Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Subject: search.filters.subject.PorosityWoS Q: search.filters.wosQuartile.Q3

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Now showing 1 - 5 of 5
  • Article
    Citation - WoS: 1
    Citation - Scopus: 1
    Synthesis of Pristine Chitosan Foams with Enhanced Pore Structure, Surface Area, and Mechanical Strength for Tissue Engineering Applications
    (Iop Publishing Ltd, 2025) Polat, M.; Cropper, Chelsea; Ozdamar, A. B.; Polat, H.
    With its excellent biocompatibility, biodegradability, and antimicrobial activity, chitosan is a promising scaffold material for hard-tissue engineering. Yet, pristine chitosan foams typically lack the strength and porosity required for such use. Here we present a simple emulsion-templating approach to fabricate pristine chitosan foams with optimized strength and porosity. Sodium dodecyl sulfate (SDS), a widely used biocompatible anionic surfactant, was employed at trace levels to aid polymerization. The foams display a dual-scale pore morphology. Cavities of 150-300 mu m are separated by around 50 mu m thick chitosan walls containing large interconnecting openings. The walls are further populated with meso- and macropores of 50-500 nm. This architecture should support cell attachment and growth, facilitate proliferation, and enhance nutrient transport and metabolic exchange. The structure yields high surface area (up to 10 m2 g-1). Mechanically, the thick-walled cavities impart both elastic recovery and high compressive resistance (255 kPa at 40% strain from foams polymerized with 4% chitosan). A preliminary drug-release study using vancomycin confirmed excellent loading and sustained release.
  • Article
    Performance of Sheet Pile Walls With Rubber-Modified Backfill
    (Springer, 2025) Ecemis, Nurhan; Kadekeshova, Kuralay; Khlaif, Ali Hamid
    This study investigates the behavior of clean sand and sand-rubber mixtures used as backfill materials behind sheet pile walls under vertical loads. Physical model experiments were conducted to assess lateral displacement and pressure for backfills containing 10% granulated rubber (2.5-5 mm) under both dry and saturated conditions, and across varying backfill inclination angles. To complement the experiments, discrete element method (DEM) simulations were performed to capture the micromechanical behavior of sand-rubber mixtures, enabling analysis of particle-scale interactions. Material stiffness and friction parameters were calibrated through direct shear tests to ensure computational efficiency and accurate representation. Comparative analyses were conducted between the DEM simulations and the physical sheet pile tests across various sand-rubber backfill configurations. The results suggest that sand-rubber mixtures offer a practical and sustainable alternative for backfill applications, improving both mechanical performance and pressure mitigation. Furthermore, force chain development and deformation patterns were thoroughly examined to understand the role of micro parameters; such as particle contact behavior, porosity, internal friction, and stiffness of the rubber-sand composite backfill in reducing active earth pressure against sheet pile walls.
  • Article
    Citation - WoS: 8
    Citation - Scopus: 8
    Pore Connectivity Effects on the Internal Surface Electric Charge of Mesoporous Silica
    (Springer, 2019) Şen, Tümcan; Barışık, Murat
    Nano-scale confinements within mesoporous systems develop overlapping electric double layers (EDL) such that the existing theoretical models cannot predict the electric potential distributions and resulting surface charges. In addition, ionic conditions undergo local variation through connections between the pore voids and pore throats. For the first time in literature, we studied the charging behavior of mesoporous silica in terms of the pore to throat size ratio (R-pt) to characterize the pore connectivity effects, in addition to porosity (epsilon) and pore size (H). Both local and average surface charge densities inside mesoporous silica were examined by varying these parameters systematically. Results showed that the magnitude of surface charge density decreased with increasing EDL overlap and decreasing connectivity effects. We formulized this behavior and developed an extended model to predict mesoporous silica's internal charge as a function of porosity, pore size, and pore to throat size ratio.
  • Article
    Citation - WoS: 3
    Citation - Scopus: 3
    Feasible Packing of Granular Materials in Discrete-Element Modelling of Cone-Penetration Testing
    (Taylor and Francis Ltd., 2018) Ecemiş, Nurhan; Bakunowicz, Paulina
    This paper explores how the discrete-element method (DEM) was found to play an increasingly important role in cone penetration test (CPT) where continuum-mechanics-based analysis tools are insufficient. We investigated several crucial features of CPT simulations in the two-dimensional DEM. First, the microparameters (stiffness and friction) of discrete material tailored to mimic clean, saturated sand, which is used in cone-penetration tests, were calibrated by curve-fitting drained triaxial tests. Then, three series of cone-penetration simulations were conducted to explore (1) top boundary conditions, (2) reasonable size of discrete particles at different initial porosities, and (3) limit initial porosity of the model for a balance between accurate representation and computational efficiency. Further, we compared the cone-penetration resistance obtained in the laboratory and numerical simulations for the range of relative densities.
  • Article
    Citation - WoS: 36
    Citation - Scopus: 38
    Investigation on Glassy Skin Formation of Porous Polystyrene Fibers Electrospun From Dmf
    (BME-PT, 2010) Demir, Mustafa Muammer
    Micrometer and submicrometer diameter of polystyrene (PS) fibers were electrospun from various dimethyl formamide (DMF) solutions at different weight fractions under 35% relative humidity. Increasing polymer fraction in the solution results in a gradual morphological transition from beads-with-incipient to bead-free fibers and also increases the diameter. The formation of uniform glassy skin presumably due to radial capillary flow within the liquid jet was confirmed by scanning electron microscope. The thickness of the skin varies with the weight fraction of PS; therefore, it was normalized with respect to average fiber diameter (AFD). The skin gets thinner as the weight fraction of PS increases. In addition, the fibers exhibit highly porous internal structure and smooth surface along with slight porosity. The development of porosity is attributed to liquid-liquid phase separation of water molecules in atmospheric moisture and DMF.