Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
Browse
4 results
Search Results
Article Citation - WoS: 7Citation - Scopus: 8Lithium Extraction From Aqueous Systems by Λ-mno<sub>2</Sub>-deposited Pu Electrospun Mats(Amer Chemical Soc, 2023) Akgun, Berk; Baba, Alper; Demir, Mustafa M.There has been a strong increase in demand for lithium, so the extraction of lithium from natural water resources has become a remarkable remedy to reduce the harmful environmental impact of conventional lithium extraction processes. One of the most effective methods of separating lithium from natural water sources is adsorption using lithium ion sieves as adsorbents. However, the powdered nature of the adsorbents makes them challenging to process. In this study, flexible and free-standing polyurethane (PU) electrospun mats associated with lambda-MnO2 particles were fabricated to extract lithium from aqueous systems. Bead-free and smooth nanofibers were electrospun from a volumetric mixture of DMF:THF (1:2) at 30 wt % of PU solution. lambda-MnO2 powder was deposited on the electrospun mat by vacuum-assisted deposition. The lithium extraction performance of the mats was found to be 21% using single-layer filtration and increased to 77% with multistage filtration. Moreover, using the optimized conditions, lithium extraction achieved up to 14% in a spiked brine sample taken from Lake Tuz (Central Anatolia, Turkey), where the Mg2+/Li+ ratio is higher than 85.Article Citation - WoS: 11Citation - Scopus: 11Enhanced Electrocaloric Effect of P(vdf-Trfe) Nanocomposites With Ca and Sn Co-Doped Batio3 Particles(Elsevier, 2023) Tokkan, Melike; Demir, Mustafa M.; Adem, UmutWe report on the enhancemenent of electrocaloric effect in solution cast polymer nanocomposites based on Poly (vinylidene fluoride-co-trifluoroethylene) [P(VDF-TrFE) 55-45] with Ca and Sn co-substituted BaTiO3 ceramic fillers (Ba0.94Ca0.06Ti0.925Sn0.075O3, BCST). Saturated hysteresis loops and normal ferroelectric behaviour of the copolymer-based nanocomposites-as opposed to the relaxor ferroelectric nature of the terpolymer-based ones-allow the utilization of the indirect method to estimate the electrocaloric properties. Both the dielectric constant and electrocaloric temperature change (AT) increases as the particle content increases. Maximum adiabatic temperature change was obtained as 6.96 K under 900 kV/cm for the 10 vol % BCST containing polymer composite around the Curie temperature of the copolymer (70 degrees C). This relatively large electrocaloric strength is slightly lower than those obtained for terpolymer-based nanocomposites.Article Citation - WoS: 4Citation - Scopus: 10Characterization of Sb Scaling and Fluids in Saline Geothermal Power Plants: a Case Study for Germencik Region (büyük Menderes Graben, Turkey)(Pergamon-Elsevier Science Ltd, 2021) Tonkul, Serhat; Baba, Alper; Demir, Mustafa M.; Regenspurg, SimonaTurkey is located on the seismically active Alpine-Himalayan belt. Although tectonic activity causes seismicity in the Anatolian plate, it also constitutes an important geothermal energy resource. Today, geothermal energy production is heavily concentrated in Turkey's Western Anatolia region. Graben systems in this region are very suitable for geothermal resources. The Buyuk Menderes Graben (BMG) is an area of complex geology with active tectonics and high geothermal potential power. Germencik (Aydin) is located in the BMG, where the geothermal waters include mainly Na-Cl-HCO3 water types. This study examined the stibnite scaling formed in the preheater system of the Germencik Geothermal Field (GGF). The formation of the stibnite scaling on the preheater system dramatically reduces the energy harvesting of the GGF. Considering the stibnite scaling in the surface equipment, the optimum reinjection temperature was determined as 95 degrees C to prevent stibnite scaling in the GGF.Article Citation - WoS: 22Citation - Scopus: 25Cryopreservation of a Cell-Based Biosensor Chip Modified With Elastic Polymer Fibers Enabling Ready-To On-Site Applications(Elsevier, 2021) Özsoylu, Dua; Isık, Tuğba; Demir, Mustafa M.; Schoning, Michael J.; Wagner, TorstenAn efficient preservation of a cell-based biosensor chip to achieve a ready-to-use on-site system is still very challenging as the chip contains a living component such as adherent mammalian cells. Herein, we propose a strategy called on-sensor cryopreservation (OSC), which enables the adherent cells to be preserved by freezing (-80 degrees C) on a biosensor surface, such as the light-addressable potentiometric sensor (LAPS). Adherent cells on rigid surfaces are prone to cryo-injury; thus, the surface was modified to enhance the cell recovery for OSC. It relies on i) the integration of elastic electrospun fibers composed of polyethylene vinyl acetate (PEVA), which has a high thermal expansion coefficient and low glass-transition temperature, and ii) the treatment with O-2 plasma. The modified sensor is integrated into a microfluidic chip system not only to decrease the thermal mass, which is critical for fast thawing, but also to provide a precisely controlled micro-environment. This novel cryo-chip system is effective for keeping cells viable during OSC. As a proof-of-concept for the applicability of a ready-to-use format, the extracellular acidification of cancer cells (CHO-K1) was evaluated by differential LAPS measurements after thawing. Results show, for the first time, that the OSC strategy using the cryo-chip allows label-free and quantitative measurements directly after thawing, which eliminates additional post-thaw culturing steps. The freezing of the chips containing cells at the manufacturing stage and sending them via a cold-chain transport could open up a new possibility for a ready-to-use on-site system.