PubMed İndeksli Yayınlar Koleksiyonu / PubMed Indexed Publications Collections

Permanent URI for this collectionhttps://hdl.handle.net/20.500.13091/5

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Citation - WoS: 11
Citation - Scopus: 9
Capture and Release Recyclable Dimethylaminomethyl-Calixarene Functional Cloths for Point-Of Removal of Highly Toxic Chromium Water Pollutants
(AMER CHEMICAL SOC, 2020) Bieber, Vera S.; Özçelik, Egemen; Cox, Harrison J.; Ottley, Christopher J.; Ratan, Jatinder K.; Karaman, Mustafa; Badyal, Jas Pal S.
Chromium(VI) contamination of drinking water arises from industrial activity wherever there is a lack of environmental legislation enforcement regarding the removal of such pollutants. Although it is possible to remove such harmful metal ions from drinking water through large-scale facilities, there currently exists no safe and simple way to filter chromium(VI) oxoanions at the point of use (which is potentially safer and necessary in remote locations or humanitarian scenarios). High-surface-area cloth substrates have been functionalized with calixarene molecules for the selective capture of aqueous chromium(VI) oxoanions in the presence of structurally similar anions. This is accomplished by pulsed plasmachemical deposition of a linker layer and subsequent functionalization with dimethylaminomethyl-calixarene (5,11,17,23-tetrakis [(dimethylamino)methyl]-25,26,27,28-tetrahydroxycalix[4]arene. Chromium(VI) oxoanions are captured by simply passing polluted water through the functionalized cloth, while other ions not harmful/beneficial to human health remain in the water. These cloth filters are simple to use, highly selective, and easily recyclable-thus making them attractive for point-of-use application in geographic regions lacking appropriate wastewater treatment plants or flawed environmental monitoring systems. Chromium(VI) pollutants have been successfully removed from real-world contaminated industrial wastewater streams using the dimethylaminomethyl-calixarene functionalized cloths.
Carbon Nanotube-Supported Bimetallic Core-Shell (m@pd/Cnt (m: Zn, Mn, Ag, Co, V, Ni)) Cathode Catalysts for H2o2 Fuel Cells
(AMER CHEMICAL SOC, 2023) Yapıcı, Burak; Gökdoğan Şahin, Özlem
M@Pd/CNT (M: Zn, Mn, Ag, Co, V, Ni) core-shell and Pd/CNT nanoparticles were prepared by sodium borohydride reduction and explored as cathode catalysts for the hydrogen peroxide reduction reaction. Electrochemical and physical characterization techniques are applied to explore the characteristics of the produced electrocatalysts. The cyclic voltammetry (CV) experiments show that Zn@Pd/CNT-modified electrodes have a current density of 273.2 mA cm(-2), which is 3.95 times higher than that of Pd/CNT. According to the chronoamperometric curves, Zn@Pd/CNT has the highest steady-state current density for the H2O2 electro-reduction process among the synthesized electrocatalysts. Moreover, electrochemical impedance spectroscopy (EIS) spectra confirmed the previous electrochemical results due to the lowest charge transfer resistance (35 Omega) with respect to other electrocatalysts.
Citation - WoS: 13
Citation - Scopus: 15
Shear Performance in Reinforced Concrete Beams With Partial Aggregate Substitution Using Waste Glass: a Comparative Analysis Via Digital Imaging Processing and a Theoretical Approach
(AMER CHEMICAL SOC, 2024) Zeybek, Özer; Basaran, Bogachan; Aksoylu, Ceyhun; Karalar, Memduh; Althaqafi, Essam; Beskopylny, Alexey N.; Stel'makh, Sergey A.
The usage of waste glass aggregate (WGA) associated with the replacement of fine aggregate (FA) and coarse aggregate (CA) is observed to reduce the number of raw materials for sustainable concrete. For this aim, a total of 15 beams were produced, and then investigational experiments were implemented to observe the shear performances. The stirrup spacing and WGA proportion were chosen as the main parameters. FA and CA were exchanged with WGA with weight proportions of 0, 10, and 20%. The experimental investigation results showed that changing stirrup spacing and WGA proportion affected the fracture and shear properties of reinforced-concrete-beams (R-C-Bs). Furthermore, the findings of the test results revealed that the proportion of WGA could be efficiently consumed as 20% of the partial replacement of FA. With the addition of FA to the mixture, the load carrying capacity of R-C-Bs increases. On the other hand, increasing the WGA ratio by more than 10% using CA, together with increasing the stirrup spacing, can significantly reduce the capacity of R-C-Bs. It was observed that the calculated shear strengths of R-C-Bs with inadequate stirrup spacing, based on ACI 318 and EC2 design codes, can be up to 52 and 79% higher than the experimental results for R-C-Bs containing coarse glass aggregate and 21 and 56% higher for R-C-Bs containing fine glass aggregate, respectively. Additionally, an image processing method was applied to describe the damages/microdamages in R-C-Bs. At that point, the findings obtained from the experimental part of the study were confirmed by the results of the image processing method. Although the strains obtained with the image processing method are reliable, it has not been determined exactly where the crack will occur due to the very sudden development of the shear crack at the moment of beam failure.
Citation - WoS: 20
Citation - Scopus: 19
Vapor Deposition of Transparent Antifogging Polymeric Nanocoatings
(AMER CHEMICAL SOC, 2021) Yılmaz, Kurtuluş; Gürsoy, Mehmet; Karaman, Mustafa
This study demonstrates the coating of a transparent and robust organic thin film having an excellent hydrophilicity-based antifogging property by an initiated chemical vapor deposition (iCVD) method. iCVD was able to synthesize linear and cross-liked poly(acrylic acid) (PAA) from the vapors of acrylic acid (AA) and ethylene glycol dimethacrylate (EGDMA) using tert-butyl peroxide (TBPO) as an initiator. High deposition rates of up to 35 nm/min were observed at low deposition temperatures. It was possible to control the quantity of comonomers in the as-deposited films by adjusting the partial pressure of the EGDMA cross-linking agent. The effect of the EGDMA partial pressure on chemical structure was studied using Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) techniques. FTIR and XPS spectra of the as-deposited films showed the complete retention of the monomer functionality during iCVD. Hydrophilicities and large-area uniformity of the coatings were revealed using water contact angle measurements. The as-deposited PAA film was the most hydrophilic with a water contact angle (WCA) of 7.0 degrees, while cross-linking with EGDMA increased the WCA values by up to 51.7 degrees. Results of various tests, which were based on exposing the coated surfaces to artificial fog and hot water vapor, showed the excellent antifogging property of the coatings. Films were never fogged upon extensive and long-term exposure (2 months) to humid air.

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