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Öğe Synthesis, characterization and antioxidant activity of heterocyclic Schiff bases(Journal of the Chinese Chemical Society, 2020-08-04) Aral, Tarık; Dağ, Beşir; Kızılkaya, Hakan; Genç, Nusret; Erenler, RamazanSchiff base derivatives have gained great importance due to revealing a great number of biological properties. Schiff bases were synthesized by treatment of 4-amino-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (1) with various aldehydes in methanol at reflux. In addition, diamine was reacted with an aldehyde to yield the corresponding Schiff bases. The structures of synthesized Schiff bases were elucidated by spectroscopic methods such as microanalysis, 1 H-NMR, 13C-NMR, and FTIR. Antioxidant activities of synthesized Schiff bases were carried out using different antioxidant assays such as 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH• ) scavenging, 2,20 -azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging, and reducing power activity. (E)-4-((1H-indol-3-yl)methyleneamino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (3), (E)-1,5-dimethyl-4-((2-methyl-1H-indol-3-yl) methyleneamino)-2-phenyl-1H-pyrazol-3(2H)-one (5), (E)-1,5-dimethyl-2-phenyl-4-(thiophen-2-ylmethyleneamino)-1H-pyrazol-3(2H)-one (7), (E)-1,5-dimethyl2-phenyl-4-(quinolin-2-ylmethyleneamino)-1H-pyrazol-3(2H)-one (9), (1S,2S, N1,N2)-N1,N2-bis((1H-indol-3-yl)methylene)cyclohexane-1,2-diamine (11), and (1S,2S,N1,N2)-N1,N2-bis((2-methyl-1H-indol-3-yl)methylene)cyclohexane-1,2-diamine (12) were synthesized in high yields. Compound 5 displayed a good ABTS•+ activity. Compound 3 revealed the outstanding activity in all assays. Compound 7 has the best-reducing power ability in comparison to other synthesized compounds. Although compounds 5, 11, 12 are new, compounds 3, 7, 9 are known. Due to revealing a good antioxidant activity, the synthesized compounds (3, 5, 7) have the potential to be used as synthetic antioxidant agents.Öğe Synthesis and anticorrosion studies of 4-[(2-nitroacetophenonylidene)-amino]-antipyrine on SAE 1012 carbon steel in 15 wt.% HCl solution(Taylor & Francis, 2020-11-16) Gerengi, Hüsnü; Çakmak, Reşit; Dağ, Beşir; Solomon, M. M; Tüysüz Akbal, Hatice Aslıhan; Kaya, ErtuğrulA novel corrosion inhibitor, ((E)-1,5-dimethyl-4-((1-(3-nitrophenyl)ethylidene)amino)-2-phenyl-1,2-dihydro-3H-pyrazol-3-one) (DNPP) was synthesized in high yield by the condensation reaction of 4-aminoantipyrine with 2-nitroacetphenone derived from acetophenone as a starting material and characterized by FT-IR, 1H, and 13C NMR techniques. DNPP was tested against the corrosion of SAE 1012 carbon steel in 15 wt.% HCl solution using electrochemical and surface characterization techniques. Results obtained show that DNPP is effective in retarding the corrosion of SAE 1012 carbon steel. With 4 mM of DNPP, the charge transfer resistance of SAE 1012 in 15 wt.% HCl solution is raised from 17.42 to 140.50 Ω cm2 and the substrate surface is protected by 87%. The inhibition is through adsorption mechanism (mixed-adsorption type) and has been confirmed by SEM and EDAX results. Potentiodynamic polarization results reveal that DNPP acted as a mixed-type corrosion inhibitor. DNPP is a promising candidate for the formulation of an inhibitor cocktail for the strong acid environment.Öğe Optimization and evaluation of dry and minimum quantity lubricating methods on machinability of AISI 4140 using Taguchi design and ANOVA(SAGE Journals, 2020-07-05) Gürbüz, Hüseyin; Gönülaçar, Yunus EmreIn this work, it is aimed to study the effects of dry machining and minimum quantity lubrication application on machinability in turning AISI 4140 steel by utilizing different cutting parameters. Also, this study contains effects and optimization of cutting conditions (dry and minimum quantity lubricating), feed rate, and cutting speed on surface roughness (Ra) and main cutting forces (Fc) determined by employing the Taguchi method. At the end of experiments, it was established that compared to dry machining operations, minimum quantity lubricating significantly reduced cutting tool wear, while Fc and Ra decreased in general. Analyses of variance, regression analysis, signal-to-noise ratio, and orthogonal array were employed to analyze the effects and contributions of independent variables on dependent variables. The optimum levels of the dependent variables for reducing Fc and Ra using signal-to-noise rates were established. According to signal-to-noise ratios, minimum quantity lubricating had a more important effect on Fc and Ra than dry machining. The optimal conditions for Fc and Ra were at 0.16 mm/rev feed rate, 125 m/min cutting speed at minimum quantity lubricating. Analysis of variance results demonstrated that the feed rate is the most influential independent variable on Fc (93.976 %) and Ra (89.352 %). Validation test results exhibited that the Taguchi method and regression analysis were highly achieved methods in the optimization of independent variables for dependent variables. Taguchi optimization technique and regression analysis obtained from Fc (R2Tag. = 0.972 and R2Rag. = 0.997) and Ra (R2Tag. = 0.985 and R2Rag. = 0.996) measurements match really well with the experimental dataÖğe A detailed chemical and biological investigation of twelve allium species from Eastern Anatolia with chemometric studies(Wiley-Blackwell, 2020-11-14) İzol, Ebubekir; Temel, Hamdi; Yılmaz, Mustafa Abdullah; Yener, İsmail; Tokul Ölmez, Özge; Kaplaner, Erhan; Fırat, Mehmet; Haşimi, Nesrin; Öztürk, Mehmet; Ertaş, AbdulselamAllium species are widely consumed as food all over the world. The phenolic profile of ethanol extracts of aerial parts and roots of 12 Allium species, collected from five different Eastern Anatolia regions, were studied using LC-MS/MS. In vitro antioxidant, anticholinesterase, cytotoxic and antimicrobial activities were also tested. The multivariate analyses were performed using principal component and hierarchical cluster analyses. Seventeen of 27 standard compounds were detected in all Allium species. The major components were mainly identified as quinic acid, malic acid, vanillin, and p-coumaric acid. The aerial parts possessed better antioxidant activity than roots. Aerial parts of A. atroviolaceum, A. chrysantherum, A. kharputense, and A. shirnakiense exhibited high cytotoxic activity against DLD-1 colon cancer cell lines (IC50 12.5 μg/mL). A. shatakiense and A. vineale demonstrated good antimicrobial activity against S. aureus and E. coli (MIC 75 μg/mL). According to chemometric analysis, differences were detected between aerial parts and the roots. The aerial parts of A. atroviolaceum, A. chrysantherum, A. kharputense, and A. shirnakiense could be potent in the pharmaceutical industry while A. shatakiense and A. vineale in the food industry after further investigations.Öğe An explicit version of the correspondence between noetherian modules with cartier maps and artinian modules with frobenius maps(Hacettepe University, 2020-10-06) Yeşil, MehmetIn this paper, we introduce an explicit version of the correspondence between Noetherian modules with Cartier maps and Artinian modules with Frobenius maps which recovers the correspondence given by R. Y. Sharp and Y. Yoshino, and the correspondence given by M. Blickle and G. Böckle.Öğe Estimation of surface roughness and cutting speed in CNC WEDM by artificial neural network that employed trainable activation function(SAGE Journals, 2021-02-01) Gürbüz, HüseyinActivation functions are the most significant properties of artificial neural networks (ANN) because these functions are directly related with the ability of ANN in learning or modelling a system or a function. Furthermore, another reason for the significance of the fact that determination of optimal activation function in ANN is its relationship with success level. In this experimental study, the effects of different types of wire electrodes, cooling techniques and workpiece materials on surface roughness (Ra) and cutting speed (Vc) in wire electrical discharge machining (WEDM) were investigated by using trainable activation functions (AFt) and modelling them in ANNs. So far, a number of methods have been performed according to the data set in order to optimally predict Ra and Vc results. Among these methods, randomized ANN with AFt was found to be the best one for robust prediction according to RMSE values. While the value was 0.280 for Vc, it was 0.2104 for Ra. Optimum activation functions in Ra and Vc were found at first and third degree trainable functions, respectively.Öğe Annihilators of Cartier quotients(World Scientific, 2020) Yeşil, MehmetThis paper studies Cartier modules with a computational perspective, and describes an algorithm which produces annihilators of quotients of a given finitely generated Cartier module with a surjective structural map.
