Atılım Academic Archive (Atılım University)
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An Experimental Study on Ultrasonic-Assisted Drilling of CFRP Composites with Minimum Quantity Lubrication
No full textThe increasing use of carbon fiber reinforced polymer (CFRP) composites in industries such as aerospace, due to its high strength-to-weight ratio, durability, and resistance to corrosion has led to a growing demand for more efficient machining processes. However, the multilayered structure of CFRP composites, composed of densely packed fibers, presents significant challenges during machining. Additionally, when cutting fluids are used to improve effective cooling and lubrication, the material tends to absorb the fluid, causing damage and leading to problem of weaking of composite structure. To address these issues, this study compares ultrasonic-assisted drilling (UAD) and minimum quantity lubrication (MQL) techniques with conventional drilling (CD) and dry cutting to improve the performance of CFRP composite drilling. The results show that using UAD and MQL together reduced thrust force by up to 27%, improved surface roughness inside the holes by up to 31%, reduced improved hole diameter, cylindricity, roundness, and delamination
Termination of Insurance Contracts
No full textSigorta hukuku bakımından sigorta ilişkisi, sigorta sözleşmesinin kurulmasıyla doğar. Bu sözleşmesel ilişki, yalnızca taraflar arasında doğan edim yükümlülüklerini değil, aynı zamanda sigorta sözleşmesinin kurulma, devam etme ve sona erme aşamalarında ortaya çıkan özel borç ilişkilerini de kapsar. Bu nedenle sigorta sözleşmesine bağlı borçların ve yükümlülüklerin, sözleşmenin sona ermesi halinde devam edip etmeyeceği yahut yeni borçların doğup doğmayacağı hususu, sigorta sözleşmesinin kapsamı ve sona erme şekli ile yakından ilişkilidir. Bu tez çalışması, sigorta sözleşmelerinin sona erme nedenleri ile bu sona ermenin hukuki sonuçlarını incelemeyi amaçlamaktadır. Sözleşmenin hangi nedenlerle sona erebileceğinin tespiti, bu ilişkinin akıbetini değerlendirmek açısından ön koşuldur. Genel borçlar hukuku çerçevesinde, sigorta sözleşmeleri örneğin sürenin dolmasıyla kendiliğinden sona erebilir. Bununla birlikte, Türk Ticaret Kanunu'nda sigorta sözleşmesine özgü sona erme nedenlerine ayrıca yer verilmiştir. Bu nedenler, taraf iradesinden bağımsız olarak sözleşmeyi sona erdiren nedenler (iradi olmayan sona erme) ve taraf iradesine dayalı sona erdiren nedenler (iradi sona erme) şeklinde iki grupta değerlendirilebilir. İlki; (1) rizikonun veya sigorta olayının gerçekleşmesi, (2) sigorta menfaatinin ortadan kalkması ve (3) sigortacının iflasıdır. İkincisi ise; (1) sözleşmenin feshi, (2) cayma hakkının kullanılması ve (3) can (meblağ) sigortalarında sigortadan ayrılmadır. Sigorta sözleşmesinin sona ermesi yalnızca sona erdiren nedenin tespitiyle sınırlı olmayıp, bu sona ermeye bağlı olarak doğan sonuçların da bütüncül bir yaklaşımla ele alınmasını gerektirir. Bu kapsamda, çalışmada sigorta sözleşmesinin sona ermesinin hüküm ve sonuçlarına göre değerlendirme yapılmıştır. Sigorta sözleşmesinin sona ermesinin hüküm sonuçları altı başlık altında incelenmiştir: (1) Prim iadesi, (2) ayrılma (iştira) değerinin ödenmesi, (3) prime hak kazanma, (4) sigorta tazminatının ödenmesi, (5) sigorta bedelinin ödenmesi, (6) dar anlamda borcu sona erdiren bir neden olan takas ile zamanaşımının hüküm ve sonuçları.The insurance contract. This contractual relationship encompasses not only the performance obligations arising between the parties but also the specific debt relations that emerge during the formation, continuation, and termination phases of the insurance contract. Therefore, whether the obligations and debts arising from the insurance contract continue upon the termination of the contract, or whether new obligations may arise, is closely related to the scope and mode of termination of the insurance contract. This thesis aims to examine the grounds for termination of insurance contracts and the legal consequences of such termination. Determining the reasons for which the contract may be terminated is a prerequisite for assessing the fate of this legal relationship. Although insurance contracts may, for example, be terminated automatically upon expiry within the framework of general law of obligations, the Turkish Commercial Code also contains specific provisions regulating termination. These reasons can be classified into two groups: those that terminate the contract by operation of law or ex lege, and those that result from the unilateral declaration or mutual intention of the parties not to continue the contract. The former includes: (1) the occurrence of the risk or the insured event, (2) the disappearance of the insurable interest, and (3) the insurer's bankruptcy. The latter includes: (1) termination of the contract, (2) exercise of the right of withdrawal, and (3) withdrawal from the insurance in life (sum) insurance contracts. The termination of an insurance contract is not limited solely to identifying the ground for termination; it also requires a comprehensive evaluation of the legal consequences arising from such termination. Within this scope, the study assesses the termination of the insurance contract based on its legal effects and consequences. The legal consequences of the termination of the insurance contract are examined under six main headings: (1) refund of premiums, (2) payment of the separation (buyback) value, (3) entitlement to the premium, (4) payment of insurance indemnity, (5) payment of the insured amount, (6) consequences of swap and prescription, both of which constitute causes for termination of obligations in the narrow sense
Evaluating Efficacy and Outcomes: Comparison of Laser Treatment and Crystallized Phenol in Pilonidal Sinus Disease
No full textEMRAL, AHMET CIHANGIR/0000-0003-3976-1387Objective The aim of this study is to comprehensively evaluate the efficacy of laser ablation and crystallized phenol application in the treatment of pilonidal sinus disease, focusing on treatment success, recurrence rates, complications, and the patients' return to normal life.Material and method Data from patients treated for pilonidal sinus disease with laser ablation and crystallized phenol application at our clinic between January 2020 and September 2023 were retrospectively reviewed. Preoperative data including pit counts, disease stage, preoperative pilonidal abscess history, disease duration (week), treatment success, recurrence/persistent disease, postoperative complications, healing time (days), and visual analogue scale (VAS) scores on postoperative days 1 and 7, as well as return to normal life (days), were analyzed.Results A total of 121 patients were included in the study, with 51 receiving laser ablation and 70 receiving crystallized phenol application. The postoperative outcomes revealed that the wound healing period and postoperative VAS values were statistically significantly better in the laser ablation group.Conclusion Wound healing was faster and postoperative pain was less in the laser group compared to the phenol group. According to this study, both methods can successfully treat the disease in selected cases.Science Citation Index Expande
Unveiling the Impact of Vernalisation on Seed Oil Content and Fatty Acid Composition in Rapeseed (Brassica Napus L.) Through Simulated Shorter Winters
No full textClimate change is leading to warmer winters world-wide with an increasing number of extreme events every year. Studies show that winter varieties of rapeseed are particularly impacted negatively by global warming. This study investigates the molecular, physiological, and biochemical effects of diverse vernalisation scenarios (i.e., the vernalisation models) on rapeseed plants and seeds. The winter and spring varieties of rapeseed (Brassica napus L.) were subjected to short durations of vernalisation (3 and 4 weeks) as well as to 6- and 8-week long vernalisation interrupted by 1-week devernalisation intervals at warm temperatures. Our results reveal a notable difference in vernalisation responsiveness in major floral regulator FLC orthologues between the late-flowering winter variety, Darmor, the early-flowering winter variety, Bristol, and the spring variety, Helios, after 3 weeks of vernalisation. Within the three FLC genes (BnaFLCA02, BnaFLCA10, and BnaFLCC02) analysed in this study, BnaFLCA10 emerged as the most responsive to vernalisation in all three varieties. The vernalisation duration significantly influenced seed oil content and fatty acid composition in both Bristol and Helios varieties. In Bristol, the 2 + 6w vernalisation model in which vernalisation was interrupted for 1 week after 2 weeks of vernalisation and continued for another 4 weeks consistently resulted in the highest oil content and oleic acid percentage. The interrupted vernalisation (2 + 4w and 2 + 6w) also led to increased monounsaturated fatty acids across all 3 years. In Helios, non-vernalised plants produced seeds with the lowest oil content, and vernalisation duration positively correlated with both seed oil content and oleic acid percentage. Our findings unveil a robust correlation between vernalisation and seed oil content, as well as fatty acid composition in rapeseed. © 2025 The Author(s). Journal of Agronomy and Crop Science published by Wiley-VCH GmbH.TUBITAK 2209‐A; TUBITAK 2209-A; Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, TÜBİTAK, (120Z278); Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, TÜBİTAKScience Citation Index Expande
The Influence of Pain Characteristics on Insomnia, Knee Function, and Muscle Strength in Patients With Knee Osteoarthritis
No full textScience Citation Index Expande
Space Efficiency in Tall Timber Buildings: A Comprehensive Review
No full textTall timber construction is gaining popularity due to its notable environmental and economic benefits throughout its lifecycle. Maximizing space efficiency in these buildings is a key factor in ensuring project viability. However, there has been a lack of comprehensive research on the space efficiency of these projects. This study focused on analyzing 50 tall buildings (over eight stories) globally to improve insights into the design elements that affect space use. The key findings include: i) predominant architectural configurations incorporate residential functions, a centrally positioned core, and prismatic building forms; ii) composite materials are the most utilized, with shear-walled frame systems being the preferred structural solution; and iii) average space efficiency is 84%, with core areas accounting for 11% of the gross floor area, ranging from 71% and 4% at the lower end to 93% and 21% at the upper end. This study provides valuable guidance for architects and other key participants engaged in the planning and construction of tall timber buildings. © 2025 Ilgın and Aslantamer
Global Insights Into Food Fraud From Location-Based Analysis: Food Adulteration in Turkey
No full textBackgroundFood fraud and adulteration pose critical global challenges impacting economic stability and public health. This study examines the prevalence and characteristics of food fraud incidents in Turkey, an international player in the food supply chain. Controls carried out from production to consumption reveal many fraudulent events worldwide.ResultsData collected by the Ministry of Agriculture and Forestry of T & uuml;rkiye from 2012 to 2022, covering 4007 incidents and 7180 specific cases of adulteration, form the basis of this analysis. The study categorizes food fraud by region, product group and type of fraud, revealing trends and patterns. Key findings indicate a higher incidence of fraud in milk, meat and vegetable oil products, including the detection of drug-based adulteration having potential for serious health consequences.ConclusionAt most importance, we demonstrated the importance of risk-based food inspections and the development of new detection technologies to enhance food safety. The results are fundamental for more effective food inspections in terms of risk-based conformity assessment approaches or developing new methods, devices and analysis kits in terms of scientific and technological approaches. Still, they can also significantly improve future food safety measures. These insights are aimed at informing global food safety strategies and policymaking, contributing to a safer and more transparent food supply chain. (c) 2025 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.Science Citation Index Expande
Cu Doping of Sb2Se3 Thin Films Via Thermal Evaporation: Tailoring Structural and Optical Properties for Enhanced Photovoltaic Performance
No full textIsik, Mehmet/0000-0003-2119-8266In this study, Cu-doped Sb2Se3 thin films were successfully grown using the thermal evaporation method, and their structural and optical properties were systematically investigated. Three different samples with thickness of similar to 400 nm were analyzed: undoped, 1 %, and 2 % Cu-doped Sb2Se3. X-ray diffraction (XRD) analysis revealed well-defined peaks, confirming the orthorhombic crystalline nature of the films. Scanning electron microscopy (SEM) images showed a uniform surface morphology without any significant defects. The optical properties were examined through transmission measurements. The band gap energy determined by Tauc analysis decreased from 1.27 to 1.21 eV as the Cu doping increased from 0 % to 2 %, indicating that Cu incorporation modifies the electronic structure of Sb2Se3. Similarly, Urbach energy increased from 0.148 to 0.168 eV depending on Cu content, suggesting a rise in localized states due to increased structural disorder. These findings demonstrate that Cu doping influences the electronic structure and defect states of Sb2Se3, which is crucial for optimizing its performance in photovoltaic and optoelectronic applications
A Comparative Analysis of Progestin-Primed Ovarian Stimulation Versus GnRH Antagonists Protocols Pertaining To Stimulation Parameters and Embryological Outcomes in Patients With Endometrioma
No full textResearch question: Do embryo parameters and live birth rates differ between patients with endometrioma undergoing a freeze-all strategy using either GnRH antagonists or progestin-primed ovarian stimulation (PPOS)? Design: This retrospective cohort study was conducted at Bahceci Health Group from January 2021 to January 2023. Inclusion criteria were females aged 20–40 with confirmed endometriosis, using either GnRH antagonists or PPOS ovarian stimulation, and opting for freezing all embryos without fresh embryo transfer (ET). A total of 543 patients were analyzed, with the primary outcome being usable embryos at cleavage stage and secondary outcomes including distribution of embryo quality, clinical pregnancy, and live birth rate. Results: For the GnRH antagonist arm, the median (25th-75th percentiles) total gonadotropin dose required during stimulation was significantly higher (2725 [2100–3587.5] vs. 2400 [2050–3075] IU, p = 0.001) and duration was longer (11 [10–12] vs. 10 [9–11] days, p = 0.01), although number of mature oocytes and maturation and fertilization rates were similar in both arms. However, the linear regression analysis revealed that the number of usable day-three embryos was higher with the PPOS protocol than with the GnRH antagonist protocol (OR: 0.890, CI 95%: 0.226 – 1.554, p= 0.009). Particularly in patients that had undergone FET, the respective live birth rates were 50.0% and 54.6% in GnRH antagonist and PPOS arms, respectively, without any statistical significance (p= 0.365). Conclusion: In patients with endometrioma, the PPOS protocol over GnRH antagonists might potentially enhance the quantity of usable cleavage-stage embryos while showing no significant impact on the number of collected oocytes. © 2025 Elsevier B.V., All rights reserved.Science Citation Index Expande
Binary Tree Blockchain of Decomposed Transactions
No full textCulha, Davut/0000-0001-5486-1867Widespread adoption of blockchain technologies requires scalability. To achieve scalability, various methods are applied, including new consensus algorithms, directed acyclic graph solutions, sharding solutions, and off-chain solutions. Sharding solutions are particularly promising as they distribute workload across different parts of the blockchain network. Similarly, directed acyclic graphs use graph data structures to distribute workload effectively. In this work, a binary tree data structure is used to enhance blockchain scalability. Binary trees offer several advantages, such as the ability to address nodes with binary numbers, providing a straightforward and efficient method for identifying and locating nodes. Each node in the tree contains a block of transactions, which allows for transactions to be directed to specific paths within the tree. This directionality not only increases scalability by enabling parallel processing of transactions but also ensures that the blockchain can handle a higher volume of transactions without becoming congested. Moreover, transactions are decomposed into transaction elements, improving the immutability of the binary tree blockchain. This novel decomposition process helps to minimize the computational overhead required for calculating account balances, making the system more efficient. By breaking down transactions into their fundamental components, the system can process and verify transactions more rapidly and accurately. This approach effectively realizes implicit sharding using a binary tree structure, distributing the processing load more evenly and reducing bottlenecks. The proposed method is simulated to assess its performance. Experimental results demonstrate that the proposed method achieves a significantly higher transaction throughput of 32307 transactions per second. Furthermore, block generation times decrease as the system scales, with an average block generation time of 0.13 seconds, underscoring the efficiency of the binary tree blockchain structure.Science Citation Index Expande