn values were affected significantly (P < 0.05) by the addition of SB but other element levels were not affected. L* and b* values decreased significantly in all samples as compared with control sample, while a*, H°, C* and ∆E* increased significantly with addition of SB. Antioxidant activity was the highest in the sample containing 15 % SB (w/w) among ice cream samples. The ice cream samples containing 15 % SB had higher score than the control sample in terms of colour and appearance, gumming structure and general acceptability.
AtıfScopus26WoS22OpenAlex26İncele - MakaleAçık Erişim2019Scopus SJRQ1Non-linear rheological (LAOS) behavior of sourdough-based dough
Yildirim-Mavis, Cigdem; Yilmaz, Mustafa Tahsin; Dertli, Enes; Arici, Muhammet; Ozmen, Duygu
During processing, wheat dough is known to undergo large deformation led by mixing and fermentation processes. This deformation is much more pronounced when sourdough is used in the recipe of wheat dough whose gluten is considerably hydrolyzed during sourdough fermentation. This causes deeper effects on rheological properties and shelf life of bakery products. Traditional small amplitude oscillatory tests do not enable us to comprehend the viscoelasticity under large deformations. In this respect, large amplitude oscillatory shear (LAOS) tests are useful for accurate characterization of the non-linear mechanical response. This study, therefore, is undertaken to investigate the non-linear mechanical response of dough prepared with different amounts of sourdough (0, 10, 20 30 and 40%) in a strain values ranging from 0.005 to 200% (frequency at 10 rad/s). As a result, sourdough was determined to have considerable effects on the non-linear viscoelastic response of dough. Strain-stiffening and shear-thinning behaviors were considerably influenced by sourdough incorporation and the dough started to show strain-softening and lowered shear-thinning behavior after giving a peak around at 100% strain due to the onset of the breakdown of the gluten network and suspension of starch matrix as consequence of the metabolic activity of the starter culture (Lactobacillus brevis E25) used in the preparation of sourdough. The physicochemical (pH and TTA), microbiological properties (LAB count) and extensographic properties were also shown to support the LAOS results. LAOS tests could be effectively and clearly used to reveal the effect of processing conditions (sourdough content and deformation by large strain amplitude) on the non-linear mechanical response of wheat dough.
AtıfScopus49WoS46OpenAlex46İncele - MakaleAçık Erişim2019Scopus SJRQ2Investigation of magnetic force properties between different PMGs and multi-seeded YBCO superconductors with different seed distances
Abdioglu, M.; Ozturk, K.; Guner, S.B.; Celik, S.; Kucukomeroglu, T.
The magnetic levitation force in vertical direction and guidance force in lateral direction should be increased for enhancing the loading capacity and stability of Maglev systems, respectively. In this study, we have produced multi‒seeded YBCO (YBa2Cu3O7) superconductors with two seeds and investigated the effect of seed distance on the vertical levitation force and lateral guidance force properties by using different permanent magnetic guideway (PMG) arrangements. Although there are studies in literature related to different distance, orientation and angle of seeds; there is no detailed study investigating the effect of seed distance on the vertical and lateral magnetic force properties of Maglev systems depending on different types of PMGs. In this study, after the sample fabrication, the optimum PMG arrangement were determined by using numerical simulation to obtain magnetic flux density distribution. It is determined that both maximum levitation and guidance force values firstly increased with increasing the seed distance from 0 to 4 mm and then related forces decreased with increasing the seed distance from 4 to 16 mm but still keep the higher force values than the sample with the seed distances of 0 mm. This situation is clarified as the increasing of the seed distance to an optimum value enhances both the levitation and guidance forces simultaneously and this is very important for levitation force applications because it causes to easy control of the Maglev system in vertical and lateral directions.
AtıfScopus4WoS4OpenAlex5İncele - MakaleAçık Erişim2019Scopus SJRQ2Determination of acceptable quality limit for casting of a356 aluminium alloy: Supplier’s quality index (SQI)
Erzi, Eray; Gürsoy, Özen; Yüksel, Çağlar; Colak, Murat; Dispinar, Derya
Aluminium and its alloys have been widely used in the automotive industry for some time and A356 is one of the most popular aluminium alloys today in the sector. It contains approximately 7 wt.% Si and 0.3 wt.% Mg. Due to the defects that may be present in the cast parts, expected mechanical properties may not be reached and this alloy may perform in service under its potential. In a low pressure die casting, several precautions have to be taken in order to produce high quality and defect-free castings. Temperature of casting and the schemical composition of the melt is recorded continuously. Die temperature, pressure levels and their durations are optimized; degassing and fluxing operations are performed. Yet, regardless of the precautions, there could still be rejected parts. It is becoming clear that a good quality raw material is one of the most underrated points of the industry and that the starting material has a great effect on the final product and it should be taken in to account more seriously. Therefore, regarding the first rule of Campbell’s 10 Rules of Casting, in this study, the quality of the starting material of supply chains for a wheel manufacturer was investigated. Chemical compositions were compared, fluidity tests, mechanical tests and bifilm indexes of these various sources and ingots were measured and a final quality index was proposed to create a reference for the quantification of quality of supplier’s ingots. This new index was compared with the rejection rates.
AtıfScopus40WoS33OpenAlex39İncele - MakaleAçık Erişim2019Scopus SJRQ3Infinitely many solutions for the stationary fractional p -Kirchhoff problems in RN
Akkoyunlu, Ebubekir; Ayazoglu, Rabil
In the present paper, we investigate the existence of multiple solutions for the nonhomogeneous fractional p-Kirchhoff equation M(∬R2N|u(x)-u(y)|p|x-y|N+psdxdy+∫RNV(x)|u|pdx)×((-Δ)psu+V(x)|u|p-2u)=f(x,u)inRN,where (-Δ)ps is the fractional p-Laplacian operator, 0 < s< 1 < p< ∞ with sp< N, M:R0+→R0+ is a nonnegative, continuous and increasing Kirchhoff function, the nonlinearity f: RN× R→ R is a Carathéodory function that obeys some conditions which will be stated later and V∈ C(RN, R+) is a non-negative potential function. We first establish the Bartsch–Pankov–Wang type compact embedding theorem for the fractional Sobolev spaces. Then multiplicity results are obtained by using the variational method, (S+) mapping theory and Krasnoselskii’s genus theory.
AtıfScopus4WoS4İncele - MakaleAçık Erişim2019Scopus SJRQ1Active vibration control of a blade element with uncertainty modeling in PZT actuator force
Sivrioglu, Selim; Bolat, Fevzi Cakmak; Erturk, Ercan
The aim of this research is to attenuate the vibrations of a blade structure with an attached piezoelectric actuator using robust multi-objective control. The force obtained from a piezoelectric patch loading has uncertainties due to the complicated shape (airfoil) of the blade element. A parameter-dependent model of the force equation is developed to understand the possible variation range of the actuation force. The modal analysis of the blade is performed to find vibration mode frequencies, and an aerodynamic load is generated experimentally to create steady-state vibration on the blade. A state-space model is obtained by considering certain vibration modes and the parameter-dependent part of the force in the input vector is taken outside of the plant model. The robust stability filter is modified with parameter dependency to have a cluster of the filter. Two different multi-objective controllers are designed with different design objectives. The designed controllers are implemented in experiments and performances of the controllers are compared using frequency and time domain responses. It is shown that the flexible blade vibrations are successfully suppressed with the proposed mixed norm robust controllers under the effect of steady-state aerodynamic disturbance with different air speeds. It is observed in experimental results that the performances of the H∞/H2 controller are better than the H2/H∞ controller.
AtıfScopus22WoS20OpenAlex20İncele - MakaleYalnız künye2019Scopus SJRQ2The relationship between the external magnetic field and K X-ray intensity ratios of immiscible MoxAg1-x alloys
Uğurlu, Mine; Alım, Bünyamin; Demir, Lütfü
Kβ/Kα intensity ratios were obtained for Molybdenum-Silver alloys produced in different concentration range in different magnetic fields. It was seen that these values without magnetic field were found slight different from each other for pure Mo, pure Ag, alloyed Mo and alloyed Ag. It was determined that Kβ/Kα intensity ratios change slightly by depending on alloying element composition and it was seen that Kβ/Kα intensity ratios of Mo and Ag are in the range of the literature valuesFurthermore, that these values have same direction with the changing of the magnetic field for all alloying composition may take us conclusion which alloys in different concentration may have same magnetic properties.
AtıfScopus3WoS2OpenAlex4İncele - MakaleYalnız künye2019Scopus SJRQ1Dynamic analyses of experimentally-updated FE model of historical masonry clock towers using site-specific seismic characteristics and scaling parameters according to the 2018 Turkey building earthquake code
Genç, Ali Fuat; Ergün, Mustafa; Günaydin, M.; Altunişik, Ahmet Can; Ateş, Şevket; Okur, Fatih Yesevi; Mosallam, Ayman S.
This paper presents a dynamic analysis considering site-specific seismic characteristics for a masonry clock tower located at the city of Çorum, Turkey according to the new Turkish earthquake code. Finite element model of the tower was modeled using ANSYS software in order to determine numerical dynamic characteristics of the structure such as natural frequencies and mode shapes. Non-destructive experimental measurements were performed to extract the experimental dynamic characteristics. Experimental results were used as a reference parameter for finite element model updating to reflect the current structural behavior of clock tower. Model updating procedure was carried out by changing of initial material properties of structural stone elements, and maximum differences were reduced from 23.44% to 4.90%. Numerical results indicated that displacements have an increasing trend with the height of the clock tower. Furthermore, the maximum displacements occurred at the top point between the values of 18.88 mm to 42.5 mm. Numerical results also showed that both the maximum and minimum principal stresses occurred at the upper body (clock zone) walls and transition segment between the values of 1.08 MPa/2.86 MPa and − 0.87 MPa/−3.00 MPa, respectively. The maximum and minimum principal strains occurred at the upper body (clock zone) walls between the values of 0.65E-3/1.56E-3 and − 0.78E-3/−1.50E-3, respectively. It is also concluded that non-destructive experimental measurement is very useful method to evaluate in-situ structural identification, validate and update the initial finite element model for further analyses.
AtıfScopus46WoS43OpenAlex51İncele - MakaleYalnız künye2019Scopus SJRQ1A novel perspective for Lactobacillus reuteri: Nanoencapsulation to obtain functional fish fillets
Ceylan, Z.; Uslu, Emin; İspirli, Hümeyra; Meral, Raciye; Gavgalı, Mehmet; 'Yilmaz, Mustafa Tahsin; Dertli, Enes
Enrichment of food products with beneficial Lactic Acid Bacteria (LAB) is an important methodology used to develop functional food products. Lactobacillus reuteri E81 was successfully nanoencapsulated into poly (vinyl alcohol)-based nanofibers for its application to the surface of fish fillets. The Scanning Electron Microscopy analysis confirmed the nanoencapsulation of L. reuteri E81 in electrospun nanofibers (LRNF) that had an average diameter of 381.83 ± 130.69 nm. LAB growth in rainbow trout fillets and fatty fish (mackerel) and were found to be 2.92 and in the range of 3.27 and 2.66 log CFU/g, respectively. Importantly, the antioxidative characteristics of fish fillets significantly increased following their coating with LRNF. The results revealed a significant increase in the inhibition of free radicals in the samples treated with nanoencapsulated L. reuteri as compared to control group fish fillet samples. DPPH activity significantly increased to 40.24%, 44.96%, 44.97 in mackerel samples treated with nanoencapsulated L. reuteri (MLR) and increased to 19.76%, 20.87%, 21.46% in rainbow samples treated with nanoencapsulated L. reuteri (RLR). MLR samples exhibited the highest ABTS radical-scavenging activity (1631 μmol TEAC/g). FRAP value of MLR samples was found to be 1.70 times higher than the control group samples.
AtıfScopus50WoS37OpenAlex45İncele - MakaleYalnız künye2019Scopus SJRQ1A study on 3D graphene synthesized directly on Glass/FTO substrates: Its Raman mapping and optical properties
Bayram, Ozkan
In this study, vertically oriented (3D) graphene nanostructures (VGN) were obtained on Glass and Fluorine doped tin oxide (FTO) substrates at relatively low temperatures (approaximatelly at 400 °C) by using plasma enhanced chemical vapor deposition (PECVD) technique. VGNs were characterized using Raman, Uv–Vis and SEM spectroscopies, respectively. Raman spectroscopy showed that growth temperature significantly affected VGN formation and film quality. The layer structures of these VGNs were also confirmed by Raman mapping. The most important data obtained from this study is that although the applied radio frequency (RF) power is the same, the growth temperature significantly affects the graphene formation and morphologies. This was attributed to the fact that CH4 decomposition was very difficult at low temperatures. The optical transmittance of VGNs ranged from 50% to 95% (at 550 nm wavelength) and their electrical conductivity was also determined to be between 5.94 kohm/sqr and 11.2 kohm/sqr. The electrical and optical properties of VGNs, which have a large surface area, indicated that they may be an alternative material for sensor, solar cell and supercapacitor applications.
AtıfScopus19WoS18OpenAlex20İncele - MakaleAçık Erişim2019Scopus SJRQ1Inhibition of growth of U87MG human glioblastoma cells by Usnea longissima Ach.
Emsen, Bugrahan; Ozdemir, Ozlem; Engin, Tubanur; Togar, Basak; Cavusoglu, Seyda; Turkez, Hasan
Herbal medicines are efficient to reduce side effects in the fight against glioblastoma, which plays a critical role within brain cancer species. The recent studies designated for testing the effects of lichens that have shown numerous anticancer activities on glioblastoma so far. In the present study, different concentrations of water extract obtained from Usnea longissima Ach. were used in order to determine cytotoxic (via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase tests), antioxidant (via total antioxidant capacity test), pro-oxidant (via total oxidant status test) and genotoxic (via 8-hydroxy-2'-deoxyguanosine test) effects of them on human U87MG-glioblastoma cancer cell lines. Primary mixed glial-neuronal non-cancerous cells from Sprague-Dawley rats were also utilized to measure the effects of treatments on non-cancerous cells. Based on median inhibitory concentration values, the data belonged to non-cancerous cells (2486.71 mg/L) showed distinct towering compared to U87MG (80.93 mg/L) cells. The viability of non-cancerous and U87MG cells exposed to extract is decreased in a dose dependent manner. It was also showed that low concentrations of extract notably increased total antioxidant capacity on non-cancerous cells. In addition, various phenolic compounds in extract were detected through high-perfonnance liquid chromatography. The recent results encourage that extract will be able to have therapeutic potential against glioblastoma.
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