Akademik Çalışmalar

Bu topluluk için Kalıcı Uri

http://hdl.handle.net/11527/13121
Kurumsal arşive yüklenen tüm eserler telif hakkı ile korunmaktadır. Bunlar, bu kaynak üzerinden herhangi bir amaçla görüntülenebilir, ancak yazılı izin alınmadan herhangi bir biçimde yeniden oluşturulması veya dağıtılması yasaklanmıştır. İzin hakkında istekte bulunmak için URL adresini ziyaret ediniz.

Gözat

Sustainable Development Goal "Goal 9: Industry, Innovation and Infrastructure" ile Akademik Çalışmalar'a göz atma
  • Öge
    10. Uluslararası Lif ve Polimer Araştırmaları Sempozyumu (10. ULPAS) Bildiriler Kitabı: 13-14 Mayıs 2022, İstanbul, Türkiye: Akıllı ve teknik tekstiller / editors, Prof. Dr. Yusuf Ulcay, Prof. Dr. Ali Demir, Doç. Dr. Ali Kılıç, Dr. Gülçin Baysal, Merve Nur Sağırlı
    (İstanbul Teknik Üniversitesi, 2022) ; Tekstil Mühendisliği ; Ulcay, Yusuf ; Demir, Ali ; Kılıç, Ali ; Baysal, Gülçin ; Sağırlı, Merve Nur
    Sempozyumun ana misyonu, lif ve polimer alanındaki çalışan ve araştırmacıları kuruluşlarına ve topluluklarına sürekli olumlu katkıda bulunmaya hazırlamaktır. Uluslararası Elyaf ve Polimer Sempozyumu ULPAS (IF&PRC), sürekli büyüme şartlarına hazır, iyi eğitimli, bağımsız araştırmacıları hazırlamak için özenli bir ortamda proje çalışmalarına dayalı ve nitelikli sempozyum programları sağlamayı amaçlamaktadır. Ayrıca, Lif ve Polimer Araştırma Enstitüsü üyeleri arasında işbirliği ve koordinasyon kurmayı da amaçlamaktadır.
  • Öge
    16. Uluslararası Lif ve Polimer Araştırmaları Sempozyumu, 9-10 Mayıs, 2025, İstanbul Teknik Üniversitesi
    (İTÜ Yayınevi, 2025) Tekstil Mühendisliği ; Ulcay, Yusuf ; Demir, Ali ; Toptaş, Ali ; Bidoki, Seyedmansour ; Çavuşoğlu, Aysu
    ULPAS is fundamentally a thematic symposium, a scientific marketplace where research findings in fibers—the fundamental building blocks of textiles—and polymers—the molecules that form them—are shared with the international community.
  • Öge
    A bibliometric analysis of metaverse technologies in healthcare services
    (Springer, 2024) Damar, Seçkin ; Hançerlioğulları Köksalmış, Gülşah ; 0000-0002-2713-2738 ; 0000-0002-2551-541X ; Endüstri Mühendisliği
    A bibliometric analysis was conducted to examine healthcare metaverse research using 3721 Web of Science publications covering the period 1994–2022. Using bibliometric and bibliographic link network analyses, this study aimed to uncover emerging trends, country and university contributions, author collaborations, and common metaverse themes. Contrary to expectations, inconsistent correlations between publication volume and citation impact emerged. This pioneering research evaluated empirical bibliometric laws, identified influential entities, and provided a structured thematic categorization for metaverse studies. Serving as the first comprehensive investigation of the healthcare metaverse, this study lays a solid foundation for subsequent research efforts and guides further scholarly research.
  • Öge
    A novel image denoising technique with Caputo type space–time fractional operators
    (Springer, 2024) Tanrıöver, Evren ; Kiriş, Ahmet ; Tunga, Burcu ; Tunga, M. Alper ; 0000-0003-4098-3155 ; 0000-0002-3687-6640 ; 0000-0001-7318-964X ; 0000-0003-3551-4549 ; Matematik Mühendisliği
    A novel image denoising model, namely Full Fractional Total Variation (TVFF), based on the Rudin-Osher-Fatemi (ROF) and the fractional total variation models is presented. The leading advantage of TVFF model is that it uses fractional derivatives with length scale parameters instead of ordinary derivatives with respect to both time and spatial variables in the diffusion equation. The Riesz–Caputo fractional derivative operator is used to disperse nonlocal influence throughout all directions, whereas the Caputo fractional derivative concept is employed for time fractional derivatives. Therefore, the influence of neighboring pixels is given greater weight compared to those situated farther away and this reflects the consideration behind denoising process better. Moreover, the numerical approach is constructed, and its stability and convergence properties are thoroughly examined. To show the superiority of our model, the denoised images are subjected to visual and numerical comparisons using metrics such as the Signal-to-Noise Ratio (SNR), the Structural Similarity Index Measure (SSIM) and the Edge-Retention Ratio (ERR). The performance of the TVFF method is evaluated under various types of noise, including Poisson, Speckle, and Salt & Pepper, and the results are compared with those obtained using Gauss and Median Filters. Furthermore, the proposed method is applied to both blind and synthetic images, thereby showcasing its versatility and applicability across diverse datasets. The outcomes showcase the substantial potential of our enhanced model as a versatile and efficient tool for image denoising.
  • Öge
    Alternative plant-based gluten-free sourdough pastry snack production by using beetroot and legumes: characterization of physical and sensorial attributes
    (American Chemical Society, 2024) Yolcu, Zeynep ; Demircan, Evren ; Mertdinç, Zehra ; Aydar, Elif Feyza ; Özçelik, Beraat ; 0000-0002-1810-8154 ; Gıda Mühendisliği
    Objective of this study was to design a formula of a sourdough pastry snack by adding starter inoculum into the formulation which was obtained by the fermentation process through beetroot (Beta vulgaris) puree with black-eyed pea (Vigna unguiculata) and fava bean (Vicia faba). With this development process, it was aimed to review the functional impact of legumes as gluten replacement and emphasize the importance regarding physical and sensory attributes in a pastry snack product. First, a starter inoculum was developed based on modification of the shalgam fermentation process with legumes. An experimental design suggested by the response surface methodology was used to optimize its microbial properties and level of antioxidants with the factors of amounts of beetroot puree, fava bean/black-eyed pea ratio, and fermentation time. In the second part, this starter inoculum was mixed with fava bean flour to obtain a sourdough pastry snack (FBS) with improved physical and sensory attributes and compared to the wheat control sourdough (WCS) pastry snack after the baking process. According to the optimization results to produce starter inoculum with the optimum results of lactic acid bacteria 9.55 log cfu/mL, the level of antioxidant activity 91.86 μM TE/mL, and total yeast level 6.96 log cfu/mL; 75 mL of beetroot puree, 100% for fava bean, and fermentation for 24 h were obtained. Compared to WCS, FBS has approximately 16% higher hardness values. Also, a significant difference was observed for stiffness and springiness among samples. The retention of moisture was higher in the first 4 days following the storage for 8 days; the moisture content continuously decreased with the final moisture content of 12.6%. When compared with the results of textural profile analysis in terms of hardness, stiffness, and springiness, sensory results were correlated. Comparing the overall acceptability of the FBS to WCS, FBS was from moderate to higher scores, which indicated that it could be a promising alternative to chemically developed snack products and a preferred product for people suffering from celiac disease and other gluten intolerances.
  • Öge
    Analytical and numerical modeling on strengths of aluminum and magnesium micro-lattice structures fabricated via additive manufacturing
    (Springer, 2024) Sun, Yeting ; Akçay, Fuzuli Ağrı ; Wu, Dazhong ; Bai, Yuanli ; 0000-0002-5116-0069 ; Makina Mühendisliği
    Bioinspired lattice structures have a wide range of applications in aerospace, automotive, energy, and medical device industries due to their high strength-to-weight ratio. Although experimental and numerical modeling methods have been extensively used to characterize the compressive behavior of lattice structures, an accurate analytical model has great values in material/structure designs and applications. In this study, a new analytical model is developed for two configurations based on limit analysis in the plasticity theory to predict the compressive strengths of micro-lattice structures (MLS). The model is also discussed for determining the amounts of stretching-dominated deformation and bending-dominated deformation. A comparative study is performed between analytical solutions and experimental results of AlSi10Mg (aluminum alloy) and WE43 (magnesium alloy) MLS additively manufactured via selective laser melting (SLM). Finite element simulations using beam elements are conducted to evaluate the accuracy of the analytical solution. Analytical results, finite element simulation results, and the experimental results are in a good agreement with both AlSi10Mg and WE43 MLS. The shear band formation, as a main failure mode of MLS, is also studied and evaluated using the classical Rudnicki–Rice’s criterion, for which a reasonably good accuracy is demonstrated.
  • Öge
    Assessment of geothermal power potential in Buyuk Menderes Basin, Turkey
    (Elsevier, 2020) Yamanlar, Şenol, ; Korkmaz Başel, Emine Didem ; Serpen, Ümran ; https://orcid.org/0000-0001-7713-9551 ; Petroleum and Natural Gas Engineering Department
    Turkey’s installed geothermal capacity for power generation as of December 2019 is 1500 MWe. Most of this installed capacity is generated by the power plants located in the Buyuk Menderes graben. Geologically Buyuk Menderes graben is a huge structure having several discovered geothermal resources and can be considered as a geothermal basin. The aim of this study is to estimate the geothermal power potential of Buyuk Menderes graben. To achieve this object, a stochastic methodology, which is used to evaluate hydrocarbon-bearing basins, is adapted from the oil and natural gas industry. This methodology provides a way to quantify the geothermal potential in a range of possible values by evaluating the individual fields in the basin using stored heat technique. A total of 34 (21 proven and 13 probable occurrences) geothermal fields having medium to high temperature (T ≥ 100 °C) values are evaluated using the Monte Carlo Simulation technique. In these simulations, available geological, geochemical, geophysical data are used along with the data obtained from the drilled wells in the region. The power potential (MWe) values for 21 proven fields in terms of P10, P50 and P90 values are determined to be 888, 1077 and 1311 MWe, respectively. Considering the 13 probable occurrences along with the proven fields, the lower and upper limits of the total power potential (P10 and P90) are 1156 and 1580 MWe, respectively. Moreover, the power potentials are also evaluated under the presence of uncertainty. By assigning 5/13, 6/13, and 7/13 probability values for the 13 probable occurrences, overall geothermal power potential P10 values are estimated as 1041, 1075, and 1101 MWe, respectively.
  • Öge
    Buckling analysis of single-walled carbon nanotubes using the initial value method and approximate transfer matrix based on nonlocal elasticity theory
    (Wiley, 2024) Tepe, Ayşegül ; orcid.org/0000-0001-5612-3526 ; Mathematical Engineering
    In this study, a novel method is presented to analyze the buckling behavior of single-walled carbon nanotubes (SWCNTs) using the initial value method (IVM) in conjunction with the approximate transfer matrix, within the framework of nonlocal elasticity theory. The study aims to accurately approximate critical buckling load parameters under various boundary conditions, without encountering high computational requirements. IVM enables the computation of displacements and stress resultants along the entire beam from given initial conditions. The approximate transfer matrix is employed to analyze system states at different points through successive integration of solutions, generating the principal matrix needed for IVM and ensuring systematic and precise results that optimize the accuracy of the analysis. A convergence study confirms the effectiveness and precision of the proposed method, revealing a decrease in the critical buckling load parameters as the nonlocal parameter increases, applicable across all boundary conditions studied (simply supported, clamped–clamped, clamped–simply supported, and clamped-free). These results underscore the need to incorporate nonlocal effects for more accurate nanostructure mechanics predictions. The integration of IVM and the approximate transfer matrix provides a computationally efficient alternative to traditional numerical and semi-analytical methods, aiding researchers and engineers working with SWCNTs and other nanomaterials.
  • Öge
    Collection: Wound Healing Assay Dataset (WHAD) and Cell Adhesion and Motility Assay Dataset (CAMAD)
    (IEEE Xplore, 2024-10-16) Töreyin, Behçet Uğur ; Iheme, Leonardo O. ; Önal, Sevgi ; Erdem, Yusuf S. ; Uçar, Mahmut ; Yalçın Özuysal, Özden ; Okvur Pesen, Devrim ; Öney, Devrim ; Yapay Zeka ve Veri Mühendisliği
    the Wound Healing Assay Dataset (WHAD) and the Cell Adhesion and Motility Assay Dataset (CAMAD). WHAD comprises time-lapse phase-contrast images of wound healing assays using genetically modified MCF10A and MCF7 cells, while CAMAD includes MDA-MB-231 and RAW 264.7 cells cultured on various substrates. These datasets offer diverse experimental conditions, comprehensive annotations, and high-quality imaging data, addressing gaps in existing resources. The collection methods, experimental designs, and annotation processes are detailed, emphasizing the reliability and utility of our datasets. WHAD and CAMAD enable researchers to develop robust algorithms for cell tracking, segmentation, and behavior analysis in phase-contrast microscopy images. The applications of these datasets span cancer research, image processing technique development, and automated analysis of wound healing and cell motility assays.
  • Öge
    Combination of polyethylenimine and vanillin-based benzoxazine as a straightforward self-healable system with excellent film-forming ability
    (American Chemical Society, 2024) Gülyüz, Sevinç ; Kışkan, Barış ; 0000-0002-3028-6455 ; 0000-0001-9476-2054 ; Kimya Bölümü
    This study introduces a straightforward and efficient route for synthesizing self-healable polybenzoxazine networks by utilizing dynamic imine bond exchanges under mild conditions. The process involves combining polyethylenimines with aldehyde-functional bisbenzoxazine, which was produced from vanillin, using a Sc(OTf)3 catalyst and subjecting them to moderate heating at 150 °C. Remarkably, the resulting polybenzoxazine films exhibit good self-healing capabilities at low temperatures and pressures, without requiring any additional additives to facilitate the healing process. The degree of recovery was assessed through tensile tests, while rheologic measurements were utilized to analyze stress relaxation and activation energy of dynamic bonding, providing insights into the self-healing process. Additionally, comprehensive spectral characterizations and investigations of thermal behaviors were conducted to gain a deeper understanding of the material’s properties and performance. Moreover, the polybenzoxazine networks demonstrated enhanced hydrolysis stability compared to conventional imine-based systems, benefiting from the specific Mannich linkages and inherent hydrophobic nature of polybenzoxazines.
  • Öge
    Combined effects of zein nanofiber coating containing laurel (laurus nobilis) and air fryer cooking on quality properties of fish fillets during cold storage
    (American Chemical Society, 2024) Ceylan, Zafer ; Meral, Raciye ; Alav, Aslıhan ; Torusdağ, Gülşen Berat ; Bildik, Fatih ; Altay, Filiz ; 0000-0002-5484-866X ; Gıda Mühendisliği
    In this study, the effects of zein nanofibers (Zn) containing ground laurel leaves (GLL) and air fry cooking on the quality characteristics of Rainbow trout (Oncorhynchus mykiss) were investigated. The zein nanofibers possessing 335.8 ± 43.6 nm average diameters were fabricated containing GLL. The Fourier transform infrared spectroscopy (FTIR) results of the zein, Zn, GLL, and zein nanofibers containing GLL (LZn) confirmed the electrospinning encapsulation of GLL into Zn and their interactions. The effects of the combination of LZn coating and air fryer cooking of fish fillets on the quality characteristics during storage at 4 °C for 10 days were monitored in terms of oxidative and microbiological stability, color, and sensory parameters. As compared to the control, the combination of LZn coating and air fryer cooking provided a microbial limitation of up to 45.21% during the analysis (p < 0.05). The changes in ΔE values between the control and the LZn-coated samples were obtained as ≤7.56 during 6 days, but then a dramatic color difference was observed. Besides overall sensory acceptability, particularly the odor parameter in the cooked fish samples coated with LZn was significantly preferred (p < 0.05). The combination of LZn coating and air fryer cooking delayed the thiobarbituric acid increase in the fish meat samples (3.51 to 2.57 mg malondialdehyde (MDA)/kg) up to the third day of storage. This study showed that LZn coating is a very functional layer on the fish meat and could be applied for not only fresh fish meat but also other fresh meat products.
  • Öge
    Comparative assessment of material homogenisation techniques
    (Institute for Materials, Technologies and Mechanics, 2024) Tüfekci, Mertol ; Pir, İnci ; Tüfekci, Ekrem ; https://orcid.org/0000-0002-0540-5387 ; https://orcid.org/0000-0003-3991-4005 ; Makina Mühendisliği
    This study evaluates the accuracy and computational demands of Mean Field Homogenisation (MFH) and Finite Element Method-Based Homogenisation (FEMBH) for composites. FEMBH requires generating a Representative Volume Element (RVE) to capture the essential microstructural characteristics. The focus is on nanoparticle-reinforced composites, considering the distinct mechanical properties of matrix and inclusion phases, as well as the influence of inclusion geometry, such as aspect ratio and reinforcement orientation. A comparative numerical analysis of various homogenisation techniques is conducted, assuming linear and elastic behaviour for both phases. Also, different FEMBH implementations are examined, including voxel and tetrahedral meshes, to assess their precision and computational efficiency. To represent the effect of the RVE size choice on the accuracy of the results, different RVE sizes are evaluated during the homogenisation process. The Mori-Tanaka method, representing MFH, demonstrates good accuracy in predicting macroscopic behaviour, while FEMBH, particularly with detailed meshing, yields precise results. However, FEMBH requires significant computational resources, especially with increasing aspect ratios and volume fractions of reinforcing particles, which demand higher mesh densities for accurate analysis.
  • Öge
    Cryo-assisted nitrogen treatment for the fabrication of nanoengineered, mixed transition metal oxide anode from inorganic domestic waste, for lithium-ion batteries
    (Springer, 2024) Ashraf, Humza ; Karahan, B. Deniz ; 0000-0002-7839-2222 ; Metalurji ve Malzeme Mühendisliği
    A novel method for the fabrication of nanoengineered, mixed transition metal oxide anode active material is proposed based on implementing liquid nitrogen treatment during the chemical precipitation process, for the first time in open literature. Such interference in the precipitation is believed to change the surface energy of the nuclei leading to differentiation in the growth process. To exemplify this hypothesis with an environmentally friendly approach, kitchen scourer pads, an existing waste, are used as a starting material instead of using a mixture of primary quality metals’ salts. Therefore, in this study, firstly, an optimization is realized to leach the scouring pad with 100% efficiency. Then, by applying a conventional chemical precipitation to this leachate at pH 5.5, Sample 1-P is produced. Herein, innovatively liquid nitrogen treatment is carried out during the chemical precipitation to produce Sample 2-P. Lastly, these precipitates (Samples 1-P, 2-P) are calcinated in the air to form mixed transition metal oxide powders: Samples 1 and 2, respectively. Structural, chemical, and morphological characterizations are carried out to examine the effect of liquid nitrogen treatment on the powders’ properties. To discuss the effect of nitrogen treatment on the electrochemical performances of the anode active materials (Sample 1 and Sample 2), galvanostatic tests are realized. The results show that Sample 2 demonstrates a higher 1st discharge capacity (1352 mAh/g) and retains 62% of its performance after 200 cycles when 50 mA/g current load is applied. Moreover, this electrode delivers around 500 mAh/g at 1 A/g current load. The remarkable cycle performance of Sample 2 is believed to be related to the superior chemical, structural, and physical properties of the electrode active material.
  • Öge
    Design and nonlinear dynamic response of a steel stack
    (Springer, 2024) Vatansever, Cüneyt ; Çayır, Haşim ; 0000-0002-9954-925X ; 0000-0001-8131-4703 ; İnşaat Mühendisliği
    Industrial stacks are built in order to reduce atmospheric pollution and release gases to the higher level of the atmosphere. Since they are high and slender structures, they are significantly affected by lateral forces, in particular, induced by winds and earthquakes. This paper aims to summarize the design principles for steel stacks given in the international standards, codes and specifications considering the evaluation of the results from the investigation on nonlinear dynamic response of a typical steel stack subjected to the earthquake. For this purpose, a typical self-supporting steel stack has been designed and its performance under earthquake and wind forces has been investigated in terms of the applied design principles, such as the displacement limit and the potential plastic deformations. The study is accomplished by using finite element models employing nonlinear time history and pushover analyses. The numerical results are presented particularly by considering the design principles used for the model. The results show that wind loads considered are more pronounced in the design of industrial steel stacks than earthquake especially in terms of limiting top displacement. The flue openings which reduce strength and lateral stiffness of the stack web is significantly effective in the lateral behavior of the stack. Moreover, the principles considered are found applicable for the design of such steel stacks. Based on the results from nonlinear time history analyses, no yielding and plastic deformation are detected along the stack.
  • Öge
    Development of biodegradable poly(butylene succinate) based nanofibrous webs via solution-blow spinning technology for N95 respiratory filters
    (Springer, 2024) Pakolpakçil, Ayben ; 0000-0002-6981-4980 ; Tekstil Mühendisliği
    As a result of the COVID-19 outbreak, millions of people are wearing face masks (including disposable surgical face masks), and many used masks, particularly disposable masks, are entering the environment and increasing pollution. The applicability of nanofibers in the field of filtration is considerable, and it has replaced environmentally friendly materials in research in this area. Solution-blown spinning (SBS) is an efficient and straightforward method for creating micro and nanofibers that allow quick fiber deposition on any substrate. Poly(butylene succinate) (PBS) is an environmentally safe biopolymer with unique properties, such as processability and flexibility, that has piqued the interest of industry and researchers. Hence, an eco-friendly air filter based on PBS nanofibers was fabricated using SBS. This solution-blown spun PBS filter was demonstrated as an air filter for the first time. The findings demonstrated that a weight of around 19.3 g/m2 PBS webs with a mean diameter of 199 nm was adequate to produce a filtering performance of 95.26% with a pressure drop of 251 Pa at a flow rate of 85 L/min. The fast and economic features of the SBS process, as well as the environmentally friendly nature of the PBS polymer, may be a considerable contribution to the development of green filters.
  • Öge
    Discovering the perception differences of stakeholders on the sustainable and innovative stormwater management practices
    (Springer, 2024) Ekmekçioğlu, Ömer ; 0000-0002-7144-2338 ; Afet ve Acil Durum Yönetimi Anabilim Dalı
    The overarching aim of the present work is to explore the perception differences of stakeholders, i.e., municipalities (MN), water administrations (WS), non-governmental organizations (NGO), and universities (UN), playing vital roles in the decision mechanisms regarding one of the sustainable flood mitigation techniques, i.e., low impact development (LID) practices. As being rewarding alternative to conventional drainage techniques, four different LID strategies, i.e., green roof (GR), bioretention cells (BC), permeable pavement (PP), and infiltration trench (IT), and three of their combinations were adopted to the densely urbanized Ayamama River basin, Istanbul, Turkey. The performances of the LIDs were comprehensively evaluated based on three pillars of sustainability (i.e., social, economic, and environmental) using a hybrid multi-criteria decision-making (MCDM) framework containing the implementation of fuzzy analytical hierarchy process (fuzzy AHP) and the VIKOR (VIse KriterijumsaOptimiz acija I Kompromisno Resenje) for finding the weights of constraining criteria and prioritizing the LID scenarios, respectively. The major outcomes of this research showed that experts from MN, WS, and UN put forward the environmental dimension of sustainability, whereas respondents from NGO concentrated on the social aspect. Furthermore, MN and WS highlighted initial investment cost as the most determining criterion in optimal LID selection. On the other hand, criteria weights regarding the judgments of the experts attended from NGO revealed the significance of community resistance in specifying the optimal LID practices, while aesthetic appearance was the major concern of the academia. Hence, the present study, as an initial attempt, enabled critical standpoints for discovering perceptions of stakeholders.
  • Öge
    Effect of spray drying on physicochemical stability and antioxidant capacity of rosa pimpinellifolia fruit extract-loaded liposomes conjugated with chitosan or whey protein during in vitro digestion
    (Springer, 2024) Kasapoğlu, Kadriye Nur ; Gültekin-Özgüven, Mine ; Kruger, Johanita ; Frank, Jan ; Bayramoğlu, Pelin ; Barla-Demirkoz, Aslı ; Özçelik, Beraat ; 0000-0001-6070-4948 ; 0000-0002-2073-8075 ; 0000-0002-1810-8154 ; Gıda Mühendisliği
    Spray drying is a well-established, energy efficient, and scalable process widely used in the food industry, however it may lead to thermal degradation of susceptible compounds, such as (poly)phenols, resulting in biological activity loss to some extent. In this study, we aimed to improve the physicochemical stability and bioaccessibility of (poly)phenols from Rosa pimpinellifolia fruit extract (Rosa extract) loaded in liposomes by generating solid particles via spray drying. Liposomes were conjugated with chitosan (Ch) and whey protein (Wp) to optimize the biopolymer concentrations by monitoring mean particle diameter, polydispersity index, and surface charge. The mean diameter of liposomes ranged between 135 and 210 nm upon optimal addition of Ch (0.4%, w/v) and Wp (4.0%, w/v) which also increased the entrapment efficiency of (poly)phenols from 74.2 to 77.8% and 79.1%, respectively. After spray drying, about 65–76% of the antioxidant capacity were retained in biopolymer-conjugated liposomes (Ch or Wp) while the retention rate was 48% in only spray-dried extract (Rosa extract powder). Compared to unencapsulated Rosa extract, spray drying (Rosa extract powder) and conjugation with Ch (Ch-Lip powder) or Wp (Wp-Lip powder) significantly increased the bioaccessibility of (poly)phenols and preserved their antioxidant capacity. Based on the findings of this study, Ch- or Wp-conjugation of liposomes prior to spray drying could improve physicochemical stability and protect (poly)phenols loaded in liposomes against processing stress and passage through the digestive tract. Further in vitro and in vivo investigations on a variety of bioactive compounds may draw more attention to their potential as functional foods.
  • Öge
    Effects of particle damper design parameters on the damping performance of laser powder bed fused structures
    (Springer, 2024) Özçevik, Birol ; Söylemez, Emrecan ; Bediz, Bekir ; Şimşek, Uğur ; 0000-0003-4003-9287 ; 0000-0003-4827-2606 ; 0000-0002-7925-8228 ; 0000-0002-4405-5420 ; Mechanical Engineering
    Particle dampers (PD), a passive damping technology, absorb energy from particle-particle and particle-cell wall interactions originating from friction and collision. PDs offer advantages such as design simplicity, low cost, applicability in harsh conditions, and flexibility to be used in a wide frequency band range. Additive manufacturing, specifically the powder bed fusion process, can fabricate structures with integrated PDs in a single printing process, eliminating the need to implement external dampers. However, the dynamic behavior of PDs must be determined to utilize their full potential. In this study, we examined 16 cases of integrated PDs by varying specific parameters including size, number, and locations on the structure to understand the effects of these parameters on the dynamic behavior of the first and second modes of the structure. Modal tests were conducted on additively manufactured samples to extract frequency response functions and calculate modal parameters (natural frequency and damping ratio) using the rational fraction polynomial method, studying the effects of PDs. The results showed that the damping performance of the parts was increased by a factor of up to 10 using body-integrated PDs compared with the fully fused specimen. The effectiveness of body-integrated PDs was shown to be strongly dependent on their volume and location. For instance, the damping generally increased as the volume fraction increased, which also reduced the total weight of the specimens by up to 60 g. Furthermore, the damping performance significantly increased for a specific mode when the PDs were located near the maximum displacement regions.
  • Öge
    Elemental composition of household dusts extracted in simulated body fluids and their impact on culturable pathogenic bacteria responses
    (Springer, 2024) Baysal, Aslı ; Zora, Sevilay ; Saygın, Hasan ; 0000-0002-0178-7808 ; 0000-0002-6534-0538 ; 0000-0003-2479-7635 ; Kimya Bölümü
    In the last decade, a great deal of research has focused on the determination of potential toxic elements by total concentration and identification the microorganisms in dust. However, determining bio-relevant (e.g., inhalable) forms of elements instead of total contents in acids is necessary for human health. Moreover, examination of the behavior of microorganism under these bio-relevant conditions and revealing the interaction between elements and pathogens is vital and necessary for deeper understanding. However, previous studies have ignored these topics. Therefore, the present study aimed to (i) investigate elements in household dusts extracted in simulated lung fluids, (ii) examine the total concentration of culturable bacteria and their biochemical responses with exposure to bio-fractions of household dusts, and (iii) assess their relations and risks using the model approaches by inhalation. Here, settled dusts were collected in 25 houses, and extracted in four simulated body fluids to determine bio-fractions of elements. Moreover, total count of potentially pathogenic and heterotrophic bacteria, and four clinically important culturable pathogens were incubated in the presence of household-dusts extracted in simulated body fluids. The activity, biofilm, biochemical and oxidative responses of pathogens were measured following household-dust exposures. Afterward, the relationship between elements and pathogen responses were evaluated, and model and derived approaches were used for risk assessments of elements and pathogens. The higher daily intake of elements obtained in artificial lysosomal fluid fraction of household dust mimicking the inflammatory condition compared to other body fluids. Moreover, bacterial responses were mainly influenced from bio-fractions of household dusts and their elemental contents.
  • Öge
    Encapsulated phenolic compounds : clinical efficacy of a novel delivery method
    (Springer, 2024) Özkan, Gülay ; Ceyhan, Tuğçe ; Çatalkaya, Gizem ; Rajan, Logesh ; Ullah, Hammad ; Daglia, Maria ; Çapanoğlu, Esra ; 0000-0003-0335-9433 ; Gıda Mühendisliği Bölümü
    Encapsulation is a drug or food ingredient loaded-delivery system that entraps active components, protecting them from decomposition/degradation throughout the processing and storage stages and facilitates their delivery to the target tissue/organ, improving their bioactivities. The application of this technology is expanding gradually from pharmaceuticals to the food industry, since dietary bioactive ingredients, including polyphenols, are susceptible to environmental and/or gastrointestinal conditions. Polyphenols are the largest group of plants' secondary metabolites, with a wide range of biological effects. Literature data have indicated their potential in the prevention of several disorders and pathologies, ranging from simpler allergic conditions to more complex metabolic syndrome and cardiovascular and neurodegenerative diseases. Despite the promising health effects in preclinical studies, the clinical use of dietary polyphenols is still very limited due to their low bioaccessibility and/or bioavailability. Encapsulation can be successfully employed in the development of polyphenol-based functional foods, which may improve their bioaccessibility and/or bioavailability. Moreover, encapsulation can also aid in the targeted delivery of polyphenols and may prevent any possible adverse events. For the encapsulation of bioactive ingredients, several techniques are applied such as emulsion phase separation, emulsification/internal gelation, film formation, spray drying, spray-bed-drying, fluid-bed coating, spray-chilling, spray-cooling, and melt injection. The present review aims to throw light on the existing literature highlighting the possibility and clinical benefits of encapsulated polyphenols in health and disease. However, the clinical data is still very scarce and randomized clinical trials are needed before any conclusion is drawn.