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  1. Article ; Online: Effects of testing speed on the tensile and mode I fracture behavior of specimens printed through the Fused Deposition Modeling technique.

    Zhan, Jiangtao / Cai, Jie / Hasani, Reza

    Scientific reports

    2024  Volume 14, Issue 1, Page(s) 3960

    Abstract: Additive Manufacturing (AM) processes are known as revolutionary manufacturing processes that fabricate a part using a 3D model layer upon layer. These techniques gained more attention from various industries due to their advantages like low waste ... ...

    Abstract Additive Manufacturing (AM) processes are known as revolutionary manufacturing processes that fabricate a part using a 3D model layer upon layer. These techniques gained more attention from various industries due to their advantages like low waste material. Also, these processes can produce any part with high degrees of complexity in a short period of time. The Fused Deposition Modeling (FDM) process is a material extrusion-based technique which works by extruding a fine molten polymeric filament through a heated nozzle on the heated platform named printer bed. In this method, some important manufacturing parameters play a crucial role in controlling the mechanical properties and quality of the final fabricated part. However, all printed specimens through the FDM process should be tested based on the standards under some critical circumstances. Thus, in the current research paper, five and three test speeds are considered in tensile and fracture testing procedures, respectively to evaluate how these speeds can affect the mechanical and mode I fracture properties. Also, as the FDM specimens present elastic-plastic behavior, the critical value of J-integral is assumed as a fracture assessment and calculated from the finite element analysis. Among the mechanical properties, ultimate tensile strength is affected significantly by the test speed. For instance, the ultimate tensile strength of FDM specimens is 39.02, 38.58, 42.33, 48.09, and 52.11 for test speeds of 2, 4, 6, 8, and 10 mm/min, respectively. But vice-versa results are detected for the mode I fracture behavior and corresponding values of J for the FDM-PLA specimens. Finally, experimental and numerical results together with comprehensive discussions about the considered speeds and obtained results are reported.
    Language English
    Publishing date 2024-02-17
    Publishing country England
    Document type Journal Article
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-024-54780-9
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Comparison of epidemiologic factors and eye manifestations of twin children with controls.

    Rajavi, Zhale / Sabbaghi, Hamideh / Hasani, Reza / Behradfar, Narges / Abdi, Saeid / Kheiri, Bahareh / Haseli-Mofrad, Azadeh

    BMC ophthalmology

    2023  Volume 23, Issue 1, Page(s) 246

    Abstract: Purpose: The present study was aimed to compare the epidemiological and ocular findings of twin children in comparison with non- twin age matched individuals as their control.: Methods: In this cross sectional study, a total of 90 twins (180 cases) ... ...

    Abstract Purpose: The present study was aimed to compare the epidemiological and ocular findings of twin children in comparison with non- twin age matched individuals as their control.
    Methods: In this cross sectional study, a total of 90 twins (180 cases) were compared with 182 non- twin matched children. All the study participants were examined by a comprehensive ophthalmic examination including measurement of the best corrected visual acuity (BCVA), cycloplegic refraction, ocular deviation, strabismus as well as the anterior and posterior ophthalmic examinations. Demographic information of children were collected by using an organized questionnaire. Monozygotic twins were considered if there were similarity of their phenotypic characteristics and gender, otherwise the twins were considered as dizygotic.
    Results: The mirror- image twins (MIT) was defined according to the laterality of symmetrical ocular characteristics of twins. In this study, the mean age of the study participants was 7.08±4.42 and 7.58±3.99 years in twins and non-twins groups, respectively (P=0.253). Among the twins, 27 (30%) were monozygotic. Refractive form of MIT was seen in 5 twins (2.8%). The spherical refractive error was more hyperopic in twins compared to non- twins (P=0.041). BCVA in the twin group (0.07±0.16LogMAR) was significantly worse than non-twins (0.03±0.08LogMAR, P < 0.001) and higher percentage of them were amblyopic (37.2% versus 10.4%, P=0.005). Twin and controls had strabismus in 17.2% and 1.6%, respectively (P < 0.001). Regarding the comparison between mono- and dizygotic twins, more significant percentage of monozygotic twins had amblyopia (P=0.004) and strabismus (P=0.047). Multivariate analysis showed significant correlation among low gestational age and female gender, low birth weight and seizure.
    Conclusion: Female sex, less gestational age, low birth weight, amblyopia and strabismus were significantly higher in twins. Therefore, it is important to check their refractive error, amblyopia and strabismus to prevent their further complications.
    MeSH term(s) Child ; Child, Preschool ; Female ; Humans ; Amblyopia/etiology ; Cross-Sectional Studies ; Epidemiologic Factors ; Refractive Errors/epidemiology ; Refractive Errors/complications ; Strabismus/epidemiology ; Twins, Monozygotic ; Visual Acuity ; Male
    Language English
    Publishing date 2023-06-01
    Publishing country England
    Document type Journal Article ; Twin Study
    ZDB-ID 2050436-6
    ISSN 1471-2415 ; 1471-2415
    ISSN (online) 1471-2415
    ISSN 1471-2415
    DOI 10.1186/s12886-023-02983-5
    Database MEDical Literature Analysis and Retrieval System OnLINE

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