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Öğe Effects of 3D-printed PLA material with different filling densities on coefficient of friction performance(Emerald Group Publishing Ltd, 2023) Şirin, Şenol; Aslan, Enes; Akıncıoğlu, GülşahPurpose The purpose of this study is the investigation of the friction performance of 3D-printed polylactic acid (PLA) at different infill densities. Design/methodology/approach PLA samples were printed with fused filament fabrication (FFF). Friction performance test of PLA samples were performed under 18 N load at 20 min, 40 min and 60 min using a pin-on-disc tester. Diameter deviation, hardness of 3D-printed PLA, weight variation, coefficient of friction, temperature and wear images were chosen as performance criteria. Findings The hardness values of the samples with 30%, 50% and 70% infill density were determined as 93.9, 99.93 and 102.67 Shore D, respectively. The friction of coefficient values obtained in these samples at 20 min, 40 min and 60 min were measured as 0.5737, 0.4454 and 0.3824, respectively. The least deformation occurred in the sample with 50% occupancy rate and during the test period of 20 min. Practical implications The aim of this study was to determine the best friction performance of 3D-printed biodegradable and biocompatible PLA with different infill densities. Originality/value In the literature, several studies can be found on the mechanical characteristics of 3D-printed parts produced with PLA. However, investigations on the wear characterisation of these parts are very limited. In this regard, the friction coefficient results obtained from different infill density of 3D-printed PLA used in this study will significantly contribute to the literature.Öğe Eklemeli İmalat Yöntemiyle Üretilen Farklı Dolgu Yoğunluklarına Sahip Amorf Termoplastik Numunelerin Tribolojik Özelliklerinin İncelenmesi(2022) Akıncıoğlu, Gülşah; Aslan, EnesASA (Akrilonitril Stiren Akrilat) filament üstün özellikleri sayesinde dış mekan uygulamalarında yaygın olarak kullanılmaktadır. Kullanıldığı ortamlardan dolayı aşınmaya maruz kalmaktadır. Bu çalışmada, farklı dolgu yoğunluklarında (%30, %60 ve %90) üretilen numunelerin tribolojik özellikleri araştırılmıştır. Deneylerden önce kaynaşmış filament üretim yöntemi kullanılarak numuneler üretilmiştir. Sürtünme testleri, pin-on disk test cihazında gerçekleştirilmiştir. Numunelerin sürtünme katsayısı, aşınma oranları, sertlik ve çap değerleri ölçülmüştür. Elde edilen sonuçlara göre, dolgu yoğunluklarına bağlı olarak numunelerin tribolojik özelliklerinde çok az değişiklik olduğu anlaşılmıştır. Ayrıca, %90 dolgu yoğunluklu numuneler, diğer numunelere kıyasla daha yüksek sertlik değerleri ve daha düşük aşınma oranları göstermektedir. Çalışma ayrıca, kaynaşmış filament üretim yönteminin, güçlü ASA polimerinden numune üretmek için uygun bir teknik olduğunu göstermektedir.Öğe Honey: An Advanced Antimicrobial and Wound Healing Biomaterial for Tissue Engineering Applications(Mdpi, 2022) Yupanqui Mieles, Joel; Vyas, Cian; Aslan, Enes; Humphreys, Gavin; Diver, Carl; Bartolo, PauloHoney was used in traditional medicine to treat wounds until the advent of modern medicine. The rising global antibiotic resistance has forced the development of novel therapies as alternatives to combat infections. Consequently, honey is experiencing a resurgence in evaluation for antimicrobial and wound healing applications. A range of both Gram-positive and Gram-negative bacteria, including antibiotic-resistant strains and biofilms, are inhibited by honey. Furthermore, susceptibility to antibiotics can be restored when used synergistically with honey. Honey's antimicrobial activity also includes antifungal and antiviral properties, and in most varieties of honey, its activity is attributed to the enzymatic generation of hydrogen peroxide, a reactive oxygen species. Non-peroxide factors include low water activity, acidity, phenolic content, defensin-1, and methylglyoxal (Leptospermum honeys). Honey has also been widely explored as a tissue-regenerative agent. It can contribute to all stages of wound healing, and thus has been used in direct application and in dressings. The difficulty of the sustained delivery of honey's active ingredients to the wound site has driven the development of tissue engineering approaches (e.g., electrospinning and hydrogels). This review presents the most in-depth and up-to-date comprehensive overview of honey's antimicrobial and wound healing properties, commercial and medical uses, and its growing experimental use in tissue-engineered scaffolds.Öğe Hybrid biomanufacturing systems applied in tissue regeneration(Whioce Publ Pte Ltd, 2023) Liu, Fengyuan; Quan, Rixiang; Vyas, Cian; Aslan, EnesScaffold-based approach is a developed strategy in biomanufacturing, which is based on the use of temporary scaffold that performs as a house of implanted cells for their attachment, proliferation, and differentiation. This strategy strongly depends on both materials and manufacturing processes. However, it is very difficult to meet all the requirements, such as biocompatibility, biodegradability, mechanical strength, and promotion of cell-adhesion, using only single material. At present, no single bioprinting technique can meet the requirements for tissue regeneration of all scales. Thus, multi-material and mixing-material scaffolds have been widely investigated. Challenges in terms of resolution, uniform cell distribution, and tissue formation are still the obstacles in the development of bioprinting technique. Hybrid bioprinting techniques have been developed to print scaffolds with improved properties in both mechanical and biological aspects for broad biomedical engineering applications. In this review, we introduce the basic multi-head bioprinters, semi-hybrid and fully-hybrid biomanufacturing systems, highlighting the modifications, the improved properties and the effect on the complex tissue regeneration applications.Öğe Preliminary Characterization of a Polycaprolactone-SurgihoneyRO Electrospun Mesh for Skin Tissue Engineering(Mdpi, 2022) Aslan, Enes; Vyas, Cian; Yupanqui Mieles, Joel; Humphreys, Gavin; Diver, Carl; Bartolo, PauloSkin is a hierarchical and multi-cellular organ exposed to the external environment with a key protective and regulatory role. Wounds caused by disease and trauma can lead to a loss of function, which can be debilitating and even cause death. Accelerating the natural skin healing process and minimizing the risk of infection is a clinical challenge. Electrospinning is a key technology in the development of wound dressings and skin substitutes as it enables extracellular matrix-mimicking fibrous structures and delivery of bioactive materials. Honey is a promising biomaterial for use in skin tissue engineering applications and has antimicrobial properties and potential tissue regenerative properties. This preliminary study investigates a solution electrospun composite nanofibrous mesh based on polycaprolactone and a medical grade honey, SurgihoneyRO. The processing conditions were optimized and assessed by scanning electron microscopy to fabricate meshes with uniform fiber diameters and minimal presence of beads. The chemistry of the composite meshes was examined using Fourier transform infrared spectroscopy and X-ray photon spectroscopy showing incorporation of honey into the polymer matrix. Meshes incorporating honey had lower mechanical properties due to lower polymer content but were more hydrophilic, resulting in an increase in swelling and an accelerated degradation profile. The biocompatibility of the meshes was assessed using human dermal fibroblasts and adipose-derived stem cells, which showed comparable or higher cell metabolic activity and viability for SurgihoneyRO-containing meshes compared to polycaprolactone only meshes. The meshes showed no antibacterial properties in a disk diffusion test due to a lack of hydrogen peroxide production and release. The developed polycaprolactone-honey nanofibrous meshes have potential for use in skin applications.Öğe Tribological characteristics of ABS structures with different infill densities tested by pin-on-disc(Sage Publications Ltd, 2023) Akıncıoğlu, Gülşah; Şirin, Emine; Aslan, EnesAcrylonitrile butadiene styrene (ABS), a petroleum-based thermoplastic, is widely used in various industry. It is important to make product costs without reducing the wear characteristics of products. For this reason, over the past 20 years, researchers have focused on improving product performance by reducing material weight. The literature has limited information about the tribological properties of the ABS polymer samples produced with fused deposition modelling. In this study, gyroid-patterned ABS samples with different infill densities (25%, 50%, and 75%) were produced and the effect on the wear properties of the samples was investigated. The main aim of the study is to show the infill density effect on wear and friction performance of the samples and find the coefficient of friction values. So, this study is one of the first studies which investigated wear and friction properties of ABS polymer produced as gyroid pattern with different infill densities. The study might also be used to have an initial information whether ABS polymer can be used in additive manufacturing systems for the joint components. As the performance indicator, diameter deviation, hardness, surface roughness, test temperature, friction coefficient, weight loss, and wearing surface results of the samples were evaluated. The results show that infill density is an important property that effect the tribological and heating characteristic of ABS samples. The friction and heat of the samples increase by increasing infill density. According to the tribological test results, the highest coefficient of friction and friction temperature were reached in the samples with 75% infill density.Öğe Utilization of waste apricot kernel shell derived-activated carbon as carrier framework for effective shape-stabilization and thermal conductivity enhancement of organic phase change materials used for thermal energy storage(Elsevier, 2022) Hekimoğlu, Gökhan; Sarı, Ahmet; Önal, Yunus; Gencel, Osman; Tyagi, V. V.; Aslan, EnesIn this study, low-cost and eco-friendly AC obtained from waste apricot kernel shells (ACAS) was utilized to simultaneously solve the inherited drawbacks and enhance thermal conductivity of (Capric-Myristic acid (CA-MA), Lauryl alcohol (LAOH), n-Octadecane (OD) and Polyethylene glycol (PEG)) as different type organic PCMs. The ACAS/PCM composites had high PCM loading rates of up to 75 wt%, hence a high latent heat capacity of up to 193.7 J/g. Their melting and freezing temperatures varied in the range of 20.21-26.61 degrees C and 18.37-28.78 degrees C, respectively. All the prepared composites exhibited high thermal degradation resistance as well as high cycling stability even after 1200 melting-freezing cycles. The thermal conductivity of ACAS/CA-MA, ACAS/LAOH, ACAS/OD and ACAS/PEG was measured approximately 2.61, 2.40, 2.27 and 1.75 times higher than that of pure CA-MA, LAOH, OD and PEG, respectively. The advantageous TES characteristics of leak-proof composites make them favourable PCMs for low-temperature thermal management of buildings. (C) 2022 Elsevier B.V. All rights reserved.
