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Öğe Additive manufacturing of bionanomaterials for biomedical applications based on TI6AL4V and PLA: a systematic review(EDP Sciences, 2023) Evlen, H.; Ziyamukhamedova, U.; Juraev, D.; Abdukarimov, M.Additive manufacturing (AM) is the owner of a huge potential as a manufacturing technology in fabricating functional implants, and scaffolds for biomedical applications. AM, which includes 3D printing (3DP) and 3D bioprinting, can be the solution to produce several needs such as scaffolds/implants, tissue or organs, or medical devices by combining different biomaterials with nanomaterials. Titanium and its alloys and Polylactic acid (PLA) are commonly used in bone tissue repair with their superior bio-functionality. The rapid advancement of three-dimensional (3D) printing technology has enabled the fabrication of porous titanium and polymer composite scaffolds with controllable microstructures, which is regarded as an effective method for promoting rapid bone repair. An electronic literature search was conducted in PubMed, Web of Science, Scopus, Elsevier, Embase, and other numerous databases up to December 2021 which are accessed by Karabuk university. To evaluate the possibility of bias and methodological quality, the SYRCLE tool and the last version of the CAMARADES list were used, respectively, a meta-analysis could not be performed. This systematic review is aimed to evaluate the common biomedical potential of 3D-printed porous Ti6Al4V (Ti64) and PLA matrix scaffold for repairing bone defects to investigate the influential factors that might affect its osteogenic availability. The most ideal parameters for designing the Ti64 scaffold were found to be a pore size of around 300-400 m and porosity of 60-70%, while PLA scaffolds show 350-400 m and nearly the same percentage in porosity as Ti64. © 2023 EDP Sciences. All rights reserved.Öğe Biological and Morphological Effects of Apatite Kinds (Sheep/Synthetic) on MgO Reinforced Bone Tissue with Hydroxyapatite Matrix(Polish Acad Sciences Inst Physics, 2022) Ari, A. Akilli; Evlen, H.; Demirkol, N.In this study, the biological and morphological structure of the bone tissue of hydroxyapatite produced from synthetic and natural bone was investigated. For this purpose, a three-dimensional bioprinter was designed and manufactured. For the production of bone tissue scaffolds, 10 wt% magnesium oxide added to synthetic hydroxyapatite and sheep hydroxyapatite bioink composites were prepared. The rheological analysis of the prepared bioinks was carried out. With the produced three-dimensional bioprinter, 10 x 10 x 2 mm(3) bone tissue scaffolds were bioprinted. Calcium chloride was used to form connective tissue between layers. 4 weeks of in-vitro bioactivity tests were applied in order to observe the behavior of the produced bone scaffolds and the formation of apatite in the body. After the bioactivity tests, scanning electron microscope and energy dispersive spectrometry analyzes were performed. In addition, a 3-4,5-dimethyl-thiazoly1-2,5-diphenyltetrazolium bromide test was performed in the laboratory environment of the bone tissue scaffolds. In this test, cytotoxicity analyses and cell counts were performed by fibroblast and osteoblast cell loading. Viability and cell proliferation were observed using the phalloidin staining method, and comparisons were made between the mixtures. As a result of the study, the printing ability of both bioinks on the three-dimensional bioprinter was successful. Thus, the bone tissue scaffold of the printed bioink was produced in the desired porous structure. Apatite formations were observed in the scanning electron microscope images of the bone tissue scaffolds that were kept in artificial body fluid for 4 weeks. In the cell culture analysis performed at the last stage with cell viability analysis, the continuation of cell viability was promising.Öğe Effect of extrusion ratio on the wear behaviour of Al-Si and Al-Mg alloys(Elsevier Science Sa, 2012) Demirci, H. I.; Evlen, H.In this study, the wear behaviour of hot extruded Al-Si and Al-Mg alloys was investigated under dry conditions. Die cast Al-Mg alloy containing 1.7% Mg and Al-Si alloy containing 3.3% Si were extruded at 1.6 and 2 ratios. Mechanical and microstructural characterisations of the extruded alloys were carried out through optical microscopy, hardness measurements and tensile testing. Wear tests were carried out on a pin-on-disc type wear device and the worn surfaces were examined under a scanning electron microscope (SEM). The wear test results revealed that the extrusion ratio had an influence on the wear rate and that the samples extruded at a ratio of 1.6 had a lower wear resistance than the ones extruded at a ratio of 2. (C) 2011 Elsevier B.V. All rights reserved.Öğe Effects of Carbon Nanotube Ratio on Mechanical and Morphological Properties of A356-Carbon Nanotube Composites(Polish Acad Sciences Inst Physics, 2019) Evlen, H.; Akcaer, E.In this study, CNT-A356 composites were obtained by reinforcing an aluminium alloy A356 matrix with 4 different ratios (0.5, 1, 1.5 and 2%) of carbon nanotubes, and hardness, wear and microstructure properties of these composites were investigated. Powder metallurgy method was used for producing composites. A356 powders and CNTs were mixed via ball milling for 1 h, and cold pressed in powder pressing mold. After that, mold was taken into a functional furnace, and hot pressing operation was carried out. Pressed bulk was sintered in a vacuum atmosphere (10(-6) mbar) at 550 degrees C for 1 h. Hardness measurements, wear tests, and microstructure analyses of produced samples were performed. As a result of experimental studies, CNTs were observed to be located as agglomeration among matrix grains, and a more hollow structure was formed by increasing CNT ratio. Moreover, weight loss increased as hardness values decreased when CNT ratio exceeded 1%. The highest hardness value was measured in composite with 1% CNT.Öğe Investigation thermal and mechanical properties of PP/beech flour composite(Bulgarian Acad Science, 2017) Kadi, C.; Evlen, H.; Ozmert, A.Composite materials are put into use while their properties are improved by the researchers each passing day due to the advantages they provide and their variety in the application fields. One such renewable material is wood flour which is one of the most common forms of reinforcement in thermoplastics. Wood plastic composites (WPCs) are preferred in our study due to their advantages such as good resistance, low costs, availability and low wear on the processing equipment. In this study beech tree flour and polypropylene (PP) composites were produced and this composites mechanical properties were investigated. It has been observed that 5 composites which were produced by increasing the beech flour by 5wt%, have increased in Elasticity Module and hardness based on the ratio of the beech flour but on the other hand, its elongation and tensile strength has decreased. PP-20% beech flour mixture is seen to have the highest Elasticity Module and hardness. 61% decrease has been observed in tensile strength with the increasing flour ratio. Characterization of PP and PP-Wood beech composites has been carried out via thermal analysis and SEM methods.Öğe Modeling of the process of mechano activation of filler particles in polymer composites(EDP Sciences, 2023) Ziyamukhamedova, U.; Evlen, H.; Nafasov, J.; Jalolova, Z.; Turgunaliyev, E.; Rakhmatov, E.The article presents the results of the study of the filler particles activation mechanism in the production of composite polymeric materials modified by mechanical activation. The studies were conducted in simulated conditions of motion of filler particles taking into account the trajectory of motion during milling in progressive-rotational activation units using analytical expression of velocity distribution of each filler particle in the composite material. © 2023 EDP Sciences. All rights reserved.
