Person: GENÇ, SEVAL
Loading...
Email Address
Birth Date
Research Projects
Organizational Units
Job Title
Last Name
GENÇ
First Name
SEVAL
Name
9 results
Search Results
Now showing 1 - 9 of 9
Publication Metadata only Rheological characteristics of exopolysaccharides (EPSs) produced by Brevibacillus thermoruber(ELSEVIER SCIENCE BV, 2012) TOKSOY ÖNER, EBRU; Yildiz, Songul Yasar; Ozer, Tugba; Radchenkova, Nadia; Genc, Seval; Oner, Ebru Toksoy; Kambourova, MargaritaPublication Metadata only Adsorptive removal of bisphenol A from aqueous solutions using phosphonated levan(ELSEVIER, 2019) HACIOSMANOĞLU, GÜL GÜLENAY; Haciosmanoglu, Gul Gulenay; Dogruel, Tugce; Genc, Seval; Oner, Ebru Toksoy; Can, Zehra SemraIn this study, the potential use of phosphonated Halomonas Levan (PhHL) as a natural and cost effective adsorbent for Bisphenol A (BPA), was systematically investigated via the study of the adsorption equilibrium, kinetics, and reuse potential as well as the interpretation of adsorption mechanism. The effects of pH and temperature on the adsorption were also evaluated. The maximum amount of BPA adsorbed on the unit weight of PhHL was determined as 104.8 (-/+ 5.02) mg/g (at 298 K) and the maximum adsorption capacity was calculated as 126.6 mg/g by Sips model. FTIR and XPS studies were conducted to elucidate the adsorption mechanism. Based on the obtained results OH-pi and CH-pi interactions were found to be effective in the adsorption mechanism. The reuse ability was studied with three cycles of adsorption-desorption, and the results showed that the BPA adsorbed per gram of the PhHL decreased 28.6% after the third cycle. This study has shown that PhHL can be used as an effective adsorbent for the removal of BPA from aqueous solutions. The obtained results may be useful in the development of PhHL based adsorption systems for the removal of EDCs with similar chemical properties to BPA.Publication Metadata only Mechanical and electrical properties of Bi1.5-xLaxZn0.92Nb1.5O6.92 pyrochlore ceramics(SPRINGER, 2016) GENÇ, SEVAL; Qasrawi, A. F.; Kmail, Renal R. N.; Mergen, A.; Genc, SevalThe physical properties of Bi1.5-xLaxZn0.92Nb1.5O6.92 solid solutions are investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersion X-ray spectroscopy (EDS), and temperature dependent relative permittivity and electrical resistivity measurements. The La content which was varied from 0.10 to 0.60 is found to be solvable up to 0.21. Further increase in the amount of the La content caused the appearance of Bi0.4La0.6O1.5, LaNbO4, and ZnO minor phases in the pyrochlore matrix. While the lattice parameter and the theoretical, bulk and relative density are hardly affected by the increase in the La content, the strain, the dislocation density and the crystallite size are remarkably varied. The relative permittivity and temperature coefficient of relative permittivity are found to be sensitive to the La-Content. The electrical resistivity is observed to be temperature invariant below 390 K. It exhibits an insulator-semiconductor transition property at a critical temperature that increases with the increasing La content. Such observation is assigned to the increase in the dislocation density, which arises from the increment in the La content. The activation energies of the doped ceramics, which are determined from the electrical resistivity analysis are found to be similar to 1.12-1.00 eV.Publication Metadata only Halomonas smyrnensis as a cell factory for co-production of PHB and levan(ELSEVIER SCIENCE BV, 2018) KASAVİ, CEYDA; Tohme, Souha; Haciosmanoglu, Gul Gulenay; Eroglu, Mehmet Sayip; Kasavi, Ceyda; Genc, Seval; Can, Zehra Semra; Oner, Ebru ToksoyLevan is a fructan type polysaccharide that has long been considered as an industrially important biopolymer however its limited availability is mainly due to the bottlenecks associated with its large-scale production. To overcome such bottlenecks in the commercialization of this very promising polysaccharide, co-production of levan with polyhydroxyalkanoates (PHAs) by halophilic Halomonas smyrnensis cultures has been proposed in this study for the first time. After in silico and in vitro assessment of PHA accumulation, fermentation profiles for levan and PHA concentrations were obtained in the presence of sucrose and glucose and the PHA granules observed by TEM were found to be poly(3-hydroxybutyrate) (PHB) after detailed structural characterization by GC-MS, DSC, FTIR and NMR. Six nutrient limitation strategies based on nitrogen (N) and phosphorus (P) were tested but highest levan and PHB yields were obtained under unlimited conditions. H. smyrnensis is proved to co-produce PHB and levan while using inexpensive carbon sources which is a commercially successful microbial cell factory system showing a great potential in lowering manufacturing costs and aiming for a zero waste policy within the biorefinery concept. (C) 2018 Elsevier B.V. All rights reserved.Publication Metadata only Experimental study on heat transfer of the magnetorheological fluids(IOP PUBLISHING LTD, 2013) GENÇ, SEVAL; Yildirim, Gokhan; Genc, SevalThermal conductivity of magnetorheological suspensions synthesized with iron powder and silicone oil is experimentally investigated for varying particle volume fractions (5, 20, and 40 vol%) of two different grades of iron (Fe) and magnetic field strengths. In order to determine the temperature range at which the thermal conductivity of MR fluids is more effective for different heat transfer applications, the experiments are done for three different temperature intervals in three different temperature ranges: from -20 to 0 degrees C, from 0 to 50 degrees C, and from 50 to 100 degrees C. In this study, ISO 8301 'Thermal insulation-determination of steady state thermal resistance and related properties-heat flow meter apparatus' is used. The thermal conductivity of the MR fluids shows an increase with increasing magnetic field and volume fraction in the temperature intervals from 0 to 50 degrees C and from 50 to 100 degrees C. In particular, there is a substantial enhancement in the thermal conductivity for the 50-100 degrees C temperature interval (enhancement ratio by almost 134% for 40SM at H = 150 G). However, the thermal conductivity shows a decrease in the lower temperature interval from 20 to 0 degrees C (a decrease by 42% for 40SM at 150 G), which could be due the effect of the thermal conductivity of silicone oil at lower temperatures. Although the heat transfer coefficient is higher for higher particle concentrations, the percentage increase is more pronounced for lower particle concentrations, especially in the 0 to 50 degrees C temperature interval (for the 40SM sample at 150 G 18% an enhancement for a 20 K temperature difference is observed, whereas for the 20% MR fluid sample, the enhancement is 34%).Publication Metadata only Synthesis and rheology of ferrofluids: a review(ELSEVIER SCI LTD, 2014) GENÇ, SEVAL; Genc, Seval; Derin, BoraThere is no doubt about the potential technological significance of ferrofluids. The promising applications have been identified as dynamic sealing, heat dissipation, damping, and doping of technological materials. Ferrofluids are known as magnetic liquids that are colloidal suspensions of ultrafine, single domain magnetic particles in either aqueous or non-aqueous liquids. In this review article a general classification and the main properties of ferrofluids, description of their synthesis in terms of stability and rheology, and how it is understood in various parts of the science and technology are given. Then the structural changes and rheological properties of these smart fluids under an external stimulus together with a series of applications are presented.Publication Open Access Manyetoreolojik (MR) Akışkanların Kapalı Durum Viskozitesinin İncelenmesi(2019-09-30) GENÇ, SEVAL; SEVAL GENÇBu çalışmada silikon yağ ve demir (Fe) bazlı manyetoreolojik (MR) akışkanlarının kapalı durum (off-state) viskozite özellikleri incelenmiştir.Farklı oranlardaki manyetik faz miktarı (hacmen %5, 10, 20, 30 ve 40) ile hazırlanan MR akışkanlarının rölatif viskozitesinin (ηrel)– manyetik faz miktarına (φ) olan ilişkisi deneysel olarak tespit edilmiştir. Elde edilen veriler Mooney ve Krieger-Dougherty modelleriylekarşılaştırılmıştır. Deneysel sonuçlar MR akışkanın viskozitesinin manyetik faz miktarı ile önemli ölçüde arttığını göstermiştir. Ayrıca viskoziteprofilleri Mooney modeli ile uyumlu bulunmuştur.Publication Metadata only Bright white up-conversion emission from sol-gel derived Yb3+/Er3+/Tm3+: Y2SiO5 nanocrystalline powders(ELSEVIER SCI LTD, 2015) EKMEKÇİ, METE KAAN; Erdem, Murat; Erguzel, Olgun; Ekmekci, Mete K.; Orucu, Humeyra; Cinkaya, Hatun; Genc, Seval; Mergen, Ayhan; Eryurek, Gonul; Di Bartolo, BaldassareBright white up conversion emission has been observed in sol gel derived Yb3+/Er3+/Tm3+: Y2SiO5 nanocrystalline powders when excited with the 950 nm emission of a laser diode. Measurements of the sample emission intensity dependence on the pumping power were performed to explain the up conversion mechanism. The CIE chromaticity coordinates (x, y) for white emission in X-2-Y2SiO5 nanocrystalline form were found to be (0.334, 0.332) under 950 nm laser diode excitation. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.Publication Metadata only Field Responsive Fluids - a Review(TRANS TECH PUBLICATIONS LTD, LAUBLSRUTISTR 24, CH-8717 STAFA-ZURICH, SWITZERLAND, 2012-01-01) GENÇ, SEVAL; GENÇ S., DERİN C. B.Magnetorheological (MR), Electrorheological (ER), and Ferrofluids are considered as a class of smart materials due to their novel behavior under an external stimulus such as a magnetic and electrical field. The behavior of these synthetic fluids offer techniques for achieving efficient heat and mass transfer, damping, drag reduction, wetting, fluidization, sealing, and more. Magnetorheological fluids are suspensions of non-colloidal, multi-domain and magnetically soft particles organic and aqueous liquids. Electrorheological fluids are suspensions of electrically polarizable particles dispersed in electrically insulating oil. Ferrofluids are known as magnetic liquids that are colloidal suspensions of ultrafine, single domain magnetic particles in either aqueous or non-aqueous liquids. In this review article a history of these fluids is given, together with a description of their synthesis in terms of stability and redisperibility and how it is understood in various parts of the science and technology. Then the structural changes and rheological properties of these smart fluids under an external stimulus together with a series of applications are presented.