Koleksiyon/r/bayburt/10001

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Koleksiyondaki öğeler

  • MakaleAçık Erişim2015Scopus SJRQ2
    Optimum design of composite steel frames with semi-rigid connections and column bases via genetic algorithm

    Artar, Musa; Daloʇlu, Ayşe T.

    A genetic algorithm-based minimum weight design method is presented for steel frames containing composite beams, semi-rigid connections and column bases. Genetic Algorithms carry out optimum steel frames by selecting suitable profile sections from a specified list including 128 W sections taken from American Institute of Steel Construction (AISC). The displacement and stress constraints obeying AISC Allowable Stress Design (ASD) specification and geometric (size) constraints are incorporated in the optimization process. Optimum designs of three different plane frames with semi-rigid beam-to-column and column-to-base plate connections are carried out first without considering concrete slab effects on floor beams in finite element analyses. The same optimization procedures are then repeated for the case of frames with composite beams. A program is coded in MATLAB for all optimization procedures. Results obtained from the examples show the applicability and robustness of the method. Moreover, it is proved that consideration of the contribution of concrete on the behavior of the floor beams enables a lighter and more economical design for steel frames with semi-rigid connections and column bases.

    AtıfScopus26WoS25OpenAlex21
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  • MakaleYalnız künye2014Scopus SJRQ2
    Synthesis and electrochemistry of metallophthalocyanines bearing {4-[(2E)-3-(3,4,5-trimethoxyphenyl)prop-2-enoyl]phenoxy} groups

    Acar, Irfan; Arslan, Tayfun; Topçu, Saim; Aktaş, Ayşe; Şen, Serkan; Serencam, Hüseyin

    In this study, metallophthalocyanines 4, 5, 6 was carried out by the cyclotetramerization of 4-{3-[(2E)-3-(3,4,5-trimethoxyphenyl)prop-2-enoyl] phenoxy}phthalonitrile 3. The synthesis of metallo derivatives [Zn(II), Co(II), Cu(II)] of phthalocyanines obtained from corresponding phthalonitrile derivative and in the presence of the anhydrous divalent metal salts (Zn(CH 3COO)2, CoCl2 and CuCl2) was described. These phthalocyanines showed good solubility in organic solvents such as chloroform, tetrahydrofuran, DMSO and DMF. The newly synthesized Pcs were verified by IR, 1H NMR, 13C NMR, UV-vis and MS spectral data. The electrochemical properties of the zinc(II), copper(II) and cobalt(II) phthalocyanines were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. The cobalt complex showed a metal based reduction process, while zinc phthalocyanines were giving ligand based electron transfer processes.

    AtıfScopus10WoS9OpenAlex12
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  • MakaleAçık Erişim2015Scopus SJRQ2
    Characterization of functional properties of enterococcus faecium strains isolated from human gut

    İspirli, Humeyra; Demirbaş, Fatmanur; Dertli, Enes

    The aim of this work was to characterize the functional properties of Enterococcus faecium strains identified after isolation from human faeces. Of these isolates, strain R13 showed the best resistance to low pH, bile salts, and survival in the simulated in vitro digestion assay, and demonstrated an important level of adhesion to hexadecane as a potential probiotic candidate. Analysis of the antibiotic resistance of E. faecium strains indicated that in general these isolates were sensitive to the tested antibiotics and no strain appeared to be resistant to vancomycin. Examination of the virulence determinants for E. faecium strains demonstrated that all strains contained the virulence genes common in gut-and food-originated enterococci, and strain R13 harboured the lowest number of virulence genes. Additionally, no strain contained the genes related to cytolysin metabolism and showed hemolytic activity. The antimicrobial role of E. faecium strains was tested against several pathogens, in which different levels of inhibitory effects were observed, and strain R13 was inhibitory to all tested pathogens. PCR screening of genes encoding enterocin A and B indicated the presence of these genes in E. faecium strains. Preliminary characterization of bacteriocins revealed that their activity was lost after proteolytic enzyme treatments, but no alteration in antimicrobial activity was observed at different pHs (3.5 to 9.5) and after heat treatments. In conclusion, this study revealed the functional characteristics of E. faecium R13 as a gut isolate, and this strain could be developed as a new probiotic after further tests.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    AtıfScopus41WoS37OpenAlex42
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  • MakaleAçık Erişim2015Scopus SJRQ3
    Measuring attention in second language reading using Eye-tracking: The case of the noticing hypothesis

    Dolgunsöz, Emrah

    Taking Schmidt's (1990) noticing hypothesis as point of departure this study aims to measure attention and learning gains during second language (L2) reading by making use of eye-tracking methodology. Relying on Robinson's hierarchical memory model (1995, 2003), it is hypothesized that vocabulary learning and attention are closely associated. After a vocabulary pre-test, seventy-five learners of English read a standard text individually while their eye movements were being recorded followed by an immediate post-test. The results revealed that learners spent more time on unknown words than they did on familiar ones. Attention and learning gains also positively correlated; fixation values on an unknown word increased its further recognition probability in post-test. Finally, the findings revealed a cut-offpoint of approximately 450ms as an activation threshold for noticing. Eye-tracking as a technique to measure attention in second language acquisition (SLA) was also discussed.

    • SDG 4 · Nitelikli Eğitim
    AtıfScopus15OpenAlex22
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  • MakaleAçık Erişim2018Scopus SJRQ2
    The effect of government educational expendituron labor productivity in turkish manufacturing sector; [Utjecaj vladinih rashoda za obrazovanje na produktivnost rada: Ne-linearni ardl pristup na turski proizvodni sektor]

    Durmaz, Atakan; Pabuçcu, Hakan

    Labor productivity is very important phenomena to maintain the sustainable economic growth. Actually, there are many studies in the economic literature about determining the factors affecting labor productivity. At this point, this study aims to investigate the relationship between labor productivity and government educational expenditure by using the data covering the period of 1971-2015 for Turkey. To this aim, it is applied linear and non-linear autoregressive distributed lag model (ARDL). By using the bound testing approach, the long run relationship between variables has been investigated. Both models have been applied to determine whether the relationship between variables is linear or nonlinear. An asymmetric relationship between labor productivity and government educational expenditure was determined. For this reason, nonlinear model is preferred. The empirical findings indicate that positive changes in educational expenditure has negative effect on labor productivity and negative changes in educational expenditure has positive effect on labor productivity. The long run coefficient of openness is significantly positive; the short run coefficient of it is significantly negative for all lags. On the other hand, the effect of GDP growth on the labor productivity is significantly positive in both short and long run. While the effect of average annual labor worked hours is significantly negative for the first two lags, it is significantly positive the last two lags in short run, it is positive but not significant in long run.

    • SDG 4 · Nitelikli Eğitim
    • SDG 8 · İnsana Yakışır İş ve Ekonomik Büyüme
    AtıfScopus3WoS2OpenAlex3
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  • MakaleAçık Erişim2018Scopus SJRQ3
    Genome sequences of five Lactobacillus sp. isolates from traditional Turkish sourdough

    Dertli, Enes; Skory, Christopher D.; Şimşek, Ömer

    A high level of variation in microflora can be observed in profiles of lactic acid bacteria (LAB) from sourdoughs. Here, we present draft genome sequences of Lactobacillus reuteri E81, L. reuteri LR5A, L. rhamnosus LR2, L. plantarum PFC-311, and the novel Lactobacillus sp. strain PFC-70, isolated from traditional Turkish backslopped wheat sourdoughs.

    • SDG 2 · Açlığa Son
    AtıfScopus8WoS8OpenAlex9
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  • MakaleAçık Erişim2018
    Investigation of the visuals associated with the national identity in Turkish republic revolution history and kemalism textbooks

    Elban, Mehmet

    In this research, images related to national identity were examined in history textbooks. In the first stage, nationalism, the historical course of the Turkish national identity and related literature were examined, and some components of national identity were determined. Various categories related to national identity have been formed from the elements obtained. The data about the categories were collected through document analysis. In the second phase, 8 history textbooks taught in the years 1930-2014 were selected as samples. Content analysis was used in the examination of the mentioned textbooks, and quantitative method was chosen in data analysis. In this context, data obtained by document analysis were analyzed with SPSS 13 statistical program. Chi-square tests, Bonferroni corrections for chi-square tests and graphs were used in the analyzes. The significance level for all analyzes was taken as .05. In the research, it was determined that republic values and revolutions, national struggle and the images related to the founder leader Mustafa Kemal Atatürk be a most used in Turkish Republic Revolution History and Kemalism textbooks concerning national identity. In addition, it has been found that the images of national symbols such as homeland maps, flag, parliament, and capital are used too much for the national identity.

    • SDG 4 · Nitelikli Eğitim
    AtıfScopus4OpenAlex2
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  • MakaleAçık Erişim2014Scopus SJRQ1
    Attractive method for thickness-independent permittivity measurements of solid dielectric materials

    Hasar, Ugur Cem; Barroso, Joaquim José; Bute, Musa; Kaya, Yunus; Kocadagistan, Mustafa Engin; Ertugrul, Mehmet

    We propose a non-resonant-type method for reference-plane invariant and thickness-independent permittivity measurement of solid dielectric materials when there is no information from permittivity. To achieve this, we derive a branch-index-independent function and verify that it determines the sample thickness and permittivity without resorting to finding the correct branch index value for three different measurement scenarios: (a) measurements at closely separated frequencies of non-dispersive samples, (b) measurements at largely separated frequencies of non-dispersive samples, and (c) measurements at largely separated frequencies of dispersive samples. Via a differential uncertainty analysis, the effect of inaccurate sample thickness on permittivity determination is also presented for demonstration of the improvement achieved by our method. For validation, we measured the permittivity of an approximately 20 mm PTFE sample using the presented method and compared its result with those from other similar methods. From the comparison, we note that the accuracy of tested methods from literature drastically decreases when accurate information of sample thickness is not known (in addition to a further decrease in accuracy when correct transformation factors from reference-planes are not known a priori), while the accuracy of our method is not influenced.

    AtıfScopus25WoS22OpenAlex25
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  • MakaleYalnız künye2018Scopus SJRQ3
    Determination of in-vitro antioxidant, anti-urease, anti-hyaluronidase activities by phenolic rich bee products from different region of Turkey

    Can, Zehra

    In this study, enzyme inhibition of urease and hyaluronidase are clinically important functions were examined by different authenticity bee products. Different floral honey, pollen and propolis samples were analyzed in terms of total phenolic compounds (TPC), total flavonoid contents (TFC), ferric reducing antioxidant capacity (FRAP), cupric reducing antioxidant capacity (CUPRAC), and 2,2-diphenyl-1-picryhydrazyl (DPPH) free radical scavenging activities as antioxidant determinants. For the determination of the phenolic composition of the products, RP-UV-HPLC was used. TPC of the honey, pollen and propolis samples were ranged from 17 to 95 and 770 to 989 mg of gallic acid (GAE)/100g, 135-258 mg of GAE/g, and TFC was 1 to 10 mgQE/100g, and 78 to 99 mgQE/100 g, and 9 to 10 mg of QE/g, respectively. Among the bee products, propolis samples were showed the highest phenolic componds, that contained different quantity of protocatequic acid, catechin, caffeic acid, p-coumaric acid, p-hydroxybenzoic acid, ferulic acid and rutin. The urease inhibition vales (IC50) were changed from 7.02 to 33.25 mg/mL, 5.00 to 8.78 and 0.16 to 1.98 mg/mL in the honey, pollen and propolis samples, respectively. The hyaluronidase inhibition values (IC50) were changed from 0.02 to 0.46 g/mL, 0.02 to 0.26 g/mL and 3.26 to 9.21 μg/mL in the honey, pollen and propolis samples, respectively. Honey, pollen and propolis have a significant inhibition on the enzymes, the inhibition may be due to secondary metabolites of phenolic compounds and the mechanism of the inhibition should be studied in detailed.

    AtıfScopus8
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  • MakaleAçık Erişim2015Scopus SJRQ2
    Experimental study to remediate acid fuchsin dye using laccase-modified zeolite from aqueous solutions

    Kalkan, Ekrem; Nadaroglu, Hayrunnisa; Celebi, Neslihan; Celik, Hulya; Tasgin, Esen

    This paper studies, the removal of acid fuchsin dye from aqueous solutions using zeolite natural material after its modification with laccase from Russulaceae (Lactarius volemus). Batch adsorption experiments were performed as a function of pH, contact time, temperature, and adsorbent dosage. The optimum results were obtained at pH 5, contact time of 60 min, temperature of 60ºC, and an adsorbent dosage of 1.5 mg/mL. The isotherm studies show that the adsorption experimental data are fitted well by Langmuir isotherm model. The adsorption capacity found is 31 mg/g. The kinetics of AFD adsorption on LMZ is best described with the pseudo-first-order kinetics model. Thermodynamic parameters including Gibbs free energy, enthalpy, and entropy changes indicate that the adsorption of Acid Fuchsin dye onto laccase-modified zeolite is feasible, spontaneous, and exothermic. The results show that laccase-modified zeolite can be used as an alternative lowcost adsorbent for dye removal from aqueous solutions.

    • SDG 6 · Temiz Su ve Sanitasyon
    • SDG 12 · Sorumlu Üretim ve Tüketim
    AtıfScopus33WoS27OpenAlex29
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  • MakaleYalnız künye2017Scopus SJRQ2
    Highly Enantioselective Production of Chiral Secondary Alcohols Using Lactobacillus paracasei BD101 as a New Whole Cell Biocatalyst and Evaluation of Their Antimicrobial Effects

    Yılmaz, Durmuşhan; Şahin, Engin; Dertli, Enes

    Chiral secondary alcohols are valuable intermediates for many important enantiopure pharmaceuticals and biologically active molecules. In this work, we studied asymmetric reduction of aromatic ketones to produce the corresponding chiral secondary alcohols using lactic acid bacteria (LAB) as new biocatalysts. Seven LAB strains were screened for their ability to reduce acetophenones to their corresponding alcohols. Among these strains, Lactobacillus paracasei BD101 was found to be the most successful at reducing the ketones to the corresponding alcohols. The reaction conditions were further systematically optimized for this strain and high enantioselectivity (99%) and very good yields were obtained. These secondary alcohols were further tested for their antimicrobial activities against important pathogens and significant levels of antimicrobial activities were observed although these activities were altered depending on the secondary alcohols as well as their enantiomeric properties. The current methodology demonstrates a promising and alternative green approach for the synthesis of chiral secondary alcohols of biological importance in a cheap, mild, and environmentally useful process.

    AtıfScopus41WoS35OpenAlex38
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  • MakaleYalnız künye2017Scopus SJRQ2
    Investigation on the physical properties of C-doped ZnO thin films deposited by the thermionic vacuum arc

    Mohammadigharehbagh, Reza; Özen, Soner; Hakan Yudar, H.; Şenay, Volkan; Pat, Suat; Korkmaz, Şadan

    The aim of this study is to determine some physical properties of C-doped ZnO coated on a glass substrate by using the thermionic vacuum arc method. The produced C-doped ZnO thin film is characterized by using several analysis techniques. The produced thin film has a cubic crystal structure, high transmittance in the visible region, symmetrical surface distribution, and optical band gap energy of 3.34 eV. According to the XRD analysis of the produced thin film, it is a fullerene (C60)-doped polycrystalline ZnO. Hardness value and Young's modulus value were determined as 8 GPa and 140 GPa, respectively. These physical properties are adequate for future transparent electrode applications.

    AtıfScopus15WoS15OpenAlex16
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  • MakaleAçık Erişim2018Scopus SJRQ3
    Effect of long-term natural aging on microstructure and room temperature superplastic behavior of UFG/FG Zn-Al alloys processed by ECAP

    Demirtas, M.; Yanar, H.; Purcek, G.

    Two potential superplastic compositions of Zn-Al alloy systems, Zn-22Al and Zn-0.3Al alloys, were chosen and processed by equal-channel angular pressing/extrusion (ECAP/E) in order to achieve high strain rate (HSR) superplasticity at room temperature (RT). ECAP-processed samples of both alloys were then subjected to long-term natural aging up to 1100 days to evaluate the effect of long-term natural aging on their microstructures and superplastic behaviors. Before natural aging, the maximum elongations to failure at RT were 400% for ultrafine-grained (UFG) Zn-22Al at the strain rate of 5 × 10 −2 s −1 and 1000% for fine-grained (FG) Zn-0.3Al at the strain rate of 1 × 10 −4 s −1 . Long-term natural aging did not cause a significant change in the elongation of UFG Zn-22Al alloy with 355% maximum elongation. However, optimum strain rate giving the maximum elongation decreased to 3 × 10 −3 s −1 . On the other hand, Zn-0.3Al alloy lost more than half of its superplastic elongation and showed an elongation to failure of 435% at the end of the natural aging period of 1100 days. Microstructural analyses show that grain boundary corrosion occurred in dilute Zn-0.3Al alloy during the natural aging process. Corroded grain boundaries resulted in cavity nucleation during the tensile tests and some of these cavities attained large sizes and caused premature failure.

    AtıfScopus4WoS4OpenAlex4
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  • MakaleAçık Erişim2014Scopus SJRQ3
    Antioxidant enzyme inhibitor role of phosphine metal complexes in lung and leukemia cell lines

    Saygideʇer Demir, Burcu; Keleş, Tuʇba; Serindaʇ, Osman

    Phosphine metal complexes have been recently evaluated in the field of cancer therapy. In this research, the cytotoxic effects of some metal phosphines { [PdCl2((CH2OH)CH2)CH3] (C1), [RuCl2(((CH2OH)CH2)CH3) (C2), [PtCl2((Ph2PCH2)CH3)(timin) (C3) } on K562 (human myelogenous leukemia cell line) and A549 (adenocarcinomic human alveolar basal epithelial cells) cells were investigated using the MTT test. C1 and C2 are water-soluble metal complexes, which may have some advantages in in vitro and in vivo studies. The effects of the above-mentioned metal complexes on thioredoxin reductase (TrxR) (EC: 1.8.1.9), glutathione peroxidase (GPx) (EC: 1.11.1.9), and catalase (Cat) (EC: 1.11.1.6) enzymes were also tested. The results of this research showed that all three metal complexes indicated dose-dependent cytotoxicity on A549 and K562 cell lines and that the complexes inhibited different percentages of the TrxR, GPx, and Cat enzymes of these tumor cells.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    AtıfScopus7WoS6OpenAlex9
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  • MakaleYalnız künye2017Scopus SJRQ4
    Some physicochemical properties of wild and cultivated pomegranates (Punica granatum L.)

    Gozlekci, S.; Ercisli, S.; Choudhary, R.; Cakir, O.; Sagbas, H.I.

    The fruits of seven wild grown pomegranate genotypes and well-known cultivar Hicaznar were analysed for several physical (fruit mass, shape index, calyx length, peel yield, peel thickness, aril yield and juice yield) and chemical (soluble solid content, titratable acidity, pH, soluble solid content/acidity, total phenolic content, antioxidant activity and total anthocyanin) properties. There were statistical differences within wild genotypes and also between wild genotypes and cv. Hicaznar in terms of most of the parameters. The average fruit mass ranged from 127-192 g among wild genotypes and cv. Hicaznar had 394 g fruit mass. The wild genotypes, in general, had lower aril and juice yields than cv. Hicaznar. However they have higher total phenolic content and antioxidant activity than cv. Hicaznar.

    AtıfScopus1
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  • MakaleYalnız künye2015Scopus SJRQ1
    Spectral features, electric properties, NBO analysis and reactivity descriptors of 2-(2-Benzothiazolylthio)-Ethanol: Combined experimental and DFT studies

    Srivastava, Ruchi; Sinha, L.; Karabacak, M.; Prasad, O.; Pathak, S.K.; Asiri, A.M.; Cinar, M.

    (Chemical Equation Presented). Quantum chemical calculations of ground state energy, geometrical structure and vibrational wavenumbers, nuclear magnetic behaviors, electronic absorption spectra along with the nonlinear optical properties of 2-(2-benzothiazolylthio)-ethanol (BTZTE) were carried out using density functional (DFT/B3LYP) method with 6-311++G(d,p) as basis set. The FT-IR and FT-Raman spectra were measuredinthe condensed state. The fundamental vibrational wavenumbers as well as their intensities were calculated, and a good correlation between experimental and scaled calculated wavenumbers was accomplished. The electric dipole moment, polarizability and the first hyperpolarizability values of the BTZTE were calculated at the same level of theory and basis set. The results show that the BTZTE molecule possesses nonlinear optical (NLO) behavior with non-zero values. Stability of the molecule arising from hyper-conjugative interactions and charge delocalization was analyzed using natural bond orbital (NBO) analysis. UV spectrum of the studied molecule was recorded in the region 200-500 nm and the electronic properties were predicted by time-dependent DFT approach. The calculated transition energies are in good concurrency with the experimental data. 1H nuclear magnetic resonance (NMR) chemical shifts of the title molecule were calculated by the gauge independent atomic orbital (GIAO) method and compared with experimental results. The thermodynamic properties of the studied compound at different temperatures were calculated. Global and local reactivity descriptors were computed to predict reactivity and reactive sites on the molecule.

    AtıfScopus23WoS28OpenAlex28
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  • MakaleAçık Erişim2018Scopus SJRQ1
    Self-Calibrating Noniterative Complex Permittivity Extraction of Thin Dielectric Samples

    Hasar, Ugur Cem; Kaya, Yunus

    A microwave method relying on uncalibrated scattering (S-) parameters is proposed to measure the complex permittivity (ϵr) of thin dielectric samples. It has the following two main advantages. First, it takes into account effect of the sample holder, used for holding the sample, especially important for thin sample electromagnetic property characterization. Second, it does not require any specific information about the location of the sample (and its holder) inside its measurement cell for ϵr extraction. For validation of our method, we applied a commercial three-dimensional electromagnetic simulation program-CST Microwave Studio-and the Lorentz dispersion model. Uncalibrated (as well as calibrated) S-parameter measurements were conducted to measure ϵr of a 0.7 mm thick polyethylene sample (the sample holder was a 5.18 mm thick PVC sample) by our method and other similar methods in the literature. From the comparison, we observed that while the accuracy of tested methods significantly changed with inaccurate knowledge of the sample position inside its cell, the accuracy of our method did not much alter.

    AtıfScopus18WoS16OpenAlex18
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  • MakaleAçık Erişim2015Scopus SJRQ3
    Experimental and numerical investigation of a novel energy-efficient vacuum glazing technology for low-carbon buildings

    Cuce, Erdem

    In this study, a recently developed innovative window technology called vacuum tube window is introduced, and its performance assessment is presented through an experimental and numerical research. The novel design of vacuum tube window consists of evacuated tubes surrounded by Argon as inert gas to eliminate conductive and convective effects inside the window and thus to produce a building element with remarkably low overall heat transfer coefficient (U-value). Heat transfer inside the window was modelled via a reliable commercial computational fluid dynamics software ANSYS FLUENT. The accuracy of simulations was verified by environmental chamber tests. For the vacuum tube diameter of 28 mm, an excellent agreement between experimental and numerical data was achieved. For different values of design parameters such as pane thickness, tube thickness, tube diameter and Argon gap, total heat loss and U-value of the vacuum tube window and optimum data were evaluated. Optimum tube diameter was found to be 60 mm in terms of thermal performance characteristics, cost, lightness and aesthetic issues. It is concluded that the vacuum tube window is able to provide a U-value lower than 0.40 W/m2K, which is very promising for both retrofitting of existing buildings and new-build applications.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    • SDG 11 · Sürdürülebilir Şehirler ve Topluluklar
    • SDG 13 · İklim Eylemi
    AtıfScopus16WoS11OpenAlex18
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  • MakaleYalnız künye2014Scopus SJRQ2
    Effects of initial cooling conditions and measurement heights on the levitation performance of bulk MgB2 superconductor at different measurement temperatures

    Erdem, O.; Ozturk, K.; Guner, S.B.; Celik, S.; Yanmaz, E.

    The levitation properties of MgB2 prepared by hot press at 200 ° C and then pellet/closed tube method has been investigated. The vertical and lateral levitation forces (Fz and Fx) on a cylindrical NdFeB permanent magnet (PM) below a disk-shaped bulk MgB2 were measured during the vertical and lateral traverses of the PM in different cooling heights (CHs) and measurement heights (MHs) at temperatures of 20, 25 and 30 K to investigate the effect of the initial CH and MH on the levitation performance of MgB2. For temperatures below 30 K, it was observed that Fz increases with increasing CH. However, a minute variation in Fz and a big hysteresis loop are observed at 30 K. From the lateral traverses, it was obtained that the Fz with attractive character increases with decreasing MH and the hysteresis effect increases for small MHs due to the increment of the magnetic field intensity which the sample feels with decreasing MH. In addition, it was seen that the character of Fx varies depending on both MH and measurement temperature. The higher hysteresis obtained in Fx than in Fz during lateral traverses implies that the motion of the flux lines in MgB2 is especially in lateral rather than vertical direction. Finally in this study, it was shown that the levitation performance of MgB2 depends not only on the measurement temperature but also on the CH and MH conditions. These results can be useful for optimizing the levitation performance of MgB2 superconductors for potential applications.

    AtıfScopus20WoS21OpenAlex21
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  • MakaleYalnız künye2019Scopus SJRQ3
    Effects of autochthonous Lactobacillus plantarum strains on Listeria monocytogenes in sucuk during ripening

    Kamiloğlu, Aybike; Kaban, Güzin; Kaya, Mükerrem

    The aim of this study was to investigate the effects of autochthonous Lactobacillus plantarum strains (S50, S51, S72, S74, and S85) as starter cultures on growth of Listeria monocytogenes in sucuk (Turkish dry fermented sausage) production. The counts of L. monocytogenes, lactic acid bacteria, and Enterobacteriaceae as well as pH value and moisture content were determined in sucuk during ripening period. L. monocytogenes, lactic acid bacteria, and pH value were significantly affected (p < 0.01) by both starter culture and ripening period. A slight increase in L. monocytogenes count was observed in the control group whereas a reduction was observed in samples produced with L. plantarum strains at the first day of fermentation. Although L. monocytogenes reduction in control group with spontaneous microbiota was 0.54 log cfu/g after 11 days of ripening, reductions of as high as 2.74 log cfu/g was observed in the presence of L. plantarum S50. Practical applications: In the current study, five different autochthonous Lactobacillus plantarum isolates were identified, the effects of these strains on the behavior of Listeria monocytogenes in Turkish fermented sausage (sucuk) were determined. To the best of our knowledge, this is the first report investigating the effects of autochthonous lactic acid bacteria strains on behavior of L. monocytogenes in sucuk fermentation. As starter culture autochthonous lactic acid bacteria can be more competitive than commercial types. Our findings reveal the importance of the use of these autochthonous L. plantarum strains causes rapid pH drop to inhibit L. monocytogenes growth during sucuk fermentation. And also L. plantarum S50 strain may be more suitable for use as bioprotective culture or starter culture compared to other strains.

    AtıfScopus27WoS24
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