Browsing by Subject "tensile strength"

Now showing 1 - 9 of 9
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    A dynamic uniaxial wide strip tensile testing of two geotextiles in isolation
    (Elsevier Sci Ltd, 1999) Güler E.; Biro M.S.T.
    Geotextiles must sustain static, and often dynamic loads, during the lifetime of the structure in which they are placed. A test apparatus is constructed to examine the tensile behaviour and performance of two different low strength nonwoven geotextiles under dynamic loading. The apparatus is designed as a vertical uniaxial dynamic tensile testing equipment for testing geotextiles in isolation. The nonwoven geotextiles examined both performed well under rigorous test conditions. Charts and tables showing the measurements taken during tests and the results of these observations are presented.; Geotextiles must sustain static, and often dynamic loads, during the lifetime of the structure in which they are placed. A test apparatus is constructed to examine the tensile behaviour and performance of two different low strength nonwoven geotextiles under dynamic loading. The apparatus is designed as a vertical uniaxial dynamic tensile testing equipment for testing geotextiles in isolation. The nonwoven geotextiles examined both performed well under rigorous test conditions. Charts and tables showing the measurements taken during tests and the results of these observations are presented.
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    A calculation of stress distribution in metal-porcelain crowns by using three-dimensional finite element method
    (2002) Aykul H.; Toparli M.; Dalkiz M.
    The objective of this study was to calculate stress distribution in a maxillary second premolar tooth which occurred by the mastication force. The tooth model was crowned with Au-Pd alloy, Ni-Cr alloy and porcelain. A load of 450 N, at an angle of 45° to the longitudinal axis was applied on the occlusal margin of the crown tooth. The tooth was assumed isotropic, homogenous, elastic and unsymmetrical. This numerical study was carried out using three-dimensional finite element models and calculation programs were prepared by the authors using FORTRAN 77. The distribution of compressive, tensile and shear stress were plotted for the dentine, dentine-metal and metal-porcelain interfaces. The highest stress values were observed when Ni-Cr alloy and porcelain was used. © 2002 Blackwell Science Ltd.
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    Hardness and yield strength of dentin from simulated nano-indentation tests
    (2005) Toparli M.; Koksal N.S.
    The finite element method (FEM) is applied for studying the hardness (H) and yield strength (Y) of dentin subjected to a nano-indentation process. The nano-indentation experiments were simulated with the ABAQUS finite element software package. This test, performed with a spherical indenter, was simulated by axisymmetric finite element analysis. The load versus displacement was calculated during loading-unloading sequence for different elastic modulus (E) and yield strength. Hardness and maximum principal compressive and tensile stresses were plotted for different elastic modulus depending on yield strength. The dentin was assumed to be isotropic, homogenous and elasto-plastic. The theoretical results outlined in this study were compared with the experimental works reported in the literature and then hardness and yield strength of dentin was estimated. © 2004 Elsevier Ireland Ltd. All rights reserved.
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    Comparison of effects of different screw materials in the triangle fixation of femoral neck fractures
    (Springer New York LLC, 2017) Gok K.; Inal S.; Gok A.; Gulbandilar E.
    Abstract: In this study, biomechanical behaviors of three different screw materials (stainless steel, titanium and cobalt–chromium) have analyzed to fix with triangle fixation under axial loading in femoral neck fracture and which material is best has been investigated. Point cloud obtained after scanning the human femoral model with the three dimensional (3D) scanner and this point cloud has been converted to 3D femoral model by Geomagic Studio software. Femoral neck fracture was modeled by SolidWorks software for only triangle configuration and computer-aided numerical analyses of three different materials have been carried out by AnsysWorkbench finite element analysis (FEA) software. The loading, boundary conditions and material properties have prepared for FEA and Von-Misses stress values on upper and lower proximity of the femur and screws have been calculated. At the end of numerical analyses, the best advantageous screw material has calculated as titanium because it creates minimum stress at the upper and lower proximity of the fracture line. Graphical Abstract: [InlineMediaObject not available: see fulltext.] © 2017, Springer Science+Business Media New York.
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    Role of a combination dietary supplement containing mucopolysaccharides, vitamin C, and collagen on tendon healing in rats
    (Turkish Association of Orthopaedics and Traumatology, 2018) Gemalmaz H.C.; Sarıyılmaz K.; Ozkunt O.; Gurgen S.G.; Silay S.
    Objective: The aim of this study was to investigate the effect of mucopolysaccharide, vitamin C, and collagen supplementation on the healing of Achilles tendon in rats. Methods: Sixteen rats were separated into 2 groups. Both Achilles tendons of all rats were transected 5 mm above the insertion and repaired using a Kessler suture. After the surgical repair, the study group received the daily recommended amount of the supplement by gastric gavage, while the control group received a placebo. At the end of the third week, the animals were sacrificed. The biomechanical properties of the groups were compared with ultimate tensile strength and stiffness tests. The biological properties of the 2 groups were assessed with a histomorphometric comparison to determine the amount of collagen type I (COL1), proliferating cell nuclear antigen (PCNA), and transforming growth factor β1 (TGF-β1) expression in 3 different tissue subgroups (collagen matrix, tenocytes, and endotenon fibroblasts). Results: Analysis of histomorphometric results revealed that the rats receiving dietary supplements demonstrated a significant increase in PCNA (mean value of 86 in the control group and 168.85 in the trial group; p < 0.05) and TGF-β1 (mean value of 87.57 in the control group and 161.85 in the trial group; p < 0.05) in the endotenon fibroblasts of the repair site. However, there was no difference between the groups in PCNA or TGF-β1 when the collagen matrix and the tenocytes of the repair site were examined. Furthermore, no significant difference could be found between groups in COL1 in any of the 3 tissue subgroups (collagen matrix, tenocytes, and endotenon fibroblasts). The statistical analysis also indicated that the rats receiving supplements did not demonstrate a significant increase in the ultimate tendon tensile strength or stiffness. Conclusion: The results of this study revealed no advantage to the oral administration of the trial supplement in collagen synthesis or biomechanical properties in rats after 3 weeks using the presented study design. However, the increased expression of PCNA and TGFβ1 seen in the endotenon fibroblasts of the repair site might play a role in the continuum of tendon healing. © 2018 Turkish Association of Orthopaedics and Traumatology
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    Investigating the effect of decontaminants on microbiological and chemical properties of rainbow trouts
    (TUBITAK, 2021) Dikici A.; Özpolat E.; Bozatli S.B.; Koluman A.; Patir B.; Çalicioğlu M.
    This study was designed to determine the effect of decontamination on the shelf life of whole rainbow trouts. For this purpose 0.5% cetylpyridinium chloride (CPC), 10% trisodium phosphate (TSP), 2.5% acetic acid (AA), 2.5% lactic acid (LA), 1200 ppm acidified sodium chloride (ASC) and control (tap water) were used as decontaminants. After the decontamination process, the samples were stored in cold storage and subjected to microbiological and chemical analyzes on days 0, 3, 6, 9, 12 and 15. Mesophilic bacteria, psychrophilic bacteria, lactic acid bacteria, Pseudomonas spp., Enterobacteriaceae and coliform bacteria were enumerated for the evaluation of microbiological quality, whereas pH, total volatile alkaline nitrogen (TVB-N), thiobarbituric acid (TBA) were determined for the evaluation of the chemical quality of fish samples. The study was repeated 3 times and 6 fish were used in each group corresponding to 108 fish in total. Microbiological samples were evaluated with a modification in USDA/FSIS chicken carcass method. The data of microbiological analysis showed that decontamination provided a significant improvement on the microbiological quality and the decontaminants used in this study extended the microbiological shelf life of rainbow trout. However, acidic decontaminants and TSP caused some changes in the physical properties of rainbow trouts. On the other hand, the use of CPC extended the shelf life of rainbow trouts without adversely affecting the texture. The microbiological sampling protocol used in this study was proved to be easier to apply and gave coherent results. © TÜBİTAK
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    Effect of gamma irradiation on the thermal and mechanical behaviour of polypropylene and polyethylene blends
    (Elsevier Ltd, 2022) Sirin M.; Zeybek M.S.; Sirin K.; Abali Y.
    This study investigates the effect of radiation over polypropylene and polyethylene blends samples with different weight ratios. 10, 30, 50, 70, and 100 kGy doses of radiation were applied from the 60Co source on the polymer blends obtained by mixing polypropylene (PP) and polyethylene (LDPE) samples with different molecular weights in different ratios by weight. Melting flow rates (MFI), hardness, tensile strength at yield, tensile strength at break, elongation at break, differential scanning calorimetry (DSC), and thermogravimetric analysis (TG) of the samples were examined. When melting flow index of the samples was examined, it was determined that there was a significant increase in the speed of melting flow in connection with increasing radiation doses. When the mechanical analyses of the samples were examined, there was a significant decrease in tensile strength at yield, tensile strength at break, and elongation at break values. Particularly, as the samples with 100 kGy dose had deformation, there was no reading for these values. When DSC analysis of the samples was examined, depending on the increasing radiation dose, there was a decrease in melting temperature Tm, crystallization temperature Tc, melting enthalpy ΔHf, crystallization enthalpy ΔHc and the rate of crystallization Xc values. It was observed that there was a mass loss against heat in TG analysis of samples. © 2022
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    Novel starch–tungsten (VI) oxide biocomposites: Preparation, characterization, and comparisons between experimental and theoretical photon attenuation coefficients
    (Elsevier B.V., 2024) Körpınar B.; Öztürk B.C.; Çam N.F.; Akat H.
    This study synthesized biocomposites containing starch and WO3 at varying ratios of 10 %, 20 %, 30 %, 40 %, and 50 % and assessed their thermal and radiation-shielding properties. These biocomposites were characterized using Fourier-transform infrared spectroscopy, X-ray diffraction (XRD) analysis, particle-size distribution assessments, scanning electron microscopy–energy dispersive X-ray spectroscopy, and thermogravimetric analysis–differential thermogravimetry measurements. Furthermore, the linear attenuation coefficients of the biocomposites were experimentally measured using an NaI(Tl) gamma spectrometry system and theoretically computed using XCOM and GAMOS simulations for comparisons. The XRD and particle-size distribution profiles of the WO3.2H2O powder, respectively, demonstrated evident diffraction peaks and favorable pore-size distributions. Morphological characterizations revealed that the WO3 particles were homogeneously dispersed throughout the starch matrix without any agglomeration. Comparisons of the thermal degradation rates revealed that the pure starch and starch +50%WO3 biocomposite began decomposing at approximately 200°Cand 300 °C, respectively, indicating that increasing WO3 proportions enhanced thermal stability. Furthermore, the starch +50%WO3 biocomposite demonstrated the highest experimental linear attenuation coefficient, with a value of 0.2510 ± 0.0848 cm−1 at a gamma energy of 662 keV. Meanwhile, XCOM and GAMOS simulations revealed theoretical attenuation coefficients of 0.1229 and 0.1213 cm−1 for pure starch and 0.2202 cm−1 and 0.2178 cm−1 for the starch +50%WO3 biocomposite at 662 keV, respectively. © 2024 Elsevier B.V.
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    Methyl cellulose/okra mucilage composite films, functionalized with Hypericum perforatum oil and gentamicin, as a potential wound dressing
    (Elsevier B.V., 2024) Coban S.N.; Polatoglu I.; Eroglu E.
    There is a growing demand for the development of functional wound dressings enriched with bioactive natural compounds to improve the quality of life of the population by accelerating the healing process of chronic wounds. In this regard, a functional composite film of okra mucilage (OM) and methylcellulose (MC) incorporated with Hypericum perforatum oil (Hp) and gentamicin (G) was prepared and characterized as a wound dressing. Increasing Hp resulted in improved film properties with a more porous structure, higher WVTR, and lower surface hydrophobicity. Furthermore, incorporating Hp into OM:MC films led to increased elongation at the break while reducing the tensile strength of the films. The highest values of total antioxidant capacity (1.09–1.16 mM trolox equivalent) and total phenolic content (13.76–16.94 μg GA equivalent mL−1) were measured in the composite films containing the highest Hp concentration (1.5 %). In addition, OM:MC/HpG composite films exhibited significant antibacterial activity against both E. coli and S. aureus and prevented the transmission of these bacteria through the films. Hp incorporation reduced the cytotoxic effects of OM:MC films on BJ cells and increased the wound closure rate in vitro. In conclusion, the developed OM:MC/HpG composite film can be a promising candidate as a novel wound dressing with its superior properties. © 2023