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On Stable Difference Schemes for the Solution of Soliton Type Coupled Sine-Gordon Equations in the Weak Sense
No full textIn the present paper numerical solution of the nonlinear coupled system of sine-Gordon equations is studied in the weak sense. A first-order accurate and two second-order accurate unconditionally stable difference schemes corresponding to the system of sine-Gordon equations are considered. Solutions of these difference schemes are presented in the space of distributions by variational methods. The fixed point theory and the finite difference method are combined in the numerical implementations, carried out in MATLAB, in order to verify the theoretical results
Bi-objective optimization of human-robot collaborative mixed-model multiple assembly lines considering model assignment and energy consumption
No full textA critical yet often overlooked challenge in mixed-model and multi-line production environments is the model-line assignment problem–deciding which product models should be allocated to which assembly lines. This decision has a profound effect on overall production efficiency, as it directly influences subsequent balancing and scheduling decisions. The integration of collaborative robots (cobots) into these environments further complicates this task. Despite its significance, the joint consideration of model-line assignment and robotic line balancing has received limited attention in the literature. This study addresses this gap by formulating the robotic mixed-model multiple assembly line balancing problem with simultaneous model-line assignment (MLA-RMMALB) and proposing a multi-objective mixed-integer programming model. The model aims to minimize total production costs and PM2.5 emissions resulting from cobots’ energy consumption. To handle the complexity of the problem, a Non-dominated Sorting Genetic Algorithm II (NSGA-II) is developed as a solution approach. The model's effectiveness is demonstrated through a numerical example involving 21 tasks and benchmark problems from the literature. Solutions obtained under integrated model-line assignment are compared with random assignment scenarios, revealing significant performance gains in both objectives. NSGA-II proves capable of delivering optimal or near-optimal solutions efficiently for small- and medium-sized instances, and high-quality results for larger problems. This study contributes to literature by addressing critical challenges in multi-line mixed-model production by jointly considering model-line assignment, cobot heterogeneity, and the parallel operation of cobots and human workers. It proposes NSGA-II as an effective solution method for this complex problem. Practically, the study provides a decision-support tool for manufacturers aiming to optimize both cost-efficiency and environmental performance in robotic assembly systems. The findings are especially relevant for industries adopting cobots in high-variety production environments where these factors must be simultaneously managed
Structural characterization, biofunctionality, and in vitro digestibility of exopolysaccharides from Lactiplantibacillus plantarum E1K2R2
No full textRecently, microbial polysaccharides have gained significant importance as biomaterials, owing to their health benefits and inherent biocompatibility. Accordingly, the present study focuses on characterizing exopolysaccharides (EPS) from Lactiplantibacillus plantarum E1K2R2, investigating their structure, biocompatibility, antioxidant properties, antitumor effects, and digestibility under simulated saliva and gastrointestinal conditions. The EPS was identified as a heteropolysaccharide primarily composed of galactose and glucose monomers, with a molecular weight ranging from 3.15 × 103 to 3.95 × 105 Da. The measured particle size was 498.7 nm, while its negative zeta potential (− 7.20 mV) pointed to an acidic profile. FTIR analysis further supported this finding by identifying characteristic hydroxyl and carboxyl functional groups at 3273.57 cm−1 and 1646.91 cm−1, respectively. 1H NMR spectroscopy demonstrated that monomers in the EPS were linked by α- glycosidic bonds. Functionally, the EPS displayed dose-dependent antioxidant activity within 0.1–1 mg/mL, equivalent to 0.07–0.17 mM/mL ascorbic acid, with ABTS·+ radical scavenging ranging from 33.63 to 65.63%, demonstrating strong free radical–scavenging potential. In cytotoxicity assays, the EPS moderately inhibited HepG2 cell proliferation (6.49–20.53%) while maintaining 95% viability in normal HUVEC cells at 1 mg/mL after 24 h of incubation, indicating selective cytotoxicity toward cancer cells and good biocompatibility with normal cells. The EPS also resists simulated saliva and gastrointestinal conditions and promotes the growth of some potential probiotic lactic acid bacteria, indicating that digestive conditions do not adversely affect the EPS. These findings suggest that EPS has promising applications due to its antioxidant, antitumor, and prebiotic contexts, supported by its high biocompatibility
Enhancing efficiency in Peltier-cooled atmospheric water harvesting: A mathematical modeling and experimental study
No full textWater scarcity is one of the biggest global challenge, threatening current generation and necessitating alternative solutions. Among various technologies, atmospheric water harvesting systems offer a viable solution. The objective of this study is to present and assess an innovative geometry for Peltier-cooled atmospheric water harvesting system intended to improve drinkable water production through enhancing both mixing and heat transfer in the cold-side extended surfaces. The initial section of this study involves mathematical modeling. Findings of modeling section, illustrate an output of 1.97 L/day under conditions of 84.8% relative humidity and an ambient temperature of 32°C. The second section involves the design, fabrication, and performance evaluation of the system. The experimental observations indicate a water generation of 1.97 L/day in Test 1 (84.8% relative humidity, 32˚C), 1.63 L/day in Test 2 (85.8% relative humidity, 24.2˚C), 1.45 L/day in Test 3 (79% relative humidity, 25.4˚C), 1.29 L/day in Test 4 (76% relative humidity, 30˚C), and 1.13 L/day in Test 5 (69% relative humidity, 22.5˚C). These findings demonstrates the significant impact of environmental factors on the system's water generation performance. Moreover, novel geometry of the air inlet and exit channels improved the effectiveness of the water harvesting of the prototype across all test scenarios when compared with results reported in the literature. The outputs derived from modeling and experimental analysis, exhibit a strong correlation, thereby validating the model and highlighting the capability of the proposed system as a sustainable approach to global water scarcity problems
KENT KİMLİĞİNİ YANSITACAK VE İKLİM DEĞİŞİKLİĞİNE UYUM SAĞLAYABİLECEK ODUNSU BİTKİLER: ARDAHAN
No full textTailoring the corrosion behavior of hot-pressed aluminium-CeO2 composites
No full textThis study aimed to reveal the corrosion behavior of Al-CeO2 composites. Samples were fabricated with 1 and 10 wt% reinforcement ratios, respectively. In-situ phases like complex oxide and intermetallic were observed at higher CeO2 content. The corrosion behavior of samples was significantly developed with CeO2 and in-situ oxides. Particularly, the corrosion rate was reduced by CeO2 particles. Furthermore, usage of 10 wt% CeO2 increased the charge transfer resistance to 1467.02 Ω. It can be stated that CeO2 particles and in-situ oxides were favorable for enhanced corrosion behavior
KEREM OPERASI İLE TÜRK MÜZİĞİ ARASINDAKİ İLİŞKİNİN METİNLERARASILIK KURAMI ÜZERİNDEN İNCELENMESİ
No full textCumhuriyet döneminde Türkiye’de gerçekleştirilen kültürel reformların en dikkat çekici yönlerindenbiri, müzik alanında gerçekleştirilen devrimdir. Atatürk’ün öncülüğünde başlatılan Türk MüzikDevrimi’nin ilk ve öncelikli sanatı olarak opera, modernleşme sürecinin simgesel bir aracı hâlinegelmiştir. 1934 yılında İran Şahı Rıza Pehlevi’nin Ankara ziyaretine ithafen Adnan Saygun tarafındanbestelenen Özsoy operası, Türkiye’de bestelenen ilk ulusal opera olarak bu dönüşümün başlangıçnoktasını oluşturur. Ardından Taşbebek ve Bayönder operalarıyla birlikte Türk bestecilerinin sahnedegörünürlüğü artmış, bu sanat dalı Cumhuriyet ideallerinin sanatsal bir temsiline dönüşmüştür.1946’da sahnelenen Yunus Emre Oratoryosu’ndan sonra Saygun’un ilk büyük opera eseri olan Kerem(1953), hem müzikal hem de tematik açıdan Türk müziği ile Batı formunun kaynaşmasının simgesiolmuştur. Bu makale, Kerem Operası’nın yapısında yer alan Türk müziği unsurlarını metinlerarasılıkkuramı çerçevesinde incelemekte ve eseri, dönemin sosyo-politik yapısı içinde konumlandırarak TürkMüzik Devrimi’nin yeni ulus kimliği inşasındaki işlevini tartışmaktadır. Saygun’un yerel makamdizilerini modern armoniyle bütünleştiren yaklaşımı, Anadolu’ya özgü müzikal renkleri evrensel birestetik anlayışla buluşturur. Böylece opera hem sanatsal hem de ideolojik anlamda Cumhuriyet’inkültürel dönüşüm projesinin en güçlü taşıyıcılarından biri hâline gelir. Araştırma, Kerem Operası’nınyalnızca bir müzik eseri değil, aynı zamanda Cumhuriyet ideolojisinin sanatsal temsili olduğunuortaya koymaktadır. Eserin mistik aşk anlatımı ile “yeni insan” idealini buluşturan yapısı, sanatınulusal kimlik inşasındaki rolünü somut biçimde göstermektedir.One of the most striking aspects of the cultural reforms carried out in Turkey during the Republicanera is the revolution implemented in the field of music. Opera, as the first and foremost art form ofthe Turkish Music Revolution initiated under Atatürk’s leadership, became a symbolic instrument of the modernization process. The opera Özsoy which composed by Adnan Saygun in 1934 indedication to the visit of the Iranian Shah Reza Pahlavi to Ankara, constitutes the starting point ofthis transformation as the first national opera composed in Turkey. Subsequently, with the operasTaşbebek and Bayönder, the visibility of Turkish composers on the stage increased, and this art formevolved into an artistic representation of Republican ideals.After the staging of the Yunus Emre Oratorio in 1946, Saygun’s first major operatic work, Kerem(1953), became a symbol of the fusion of Turkish music and Western form, both musically andthematically. This article examines the elements of Turkish music embedded in the structure of theopera Kerem within the framework of intertextuality theory and discusses the work’s function in theconstruction of a new national identity during the Turkish Music Revolution by situating it within thesocio-political context of its period. Saygun’s approach of integrating local modal scales with modernharmony brings together musical colors unique to Anatolia with a universal aesthetic sensibility.Thus, opera becomes one of the most powerful carriers of the Republic’s cultural transformationproject, both artistically and ideologically. The study demonstrates that the opera Kerem is not merelya musical work, but also an artistic representation of Republican ideology. The work’s structure,which brings together a mystical love narrative with the ideal of the “new individual,” concretelydemonstrates the role of art in the construction of national identity. </p
Axially quinoline-substituted silicon phthalocyanines: Synthesis, characterization, molecular modeling and biological evaluation against cholinesterases and carbonic anhydrases
No full textIn this study, two axially 6-hydroxyquinoline substituted silicon phthalocyanine (2a) and 5‑chloro-8-hydroxyquinoline substituted silicon phthalocyanine (3a) compounds were synthesized and the compounds were characterized by spectroscopic techniques. IC₅₀ values were determined as 231.00 ± 1.09, 0.58 ± 0.16, 3.09 ± 0.25 and 11.55 ± 0.36 µM, for compound 2a, and 13.58 ± 0.28, 138.60 ± 0.36, 9.90 ± 0.25 and 63.00 ± 0.19 µM for compound 3a against AChE, BChE, hCA I, and hCA II enzymes respectively. Compound 2a has effective inhibition against BChE, hCA I and hCA II and compound 3a has effective inhibition against AChE and hCA I. Binding affinities of the synthesized compounds were clarified through molecular docking studies performed on four target enzymes: AChE, BChE, hCA I and hCA II. Molecular dynamics simulations were carried out to gain deeper insight into the dynamic behavior of the compounds, The 2a–BChE complex exhibited the highest stability
Radiation dose assessment to abdominal and pelvic organs in fluoroscopy-guided lumbar epidural steroid injections: A phantom-based analysis
No full textThis study aims to quantify organ-specific radiation doses during transforaminal lumbar epidural steroid injections (ESI) performed under C-arm fluoroscopic guidance using a phantom-based experimental setup. An Alderson Rando anthropomorphic phantom was used to simulate the human anatomy. A total of 32 MTS-100 thermoluminescent dosimeters (LiF:Mg,Ti) were placed at predefined anatomical sites representing abdominal and pelvic organs. Fluoroscopy was conducted using a Siemens Artis Zee system with standard clinical protocols at gantry angles of 0°, 45°, and 180°. The absorbed doses were measured, and organ-specific distributions were analysed. The highest radiation doses were recorded in the left kidney, pancreas, and spleen. Reproductive organs such as the upper ovaries and uterus also received moderate exposure, while the bladder and medulla spinalis received the lowest doses. It can be concluded that even the fluoroscopic beam is localized to the lumbar spine, scattered radiation can result in significant exposure to critical organs, which underlines the importance of optimized imaging protocols and targeted radiation protection measures