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A comparative study about corrosion resistance and biocompatibility of Ti6Al4V samples produced by wrought and additive manufacturing methods
No full textTi6Al4V is widely used in biomedical applications due to its excellent mechanical properties and biocompatibility. Conventional manufacturing techniques, such as plastic deformation processes, have long been employed to produce Ti6Al4V implants and prosthetics. Recently, the advent of additive manufacturing (AM), which allows the generation of complex geometries and customized implants, has introduced a new dimension to the production of these biomedical devices. However, examining the effects of newly developed manufacturing methods on material and sample properties is extremely important to obtain successful products. In this study, additive manufactured and wrought Ti6Al4V samples were implemented for their corrosion resistance and biocompatibility as orthopedic implant material. Three different post processes such as sandblasting, acid etching and bioactive coating (hydroxyapatite-chitosan composite via electrophoretic deposition (EPD)) were applied on the additive manufactured sample surfaces, while only the bioactive coating was applied on the wrought sample surfaces and their effects on the corrosion and biocompatibility were evaluated with the reference of untreated control samples. Corrosion resistance properties were examined with open circuit potential (OCP) measurement, electrochemical impedance spectroscopy (EIS) and Tafel extrapolation, respectively. Electrochemical impedance spectroscopy and Tafel extrapolation showed similar results. Biocompatibility tests were carried out as mouse embryonic fibroblast (MEF) cell culture and cellular viability tests with mouse embryonic fibroblast cells. Coating and sandblasting were the best post-processing methods for anti-corrosion and biocompatibility applications. AM sandblasted samples are the most suitable samples for both application areas
Predicting the Punching Shear Capacity of RC Slab-Column Connections with FRP Bars Using Machine Learning Based Algorithms
No full textIn this study, two novel machine learning (ML) models, developed using Gene Expression Programming (GEP) and Multi Expression Programming (MEP) algorithms, are proposed for predicting the punching shear capacity of reinforced concrete (RC) slab-column connections with fiber reinforced polymers (FRP) as longitudinal bars. Using the GEP and MEP models, the values of statistical indicators obtained from the training dataset were very close to those values obtained from the testing dataset. In addition, a comparative study was conducted on experimental results and prediction results from the design codes, existing models in the literature and proposed ML models. The comparison revealed that the two models with the highest coefficient of determination (R2) and the lowest mean absolute percentage error (MAPE), root mean square error (RMSE), and coefficient of variation (COV) values belong to the GEP and the MEP model. The results indicated that the proposed GEP and MEP models outperformed the other models in terms of prediction accuracy and robustness. Finally, sensitivity and parametric analyses were conducted
KENT KİMLİĞİNİ YANSITACAK VE İKLİM DEĞİŞİKLİĞİNE UYUM SAĞLAYABİLECEK ODUNSU BİTKİLER: BİTLİS
No full textA systematic approach to the sports scheduling problem for the Turkish professional football league
No full textScheduling of sports competitions has become an area of interest for researchers with the globalization of sports and its spread to large crowds. Round Robin tournament derivatives are generally applied among different types of tournaments, especially in leagues. This study aims to create schedules for the Turkish Professional Football League. Indicators such as the number of breaks, weighted carry-over effect, and specific requirements are considered as characteristic values reflecting the league's quality. In this study, an integer programming (IP) model is developed to solve the scheduling problem, and it is observed that the IP model gives the optimum schedule for small-sized problems only. As a remedy, a two-phase heuristic solution procedure is proposed. The heuristic procedure first finds a pattern set and then constitutes the schedule. Different pattern sets and schedules are presented in the experimental results. The results show that the proposed heuristic method obtains the best schedules concerning the current schedule and the proposed IP models for various problem characteristics
Physico-Mechanical Characterization of Kazakhstan Diatomite–Opacifier Geopolymers under Electrothermal and Conventional Curing
No full textIntertextuality of Identification: Integrating the Creative Acting System and Therme Vals
No full textThis study establishes a theoretical correlation between Konstantin Stanislavski, whose Creative Acting System shaped 20th-century theater, and Peter Zumthor, architect of Therme Vals, a landmark of early 21st-century architecture. While Stanislavski used an actor training method aimed at integrating actors with their characters and guiding them toward an inner transformation, Zumthor emphasizes the sensory and experiential relationship between the user and the space. Building on this parallel, the research argues that architectural space can be analyzed through the Creative Acting System. As a methodological framework, the Four C Model of Creativity (Kaufman & Beghetto) is employed to structure the interdisciplinary dialogue between theater and architecture. Within a linear Text–Action–Space triad, Lacan and Merleau-Ponty are positioned under the Text category (mini-C and little-C), Stanislavski under Action (Pro-C), and Zumthor’s Therme Vals under Space (Big-C). Through this method, the philosophical foundations of Stanislavski and the psychoanalytic theories that informed it emerge in the design of Therme Vals, where Zumthor’s architecture engages in intertextual production. This study, employing a qualitative research method, aims to lay the groundwork for future multidisciplinary investigations.</p
KENT KİMLİĞİNİ YANSITACAK VE İKLİM DEĞİŞİKLİĞİNE UYUM SAĞLAYABİLECEK ODUNSU BİTKİLER: ARTVİN
No full textExperimental Investigation of the Effect of Cavity Joining Technique of Gas Ovens on Energy Consumption and the Environment
No full textThis article aims to show the effect of the joining technique of the sheet metal parts of a cavity on energy consumption, energy efficiency class, and environmental impact in domestic gas ovens. An oven cavity can be joined by screwing or welding the metal parts. Experiments were carried out on two identical prototypes, which only differed in the joining method used to assemble the cavity. The energy consumption of the oven with the welded cavity is found to be 12.00–14.22% less than that of the oven with the screwed cavity. The energy efficiency classes of the two ovens were determined. According to the energy efficiency index (EEI) averages of the prototypes, the oven with a screwed cavity (EEI =112.92) is in class B, and the oven with a welded cavity (EEI= 98.38) is in class A. In order to show the environmental impact of the appliances, the carbon footprint of the ovens for nonintense and intense use over a period of 1 year and 10 years was determined. It was found that the carbon footprint from ovens with screwed cavities is 12.92% higher than that of ovens with welded cavities due to excess fuel consumption.[</p
Development of microparticles containing polylactic acid/Bioactive glass/Caffeic acid for bone tissue engineering
No full textBone defects from trauma, fractures, infections, or neoplasms present a significant challenge, driving the need for advanced bone tissue engineering methods. This study combines caffeic acid and bioactive glass in a microparticle system to enhance their synergistic effects and boost bone regeneration by leveraging’s role in cell proliferation and differentiation and osteoconductive properties of bioactive glass. Within the scope of the study, microparticles were produced via electrospray method for four different formulations: 3% polylactic acid, 3% PLA/0.1% bioactive glass, 3% PLA/0.1% caffeic acid, and 3% PLA/0.1% bioactive glass /0.1% caffeic acid. Structural characterizations of microparticles were assessed using SEM, FTIR, DSC, and XRD, while caffeic acid release profiles and biocompatibility with hFOB cells were also evaluated. Structural analyses showed that the average diameter of solely PLA microparticles of 3,54 μm ± 0.58 μm could be increased up to 4.33 μm with bioactive glass and caffeic acid. Thermal analysis indicated that bioactive glass and caffeic acid had a minimal impact on thermal properties, and in vitro tests showed bioactive glass extended caffeic acid release time by up to four times. Biocompatibility tests confirmed no cytotoxicity to hFOB cells, highlighting the potential of Polylactic acid/Bioactive glass/Caffeic acid microparticles for improving bone regeneration
Pigmented wheat whole breads: in vitro phenolic bioaccessibility and colorectal cancer-targeted effects
No full textPigmented wheat varieties, naturally containing phenolic compounds and anthocyanins, have gained attention as potential functional foods. This study aimed to assess the in vitro bioaccessibility of individual phenolics and antioxidant capacities (ABTS, DPPH, and FRAP assays) in whole wheat breads prepared from red, purple, blue, and black wheats, and to compare their anticancer effects against HCT-15 colorectal cancer cells. Whole wheat breads were formulated using four distinct pigmented wheats. An in vitro gastrointestinal digestion model was applied to simulate human digestion, followed by fractionation into serum-accessible (IN) and colon-available (OUT) fractions. Total phenolic content (TPC) and antioxidant capacities were quantified, and the extracts’ cytotoxic effects were assessed using HCT-15 cell viability assays. Digestion significantly altered phenolic profiles and antioxidant capacities, with bound phenolics demonstrating enhanced resistance to digestive conditions. After digestion, polyphenols and antioxidant capacity decreased, but they remained potentially bioaccessible. Notably, extracts from purple and blue wheat breads exhibited significantly greater cell viability-reducing activity against HCT-15 cells compared to red or black wheat extracts, suggesting a higher release and bioactivity of phenolics in these varieties. The superior inhibitory potency of purple and blue wheat breads highlights their potential as functional ingredients for the development of nutritionally enhanced wheat-based products, offering promising avenues for colorectal cancer prevention strategies