Mathematics / Matematik

Permanent URI for this collectionhttps://hdl.handle.net/11147/8

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  • Article
    Unique decompositions into regular ideals for Marot rings
    (Taylor & Francis, 2022) Ay Saylam, Başak; Gürbüz, Ezgi
    Let R be a commutative ring. We say that R has the unique decomposition into regular ideals (UDRI) property if, for any R-module which decomposes into a finite direct sum of regular ideals, this decomposition is unique up to the order and isomorphism class of the regular ideals. In this paper, we will prove some preliminary results for Marot rings whose regular ideals are finitely generated and give a necessary and sufficient condition for these rings to satisfy the UDRI property.
  • Article
    Citation - WoS: 2
    Citation - Scopus: 2
    On simple-injective modules
    (World Scientific Publishing, 2022) Alagöz, Yusuf; Benli Göral, Sinem; Büyükaşık, Engin
    For a right module M, we prove that M is simple-injective if and only if M is min-N-injective for every cyclic right module N. The rings whose simple-injective right modules are injective are exactly the right Artinian rings. A right Noetherian ring is right Artinian if and only if every cyclic simple-injective right module is injective. The ring is QF if and only if simple-injective right modules are projective. For a commutative Noetherian ring R, we prove that every finitely generated simple-injective R-module is projective if and only if R = A × B, where A is QF and B is hereditary. An abelian group is simple-injective if and only if its torsion part is injective. We show that the notions of simple-injective, strongly simple-injective, soc-injective and strongly soc-injective coincide over the ring of integers.
  • Article
    Citation - WoS: 1
    Citation - Scopus: 1
    Fatigue Life Prediction and Optimization of Gfrp Composites Based on Failure Tensor Polynomial in Fatigue Model With Exponential Fitting Approach
    (SAGE Publications, 2022) Güneş, Mehmet Deniz; İmamoğlu Karabaş, Neslişah; Deveci, Hamza Arda; Tanoğlu, Gamze; Tanoğlu, Metin
    In this study, a new fatigue life prediction and optimization strategy utilizing the Failure Tensor Polynomial in Fatigue (FTPF) model with exponential fitting and numerical bisection method for fiber reinforced polymer composites has been proposed. Within the experimental stage, glass/epoxy composite laminates with (Formula presented.), (Formula presented.), and (Formula presented.) lay-up configurations were fabricated, quasi-static and fatigue mechanical behavior of GFRP composites was characterized to be used in the FTPF model. The prediction capability of the FTPF model was tested based on the experimental data obtained for multidirectional laminates of various composite materials. Fatigue life prediction results of the glass/epoxy laminates were found to be better as compared to those for the linear fitting predictions. The results also indicated that the approach with exponential fitting provides better fatigue life predictions as compared to those obtained by linear fitting, especially for glass/epoxy laminates. Moreover, an optimization study using the proposed methodology for fatigue life advancement of the glass/epoxy laminates was performed by a powerful hybrid algorithm, PSA/GPSA. So, two optimization scenarios including various loading configurations were considered. The optimization results exhibited that the optimized stacking sequences having maximized fatigue life can be obtained in various loading cases. It was also revealed that the tension-compression loading and the loadings involving shear loads are critical for fatigue, and further improvement in fatigue life may be achieved by designing only symmetric lay-ups instead of symmetric-balanced and diversification of fiber angles to be used in the optimization.
  • Article
    Citation - WoS: 2
    Citation - Scopus: 3
    A Reliable Explicit Method To Approximate the General Type of the Kdv–burgers’ Equation
    (Springer, 2022) Korkut, Sıla Övgü; İmamoğlu Karabaş, Neslişah
    This study aims to propose a reliable, accurate, and efficient numerical approximation for a general compelling partial differential equation including nonlinearity (uδ∂u∂x), dissipation (∂2u∂x2), and dispersion (∂3u∂x3) which arises in many fields of engineering as well as applied sciences. The novel proposed method has been developed combining a kind of mesh-free method called the Taylor wavelet method with the Euler method. The convergence result of the method has been presented theoretically. Moreover, the validation and applicability of the method have been also confirmed computationally on benchmark problems such as KdV–Burgers’ equation and modified-KdV equation. The numerical results have been compared both to the exact solution and to those in the existing literature. All presented figures and tables guarantee that the proposed method is highly accurate, efficient, and compatible with the nature of the specified equation physically. Furthermore, the recorded errors are evidence that the proposed method is the best approximation compared to those in the existing methods.