Materials Science and Engineering / Malzeme Bilimi ve Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4719
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Review Citation - WoS: 10Citation - Scopus: 14A Review on Characterization and Recyclability of Pharmaceutical Blisters(Elsevier, 2023) Capkin, Irem Yaren; Gokelma, MertolPackaging is one of the biggest sectors in the world and the use of aluminium is widespread in the packaging industry. Pharmaceutical blister packages generate a significant amount of solid waste, typically containing plastics and aluminium as thin layers. Since these packages have a complex structure with multiple layers, they are hard to recycle. A separation process of the plastic and aluminium is needed prior to recycling. Hydrometallurgical or thermal processes can be used for the separation. This work reviews the characterization of different types of blisters and the different reagents used in the separation process of the blister layers. Parameters and results of separation processes by using hydrochloric acid, formic acid, acetic acid, organic solvents, and phosphoric acid were discussed as well as the thermal degradation.Article Citation - WoS: 8Citation - Scopus: 8Design and Performance Comparison of Polymer-Derived Ceramic Ambigels and Aerogels(American Chemical Society, 2023) Soraru, Gian Domenico; İçin, Öykü; Semerci, Tuğçe; Ahmetoğlu, Çekdar VakıfThis work reports the synthesis and characterization of preceramic-and polymer-derived SiOC aerogels obtained from a commercial siloxane resin. The preceramic aerogels were obtained by ambient pressure drying (ambigels) and CO2 supercritical drying. Despite different drying processes, the final ceramic ambi/aerogels have very similar microstructural features in density, porosity, pore size, and specific surface area. Both materials have shown promising results for oil sorption and water cleaning. Supercritically dried-SiOC aerogel had low thermal conductivity with 0.046 W.m(-1).K-1 at RT and 0.073 W.m(-1).K-1 at 500 degrees C. These results suggest that substituting the rather complicated and expensive CO2-SC drying with the more friendly and cheap ambient pressure drying can be done without having to accept significant microstructural/property degradation.Article Citation - WoS: 3Citation - Scopus: 6Investigation of the Influence of High-Pressure Torsion and Solution Treatment on Corrosion and Tribocorrosion Behavior of Cocrmo Alloys for Biomedical Applications(MDPI, 2023) Yılmazer, Hakan; Caha, İhsan; Dikici, Burak; Toptan, Fatih; Işık, Murat; Niinomi, Mitsuo; Nakai, Masaaki; Alves, Alexandra CruzIn this study, the influence of the high-pressure torsion (HPT) processing parameters and solution treatment (ST) on the corrosion and tribocorrosion behavior of CoCrMo (CCM) alloys was investigated for possible usage in biomedical applications. The corrosion behavior of the CCM alloys was investigated by using potentiodynamic scanning (PDS) and electrochemical impedance spectroscopy (EIS) tests. Tribocorrosion tests were carried out in a reciprocating ball-on-plate tribometer at 1 Hz, 1 N load, and 3 mm stroke length for 2 h. All electrochemical measurements were performed using a potentiostat in standard phosphate-buffered saline (PBS) solution at body temperature (37 +/- 2 degrees C). The samples were characterized by using a scanning electron microscope (SEM), transmission electron microscope (TEM), optical microscope (OM), and X-ray diffraction (XRD). The deepness and width of wear tracks were examined by using a profilometer. The results showed that HPT and ST processes did not affect significantly the corrosion resistance of samples. However, the ST-treated samples had a higher material loss during sliding in standard phosphate-buffered saline (PBS) at body temperature as compared to HPT-treated samples.Review Citation - WoS: 41Citation - Scopus: 42Review on the Parameters of Recycling Ndfeb Magnets Via a Hydrogenation Process(American Chemical Society, 2023) Habibzadeh, Alireza; Küçüker, Mehmet Ali; Gökelma, MertolRegarding the restrictions recently imposed by China on the export of rare-earth elements (REEs), the world may face a serious challenge in supplying some REEs such as neodymium and dysprosium soon. Recycling secondary sources is strongly recommended to mitigate the supply risk of REEs. Hydrogen processing of magnetic scrap (HPMS) as one of the best approaches for magnet-to-magnet recycling is thoroughly reviewed in this study in terms of parameters and properties. The processes of hydrogen decrepitation (HD) and hydrogenation-disproportio-nation-desorption-recombination (HDDR) are two common methods for HPMS. Employing a hydrogenation process can shorten the production route of new magnets from the discarded magnets compared to other recycling routes such as the hydrometallurgical route. However, determining the optimal pressure and temperature for the process is challenging due to the sensitivity to the initial chemical composition and the interaction of temperature and pressure. Pressure, temperature, initial chemical composition, gas flow rate, particle size distribution, grain size, and oxygen content are the effective parameters for the final magnetic properties. All these influencing parameters are discussed in detail in this review. The recovery rate of magnetic properties has been the concern of most research in this field and can be achieved up to 90% by employing a low hydrogenation temperature and pressure and using additives such as REE hydrides after hydrogenation and before sintering.Article Citation - WoS: 18Citation - Scopus: 22Biomimetic Dentin Repair: Amelogenin-Derived Peptide Guides Occlusion and Peritubular Mineralization of Human Teeth(American Chemical Society, 2023) Fong, Hanson; Hamann, John; Hall, Eric; Yücesoy, Deniz T.; Doğan, Sami; Sarıkaya, MehmetExposure of dentin tubules due to loss of protective enamel (crown) and cementum (root) tissues as a result of erosion, mechanical wear, gingival recession, etc. has been the leading causes of dentin hypersensitivity. Despite being a widespread ailment, no permanent solution exists to address this oral condition. Current treatments are designed to alleviate the pain by either using desensitizers or blocking dentin tubules by deposition of minerals or solid precipitates, which often have short-lived effects. Reproducing an integrated mineral layer that occludes exposed dentin with concomitant peritubular mineralization is essential to reestablish the structural and mechanical integrity of the tooth with long-term durability. Here, we describe a biomimetic treatment that promotes dentin repair using a mineralization directing peptide, sADP5, derived from amelogenin. The occlusion was achieved through a layer-by-layer peptide-guided remineralization process that forms an infiltrating mineral layer on dentin. The structure, composition, and nanomechanical properties of the remineralized dentin were analyzed by cross-sectional scanning electron microscopy imaging, energy dispersive X-ray spectroscopy, and nanomechanical testing. The elemental analysis provided calcium and phosphate compositions that are similar to those in hydroxyapatite. The measured average hardness and reduced elastic modulus values for the mineral layer were significantly higher than those of the demineralized and sound human dentin. The structural integration of the new mineral and underlying dentin was confirmed by thermal aging demonstrating no physical separation. These results suggest that a structurally robust and mechanically durable interface is formed between the interpenetrating mineral layer and underlying dentin that can withstand long-term mechanical and thermal stresses naturally experienced in the oral environment. The peptide-guided remineralization procedure described herein could provide a foundation for the development of highly effective oral care products leading to novel biomimetic treatments for a wide range of demineralization-related ailments and, in particular, offers a potent long-term solution for dentin hypersensitivity.Article Citation - WoS: 20Citation - Scopus: 22Fabrication and Properties of Novel Porous Ceramic Membrane Supports From the (sig) Diatomite and Alumina Mixtures(Elsevier, 2022) Aouadja, Faycal; Bouzerara, Ferhat; Güvenç, Çetin Meriç; Demir, Mustafa M.In this paper, the manufacturing of macro-porous tubular ceramic supports for membranes is described. The novel supports are fabricated from natural diatomite and alumina raw materials using the extrusion method. The structure was analyzed by X-ray diffraction (XRD) and mercury porosimetry techniques; the presence of possible defects was investigated by scanning electron microscopy (SEM). The permeability has been measured from water flux in standard experiments. Experimental results show that the open porosity, the average pore size (APS), the pore size distribution, the strength, and the permeability of sintered supports, have been found to depend, mainly on the concentration of alumina (Al2O3) additive. Supports prepared with the addition of 10 wt.% of alumina and sintered at 1200 degrees C, can be considered as the most optimized; they have a porosity ratio of about 46%, an APS is around 7.7 mu m, a flexural strength value of about 28 MPa, and water permeability of around 15 m(3)h(-1) m(-2) bar(-1). Such materials could be of great interest in the supports fabrication for membrane application, for instance, water filtration. (C) 2021 SECV. Published by Elsevier Espana, S.L.U.Article Citation - WoS: 22Citation - Scopus: 21Preparation of Interconnected Pickering Polymerized High Internal Phase Emulsions by Arrested Coalescence(American Chemical Society, 2022) Sherborne, Colin; Reilly, Gwendolen C.; Claeyssens, Frederik; Durgut, Enes; Aldemir Dikici, BetülEmulsion templating is a method that enables the production of highly porous and interconnected polymer foams called polymerized high internal phase emulsions (PolyHIPEs). Since emulsions are inherently unstable systems, they can be stabilized either by surfactants or by particles (Pickering HIPEs). Surfactant-stabilized HIPEs form materials with an interconnected porous structure, while Pickering HIPEs typically form closed pore materials. In this study, we describe a system that uses submicrometer polymer particles to stabilize the emulsions. Polymers fabricated from these Pickering emulsions exhibit, unlike traditional Pickering emulsions, highly interconnected large pore structures, and we related these structures to arrested coalescence. We describe in detail the morphological properties of this system and their dependence on different production parameters. This production method might provide an interesting alternative to poly-surfactant-stabilized-HIPEs, in particular where the application necessitates large pore structures.Article Citation - WoS: 10Citation - Scopus: 11Improved Tribocorrosion Behavior Obtained by In-Situ Precipitation of Ti2c in Ti-Nb Alloy(MDPI, 2022) Gonçalves, Vinícius Richieri Manso; Çaha, İhsan; Alves, Alexandra Cruz; Toptan, Fatih; Rocha, L. A.Novel in-situ Ti-based matrix composites (TMCs) were developed through the reactive hot pressing of Ti + NbC powder blends. Due to the chemical reaction that occurred in the solid-state during processing, the produced samples were composed of an Nb-rich β-Ti phase that formed a metallic matrix along with Ti2C as a reinforcing phase. By employing different proportions of Ti:NbC, the phase composition of the alloys was designed to contain different ratios of α-Ti and β-Ti. The present work investigated the corrosion and tribocorrosion behavior of the composites, compared to unreinforced Ti, in a phosphate-buffered solution (PBS) at body temperature. Corrosion tests included potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Tribocorrosion tests were carried out using a ball-on-plate tribometer with sliding performed at open circuit potential (OCP) and under anodic potentiostatic conditions. Results showed that the stabilization of the β phase in the matrix led to a decrease in the hardness. However, the formation of the in-situ reinforcing phase significantly improved the tribocorrosion behavior of the composites due to a load-carrying effect, lowering the corrosion tendency and kinetics under sliding. Furthermore, localized corrosion was not observed at the interface between the reinforcing phase and the matrix.Review Citation - WoS: 44Citation - Scopus: 48Review on Polymeric, Inorganic, and Composite Materials for Air Filters: From Processing To Properties(John Wiley and Sons Inc, 2021) Henning,L.M.; Abdullayev,A.; Vakifahmetoglu,C.; Simon,U.; Bensalah,H.; Gurlo,A.; Bekheet,M.F.Particulate and gaseous air pollutants pose a threat to human health and contribute to climate change. By today, air filters, stationary and portable, are markedly improved and can often provide innocuous air pollution levels. After introducing the classification and standards on air filters, the influence of the processing route and its parameters on the resulting air filter properties and consequently its performance are discussed. Numerous tools are presented to adjust structural properties such as fiber or pore diameter, specific surface area, surface charge, hydrophilicity, or photocatalytic activity to achieve the desired performance in terms of high filtration efficiencies, sufficient mechanical stability, regeneration eligibility, antimicrobial and optical properties. In particular, inorganic and composite materials as well as nonfibrous structures are covered, which are currently holding an outsider position in an air filter community dominated by polymeric materials and fibrous structures. © 2021 The Authors. Advanced Energy and Sustainability Research published by Wiley-VCH GmbH.Article Citation - WoS: 18Citation - Scopus: 22Effect of Fomes Fomentarius Cultivation Conditions on Its Adsorption Performance for Anionic and Cationic Dyes(American Chemical Society, 2022) Henning, Laura M.; Simon, Ulla; Abdullayev, Amanmyrat; Schmidt, Bertram; Pohl, Carsten; Nunez Guitar, Tamara; Ahmetoğlu, Çekdar Vakıf; Meyer, Vera; Bekheet, Maged F.; Gurlo, AleksanderLab-cultivated mycelia of Fomes fomentarius (FF), grown on a solid lignocellulose medium (FF-SM) and a liquid glucose medium (FF-LM), and naturally grown fruiting bodies (FF-FB) were studied as biosorbents for the removal of organic dyes methylene blue and Congo red (CR). Both the chemical and microstructural differences were revealed using X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, zeta potential analysis, and scanning electron microscopy, illuminating the superiority of FF-LM and FF-SM over FF-FB in dye adsorption. The adsorption process of CR on FF-LM and FF-SM is best described by the Redlich-Peterson model with β constants close to 1, that is, approaching the monolayer Langmuir model, which reach maximum adsorption capacities of 48.8 and 13.4 mg g-1, respectively, in neutral solutions. Adsorption kinetics follow the pseudo-second-order model where chemisorption is the rate-controlling step. While the desorption efficiencies were low, adsorption performances were preserved and even enhanced under simulated dye effluent conditions. The results suggest that F. fomentarius can be considered an attractive biosorbent in industrial wastewater treatment and that its cultivation conditions can be specifically tailored to tune its cell wall composition and adsorption performance.