Mudanya University Institutional Academic Archive System
Mudanya University's Dspace system is a platform that digitally stores and opens academic studies. Academic content such as articles, presentations, theses, books, and reports are included here. Dspace@Mudanya provides easy access, making it a valuable resource for researchers and students. It serves as a digital archive for Mudanya University's academic outputs, facilitates access to scientific information and supports its sharing. For more information and assistance, please contact us.
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Recent Submissions
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Conversion Bariatric Surgery, Ketogenic Diet, and Intermittent Fasting in Bariatric Surgery Patients with Recurrent Weight Gain: a Prospective Randomized Controlled Trial
(Springer, 2026-04) Şen, Seher; Erdem, Nihal Zekiye; Durak, Doğukan; 409851
Background
Recurrent weight gain (RWG) after metabolic and bariatric surgery (MBS) increases the need for alternative treatment strategies. This study evaluated the effects of conversion bariatric surgery (CBS), very low-calorie ketogenic diet (VLCKD), and time-restricted intermittent fasting (TRIF) on anthropometric measurements, biochemical parameters, and dietary habits in patients who experienced suboptimal clinical response (SCR) or RWG after bariatric surgery.
Methods
This study included 56 patients, allocated to four groups (CBS, VLCKD, TRIF, and control; n = 14 each). Weight, waist-hip measurements, body composition, glycemic/lipid profile, and serum levels of specific vitamins and minerals were assessed at baseline and at week 6. Energy and nutrient intakes were calculated using BeBiS-9.
Results
Data were analyzed with SPSS 22.0. The percentages of total and excess weight loss differed significantly among the groups (p < 0.001), with CBS (9.07–28.5%), VLCKD (9.12–31.85%), TRIF (5.09–14.97%), and control (0.97–3.40%). Additionally, the pre- and post-intervention differences in fasting insulin, HOMA-IR, HbA1c, cholesterol, LDL-C, triglyceride, and uric acid levels varied significantly among the groups. VLCKD showed a more prominent effect on glycemic parameters, whereas CBS had a more beneficial impact on the lipid profile. In intervention groups, daily energy, carbohydrate and fat intake (g/day) decreased; protein percentages increased; the frequency of consumption of energy-dense foods decreased; and healthy food preferences increased.
Conclusions
Consequently, clinically significant improvements in weight management and metabolic parameters were observed in CBS, VLCKD, and TRIF groups under multidisciplinary team follow-up. These findings suggest that dietitian-led VLCKD and TRIF interventions may be considered as alternative treatment options before deciding on CBS.
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Analytical ETBDW Formulation for Electromagnetic Scattering by Circular Apertures on PMC Surfaces
(Springer, 2025-12) Altınel, Mustafa; Yalçın, Uğur; 414019
This study presents and validates a uniform analytical formulation for electromagnetic diffraction from circular apertures on perfect magnetic conductor (PMC) surfaces using the extended boundary diffraction wave (ETBDW) theory. The proposed PMC–ETBDW model incorporates an in-phase reflection coefficient (
= +1) within the boundary kernel, producing a physically continuous and energy-conserving representation of diffracted fields across illuminated, transition, and shadow regions. Expressed through detour parameters and Fresnel-type transition functions, the formulation eliminates phase discontinuities and maintains amplitude normalization consistent with theoretical energy conservation. Numerical evaluations performed for representative aperture radii (a = λ–3λ) and observation distances (r = 3λ–9λ) confirmed the expected 1/r amplitude decay, smooth Fresnel–Fraunhofer transitions, and constructive interference associated with magnetic reflection. Comparative analyses with PEC and opaque boundaries verified that in-phase magnetic reflection enhances on-axis field intensity and preserves phase continuity near the shadow boundary, in full agreement with the dual electromagnetic behavior predicted for PMC interfaces. Beyond its theoretical completeness, the proposed formulation provides a compact and computationally efficient framework for diffraction modeling and hybrid solver integration, offering practical applicability to magnetic coatings, low-RCS reflectors, and metasurface-based structures.
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DAİRESEL AÇIKLIKTAN OLUŞAN TOPLAM ALANLARIN KARAKTERİZASYONU: OPAK, PEC VE PMC YÜZEYLER İÇİN KARŞILAŞTIRMALI ANALİZ
(Bursa Uludağ Üniversitesi, 2026-01) Altınel, Mustafa; Yalçın, Uğur; 414019
Bu çalışma, dairesel bir açıklıktan yayılan toplam alanların Opak, Mükemmel Elektrik İletken (PEC) ve Mükemmel Manyetik İletken (PMC) yüzeylerdeki davranışlarını karşılaştırmalı olarak incelemektedir. Toplam alan hesaplamalarında Sınır Kırınım Dalgası Teorisi (SKDT) ile Genelleştirilmiş SKDT (GSKDT) yöntemleri kullanılmış, analizler, Miyamoto ve Wolf tarafından tanımlanan vektör potansiyeli temeline dayandırılmıştır. Elde edilen non-uniform toplam alan ifadeleri, Detour parametresi ve Fresnel fonksiyonunun asimptotik özellikleri kullanılarak uniform forma dönüştürülmüştür. Opak yüzeylerde yalnızca gelen dalga dikkate alınırken, PEC ve PMC yüzeylerde hem gelen hem de yansıyan dalgalar hesaba katılmıştır. Farklı açıklık yarıçapları ve gözlem mesafeleri için toplam alanın uzaysal dağılımı grafiksel olarak karşılaştırılmış, yüzey tiplerinin alan üzerindeki etkileri ayrıntılı biçimde analiz edilmiştir. Sonuçlar, toplam alanın genlik ve faz karakteristiğinin yüzey tipine bağlı olarak belirgin biçimde değiştiğini göstermekte; özellikle PEC yüzeylerde yüksek frekanslı girişim desenleri, opak yüzeylerde ise daha düşük genlikli ve düzgün bir dağılım gözlenmektedir. Elde edilen bulgular, yüzey özelliklerinin toplam alan davranışı üzerindeki rolünü hem nitel hem de nicel olarak ortaya koymakta; anten tasarımı, elektromanyetik kalkanlama ve radar kesit alanı (RCS) azaltımı gibi mühendislik uygulamalarında yüzey seçimi ve optimizasyonu için yol gösterici bir referans sunmaktadır.
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CHANCERY CURSİVE EL YAZISININ EVRİMİ: RÖNESANS’TAN GÜNÜMÜZE KALİGRAFİK KİMLİK VE ÖĞRETİM PARADİGMALARINDAKİ DÖNÜŞÜM
(Deniz Yengin, 2026-03) Kipdemir, Serdar; 341649
Bu çalışma, 16. yüzyılda ortaya çıkan Cancellaresca Corsiva (Chancery Cursive) yazısının modern Formal Italic'e evrimini beş yüzyıllık tarihsel süreçte incelemektedir. Araştırmanın odağı, yazının biçimsel dönüşümü ile öğretim paradigmalarındaki değişim arasındaki organik bağdır. Rönesans'ta La Operina (1522) gibi kılavuzlar ve matbaa etkisiyle şekillenen stil, 20. yüzyılda Edward Johnston'ın rekonstrüksiyonu ve Alfred Fairbank'ın pedagojik sistematizasyonuyla Formal Italic'e dönüşmüştür. Çalışmada ayrıca, öğretim yöntemlerinin usta-çırak modelinden standart müfredatlara ve dijital platformlara evrimi analiz edilmektedir. Bulgular, Chancery Cursive'ün evriminin salt estetik bir değişim olmadığını; “zanaat”, “disiplin” ve “ağ-tabanlı pratik” kimlikleriyle, hakim bilgi aktarım biçimlerine uyum sağladığını göstermektedir. Sonuç olarak, bu geleneğin sürdürülebilirliği, estetik değerini korurken, çağın pedagojik araçlarını yeniden yorumlama becerisine bağlıdır. Chancery Cursive'ün katmanlı mirası, tarihsel bilinçle dijital imkânlar buluşturularak, kaligrafi eğitimi ve tipografik tasarımda gelecekte de referans olmayı sürdürecektir.
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Evaluation of uniform diffraction behavior from circular apertures on opaque and perfectly conductive surfaces using BDW theories
(Emerald, 2026-02) Altınel, Mustafa; Yalçın, Uğur; 414019
This study presents a unified and comparative analysis of uniform diffraction fields generated by circular apertures on three canonical surface types: opaque, perfectly electric conductive (PEC) and perfectly magnetic conductive (PMC). This study aims to explore how these boundaries influence field uniformity and angular behavior under identical conditions.Design/methodology/approachThe classical boundary diffraction wave (BDW) theory is applied to the opaque case, and an extended BDW formulation is developed for PEC and PMC surfaces to account for reflective effects. Analytical expressions are derived, and numerical simulations are conducted to examine the impact of aperture size and observation distance.FindingsThe results reveal that PEC and PMC surfaces introduce significant modifications to the angular distribution of the diffracted field, including phase reversals and amplitude oscillations. The extended BDW model successfully predicts these behaviors, particularly near shadow boundaries and axial zones.Research limitations/implicationsThe study is limited to idealized geometries and monochromatic wave excitation. It does not yet consider material losses or complex aperture shapes. Future work may expand this framework to more realistic electromagnetic structures.Practical implicationsThe findings can help electromagnetic engineers optimize antenna design, stealth surfaces and metastructures by offering better control over field uniformity and diffraction behavior across different surface types.Social implicationsWhile the work is theoretical, it supports technological development in sectors like communication, defense and sensing, contributing indirectly to infrastructure reliability and performance.Originality/valueTo the best of the authors' knowledge, this is the first unified parametric study that simultaneously evaluates opaque, PEC and PMC surfaces using classical and extended BDW approaches. It introduces a novel high-frequency framework for comparing uniform diffraction field behavior across distinct boundary conditions.
