Yazar "Yilmaz, T." seçeneğine göre listele

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    Direct and sulfide mediated treatment of textile effluents in acetate and ethanol-fed upflow sulfidogenic bioreactors
    (Springer, 2023) Yilmaz, T.; Yildiz, M.; Yapici, C. S. Arzum; Annak, H. U.; Ucar, D.
    Sulfate is a key component in the textile industry and sulfate-reducing conditions could enhance dye reduction in the treatment of textile industry wastewater. In this study, a sulfidogenic up flow anaerobic reactors fed with different organic substrates (ethanol and acetate) were operated to treat textile wastewater and Remazol Brilliant Violet 5R was used as a model dyestuff. The reactors were operated for 192 days at 7 operational periods at 1 day HRT. Throughout the study, 2000 mg/L SO42- and 1340-1540 mg/L COD were added to the feed, corresponding to COD/SO42- ratios of 0.67 and 0.77, respectively. Remazol Brilliant Violet 5R was added to feed at a concentration of 50 mg/L on day 148 and its concentration was gradually increased to 1000 mg/L. The maximum dye removal rate was over 990 mg/(L.d) for both reactors. Although high-rate dye removal was achieved, an increase in the dye concentration resulted in a decreased sulfate reduction and COD oxidation for both reactors. In addition to the continuous process, biotic and abiotic batch reactors were operated to identify the dye removal mechanism. Batch reactors showed that biogenic sulfide produced in the sulfate reduction can be used to reduce Remazol Brilliant Violet 5R. Batch reactors also indicated that although abiotic sulfide-based Remazol Brilliant Violet 5R reduction is possible, the presence of microorganisms increased its reduction rate.
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    Effects of drive side pressure angle on gear fatigue crack propagation life for spur gears with symmetric and asymmetric teeth
    (American Society of Mechanical Engineers (ASME), 2019) Karpat, F.; Dogan, O.; Yilmaz, T.; Yüce, Celalettin; Kalay, O.C.; Karpat, E.; Kopmaz, O.
    Today gears are one of the most crucial machine elements in the industry. They are used in every area of the industry. Due to the high performances of the gears, they are also used in aerospace and wind applications. In these areas due to the high torques, unstable conditions, high impact forces, etc. cracks can be seen on the gear surface. During the service life, these cracks can be propagated and gear damages can be seen due to the initial cracks. The aim of this study is to increase the fatigue crack propagation life of the spur gears by using asymmetric tooth profile. Nowadays asymmetric gears have a very important and huge usage area in the industry. In this study, the effects of drive side pressure angle on the fatigue crack propagation life are studied by using the finite element method. The initial starting points of the cracks are defined by static stress analysis. The starting angles of the cracks are defined constant at 45°. The crack propagation analyses are performed in ANSYS SMART Crack-Growth module by using Paris Law. Four different drive side pressure angles (20°-20°, 20°-25°, 20°-30° and 20°-35°) are investigated in this study. As a result of the study the fatigue crack propagation life of the gears is increased dramatically when the drive side pressure angle increase. This results show that the asymmetric tooth profile not only decrease the bending stress but also increase the fatigue crack propagation life strongly. Copyright © 2019 ASME.
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    Increasing biomethane production from paper industry wastewater with optimum trace element supplementation
    (Springer, 2023) Toprak, D.; Yilmaz, T.; Ucar, D.
    Trace elements are important components to increase biomethane production performance. Their reactor-specific required concentrations should be determined for each application. In this study, the effects of trace element addition on biogas and biomethane production in an anaerobic reactor treating paper industry wastewater were investigated. The study was conducted by operating multiple batch reactors and using the Box-Behnken experiment design method. The biogas and biomethane responses (R-2 values) were 0.9506 and 0.9374, respectively, indicating that the Box-Behnken model was significant. While influent COD and VSS were 2594 +/- 180.8 and 2885 +/- 16.45 mg/L, optimum Fe, Cu, Ni, Co, and Mg concentrations were 196.8, 0.01, 1.30, 1.31, and 50.63 mg/L, respectively. For biogas and biomethane production, 11 +/- 0.27% and 18 +/- 0.45% increases were observed in reactors with trace elements added, compared to the control, respectively. Biogas and biomethane production rates were also monitored with 15-day kinetic studies. From day 9 to 15, the reactor with trace elements added became superior to the control group by means of daily biogas and biomethane production. The microbial community of the reactor biomass was investigated with 16S V3-V4 rRNA targeted metagenomic analysis and the dominant species was Methanosaeta thermophila (an acetate utilizing bacteria) with a rate of 38.05%. [GRAPHICS] .